Sewer rehabilitation criteria evaluated byfusion of fuzzy indicators

摘要

This paper deals with definition and assessment of decision criteria for sewer assetrnmanagement. The work was prepared within a doctoral thesis (Ibrahim, 2008) and is part of a researchrnprogram (INDIGAU, 2007-2010, www.indigau.fr) supported by the French National Research Agencyrn(ANR). Three main ideas are exposed and illustrated in this paper. 1) Each rehabilitation criterion may bernseen as the result of successive aggregations of complementary indicators provided by various methods orrnsources (visual inspection, O&M data, investigation techniques, etc.) at several spatial scales (sewerrnsegment, catchment). 2) Combining indicators may be computed by means of a limited number of “if ...rnthen ...” rules. The French RERAU method provides 4x4 tables defining how to combine couples ofrnindicators, each one being evaluated on a four-grade ordinal scale (G4 being the highest gravity). 3) Thernaggregation tables can be converted into fuzzy aggregation rules associated to the use of fuzzy indicators.rnCompared to crisp data and rules, the use of fuzzy indicators and fuzzy rules provides finer results andrnimproves the robustness of the fusion process.