Research On The Distribution Route Optimization In Time-constrained Pharmaceutical Logistics

As an important part of the national economy,the pharmaceutical industry is also a key area of national security.In recent years,with the promotion of the market economy and the promotion of policies,the pharmaceutical industry in China has developed rapidly,and pharmaceutical logistics enterprises are facing great opportunities.However,with the gradual release of the medical field in China,a large number of foreign pharmaceutical logistics enterprises are bound to participate in the domestic competition.Because China's pharmaceutical logistics system is still in its growth stage,small profit margins,high operating costs and poor service quality will seriously restrict the development of Chinese pharmaceutical logistics enterprises.It is difficult to cope with the fierce international competition,and it is urgent to develop a high-efficiency and high-quality medical logistics system.Path selection of distribution vehicles is an important aspect of pharmaceutical logistics system.This paper is aimed at the research on the optimization of vehicle routing in pharmaceutical logistics,which has certain guiding significance and realistic value.Includes:reduce distribution cost,pharmaceutical logistics enterprises obtain more "third profit source",improve customer satisfaction,increase customer dependence for logistics enterprises.Reduce the number of delivery vehicles and vehicle distribution path distance,ease traffic pressure,reduce vehicle exhaust emissions.Enhance the competitiveness of our pharmaceutical logistics enterprises in the international competition to ensure the safety of national pharmaceutical industry.First of all,this paper makes the research on the vehicle routing problem and pharmaceutical logistics.At the same time,analyzes the connotation and characteristics of the pharmaceutical logistics,as well as the connotation of the vehicle routing problem,the classification and solution.Secondly,we introduce the time window in detail and gives three kind of punishment function under the soft time window,which are the linear penalty function,quadratic penalty function and sigmoid penalty function and convert customer satisfaction into penalty cost function,establish a basic model of vehicle routing problem minimized by distribution cost and establish a multi-objective two-way VRPSTW vehicle scheduling model by considering the daily different needs and the two-way satisfaction between the enterprise and the customer.The objective of the model is to minimize the cost of transport and vehicles,and choose different transport routes and strategies according to different freight transport distribution and punishment rules to maximize the satisfaction of both parties.After that,the basic idea and working mechanism of the saving mileage algorithm are introduced and the saving mileage algorithm of time window constraint is designed,meanwhile,the saved mileage algorithm of the time window is applied in the transportation of different penalty functions.Finally,analyze the pharmaceutical logistics enterprises in three provinces,namely shandong province,anhui province and henan province,and verifies the validity of the model,penalty function and the algorithm.