the capacitated location-routing problem (clrp) is a new research area in logistics and distribution management. this problem combines two difficult problems: the facility location problem (flp) and vehicle routing problem (vrp). the goal of the clrp is to open a subset of depots, assign the customers into open facilities, and then design vehicle tours in order to minimize the total cost. the t...

In this paper we present a computational study on 112 instances of the workforce scheduling and routing problem (WSRP). This problem has applications in many service provider industries where employees are required to visit customers to perform certain activities. Given their similarity, we adapt a mathematical programming model from the literature on vehicle routing problem with time windows (...

The Vehicle Routing Problem with Time Windows (VRPTW) is a complex combinatorial optimisation problem which can be seen as a combination of two well-known sub-problems: the Travelling Salesman Problem and the Bin Packing Problem. Relevant objectives include minimising the number of vehicles and the total travelling distance for delivering demand to customers, while complying with capacity and t...

This paper introduces a variant of the vehicle routing problem with time windows where a limited number of vehicles is given (m-VRPTW). Under this scenario, a feasible solution is one that may contain either unserved customers and/or relaxed time windows. We provide a computable upper bound to the problem. To solve the problem, we propose a tabu search approach characterized by a holding list a...

The Vehicle Routing Problem with Time Windows (VRPTW) is currently the focus of very intensive research, and is used to model many realistic applications. The overall objective is to serve a set of customers at minimum cost with a fleet of vehicles of finite capacity housed at a central depot. The route of each vehicle starts and ends at the depot. Also, each customer has a known demand (i.e. s...

Considering the vehicle routing problem with fuzzy demand and time windows, a optimization method is proposed considering both soft windows uncertain customer demand. First, chance-constrained programming model established based on credibility theory, minimizing total logistics cost. At same time, random simulation algorithm designed to calculate penalty cost of delivery failures caused by that...

We study a new variant of the well-studied vehicle routing problem with time windows (VRPTW), called fragility-constrained VRPTW, which assumes that (1) capacity is organized in multiple identical stacks; (2) all items picked up at customer are either “fragile” or not; (3) no nonfragile can be put on top fragile item (the fragility constraint); and (4) en route load rearrangement possible. firs...

The vehicle routing problem with time windows (VRPTW) is an extension of the well-known vehicle routing problem with a central depot. The objective function of the VRPTW considered here combines the minimization of the number of vehicles (primary criterion) and the total travel distance (secondary criterion). In this paper, a two-phase procedural approach for solving the VRPTW is parallelized. ...

This work presents an exact branch-cut-and-price (BCP) algorithm for the vehicle routing problem with time windows (VRPTW) where the well-known clique inequalities are used as cutting planes defined on the set partitioning master problem variables. It is shown how these cutting planes affect the dominance criterion applied in the pricing algorithm, which is a labeling algorithm for solving the ...

Industrial growth and expanding employment opportunities have led to the urban-oriented economic development in many countries. Demand of transportation, both in terms of passengers as well as for freight is also increasing in and around these big urban conurbations. A high proportion of total goods movement occurs within cities 1) , and most of this movement is based on road transport. Traffic...