共查询到20条相似文献,搜索用时 15 毫秒
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Comparison of detrending methods for fluctuation analysis 总被引:2,自引:0,他引:2
We examine several recently suggested methods for the detection of long-range correlations in data series based on similar ideas as the well-established Detrended Fluctuation Analysis (DFA). In particular, we present a detailed comparison between the regular DFA and two recently suggested methods: the Centered Moving Average (CMA) Method and a Modified Detrended Fluctuation Analysis (MDFA). We find that CMA performs the same as DFA in long data with weak trends and is slightly superior to DFA in short data with weak trends. When comparing standard DFA to MDFA we observe that DFA performs slightly better in almost all examples we studied. We also discuss how several types of trends affect different types of DFA. For weak trends in the data, the new methods are comparable with DFA in these respects. However, if the functional form of the trend in data is not a-priori known, DFA remains the method of choice. Only a comparison of DFA results, using different detrending polynomials, yields full recognition of the trends. A comparison with independent methods is recommended for proving long-range correlations. 相似文献
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J. T. Mitchell 《The European Physical Journal A - Hadrons and Nuclei》2007,31(4):851-853
The PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC) has made measurements of event-by-event fluctuations in
the charged-particle multiplicity as a function of collision energy, centrality, collision species, and transverse momentum
in several heavy-ion collision systems. It is observed that the fluctuations in terms of σ
2/μ
2 exhibit a universal power law scaling as a function of Nparticipants that is independent of the transverse momentum range of the measurement. 相似文献
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A method of evaluating human visual impressions of gray scale textures using morphological manipulation is proposed. To study
the effects of textural features on human Kansei, we introduced a texture analysis method based on mathematical morphology. Kansei is a Japanese word for sensibility or emotion. Kansei engineering is an approach to connect human sensibility with engineering applications. The proposed method allows us to manipulate
global and local properties of a texture separately. Variations of textures were generated by repetitively modifying arranged
objects and configurations of the arrangements of original textures. The manipulated textures were presented to human respondents
and the similarity of those textures based on human impressions was evaluated. Hierarchical clustering was applied to the
similarity matrix generated from respondents’ observations. The results of the human evaluation were compared with that of
the objective similarity evaluation adopting six global textural features. The global features such as density, regularity,
and directionality of the point configurations were shown to have significant effects on human visual impressions and identification
of textures. In the case of a texture without significant characteristics in its point configuration, local features such
as grain shape have an effect on visual impressions. 相似文献
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M. Suzuki 《Physics letters. A》1976,56(2):71-72
The idea of generalized scale transformation of time is introduced to evaluate asymptotically the relaxation and fluctuation in non-equilibrium systems. This scaling theory is demonstrated to be very powerful in discussing the relaxation just from the instability point. 相似文献
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《Nuclear Physics B》1986,275(4):617-640
Results of Monte Carlo simulations of a model of random surfaces based on planar random triangulations with gaussian embedding in D-dimensional euclidean space are presented, for various positive and negative values of D and various forms for the action. Estimates are given for the fractal dimension (Hausdorff dimension of the embedding) and the spreading dimension (intrinsic Hausdorff dimension). The scaling properties appear to depend on the short-distance properties of the triangulations and seem to be nonuniversal, at least for positive D. 相似文献
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Masuo Suzuki 《Physica A》1977,86(3):622-628
The general scaling theory of transient phenomena near the instability point, which has been proposed by the author, is applied to investigate the fluctuation and relaxation of superradiance from the complete inversion. This study gives a foundation or justification of the treatment of Glauber and Haake. 相似文献
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Gilles Besnard Sandra Guérard Stéphane Roux François Hild 《Optics and Lasers in Engineering》2011,49(1):71-81
A new method is proposed to estimate arbitrary velocity fields from a time series of images acquired by a single camera. This approach, here focused on a single spatial plus a time dimension, is specialized to the decomposition of the velocity field over rectangular shaped (finite-element) bilinear shape functions. It is therefore assumed that the velocity field is essentially aligned along one direction. The use of a time sequence over which the velocity is assumed to have a smooth temporal change allows one to use elements whose spatial extension is much smaller than in traditional digital image correlation based on successive image pairs. This method is first qualified by using synthetic numerical test cases, and then applied to a dynamic tensile test performed on a tantalum specimen. Improvements with respect to classical digital image correlation techniques are observed in terms of spatial resolution. 相似文献
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Paul Mandel 《Optics Communications》1985,55(4):293-296
We investigate analytically the switching process of a bistable system which is described near each limit point by a single ordinary nonlinear differential equation. For a holding beam near the limit point and a rectangular switching pulse, we prove that the requirement of switching imposes a constraint on the pulse area. This results hold for bistability in general and is applied to purely dispersive optical bistability. 相似文献
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Global optimization (GO) is one of the key numerical tools in computational physics. Among the GO algorithms the ones originating in statistical physics are particularly powerful. Recently an adaptive scheme was developed to increase the efficiency of one of these algorithms (stochastic tunneling). This scheme is based on the time-series of minima tested and the respective detrended fluctuation analysis (DFA). We here present a study on another GO methodology (energy landscape paving), which in itself is adaptive, and show that its performance is optimal under the DFA analysis. We give arguments to explain this fact. 相似文献
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Hadizadeh MR Yamashita MT Tomio L Delfino A Frederico T 《Physical review letters》2011,107(13):135304
We evidence the existence of a universal correlation between the binding energies of successive four-boson bound states (tetramers), for large two-body scattering lengths (a), related to an additional scale not constrained by three-body Efimov physics. Relevant to ultracold atom experiments, the atom-trimer relaxation peaks for |a|→∞ when the ratio between the tetramer and trimer energies is ?4.6 and a new tetramer is formed. The new scale is also revealed for a < 0 by the prediction of a correlation between the positions of two successive peaks in the four-atom recombination process. 相似文献
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We present a universal scaling law for all geometrically parallelized computer simulation algorithms. For algorithms with local interaction laws we calculate the scaling exponents for zero and infinite lattice size. The scaling is tested on local (cellular automata, Metropolis Ising) as well as cluster (Swendsen-Wang) algorithms. The practical aspects of the scaling properties lead to a simple recipe for finding the optimum number of processors to be used for the parallel simulation of a particular system. 相似文献