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...

A approximation algorithm for an optimization problem runs in polynomial time for all instances and is guaranteed to deliver solutions with bounded optimality gap. We derive such algorithms for different variants of capacitated location routing, an important generalization of vehicle routing where the cost of opening the depots from which vehicles operate is taken into account. Our results orig...

The Capacitated Vehicle Routing Problem with Balanced Routes and Time Windows (CVRPBRTW) aims at optimizing the total distance cost, the number of vehicles used, and the route balancing subject to time windows and other constraints. Due to the multiple and often conflicting objectives, the proposed problem is formulated and tackled in a MultiObjective Optimization manner using a Hybrid Multi-Ob...

The talk presents two non-standard extensions for singlevehicle arc-routing problems a.k.a. postman problems: First, street segments that require a service on both sides of the street can be covered either by two separate services or by a single zigzag service. Instead of deciding the type of service beforehand, we propose to take into account the zigzagging option when designing a tour. We pre...

Multi-objective capacitated multiple allocation hub location problem (MOCMAHLP) is a variation of classic problem, which deals with network design, considering both the number and hubs connections between spokes, as well routing flow on network. In this study, we offer two meta-heuristic approaches based non-dominated sorting genetic algorithm (NSGA-II) archived multi-objective simulated anneal...

Vehicle Routing Problem (VRP) is addressed to a class of problems for determining a set of vehicle routes, in which each vehicle departs from a given depot, serves a given set of customers, and returns back to the same depot. On the other hand, simultaneous delivery and pickup problems have drawn much attention in the past few years due to its high usage in real world cases. This study, therefo...

This chapter is devoted to surveying aspects of computational complexity for three central arc routing problems (and their corresponding variants): • Chinese Postman, where one asks for a minimum-cost tour traversing all edges of a graph at least once; • Rural Postman, which generalizes Chinese Postman in the sense that only a subset of the edges has to be visited; • Capacitated Arc Routing, re...