Optimization On Vehicle Routing Problems With Simultaneous Pickup And Delivery Under Customers' Demand Overlapped

In the current declining economy,many private small and medium enterprises are forced to cut costs to increase profit and enhance self-competitiveness.Meanwhile,delivery cost takes up a large portion in the cost structure.Based on various research,China is still experiencing many problems in delivery services including insufficient route planning,repetitiveness and inefficiency,and high reliance on experience in organizing capacity and arranging delivery routes.These problems cause overlaps and roundabouts in delivery process.We believe scientifically choosing reasonable distribution line is the most effective way so as to boost delivery speed,reduce transportation costs,increase profit and improve self-competitiveness.In the traditional logistics model,package delivery companies react to delivery needs by sending vehicle to either deliver or pickup,but not both,resulting in empty loaded vehicle.The widespread need to increase vehicle utilization and lower delivery costs lead to the concept of simultaneous pickup and delivery,which means the delivery services will not only deliver to clients,but also collect certain goods from customers for return.However,the present research on simultaneous delivery and pickup mainly focuses on fulfilling delivery needs and then transporting return goods back to depot center.This article,on the other hand,devotes its effort to disregard the actual need of clients requesting returns but consider collecting certain return goods that can be resold;in this case,the collected goods can be transported to other customers who are in need of the merchandise.This model will eventually eliminate the cost of having to send the return goods back to depot center,and achieve optimal logistics through VRP.This essay studies VRPSPD in the event of demand overlap,establishes the most cost effective mathematical model,and utilizes genetic algorithm to solve the model,and in the mean time designs specific examples to prove the feasibility and effectiveness of the established model.