Research And Application On Fuzzy Set And Risk Analysis For City Flood Control And Water Supply

During the expanding of China urban Proceeding, the city flood control and water supply would become the emphases of water resource stratagem regulating in china in 21 century. First, this paper presents the actuality of research field in global city flood control and that of China, and analyses the questions of research field in china city flood control. However, due to the wide-range and complex of its research contents, this paper will mainly deal with the risk and fuzziness of city flood control system. The major contents and research results are as follows:(1) With the problem of the multi-index decision-making, the rationality of evaluating result is decided by the rationality of index weight. Based on fuzzy decision-making analysis theory of professor Chen Shou-yu, the problem of the Index weight relativity-analysis is resolved by confirming the matrix of Index weight relativity-coefficient. Based on this, fuzzy decision-making analysis theory based on index weight relativity-analysis is developed and the means of computing the matrix of Index weight relativity-coefficient is provided.(2) The programming, design, construction and runnable management of city flood control according as the standard of city flood control, so, we can points out that the reasonable standard of city flood control is provided with important realistic signification. Through the analysis of the instance and compare with layer analysis method, we can points out that fuzzy decision-making analysis theory is provided with important application value and realistic signification in making standard of city flood control.(3) An urban storm water model has been established after analysis of the change of hydrological characteristics in urban areas and the deficiencies of traditional methods for hydrological calculation. Based on man-ning formula and equation of water volume balance the model can be used for hydrological and hydraulic analysis and calculation for urbanized areas. Based on GIS, urban storm water model parameter is calculated. The model has been used for an experimental area and satisfactory results have been obtained.(4) Considering the importance and complexity of prediction of hydraulic elements in the field of city water supply, this article applies the neural network with fuzzy pattern recognition model for prediction by combining fuzzy mathematics with neural network, and presents a new methods based on genetic algorithms and BP. With the case study of the examples, the new methods are reasonable, to some extent, this method solves the problem of so called local minimum of neural network model-learning.(5) Through the development of community, economy and population, the contradiction between supply and requirement of water resource is increased. So, the reasonable making level of risk in dynamic-control process of water level of flooding-period is provided with important realistic signification. Through the analysis of Bi Liu-He Teservoir, we can points out that fuzzy risk decision-making analysis theory is provided with important application value and realistic signification in making water line of flooding-period.Finally, a summary is given and some problems to be further studied are discussed.