Kewei Chen

Solving Truck Delivery Problems Using Integrated Evaluation Criteria Based on Neighborhood Degree and Evolutionary Algorithm

To solve a real-world truck delivery and dispatch problem (TDDP) that involves multiple mutually conflicting objectives, such as running and loading costs, a concept of neighborhood degree (ND) and an integrated evaluation criteria (IEC) of the solution based on ND are proposed. The IEC makes the weight setting easier than by using conventional methods. To find a high-quality solution to a TDDP in practical computational time, an evolutionary algorithm is proposed. It involves 3 components: (i) a simulated annealing (SA)-based method for finding an optimal or a suboptimal route for each vehicle; (ii) an evolutionary computation (EC)-based method for finding an optimal schedule for a group of vehicles; and (iii) threshold-based evolutionary operations, utilizing the ND concept. The TDDP viewed from real-world application is formulated and the proposed algorithm is implemented on a personal computer using C++. The proposed algorithm is evaluated in 2 experiments involving real-world data representative of the TDDP, and applied to food product delivery to a chain of 46 convenience stores in Saitama Prefecture. In the 2 experiments, our proposed algorithm resulted in a better schedule (with 80%-90% shorter computational time) than a schedule produced by an expert. By incorporating application-specific evaluation criteria, the proposed algorithm is applied to problems such as homedelivery of parcels or mail, and to problems of multidepot delivery and dispatch.

Vehicle Routing, Scheduling and Dispatching System Based on HIMS Model

A concept of the VRSDP/SD problem and its formularization are proposed in order to bridge the gap between conventional methods and complex situations in the real world. A HIMS model is also proposed for the VRSDP/SD problem. Experiments with two cases (full or partial working), are performed. The experimental results and the evaluations by experts from practice show that the HIMS model provides a feasible, fast, and efficient tool for the real world problem.

A solution for delivery problem based on HIMS model and service science

A solution for the delivery problem (vehicle routing, scheduling, and dispatching problem with single depot) is proposed to bridge the gap between conventional methods and complex situations in the real world. The HIMS model (a computational model with Hierarchical Multiplex Structure) is also applied for solving the delivery problem. The HIMS model contains 3 layers: Atomic layer (system cost can be controlled by a heuristic method), Molecular layer (system state can be adjusted by a heuristic method and an optimal calculation), and Individual layer (a system balance can be modified based on information technology service). Experiments with two cases (full or minimum working vehicles) are performed. The experimental results and the evaluations by experts show that the solution provides a feasible and efficient tool to solve the delivery problem in the real world.

Fuzzy Neighborhood Based Approach for Practical Delivery Problem

A solving method is proposed for the practical delivery problem by truck. In order to make easier the weight setting for each of the evaluation criteria presented in the evaluation function, an integrated evaluation criterion is proposed based on fuzzy neighborhood degree concept. Furthermore, with the objective to obtain a high-quality solution in short computational time, (i) a simulated annealing based method for finding a (sub-)optimal route for each vehicle; and (ii) an evolutionary computation based method for finding a (sub-)optimal schedule for a group of vehicles are proposed. The proposed method is implemented in C++ language on a personal computer, and is evaluated on real-world data from a food company in Saitama prefecture, Japan. Compared to a scheduling expert, the proposed method has resulted in 18% lower delivery cost, with 80%-90% shorter computational time. The proposed methods is able to also be applied to other delivery problem such as home delivery services and mail delivery problems.