Consider the
Bayesian network (BN) from
Adaptation tutorial. Figure 1
shows the current distribution probability for the net.
|
| Figure
1: Current Distribution Probabilities |
Now go back to
"edit mode" and set all the conditional distribution
probability to 1 except "Tuberculosis or cancer" node.
Switch back to "run mode" and push
"EM-Learning" icon. The EM-Learning icon is shown in
figure 2.
|
| Figure
2: The EM-Learning Icon |
When the icon is
pushed the EM learning window appears. Note that the field
"Convergence threshold" response to the log-likelihood.
Push "Select File" button and choose a file from which
the conditional distribution probabilities must be computed. When
the file is selected the "OK" button appears as shown in
figure 3.
|
| Figure
3: The EM-Learning Window |
Pushing the
"OK" button starts the EM-algorithm. Based on the case
set given in the file the EM-algorithm computes the conditional
distribution probability for each node. Figure 4 shows the new
conditional distribution probability based on asia.dat file.
|
| Figure
4: The New Conditional Distribution Probabilities |