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Application Research Of Projection Pursuit Method In The Ecological System Evaluation

Posted on:2012-08-10Degree:MasterType:Thesis
Country:ChinaCandidate:W P ZhenFull Text:PDF
GTID:2131330335970556Subject:Applied Mathematics
Abstract/Summary:PDF Full Text Request
Projection pursuit model,a technology of dimensionality reduction,is a new statistical method to analyze and process nonlinearity and abnormal distribution multi-dimension data to get the rusult of research and analyze multi-dimension data through calculations. In the projection pursuit method, if it can construct to find the optimal projection direction, is the key to solve practical problems. While genetic algorithm is the effective algorithm to solve this problem.The method of projection pursuit, the basic theory of ecosystem health and the research progress of it was discussed by this thesis. The mathematical method of Lanzhou city ecosystem health assessment was determined. Projection pursuit principal component analysis was used to the ecological risk assessment of shule river basin, and calculated the real case. The following several main conclusions was getted.1. In this thesis, a health assessment of urban ecosystem was conducted in Lanzhou City by this model.17 indicators were selected to health assess. The Lanzhou health evaluation indicators system was established.2. It showed that healthy degree of Lanzhou city ecosystem rises continuously, but health level all in sub-health during 2004~2008. The development of Lanzhou urban economy is limited because it is a heavy industry city, and air pollution in the city is serious for its special landform. How to coordinate the relationship between environmental and economic development in the future, is the pinnacle of Lanzhou.3. Projection pursuit principal component analysis was used to the ecological risk assessment of shule river basin, three irrigation area of the water resources carrying capacity. The results are changma irrigation area water resources carrying capacity,followed by the shuangta irrigation area, the worst is the huahai irrigation area. This has inevitable relation with the water distribution of shule river basin, and the location of the three irrigation. River basin management departments should strengthen coordination efforts to irrigation water supply and demand to the economic benefit maximization with each irrigation area. The evaluation result of this method has higher resolution, and more traditional principal component analysis process simple, and the method has better operability.
Keywords/Search Tags:projection pursuit model, genetic algorithm, urban ecosystem health assessment, ecological risk assessment
PDF Full Text Request
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