Random Utility/Multinomial Logit Model Literature Amemiya, Takeshi. 1977. "On a Two-Step Estimation,-I.-E. "Random Utility Model for Sportfishing: Some Preliminary Results for Florida." Marine extensive use of the random utility (or discrete choice) model in recent years, but few applications appear
Halton Sequences for Mixed Logit
Train, Kenneth
2000-01-01T23:59:59.000Z
Customers’ Choice Among Energy Supplier Simulation based oncustomers’ choice of energy supplier. Surveyed customerspreferences for energy suppliers, such that a mixed logit is
The Continuous Cross-Nested Logit Model: Formulation and Application for Departure Time Choice
Kockelman, Kara M.
The Continuous Cross-Nested Logit Model: Formulation and Application for Departure Time Choice modeling, departure time modeling, continuous logit, continuous cross- nested logit, Bayesian estimation usage). In this paper, the continuous cross-nested logit (CCNL) model is introduced. The CCNL model
The d-Level Nested Logit Model: Assortment and Price Optimization Problems
Topaloglu, Huseyin
The d-Level Nested Logit Model: Assortment and Price Optimization Problems Guang Li Paat, 2013 @ 2:27pm Abstract We provide a new formulation of the d-level nested logit model using a tree the optimal assort- ment. For a d-level nested logit model with n products, the running time of the algorithm
Customer-Specific Taste Parameters and Mixed Logit: Households' Choice of Electricity Supplier
Revelt, David; Train, Kenneth
2000-01-01T23:59:59.000Z
M a y 2000 Keywords: energy suppliers, mixed logit, tastecustomers' choice among energy suppliers in conjoint-typecustomers' choice o f energy supplier and estimate the value
Approximation Methods for Pricing Problems under the Nested Logit Model with Price Bounds
Topaloglu, Huseyin
Approximation Methods for Pricing Problems under the Nested Logit Model with Price Bounds W@orie.cornell.edu November 13, 2012 Abstract We consider two variants of a pricing problem under the nested logit model. In the first variant, the set of products offered to customers is fixed and we want to determine the prices
Capacity Constraints Across Nests in Assortment Optimization Under the Nested Logit Model
Topaloglu, Huseyin
Capacity Constraints Across Nests in Assortment Optimization Under the Nested Logit Model Jacob B Abstract We consider assortment optimization problems when customers choose according to the nested logit in all nests. When each product consumes one unit of capacity, our capacity constraint limits
Estimating long-term world coal production with logit and probit transforms David Rutledge
Weinreb, Sander
from measurements of coal seams. We show that where the estimates based on reserves can be testedEstimating long-term world coal production with logit and probit transforms David Rutledge form 27 October 2010 Accepted 27 October 2010 Available online 4 November 2010 Keywords: Coal reserves
Etude du choix d'acquisition d'automobiles : Application du modle probit multinomial baysien
Paris-Sud XI, UniversitÃ© de
Etude du choix d'acquisition d'automobiles : Application du modÃ¨le probit multinomial bayÃ©sien Ã l comportementale du choix individuel des agents lors d'une nouvelle acquisition automobile. En croisant les trois, Motorisation, Automobile. Classification JEL : C11 ; C25 Correspondance Ã : Roger Collet, INRETS/DEST, 2
A new method for multinomial inference using Dempster-Shafer theory
Lawrence, Earl Christopher [Los Alamos National Laboratory; Vander Wiel, Scott [Los Alamos National Laboratory; Liu, Chuanhai [PURDUE UNIV; Zhang, Jianchun [PURDUE UNIV
2009-01-01T23:59:59.000Z
A new method for multinomial inference is proposed by representing the cell probabilities as unordered segments on the unit interval and following Dempster-Shafer (DS) theory. The resulting DS posterior is then strengthened to improve symmetry and learning properties with the final posterior model being characterized by a Dirichlet distribution. In addition to computational simplicity, the new model has desirable invariance properties related to category permutations, refinements, and coarsenings. Furthemore, posterior inference on relative probabilities amongst certain cells depends only on data for the cells in question. Finally, the model is quite flexible with regard to parameterization and the range of testable assertions. Comparisons are made to existing methods and illustrated with two examples.
A Plug-in Hybrid Consumer Choice Model with Detailed Market Segmentation
Lin, Zhenhong [ORNL] [ORNL; Greene, David L [ORNL] [ORNL
2010-01-01T23:59:59.000Z
This paper describes a consumer choice model for projecting U.S. demand for plug-in hybrid electric vehicles (PHEV) in competition among 13 light-duty vehicle technologies over the period 2005-2050. New car buyers are disaggregated by region, residential area, attitude toward technology risk, vehicle usage intensity, home parking and work recharging. The nested multinomial logit (NMNL) model of vehicle choice incorporates daily vehicle usage distributions, refueling and recharging availability, technology learning by doing, and diversity of choice among makes and models. Illustrative results are presented for a Base Case, calibrated to the Annual Energy Outlook (AEO) 2009 Reference Updated Case, and an optimistic technology scenario reflecting achievement of U.S. Department of Energy s (DOE s) FreedomCAR goals. PHEV market success is highly dependent on the degree of technological progress assumed. PHEV sales reach one million in 2037 in the Base Case but in 2020 in the FreedomCARGoals Case. In the FreedomCARGoals Case, PHEV cumulative sales reach 1.5 million by 2015. Together with efficiency improvements in other technologies, petroleum use in 2050 is reduced by about 45% from the 2005 level. After technological progress, PHEV s market success appears to be most sensitive to recharging availability, consumers attitudes toward novel echnologies, and vehicle usage intensity. Successful market penetration of PHEVs helps bring down battery costs for electric vehicles (EVs), resulting in a significant EV market share after 2040.
Blanchet, Jose H.
approximation for all random utility based discrete choice models including the multinomial logit, the nested choice probabilities of a random utility discrete based choice model under mild conditions. Moreover by a customer choice model that can be thought of as distribution over preference lists (or permutations
Logit Models for Estimating Urban Area Through Travel
Talbot, Eric
2011-10-21T23:59:59.000Z
of all trips at an external station that are through trips. The second model distributes those through trips at one external station to the other external stations. The models produce separate results for commercial and non- commercial vehicles...-side interview technique at locations (called external stations) where traffic enters and exits the study area. During the daylight hours of a certain day, survey personnel would direct all vehicles or a sample of vehicles leaving the urban area to stop...
Characteristics of rural bank acquisitions: a logit analysis
Applewhite, Jennifer Lynn
1994-01-01T23:59:59.000Z
This study evaluates acquisitions of rural banks by multi-bank holding companies. Evaluation of pre-acquisition characteristics including profitability, size, market concentration, and agricultural lending volume are the basis of the analysis...
Residential mobility and location choice: a nested logit model with sampling of alternatives
Lee, Brian H.; Waddell, Paul
2010-01-01T23:59:59.000Z
Waddell, P. : Modeling residential location in UrbanSim. In:D. (eds. ) Modelling Residential Location Choice. Springer,based model system and a residential location model. Urban
Joint mixed logit models of stated and revealed preferences for alternative-fuel vehicles
Brownston, David; Bunch, David S.; Train, Kenneth
1999-01-01T23:59:59.000Z
for forecasting demand for alternative-fuel vehicles. In:preferences for alternative-fuel vehicles David Brownstonespondents' preferences for alternative-fuel vehicles. The e€
Dickinson, Brenton J
2010-01-01T23:59:59.000Z
??The Family Forest Research Center recently conducted a mail survey of about 1,400 Massachusetts landowners. Respondents were given questions about themselves and their land and… (more)
Bains, Amrit Anoop Singh
2010-10-12T23:59:59.000Z
technical challenges, which has lead to escalation of danger on a construction site. Data from OSHA show that crane accidents have increased rapidly from 2000 to 2004. By analyzing the characteristics of all the crane accident inspections, we can better...
Russell, Jeffrey; Engle, Robert F
1998-01-01T23:59:59.000Z
Lancaster, T. , 1990, The Econometric Analysis of TransitionDEPARTMENT OF ECONOMICS ECONOMETRIC ANALYSIS OF DISCRETE-PAPER 98-10 APRIL 1998 Econometric analysis of discrete-
Examining solid waste management issues in the City of Bryan
Arekere, Dhananjaya Marigowda
2006-04-12T23:59:59.000Z
for Policy II with Mail-Unconsolidated Data ............. Logit Results for Policy II with Mail-Consolidated Data ............... Logit Results for Policy II with Pooled-Unconsolidated Data ........... Logit Results for Policy II with Pooled-Consolidated Data... for Policy III with Mail-Unconsolidated Data ............ Logit Results for Policy III with Mail-Consolidated Data ............. Logit Results for Policy III with Pooled-Unconsolidated Data .......... Logit Results for Policy III with Pooled...
California at Berkeley, University of
-aided manufacturing practices and statistical process control practices in addition to commonly cited practices improvement rates of the fabs are compared, and manufacturing yield improve- ment practices are evaluated such as particle control and advanced manufacturing technology. #12;Introduction The results of a world-wide study
Future Potential of Hybrid and Diesel Powertrains in the U.S. Light-duty Vehicle Market
Greene, D.L.
2004-08-23T23:59:59.000Z
Diesel and hybrid technologies each have the potential to increase light-duty vehicle fuel economy by a third or more without loss of performance, yet these technologies have typically been excluded from technical assessments of fuel economy potential on the grounds that hybrids are too expensive and diesels cannot meet Tier 2 emissions standards. Recently, hybrid costs have come down and the few hybrid makes available are selling well. Diesels have made great strides in reducing particulate and nitrogen oxide emissions, and are likely though not certain to meet future standards. In light of these developments, this study takes a detailed look at the market potential of these two powertrain technologies and their possible impacts on light-duty vehicle fuel economy. A nested multinomial logit model of vehicle choice was calibrated to 2002 model year sales of 930 makes, models and engine-transmission configurations. Based on an assessment of the status and outlook for the two technologies, market shares were predicted for 2008, 2012 and beyond, assuming no additional increase in fuel economy standards or other new policy initiatives. Current tax incentives for hybrids are assumed to be phased out by 2008. Given announced and likely introductions by 2008, hybrids could capture 4-7% and diesels 2-4% of the light-duty market. Based on our best guesses for further introductions, these shares could increase to 10-15% for hybrids and 4-7% for diesels by 2012. The resulting impacts on fleet average fuel economy would be about +2% in 2008 and +4% in 2012. If diesels and hybrids were widely available across vehicle classes, makes, and models, they could capture 40% or more of the light-duty vehicle market.
A Quantitative Analysis of Previously Launched Adults
Farris, Demetrea Nicole
2012-02-14T23:59:59.000Z
" of either previously launched or failure to launch. I undertake two multinomial logistic regression models with the dependent variable "launching status." I then proceed to a replication of the original analysis with two other multinomial logistic regression...
Wood, D.J.
2010-01-01T23:59:59.000Z
only logit estimate variable name normalized capital costcost estimates by using construction handbooks (for capitalcapital cost coefficient to operating cost coefficient gives an estimate
Sensitivity analysis of the optimal solutions to Huff-type competitive ...
2008-11-26T23:59:59.000Z
facilities and the distances to them, through a gravitational or logit type model. Both the ..... This generalizes the 'law of retail gravitation' of Reilly [33], who.
Miao, Jingang
2014-05-30T23:59:59.000Z
As a probabilistic statistical classification model, logistic regression (or logit regression) is widely used to model the outcome of a categorical dependent variable based on one or more predictor variables/features. We study two problems related...
Kapilakanchana, Montalee
2012-07-16T23:59:59.000Z
an econometric model with discrete choice modeling approaches: logit and probit. There are two main hypotheses. Firstly, it is hypothesized that branding decreases the likelihood of the occurrence of the repeated recall event. Secondly, size of the firm...
Patterns of Identification: The Children of Latino/Non-Latino White Families
Fox, Amber
2012-02-14T23:59:59.000Z
and ethnically identify their children. Specifically, I use both multinomial logistic regression and multilevel binomial logistic regression to predict the outcome of the child either being identified as Latino (white or other) or non-Latino (white or other...
ICPSR Summer Program Comparing groups in
Indiana University
year+ yearsq Pr tenure 1| select articles fema pre i e h l st year yearsq s female elect articles presthi E E E E E E E Â§ Â· /Â¨ Â¸ Â© Â¹ x logit (N=2797): Factor Change in Odds Odds of: Tenure vs No
The Drivers of Mergers and Acquisitions in Pharmaceutical Industry
Ji, Fan
2012-07-16T23:59:59.000Z
We examine the determinants and drivers of 112 mergers and acquisitions (M&A) activities exceed 50 million values in the pharmaceutical industry using COMPUSTAT, SDC and FDA data during the period 1980-2010 with random effect logit model. We find...
GENERATING MOMENT MATCHING SCENARIOS USING ...
David
2013-01-31T23:59:59.000Z
Jan 29, 2013 ... where f is a convex (hence, continuous) real-valued function, ... In this paper we revisit the classic idea of “polynomial exactness” in the theory of cubature ..... two compendiums of such formulas: Stroud's classic book [29], and the ...... We used random density functions from the multivariate logit-normal ...
Jeremy J. Michalek1 e-mail: michalek@umich.edu
Papalambros, Panos
, and manufacturing costs are developed for a specific market segment, and game theory is utilized to simulate Theory; Oligopoly; Emis- sions; CAFE; Discrete Choice Analysis; Econometrics; Logit; Green Engineering 1- tomotive manufacturing, profitability depends upon a vehicle's en- gineering performance and cost, as well
Optimized Cascade of Classifiers for People Detection Using Covariance Malik SOUDED1,2
Paris-Sud XI, UniversitÃ© de
for many applications like people track- ing especially in crowded scenes has motivated many researchesOptimized Cascade of Classifiers for People Detection Using Covariance Features Malik SOUDED1.Souded@digitalbarriers.com Keywords: People detection, Covariance descriptor, LogitBoost. Abstract: People detection on static images
Kundu, Debasis
Journal of Transportation Engineering Modelling Automobile Driver's Toll-Lane Choice Behaviour at a Toll Plaza --Manuscript Draft-- Manuscript Number: TEENG-1181R3 Full Title: Modelling Automobile Driver to develop a random utility based discrete multinomial choice model for the behaviour of automobile drivers
Machine Learning ! ! ! ! ! Srihari Parameter Estimation for
Â· Bayesian Approach ÂThumbtack vs Coin Toss Â· Uniform Prior vs Beta Prior ÂMultinomial Â· Dirichlet Prior 2 Â· Statistical estimation theory deals with Confidence Intervals ÂE.g., in election polls 61 + 2 percent plan
{beta}-delayed neutron decay of {sup 14}Be
Belbot, M.D.; Kolata, J.J.; Lamkin, K.; Tighe, R.J.; Zahar, M. [Physics Department, University of Notre Dame, Notre Dame, Indiana 46556 (United States)] [Physics Department, University of Notre Dame, Notre Dame, Indiana 46556 (United States); Harkewicz, R.; Morrissey, D.J.; Orr, N.A.; Ronningen, R.M.; Sherrill, B.M.; Winger, J.A. [Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States)] [Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States); Carpenter, M. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)] [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)
1995-05-01T23:59:59.000Z
The neutron spectroscopy of the {beta}-delayed neutron decay of {sup 14}Be has been investigated. Two neutron groups were observed, and energy limits are given for a third (unobserved) group that receives most of the {beta}-decay strength. Branching ratios and log{ital ft} values deduced for all three groups are compared with the results of a shell-model calculation.
Two Essays on Premarital Cohabitation and Divorce
Liu, Chia-Hua
2013-12-09T23:59:59.000Z
. . . . . . . . . . . . . . . . . . . . . . . . . . . 13 3.2.1 An overview of marital outcome . . . . . . . . . . . . . . . . . 13 3.2.2 Descriptive statistics for control variables . . . . . . . . . . . . 14 3.3 Results for linear probability models . . . . . . . . . . . . . . . . . . 17 3.4... The empirical setting of a nested logit model . . . . . . . . . . . . . . 21 3.4.1 An individual’s union history . . . . . . . . . . . . . . . . . . 21 3.4.2 Construct a choice set . . . . . . . . . . . . . . . . . . . . . . 22 3.4.3 Generate counterfactual...
Sporadic voters: how attitude change influences voter turnout
Owens, Christopher T.
2009-06-02T23:59:59.000Z
????????????????????......................... 126 VITA????????????????????????????? 131 x LIST OF FIGURES FIGURE Page 1.1 Presidentical Election Turnout 1960-2004?????????.. 10 2.1 General Election Turnout 1980-2004???????????.. 31 xi LIST OF TABLES TABLE Page... for All Respondents Casting a Ballot in 1976? 61 3.10 Logit Coefficients for All Respondents Casting a Ballot in 1992? 64 4.1 Mean Values on Independent Variables for Respondents in the 1972-1974 NES Panel????????????????? 74 4.2 Change in Values...
Home-based work, human capital accumulation and women's labor force participation
Chutubtim, Piyaluk
2006-10-30T23:59:59.000Z
????????????????????????... 78 2 Proportion of Home-Based Workers, by Year and Occupation?????. 79 3 Socioeconomic Characteristics of Women Aged 25 to 54, by Work Status and Work Site????????????????????????. 80 4 Logit Coefficients from Edwards and Field... to wage and salary workers and divides workers by sex, age, and education. He concludes that, overtime, wage penalties on home-based work have become smaller relative to on-site work. The increase in the employment shares and relative wages of home...
Crop acreage estimators based on satellite imagery
Vidart, Stephane
1983-01-01T23:59:59.000Z
acreages have been pooled during the creation of the two data sets. Each data set refers to a particular part of the state of Texas. The two regions are shown in Figure 1. The partitioning is made according to crop reporting districts (CRD), which... studies are reported: (1) a comparison of sample behavior with theoretical asymptotic behavior, (2) an evaluation using CAMS data and fixed size sampling units of the improvement of the estimators under the new decision process over the old multinomial...
Peterson, James T.
1999-12-01T23:59:59.000Z
Natural resource professionals are increasingly required to develop rigorous statistical models that relate environmental data to categorical responses data. Recent advances in the statistical and computing sciences have led to the development of sophisticated methods for parametric and nonparametric analysis of data with categorical responses. The statistical software package CATDAT was designed to make some of these relatively new and powerful techniques available to scientists. The CATDAT statistical package includes 4 analytical techniques: generalized logit modeling; binary classification tree; extended K-nearest neighbor classification; and modular neural network.
Finding a Minimally Informative Dirichlet Prior Distribution Using Least Squares
Dana Kelly; Corwin Atwood
2011-03-01T23:59:59.000Z
In a Bayesian framework, the Dirichlet distribution is the conjugate distribution to the multinomial likelihood function, and so the analyst is required to develop a Dirichlet prior that incorporates available information. However, as it is a multiparameter distribution, choosing the Dirichlet parameters is less straight-forward than choosing a prior distribution for a single parameter, such as p in the binomial distribution. In particular, one may wish to incorporate limited information into the prior, resulting in a minimally informative prior distribution that is responsive to updates with sparse data. In the case of binomial p or Poisson, the principle of maximum entropy can be employed to obtain a so-called constrained noninformative prior. However, even in the case of p, such a distribution cannot be written down in closed form, and so an approximate beta distribution is used in the case of p. In the case of the multinomial model with parametric constraints, the approach of maximum entropy does not appear tractable. This paper presents an alternative approach, based on constrained minimization of a least-squares objective function, which leads to a minimally informative Dirichlet prior distribution. The alpha-factor model for common-cause failure, which is widely used in the United States, is the motivation for this approach, and is used to illustrate the method. In this approach to modeling common-cause failure, the alpha-factors, which are the parameters in the underlying multinomial aleatory model for common-cause failure, must be estimated from data that is often quite sparse, because common-cause failures tend to be rare, especially failures of more than two or three components, and so a prior distribution that is responsive to updates with sparse data is needed.
Finding A Minimally Informative Dirichlet Prior Using Least Squares
Dana Kelly
2011-03-01T23:59:59.000Z
In a Bayesian framework, the Dirichlet distribution is the conjugate distribution to the multinomial likelihood function, and so the analyst is required to develop a Dirichlet prior that incorporates available information. However, as it is a multiparameter distribution, choosing the Dirichlet parameters is less straightforward than choosing a prior distribution for a single parameter, such as p in the binomial distribution. In particular, one may wish to incorporate limited information into the prior, resulting in a minimally informative prior distribution that is responsive to updates with sparse data. In the case of binomial p or Poisson \\lambda, the principle of maximum entropy can be employed to obtain a so-called constrained noninformative prior. However, even in the case of p, such a distribution cannot be written down in the form of a standard distribution (e.g., beta, gamma), and so a beta distribution is used as an approximation in the case of p. In the case of the multinomial model with parametric constraints, the approach of maximum entropy does not appear tractable. This paper presents an alternative approach, based on constrained minimization of a least-squares objective function, which leads to a minimally informative Dirichlet prior distribution. The alpha-factor model for common-cause failure, which is widely used in the United States, is the motivation for this approach, and is used to illustrate the method. In this approach to modeling common-cause failure, the alpha-factors, which are the parameters in the underlying multinomial model for common-cause failure, must be estimated from data that are often quite sparse, because common-cause failures tend to be rare, especially failures of more than two or three components, and so a prior distribution that is responsive to updates with sparse data is needed.
Analyzing Data for Systems Biology: Working at the Intersection of Thermodynamics and Data Analytics
Cannon, William R.; Baxter, Douglas J.
2012-08-15T23:59:59.000Z
Many challenges in systems biology have to do with analyzing data within the framework of molecular phenomena and cellular pathways. How does this relate to thermodynamics that we know govern the behavior of molecules? Making progress in relating data analysis to thermodynamics is essential in systems biology if we are to build predictive models that enable the field of synthetic biology. This report discusses work at the crossroads of thermodynamics and data analysis, and demonstrates that statistical mechanical free energy is a multinomial log likelihood. Applications to systems biology are presented.
User's manual for geophysical well-logging software programs
Petrie, G.M.; Gibson, D.; Blair, S.C.
1983-02-01T23:59:59.000Z
Since 1958 the Ground-Water Surveillance Program for the Hanford Site has made geophysical logging measurements in most of the 800 wells and deep boreholes that have been drilled on the Hanford Site. In 1980 the Pacific Northwest Laboratory (PNL), which conducts the Ground-Water Surveillance Program, began forming a computerized data base for storing and retrieving geophysical well log data and developing software for quantitative analysis of the well log data. This report, designed to serve as a user's guide, documents the data base system that handles the well log data. Two programs, DIGLOG1 and LOGIT, are used to manipulate the data. The program DIGLOG1 translates analog paper strip charts into digital format; the program LOGIT is a general utility program that edits, displays, checks, stores, writes, and deletes sets of well log data. These two programs do not provide sophisticated display and analytical capabilities; rather, they provide programs that give the user easy access to powerful standard analytical software.
MODELING THE DEMAND FOR E85 IN THE UNITED STATES
Liu, Changzheng [ORNL; Greene, David L [ORNL
2013-10-01T23:59:59.000Z
How demand for E85 might evolve in the future in response to changing economics and policies is an important subject to include in the National Energy Modeling System (NEMS). This report summarizes a study to develop an E85 choice model for NEMS. Using the most recent data from the states of Minnesota, North Dakota, and Iowa, this study estimates a logit model that represents E85 choice as a function of prices of E10 and E85, as well as fuel availability of E85 relative to gasoline. Using more recent data than previous studies allows a better estimation of non-fleet demand and indicates that the price elasticity of E85 choice appears to be higher than previously estimated. Based on the results of the econometric analysis, a model for projecting E85 demand at the regional level is specified. In testing, the model produced plausible predictions of US E85 demand to 2040.
Boer, Rizaldi; Wasrin, Upik R.; Hendri, Perdinan; Dasanto,Bambang D.; Makundi, Willy; Hero, Julius; Ridwan, M.; Masripatin, Nur
2007-06-01T23:59:59.000Z
Rehabilitation of degraded forest land throughimplementation of carbon sink projects can increase terrestrial carbonstock. However, carbon emissions outside the project boundary, which iscommonly referred to as leakage, may reduce or negate the sequestrationbenefits. This study assessed leakage from carbon sink projects thatcould potentially be implemented in the study area comprised of elevensub-districts in the Batanghari District, Jambi Province, Sumatra,Indonesia. The study estimates the probability of a given land use/coverbeing converted into other uses/cover, by applying a logit model. Thepredictor variables were: proximity to the center of the land use area,distance to transportation channel (road or river), area of agriculturalland, unemployment (number of job seekers), job opportunities, populationdensity and income. Leakage was estimated by analyzing with and withoutcarbon sink projects scenarios. Most of the predictors were estimated asbeing significant in their contribution to land use cover change. Theresults of the analysis show that leakage in the study area can be largeenough to more than offset the project's carbon sequestration benefitsduring the period 2002-2012. However, leakage results are very sensitiveto changes of carbon density of the land uses in the study area. Byreducing C-density of lowland and hill forest by about 10 percent for thebaseline scenario, the leakage becomes positive. Further data collectionand refinement is therefore required. Nevertheless, this study hasdemonstrated that regional analysis is a useful approach to assessleakage.
Maximum entropy principal for transportation
Bilich, F. [University of Brasilia (Brazil); Da Silva, R. [National Research Council (Brazil)
2008-11-06T23:59:59.000Z
In this work we deal with modeling of the transportation phenomenon for use in the transportation planning process and policy-impact studies. The model developed is based on the dependence concept, i.e., the notion that the probability of a trip starting at origin i is dependent on the probability of a trip ending at destination j given that the factors (such as travel time, cost, etc.) which affect travel between origin i and destination j assume some specific values. The derivation of the solution of the model employs the maximum entropy principle combining a priori multinomial distribution with a trip utility concept. This model is utilized to forecast trip distributions under a variety of policy changes and scenarios. The dependence coefficients are obtained from a regression equation where the functional form is derived based on conditional probability and perception of factors from experimental psychology. The dependence coefficients encode all the information that was previously encoded in the form of constraints. In addition, the dependence coefficients encode information that cannot be expressed in the form of constraints for practical reasons, namely, computational tractability. The equivalence between the standard formulation (i.e., objective function with constraints) and the dependence formulation (i.e., without constraints) is demonstrated. The parameters of the dependence-based trip-distribution model are estimated, and the model is also validated using commercial air travel data in the U.S. In addition, policy impact analyses (such as allowance of supersonic flights inside the U.S. and user surcharge at noise-impacted airports) on air travel are performed.
Bakhshandeh, Mohsen [Department of Medical Physics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran (Iran, Islamic Republic of)] [Department of Medical Physics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran (Iran, Islamic Republic of); Hashemi, Bijan, E-mail: bhashemi@modares.ac.ir [Department of Medical Physics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran (Iran, Islamic Republic of)] [Department of Medical Physics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran (Iran, Islamic Republic of); Mahdavi, Seied Rabi Mehdi [Department of Medical Physics, Faculty of Medical Sciences, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of)] [Department of Medical Physics, Faculty of Medical Sciences, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Nikoofar, Alireza; Vasheghani, Maryam [Department of Radiation Oncology, Hafte-Tir Hospital, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of)] [Department of Radiation Oncology, Hafte-Tir Hospital, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Kazemnejad, Anoshirvan [Department of Biostatistics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran (Iran, Islamic Republic of)] [Department of Biostatistics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran (Iran, Islamic Republic of)
2013-02-01T23:59:59.000Z
Purpose: To determine the dose-response relationship of the thyroid for radiation-induced hypothyroidism in head-and-neck radiation therapy, according to 6 normal tissue complication probability models, and to find the best-fit parameters of the models. Methods and Materials: Sixty-five patients treated with primary or postoperative radiation therapy for various cancers in the head-and-neck region were prospectively evaluated. Patient serum samples (tri-iodothyronine, thyroxine, thyroid-stimulating hormone [TSH], free tri-iodothyronine, and free thyroxine) were measured before and at regular time intervals until 1 year after the completion of radiation therapy. Dose-volume histograms (DVHs) of the patients' thyroid gland were derived from their computed tomography (CT)-based treatment planning data. Hypothyroidism was defined as increased TSH (subclinical hypothyroidism) or increased TSH in combination with decreased free thyroxine and thyroxine (clinical hypothyroidism). Thyroid DVHs were converted to 2 Gy/fraction equivalent doses using the linear-quadratic formula with {alpha}/{beta} = 3 Gy. The evaluated models included the following: Lyman with the DVH reduced to the equivalent uniform dose (EUD), known as LEUD; Logit-EUD; mean dose; relative seriality; individual critical volume; and population critical volume models. The parameters of the models were obtained by fitting the patients' data using a maximum likelihood analysis method. The goodness of fit of the models was determined by the 2-sample Kolmogorov-Smirnov test. Ranking of the models was made according to Akaike's information criterion. Results: Twenty-nine patients (44.6%) experienced hypothyroidism. None of the models was rejected according to the evaluation of the goodness of fit. The mean dose model was ranked as the best model on the basis of its Akaike's information criterion value. The D{sub 50} estimated from the models was approximately 44 Gy. Conclusions: The implemented normal tissue complication probability models showed a parallel architecture for the thyroid. The mean dose model can be used as the best model to describe the dose-response relationship for hypothyroidism complication.
WAPDEG Analysis of Waste Package and Drip shield Degradation
K. Mon
2004-09-29T23:59:59.000Z
As directed by ''Technical Work Plan for: Regulatory Integration Modeling and Analysis of the Waste Form and Waste Package'' (BSC 2004 [DIRS 171583]), an analysis of the degradation of the engineered barrier system (EBS) drip shields and waste packages at the Yucca Mountain repository is developed. The purpose of this activity is to provide the TSPA with inputs and methodologies used to evaluate waste package and drip shield degradation as a function of exposure time under exposure conditions anticipated in the repository. This analysis provides information useful to satisfy ''Yucca Mountain Review Plan, Final Report'' (NRC 2003 [DIRS 163274]) requirements. Several features, events, and processes (FEPs) are also discussed (Section 6.2, Table 15). The previous revision of this report was prepared as a model report in accordance with AP-SIII.10Q, Models. Due to changes in the role of this report since the site recommendation, it no longer contains model development. This revision is prepared as a scientific analysis in accordance with AP-SIII.9Q, ''Scientific Analyses'' and uses models previously validated in (1) ''Stress Corrosion Cracking of the Drip Shield, the Waste Package Outer Barrier, and the Stainless Steel Structural Material'' (BSC 2004 [DIRS 169985]); (2) ''General Corrosion and Localized Corrosion of Waste Package Outer Barrier'' (BSC 2004 [DIRS 169984]); and (3) ''General Corrosion and Localized Corrosion of Drip Shield'' (BSC 2004 [DIRS 169845]). The integrated waste package degradation (IWPD) analysis presented in this report treats several implementation-related issues, such as defining the number and size of patches per waste package that undergo stress corrosion cracking; recasting the weld flaw analysis in a form as implemented in the Closure Weld Defects (CWD) software; and, general corrosion rate manipulations (e.g., change of scale in Section 6.3.4). The weld flaw portion of this report takes input from an engineering calculation (BSC 2004 [DIRS 170024]) and uses standard mathematical methods to enable easier implementation. The IWPD analysis also provides guidance on implementation of early failures (importance sampling and multinomial distribution usage). These manipulations are evident from standard scientific practices, approaches, or methods and do not require changes to the previously validated models. The IWPD analysis itself (Section 6.4), not the resultant curves from executing the IWPD analysis presented in Section 6.5 (which are for illustrative purposes), is used directly in total system performance assessment (TSPA). The IWPD analysis simulates general corrosion and stress corrosion cracking of the waste package outer barrier and general corrosion of the drip shield. The effects of igneous and seismic events and localized corrosion on drip shield and waste package performance are not evaluated in this report. The outputs of this report are inputs and methodologies used by TSPA to evaluate waste package and drip shield degradation as a function of exposure time under exposure conditions anticipated in the repository. The analyses presented in this report are for the current repository design (BSC 2004 [DIRS 168489]).