Study On The Models And Algorithms Of Integrated Loading And Unloading Operations Of Coal Port

As the important transportation hub and regional economic gateway,ports play an important role in promoting national economic development and industrial operation.With the continuous development of market and technology,the world’s leading container ports have greatly improved the production and operation efficiency of the ports by using computer decision analysis tools.In contrast,the bulk cargo ports,which are represented by coal,are still in the stage of relying on manual experience for port production scheduling due to its complex production process.The demand for smart port transformation,increasing customer demand and the conflict between efficient automation equipments and inefficient manual scheduling methods all urge the coal port to optimize the port production scheduling mode as soon as possible and further improve the port operation efficiency.The issue of integrated scheduling of loading and unloading operations in coal ports is the central link in the production and operation of coal ports.On the whole,this problem is a complex decision-making problem,involving a series of combinatorial optimization problems such as operation volume allocation,operation equipment selection and operation time scheduling.Due to the structural complexity and different background needs of such problems,most domestic scholars mainly conduct research on some aspects of their production processes.The research carried out by some foreign scholars around the integrated scheduling of coal production and transportation is also limited by the differences in production processes and management models,and it is difficult to directly apply to China’s coal ports.Based on the detailed introduction and analysis of the integrated scheduling problem of loading and unloading operations in China’s representative coal ports,this paper discusses the essence and solution complexity of the problem.On this basis,a step-by-step solution method is proposed,which first formulates the production plan with the maximum throughput as the goal,and then schedules the production tasks with the shortest operation completion time as the goal.The problem of each stage is clearly defined by network flow and constraint programming models.Aiming at the NP hard attribute of the scheduling problem,an improved constrained programming method and a hybrid algorithm based on constrained programming and variable neighborhood search are designed.Based on the production and operation scenarios of large domestic coal ports,this paper expounds,discusses and studies the integrated decision-making of coal port loading and unloading operations.The main research results of this paper are as follows:(1)The layout,production process and current management mode of coal ports are introduced in detail,and through the comparison with the integrated management mode,the shortcomings of the current management mode are explained,and the efficiency and necessity of the integrated management mode are clarified.(2)Through the comparison with flexible job shop scheduling problem,the problem structure and solution complexity of the integrated scheduling problem of loading and unloading operations in coal ports are analyzed.Based on the port management requirements and production processes,the problem is defined and mathematically described.Aiming at the requirements of the sequence of operation tasks,the proportion of operation tasks,the collision avoidance of operation equipments,and the inventory limit of operation stacking,a complete mathematical model of the problem is established by using network flow and constraint programming methods with efficient solution performance.(3)The simplified problem of integrated scheduling of coal port loading and unloading operations is introduced: the coal port equipment scheduling problem,and the structure of the problem and the demand for the solution algorithm are analyzed and summarized through multi-scale data experiments on the simplified problem.A multi-dimensional experiment was conducted on the two-step solution method based on network flow and constraint programming to determine the optimal parameter configuration of the algorithm,and the two-step solution method was improved by analyzing the problem structure.By analyzing the problem structure and algorithmic properties,an improved algorithm based on constraint planning and variable neighborhood search is designed.(4)Through comparison and analysis with the results of manual scheduling,the reliability and efficiency of the two-step solution method are proved.Based on the actual production data and coal port management requirements,45 sets of experimental examples of different scales were designed and generated.Aiming at the problem of coal port equipment scheduling and the problem of integrated scheduling of coal port loading and unloading operations,different solving algorithms are used to solve multiscale experimental examples,and the solution performances of different algorithms are compared and analyzed.