Practical Applications of Data Mining

60 Chapter 2 assoCiation rules

called employment, a rule “if occupation is medical doctor, then salary is high”

is derived. In this rule, “medical doctor” is a domain element of attribute

occupation and “high” is the concept specified in the DCH for the attribute

salary. Hence, a semantic association from “Occupation is medical doctor” to

“Salary is high” can be derived.

2.6.2 Generalization Algorithm

Generalization is necessary when there are a large number of distinct values

for each attribute in a relation. When each attribute contains a large number

of distinct values, the derived rules from the relation may not be useful be-

cause the rules may be complex or the rules may characterize few tuples. To

derive compact rules from reduced ...