Title
Cover Inequalities for a Vehicle Routing Problem with Time Windows and Shifts
Abstract
AbstractThis paper introduces the vehicle routing problem with time windows and shifts (VRPTWS). At the depot, several shifts with nonoverlapping operating periods are available to load the planned trucks. Each shift has a limited loading capacity. We solve the VRPTWS exactly by a branch-and-cut-and-price algorithm. The master problem is a set partitioning with an additional constraint for every shift. Each constraint requires the total quantity loaded in a shift to be less than its loading capacity. For every shift, a pricing subproblem is solved by a label-setting algorithm. Shift capacity constraints define knapsack inequalities; hence we use valid inequalities inspired from knapsack inequalities to strengthen the linear programming relaxation of the master problem when solved by column generation. In particular, we use a family of tailored robust cover inequalities and a family of new nonrobust cover inequalities. Numerical results show that nonrobust cover inequalities significantly improve the algorithm.
Year
DOI
Venue
2019
10.1287/trsc.2018.0885
Periodicals
Keywords
Field
DocType
vehicle routing problem,column generation,shift capacity,branch-and-cut-and-price algorithm
Truck,Column generation,Mathematical optimization,Vehicle routing problem,Inequality,Mathematics
Journal
Volume
Issue
ISSN
53
5
1526-5447
Citations 
PageRank 
References 
0
0.34
0
Authors
3
Name
Order
Citations
PageRank
Said Dabia1314.11
Stefan Ropke2134755.90
eu354939.51