Construction And Optimization Of Cold Chain Logistics Network Of Offshore Fisheries

With the increasing competition for marine resource in the recent years,the Chinese government has put forward some policies such as " develop fishery as the first thing for the Nansha Islands" and "station fishery industry to garrison the border".Therefore,it should take the waters of Nansha Islands as an important space for the development of offshore fisheries.Building a complete fishery cold chain logistics network system in the area is of great significance for safeguarding China’s marine rights and interests.However,there has been still a lack of theoretical analysis on the concept theory and operation mode of the cold chain logistics network of offshore fisheries in the existing literature.Also,there has few effective modeling methodology in order to develop its network construction and optimization problem.The above problems have a direct impact on the in-depth development of the theory and practice of the cold chain logistics network of offshore fisheries.Therefore,this thesis took the waters of the Nansha Islands in China as the application background and analyzed the characteristics of the cold chain logistics of offshore fisheries.Then,we comprehensively used the data of fishery resource survey,geographic information technology and bioeconomic yield model to realize the quantitative assessment of the fishery resources in the study area.On this basis,the layout of fishing grounds and the location scheme of transit cold storage were determined by taking into account the catch and total operating cost of cold chain system.The operation plan of inventory and routing of transit cold storage after the location was discussed in combination with seasonal scenarios.The construction and optimization of offshore fishery cold chain logistics network were studied step by step.The main research work carried out and completed in this thesis is as follows:Firstly,carry out the research on the characteristics of the cold chain logistics of offshore fisheries.This section summarized the basic composition of the cold chain logistics network of offshore fisheries,including fishing grounds,transit cold stores,mainland fishing ports and their turnaround shipping routes.Specifically,this section described each node and its the operation process of each node,the setting of routes and the characteristics of ship allocation.On this basis,it summarized the two modes of direct transportation and transit that could be selected for offshore fishing catch transportation,and introduced the current situation and existing problems of the Nansha fishery production in China.This section lays a foundation for the research on the construction and optimization of cold chain logistics network.Secondly,carry out quantitative assessment and analysis research on fishery production in the open sea.Taking the actual situation of fishery resources as the starting point,the survey data of fishery resources was analyzed by using GIS technology,and a database was established to explore the quantity of fishery resources and migration laws,revealing the spatial distribution and seasonal variation characteristics of fishery resources.On this basis,an assessment model adapted to the characteristics and data status of fish in Nansha was used to quantify its catch,and the candidate location of fishing ground was analyzed accordingly.This section not only effectively provides a technical basis for the quantitative analysis of the catch volume and operation location of the fishery cold chain,but also helps to increase the scientific nature of the construction of the cold chain logistics network.Thirdly,carry out the research on the layout of fishery production areas and the location optimization of transfer cold storage.By analyzing the relationship between the layout of fishing grounds and the location of transfer cold storage,the two transportation organization modes of direct transportation from sea to the mainland and the transfer of island cold storage were considered in this section.An optimization model with the maximum catch and the minimum total operating cost of the cold chain system was established.When solving,the traditional NSGA-II was improved by embedding chaotic sequences into the crossover and mutation operations,repairing the infeasible solutions based on the removal strategy of greedy algorithm,and improving the fast dominance strength sorting,congestion distance and elite retention strategy to improve the algorithm performance.Finally,the implementation plan of the Nansha fishery production activities and the construction of the transfer cold storage was optimized.The Pareto non-inferior solution was selected by analyzing the basic principles of the decision makers to select the optimal plan,and the final optimization plan was determined,which verified the feasibility and effectiveness of the model and algorithm.This section could enrich the location optimization model and algorithm of cold-chain storage facilities based on maritime transportation,and provides a new idea for the layout of distant sea fishing grounds and the location optimization of transfer cold storage.Finally,carry out the research on the optimization of transportation problem of transit cold storage in the offshore islands.Combined with the seasonal fluctuation of the storage in the transit cold storage,a dynamic ship picking strategy with the unfixed route and unfixed transportation batch was proposed.With the goal of minimizing the total cost of inventory,transportation and perishable damage in the total planning period,a optimization model for the maritime inventory and routing of the transit cold storage was constructed.Base on the characteristics of the proposed model,a two-stage heuristic algorithm was designed,which combines the rolling horizon planning method with the improved variable neighborhood search algorithm.The feasibility and effectiveness of the model and algorithm were verified by the example of catch transportation after the construction of cold storage in the Nansha Islands,and the impact of different cost parameters on the optimization results was discussed by sensitivity analysis.This section further explores the connection and operation mechanism between the transit cold storage and the mainland fishing port nodes,which could be helpful to increase the flexibility of inventory control and routing design.The results of this thesis enrich the optimization theory and methods for the effective organization and management of the cold chain activities of offshore fisheries.It could provide a new idea for the construction of the integrated fishery production system of offshore fishing,fresh harvesting,storage and transportation,and so on.What’s more,it could have important practical value for the establishment of the the Nansha Islands fishery production cold chain logistics network.