Many exact and approximate solution techniques have been used to solve facility location problems and, more generally, supply chain network design problems. Yet, the Large Neighborhood Search technique (LNS) has almost never been suggested for solving such problems, although it has proven its efficiency and flexibility in solving other complex combinatorial optimization problems. In this paper,...

In this paper we consider the well known p-median problem. We study the behavior of the local improvement algorithm with a new large neighborhood. Computational experiments on the difficult instances show that the algorithm with the neighborhood is fast and finds feasible solutions with small relative error.

Dial-a-Ride problems (DARPs) arise in many urban transportation applications. The core of a DARP is a pick and delivery routing with multiple vehicles in which customers have ride-time constraints and routes have a maximum duration. This paper considers DARPs for which the objective is to minimize the routing cost, a complex optimization problem which has been studied extensively in the past. S...

A combinatorial optimization problem (COP) P consists of a collection of its instances. An instance of P can be represented as an ordered pair (F, f), where F is the family of feasible solutions and f is the objective function which is used to compare two feasible solutions. The family F is formed by subsets of a finite set E = {1, 2, ..., m} called the ground set. The objective function f :F→ ...

High School Timetabling (HSTT) is a well known and wide spread problem. The problem consists of coordinating resources (e.g. teachers, rooms), times, and events (e.g. lectures) with respect to various constraints. Unfortunately, HSTT is hard to solve and just finding a feasible solution for simple variants of HSTT have been proven to be NPcomplete. We propose a new algorithm for HSTT which comb...

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The recent increase in online orders e-commerce leads to logistical challenges such as low hit rates (proportion of successful deliveries). We consider last-mile vehicle routing and scheduling problems which customer presence probability data are taken into account. aim is reduce the expected cost resulting from by considering both decisions simultaneously planning phase. model problem solve it...

The p-Center problem consists of locating p facilities and assigning clients to them in order to minimize the maximum distance between a client and the facility to which he or she is allocated. In this paper, we present a basic Variable Neighborhood Search and two Tabu Search heuristics for the p-Center problem without the triangle inequality. Both proposed methods use the 1-interchange (or ver...