There's other edges that if we take them out, things are still connected.

What is homophily?

Dance has never had a better friend than technology.

Laughs

It's very exciting work.

Off camera. Male voice

So there's a fair amount of interconnection between a node's neighbors.

That's all I'd like to say about shortest paths and weighted graphs in this unit.

Well, I use Facebook and Twitter.

So, lets imagine there is some problem called graph partitioning which is a real problem.

This example illustrates two things that are central to this course.

For a more efficient way, take CS215! See ya there. Excuse me!

This has been fairly well studied.

What it's telling us is that capitalism is going to become more social.

That our ideas reach other people who think as we do.

Let's go out on the street and ask people about social networks.

Yes.

A community of people with the same interests.

Off camera. Male voice

What attracted me the most was Facebook.

There's these issues that are taking place.

But I didn't appear in that comic book with him, so that's not a very good metric.

The first is the idea of a social network.

Michael So that's not a connection we can make.

That strips all the physical mass out of information, so now it's almost zero cost to copy and share information.

Unit four explores the notion of statistics, numbers that summarize complex structures like social networks.

Duncan Watts is one of the world experts in analyzing social networks and learning about what's going on inside of that.

I did not go and measured these animals' brains.

Hi! I'm Michael Lipman. I'm going to be teaching CS215 for Udacity.

We weren't able to get video footage of our conversation together but I think you'll find it interesting anyway.

We spend an evening on the social network instead of going to the pub with friends.

Barack Obama won (Applause) because he mobilized people as never before through the use of social networks.

Is it the political movement that suggests that people should be allowed to marry people of the same sex?

He has interned at a number of different companies, and this summer he interned with a company called Meebo that does some social networking.

It's just, how do we make that recurrent and scale it?

So, the nice thing about these structures is they do kind of have an essence of looking like real social network graphs.

So, this is how it comes in cybersecurity, and in fact if you think about it social networks are built on top of information networks and that's built on top of physical networks, and so the interdependency between these networks is very interesting to study and see, well, if I take out part of a physical network how will that affect the information network and the social network.

Or for example in more common day we say Birds of a feather flock together.

And it creates this kind of social network around a collection of digital photographs that you've actually taken.

We're going to be looking at Big Theta in the context of understanding the relationship of individuals in a social network and the connections between them.

You have a situation where the relationship between government and local social networking companies is creating a situation where, effectively, the empowering potential of these platforms is being constrained because of these relationships between companies and government.

No. . . well, yes. Now I know two!

Up to this point in the unit, we've been talking about very, very structured graphs, very clean and organized graphs things like chains or rings or grids, hypercubes that have a great deal of structure, and they look very different from the kids of actual social network graphs that you see in the wild.

No it doesn't change the time, big O or the clustering coefficient in the social network.

No it doesn't change the time, big O or the clustering coefficient in the social network.