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Mining Negative Association Rules. Xiaohui Yuan, Bill P. Buckles Zhaoshan Yuan Jian Zhang ISCC 2002. Outline. Motivation Problem define Algorithm Conclusion & Thought. Motivation. conf (age < 30 →coupe ) = 0.3/0.4 =75% conf (age > 30 → not buy coupe) = 0.5/0.6 = 83.3%. Problem.
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Mining Negative Association Rules Xiaohui Yuan, Bill P. Buckles Zhaoshan Yuan Jian Zhang ISCC 2002
Outline • Motivation • Problem define • Algorithm • Conclusion & Thought
Motivation • conf(age < 30 →coupe ) = 0.3/0.4 =75% • conf(age > 30 →not buy coupe) = 0.5/0.6 = 83.3%
Problem • The difficulty for mining negative rules • Can’t simply pick threshold values for support and confidence. • Thousands of items are included in the transaction records.
Sibling relationships • Called LOS and denote as[i1,i2…..,im] • [IBM Aptiva , Compaq] • Extend [IBM Aptiva , Compaq, Notebook]
LOS • Locality of Similarity (LOS) • Similarity assumption • Sibling rule • If the item set X’ = {i1, i2,….ik,…,im} is the same as X except item ik is substituted for ih. • Rule r :X→Y and Rule r’:X’→Y
Discover Negitive Rule • If rule r’:X’→Y is not support ,it may exist negative rule. • Salience measure (distance betewwn conf level) • E():estimated conf
Condictions • for qualify a negative rule • there must exist a large deviation between the estimated and actual confidence. • the support and confidence are greater than the minima required.
Pruning • Equivalent or similar pair • Exam: • Negative rule and positive rule are couple • Exam:”female →BuyHat “ and “﹁male→BuyHat”
Conclusion • It’s not depend on numbers of transactions • Complexity O(P x L) • P :number of positive rule • L :average size of LOS
Thought • Estimate from postive to find negative cost , how ?