[SOUND] The first thing we want to discuss is, The Limitation of the Support Confidence Framework. As we know, pattern mining may generate a large number of rules but not all of the patterns and rules generated are interesting. In general we can classify the interesting measures into two classes, objective versus subjective. For objective measure like support, confidence, correlation are defined by mathematical formulas, not change from person to to person. But the subjective measure may change from person to person, because one man's trash could be another man's treasure. So the first thing, is we may want a user to say, what do you like to see? So it's query based. Another thing is we may base on user's knowledge base, try to mine something unexpected, fresh or recent. Or we can map patterns and rules into two-dimensional space, let user to interactively pick some interesting things. So we know we have support and confidence as two interestingness measures in association rules. So we may be careful about this, because not all the strong support and confidence rules are interesting. For example, take the following table, a 2-way contingency table, to look at this to see how to interpret things we found. For example, in this table, 400 out of 1000 students play basketball and eating cereal, but 200 students, they play basketball but they may not eat cereal. In this one, you may derive association rule like this. Playing basketball implies eating cereal. You probably will get a 40% support because it's 400 over 1,000. You will get two thirds of the confidence because you get 400 over 600. So this is pretty high support and confidence. Is this really interesting? Let me try another rule regenerated. Actually you will see, if we say not playing basketball, eating cereal. You will see not playing basketball is 35%, with the confidence even higher, because they have 350 eating cereal out of 400 people. So this one is even higher. So, if you recommend these two rules to the cereal company, they will get confused. They'll say, the first rule say that I better give some free basketball because if they play basketball, eating cereal. The second rule say I better take their basketball away, because if they do not play basketball they actually eat cereal even more. Which one is right? Let's examine it. [MUSIC]