Study On Leakage Analysis And Evaluation Of Water Supply Network Based On Set Pair Principle

Currently, the shortage of fresh water resources is increasing, water pollution is more and more serious, and leakage of water supply network is also further causing a lot of water resources waste in China, which all are hindering the co nstruction of water-saving society and water ecological civilization, so the studie s on the leakage of water supply network have been imminent.There are a large number of uncertainties during the study of the leakage problem. The set pair principle is a new method to treat the problem of uncertainty, which is based on the collection. The key of the set pair principle is to build and calculate the connection degree between the two collections. This paper is based on the set pair principle to study the leakage of water supply network.Firstly, leakage analysis model of water supply network was constructed based on the set pair principle. “Pipe diameter, water pressure, thickness of covering soil, where the road grade” were selected as the main factors leading to pipeline leakage. The expression of ternary connection degree was set up between the dependent variables and independent variable, which revealed the connection of them from the identical,discrepancy and contrary aspects. The results show that from the same trend the bigger of “Pipe diameter, thickness of covering soil, where the road grade” there are, the more excellent the pipeline will be, and the smaller of the water pressure there is, the more excellent the pipeline will be.Secondly, health evaluation model of water supply network was constructed based on the set pair principle. “Pipe diameter, water pressure, thickness of covering soil, where the road grade, pipe age” these five factors were selected for health evaluation indexs, and the same time we determined the index weight using three scales of AHP. Considering the characteristics of fuzziness in the health grade assessment standards, the index weight could reduce this situation during the creating of the expression of ternary connection degree. Attribute recognition criterion was also cited to avoid a difference uncertainty coefficient i value. Finally we nailed down the health evaluation of the evaluated pipelines.Thirdly, leakage forecast model was constructed based on the set pair principle. The similarity between the leakage prediction samples and the historical samples was measured from three aspects of identical,discrepancy and contrary during the creating of the expression of ternary connection degree. Giving a difference uncertainty coefficient “i” value to calculate the connection degree, we could use the most similar number of historical samples to obtain predictions. Comparing with grey system model and BP neural network model, the higher forecast precision was obtained on the set pair principle.In all, the paper showed that the set pair principle was feasible to study on leakage analysis and evaluation of water supply network as a new method.