| The development of social and economy has put forward higher request for transportation, and the construction of transport infrastructure has entered into a rapid development stage in our country. The various modes of transport not only need to expand the scale of network and enhance network level, the more important is to accelerate the perfect network structure and eventually realize the development goal of setting up a sound, smooth, safe, convenient and intelligent modern comprehensive transportation system. Comprehensive transport network is the basic hardware facilities of the comprehensive transportation system, whose layout quality affects the operation of all kinds of transportation. Reasonable network structure and integration of connection is beneficial to give full play to comparative advantage and comprehensive benefits of all transportation modes. This dissertation studied the regional comprehensive transport network layout planning method, layout optimization model and the decision-making method.Firstly, the network structure of comprehensive transportation system, the characteristics of each transport mode, the division of space level of comprehensive transport network planning, the distinction of regional and urban comprehensive transport planning and the selection of regional transport network layout modes were analyzed, and further the content and principles of regional comprehensive transport network layout planning were made clear. In the comprehensive transport network planning, the precondition of network layout optimization is the analysis of the transportation distribution nodes in this region. The selection principle of control nodes and the calculation of nodes importance degree were analyzed, then the ant colony clustering method was applied to nodes classification as the basis of transport network layout.Secondly, on the basis of analysis on the influence factors of the regional comprehensive transport network layout and network evolution, the network layout method and process were studied. The layout of the comprehensive transport network is under the condition of obtaining traffic demand to construct the transport network. Different network layout should feedback the change of demand and the mode selection, so the network layout is a process of constantly and repeatedly adjusting and improving. Considering regional transportation mainly meeting the middle and long distance travel and transport demand, a bi-level programming model was built taking the minimum time turnover of middle and long distance transportation of all modes as the objective function, in addition, the objective function considering the accessibility requirements to stations, ports and hubs. To generate transport network, taking connection importance degree between nodes as initial heuristic condition, a transport network layout algorithm was designed and implemented based on ant colony search. In searching, the probability of selecting next node was not only determined by the pheromone and the time distance to neighboring nodes, but also the guidance of terminal node. The application of the method was illustrated by an example.On the basis of the existing calculation method of network connectivity, put forward to consider the connection importance between pairs of nodes as influencing factor of connection reliability so to optimize the network layout. With the weighted connectivity of network as one of the objectives, at the same time combined with the connection efficiency and cost, a multiple objectives programming model was constructed. Determine the optimum scheme by comparing the objective function values of random generating layout schemes conforming to connection demand so as to distinguish the different requirements of nodes for reliable network connection, which can form more rational network topological structure. Furthermore, in order to judge the connectivity of network, for the topological structure being composed of different modes of transport lines with the characteristics of complex graph, the theory of spanning tree was applied to analyze the network connection quality. A computation model of edge influence degree was proposed to evaluate the influence to the network connectivity, in terms of the changes in the counting of spanning trees after removing one of edge as well as considering the traffic capacity, actual traffic load, function and administrative status of links.Then based on the construction of technology evaluation index system of comprehensive transport network layout, in view of the index weight and attribute values have the characteristics of subjectivity and randomness, a group stochastic decision method was proposed to sort and select layout planning schemes with applying Monte Carlo simulation. Aggregating the sort preference for indexes importance of experts to simulate the index weight subjected to the statistical distribution, while considering the uncertainty factors influencing the index value, and combined with the objective entropy weight, the comprehensive evaluation value can be calculated. Determine the ranking and difference of schemes according to the dominance degree of sorting position, which can reflect the influence of uncertainty factors on the sorting result. Through a numerical example shows the effectiveness of the method. The evaluation considering the subjective and objective factors and stochastic characteristics can provide scientific decision references for network layout.On the analysis of the comprehensive transport network layout planning process and characteristics, the construction of regional comprehensive transport network planning intelligent group decision support system (IGDSS) was put forward. According to the system function and design requirement, the overall system structure and composition were presented, and the composition of database, model base, method base and knowledge base and each subsystem module design were analyzed.Finally, taking Nanchong city as an example, the nodes selection and the regional comprehensive transport network layout were analyzed.The layout method and models researched in this dissertation, as well as the evaluation and decision method of layout schemes, can provide regional comprehensive transport network layout with theoretical support and scientific decision basis, at the same time can also provide the basic models and methods for the construction and implementation of the IGDSS. |
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