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Article #259What is meant by the lack of a Characteristic scale?
From: Haripada Khatuya
Date: Thu, 17 Dec 1992 02:31
Date: Thu, 17 Dec 1992 02:31
41 lines
2590 bytes
2590 bytes
My question concerns the application of Multi-resolution stochastic processes in the area of signal processing. Most of the papers say this kind of analysis is useful for signals where there is no one single characteristic scale. o What exactly IS meant by a time series of signals having no characteristic scale? o Does the lack of a unique characteristic scale imply the non-existence of statistical moments? o Is there any body of statistical theory existent to detect the presence or absence of mutliple scales? o Is it true that multiplicity of scales imply signals with power-law (as opposed to exponential) correlation decay? I know that the issues of long-range range dependence (slow decay of correlations), 1/f noise, self-similarity, fractal supports, non-analytic distributions, power laws, wavelets, multi-resolution stochastic processes etc., are interlinked, but I haven't been able to find any rigorous (especially in terms of statistical theoretic models) links. For eg., Multi-fractal measures are now widely used in Physics, but I have yet to see them in any journal of statistics. There have been many journal articles on the application of Chaos theory to statistical analysis, but all of these concentrate on invariants like dimension and Lyapunov exponent estimates. I have seen NOT ONE article on the consequences on standard statistical tests and estimation procedures of substituting ,say, fractal spaces for the standard sample spaces of classical probability analyses. Also, can anybody expound on the link of the new theory of Self Organised Criticality to the presence of multiple scales,if any at all exist? Does the SOC model imply that the lack of a characteristic scale causes a breakdown of the traditional concept of "Causality", ie., a given input causes a definite response in output? This is beginning to sound wrong, but I'd still love to hear more on this. Any leads, clues, explanations, pointers, papers, references, etc. highly appreciated. Sorry about the long rather rambling post. Hari.
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Path: arc1-ca.pugleaf.net!sparky!uunet!spool.mu.edu!agate!netsys!news.cerf.net!network.ucsd.edu!sdcc12!sdcc3!hkhatuya From: hkhatuya@sdcc3.ucsd.edu (Haripada Khatuya ) Newsgroups: sci.fractals,sci.chaos,comp.theory.dynamic-sys Subject: What is meant by the lack of a Characteristic scale? Message-ID: <42665@sdcc12.ucsd.edu> Date: 17 Dec 92 02:31:28 GMT Sender: news@sdcc12.ucsd.edu Followup-To: sci.fractals Organization: University of California, San Diego Lines: 41 Nntp-Posting-Host: sdcc3.ucsd.edu