Research On Regional Water Security Assessment Model And Its Application

Water security assessment is the premise and basis of establishing security system and decision of water security. The status of regional water security can be judged by quantitative research of water security. So the related decision scheme of water security can be adopted in ordor to ensure sustainable development of water security, avoiding the blindness of decision and reduce unnecessary waste of personnel and water resources. According to the defect that most of water security assessment is qualitative research, this paper established the standard and the water security synthesis assessment model based on vague set after analyzing the results of related research. It analyzed the water security status of central shaanxi area through the combination of qualitative and quantitative analysis, and also established an early warning model of water security based on support vector machines, using the model of early warning, forewarned the water security status of 2015 year and 2020 year on the base year of 2009, in order to provide scientific basis for establishing security system and decision of water security in central Shaanxi.The principal results of this paper are as following:(1)Defined the water security, and analyzed the connotation and extensionality of water security.Based on the theory of sustainable development and resources and environment carrying capability, and the conception of complex ecosystem of society-economic-nature, this paper defined the water security as: under the certain society economic condition, the water quality should be satisfied with the standard of living and production and ecology, and the water quantity should be meet not only the living and production but also the sustainable development of ecological environment and society economic and the health running water cycle system and carry out the sustainable development and utilization of water resources. After analyzing the connotation and extension of water security, this paper summed the extensionality of water security as health security , grain security, ecological environment security, economic security, social security and national security etc.(2)Established index system of water security assessment and its evaluation standard.This paper established index system of regional water security assessment by using sustainable development index system for reference firstly. The index system includes total target layer, the criterion layer and index layer. The total target layer is the degree of water security. The criterion layer includes six factors, composed of the degree of water resources security, society economic security, drinking water security, grain security, entironment and management security etc. The index layer includes 23 indexes in the criterion layer. Secondly, this paper established the Classification standards of each index on the basis of referring domestic and foreign related standards and research achievement, combining the water resources condition and economic development status of research region. Accordingly, each index could be classified as five levels, including extreme safety, safety, basic safety, unsafety and danger etc.(3)Established water safety system assessment model based on vague set.According to the complex, multilayer and fuzziness of water security system, and vague set can co-express supporting information, opposing and waiver information of decision makers. Comparing with the fuzzy, which extends the expressive power in handling unconsidering neutral information. So this paper established water security assessment model based on vague set. The weight values of each index was given by analytic hierarchy process firstly. Secondly, retained 15 experienced experts to give the low bound of each index satisfaction degree and the upper bound of each index dissatisfaction degree according relative membership degree of each index. Thirdly, determined the vague value of evaluation objects after comparing index weight value with relative low bound of satisfaction degree and the upper bound of dissatisfaction degree. Finally, calculated the value of score function based on the vague value of evaluation objects. In order to carry out the qualitative assessment of the water security, this paper chose the threshold value of the same classification of each index as four assessment objects. The related Vague value and grade value was computed by the water security assessment model based on vague set. The grade value is the standard of water security status.(4)Established a regional water security early warning model based on Support Vector Machines(Abbr. SVM).SVM is new pattern recognition method based on the statistics theory recent years. SVM used the minimum structure risk instead of the traditional experience risk. So it can get the global optimal point after sloving a quadratic optimal function, it can solve the problem of partial extreme when it is inevitable using the nerve net method. SVM topology structure is decided by support vector and avoid the problem of test of experience of topology structure by traditional nerves net system. SVM has advantages in solving the small sample, nonlinear and high dimension patterns recognition. This paper established a water security early warning model based on SVM for the small measured sample of water security early warning. Chosing radial basis function as the kernel function of model, and solving the model by using the software of LS-SVMlab1.7.(5)The application and analysis of water security assessment and early warning model.According the evaluation standard of regional water security assessment, using the model of water security assessment in basis on vague set, assessed the water security status of central Shaanxi in 2004～2009. The result shows that the water security status is basic safety all city, but the general trend of water security status is closing to the safety gradually. It fit well with the actual situation of central Shaanxi. It also proved the model is practical and scientific in regional water security assessment. This paper also forewarned the water security status of 2015 year and 2020 year on the base year of 2009. The result shows that the water security status is basic safety all city, it was consistent with the result of water security assessment. It also shows that the water security status are still basic safety, but the status are Upturn year by year. It fit well with the actual situation of central Shaanxi. And also proved the early warning model is practical and scientific, the result of forewarning is visual and credible.The innovation of this paper includes:(1)Established the standard of water security assessment.(2)Established the synthesis assessment model based on vague set of water security. and combining the standard of water security assessment, accomplished the water security assessment through the combination of qualitative and quantitative analysis.(3)Applying with the classification algorithm theory of support vector machines, established a model of regional early water security warning.