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Density Estimation using Series Expansion

Last "non-parametric" technique (although very parametric)

Write $ p(x) = sum(cj*fj(x)) $ where {$ fj's $} are pre-determined class of functions $ =sum(cj*fj(x)) $

Monomials. E.g. Taylor expansion about Xo in 1-D.

Decision Trees

Reference DHS Chapter 8 Decision tree is one of the most powerful method for classification, because it simplifies the classification by dividing the problem into subproblems. A sample decision tree and training set from J.R. Quinlan (Induction of Decision Trees) can be given as follows:

Decision OldKiwi.jpg

Trainset OldKiwi.jpg

The decision tree separates two classes. First class is "play tennis" and the second one is "do not play tennis". The decision tree tries to find the answer by asking several question. The purpose is to generate decision tree using the training data.

Instead of asking a complicated question $ g(x) >= 0 or <0 $

The idea: Ask a series of simple questions following a tree structure (linear 1-D).

ECE662 lect20 tree1 OldKiwi.jpg ECE662 lect20 tree2 OldKiwi.jpg


Lectures

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