17 Bayes Nets 1

https://www.dropbox.com/s/rs9n16yh9jk6tfo/CSE%20511A%20Lecture%2016%20--%20Bayes%20Nets.pptx?dl=0

贝叶斯网是一种反映joint distribution的方式。

试想我们有10个variables, 那么要展示他们的FD就需要2^10行（assuming the domain of these variables are true of false）.However， 很多variables之间如果是independent的话，我们就不需要这个2^10的表。我们可以用bayes net去反映着这个FD。

Bayes net的好处：

1)不用这么大的FD

2） 更好的展示variable之间的关系

Bayes net的坏处：

1）not every bn can represent every FD

接下来我们开始学习bayes net

1）independence和conditional independence的知识；

2）Bayes net的基本样子；

3） Bayes net的概率推论及其例子；

Independence

Conditional Independence

Conditional Independence and Chain Rule

Bayes Net and Chain rule and Conditional Independence

Bayes Nets

• A new way to represent Joint Distribution.

• Reduce the number and size of the joint distribution.

• And easy to understand the relationship among the variables.

Bayes Net Semantics

Examples

summary

next course

By just BN graph, what can we infer from it.

How to answer miracle query