Efficiently mining of skyline frequent-utility patterns

Frequent itemset mining (FIM) is one of the most common data mining techniques, which is based on the analysis of the occurrence frequencies of items in transactions. However, it is inapplicable in real-life situations since customers may purchase several units of the same item and all items may not have the same unit profits. High-utility itemset mining (HUIM) was designed to consider both the quantities and unit profits of items in databases, and has become an emerging and critical research topic in recent decades. The SKYMINE approach was proposed to mine the skyline frequent-utility patterns (SFUPs), by considering both the utility and the occurrence frequencies of items. A SFUP is a non-dominated itemset, where the dominance relationship between itemsets is based on the utility and frequency measures. Mining SFUPs using the SKYMINE algorithm and its (UP)-tree structure requires, however, long execution times. In this paper, we propose a more efficient algorithm named skyline frequency-utility (SFU)-Miner to mine the SFUPs, utilizing the utility-list structure. This latter structure is used to efficiently calculate the actual utilities of itemsets without generating candidates, contrarily to the SKYMINE algorithm and its UP-tree structure. Besides, an array called utility-max (umax) is further developed to keep information about the maximal utility for each occurrence frequency, which can be used to greatly reduce the amount of itemsets considered for directly mining the SFUPs. This property can be used to efficiently find the non-dominated itemsets based on the utility and frequency measures. Substantial experiments have been carried out to evaluate the proposed algorithm's performance. Results have shown that SFU-Miner outperforms the state-of-the-art SKYMINE algorithm for SFUP mining in terms of runtime, memory consumption, number of candidates, and scalability.