1,720,986 research outputs found
A non linear multicommodity network design approach to solve a location-allocation problem in freight transportation
No full textAn Exact Method for the Capacitated Location-Routing Problem
No full textThe capacitated location-routing problem (LRP) consists of opening one or more depots on a given set of a-priori defined
depot locations, and designing, for each opened depot, a number of routes in order to supply the demands of a given set
of customers. With each depot are associated a fixed cost for opening it and a capacity that limits the quantity that can be
delivered to the customers. The objective is to minimize the sum of the fixed costs for opening the depots and the costs of
the routes operated from the depots.
This paper describes a new exact method for solving the LRP based on a set-partitioning-like formulation of the problem.
The lower bounds produced by different bounding procedures, based on dynamic programming and dual ascent methods,
are used by an algorithm that decomposes the LRP into a limited set of multicapacitated depot vehicle-routing problems
(MCDVRPs).
Computational results on benchmark instances from the literature show that the proposed method outperforms the current
best-known exact methods, both for the quality of the lower bounds achieved and the number and the dimensions of the
instances solved to optimality
A heuristic approach to the overnight security service problem
No full textThis paper introduces the overnight security service problem. The model obtained is a single-objective mixed integer programming problem. It is NP-hard in the strong sense, and exact approaches are not practicable when solving real-life instances. Thus, the model is solved heuristically, through a decomposition in two subproblem. The former is a capacitated clustering problem, the latter is a multiple travelling salesman problem with time windows. Both have a radius constraint which is unusual. The computational results prove the robustness of the approach used. Moreover, a detailed discussion of the results shows that the management objectives are satisfied, providing lower costs, a strong guarantee on the level of service and several different solutions
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