web science-2019讨论区

Group 17: discussion about session 2

 
邢鹏举的头像
Group 17: discussion about session 2
邢鹏举 发表于 2019年05月21日 Tuesday 15:37
 

The network is the foundation and important component of the World Wide Web.There are many networks around us, such as:transport networks, power networks.

ChenYijie的头像
Re: Group 17: discussion about session 2
ChenYijie 发表于 2019年05月22日 Wednesday 08:58
 

Yes, we are still in a large social network, and even say that the network is closely related to us everywhere.There are many kinds of networks, and the relationship between them is very complex, but it can be roughly divided into uniform structure and chaotic structure.

梅祖昊的头像
回复: Group 17: discussion about session 2
梅祖昊 发表于 2019年05月22日 Wednesday 09:09
 

We can also analyze it in terms of nodes. For example, nodes can represent train stations, power stations,people.The edges between nodes represent their relationships.

丁修权的头像
回复: Group 17: discussion about session 2
丁修权 发表于 2019年05月22日 Wednesday 10:21
 

That's right, and many networks conform to the theory called six degrees of separation.

路宇轩的头像
回复: Group 17: discussion about session 2
路宇轩 发表于 2019年05月22日 Wednesday 10:33
 

So why the number is six, not five or seven, can it be solved out by a mathematical way?

曹昂的头像
回复: Group 17: discussion about session 2
曹昂 发表于 2019年05月22日 Wednesday 16:51
 

I heard it's because an experiment. In the 1960s, Milgren, a social psychologist at Yale University, designed a chain letter experiment. He randomly sent a chain letter to 160 people living in Omaha, Nebraska, in which he placed the name of a Boston stockbroker and asked each recipient to send the letter to a friend who he thought was closer to the stockbroker. A friend will do the same when he receives the letter. Eventually, most of the letters arrived at the stockbroker after five or six steps.The concept of six-degree partition (also known as "six-degree space") comes from this. And many scientists have studied this theory and proved it to some extent.

XiaoZixuan的头像
Re: 回复: Group 17: discussion about session 2
XiaoZixuan 发表于 2019年05月22日 Wednesday 18:26
 

You have raised a very interesting question. Actually, the number is not 6, is 5.2. This is a social experiment done by Milgram (he was also famous for his Electric shock experiment), in his study, he asked some subjects to make a contact with a target person (most of the subjects have no direct connection with the target person), only through letters. Subjects first mailed to their acquaintances, then acquaintances mailed to their acquaintances...finally make a connection between target person. The results that the mean number of intermediaries between starters and targets is 5.2, and in follow experiments the mean number is between 4-7. So the reason way this theory is a "Six" Degrees of Separation theory was not due to six its own specialty, but because six is a representation of several special numbers.

Let me make some extensions. This social finding became a mathematical network model in 1998, this was a very famous model, which open a new stage to the complex network researches, it is called ‘small-world’ networks. If you are interesting, you can read that paper published on Science at 1998, see attachment. Milgram's paper is also attached.

路宇轩的头像
回复: Group 17: discussion about session 2
路宇轩 发表于 2019年05月22日 Wednesday 10:38
 

Well, for the World Wide Web, the link between web pages are not a normal distribution. A great majority of pages have very few links. It is in line with my life experiences.

曹昂的头像
回复: Group 17: discussion about session 2
曹昂 发表于 2019年05月22日 Wednesday 16:44
 

Yes,it is dominated by small number of powerful hubs.it is a principal known as preferential attachment.

XiaoZixuan的头像
Re: 回复: Group 17: discussion about session 2
XiaoZixuan 发表于 2019年05月22日 Wednesday 17:50
 

Network analysis are very powerful. They are a very powerful tool for web Science and modeling and modeling and understanding how things are connected.

ChenYijie的头像
Re: 回复: Group 17: discussion about session 2
ChenYijie 发表于 2019年05月22日 Wednesday 18:29
 

But we must remember that networks are just an abstraction even if they are very useful one.

XiaoZixuan的头像
Re: Group 17: discussion about session 2
XiaoZixuan 发表于 2019年05月22日 Wednesday 18:34
 

I think it's an interesting topic who is the most powerful person in the network.

曹昂的头像
回复: Re: Group 17: discussion about session 2
曹昂 发表于 2019年05月22日 Wednesday 19:39
 

Yes, and we can think about it in different ways.The simplest analysis is to simply count up the connections for each node.We can claim that the node with the highest degree is the on that is best positioned in the network.