4. Data mining
4.1. Association rules
Discovering association rules is an important data mining problem
(Agrawal, Imilienski, & Swami, 1993), and there has been considerable
research on using association rules for data mining
problems. The association rules algorithm is used mainly to determine
the relationships between items or features that occur synchronously
in databases. For instance, during a trip to the
shopping center, if the people who buy item X also buy item Y as
well, there exists a relationship between item X and item Y. Such
information is useful for decision makers. Therefore, the main purpose
of implementing the association rules algorithm is to find
synchronous relationships by analyzing random data and to use
these relationships as a reference for decision-making. The association
rules are defined as follows (Wang, Chuang, Hsu, & Keh,
2004):