Research On Optimization Of Construction Schedule Plan Of The Interchange Nodes In Port Collecting And Distributing Network

With the port throughput and urban traffic volume increasing year by year,the port collection and distribution system has already become one of the main factors restricting port service level.The interchange nodes in port collecting and distributing network,which is influenced by port and urban transport coupling effect,are subject to external environmental impact,and are prone to accidents,vehicle congestion and other random events.And the throughput ability of interchange node in collecting and distributing network could be effectively improved by establishing three-dimensional port collecting and distributing network traditional nodes and constructing interchange nodes.However,due to the coupling relationship between port throughput and collecting and the traffic volume of distributing and collecting network nodes is ambiguous and the investment of interchange nodes construction is enormous,clarifying the relationship between the increasement of port throughput and the construction of collecting and distributing network interchange nodes,and studying the theory and methods to optimize the construction schedule plan of interchange nodes are necessary.In this paper,based on the operation characteristics of container ports,and the road traffic features of collecting and distributing network,two optimization methods of construction schedule plan of the interchange nodes in collecting and distributing network are proposed: The one is PTG method which is based on throughput growth timing and the other is PLCC method which is based on the total cost of collecting and distributing network during port life cycle.According to the yearly dynamic change of port throughput with time,the PTG method is used to build the simulation model of container port collecting and operating operation system which is based on throughput growth timing,and to reveal the intrinsic relationship between port throughput and traffic volume of each node in collecting and distributing network,then take vehicle delay time at nodes and other indicators into consideration evaluate the service level of each node,and finally determine the construction time of interchange node in network each node,the time of vehicle delay and so on,the service level of each node is evaluated,and the time of construction of network interchange node is determined.The PLCC method aims at the minimum cost(including the construction cost of interchange nodes,delay cost of vehicle caused by congestion and the energy consumption cost)of collecting and distributing network during total life cycle,and build the simulation model of construction schedule plan of the interchange nodes.Total cost of the total life cycle of the port based on the total cost of the distribution network(the cost of construction of the transit node,the vehicle delay cost and the energy consumption cost caused by the congestion)in the whole life cycle.Simulation Model of Node Construction Timing Simulation.The micro-traffic simulation model is used to measure the micro-traffic characteristics of the vehicle at the node,and the output of the simulation model is taken as the input parameter of the optimization model.Finally,the whole life cycle within the construction of the cross-node timing on the basis of this.The micro-traffic simulation model of collecting and distributing network nodes is embedded in the dynamic programming model of the construction schedule plan of interchange nodes,thus measuring vehicles' traffic features at nodes.As the input parameters of optimized model,the output result of simulation model will finally determine the construction schedule plan of each node during life cycle.Taking a container port in the north as an example,the optimization results of the two methods proposed in this study are compared and analyzed.The results of PTG method show that the construction of the 2 # interchange node can meet the requirements of the port development for collecting and distributing network;The PLCC method results show that if complete the construction of 3 # interchange node in 2016,and of 4 # interchange node in 2018,the least total cost of collecting and distributing network could be reached in the case of congestion alleviation.The two methods proposed in this study can both effectively alleviate the delay and congestion of the vehicle at the nodes in collecting and distributing network,and provide theoretical support for the scientific and rational planning of the port collecting and distributing network.