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Discrete Network Design Using Parallel Branch-and-Bound Algorithms
,
M.Sc. Thesis
Sharif University of Technology
;
hafahi, Yusof
(Supervisor)
Abstract
Discrete Network Design (DND) is a classical combinatorial problem in transportation planning. According to its exponential nature, the problem has a costly exact solution. In recent decades, however, the advent of parallel computing facilities motivated researchers to apply exact solutions on many combinatorial problems. As a result, parallel Branch-and-Bound (B&B) algorithms emerged as robust methods to address combinatorial problems. This dissertation will investigate the parallel behavior of B&B algorithms in DND through some case studies. Parallelization results suggest that parallel B&B algorithms can achieve linear speed-ups in DND for a large number of processors
Comparing Meta-Heuristic Algorithms for Solving Transportation Network Design Problem
, M.Sc. Thesis Sharif University of Technology ; Zokaei Aashtiani, Hedayat (Supervisor)
Abstract
Discrete network design problem is selecting a set of feasible projects among a set of candidate projects, considering a budget constraint in which user's cost is being minimized. Network design problem is one of the complicated problems in transportation science, since it is a bi-level problem in which the lower level is a traffic assignment problem and the upper level is finding the best set of arcs. Meta-heuristic algorithms can be used to solve this problem. Although, there is no guarantee to find the optimal solution by Meta-heuristic algorithms, but they find good solutions in short times. The purpose of this study is comparing the efficiency of three Meta-heuristic algorithms for...
Toward equitable investment in transport infrastructures: Providing a comparative framework based on theories of justice
, Article Middle - East Journal of Scientific Research ; Vol. 19, issue. 9 , 2014 , pp. 1215-1225 ; ISSN: 19909233 ; Nazari, S ; Jahromi, H. N ; Sharif University of Technology
Abstract
Equity in distribution is one of the most controversial and essential concepts which for a long time has been the central concern of political philosophers when considering planning concerns of the societies. Transport is a key field by which politicians and decision-makers impose their intention on societies. Although there have been studies discussing equity in transport, yet there is no clear mathematical framework to utilize the equity concept in transportation planning. This study has reviewed equity in transportation, as well as in human science studies to investigate and determine how transportation advantages should be equitably distributed among society members. This review has led...
Parallelization of the branch-and-bound algorithm in transportation discrete network design problem
, Article Scientia Iranica ; Volume 23, Issue 2 , 2016 , Pages 407-419 ; 10263098 (ISSN) ; Shafahi, Y ; Sharif University of Technology
Sharif University of Technology
Abstract
Transportation Discrete Network Design Problem (TDNDP) aims at choosing a subset of proposed projects to minimize the users' total travel time with respect to a budget constraint. Because TDNDP is a hard combinatorial problem, recent research has widely addressed heuristic approaches and ignored the exact solution. This paper explores how application of parallel computation can affect the performance of an exact algorithm in TDNDP. First, we show that the Branch-and-Bound (B&B) algorithm, proposed by LeBlanc, is well adapted to a parallel design with synchronized Master-Slave (MS) paradigm. Then, we develop a parallel B&B algorithm and implement it with two search strategies of...
Accelerating the performance of parallel depth-first-search branch-and-bound algorithm in transportation network design problem
, Article ICORES 2015 - 4th International Conference on Operations Research and Enterprise Systems, Proceedings, 10 January 2015 through 12 January 2015 ; January , 2015 , Pages 359-366 ; 9789897580758 (ISBN) ; Shafahi, Y ; Sharif University of Technology
SciTePress
2015
Abstract
Transportation Network Design Problem (TNDP) aims at selection of a subset of proposed urban projects in budget constraint to minimize the network users' total travel time. This is a well-known resource-intensive problem in transportation planning literature. Application of parallel computing, as a result, can be useful to address the exact solution of TNDP. This paper is going to investigate how the performance of a parallel Branch-and-Bound (B&B) algorithm with Depth-First-Search (DFS) strategy can be accelerated. The paper suggests assigning greedy solutions to idle processors at the start of the algorithm. A greedy solution, considered in this paper, is a budget-wise feasible selection...