epgy:ai13:day_8

**Question:** Suppose you're on a game show, and you're given the choice of three doors: Behind one door is a car; behind the others, goats. You pick a door, say No. 1, and the host, who knows what's behind the doors, opens another door, say No. 3, which has a goat. He then says to you, “Do you want to pick door No. 2?” Is it to your advantage to switch your choice?

http://www.youtube.com/watch?v=QX_oy9614HQ

- 10:00 Tracy Ballinger, UC Santa Cruz
- 11:00 Dave Mark, Intrinsic Algorithm

Cyber Stalking Assignments

- AI Engineer - AI Scientist

Research Clusters - 20 minutes

**Red and Black Review**

Probability Range

- 0 ≤ P(A) ≤ 1

Rule of Addition

- P(A∪B) = P(A) + P(B) - P(A∩B)

Disjoint Events Events A and B are disjoint iff

- P(A∩B) = 0

Conditional Probability

- P(A | B) = P(A∩B) / P(B)

True Bayesians actually consider conditional probabilities as more basic than joint probabilities . It is easy to define P(A|B) without reference to the joint probability P(A,B). To see this note that we can rearrange the conditional probability formula to get:

P(A|B) P(B) = P(A,B)

but by symmetry we can also get:

P(B|A) P(A) = P(A,B)

It follows that:

which is the so-called Bayes Rule.

http://en.wikipedia.org/wiki/Bayesian_network

Remember: Finite State Machines? - Deterministic

Bayes Nets: http://www.idi.ntnu.no/~dingsoyr/diploma/node18.html

**Building a k-D tree**

Application: 3-D graphics

Algorithm BuildKDTree (S, depth) input: a set of points S, the current depth depth output: the root of a kD-tree storing S if S contains only one point then return a leaf storing this point else if depth is even then Split S into 2 subsets with a vertical line L through the median x-coord else Split, 2 subsets with a horizontal line v_left <- BuildKDTree (S1, depth+1) v_right <- BuildKDTree (S2, depth+1) v <- L return v

**Data Classification**

Application: Separating Audio Tracks

Audio ML: http://cs229.weebly.com/index.html

**ConceptNet**

Application: Language

Language ML:

- 20Q Wordnet Conceptnet
- Argument Champion
- Restaurant Game

Decision Trees

/soe/sherol/.html/teaching/data/pages/epgy/ai13/day_8.txt · Last modified: 2013/07/26 12:22 by ffpaladin