What, Why, HOW

Lately I've gone through roughly 15 books about social psychology, crowd behavior, group emotions contagion, irrationality, and topics involving people in the society, don't panic, just for fun, no special academic interest really. It seems to me that they can be either categorized as theoretical or empirical, easy to understand right? For theoretical books, they are more like textbooks, emphasizing on definitions, principles and some sort of related examples, yuck. While for empirical thesis, more experiment-oriented, more human factors involved, and more lively. The approaches scientist/ psychologists adopt to get clear of a question is actually extremely similar: background - theory proposal - experiment - result - conclusion. It's fun to watch people acting as candidates, being tested, sometimes not aware, and giving out unexpected results at the end. Here strongly recommend Dan Ariely's books. What a fun guy!

These book enlightened me about the reason to carry out studies, the utility to define new stuff, the reason of existence of all the experiments and theories. Because if they serve only to stuff the bookshelf and can't be utilized to do anything, then they are purely junk.

So here it go. I want to concisely evaluate the utility of several factors that we calculate for SNA. I've put all stuff in my own words, so they are really lifelike and trivial...So what do they describe, and why them?

HOW -- lecture notes thanks... = =

WHAT:
Let's see some SNA analysis key factors:

Degree centrality:
the more neighbor an actor has, the easier it is for him to catch new information
Closeness centrality:
the smaller the distance, the larger the speed to spread information
Betweenness centrality:
the number of times an actor acts as a bridge along the shortest path between two other actors -- the participation of the actor during high-efficiency information propagation (since only shortest lines are counted)

WHY:
I always believe things exist for a reason, and the reason why these factor exist in the place of others is their unique irreplaceable usage.

These three factors describe the connectivity, distance and intermediate function of an entity. Imagine the flow of information: income from a neighbor->outcome to all neighbor->propagate. That's correspondingly related to degree, betweenness and closeness.  Degree stands for the incoming power, betweenness describes the probability of occurence of such an action, and closeness gives the flow of information, which is a continuous process.

No matter the object is an actor or a group as a whole (as when a group is treated as a whole, it's again an actor), these three factors ideally define the life cycle of information propagation. And why not other factors like "location", "traffic load", etc? Because the fundamental structure of a network is defined by the connectivity and relationship between people (that's why we call it social network).

So here's my belief: they exist to serve functions. And there's no need to panic about the dirty maths, since after all, it's just maths. What's lying behind is the true thing that matters.

HOW
Finally I plan to go back to where I started with. It seems that we've learnt many theoretical ideas in the class. Even given some examples, it still appears quite distant from us. So to fully comprehend the idea behind SNA as well as to utilize SNA, we should design our own experiments, implement our own analysis systems to really get to know social networking. Maths is maths if left alone, however maths is everything if combined with real life cases. That's really why we need SNA and how SNA can help us mine data, grab the essence of the trends of social networks, and come up with brand-new solutions.

Appreciation of Sociomatrix

A matrix X of size g×g is defined to describe the connectivity inside the group, inside which an entry x_ij indicates the existence of a directional link from i to j. Such a matrix summarizes the whole status of the group and is sufficient to include all the information needed to describe a group. One example can be:

Here the power of X is 1, so each non-zero entry indicates a link of length 1. For example, x₁₂=x₁₅=1, the physical meaning is that node 1 has an out degree of 2, pointing to node 2 and node 5 once each.

By taking the n^th power (n < g) of X, say n=3, we obtain:

In this case, n=3 gives all the possible paths of length 3 among the existing nodes. The intensity of a certain entry gives the number of different paths.

Take =3 for example, this means from node 1 to node 3, there exist three paths of length 3, they each are:

Node 1 – Node 2 – Node 6 – Node 2	Node 1 – Node 2 – Node 3 – Node 2
Node 1 – Node 5 – Node 6 – Node 2

And this process exhausts all the possibilities.

This matrix representation method is concise and informative for either visual observation or statistics analysis. From my point of view, adopting matrices has advantages as follow:
1. Standardized computation.
By applying multiplication to the original matrix, we can easily obtain different level of information without introducing much computation. This way of information processing also allow computers to calculate answers in a much easier way, so that codes and programs can be as concise as possible.

2. Fixed structure of matrices
The format is still concise and matrix remains the same dimension and size as the original one. Such consistency can keep the systems function properly.

3. Easier reuse
This method is not the final goal of a topic. It's just a method used to simply other problems.
In the form of matrices, this calculation method can be easily implemented and encapsulated. In this way, black box reuse is possible, so that users don't necessarily need to know the exact calculation methodologies behind it, instead the numbers say for themselves, and should be enough to explain problems.

4. Can you guys think of more advantages? :)

Reflection on Lecture 6

- 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?

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

For activity one, the aim is to obtain the explicit or implicit answer from the given text, possibly by extracting, in-depth thinking and paraphrasing, depending on the structure of the text itself. The process would be: glance to grip the major points; read thoroughly; search for answers in a detailed focused way. This scheme of study helps us generally understand the passage as well as be able to track details.

Comparatively, for activity two, since we already have formed our own understanding, the epistemic aim switches to a higher level – reorganization of concepts through idea exchange. By observing others’ learning outcome and format of study, we are able to reflect thoughts from a different aspect, which we don’t have in the first place. This process enables us to refine not only the answer to the question itself, but also the way of thinking, the presentation of ideas, and some higher level cognitive factors.

This smooth change is due the steady growth in understanding of the problem, as various opinions from various parties can represent different ways of thinking. Such differences can enlighten the whole group.

2. Is there any difference in terms of individual and group epistemic cognition, how?

My answer would be yes. Individuals rely on their personal experiences to solve problems with some structured ways, and the focus is strictly on the question itself. No feedback or opinion from a third party will come to complete the possibly flawed perception. This kind of epistemic cognition relies more on contextual refinement without the help of others. However group discussion and collaboration highlights the dynamic combination of various thoughts: how they conflict, why they exist, how to solve, etc. This people interaction is a new platform of learning and obtaining fresh ideas to solve specific questions. Usually the spark between people and the art of coordination is the key element for the finalization of an answer.