Title
Vehicle routing problem with fuzzy time windows
Abstract
In this paper, a vehicle routing problem with fuzzy time windows (VRPFTW) is proposed and solved. In the transportation business, time windows are not always strictly obeyed and the deviation of service time from the customer-specific time window determines the customer's satisfaction level, which can also be regarded as the supplier's service level. This paper applies fuzzy membership functions to characterize the service level issues associated with time window violation in a vehicle routing problem and proposes VRPFTW. VRPFTW is formulated as a multi-objective model with two goals: (1) to minimize the travel distance and (2) to maximize the service level of the supplier to customers. To solve this multi-objective model, a two-stage algorithm is developed to obtain a Pareto solution for VRPFTW. Using the two-stage algorithm, VRPFTW is decomposed into two subproblems, namely a traditional vehicle routing problem with time windows (VRPTW-@a) and a service improvement problem, and each of the objectives is sequentially solved. The service improvement problem is solved under two different scenarios. When the fuzzy membership function is linear, it is shown that the service improvement problem can be solved by the cutting plane algorithm within finite iterations, and when the fuzzy membership function is concave, the service improvement problem can be solved by a subgradient-based algorithm. Moreover, an alternative formulation of VRPFTW is also proposed and analyzed. Experiments are conducted to compare different models of vehicle routing problems with time windows in situations where violation of time windows is allowed, and the results show that the VRPFTW model can achieve considerable cost-savings, while at the same time maintaining an acceptable service level.
Year
DOI
Venue
2009
10.1016/j.fss.2008.09.016
Fuzzy Sets and Systems
Keywords
Field
DocType
service level issue,customer-specific time window,multi-objective model,fuzzy membership function,service level,time windows,acceptable service level,service improvement problem,fuzzy time windows,two-stage algorithm,object model,vehicle routing problem
Vehicle routing problem,Mathematical optimization,Information processing,Service level,Subgradient method,Fuzzy logic,Concave function,Fuzzy set,Fuzzy control system,Mathematics
Journal
Volume
Issue
ISSN
160
5
Fuzzy Sets and Systems
Citations 
PageRank 
References 
29
0.94
7
Authors
4
Name
Order
Citations
PageRank
Jiafu Tang154149.29
Zhendong Pan2532.52
Richard Y. K. Fung344435.21
Henry Lau4737.60