The Multi-Level Bidirectional Logistics Network Planning Of Remote Sea Islands And Reefs Group

In an environment where the current international situation is complex,marine fisheries and energy resources are being plundered,and the safety of shipping corridors is facing the challenge of embarrassment,.with the completion of the artificial reclamation of the remote sea islands and reefs group in China,in order to ensure the smooth flow of human life and production materials on the islands and reefs,it is urgent to plan to establish a kind of Multi-level bidirectional logistics transportation network system that integrates various factors such as site selection of transit islands and reefs,transportation route and inventory control planing.This paper studies the optimization of multi-level bidirectional logistics network planning for maritime transport with the remote sea islands and reefs group as the background,its innovations are:the transportation route is set to two types,such as,round-trip route and cycle route,the thesis insists on the implementation of "big ship transporting big island,small ship transporting small island",the flight parameters of each island reef are configured by parallel search for the upper and lower transport networks to achieve the goal of minimizing costs while successfully completing transportation tasks.The thesis focuses on the following four areas:Firstly,the paper outlines the background,research purpose and significance of the thesis,reviews both the domestic and foreign status of research from the aspects of logistics network construction and optimization,route distribution and transportation,land and island traffic situation,political issues in the South China Sea,the contents and methods of related research are expounded in the aspects of regional logistics,hub pivot shaft spoke logistics network,reverse logistics network,so it can provide theoretical support for this study;Secondly,according to the geographical and climatic environment of the islands and reefs group,and the material demand and output of the islands and reefs group,and the characteristics of the islands and reefs group logistics system were analyzed,expounds the design principles of the hub site selection system,the shipping route transportation system and the warehouse storage system of the islands and reefs group maritime logistics network,considering factors such as ship acquisition and operation costs,terminal construction costs,and storage system operating costs,a MLIRP joint optimization model for overall planning under the background of ocean transportation is established;Thirdly,according to the characteristics of the model,a double gradation parallel search genetic algorithm is proposed to solve the problem;Finally,taking Xisha Islands,Dongsha Islands and Nansha Islands in the South China Sea as examples,the marine logistics network system of reef group is established,setting the parameters of daily average material supply,product return volume,tonnage of alternative ship type,various related costs,operating accounting period,safe stock time and so on for each reef in the system,according to different scales of the problem,the results,stability of the results,computing times and memory occupancy are compared with genetic algorithm respectively to verify the feasibility and rationality of the model and algorithm.The contents and methods of this paper are essentially different from those of the previous LIRP problems,which mainly focus on land transportation,therefore,this method and content enrich the application scenarios of LIRP joint optimization problem,provide reference for the further study of logistics transportation network system under more complex and changeable conditions,and have important theoretical significance and practical value for the development and construction of the South China Sea.The innovative results of this research mainly include the following:(1)Constructed a joint optimization logistics network system that comprehensively considers "location-inventory-routing",a MLIRP joint optimization model for overall planning under the background of ocean transportation is established.(2)A two-layer parallel search genetic algorithm suitable for solving the problem is proposed to solve the problem,which effectively avoids the disadvantages of the upper-layer network search in the process of lower-layer network search.(3)Taking the actual situation of Paracel Islands,Dongsha Islands and Nansha Islands in the South China Sea as an example,and comparing the results of this paper with the genetic algorithm according to different scale problems respectively to verify the feasibility and rationality of the model and algorithm.