Mining Frequent Itemsets in Large Data Warehouses: A Novel Approach Proposed for Sparse Data Sets

Proposing efficient techniques for discovery of useful information and valuable knowledge from very large databases and data warehouses has attracted the attention of many researchers in the field of data mining. The wellknown Association Rule Mining (ARM) algorithm, Apriori, searches for frequent itemsets (i.e., set of items with an acceptable support) by scanning the whole database repeatedly to count the frequency of each candidate itemset. Most of the methods proposed to improve the efficiency of the Apriori algorithm attempt to count the frequency of each itemset without re-scanning the database. However, these methods rarely propose any solution to reduce the complexity of the inevitable enumerations that are inherited within the problem. In this paper, we propose a new algorithm for mining frequent itemsets and also association rules. The algorithm computes the frequency of itemsets in an efficient manner. Only a single scan of the database is required in this algorithm. The data is encoded into a compressed form and stored in main memory within a suitable data structure. The proposed algorithm works in an iterative manner, and in each iteration, the time required to measure the frequency of an itemset is reduced further (i.e., checking the frequency of ndimensional candidate itemsets is much faster than those of n-1 dimensions). The efficiency of our algorithm is evaluated using artificial and real-life datasets. Experimental results indicate that our algorithm is more efficient than existing algorithms.