Research On The Brittleness Theory Of External Collecting And Distributing Network Of Urban Railway Passenger Depot

ABSTRACT:Traffic congestion has become the common problem in the great cities. It is one of the important reasons that the uncertainty and the volatility of traffic interference factors in addition to the contradiction between traffic capacity supply and demand. How to analyse traffic network characteristics and dynamic evolution mechanism for the uncertainty of interference and proposes the solution congestion scientific measures and countermeasures, which is a major issue of the urban transportation research meeting with. The railway passenger depot is an important source of the disturbance producing urban traffic congestion. With the acceleration of urbanization and the rapid development of high speed railway, the scale is enlarged and the function is strengthened unceasingl, the influence on the traffic congestion is more and more enormous. How to improve the urban transportation system standing in the height of the overall capacity, and aim at the large railway passenger in the urban traffic network interference effect and analyse dynamic evolution mechanism characteristics, theoretical model and the methods of the large railway passenger depot collecting and distributing network. So as to provide scientific basis for solving the problem of traffic congestion, optimizing the operation organization and emergency management decision, which is facing an important research problem currently.Large railway passenger depot is the integration of urban traffic hub seting several transport modes, so it is a complex system. At present, the complex system brittleness theory research is still the forefront topic of theoretic research; the action of dynamic evolution mechanism of the railway passenger depot collecting and distributing network under the uncertain interference is still lack of systematic research. The dissertation researches brittleness theory of the large railway passenger depot external distribution network.Based on the complex system brittleness theory, the dissertation mainly research on the collapse path model and the brittleness produce mechanism and evolution laws of the external collecting and distributing network of urban railway passenger depot. The main contents of the dissertation summarized as follows:(1) According to the actual operation organization management mode of urban railway passenger depot, the dissertation defines the boundary of collecting and distributing network and introduces the complex adaptive brittleness theory to research on the external collecting and distributing network of urban railway passenger depot and defines the collapse of collecting and distributing network. Finaly, it analyses the internal and external factores leading to the network excitation that laid a foundation for the subsequent brittleness research.(2) Based on the complex adaptive system theory, the dissertation builds an adaptive Agent topology of the external collecting and distributing network of urban railway passenger depot, and then it defines the collapse path and sets up the maximum/minimum collapse path model. According to the particularity of the model, it converts themodel into the shortest path problem and uses Lagrangian relaxation (Lagrangian Relaxation) algorithm to solve it. Finally, it takes the collecting and distributing network of Beijing south station for an example to verify the practicability and effectiveness.(3) Based on the complex adaptive theory, the dissertation builds the adaptability Agent topology structure model with each intersection and railway passenger depot as nodes of the collecting and distributing network and analyzes the IF/THEN evolution rules of each node. It takes the collecting and distributing network of Beijing south station for an example to get the state change of passenger node and the change of entropy of the whole collecting and distributing network under different IF/THEN evolution rules. It sums up four brittleness behaviors of the external collecting and distributing network of urban railway passenger depot. According to the time distribution regularity of the non-holidays and the holiday passenger flow, it gets the brittleness time distribution characteristics. According to the relative relations of spatial distribution between the railway passenger depots and urban, the railway passenger depots are divided into type of urban center, type of urban marginal and type of airport. It simulates the characteristics of brittleness of each type of the external collecting and distributing network of urban railway passenger depot. it concludes the brittleness time distribution rule and the rule in different type of urban railway passenger depot.(5) Based on the self-organized criticality theory, the dissertation researches on the brittleness power law characteristics and the fractal dimension characteristic of the collecting and distributing network. It expounds the self-organized criticality theory and the relationship between the brittleness and self-organized criticality. Based on improved cell transmission model and the sand heap, it takes Beijing south station for an example to research the brittleness collapse scale and power law characteristics and fractal dimension characteristic of brittleness collapse frequency.(6) The dissertation establishes the brittleness evaluation index system of a railway passenger depot and uses the improved catastrophe progression evaluation method to evaluate the state of the railway passenger station, and it concludes the brittleness identity, the brittleness opposition and the brittleness volatility of the evaluation value. According to the set pair theory, it gets the potential value tend to collapse and judges the brittleness level of each schemes. It takes Beijing south station for an example to discriminates the levels of brittleness of four different schemes including the present situation and the low, medium and high schemes of Beijing south station in2020.