2012年11月27日星期二

Calculate Matrix Multiplication in two different method

In today's blog, we will talk about something about Social Network Analysis (SNA). 

Social Network Analysis is the study of the pattern of interaction between actors. In SNA, Social network is generally defined as a set of social actors, or nodes, members that are connected by one or more typrs of relations.

Then let's see a simple social network. To represent the relationship among factors in social network simply and clearly, we use sociogram which is a diagram to represent a social network. For example, take the relation X of Alice, Bob, Carol, and David into consideration. All these four people have their own blog. They would like to comment on others' blogs. Alice comments on Carol and David's blogs. Bob comments on Carol and David's blogs. Carol comments on Alice's blog and David comments on Alice and Bob's blogs. Therefore, we can get a sociogram below as the graphical representation (sociogram) of this simple social network.

We can also represent the ralation X of the simple social network by the sociomatrix X. Where {Alice, Bob, Carol, David}corresponds to {n1, n2, n3, n4}.


As most SNA ignore these "self-choices"elements, this table uses "-" to represent "self-choices". Symbol "0" means one individual does not comment on the others ans symbol "1" means one individual comments on the others.

After mastering how to represent the relationship of a simple social network in sociogram and sociomatrix, we will start to analyse the matrix multiplication using two different method (X multiply X is used as an example in this analysis). The sociogram and the sociomatrix is shown below.


  • The first method
We can use math method to do the matrix multiplication in first way. X multiply X, which means X2 can be calculated according to the equation xij[2]=xikxki (k from 1 to g). We can get X2 represented by socimatrix.



  • The second method
In the second method, we can do the matrix multiplication by sociogram. For instance, according to sociogram, n1 can reach n3 in one way with two steps, so we fill "1" in the first line of the third column. Similarly, n1 can arrive at n6 in two ways with two steps, so we fill "2" in the first line of the six column.
In this way, we can easily deal with the matrix multipliaction using relationship of the factors in the social network.

In general, Xis defined as the matrix product of X times itself, 2 times. This operation can be used to study walk and reachability in SNA. 

These above are the part of SNA I prefer to talk about...  
 






2012年11月6日星期二

How can people work in group through social network?

To get access to the answer of the title, we should know what is a "group" in social networking firstly. A psychology group is any number of people interact with each other, aware of others's exsitance and recognize theirselves in a group. Groups can be divided into different types, such as formal group and informal group. Likewise, group can be divided according to membership.

Group is a structure consists of members who have different roles, status, relations and communication networks and subgroups. How can we perceive the members of the group structure. We can obtain following views. Firstly, In group people have different status, for instance, leader has higher status than others. Secondly, in group   structure, subgroup can be nested within the larger group. Lastly, in group structure, communication can be defined as the process by which an individual transmits information about feelings and ideas to another people of the group.

The social networking sites can be treated as online social environments, providing different social experiences to participants. Social experience model can be classified as:

  • Individual
In this model, every members can have their own environment, they can share their ideas and knowledge to all others in their own domain.

  • Social network
Each user has a select network of direct relationships with other users they can collaborate with.


  • Closed workgroup
A select group of members collaborate on ideas and experiences among themselves within a dedicated space.
  • Visible workgroup
A select group of members collaborate and contribute ideas and experiences within a dedicated space, but they also selectively allow other users to access their infromation.
  • Community
Any member can join te group and contribute, read the information within the dedicated sapce.


  • Mass collaboration
Anyone can contribute to or read the information in the space. Membership is not necessary to contribute. Beyond individual information, the experience aggregates their inputs into collective results.

With the development of the technology, Cloud computing is used in social networking. It is the ability to access a pool of computing resources owned and maintained by a third party via the internet. With it , people can upload the material to the internet, and read the information stored on the internet. People can exchange opinions more efficiently. And the cloud can cover many aspects of the questions we can meet in everyday life.



1.The answer of activity one. 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.
2.What are the possible applications of a Social Cloud?
A Social Computation Cloud/A Social Storage Cloud/A Social Collaborative Cloud/A Social Cloud for Public Science/An Enterprise Social Cloud.
3.The answer of activity two.






























4.Epistemic aim of individual work is find the answer quickly and make sure the answer is correct when I do the problem. But the aim is changed when work in group, we not only work out the answer but also understand why is the answer. When I do the question myself, I read the material given by professor, and search the answer by the Google. In group, we discuss and tell the reason to each other.