Post 3 - SNA

1. Social Network Analysis is the study of pattern of interaction between actors
• Focus on the social actor and the relationship between the actors
• Each participant in the community is called an actor and depicted as a node
• Valued relations between actors are depicted as links, or ties, either directed or undirected, between the corresponding nodes
2.   

Undirected graph
It is a undirected graph.


Geodesic Distance

	Alice	Bob	Carol	David	Eva
Alice	-	1	1	1	2
Bob	1	-	2	1	2
Carol	1	2	-	1	2
David	1	1	1	-	1
Eva	2	2	2	1	-

Cutpoint
David is the cutpoint of the network. If David is removed, the connection between Eva to Alice,Bob,Carol would be cut.

Bridge
The bridge is the connection between David-Eva. It it is removed, Eva would be isolated.

Density
2L / G(G-1) = 2*6 / (5*4) =  0.6

Degree Centrality:
Alice - 3,  Bob - 2,  Carol - 2,  David - 4, Eva - 1

Group Degree Centrality:
(1 + 2 + 2 + 0 + 3) / (4 * 3) = 0.67

Closeness Centrality: 
Alice - 0.2,  Bob - 0.167,  Carol - 0.167,  David - 0.25,  Eva - 0.143

Group Closeness Centrality:
= [(0.25 – 0.2) + (0.25-0.167) + (0.25 – 0.167) + (0.25 – 0.143)] / {[(5-1)(5-2)]/(2*5-3)}
= 0.189

Betweeness Centrality:  
Alice - 1/2 = 0.5
Bob - 0
Carol - 0
David - 1/2 + 1 + 1 + 1 = 3.5 (B-C, B-E, C-E, A-E)
Eva - 0

Group Betweeness  Centralization: 
=2 * [(3.5 - 0.5) + 3.5 + 3.5 + 3.5] / [(5-1)^2 * (5-2)]
= 0.5625

c)

When we use the degree, closeness and group centralization index to measure the centralization of the network,  we find that the normalized index is about 0.5, that means the whole network is connected as a fair connection. David has the highest centralization index. It show that David is the most influential person in the network.

If the 5 students are to be coordinated, David would be suitable for assigning a post of Captain. On the other side, Eva is only connected to David and she can only obtain information from him. Therefore, a new connection is to be suggested to Eva to Alice/Bob/Carol. Then all of the centrality index would be increased.

Post 2 - Learning Progress & Recent Social networking topic

In the last few weeks, I have about the recent development of the social networking. Before I study this course, I just know the most popular social networking sites such as Facebook, twitter and so on. And I didn't know there are many other popular and useful social networking sites with other purpose. Also, I was amazed about the method for analyzing the social networking by using the graph theory.


Week 4


Blogosphere, Information Sharing and Cases of Social Marketing

• Blogs
• A good channel for social media marketing
• a good way for company to reach out and build a community with customer and clients
• Social Media Marketing
• A new way of marketing enabled by information sharing
• Social Recommendation
• Direct - Like or recommend after creation or discovery of good content
• Derived - Analysis to generate recommendation like most read and most commented

Week 5

Social Multimedia computing

• Social Multimedia
• The hybrid of multimedia and social media
• supports new types of user interaction
• provides additional context for understanding multimedia content
• Two vies of social mutimedia computing
• Social computing over multimedia
• Social empowered multimedia computing
• Social multimedia examples
• Social multimedia search
• Interactive services and entertainment
• Healthcare

Week 6

Social Network Analysis

• Graphical representation
• Directed and Undirected graph
• Technical Terms
• Dyad, Path
• Cutpoint
• Bridge
• Degree
• Density
• Geodesic Distances
• Clique (N-Clique)
• Plex (K-Plex)
• Centrality
• Degree Centrality
• Closeness Centrality
• Betweenness Centrality