Sampling for Frequent Patterns Select a sample of original database mine frequent patterns within sample using apriori Scan database once to verify frequent itemsets found in sample only borders of closure of frequent patterns are checked Example: check abcd instead of ab ac,., ei Scan database again to find missed frequent patterns H. Toivonen Sampling large databases for association rules. In VLDB96 February 4, 2021 Data Mining: Concepts and Techniques 22February 4, 2021 Data Mining: Concepts and Techniques 22 Sampling for Frequent Patterns ◼ Select a sample of original database, mine frequent patterns within sample using Apriori ◼ Scan database once to verify frequent itemsets found in sample, only borders of closure of frequent patterns are checked ◼ Example: check abcd instead of ab, ac, …, etc. ◼ Scan database again to find missed frequent patterns ◼ H. Toivonen. Sampling large databases for association rules. In VLDB’96