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Note: This page contains sample records for the topic "time series models" from the National Library of EnergyBeta (NLEBeta).
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they are not comprehensive nor are they the most current set.
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1

Time dependent Directional Profit Model for Financial Time Series Forecasting  

E-Print Network (OSTI)

Time dependent Directional Profit Model for Financial Time Series Forecasting Jingtao YAO Chew Lim@comp.nus.edu.sg Abstract Goodness­of­fit is the most popular criterion for neural network time series forecasting. In the context of financial time series forecasting, we are not only concerned at how good the forecasts fit

Yao, JingTao

2

Optimal aggregation of linear time series models  

Science Conference Proceedings (OSTI)

Aggregation is a central and mainly unsolved problem in econometrics. When considering linear time series models, a widely used method is to replace the disaggregate model by an aggregative one in which the variables are grouped and replaced by sums ... Keywords: Aggregation, Industrial classification, Threshold accepting

J. Chipman; P. Winker

2005-04-01T23:59:59.000Z

3

Forecasting Electricity Demand by Time Series Models  

Science Conference Proceedings (OSTI)

Electricity demand is one of the most important variables required for estimating the amount of additional capacity required to ensure a sufficient supply of energy. Demand and technological losses forecasts can be used to control the generation and distribution of electricity more efficiently. The aim of this paper is to utilize time series model

E. Stoimenova; K. Prodanova; R. Prodanova

2007-01-01T23:59:59.000Z

4

A Potential-Field Approach to Financial Time Series Modelling  

Science Conference Proceedings (OSTI)

We present a new approach to the problem of time series modelling that captures the invariant distribution of time series data within the model. This is particularly relevant in modelling economic and financial time series, such as oil prices, that ... Keywords: diffusion, multiple attraction regions, potential function, price

S. Borovkova; H. Dehling; J. Renkema; H. Tulleken

2003-10-01T23:59:59.000Z

5

Structural Time Series Models and Trend Detection in Global and Regional Temperature Series  

Science Conference Proceedings (OSTI)

A unified statistical approach to identify suitable structural time series models for annual mean temperature is proposed. This includes a generalized model that can represent all the commonly used structural time series models for trend ...

Xiaogu Zheng; Reid E. Basher

1999-08-01T23:59:59.000Z

6

Large margin mixture of AR models for time series classification  

Science Conference Proceedings (OSTI)

In this paper, we propose the large margin autoregressive (LMAR) model for classification of time series patterns. The parameters of the generative AR models for different classes are estimated using the margin of the boundaries of AR models as the optimization ... Keywords: Generative and discriminative hybrid models, Large margin autoregressive model, Large margin mixture autoregressive model, Outlier detection, Rejection option, Time series classification

B. Venkataramana Kini; C. Chandra Sekhar

2013-01-01T23:59:59.000Z

7

Forecasting Natural Gas Prices Using Time Series Models .  

E-Print Network (OSTI)

??The objective of this thesis is to estimate the natural gas component of the All Urban Consumer Price Index (CP-U) using time series forecasting models. (more)

Berg, Andrew

2006-01-01T23:59:59.000Z

8

A new class of hybrid models for time series forecasting  

Science Conference Proceedings (OSTI)

Applying quantitative models for forecasting and assisting investment decision making has become more indispensable in business practices than ever before. Improving forecasting especially time series forecasting accuracy is an important yet often difficult ... Keywords: Artificial neural networks (ANNs), Auto-Regressive Integrated Moving Average (ARIMA), Hybrid models, Probabilistic neural networks (PNNs), Time series forecasting

Mehdi Khashei; Mehdi Bijari

2012-03-01T23:59:59.000Z

9

A Sparse Regression Mixture Model for Clustering Time-Series  

Science Conference Proceedings (OSTI)

In this study we present a new sparse polynomial regression mixture model for fitting time series. The contribution of this work is the introduction of a smoothing prior over component regression coefficients through a Bayesian framework. This is done ... Keywords: Clustering time-series, Expectation-Maximization (EM) algorithm, Regression mixture model, sparse prior

K. Blekas; Nikolaos Galatsanos; A. Likas

2008-10-01T23:59:59.000Z

10

Chaotic time series forecasting using locally quadratic fuzzy neural models  

Science Conference Proceedings (OSTI)

Time series forecasting in highly nonlinear and chaotic systems is a challenging research area with a variety of applications in economics, environmental sciences and various fields of engineering. This paper presents a novel Locally Quadratic Fuzzy ... Keywords: chaotic time series, forecasting, locally quadratic neural fuzzy model

Mohammad J. Mahjoob; Majid Abdollahzade; Reza Zarringhalam; Ahmad Kalhor

2008-05-01T23:59:59.000Z

11

Bayesian Mixture of AR Models for Time Series Clustering  

Science Conference Proceedings (OSTI)

In this paper we propose a Bayesian framework for estimation of parameters of a mixture of autoregressive model, for time series clustering. The proposed approach is based on variational principles and provides a tractable approximation to the true posterior ...

Venkataramana Kini B; C. Chandra Sekhar

2009-02-01T23:59:59.000Z

12

Time series of count data: modeling, estimation and diagnostics  

Science Conference Proceedings (OSTI)

Various models for time series of counts which can account for discreteness, overdispersion and serial correlation are compared. Besides observation- and parameter-driven models based upon corresponding conditional Poisson distributions, a dynamic ordered ... Keywords: Efficient importance sampling, Markov chain Monte Carlo, Observation-driven model, Ordered probit, Parameter-driven model

Robert C. Jung; Martin Kukuk; Roman Liesenfeld

2006-12-01T23:59:59.000Z

13

A comparison study between fuzzy time series model and ARIMA model for forecasting Taiwan export  

Science Conference Proceedings (OSTI)

This study compares the application of two forecasting methods on the amount of Taiwan export, the ARIMA time series method and the fuzzy time series method. Models discussed for the fuzzy time series method include the Factor models, the Heuristic models, ... Keywords: ARIMA model, Fuzzy time series, Taiwan export

Chi-Chen Wang

2011-08-01T23:59:59.000Z

14

Investigating asymptotic properties of vector nonlinear time series models  

Science Conference Proceedings (OSTI)

Analyses and simulations of vector nonlinear time series typically run into weeks or even months because the methods used are computationally intensive. Statisticians have been known to base empirical results on a relatively small number of simulation ... Keywords: Dynamic loop scheduling, Vector FCAR models

Ioana Banicescu; Ricolindo L. CariO; Jane L. Harvill; John Patrick Lestrade

2011-09-01T23:59:59.000Z

15

Data Tools & Models - Time Series - U.S. Energy Information ...  

U.S. Energy Information Administration (EIA)

Time-series data for net generation, fossil fuel consumption for electricity generation, existing nameplate and net summer capacity, proposed nameplate capacity, ...

16

The Application of Time Series Models to Cloud Field Morphology Analysis  

Science Conference Proceedings (OSTI)

A modeling method for the quantitative description of remotely sensed cloud field images is presented. A two-dimensional texture modeling scheme based on one-dimensional time series procedures is adopted for this purpose. The time series ...

Roland T. Chin; Jack Y. C. Jau; James A. Weinman

1987-03-01T23:59:59.000Z

17

Regime-Dependent Autoregressive Time Series Modeling of the Southern Oscillation  

Science Conference Proceedings (OSTI)

The class of regime dependent autoregressive time series models (RAMs) is introduced. These nonlinear models describe variations of the moments of nonstationary time series by allowing parameter values to change with the state of an ancillary ...

Francis Zwiers; Hans Von Storch

1990-12-01T23:59:59.000Z

18

TaSe model for long term time series forecasting  

Science Conference Proceedings (OSTI)

There exists a wide range of paradigms and a high number of different methodologies applied to the problem of Time Series Prediction. Most of them are presented as a modified function approximation problem using I/O data, in which the input data is expanded ...

Luis Javier Herrera; Hctor Pomares; Ignacio Rojas; Alberto Guilln; Olga Valenzuela; Alberto Prieto

2005-06-01T23:59:59.000Z

19

Forecasting Financial Time-Series using Artificial Market Models  

E-Print Network (OSTI)

We discuss the theoretical machinery involved in predicting financial market movements using an artificial market model which has been trained on real financial data. This approach to market prediction - in particular, forecasting financial time-series by training a third-party or 'black box' game on the financial data itself -- was discussed by Johnson et al. in cond-mat/0105303 and cond-mat/0105258 and was based on some encouraging preliminary investigations of the dollar-yen exchange rate, various individual stocks, and stock market indices. However, the initial attempts lacked a clear formal methodology. Here we present a detailed methodology, using optimization techniques to build an estimate of the strategy distribution across the multi-trader population. In contrast to earlier attempts, we are able to present a systematic method for identifying 'pockets of predictability' in real-world markets. We find that as each pocket closes up, the black-box system needs to be 'reset' - which is equivalent to sayi...

Gupta, N; Johnson, N F; Gupta, Nachi; Hauser, Raphael; Johnson, Neil F.

2005-01-01T23:59:59.000Z

20

Stylized facts of financial time series and hidden semi-Markov models  

Science Conference Proceedings (OSTI)

Hidden Markov models reproduce most of the stylized facts about daily series of returns. A notable exception is the inability of the models to reproduce one ubiquitous feature of such time series, namely the slow decay in the autocorrelation function ... Keywords: Daily return series, EM algorithm, Hidden Markov model, Hidden semi-Markov model, Right-censoring, Sojourn time distribution

Jan Bulla; Ingo Bulla

2006-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "time series models" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

A hybrid neural network and ARIMA model for water quality time series prediction  

Science Conference Proceedings (OSTI)

Accurate predictions of time series data have motivated the researchers to develop innovative models for water resources management. Time series data often contain both linear and nonlinear patterns. Therefore, neither ARIMA nor neural networks can be ... Keywords: ARIMA, Backpropagation, Hybrid model, Neural networks, Time series

Durdu mer Faruk

2010-06-01T23:59:59.000Z

22

Multi-Scale Kernel Latent Variable Models for Nonlinear Time Series Pattern Matching  

Science Conference Proceedings (OSTI)

In this paper we propose a method for nonlinear time series pattern matching: "Multi-Scale Kernel Latent Variable (MSKLV) models". The pattern matching methodology includes multi-scale analysis using wavelet decomposition of time series and finding latent ...

B. Venkataramana Kini; C. Chandra Sekhar

2008-01-01T23:59:59.000Z

23

Univariate modeling and forecasting of monthly energy demand time series using abductive and neural networks  

Science Conference Proceedings (OSTI)

Neural networks have been widely used for short-term, and to a lesser degree medium and long-term, demand forecasting. In the majority of cases for the latter two applications, multivariate modeling was adopted, where the demand time series is related ... Keywords: Abductive networks, Energy demand, Medium-term load forecasting, Neural networks, Time series forecasting, Univariate time series analysis

R. E. Abdel-Aal

2008-05-01T23:59:59.000Z

24

Hybridization of intelligent techniques and ARIMA models for time series prediction  

Science Conference Proceedings (OSTI)

Traditionally, the autoregressive moving average (ARMA) model has been one of the most widely used linear models in time series prediction. Recent research activities in forecasting with artificial neural networks (ANNs) suggest that ANNs can be a promising ... Keywords: ARIMA models, Fuzzy systems, Hybrid system, Neural networks, Time series

O. Valenzuela; I. Rojas; F. Rojas; H. Pomares; L. J. Herrera; A. Guillen; L. Marquez; M. Pasadas

2008-04-01T23:59:59.000Z

25

Defining and applying prediction performance metrics on a recurrent NARX time series model  

Science Conference Proceedings (OSTI)

Nonlinear autoregressive moving average with exogenous inputs (NARMAX) models have been successfully demonstrated for modeling the input-output behavior of many complex systems. This paper deals with the proposition of a scheme to provide time series ... Keywords: NARX models, Prediction performance metrics, Recurrent radial basis function network, Time series prediction

Ryad Zemouri; Rafael Gouriveau; Noureddine Zerhouni

2010-08-01T23:59:59.000Z

26

Time Series and Forecasting  

Science Conference Proceedings (OSTI)

Time Series and Forecasting. Leigh, Stefan and Perlman, S. (1991). "An Index for Comovement of Time Sequences With ...

27

Identification of time series model of heat demand using mathematica environment  

Science Conference Proceedings (OSTI)

The paper presents possibility of model design of time series of heat demand course. The course of heat demand and heat consumption can be demonstrated by means of heat demand diagrams. The most important one is the Daily Diagram of Heat Supply (DDHS) ... Keywords: box-jenkins, control algorithms, district heating control, modelling, prediction, time series analysis

Bronislav Chramcov

2011-05-01T23:59:59.000Z

28

A novel hybridization of artificial neural networks and ARIMA models for time series forecasting  

Science Conference Proceedings (OSTI)

Improving forecasting especially time series forecasting accuracy is an important yet often difficult task facing decision makers in many areas. Both theoretical and empirical findings have indicated that integration of different models can be an effective ... Keywords: Artificial neural networks (ANNs), Auto-regressive integrated moving average (ARIMA), Hybrid models, Time series forecasting

Mehdi Khashei; Mehdi Bijari

2011-03-01T23:59:59.000Z

29

Application of Bayesian trained RBF networks to nonlinear time-series modeling  

Science Conference Proceedings (OSTI)

We examine Bayesian learning of a regularization factor and the noise level of radial basis function (RBF) networks in the framework of nonlinear time-series prediction and system modeling. A Bayesian trained RBF network is applied in an autonomous recursive ... Keywords: Bayesian learning, nonlinear modeling, oscillator model

Erhard Rank

2003-07-01T23:59:59.000Z

30

TIME SERIES MODELS OF THREE SETS OF RXTE OBSERVATIONS OF 4U 1543-47  

SciTech Connect

The X-ray nova 4U 1543-47 was in a different physical state (low/hard, high/soft, and very high) during the acquisition of each of the three time series analyzed in this paper. Standard time series models of the autoregressive moving average (ARMA) family are fitted to these series. The low/hard data can be adequately modeled by a simple low-order model with fixed coefficients, once the slowly varying mean count rate has been accounted for. The high/soft series requires a higher order model, or an ARMA model with variable coefficients. The very high state is characterized by a succession of 'dips', with roughly equal depths. These seem to appear independently of one another. The underlying stochastic series can again be modeled by an ARMA form, or roughly as the sum of an ARMA series and white noise. The structuring of each model in terms of short-lived aperiodic and 'quasi-periodic' components is discussed.

Koen, C. [Department of Statistics, University of the Western Cape, Private Bag X17, Bellville, 7535 Cape (South Africa)] [Department of Statistics, University of the Western Cape, Private Bag X17, Bellville, 7535 Cape (South Africa)

2013-03-01T23:59:59.000Z

31

Automatic Detection of Geomagnetic Jerks by Applying a Statistical Time Series Model  

E-Print Network (OSTI)

Automatic Detection of Geomagnetic Jerks by Applying a Statistical Time Series Model to Geomagnetic@ism.ac.jp 3 Data Analysis Center for Geomagnetism and Space Magnetism, Graduate School of Science, Kyoto. A geomagnetic jerk is de#12;ned as a sudden change in the trend of the time derivative of geomagnetic secular

Higuchi, Tomoyuki

32

Time Series Forecasting for Dynamic Environments: the DyFor Genetic Program Model  

E-Print Network (OSTI)

Time Series Forecasting for Dynamic Environments: the DyFor Genetic Program Model Neal Wagner programming (GP) to the task of forecasting with favorable results. However, these studies, like those "dynamic" GP model that is specifically tailored for forecasting in non-static environments. This Dynamic

Michalewicz, Zbigniew

33

An emission time series generator for pollutant release modelling in urban areas  

Science Conference Proceedings (OSTI)

Dynamic priority pollutant (PP) fate models are being developed to assess appropriate strategies for limiting the release of PPs from urban sources and for treating PPs on a variety of spatial scales. Different possible sources of PP releases were mapped ... Keywords: Emission pattern, Generator, Priority pollutants, Release dynamics, Sewer catchment model, Time series

W. De Keyser; V. Gevaert; F. Verdonck; B. De Baets; L. Benedetti

2010-04-01T23:59:59.000Z

34

Forecasting airborne pollen concentration time series with neural and neuro-fuzzy models  

Science Conference Proceedings (OSTI)

Forecasting airborne pollen concentrations is one of the most studied topics in aerobiology, due to its crucial application to allergology. The most used tools for this problem are single lineal regressions and autoregressive models (ARIMA). Notwithstanding, ... Keywords: Aerobiology, Airborne pollen, Forecasting, Neuro-fuzzy, Time series

Jos Luis Aznarte M.; Jos Manuel Bentez Snchez; Diego Nieto Lugilde; Concepcin de Linares Fernndez; Consuelo Daz de la Guardia; Francisca Alba Snchez

2007-05-01T23:59:59.000Z

35

Characterizing forest fire activity in Turkey by compound Poisson and time series models  

Science Conference Proceedings (OSTI)

Large forest fires are major disturbances that strongly influence the carbon cycling and vegetation dynamics of Turkish ecosystems. We suggest that compound Poisson model could provide suitable description for the total annual area burned by forest fires and for fire size distribution in Turkey. This paper also provides a time series model that reveals trends in annual number of fires and area burned in Turkey. We support this argument using forest fires occurred in Turkey between 1937 and 2009. We also find that the Poisson model simulates large fire occurrences well and the total burned area is modeled by a compound Poisson process.

Hatice . ekim; Cem Kad?lar; Gamze zel

2013-01-01T23:59:59.000Z

36

Time-series models with many discrete alternatives. CONF-8309138--1  

SciTech Connect

In process and inventory control, time-series models occur with discrete alternatives in each time period (e.g., in an inventory process, the alternatives of no loss, or a block loss, in each period). With such a model, a fully Bayesian approach requires that the number of possible alternatives increase geometrically with time. In this paper, the problem of discarding the large set of alternatives which turn out to be (on the basis of the data) wildly unlikely is discussed from a fully Bayesian viewpoint. Costs of computation are compared with two sources of costs of truncating the model. Algorithms are given for the selection of the set of alternatives to retain. Simplified guidelines for practical situations are given.

Durst, M.

1983-08-01T23:59:59.000Z

37

Design of specific-to-problem kernels and use of kernel weighted K-nearest neighbours for time series modelling  

Science Conference Proceedings (OSTI)

Least squares support vector machines (LSSVM) with Gaussian kernel represent the most used of the kernel methods existing in the literature for regression and time series prediction. These models have a good behaviour for these types of problems due ... Keywords: Kernel methods, Kernel weighted K-Nearest Neighbours, Least squares support vector machines, Parallelization of kernel methods, Specific to problem kernels, Time series modelling

Gins Rubio; Luis Javier Herrera; Hctor Pomares; Ignacio Rojas; Alberto Guilln

2010-06-01T23:59:59.000Z

38

Point and Interval Forecasting of Spot Electricity Prices: Linear vs. Non-Linear Time Series Models  

E-Print Network (OSTI)

In this paper we assess the short-term forecasting power of different time series models in the electricity spot market. In particular we calibrate AR/ARX (X stands for exogenous/fundamental variable system load in our study), AR/ARX-GARCH, TAR/TARX and Markov regime-switching models to California Power Exchange (CalPX) system spot prices. We then use them for out-ofsample point and interval forecasting in normal and extremely volatile periods preceding the market crash in winter 2000/2001. We find evidence that (i) non-linear, threshold regime-switching (TAR/TARX) models outperform their linear counterparts, both in point and interval forecasting, and that (ii) an additional GARCH component generally decreases point forecasting efficiency. Interestingly, the former result challenges a number of previously published studies on the failure of non-linear regime-switching models in forecasting.

Adam Misiorek; Stefan Trueck; Rafal Weron

2006-01-01T23:59:59.000Z

39

EOFs of One-Dimensional Cyclostationary Time Series: Computations, Examples, and Stochastic Modeling  

Science Conference Proceedings (OSTI)

Many climatic time series seem to be a mixture of unpredictable fluctuations and changes that occur at a known frequency, as in the case of the annual cycle. Such a time series is called a cyclostationary process. The lagged covariance statistics ...

Kwang-Y. Kim; Gerald R. North; Jianping Huang

1996-04-01T23:59:59.000Z

40

Climatological Time Series with Periodic Correlation  

Science Conference Proceedings (OSTI)

Many climatological time series display a periodic correlation structure. This paper examines three issues encountered when analyzing such time series: detection of periodic correlation, modeling periodic correlation, and trend estimation under ...

Robert Lund; Harry Hurd; Peter Bloomfield; Richard Smith

1995-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "time series models" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Similarity retrieval from time-series tropical cyclone observations using a neural weighting generator for forecasting modeling  

Science Conference Proceedings (OSTI)

Building a forecasting model for time-series data is a tough but very valuable research topic in recent years. High variation of time-series features must be considered appropriately for an accurate prediction. For weather forecasting, which is continuous, ...

Bo Feng; James N. K. Liu

2005-09-01T23:59:59.000Z

42

Multi-horizon solar radiation forecasting for Mediterranean locations using time series models  

E-Print Network (OSTI)

Considering the grid manager's point of view, needs in terms of prediction of intermittent energy like the photovoltaic resource can be distinguished according to the considered horizon: following days (d+1, d+2 and d+3), next day by hourly step (h+24), next hour (h+1) and next few minutes (m+5 e.g.). Through this work, we have identified methodologies using time series models for the prediction horizon of global radiation and photovoltaic power. What we present here is a comparison of different predictors developed and tested to propose a hierarchy. For horizons d+1 and h+1, without advanced ad hoc time series pre-processing (stationarity) we find it is not easy to differentiate between autoregressive moving average (ARMA) and multilayer perceptron (MLP). However we observed that using exogenous variables improves significantly the results for MLP . We have shown that the MLP were more adapted for horizons h+24 and m+5. In summary, our results are complementary and improve the existing prediction techniques ...

Voyant, Cyril; Muselli, Marc; Nivet, Marie Laure

2013-01-01T23:59:59.000Z

43

Kernel Auto-Regressive Model with eXogenous Inputs for Nonlinear Time Series Prediction  

Science Conference Proceedings (OSTI)

In this paper we present a novel approach for nonlinear time series prediction using Kernel methods. The kernel methods such as Support Vector Machine(SVM) and Support Vector Regression(SVR) deal with nonlinear problems assuming independent and identically ...

Venkataramana B. Kini; C. Chandra Sekhar

2007-03-01T23:59:59.000Z

44

HYBRID GREY RELATIONAL ARTIFICIAL NEURAL NETWORK AND AUTO REGRESSIVE INTEGRATED MOVING AVERAGE MODEL FOR FORECASTING TIME-SERIES DATA  

Science Conference Proceedings (OSTI)

The aim of this study is to develop a new hybrid model by combining a linear and nonlinear model for forecasting time-series data. The proposed model (GRANN_ARIMA) integrates nonlinear grey relational artificial neural network (GRANN) and a linear autoregressive ...

Roselina Sallehuddin; Siti Mariyam Hj. Shamsuddin

2009-05-01T23:59:59.000Z

45

VBR MPEG Video Traffic Dynamic Prediction Based on the Modeling and Forecast of Time Series  

Science Conference Proceedings (OSTI)

The variable-bit-rate traffic characteristic brings a large complication to the utilization of network resources, especially bandwidth. To solve this problem, this paper proposes a dynamic prediction scheme of MPEG video traffic. We first advance an ... Keywords: MPEG, video trace, forecast, time series, ARMA

Jun Dai; Jun Li

2009-08-01T23:59:59.000Z

46

Forecasting of Chaotic Cloud Absorption Time Series for Meteorological and Plume Dispersion Modeling  

Science Conference Proceedings (OSTI)

A nonlinear forecasting method based on the reconstruction of a chaotic strange attractor from about 1.5 years of cloud absorption data obtained from half-hourly Meteosat infrared images was used to predict the behavior of the time series 24 h in ...

V. Prez-Muuzuri

1998-11-01T23:59:59.000Z

47

Predicting time series with advanced hybrid systems  

Science Conference Proceedings (OSTI)

Autogressive moving average (ARMA) has been widely used to model processes that generate linear time-series. Recent research activities in forecasting with artificial neutral networks (ANNs) suggest that ANNs can be a promising alternative to the traditional ... Keywords: ARMA models, fuzzy system, hybrid system, neutral networks, time series

O. Valenzuela; I. Rojas; F. Rojas; H. Pomares; J. Gonzalez; L. J. Herrera; A. Guillen

2005-12-01T23:59:59.000Z

48

Essays on empirical time series modeling with causality and structural change  

E-Print Network (OSTI)

In this dissertation, three related issues of building empirical time series models for financial markets are investigated with respect to contemporaneous causality, dynamics, and structural change. In the first essay, nation-wide industry information transmission among stock returns of ten sectors in the U.S. economy is examined through the Directed Acyclical Graph (DAG) for contemporaneous causality and Bernanke decomposition for dynamics. The evidence shows that the information technology sector is the most root cause sector. Test results show that DAG from ex ante forecast innovations is consistent with the DAG fro m ex post fit innovations. This supports innovation accounting based on DAGs using ex post innovations. In the second essay, the contemporaneous/dynamic behaviors of real estate and stock returns are investigated. Selected macroeconomic variables are included in the model to explain recent movements of both returns. During 1971-2004, there was a single structural break in October 1980. A distinct difference in contemporaneous causal structure before and after the break is found. DAG results show that REITs take the role of a causal parent after the break. Innovation accounting shows significantly positive responses of real estate returns due to an initial shock in default risk but insignificant responses of stock returns. Also, a shock in short run interest rates affects real estate returns negatively with significance but does not affect stock returns. In the third essay, a structural change in the volatility of five Asian and U.S. stock markets is examined during the post-liberalization period (1990-2005) in the Asian financial markets, using the Sup LM test. Four Asian financial markets (Hong Kong, Japan, Korea, and Singapore) experienced structural changes. However, test results do not support the existence of structural change in volatility for Thailand and U.S. Also, results show that the Generalized Autoregressive Conditional Heteroskedasticity (GARCH) persistent coefficient increases, but the Autoregressive Conditional heteroskedasticity (ARCH) impact coefficient, implying short run adjustment, decreases in Asian markets. In conclusion, when the econometric model is set up, it is necessary to consider contemporaneous causality and possible structural breaks (changes). The dissertation emphasizes causal inference and structural consistency in econometric modeling. It highlights their importance in discovering contemporaneous/dynamic causal relationships among variables. These characteristics will likely be helpful in generating accurate forecasts.

Kim, Jin Woong

2006-08-01T23:59:59.000Z

49

Time series forecasting with Qubit Neural Networks  

Science Conference Proceedings (OSTI)

This paper proposes a quantum learning scheme approach for time series forecasting, through the application of the new non-standard Qubit Neural Network (QNN) model. The QNN description was adapted in this work in order to resemble classical Artificial ... Keywords: artificial intelligence, artificial neural networks, quantum computing, qubit neural networks, time series forecasting

Carlos R. B. Azevedo; Tiago A. E. Ferreira

2007-08-01T23:59:59.000Z

50

Statistical criteria for characterizing irradiance time series.  

SciTech Connect

We propose and examine several statistical criteria for characterizing time series of solar irradiance. Time series of irradiance are used in analyses that seek to quantify the performance of photovoltaic (PV) power systems over time. Time series of irradiance are either measured or are simulated using models. Simulations of irradiance are often calibrated to or generated from statistics for observed irradiance and simulations are validated by comparing the simulation output to the observed irradiance. Criteria used in this comparison should derive from the context of the analyses in which the simulated irradiance is to be used. We examine three statistics that characterize time series and their use as criteria for comparing time series. We demonstrate these statistics using observed irradiance data recorded in August 2007 in Las Vegas, Nevada, and in June 2009 in Albuquerque, New Mexico.

Stein, Joshua S.; Ellis, Abraham; Hansen, Clifford W.

2010-10-01T23:59:59.000Z

51

Identification of Models for Some Times Series of Atmospheric Origin with Akaike's Information Criterion  

Science Conference Proceedings (OSTI)

Akaike's method for model identification has been used to identify Markov chain models for simple transformations of daily precipitation at three locations in southern Norway, and wind force and wave height at one location in the Norwegian Sea. ...

Karl J. Eidsvik

1980-04-01T23:59:59.000Z

52

Modeling the Contribution of the Brussels Heat Island to a Long Temperature Time Series  

Science Conference Proceedings (OSTI)

A mesoscale meteorological model containing a detailed land surface model is used to assess the contribution of urban heating to the temperature record of the national recording station of Belgium in Uccle, near Brussels. The Advanced Regional ...

K. Van Weverberg; K. De Ridder; A. Van Rompaey

2008-04-01T23:59:59.000Z

53

Time series analysis of a Web search engine transaction log  

Science Conference Proceedings (OSTI)

In this paper, we use time series analysis to evaluate predictive scenarios using search engine transactional logs. Our goal is to develop models for the analysis of searchers' behaviors over time and investigate if time series analysis is a valid method ... Keywords: ARIMA, Box-Jenkins model, Search engine, Time series analysis, Transactional log

Ying Zhang; Bernard J. Jansen; Amanda Spink

2009-03-01T23:59:59.000Z

54

A review on time series data mining  

Science Conference Proceedings (OSTI)

Time series is an important class of temporal data objects and it can be easily obtained from scientific and financial applications. A time series is a collection of observations made chronologically. The nature of time series data includes: large in ... Keywords: Representation, Segmentation, Similarity measure, Time series data mining, Visualization

Tak-chung Fu

2011-02-01T23:59:59.000Z

55

Deterministic regression model and visual basic code for optimal forecasting of financial time series  

Science Conference Proceedings (OSTI)

A new, non-statistical method is presented for analysis of the past history and current evolution of economic and financial processes. The method is based on the sliding model approach using linear differential or difference equations applied to discrete ... Keywords: Optimal forecasting in finance, Sliding deterministic regression models

Alejandro Balbs; Beatriz Balbs; Inna Galperin; Efim Galperin

2008-11-01T23:59:59.000Z

56

Time Series Models to Simulate and Forecast Wind Speed and Wind Power  

Science Conference Proceedings (OSTI)

A general approach for modeling wind speed and wind power is described. Because wind power is a function of wind speed, the methodology is based on the development of a model of wind speed. Values of wind power are estimated by applying the ...

Barbara G. Brown; Richard W. Katz; Allan H. Murphy

1984-08-01T23:59:59.000Z

57

A supply forecasting model for Zimbabwe's corn sector: a time series and structural analysis  

E-Print Network (OSTI)

The Zimbabwean government utilizes the corn supply forecasts to establish producer prices for the following growing season, estimate corn storage and handling costs, project corn import needs and associated costs, and to assess the Grain Marketing Board's financial resource needs. Thus, the corn supply forecasts are important information used by the government for contingency planning, decision-making, policy-formulation and implementation. As such, the need for accurate forecasts is obvious. The objectives of the study are: (a) determine how changes in the government-established producer price affects the quantity of corn supplied to the Grain Marketing Board by the large-scale corn-producing sector and (b) whether including rainfall or rainfall probabilities into econometric models would result in an improvement of corn supply forecasts compared to current forecasts by the government. In order to accomplish the first objective a supply elasticity model was specified and estimated using ordinary least squares. This model is intended to provide 'de insight to the government regarding the influence of the government-established corn price and other related variables on corn supplied to the Grain Marketing Board by the large-scale producers. Thus, the estimated model would be useful to the government when establishing corn prices in March/April for production in the following growing season (October - February). To achieve the second objective, preliminary analysis was carried out to verify whether there is statistical evidence to support the hypothesis that rainfall cause" corn production and supply, and also corn prices and sales. Specifically the preliminary analysis involved using the Granger causality tests, stationarity tests and innovation accounting (impulse responses and forecast error decomposition). Having verified and quantified the causal effects of rainfall on corn production and supply, the next task was to investigate whether including rainfall and/or drought probabilities into forecasting econometric models would help provide improved out-of-sample forecasts compared to the government's forecasts. The forecasting accuracy of the models (short-run) was evaluated using standard statistical measures such as, the mean square error (MSE), mean absolute percentage error (MAPEI), improved mean absolute percentage error (IMAPE) and Theil's U-statistic, and thereupon select the best model. The results indicated that by incorporating rainfall and/or rainfall probabilities into econometric forecasting models, there was substantial improvement in corn supply forecasts. It follows that the the government would likely find it beneficial to incorporate the rainfall variable into their forecasting effort.

Makaudze, Ephias

1993-01-01T23:59:59.000Z

58

Temporal Resolution in Time Series and Probabilistic Models of Renewable Power Eric Hoevenaars  

E-Print Network (OSTI)

LPSP loss of power supply probability MPPT maximum power point tracker NOCT nominal operating cell of the wind turbine is often interpolated from the tur- bine's power curve. This curve can be obtained feedback controller A dynamic model was created in Simulink with variable speed Cp and stall control

Victoria, University of

59

Segmenting Time Series for Weather Forecasting  

E-Print Network (OSTI)

turbines. In the domain of meteorology, time series data produced by numerical weather prediction (NWP) models is summarised as weather forecast texts. In the domain of gas turbines, sensor data from an operational gas turbine is summarised for the maintenance engineers. More details on SUMTIME have been

Reiter, Ehud

60

TIME SERIES MODELING  

Science Conference Proceedings (OSTI)

does involve some knowledge of hydrodynamics (especially when decid- ing the formula for ... 109120. Munk, W.H., and Cartwright, D.E., 1966. Tidal spectroscopy and pre- diction. ..... Principles of Forecasting: A Handbook for. Researchers...

Note: This page contains sample records for the topic "time series models" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Beyond long memory in heart rate variability: An approach based on fractionally integrated autoregressive moving average time series models with conditional heteroscedasticity  

Science Conference Proceedings (OSTI)

Heart Rate Variability (HRV) series exhibit long memory and time-varying conditional variance. This work considers the Fractionally Integrated AutoRegressive Moving Average (ARFIMA) models with Generalized AutoRegressive Conditional Heteroscedastic (GARCH) errors. ARFIMA-GARCH models may be used to capture and remove long memory and estimate the conditional volatility in 24 h HRV recordings. The ARFIMA-GARCH approach is applied to fifteen long term HRV series available at Physionet

2013-01-01T23:59:59.000Z

62

Time Series Dependent Analysis of Unparametrized Thomas Networks  

Science Conference Proceedings (OSTI)

This paper is concerned with the analysis of labeled Thomas networks using discrete time series. It focuses on refining the given edge labels and on assessing the data quality. The results are aimed at being exploitable for experimental design and include ... Keywords: Time series analysis,Regulators,Computational modeling,Time measurement,Bioinformatics,Computational biology,Labeling,constraint satisfaction.,Time series analysis,model checking,temporal logic,biology and genetics

Hannes Klarner; Heike Siebert; Alexander Bockmayr

2012-09-01T23:59:59.000Z

63

Time Series Prediction Forecasting the Future and ...  

Science Conference Proceedings (OSTI)

Time Series Prediction Forecasting the Future and Understanding the Past Santa Fe Institute Proceedings on the Studies in the Sciences of ...

2012-10-01T23:59:59.000Z

64

Efficient forecasting for hierarchical time series  

Science Conference Proceedings (OSTI)

Forecasting is used as the basis for business planning in many application areas such as energy, sales and traffic management. Time series data used in these areas is often hierarchically organized and thus, aggregated along the hierarchy levels based ... Keywords: forecasting, hierarchies, optimization, time series

Lars Dannecker; Robert Lorenz; Philipp Rsch; Wolfgang Lehner; Gregor Hackenbroich

2013-10-01T23:59:59.000Z

65

Parametric spectral analysis of malaria gene expression time series data  

Science Conference Proceedings (OSTI)

Spectral analysis of DNA microarray gene expressions time series data is important for understanding the regulation of gene expression and gene function of the Plasmodium falciparum in the intraerythrocytic developmental cycle. In this paper, ... Keywords: autoregressive model, microarray time series analysis, plasmodium falciparum, singular spectrum analysis, spectral estimation

Liping Du; Shuanhu Wu; Alan Wee-Chung Liew; David Keith Smith; Hong Yan

2006-09-01T23:59:59.000Z

66

Time Series Analysis and Forecasting in Stock Market Investments  

E-Print Network (OSTI)

Time Series Analysis and Forecasting in Stock Market Investments Ted Chi-Wei Fung Department and forecasting have been used as methods to help precisely on the task of stock market prediction by using past data. This paper will discuss three different models to create a time series analysis and forecast

Zanibbi, Richard

67

Tritium Time Series from Ocean Station P  

Science Conference Proceedings (OSTI)

We present time series of tritium (3H) concentrations at varying depths in the water column at Ocean Station P(50N, 145W) in the northeast Pacific. Measurements started in the fall of 1974, at the time of the GEOSECS mapping of the North ...

A. E. Gargett; G. Ostlund; C. S. Wong

1986-10-01T23:59:59.000Z

68

Integrated method for chaotic time series analysis  

DOE Patents (OSTI)

Methods and apparatus for automatically detecting differences between similar but different states in a nonlinear process monitor nonlinear data. Steps include: acquiring the data; digitizing the data; obtaining nonlinear measures of the data via chaotic time series analysis; obtaining time serial trends in the nonlinear measures; and determining by comparison whether differences between similar but different states are indicated.

Hively, Lee M. (Philadelphia, TN); Ng, Esmond G. (Concord, TN)

1998-01-01T23:59:59.000Z

69

Integrated method for chaotic time series analysis  

DOE Patents (OSTI)

Methods and apparatus for automatically detecting differences between similar but different states in a nonlinear process monitor nonlinear data are disclosed. Steps include: acquiring the data; digitizing the data; obtaining nonlinear measures of the data via chaotic time series analysis; obtaining time serial trends in the nonlinear measures; and determining by comparison whether differences between similar but different states are indicated. 8 figs.

Hively, L.M.; Ng, E.G.

1998-09-29T23:59:59.000Z

70

Can biomass time series be reliably assessed from CPUE time series data Francis Lalo1  

E-Print Network (OSTI)

1 Can biomass time series be reliably assessed from CPUE time series data only? Francis Laloë1 to abundance. This means (i) that catchability is constant and (ii) that all the biomass is catchable. If so, relative variations in CPUE indicate the same relative variations in biomass. Myers and Worm consider

Hawai'i at Manoa, University of

71

Generation of an Hourly Meteorological Time Series for an Alpine Basin in British Columbia for Use in Numerical Hydrologic Modeling  

Science Conference Proceedings (OSTI)

Spatially distributed numerical hydrologic models are useful tools for examining the long-term impact of forest harvesting in mountainous basins on streamflow regime properties. Such models require the input of long-duration subdaily ...

Markus Schnorbus; Younes Alila

2004-10-01T23:59:59.000Z

72

A hybrid model of self-organizing maps (SOM) and least square support vector machine (LSSVM) for time-series forecasting  

Science Conference Proceedings (OSTI)

Support vector machine is a new tool from Artificial Intelligence (AI) field has been successfully applied for a wide variety of problem especially in time-series forecasting. In this paper, least square support vector machine (LSSVM) is an improved ... Keywords: Forecasting, Least square support vector machine, Self-organizing maps, Time series

Shuhaida Ismail; Ani Shabri; Ruhaidah Samsudin

2011-08-01T23:59:59.000Z

73

Extracting biochemical reaction kinetics from time series data  

E-Print Network (OSTI)

Abstract. We consider the problem of inferring kinetic mechanisms for biochemical reactions from time series data. Using a priori knowledge about the structure of chemical reaction kinetics we develop global nonlinear models which use elementary reactions as a basis set, and discuss model construction using top-down and bottom-up approaches. 1

Edmund J. Crampin; Patrick E. Mcsharry; Santiago Schnell

2004-01-01T23:59:59.000Z

74

Combining motif information and neural network for time series prediction  

Science Conference Proceedings (OSTI)

Recent research works pay more attention to time series prediction, in which some time series data mining approaches have been exploited. In this paper, we propose a new method for time series prediction which is based on the concept of time series motifs. ...

Cao Duy Truong; Huynh Nguyen Tin; Duong Tuan Anh

2012-01-01T23:59:59.000Z

75

Improved forecasting of time series data of real system using genetic programming  

Science Conference Proceedings (OSTI)

A study is made to improve short term forecasting of time series data of real system using Genetic Programming (GP) under the framework of time delayed embedding technique. GP based approach is used to make analytical model of time series data of real ... Keywords: genetic programming, state-space reconstruction, time series forecasting

Dilip P. Ahalpara

2010-07-01T23:59:59.000Z

76

IMPROVEMENTS TO THE RADIANT TIME SERIES METHOD COOLING LOAD CALCULATION  

E-Print Network (OSTI)

IMPROVEMENTS TO THE RADIANT TIME SERIES METHOD COOLING LOAD CALCULATION PROCEDURE By BEREKET TO THE RADIANT TIME SERIES METHOD COOLING LOAD CALCULATION PROCEDURE Dissertation Approved: Dr. Jeffrey D- Original RTSM.......................................................153 4.4.1 RTSM Peak Design Cooling Load

77

Changepoint Detection in Periodic and Autocorrelated Time Series  

Science Conference Proceedings (OSTI)

Undocumented changepoints (inhomogeneities) are ubiquitous features of climatic time series. Level shifts in time series caused by changepoints confound many inference problems and are very important data features. Tests for undocumented ...

Robert Lund; Xiaolan L. Wang; Qi Qi Lu; Jaxk Reeves; Colin Gallagher; Yang Feng

2007-10-01T23:59:59.000Z

78

A New Method for Time Series Filtering near Endpoints  

Science Conference Proceedings (OSTI)

Time series filtering (e.g., smoothing) can be done in the spectral domain without loss of endpoints. However, filtering is commonly performed in the time domain using convolutions, resulting in lost points near the series endpoints. Multiple ...

Anthony Arguez; Peng Yu; James J. OBrien

2008-04-01T23:59:59.000Z

79

Detecting and Classifying Events in Noisy Time Series  

Science Conference Proceedings (OSTI)

Time series are characterized by a myriad of different shapes and structures. A number of events that appear in atmospheric time series result from as yet unidentified physical mechanisms. This is particularly the case for stable boundary layers, ...

Yanfei Kang; Danijel Belui?; Kate Smith-Miles

80

Bispectral-based methods for clustering time series  

Science Conference Proceedings (OSTI)

Distinguishing among linear and nonlinear time series or between nonlinear time series generated by different underlying processes is challenging, as second-order properties are generally insufficient for the task. Different nonlinear processes have ... Keywords: Bispectral density function, Hierarchical clustering, Nonlinear time series

Jane L. Harvill, Nalini Ravishanker, Bonnie K. Ray

2013-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "time series models" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Feature-based clustering for electricity use time series data  

Science Conference Proceedings (OSTI)

Time series clustering has been shown effective in providing useful information in various applications. This paper presents an efficient computational method for time series clustering and its application focusing creation of more accurate electricity ... Keywords: electricity distribution, electricity use data, feature extraction, feature-based clustering, load curves, time series clustering

Teemu Rsnen; Mikko Kolehmainen

2009-04-01T23:59:59.000Z

82

Optimizing the extreme learning machine using harmony search for hydrologic time series forecasting  

Science Conference Proceedings (OSTI)

Lately, the research related to time series forecasting has been an area of considerable interest in different fields. It is very important to predict the behavior of the time series but it is not an easy task. Several models to aim this issue have been ... Keywords: extreme learning machine, harmony search, hybrid intelligent system, time series forecasting

Ivna Valena; Muser Valena

2012-08-01T23:59:59.000Z

83

An Approach to Adjusting Climatological Time Series for Discontinuous Inhomogeneities  

Science Conference Proceedings (OSTI)

A method is described whereby climatological time series of temperature and precipitation can be adjusted for station inhomogeneities using station history information. The adjusted data retains its original scale and is not an anomaly series. ...

Thomas R. Karl; Claude N. Williams Jr.

1987-12-01T23:59:59.000Z

84

Long-term time series prediction with the NARX network: An empirical evaluation  

Science Conference Proceedings (OSTI)

The NARX network is a dynamical neural architecture commonly used for input-output modeling of nonlinear dynamical systems. When applied to time series prediction, the NARX network is designed as a feedforward time delay neural network (TDNN), i.e., ... Keywords: Chaotic time series, Long-term prediction, NARX neural network, Nonlinear traffic modeling, Recurrence plot

Jos Maria P. Menezes, Jr.; Guilherme A. Barreto

2008-10-01T23:59:59.000Z

85

Comparing statistical and neural network approaches for urban air pollution time series analysis  

Science Conference Proceedings (OSTI)

The paper presents an analysis of the performances obtained by using an artificial neural networks model and several statistical models for urban air quality forecasting. The time series of monthly averages concentrations (Sedimentable Dusts, Total Suspended ... Keywords: ARIMA, back-propagation, feed-forward neural network, statistical models, time series, urban air quality

Daniel Dunea; Mihaela Oprea; Emil Lungu

2008-02-01T23:59:59.000Z

86

Spectral estimation for locally stationary time series with missing observations  

Science Conference Proceedings (OSTI)

Time series arising in practice often have an inherently irregular sampling structure or missing values, that can arise for example due to a faulty measuring device or complex time-dependent nature. Spectral decomposition of time series is a traditionally ... Keywords: Missing data, Nondecimated transform, Spectral estimation, Wavelet lifting

Marina I. Knight; Matthew A. Nunes; Guy P. Nason

2012-07-01T23:59:59.000Z

87

Characterizability of metabolic pathway systems from time series...  

NLE Websites -- All DOE Office Websites (Extended Search)

Characterizability of metabolic pathway systems from time series data Eberhard O. Voit The Wallace H. Coulter, Department of Biomedical Engineering at Georgia Tech. and Emory...

88

Time Series Graphs of Global and Hemispheric Temperature Anomalies...  

NLE Websites -- All DOE Office Websites (Extended Search)

Time Series Graphs of Global and Hemispheric Temperature Anomalies graphics Graph - Global and Hemispheric Annual Temperature Anomalies, 1850-2012 graphics Graph - Northern...

89

A Study on Training Criteria for Financial Time Series Forecasting  

E-Print Network (OSTI)

A Study on Training Criteria for Financial Time Series Forecasting JingTao YAO Dept of Information on goodness-of-fit which is also the most popular criterion forecasting. How ever, in the context of financial time series forecasting, we are not only concerned at how good the forecasts fit their target. In order

Yao, JingTao

90

Short term wind power forecasting using time series neural networks  

Science Conference Proceedings (OSTI)

Forecasting wind power energy is very important issue in a liberalized market and the prediction tools can make wind energy be competitive in these kinds of markets. This paper will study an application of time-series and neural network for predicting ... Keywords: neural networks, time series, wind power forecasting

Mohammadsaleh Zakerinia; Seyed Farid Ghaderi

2011-04-01T23:59:59.000Z

91

Time Series Momentum Trading Strategy and Autocorrelation Amplification  

E-Print Network (OSTI)

Time Series Momentum Trading Strategy and Autocorrelation Amplification K. J. Hong and S. Satchell June 2013 CWPE 1322 1 Time Series Momentum Trading Strategy and Autocorrelation Amplification... K. J. Honga,* and S. Satchellb Current Version: May 23, 2013 a University Technology of Sydney, Ultimo Rd, Haymarket NSW 2000, Australia b Trinity College, University of Cambridge, Address: Trinity College, Cambridge, CB2 1TQ, U...

Hong, K. J.; Satchell, S.

2013-06-18T23:59:59.000Z

92

Comparing non-stationary and irregularly spaced time series  

Science Conference Proceedings (OSTI)

In this paper, we present approximate distributions for the ratio of the cumulative wavelet periodograms considering stationary and non-stationary time series generated from independent Gaussian processes. We also adapt an existing procedure to use this ... Keywords: Distributions of quadratic forms, Hypothesis testing, Irregularly spaced time series, Locally stationary wavelet processes, Multiresolution approximation

Gladys E. Salcedo; RogRio F. Porto; Pedro A. Morettin

2012-12-01T23:59:59.000Z

93

Analysis of Long Time Series of Coastal Wind  

Science Conference Proceedings (OSTI)

A study of a 14-yr time series of wind speed recorded on the coast outside the city of Trondheim in middle Norway is presented. Analysis of the time series shows that in this area there is, in general, no gap in the wind speed power spectrum in ...

Tore Heggem; Rune Lende; Jrgen Lvseth

1998-09-01T23:59:59.000Z

94

A liquidity-weighted GARCH model for empirical equity series  

Science Conference Proceedings (OSTI)

This paper develops a new GARCH-family model (named Liquidity-Weighted GARCH or LW-GARCH) for explaining the volatility behaviour of financial time series, with an application on empirical international equity series (consisting both of stock market ... Keywords: ARCH-LM test, Granger causality test, conditional volatility, empirical equity returns, liquidity-weighted GARCH

Cristiana Tudor

2011-07-01T23:59:59.000Z

95

Hypothesis testing for auto-correlated short climate time series  

Science Conference Proceedings (OSTI)

Commonly used statistical tests of hypothesis, also termed inferential tests, which are available to meteorologists and climatologists all require independent data in the time series to which they are applied. Unfortunately, most of the time ...

Virginie Guemas; Ludovic Auger; Francisco J. Doblas-Reyes

96

Different Approaches to Forecast Interval Time Series: A Comparison in Finance  

Science Conference Proceedings (OSTI)

An interval time series (ITS) is a time series where each period is described by an interval. In finance, ITS can describe the temporal evolution of the high and low prices of an asset throughout time. These price intervals are related to the concept ... Keywords: Artificial neural networks, Exponential smoothing, Interval arithmetic, Interval data, Nearest neighbors methods, Vector autoregressive models

Javier Arroyo; Rosa Espnola; Carlos Mat

2011-02-01T23:59:59.000Z

97

A new time-invariant fuzzy time series forecasting method based on genetic algorithm  

Science Conference Proceedings (OSTI)

In recent years, many fuzzy time series methods have been proposed in the literature. Some of these methods use the classical fuzzy set theory, which needs complex matricial operations in fuzzy time series methods. Because of this problem, many studies ...

Erol E?rio?lu

2012-01-01T23:59:59.000Z

98

Approximate k-NN delta test minimization method using genetic algorithms: Application to time series  

Science Conference Proceedings (OSTI)

In many real world problems, the existence of irrelevant input variables (features) hinders the predictive quality of the models used to estimate the output variables. In particular, time series prediction often involves building large regressors of ... Keywords: Approximate k-nearest neighbors, Delta test, Genetic algorithm, Time series, Variable projection, Variable scaling, Variable selection

Fernando Mateo; Duan Sovilj; Rafael Gadea

2010-06-01T23:59:59.000Z

99

Homogenization of Radiosonde Temperature Time Series Using Innovation Statistics  

Science Conference Proceedings (OSTI)

Radiosonde temperature records contain valuable information for climate change research from the 1940s onward. Since they are affected by numerous artificial shifts, time series homogenization efforts are required. This paper introduces a new ...

Leopold Haimberger

2007-04-01T23:59:59.000Z

100

Generating Scenarios of Local Surface Temperature Using Time Series Methods  

Science Conference Proceedings (OSTI)

A method for creating scenarios of time series of monthly mean surface temperature at a specific site is developed. It is postulated that surface temperature can be specified as a linear combination of regional and local temperature components, ...

Robert S. Chen; Peter J. Robinson

1991-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "time series models" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Eyeballing Trends in Climate Time Series: A Cautionary Note  

Science Conference Proceedings (OSTI)

In examining a plot of a time series of a scalar climate variable for indications of climate change, an investigator might pick out what appears to be a linear trend commencing near the end of the record. Visual determination of the starting time ...

Donald B. Percival; D. Andrew Rothrock

2005-03-01T23:59:59.000Z

102

Prediction of long-range dependent time series data with performance guarantee  

Science Conference Proceedings (OSTI)

Modelling and predicting long-range dependent time series data can find important and practical applications in many areas such as telecommunications and finance. In this paper, we consider Fractional Autoregressive Integrated Moving Average (FARIMA) ...

Mikhail Dashevskiy; Zhiyuan Luo

2009-10-01T23:59:59.000Z

103

Modeling data with multiple time dimensions  

Science Conference Proceedings (OSTI)

A large class of problems in time series analysis can be represented by a set of overlapping time series with different starting times. These time series may be treated as different probes of the same underlying process. Such probes may follow a characteristic ... Keywords: Dendrochronology, Douglas fir, Dual-time dynamics, El Malpais, Generalized additive models, Global climate change, Non-linear dynamics, Non-linear modeling, Pinon pine, Ponderosa pine, Portfolio forecasting, Retail lending, SETI@home, Scenario-based forecasting, Search for extraterrestrial intelligence, Time series, Tree rings

Joseph L. Breeden

2007-05-01T23:59:59.000Z

104

Detection of trend changes in time series using Bayesian inference  

E-Print Network (OSTI)

Change points in time series are perceived as isolated singularities where two regular trends of a given signal do not match. The detection of such transitions is of fundamental interest for the understanding of the system's internal dynamics. In practice observational noise makes it difficult to detect such change points in time series. In this work we elaborate a Bayesian method to estimate the location of the singularities and to produce some confidence intervals. We validate the ability and sensitivity of our inference method by estimating change points of synthetic data sets. As an application we use our algorithm to analyze the annual flow volume of the Nile River at Aswan from 1871 to 1970, where we confirm a well-established significant transition point within the time series.

Schtz, Nadine

2011-01-01T23:59:59.000Z

105

SCHOOL OF MATHEMATICS AND STATISTICS Spring Semester Time Series 2 hours  

E-Print Network (OSTI)

to University regulations. There are 99 marks available on the paper. Please leave this exam paper on your desk time series and their relationship, using suitable technical terms and adding approximate quanti series model Xt = 1 3 Xt-1 + t + 1 2 t-1 - 1 4 t-2, where t is white noise with variance 4. (i) Explain

Oakley, Jeremy

106

Complexity analysis of the turbulent environmental fluid flow time series  

E-Print Network (OSTI)

We have used the Kolmogorov complexities, sample and permutation entropies to quantify the randomness degree in river flow time series of two mountain rivers in Bosnia and Herzegovina, representing the turbulent environmental fluid, for the period 1926-1990. In particular, we have examined the monthly river flow time series from two rivers (Miljacka and Bosnia) in mountain part of their flow and then calculated the Kolmogorov Complexity (KL) based on the Lempel-Ziv Algorithm (LZA) (Lower - KLL and Upper - KLU), Sample Entropy (SE) and Permutation Entropy (PE) values for each time series. The results indicate that the KLL, KLU, SE and PE values in two rivers are close to each other regardless of the amplitude differences in their monthly flow rates. We have illustrated the changes in mountain river flow complexity by experiments using (i) the data set for the Bosnia River and (ii) anticipated human activities and projected climate changes. We have explored the sensitivity of considered measures in dependence on the length of time series. In addition, we have divided the period 1926-1990 into three sub-intervals: (a) 1926-1945, (b)1946-1965 and (c)1966-1990, and calculated the KLL, KLU, SE and PE values for the various time series in these sub-intervals. It is found that during the period 1946-1965, there is a decrease in their complexities, and corresponding changes in the SE and PE, in comparison to the period 1926-1990. This complexity loss may be primarily attributed to (i) human interventions, after Second World War, on these rivers because of their use for water consumption and (ii) climate change in recent time.

Dragutin T. Mihailovic; Emilija Nikolic-Djoric; Nusret Dreskovic; Gordan Mimic

2013-01-10T23:59:59.000Z

107

Estimating the Correlation Dimension of Atmospheric Time Series  

Science Conference Proceedings (OSTI)

The correlation dimension D is commonly used to quantify the chaotic structure of atmospheric time series. The standard algorithm for estimating the value of D is based on finding the slope of the curve obtained by plotting ln C(r) versus ln r, ...

Hampton N. Shirer; Christian J. Fosmire; Robert Wells; Laurentia Suciu

1997-01-01T23:59:59.000Z

108

Analyses of Inhomogeneities in Radiosonde Temperature and Humidity Time Series  

Science Conference Proceedings (OSTI)

Twice daily radiosonde data from selected stations in the United States (period 1948 to 1990) and China (period 1958 to 1990) were sorted into time series. These stations have one sounding taken in darkness and the other in sunlight. The analysis ...

Panmao Zhai; Robert E. Eskridge

1996-04-01T23:59:59.000Z

109

Distribution Based Data Filtering for Financial Time Series Forecasting  

E-Print Network (OSTI)

of stock prices, which aims to forecast the future values of the price of a stock, in order to obtain/selling strategies to gain competitive advantage. Classic and popular methods for stock price forecasting [3Distribution Based Data Filtering for Financial Time Series Forecasting Goce Ristanoski1 , James

Bailey, James

110

Moored Salinity Time Series Measurements at 0, 140W  

Science Conference Proceedings (OSTI)

This study describes moored salinity time series measurements in a biologically productive equatorial upwelling regime in the Pacific Ocean (0, 140W). Data were collected at 26 m and at 100 m for 13 months during 19871988 using four SEACAT ...

Michael J. McPhaden; H. Paul Freitag; Andrew J. Shepherd

1990-08-01T23:59:59.000Z

111

Bayesian Variable Selection for Nowcasting Economic Time Series  

E-Print Network (OSTI)

motivation Want to use Google Trends data to nowcast economic series unemployment may be predicted by "job;Avoid spurious regression How to control for trend and seasonality? Build a model for the predictable-chosen contemporaneous regressors from Google Trends non-seasonal AR1: yt = a1yt-1 + bxt + et seasonal AR1: yt = a1yt-1

Varian, Hal R.

112

National Ignition Campaign (NIC) Precision Tuning Series Shock Timing Experiments  

Science Conference Proceedings (OSTI)

A series of precision shock timing experiments have been performed on NIF. These experiments continue to adjust the laser pulse shape and employ the adjusted cone fraction (CF) in the picket (1st 2 ns of the laser pulse) as determined from the re-emit experiment series. The NIF ignition laser pulse is precisely shaped and consists of a series of four impulses, which drive a corresponding series of shock waves of increasing strength to accelerate and compress the capsule ablator and fuel layer. To optimize the implosion, they tune not only the strength (or power) but also, to sub-nanosecond accuracy, the timing of the shock waves. In a well-tuned implosion, the shock waves work together to compress and heat the fuel. For the shock timing experiments, a re-entrant cone is inserted through both the hohlraum wall and the capsule ablator allowing a direct optical view of the propagating shocks in the capsule interior using the VISAR (Velocity Interferometer System for Any Reflector) diagnostic from outside the hohlraum. To emulate the DT ice of an ignition capsule, the inside of the cone and the capsule are filled with liquid deuterium.

Robey, H F; Celliers, P M

2011-07-19T23:59:59.000Z

113

Estimating the predictability of economic and financial time series  

E-Print Network (OSTI)

The predictability of a time series is determined by the sensitivity to initial conditions of its data generating process. In this paper our goal is to characterize this sensitivity from a finite sample by assuming few hypotheses on the data generating model structure. In order to measure the distance between two trajectories induced by a same noisy chaotic dynamic from two close initial conditions, a symmetric Kullback-Leiber divergence measure is used. Our approach allows to take into account the dependence of the residual variance on initial conditions. We show it is linked to a Fisher information matrix and we investigated its expressions in the cases of covariance-stationary processes and ARCH($\\infty$) processes. Moreover, we propose a consistent non-parametric estimator of this sensitivity matrix in the case of conditionally heteroscedastic autoregressive nonlinear processes. Various statistical hypotheses can so be tested as for instance the hypothesis that the data generating process is "almost" independently distributed at a given moment. Applications to simulated data and to the stock market index S&P500 illustrate our findings. More particularly, we highlight a significant relationship between the sensitivity to initial conditions of the daily returns of the S&P 500 and their volatility.

Quentin Giai Gianetto; Jean-Marc Le Caillec; Erwan Marrec

2012-12-12T23:59:59.000Z

114

Faster and parameter-free discord search in quasi-periodic time series  

Science Conference Proceedings (OSTI)

Time series discord has proven to be a useful concept for time-series anomaly identification. To search for discords, various algorithms have been developed. Most of these algorithms rely on pre-building an index (such as a trie) for subsequences. Users ... Keywords: anomaly detection, minimax search, periodic time series, time series data mining, time series discord

Wei Luo; Marcus Gallagher

2011-05-01T23:59:59.000Z

115

Spectral analysis of microarray gene expression time series data of Plasmodium falciparum  

Science Conference Proceedings (OSTI)

We propose a new strategy to analyse the periodicity of gene expression profiles using Singular Spectrum Analysis (SSA) and Autoregressive (AR) model based spectral estimation. By combining the advantages of SSA and AR modelling, more ... Keywords: SSA, autoregressive spectral estimation model, bioinformatics, drug discovery, gene expression profiles, gene target, microarray time series analysis, plasmodium falciparum, singular spectrum analysis

Liping Du; Shuanhu Wu; Alan Wee-Chung Liew; David K. Smith; Hong Yan

2008-07-01T23:59:59.000Z

116

CDIAC::Carbon Emission::Time Series Global Data  

NLE Websites -- All DOE Office Websites (Extended Search)

The 2013 version of this database presents a time series recording 1° The 2013 version of this database presents a time series recording 1° latitude by 1° longitude CO2 emissions in units of million metric tons of carbon per year from anthropogenic sources for 1751-2010. Detailed geographic information on CO2 emissions can be critical in understanding the pattern of the atmospheric and biospheric response to these emissions. Global, regional, and national annual estimates for 1751 through 2010 were published earlier (Boden et al. 2013). Those national, annual CO2 emission estimates were based on statistics about fossil-fuel burning, cement manufacturing and gas flaring in oil fields as well as energy production, consumption, and trade data, using the methods of Marland and Rotty (1984). The national annual estimates were combined with gridded 1° data on

117

Time Series, Stochastic Processes and Completeness of Quantum Theory  

Science Conference Proceedings (OSTI)

Most of physical experiments are usually described as repeated measurements of some random variables. Experimental data registered by on?line computers form time series of outcomes. The frequencies of different outcomes are compared with the probabilities provided by the algorithms of quantum theory (QT). In spite of statistical predictions of QT a claim was made that it provided the most complete description of the data and of the underlying physical phenomena. This claim could be easily rejected if some fine structures

2011-01-01T23:59:59.000Z

118

Complexity analysis of the UV radiation dose time series  

E-Print Network (OSTI)

We have used the Lempel-Ziv and sample entropy measures to assess the complexity in the UV radiation activity in the Vojvodina region (Serbia) for the period 1990-2007. In particular, we have examined the reconstructed daily sum (dose) of the UV-B time series from seven representative places in this region and calculated the Lempel-Ziv Complexity (LZC) and Sample Entropy (SE) values for each time series. The results indicate that the LZC values in some places are close to each other while in others they differ. We have devided the period 1990-2007 into two subintervals: (a) 1990-1998 and (b) 1999-2007 and calculated LZC and SE values for the various time series in these subintervals. It is found that during the period 1999-2007, there is a decrease in their complexities, and corresponding changes in the SE, in comparison to the period 1990-1998. This complexity loss may be attributed to increased (i) human intervention in the post civil war period (land and crop use and urbanization) and military activities i...

Mihailovic, Dragutin T

2013-01-01T23:59:59.000Z

119

Trend Change Detection in NDVI Time Series: Effects of Inter-Annual Variability and Methodology  

E-Print Network (OSTI)

Abstract: Changing trends in ecosystem productivity can be quantified using satellite observations of Normalized Difference Vegetation Index (NDVI). However, the estimation of trends from NDVI time series differs substantially depending on analyzed satellite dataset, the corresponding spatiotemporal resolution, and the applied statistical method. Here we compare the performance of a wide range of trend estimation methods and demonstrate that performance decreases with increasing inter-annual variability in the NDVI time series. Trend slope estimates based on annual aggregated time series or based on a seasonal-trend model show better performances than methods that remove the seasonal cycle of the time series. A breakpoint detection analysis reveals that an overestimation of breakpoints in NDVI trends can result in wrong or even opposite trend estimates. Based on our results, we give practical recommendations for the application of trend methods on long-term NDVI time series. Particularly, we apply and compare different methods on NDVI time series in Alaska, where both greening and browning trends have been previously observed. Here, the multi-method uncertainty of NDVI trendsRemote Sens. 2013, 5 2114

Matthias Forkel; Nuno Carvalhais; Jan Verbesselt; Miguel D. Mahecha; Christopher S. R. Neigh; Markus Reichstein

2013-01-01T23:59:59.000Z

120

Dynamic predication model for integrated series and application  

Science Conference Proceedings (OSTI)

In the paper a predication model for integrated series is proposed. Granger causality analysis is deployed first for finding out the cointegrated series for the interested series. Then granger causality information is used for the identification of the ... Keywords: cointegration series, dynamic prediction, electricity demand, granger causality

Yuan Jia-hai; Zhao Zhi; Xiong Min-peng

2006-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "time series models" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Statistical and Multifractal Properties of the Time Series Generated by a Modified Minority Game  

E-Print Network (OSTI)

In this paper it was developed a modification of the known multiagent model Minority Game, designed to simulate the behavior of traders in financial markets and the resulting price dynamics on the abstract resource. The model was implemented in the form of software. The modified version of Minority Game was investigated with the aim of reproducing the basic properties of real financial time series. It was proved that such properties as the clustering of volatility, the Levy distribution and multifractality are inherent for generated by this version of the Minority Game time series of prices.

Kuperin, Yu A

2010-01-01T23:59:59.000Z

122

Superstatistical fluctuations in time series: applications to share price dynamics and turbulence  

E-Print Network (OSTI)

We introduce a general technique to study whether a given experimental time series is superstatistical. Crucial for the applicability of the superstatistics concept is the existence of a parameter $\\beta$ that fluctuates on a large time scale as compared to the other time scales of the complex system under consideration. The proposed method extracts the main superstatistical parameters out of a given data set and checks the validity of the superstatistical model assumptions. We test the method thoroughly with surrogate data sets. Then the applicability of the superstatistical approach is illustrated using real experimental data. We study two examples, velocity time series measured in turbulent Taylor-Couette flows and time series of log-returns of the closing prices of some stock market indices.

Van der Straeten, Erik

2009-01-01T23:59:59.000Z

123

Classification of Multi-Dimensional Streaming Time Series by Weighting each Classifier's Track Record  

E-Print Network (OSTI)

increasingly, home-based) medical devices can produce time series streams from more than twenty sensors

Keogh, Eammon

124

Forecasting in high order fuzzy times series by using neural networks to define fuzzy relations  

Science Conference Proceedings (OSTI)

A given observation in time series does not only depend on preceding one but also previous ones in general. Therefore, high order fuzzy time series approach might obtain better forecasts than does first order fuzzy time series approach. Defining fuzzy ... Keywords: Forecasting, Fuzzy relation, Fuzzy set, High order fuzzy time series, Neural networks

Cagdas H. Aladag; Murat A. Basaran; Erol Egrioglu; Ufuk Yolcu; Vedide R. Uslu

2009-04-01T23:59:59.000Z

125

Time series power flow analysis for distribution connected PV generation.  

SciTech Connect

Distributed photovoltaic (PV) projects must go through an interconnection study process before connecting to the distribution grid. These studies are intended to identify the likely impacts and mitigation alternatives. In the majority of the cases, system impacts can be ruled out or mitigation can be identified without an involved study, through a screening process or a simple supplemental review study. For some proposed projects, expensive and time-consuming interconnection studies are required. The challenges to performing the studies are twofold. First, every study scenario is potentially unique, as the studies are often highly specific to the amount of PV generation capacity that varies greatly from feeder to feeder and is often unevenly distributed along the same feeder. This can cause location-specific impacts and mitigations. The second challenge is the inherent variability in PV power output which can interact with feeder operation in complex ways, by affecting the operation of voltage regulation and protection devices. The typical simulation tools and methods in use today for distribution system planning are often not adequate to accurately assess these potential impacts. This report demonstrates how quasi-static time series (QSTS) simulation and high time-resolution data can be used to assess the potential impacts in a more comprehensive manner. The QSTS simulations are applied to a set of sample feeders with high PV deployment to illustrate the usefulness of the approach. The report describes methods that can help determine how PV affects distribution system operations. The simulation results are focused on enhancing the understanding of the underlying technical issues. The examples also highlight the steps needed to perform QSTS simulation and describe the data needed to drive the simulations. The goal of this report is to make the methodology of time series power flow analysis readily accessible to utilities and others responsible for evaluating potential PV impacts.

Broderick, Robert Joseph; Quiroz, Jimmy Edward; Ellis, Abraham; Reno, Matthew J. [Georgia Institute of Technology, Atlanta, GA; Smith, Jeff [Electric Power Research Institute, Knoxville, TN; Dugan, Roger [Electric Power Research Institute, Knoxville, TN

2013-01-01T23:59:59.000Z

126

Fusion of hypothesis testing for nonlinearity detection in small time series  

Science Conference Proceedings (OSTI)

The performances of parametric or non-parametric Hypothesis Testing (HT) for nonlinearity detection are fairly weak for small time series (typically between 128 and 512 samples). A natural idea to improve the results is to merge several HT to make a ... Keywords: Decision fusion, HOS methods, Hypothesis testing fusion, Mutual information, Nonlinearity detection, Signal modelling

Jean-Marc Le Caillec; Julien Montagner

2013-05-01T23:59:59.000Z

127

Nonparametric inference of quantile curves for nonstationary time series  

E-Print Network (OSTI)

The paper considers nonparametric specification tests of quantile curves for a general class of nonstationary processes. Using Bahadur representation and Gaussian approximation results for nonstationary time series, simultaneous confidence bands and integrated squared difference tests are proposed to test various parametric forms of the quantile curves with asymptotically correct type I error rates. A wild bootstrap procedure is implemented to alleviate the problem of slow convergence of the asymptotic results. In particular, our results can be used to test the trends of extremes of climate variables, an important problem in understanding climate change. Our methodology is applied to the analysis of the maximum speed of tropical cyclone winds. It was found that an inhomogeneous upward trend for cyclone wind speeds is pronounced at high quantile values. However, there is no trend in the mean lifetime-maximum wind speed. This example shows the effectiveness of the quantile regression technique.

Zhou, Zhou

2010-01-01T23:59:59.000Z

128

Soft computing methods to predict gene regulatory networks: An integrative approach on time-series gene expression data  

Science Conference Proceedings (OSTI)

To unravel the controlling mechanisms of gene regulation, in this paper we present the application of sophisticated soft computing methods applied on an important problem from Bioinformatics-inferring gene regulatory networks (GRN) from time series gene ... Keywords: Automatic model building, Gene regulatory network, LARS, Reverse-engineering, Schizosaccharomyces pombe, Time series microarray data, Yeast

Zeke S. H. Chan; Ilkka Havukkala; Vishal Jain; Yingjie Hu; Nikola Kasabov

2008-06-01T23:59:59.000Z

129

Six-Week Time Series Of Eddy Covariance Co2 Flux At Mammoth Mountain,  

Open Energy Info (EERE)

Six-Week Time Series Of Eddy Covariance Co2 Flux At Mammoth Mountain, Six-Week Time Series Of Eddy Covariance Co2 Flux At Mammoth Mountain, California- Performance Evaluation And Role Of Meteorological Forcing Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Six-Week Time Series Of Eddy Covariance Co2 Flux At Mammoth Mountain, California- Performance Evaluation And Role Of Meteorological Forcing Details Activities (1) Areas (1) Regions (0) Abstract: CO2 and heat fluxes were measured over a six-week period (09/08/2006 to 10/24/2006) by the eddy covariance (EC) technique at the Horseshoe Lake tree kill (HLTK), Mammoth Mountain, CA, a site with complex terrain and high, spatially heterogeneous CO2 emission rates. EC CO2 fluxes ranged from 218 to 3500 g m- 2 d- 1 (mean = 1346 g m- 2 d- 1). Using footprint modeling, EC CO2 fluxes were compared to CO2 fluxes measured by

130

Independent arrays or independent time courses for gene expression time series data analysis  

Science Conference Proceedings (OSTI)

In this paper we apply three different independent component analysis (ICA) methods, including spatial ICA (sICA), temporal ICA (tICA), and spatiotemporal ICA (stICA), to gene expression time series data and compare their performance in clustering genes ... Keywords: DNA microarray, Gene expression data, Independent component analysis, Principal component analysis

Sookjeong Kim; Jong Kyoung Kim; Seungjin Choi

2008-06-01T23:59:59.000Z

131

Multifractal analysis of stress time series during ultrathin lubricant film melting  

E-Print Network (OSTI)

Melting of an ultrathin lubricant film confined between two atomically flat surfaces is we studied using the rheological model for viscoelastic matter approximation. Phase diagram with domains, corresponding to sliding, dry, and two types of $stick-slip$ friction regimes has been built taking into account additive noises of stress, strain, and temperature of the lubricant. The stress time series have been obtained for all regimes of friction using the Stratonovich interpretation. It has been shown that self-similar regime of lubricant melting is observed when intensity of temperature noise is much larger than intensities of strain and stress noises. This regime is defined by homogenous distribution, at which characteristic stress scale is absent. We study stress time series obtained for all friction regimes using multifractal detrended fluctuation analysis. It has been shown that multifractality of these series is caused by different correlations that are present in the system and also by a power-law distribu...

Khomenko, A V; Borisyuk, V N; 10.1142/S0219477510000046

2010-01-01T23:59:59.000Z

132

An Algorithm for Classification and Outlier Detection of Time-Series Data  

Science Conference Proceedings (OSTI)

An algorithm to perform outlier detection on time-series data is developed, the intelligent outlier detection algorithm (IODA). This algorithm treats a time series as an image and segments the image into clusters of interest, such as nominal ...

R. Andrew Weekley; Robert K. Goodrich; Larry B. Cornman

2010-01-01T23:59:59.000Z

133

Bermudas Tale of Two Time Series: Hydrostation S and BATS  

Science Conference Proceedings (OSTI)

This paper describes the oceanic variability at Bermuda between 1989 and 1999, recorded in two overlapping hydrographic time series. Station S and Bermuda Atlantic Time Series Study (BATS), which are 60 km apart, both show that a multidecadal ...

Helen E. Phillips; Terrence M. Joyce

2007-03-01T23:59:59.000Z

134

VTG schemes for using back propagation for multivariate time series prediction  

Science Conference Proceedings (OSTI)

This research proposes the three schemes of estimating and adding mid-terms to multivariate time series. In this research, the back propagation is adopted as the approach to multivariate time series prediction. It is traditionally designed for the task ... Keywords: Multivariate time series prediction, Neural networks, Virtual terms

Taeho Jo

2013-05-01T23:59:59.000Z

135

An adaptive algorithm for online time series segmentation with error bound guarantee  

Science Conference Proceedings (OSTI)

The volume of time series data grows rapidly in various applications such as network traffic management, telecommunications, finance and sensor network. To reduce the cost of storage, transmission and processing of time series data, the need for more ... Keywords: approximation, segmentation, time series

Zhenghua Xu; Rui Zhang; Ramamohanarao Kotagiri; Udaya Parampalli

2012-03-01T23:59:59.000Z

136

hal-00122749,version1-8Jan2007 Time Series Forecasting: Obtaining Long Term Trends with  

E-Print Network (OSTI)

. For example when forecast- ing an electrical consumption, it could be advan- tageous to predict all hourly As second example, we use the Polish electrical load time series [ 6]. This series contains hourly valueshal-00122749,version1-8Jan2007 Time Series Forecasting: Obtaining Long Term Trends with Self

Paris-Sud XI, Université de

137

Double SOM for long-term time series prediction Geoffroy Simon1  

E-Print Network (OSTI)

-term prediction, self-organizing maps, Santa Fe, electrical load Abstract --- Many time series forecasting, the Santa Fe A series and a problem of electrical load forecasting. 2 Time series prediction The classical in one bloc, rather than a single t+1 scalar value. For example, in an electrical load forecasting

Paris-Sud XI, Université de

138

Engine Control Improvement through Application of Chaotic Time Series Analysis  

SciTech Connect

The objective of this program was to investigate cyclic variations in spark-ignition (SI) engines under lean fueling conditions and to develop options to reduce emissions of nitrogen oxides (NOx) and particulate matter (PM) in compression-ignition direct-injection (CIDI) engines at high exhaust gas recirculation (EGR) rates. The CIDI activity builds upon an earlier collaboration between ORNL and Ford examining combustion instabilities in SI engines. Under the original CRADA, the principal objective was to understand the fundamental causes of combustion instability in spark-ignition engines operating with lean fueling. The results of this earlier activity demonstrated that such combustion instabilities are dominated by the effects of residual gas remaining in each cylinder from one cycle to the next. A very simple, low-order model was developed that explained the observed combustion instability as a noisy nonlinear dynamical process. The model concept lead to development of a real-time control strategy that could be employed to significantly reduce cyclic variations in real engines using existing sensors and engine control systems. This collaboration led to the issuance of a joint patent for spark-ignition engine control. After a few years, the CRADA was modified to focus more on EGR and CIDI engines. The modified CRADA examined relationships between EGR, combustion, and emissions in CIDI engines. Information from CIDI engine experiments, data analysis, and modeling were employed to identify and characterize new combustion regimes where it is possible to simultaneously achieve significant reductions in NOx and PM emissions. These results were also used to develop an on-line combustion diagnostic (virtual sensor) to make cycle-resolved combustion quality assessments for active feedback control. Extensive experiments on engines at Ford and ORNL led to the development of the virtual sensor concept that may be able to detect simultaneous reductions in NOx and PM emissions under low temperature combustion (LTC) regimes. An invention disclosure was submitted to ORNL for the virtual sensor under the CRADA. Industrial in-kind support was available throughout the project period. Review of the research results were carried out on a regular basis (annual reports and meetings) followed by suggestions for improvement in ongoing work and direction for future work. A significant portion of the industrial support was in the form of experimentation, data analysis, data exchange, and technical consultation.

Green, J.B., Jr.; Daw, C.S.

2003-07-15T23:59:59.000Z

139

Separation of Stochastic and Deterministic Information from Seismological Time Series with Nonlinear Dynamics and Maximum Entropy Methods  

SciTech Connect

We present a procedure developed to detect stochastic and deterministic information contained in empirical time series, useful to characterize and make models of different aspects of complex phenomena represented by such data. This procedure is applied to a seismological time series to obtain new information to study and understand geological phenomena. We use concepts and methods from nonlinear dynamics and maximum entropy. The mentioned method allows an optimal analysis of the available information.

Gutierrez, Rafael M.; Useche, Gina M.; Buitrago, Elias [Centro de Investigaciones, Universidad Antonio Narino, Carrera 3 Este No. 47A--15 Bogota (Colombia)

2007-11-13T23:59:59.000Z

140

SumTime-Turbine: A Knowledge-Based System to Communicate Gas Turbine Time-Series Data  

E-Print Network (OSTI)

SumTime-Turbine: A Knowledge-Based System to Communicate Gas Turbine Time-Series Data Jin Yu produces textual summaries of archived time- series data from gas turbines. These summaries should help evaluated. 1 Introduction In order to get the most out of gas turbines, TIGER [2] has been developed

Reiter, Ehud

Note: This page contains sample records for the topic "time series models" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Learning to imitate stochastic time series in a compositional way by chaos  

E-Print Network (OSTI)

This study shows that a mixture of RNN experts model can acquire the ability to generate sequences combining multiple primitive patterns by means of self-organizing chaos. By training of the model, each expert learns a primitive sequence pattern, and a gating network learns to imitate stochastic switching of the multiple primitives via a chaotic dynamics, utilizing a sensitive dependence on initial conditions. As a demonstration, we present a numerical simulation in which the model learns Markov chain switching among some Lissajous curves by a chaotic dynamics. Our analysis shows that by using a sufficient amount of training data, balanced with the network memory capacity, it is possible to satisfy the conditions for embedding the target stochastic sequences into a chaotic dynamical system. It is also shown that reconstruction of a stochastic time series by a chaotic model can be stabilized by adding a negligible amount of noise to the dynamics of the model.

Jun Namikawa; Jun Tani

2008-05-13T23:59:59.000Z

142

SERIES  

E-Print Network (OSTI)

Abstract: There is a growing interest in relating agent-based models to realworld locations by combining them with geographical information systems (GIS) which can be seen with the proliferation of geosimulation models in recent years. This coincides with the proliferation of digital data both in the two and three dimensions allowing one to construct detailed and extensive feature rich and highly visual 3D city models. This paper explores some of these developments in relation to our own initial work on building 3D geospatial agent-based models of urban systems and the technologies that allow for such models to be created. Furthermore, we highlight some techniques for the creation of 3D agent-based models and stress that such models are not a substitute to good models. 1 1

A. T. Crooks; A. Hudson-smith; A Patel

2010-01-01T23:59:59.000Z

143

Environmental time series analysis and forecasting with the Captain toolbox  

Science Conference Proceedings (OSTI)

The Data-Based Mechanistic (DBM) modelling philosophy emphasises the importance of parametrically efficient, low order, 'dominant mode' models, as well as the development of stochastic methods and the associated statistical analysis required for their ... Keywords: DAR, DARX, DBM, DHR, DLR, DTF, Data-based mechanistic, FIS, Fixed interval smoothing, Forecasting, GRW, Hyper-parameter optimisation, IRW, IV, Identification, Kalman filtering, MISO, ML, Maximum likelihood, NVR, RIV, RW, SDP, SRIV, SRW, Signal processing, TF, TVP, UC, Unobserved components model, YIC

C. James Taylor; Diego J. Pedregal; Peter C. Young; Wlodek Tych

2007-06-01T23:59:59.000Z

144

Six-Week Time Series Of Eddy Covariance Co2 Flux At Mammoth Mountain...  

Open Energy Info (EERE)

Six-Week Time Series Of Eddy Covariance Co2 Flux At Mammoth Mountain, California- Performance Evaluation And Role Of Meteorological Forcing Jump to: navigation, search GEOTHERMAL...

145

A Radial Basis Function Approach to Financial Time Series Analysis  

E-Print Network (OSTI)

Nonlinear multivariate statistical techniques on fast computers offer the potential to capture more of the dynamics of the high dimensional, noisy systems underlying financial markets than traditional models, while ...

Hutchinson, James M.

1993-12-01T23:59:59.000Z

146

Abstract--This paper analyzes a distribution system load time series through autocorrelation coefficient, power spectral density,  

E-Print Network (OSTI)

models [7], [8]. The load model developed in [7] provides different 24-hour load profiles for different seasons. The 24-hour load profile is obtained by a weighted sum of peak loads from different types1 Abstract--This paper analyzes a distribution system load time series through autocorrelation

Bak-Jensen, Birgitte

147

Multifractal analysis of stress time series during ultrathin lubricant film melting  

E-Print Network (OSTI)

Melting of an ultrathin lubricant film confined between two atomically flat surfaces is we studied using the rheological model for viscoelastic matter approximation. Phase diagram with domains, corresponding to sliding, dry, and two types of $stick-slip$ friction regimes has been built taking into account additive noises of stress, strain, and temperature of the lubricant. The stress time series have been obtained for all regimes of friction using the Stratonovich interpretation. It has been shown that self-similar regime of lubricant melting is observed when intensity of temperature noise is much larger than intensities of strain and stress noises. This regime is defined by homogenous distribution, at which characteristic stress scale is absent. We study stress time series obtained for all friction regimes using multifractal detrended fluctuation analysis. It has been shown that multifractality of these series is caused by different correlations that are present in the system and also by a power-law distribution. Since the power-law distribution is related to small stresses, this case corresponds to self-similar solid-like lubricant.

A. V. Khomenko; I. A. Lyashenko; V. N. Borisyuk

2010-07-20T23:59:59.000Z

148

Stochastic Simulation Methods for Precipitation and Streamflow Time Series  

E-Print Network (OSTI)

One major acknowledged challenge in daily precipitation is the inability to model extreme events in the spectrum of events. These extreme events are rare but may cause large losses. How to realistically simulate extreme behavior of daily precipitation is necessary and important. To that end, a hybrid probability distribution is developed. The logic of this distribution is to simulate the low to moderate values by an exponential distribution and extremes by a generalized Pareto distribution. Compared with alternatives, the developed hybrid distribution is capable of simulating the entire range of precipitation amount and is much easier to use. The hybrid distribution is then used to construct a bivariate discrete-continuous mixed distribution, which is used for building a daily precipitation generator. The developed generator can successfully reproduce extreme events. Compared with other widely used generators, the most important advantage of the developed generator is that it is apt at extrapolating values significantly beyond the upper range of observed data. The major challenge in monthly streamflow simulation is referred to the underrepresentation of inter-annual variability. The inter-annual variability is often related with sustained droughts or periods of high flows. Preserving inter-annual variability is thus of particular importance for the long-term management of water resources systems. To that end, variables conveying such inter-annual signals should be used as covariates. This requires models that must be flexible at incorporating as many covariates as necessary. Keeping this point in mind, a joint conditional density estimation network is developed. Therein, the joint distribution of streamflows of two adjacent months is assumed to follow a specific parametric family. Parameters of the distribution are estimated by an artificial neural network. Due to the seasonal concentration of precipitation or the joint effect of rainfall and snowmelt, monthly streamflow distribution sometimes may exhibit a bimodal shape. To reproduce bimodality, nonparametric models are often preferred. However, the simulated sequences from existing nonparametric models represent too close a resemblance to historical record. To address this issue, while retaining typical merits of nonparametric models, a multi-model regression-sampling algorithm with a few weak assumptions is developed. Collecting hydrometric data is the first step for building hydrologic models, and for planning, design, operation, and management of water resource systems. In this dissertation, an entropy-theory-based criterion, termed maximum information minimum redundancy, is proposed for hydrometric monitoring network evaluation and design. Compared with existing similar approaches, the criterion is apt at finding stations with high information content, and locating independent stations.

Li, Chao

2013-05-01T23:59:59.000Z

149

Bayesian analysis of time series of single RNA under fluctuating force  

E-Print Network (OSTI)

Extracting the intrinsic kinetic information of biological molecule from its single-molecule kinetic data is of considerable biophysical interest. In this work, we theoretically investigate the feasibility of inferring single RNA's intrinsic kinetic parameters from the time series obtained by forced folding/unfolding experiment done in the light tweezer, where the molecule is flanked by long double-stranded DNA/RNA handles and tethered between two big beads. We first construct a coarse-grain physical model of the experimental system. The model has captured the major physical factors: the Brownian motion of the bead, the molecular structural transition, and the elasticity of the handles and RNA. Then based on an analytic solution of the model, a Bayesian method using Monte Carlo Markov Chain is proposed to infer the intrinsic kinetic parameters of the RNA from the noisy time series of the distance or force. Because the force fluctuation induced by the Brownian motion of the bead and the structural transition can significantly modulate the transition rates of the RNA, we prove that, this statistic method is more accurate and efficient than the conventional histogram fitting method in inferring the molecule's intrinsic parameters.

Fei Liu; Zhong-can Ou-Yang

2007-10-04T23:59:59.000Z

150

A test for second order stationarity of a time series based on the Discrete Fourier Transform  

E-Print Network (OSTI)

A test for second order stationarity of a time series based on the Discrete Fourier Transform property, we construct a Portmanteau type test statistic for testing stationarity of the time series. It is shown that under the null of stationarity, the test statistic is approximately a chi square distribution

Subba Rao, Suhasini

151

Classification of Multivariate Time Series and Structured Data Using Constructive Induction  

Science Conference Proceedings (OSTI)

We present a method of constructive induction aimed at learning tasks involving multivariate time series data. Using metafeatures, the scope of attribute-value learning is expanded to domains with instances that have some kind of recurring substructure, ... Keywords: constructive induction, propositionalisation, substructure, time series

Mohammed Waleed Kadous; Claude Sammut

2005-02-01T23:59:59.000Z

152

On the Average Value of Correlated Time Series, with Applications in Dendroclimatology and Hydrometeorology  

Science Conference Proceedings (OSTI)

In a number of areas of applied climatology, time series are either averaged to enhance a common underlying signal or combined to produce area averages. How well, then, does the average of a finite number (N) of time series represent the ...

T. M. L. Wigley; K. R. Briffa; P. D. Jones

1984-02-01T23:59:59.000Z

153

Aggregation of asynchronous electric power consumption time series knowing the integral  

Science Conference Proceedings (OSTI)

More and more data mining algorithms are applied to a large number of long time series issued by many distributed sensors. The consequence of the huge volume of data is that data warehouses often contain asynchronous time series, i.e. the values have ...

Raja Chiky; Laurent Decreusefond; Georges Hbrail

2010-03-01T23:59:59.000Z

154

Lean Blow-Out Prediction in Gas Turbine Combustors Using Symbolic Time Series Analysis  

E-Print Network (OSTI)

Lean Blow-Out Prediction in Gas Turbine Combustors Using Symbolic Time Series Analysis Achintya of lean blowout in gas turbine combustors based on symbolic analysis of time series data from optical. For the purpose of detecting lean blowout in gas turbine combustors, the state probability vector obtained

Ray, Asok

155

Fast algorithms for time series with applications to finance, physics, music, biology, and other suspects  

Science Conference Proceedings (OSTI)

Financial time series streams are watched closely by millions of traders. What exactly do they look for and how can we help them do it faster? Physicists study the time series emerging from their sensors. The same question holds for them. Musicians produce ...

Alberto Lerner; Dennis Shasha; Zhihua Wang; Xiaojian Zhao; Yunyue Zhu

2004-06-01T23:59:59.000Z

156

Mining pixel evolutions in satellite image time series for agricultural monitoring  

Science Conference Proceedings (OSTI)

In this paper, we present a technique to help the experts in agricultural monitoring, by mining Satellite Image Time Series over cultivated areas. We use frequent sequential patterns extended to this spatiotemporal context in order to extract sets of ... Keywords: agricultural monitoring, constraints, satellite image time series, spatiotemporal patterns

Andreea Julea; Nicolas Mger; Christophe Rigotti; Emmanuel Trouv; Philippe Bolon; Vasile L?z?rescu

2011-08-01T23:59:59.000Z

157

Time Series Prediction of Mining Subsidence Based on Genetic Algorithm Neural Network  

Science Conference Proceedings (OSTI)

In order to find out the dynamics law of underground coal mining subsidence, BP neural network was used for time series prediction. First, genetic algorithm was used to optimize the initial network weight to overcome the inherent defects of BP neural ... Keywords: Mining subsidence, time series, BP neural network, genetic algorithm

Peixian Li; Zhixiang Tan; Lili Yan; Kazhong Deng

2011-07-01T23:59:59.000Z

158

Fast and exact synthesis of stationary multivariate Gaussian time series using circulant embedding  

Science Conference Proceedings (OSTI)

A fast and exact procedure for the numerical synthesis of stationary multivariate Gaussian time series with a priori prescribed and well controlled auto- and cross-covariance functions is proposed. It is based on extending the circulant embedding technique ... Keywords: Circulant embedding, Multivariate Gaussian series, Numerical synthesis, Stationarity, Time-reversibility

Hannes Helgason; Vladas Pipiras; Patrice Abry

2011-05-01T23:59:59.000Z

159

Discovery of temporal variation of arsenic in a historical blackfoot disease territory by time series analysis  

Science Conference Proceedings (OSTI)

Time series analysis is useful tool for extracting interesting pattern from ordered sequence of observations. The Chianan Blackfoot disease region was selected as study area, and the monitoring data of arsenic in groundwater during the period of 2003 ... Keywords: arsenic, data mining, groundwater management, time series analysis, water quality

Jan-Yee Lee; Ting-Nien Wu

2009-08-01T23:59:59.000Z

160

Discovery of Temporal Variation of Arsenic in a Historical Blackfoot Disease Territory by Time Series Analysis  

Science Conference Proceedings (OSTI)

Time series analysis is useful tool for extracting interesting pattern from ordered sequence of observations. The Chianan Blackfoot disease region was selected as study area, and the monitoring data of arsenic in groundwater during the period of 2003 ... Keywords: groundwater management, data mining, time series analysis, arsenic, water quality

Jan-Yee Lee; Ting-Nien Wu

2009-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "time series models" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

A geometrical solution to time series searching invariant to shifting and scaling  

Science Conference Proceedings (OSTI)

The technique of searching for similar patterns among time series data is very useful in many applications. The problem becomes difficult when shifting and scaling are considered. We find that we can treat the problem geometrically and the major contribution ... Keywords: information search and retrieval, similarity search, spatial indexing, time series database

Mi Zhou; Man-Hon Wong; Kam-Wing Chu

2006-02-01T23:59:59.000Z

162

A prediction method for time series based on wavelet neural networks  

Science Conference Proceedings (OSTI)

This paper introduces a prediction method for time series that is based on the multi-resolution analysis of wavelets (MRA). The MRA is better able to decompose the non-stationary time series of nonlinear systems into different components, allowing a ...

Xiaobing Gan; Ying Liu; Francis R. Austin

2005-12-01T23:59:59.000Z

163

Statistical properties of information flow in financial time series  

E-Print Network (OSTI)

In this study, we tested possible factors that influence the information flow in the stock market. The time dependency, market factors, and market status were assessed using the Korean and US stock market data. We determined that all tested factors were significantly related to the information flow between stocks. Additionally, we have employed an original network consisting of stocks and networks by the minimal spanning tree (MST) method, in order to find a alternative method by which we could effectively investigate the characteristics of information flow between stocks. The empirical evidences gathered using $N-1$ links by the MST method did not differ when $N(N-1)/2$ whole links by the original network were used. These results indicate that links selected via the MST method may be reflective of meaningful characteristics of information flow between stocks in the market.

Eom, Cheoljun; Jung, Woo-Sung

2008-01-01T23:59:59.000Z

164

Simulation of wind-speed time series for wind-energy conversion analysis.  

DOE Green Energy (OSTI)

In order to investigate operating characteristics of a wind energy conversion system it is often desirable to have a sequential record of wind speeds. Sometimes a long enough actual data record is not available at the time an analysis is needed. This may be the case if, e.g., data are recorded three times a day at a candidate wind turbine site, and then the hourly performance of generated power is desired. In such cases it is often possible to use statistical characteristics of the wind speed data to calibrate a stochastic model and then generate a simulated wind speed time series. Any length of record may be simulated by this method, and desired system characteristics may be studied. A simple wind speed simulation model, WEISIM, is developed based on the Weibull probability distribution for wind speeds with a correction based on the lag-one autocorrelation value. The model can simulate at rates from one a second to one an hour, and wind speeds can represent short-term averages (e.g., 1-sec averages) or longer-term averages (e.g., 1-min or 1 hr averages). The validity of the model is verified with PNL data for both histogram characteristics and persistance characteristics.

Corotis, R.B.

1982-06-01T23:59:59.000Z

165

Use of a Principal Components Analysis for the Generation of Daily Time Series  

Science Conference Proceedings (OSTI)

A new approach for generating daily time series is considered in response to the weather-derivatives market. This approach consists of performing a principal components analysis to create independent variables, the values of which are then ...

Christine Dreveton; Yann Guillou

2004-07-01T23:59:59.000Z

166

A New StatisticalDynamical Downscaling Procedure Based on EOF Analysis for Regional Time Series Generation  

Science Conference Proceedings (OSTI)

A new statisticaldynamical downscaling procedure is developed and then applied to high-resolution (regional) time series generation and wind resource assessment. The statistical module of the new procedure uses empirical orthogonal function (EOF) ...

Yosvany Martinez; Wei Yu; Hai Lin

2013-04-01T23:59:59.000Z

167

High performance data mining in time series: techniques and case studies  

Science Conference Proceedings (OSTI)

As extremely large time series data sets grow more prevalent in a wide variety of settings, we face the significant challenge of developing efficient analysis methods. This dissertation addresses the problem in designing fast, scalable algorithms for ...

Yunyue Zhu / Dennis Shasha

2004-01-01T23:59:59.000Z

168

Inferring mechanism from time-series data: Delay-differential equations  

E-Print Network (OSTI)

D 110 (1997) 182194 Fig. 3. ACF of the residual errors ofautocorrelation function (ACF) as the diagnostic for non-autocorrelation function (ACF) of the residual time series.

Ellner, Stephen Paul; Kendall, Bruce E.; Wood, Simon N.; McCauley, Ed; Briggs, Cheryl J

1997-01-01T23:59:59.000Z

169

A Nonparametric Approach to the Removal of Documented Inhomogeneities in Climate Time Series  

Science Conference Proceedings (OSTI)

Climate data often suffer from artificial inhomogeneities, resulting from documented or undocumented events. For a time series to be used with confidence in climate analysis, it should only be characterized by variations intrinsic to the climate ...

Chiara Ambrosino; Richard E. Chandler

2013-05-01T23:59:59.000Z

170

Climate Signal Detection Using Wavelet Transform: How to Make a Time Series Sing  

Science Conference Proceedings (OSTI)

In this paper, the application of the wavelet transform (WT) to climate time series analyses is introduced. A tutorial description of the basic concept of WT compared with similar concepts used in music, is also provided. Using an analogy between ...

K-M. Lau; Hengyi Weng

1995-12-01T23:59:59.000Z

171

Forecasting of preprocessed daily solar radiation time series using neural networks  

SciTech Connect

In this paper, we present an application of Artificial Neural Networks (ANNs) in the renewable energy domain. We particularly look at the Multi-Layer Perceptron (MLP) network which has been the most used of ANNs architectures both in the renewable energy domain and in the time series forecasting. We have used a MLP and an ad hoc time series pre-processing to develop a methodology for the daily prediction of global solar radiation on a horizontal surface. First results are promising with nRMSE {proportional_to} 21% and RMSE {proportional_to} 3.59 MJ/m{sup 2}. The optimized MLP presents predictions similar to or even better than conventional and reference methods such as ARIMA techniques, Bayesian inference, Markov chains and k-Nearest-Neighbors. Moreover we found that the data pre-processing approach proposed can reduce significantly forecasting errors of about 6% compared to conventional prediction methods such as Markov chains or Bayesian inference. The simulator proposed has been obtained using 19 years of available data from the meteorological station of Ajaccio (Corsica Island, France, 41 55'N, 8 44'E, 4 m above mean sea level). The predicted whole methodology has been validated on a 1.175 kWc mono-Si PV power grid. Six prediction methods (ANN, clear sky model, combination..) allow to predict the best daily DC PV power production at horizon d + 1. The cumulated DC PV energy on a 6-months period shows a great agreement between simulated and measured data (R{sup 2} > 0.99 and nRMSE < 2%). (author)

Paoli, Christophe; Muselli, Marc; Nivet, Marie-Laure [University of Corsica, CNRS UMR SPE, Corte (France); Voyant, Cyril [University of Corsica, CNRS UMR SPE, Corte (France); Hospital of Castelluccio, Radiotherapy Unit, Ajaccio (France)

2010-12-15T23:59:59.000Z

172

Characterization of nonlinear input-output systems using time series analysis  

Science Conference Proceedings (OSTI)

Data obtained from time series analysis has been used for a number of years for the characterization and response prediction of linear systems. This paper describes a time series technique for the analysis of nonlinear systems through the use of embeddings using delay coordinates or appropriate transformations of delay coordinates (local singular value decomposition or local canonical variate analysis). Local linear approaches are used to characterize the state evolution. Application of the technique is illustrated for a single degree of freedom oscillator with nonlinear stiffness, a mechanical chaos beam, and a climatic data time series. In each application analysis from measured data is emphasized. State rank, lyapunov exponents, and expected iterated prediction errors are quantified. The technique illustrated should be useful in the analysis of many forms of experimental data, especially where the state rank is not excessively large. 8 refs., 6 figs.

Hunter, N.F.; Theiler, J.

1991-01-01T23:59:59.000Z

173

A new measure of phase synchronization for a pair of time series and seizure focus localization  

E-Print Network (OSTI)

Defining and measuring phase synchronization in a pair of nonlinear time series are highly nontrivial. This can be done with the help of Fourier transform, when it exists, for a pair of stored (hence stationary) signals. In a time series instantaneous phase is often defined with the help of Hilbert transform. In this paper phase of a time series has been defined with the help of Fourier transform. This gives rise to a deterministic method to detect phase synchronization in its most general form between a pair of time series. Since this is a stricter method than the statistical methods based on instantaneous phase, this can be used for lateralization and source localization of epileptic seizures with greater accuracy. Based on this method a novel measure of phase synchronization, called syn function, has been defined, which is capable of quantifying neural phase synchronization and asynchronization as important parameters of epileptic seizure dynamics. It has been shown that such a strict measure of phase synchronization has potential application in seizure focus localization from scalp electroencephalogram (EEG) data, without any knowledge of electrical conductivity of the head.

Kaushik Majumdar

2006-12-13T23:59:59.000Z

174

Automatic Mapping of Social Networks of Actors from Text Corpora: Time Series Analysis  

Science Conference Proceedings (OSTI)

To illustrate the WORDij approach to automatic social network identification from large volumes of text, this research mined the social networks among President Clintons cabinet members (n=24)and also President G.W. Bushs cabinet members ... Keywords: Time Series Data Mining

James A. Danowski; Noah T. Cepela

2009-07-01T23:59:59.000Z

175

An automated pipeline for asteroseismology based on the autocorrelation of stellar time series  

E-Print Network (OSTI)

The autocorrelation of an asteroseismic time series has been identified as a powerful tool capable of providing measurements of the large frequency separations. The performance of this method has been assessed and quantified by Mosser & Appourchaux (2009). We propose now an automated pipeline based on it and describe its performance.

Mosser, Benoit

2010-01-01T23:59:59.000Z

176

Unraveling complex temporal associations in cellular systems across multiple time-series microarray datasets  

Science Conference Proceedings (OSTI)

Unraveling the temporal complexity of cellular systems is a challenging task, as the subtle coordination of molecular activities cannot be adequately captured by simple mathematical concepts such as correlation. This paper addresses the challenge with ... Keywords: Complex temporal association, Time-series microarray data

Wenyuan Li; Min Xu; Xianghong Jasmine Zhou

2010-08-01T23:59:59.000Z

177

The multi-agent system for prediction of financial time series  

Science Conference Proceedings (OSTI)

To take into account different character of distinct segments of non-stationary financial time series the multi-agent system based forecasting algorithm is suggested. The primary goal of present paper is to introduce methodological findings that could ... Keywords: classification, dimensionality, forecasting, sliding window, training

ar?nas Raudys; Indre Zliobaite

2006-06-01T23:59:59.000Z

178

Recognising Visual Patterns to Communicate Gas Turbine Time-Series Data  

E-Print Network (OSTI)

Recognising Visual Patterns to Communicate Gas Turbine Time-Series Data Jin Yu, Jim Hunter, Ehud analogue channels are sampled once per second and archived by the Tiger system for monitoring gas turbines that it is very important to identify such patterns in any attempt at summarisation. In the gas turbine domain

Reiter, Ehud

179

Chaotic Time Series Forecasting Base on Fuzzy Adaptive PSO for Feedforward Neural Network Training  

Science Conference Proceedings (OSTI)

Short-term electricity demand forecasting for the next hour to several days out is one of the most important tools by which an electric utility plans and dispatches the loading of generating units in order to meet system demand. But there exists chaos ... Keywords: Particle Swarm Optimization (PSO), chaotic time Series, fuzzy system, feedforward neural network

Wenyu Zhang; Jinzhao Liang; Jianzhou Wang; Jinxing Che

2008-11-01T23:59:59.000Z

180

Generating English Summaries of Time Series Data Using the Gricean Maxims  

E-Print Network (OSTI)

, gas-turbine sensor readings, and hospital intensive care data. Our weather-forecast generator users. Categories and Subject Descriptors I.2.7 [Natural Language Processing]: Language Generation. Keywords Time series data, Summarization, Natural Language Processing, Gricean maxims. 1. INTRODUCTION

Sripada, Yaji

Note: This page contains sample records for the topic "time series models" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Data Mining of Coal Mining Gas Time Series and Knowledge Discovery  

Science Conference Proceedings (OSTI)

Use the data mining techniques to discover the regularity knowledge from the gas sensor monitoring history database is very important approach for the supervisors to identify the reason causing the exceptional fluctuation automatically and make the correct ... Keywords: data mining, time series, clustering, shape measure, knowledge discovery

Shisong Zhu; Yunjia Wang; Lifang Kong

2011-10-01T23:59:59.000Z

182

BN-97-4-4 (RP-875) The Radiant Time Series Cooling  

E-Print Network (OSTI)

, Ph.D., P.E. Member ASHRAE Daniel E. Fisher, Ph.D. Member ASHRAE Curtis O. Pedersen, Ph.D. Fellow ASHRAE ABSTRACT Theradiant time series methodis a newmethodfor per- forming design cooling load, Inc. (www.ashrae.org). P

183

A visual analytics approach for peak-preserving prediction of large seasonal time series  

Science Conference Proceedings (OSTI)

Time series prediction methods are used on a daily basis by analysts for making important decisions. Most of these methods use some variant of moving averages to reduce the number of data points before prediction. However, to reach a good prediction ...

M. C. Hao; H. Janetzko; S. Mittelstdt; W. Hill; U. Dayal; D. A. Keim; M. Marwah; R. K. Sharma

2011-06-01T23:59:59.000Z

184

Matching pursuit by undecimated discrete wavelet transform for non-stationary time series of arbitrary length  

Science Conference Proceedings (OSTI)

We describe how to formulate a matching pursuit algorithm which successively approximates a periodic non-stationary time series with orthogonal projections onto elements of a suitable dictionary. We discuss how to construct such dictionaries derived ... Keywords: Discrete wavelet transform, matching pursuit, undecimated discrete wavelet transform

A. T. Walden; A. Contreras Cristan

1998-08-01T23:59:59.000Z

185

Time Series Measurements from a Moored Fluorescence-Based Dissolved Oxygen Sensor  

Science Conference Proceedings (OSTI)

We present an analysis of time-series measurements from a prototype fluorescence-quenching dissolved oxygen sensor moored for a six-day period in late March 1987 at 100 m depth in Saanich Inlet, British Columbia. Temporal variations in dissolved ...

Richard E. Thomson; Terrence A. Curran; M. Coreen Hamilton; Ronald McFarlane

1988-10-01T23:59:59.000Z

186

Dynamics in the Deep Canada Basin, Arctic Ocean, Inferred by Thermistor Chain Time Series  

Science Conference Proceedings (OSTI)

A 50-day time series of high-resolution temperature in the deepest layers of the Canada Basin in the Arctic Ocean indicates that the deep Canada Basin is a dynamically active environment, not the quiet, stable basin often assumed. Vertical ...

M-L. Timmermans; H. Melling; L. Rainville

2007-04-01T23:59:59.000Z

187

Measurements of time average series resonance effect in capacitively coupled radio frequency discharge plasma  

Science Conference Proceedings (OSTI)

Self-excited plasma series resonance is observed in low pressure capacitvely coupled radio frequency discharges as high-frequency oscillations superimposed on the normal radio frequency current. This high-frequency contribution to the radio frequency current is generated by a series resonance between the capacitive sheath and the inductive and resistive bulk plasma. In this report, we present an experimental method to measure the plasma series resonance in a capacitively coupled radio frequency argon plasma by modifying the homogeneous discharge model. The homogeneous discharge model is modified by introducing a correction factor to the plasma resistance. Plasma parameters are also calculated by considering the plasma series resonances effect. Experimental measurements show that the self-excitation of the plasma series resonance, which arises in capacitive discharge due to the nonlinear interaction of plasma bulk and sheath, significantly enhances both the Ohmic and stochastic heating. The experimentally measured total dissipation, which is the sum of the Ohmic and stochastic heating, is found to increase significantly with decreasing pressure.

Bora, B.; Bhuyan, H.; Favre, M.; Wyndham, E.; Chuaqui, H. [Facultad de Fisica, Pontificia Universidad Catolica de Chile, Ave. Vicuna Mackenna 4860, Santiago 22 (Chile); Kakati, M. [Thermal Plasma Processed Materials Laboratory, Centre of Plasma Physics, Institute for Plasma Research, Sonapur 782 402, Assam (India)

2011-10-15T23:59:59.000Z

188

Development of periodic response factors for use with the radiant time series method  

SciTech Connect

Harris and McQuiston (1988) developed conduction transfer function (CTF) coefficients corresponding to 41 representative wall assemblies and 42 representative roof assemblies for use with the transfer function method (TFM). They also developed a grouping procedure that allows design engineers to determine the correct representative wall or roof assembly that most closely matches a specific wall or roof assembly. The CTF coefficients and the grouping procedure have been summarized in the ASHRAE Handbook--Fundamentals (1989, 1993, 1997) and the ASHRAE Cooling and Heating Load Calculation Manual, second edition. More recently, a new, simplified design cooling load calculation procedure, the radiant time series method (RTSM), has been developed. The RTSM uses periodic response factors to model transient conductive heat transfer. While not a true manual load calculation procedure, it is quite feasible to implement the RTSM in a spreadsheet. To be useful in such an environment, it would be desirable to have a pre-calculated set of periodic response factors. Accordingly, a set of periodic response factors has been calculated and is presented in this paper.

Spitler, J.D.; Fisher, D.E.

1999-07-01T23:59:59.000Z

189

Time series analysis of AERI radiances for GCM testing and improvement  

NLE Websites -- All DOE Office Websites (Extended Search)

Time series analysis of AERI radiances for GCM testing and improvement Time series analysis of AERI radiances for GCM testing and improvement Dykema, John Harvard University Leroy, Stephen Harvard University Anderson, James Harvard University Tobin, David University of Wisconsin-Madison Knuteson, Robert University Of Wisconsin Revercomb, Henry University of Wisconsin-Madison Category: Radiation High resolution infrared radiances measured by the Atmospheric Emitted Radiance Interferometer (AERI) contained detailed information about the structure and dynamics of temperature, water vapor, and clouds below 3 km. Infrared radiances also contain the signature of radiative forcing by well-mixed gases that constitutes the greenhouse effect. Direct comparison of these radiance observations to similar radiances calculated from output

190

An approach to generating summaries of time series data in the gas turbine domain  

E-Print Network (OSTI)

In this paper, we propose an approach to generating summaries of time series data in the gas turbine domain using AI techniques. Through the think-aloud method with the aid of visualization of temporal data using time series workbench (TSW), both domain knowledge from experts about how to solve problems in the gas turbine and information about how domain experts analyze the archived temporal data are gotten. An algorithm to select interesting events is proposed and a prototype knowledge-based system is designed to generate summary of temporal data for interesting events in the gas turbine domain. Some further research works also are pointed. Key words: knowledge acquisition, knowledge-based system, gas turbine. 1

Jin Yu; Jim Hunter; Ehud Reiter; Somayajulu Sripada

2001-01-01T23:59:59.000Z

191

Bayesian and non-Bayesian mixture paradigms for clustering multivariate data : time series synchrony tests.  

E-Print Network (OSTI)

??During the last few years, the use of the finite mixture model has increased in the study of heterogeneous populations including its use in time (more)

Kim, Susan

2011-01-01T23:59:59.000Z

192

Towards Integrated Verification of Timed Transition Models  

Science Conference Proceedings (OSTI)

This paper describes an attempt to combine theorem proving and model-checking to formally verify real-time systems in a discrete time setting. The Timed Automata Modeling Environment (TAME) has been modified to provide a formal model for Time Transition ... Keywords: PVS, Real-time, SAL, equivalence verification, model reduction, model-checking, theorem proving

Mark Lawford; Vera Pantelic; Hong Zhang

2006-04-01T23:59:59.000Z

193

On Modeling and Forecasting Time Series of Smooth Curves  

E-Print Network (OSTI)

/fertility rate curves (Hyndman and Ullah, 2007; Erbas et al., 2007). Other examples include electricity system the rates are unobservable; hence one needs to forecast future rate profiles based on historical call of telephone customer service centers, where forecasts of daily call arrival rate profiles are needed

Shen, Haipeng

194

Time series models with an EGB2 conditional distribution  

E-Print Network (OSTI)

; ut = p 2 j#15;tj #0; 1 and, when #24; = & !1; ut = #15;2t #0; 1: Figure 7 compares the way observations are weighted by the score of a EGB2 distribution with #24; = & = 0:5; a Student?s t7 distribution and a GED(1:148). These are the same... (39) by #15;t gives a bounded function as j#15;tj ! 1: The following result, which is related to Lemma 1 of Harvey (2013, p23), is useful for deriving the asymptotic properties of the maximum likelihood estimator. Proposition 3 If #15;t #24; EGB2(0; 1...

Harvey, Andrew; Caivano, Michele

2013-07-17T23:59:59.000Z

195

Univariate Modeling and Forecasting of Monthly Energy Demand Time Series  

E-Print Network (OSTI)

in this report. #12;i ABSTRACT These electricity demand forms and instructions ask load-serving entities and Instructions for Electricity Demand Forecasts. California Energy Commission, Electricity Supply Analysis.................................................................................................................................7 Form 1 Historic and Forecast Electricity Demand

Abdel-Aal, Radwan E.

196

Computer system performance problem detection using time series models  

Science Conference Proceedings (OSTI)

Computer systems require monitoring to detect performance anomalies such as runaway processes, but problem detection and diagnosis is a complex task requiring skilled attention. Although human attention was never ideal for this task, as networks of computers ...

Peter Hoogenboom; Jay Lepreau

1993-06-01T23:59:59.000Z

197

RELATING TIME SERIES IN DATA TO SPATIAL VARIATION IN THE RESERVOIR USING WAVELETS  

E-Print Network (OSTI)

regression in the wavelet domains of both time and space. Wavelet transforms have the ability to reveal important events in time signals or spatial images. Thus we transformed both the model space and the time a subset of wavelet coefficients from each of the transformed domains. These subsets were used subsequently

198

A test for second order stationarity of a time series based on the Discrete Fourier Transform -Technical report  

E-Print Network (OSTI)

A test for second order stationarity of a time series based on the Discrete Fourier Transform stationary. Exploiting this important property, we construct a Portmanteau type test statistic for testing stationarity of the time series. It is shown that under the null of stationarity, the test statistic has

Subba Rao, Suhasini

199

A novel statistical time-series pattern based interval forecasting strategy for activity durations in workflow systems  

Science Conference Proceedings (OSTI)

Forecasting workflow activity durations is of great importance to support satisfactory QoS in workflow systems. Traditionally, a workflow system is often designed to facilitate the process automation in a specific application domain where activities ... Keywords: Activity duration, Interval forecasting, Statistical time series, Time-series patterns, Workflow system

Xiao Liu; Zhiwei Ni; Dong Yuan; Yuanchun Jiang; Zhangjun Wu; Jinjun Chen; Yun Yang

2011-03-01T23:59:59.000Z

200

A novel approach for estimation of optimal embedding parameters of nonlinear time series by structural learning of neural network  

Science Conference Proceedings (OSTI)

In this work a novel approach for estimation of embedding parameters for reconstruction of underlying dynamical system from the observed nonlinear time series by a feedforward neural network with structural learning is proposed. The proposed scheme of ... Keywords: Chaos, Embedding parameters, Embedding theorem, Neural network, Nonlinear time series, Strange attractor, Structural learning

Yusuke Manabe; Basabi Chakraborty

2007-03-01T23:59:59.000Z

Note: This page contains sample records for the topic "time series models" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

The physiology analysis system: An integrated approach for warehousing, management and analysis of time-series physiology data  

Science Conference Proceedings (OSTI)

The physiology analysis system (PAS) was developed as a resource to support the efficient warehousing, management, and analysis of physiology data, particularly, continuous time-series data that may be extensive, of variable quality, and distributed ... Keywords: Data base management system, Data display, Medical informatics, Physiology, Time-series data analysis

Thomas M. McKenna; Gagandeep Bawa; Kamal Kumar; Jaques Reifman

2007-04-01T23:59:59.000Z

202

Use of WindSat to Extend a Microwave-Based Daily Optimum Interpolation Sea Surface Temperature Time Series  

Science Conference Proceedings (OSTI)

The NOAA daily optimum interpolation sea surface temperature analysis (DOISST) is available either as a 31-yr (from 1981 onward) time series based on Advanced Very High Resolution Radiometer (AVHRR) observations or as a 9-yr (200211) time ...

Viva F. Banzon; Richard W. Reynolds

2013-04-01T23:59:59.000Z

203

A Time Series Analysis of Food Price and Its Input Prices  

E-Print Network (OSTI)

Rapid increases in consumer food price beginning in 2007 generated interest in identifying the main factors influencing these increases. In subsequent years, food prices have fluctuated, but generally have continued their ascent. The effects of crude oil, gasoline, corn, and ethanol prices, as well as, the relative foreign exchange rate of the U.S. dollar and producer price indexes for food manufacturing and fuel products on domestic food prices are examined. Because the data series are non-stationary and cointegrated, a vector error correction model is estimated. Weak exogeneity and exclusion tests in the cointegration space are performed. Directed acyclical graphs are used to specify contemporaneous causal relationships. Dynamic interactions among the series are given by impulse response functions and forecast error variance decompositions. Weak exogeneity tests indicate all eight series work to bring the system back into equilibrium following a shock to the system. Further, exclusion tests suggest crude oil, gasoline, food CPI, ethanol, and food PPI variables are not in the long-run relationships. Dynamic analyses suggest the following relationships. Ethanol price is not a major factor in domestic food prices, suggesting that food prices are largely unaffected by the recent increased use of corn-based ethanol for fuel. Crude oil prices, corn prices, and the relative foreign exchange rate of the U.S. dollar, however, do influence domestic food prices with corn price contributing the most to food price variability. Innovation accounting inferences are robust to potential different contemporaneous causal specifications.

Routh, Kari 1988-

2012-12-01T23:59:59.000Z

204

Transportation Energy Futures Series: Vehicle Technology Deployment Pathways: An Examination of Timing and Investment Constraints  

SciTech Connect

Scenarios of new vehicle technology deployment serve various purposes; some will seek to establish plausibility. This report proposes two reality checks for scenarios: (1) implications of manufacturing constraints on timing of vehicle deployment and (2) investment decisions required to bring new vehicle technologies to market. An estimated timeline of 12 to more than 22 years from initial market introduction to saturation is supported by historical examples and based on the product development process. Researchers also consider the series of investment decisions to develop and build the vehicles and their associated fueling infrastructure. A proposed decision tree analysis structure could be used to systematically examine investors' decisions and the potential outcomes, including consideration of cash flow and return on investment. This method requires data or assumptions about capital cost, variable cost, revenue, timing, and probability of success/failure, and would result in a detailed consideration of the value proposition of large investments and long lead times. This is one of a series of reports produced as a result of the Transportation Energy Futures (TEF) project, a Department of Energy-sponsored multi-agency effort to pinpoint underexplored strategies for abating GHGs and reducing petroleum dependence related to transportation.

Plotkin, S.; Stephens, T.; McManus, W.

2013-03-01T23:59:59.000Z

205

Investigation of flood inundation on playas within the Zone of Chotts, using a time-series of AVHRR  

E-Print Network (OSTI)

Our principal objectives were to examine the application of a time-series of advanced very high-resolution radiometer (AVHRR) data to contrast the inundation regimes of a range of large, climatically sensitive playas in the Zone of Chotts regions of southern Tunisia and northeastern Algeria. In doing so, we aimed to: (i) refine methods for monitoring monthly changes in lake areas and seasonal water balance, building from previous studies; (ii) explore the extent to which simple hydrological models can be developed for individual playas; and (iii) compare the hydrologic response of individual playas to seasonal rainfall inputs within North Africa. Here, analyses were conducted using two time-series of AVHRR data (c.2 images per month) for southern Tunisia and northern Algeria (1983 -- 1993 and 1987 -- 1999), with coincident meteorological data. These data were used to detect and monitor inundation events within specific playa catchments in the Zone of Chotts region. Key analyses methods included: (a) the use of reflectance profiles for each time-series to infer inundation processes for each playa and (b) the extraction of lake areas from sequential image data to determine the extent of inundation with an accuracy of between 2% and 6% (depending on lake size). For those playas which were found to inundate as a direct result of precipitation records of lake area change were used to drive simple hydrological models to allowed mean monthly precipitation ( P), monthly effective precipitation (P-E), and monthly evaporation (E) to be estimated. The techniques presented here make an important contribution to our understanding of the hydrology of playas in this region. Results for individual playas also suggest that these techniques may be useful in highlighting the dynamic respo...

Bryant Rainey Department; R. G. Bryant; M. P. Rainey

2002-01-01T23:59:59.000Z

206

Interpretation of engine cycle-to-cycle variation by chaotic time series analysis  

DOE Green Energy (OSTI)

In this paper we summarize preliminary results from applying a new mathematical technique -- chaotic time series analysis (CTSA) -- to cylinder pressure data from a spark-ignition (SI) four-stroke engine fueled with both methanol and iso-octane. Our objective is to look for the presence of deterministic chaos'' dynamics in peak pressure variations and to investigate the potential usefulness of CTSA as a diagnostic tool. Our results suggest that sequential peak cylinder pressures exhibit some characteristic features of deterministic chaos and that CTSA can extract previously unrecognized information from such data. 18 refs., 11 figs., 2 tabs.

Daw, C.S.; Kahl, W.K.

1990-01-01T23:59:59.000Z

207

Use of Long Time-series ACRF Measurements to Improve Data Quality Analysis  

NLE Websites -- All DOE Office Websites (Extended Search)

2, 2008 2, 2008 Eighteenth ARM Science Team Meeting 1 Use of Long Time-Series ACRF Measurements to Improve Data Quality Analysis Sean Moore Mission Research and Technical Services Santa Barbara, CA ARM Data Quality Office University of Oklahoma Norman, OK March 12, 2008 Eighteenth ARM Science Team Meeting 2 ARM Data Quality Office Full Time Staff *Ken Kehoe *Randy Peppler *Karen Sonntag *Justin Monroe Student Analysts *Nathan Hiers (Sr) *Stephen Mullens (Sr) *Kimberly Rabon (Jr) *Lacey Evans (Jr) ARM Data Quality Office, National Weather Center The University of Oklahoma, Norman, OK Sean Moore Mission Research and Technical Services Santa Barbara, CA March 12, 2008 Eighteenth ARM Science Team Meeting 3 Daily Quality Checks * Automated software checks every measurement for outliers against some pre-defined limits.

208

Shock timing on the National Ignition Facility: the first precision tuning series  

Science Conference Proceedings (OSTI)

Ignition implosions on the National Ignition Facility (NIF) [Lindl et al., Phys. Plasmas 11, 339 (2004)] are driven with a very carefully tailored sequence of four shock waves that must be timed to very high precision in order to keep the fuel on a low adiabat. The first series of precision tuning experiments on NIF have been performed. These experiments use optical diagnostics to directly measure the strength and timing of all four shocks inside the hohlraum-driven, cryogenic deuterium-filled capsule interior. The results of these experiments are presented demonstrating a significant decrease in the fuel adiabat over previously un-tuned implosions. The impact of the improved adiabat on fuel compression is confirmed in related deuterium-tritium (DT) layered capsule implosions by measurement of fuel areal density (rR), which show the highest fuel compression (rR {approx} 1.0 g/cm{sup 2}) measured to date.

Robey, H F; Celliers, P M; Kline, J L; Mackinnon, A J

2011-10-27T23:59:59.000Z

209

Double Quantization of the Regressor Space for Long-Term Time Series Prediction: Method and Proof of Stability  

E-Print Network (OSTI)

on a stan- dard benchmark (Santa Fe A series) and on a real-world problem of electrical load forecasting an electrical consumption, the prob- lem may be to forecast hourly values for a whole day instead of predicting, a particular time series forecasting method based on Kohonen maps is described. This method has been

Paris-Sud XI, Université de

210

Time Series Photometry of Variable Stars in the Globular Cluster NGC 6397  

E-Print Network (OSTI)

Time series BVI photometry is presented for 16 short-period variables located in the central region of the globular cluster NGC 6397. The sample includes 9 newly detected variables. The light curve of cataclysmic variable CV6 shows variability with a period of 0.2356 days. We confirm an earlier reported period of 0.472 days for cataclysmic variable CV1. Phased light curves of both CVs exhibit sine-like light curves, with two minima occurring during each orbital cycle. The secondary component of CV1 has a low average density of 0.83 g/cm^{3} indicating that it cannot be a normal main sequence star. Variables among the cluster blue stragglers include a likely detached eclipsing binary with orbital period of 0.787 days, three new SX Phe stars (one of which has the extremely short period of 0.0215 days), and three low amplitude variables which are possible gamma Doradus variables.

Janusz Kaluzny; Ian B. Thompson

2002-10-29T23:59:59.000Z

211

A Double Fourier Series (DFS) Dynamical Core in a Global Atmospheric Model with Full Physics  

Science Conference Proceedings (OSTI)

This study describes an application of the double Fourier series (DFS) spectral method developed by Cheong as an alternative dynamical option in a model system that was ported into the Global/Regional Integrated Model System (GRIMs). A message ...

Hoon Park; Song-You Hong; Hyeong-Bin Cheong; Myung-Seo Koo

2013-09-01T23:59:59.000Z

212

A Double Fourier Series (DFS) Dynamic Core in a Global Atmospheric Model with Full Physics  

Science Conference Proceedings (OSTI)

This study describes an application of the double Fourier series (DFS) spectral method developed by Cheong (2006) as an alternative dynamic option in a model system that was ported in the Global/Regional Integrated Model system (GRIMs). A message-...

Hoon Park; Song-You Hong; Hyeong-Bin Cheong; Myung-Seo Koo

213

The ups and downs of the renormalization group applied to financial time series  

E-Print Network (OSTI)

Starting from inhomogeneous time scaling and linear decorrelation between successive price returns, Baldovin and Stella recently devised a model describing the time evolution of a financial index. We first make it fully explicit by using Student distributions instead of power law-truncated Levy distributions; we also show that the analytic tractability of the model extends to the larger class of symmetric generalized hyperbolic distributions and provide a full computation of their multivariate characteristic functions. The Baldovin and Stella model, while mimicking well volatility relaxation phenomena such as the Omori law, fails to reproduce other stylized facts such as the leverage effect or some time reversal asymmetries. We discuss how to modify the dynamics of this process in order to reproduce real data more accurately.

Challet, Damien

2008-01-01T23:59:59.000Z

214

Low-Frequency Modulation of Turbulent Diapycnal Mixing by Anticyclonic Eddies Inferred from the HOT Time Series  

Science Conference Proceedings (OSTI)

Profiles of potential density obtained from CTD measurements during the Hawaii Ocean Time series (HOT) program in the vicinity of the island of Oahu, Hawaii, are used to evaluate low-frequency variability of turbulent kinetic dissipation rates ...

Zhao Jing; Lixin Wu

2013-04-01T23:59:59.000Z

215

Time Series of Daily Averaged Cloud Fractions over Landfast First-Year Sea Ice from Multiple Data Sources  

Science Conference Proceedings (OSTI)

The time series of daily averaged cloud fractions (CFs) collected from different platformstwo Moderate Resolution Imaging Spectroradiometer (MODIS) instruments on Terra and Aqua satellites, the National Centers for Environmental Prediction (NCEP)...

Xin Jin; John M. Hanesiak; David G. Barber

2007-11-01T23:59:59.000Z

216

Aging in coherent noise models and natural time  

Science Conference Proceedings (OSTI)

Event correlation between aftershocks in the coherent noise model is studied by making use of natural time, which has recently been introduced in complex time-series analysis. It is found that the aging phenomenon and the associated scaling property discovered in the observed seismic data are well reproduced by the model. It is also found that the scaling function is given by the q-exponential function appearing in nonextensive statistical mechanics, showing power-law decay of event correlation in natural time.

Tirnakli, Ugur; Abe, Sumiyoshi [Department of Physics, Faculty of Science, Ege University, 35100 Izmir (Turkey); Institute of Physics, University of Tsukuba, Ibaraki 305-8571 (Japan)

2004-11-01T23:59:59.000Z

217

Creating Synthetic Wind Speed Time Series for 15 New Zealand Wind Farms  

Science Conference Proceedings (OSTI)

Wind data at time scales from 10 min to 1 h are an important input for modeling the performance of wind farms and their impact on many countries national electricity systems. Planners need long-term realistic (i.e., meteorologically spatially and ...

Richard Turner; Xiaogu Zheng; Neil Gordon; Michael Uddstrom; Greg Pearson; Rilke de Vos; Stuart Moore

2011-12-01T23:59:59.000Z

218

Model 1931/2931 Series Single and Dual-Channel Optical Meters  

E-Print Network (OSTI)

Model 1931/2931 Series Single and Dual-Channel Optical Meters User's Manual #12;ii Preface #12;iii/2931-C Series Optical Meters optimized for your applications, Newport will on occasion update existing ................................................................................ 21 2.2 Optical Meter Functionality ....................................................... 22 2

Kleinfeld, David

219

Model 1936/2936-C Series Single and Dual-Channel Optical Meters  

E-Print Network (OSTI)

Model 1936/2936-C Series Single and Dual-Channel Optical Meters User's Manual #12;2 Preface #12 to keep the 1936/2936 Series Optical Meters optimized for your applications, Newport will on occasion ................................................................................ 25 2.2 Optical Meter Functionality ....................................................... 26 2

Kleinfeld, David

220

Anomaly detection in noisy and irregular time series: the "turbodiesel charging pressure" case study  

Science Conference Proceedings (OSTI)

In this paper we consider the problem of detecting anomalies in sample series obtained from critical train subsystems. Our study is the analysis of charging pressure in turbodiesel engines powering a fleet of passenger trains. We describe an automated ...

Anah Balbi; Michael Provost; Armando Tacchella

2010-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "time series models" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

A New Series of Rate Decline Relations Based on the Diagnosis of Rate-Time Data  

E-Print Network (OSTI)

The so-called "Arps" rate decline relations are by far the most widely used tool for assessing oil and gas reserves from rate performance. These relations (i.e., the exponential and hyperbolic decline relations) are empirical where the starting point for their derivation is given by the definitions of the "loss ratio" and the "derivative of the loss ratio", where the "loss ratio" is the ratio of rate data to derivative of rate data, and the "derivative of the loss ratio" is the "b-parameter" as defined by Arps [1945]. The primary goal of this work is the interpretation of the b-parameter continuously over time and thus the better understanding of its character. As is shown below we propose "monotonically decreasing functional forms" for the characterization of the b-parameter, in addition to the exponential and hyperbolic rate decline relations, where the b-parameter is assumed to be zero and constant, respectively. The proposed equations are as follow: b(t)=constant (Arps' hyperbolic rate-decline relation), []tbbtb10exp)(-bt= (exponential function), (power-law function), 10)(btbtb=)/(1)(10tbbtb+= (rational function). The corresponding rate decline relation for each case is obtained by solving the differential equation associated with the selected functional for the b-parameter. The next step of this procedure is to test and validate each of the rate decline relations by applying them to various numerical simulation cases (for gas), as well as for field data cases obtained from tight/shale gas reservoirs. Our results indicate that b-parameter is never constant but it changes continuously with time. The ultimate objective of this work is to establish each model as a potential analysis/diagnostic relation. Most of the proposed models yield more realistic estimations of gas reserves in comparison to the traditional Arps' rate decline relations (i.e., the hyperbolic decline) where the reserves estimates are inconsistent and over-estimated. As an example, the rational b-parameter model seems to be the most accurate model in terms of representing the character of rate data; and therefore, should yield more realistic reserves estimates. Illustrative examples are provided for better understanding of each b-parameter rate decline model. The proposed family of rate decline relations was based on the character of the b-parameter computed from the rate-time data and they can be applied to a wide range of data sets, as dictated by the character of rate data.

Boulis, Anastasios

2009-08-01T23:59:59.000Z

222

Trend Estimation and Regression Analysis in Climatological Time Series: An Application of Structural Time Series Models and the Kalman Filter  

Science Conference Proceedings (OSTI)

The detection of trends in climatological data has become central to the discussion on climate change due to the enhanced greenhouse effect. To prove detection, a method is needed (i) to make inferences on significant rises or declines in trends, ...

H. Visser; J. Molenaar

1995-05-01T23:59:59.000Z

223

Analysis of SWADE Discus N Wind Speed and Wave Height Time Series. Part II: Quantitative Growth Rates during a Storm  

Science Conference Proceedings (OSTI)

In Part I, wind speed and wave height time series obtained from the Discus N buoy during two storm events recorded in the SWADE experiment were analyzed using discrete wavelet packet transforms. One result of the analysis is that distinct tightly ...

Jorge F. Willemsen

1997-06-01T23:59:59.000Z

224

Analysis of SWADE Discus N Wind Speed and Wave Height Time Series. Part I: Discrete Wavelet Packet Representations  

Science Conference Proceedings (OSTI)

Discus N denotes a single buoy employed during the SWADE experiment, equipped to record wave amplitude and wind speed time series at a rate of 1 Hz. Over the course of approximately 4.5 days, two clear-cut examples of sea response to wind ...

Jorge E. Willemsen

1995-12-01T23:59:59.000Z

225

The estimation techniques of the time series correlations in nuclear reactor calculations by the Monte Carlo method using multiprocessor computers  

Science Conference Proceedings (OSTI)

The algorithms of estimation of the time series correlation functions in nuclear reactor calculations using the Monte Carlo method are described. Correlation functions are used for the estimation of biases, for calculations of variance taking into account the correlations between neutron generations, and for choosing skipped generations.

Kalugin, M. A.; Oleynik, D. S.; Sukhino-Khomenko, E. A., E-mail: sukhino-khomenko@adis.vver.kiae.ru [National Research Centre Kurchatov Institute (Russian Federation)

2012-12-15T23:59:59.000Z

226

Making Hand Geometry Verification System More Accurate Using Time Series Representation with R-K Band Learning  

E-Print Network (OSTI)

At present, applications of biometrics are rapidly increasing due to inconveniences in using traditional passwords and physical keys. Hand geometry, one of the most well-known biometrics, is implemented in many verification systems with various feature extraction methods. In recent work, a hand geometry verification system using time series conversion techniques and Dynamic Time Warping (DTW) distance measure with Sakoe-Chiba band has been proposed. This system demonstrates many advantages, especially ease of implementation and small storage space requirement using time series representation. In this paper, we propose a novel hand geometry verification system that exploits DTW distance measure and R-K band learning to further improve the system performance. Finally, our evaluation reveals that our proposed system outperforms the current system by a wide margin, in terms of False Acceptance Rate (FAR), False Rejection Rate (FRR), and Total Success Rate (TSR) at Equal Error Rate (EER).

Niennattrakul, Vit

2009-01-01T23:59:59.000Z

227

Modeling of ECM Controlled Series Fan-powered VAV Terminal Units  

E-Print Network (OSTI)

Semi-empirical models for series fan-powered variable air volume terminal units (FPTUs) were developed based on models of the primary, plenum, fan airflow and the fan power consumption. The experimental setups and test procedures were developed respectively for primary, plenum and fan airflow to test each component of the FPTUs at typical design pressures and airflows. Two sizes of the terminal units from three manufacturers were used in this study. All of the FPTUs were equipped with electronically commutated motors (ECM). Data provided by the models were compared against the data from previous experiments to prove the models validity. Regression modeling was performed by using SigmaStat. The model of primary airflow had an R2 above 0.948 for all the terminal units evaluated while the plenum airflow model had an R2 above 0.99. For all the terminal units, the R2 of the fan airflow model was ranged from 0.973 to 0.998. Except for one fan, the fan power consumption model was able to characterize the power performance and had an R2 above 0.986. By combining the airflow and power models, the model for series FPTU was developed. Verification was made to prove the FPTU models validity by comparing the measured and predicted data of airflow and power consumption. Correction factors were used in the primary airflow model to compensate for the difference caused by large measurement errors and the system effects. The predicted values were consistent with measurements and no offset was needed in the primary airflow model. Generally, the newly established model was able to describe the airflow performance as well as power consumption of series FPTUs without adding complexity.

Yin, Peng

2010-08-01T23:59:59.000Z

228

Testing and forecasting the time series of the solar activity by singular spectrum analysis  

E-Print Network (OSTI)

To study and forecast the solar activity data a quite perspective method of singular spectrum analysis (SSA) is proposed. As known, data of the solar activity are usually presented via the Wolf numbers associated with the effective amount of the sunspots. The advantages and disadvantages of SSA are described by its application to the series of the Wolf numbers. It is shown that the SSA method provides a sufficiently high reliability in the description of the 11-year solar cycle. Moreover, this method is appropriate for revealing more long cycles and forecasting the further solar activity during one and a half of 11-year cycle.

A. Loskutov; I. A. Istomin; K. M. Kuzanyan; O. L. Kotlyarov

2000-10-13T23:59:59.000Z

229

Advective Time Lags in Box Models  

Science Conference Proceedings (OSTI)

A box model of the thermohaline circulation with mixed boundary conditions in which advective processes are incorporated via an explicit time delay mechanism is considered. The pipes that connect the subtropical and subpolar boxes have a finite ...

Douglas A. Kurtze; Juan M. Restrepo

2001-07-01T23:59:59.000Z

230

Space, time and nesting Integrated Assessment Models  

Science Conference Proceedings (OSTI)

Integrated Assessment Modelling in the field of air pollution has advanced greatly since the 1985 Helsinki Protocol on the reduction of Sulphur emissions and their transboundary fluxes. With subsequent protocols and increased understanding of the inter-relationships ... Keywords: CLRTAP, Integrated Assessment Modelling, Scale, Science-policy interaction, Space, Time

T. Oxley; H. M. ApSimon

2007-12-01T23:59:59.000Z

231

Vector nonlinear time-series analysis of gamma-ray burst datasets on heterogeneous clusters  

Science Conference Proceedings (OSTI)

The simultaneous analysis of a number of related datasets using a single statistical model is an important problem in statistical computing. A parameterized statistical model is to be fitted on multiple datasets and tested for goodness of fit within ... Keywords: Data Analysis, Dynamic Load Balancing, Heterogeneous Computing

Ioana Banicescu; Ricolindo L. Cario; Jane L. Harvill; John Patrick Lestrade

2005-04-01T23:59:59.000Z

232

A genetic algorithm approach to the spectral estimation of time series with noise and missed observations  

Science Conference Proceedings (OSTI)

This study considers the problem of estimating the autoregressive moving average (ARMA) power spectral density when measurements are corrupted by noise and by missed observations. The missed observations model is based on a probabilistic structure. Unlike ... Keywords: ARMA model, Bernoulli modulation, Genetic algorithm, Missed observations, Spectral estimation

Jui-Chung Hung

2008-12-01T23:59:59.000Z

233

Statistical analysis of electrophoresis time series for improving basecalling in DNA sequencing  

Science Conference Proceedings (OSTI)

In automated DNA sequencing, the final algorithmic phase, referred to as basecalling, consists of the translation of four time signals in the form of peak sequences (electropherogram) to the corresponding sequence of bases. Commercial basecallers detect ...

Anna Tonazzini; Luigi Bedini

2007-07-01T23:59:59.000Z

234

Time series analysis of the lead-lag relationship of freight futures and spot market prices  

E-Print Network (OSTI)

This thesis analyzes the relationship between the physical and paper shipping markets. The main objective is to find if one market leads the other by a specific time period so that market players can take advantage from ...

Gavriilidis, Nikolaos

2008-01-01T23:59:59.000Z

235

Considerations of Meteorological Time Series in Estimating Regional-Scale Crop Yield  

Science Conference Proceedings (OSTI)

The sensitivity of simulated soybean yield to spatial averaging of meteorological data was analyzed for the central United States during a 23-year period. Regional yield was simulated using the physiological model, SOYGRO, in two sets of ...

Gregory J. Carbone

1993-08-01T23:59:59.000Z

236

Reconstructing Streamflow Time Series in Central Arizona Using Monthly Precipitation and Tree Ring Records  

Science Conference Proceedings (OSTI)

An adaptive, three-way interpolation model based on multiple discriminant analysis, multiple linear regression, and normal ratio methods was used to reconstruct streamflows for three gauges in central Arizona for the period from 1580, using ...

Kenneth C. Young

1994-03-01T23:59:59.000Z

237

Middle-term electrical load forecasting by time series decomposition. Report for EUNITE 2001 Competition, 2001. Available at http://neuron.tuke.sk/competition  

E-Print Network (OSTI)

Abstract. We present the results of our work in the frame of World-Wide Competition organized within the EUNITE network. For the middle-term electric load forecasting task with prediction horizon 1-31 days ahead we decided to develop a simple model based on decomposition of analyzed time series. The additive components were estimated using the training data collected by the Eastern Slovakian Electricity Corporation during the period 1997-1998. The model was validated by using of the real data from the first 20 days in December 1998. For final application the model was retrained and the requested forecasts were performed. The temperatures in January 1999, which form the inputs to the model, were estimated by moving average methods applied on historical data sets. 1

Emil Pelikn

2002-01-01T23:59:59.000Z

238

An Analysis of the INFFC Cotton Futures Time Series: Lower Bounds and Testbed Design Recommendations  

E-Print Network (OSTI)

forecasting ranging from option pricing (Hutchinson et al. [1994]), corporate bond rating (Moody and Utans. Consequently, financial markets forecasting models consider incomplete information, while factors not included]). A serious drawback in comparing different financial markets forecasting techniques is a lack of standard

Obradovic, Zoran

239

Spatial and temporal variations in streambed hydraulic conductivity quantified with time-series thermal methods  

E-Print Network (OSTI)

conductivity Streambed seepage Heat as a tracer Surface water­ground water interaction Pajaro River s u m m a r was 62 m3 s?1 , with most of the loss occurring along the lower part of the experimental reach. Point and with time, with greater seepage occurring along the lower part of the reach and during the summer and fall

Fisher, Andrew

240

An Approach to Generating Summaries of Time Series Data in the Gas Turbine Domain Jin Yu and Jim Hunter and Ehud Reiter and Somayajulu Sripada  

E-Print Network (OSTI)

An Approach to Generating Summaries of Time Series Data in the Gas Turbine Domain Jin Yu and Jim an approach to generating summaries of time series data in the gas turbine domain using AI techniques. Through), both domain knowledge from experts about how to solve problems in the gas turbine and information about

Sripada, Yaji

Note: This page contains sample records for the topic "time series models" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

A Stochastic Raindrop Time Distribution Model  

Science Conference Proceedings (OSTI)

A disdrometer simultaneously measuring time of arrival and size of raindrops was set up in the Paris, France, area. Data collected over a period of 25 months (May 1992 to May 1994) are presented and analyzed to derive a long-term temporal model ...

J. Lavergnat; P. Gol

1998-08-01T23:59:59.000Z

242

Fluorescence spectrum analysis using Fourier series modeling for Fluorescein solution in Ethanol  

E-Print Network (OSTI)

We have measured the fluorescence spectrum for fluorescein solution in ethanol with concentration 1 {\\times} 10-3 mol/liter at different temperatures from room temperature to freezing point of solvent, (T = 153, 183, 223, 253, and 303 K) using liquid nitrogen. Table curve 2D version 5.01 program has been used to determine the fitting curve and fitting equation for each fluorescence spectrum. Fourier series (3 {\\times} 2) was the most suitable fitting equation for all spectra. Theoretical fluorescence spectrum of fluorescein in ethanol at T = 183K was calculated and compared with experimental fluorescence spectrum at the same temperature. There is a good similarity between them.

Hadi, Mahasin F

2011-01-01T23:59:59.000Z

243

Stochastic modeling and global warming trend extraction for ocean acoustic travel times. Interim technical report  

SciTech Connect

A possible indication of the existence of global climate warming is a negative trend for the travel time of an acoustic pulse along a fixed long path, or paths, in the ocean over a period of many years. The goal of this report is the development of methods specifically for determining the presence of a long term trend for climate change from a temporal sequence of measurements of acoustic propagation times. Robust statistical methods for determining whether a significant trend is present in a given set of time series data have been developed and, for illustration, applied to some specific traveltime time series generated by the MASIG and GFDL ocean models. In this report we consider line + noise and ARIMA statistical models. We show that if the time series are long enough, somewhat over 20 years, then series such as those simulated by the MASIG and GFDL models can be classified reliably as line + noise when this is the case. However, it is shown that the results are considerably different for the two ocean models under consideration and that these models can not currently be relied upon by themselves to predict global warming. Experimental data is most certainly needed, not only to measure global warming itself, but to help improve the ocean model themselves.

Bottone, S.; Gray, H.L.; Woodward, W.A.

1995-01-06T23:59:59.000Z

244

Time management in a Poisson fishing model  

E-Print Network (OSTI)

The aim of the paper is to extend the model of "fishing problem". The simple formulation is following. The angler goes to fishing. He buys fishing ticket for a fixed time. There are two places for fishing at the lake. The fishes are caught according to renewal processes which are different at both places. The fishes' weights and the inter-arrival times are given by the sequences of i.i.d. random variables with known distribution functions. These distributions are different for the first and second fishing place. The angler's satisfaction measure is given by difference between the utility function dependent on size of the caught fishes and the cost function connected with time. On each place the angler has another utility functions and another cost functions. In this way, the angler's relative opinion about these two places is modeled. For example, on the one place better sort of fish can be caught with bigger probability or one of the places is more comfortable. Obviously our angler wants to have as much sati...

Karpowicz, Anna

2008-01-01T23:59:59.000Z

245

Time series association learning  

DOE Patents (OSTI)

This invention generally relates to machine-based speech and speaker recognition and, more particularly, to machine-based speech recognition using a learned relationship between acoustic and articulatory parameters. An acoustic input is recognized from inferred articulatory movements output by a learned relationship between training acoustic waveforms and articulatory movements. The inferred movements are compared with template patterns prepared from training movements when the relationship was learned to regenerate an acoustic recognition. In a preferred embodiment, the acoustic-articulatory relationships are learned by a neural network. Subsequent input acoustic patterns then generate the inferred articulatory movements for use with the templates. Articulatory movement data may be supplemented with characteristic acoustic information, e.g. relative power and high frequency data, to improve template recognition. 7 figs.

Papcun, G.J.

1990-01-31T23:59:59.000Z

246

Time series association learning  

DOE Patents (OSTI)

An acoustic input is recognized from inferred articulatory movements output by a learned relationship between training acoustic waveforms and articulatory movements. The inferred movements are compared with template patterns prepared from training movements when the relationship was learned to regenerate an acoustic recognition. In a preferred embodiment, the acoustic articulatory relationships are learned by a neural network. Subsequent input acoustic patterns then generate the inferred articulatory movements for use with the templates. Articulatory movement data may be supplemented with characteristic acoustic information, e.g. relative power and high frequency data, to improve template recognition.

Papcun, George J. (Santa Fe, NM)

1995-01-01T23:59:59.000Z

247

An Approach to Integrate a Space-Time GIS Data Model with High Performance Computers  

Science Conference Proceedings (OSTI)

In this paper, we describe an approach to integrate a Space-Time GIS data model on a high performance computing platform. The Space-Time GIS data model has been developed on a desktop computing environment. We use the Space-Time GIS data model to generate GIS module, which organizes a series of remote sensing data. We are in the process of porting the GIS module into an HPC environment, in which the GIS modules handle large dataset directly via parallel file system. Although it is an ongoing project, authors hope this effort can inspire further discussions on the integration of GIS on high performance computing platforms.

Wang, Dali [ORNL; Zhao, Ziliang [University of Tennessee, Knoxville (UTK); Shaw, Shih-Lung [ORNL

2011-01-01T23:59:59.000Z

248

Foundation for a time interval access control model  

Science Conference Proceedings (OSTI)

A new model for representing temporal access control policies is introduced. In this model, temporal authorizations are represented by time attributes associated with both subjects and objects, and a time interval access graph. The time ...

Francis B. Afinidad; Timothy E. Levin; Cynthia E. Irvine; Thuy D. Nguyen

2005-09-01T23:59:59.000Z

249

Timing modeling and optimization under the transmission line model  

E-Print Network (OSTI)

AbstractAs the operating frequency increases to gigahertz and the rise time of a signal is less than or comparable to the time-of-flight delay of a wire, it is necessary to consider the transmission line behavior for delay computation. We present in this paper, an analytical formula for the delay computation under the transmission line model. Extensive simulations with SPICE show the high fidelity of the formula. Compared with previous works, our model leads to smaller average errors in delay estimation. Based on this formula, we show the property that the minimum delay for a transmission line with reflection occurs when the number of round trips is minimized (i.e., equals one). Besides, we show that the delay of a circuit path is a posynomial function in wire and buffer sizes, implying that a local optimum is equal to the global optimum. Thus, we can apply any efficient search algorithm such as the well-known gradient search procedure to compute the globally optimal solution. Experimental results show that simultaneous wire and buffer sizing is very effective for performance optimization under the transmission line model. Index TermsBuffer sizing, delay model, inductance, interconnect, performance optimization, transmission line, wire sizing.

Tai-chen Chen; Song-ra Pan; Yao-wen Chang

2004-01-01T23:59:59.000Z

250

Continuous-time nonlinear model predictive control of time-delayed Wiener-type systems  

Science Conference Proceedings (OSTI)

This paper deals with a novel method of continuous-time model predictive control for nonlinear time-delayed systems. The problems regarding time delays are solved by incorporating delayed and undelayed model outputs in the control-law derivation. Nonlinear-mapping ... Keywords: Wiener-type model, continuous system, nonlinear predictive control, time-delayed system

Simon Oblak; Igor krjanc

2006-02-01T23:59:59.000Z

251

Capabilities Series  

NLE Websites -- All DOE Office Websites (Extended Search)

Capabilities Series Capabilities Series www.emsl.pnl.gov Scientific Innovation Through Integration WHY USE EMSL'S MOLECULAR SCIENCE COMPUTING CAPABILITY? Ì Molecular Science Computing provides users with an integrated suite of computing hardware and software capabilities optimized for achieving the fastest time-to-solution for complex systems-level environmental molecular science simulations. Ì Expert staff members have extensive knowledge and experience in high-performance computing, as well as the operations, domain expertise, and scientific knowledge to support EMSL's users. Ì Substantial integration of transformational high-end computing simulations with experimental resources at EMSL provides a unique multidisciplinary research environment. The Molecular Science Computing capability at EMSL

252

Adaptive time-frequency analysis based on autoregressive modeling  

Science Conference Proceedings (OSTI)

A new adaptive method for discrete time-frequency analysis based on autoregressive (AR) modeling is introduced. The performance of AR modeling often depends upon a good selection of the model order. The predictive least squares (PLS) principle of Rissanen ... Keywords: Adaptive filters, Autoregressive modeling, Least squares methods, Model order, Time-frequency analysis

Antonio H. Costa; Stephan Hengstler

2011-04-01T23:59:59.000Z

253

Modeling, simulation, and analysis of series hybrid electric vehicles for fuel economy improvement.  

E-Print Network (OSTI)

??A hybrid electric vehicle (HEV) combines a conventional internal combustion engine (ICE) propulsion system with an electric propulsion system. In a series HEV, an electric (more)

Khandaker, Masuma

2011-01-01T23:59:59.000Z

254

System Modeling and Energy Management Strategy Development for Series Hybrid Vehicles .  

E-Print Network (OSTI)

??A series hybrid electric vehicle is a vehicle that is powered by both an engine and a battery pack. An electric motor provides all of (more)

Cross, Patrick Wilson

2008-01-01T23:59:59.000Z

255

Bayesian dynamic models for space-time point processes  

Science Conference Proceedings (OSTI)

In this work we propose a model for the intensity of a space-time point process, specified by a sequence of spatial surfaces that evolve dynamically in time. This specification allows flexible structures for the components of the model, in order to handle ... Keywords: Bayesian inference, Disease mapping, Dynamic models, Integrated Laplace, Monte Carlo Markov chain, Space-time point processes

Edna A. Reis; Dani Gamerman; Marina S. Paez; Thiago G. Martins

2013-04-01T23:59:59.000Z

256

On the Probabilistic Modeling of Runway Inter-departure Times  

E-Print Network (OSTI)

This paperr examines the validity of the Erlang distribution for runway service times. It uses high-fidelity surface surveillance data, for the first time, to model the probability distributions of runway service times and ...

Balakrishnan, Hamsa

257

Fair SMG and Linear Time Model Checking  

E-Print Network (OSTI)

SMG is a system designed to generate a finite state model of a program from the program itself and an operational semantics for the programming language. This finite state model can then be model-checked to verify desired temporal properties of the original program. In this paper we first show how we have incorporated notions of fairness into SMG; in particular, a user is now able to define semantics with "fair" constructs, for example, parallel, repetitive choice, etc. The user can, indeed, mix different forms of fairness checking. Secondly we describe a practical approach to model checking of linear temporal formulae over the fair structures generated by SMG. Our approach is a refinement and extension of the fair-satisfiability algorithms, presented earlier by Lichtenstein and Pnueli, together with techniques developed in our practical implementations of decision procedures for linear temporal logic.

Howard Barringer; Michael D. Fisher; Graham D. Gough

1989-01-01T23:59:59.000Z

258

Analysis based on the Wavelet & Hilbert Transforms applied to the full time series of interbeats for a triad of failures at the heart  

E-Print Network (OSTI)

A tetra of sets which elements are time series including interbeats has been obtained from the databank Physionet-MIT-BIH, corresponding to the following failures at the heart of humans: Obstructive Sleep Apnea, Congestive Heart Failure, and Atrial Fibrillation, and has been analyzed statistically using an already known technique based on the Wavelet and Hilbert Transforms. That technique has been applied to the time series of interbeats for 87 patients in order to find the intrinsical dynamics of their hearts. The length of the times series varies approachly from 7 to 24 h. The kind of wavelet selected for the study has been any one belonging to the families: Daubechies, Biortoghonal, and Gaussian. The analysis has been done for the complet set of scales ranging from: 1-128 heartbeats. Choosing the Biorthogonal wavelet: bior3.1, it is observed: (a) That a time serie has not to be cutted in shorter periods with the purpose of obtaining the collapse of the data, (b) An analytical, universal behavior of the dat...

Ritto, P A

2007-01-01T23:59:59.000Z

259

Using remote-sensing data to determine equilibrium-line altitude and mass-balance time series: validation on three French glaciers,  

E-Print Network (OSTI)

Using remote-sensing data to determine equilibrium-line altitude and mass-balance time series to calculate glacier mass balance using remote-sensing data. Snowline measurements from remotely sensed images by ground measurements and remote sensing are compared and show excellent correlation (r2 > 0.89), both

Rabatel, Antoine

260

Handbook of Anatomical Models for Radiation Dosimetry (To be published in 2009 in "Series in Medical Physics and Biomedical Engineering")  

E-Print Network (OSTI)

Environmental Exposures Nina Petoussi-Henss and Kimiaki Saito Chapter 18 External Radiation Exposures in Nuclear Power Plants W. Dan Reece, Chan Hyeong Kim, and X. George Xu Chapter 19 Bioassay for Internal RadiationHandbook of Anatomical Models for Radiation Dosimetry (To be published in 2009 in "Series

Linhardt, Robert J.

Note: This page contains sample records for the topic "time series models" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Time series analysis of regional climate model performance Jason P. Evans  

E-Print Network (OSTI)

displaying particular strengths and weaknesses of its own. RegCM2 could be improved by including an ice phase in the cloud microphysics parameterization. MM5/BATS and MM5/SHEELS need revision of the formulation and verification of parameterizations involved in coupling the land surface and atmospheric components

Evans, Jason

262

Time Series Models Adoptable for Forecasting Nile Floods and Ethiopian Rainfalls  

Science Conference Proceedings (OSTI)

Long-term rainfall forecasting is used in making economic and agricultural decisions in many countries. It may also be a tool in minimizing the devastation resulting from recurrent droughts. To be able to forecast the total annual rainfall or the ...

M. G. El-Fandy; S. M. M. Taiel; Z. H. Ashour

1994-01-01T23:59:59.000Z

263

Maximum likelihood parameter estimation in time series models using sequential Monte Carlo  

E-Print Network (OSTI)

is one complete browse of y1:2000. The true parameter values: ? = 10, ? = 0.1, ?1 = 1.78, ?2 = 3.56, ?1 = 0.30, ?2 = 0.03, ?1 = ?2 = 0.1, Pi,j = 0.5. . . . . . . . . . . . . . 87 4.3 SMC-FS batch EM estimates vs number of iterations for for the same y1... EM for NMF. The (i, j)th subfigure shows the estimation result for the B(i, j) (horizontal lines). . . . . . . . . . . . . . 175 7.2 A realisation of {Xt(1)}t?1 for ? = 0.95. . . . . . . . . . . . . . . . . . . 176 7.3 Online estimation of B...

Yildirim, Sinan

2013-06-11T23:59:59.000Z

264

Aggregate Relationships between Telecommunications and Travel: Structural Equation Modeling of Time Series Data  

E-Print Network (OSTI)

Energy Review) Consumer price indices (CPIs) for private and public transportation, and airline ** Bureau of Labor Statistics (Monthly

Choo, Sangho

2003-01-01T23:59:59.000Z

265

Modeling and Simulation of a Parallel-Series Hybrid Vehicle Based on ADAMS and MATLAB  

Science Conference Proceedings (OSTI)

As the main developing direction of new energy vehicles, hybrid vehicles are highly valued by almost all automobile enterprises. For the automobile enterprises, the most important issue is accelerating the development of hybrid vehicles. The thesis creates ... Keywords: parallel-series, co-simulation, ADAMS, forward simulation

Hao Zhu; Lei Li; Cheng Qian; Yubing Xie

2012-04-01T23:59:59.000Z

266

Modelling redundancy allocation for a fuzzy random parallel-series system  

Science Conference Proceedings (OSTI)

Due to subjective judgment, imprecise human knowledge and perception in capturing statistical data, the real data of lifetimes in many systems are both random and fuzzy in nature. Based on the fuzzy random variables that are used to characterize the ... Keywords: Convergence, Fuzzy random variable, Genetic algorithm, Parallel-series system, Reliability, Sensitivity

Shuming Wang; Junzo Watada

2009-10-01T23:59:59.000Z

267

Real-time deformable models for surgery simulation: a survey  

Science Conference Proceedings (OSTI)

Simulating the behaviour of elastic objects in real time is one of the current objectives of computer graphics. One of its fields of application lies in virtual reality, mainly in surgery simulation systems. In computer graphics, the models used for ... Keywords: Animation, Deformable model, Elasticity, Real time, Surgery simulation

U. Meier; O. Lpez; C. Monserrat; M. C. Juan; M. Alcaiz

2005-03-01T23:59:59.000Z

268

Volatility Effects on the Escape Time in Financial Market Models  

E-Print Network (OSTI)

We shortly review the statistical properties of the escape times, or hitting times, for stock price returns by using different models which describe the stock market evolution. We compare the probability function (PF) of these escape times with that obtained from real market data. Afterwards we analyze in detail the effect both of noise and different initial conditions on the escape time in a market model with stochastic volatility and a cubic nonlinearity. For this model we compare the PF of the stock price returns, the PF of the volatility and the return correlation with the same statistical characteristics obtained from real market data.

Spagnolo, Bernardo

2008-01-01T23:59:59.000Z

269

Development, testing, and certification of the Northrup, Inc. , ML Series concentrating solar collector model NSC-01-0732. Final report  

DOE Green Energy (OSTI)

A summary is presented of the final results of Northrup, Inc., of Hutchins, Texas, for the additional development work on their existing ML Series concentrating solar collector Model NSC-01-0732 for use with solar heating and cooling systems. The intended use of the final report, the development hardware, deliverable end items, problems encountered during fabrication and testing, and certification statements of performance are included. It is shown that the products developed are marketable and suitable for public use.

Parker, J.C.

1979-03-01T23:59:59.000Z

270

Model checking Timed CSP Philip Armstrong Gavin Lowe Joel Ouaknine  

E-Print Network (OSTI)

Model checking Timed CSP Philip Armstrong Gavin Lowe Jo¨el Ouaknine A.W. Roscoe Oxford University Department of Computer Science Abstract Though Timed CSP was developed 25 years ago and the CSP for Timed CSP. In this paper we report on the creation of such a version, based on the digitisation results

Ouaknine, Joël

271

Periodic solution of single population models on time scales  

Science Conference Proceedings (OSTI)

By using the calculus on time scales, we study and establish criterion for the existence of periodic solutions of some scalar dynamical equations on time scales. The existence of periodic solutions for some concrete well-known single population models ... Keywords: Coincidence degree theory, Logistic equations, Periodic solutions, Time scales

Jimin Zhang; Meng Fan; Huaiping Zhu

2010-08-01T23:59:59.000Z

272

An automated translator for model checking time constrained workflow systems  

Science Conference Proceedings (OSTI)

Workflows have proven to be a useful conceptualization for the automation of business processes. While formal verification methods (e.g., model checking) can help ensure the reliability of workflow systems, the industrial uptake of such methods has been ... Keywords: automated translation, distributed model checking, modeling, time, workflow systems

Ahmed Shah Mashiyat; Fazle Rabbi; Hao Wang; Wendy MacCaull

2010-09-01T23:59:59.000Z

273

Voter Model with Time dependent Flip-rates  

E-Print Network (OSTI)

We introduce time variation in the flip-rates of the Voter Model. This type of generalisation is relevant to models of ageing in language change, allowing the representation of changes in speakers' learning rates over their lifetime and may be applied to any other similar model in which interaction rates at the microscopic level change with time. The mean time taken to reach consensus varies in a nontrivial way with the rate of change of the flip-rates, varying between bounds given by the mean consensus times for static homogeneous (the original Voter Model) and static heterogeneous flip-rates. By considering the mean time between interactions for each agent, we derive excellent estimates of the mean consensus times and exit probabilities for any time scale of flip-rate variation. The scaling of consensus times with population size on complex networks is correctly predicted, and is as would be expected for the ordinary voter model. Heterogeneity in the initial distribution of opinions has a strong effect, considerably reducing the mean time to consensus, while increasing the probability of survival of the opinion which initially occupies the most slowly changing agents. The mean times to reach consensus for different states are very different. An opinion originally held by the fastest changing agents has a smaller chance to succeed, and takes much longer to do so than an evenly distributed opinion.

G. J. Baxter

2011-04-14T23:59:59.000Z

274

The Simulation of Daily Temperature Time Series from GCM Output. Part II: Sensitivity Analysis of an Empirical Transfer Function Methodology  

Science Conference Proceedings (OSTI)

Empirical transfer functions have been proposed as a means for downscaling simulations from general circulation models (GCMs) to the local scale. However, subjective decisions made during the development of these functions may influence the ...

Julie A. Winkler; Jean P. Palutikof; Jeffrey A. Andresen; Clare M. Goodess

1997-10-01T23:59:59.000Z

275

Classification of time series generation processes using experimental tools: a survey and proposal of an automatic and systematic approach  

Science Conference Proceedings (OSTI)

By modelling the outputs produced by real world systems, we can study and, therefore, understand how they work and behave under different circumstances. This is especially interesting to support the prediction of future behaviour and, consequently, decision-making, ...

Renato P. Ishii; Ricardo A. Rios; Rodrigo F. Mello

2011-12-01T23:59:59.000Z

276

Neural Network Training for Prediction of Climatological Time Series, Regularized by Minimization of the Generalized Cross-Validation Function  

Science Conference Proceedings (OSTI)

Neural network (NN) training is the optimization process by which the relation between the NN input and output is established. A new formulation for the NN training is presented where an NN model is reconstructed such that it produces predicted ...

Yuval

2000-05-01T23:59:59.000Z

277

Transit-Time Distributions in a Global Ocean Model  

Science Conference Proceedings (OSTI)

Results from a simulation of the ocean transit-time distribution (TTD) for global and regional ocean surface boundary conditions are presented based on a 5000-yr integration using the Parallel Ocean Program ocean general circulation model. ...

Synte Peacock; Mathew Maltrud

2006-03-01T23:59:59.000Z

278

Two-Time-Step Oscillations in Numerical Weather Prediction Models  

Science Conference Proceedings (OSTI)

Spurious, nonamplifying, two-time-step oscillations are present in several numerical models of the atmosphere where the vertical diffusion is parameterized using a nonlinear diffusion equation. The problems become particularly pronounced when the ...

Ulla Hammarstrand

1997-12-01T23:59:59.000Z

279

Nonlinear Time-Reversal of Classical Waves: Experiment and Model  

E-Print Network (OSTI)

We consider time-reversal of electromagnetic waves in a closed, wave-chaotic system containing a discrete, passive, harmonic-generating nonlinearity. An experimental system is constructed as a time-reversal mirror, in which excitations generated by the nonlinearity are gathered, time-reversed, transmitted, and directed exclusively to the location of the nonlinearity. Here we show that such nonlinear objects can be purely passive (as opposed to the active nonlinearities used in previous work), and develop a high-rate secure communication system based on nonlinear time-reversal. A model of the experimental system is developed, using a star-graph network of transmission lines, with one of the lines terminated by a model diode. The model simulates time-reversal of linear and nonlinear signals, demonstrates features seen in the experimental system, and supports our interpretation of the experimental results.

Matthew Frazier; Biniyam Taddese; Bo Xiao; Thomas Antonsen; Edward Ott; Steven M. Anlage

2013-08-15T23:59:59.000Z

280

Estimating damping effectiveness of BPA`s thyristor controlled series capacitor by applying time and frequency domain methods to measured response  

Science Conference Proceedings (OSTI)

Recently, a 500-kV thyristor controlled series capacitor (TCSC) was installed in the Bonneville Power Administration system in the northwestern US. Extensive field testing has included modulation experiments to determine the effect of the TCSC on low-frequency oscillations. This paper discusses modulation procedures, analysis methods, and results for estimating the damping effectiveness of the TCSC. Modulation methods include driving the TCSC with step and random noise, and analysis techniques include time (Prony analysis) and frequency-domain identification. Results indicate that: (1) the TCSC can have significant impact on system dynamics; and (2) under a very small feedback gain, the TCSC provides measurable added damping.

Trudnowski, D.J.; Donnelly, M.K.; Hauer, J.F. [Pacific Northwest Lab., Richland, WA (United States)

1996-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "time series models" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

A timeband framework for modelling real-time systems  

Science Conference Proceedings (OSTI)

Complex real-time systems must integrate physical processes with digital control, human operation and organisational structures. New scientific foundations are required for specifying, designing and implementing these systems. One key challenge is to ... Keywords: Cyber physical, Modelling, Real-time systems

Alan Burns; Ian J. Hayes

2010-06-01T23:59:59.000Z

282

Dynamic modelling of metals - Time scales and target loads  

Science Conference Proceedings (OSTI)

Over the past decade steady-state methods have been developed to assess critical loads of metals avoiding long-term risks in view of food quality and eco-toxicological effects on organisms in soils and surface waters. However, dynamic models are needed ... Keywords: Critical loads, Delay times, Dynamic modelling, Metals, Scenario analysis, Target loads

Maximilian Posch; Wim de Vries

2009-01-01T23:59:59.000Z

283

Modeling player session times of on-line games  

Science Conference Proceedings (OSTI)

One of the most important aspects in determining the global traffic characteristics of on-line games is to model the traffic behavior of the client. While modeling the client ON-OFF times in web traffic has allowed researchers to generate accurate fractal ...

Francis Chang; Wu-chang Feng

2003-05-01T23:59:59.000Z

284

A Series of Zonal Jets Embedded in the Broad Zonal Flows in the Pacific Obtained in Eddy-Permitting Ocean General Circulation Models  

Science Conference Proceedings (OSTI)

A series of zonal currents in the Pacific Ocean is investigated using eddy-permitting ocean general circulation models. The zonal currents in the subsurface are classified into two parts: one is a series of broad zonal flows that has the ...

Hideyuki Nakano; Hiroyasu Hasumi

2005-04-01T23:59:59.000Z

285

Series Crimes  

E-Print Network (OSTI)

Puiseux series are power series in which the exponents can be fractional and/or negative rational numbers. Several computer algebra systems have one or more built-in or loadable functions for computing truncated Puiseux series. Some are generalized to allow coe?cients containing functions of the series variable that are dominated by any power of that variable, such as logarithms and nested logarithms of the series variable. Some computer algebra systems also have built-in or loadable functions that compute infinite Puiseux series. Unfortunately, there are some little-known pitfalls in computing Puiseux series. The most serious of these is expansions within branch cuts or at branch points that are incorrect for some directions in the complex plane. For example with each series implementation accessible to you: Compare the value of (z^2 + z^3)^(3/2) with that of its truncated series expansion about z = 0, approximated at z = -0.01. Does the series converge to a value that is the negative of the correct value? C...

Stoutemyer, David R

2012-01-01T23:59:59.000Z

286

Modeling and Analysis of Time-Varying Graphs  

E-Print Network (OSTI)

We live in a world increasingly dominated by networks -- communications, social, information, biological etc. A central attribute of many of these networks is that they are dynamic, that is, they exhibit structural changes over time. While the practice of dynamic networks has proliferated, we lag behind in the fundamental, mathematical understanding of network dynamism. Existing research on time-varying graphs ranges from preliminary algorithmic studies (e.g., Ferreira's work on evolving graphs) to analysis of specific properties such as flooding time in dynamic random graphs. A popular model for studying dynamic graphs is a sequence of graphs arranged by increasing snapshots of time. In this paper, we study the fundamental property of reachability in a time-varying graph over time and characterize the latency with respect to two metrics, namely store-or-advance latency and cut-through latency. Instead of expected value analysis, we concentrate on characterizing the exact probability distribution of routing l...

Basu, Prithwish; Ramanathan, Ram; Johnson, Matthew P

2010-01-01T23:59:59.000Z

287

VisIO: enabling interactive visualization of ultra-scale, time-series data via high-bandwidth distributed I/O systems  

Science Conference Proceedings (OSTI)

Petascale simulations compute at resolutions ranging into billions of cells and write terabytes of data for visualization and analysis. Interactive visuaUzation of this time series is a desired step before starting a new run. The I/O subsystem and associated network often are a significant impediment to interactive visualization of time-varying data; as they are not configured or provisioned to provide necessary I/O read rates. In this paper, we propose a new I/O library for visualization applications: VisIO. Visualization applications commonly use N-to-N reads within their parallel enabled readers which provides an incentive for a shared-nothing approach to I/O, similar to other data-intensive approaches such as Hadoop. However, unlike other data-intensive applications, visualization requires: (1) interactive performance for large data volumes, (2) compatibility with MPI and POSIX file system semantics for compatibility with existing infrastructure, and (3) use of existing file formats and their stipulated data partitioning rules. VisIO, provides a mechanism for using a non-POSIX distributed file system to provide linear scaling of 110 bandwidth. In addition, we introduce a novel scheduling algorithm that helps to co-locate visualization processes on nodes with the requested data. Testing using VisIO integrated into Para View was conducted using the Hadoop Distributed File System (HDFS) on TACC's Longhorn cluster. A representative dataset, VPIC, across 128 nodes showed a 64.4% read performance improvement compared to the provided Lustre installation. Also tested, was a dataset representing a global ocean salinity simulation that showed a 51.4% improvement in read performance over Lustre when using our VisIO system. VisIO, provides powerful high-performance I/O services to visualization applications, allowing for interactive performance with ultra-scale, time-series data.

Mitchell, Christopher J [Los Alamos National Laboratory; Ahrens, James P [Los Alamos National Laboratory; Wang, Jun [UCF

2010-10-15T23:59:59.000Z

288

Time-to-Compromise Model for Cyber Risk Reduction Estimation  

SciTech Connect

We propose a new model for estimating the time to compromise a system component that is visible to an attacker. The model provides an estimate of the expected value of the time-to-compromise as a function of known and visible vulnerabilities, and attacker skill level. The time-to-compromise random process model is a composite of three subprocesses associated with attacker actions aimed at the exploitation of vulnerabilities. In a case study, the model was used to aid in a risk reduction estimate between a baseline Supervisory Control and Data Acquisition (SCADA) system and the baseline system enhanced through a specific set of control system security remedial actions. For our case study, the total number of system vulnerabilities was reduced by 86% but the dominant attack path was through a component where the number of vulnerabilities was reduced by only 42% and the time-to-compromise of that component was increased by only 13% to 30% depending on attacker skill level.

Miles A. McQueen; Wayne F. Boyer; Mark A. Flynn; George A. Beitel

2005-09-01T23:59:59.000Z

289

Comparison of residence time models for cascading rotary dryers  

SciTech Connect

The predictions of the models of Matchett and Baker (1988), Saeman and Mitchell (1954) and Friedman and Marshall (1949) for the solids residence time in rotary dryers have been compared with both pilot-scale and industrial-scale data. A countercurrent pilot-scale dryer of 0.2m diameter and 2m long has been used with air velocities up to 1.5 m to measure the residence times of sorghum grain. The average discrepancy for the solids residence time between the predictions and the experiments that were carried out in the pilot-scale rotary dryer is {minus}10.4%. Compared with the models of Friedman and Marshall (1949) and Saeman and Mitchell (1954) for the pilot-scale data obtained here, the Matchett and Baker model is more satisfactory for predicting the solids residence time in this pilot-scale dryer. It has also been found that the model of Matchett and Baker describes the industrial data of Saeman and Mitchell (1954) than the correlation of Friedman and Marshall (1949).

Cao, W.F.; Langrish, T.A.G. [Univ. of Sydney, New South Wales (Australia). Dept. of Chemical Engineering

1999-04-01T23:59:59.000Z

290

A stochastic control model for optimal timing of climate policies  

Science Conference Proceedings (OSTI)

A stochastic control model is proposed as a paradigm for the design of optimal timing of greenhouse gas (GHG) emission abatement. The resolution of uncertainty concerning climate sensitivity and the technological breakthrough providing access to a carbon-free ... Keywords: Climate policies, Environmental hedging strategies, Piecewise deterministic Markov process, Stochastic control

O. Bahn; A. Haurie; R. Malham

2008-06-01T23:59:59.000Z

291

Statistical Characteristics of a Real-Time Precipitation Forecasting Model  

Science Conference Proceedings (OSTI)

At Colorado State University the Regional Atmospheric Modeling System (RAMS) has been used to produce real-time forecasts of precipitation for the Colorado mountain region since 1991. Originally a so-called dump-bucket scheme was used to generate ...

Brian Gaudet; William R. Cotton

1998-12-01T23:59:59.000Z

292

Enhanced modeling : real-time simulation and modeling of graph based problems on interactive workbenches  

E-Print Network (OSTI)

This thesis presents a methodology and framework for designing systems that apply real-time simulation of computational models throughout the modeling and parameter modification stages of problem solving for graph based ...

Chak, Daniel, 1980-

2004-01-01T23:59:59.000Z

293

The design and quality assurance of the VACOSS series production model  

SciTech Connect

The production model of the electronic safeguards seal system VACOSS was developed and it quality assurance programme carried out under the Federal Republic of Germany programme in support of the International Atomic Energy Agency. The opening and closing of an optical fibre cable are controlled by a battery powered microprocessor. The electronic circuitry of the seal is surface mounted on two boards. A standard Li block battery has been chosen for reason of a service life of more than one year. Alternatively, a worldwide available standard 9 V block battery can be used, however, at the expense of a reduced service life. The coated electronic circuitry and the battery are contained in an injection-moulded casing. The interrogation and initialization unit has a 4 x 16 column alphanumeric liquid crystal display for user-friendly, menu-guided operation. A hardcopy of the display can be produced by connecting a printer. The seal has been qualified using military specification standards. An acceptance test programme was carried out using 8 seals. In addition, the seal electronics was subjected to in-circuit and burn-in testing.

Richter, B.; Stein, G. (Kernforschungsanlage Juelich GmbH, D-5170 Juelich (DE)); Guenzel, R. (Dornier-System GmbH, D-7990 Friedrichshafen 1 (DE)); Gaertner, K.J.; Yellin, E. (International Atomic Energy Agency, Vienna (AT))

1988-01-01T23:59:59.000Z

294

Efficient Decompositional Model-Checking for Regular Timing Diagrams  

E-Print Network (OSTI)

There is a growing need to make verification tools easier to use. A solution that does not require redesigning the tool is to construct front-ends providing specification notations that are close to those used in practice. Timing diagrams are such a widely used graphical notation, one that is often more appealing than a "linear" textual notation. This paper introduces a class of timing diagrams called Regular Timing Diagrams (RTDs). RTDs have a precise syntax and a formal semantics that is simple and corresponds to common usage. In addition, RTDs have an inherent compositional structure, which is exploited to provide an efficient algorithm for model-checking an RTD with respect to a system description. The algorithm has time complexity that is a small polynomial in the size of the diagram and linear in the size of the structure. We demonstrate the applicability of our algorithms by verifying that a master-slave system satisfies its specification RTDs.

Nina Amla; E. Allen Emerson; Kedar S. Namjoshi

1999-01-01T23:59:59.000Z

295

Poincar series  

Science Conference Proceedings (OSTI)

It is known that the series ~(v, k; G) are parabolic forms with respect to the subgroup. G and generate the whole space of parabolic forms Sk(G). Petersson...

296

Improved time-domain accuracy standards for model gravitational waveforms  

Science Conference Proceedings (OSTI)

Model gravitational waveforms must be accurate enough to be useful for detection of signals and measurement of their parameters, so appropriate accuracy standards are needed. Yet these standards should not be unnecessarily restrictive, making them impractical for the numerical and analytical modelers to meet. The work of Lindblom, Owen, and Brown [Phys. Rev. D 78, 124020 (2008)] is extended by deriving new waveform accuracy standards which are significantly less restrictive while still ensuring the quality needed for gravitational-wave data analysis. These new standards are formulated as bounds on certain norms of the time-domain waveform errors, which makes it possible to enforce them in situations where frequency-domain errors may be difficult or impossible to estimate reliably. These standards are less restrictive by about a factor of 20 than the previously published time-domain standards for detection, and up to a factor of 60 for measurement. These new standards should therefore be much easier to use effectively.

Lindblom, Lee [Theoretical Astrophysics 350-17, California Institute of Technology, Pasadena, California 91125 (United States); Baker, John G. [Gravitational Astrophysics Laboratory, NASA/GSFC, Greenbelt, Maryland 20771 (United States); Owen, Benjamin J. [Institute for Gravitation and the Cosmos, Center for Gravitational Wave Physics, Department of Physics, Pennsylvania State University, University Park, Pennsylvania 16802 (United States)

2010-10-15T23:59:59.000Z

297

Electric Load vs Time: Complicated World, Complicated Model  

NLE Websites -- All DOE Office Websites (Extended Search)

Electric Load vs Time: Complicated World, Complicated Model Electric Load vs Time: Complicated World, Complicated Model Speaker(s): Phillip Price Date: March 7, 2013 - 12:00pm Location: 90-3122 Seminar Host/Point of Contact: Phillip Price "How much energy did I save by changing the operation of my building yesterday?" That turns out to be a very hard question to answer: you need to know how much energy you would have used under normal operations (the "baseline"), a number you can predict but not measure. In this talk we focus specifically on electrical energy ("electric load") in commercial buildings. Often the load can be broken down into several components that are superimposed on each other: a recurring weekly pattern, an effect of outdoor air temperature, and so on. Some buildings have patterns that are

298

Modeling Time-dependent Responses of Piezoelectric Fiber Composite  

E-Print Network (OSTI)

The existence of polymer constituent in piezoelectric fiber composites (PFCs) could lead to significant viscoelastic behaviors, affecting overall performance of PFCs. High mechanical and electrical stimuli often generate significant amount of heat, increasing temperatures of the PFCs. At elevated temperatures, most materials, especially polymers show pronounced time-dependent behaviors. Predicting time-dependent responses of the PFCs becomes important to improve reliability in using PFCs. We study overall performance of PFCs having unidirectional piezoceramic fibers, such as PZT fibers, dispersed in viscoelastic polymer matrix. Two types of PFCs are studied, which are active fiber composites (AFCs) and macro fiber composites (MFCs). AFCs and MFCs consist of unidirectional PZT fibers dispersed in epoxy placed between two interdigitated electrode and kapton layers. The AFCs have a circular fiber cross-section while the MFCs have a square fiber cross-section. Finite element (FE) models of representative volume elements (RVEs) of active PFCs, having square and circular fiber cross-sections, are generated for composites with 20, 40, and 60 percent fiber contents. Two FE micromechanical models having one fiber embedded in epoxy matrix and five fibers placed in epoxy matrix are considered. A continuum 3D piezoelectric element in ABAQUS FE is used. A general time-integral function is applied for the mechanical, electrical, and piezoelectric properties in order to incorporate the time-dependent effect and histories of loadings. The effective properties of PZT-5A/epoxy and PZT-7A/LaRC-SI piezocomposites determined from the FE micromechanical models are compared to available experimental data and analytical solutions in the literature. Furthermore, the effect of viscoelastic behaviors of the LaRC-SI matrix at an elevated temperature on the overall electro-mechanical and piezoelectric constants are examined.

Li, Kuo-An

2009-12-01T23:59:59.000Z

299

Analysis of real-time reservoir monitoring : reservoirs, strategies, & modeling.  

Science Conference Proceedings (OSTI)

The project objective was to detail better ways to assess and exploit intelligent oil and gas field information through improved modeling, sensor technology, and process control to increase ultimate recovery of domestic hydrocarbons. To meet this objective we investigated the use of permanent downhole sensors systems (Smart Wells) whose data is fed real-time into computational reservoir models that are integrated with optimized production control systems. The project utilized a three-pronged approach (1) a value of information analysis to address the economic advantages, (2) reservoir simulation modeling and control optimization to prove the capability, and (3) evaluation of new generation sensor packaging to survive the borehole environment for long periods of time. The Value of Information (VOI) decision tree method was developed and used to assess the economic advantage of using the proposed technology; the VOI demonstrated the increased subsurface resolution through additional sensor data. Our findings show that the VOI studies are a practical means of ascertaining the value associated with a technology, in this case application of sensors to production. The procedure acknowledges the uncertainty in predictions but nevertheless assigns monetary value to the predictions. The best aspect of the procedure is that it builds consensus within interdisciplinary teams The reservoir simulation and modeling aspect of the project was developed to show the capability of exploiting sensor information both for reservoir characterization and to optimize control of the production system. Our findings indicate history matching is improved as more information is added to the objective function, clearly indicating that sensor information can help in reducing the uncertainty associated with reservoir characterization. Additional findings and approaches used are described in detail within the report. The next generation sensors aspect of the project evaluated sensors and packaging survivability issues. Our findings indicate that packaging represents the most significant technical challenge associated with application of sensors in the downhole environment for long periods (5+ years) of time. These issues are described in detail within the report. The impact of successful reservoir monitoring programs and coincident improved reservoir management is measured by the production of additional oil and gas volumes from existing reservoirs, revitalization of nearly depleted reservoirs, possible re-establishment of already abandoned reservoirs, and improved economics for all cases. Smart Well monitoring provides the means to understand how a reservoir process is developing and to provide active reservoir management. At the same time it also provides data for developing high-fidelity simulation models. This work has been a joint effort with Sandia National Laboratories and UT-Austin's Bureau of Economic Geology, Department of Petroleum and Geosystems Engineering, and the Institute of Computational and Engineering Mathematics.

Mani, Seethambal S.; van Bloemen Waanders, Bart Gustaaf; Cooper, Scott Patrick; Jakaboski, Blake Elaine; Normann, Randy Allen; Jennings, Jim (University of Texas at Austin, Austin, TX); Gilbert, Bob (University of Texas at Austin, Austin, TX); Lake, Larry W. (University of Texas at Austin, Austin, TX); Weiss, Chester Joseph; Lorenz, John Clay; Elbring, Gregory Jay; Wheeler, Mary Fanett (University of Texas at Austin, Austin, TX); Thomas, Sunil G. (University of Texas at Austin, Austin, TX); Rightley, Michael J.; Rodriguez, Adolfo (University of Texas at Austin, Austin, TX); Klie, Hector (University of Texas at Austin, Austin, TX); Banchs, Rafael (University of Texas at Austin, Austin, TX); Nunez, Emilio J. (University of Texas at Austin, Austin, TX); Jablonowski, Chris (University of Texas at Austin, Austin, TX)

2006-11-01T23:59:59.000Z

300

Continuous Time Series of Catchment-Averaged Sensible Heat Flux from a Large Aperture Scintillometer: Efficient Estimation of Stability Conditions and Importance of Fluxes under Stable Conditions  

Science Conference Proceedings (OSTI)

A large aperture scintillometer (LAS) observes the intensity of the atmospheric turbulence across large distances, which is related to the path-averaged sensible heat flux H. In this paper, two problems in the derivation of continuous series of H ...

Bruno Samain; Willem Defloor; Valentijn R. N. Pauwels

2012-04-01T23:59:59.000Z

Note: This page contains sample records for the topic "time series models" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Average waiting time profiles of uniform DQDB model  

SciTech Connect

The Distributed Queue Dual Bus (DQDB) system consists of a linear arrangement of N nodes that communicate with each other using two contra-flowing buses; the nodes use an extremely simple protocol to send messages on these buses. This simple, but elegant, system has been found to be very challenging to analyze. We consider a simple and uniform abstraction of this model to highlight the fairness issues in terms of average waiting time. We introduce a new approximation method to analyze the performance of DQDB system in terms of the average waiting time of a node expressed as a function of its position. Our approach abstracts the intimate relationship between the load of the system and its fairness characteristics, and explains all basic behavior profiles of DQDB observed in previous simulation. For the uniform DQDB with equal distance between adjacent nodes, we show that the system operates under three basic behavior profiles and a finite number of their combinations that depend on the load of the network. Consequently, the system is not fair at any load in terms of the average waiting times. In the vicinity of a critical load of 1 {minus} 4/N, the uniform network runs into a state akin to chaos, where its behavior fluctuates from one extreme to the other with a load variation of 2/N. Our analysis is supported by simulation results. We also show that the main theme of the analysis carries over to the general (non-uniform) DQDB; by suitably choosing the inter-node distances, the DQDB can be made fair around some loads, but such system will become unfair as the load changes.

Rao, N.S.V. [Oak Ridge National Lab., TN (United States); Maly, K.; Olariu, S.; Dharanikota, S.; Zhang, L.; Game, D. [Old Dominion Univ., Norfolk, VA (United States). Dept. of Computer Science

1993-09-07T23:59:59.000Z

302

Series A.  

Office of Legacy Management (LM)

.WGJPH-146 ' .WGJPH-146 ' 3 .P' , p3 ."J$i v-e- \. Cont&ning 3 pages Consisting of 0 figuree. Copy No. &of-G copies Series A. , / October 19, 1943 I:. ;I, ' , r;l ?" I ' I' 0 : J. Chipman r'rcro: John P. Howe In Re: Trip to ClYveland, Ohio, October 11, I.943 Thie is to report on the conference held on October 11th in which the pro+. 'g'.*rSs of the coating pork at the Cirasselli Labara*torios ores reviewed. lh05e pToSs;lt were: A. S. I?;ey,uendt; J, C. !'ioodhouse; M. T. Goebel; L. R. kstbrook; .4. Ii. Gray; J. P. Howe; Z. Ft. Keller. YI.,XTFXIP~UTIN~ - A, G. Grcv --- Gray summar ized the progress j;n ,elactropkti:~y, much as is givan ic Yr:e : &.$. .:r : -3 reports of the !l'whnicriL Division. ,. .I c.. , lhe.main points were: ~~'orit i< f:c~!--

303

A Macroscopic Behavior Model for Self-Timed Pipeline Systems  

Science Conference Proceedings (OSTI)

This paper presents a novel macroscopic behavior modelfor self-timed pipeline (STP). STP is a promising architecturefor system-on-chip (SoC) design, because STP easesthe timing problems and abnegates the control dependenciesamong building components ...

Shuji Sannomiya; Yoichi Omori; Makoto Iwata

2003-06-01T23:59:59.000Z

304

Modeling Metal Fatigue As a Key Step in PV Module Life Time Prediction (Presentation)  

DOE Green Energy (OSTI)

This presentation covers modeling metal fatigue as a key step in photovoltaic (PV) module lifetime predictions. Described are time-dependent and time-independent case studies.

Bosco, N.

2012-02-01T23:59:59.000Z

305

Time-series analysis for the episodic production and transport of methane from the Glacial Lake Agassiz peatlands, northern Minnesota. Final report  

SciTech Connect

The large peat basins of North America are an important reservoir in the global carbon cycle and a significant source of atmospheric methane. The authors investigated carbon cycling in the Glacial Lake Agassiz peatlands (GLAP) of Minnesota. Initially in 1990, they identified a dramatic change in the concentration of methane in the pore-waters of the raised bogs in the GLAP during an extreme drought. This methane dissipated when the drought broke in 1991 and the occurrence of deep methane is related to changes in the direction of groundwater flow in the peat column. The production of methane and its diffusive loss to the atmosphere was modeled and was about 10 times less than that measured directly in chambers at the land surface. It is clear from the reversals in hydraulic heat, changes in pore-water chemical composition over time, and paleostratigraphic markers, that regional ground water flow systems that are controlled by climate change are unexpectedly a major control over methanogenesis and carbon cycling in GLAP. Seismic profiles made showed that buried bedrock ridges particularly deflect regional groundwater flow upwards towards the land surface and towards raised bog landforms. In addition, high-resolution GPS measurements from data stations funded by this DOE project have shown this year that the peakland land surface elevation changes daily on a scale of cms, and seasonally on a scale of 10s of cm. This most recent observation is exciting because it may reflect episodic degassing of free phase methane from the peat column to the atmosphere, a source for methane previously unaccounted for by methane researchers.

Siegel, D.I.

1998-01-01T23:59:59.000Z

306

Distinguished Lecturers Series  

NLE Websites -- All DOE Office Websites (Extended Search)

Videos Videos Lawrence Berkeley National Laboratory Environmental Energy Technologies Division Distinguished Lecture Series Environmental Energy Technologies Division Distinguished Lecture Series Videos Long Fuse, Big Bang: Thomas Edison, Electricity, and the Locus of Innovation Andrew Hargadon, October 22, 2012 Climate Change Hits Home: Impacts on the Built Environment and Health John Spengler, June 18, 2012 High Comfort-Low Impact, From Buildings to Cities Matthias Schuler, April 30, 2012 Emissions Trading and Climate Finance: Is 2012 the Dead End or the Crossroads? Marc Stuart, January 27, 2012 Advances in Global Climate Modeling for Scientific Understanding and Predictability V. Ramaswamy, October 7, 2011 How is Building Energy Use Related to Occupant Behaviors and Building Usage

307

Multi-Time Scaling Crystal Plasticity FE Models Dwell Fatigue ...  

Science Conference Proceedings (OSTI)

First Principles Modeling of Shape Memory Alloy Magnetic Refrigeration Materials ... of Lithium Battery Materials LiMPO4 (M = Mn, Fe, Co, and Ni): A Comparative ... Forming-Crush Simulation Optimization Using Internal State Variable Model.

308

Elastoplastic Phase Field Model for Time-Dependent Hydrogen ...  

Science Conference Proceedings (OSTI)

First Principles Modeling of Shape Memory Alloy Magnetic Refrigeration Materials ... of Gamma Prime Precipitates in a Commercial Nickel Base Superalloy.

309

Search Method for Real-time Knowledge Discovery Modeled on ...  

nodes in a system of multiple computers according to rules for complex, hierarchical system modeled on the human brain.

310

The Simulation of Daily Temperature Time Series from GCM Output. Part I: Comparison of Model Data with Observations  

Science Conference Proceedings (OSTI)

For climate change impact analyses, local scenarios of surface variables at the daily scales are frequently required. Empirical transfer functions are a widely used technique to generate scenarios from GCM data at these scales. For successful ...

J. P. Palutikof; J. A. Winkler; C. M. Goodess; J. A. Andresen

1997-10-01T23:59:59.000Z

311

Effects of Historical Urbanization in the Brussels Capital Region on Surface Air Temperature Time Series: A Model Study  

Science Conference Proceedings (OSTI)

The authors examine the local impact of change in impervious surfaces in the Brussels capital region (BCR), Belgium, on trends in maximum, minimum, and mean temperatures between 1960 and 1999. Specifically, data are combined from remote sensing ...

R. Hamdi; A. Deckmyn; P. Termonia; G. R. Demare; P. Baguis; S. Vanhuysse; E. Wolff

2009-10-01T23:59:59.000Z

312

Time consistency and risk averse dynamic decision models ...  

E-Print Network (OSTI)

asset and liability management, scheduling and energy planning. Indeed, ..... the recursive time consistent alternative developed for a CVaR-based portfo-.

313

Nonmonotonic Relaxation as a Result of Spatial Heterogeneity in the Model of In-series Blocks Chain  

E-Print Network (OSTI)

Recently the materials possessing structure of molecular and supramolecular matrix are more and more actively studied. They are relative to many polymeric materials of a technological origin, such as rubber, and living biological tissues. Processes of mechanical deformation of these continuous media have peculiarities connected, first, with accounting for internal friction and dissipation of energy, and secondly, with nonlinearity of their elastic and viscous properties, that is with violation of Hook and Newtons laws. Traditional approaches to mechanics of viscoelastic bodies sometimes are excessively difficult, and more evident and available representations are necessary. The invaluable role in studying of the operating processes mechanisms of elastic deformation and motility of biological materials is played by the mathematical modeling. New effect obtained by means of computer experiment of nonmonotonic relaxation of deformation in heterogeneous media is considered in the present work. Rheological properties of described media are governed by the differential equations of the first order on time (the evolution equations), as well as a huge variety of other physical processes. The physical phenomena in nonlinear systems with dissipation have a big community, including such it would seem far areas, as dynamics of magnetization in ferrite. Therefore the problem of studying new effects of viscous friction in the conditions of nonlinearity and heterogeneity, is very actual as in respect of fundamental research nonlinear and non-uniform environments, and in many areas of materials science, design of new materials, engineering of biological substitutes of living tissues and development of the micromagnetic devices using essentially new opportunities.

A. A. Bedulina; A. V. Kobelev

2013-06-25T23:59:59.000Z

314

Non-markovian analysis for model driven engineering of real-time software  

Science Conference Proceedings (OSTI)

Quantitative evaluation of models with stochastic timings can decisively support schedulability analysis and performance engineering of real-time concurrent systems. These tasks require modeling formalisms and solution techniques that can encompass stochastic ... Keywords: model driven development, non-markovian stochastic analysis, real-time systems, software performance engineering

Laura Carnevali; Marco Paolieri; Alessandro Santoni; Enrico Vicario

2013-04-01T23:59:59.000Z

315

Decreasing Computational Time of Urban Cellular Automata Through Model Portability  

Science Conference Proceedings (OSTI)

This paper investigates how portability of a model between different computer operating systems can lead to increased efficiency in code execution. The portability problem is not a trivial one, as many geographic models are designed to be run inside ... Keywords: Calibration, Cellular automata, Portability

Charles Dietzel; Keith C. Clarke

2006-06-01T23:59:59.000Z

316

Parallel Graph Transformation for Model Simulation applied to Timed Transition Petri Nets  

Science Conference Proceedings (OSTI)

This work discusses the use of parallel graph transformation systems for (multi-formalism) modeling and simulation and their implementation in the meta-modeling tool AToM^3. As an example, a simulator for Timed Transition Petri Nets (TTPN) is modeled ... Keywords: model simulation, parallel graph transformation, timed transition Petri nets

J. de Lara; C. Ermel; G. Taentzer; K. Ehrig

2004-12-01T23:59:59.000Z

317

Real Time Models of the Asynchronous Circuits: The Delay Theory  

E-Print Network (OSTI)

The chapter from the book introduces the delay theory, whose purpose is the modeling of the asynchronous circuits from digital electrical engineering with ordinary and differential pseudo-boolean equations.

Serban E. Vlad

2004-12-17T23:59:59.000Z

318

Configurable model for real-time crane erection visualization  

Science Conference Proceedings (OSTI)

Detailed simulation and visualization of crane activities have been recently introduced to help engineers identify potential problems with critical erection tasks; however, the development of real-time erection visualizations for different types of cranes ... Keywords: Cooperative, Crane, Erection, Multibody, Physics Engine, Simulation, Visualization

Wei-Han Hung, Shih-Chung Kang

2013-11-01T23:59:59.000Z

319

Analysis of Acoustic Signatures from Moving Vehicles UsingTime-Varying Autoregressive Models  

Science Conference Proceedings (OSTI)

Time-varying autoregressive (TVAR) modeling approach for the analysis of acoustic signatures from moving vehicles is presented in this paper. Acoustic signatures from moving vehicles are nonstationary, and features extracted under the stationary ... Keywords: acoustic, classification, time-varying autoregressive model, time-varying, vehicle identification

Kie B. Eom

1999-10-01T23:59:59.000Z

320

Patterns for Automatic Generation of Soft Real-time System Models  

Science Conference Proceedings (OSTI)

Worst-case assumptions about the timing of systems are often too conservative when analyzing distributed soft real-time systems as they lead to over-dimensioned and expensive products. For these systems, a certain percentage of deadline misses is often ... Keywords: Modeling patterns, pattern-based system description, soft real-time systems, stochastic model

Oana Florescu; Jeroen Voeten; Bart Theelen; Henk Corporaal

2009-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "time series models" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

A Global Time-Dependent Model of Thunderstorm Electricity. Part I: Mathematical Properties of the Physical and Numerical Models  

Science Conference Proceedings (OSTI)

A time-dependent model that simulates the interaction of a thunderstorm with its electrical environment is introduced. The model solves the continuity equation of the Maxwell current density that includes conduction, displacement, and source ...

G. L. Browning; I. Tzur; R. G. Roble

1987-08-01T23:59:59.000Z

322

Energy-Efficient, Utility Accrual Real-Time Scheduling Under the Unimodal Arbitrary Arrival Model  

Science Conference Proceedings (OSTI)

We present an energy-efficient real-time scheduling algorithm called EUA*, for the unimodal arbitrary arrival model (or UAM). UAM embodies a "stronger" adversary than most arrival models. The algorithm considers application activities that are subject ...

Haisang Wu; Binoy Ravindran; E. Douglas Jensen

2005-03-01T23:59:59.000Z

323

A Three-Dimensional Time-Dependent Global Model of the Thermosphere  

Science Conference Proceedings (OSTI)

A global, three-dimensional, time-dependent numerical model of the thermosphere has been created to simulate the dynamical behavior of the earth's thermosphere under a wide variety of geophysical conditions. Comparison of the model's predictions ...

T. J. Fuller-Rowell; D. Rees

1980-11-01T23:59:59.000Z

324

One-Dimensional Time-Dependent Modeling of GATE Cumulonimbus Convection  

Science Conference Proceedings (OSTI)

A one-dimensional time-dependent cumulonimbus model is designed that, unlike in previous one-dimensional models, simulates cloud-top heights, vertical velocities, and water contents that are reasonably consistent with those observed in real ...

Brad Schoenberg Ferrier; Robert A. Houze Jr.

1989-02-01T23:59:59.000Z

325

Time-Dependent Adjustment in a Simple Model of the Mid-Depth Meridional Overturning Cell  

Science Conference Proceedings (OSTI)

A recently proposed reduced-gravity model of the warm-water branch of the middepth meridional overturning circulation in a rectangular basin with a circumpolar connection is extended to include time dependence. The model describes the balance ...

R. M. Samelson

2011-05-01T23:59:59.000Z

326

A Forward-in-Time Anelastic Nonhydrostatic Model in a Terrain-Following Coordinate  

Science Conference Proceedings (OSTI)

A three-dimensional (3D) forward-in-time anelastic nonhydrostatic model in a terrain-following coordinate is developed to investigate mesoscale circulations over topography. The anelastic nonhydrostatic model utilizes the deep-continuity equation,...

Ching-Yuang Huang

2000-07-01T23:59:59.000Z

327

A Real-Time Hurricane Surface Wind Forecasting Model: Formulation and Verification  

Science Conference Proceedings (OSTI)

A real-time hurricane wind forecast model is developed by 1) incorporating an asymmetric effect into the Holland hurricane wind model; 2) using the National Oceanic and Atmospheric Administration (NOAA)/National Hurricane Centers (NHC) hurricane ...

Lian Xie; Shaowu Bao; Leonard J. Pietrafesa; Kristen Foley; Montserrat Fuentes

2006-05-01T23:59:59.000Z

328

Model-based estimation of time-varying parameters and state variables in aerobic bioprocesses  

Science Conference Proceedings (OSTI)

Keywords: adaptive observer, aerobic bioprocess, biomass concentration, biomass growth rate, model-based estimation, observer stability, oxygen comsumption, time-varying parameters, yield coefficient

V. Lubenova

2000-08-01T23:59:59.000Z

329

Search Method for Real-time Knowledge Discovery Modeled on the ...  

Search Method for Real-time Knowledge Discovery Modeled on the Human Brain Oak Ridge National Laboratory. Contact ORNL About This Technology

330

Developing a time-domain finite-element method for modeling of electromagnetic cylindrical cloaks  

Science Conference Proceedings (OSTI)

In this paper we propose a time-domain finite element method for modeling of electromagnetic cloaks. The permittivity and permeability of the cloak model are described by the Drude dispersion model. The model to be solved is quite challenging in that ... Keywords: Finite element method, Invisibility cloak, Maxwell's equations

Jichun Li; Yunqing Huang; Wei Yang

2012-04-01T23:59:59.000Z

331

Evaluation of scalar mixing and time scale models in PDF simulations of a turbulent premixed flame  

SciTech Connect

Numerical simulation results obtained with a transported scalar probability density function (PDF) method are presented for a piloted turbulent premixed flame. The accuracy of the PDF method depends on the scalar mixing model and the scalar time scale model. Three widely used scalar mixing models are evaluated: the interaction by exchange with the mean (IEM) model, the modified Curl's coalescence/dispersion (CD) model and the Euclidean minimum spanning tree (EMST) model. The three scalar mixing models are combined with a simple model for the scalar time scale which assumes a constant C{sub {phi}}=12 value. A comparison of the simulation results with available measurements shows that only the EMST model calculates accurately the mean and variance of the reaction progress variable. An evaluation of the structure of the PDF's of the reaction progress variable predicted by the three scalar mixing models confirms this conclusion: the IEM and CD models predict an unrealistic shape of the PDF. Simulations using various C{sub {phi}} values ranging from 2 to 50 combined with the three scalar mixing models have been performed. The observed deficiencies of the IEM and CD models persisted for all C{sub {phi}} values considered. The value C{sub {phi}}=12 combined with the EMST model was found to be an optimal choice. To avoid the ad hoc choice for C{sub {phi}}, more sophisticated models for the scalar time scale have been used in simulations using the EMST model. A new model for the scalar time scale which is based on a linear blending between a model for flamelet combustion and a model for distributed combustion is developed. The new model has proven to be very promising as a scalar time scale model which can be applied from flamelet to distributed combustion. (author)

Stoellinger, Michael; Heinz, Stefan [Department of Mathematics, University of Wyoming, Laramie, WY (United States)

2010-09-15T23:59:59.000Z

332

Distinguished Lecture Series  

NLE Websites -- All DOE Office Websites (Extended Search)

Distinguished Lecture Series Distinguished Lecture Series Long Fuse, Big Bang: Thomas Edison, Electricity, and the Locus of Innovation Andrew Hargadon October 22, 2012 - 12:00pm...

333

Time Series of Aerosol Column Optical Depth at the Barrow, Alaska, ARM Climate Research Facility for 2008 Fourth Quarter 2009 ARM and Climate Change Prediction Program Metric Report  

Science Conference Proceedings (OSTI)

The uncertainties in current estimates of anthropogenic radiative forcing are dominated by the effects of aerosols, both in relation to the direct absorption and scattering of radiation by aerosols and also with respect to aerosol-related changes in cloud formation, longevity, and microphysics (See Figure 1; Intergovernmental Panel on Climate Change, Assessment Report 4, 2008). Moreover, the Arctic region in particular is especially sensitive to changes in climate with the magnitude of temperature changes (both observed and predicted) being several times larger than global averages (Kaufman et al. 2009). Recent studies confirm that aerosol-cloud interactions in the arctic generate climatologically significant radiative effects equivalent in magnitude to that of green house gases (Lubin and Vogelmann 2006, 2007). The aerosol optical depth is the most immediate representation of the aerosol direct effect and is also important for consideration of aerosol-cloud interactions, and thus this quantity is essential for studies of aerosol radiative forcing.

C Flynn; AS Koontz; JH Mather

2009-09-01T23:59:59.000Z

334

MODEST: A Compositional Modeling Formalism for Hard and Softly Timed Systems  

Science Conference Proceedings (OSTI)

This paper presents Modest (MOdeling and DEscription language for Stochastic Timed systems), a formalism that is intended to support 1) the modular description of reactive systems' behavior while covering both 2) functional and 3) nonfunctional system ... Keywords: Modeling formalism, compositionality, formal semantics, timed automata, stochastic processes.

Henrik Bohnenkamp; Pedro R. D'Argenio; Holger Hermanns; Joost-Pieter Katoen

2006-10-01T23:59:59.000Z

335

A "Nearly Ideal" Solution to Linear Time-Varying Rational Expectations Models  

Science Conference Proceedings (OSTI)

For a well-identified class of forward-looking models under rational expectations and time-varying parameters, it is shown that there exists always a solution having the property of being the closest, in mean square, to the state motion of the autoregressive ... Keywords: C5, C6, Kalman Filtering, Rational expectations models, Time-varying parameters

Francesco Carravetta; Marco M. Sorge

2010-04-01T23:59:59.000Z

336

Measurement, Analysis and Modeling of real-time Source Data traffic in Factory Communication Systems  

E-Print Network (OSTI)

In the performance evaluation and design of communication systems for distributed automation systems the almost realistic modeling of the data traffic of automation devices plays a decisive part. Therefore the real-time communication behaviour of a high-grade automated installation in the discrete manufacturing is evaluated. Selected communication requirements are analysed and transferred to a analytic model. This model finally is validated.

Juergen Jasperneite; Peter Neumann

2000-01-01T23:59:59.000Z

337

Discrete-Time Multi-Resolution Modeling of Switching Power Converters Using Wavelets  

Science Conference Proceedings (OSTI)

Modeling of power electronics circuits presents significant challenges due to the non-linear time-varying behaviour of this kind of system. It is common practice to operate with families of models of different complexity depending on the analysis goal. ... Keywords: modeling, power conversion, power electronics, wavelet transforms

Ferdinanda Ponci; Enrico Santi; Antonello Monti

2009-02-01T23:59:59.000Z

338

Ris DTU 09-06-08 Waste-to-energy technologies in TIMES models  

E-Print Network (OSTI)

-to-energy technologies in the Pan-European NEEDS- TIMES model Waste incineration for electricity and heat, landfill gas legislation on waste Directives · Waste Framework Directive, 1975 (75/442/EEC) · Directive on the landfill be accepted as recovery) Avoid · Landfill #12;Risø DTU 09-06-08 4 European waste model Econometric model

339

An n-gram topic model for time-stamped documents  

Science Conference Proceedings (OSTI)

This paper presents a topic model that captures the temporal dynamics in the text data along with topical phrases. Previous approaches have relied upon bag-of-words assumption to model such property in a corpus. This has resulted in an inferior performance ... Keywords: bayesian inference, collapsed gibbs sampling, n-gram words, temporal data, topic model, topics over time

Shoaib Jameel; Wai Lam

2013-03-01T23:59:59.000Z

340

Incident detection using the Standard Normal Deviate model and travel time information from probe vehicles  

E-Print Network (OSTI)

One application of travel time information explored in this thesis is freeway incident detection. It is vital to develop reliable methods for automatically detecting incidents to facilitate the quick response and removal of incidents before they cause breakdowns in traffic flow. The use of real-time travel time data to monitor freeway conditions has the advantages over conventional loop detectors of taking into account the dynamic, longitudinal nature of traffic flow and requiring data from only a portion of the traffic stream. This study employed the Standard Normal Deviate (SND) Model to test the feasibility of using travel time data to detect lane blocking incidents. The fundamental concept of the SND Model was based on the comparison of real-time travel time data to historical travel time data for given freeway segments during specified times. The travel time and incident reports used were collected through the Real-Time Traffic Information System (RTTIS) in the north freeway corridor of Houston, Texas using probe vehicles equipped with cellular telephones. The data were compiled on 39 freeway links from October 1991 through August 1992 on weekdays during morning and afternoon data collection periods. The results of incident detection tests, applying the SND Model to incident and travel time me data from the North Freeway, indicated high successful incident detection rates. However, high false alarm rates also resulted from the SND Model test applications. An optimum SND value of 2.0 was observed for the North Freeway test data. At this value the SND tests produced successful incident detection rates of 70 percent and higher during both the morning and afternoon periods. False alarm rates were also 70 percent. The best results were achieved on those freeway sections where the most incident and travel time data had been collected. The overall results of the incident detection tests on the North Freeway demonstrated that the SND Model was a feasible incident detection algorithm, but required an extensive historical travel time data base.

Mountain, Christopher Eugene

1993-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "time series models" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Testing for Drift in a Time Series  

E-Print Network (OSTI)

;c6#28; #16;t @ #22;i#16;}#4;|#16;?} u#3;?U|#16;L?c t#3;U#4; @t |#4;i #18;@h|*i|| #22;#16;?_L#22;c #25;E#12;c6#28; #3; m#12; m*E6n #28;c @?_ e #14;E#12;#28; #16;t |#4;i t@4T*i @#3;|LUL#15;@h#16;@?Ui Lu |#4;i hit#16;_#3;@*tc {+ | #3; e qc...

Busetti, Fabio; Harvey, Andrew C

2004-06-16T23:59:59.000Z

342

A Time Series of Agulhas Undercurrent Transport  

Science Conference Proceedings (OSTI)

A 550-day record of Agulhas Undercurrent transport between March 2003 and August 2004 is constructed from five deep moorings placed on the continental shelf off South Africa at nominally 32S. The vertical and lateral scales of the undercurrent ...

Lisa M. Beal

2009-10-01T23:59:59.000Z

343

An Explicit One-Dimensional Time-Dependent Tilting Cloud Model  

Science Conference Proceedings (OSTI)

An explicit one-dimensional time-dependent tilting cloud model has been developed for use in cumulus parameterizations. The tilting axis is not necessarily orthogonal to the (r, ?) plane, making the horizontal axisymmetric assumption more ...

Shu-Hua Chen; Wen-Yih Sun

2004-12-01T23:59:59.000Z

344

An Eddy-Resolving Numerical Model of the Ventilated Thermocline: Time Dependence  

Science Conference Proceedings (OSTI)

A primitive equation, eddy-resolving numerical model is used to study the inherent time scales of variability in the subtropical ocean, assuming temporally constant surface forcing. Three primary scales arise: mesoscale variability of roughly 50-...

Michael D. Cox

1987-07-01T23:59:59.000Z

345

Gaussian Model Adaptive Processing in Time Domain (GMAP-TD) for Weather Radars  

Science Conference Proceedings (OSTI)

The Gaussian model adaptive processing in the time domain (GMAP-TD) method for ground clutter suppression and signal spectral moment estimation for weather radars is presented. The technique transforms the clutter component of a weather radar ...

Cuong M. Nguyen; V. Chandrasekar

2013-11-01T23:59:59.000Z

346

Predictive Models For Time To Acceptance: An Example Using Hurricane Articles in AMS Journals  

Science Conference Proceedings (OSTI)

The authors demonstrate a statistical model for the time it takes a manuscript to be accepted for publication. The manuscript received and accepted dates from published manuscripts with the term hurricane in the title are obtained from the American ...

Robert E. Hodges; James B. Elsner; Thomas H. Jagger

2012-06-01T23:59:59.000Z

347

Search Method for Real-time Knowledge Discovery Modeled on the ...  

ORNL 2011-G00262/jcn UT-B ID 200601732 08.2011 Search Method for Real-time Knowledge Discovery Modeled on the Human Brain Technology Summary A new ...

348

Method for determination of .sup.18 O/.sup.16 O and .sup.2 H/.sup.1 H ratios and .sup.3 H (tritium) concentrations of xylem waters and subsurface waters using time series sampling  

DOE Patents (OSTI)

A method for determination of .sup.18 O/.sup.16 O and .sup.2 H/.sup.1 H ratios and .sup.3 H concentrations of xylem and subsurface waters using time series sampling, insulating sampling chambers, and combined .sup.18 O/.sup.16 O, .sup.2 H/.sup.1 H and .sup.3 H concentration data on transpired water. The method involves collecting water samples transpired from living plants and correcting the measured isotopic compositions of oxygen (.sup.18 O/.sup.16 O) and hydrogen (.sup.2 H/.sup.1 H and/or .sup.3 H concentrations) to account for evaporative isotopic fractionation in the leafy material of the plant.

Smith, Brian (1126 Delaware St., Berkeley, CA 94702); Menchaca, Leticia (1126 Delaware St., Berkeley, CA 94702)

1999-01-01T23:59:59.000Z

349

Biophysical modelling and NDVI time series to project near-term forage supply: spectral analysis aided by wavelet denoising and ARIMA modelling  

Science Conference Proceedings (OSTI)

Point-based biophysical simulation of forage production coupled with 1-km AVHRR NDVI data was used to determine the feasibility of projecting forage conditions 84 days into the future to support stocking decision making for livestock production using ...

M. N. Alhamad; J. Stuth; M. Vannucci

2007-05-01T23:59:59.000Z

350

science_series_map  

NLE Websites -- All DOE Office Websites (Extended Search)

Science Series in CEBAF Center * The Science Series begins at 7:00 PM and typically ends near 8:00 PM * Park in the CEBAF Center parking lot * Enter CEBAF Center through the south...

351

Gibbsianness versus Non-Gibbsianness of time-evolved planar rotor models  

E-Print Network (OSTI)

We study the Gibbsian character of time-evolved planar rotor systems on Z^d, d at least 2, in the transient regime, evolving with stochastic dynamics and starting with an initial Gibbs measure. We model the system by interacting Brownian diffusions, moving on circles. We prove that for small times and arbitrary initial Gibbs measures \

A. C. D. van Enter; W. M. Ruszel

2007-11-22T23:59:59.000Z

352

Modeling shared cache and bus in multi-cores for timing analysis  

Science Conference Proceedings (OSTI)

Timing analysis of concurrent programs running on multi-core platforms is currently an important problem. The key to solving this problem is to accurately model the timing effects of shared resources in multi-cores, namely shared cache and bus. In this ... Keywords: WCET, multi-core, shared bus, shared cache

Sudipta Chattopadhyay; Abhik Roychoudhury; Tulika Mitra

2010-06-01T23:59:59.000Z

353

Stability analysis of T-S fuzzy models for nonlinear multiple time-delay interconnected systems  

Science Conference Proceedings (OSTI)

In this paper, the Takagi-Sugeno (T-S) fuzzy model representation is extended to the stability analysis for nonlinear interconnected systems with multiple time-delays using linear matrix inequality (LMI) theory. In terms of Lyapunov's direct method for ... Keywords: Lyapunov's theory, fuzzy systems, time delay

C. W. Chen; W. L. Chiang; F. H. Hsiao

2004-08-01T23:59:59.000Z

354

Model of hydrogen atom for twisted acceleration-enlarged Newton-Hooke space-times  

E-Print Network (OSTI)

We define the model of hydrogen atom for twist-deformed acceleration-enlarged Newton-Hooke space-time. Further, using time-dependent perturbation theory, we find in first step of iteration procedure the solution of corresponding Schroedinger equation as well as the probability of transition between two different energy-eigenstates.

Marcin Daszkiewicz

2013-12-09T23:59:59.000Z

355

Real Time Physically-Based Modeling and Simulation of Cratering and Fragmentation of Terrain  

Science Conference Proceedings (OSTI)

Cratering and fragmentation of terrain due to eXplosions are the behaviors of interest in this effort. We propose a physically-based approach to model the eXplosion event and the process of terrain fragmentation resulting in the formation of craters. ... Keywords: dynamic terrain, eXplosion simulation, physics-based modeling, real time system, simulation, terrain database

Nabil Rami; Michael D. Proctor

2007-12-01T23:59:59.000Z

356

Model driven middleware: A new paradigm for developing distributed real-time and embedded systems  

Science Conference Proceedings (OSTI)

Distributed real-time and embedded (DRE) systems have become critical in domains such as avionics (e.g., flight mission computers), telecommunications (e.g., wireless phone services), tele-medicine (e.g., robotic surgery), and defense applications (e.g., ... Keywords: CCM: CORBA component model, D&C: Deployment and configuration, MDM: Model driven middleware

Aniruddha Gokhale; Krishnakumar Balasubramanian; Arvind S. Krishna; Jaiganesh Balasubramanian; George Edwards; Gan Deng; Emre Turkay; Jeffrey Parsons; Douglas C. Schmidt

2008-09-01T23:59:59.000Z

357

Condensate system modelling in real time for a training power plant simulator  

Science Conference Proceedings (OSTI)

In this paper, the basis of the models of the condensate water and the air cooled condenser are presented. The models are part of a full scope simulator of a 450 MW combined cycle power plant. The simulator is executed in real time and is intended to ...

Yadira Mendoza-Alegra; Edgardo J. Roldan-Villasana

2011-10-01T23:59:59.000Z

358

Analyzing water supply in future energy systems using the TIMES Integrated Assessment Model (TIAM-FR)  

E-Print Network (OSTI)

Analyzing water supply in future energy systems using the TIMES Integrated Assessment Model (TIAM is required to maintain water supplies while water is essential to produce energy. However, the models and energy generally dealt with them separately, the two resources are highly interconnected. Energy

359

Model order reduction methods for coupled systems in the time domain using Laguerre polynomials  

Science Conference Proceedings (OSTI)

In this paper, based on Laguerre polynomials, we present new methods for model reduction of coupled systems in the time domain. By appropriately selected projection matrices, a reduced order system is produced to retain the topology structure of the ... Keywords: Coupled systems, Function approximation, Laguerre polynomials, Model reduction, Structure preservation

Xiao-Long Wang; Yao-Lin Jiang

2011-10-01T23:59:59.000Z

360

Two-Dimensional Conformal Models of Space-Time and Their Compactification  

E-Print Network (OSTI)

We study geometry of two-dimensional models of conformal space-time based on the group of Moebius transformation. The natural geometric invariants, called cycles, are used to linearise Moebius action. Conformal completion of the space-time is achieved through an addition of a zero-radius cycle at infinity. We pay an attention to the natural condition of non-reversibility of time arrow in order to get a correct compactification in the hyperbolic case.

Vladimir V. Kisil

2006-11-21T23:59:59.000Z

Note: This page contains sample records for the topic "time series models" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Long-time integration methods for mesoscopic models of pattern-forming systems  

Science Conference Proceedings (OSTI)

Spectral methods for simulation of a mesoscopic diffusion model of surface pattern formation are evaluated for long simulation times. Backwards-differencing time-integration, coupled with an underlying Newton-Krylov nonlinear solver (SUNDIALS-CVODE), is found to substantially accelerate simulations, without the typical requirement of preconditioning. Quasi-equilibrium simulations of patterned phases predicted by the model are shown to agree well with linear stability analysis. Simulation results of the effect of repulsive particle-particle interactions on pattern relaxation time and short/long-range order are discussed.

Abukhdeir, Nasser Mohieddin [Department of Chemical Engineering, University of Delaware, Newark, DE (United States); Vlachos, Dionisios G., E-mail: vlachos@udel.ed [Department of Chemical Engineering, University of Delaware, Newark, DE (United States); Katsoulakis, Markos [Department of Mathematics and Statistics, University of Massachusetts, Amherst, MA (United States); Department of Applied Mathematics, University of Crete, Heraklion (Greece); Institute of Applied and Computational Mathematics, Foundation for Research and Technology Hellas, Heraklion (Greece); Plexousakis, Michael [Department of Applied Mathematics, University of Crete, Heraklion (Greece); Institute of Applied and Computational Mathematics, Foundation for Research and Technology Hellas, Heraklion (Greece)

2011-06-20T23:59:59.000Z

362

Fermilab Lecture Series and Events  

NLE Websites -- All DOE Office Websites (Extended Search)

Academic Lecture Series Academic Lecture Series Neutrino Oscillations Schedule Day Speaker Title Location Time March 18 and 25, 2003 (Tuesday) Andre de Gouvea Introduction to Neutrino Oscillations Curia II 10:30 A.M. - noon April 22 and 29, 2003 (Tuesday) Stephen Parke CP Violation in the Neutrino Sector Curia II 10:30 A.M. - noon May 6, 2003 (Tuesday) Boris Kayser The See Saw, and Neutrino Mixing and Oscillation Curia II 10:30 A.M. - noon May 13, 2002 (Tuesday) Boris Kayser Majorana Neutrinos, Majorana Masses, and Double Beta Decay Curia II 10:30 A.M. - noon May 13, 2002 (Tuesday) Boris Kayser Neutrino Puzzles and Leptogenesis Curia II 10:30 A.M. - noon Lattice QCD and the CKM Matrix: What, Why, and When You Should Believe. A series of four lectures reviewing the status and prospects of Lattice QCD

363

Series Transmission Line Transformer  

DOE Patents (OSTI)

A series transmission line transformer is set forth which includes two or more of impedance matched sets of at least two transmissions lines such as shielded cables, connected in parallel at one end ans series at the other in a cascading fashion. The cables are wound about a magnetic core. The series transmission line transformer (STLT) which can provide for higher impedance ratios and bandwidths, which is scalable, and which is of simpler design and construction.

Buckles, Robert A. (Livermore, CA); Booth, Rex (Livermore, CA); Yen, Boris T. (El Cerrito, CA)

2004-06-29T23:59:59.000Z

364

A stochastic model of radiation carcinogenesis: Latent time distributions and their properties  

Science Conference Proceedings (OSTI)

A stochastic model of radiation carcinogenesis is proposed that has much in common with the ideas suggested by M. Pike as early as 1966. The model allows one to obtain a parametric family of substochastic-type distributions for the time of tumor latency that provides a description of the rate of tumor development and the number of affected individuals. With this model it is possible to interpret data on tumor incidence in terms of promotion and progression processes. The basic model is developed for a prolonged irradiation at a constant dose rate and includes short-term irradiation as a special case. A limiting form of the latent time distribution for short-term irradiation at high doses is obtained. This distribution arises in the extreme value theory within the random minima framework. An estimate for the rate of convergence to a limiting distributions is given. Based on the proposed latent time distributions, long-term predictions of carcinogenic risk do not call for information about irradiation dose. As shown by computer simulation studies and real data analysis, the parametric estimation of carcinogenic risk appears to be robust to the loss of statistical information caused by the right-hand censoring of time-to-tumor observations. It seems likely that this property, although revealed by means of a purely empirical procedure, may be useful in selecting a model for the practical purpose of risk prediction. 44 refs., 3 figs., 1 tab.

Klebanov, L.V.; Yakovlev, A.Yu. (St. Petersburg Technical Univ. (Russian Federation)); Rachev, S.T. (Univ. of California, Santa Barbara (United States))

1993-01-01T23:59:59.000Z

365

Modeling and development of the real-time control strategy for parallel hybrid electric urban buses  

Science Conference Proceedings (OSTI)

This paper proposes a feed-forward control model for SWB6105 parallel hybrid electric urban bus (PHEUB) by using Matlab/Simulink. In order to optimize the fuel economy, balance the battery state of charge (SOC), and satisfy the requirements of the vehicle ... Keywords: hybrid powertrain, hybrid system modeling, instantaneous optimization algorithm, logic threshold torque distribution control strategy (LTTDCS), parallel hybrid electric urban bus (PHEUB), real-time control

Yuanjun Huang; Chengliang Yin; Jianwu Zhang

2008-07-01T23:59:59.000Z

366

SERIES B: Operations Research  

E-Print Network (OSTI)

Tokyo Institute of Technology. SERIES B: Operations ... Department of Computer Science, The University of Electro-Communications,. Chofugaoka, Chofu-Shi...

367

Nuclear Science Series: Radiochemistry  

NLE Websites -- All DOE Office Websites (Extended Search)

Radiochemistry Nuclear Science Series: Radiochemistry These volumes are publicly accessible via the Library Catalog or the links below. Question? 667-5809 Email Scope This...

368

Computation of feasible portfolio controlstrategies for an insurance company using a discrete time asset/liability model  

Science Conference Proceedings (OSTI)

A nonlinear discrete time asset/liability model is developed for an insurance company selling investment policies with a guaranteed minimum rate of return and a fixed maturity date. The model accommodates time-dependent investment strategies and transaction ... Keywords: Discrete time asset/liability models, Dynamic financial analysis, Feasible portfolio control, Investment policies with a guaranteed minimum rate of return

C. Frangos; S. A. Zenios; Y. Yavin

2004-08-01T23:59:59.000Z

369

Real-time characterization of partially observed epidemics using surrogate models.  

SciTech Connect

We present a statistical method, predicated on the use of surrogate models, for the 'real-time' characterization of partially observed epidemics. Observations consist of counts of symptomatic patients, diagnosed with the disease, that may be available in the early epoch of an ongoing outbreak. Characterization, in this context, refers to estimation of epidemiological parameters that can be used to provide short-term forecasts of the ongoing epidemic, as well as to provide gross information on the dynamics of the etiologic agent in the affected population e.g., the time-dependent infection rate. The characterization problem is formulated as a Bayesian inverse problem, and epidemiological parameters are estimated as distributions using a Markov chain Monte Carlo (MCMC) method, thus quantifying the uncertainty in the estimates. In some cases, the inverse problem can be computationally expensive, primarily due to the epidemic simulator used inside the inversion algorithm. We present a method, based on replacing the epidemiological model with computationally inexpensive surrogates, that can reduce the computational time to minutes, without a significant loss of accuracy. The surrogates are created by projecting the output of an epidemiological model on a set of polynomial chaos bases; thereafter, computations involving the surrogate model reduce to evaluations of a polynomial. We find that the epidemic characterizations obtained with the surrogate models is very close to that obtained with the original model. We also find that the number of projections required to construct a surrogate model is O(10)-O(10{sup 2}) less than the number of samples required by the MCMC to construct a stationary posterior distribution; thus, depending upon the epidemiological models in question, it may be possible to omit the offline creation and caching of surrogate models, prior to their use in an inverse problem. The technique is demonstrated on synthetic data as well as observations from the 1918 influenza pandemic collected at Camp Custer, Michigan.

Safta, Cosmin; Ray, Jaideep; Lefantzi, Sophia; Crary, David (Applied Research Associates, Arlington, VA); Sargsyan, Khachik; Cheng, Karen (Applied Research Associates, Arlington, VA)

2011-09-01T23:59:59.000Z

370

Testing time symmetry in time series using data compression dictionaries  

E-Print Network (OSTI)

1978). [12] It is a pre?x dictionary: for any codeword w =1 s 2 . . . s L in the dictionary, all pre?xes of w, e.g. ,j ? L are also in the dictionary. Parsing is greedy: search

Kennel, Matthew B

2004-01-01T23:59:59.000Z

371

The N-Burst/G/1 model with heavy-tailed service-times distribution Ronit Nossenson and Hagit Attiya  

E-Print Network (OSTI)

The N-Burst/G/1 model with heavy-tailed service-times distribution Ronit Nossenson and Hagit@cs.technion.ac.il Abstract This study introduces a new analytic queuing model, the N-Burst/G/1 model with heavy; this relies on calculating the waiting-time distribu- tion in the M/G/1 model with heavy-tailed service

Attiya, Hagit

372

Improvement of Auto-Regressive Integrated Moving Average models using Fuzzy logic and Artificial Neural Networks (ANNs)  

Science Conference Proceedings (OSTI)

Time series forecasting is an active research area that has drawn considerable attention for applications in a variety of areas. Auto-Regressive Integrated Moving Average (ARIMA) models are one of the most important time series models used in financial ... Keywords: Artificial Neural Networks (ANNs), Auto-Regressive Integrated Moving Average (ARIMA), Exchange rate, Financial markets, Fuzzy logic, Time series forecasting

Mehdi Khashei; Mehdi Bijari; Gholam Ali Raissi Ardali

2009-01-01T23:59:59.000Z

373

Real-time modeling of complex atmospheric releases in urban areas  

Science Conference Proceedings (OSTI)

If a nuclear installation in or near an urban area has a venting, fire, or explosion, airborne radioactivity becomes the major concern. Dispersion models are the immediate tool for estimating the dose and contamination. Responses in urban areas depend on knowledge of the amount of the release, representative meteorological data, and the ability of the dispersion model to simulate the complex flows as modified by terrain or local wind conditions. A centralized dispersion modeling system can produce realistic assessments of radiological accidents anywhere in a country within several minutes if it is computer-automated. The system requires source-term, terrain, mapping and dose-factor databases, real-time meteorological data acquisition, three-dimensional atmospheric transport and dispersion models, and experienced staff. Experience with past responses in urban areas by the Atmospheric Release Advisory Capability (ARAC) program at Lawrence Livermore National Laboratory illustrate the challenges for three-dimensional dispersion models.

Baskett, R.L. [EG and G Energy Measurements, Inc., Pleasanton, CA (United States); Ellis, J.S.; Sullivan, T.J. [Lawrence Livermore National Lab., CA (United States)

1994-08-01T23:59:59.000Z

374

Econometric Modelling of World Oil Supplies: Terminal Price and the Time to Depletion  

E-Print Network (OSTI)

demand, it is dependent on the world real interest rate and the total life-time stock of oil resources, as well as on the marginal extraction and scarcity cost parameters. The theoretical predictions of this model are evaluated using data on the cost...

Mohaddes, Kamiar

2012-03-02T23:59:59.000Z

375

Accurate Modeling and Prediction of Energy Availability in Energy Harvesting Real-Time Embedded Systems  

E-Print Network (OSTI)

on the type of energy harvesting technology, ECM1 can be either DC/DC or AC/DC converter. ECM2 is usually a DC/DCAccurate Modeling and Prediction of Energy Availability in Energy Harvesting Real-Time Embedded}@binghamton.edu Abstract -- Energy availability is the primary subject that drives the research innovations in energy

Qiu, Qinru

376

A Description of the Air Force Real-Time Nephanalysis Model  

Science Conference Proceedings (OSTI)

The Air Force Global Weather Central (AFGWC) Real-Time Nephanalysis (RTNEPH) is an automated cloud model that produces a 48-km gridded analysis of cloud amount, cloud type, and cloud height. Its primary input is imagery from polar-orbiting ...

Thomas M. Hamill; Robert P. D'Entremont; James T. Buntin

1992-06-01T23:59:59.000Z

377

Exciting understanding in Pompeii through on-site parallel interaction with dual time virtual models  

Science Conference Proceedings (OSTI)

Communication effectiveness and reconstruction validation are two important goals faced by archaeologists. This paper shows how these targets can be reached more easily by means of a mobile and user-centric fruition system designed with both the visitor's ... Keywords: connectivity, dual-time modelling, interactivity, interface, multimedia, pompeii, reconstruction, virtual archaeology

Daniela Scagliarini; Antonella Coralini; Erika Vecchietti; Tullio Salmon Cinotti; Luca Roffia; Stefania Galasso; Maurizio Malavasi; Massimiliano Pigozzi; Enrico Romagnoli; Fabio Sforza

2001-11-01T23:59:59.000Z

378

Bulk viscous fluid hypersurface - homogeneous cosmological models with time varying G and ?  

Science Conference Proceedings (OSTI)

Hypersurface - homogeneous cosmological models containing a bulk viscous fluid with time varying G and ? have been presented. We have shown that the field equations are solvable for any arbitrary cosmic scale function. The viscosity coefficient ... Keywords: bulk viscosity, hypersurface - homogeneous, variable G and ?. LATEX

Shri Ram; M. K. Verma

2010-02-01T23:59:59.000Z

379

Run-time Modeling and Estimation of Operating System Power Consumption  

E-Print Network (OSTI)

software power evaluation, as well as power management (e.g. dynamic thermal control and equal energy of a commercial OS across a wide spectrum of applications to understand OS energy profiles and then proposes to track run- time OS energy profiles, the proposed routine level OS power model offers superior accuracy

John, Lizy Kurian

380

A multi-category inter-purchase time model based on hierarchical Bayesian theory  

Science Conference Proceedings (OSTI)

Because of recent diversity in consumer demands and the decrease in popularity of mass media, one-to-one database marketing is being increasingly used by companies to increase their competitiveness. Many studies have addressed the issue of inter-purchase ... Keywords: Catalog shopping, Hierarchical Bayesian model, Inter-purchase time

Ruey-Shan Guo

2009-04-01T23:59:59.000Z

Note: This page contains sample records for the topic "time series models" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Two-Time-Level Semi-Lagrangian Modeling of Precipitating Clouds  

Science Conference Proceedings (OSTI)

This paper discusses two-time-level semi-Lagrangian approximations for the bulk warm-rain microphysics embedded in the framework of an anelastic cloud model. The central theoretical issue is a semi-Lagrangian integration of the rain-evolution ...

Wojciech W. Grabowski; Piotr K. Smolarkiewicz

1996-03-01T23:59:59.000Z

382

A real-time emergency response workstation using a 3-D numerical model initialized with sodar  

Science Conference Proceedings (OSTI)

Many emergency response dispersion modeling systems provide simple Gaussian models driven by single meteorological tower inputs to estimate the downwind consequences from accidental spills or stack releases. Complex meteorological or terrain settings demand more sophisticated resolution of the three-dimensional structure of the atmosphere to reliably calculate plume dispersion. Mountain valleys and sea breeze flows are two common examples of such settings. To address these complexities, the authors have implemented the three-dimensional diagnostic MATHEW mass-adjusted wind field and ADPIC particle-in-cell dispersion models on a workstation for use in real-time emergency response modeling. MATHEW/ADPIC have shown their utility in a variety of complex settings over the last 15 years within the Department of Energy`s Atmospheric Release Advisory Capability (ARAC) project. The models are initialized using an array of surface wind measurements from meteorological towers coupled with vertical profiles from an acoustic sounder (sodar). The workstation automatically acquires the meteorological data every 15 minutes. A source term is generated using either defaults or a real-time stack monitor. Model outputs include contoured isopleths displayed on site geography or plume densities shown over 3-D color shaded terrain. The models are automatically updated every 15 minutes to provide the emergency response manager with a continuous display of potentially hazardous ground-level conditions if an actual release were to occur. Model run time is typically less than 2 minutes on 6 megaflop ({approximately}30 MIPS) workstations. Data acquisition, limited by dial-up modem communications, requires 3 to 5 minutes.

Lawver, B.S.; Sullivan, T.J. [Lawrence Livermore National Lab., CA (US); Baskett, R.L. [EG& G Energy Measurements, Inc., Pleasanton, CA (US)

1993-01-28T23:59:59.000Z

383

Real-time road traffic forecasting using regime-switching space-time models and adaptive LASSO  

Science Conference Proceedings (OSTI)

Smart transportation technologies require real-time traffic prediction to be both fast and scalable to full urban networks. We discuss a method that is able to meet this challenge while accounting for nonlinear traffic dynamics and space-time dependencies ... Keywords: adaptive LASSO, real-time predictions, threshold regressions, traffic forecasting

Yiannis Kamarianakis; Wei Shen; Laura Wynter

2012-07-01T23:59:59.000Z

384

Discrete-Time Block Models for Transmission Line Channels: Static and Doubly Selective Cases  

E-Print Network (OSTI)

Most methodologies for modeling Transmission Line (TL) based channels define the input-output relationship in the frequency domain (FD) and handle the TL resorting to a two-port network (2PN) formalism. These techniques have not yet been formally mapped into a discrete-time (DT) block model, which is useful to simulate and estimate the channel response as well as to design optimal precoding strategies. TL methods also fall short when they are applied to Time Varying (TV) systems, such as the power line channel. The objective of this paper is to establish if and how one can introduce a DT block model for the Power Line Channel. We prove that it is possible to use Lifting and Trailing Zeros (L&TZ) techniques to derive a DT block model that maps the TL-based input-output description directly in the time domain (TD) block channel model. More specifically, we find an interesting relationship between the elements of an ABCD matrix, defined in the FD, and filtering kernels that allow an elegant representation of...

Galli, Stefano

2011-01-01T23:59:59.000Z

385

Argonne CNM: 2012 Colloquium Series  

NLE Websites -- All DOE Office Websites (Extended Search)

2 Colloquium Series 2 Colloquium Series 2013 | 2012 | 2011 | 2010 | 2009 | 2008 | 2007 | Date Title Special Colloquium December 13, 2012 "Pathways to Complex Matter Far-Away-From Equilibrium: Developing Spatiotemporal Tools," by Gopal Shenoy, Argonne National Laboratory, hostged by Daniel Lopez Abstract: From the Big Bang to the coming of humankind, every manifestation of nature has exhibited processes far-away-from equilibrium leading to increasingly complex structural orders from geological to atomic length and time scales. Examples include the evolution of galaxies, hurricanes, stars, and planets; prebiotic reactions; cyclical reactions; photosynthesis; and life itself. The organizational spatiotemporal evolution in soft, hard, and biological matter also follows the same path. It begins from a far-from-equilibrium state and develops over time into organizations with length scales between atoms and small molecules on the one hand and mesoscopic matter on the other.

386

Time-dependent 2-D modeling of edge plasma transport with high intermittency due to blobs  

SciTech Connect

The results on time-dependent 2-D fluid modeling of edge plasmas with non-diffusive intermittent transport across the magnetic field (termed cross-field) based on the novel macro-blob approach are presented. The capability of this approach to simulate the long temporal evolution ({approx}0.1 s) of the background plasma and simultaneously the fast spatiotemporal dynamics of blobs ({approx}10{sup -4} s) is demonstrated. An analysis of a periodic sequence of many macro-blobs (PSMB) is given showing that the resulting plasma attains a dynamic equilibrium. Plasma properties in the dynamic equilibrium are discussed. In PSMB modeling, the effect of macro-blob generation frequency on edge plasma parameters is studied. Comparison between PSMB modeling and experimental profile data is given. The calculations are performed for the same plasma discharge using two different models for anomalous cross-field transport: time-average convection and PSMB. Parametric analysis of edge plasma variation with transport coefficients in these models is presented. The capability of the models to accurately simulate enhanced transport due to blobs is compared. Impurity dynamics in edge plasma with macro-blobs is also studied showing strong impact of macro-blob on profiles of impurity charge states caused by enhanced outward transport of high-charge states and simultaneous inward transport of low-charge states towards the core. Macro-blobs cause enhancement of sputtering rates, increase radiation and impurity concentration in plasma, and change erosion/deposition patterns.

Pigarov, A. Yu.; Krasheninnikov, S. I. [University of California at San Diego, La Jolla, California 92093 (United States); Rognlien, T. D. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)

2012-07-15T23:59:59.000Z

387

Computational Modeling and Real-Time Control of Patient-Specific Laser Treatment of Cancer  

E-Print Network (OSTI)

AbstractAn adaptive feedback control system is presented which employs a computational model of bioheat transfer in living tissue to guide, in real-time, laser treatments of prostate cancer monitored by magnetic resonance thermal imaging. The system is built on what can be referred to as cyberinfrastructurea complex structure of high-speed network, large-scale parallel computing devices, laser optics, imaging, visualizations, inverse-analysis algorithms, mesh generation, and control systems that guide laser therapy to optimally control the ablation of cancerous tissue. The computational system has been successfully tested on in vivo, canine prostate. Over the course of an 18 min laser-induced thermal therapy performed at M.D. Anderson Cancer Center (MDACC) in Houston, Texas, the computational models were calibrated to intra-operative real-time thermal imaging treatment data and the calibrated models controlled the bioheat transfer to within 5 C of the predetermined treatment plan. The computational arena is in Austin, Texas and managed at the Institute for Computational Engineering and Sciences (ICES). The system is designed to control the bioheat transfer remotely while simultaneously providing real-time remote visualization of the on-going treatment. Post-operative histology of the canine prostate reveal that the damage region was within the targeted 1.2 cm diameter treatment objective. KeywordsHyperthermia, Real-time computing, Medical imaging, Cancer treatment, Cyberinfrastructure, PDE

unknown authors

2009-01-01T23:59:59.000Z

388

Intrinsic dynamics of heart regulatory systems on short time-scales: from experiment to modelling  

E-Print Network (OSTI)

We discuss open problems related to the stochastic modeling of cardiac function. The work is based on an experimental investigation of the dynamics of heart rate variability (HRV) in the absence of respiratory perturbations. We consider first the cardiac control system on short time scales via an analysis of HRV within the framework of a random walk approach. Our experiments show that HRV on timescales of less than a minute takes the form of free diffusion, close to Brownian motion, which can be described as a non-stationary process with stationary increments. Secondly, we consider the inverse problem of modeling the state of the control system so as to reproduce the experimentally observed HRV statistics of. We discuss some simple toy models and identify open problems for the modelling of heart dynamics.

Khovanov, I A; McClintock, P V E; Stefanovska, A

2009-01-01T23:59:59.000Z

389

A multiple-relaxation-time lattice Boltzmann model for convection heat transfer in porous media  

E-Print Network (OSTI)

In this paper, a multiple-relaxation-time (MRT) lattice Boltzmann (LB) model is developed for simulating convection heat transfer in porous media at the representative elementary volume scale. In the model, a MRT-LB equation is used to simulate the flow field, while another MRT-LB equation is employed to simulate the temperature field. The effect of the porous media is considered by introducing the porosity into the equilibrium moments, and adding a forcing term to the MRT-LB equation of the flow field in the moment space. The proposed MRT-LB model is validated by numerical simulations of several two-dimensional convection problems in porous media. The numerical results predicted by the present MRT-LB model agree well with those reported in the literature.

Q. Liu; Y. L. He; Q. Li

2013-08-09T23:59:59.000Z

390

A generalized linear-quadratic model incorporating reciprocal time pattern of radiation damage repair  

Science Conference Proceedings (OSTI)

Purpose: It has been conventionally assumed that the repair rate for sublethal damage (SLD) remains constant during the entire radiation course. However, increasing evidence from animal studies suggest that this may not the case. Rather, it appears that the repair rate for radiation-induced SLD slows down with increasing time. Such a slowdown in repair would suggest that the exponential repair pattern would not necessarily accurately predict repair process. As a result, the purpose of this study was to investigate a new generalized linear-quadratic (LQ) model incorporating a repair pattern with reciprocal time. The new formulas were tested with published experimental data. Methods: The LQ model has been widely used in radiation therapy, and the parameter G in the surviving fraction represents the repair process of sublethal damage with T{sub r} as the repair half-time. When a reciprocal pattern of repair process was adopted, a closed form of G was derived analytically for arbitrary radiation schemes. The published animal data adopted to test the reciprocal formulas. Results: A generalized LQ model to describe the repair process in a reciprocal pattern was obtained. Subsequently, formulas for special cases were derived from this general form. The reciprocal model showed a better fit to the animal data than the exponential model, particularly for the ED50 data (reduced {chi}{sup 2}{sub min} of 2.0 vs 4.3, p = 0.11 vs 0.006), with the following gLQ parameters: {alpha}/{beta} = 2.6-4.8 Gy, T{sub r} = 3.2-3.9 h for rat feet skin, and {alpha}/{beta} = 0.9 Gy, T{sub r} = 1.1 h for rat spinal cord. Conclusions: These results of repair process following a reciprocal time suggest that the generalized LQ model incorporating the reciprocal time of sublethal damage repair shows a better fit than the exponential repair model. These formulas can be used to analyze the experimental and clinical data, where a slowing-down repair process appears during the course of radiation therapy.

Huang, Zhibin; Mayr, Nina A.; Lo, Simon S.; Wang, Jian Z.; Jia Guang; Yuh, William T. C.; Johnke, Roberta [Department of Radiation Oncology, East Carolina University, Greenville, North Carolina 27834 (United States); Department of Radiation Oncology, Ohio State University, Columbus, Ohio 43210 (United States); Department of Radiation Oncology, University Hospitals Case Medical Center, Case Western Reserve University, Cleveland, Ohio 44106 (United States); Department of Radiation Oncology, Ohio State University, Columbus, Ohio 43210 (United States); Department of Radiology, Ohio State University, Columbus, Ohio 43210 (United States); Department of Radiation Oncology, East Carolina University, Greenville, North Carolina, 27834 (United States)

2012-01-15T23:59:59.000Z

391

Dark energy model with variable $q$ and $?$ in LRS Bianchi-II space-time  

E-Print Network (OSTI)

The present study deals with spatial homogeneous and anisotropic locally rotationally symmetric (LRS) Bianchi-II dark energy model in general relativity. The Einstein's field equations have been solved exactly by taking into account the proportionality relation between one of the components of shear scalar $(\\sigma^{1}_{1})$ and expansion scalar $(\\vartheta)$, which, for some suitable choices of problem parameters, yields time dependent equation of state (EoS) and deceleration parameter (DP), representing a model which generates a transition of universe from early decelerating phase to present accelerating phase. The physical and geometrical behavior of universe have been discussed in detail.

Bijan Saha; Anil Kumar Yadav

2011-10-21T23:59:59.000Z

392

SBOT NAICS Series  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

SBOT NAICS Series 213112 Support Activities for Oil and Gas Operations NATIONAL ENERGY TECHNOLOGY LAB Larry Sullivan (412) 386-6115 larry.sullivan@netl.doe.gov NATIONAL ENERGY...

393

Quasi-explicit time-integration schemes for dynamic fracture with set-valued cohesive zone models  

Science Conference Proceedings (OSTI)

We investigate quasi-explicit time-integration schemes for solving dynamic fracture problems with set-valued cohesive zone models. These schemes combine a central difference time-integration scheme and a partially implicit and lumped treatment of the ... Keywords: Cohesive zone model, Finite elements, Time-integration scheme

D. Doyen; A. Ern; S. Piperno

2013-08-01T23:59:59.000Z

394

Essays on Nonparametric Series Estimation with Application to Financial Econometrics  

E-Print Network (OSTI)

This dissertation includes two essays. In the first essay, I proposed an alternative estimator for multivariate densities. This estimator can be characterized as a transformation based estimator. The first stage estimates each marginal density separately. In the second stage, the joint density of estimated marginal cumulative distribution functions (CDF) are approximated by the exponential series estimator. The final estimate is then obtained as the product of the marginal densities and the joint density estimated in the second stage. Extensive Monte Carlo studies show the proposed estimator outperforms kernel estimators in joint density and tail distribution estimation. An illustrative example on estimating the conditional copula density between S & P 500 and FTSE 100 given Hangseng and Nikkei 225 is also discussed. In the second essay, I extended the semiparametric model by Chen and Fan [X. Chen, Y. Fan, Estimation of copula-based semiparametric time series models, Journal of Econometrics 130 (2006) 307-335], and studied a class of univariate copula-based nonparametric stationary Markov models in which the copulas and the marginal distributions are estimated nonparametrically. In particular, I focused on the stationary Markov process of order 1 with continuous state space because it has the beta-mixing property for the analysis of weakly dependent processes. The copula density functions for time series models are approximated by the series estimate on sieve spaces. In this study, a finite dimensional linear space spanned by a sequence of power functions is treated as the sieve space where the estimation space of the copula density function is based. This sieve series estimator can be characterized as the exponential series estimator under mild smoothness conditions. By using the beta-mixing properties, I showed that the copula density function approximated by the exponential series estimator for stationary first-order Markov processes has the same convergence rate as the i.i.d. data. The Monte Carlo simulations show that the proposed estimator outperforms the kernel estimator in the conditional density estimation, except for the Frank copula-based Markov model. In addition, the proposed estimator considerably dominates the the kernel estimator when used in the one-step-ahead forecast.

Chang, Meng-Shiuh

2011-08-01T23:59:59.000Z

395

From Measurements to Models: Cross-Comparison of Measured and...  

NLE Websites -- All DOE Office Websites (Extended Search)

cloud conditions were clustered into 32 regimes or states resulting in time series animations of global atmospheric conditions. These analyses establish a set of modeled...

396

A real-time monitoring/emergency response modeling workstation for a tritium facility  

SciTech Connect

At Lawrence Livermore National Laboratory (LLNL) we developed a real-time system to monitor two stacks on our tritium handling facility. The monitors transmit the stack data to a workstation which computes a 3D numerical model of atmospheric dispersion. The workstation also collects surface and upper air data from meteorological towers and a sodar. The complex meteorological and terrain setting in the Livermore Valley demands more sophisticated resolution of the three-dimensional structure of the atmosphere to reliably calculate plume dispersion than afforded by Gaussian models. We experience both mountain valley and sea breeze flows. To address these complexities, we have implemented the three-dimensional diagnostic MATHEW mass-adjusted wind field and ADPIC particle-in-cell dispersion models on the workstation for use in real-time emergency response modeling. Both MATHEW and ADPIC have shown their utility in a variety of complex settings over the last 15 years within the Department of Energy`s Atmospheric Release Advisory Capability (ARAC[1,2]) project.

Lawver, B.S.; Sims, J.M. [Lawrence Livermore National Lab., CA (United States); Baskett, R.L. [EG and G Energy Measurements, Inc., Pleasanton, CA (United States)

1993-07-01T23:59:59.000Z

397

Extreme Value Statistics of the Total Energy in an Intermediate-Complexity Model of the Midlatitude Atmospheric Jet. Part I: Stationary Case  

Science Conference Proceedings (OSTI)

A baroclinic model of intermediate complexity for the atmospheric jet at middle latitudes is used as a stochastic generator of atmosphere-like time series. In this case, time series of the total energy of the system are considered. Statistical ...

Mara Felici; Valerio Lucarini; Antonio Speranza; Renato Vitolo

2007-07-01T23:59:59.000Z

398

A cyclic time-dependent Markov process to model daily patterns in wind turbine power production  

E-Print Network (OSTI)

Wind energy is becoming a top contributor to the renewable energy mix, which raises potential reliability issues for the grid due to the fluctuating nature of its source. To achieve adequate reserve commitment and to promote market participation, it is necessary to provide models that can capture daily patterns in wind power production. This paper presents a cyclic inhomogeneous Markov process, which is based on a three-dimensional state-space (wind power, speed and direction). Each time-dependent transition probability is expressed as a Bernstein polynomial. The model parameters are estimated by solving a constrained optimization problem: The objective function combines two maximum likelihood estimators, one to ensure that the Markov process long-term behavior reproduces the data accurately and another to capture daily fluctuations. A convex formulation for the overall optimization problem is presented and its applicability demonstrated through the analysis of a case-study. The proposed model is capable of r...

Scholz, Teresa; Estanqueiro, Ana

2013-01-01T23:59:59.000Z

399

Test Cases for Wind Power Plant Dynamic Models on Real-Time Digital Simulator: Preprint  

DOE Green Energy (OSTI)

The objective of this paper is to present test cases for wind turbine generator and wind power plant models commonly used during commissioning of wind power plants to ensure grid integration compatibility. In this paper, different types of wind power plant models based on the Western Electricity Coordinating Council Wind Generator Modeling Group's standardization efforts are implemented on a real-time digital simulator, and different test cases are used to gauge their grid integration capability. The low-voltage ride through and reactive power support capability and limitations of wind turbine generators under different grid conditions are explored. Several types of transient events (e.g., symmetrical and unsymmetrical faults, frequency dips) are included in the test cases. The differences in responses from different types of wind turbine are discussed in detail.

Singh, M.; Muljadi, E.; Gevorgian, V.

2012-06-01T23:59:59.000Z

400

Minisuperspace model of Machian Resolution of Problem of Time. I. Isotropic Case  

E-Print Network (OSTI)

A local resolution to the Problem of Time that is Machian and was previously demonstrated for various relational mechanics models is here shown to work for a more widely studied quantum cosmological model. Namely, closed isotropic minisuperspace GR with minimally-coupled scalar field matter. This uses work firstly along the lines of Barbour's at the classical level. Secondly, it uses a Machianized version of the Semiclassical Approach to Quantum Cosmology. Finally, it uses a combined Machianized version of a combined Semiclassical Histories Timeless Records scheme along the lines of Halliwell's work. This program's goal is the treatment of Halliwell--Hawking type inhomogeneous perturbations about the present paper's model, drawing also qualitatively from the relational mechanics examples since these have nontrivial notions of inhomogeneity/structure (clumping) as well as nontrivial linear constraints.

Edward Anderson

2013-07-07T23:59:59.000Z

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401

A One-Dimensional Time-Dependent Model for the Vertical Stratification of the Upper Arctic Ocean  

Science Conference Proceedings (OSTI)

A one-dimensional time-dependent model of the upper Arctic Ocean is presented. It describes the circulation above a dynamically passive reservoir of Atlantic water. The model is driven by freshwater runoff from land, ice production and export, ...

Gran Bjrk

1989-01-01T23:59:59.000Z

402

Ions and Precipitation Charging in Warm and Cold Clouds as Simulated in One-Dimensional Time-Dependent Models  

Science Conference Proceedings (OSTI)

One-dimensional time-dependent models of warm and cold clouds were constructed to test the electrical and precipitation development in the presence of a variety of charge separation mechanisms. The, models simulate charging by ion diffusion, the ...

I. Tzur; Z. Levin

1981-11-01T23:59:59.000Z

403

Demand Response-Enabled Model Predictive HVAC Load Control in Buildings using Real-Time Electricity Pricing.  

E-Print Network (OSTI)

??A practical cost and energy efficient model predictive control (MPC) strategy is proposed for HVAC load control under dynamic real-time electricity pricing. The MPC strategy (more)

Avci, Mesut

2013-01-01T23:59:59.000Z

404

Photon and Neutrino Spectra of Time-Dependent Photospheric Models of Gamma-Ray Bursts  

E-Print Network (OSTI)

Thermal photons from the photosphere may be the primary source of the observed prompt emission of gamma-ray bursts (GRBs). In order to produce the observed non-thermal spectra, some kind of dissipation mechanism near the photosphere is required. In this paper we numerically simulate the evolution of the photon spectrum in a relativistically expanding shell with a time-dependent numerical code. We consider two basic models. One is a leptonic model, where a dissipation mechanism heats the thermal electrons maintaining their high temperature. The other model involves a cascade process induced by $pp$($pn$)-collisions which produce high-energy electrons, modify the thermal spectrum, and emit neutrinos. The qualitative properties of the photon spectra are mainly determined by the optical depth at which the dissipation mechanism sets in. Too large optical depths lead to a broad and curved spectrum contradicting the observations, while for optical depths smaller than unity the spectral hardness becomes softer than observed. A significant shift of the spectral peak energy to higher energies due to a large energy injection can lead to an overly broad spectral shape. We show ideal parameter ranges for which these models are able to reproduce the observed spectra. For the $pn$-collision model, the neutrino fluence in the 10-100 GeV range is well above the atmospheric neutrino fluence, but its detection is challenging for presently available detectors.

K. Asano; P. Mszros

2013-08-16T23:59:59.000Z

405

Analysis Of Residence Time Distribution Of Fluid Flow By Axial Dispersion Model  

Science Conference Proceedings (OSTI)

Radioactive tracer {sup 82}Br in the form of KBr-82 with activity {+-} 1 mCi has been injected into steel pipeline to qualify the extent dispersion of water flowing inside it. Internal diameter of the pipe is 3 in. The water source was originated from water tank through which the water flow gravitically into the pipeline. Two collimated sodium iodide detectors were used in this experiment each of which was placed on the top of the pipeline at the distance of 8 and 11 m from injection point respectively. Residence time distribution (RTD) curves obtained from injection of tracer are elaborated numerically to find information of the fluid flow properties. The transit time of tracer calculated from the mean residence time (MRT) of each RTD curves is 14.9 s, therefore the flow velocity of the water is 0.2 m/s. The dispersion number, D/uL, for each RTD curve estimated by using axial dispersion model are 0.055 and 0.06 respectively. These calculations are performed after fitting the simulated axial dispersion model on the experiment curves. These results indicated that the extent of dispersion of water flowing in the pipeline is in the category of intermediate.

Sugiharto [Department of Physics, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, Jl. Ganesha 10, Bandung 40132 (Indonesia); Centre for Applications of Isotopes and Radiation Technology-National Nuclear Energy Agency, Jl. Lebak Bulus Raya No. 49, Jakarta 12440 (Indonesia); Su'ud, Zaki; Kurniadi, Rizal; Waris, Abdul [Centre for Applications of Isotopes and Radiation Technology-National Nuclear Energy Agency, Jl. Lebak Bulus Raya No. 49, Jakarta 12440 (Indonesia); Abidin, Zainal [Department of Physics, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, Jl. Ganesha 10, Bandung 40132 (Indonesia)

2010-12-23T23:59:59.000Z

406

Time dependent modelisation of TeV blazars by a stratified jet model  

E-Print Network (OSTI)

We present a new time-dependent inhomogeneous jet model of non-thermal blazar emission. Ultra-relativistic leptons are injected at the base of a jet and propagate along it. We assume continuous reacceleration and cooling, producing a relativistic quasi-maxwellian (or "pile-up") particle energy distribution. The synchrotron and Synchrotron-Self Compton jet emissivity are computed at each altitude. Klein-Nishina effects as well as intrinsic gamma-gamma absorption are included in the computation. Due to the pair production optical depth, considerable particle density enhancement can occur, particularly during flaring states.Time-dependent jet emission can be computed by varying the particle injection, but due to the sensitivity of pair production process, only small variations of the injected density are required during the flares. The stratification of the jet emission, together with a pile-up distribution, allows significantly lower bulk Lorentz factors, compared to one-zone models. Applying this model to the case of PKS 2155-304 and its big TeV flare observed in 2006, we can reproduce simultaneously the average broad band spectrum of this source from radio to TeV, as well as TeV light curve of the flare with bulk Lorentz factor lower than 15.

Timoth Boutelier; Gilles Henri; Pierre-Olivier Petrucci

2008-10-01T23:59:59.000Z

407

A Stochastic Stick - Slip Model Linking Crustal Shear Strength and Earthquake Interevent Times  

E-Print Network (OSTI)

The current understanding of the earthquake interevent times distribution (ITD) is incomplete. The Weibull distribution is often used to model the earthquake ITD. We link the earthquake ITD on single faults with the Earth's crustal shear strength distribution by means of a phenomenological stick - slip model. We obtain Weibull ITD for power-law stress accumulation, i.e., $\\sigma(t) = \\alpha t^{\\beta}$, where $\\beta >0$ for single faults or systems with homogeneous strength statistics. We show that logarithmic stress accumulation leads to the log-Weibull ITD. For the Weibull ITD, we prove that (i) $m= \\beta m_s$, where $m$ and $m_s$ are, respectively, the ITD and crustal shear strength Weibull moduli and (ii) the time scale $\\tau_s = (S_s/\\alpha)^{1/\\beta}$ where $S_s$ is the scale of crustal shear strength. We generalize the ITD model for fault systems. We investigate deviations of the ITD tails from the Weibull due to sampling bias, magnitude selection, and non-homogeneous strength parameters. Assuming the G...

Hristopulos, Dionissios T

2012-01-01T23:59:59.000Z

408

Distinguished Lecturers Series  

NLE Websites -- All DOE Office Websites (Extended Search)

Past Seminars Past Seminars Lawrence Berkeley National Laboratory Environmental Energy Technologies Division Distinguished Lecture Series Environmental Energy Technologies Division Distinguished Lecture Series Andrew Hargadon October 22, 2012 Long Fuse, Big Bang: Thomas Edison, Electricity, and the Locus of Innovation Andrew Hargadon Charles J. Soderquist Chair in Entrepreneurship Professor of Technology Management at the Graduate School of Management University of California, Davis John Spengler June 18, 2012 Climate Change Hits Home: Impacts on the Built Environment and Health John Spengler Akira Yamaguchi Professor of Environmental Health & Human Habitation Harvard School of Public Health and Director of the Sustainability and Environmental Management Program Harvard Extension School

409

Fission time-scale in experiments and in multiple initiation model  

Science Conference Proceedings (OSTI)

Rate of fission for highly-excited nuclei is affected by the viscose character of the systemmotion in deformation coordinates as was reported for very heavy nuclei with Z{sub C} > 90. The long time-scale of fission can be described in a model of 'fission by diffusion' that includes an assumption of the overdamped diabatic motion. The fission-to-spallation ratio at intermediate proton energy could be influenced by the viscosity, as well. Within a novel approach of the present work, the cross examination of the fission probability, time-scales, and pre-fission neutron multiplicities is resulted in the consistent interpretation of a whole set of the observables. Earlier, different aspects could be reproduced in partial simulations without careful coordination.

Karamian, S. A., E-mail: karamian@nrmail.jinr.ru [Joint Institute for Nuclear Research (Russian Federation)

2011-12-15T23:59:59.000Z

410

Langevin model for real-time Brownian dynamics of interacting nanodefects in irradiated metals  

SciTech Connect

In situ real-time electron microscope observations of metals irradiated with ultrahigh-energy electrons or energetic ions show that the dynamics of microstructural evolution in these materials is strongly influenced by long-range elastic interactions between mobile nanoscale radiation defects. Treating long-range interactions is also necessary for modeling microstructures formed in ex situ high-dose-rate ion-beam irradiation experiments, and for interpolating the ion-beam irradiation data to the low-dose-rate limit characterizing the neutron irradiation environments of fission or fusion power plants. We show that simulations, performed using an algorithm where nanoscale radiation defects are treated as interacting Langevin particles, are able to match and explain the real-time dynamics of nanodefects observed in in situ electron microscope experiments.

Dudarev, S. L. [EURATOM/CCFE Fusion Association, Culham Centre for Fusion Energy, Abingdon, Oxfordshire OX14 3DB (United Kingdom); Gilbert, M. R. [EURATOM/CCFE Fusion Association, Culham Centre for Fusion Energy, Abingdon, Oxfordshire OX14 3DB (United Kingdom); Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Arakawa, K. [Research Center for Ultra-High Voltage Electron Microscopy, Osaka University, 7-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Okinawa Institute of Science and Technology, Kunigami, Okinawa 904-0411 (Japan); CREST, JST, 5 Sanbancho, Chiyoda-ku, Tokyo 102-0075 (Japan); Mori, H. [Research Center for Ultra-High Voltage Electron Microscopy, Osaka University, 7-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Yao, Z. [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Department of Mechanical and Materials Engineering, Queen's University, Nicol Hall, 60 Union Street, Kingston, Ontario, K7L 3N6 (Canada); Jenkins, M. L. [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Derlet, P. M. [Condensed Matter Theory Group, Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland)

2010-06-01T23:59:59.000Z

411

Modeling and Analysis of Load and Time Dependent Software Rejuvenation Policies  

E-Print Network (OSTI)

Due to repeated and potentially faulty usage of continuously running client-server type software systems by many clients, such software "ages" with time and eventually fails. Huang et. al. proposed a technique called "software rejuvenation" [3] in which the software is periodically stopped and then restarted in a "robust" state after proper maintenance. This "renewal " of software prevents, or at least postpones, the crash failure. In this paper, we present a quantitative analysis of two software rejuvenation policies. The first one considers only the ageing behaviour of the system by time, while the second one considers the actual load of the system as well. The behaviour of the system is represented through a Markov Regenerative Stochastic Petri Net (MRSPN) model. Numerical analysis of the system performance regarding the probability of successful service of clients is provided. Keywords: Continuously running client-server software systems, Software rejuvenation, Markov Regenerati...

S. Garg; A. Pfening; A. Puliafito; M. Telek; K. S. Trivedi

1996-01-01T23:59:59.000Z

412

Fast History Matching of Time-Lapse Seismic and Production-Data for High Resolution Models  

E-Print Network (OSTI)

Seismic data have been established as a valuable source of information for the construction of reservoir simulation models, most commonly for determination of the modeled geologic structure, and also for population of static petrophysical properties (e.g. porosity, permeability). More recently, the availability of repeated seismic surveys over the time scale of years (i.e., 4D seismic) has shown promising results for the qualitative determination of changes in fluid phase distributions and pressure required for determination of areas of bypassed oil, swept volumes and pressure maintenance mechanisms. Quantitatively, and currently the state of the art in reservoir model characterization, 4D seismic data have proven distinctively useful for the calibration of geologic spatial variability which ultimately contributes to the improvement of reservoir development and management strategies. Among the limited variety of techniques for the integration of dynamic seismic data into reservoir models, streamline-based techniques have been demonstrated as one of the more efficient approaches as a result of their analytical sensitivity formulations. Although streamline techniques have been used in the past to integrate time-lapse seismic attributes, the applications were limited to the simplified modeling scenarios of two-phase fluid flow and invariant streamline geometry throughout the production schedule. This research builds upon and advances existing approaches to streamline-based seismic data integration for the inclusion of both production and seismic data under varying field conditions. The proposed approach integrates data from reservoirs under active reservoir management and the corresponding simulation models can be constrained using highly detailed or realistic schedules. Fundamentally, a new derivation of seismic sensitivities is proposed that is able to represent a complex reservoir evolution between consecutive seismic surveys. The approach is further extended to manage compositional reservoir simulation with dissolution effects and gravity-convective-driven flows which, in particular, are typical of CO2 transport behavior following injection into deep saline aquifers. As a final component of this research, the benefits of dynamic data integration on the determination of swept and drained volumes by injection and production, respectively, are investigated. Several synthetic and field reservoir modeling scenarios are used for an extensive demonstration of the efficacy and practical feasibility of the proposed developments.

Rey Amaya, Alvaro

2011-08-01T23:59:59.000Z

413

Econometric Modelling of World Oil Supplies: Terminal Price and the Time to Depletion  

E-Print Network (OSTI)

This paper develops a novel approach by which to identify the price of oil at the time of depletion; the so-called "terminal price " of oil. It is shown that while the terminal price is independent of both GDP growth and the price elasticity of energy demand, it is dependent on the world real interest rate and the total life-time stock of oil resources, as well as on the marginal extraction and scarcity cost parameters. The theoretical predictions of this model are evaluated using data on the cost of extraction, cumulative production, and proven reserves. The predicted terminal prices seem sensible for a range of parameters and variables, as illustrated by the sensitivity analysis. Using the terminal price of oil, we calculate the time to depletion, and determine the extraction and price proles over the life-time of the resource. The extraction proles generated seem to be in line with the actual production and the predicted prices are generally in line with those currently observed.

Kamiar Mohaddes

2013-01-01T23:59:59.000Z

414

TIME-LAPSE SEISMIC MODELING & INVERSION OF CO2 SATURATION FOR SEQUESTRATION AND ENHANCED OIL RECOVERY  

SciTech Connect

Injection of carbon dioxide (CO2) into subsurface aquifers for geologic storage/sequestration, and into subsurface hydrocarbon reservoirs for enhanced oil recovery, has become an important topic to the nation because of growing concerns related to global warming and energy security. In this project we developed new ways to predict and quantify the effects of CO2 on seismic data recorded over porous reservoir/aquifer rock systems. This effort involved the research and development of new technology to: (1) Quantitatively model the rock physics effects of CO2 injection in porous saline and oil/brine reservoirs (both miscible and immiscible). (2) Quantitatively model the seismic response to CO2 injection (both miscible and immiscible) from well logs (1D). (3) Perform quantitative inversions of time-lapse 4D seismic data to estimate injected CO2 distributions within subsurface reservoirs and aquifers. This work has resulted in an improved ability to remotely monitor the injected CO2 for safe storage and enhanced hydrocarbon recovery, predict the effects of CO2 on time-lapse seismic data, and estimate injected CO2 saturation distributions in subsurface aquifers/reservoirs. We applied our inversion methodology to a 3D time-lapse seismic dataset from the Sleipner CO2 sequestration project, Norwegian North Sea. We measured changes in the seismic amplitude and traveltime at the top of the Sleipner sandstone reservoir and used these time-lapse seismic attributes in the inversion. Maps of CO2 thickness and its standard deviation were generated for the topmost layer. From this information, we estimated that 7.4% of the total CO2 injected over a five-year period had reached the top of the reservoir. This inversion approach could also be applied to the remaining levels within the anomalous zone to obtain an estimate of the total CO2 injected.

Mark A. Meadows

2006-03-31T23:59:59.000Z

415

A Time Dependent Leptonic Model for Microquasar Jets: Application to LSI 61 303  

E-Print Network (OSTI)

The Galactic high-mass X-ray binary and jet source (microquasar) LSI +61 303 has recently been detected at TeV gamma-ray energies by the MAGIC telescope. We have applied a time-dependent leptonic jet model to the broadband spectral energy distribution and suggested (though not unambiguously detected) orbital modulation of the very high energy gamma-ray emission of this source. Our model takes into account time dependent electron injection and acceleration, and the adiabatic and radiative cooling of non-thermal electrons. It includes synchrotron, synchrotron self-Compton and external inverse Compton (with seed photons from the companion star), as well as gamma-gamma absorption of gamma-rays by starlight photons. The model can successfully reproduce the available multiwavelength observational data. Our best fit to the SED indicates that a magnetic field of B_0 ~ 5 X 10^3 G at ~ 10^3 R_g is required, and electrons need to be accelerated out to TeV energies (gamma_2 = 10^6) with a nonthermal injection spectrum with a spectral index of q = 1.7, indicating the operation of acceleration mechanisms beyond the standard first-order Fermi mechanism at relativistic or non-relativistic shocks. The orbital modulation of the VHE gamma-ray emission can be explained solely by the geometrical effect of changes in the relative orientation of the stellar companion with respect to the compact object and jet as it impacts the position and depth of the gamma-gamma absorption trough. Such a scenario predicts a trend of spectral hardening during VHE gamma-ray low orbital phases.

Swati Gupta; Markus Boettcher

2006-06-23T23:59:59.000Z

416

Argonne CNM: Colloquium Series  

NLE Websites -- All DOE Office Websites (Extended Search)

Colloquium Series Colloquium Series The Center for Nanoscale Materials holds a regular biweekly colloquium on alternate Wednesday afternoons at 4:00 p.m. in Bldg. 440, Room A105/106. The goal of the series is to provide a forum for topical multidisciplinary talks in areas of interest to the CNM and also to offer a mechanism for fostering interactions with potential facility users. Refreshments will be served at 3:45. January 15, 2013 "Friction, Brownian Motion, and Energy Dissipation Mechanisms in Adsorbed Molecules and Molecularly Thin Films: Heating, Electrostatic and Magnetic Effects," by Jacquelin Krim, North Carolina State University, hosted by Diana Berman Abstract: In the study of friction at the nanoscale, phononic, electrostatic, conduction electron, and magnetic effects all contribute to the dissipation mechanisms. Electrostatic and magnetic contributions are increasingly alluded to in the current literature, but they remain poorly characterized. I will first overview the nature of these various contribution, and then report on our observations of magnetic and electrostatic contributions to friction for various systems in the presence and absence of external fields. I will also report on the use of a quartz crystal microbalance with a graphene/Ni(111) electrode to probe frictional heating effects in Kr monolayers sliding on the microbalance electrode in response to its oscillatory motion.

417

Bayesian Nonparametric Hidden Semi-Markov Models  

E-Print Network (OSTI)

There is much interest in the Hierarchical Dirichlet Process Hidden Markov Model (HDP-HMM) as a natural Bayesian nonparametric extension of the ubiquitous Hidden Markov Model for learning from sequential and time-series ...

Johnson, Matthew James

418

Flow Control of Real Time Multimedia Applications Using Model Predictive Control with a Feed Forward Term  

E-Print Network (OSTI)

Multimedia applications over the Internet are getting more and more popular. While non-real-time streaming services, such as YouTube and Megavideo, are attracting millions of visiting per day, real-time conferencing applications, of which some instances are Skype and Yahoo Voice Chat, provide an interesting experience of communication. Together, they make the fancy Internet world become more and more amusing. Undoubtedly, multimedia flows will eventually dominate the computer network in the future. As the population of multimedia flows increases gradually on the Internet, quality of their service (QoS) is more of a concern. At the moment, the Internet does not have any guarantee on the quality of multimedia services. To completely surpass this limitation, modifications to the network structure is a must. However, it will take years and billions of dollars in investment to achieve this goal. Meanwhile, it is essential to find alternative ways to improve the quality of multimedia services over the Internet. In the past few years, many endeavors have been carried on to solve the problem. One interesting approach focuses on the development of end-to-end congestion control strategies for UDP multimedia flows. Traditionally, packet losses and delays have been commonly used to develop many known control schemes. Each of them only characterizes some different aspects of network congestion; hence, they are not ideal as feedback signals alone. In this research, the flow accumulation is the signal used in feedback for flow control. It has the advantage of reflecting both packet losses and delays; therefore, it is a better choice. Using network simulations, the accumulations of real-time audio applications are collected to construct adaptive flow controllers. The reason for choosing these applications is that they introduce more control challenges than non-real-time services. One promising flow control strategy was proposed by Bhattacharya and it was based on Model Predictive Control (MPC). The controller was constructed from an ARX predictor. It was demonstrated that this control scheme delivers a good QoS while reducing bandwidth use in the controlled flows by 31 percent to 44 percent. However, the controller sometime shows erratic response and bandwidth usage jumps frequently between lowest and highest values. This is not desirable. For an ideal controller, the controlled bandwidth should vary near its mean. To eliminate the deficiency in the strategy proposed by Bhattacharya, it is proposed to introduce a feed forward term into the MPC formulation, in addition to the feedback terms. Simulations show that the modified MPC strategy maintains the benefits of the Bhattacharya strategy. Furthermore, it increases the probability of bandwidth savings from 58 percent for the case of Bhattacharya model to about 99 percent for this work.

Duong, Thien Chi

2010-12-01T23:59:59.000Z

419

Illustration of a New Test for Detecting a Shift in Mean in Precipitation Series  

Science Conference Proceedings (OSTI)

Maronna and Yohai (1978) have introduced a new test for detecting a shift in mean in an independent time series, based on a second correlated series. Unlike other procedures commonly applied to precipitation series, this test is statistically ...

Kenneth W. Potter

1981-09-01T23:59:59.000Z

420

Development of an Optimum Tracer Set for Apportioning Emissions of Individual Power Plants Using Highly Time-Resolved Measurements and Advanced Receptor Modeling  

SciTech Connect

In previous studies, 11 elements (Al, As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Se, and Zn) were determined in 30-minute aerosol samples collected with the University of Maryland Semicontinuous Elements in Aerosol Sampler (SEAS; Kidwell and Ondov, 2001, 2004; SEAS-II) in several locations in which air quality is influenced by emissions from coal- or oil-fired power plants. At this time resolution, plumes from stationary high temperature combustion sources are readily detected as large excursions in ambient concentrations of elements emitted by these sources (Pancras et al. ). Moreover, the time-series data contain intrinsic information on the lateral diffusion of the plume (e.g., {sigma}{sub y}), which Park et al. (2005 and 2006) have exploited in their Pseudo-Deterministic Receptor Model (PDRM), to calculate emission rates of SO{sub 2} and 11 elements (mentioned above) from four individual coal- and oil-fired power plants in the Tampa Bay area. In the current project, we proposed that the resolving power of source apportionment methods might be improved by expanding the set of maker species and that there exist some optimum set of marker species that could be used. The ultimate goal was to determine the utility of using additional elements to better identify and isolate contributions of individual power plants to ambient levels of PM and its constituents. And, having achieved better resolution, achieve, also, better emission rate estimates. In this study, we optimized sample preparation and instrumental protocols for simultaneous analysis of 28 elements in dilute slurry samples collected with the SEAS with a new state-of-the-art Thermo-Systems, Inc., X-series II, Inductively Coupled Plasma Mass Spectroscopy (ICP-MS), and reanalyzed the samples previously collected in Tampa during the modeling period studied by Park et al. (2005) in which emission rates from four coal- and oil-fired power plants affected air quality at the sampling site. In the original model, Park et al. (2005), included 6 sources. Herein, we reassessed the number of contributing sources in light of the new data. A comprehensive list of sources was prepared and both our Gaussian Plume model and PMF were used to identify and predict the relative strengths of source contributions at the receptor sites. Additionally, PDRM was modified to apply National Inventory Emissions, Toxic Release Inventory, and Chemical Mass Balance source profile data to further constrain solutions. Both the original Tampa data set (SO{sub 2} plus 11 elements) and the new expanded data set (SO{sub 2} plus 23 elements) were used to resolve the contributions of particle constituents and PM to sources using Positive Matrix Factorization (PMF) and PDRM.

John Ondov; Gregory Beachley

2007-07-05T23:59:59.000Z

Note: This page contains sample records for the topic "time series models" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Possibility of Skill Forecast Based on the Finite-Time Dominant Linear Solutions for a Primitive Equation Regional Forecast Model  

Science Conference Proceedings (OSTI)

The possibility of using forecast errors originating from the finite-time dominant linear modes for the prediction of forecast skill for a primitive equation regional forecast model is studied. This is similar to the method for skill prediction ...

Tomislava Vuki?evi?

1993-06-01T23:59:59.000Z

422

High-Order Generalized Lorenz N-Cycle Schemes for Semi-Lagrangian Models Employing Second Derivatives in Time  

Science Conference Proceedings (OSTI)

Having recently demonstrated that significant enhancement of forecast accuracy in a semi-Lagrangian model results from the application of high-order time integration methods to the second-derivative form of the equations governing the ...

R. J. Purser; L. M. Leslie

1997-06-01T23:59:59.000Z

423

Value of Real-Time Vegetation Fraction to Forecasts of Severe Convection in High-Resolution Models  

Science Conference Proceedings (OSTI)

Near-real-time values of vegetation fraction are incorporated into a 2-km nested version of the Advanced Research Weather Research and Forecasting (ARW) model and compared to forecasts from a control run that uses climatological values of ...

Kenneth A. James; David J. Stensrud; Nusrat Yussouf

2009-02-01T23:59:59.000Z

424

Hindcasting Ocean Climate Variability Using Time-Dependent Surface Data to Drive a Model: An Idealized Study  

Science Conference Proceedings (OSTI)

This paper investigates the hindcasting of interdecadal climate events using an ocean circulation model driven by different combinations of time-varying surface flux, sea surface temperature (SST), and sea surface salinity (SSS) data. Data are ...

Richard J. Greatbatch; Guoqing Li; Sheng Zhang

1995-11-01T23:59:59.000Z

425

Crude Oil Price Forecasting: A Transfer Learning Based Analog Complexing Model  

Science Conference Proceedings (OSTI)

Most of the existing models for oil price forecasting only use the data in the forecasted time series itself. This study proposes a transfer learning based analog complexing model (TLAC). It first transfers some related time series in source domain to ... Keywords: transfer learning method, analog complexing model, genetic algorithm, crude oil price forecasting

Jin Xiao; Changzheng He; Shouyang Wang

2012-08-01T23:59:59.000Z

426

Reconciling Simulated Moisture Fluxes Resulting from Alternate Hydrologic Model Time Steps and Energy Budget Closure Assumptions  

Science Conference Proceedings (OSTI)

Hydrological model predictions are sensitive to model forcings, input parameters, and the parameterizations of physical processes. Analyses performed for the Variable Infiltration Capacity model show that the resulting moisture fluxes are ...

Ingjerd Haddeland; Dennis P. Lettenmaier; Thomas Skaugen

2006-06-01T23:59:59.000Z

427

Development of Fast-Time Simulation Techniques to Model Safety Issues in the National Airspace System  

E-Print Network (OSTI)

Development of an agent-based simulation model of airDevelopment of an agent-based simulation model of airDevelopment of an agent-based simulation model of air

2002-01-01T23:59:59.000Z

428

Evaluating the Quality of Mobile Medical Speech Translators Based on ISO/IEC 9126 Series: Definition, Weighted Quality Model and Metrics  

Science Conference Proceedings (OSTI)

Medical translation systems present an intriguing research area as language barriers can become life-threatening when health issues come into place. There is however a lack of common evaluation methodologies, making the fair comparison of such systems ... Keywords: Evaluation, International Standardization Organization ISO 9126, Medical Translation, Mobile, Quality Model, Speech-To-Speech Translation

Nikos Tsourakis, Paula Estrella

2013-04-01T23:59:59.000Z

429

A Comparison of Baroclinic Instability with the Time Variations of Kinetic Energy in a General Circulation Model  

Science Conference Proceedings (OSTI)

The flow generated by a general circulation model is zonally averaged at 1-day intervals, and, for each of the axisymmetric flows obtained, the linear growth-rate spectrum for baroclinic waves is computed using a linear model. The time sequence ...

Robert Walko; Robert Gall

1980-08-01T23:59:59.000Z

430

The Use of a Two-Dimensional, Time-Dependent Cloud Model to Predict Convective and Stratiform Clouds and Precipitation  

Science Conference Proceedings (OSTI)

A two-dimensional, time-dependent cloud model has been used in two field projects to forecast the convective development during the day from the morning sounding. In effect, the cloud model gives a dynamic analysis of the sounding as affected by ...

Fred J. Kopp; Harold D. Orville

1994-03-01T23:59:59.000Z

431

Location Analysis Model for Belgian Intermodal Terminals: Importance of the value of time in the intermodal transport chain  

Science Conference Proceedings (OSTI)

Intermodal transport, the combination and integration of several transport modes, with the use of loading units, is in most cases more environmentally friendly than unimodal road transport for the carriage of goods. The LAMBIT-model (Location Analysis ... Keywords: Empty returns, GIS network model, Intermodal transport, Value of time

Ethem Pekin; Cathy Macharis; Dries Meers; Piet Rietveld

2013-02-01T23:59:59.000Z

432

Physics for Everyone Lecture Series  

NLE Websites -- All DOE Office Websites (Extended Search)

Physics for Everyone lecture series A non-technical lecture series about Fermilab science and culture Talks take place on Wednesdays each month from 12:30-1:30 p.m. in the...

433

Brookhaven Lecture Series | Home  

NLE Websites -- All DOE Office Websites (Extended Search)

Next Brookhaven Lecture Next Brookhaven Lecture JAN 22 Wednesday Brookhaven Lecture "491st Brookhaven Lecture: Juergen Thieme of Photon Sciences Directorate" Presented by Juergen Thieme, Brookhaven Lab's Photon Sciences Directorate 4 pm, Berkner Hall Auditorium Wednesday, January 22, 2014, 4:00 pm Hosted by: Allen Orville Refreshments will be served before and after the lecture. Brookhaven Lectures are free and open to the Public. Visitors to the Laboratory age 16 and older must bring photo ID. About the Brookhaven Lecture Series Gertrude Scharff-Goldhaber Gertrude Scharff-Goldhaber The Brookhaven Lectures, held by and for the Brookhaven staff, are meant to provide an intellectual meeting ground for all scientists of the Laboratory. In this role they serve a double purpose: they are to acquaint

434

3800 Green Series Cost Elements  

Energy.gov (U.S. Department of Energy (DOE))

Stoller - Legacy ManagementSustainable Acquisition (formerly EPP) Program 3800 Series Cost Elements01/30/2012 (Rev. 4)

435

Generalized series of Bessel functions  

Science Conference Proceedings (OSTI)

Known series of Bessel functions, currently available in handbooks, and many of Neumann type, are generalized to arbitrary order. The underlying result is a Poisson formula due to Titchmarsh. This formula gives rise to a Neumann series involving modified ... Keywords: Bessel functions, Neumann series

A. Al-Jarrah; K. M. Dempsey; M. L. Glasser

2002-06-01T23:59:59.000Z

436

Book Series ontos mathematical logic  

E-Print Network (OSTI)

Book Series ontos mathematical logic Information for Authors Edited by Wolfram Pohlers (Münster sheet. The books of this new series will be published in hardcover (except of student handbooks) and will be available for at least ten years. The books of this series will be distributed in Middle Europe by ontos

Schindler, Ralf

437

J. Plasma Fusion Res. SERIES, Vol. 10 (2013) Simulating Tritium Retention in Tungsten with a Multiple Trap Model in the TMAP Code a  

E-Print Network (OSTI)

Accurately predicting the quantity of tritium retained in plasma facing components is a key safety issue for licensing future fusion power reactors. Retention of tritium in the lattice damage caused when high energy neutrons collide with atoms in the structural material of the reactors plasma facing components (PFCs) is an area of ongoing experimental research at the Idaho National Laboratory (INL) under the US/Japan TITAN collaboration. Recent experiments with the Tritium Plasma Experiment (TPE), located in the INLs Safety and Tritium Applied Research (STAR) facility, demonstrate that this damage can only be simulated by computer codes like the Tritium Migration Analysis Program (TMAP) if one assumes that the lattice damage produced by these neutrons results in multiple types of hydrogen traps (energy wells) within the material, each possessing a different trap energy and density. Previous attempts to simulate the quantity of deuterium released from neutron irradiated TPE tungsten targets indicated that at least six different traps are required by TMAP to model this release. In this paper we describe a recent extension of the TMAP trap site model to include as many traps as required by the user to simulate retention of tritium in neutron damaged tungsten. This model has been applied to data obtained for tungsten irradiated to a damage level of 0.025 dpa in the High Flux Isotope Reactor (HFIR) at the Oak Ridge National Laboratory (ORNL) after exposure to a plasma in TPE.

Brad J. Merrill; Masashi Shimada; Paul W. Humrickhouse

2012-01-01T23:59:59.000Z

438

Analyzing the Impacts of Frequency and Severity of Forest Fire on the Recovery of Disturbed Forest using Landsat Time Series and EO-1 Hyperion in the Southern Brazilian Amazon  

Science Conference Proceedings (OSTI)

Estimation of fire impacts and forest recovery using remote sensing is difficult because of the heterogeneity of fire history (frequency, severity, and time since last fire) across burned forest landscapes. The authors analyzed impacts of fire ...

Izaya Numata; Mark A. Cochrane; Lnio S. Galvo

2011-05-01T23:59:59.000Z

439

A novel HMM-based clustering algorithm for the analysis of gene expression time-course data  

Science Conference Proceedings (OSTI)

A novel hidden Markov model (HMM) and clustering algorithm for the analysis of gene expression time-course data is proposed. The proposed model, called the profile-HMM, is specifically designed to explicitly take into account the dynamic nature of temporal ... Keywords: Clustering, Gene expression time-course data, Hidden Markov models, Temporal dependences, Time-series analysis

Yujing Zeng; Javier Garcia-Frias

2006-05-01T23:59:59.000Z

440

A metric time-point and duration-based temporal model  

Science Conference Proceedings (OSTI)

Constraint-based formalisms are a useful and common way to deal with temporal reasoning tasks. Assertions represent temporal constraints between temporal objects, time-points or intervals: Metric temporal constraints between time points permit us to ...

Federico A. Barber

1993-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "time series models" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Incorporating attitudes in airline itinerary choice : modeling the impact of elapsed time  

E-Print Network (OSTI)

Network airlines traditionally try to minimize the elapsed time of their passengers in connecting travel, based on the assumption that longer elapsed times would make their itinerary less competitive and thus reduce their ...

Theis, Georg Wilhelm

2011-01-01T23:59:59.000Z

442

Modeling the Variability of Drop Size Distributions in Space and Time  

Science Conference Proceedings (OSTI)

The information on the time variability of drop size distributions (DSDs) as seen by a disdrometer is used to illustrate the structure of uncertainty in radar estimates of precipitation. Based on this, a method to generate the spacetime ...

Gyu Won Lee; Alan W. Seed; Isztar Zawadzki

2007-06-01T23:59:59.000Z

443

Comparative review of the Time-stepped Energy System Optimization Model (TESOM) and the IEA Market Allocation Model (MARKAL)  

SciTech Connect

The two principal energy system models used in the National Center for Analysis of Energy Systems at Brookhaven National Laboratory are described and their important differences are contrasted.

Kydes, A.S.

1980-04-01T23:59:59.000Z

444

Empirical Models of the Eddy Heat Flux and Vertical Shear on Short Time Scales  

Science Conference Proceedings (OSTI)

The relationship between the eddy heat flux and vertical shear in the extratropical atmosphere is studied by developing various linear stochastic models fitted to the observed January and July Northern Hemispheric data. Models are univariate or ...

Steven J. Ghan

1984-02-01T23:59:59.000Z

445

On the Modeling Timing Behavior of the System with UML(VR)  

Science Conference Proceedings (OSTI)

UML notation is assumed to be independent from any software modeling methodology. The existing methodologies support the creation of the final system model, but they do not care about the formal documentation of the reasoning process; the associations ...

Leszek Kotulski; Dariusz Dymek

2008-06-01T23:59:59.000Z

446

Scalability of Parallel Gridpoint Limited-Area Atmospheric Models. Part I: Explicit Time-Integration Schemes  

Science Conference Proceedings (OSTI)

A performance model of parallel domain decompositions for explicit gridpoint limited-area atmospheric models is developed, and the parallel scalability is analyzed. Given a set of reasonable assumptions, a two-dimensional horizontal decomposition ...

Roar Sklin

1997-06-01T23:59:59.000Z

447

Applying the multivariate time-rescaling theorem to neural population models  

E-Print Network (OSTI)

Statistical models of neural activity are integral to modern neuroscience. Recently interest has grown in modeling the spiking activity of populations of simultaneously recorded neurons to study the effects of correlations ...

Gerhard, Felipe

448

Time Step Sensitivity of Nonlinear Atmospheric Models: Numerical Convergence, Truncation Error Growth, and Ensemble Design  

Science Conference Proceedings (OSTI)

Computational models based on discrete dynamical equations are a successful way of approaching the problem of predicting or forecasting the future evolution of dynamical systems. For linear and mildly nonlinear models, the solutions of the ...

Joo Teixeira; Carolyn A. Reynolds; Kevin Judd

2007-01-01T23:59:59.000Z

449

Development of Fast-Time Simulation Techniques to Model Safety Issues in the National Airspace System  

E-Print Network (OSTI)

Fundamental design limitations in MIDAS limit the scalability and practicality of MIDAS as a tool to model human performanceFundamental design limitations in MIDAS limit the scalability and practicality of MIDAS as a tool to model human performance

2002-01-01T23:59:59.000Z

450

Testing the Annular Mode Autocorrelation Time Scale in Simple Atmospheric General Circulation Models  

Science Conference Proceedings (OSTI)

A new diagnostic for measuring the ability of atmospheric models to reproduce realistic low-frequency variability is introduced in the context of Held and Suarezs 1994 proposal for comparing the dynamics of different general circulation models. ...

Edwin P. Gerber; Sergey Voronin; Lorenzo M. Polvani

2008-04-01T23:59:59.000Z

451

Supersymmetry and Gauge Invariance Constraints in a U(1)$\\times $U(1)$^{\\prime }$-Higgs Superconducting Cosmic String Model  

E-Print Network (OSTI)

A supersymmetric extension of the $U(1)\\times U(1)^{\\prime }$-Higgs bosonic superconducting cosmic string model is considered,and the constraints imposed upon such a model due to renormalizability, supersymmetry, and gauge invariance are examined. For a simple model with a single $U(1)$ chiral superfield and a single $% U(1)^{\\prime }$ chiral superfield, the Witten mechanism for bosonic superconductivity (giving rise to long range gauge fields outside of the string) does not exist. The simplest model that can accommodate the requisite interactions requires five chiral supermultiplets. This superconducting cosmic string solution is investigated.

J. R. Morris

1995-11-10T23:59:59.000Z

452

On Optimal Prediction of Atmospheric Ekman Layer Fluctuations over Short Lead Times  

Science Conference Proceedings (OSTI)

Wind and temperature time series, sampled at 10 min intervals 250 and 600 m above the ground, are analyzed. For horizontal wind components and temperature forecasting, autoregressive integrated models of the type (p, 1, 0); p ? 4 provide the best ...

Karl J. Eidsvik

1981-12-01T23:59:59.000Z

453

Multi-mutational model for cancer based on age-time patterns of radiation effects: 2. Biological aspects  

SciTech Connect

Biological properties of relevance when modeling cancers induced in the atom bomb survivors include the wide distribution of the induced cancers across all organs, their biological indistinguishability from background cancers, their rates being proportional to background cancer rates, their rates steadily increasing over at least 50 years as the survivors age, and their radiation dose response being linear. We have successfully described this array of properties with a modified Armitage-Doll model using 5 to 6 somatic mutations, no intermediate growth, and the dose-related replacement of any one of these time-driven mutations by a radiation-induced mutation. Such a model is contrasted to prevailing models that use fewer mutations combined with intervening growth. While the rationale and effectiveness of our model is compelling for carcinogenesis in the atom bomb survivors, the lack of a promotional component may limit the generality of the model for other types of human carcinogenesis.

Mendelsohn, M.L.; Pierce, P.A.

1997-09-04T23:59:59.000Z

454

Comment on "Time Step Sensitivity of Nonlinear Atmospheric Models: Numerical Convergence, Truncation Error Growth, and Ensemble Design" Teixeira et al. (2007)  

E-Print Network (OSTI)

Comment on "Time Step Sensitivity of Nonlinear Atmospheric Models: Numerical Convergence, Truncation Error Growth, and Ensemble Design" Teixeira et al.

Lun-Shin Yao; Dan Hughes

2007-04-26T23:59:59.000Z

455

TIME-LAPSE MODELING AND INVERSION OF CO{sub 2} SATURATION FOR SEQUESTRATION AND ENHANCED OIL RECOVERY  

SciTech Connect

In the second quarter of this DOE NETL project, we have continued Phase I and Phase II activities for researching and developing new technology to quantitatively model the rock physics effects of CO{sub 2}-oil-water systems. These activities included completing a literature search of currently available equation-of-state methods, initiating work in molecular dynamics modeling, and building a prototype seismic modeling code for predicting time-lapse CO{sub 2} changes in well-log models. We have also received permission to use the Sleipner time-lapse CO{sub 2} data set from the North Sea for the current NETL project, and have issued a formal request for the data.

Mark A. Meadows

2004-05-10T23:59:59.000Z

456

A study of detonation timing and fragmentation using 3-D finite element techniques and a damage constitutive model  

SciTech Connect

The transient dynamics finite element computer program, PRONTO-3D, has been used in conjunction with a damage constitutive model to study the influence of detonation timing on rock fragmentation during blasting. The primary motivation of this study is to investigate the effectiveness of precise detonators in improving fragmentation. PRONTO-3D simulations show that a delay time of 0.0 sec between adjacent blastholes results in significantly more fragmentation than a 0.5 ms delay.

Preece, D.S.; Thorne, B.J.

1996-03-01T23:59:59.000Z

457

Machining force regression models and real time control when turning MET 4 metallized coating  

Science Conference Proceedings (OSTI)

Due to their wide range of application, metallized coatings are widely used in industry, both for wear resistance or corrosion protection. In order to obtain the required geometric precision, machining these coatings is many times required. As their ... Keywords: control system, experiments design, force, metallized coating, real time, regression, turning

Mihaiela Iliescu; Luigi Vl?d?reanu; Marius Soceanu

2011-07-01T23:59:59.000Z

458

Jefferson Lab Science Series - Holograms  

NLE Websites -- All DOE Office Websites (Extended Search)

Clocks and Timekeeping Previous Video (Clocks and Timekeeping) Science Series Video Archive Next Video (Which Way is Up?) Which Way is Up? Holograms Mr. Paul Christie - Liti...

459

A California Statewide Three-Dimensional Seismic Velocity Model from Both Absolute and Differential Times  

E-Print Network (OSTI)

A California Statewide Three-Dimensional Seismic Velocity Model from Both Absolute and Differential of the California crust and uppermost mantle using a regional-scale double-difference tomography algorithm. We begin using S picks from both the Southern California Seismic Network and USArray, assuming a starting model

Shearer, Peter

460

Estimating joinpoints in continuous time scale for multiple change-point models  

Science Conference Proceedings (OSTI)

Joinpoint models have been applied to the cancer incidence and mortality data with continuous change points. The current estimation method [Lerman, P.M., 1980. Fitting segmented regression models by grid search. Appl. Statist. 29, 77-84] assumes that ... Keywords: Cancer incidence and mortality, Constrained least square, Joinpoint regression, SEER

Binbing Yu; Michael J. Barrett; Hyune-Ju Kim; Eric J. Feuer

2007-02-01T23:59:59.000Z

Note: This page contains sample records for the topic "time series models" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

Time domain 3D finite element modelling of train-induced vibration at high speed  

Science Conference Proceedings (OSTI)

The purpose of this paper is to investigate a 3D finite element (FE) coupled train-track model for the numerical modelling of the ground induced vibration due to the passage of a single high speed train locomotive. The track components such as the sleepers, ... Keywords: Finite elements, Ground vibration, High-speed, Mach cone, Railways

A. El Kacimi; P. K. Woodward; O. Laghrouche; G. Medero

2013-03-01T23:59:59.000Z

462

Development of Fast-Time Simulation Techniques to Model Safety Issues in the National Airspace System  

E-Print Network (OSTI)

NASA nm PIREP RAM RFS RTI SJSU SOM UCB Aviation PerformanceHLA interface standards and RTI software. Demonstration ofits Run-Time Interface (RTI) appears to be a very efficient

2002-01-01T23:59:59.000Z

463

Real-Time Forecasting of the Western Australian Summertime Trough: Evaluation of a New Regional Model  

Science Conference Proceedings (OSTI)

The real-time prediction of the location, strength, and structure of the summertime heat trough is a major forecasting problem over Western Australia. Maximum temperatures, wind strength and direction along the west coast, low-level coastal cloud,...

Lance M. Leslie; Terry C. L. Skinner

1994-09-01T23:59:59.000Z

464

Real-time Expression Cloning using Appearance Models Barry-John Theobald  

E-Print Network (OSTI)

expressions to be transferred and rendered in real-time. 3) The mapped expression can be constrained to have of a complex interaction between various anatomical layers, which include bone, muscle, sub- cutaneous fat

Theobald, Barry-John

465

Modeling and Forecasting the Southern Oscillation: A Time-Domain Approach  

Science Conference Proceedings (OSTI)

An index consisting of the difference of normalized sea level pressure departures between Tahiti and Darwin is used to represent the Southern Oscillation (SO) fluctuations. Using a time-domain approach, autoregressive-moving average (ARMA) ...

Pao-Shin Chu; Richard W. Katz

1985-11-01T23:59:59.000Z

466

Photon-limited time of flight depth acquisition : new parametric model and its analysis  

E-Print Network (OSTI)

As 3-D imaging systems become more popular, the depth estimation which is their core component should be made as accurate as possible at low power levels. In this thesis, we consider the time of flight depth acquisition ...

Montazerhodjat, Vahid

2013-01-01T23:59:59.000Z

467

Atmospheric Release Advisory Capability: Real-Time Modeling of Airborne Hazardous Materials  

Science Conference Proceedings (OSTI)

The Atmospheric Release Advisory Capability (ARAC) at Lawrence Livermore National Laboratory is a centralized federal project for assessing atmospheric releases of hazardous materials in real time. Since ARAC began making assessments in 1974, the ...

Thomas J. Sullivan; James S. Ellis; Connee S. Foster; Kevin T. Foster; Ronald L. Baskett; John S. Nasstrom; Walter W. Schalk III

1993-12-01T23:59:59.000Z

468

Jet fuel ignition delay times: Shock tube experiments over wide conditions and surrogate model predictions  

Science Conference Proceedings (OSTI)

Ignition delay times were measured for gas-phase jet fuel (Jet-A and JP-8) in air behind reflected shock waves in a heated high-pressure shock tube. Initial reflected shock conditions were as follows: temperatures of 715-1229 K, pressures of 17-51 atm, equivalence ratios of 0.5 and 1, and oxygen concentrations of 10 and 21% in synthetic air. Ignition delay times were measured using sidewall pressure and OH* emission at 306 nm. Longer ignition delay times at low temperatures (715-850 K) were accessed by utilizing driver-gas tailoring methods. Also presented is a review of previous ignition delay time measurements of kerosene-based fuels and recent work on surrogate fuel and kinetic mechanism development. To our knowledge, we report the first gas-phase shock tube ignition delay time data for JP-8, and our measurements for Jet-A are for a broader range of conditions than previously available. Our results have very low scatter and are in excellent agreement with the limited previous shock tube data for Jet-A. Although JP-8 and Jet-A have slightly different compositions, their ignition delay times are very similar. A simple 1/P dependence was found for ignition delay times from 874 to 1220 K for the pressure range studied for both fuels. Ignition delay time variations with equivalence ratio and oxygen concentration were also investigated. The new experimental results were compared with predictions of several kinetic mechanisms, using different jet fuel surrogate mixtures. (author)

Vasu, Subith S.; Davidson, David F.; Hanson, Ronald K. [Mechanical Engineering Department, Stanford University, Stanford, CA 94305 (United States)

2008-01-15T23:59:59.000Z

469

The Use of TVD Limiters for Forward-in-Time Upstream-Biased Advection Schemes in Ocean Modeling  

Science Conference Proceedings (OSTI)

This paper explores the use of the constant grid flux form forward-in-time upstream-biased advection schemes for the advection of temperature and salinity in ocean modeling. The constant grid flux form schemes are shown to be an improvement over ...

Julie Pietrzak

1998-03-01T23:59:59.000Z

470

Using support vector regression to model the correlation between the clinical metastases time and gene expression profile for breast cancer  

Science Conference Proceedings (OSTI)

Objective: Recently, the microarray analysis has been an important tool used for studying the cancer type, biological mechanism, and diagnostic biomarkers. There are several machine-learning methods being used to construct the prognostic model based ... Keywords: Breast cancer, Feature selection, Metastases time, Microarray, Support vector regression

Shih-Hau Chiu; Chien-Chi Chen; Thy-Hou Lin

2008-11-01T23:59:59.000Z

471

Time-Mean Response over the Tropical Pacific to Increased C02 in a Coupled Ocean-Atmosphere Model  

Science Conference Proceedings (OSTI)

The time-mean response over the tropical Pacific region to a quadrupling Of CO2 is investigated using a global coupled ocean-atmosphere general circulation model. Tropical Pacific sea surface temperatures (SSTs) rise by about 45C. The zonal ...

Thomas R. Knutson; Syukuro Manabe

1995-09-01T23:59:59.000Z

472

Skill of Real-Time Seasonal ENSO Model Predictions during 200211: Is Our Capability Increasing?  

Science Conference Proceedings (OSTI)

Real-time model predictions of ENSO conditions during the 200211 period are evaluated and compared to skill levels documented in studies of the 1990s. ENSO conditions are represented by the Nio- 3.4 SST index in the east-central tropical Pacific. The ...

Anthony G. Barnston; Michael K. Tippett; Michelle L. L'Heureux; Shuhua Li; David G. DeWitt

2012-05-01T23:59:59.000Z

473

Sub-national TIMES model for analyzing regional future use of Biomass and Biofuels in France and  

E-Print Network (OSTI)

1 Sub-national TIMES model for analyzing regional future use of Biomass and Biofuels in France Introduction Renewable energy sources such as biomass and biofuels are increasingly being seen as important of biofuels on the final consumption of energy in transport should be 10%. The long-term target is to reduce

Paris-Sud XI, Université de

474

Seasonal Precipitation Forecasting with a 67 Month Lead Time in the Pacific Northwest Using an Information Theoretic Model  

Science Conference Proceedings (OSTI)

An entropy minimax analysis for the forecast of seasonal precipitation with a 67 month lead time was performed for two regions in the Pacific Northwest. A model for the forecast of winter precipitation in the Willamette Valley, Oregon was ...

R. A. Christensen; R. F. Eilbert

1985-04-01T23:59:59.000Z

475

Space-Time Spectral Structure of a GLAS General Circulation Model and a Comparison with Observations  

Science Conference Proceedings (OSTI)

The wavenumber-frequency spectra of geopotential height have been computed from a winter simulation of a GLAS general circulation model, and are compared to the spectra obtained from 15 winters of observed analyses. The variances in several ...

David M. Straus; J. Shukla

1981-05-01T23:59:59.000Z

476

Backward-Time Lagrangian Stochastic Dispersion Models and Their Application to Estimate Gaseous Emissions  

Science Conference Proceedings (OSTI)

Backward Lagrangian stochastic models calculate an ensemble of fluid element (particle) trajectories that are distinguished by each passing through an observation point. As shown, they can be faster and more flexible in calculating short-range ...

Thomas K. Flesch; John D. Wilson; Eugene Yee

1995-06-01T23:59:59.000Z

477

Characteristics of the RAW Filtered Leapfrog Time-stepping Scheme in the Ocean General Circulation Model  

Science Conference Proceedings (OSTI)

The Robert-Asselin-Williams (RAW) filtered leapfrog scheme is implemented and tested in the Taiwan multi-scale community ocean model (TIMCOM). The characteristics of the RAW filter are carefully examined through two benchmark tests (the classical ...

Chih-Chieh Young; Yu-Chiao Liang; Yu-Heng Tseng; Chun-Hoe Chow

478

Modeling and centralization of strategic inventory for repairable and long lead-time spare parts  

E-Print Network (OSTI)

This thesis develops an optimal inventory model for repairable and long leadtime spare parts for an Engine overhaul business. In addition, it presents a business case for centralization of inventory. Pratt & Whitney purchased ...

Duncan, Tyeliah Elaine

2011-01-01T23:59:59.000Z

479

Marcellus Shale Educational Webinar Series  

E-Print Network (OSTI)

#12;Marcellus Shale Litigation and Legislation December 17, 2009 7 . Pennsylvania Oil and Gas Law1 Marcellus Shale Educational Webinar Series October 2009 - March 2010 Penn State Cooperative Extension #12;2 Marcellus Shale Webinar Series Planning Committee · Members ­ Mark Douglass, Jefferson

Boyer, Elizabeth W.

480

Systematic time-based study for quantifying the uncertainty of uncalibrated models in building energy simulations  

E-Print Network (OSTI)

This thesis documents the usefulness and accuracy of uncalibrated simulations to determine for what end-uses these simulations should be used. The study was divided into three segments 1)comparison of the accuracy of two simulation models, massless and advanced, against measured data 2) comparison of the results from two simulations models, simplistic and massless, to determine the sensitivity of envelope shape and details for two weather conditions 3) identification of the parameters that have a significant impact on the simulation output. Five buildings were selected as the test sample. Four of the buildings were multi story commercial buildings. The fifth was a single-family residential house. For the first segment of the study two simulation models were created for all the buildings; the massless model with emphasis on the envelope using massless construction and typical values for system parameters and the advanced model with the inclusion of thermal mass and extensive as-built details of the systems. For the second part of the research the simplistic model was created having a single floor one-zone with glazing and conditioned areas equivalent to the massless model. The sensitivity analysis was done using the massless model and selected variables from the loads and systems as sensitivity parameters. By following the procedure mentioned, it was found that uncalibrated simulation models do not depict the real operating conditions of a building. For some cases the simulated values are higher than the measured data while for others they are significantly lower. The CV (RMSE) between the measured and simulated values ranges from 30 to 150%. From the comparison of the simplistic and massless model, it was concluded that the outer envelope shape and details have an impact on the heating and cooling energy use irrespective of the weather conditions. For internally load dominated buildings this impact is more on the heating loads than on the cooling loads. The conclusions from the sensitivity analysis were that outside air fraction and the total supply air have the most significant impact on the simulation output while thermal mass has a small impact.

Ahmad, Mushtaq

2003-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "time series models" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


481

Time-domain Simulation of Multibody Floating Systems based on State-space Modeling Technology  

E-Print Network (OSTI)

A numerical scheme to simulate time-domain motion responses of multibody floating systems has been successfully proposed. This scheme is integrated into a time-domain simulation tool, with fully coupled hydrodynamic coefficients obtained from the hydrodynamic software - WAMIT which solves the Boundary Value Problem (BVP). The equations of motion are transformed into standard state-space format, using the constant coefficient approximation and the impulse response function method. Thus the Ordinary Differential Equation (ODE) solvers in MATLAB can be directly employed. The time-domain responses of a single spar at sea are initially obtained. The optimal Linear Quadratic Regulator (LQR) controller is further applied to this single spar, by assuming that the Dynamic Positioning (DP) system can provide the optimized thruster forces. Various factors that affect the controlling efficiency, e.g., the time steps ?? and ?t, the weighting factors(Q,R), are further investigated in detail. Next, a two-body floating system is studied. The response amplitude operators (RAOs) of each body are calculated and compared with the single body case. Then the effects of the body-to-body interaction coefficients on the time-domain responses are further investigated. Moreover, the mean drift force is incorporated in the DP system to further mitigate the motion responses of each body. Finally, this tool is extended to a three-body floating system, with the relative motions between them derived.

Yu, Xiaochuan

2011-08-01T23:59:59.000Z

482

Testing Climate Models Using Thermal Infrared Spectra  

Science Conference Proceedings (OSTI)

An approach to test climate models with observations is presented. In this approach, it is possible to directly observe the longwave feedbacks of the climate system in time series of annual average outgoing longwave spectra. Tropospheric ...

Stephen Leroy; James Anderson; John Dykema; Richard Goody

2008-05-01T23:59:59.000Z

483

State-Space Modeling for Atmospheric Pollution  

Science Conference Proceedings (OSTI)

Two different aspect concerning the state-space modeling for atmospheric pollution are dealt with separately in this paper: (i) the treatment of the advection-diffusion equation and (ii) the use of time series analysis.

E. Hernndez; F. Martn; F. Valero

1991-06-01T23:59:59.000Z

484

Time-Varying PLC Network Modeling with Wavelet MDFB and Weighted OFDM Precoders  

Science Conference Proceedings (OSTI)

The paper addresses a problem of designing a simple, efficient power line network simulator embedded with two types of multirate filter bank precoders, weighted orthogonal frequency division multiplexing (OFDM) and wavelet-based maximally decimated filter ... Keywords: Power line communications (PLC), Weighted OFDM, Wavelet-based MDFB, Time-varying block transmission, Interblock interference (IBI)

Tae-Eung Sung

2009-07-01T23:59:59.000Z

485

Modelling of time related drying changes on matte coated paper with artificial neural networks  

Science Conference Proceedings (OSTI)

In this study, the determinability of time related colour changes in prints made using ink that dries on matte coated paper with the offset printing technique and infrared method, has been investigated with artifical neural networks after analysis of ... Keywords: Artificial neural networks, Colour changes, Offset printing

Trkn ?ahnba?kan; Erdo?an Kse

2010-04-01T23:59:59.000Z

486

Transit Timing Observations from Kepler: IV. Confirmation of 4 Multiple Planet Systems by Simple Physical Models  

SciTech Connect

Eighty planetary systems of two or more planets are known to orbit stars other than the Sun. For most, the data can be sufficiently explained by non-interacting Keplerian orbits, so the dynamical interactions of these systems have not been observed. Here we present 4 sets of lightcurves from the Kepler spacecraft, which each show multiple planets transiting the same star. Departure of the timing of these transits from strict periodicity indicates the planets are perturbing each other: the observed timing variations match the forcing frequency of the other planet. This confirms that these objects are in the same system. Next we limit their masses to the planetary regime by requiring the system remain stable for astronomical timescales. Finally, we report dynamical fits to the transit times, yielding possible values for the planets masses and eccentricities. As the timespan of timing data increases, dynamical fits may allow detailed constraints on the systems architectures, even in cases for which high-precision Doppler follow-up is impractical.

Fabrycky, Daniel C.; /UC, Santa Cruz; Ford, Eric B.; /Florida U.; Steffen, Jason H.; /Fermilab; Rowe, Jason F.; /SETI Inst., Mtn. View /NASA, Ames; Carter, Joshua A.; /Harvard-Smithsonian Ctr. Astrophys.; Moorhead, Althea V.; /Florida U.; Batalha, Natalie M.; /San Jose State U.; Borucki, William J.; /NASA, Ames; Bryson, Steve; /NASA, Ames; Buchhave, Lars A.; /Bohr Inst. /Copenhagen U.; Christiansen, Jessie L.; /SETI Inst., Mtn. View /NASA, Ames /Caltech

2012-01-01T23:59:59.000Z

487

Modeling an Electronic Throttle Controller using the Timed Abstract State Machine Language and Toolset  

E-Print Network (OSTI)

A key challenge in the design and analysis of real-time systems is the integration of functional and non-functional properties into a single specification. In this paper, we present an integrated toolset based on the TASM language. The toolset is used to specify and analyze reactive embedded real-time systems. The toolset implements the features of the Timed Abstract State Machine (TASM) language, a novel specification language. The non-functional properties that can be expressed in the language include timing behavior and resource consumption. The toolset enables the creation of executable specifications with well-defined execution semantics, abstraction mechanisms, and composition semantics. The toolset includes facilities for editing, analyzing, and simulating TASM specifications. The features of the toolset are demonstrated using an Electronic Throttle Controller (ETC) from a major automotive vendor. The TASM toolset is used to analyze the mode switching logic of the ETC. The ETC is used to calculate fuel injection and air intake to optimize fuel consumption. The TASM toolset is used to analyze the resource consumption resulting from the mode switching logic, and to verify the completeness and consistency of the specification.

Martin Ouimet; Guillaume Berteau; Kristina Lundqvist

2006-01-01T23:59:59.000Z

488

Accumulation of Biomass and Mineral Elements with Calendar Time by Corn: Application of the Expanded Growth Model  

E-Print Network (OSTI)

The expanded growth model is developed to describe accumulation of plant biomass (Mg ha 21) and mineral elements (kg ha 21) in with calendar time (wk). Accumulation of plant biomass with calendar time occurs as a result of photosynthesis for green land-based plants. A corresponding accumulation of mineral elements such as nitrogen, phosphorus, and potassium occurs from the soil through plant roots. In this analysis, the expanded growth model is tested against high quality, published data on corn (Zea mays L.) growth. Data from a field study in South Carolina was used to evaluate the application of the model, where the planting time of April 2 in the field study maximized the capture of solar energy for biomass production. The growth model predicts a simple linear relationship between biomass yield and the growth quantifier, which is confirmed with the data. The growth quantifier incorporates the unit processes of distribution of solar energy which drives biomass accumulation by photosynthesis, partitioning of biomass between light-gathering and structural components of the plants, and an aging function. A hyperbolic relationship between plant nutrient uptake and biomass yield is assumed, and is confirmed for the mineral elements nitrogen (N), phosphorus (P), and potassium (K). It is concluded that the rate limiting process in the system is biomass accumulation by photosynthesis and that nutrient accumulation occurs in virtual equilibrium with biomass accumulation.

Allen R. Overman; Richard V. Scholtz Iii

2011-01-01T23:59:59.000Z

489

Estimating Nonparametric Random Utility Models with an Application to the Value of Time in Heterogeneous Populations  

Science Conference Proceedings (OSTI)

The estimation of random parameters by means of mixed logit models is now current practice for the analysis of transportation behaviour. One of the most straightforward applications is the derivation of willingness-to-pay distribution over a heterogeneous ... Keywords: B-spline, constrained optimization, mixed logit, nonparametric estimation

Fabian Bastin; Cinzia Cirillo; Philippe L. Toint

2010-11-01T23:59:59.000Z

490

Real-Time Forcast Model Analysis of Daily Average Building Load for a Thermal Storage System Control  

E-Print Network (OSTI)

Thermal storage systems were originally designed to shift the on-peak cooling production to off-peak cooling production to reduce the on-peak demand. Based on the current electricity charging structure, the reduction of both on-peak and off-peak demands is becoming an exceedingly important issue. Reduction of both on-peak and off-peak demands can also extend the life span and defer or eliminate the replacement of power transformers due to potential shortage of building power capacity with anticipated equipment load increases. The next day daily average electricity demand is a critical set point to operate chillers and associated pumps at the appropriate time. For this paper, a mathematic analysis was conducted for annual daily average cooling of a building and three real-time building load forecasting models were developed. They are first-order autogressive model, random walk model and linear regression model. Finally, the comparison of results show the random walk model provides the best forecast.

Song, L.; Joo, I. S.; Guwana, S.

2009-11-01T23:59:59.000Z

491

Numerical wind speed simulation model  

DOE Green Energy (OSTI)

A relatively simple stochastic model for simulating wind speed time series that can be used as an alternative to time series from representative locations is described in this report. The model incorporates systematic seasonal variation of the mean wind, its standard deviation, and the correlation speeds. It also incorporates systematic diurnal variation of the mean speed and standard deviation. To demonstrate the model capabilities, simulations were made using model parameters derived from data collected at the Hanford Meteorology Station, and results of analysis of simulated and actual data were compared.

Ramsdell, J.V.; Athey, G.F.; Ballinger, M.Y.

1981-09-01T23:59:59.000Z

492

Explicit/multi-parametric model predictive control (MPC) of linear discrete-time systems by dynamic and multi-parametric programming  

Science Conference Proceedings (OSTI)

This work presents a new algorithm for solving the explicit/multi-parametric model predictive control (or mp-MPC) problem for linear, time-invariant discrete-time systems, based on dynamic programming and multi-parametric programming techniques. The ... Keywords: Dynamic programming, Explicit Model Predictive Control, Model Predictive Control, Multi-parametric control, Multi-parametric programming

K. I. Kouramas; N. P. Fasca; C. Panos; E. N. Pistikopoulos

2011-08-01T23:59:59.000Z

493

Impact of Distributed Generation and Series Compensation on Distribution Network  

E-Print Network (OSTI)

are investigated. A doubly-fed induction generator (DFIG)-based DG unit and a series capacitor (SC) and a thyristor DFIG units. The converter of the DFIG is modeled as an unbalanced harmonic-generating source

Pota, Himanshu Roy

494

Ownership transfer for non-federate object and time management in developing an hla compliant logistics model.  

Science Conference Proceedings (OSTI)

A seaport simulation model, PORTSIM, has been developed for the Department of Defense (DOD) at Argonne National Laboratory. PORTSIM simulates the detailed processes of cargo loading and unloading in a seaport and provides throughput capability, resource utilization, and other important information on the bottlenecks in a seaport operation, which are crucial data in determining troop and equipment deployment capability. There are two key problems to solve in developing the HLA-compliant PORTSIM model. The first is the cargo object ownership transfer problem. In PORTSIM, cargo items, e.g. vehicles, containers, and pallets, are objects having asset attributes. Cargo comes to a seaport for loading or unloading. The ownership of a cargo object transfers from its carrier to the port and then from the port to a new carrier. Each owner of the cargo object is responsible for publishing and updating the attributes of the cargo object when it has the ownership. This creates a unique situation in developing the PORTSIM federate object model, that is, the ownership of the object instead of the attributes needs to be changed in handling the cargo object in the PORTSIM federate. The ownership management service provided by the current RTI does not directly address this issue. The second is the time management issue. PORTSIM is an event-driven simulation that models seaport operations over time. To make PORTSIM HLA compliant, time management must be addressed to allow for synchronization with other simulation models. This paper attempts to address these two issues and methodologies developed for solving these two problems.

Li, Z.

1998-01-12T23:59:59.000Z

495

A new hybrid for improvement of auto-regressive integrated moving average models applying particle swarm optimization  

Science Conference Proceedings (OSTI)

A time series forecasting is an active research applied significantly in a variety of economics areas. Over the past three decades an auto-regressive integrated moving average (ARIMA) model, as one of the most important time series models, has been applied ... Keywords: ARIMA, Forecasting, PSOARIMA

Shahrokh Asadi; Akbar Tavakoli; Seyed Reza Hejazi

2012-04-01T23:59:59.000Z

496

Complex Network Approach to the Statistical Features of the Sunspot Series  

E-Print Network (OSTI)

Complex network approaches have been recently developed as an alternative framework to study the statistical features of time-series data. We perform a visibility-graph analysis on both the daily and monthly sunspot series. Based on the data, we propose two ways to construct the network: one is from the original observable measurements and the other is from a negative-inverse-transformed series. The degree distribution of the derived networks for the strong maxima has clear non-Gaussian properties, while the degree distribution for minima is bimodal. The long-term variation of the cycles is reflected by hubs in the network which span relatively large time intervals. Based on standard network structural measures, we propose to characterize the long-term correlations by waiting times between two subsequent events. The persistence range of the solar cycles has been identified over 15\\,--\\,1000 days by a power-law regime with scaling exponent $\\gamma = 2.04$ of the occurrence time of the two subsequent and successive strong minima. In contrast, a persistent trend is not present in the maximal numbers, although maxima do have significant deviations from an exponential form. Our results suggest some new insights for evaluating existing models. The power-law regime suggested by the waiting times does indicate that there are some level of predictable patterns in the minima.

Yong Zou; Michael Small; Zonghua Liu; Jrgen Kurths

2013-07-24T23:59:59.000Z

497

Learning from Time Series in the Resource-Limited Situations  

E-Print Network (OSTI)

join example on a butter?y data set. The similarity measureand texture into consideration. Data set A is for drawingsof butter?ies and data set B is for real pictures. Every

Ye, Lexiang

2010-01-01T23:59:59.000Z

498