closedversusmaximal

closedversusmaximal - © Tan,Steinbach, Kumar Infrequent...

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Unformatted text preview: © Tan,Steinbach, Kumar Infrequent Itemsets Maximal Itemsets Introduction to Data Mining 4/18/2004 Border 18 An itemset is maximal frequent if none of its immediate supersets is frequent Maximal Frequent Itemset TID 1 2 3 4 5 Items {A,B} {B,C,D} {A,B,C,D} {A,B,D} {A,B,C,D} Introduction to Data Mining Itemset {A} {B} {C} {D} {A,B} {A,C} {A,D} {B,C} {B,D} {C,D} Support 4 5 3 4 4 2 3 3 4 3 4/18/2004 19 Itemset Support {A,B,C} 2 {A,B,D} 3 {A,C,D} 2 {B,C,D} 3 {A,B,C,D} 2 An itemset is closed if none of its immediate supersets has the same support as the itemset © Tan,Steinbach, Kumar z Closed Itemset ABC ABCD BCE ACDE DE 1 2 3 4 5 ABC 12 AB 12 2 © Tan,Steinbach, Kumar 2 ABCD ABE AD 24 A 124 24 4 ABCE ACD AE B 123 4 BC BD ADE ABCDE ABDE 4 2 C 1234 ACE 123 Introduction to Data Mining ABD AC 124 Not supported by any transactions Items TID null 4 BCD BE D ACDE 2 3 245 Maximal vs Closed Itemsets BCDE BCE CD 4/18/2004 3 24 E 34 345 BDE CE 20 4 45 Transaction Ids CDE DE 2 ABD AC 124 2 ABCD ABE AD 24 © Tan,Steinbach, Kumar ABC 12 AB 12 A 124 Minimum support = 2 24 4 ABCE ACD AE B 123 4 2 BD ADE ABCDE ABDE ACE BC 4 BCD BE D ACDE 2 3 245 Introduction to Data Mining 4 123 C 1234 null 3 24 BCDE BCE CD E 34 345 BDE CE Closed but not maximal 4 45 4/18/2004 # Maximal = 4 # Closed = 9 CDE DE 21 Closed and maximal Maximal vs Closed Frequent Itemsets © Tan,Steinbach, Kumar Introduction to Data Mining Maximal vs Closed Itemsets 4/18/2004 22 ...
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This note was uploaded on 11/13/2011 for the course CIS 4930 taught by Professor Staff during the Spring '08 term at University of Florida.

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closedversusmaximal - © Tan,Steinbach, Kumar Infrequent...

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