Linked: The New Science of Networks 160
| Linked: The New Science of Networks | |
| author | Albert-László Barabási |
| pages | 229 |
| publisher | Perseus Publishing |
| rating | 10 |
| reviewer | kurtkilgor |
| ISBN | 0738206679 |
| summary | An introduction to scale-free networks and their broad applications |
It turns out that in the past few years, a decent amount of progress has been made on this front, largely thanks to the Internet. The Internet allows scientists to exchange information and speed up research, but more pertinently it is a test subject for these kinds of large-scale interaction problems. Linked: The New Science of Networks presents both the story of how the science has developed, and what it means. Unlike much popular scientific literature, the author himself is an active participant in the field.
The biggest surprise and most important lesson of the book is that the Internet, cellular biology, society, matter, and an incredible array of other seemingly unrelated things all form a particular type of structure called a scale-free network. These types of networks have only been described in detail recently, and their study promises to be as fundamental and rewarding as, for instance, waves or diffusion. The presence of the same structure in many unrelated situations suggests that there is a deep physical or mathematical principle which governs them.
The discovery of this principle is the subject of the first half of the book, which is a sort of detective story that leads from the most primitive concepts of graphs, as pioneered by Euler, to the state of the art. It is very interesting in itself to see how inconsistencies in mathematical models have led people to develop more and more accurate ideas of how such networks function. There is a tiny amount of math in the footnotes available for those who want it, but generally no prior knowledge is required. The author writes with plenty of anecdotes, especially in the beginning starting out with such introductions as this one of Paul Erdos:
"One afternoon in late 1920s Budapest, a seventeen-year-old youth cantered with a weird gait through the streets and stopped in front of an elegant shoe shop that sold custom-made shoes ... After knocking on the store's door-an act that would have seemed just as odd back then as today-he entered, ignoring the saleswoman at the counter, and went up to a fourteen-year-old boy in the back of the shop.'Give me a four digit number,' he said.
'2,532,' came the wide-eyed boy's reply . . .
'The square of it is 6,441,024,' he continued. 'Sorry, I am getting old and I cannot tell you the cube.'"
For another example of both the writing style and the unusual content, the author humorously describes the discovery of a similarity between Bose-Einstein condensation and economic monopoly:
"Essentially Microsoft takes it all. As a node, it is not just slightly bigger than its next competitor. In the number of its consumers it simply cannot be compared. We all behave like extremely social Bose particles, convenience condensing us into a faceless mass of Windows users. As we purchase new computers and install Windows, we carefully feed and maintain the condensate developed around Microsoft. The operation systems market carries the basic signatures of a network that has undergone Bose-Einstein condensation, displaying clear winner-takes-all behavior."
The rest of the book devotes a chapter to a particular example of a network: epidemics, the Internet, economics, etc. One thing is abundantly clear: the more we know about how these things work, the better we'll be able to curb DDOS attacks, stop disease, and control economic failures. An unlikely example of a scale-free network is the cell. It turns out that the interactions among a cell's proteins can be modeled this way, and if we could only understand it, we would be able to come up with treatments analytically, instead of by trial and error as it is done now.
It seems to me that with a greater understanding of networks, we will be able to finally advance in many fields in which progress is currently stalled. From firefly research to AIDS treatment, this is the Next Big Thing.
You can purchase Linked from bn.com. Slashdot welcomes readers' book reviews -- to see your own review here, read the book review guidelines, then visit the submission page.
Read in conjunction with ... (Score:3, Insightful)
The New Science (Score:4, Insightful)
The science of networks is not so new, but it is gaining importance rapidly. I'm interested in the application of network theory to the flow of information in structured populations. Network theory would be part of this, but so would other social theories (kinship, information, psychology, etc.)
for interesting papers on networks go to:
http://www.santafe.edu
the center for the science of complexity
Re:Read in conjunction with ... (Score:2, Insightful)
Please do not mix sociopolitics with physics (Score:2, Insightful)
Please stop drawing analogues between socioeconomical politics and physics.
Wasn't it enough that darwinism was used to promote fascism and ultraliberal capitalism and Einstein's relativity was used to promote moral relativism. All out of context, of course, but still bought by the people and - even worse - the politicians.
Read this book about six months ago.. (Score:2, Insightful)
Re:The New Science (Score:3, Insightful)
"... What is really interesting is that game theorists will borrow from network theorists, network theorists from game theorists, game theorists from evolutionary theorists, evolutionary theorists from game theorists, network theorists from evolutionary theorists, evolutionary theorists from AI theorists, and all of them from linguistics, philosophy, cognitive sciences, economics, and the other social sciences, computer modeling, agent-based modeling, etc. and visa versa..."
True, very true. Not only that, but the author of this book is a physicist!
95% of this book was familiar and/or easy to understand, coming from an AI and maths background. Where it occasionally lost me was in the sudden jumps and links between seemingly unrelated fields.
The Bose-Einstein condensation analogy with Microsoft's OS monopoly is one example of this. In the terms of the models Barabasi et al used, the discussion around this makes perfect sense*. It's only in the atmosphere of a physics department that such a connection would have been made, but the non-physicists reading the book could have done with a little more explanation. Most of the book, however, was extremely thorough and accessible.
*If I understand it correctly, the scale-free model predicts (and accounts for) the formation of hubs, but it is possible to modify the model such that the hubs can all converge to one level. This is governed by equations Einstein formulated in the 1920s. Nice to know, but not very clearly explained.
Re:In the Foundation series... (Score:3, Insightful)
You cannot use the knowledge of individuals to analyze society, just as you cannot use the knowledge of society to analyze individuals.
It's also -- forgive me for saying -- a little old-fashioned. It implies that there's a complete break between the individual and the society of which that individual is a part. One must have nothing to with the other. Given that every action by every individual has an impact in the society (however small) this seems unlikely. Like air in a room, the overall behaviour of the system will not be based on the behaviour of one gas molecule, but the system is still just an aggregation of gas molecules.
Might well be that it's of more practical value to study the two separately. Going from mass and electrical charge to "how to build a nice car" might be a long and twisty road. It's probably easier to model it with math that might be a little crass, but gets the job done. But it doesn't mean mass and charge have nothing to do with what the car is made of.
Excellent summary (Score:3, Insightful)
Re:Duhh.... (Score:3, Insightful)
For instance, in the game of chess, we understand _completely_ what each piece does, but that doesn't mean we can play a perfect game, or even a good game. Although it certainly is a prerequisite in this case.
And for instance, in a branch of physics known as critical phenomena, where one tries to explain the behavior of things like water evaporating, or magnets losing magnetization, etc. You can construct extremely simple models where there's like one lower level of abstraction to know, but then you can't answer extremely simple questions about higher levels of abstraction.
Let me draw an example, that is widely known as the Ising model of magnetism in physics. We can make a very very simple model of magnetism by saying that all magnetic spins can be UP or DOWN, and the energy is 1 if an adjacent pair of magnetic spins are the same, and -1 if the spins are different. Then we put all these little spins on a lattice, and we call this collection of little spins a _magnet_. Ok, this is a very very simple model, but now we ask, does this thing behave like a magnet? A tough question in 2 and 3 dimensions! Why? It's not because of errors in our assumptions, it's basically because we have very primitive mathematical tools to tackle this type of problem. We are forced to resort to mathematical tools such as infinite transfer matrices, and jordan-wigner transformations.
Yes, in one sense, I agree with your post, that round-off errors cause chaos to occur over very long simulations or models can be inaccurate and have bad predictions. But the spirit of the book is in examining very simple models that seem to have correct predictions, but are complicated enough that we can't manipulate these models with finesse to extract additional information about the system.
Re:In the Foundation series... (Score:3, Insightful)
If you were to read carefully, Hari makes the point that an individual does make no difference in the history of the Empire. The role that the indivudal plays in history can be predicted, but the individual to fill it (and when it's filled) doesn't really matter.
Even Hari was just filling a role. In Hari's case he was selectively bred for over a millenia by the Robots. His role was important but exactly why and what effect he would have, Daneel couldn't fathom. They bred him because long-term planning for humanity was just beyond the grasp of Robots.
Had Hitler never arrived, maybe Stalin would have gone rampaging through Europe. If Lincoln had not been president, another Unionist might have fallen into his place. If Lee Harvey Oswald had missed, maybe JFK would have died of drug overdoses. If Caesar hadn't been born, perhaps another with his ambition would have eventually become Dictator and Emperor. And so on.
Hari's larger point being that Stalin, Hitler, Lincoln, and Gandhi would all have been unimportant anyway. Even a figure whose impact was as dramatic as The Mule didn't really throw off the predictions of psychohistory by much. The Plan compensated even for him -- and he was completely unforseen.
100 or 200 years is a myopic view of history. Larger factors like nationalism, resource pressures, population expansion, steady trends in technology, industrialism, and so on drive history -- not individuals. Taking the longer view, psychohistory (acting in hindsight) may have predicted that near 100 BCE a large seafaring empire covering the entire Mediterranian, with effective military technology, efficient government structure, rigid social classes, and a strong military influence over government would have risen. It might not have been Roman, but should have happened anyway. It might have predicted factors which would cause the Empire to fall, and the feudalism which took hold shortly thereafter; inevitably the nation-states that arose out of the fuedalism would colonize to relief resource pressures; and so on...
"We know how people act individually..." (Score:2, Insightful)
Our lack of progress in sociology is a testament to our lack of understanding of the individual.