In this paper we propose a heuristic algorithm to solve the Vehicle Routing Problem with Time Windows. Its framework is a smart combination of three simple procedures: the classical k-opt exchanges improve the solution, an ad hoc procedure reduces the number of vehicles and a second objective function drives the search out of local optima. No parameter tuning is required and no random choice is...

The article describes an investigation of the effectiveness of genetic algorithms for multi-objective combinatorial optimization (MOCO) by presenting an application for the vehicle routing problem with soft time windows. The work is motivated by the question, if and how the problem structure influences the effectiveness of different configurations of the genetic algorithm. Computational results...

Many practical problems arising in real world applications, mainly in the fields of logistics and telecommunications, can be modeled as network design or vehicle routing problems. In this thesis we study three combinatorial optimization problems belonging to the classes of Network Design and Vehicle Routing problems that are strongly linked in the context of the design and management of transpo...

This paper introduces a new algorithm, based on the concept of ejection chains, to effectively target vehicle routing problems with time window constraints (VRPTW). Ejection chains create powerful compound moves within Local Search algorithms. Their potential to yield state of the art algorithms has been validated for the traveling salesman problem (TSP), for example. We show how ejection chain...

We consider a variant of the vehicle routing problems with time windows, where the objective includes the inconvenience cost modeled by a convex function on each node. We formulate this mixed integer convex program using a novel set partitioning formulation, by considering all combinations of routes and block structures over the routes. We apply a branch-and-price framework to solve this formul...

The Vehicle Routing Problem with Time Windows (VRPTW) is an important problem in logistics, which is an extension of well known Vehicle Routing Problem (VRP), with a central depot. The Objective is to design an optimal set of routes for serving a number of customers without violating the customer’s time window constraints and vehicle capacity constraint. It has received considerable attention i...

In the context of information technology, efficient and reliable logistics are a key factor for the economic success of online shops, This necessarily requires an effective way to plan goods delivery to improve efficient and speed, the most important and widely studied combinatorial optimization problems, which continue to draw attention from researchers is the vehicle routing problem, which ca...

The vehicle routing problem with backhauls and time windows (VRPBTW) involves the pickup and delivery of goods at different customer locations, with earliest and latest time deadlines, and varying demands. The demands are serviced using capacitated vehicles with limited route time. Moreover, all deliveries (linehauls) must be done before the pick-ups (backhauls). The objective of the problem is...

In this paper we introduce a new formulation of the VRPTW involving only binary variables associated with the arcs in the underlying digraph. The new formulation is based on the formulation of the ATSPTW by Ascheuer et al. [1] and has the advantage of avoiding additional variables and linking constraints. In the new formulation of the VRPTW time windows are modeled using path inequalities. The ...