2. The research relatedThe problem of exploitation of useful higher volumes due to Yao and Hamilton proposed in 2004 [4]. The authors propose the UMining algorithm based on block on (upper bound) of useful level to harness the HUI. Then UMining-H, a heuristic of UMining due to changing the way computer block above useful to sniper candidates. Both UMining and UMining-H capable trimmed the wrong the HUI. In 2005, Liu and colleagues propose a block on the new TWU (Transaction Weighted Utilization) for the exploitation of HUI [6]. TWU of the itemset properties reduced closure agreement should be able to rely on it to sniper candidates. So, the author proposed two-phase algorithm based on the TWU to sniper candidates. Two-Phase is divided into two phases include (1) exploiting all the itemset contains greater or equal to the TWU minutil (the minimum threshold is due to the user put in) (2) From the episode the itemset contains TWU minutil agreement, two-phase scan database (DATABASE) to calculate the useful degrees of each itemset, and filter out the itemset has a useful minutil agreement. Due to the two-phase spend quite a lot of times the scan DATABASE and many candidates in phase 1, no effect on the DATABASE.
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