• Title/Summary/Keyword: 직접 해쉬 테이블

Search Result 1, Processing Time 0.013 seconds

Improvement of DHP Association Rules Algorithm for Perfect Hashing (완전해싱을 위한 DHP 연관 규칙 탐사 알고리즘의 개선 방안)

  • 이형봉
    • Journal of KIISE:Databases
    • /
    • v.31 no.2
    • /
    • pp.91-98
    • /
    • 2004
  • DHP mining association rules algorithm maintains previously independent direct hash table to reduce the sire of hash tree containing the frequency number of each candidate large itemset. It performs pruning by using the direct hash table when the hash tree is constructed. The mort large the size of direct hash table increases, the higher the effort of pruning becomes. Especially, the effect of pruning in phase 2 which generate 2-large itemsets is so high that it dominates the overall performance of DHP algorithm. So, following the speedy trends of producing VLM(Very Large Memory) systems, extreme increment of direct hash table size is being tried and one of those trials is perfect hash table in phase 2. In case of using perfect hash table in phase 2, we found that some rearrangement of DHP algorithm got about 20% performance improvement compared to simply |H$_2$| reconfigured DHP algorithm. In this paper, we examine the feasibility of perfect hash table in phase 2 and propose PHP algorithm, a rearranged DHP algorithm, which uses the characteristics of perfect hash table sufficiently, then make an analysis on the results in experimental environment.