Multi-depot Location-Routing Problem (MDLRP) is about finding the optimal number and locations of depots while allocating customers to depots and determining vehicle routes to visit all customers. In this study we propose a nested Lagrangian relaxation-based method for the discrete uncapacitated MDLRP. An outer Lagrangian relaxation embedded in subgradient optimization decomposes the parent pro...

This paper presents a discussion arisen after reading ”A hybrid genetic algorithm that optimizes capacitated vehicle routing problem”, by Chung-Ho Wang and Jiu-Zhang Lu, (2009). Expert System with Applications (35)(pp. 2921-2936). The discussed paper presents a hybrid genetic algorithm applied to the Capacitated Vehicle Routing Problem (CVRP). When the authors present the results obtained by th...

Precision farming in viticulture raises challenging combinatorial issues such as the Differential Harvest Problem . This problem might appear at first similar to a simple Capacitated Vehicle Routing but it exhibits problem-specific constraints that make this much harder solve and which are discussed article. Our objective was develop efficient exact methods using column generation VRPSolver™ ba...

Assignment problem in content distribution networks (CDN) is unsplittable hard-capacitated facility location problem (UHCFLP) because of underlying anycast routing protocol. We extend assignment problem in CDN to multidimensional facility location problem (MFLP). With our devised algorithm, assignment cost considers CPU utilization parameter along with request size and distance between client a...

In this paper we present a 1.52-approximation algorithm for the metric uncapacitated facility location problem, and a 2-approximation algorithm for the metric capacitated facility location problem with soft capacities. Both these algorithms improve the best previously known approximation factor for the corresponding problem, and our soft-capacitated facility location algorithm achieves the inte...

In this paper we define a new approach to solve the location routing problem (LRP). LRP is a relatively new research direction within location analysis that takes into account vehicle routing aspects. In this study it is proposed an iterative two phase search based heuristic method to solve a capacitated location routing problem. At first an initial solution is produced by a greedy approach and...