Negative and Positive Association Rules Mining from Text Using Frequent and Infrequent Itemsets

Algorithm 3

Given:   supp(𝐴∪𝐵)≥minsupp

If     conf(𝐴⇒𝐵)≥minconf, and

   lift(𝐴⇒𝐵)>1

   then 𝐴⇒𝐵 is a valid positive rule, having required minimum confidence and there is a positive correlation between

   rule items A and B.

Else if      conf(𝐴⇒𝐵)<minconf, and

   lift(𝐴⇒𝐵)<1

   then 𝐴⇒𝐵 is not a valid positive rule having lower than required minimum confidence and there is a negative

   correlation between rule, items A and B. Therefore, we try to generate a negative association rule from itemset 𝐼.

If     conf(𝐴⇒¬𝐵)≥minconf, and

   lift(𝐴⇒¬𝐵)>1

   then 𝐴⇒¬𝐵 is a valid negative rule, having required minimum confidence and there is a positive correlation between

   rule items A and ¬B.