A Research Of The Space Scheduling Of Coal Stockyard Based On The Two-dimensional Strip Packing Problem

Coal is the main energy used in China today,and it will occupy a dominant position in China’s energy structure for a certain period of time.As coal is transported from the mine to the customer,the port,as an important hub connecting upstream and downstream,is an important link in the coal supply chain.The stockyard is the buffer zone of coal transshipment in the port,and its turnover speed directly affects the overall operating efficiency of the port.Due to the limitation and unexpandability of the stockyard space,the stockyard operation is often the bottleneck that restricts the efficiency of port.Therefore,it is of great significance in reality to reasonably dispatch the space resource of the coal stockyard to improve the operating efficiency of the stockyard and the competitiveness of the port.In the existing literature on coal stockyard space scheduling,most of the research objects are the stockyard space scheduling problem under the static fixed stacking mode,and the simulation method is the main method;In the few researches on the stockyard space scheduling problem under the dynamic open stacking mode,the data scale of the problem solved by the exact algorithm is limited,so the problem of the real application scale data cannot be solved.In this paper,starting from the dynamic open stacking mode of the stockyard space,based on the Bottom Left algorithm,constraint programming,and greedy random adaptive search procedure algorithm for solving the two-dimensional strip packing problem,a study on the space scheduling of coal stockyard based on the twodimensional strip packing problem is presented.The main research methods and results of the paper are as follows:(1)The management mode of stockyard space resources is introduced,and the stockyard space scheduling problem under the dynamic open stacking mode is defined.The analysis of the space and time characteristics of the coal stockpile occupying the stockyard in current research is sorted out,and a mathematical model of the space scheduling problem of coal stockyard with special position constraint is established,which is based on the essential similarity between the coal stockyard space scheduling problem and the two-dimensional strip packing problem.(2)Two methods are designed to solve the space scheduling problem of coal stockyard: a constraint programming model based on interval variables is established for the space scheduling problem of coal stockyard,and the constraint programming method is used to solve the problem;A greedy random adaptive search procedure algorithm is designed,which uses the improved Bottom Left algorithm to determine the position of the rectangular coal stockpile,and the position of several rectangular coal stockpiles of the same vessel is improved to satisfy the position constraint between several rectangular coal stockpiles of the same vessel.(3)The test data is generated according to the demand of port ships,and through experimental research,the effects of the greedy function,greedy parameters,and neighborhood structure on the performance of the greedy random adaptive search procedure algorithm are analyzed and the optimal parameter values are determined;Further generate different size of data,and combined it with the real data from port;Experiments are carried out to compare the performance of the constrained programming and the greedy random adaptive search procedure algorithm on the solving of coal stockyard scheduling problem,and the conclusion that the greedy random adaptive search procedure algorithm performs better on real application scale data is obtained.