2012年4月29日星期日
About online social network security
According to Wikipedia's descriptions about Security service, the conventional security services include Authentication, Access control, Data confidentiality, Data integrity and Non-repudiation.
On the other hand, in the context of OSNs there are three main security objectives: Privacy(which encompasses user profile privacy, communication privacy, message confidentiality and information disclosure), Integrity and Availability.
So as we can see, the privacy of OSNs seems to be more strict due to the more requirements. To ensure communication privacy, authentication must be done first. Information disclosure needs the access control finegrained to the level of each manageable user. Most significantly, all information of users including their participation in the OSN should be hidden in the system in order to ensure a real privacy, which is not mentioned in the conventional security services. Remember the database disclosure of an IT community called CSDN? A large amount of user profiles were available throughout the world soon because CSDN stored them in plaintext in database. This kind of privacy problem is a nightmare in famous OSN.
In terms of integrity, only ensuring data integrity is not enough in OSN. Some problems like bogus accounts or cloned accounts may occur. To solve the problem, OSN has to find ways to ensure the real identity of each registered member. For example, in Renren.com if one claims to be a student of CUHK, then he/she have to prove it by either logging in the website with CUHK's IP address or scaning the student id card for administator's verification.
When it comes to availability, besides availability of data access, message exchange among members has to be available as well. In OSN, as a basic feature, availability has to include robustness against censorship. In this way OSNs are able to ensure user's profile and data published is always available. Using the case of Renren.com again, if any user wants to stop the account, all of his/her data like journals or photos will remain on the server, waiting for possible reuse in the future.
About SNA
SNA is the process and corresponding result of analysis on the relationship and interaction among social network's actors, in my opinion.
Besides the graph
The social network can be described as sociomatrix
From first view I think David is the most influential because he is the only one who connects to all other students. Then I use Betweenness Centrality to solve the problem. Because Betweenness Centrality is a measure of the potential for control as an actor who is high in “betweenness” is able to act as a gatekeeper controlling the flow of resources between the alters that he or she connects. On the other hand, the answer is too simple and obvious if we use Degree Centrality, and closeness is not so significant as betweenness in this case if we use Closeness Centrality. So to judge with Betweenness Centrality is the most appropriate in my mind.
According to the formula
Besides the graph
The social network can be described as sociomatrix
|
|
|
Bob
|
Carol
|
David
|
Eva
|
|
|
-
|
1
|
1
|
1
|
0
|
|
Bob
|
1
|
-
|
0
|
1
|
0
|
|
Carol
|
1
|
0
|
-
|
1
|
0
|
|
David
|
1
|
1
|
1
|
-
|
1
|
|
Eva
|
0
|
0
|
0
|
1
|
-
|
From first view I think David is the most influential because he is the only one who connects to all other students. Then I use Betweenness Centrality to solve the problem. Because Betweenness Centrality is a measure of the potential for control as an actor who is high in “betweenness” is able to act as a gatekeeper controlling the flow of resources between the alters that he or she connects. On the other hand, the answer is too simple and obvious if we use Degree Centrality, and closeness is not so significant as betweenness in this case if we use Closeness Centrality. So to judge with Betweenness Centrality is the most appropriate in my mind.
According to the formula
I obtain the result
|
|
Betweeness
Centrality
|
|
|
0.8
|
|
Bob
|
0
|
|
Carol
|
0
|
|
David
|
0.58
|
|
Eva
|
0
|
And it proves that my previous guess is right. David is the most influential due to his most connections and his significant place to act as gatekeeper.
Brief reflection about social brainstorming
Through the lecture I gradually realize the importance of people's interaction. For example, besides listening to lecturer only, we still need discussions and group projects in almost every course. Why? In my opinion, these activities make a difference by the way of enhancing the learning progress. It is of the same importance as independent study.
This is the reason why I want to talk about social brainstorming. Brainstorming, according to its name, is a storming process inside the brain in order to come up with new ideas. Also, it is the source of innovation. However, to achieve successful brainstorming, one can not just keep thinking all day long, just like writer also need outdoor activities to obtain new ideas. To solve the problem, interaction among people does work.
When our group started the project, I suggested to perform brainstorming and picked up the best one in the end. Unfortunately, none of our ideas seemed to be an innovative one, which delay the project's process. Then I realized only brainstorming among our team members is too limited. Suddenly the concept of social brainstorming came into my mind, after which I post an vote on social network platform and asked what my friends wanted to do most during holidays. Later the result came out and a majority of participators chose to travel. Why not build a professional social platform for traveler? Then the project about building a social platform about travel was launched.
On the platform users can share their experience and feeling about travel, just like I am sharing the experience about studying this course on Blogger.com now. Thanks to these platforms, users' role is turned from content browser only to both browser and creator, which accelerate the progress of Web2.0.
We use social brainstorming to create the platform, and the platform contributes to those who share similar interest and enables their social brainstorming. Hmm, an interesting try.
This is the reason why I want to talk about social brainstorming. Brainstorming, according to its name, is a storming process inside the brain in order to come up with new ideas. Also, it is the source of innovation. However, to achieve successful brainstorming, one can not just keep thinking all day long, just like writer also need outdoor activities to obtain new ideas. To solve the problem, interaction among people does work.
When our group started the project, I suggested to perform brainstorming and picked up the best one in the end. Unfortunately, none of our ideas seemed to be an innovative one, which delay the project's process. Then I realized only brainstorming among our team members is too limited. Suddenly the concept of social brainstorming came into my mind, after which I post an vote on social network platform and asked what my friends wanted to do most during holidays. Later the result came out and a majority of participators chose to travel. Why not build a professional social platform for traveler? Then the project about building a social platform about travel was launched.
On the platform users can share their experience and feeling about travel, just like I am sharing the experience about studying this course on Blogger.com now. Thanks to these platforms, users' role is turned from content browser only to both browser and creator, which accelerate the progress of Web2.0.
We use social brainstorming to create the platform, and the platform contributes to those who share similar interest and enables their social brainstorming. Hmm, an interesting try.
2012年4月28日星期六
Importance of deeper level about cognition
After attending 3 lectures about social networking, I found the course worth choosing in this term. The film <The Social Network>(2010) I have saw previously gave me an deep impression about how Facebook was built. However, due to the 2 hours' length limitation of film, details about social network are not mentioned. Then the course give me suck a chance to learn deeper.
As an engineering student, I have seldom read the books about psychology and don't know the transferring process of human knowledge. But now I learn the Stage Theory. The external stimulus needs to be processed initially into short-term memory, and finally into long-term memory through encoding. It causes my attention to the process of studying. No matter in childhood, high school or university, we are given a proper amount of homework/assignment besides attending class/lecture. The aim is to turn the short-term memory into long-term memory. Otherwise, we will forget about it soon and it is just a waste of time.
The 3 levels about cognition also impressed me. Actually, most of what I have thought about everyday news just stays in the first level. I just know it, and then go on knowing the next one. To make our mind further engaged, should we slow the steps to spend some time on thinking about that piece of news deeper? The answer is no in the past for me because in my mind it is useless. However, after research on the case about "KONY 2012", I understand that it is worthwhile to update our attitude to at least second level to every news, or the ones who don't know the truth are likely to be mislead under some evil purpose.
For example, hundreds of thousands of people online support US government to send military into Uganda in order to capture KONY. However, after deeper investigation and consideration, it is another invade aiming for petroleum in my opinion, just like Afghan's case.
Even not helpful, don't support the evil, only when we improve our cognition's level.
References:
http://blog.renren.com/share/238213667/12127619538(strong recommended)
http://blog.renren.com/share/238213667/12149232211
As an engineering student, I have seldom read the books about psychology and don't know the transferring process of human knowledge. But now I learn the Stage Theory. The external stimulus needs to be processed initially into short-term memory, and finally into long-term memory through encoding. It causes my attention to the process of studying. No matter in childhood, high school or university, we are given a proper amount of homework/assignment besides attending class/lecture. The aim is to turn the short-term memory into long-term memory. Otherwise, we will forget about it soon and it is just a waste of time.
The 3 levels about cognition also impressed me. Actually, most of what I have thought about everyday news just stays in the first level. I just know it, and then go on knowing the next one. To make our mind further engaged, should we slow the steps to spend some time on thinking about that piece of news deeper? The answer is no in the past for me because in my mind it is useless. However, after research on the case about "KONY 2012", I understand that it is worthwhile to update our attitude to at least second level to every news, or the ones who don't know the truth are likely to be mislead under some evil purpose.
For example, hundreds of thousands of people online support US government to send military into Uganda in order to capture KONY. However, after deeper investigation and consideration, it is another invade aiming for petroleum in my opinion, just like Afghan's case.
Even not helpful, don't support the evil, only when we improve our cognition's level.
References:
http://blog.renren.com/share/238213667/12127619538(strong recommended)
http://blog.renren.com/share/238213667/12149232211
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