斯坦福-随机图模型-week3.3_-阿里云开发者社区

开发者社区> IoT> 正文

斯坦福-随机图模型-week3.3_

简介: title: 斯坦福-随机图模型-week3.3 tags: note notebook: 6- 英文课程-9-Probabilistic Graphical Models 1: Representation --- 斯坦福-随机图模型-week3.

title: 斯坦福-随机图模型-week3.3
tags: note
notebook: 6- 英文课程-9-Probabilistic Graphical Models 1: Representation
---

斯坦福-随机图模型-week3.3

习题

1. Question 1

I-Maps. Graph G (shown below) is a perfect I-map for distribution P, i.e. I(G)=I(P). Which of the other graphs is an I-map (not necessarily a perfect map) for P?

III

Correct 
I isn't because it has the extra independence (A⊥C).

II has the extra independence relation (B⊥C∣D) (among others).

III has no extra independencies. In fact, it has fewer independencies, but the definition of I-map allows for this.

II and III

I

I and II

Question 2

I-Equivalence. In the figure below, graph G is I-equivalent to which other graph(s)?

I

Correct 
II, III, and IV all have extra independencies.

III

None of the above

I and III

Question 3

*I-Equivalence. Let Bayesian network G be a simple directed chain X1→X2→...→Xn for some number n. How many Bayesian networks are I-equivalent to G including G itself?

n

Correct 
The chain X1←...←Xi→...→Xn is I-equivalent, where i can be 2 through n (when i=n, all arrows point left). Thus, there are n−1 I-equivalent networks like this. Including the original network makes n.

2n

n−1

n!

版权声明:本文首发在云栖社区,遵循云栖社区版权声明:本文内容由互联网用户自发贡献,版权归用户作者所有,云栖社区不为本文内容承担相关法律责任。云栖社区已升级为阿里云开发者社区。如果您发现本文中有涉嫌抄袭的内容,欢迎发送邮件至:developer2020@service.aliyun.com 进行举报,并提供相关证据,一经查实,阿里云开发者社区将协助删除涉嫌侵权内容。

分享:
IoT
使用钉钉扫一扫加入圈子
+ 订阅

物联网软硬件开发者一站式基地

其他文章