Hey, cool, our paper made in onto slashdot. Here are some vague answers to the many excellent questions.
First, our work deals with resilience of many kinds of networks, not just the Internet, and may be a better model of some of the others than it is of the Internet. As several people have pointed out, preserving connectivity in the Internet is kind of pointless if the performance is appalling, as it would be if you destroyed most of it. (We did actually make this point in an earlier version of the PRL paper, but it got cut out to make way for other things.)
The whole paper is available here, and if you look at it you'll see that we also talk about applications to things like the power grid, and contact networks which result in disease transmission. There are also many other important networks which one could apply it to. Distribution networks, like UPS or regular mail; transportation networks, like airline routes or highways; food webs; neural nets. One of the most interesting, perhaps, is not the Internet, but the Web, which is also a network (of pages linked together by links). This has also been shown to have a scale-free degree distribution (A. Broder et al., Computer Networks 33, 309 (2000)) and so should be highly robust in the sense that you can still surf from one place to another even if most of the pages in the Web disappeared overnight.
To answer the question about non-random failures, yes, things are very different there, and this is also discussed in the article. If you attack only the most highly connected domains/web sites/people/airline hubs, etc. you can destroy the operation of the network in no time at all. These networks are very vulnerable to directed attack. This could be very bad, but it some cases it is good. For instance, it means that a focused attack on a disease-causing contact network, for example through vaccination of the people with the highest number of contacts (the so-called "core group"), could prevent an epidemic with comparitively little effort. (Of course, identifying the core group may not be trivial.)
The guy who made the point about the Australian fiber dying last week is onto the right idea. This is the same effect - if you take out the right connection (or wrong, depending on your point of view), then you can do a lot of damage. It's only if you take out a random one that the network is robust.
This is actually a really good question. I had always assumed that, as in the Human Genome Project, it was not one human being sequenced, but parts of the genomes of many humans. At least according to CNN however, it *is* a particular human being in Celera's case. One particular human being, whose entire genome is going to be sequenced. (In fact, the CNN article says this is only the first of six people.) If this report is really true (it is CNN after all) then I would be very interested to know who it was. I'm sure a lot of politics went into the decision...
Slashdot Mirror
First, our work deals with resilience of many kinds of networks, not just the Internet, and may be a better model of some of the others than it is of the Internet. As several people have pointed out, preserving connectivity in the Internet is kind of pointless if the performance is appalling, as it would be if you destroyed most of it. (We did actually make this point in an earlier version of the PRL paper, but it got cut out to make way for other things.)
The whole paper is available here, and if you look at it you'll see that we also talk about applications to things like the power grid, and contact networks which result in disease transmission. There are also many other important networks which one could apply it to. Distribution networks, like UPS or regular mail; transportation networks, like airline routes or highways; food webs; neural nets. One of the most interesting, perhaps, is not the Internet, but the Web, which is also a network (of pages linked together by links). This has also been shown to have a scale-free degree distribution (A. Broder et al., Computer Networks 33, 309 (2000)) and so should be highly robust in the sense that you can still surf from one place to another even if most of the pages in the Web disappeared overnight.
To answer the question about non-random failures, yes, things are very different there, and this is also discussed in the article. If you attack only the most highly connected domains/web sites/people/airline hubs, etc. you can destroy the operation of the network in no time at all. These networks are very vulnerable to directed attack. This could be very bad, but it some cases it is good. For instance, it means that a focused attack on a disease-causing contact network, for example through vaccination of the people with the highest number of contacts (the so-called "core group"), could prevent an epidemic with comparitively little effort. (Of course, identifying the core group may not be trivial.)
The guy who made the point about the Australian fiber dying last week is onto the right idea. This is the same effect - if you take out the right connection (or wrong, depending on your point of view), then you can do a lot of damage. It's only if you take out a random one that the network is robust.
All the best,
Mark.
This is actually a really good question. I had always assumed that, as in the Human Genome Project, it was not one human being sequenced, but parts of the genomes of many humans. At least according to CNN however, it *is* a particular human being in Celera's case. One particular human being, whose entire genome is going to be sequenced. (In fact, the CNN article says this is only the first of six people.) If this report is really true (it is CNN after all) then I would be very interested to know who it was. I'm sure a lot of politics went into the decision...
I've met Hofstader. He's friendly and smart. Not pompous that I noticed.