Network improvement problems

Conference · Fri Sep 01 04:00:00 EDT 1995

OSTI ID:106605

Krumke, S O; Noltemeier, H; Drangmeister, K U ^[1]; Marathe, M V ^[2]; Ravi, S S ^[3]

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1. Univ. of Wuerzburg (Germany). Dept. of Computer Science
2. Los Alamos National Lab., NM (United States)
3. State Univ. of New York, Albany, NY (United States). Dept. of Computer Science

The authors study budget constrained optimal network improvement problems. Such problems aim at finding optimal strategies for improving a network under some cost measure subject to certain budget constraints. As an example, consider the following prototypical problem: Let G = (V, E) be an undirected graph with two cost values L(e) and C(e) associated with each edge e, where L(e) denotes the length of e and C(e) denotes the cost of reducing the length of e by a unit amount. A reduction strategy specifies for each edge e, the amount by which L(e) is to be reduced. For a given budget B, the goal is to find a reduction strategy such that the total cost of reduction is at most B and the minimum cost tree (with respect to some measure M) under the modified L costs is the best over all possible reduction strategies which obey the budget constraint. Typical measures M for a tree are the total weight and the diameter. They provide both hardness and approximation results for the two measures M mentioned above. For the problem of minimizing the total weight of a spacing tree, they provide an algorithm that, for any fixed {gamma},{var_epsilon} > 0, finds a solution whose weight is at most (1 + 1/{gamma}) times that of a minimum length spanning tree plus an additive constant of at most {var_epsilon} and the total cost of improvement is at most (1 + {gamma}) times the budget B. This result can be extended to obtain approximation algorithms for more general network design problems considered in [GW, GG+94].

• Research Organization: Los Alamos National Lab., NM (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 106605
• Report Number(s): LA-UR--95-2925; CONF-9501107--1; CONF-960769--1; ON: DE96000030
• Country of Publication: United States
• Language: English

Related Subjects

99 GENERAL AND MISCELLANEOUS
ALGORITHMS
COMPUTER NETWORKS
DATA TRANSMISSION
DESIGN
OPTIMIZATION
PERFORMANCE