Fuzzy operator trees for modeling utility functions [Elektronische Ressource] / vorgelegt von Yu Yi

Fuzzy Operator Trees for Modeling UtilityFunctionsDissertationzurErlangung des Doktorgradesder Naturwissenschaften(Dr. rer. nat.)demFachbereichMathematikundInformatikderPhilipps UniversitätMarburgvorgelegtvonYuYiausChangsha,ChinaMarburg/Lahn2008VomFachbereichMathematikundInformatikderPhilipps UniversitätMarburgalsDissertationam08.12.2008angenommen.Erstgutachter: Prof. Dr. EykeHüllermeierZweitgutachter: Prof. Dr. BerndFreislebenTagdermündlichenPrüfungam12.12.2008AbstractIn this thesis, we propose a method for modeling utility (rating) functions based ona novel concept called Fuzzy Operator Tree (FOT for short). As the notion sug gests, this method makes use of techniques from fuzzy set theory and implements afuzzy rating function, that is, a utility function that maps to the unit interval, where0 corresponds to the lowest and 1 to the highest evaluation. Even though the origi nal motivation comes from quality control, FOTs are completely general and widelyapplicable.Our approach allows a human expert to specify a model in the form of an FOT ina quite convenient and intuitive way. To this end, he simply has to split evaluationcriteria into sub criteria in a recursive manner, and to determine in which way thesesub criteria ought to be combined: conjunctively, disjunctively, or by means of anaveragingoperator. Theresultofthisprocessisthequalitativestructureofthemodel.A second step, then, it is to parameterize the model.