class06

class06 - WhatIsAssociationMining? q Association rule...

Info iconThis preview shows pages 1–7. Sign up to view the full content.

View Full Document Right Arrow Icon
What Is Association Mining? Association rule mining: Finding frequent patterns, associations, correlations, or causal structures among sets of items or objects in transaction databases, relational databases, and other information repositories. Frequent pattern : pattern (set of items, sequence, etc.) that occurs frequently in a database [AIS93] Motivation: finding regularities in data What products were often purchased together? — Beer and diapers?! What are the subsequent purchases after buying a PC? What kinds of DNA are sensitive to this new drug? Can we automatically classify web documents?
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Why Is Frequent Pattern or Association  Mining Important? Foundation for many essential data mining tasks Association, correlation, causality Sequential patterns, temporal or cyclic association, partial periodicity, spatial and multimedia association Associative classification, cluster analysis, iceberg cube, fascicles (semantic data compression) Broad applications Basket data analysis, cross-marketing, catalog design, sale campaign analysis Web log (click stream) analysis, DNA sequence analysis, etc.
Background image of page 2
Association Rule Mining Given a set of transactions, find rules that will predict the occurrence of an item based on the occurrences of other items in the transaction Market-Basket transactions TID Items 1 Bread, Milk 2 Bread, Diaper, Beer, Eggs 3 Milk, Diaper, Beer, Coke 4 Bread, Milk, Diaper, Beer 5 Bread, Milk, Diaper, Coke Example of Association Rules {Diaper} {Beer}, {Milk, Bread} {Eggs,Coke}, {Beer, Bread} {Milk}, Implication means co-occurrence, not causality!
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Definition: Frequent Itemset Itemset A collection of one or more items Example: {Milk, Bread, Diaper} k-itemset An itemset that contains k items Support count ( σ ) Frequency of occurrence of an itemset E.g. σ ({Milk, Bread,Diaper}) = 2 Support Fraction of transactions that contain an itemset E.g. s({Milk, Bread, Diaper}) = 2/5 Frequent Itemset An itemset whose support is greater than or equal to a minsup threshold TID Items 1 Bread, Milk 2 Bread, Diaper, Beer, Eggs 3 Milk, Diaper, Beer, Coke 4 Bread, Milk, Diaper, Beer 5 Bread, Milk, Diaper, Coke
Background image of page 4
Definition: Association Rule Example: Beer } Diaper , Milk { 4 . 0 5 2 | T | ) Beer Diaper, , Milk ( = = = σ s 67 . 0 3 2 ) Diaper , Milk ( ) Beer Diaper, Milk, ( = = = c Association Rule An implication expression of the form X Y, where X and Y are itemsets Example: {Milk, Diaper} {Beer} Rule Evaluation Metrics Support (s) Fraction of transactions that contain both X and Y Confidence (c) Measures how often items in Y appear in transactions that contain X TID Items 1 Bread, Milk 2 Bread, Diaper, Beer, Eggs 3 Milk, Diaper, Beer, Coke 4 Bread, Milk, Diaper, Beer 5 Bread, Milk, Diaper, Coke
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Basic Concepts: Frequent Patterns and  Association Rules Itemset X={x 1 , …, x k } Find all the rules X Y with min confidence and support support , s , probability that a transaction contains X Y confidence , c, conditional probability
Background image of page 6
Image of page 7
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 08/29/2011 for the course CAP 4770 taught by Professor Staff during the Fall '08 term at FIU.

Page1 / 98

class06 - WhatIsAssociationMining? q Association rule...

This preview shows document pages 1 - 7. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online