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1 Studies in the History of Statistics and Probability ... - Sheynin, Oscar

1 Studies in the History of Statistics and Probability ... - Sheynin, Oscar

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<strong>the</strong> structural function <strong>of</strong> <strong>the</strong> contents <strong>of</strong> <strong>the</strong> useful component is <strong>of</strong> <strong>the</strong>typeD(r) = αlnr + βwhere r is <strong>the</strong> distance between sample po<strong>in</strong>ts <strong>and</strong> α <strong>and</strong> β, parametersdeterm<strong>in</strong>ed by observation. However, <strong>the</strong> book has a number <strong>of</strong><strong>in</strong>consistencies. Thus, <strong>the</strong> logarithmic dependence is cont<strong>in</strong>ued <strong>in</strong>to <strong>the</strong><strong>in</strong>terval <strong>of</strong> small values <strong>of</strong> r which is impossible because D(r) is a nonnegativemagnitude. Then, <strong>in</strong> some cases <strong>the</strong> subject concerns <strong>the</strong>content, <strong>in</strong> o<strong>the</strong>r <strong>in</strong>stances, its logarithm. In addition, no statisticalchecks are made. But still, <strong>the</strong> factual material impresses so stronglythat careful reliable studies <strong>in</strong> <strong>the</strong> same direction become desirable.In radio physics, <strong>the</strong> scientific level is high <strong>and</strong> similar<strong>in</strong>consistencies just can not occur. However, as far as we know, noreports about successful apply<strong>in</strong>g <strong>the</strong> model <strong>of</strong> process with stationary<strong>in</strong>crements are <strong>in</strong> existence. Rytov (1966) only formulated ahypo<strong>the</strong>sis that <strong>the</strong> phenomenon <strong>of</strong> flicker should be thus described.In conclud<strong>in</strong>g, I deal <strong>in</strong> more detail with <strong>the</strong> statistical <strong>the</strong>ory <strong>of</strong>turbulence <strong>and</strong> <strong>the</strong> problem <strong>of</strong> forecast<strong>in</strong>g.3.6. Statistical <strong>the</strong>ory <strong>of</strong> turbulence. This <strong>the</strong>ory provides abrilliant success <strong>of</strong> a purely statistical description <strong>of</strong> a phenomenon, <strong>of</strong>a highly developed <strong>and</strong> very complicated turbulence with a largenumber <strong>of</strong> vortical movements on differ<strong>in</strong>g scales. Kolmogorov <strong>and</strong>Obukhov founded <strong>the</strong> basis <strong>of</strong> <strong>the</strong> <strong>the</strong>ory before 1941. Experimentalconfirmation <strong>of</strong> <strong>the</strong>ir <strong>the</strong>oretical conclusions dem<strong>and</strong>ed perfectmeasur<strong>in</strong>g <strong>in</strong>struments <strong>and</strong> up to 25 years. Application <strong>of</strong> that <strong>the</strong>oryto problems <strong>in</strong> propagation <strong>of</strong> electromagnetic <strong>and</strong> acousticoscillations <strong>in</strong> <strong>the</strong> atmosphere is also be<strong>in</strong>g developed.A precise knowledge <strong>of</strong> <strong>the</strong> field <strong>of</strong> velocities <strong>in</strong> a turbulent currentis underst<strong>and</strong>ably both impossible <strong>and</strong> useless. Indeed, had we somemethod <strong>of</strong> calculat<strong>in</strong>g all <strong>the</strong> velocities at all po<strong>in</strong>ts, <strong>the</strong>ir registrationwith sufficient precision would have alone dem<strong>and</strong>ed an unimag<strong>in</strong>ableamount <strong>of</strong> paper or magnetic tape <strong>and</strong> work with so much <strong>in</strong>formationis absolutely impossible. The situation should be resolved by someversion <strong>of</strong> a statistical description.It occurred that <strong>the</strong> ma<strong>in</strong> suitable notions can be borrowed from <strong>the</strong>correlation <strong>the</strong>ory; however, <strong>in</strong> <strong>the</strong>ir <strong>in</strong>itial form <strong>the</strong>y were <strong>in</strong>sufficient.There is a scientific law stat<strong>in</strong>g that ex nihilo nihil fit which means thatan application <strong>of</strong> established <strong>the</strong>ories does not cover anyth<strong>in</strong>g new.Without go<strong>in</strong>g <strong>in</strong>to ma<strong>the</strong>matical detail, I will attempt to showexactly how does this law work <strong>in</strong> case <strong>of</strong> turbulence <strong>and</strong> what newconsiderations it was necessary to draw for gett<strong>in</strong>g <strong>the</strong> th<strong>in</strong>gs mov<strong>in</strong>g.Imag<strong>in</strong>e a turbulent current. Its mean velocity depends on concreteconditions (what <strong>and</strong> where is <strong>the</strong> current set <strong>in</strong>to motion [...]) <strong>and</strong> it issenseless to describe it by statistical methods. However, <strong>the</strong>differences <strong>of</strong> velocity <strong>in</strong> various po<strong>in</strong>ts <strong>of</strong> <strong>the</strong> current <strong>and</strong> <strong>in</strong> differ<strong>in</strong>gmoments <strong>of</strong> time less depend on <strong>in</strong>itial conditions <strong>and</strong> to a largerextent are determ<strong>in</strong>ed by <strong>the</strong> properties <strong>of</strong> <strong>the</strong> liquid or gas itself. So,let us study <strong>the</strong> differences78

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