Assignment2_answer

Assignment2_answer - Model Answer for Assignment 2 1 Step...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Model Answer for Assignment 2 1 Step 1: Find all the confident rules for a given minimum confidence. ( Given a minimum confidence minconf, a rule is confident if conf( x→c ) ≧ minconf, where conf( x→c ) is the confidence of rule x→c ) Step 2: From association rules to a classifier Let C denote the set of condent rules plus the default rule, Ø c, where c is the majority class in relational table T. Let size(r) denote the number of values in rule r, and let lhs(r) denote the left-hand side of r. We assume that the values in a rule are ordered lexicographically. Similarly, rules can be ordered lexicographically. For example, rule x,y 1 precedes rule y 0 lexicographically. Binary relations: Consider two rules r and r’ in C. We say that r is ranked higher than r’ written as r r’, if the following conditions hold: conf(r) > conf(r’); or if conf(r) = conf(r’), but sup(r) > sup(r’); or if sup(r) = sup(r’), but size(r) < size(r’); or if size(r) = size(r’), but r precedes r’ in the lexicographical order of rules. We say that r is more general than r’ (or r’ is more special than r), written r ’, if lhs(r) lhs(r’). R p G p r CF Principle: If there are choices, the rule of the highest rank has the priority. e can use the MCF principle to resolve the conflict in covering a case: the covering edundant rules: Arule r in C is redundant if there is some rule r’ in C that is more ith only non-redundant rules, we can show that left-hand sides of rules are distinct, tep 3: Pruning the Classifier , the MCF principle implies that the highest ranked d DT: Consider a non-default rule r in C. The parent of r is the rule in C that is more M W rule of a given case is the rule that matches the case and has the highest possible rank. R general and ranked higher than r, that is, r’ p r and r’ p r G R W and thus, that the generalization relationship is a lattice over left-hand sides of rules.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 7

Assignment2_answer - Model Answer for Assignment 2 1 Step...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online