دانلود رایگان مقاله به روز رسانی کارآمد کشف مجموعه اقلام با سود بالا

Abstract

Most algorithms related to association rule mining are designed to discover frequent itemsets from a binary database. Other factors such as profit, cost, or quantity are not concerned in binary databases. Utility mining was thus proposed to measure the utility values of purchased items for finding high-utility itemsets from a static database. In real-world applications, transactions are changed whether insertion or deletion in a dynamic database. An existing maintenance approach for handling high-utility itemsets in dynamic databases with transaction deletion must rescan the database when necessary. In this paper, an efficient algorithm, called PRE-HUI-DEL, for updating high-utility itemsets based on the pre-large concept for transaction deletion is proposed. The pre-large concept is used to partition transaction-weighted utilization itemsets into three sets with nine cases according to whether they have large (high), pre-large, or small transaction-weighted utilization in the original database and in the deleted transactions. Specific procedures are then applied to each case for maintaining and updating the discovered high-utility itemsets. Experimental results show that the proposed PRE-HUI-DEL algorithm outperforms a batch two-phase algorithm and a FUP2-based algorithm in maintaining high-utility itemsets.

6. Conclusion and future work

This paper proposed a high utility mining algorithm based on pre-large concepts for transaction deletion (PRE-HUI-DEL) for effi- ciently maintaining and updating discovered high-transactionweighted utilization itemsets to derive high-utility itemsets. When transactions are removed from the original database, the proposed PRE-HUI-DEL algorithm partitions the itemsets in the deleted transactions into three sets with nine cases according to whether they have large (high), pre-large, or small transaction-weighted utilization in the original database and in the deleted transactions. Each set is then processed separately to maintain the discovered high-utility itemsets. When the total utility value of the inserted transactions is smaller than the safety transaction utility bound, the high-utility itemsets are directly updated without a database rescan, reducing computational time. Experimental results show that the proposed PRE-HUI-DEL algorithm outperforms existing high utility mining algorithms. When the accumulative total utility in the deleted transactions archives the safety bound of pre-large concept, the database is required to be rescanned for determining the TWU values of the itemsets in case 9. From the conducted experiments, the original database is unnecessary to be rescanned each time, thus reducing the computations compared to the traditional two-phase approach and the FUP-HUI-DEL algorithm.