Social Network Analysis

After three lectures introducing SNA (Social Network Analysis), I got an overall understanding on SNA in social networking. SNA is very important in engineering community. You will never know how closed the relationship is between the reality and SNA.

Social Network Analysis is the study of the pattern of interaction between actors. A social network is a group of collaborating individuals or entities that are related to each other, and in SNA, Social Network is formally defined as a set of social actors, or nodes, members that are connected by one or more types of relations.

I learned a lot of concepts from the SNA lectures, such as Centrality and Prestige, these words are very easy to understand for their literal meanings. But how can we relate them with the mathematical problems? It's really an interesting topic.

In SNA, Centrality can be studied with undirected or directed graphs (Directed graphs can also be described as digraphs.) while Prestige can only be studied with directed graphs. The most impressive description by Professor Rosanna Chan was that being an actor with prestige, it doesn't mean you have to give out a lot of choices, but only need to receive a great deal of choices, and then you can be called to have prestige. I can give an example to make everyone know better about this concept. 

This is a sociogram showing the interactions of the students in the IEMS5720 blogosphere. As you can see, Su Jing and Helei Cui are both the prominent actors who are extensively involved in the relationships with other students, that means they have much more ties with others, if you want to know more people, the access to their blog is a good choice, no one would choose the isolated ones in the picture as you can access to nobody else except the blog writer himself. So, Su Jing and Helei Cui can both be called the actors with high centrality because they have most ties with others and centrality doesn't care the directions. They are all recognized by others as a major channel of relational information. However, if you want to know who is the actor with highest prestige, you can't only count the ties on the picture, but have to pay attention to the arrows. It is apparent that Su Jing is the person who have the highest prestige. I can prove to you through some other pictures.  

For her one blog, she soon received 10 comments from our classmates while only one comment the other student received. And also you can see, even if she didn't reply to them, she still received a lot of comments, that means she has prestige. Maybe because her former blogs were attractive and soon other students got to know this and they all went to read her blogs.

And then let's see the relationships between some centralized or decentralized networks and the mathematical formulas.

 

If we assume CA(ni) is an actor centrality index, CA(n*) is the largest among CA(ni), the whole actors count g.

Then the general centralization index is

There are three types of centrality, Degree, Closeness, and Betweenness.

Degree centrality is the sum of all others actors who are directly connected to the actor in concern,

Closeness represents the mean of the geodesic distances between some particular node and all other nodes connected with in. The group closeness centralization measures the overall level of closeness in a network, and the group closeness can be expressed as:

Betweenness Centrality means the number of times a node connects pairs od other nodes, who otherwise would not be able to reach one another.

I don't mean to express clearly the difference among them. But I want to point out the common features of Centrality.

 The left network is called star and the right one is a circle.

According to the given formulas, we can get the answers that CD=CC=CB=1 for the star and CD=CC=CB=0 for the circle.

What does it mean? As I have mentioned above, these two are all networks, the star is called the centralized network and the circle is called the decentralized network.

CD=CC=CB=0 means that all actors have exactly the same centrality index, which is obvious from the circle, that's why it's called decentralized network.

CD=CC=CB=1 means that one actor completely dominate or overshadow the other actors, which is exactly the central point in the star network. And so it's called centralized network.

You can know every network's centrality through computing with these formulas, it doesn't matter if the networks are too complicated, the formulas can help you.

SNA is so interesting and full of knowledge that I am now eager to learn more in the near coming lectures.

Two Class Activities Reflecting Epistemic Aims

In the last two lectures,we learned knowledge about communication and social behaviors on the internet.We got to know the concept of group,the difference between cooperation and collaboration and the theory of knowledge-----Epistemology.

We took an active part in the class activities which led us to know more about the relationship between epistemic aims and the size of the participants-----individual and group.

We went through two parts in this activity,which is Class Activity One and Class Activity Two.

In Class Activity One-A, we were required to read an article and answered two questions. The answers were highlighted in the document so as to convenient the next activity.

The article is about social cloud computing.As the first part was to be finished individually and we were given only limited time,I quickly scanned the whole article and noted some key words and eventually answered the questions as followed.

Q1: What is the definition of Social Cloud?
　 A Social Cloud is a resource and service sharing framework utilizing relationships established between members of a social network.
　　　

Q2: What are the possible applications of a Social Cloud?
　　1.A Social Computation Cloud.
　　2.A Social Storage Cloud.
　　3.A Social Collaborative Cloud.

　　4.A Social Cloud for public Science.
　　5.An Enterprise Social Cloud.
　　　
Q3: What strategies you have adopted in answering the above questions?

At the first time of reading this article,my only goal is to answer these two questions correctly.So I hardly had any deep reading.As to the first question,my aim was to find the definition of Social Cloud,so when I came to the sentence that "We now define a Social Cloud explicitly as", I knew that the next paragraph would definitely be the correct answer.

As to the second question,I knew my aim was to find several types of application of a Social Cloud.So when I read that "the point of difference of  a Social Cloud is that applications can also leverage the relationships between users to deliver shared asymmetric services---leading to several potential Social Cloud application scenarios:" I knew the answer was coming. Meanwhile, the article has clear layout,so I quickly underlined the five kinds of applications listed by the author.
　　

My strategy was just to find the key words.Like the words "definition","Social Cloud","application",and then I found the corresponding words like "define","leading to","several","applications" in the article. Finally I located the answers.
　　

As I just quickly went through the article, I didn't know much more about the main idea of this article.My only aim was to get the correct answers of the two questions.So I can't describe this as a kind of understanding, and it's only some sort of knowledge.Because the answers are disconnected while understanding means that you can fit all information together.
　　　
When I read the Class Activity One-B,I came to consider something.

Q1: Do you have any critiques against this article? What is its shortcomings?
　　

After a relatively more careful reading,I found the article's layout was not so clear.As to the first

question.The paragraph of my answer was not all-inclusive,we can hardly understand what is the resource and service,and then came the sentence explaining that the resources exchanged need not be symmetric and can represent vastly different capabilities.Then, I knew much more about the definition of social cloud,and further more information can help you to understand if you read the related part of this article.
　　

As to the second question,I have some doubt that why the application scenarios were classified into these five aspects.While A Social Cloud for Public Science's explanation is somehow related to computing, why it can't be concluded into the Social Computation Cloud part? Since there is an Enterprise Social Could,.why there doesn't exist any other kind of social cloud?
   
Q2: What cognitive processes have you gone through at:
　　(1) cognition level
　　(2) metacognition level
　　(3) epistemic cognition level ?

For the class activity one-A, I think I was in the cognition level, just acquiring knowledge as I thought was definitely right.And then it was proved by fact the the first time's answers were right.
　　

After finishing the activity one-B, I reached the metacognition level, I tried my best to fit all information together, and made some connection.And at last, I still raised some questions about this article.

When we came to the group work---Class Activity Two, I think it is the epistemic cognition level.
　　　
In Activity Two, we were required to copy and paste the article to Google Drive and open it as a Google Docs.By commenting and discussing on a group's Google Docs, we got to understand more about this article and the questions.Finally, the submission of our work result was full of our visions, other group members had additional comments ,others pointed out the key words which helped us to understand the whole article.

After activity two,there are several questions waiting to be answered.

Q1: What was the epistemic aims in (1) Class Activity One(individual work) and (2) Class Activity Two(group work)? Is there any change in epistemic aim?If so,why did you change

your aims?

To answer this question, I should first know the content about the epistemic aims.
There are different types of epistemic aims.
----to acquire true,justified beliefs (liberal believers).
----to avoid false beliefs (conservative believers).
----adopt minimally justified belief.
----Understanding.
----Explanations.
In Class Activity One-A, I was to acquire true,justified belief through individual work.In Class Activity One-B, I was to avoid false beliefs.

In Class Activity Two, we aimed to adopt minimally justified belief and eventually understand it and then submit the explanation we could give.

We were changing our epistemic aims from shallow to deep,which I think it attributes to the group discussion and collaboration.Everyone gave out some improvable ideas,and the ideas were all diversified.Thus, it was a process of building knowledge.The discussion was a problem based discussion instead of assimilation.Everyone was active in the activity,many group members raised the thought like "I suppose""I wonder why",the more the participants engage in problem-based discussions,the more effective is the knowledge co-construction.This why we soon covered all epistemic aims and reached the epistemic cognition level.

Q2: Is there any differences in terms of individual and group epistemic cognition,how?

As epistemic cognition is the highest level of building knowledge.It involves the communication with others and justification about the main idea.People share their own ideas with each others and rise above them to reach the goal of knowledge advancement.They learn from each other and discuss the issue with a goal to produce new knowledge through this learning process.However,for individual epistemic cognition,we just consider things in our own mind, not ensuring its comprehensiveness and can't reach a very high-level summative evaluation,which is a very large difference from group epistemic cognition.

Q3: How did you approach to the problem individually and in group,respectively?
　 Is there any differences in the processes involved?

For my individual work, I have described clearly as to my approach and the processes. And for our group work,expressing our own ideas, avoiding the false answers,raising more diversified thoughts and minimizing our conclusion were the major processes.

At last, I want to share more after these two activities.I think google docs is really a good tool for us to communicate with each other, which definitely enhance the collaboration among us.

Before this activity, I never really got to know this tool, but now, I do really appreciate its function to collaboration.

Google docs is a web-based word processing and spreadsheet program which increases collaboration efficiency.With which we can put the document on to the web and others in the team can do the real-time online document editing and revising.We don't need to send several copies to every member in this group and got several copies back anymore, and also don't need the labor force to integrate all points of view once again.When one is revising the document,he can see others' editing at the same time, and the system will

automatically save the amendment each time so that you can see who made what changes at any time in the past node and resume to the state as you want.

In this social network,useful tools and services are of great support to communication and collaboration.