Study on the Inventory Routing Problem of Refined Oil Distribution Based on Working Time Equilibrium

Taking the distribution route optimization of refined oil as background, this paper studies the inventory routing problem of refined oil distribution based on working time equilibrium. In consideration of the constraints of vehicle capacity, time window for unloading oil, service time and demand of each gas station, we take the working time equilibrium of each vehicle as goal and establish an integer programming model for the vehicle routing problem of refined oil distribution, the objective function of the model is to minimize the maximum working time of vehicles. To solve this model, a Lingo program was written and a heuristic algorithm was designed. We further use the random generation method to produce an example with 10 gas stations. The local optimal solution and approximate optimal solution are obtained by using Lingo software and heuristic algorithm respectively. By comparing the approximate optimal solution obtained by heuristic algorithm with the local optimal solution obtained by Lingo software, the feasibility of the model and the effectiveness of the heuristic algorithm are verified. The results of this paper provide a theoretical basis for the scheduling department to formulate the oil distribution plan.

An evolutionary algorithm approach for the constrained multi-depot vehicle routing problem

Purpose-The purpose of this paper is to explore a real world vehicle routing problem(VRP)that has multi-depot subcontractors with a heterogeneous fleet of vehicles that are available to pickup/deliver jobs with varying time windows and locations.Both the overall job completion time and number of drivers utilized are analyzed for the automated job allocations and manual job assignments from transportation field experts.Design/methodology/approach-A nested genetic algorithm(GA)is used to automate the job allocation process and minimize the overall time to deliver all jobs,while utilizing the fewest number of drivers-as a secondary objective.Findings-Three different real world data sets were used to compare the results of the GA vs transportation field experts’manual assignments.The job assignments from the GA improved the overall job completion time in 100 percent(30/30)of the cases and maintained the same or fewer drivers as BS Logistics(BSL)in 47 percent(14/30)of the cases.Originality/value-This paperprovidesa novel approach to solving a real world VRPthathasmultiple variants.While there have been numerous models to capture a select number of these variants,the value of this nested GA lies in its ability to incorporate multiple depots,a heterogeneous fleet of vehicles as well as varying pickup times,pickup locations,delivery times and delivery locations for each job into a single model.Existing research does not provide models to collectively address all of these variants.