Conclusion of Lecture 20
   - Machine learning algorithms can be used to learn virtually
       everything.
 
   - They depend on training data, so the system gets better with
       more data.
 
   - The more you know about the data, the easier it is to build 
       a system, and the better the result.
 
   - Many techniques are applicable to each problem.
 
   - No technique is best for every problem.
 
   - The reading for this week was flexible.  You needed to pick a
       paper on Machine Learning.  
 
   - There is no reading for next week.