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Fuzzy Measures and Integrals 1. Fuzzy Measure 2. Belief and Plausibility Measure 3. Possibility and Necessity Measure 4. Sugeno Measure 5. Fuzzy Integrals
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Fuzzy Measures Fuzzy Set versus Fuzzy Measure Fuzzy SetFuzzy Measure Underlying Set Vague boundaryCrisp boundary Vague boundary: Probability of fuzzy set RepresentationMembership value of an element in A Degree of evidence or belief of an element that belongs to A in X ExampleSet of large numberDegree of Evidence or Belief of an object that is tree
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Uncertainty vagueness: fuzzy sets ambiguity: fuzzy measures Vagueness: associated with the difficulty of making sharp or precise distinctions in the world. Ambiguity: associated with one-to-many relations, i.e. difficult to make a choice between two or more alternatives. Types of Uncertainty
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Fuzzy Measure vs. Fuzzy Set Ex) Criminal trial: The jury members are uncertain about the guilt or innocence of the defendant. –Two crisp set: 1) the set of people who are guilty of the crime 2) the set of innocent people –The concern: - Not with the degree to which the defendant is guilty. - The degree to which the evidence proves his/her membership in either he crisp set of guilty people or in the crisp set of innocent people. - Our evidence is rarely, if ever, perfect, and some uncertainty usually prevails. –Fuzzy measure: to represent this type of uncertainty - Assign a value to each possible crisp set to which the element in question might belong, signifying the degree of evidence or belief that a particular element belongs in the set. - The degree of evidence, or certainty of the element’s membership in the set
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Fuzzy Measure Axiomatic Definition of Fuzzy Measure Note:
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Note that where P(X) is a power set of X.
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Belief and Plausibility Measure Belief Measure Note: Interpretation : Degree of evidence or certainty factor of an element in X that belongs to the crisp set A, a particular question. Some of answers are correct, but we don’t know because of the lack of evidence.
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Belief and Plausibility Measure Properties of Belief Measure Vacuous Belief: (Total Ignorance, No Evidence)
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Belief and Plausibility Measure Plausibility Measure Other Definition Properties of Plausibility Measure
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How to calculate Belief Basic Probability Assignment (BPA) Note
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How to calculate Belief Calculation of Bel and Pl Simple Support Function is a BPA such that Bel from such Simple Support Function
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How to calculate Belief Bel from total ignorance Body of Evidence
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Ex) Let the universal set X denote the set of all possible diseases P: pneumonia, B: bronchitis, E: emphysema 기관지염 기종 mBel P0.05 B00 E P U B0.150.2 P U E0.10.2 B U E0.050.1 P U B U E0.61 where B: all the possible subset of A
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Robot Intelligence Technology Lab.
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Given Bel(·), find m(·) where |A-B| is the size of (A-B), size: cardinality of crisp set (A-B) Ex)
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How to calculate Belief Dempster’s rule to combine two bodies of evidence Example: Homogeneous Evidence AX A X
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How to calculate Belief Example: Heterogeneous Evidence AX B X
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How to calculate Belief Example: Heterogeneous Evidence
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Joint and Marginal BoE Marginal BPA Example 7.2
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Possibility and Necessity Measure Consonant Bel and Pl Measure
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Possibility and Necessity Measure Necessity and Possibility Measure –Consonant Body of Evidence Belief Measure -> Necessity Measure Plausibility Measure -> Possibility Measure –Extreme case of fuzzy measure –Note:
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Possibility and Necessity Measure Possibility Distribution
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Possibility and Necessity Measure Basic Distribution and Possibility Distribution Ex.
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Fuzzy Set and Possibility Interpretation –Degree of Compatibility of v with the concept F –Degree of Possibility when V=v of the proposition p: V is F Possibility Measure Example
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Summary Fuzzy Measure Plausibility Measure Belief Measure Probability Measure Possibility Measure Necessity Measure
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Sugeno Fuzzy Measure Sugeno’s g-lamda measure Note:
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Sugeno Fuzzy Measure Fuzzy Density Function
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Sugeno Fuzzy Measure How to construct Sugeno measure from fuzzy density
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Fuzzy Integral Sugeno Integral
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Fuzzy Integral Algorithm of Sugeno Integral
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Fuzzy Integral Choquet Integral Interpretation of Fuzzy Integrals in Multi-criteria Decision Making
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: evaluation value of attribute of the jth house, where Then, let the fuzzy measure: where g: degree of consideration (importance) of attributes in the evaluation process. Ex) Evaluation of the desirability of houses Let, where = price, = size, = facilities, =location and = living environment, and evaluation function: where m: # of houses, and
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The desirability of the jth houses: General linear evaluation model: - Performs well only when the attributes of evaluation are independent and the measures of evaluation are independent.
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- Practically, price ( ) and size ( ) are not independent. - Even if and are independent, the degree of consideration might not be independent, i.e., Additivity might not be true for measures. - F.I. Models are more general than the linear models. - Problem about Fuzzy Integral Evaluation Model ① How to find out the necessary attributes for evaluation. ② How to identify the fuzzy measure.
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