1,721,393 research outputs found
Minimum cost path problems with relays
No full textThe minimum cost path problem with relays (MCPPR) consists of finding a minimum cost path from a source to a destination, along which relay nodes are located at a certain cost, subject to a weight constraint. This paper first models the MCPPR as a particular bicriteria path problem involving an aggregated function of the path and relay costs, as well as a weight function. A variant of this problem which takes into account all three functions separately is then considered. Formulating the MCPPR as a part of a bicriteria path problem allows the development of labeling algorithms in which the bound on the weight of paths controls the number of node labels. The algorithm for this constrained single objective function version of the problem has a time complexity of O(WmWnlog(maxW,n)), where n is the number of nodes, m is the number of arcs and W is the weight upper bound. Computational results on random instances with up to 10 000 nodes and 100 000 arcs, are reported. © 2010 Elsevier Ltd. All rights reserved
A simple enhancement of the Esau−Williams heuristic for the capacitated minimum spanning tree problem
No full text
A simple enhancement of the Esau−Williams heuristic for the capacitated minimum spanning tree problem
No full textThe pipeline and valve location problem
No full textThis paper, proposes an exact algorithm for the problem of locating a pipeline between two points of a network, as well as a set of safety valves which help control the damage caused by possible spills along the pipeline. A labelling approach is developed to determine simultaneously the optimal pipeline and valve locations, with the objective of optimising an impact measure that depends on the average number of accidents and their cost. Computational experiments on grid and random instances are presented in order to evaluate the algorithm's performance and to compare its results to the solutions provided by sequential approaches. Copyright © 2012 Inderscience Enterprises Ltd
The static bicycle relocation problem with demand intervals
Full text linkThis study introduces the Static Bicycle Relocation Problem with Demand Intervals (SBRP-DI), a variant of the One Commodity Pickup and Delivery Traveling Salesman Problem (1-PDTSP). In the SBRP-DI, the stations are required to have an inventory of bicycles lying between given lower and upper bounds and initially have an inventory which does not necessarily lie between these bounds. The problem consists of redistributing the bicycles among the stations, using a single capacitated vehicle, so that the bounding constraints are satisfied and the repositioning cost is minimized. The real-world application of this problem arises in rebalancing operations for shared bicycle systems. The repositioning subproblem associated with a fixed route is shown to be a minimum cost network problem, even in the presence of handling costs. An integer programming formulation for the SBRP-DI are presented, together with valid inequalities adapted from constraints derived in the context of other routing problems and a Benders decomposition scheme. Computational results for instances adapted from the 1-PDTSP are provided for two branch-and-cut algorithms, the first one for the full formulation, and the second one with the Benders decomposition
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