Study On The Method Of Dam Health Diagnosis Based On Rough Set And Evidence Theory

With the continuous development of our national dam construction and construction of high dams in the southeastern regions,dam health diagnosis has drawn more and more attention.However,the existing methods of dam health diagnosis are dealing with huge information with redundant and useless information,have strong subjectivity in diagnosis and are not applicable with index system in dam health diagnosis when dealing with uncertainty problems of monitoring information.So based on previous research results,the dissertation combines rough set and evidence theory,applies it into dam health diagnosis and establishes an dam health diagnosis model based on rough set and evidence theory,which provides a new approach for dam health diagnosis.The main research results of the dissertation are as follows:(1)Through analysis of the limitations of the research on uncertainties of dam health diagnosis,the dissertation researches advantages of the combination of rough set and evidence theory,explains the feasibility and rationality of the application of the method in dam health diagnosis.(2)Trough applying concepts of rough set theory and evidence theory into dam health diagnosis,aiming at characteristics of dam health diagnosis,the dissertation improves attribute reduction method and evidence fusion method,proposes subjective and objective fusion weights.The key parameters,such as attribute importance,membership degree,basic probability and so on,are estimated and calculated in the dissertation.It lays the foundation for the application of rough set and evidence theory in dam health diagnosis.(3)The dissertation researches the dam health diagnosis method based on rough set and evidence theory.With a start from establishing the dam health diagnosis index,decision tables can be obtained by quantitative evaluation of attribute indexes and and discrete valuation.After attribute reduction,evidential probability assignment is conducted based on decision tables.Applying weights and evidence fusion method,evaluation results can be obtained and dam health can be diagnosed comprehensively.Combined with engineering project case,the method proposed in the dissertation is proved to be reliable and reasonable.This dissertation has several new ideas in the following aspects:Firstly,attribute reduction method is improved to adapt the requirements of dam health diagnosis;Secondly,calculation method of subjective and objective fusion weights is improved and weights of dam health diagnosis are measured properly;Thirdly,evidence fusion method is improved which makes full consideration on evidence conflict existed in the process of evaluation.Owing to the complexity of dam health diagnosis and the limitation of some objective factors,the research is preliminary,further study should be made on the application of rough set and evidence theory in the dam health diagnosis.