Research On Network Design And Optimization Of Fourth Party Logistics System With Reliability Requirement

The fourth party logistics(4PL) system carries high levels of complexity and uncertainty. The external environmental disturbance causes the decline of the logistics service level and network disruption. This type of risk can bring a huge economic loss to the corporation. Therefore, the security and reliability of the 4PL system is crucial. However, the design and optimization of the 4PL system network is a NP-hard problem. Considering the reliability with probability character in the process of optimization is a complicated course. After the fusion, the complexity of the model will rise significantly. This dissertation makes a systematic analysis on the difficulties and character of the problem. We apply theories and approaches such as operations research, reliability and intelligence optimization algorithm to investigate the measurement to the reliability of the 4PL system. The model of the 4PL system network design and optimization with reliability requirement is established. According to the complexity of the model, the corresponding intelligence optimization algorithm is proposed to solve the model. The main contents of the dissertation are as follows:(1) Research on routing optimization of single source to single sink fourth party logistics considering time reliability constraint. Reliability theory is applied to routing optimization problem. A mathematical model of the 4PL routing optimization problem considering time reliability constraint is built, which aims to find a route at the minimum cost. According to the characteristics of the model, a Messy Genetic Algorithm(Messy GA) with double arrays encoding method is designed. Experimental results show that the Messy GA can provide the optimal solution to decision-makers quickly and effectively, according to customer’s time reliability requirements.(2) Research on routing optimization of multi-source to multi-sink fourth party logistics with reliability constraint. The 4PL provider need to allocate resources worldwide and udertake transport task in different areas. The routing optimization of multi-source to multi-sink and multi-task fourth party logistics is studied. The mathematical model of the multi-source to multi-sink 4PL routing optimization with reliability constraint is set up. An intelligence optimization algorithm is designed to solve the model. The effectiveness of the algorithm and model is tested by simulation examples.(3) Research on single-period network design with disruption risk consideration of the 4PL. The target is to construct a 4PL network that can provide satisfactory service to customers with a lower cost when disruptions strike. A robust optimization model of 4PL network design with disruption risk consideration is developed. For the NP-hard characteristic of the problem, the Artificial Fish Swarm Algorithm(AFSA) with changeable length natural number encoding strategy base on multi-dimensions spaces and the Genetic Algorithm(GA) are developed. The effectiveness of the algorithms is tested and compared by simulation examples. By comparing the optimal solutions of the 4PL network for different robustness level, it is indicated that the robust optimization model can evade the market risks effectively and save the cost in the maximum limit when it is applied to 4PL network design.(4) Research on multi-period dynamic optimal network design of the 4PL with reliability requirement. In order to make the 4PL network satisfy customer requirements under disruptions in each period, the reliability of the 4PL network is defined as the satisfaction rate of the demand nodes. A mathematical model is formulated, which maximizes the reliability of the 4PL system subjective to investment cost. Based on the NP-hard characteristic of the problem, the Krill Herd Algorithm(KHA) and Artificial Fish Swarm Algorithm(AFSA) are presented and the performance of the algorithm is tested by simulation examples. According to the simulation results, the KHA performs better in effectiveness and stability than the AFSA. Decision makers can invest in redundant resources to improve the reliability of the 4PL network considering the investment cost constraint.This dissertation prosents several methods for the network design and optimization of the fourth party logistics system based on reliability, aiming at sovling the problem of the effects of uncertain factors on the logistics service quality with disruptions in reality. Under the condition of the uncertain environments and the limited cost, the beneficial decision-making references to the resources utilization of validity and the reduction of logistics cost are proposed.