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Mingyong L.,Hunan University | Mingyong L.,Hunan Province Laboratory of Logistics Information and Simulation Technology | Erbao C.,Hunan University | Erbao C.,Hunan Province Laboratory of Logistics Information and Simulation Technology
Engineering Applications of Artificial Intelligence | Year: 2010

The vehicle routing problem with simultaneous pickups and deliveries and time windows (VRP-SPDTW) is the problem of optimally integrating forward (good distribution) and reverse logistics (returning materials) for cost saving and environmental protection. We constructed a general mixed integer programming model of VRP-SPDTW. The model contained some classical vehicle routing problems as special cases. We proposed an improved differential evolution algorithm (IDE) for solving this problem. In the algorithm, we firstly adopted the novel decimal coding to construct an initial population, then used some improved differential evolution operators unlike the existing algorithm, and in mutation operation, we used an integer order criterion based on natural number coding method. We 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. We did some numerical experiments, and the results showed that the proposed method is effective for solving VRP-SPDTW. Crown Copyright © 2009. Source


Cao E.-B.,Hunan University | Cao E.-B.,Hunan Province Laboratory of Logistics Information and Simulation Technology | Lai M.-Y.,Hunan University | Lai M.-Y.,Hunan Province Laboratory of Logistics Information and Simulation Technology
Xitong Gongcheng Lilun yu Shijian/System Engineering Theory and Practice | Year: 2010

The coordination problem of a supply chain with one supplier and n Bertrand competing retailers was analyzed. It was proved that a revenue sharing contract can be used to coordinate the supply chain under normal environment. But the coordination may be broken off by demand scale and cost disruptions, and the optimal strategies that the centralized decision-making supply chain replied to the disruptions were proposed by solving the Kuhn-Tucker (KT) condition of optimal profit of supply chain system under disruptions. It was further proved that an improved revenue sharing contract can be used to coordinate the decentralized decision-making supply chain when demands and costs were disrupted simultaneously. Finally, a numerical example was presented to illustrate the efficiency of the proposed model. Source


Cao E.,Hunan University | Cao E.,Hunan Province Laboratory of Logistics Information and Simulation Technology | Lai M.,Hunan University | Lai M.,Hunan Province Laboratory of Logistics Information and Simulation Technology | Yang H.,Changsha University of Science and Technology
Expert Systems with Applications | Year: 2014

We investigate the open vehicle routing problem with uncertain demands, where the vehicles do not necessarily return to their original locations after delivering goods to customers. We firstly describe the customer's demand as specific bounded uncertainty sets with expected demand value and nominal value, and propose the robust optimization model that aim at minimizing transportation costs and unsatisfied demands in the specific bounded uncertainty sets. We propose four robust strategies to cope with the uncertain demand and an improved differential evolution algorithm (IDE) to solve the robust optimization model. Then we analyze the performance of four different robust strategies by considering the extra costs and unmet demand. Finally, the computational experiments indicate that the robust optimization greatly avoid unmet demand while incurring a small extra cost and the optimal return strategy is the best strategy by balancing the trade-off the cost and unmet demand among different robust strategies. © 2013 Elsevier B.V. All rights reserved. Source


Cao E.,Hunan University | Cao E.,Hunan Province Laboratory of Logistics Information and Simulation Technology | Ma Y.,Hunan University | Ma Y.,Hunan Province Laboratory of Logistics Information and Simulation Technology | And 3 more authors.
Operations Research Letters | Year: 2013

The optimal wholesale contract design problem is modeled in a dual-channel supply chain under information asymmetry. We consider the games with asymmetric cost information and full information respectively, derive the corresponding equilibrium strategies and profits, and conduct detailed comparisons and analyses. We investigate the impact of asymmetric cost information on the equilibrium strategies and profits of partners in the supply chain and analyze the values of the cost information from the perspectives of the partners and the whole system respectively. © Copyright 2013 Published by Elsevier B.V. All rights reserved. Source


Nie K.,Hunan University | Nie K.,Hunan Province Laboratory of Logistics Information and Simulation Technology | Lai M.,Hunan University | Lai M.,Hunan Province Laboratory of Logistics Information and Simulation Technology | And 4 more authors.
Applied Mechanics and Materials | Year: 2010

With the rapid growing of domestic rural market, it is important to develop rural logistics system. Up to now, the general two-direction logistics mode was investigated in order to achieve high efficiency. However the mode was still based on qualitative analysis. This paper proposed a novel rural two-direction logistics system model based on SPN theories. By utilizing the mathematic characteristics of SPN, quantitative parameters of the model were deduced. Finally, compared with the general logistics mode, the proposed logistics mode can improve the logistics efficiency. © (2010) Trans Tech Publications. Source

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