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EM Algorithm Applet [3 P]

Go to Olivier Michel's applet Gaussian Mixture Model EM Algorithm at
http://lcn.epfl.ch/tutorial/english/gaussian/html/index.html and answer questions 1-6 [1 P]. Additionally do the following:

a)
[1 P]

Create points from two intersecting lines and run the algorithm with option LineMix and 2 clusters. Click repeatedly on EM 1 Step to run the algorithm. Repeat this experiment with different cutting angles of the lines and analyze if this has an effect on the number of iterations until convergence.

b)
[1 P]

Create points in a ring around the center with the button RingPts. Try to fit a mixture of lines model (with EM Run) to this distribution and analyze what happens when you change the number of lines. Do the same experiment with mixtures of Gaussians and describe what you find.



Haeusler Stefan 2007-12-03