Presentation on theme: "Smart Shopper A Consumer Decision Support System Using Type-2 Fuzzy Logic Systems Ling Gu 2003 Fall CSc8810."— Presentation transcript:
1Smart Shopper A Consumer Decision Support System Using Type-2 Fuzzy Logic Systems Ling Gu2003 FallCSc8810
2Outline Decision Support System Why Fuzzy Logic System Type-1 Fuzzy Logic Systems and membership functionType-2 Fuzzy Logic Systems and membership functionProposed ApproachImplementationDiscussion and ConclusionFuture Work
3Decision support systems The consumer decision support systems is to extract products that match users’ queries, and filter out unmatched products.The match is measured by a ranking function.The filtering function calculates the ranking of each product and filters out the lower ranked products.
4Why Fuzzy Logic SystemThe fuzziness nature of the e-commerce makes the ranking process much more difficult.User's queries are often complex and fuzzy.They are contradictory and need to be balancedThe general framework of fuzzy reasoning allows handling of this uncertainty.
5Type-1 Fuzzy Logic Systems Type-1 fuzzy sets represent uncertainty by numbers in the range [0, 1].FuzzifierInferenceRulesDefuzzifierInputProcessingOutputAnalyzer(a)Crisp
6Type-1 Membership Function Two-dimension in which each element of the type-1 fuzzy set has a membership grade that is a crisp number in [0, 1].1000P200010,0LowMediumHigh(a)
7Type-2 Fuzzy Logic Systems Type-2 fuzzy sets are an extension of type-1 fuzzy sets in which uncertainty is represented by an additional dimension.CrispInputFuzzifierInferenceRulesType-ReducerProcessingOutputAnalyzerDefuzzifier(b)TypeReducedSet
8Type-2 Membership Function Three dimensions in which each element of the type-2 fuzzy set has a membership grade that is a fuzzy set in [0, 1].5Q1010, 0LowMediumHigh(b)
9Advantages for Type 2 FLS This extra third dimension in type-2 fuzzy logic systems (FLS) gives more degrees of freedom for better representation of uncertainty compared to type-1 fuzzy sets.Type-2 fuzzy sets are useful in circumstances where it is difficult to determine the exact membership function for a fuzzy set.Using type-2 FLS provides the capability of handling a higher level of uncertainty and provides a number of missing components that have held back successful deployment of fuzzy systems in human decision making.
10Interval Type-2 Membership Function Special case: type-2 membership function is an interval set that the secondary membership function is either zero or one0.5x10, 0avg0.65x = 0.65(b)(a)HL
14ImplementationJava servlet is used to implement this type-2 FLS-based consumer decision support system.Two inputs: one (price) uses type-1, the other (quality) uses type-2.The result (rank) is a fuzzy set and ranges from the low limit to the high limit.
17DiscussionA better results might be obtained by defined the membership function of price also to be type-2.It is important to define reasonable membership functions.Using an interval input for the price, which provides more freedom for users.Provide a weight function.
18ConclusionAn up-low limit method has been proposed to handle the complex calculations of type-2 FLS.This approach reduces the complex calculations of type-2 to type-1.A fuzzy output of an interval type-2 FLS can be obtained using the up-low limit technique. This fuzzy output provides more reasonable conclusion for the users.
19Future Work Use the generation of membership functions. More type-2 variables.Weight function.Interval inputs to improve the system.
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