International Business Machines Corporation

V V V Prasad

Charu Chandra Aggarwal

Ramesh Chandra Agarwal

A system and method for generating itemset associations in a memory storage system comprising many transactions, with each transaction including one or more items capable of forming the itemset associations. The method involves generating a lexicographic tree structure having nodes representing itemset associations meeting a minimum support criteria. In a recursive manner, for each lexicographic least itemset (node) P of the lexicographic tree structure, candidate extensions of the node P are first determined. Then, the support of each of the candidate extensions is counted to determine frequent extension itemsets of that node P, while those itemsets not meeting a predetermined support criteria are eliminated. Child nodes corresponding to the frequent extensions and meeting the predetermined support criteria are created. For each frequent child of node P, all itemset associations for all descendants of node P are generated first. Thus, the lexicographic tree structure is generated in a depth first manner. By projecting transactions upon the lexicographic tree structure in a depth-first manner, the CPU time for counting large itemsets is substantially reduced.

Depth first method for generating itemsets

A method for automatically generating associations of items included in a database. A user first specifies a support criteria indicating a strength of desired associations of items contained in the said database. Then, a recursive program is executed for generating a hierarchical tree structure comprising one or more levels of database itemsets, with each itemset representing item associations determined to have satisfied the specified support criteria. The recursive program includes steps of: characterizing nodes of the tree structure as being either active and enabling generation of new nodes at a new level of the tree, or inactive, at any given time; enabling traversal of the tree structure in a predetermined manner and projecting each of the transactions included in the database onto currently active nodes of the tree structure to generate projected transaction results; and, counting the projected transaction results of the projected transactions at the active nodes to determine whether the further itemsets satisfy the specified support criteria. All itemsets meeting the specified support criteria are added to the tree structure at a new level.

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Hyderabad Telangana, India

V V V Prasad