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M. V. Simkin

Publications and source records attributed to M. V. Simkin.

At least 37 records · Page 2Linked to original sources
arXiv2011

Estimating achievement from fame

We report a method for estimating people's achievement based on their fame. Earlier we discovered (cond-mat/0310049) that fame of fighter pilot aces (measured as number of Google hits) grows exponentially with their achievement (number of victories). We hypothesize that the same functional relation between achievement and fame holds for other professions. This allows us to estimate achievement for professions where an unquestionable and universally accepted measure of achievement does not exist. We apply the method to Nobel Prize winners in Physics. For example, we obtain that Paul Dirac, who is hundred times less famous than Einstein contributed to physics only two times less. We compare our results with Landau's ranking.

physics.soc-ph↗
arXiv2011

Re-inventing Willis

Scientists often re-invent things that were long known. Here we review these activities as related to the mechanism of producing power law distributions, originally proposed in 1922 by Yule to explain experimental data on the sizes of biological genera, collected by Willis. We also review the history of re-invention of closely related branching processes, random graphs and coagulation models.

physics.soc-ph↗
arXiv2010

An explanation of the distribution of inter-seizure intervals

Recently Osorio et al (Eur. J. Neurosci., 30 (2009) 1554) reported that probability distribution of intervals between successive epileptic seizures follows a power law with exponent 1.5. We theoretically explain this finding by modeling epileptic activity as a branching process, which we in turn approximate by a random walk. We confirm the theoretical conclusion by numerical simulation.

q-bio.NC↗
arXiv2008

Theory of aces: high score by skill or luck?

We studied the distribution of World War I fighter pilots by the number of victories they were credited with, along with casualty reports. Using the maximum entropy method we obtained the underlying distribution of pilots by their skill. We find that the variance of this skill distribution is not very large, and that the top aces achieved their victory scores mostly by luck. For example, the ace of aces, Manfred von Richthofen, most likely had a skill in the top quarter of the active WWI German fighter pilots and was no more special than that. When combined with our recent study (cond-mat/0310049), showing that fame grows exponentially with victory scores, these results (derived from real data) show that both outstanding achievement records and resulting fame are mostly due to chance.

physics.soc-ph↗
arXiv2008

A theory of web traffic

We analyze access statistics of several popular webpages for a period of several years. The graphs of daily downloads are highly non-homogeneous with long periods of low activity interrupted by bursts of heavy traffic. These bursts are due to avalanches of blog entries, referring to the page. We quantitatively explain this behavior using the theory of branching processes. We extrapolate these findings to construct a model of the entire web. According to the model, the competition between webpages for viewers pushes the web into a self-organized critical state. In this regime, the most interesting webpages are in a near-critical state, with a power law distribution of traffic intensity.

physics.soc-ph↗
arXiv2007

A mathematical theory of citing

Recently we proposed a model in which when a scientist writes a manuscript, he picks up several random papers, cites them and also copies a fraction of their references (cond-mat/0305150). The model was stimulated by our discovery that a majority of scientific citations are copied from the lists of references used in other papers (cond-mat/0212043). It accounted quantitatively for several properties of empirically observed distribution of citations. However, important features, such as power-law distribution of citations to papers published during the same year and the fact that the average rate of citing decreases with aging of a paper, were not accounted for by that model. Here we propose a modified model: when a scientist writes a manuscript, he picks up several random recent papers, cites them and also copies some of their references. The difference with the original model is the word recent. We solve the model using methods of the theory of branching processes, and find that it can explain the aforementioned features of citation distribution, which our original model couldn't account for. The model can also explain "sleeping beauties in science", i.e., papers that are little cited for a decade or so, and later "awake" and get a lot of citations. Although much can be understood from purely random models, we find that to obtain a good quantitative agreement with empirical citation data one must introduce Darwinian fitness parameter for the papers.

physics.soc-ph↗
arXiv2007

A scientific inquiry into modern art

I report the results of the test, where the takers had to tell true masterpieces of abstract art from the fakes, produced by me. I describe each picture by the fraction of the test takers, who selected it as a masterpiece. When I compare the pictures using this metric, they show no stratification between masterpieces and fakes. This suggests that they are of about the same quality.

physics.soc-ph↗
arXiv2007

An introduction to the theory of citing

Statistical analysis of repeat misprints in scientific citations leads to the conclusion that about 80% of scientific citations are copied from the lists of references used in othe papers. Based on this finding a mathematical theory of citing is constructed. It leads to the conclusion that a large number of citations does not have to be a result of paper's extraordinary qualities, but can be explained by the ordinary law of chances.

math.ST↗
arXiv2005

Theory of Aces: Fame by chance or merit?

We study empirically how fame of WWI fighter-pilot aces, measured in numbers of web pages mentioning them, is related to their achievement or merit, measured in numbers of opponent aircraft destroyed. We find that on the average fame grows exponentially with achievement; to be precise, there is a strong correlation (~0.7) between achievement and the logarithm of fame. At the same time, the number of individuals achieving a particular level of merit decreases exponentially with the magnitude of the level, leading to a power-law distribution of fame. A stochastic model that can explain the exponential growth of fame with merit is also proposed.

cond-mat.dis-nn↗
arXiv2004

Stochastic modeling of citation slips

We present empirical data on frequency and pattern of misprints in citations to twelve high-profile papers. We find that the distribution of misprints, ranked by frequency of their repetition, follows Zipf's law. We propose a stochastic model of citation process, which explains these findings, and leads to the conclusion that 70-90% of scientific citations are copied from the lists of references used in other papers.

cond-mat.dis-nn↗
arXiv2003

Copied citations create renowned papers?

Recently we discovered (cond-mat/0212043) that the majority of scientific citations are copied from the lists of references used in other papers. Here we show that a model, in which a scientist picks three random papers, cites them,and also copies a quarter of their references accounts quantitatively for empirically observed citation distribution. Simple mathematical probability, not genius, can explain why some papers are cited a lot more than the other.

cond-mat.dis-nn↗
arXiv2002

Read before you cite!

We report a method of estimating what percentage of people who cited a paper had actually read it. The method is based on a stochastic modeling of the citation process that explains empirical studies of misprint distributions in citations (which we show follows a Zipf law). Our estimate is only about 20% of citers read the original.

cond-mat.dis-nn↗
arXiv2002

What is the true dropped calls rate when in the test it was found to be zero?

We study the distributions of dropped calls rates for different wireless (cellular) carriers in different markets. Our statistics comprises over 700 different market/carrier combinations. We find that the dropped calls rates distribution is very close to lognormal. We derive an equation for the most probable dropped calls rate for particular carrier in particular market, which depends on the number of dropped calls observed, total number of calls and the parameters of the lognormal distribution. We apply this analysis to blocked and "no service" calls as well.

physics.data-an↗
arXiv2000

Umklapp Scattering and Heat Conductivity of Superlattices

The mean free path of phonons in superlattices is estimated. It is shown to be strongly dependent on the superlattice period due to the Umklapp scattering in subbands. It first falls with increasing the superlattice period until it becomes comparable with the latter after what it rises back to the bulk value. Similar behavior is expected of heat conductivity, which is proportional to the mean free path.

cond-mat.mtrl-sci↗
arXiv1999

Minimum Thermal Conductivity of Superlattices

The phonon thermal conductivity of a multilayer is calculated for transport perpendicular to the layers. There is a cross over between particle transport for thick layers to wave transport for thin layers. The calculations shows that the conductivity has a minimum value for a layer thickness somewhat smaller then the mean free path of the phonons.

cond-mat.mtrl-sci↗
arXiv1998

Magnetic Properties of a Bose-Einstein Condensate

Three hyperfine states of Bose-condensed sodium atoms, recently optically trapped, can be described as a spin-1 Bose gas. We study the behaviour of this system in a magnetic field, and construct the phase diagram, where the temperature of the Bose condensation $T_{BEC}$ increases with magnetic field. In particular the system is ferromagnetic below $T_{BEC}$ and the magnetization is proportional to the condensate fraction in a vanishing magnetic field. Second derivatives of the magnetisation with regard to temperature or magnetic field are discontinuous along the phase boundary.

cond-mat.stat-mech↗