Chen D.,Hunan University |
Chen D.,Hunan Province Key Laboratory of Logistics Information and Simulation Technology |
Cao E.,Hunan University |
Cao E.,Hunan Province Key Laboratory of Logistics Information and Simulation Technology
Journal of Intelligent and Fuzzy Systems | Year: 2016
In this paper, a pickups and deliveries problem with fuzzy time windows (PDPFTW) is presented and solved. The customer service level associated with time window is characterized by fuzzy membership functions based on fuzzy set theory. A novel multi-objective fuzzy programming model of PDPFTW is proposed. The proposed model aims at minimizing the vehicle numbers and the overall travel costs and maximizing the total customer service level. A novel differential evolution algorithm (DE) for PDPFTW is also proposed. In DE, we first adopted the novel decimal coding to construct an initial population, and then used some improved differential evolution operators unlike existing algorithm, in mutation operation, we used an integer order criterion based on natural number coding method and introduced a penalty technical to publish the infeasible solution. In addition, in the crossover operation, we designed a self-adapting crossover probability that varied with iteration. Our experimental results demonstrate the efficiency of the proposed DE, which saved some running time compare with GA in 100,200,400 and 1000 cases. At the same time, DE can get better solutions compare with GA in total distance of vehicles, total services level of customers and vehicle numbers. Moreover, we found that total service level would increase with wider time window. © 2016 - IOS Press and the authors. All rights reserved.
Cao E.,Hunan University |
Cao E.,Hunan Province Key Laboratory of Logistics Information and Simulation Technology |
Wan C.,Hong Kong Polytechnic University |
Lai M.,Hunan University |
Lai M.,Hunan Province Key Laboratory of Logistics Information and Simulation Technology
International Journal of Production Economics | Year: 2013
This paper develops a coordination mechanism for a supply chain consisting of one manufacturer and n Cournot competing retailers when the production cost and demands are simultaneously disrupted. This differs from traditional supply chain coordination models under a static case and the case with only demand or cost disruption. The coordination mechanism with revenue sharing is considered, and the effects of production cost and demand disruptions on revenue sharing contract are discussed to investigate the optimal strategies of players with disruptions. The penalty cost is introduced explicitly to obtain the production deviation cost caused by the disruptions. In this study, it is obtained that the coordination contract considering the production deviation cost differs from that without disruption. Besides that, the disruptions may affect the order quantities, wholesale prices as well as revenue sharing contract. Then, the optimal strategies for different disruption levels under the centralized decision-making mode are proposed. Concerning the decentralized mode, the improved revenue sharing contract can be used to coordinate the decentralized decision-making supply chain effectively. Finally, the theoretical results are illustrated by conducting some numerical examples. © 2012 Elsevier B.V. All rights reserved.