School and Workshop on Structure and Function of Complex Networks: second day

In the following some comments about the Program of the second day.

Epidemics spreading
Indiana University, Bloomington, U.S.A.
Great Lecture! For now, Vespignani is my preferred lecturer. The lecture was very interesting and spoke about how to model deseases and their spreading and how you can immunitize nodes in order to stop the virus (immunize at random is not effective in general, immunizing the hub [nodes with a lot of connections] works very well [you immunize a tiny fraction of the nodes and the virus is stopped] but you have to have a global knowledge of the network that is often not the case. Taking node at random, asking to name a “connection” and immunize that connection works almost as well as immunizing the hubs but you don’t need global knowledge: in fact you are probably going to reach the hubs with this strategy.
He was speaking about sex networks, with the (to be expected) note that, when asked explicitly abou the number of sexual connections, men tend to overstimate and women tend to understimate. He said that there are already data on sexual networks from Sweden, US, UK, Zimbabwe, Uganda. Remind for myself: I need to have a look at them and download the data.
[Everyone here is speaking of Mean Field, but I have no idea what this is. Most of the people here are physicists. I had a check on the Mean Field Wikipedia page but I didn’t get it too much. I’ll have to ask someone, even if this is a bit like asking “what do you mean by 2+2 after 5 years of math”.]

Official visit – the Director General of UNESCO Mr. K. MATSUURA
I arrived late and it was boring.

Percolation on networks II
Bar-Ilan University, Ramat-Gan, Israel
Too mathematical for me. Certainly Havlin knows a lot about these things.

Models of scale free graphs
Very good speaker as well! The slides were perfect. There was some speaking about fractals, about fractals networks and pseudo-fractal graphs. He spoke about where there also some datasets to play with. He made some fun remarks at the end about the sexual networks but I can’t remember them. I need to get the slides that were perfect.

Search in random networks
HP Laboratories, Palo Alto, U.S.A.
I read most of her papers and it was great to see that there is a real person behind the name. Her lecture was interesting and not too hard to follow. Tomorrow she will speak about search on scale-free networks. I need to understand better what are these cutoffs in powerlaw distributions.

Network visualization
Indiana Unviersity, Bloomington, U.S.A.
In the next days we will have 3 computer sessions with her in which we will play with datasets and she also asked to bring our datasets. I think it will be fun. I read a paper by her some time ago about activeWorld and visualizations of footprints in a virtual library: very interesting! Anyway this talk was very different from the previoous talk, it was much more graphical, sometime phychological and surely not at all a formulas-dense one!
I will try to get the slides of this as well. Interesting picture of sociogram from a 1934 (!) paper by Moreno. Red and green has swapped meaning in China, compared to Italy.
I suggested her to look at the TrustArt wiki page I somehow maintain, there could be some interesting visualizations she had missed.

Game theory
Universidad de Alicante, Spain
He was great in condensing the all field in one hour and in doing it in a very intriguing way, basically only by examples. Very interesting and at the end he started explained how game theory relates to networks (formation). I took 6 pages of notes. The last line I wrote on my notes is “Economy is the science of greediness and egoism” (you know, all these assumptions about humans being rational, i.e. interested just in maximizing their instantaneous utility not caring for all the rest…)

4 thoughts on “School and Workshop on Structure and Function of Complex Networks: second day

  1. Stefano Mizzaro

    Enjoy the school!

    About the last sentences: “Economy is the science of greediness and egoism (you know, all these assumptions about humans being rational, i.e. interested just in maximizing their instantaneous utility not caring for all the rest…)”

    Try and read Dawkins’s “Selfish Gene” and Matt Ridley’s “The Origins of Virtue”…

    (I sent you an email about your visit to Udine, no hurry, when you have some info just let me know)


  2. Francesco

    Paolo, thanks for blogging about this school. I would be interested in the slides, too.

    Regarding network dataset for your experiments, I think many truly open, huge, meaningful dataset are now publicly available: Wikipedia, Flickr, delicious, Amazon/WebServ. They all are cooperatively created, heterogeneous, real world networked resources. You only need a bit of crawling to turn them into processable data. Of couse se xual networks data may prove more interesting… ;-)

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