American science fiction writer Isaac Asimov (Isaac Asimov) Among his most famous sci-fi series "base" series (Foundation series) once in a science fiction over the future of social events can make a probabilistic forecast, called "psychological history" (psychohistory). The door of science fiction in the real world never realized before, and nobody knows whether it can be realized. However, a recent study the scientists, but it seems to have taken a small step in that direction.
[From a local law conflicts to "predict" the war]
December 2009, the University of Miami, USA (University of Miami) physicist Johnson (Neil Johnson) and his colleagues published a paper in the occurrence of various local conflicts around the world, including terrorist attacks, including law studied [Note 1]. Since "911", as local conflicts has been media attention. Johnson, who did his research in two things: one is nearly 55,000 times local conflicts statistical analysis found that there are some distinct laws in those conflicts seemingly random, the probability of such conflicts mostly inversely 2.5 power of deaths (slightly different with the specific powers of the region, but is usually between 2.3-2.8), and conflicts over the distribution of time there is a certain pattern. However, they are not the people who first discovered these phenomena. As early as half a century ago, British scientist Richard Johnson (Lewis Richardson) then conducted a similar study and found a similar phenomenon [Note 2]. But Johnson, who studies a part of his predecessors, and that is the second thing they do: explore the reasons behind these phenomena.
In geography and population density vary kingdom from vastly different cultural backgrounds who vastly different grounds waged conflict, why it will show almost the same law?
To answer this question, Johnson et al proposed a mathematical model. In the model, they are waging a conflict of various groups (mainly the guerrilla or terrorist organizations) behavior were analyzed. They assume their own development of those communities affected by two factors: one is to enhance the strength and merge with each other, the other is suffering due to the siege and the like fall apart. For those groups will launch attacks when Johnson, who believe that the media depends on the layout of the competition, in which the basic strategy is to avoid and other groups, "Zhuang Shan" in order to get as focused media attention. As for the number of deaths caused by the conflict, it was assumed to be proportional to the strength of the group. Using these assumptions, Johnson et al on a computer simulated war tens of thousands of results show that the statistical properties of the real data is very similar.
Encouraged by this result, Johnson et al claim that their model explains not only those laws in place in local conflicts, but also allows us to make probabilistic predictions about the time and scale of future conflict, In this sense, it does a bit like Asimov's fictional "psychological history." Moreover, Johnson, who also used their model suggests some methods to deal with local conflicts, such as those that interfere with communication groups, interventions media reports, security forces need to 15: 1 numerical superiority to suppress those organizations. They also cited the case of Afghanistan as a reminder of the last of: where a total of 25,000 Taliban militants, while the multinational forces and the Afghan security forces, including the number of people included in the forthcoming counter increased to 330,000 people, about 13: 1 advantage , very close to 15: 1. In addition, some are not obvious strategy, their model also provides a testing ground by a computer simulation to study its effectiveness.
These results caused widespread concern, with many media such as the "fog of war has been brushed aside," "War is predictable", "common law of all wars" as passionate language to describe Johnson et al study. Some popular science publications also Johnson et al's study is introduced. It also shares the enthusiasm spread to the military and police in some countries, such as the London police had attracted to Johnson terrorist risk consultancy 2012 London Olympics.
However, Johnson et al model really have the kind of media rendering abilities? Let's explore a little bit.
We first want to point out that Johnson and others suggested by many means, such as intervention or interference with communications media, in fact, is commonly used in military means, there are no unique. The security forces on the battlefield in Afghanistan and the Taliban armed 13: 1 personnel advantages, seemingly close to their recommendations, the actual meaning is rather vague, because the security forces of the Afghan forces and the Multinational Force combat power differences between the two the number of the simple sum is almost meaningless. Even the mathematical model they used, it is not a new thing, but a very close game theory (game theory) in a so-called "Eerfaluo bar problem" (El Farol Bar problem) the solution [Note C], which is they themselves noticed.
But even so, if Johnson et al model enables the collision probability associated with the number of deaths between we really appreciated it nonetheless is an important study.
Mathematics behind the natural beauty]
Well, Johnson et al model enables us to really understand the collision probability associated with the number of deaths between you? To explore this, let us expand the horizons a little number. Collision probability associated with the number of deaths between the Johnson et al found that in fact is not an isolated phenomenon, it has a name called a power law (power law), because it involves a mathematical power function on. In the wider world, there is a power law is extremely common, such as the distribution of noise in the engineering the social field stock fluctuations, city size, the number of scientific papers cited Wikipedia author biological and natural areas size associated with the kind of earthquake magnitude and frequency of the association, craters on the moon distribution, etc., are within a certain range, to a certain extent, to meet the power-law. Even Bach (Johann Sebastian Bach) Brandenburg Concerto (Brandenburg Concertos) spectrum, there are also power-law figure. The presence of a wide range of power-law, almost beyond random phenomena very common in a normal distribution (normal distribution) momentum, even by some researchers call a normal distribution than the normal distribution even.
In fact, Johnson, who also noted that they found in those local conflicts associated with exists, is also present in the financial field. In a sense, financiers or financial firms in the field of economic behavior and acts of guerrilla or terrorist organizations in planning terrorist attacks had some similarities: we are competing for limited resources, it is the former capital, after who - according to Johnson et al model - the media layout, and are included in the basic strategy by analyzing the behavior of other groups to avoid "Zhuangshan" this one, in order to seek the maximum, as well as unique profit [ Note D]. More similar, people in the financial sector has also made a lot of mathematical models, they also have a certain ability to fit the data, and some even have profitability (equivalent to prophecy). But cautionary, so far has not been considered to be a kind of financial model allows us to understand the real mechanism of the financial world.
Well, Johnson et al., The model will also do so?
Johnson thought the problem himself, but he thinks the answer is no, because their model is not a simple data fitting, but on the basis of social behavior guerrilla or terrorist organizations make reasonable assumptions above, thus greater credibility.
It should be said, the answer is not unreasonable. Explore some of the power-law from a social point of origin has indeed become many people's research, and even physical arXiv.org preprint archives also contain such research to explore, including the establishment of a category called Physics and Society (Physics early studies and Society), Johnson et al. had published there. However, examples of success in such studies rarely, there is a failure case is noteworthy. Half a century ago, the American linguist Zipf (George Zipf) distribution in the vocabulary of human language, and found a power law, that is, if the words are sorted by frequency of use, it is almost exactly to the number and frequency of use between inversely proportional to the power law is known as Zipf's law (Zipf's law). What is the origin of this power law is it? Zipf studied his research is also from a social point of view to start. But later it was found that Zipf's Law is not really unique to human language. In fact, if the monkeys a typewriter, not beat it with a keyboard spacebar, and assumes the same key for each letter was knocked to the probability that the monkey and win the "Glossary" will meet Zipf's law. Therefore, Zipf's Law is not so much the existence of social origin, as it is more likely just a random phenomenon in a simple mathematical laws, like everywhere in random phenomena as the normal distribution, Zipf from a social point of start Study plausible, in fact, it is misguided.
Although we can not consider Johnson's research is true, but the law has the extraordinary power of universality, in itself means that many models are likely to lead to a power law, which can not rely on the results of a model to fit easily It concluded that the effectiveness of the model itself, and this is the way we look at this kind of research should be some caution.
Before concluding this article, let's talk about a few power-law. So far, the origin of the power law is still a mystery, but there is an essential feature of long attracted people's attention in the power law, that is, the so-called scale invariance, which describes the data used in the unit no matter how change (such as the length of the unit whether it is in millimeters, meters or kilometers), the power-law are not affected (ie power of unchanged). So what kind of system the presence of scale invariance it? There are two types: one is the internal dimension of the system does not exist, the other is there are many different inherent scale systems, the former usually meet stringent power law, which is typically satisfied approximate power law. The presence of power-law was so widespread, largely because of the latter. The famous fractal theory expert Mandela Brott (Beno? T Mandelbrot) once said, a mountain in order to fun, you must have on many different scales landscapes (peaks, valleys, cliffs, cracks, etc.). This is an important part of the natural beauty, the soil is the power law arise.
Johnson et al., Whether it is effective and perhaps to be further assessed, but there are many issues worth exploring behind the power-law model in the world is no doubt.
Comment:
1, much of this work as early as 2005-2006 years to complete, but not published in well-known publications, and in 2009 due to the work published in "Nature" (Nature) magazine, causing widespread concern.
2, Richard Johnson is the study of regular warfare, get a power of 1.5, unlike Johnson, et al. The results, which indicate the presence of systematic differences formal war and local conflicts. In this paper, the so-called "prediction" just war followed media terms, is actually "predict" local conflicts.
3, the problem is the game Eerfaluo bar questions about a group of people to choose whether to go to the bar, select the basic strategy is to avoid visiting crowded at the bar too, with this model, Johnson et al., Guerrilla or terrorist organizations avoid the media forum It has been very similar to the attack when full.
4, the comparison is a bit unfair to the financiers, but it is not the original article, Johnson et al., And many media have done such a comparison.
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