dm4part1 - University of Florida CISE department...

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University of Florida CISE department Gator Engineering Association Analysis Part 1 Dr. Sanjay Ranka Professor Computer and Information Science and Engineering University of Florida
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University of Florida CISE department Gator Engineering Data Mining Sanjay Ranka Spring 2011 Mining Associations • Given a set of records, find rules that will predict the occurrence of an item based on the occurrences of other items in the record Market-Basket transactions Example:
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University of Florida CISE department Gator Engineering Data Mining Sanjay Ranka Spring 2011 Definition of Association Rule Association Rule: Support: Confidence: Example: Goal: Discover all rules having support minsup and confidence minconf thresholds.
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University of Florida CISE department Gator Engineering Data Mining Sanjay Ranka Spring 2011 How to Mine Association Rules? Example of Rules: {Milk,Diaper} {Beer} (s=0.4, c=0.67) {Milk,Beer} {Diaper} (s=0.4, c=1.0) {Diaper,Beer} {Milk} (s=0.4, c=0.67) {Beer} {Milk,Diaper} (s=0.4, c=0.67) {Diaper} {Milk,Beer} (s=0.4, c=0.5) {Milk} {Diaper,Beer} (s=0.4, c=0.5) Observations: • All the rules above correspond to the same itemset: {Milk, Diaper, Beer} • Rules obtained from the same itemset have identical support but can have different confidence
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University of Florida CISE department Gator Engineering Data Mining Sanjay Ranka Spring 2011 How to Mine Association Rules? Two step approach: 1. Generate all frequent itemsets (sets of items whose support > minsup ) 2. Generate high confidence association rules from each frequent itemset Each rule is a binary partition of a frequent itemset Frequent itemset generation is more expensive operation
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University of Florida CISE department Gator Engineering Data Mining Sanjay Ranka Spring 2011 Itemset Lattice There are 2 d possible itemsets
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CISE department Gator Engineering Data Mining Sanjay Ranka Spring 2011 Generating Frequent Itemsets • Naive approach: – Each itemset in the lattice is a candidate frequent
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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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dm4part1 - University of Florida CISE department...

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