scholarly journals Power spectrum characterization of the Anderson transition

2006 ◽  
Vol 73 (2) ◽  
Author(s):  
Antonio M. García-García
Keyword(s):  
Power Spectrum ◽  
Anderson Transition

Statistical determination of geophysical well log response functions

Geophysics ◽  
1983 ◽  
Vol 48 (11) ◽  
pp. 1525-1535 ◽  
Author(s):  
Eugene A. Nosal
Keyword(s):  
Power Spectrum ◽  
Response Function ◽  
System Response ◽  
General Terms ◽  
Induction Logging ◽  
Conductivity Profile ◽  
Statistical Determination ◽  
The One

The vertical response function of induction logging tools is shown to be derivable from a power spectrum analysis of the measurement. The vertical response function is the one‐dimensional sequence of weights that characterizes how the tool combines the rock conductivities along the borehole to form an output called the apparent conductivity; it is the system impulse response. The value of knowing this function lies in the possible use of filter theory to aid in data processing and interpretation. Two general notions establish the framework for the analysis. The first is that logging is a linear, convolutional operation. Second, the earth’s conductivity profile forms a stochastic process. The probabilistic component is fleshed out by reasonably based assumptions about the occurrence of bed boundaries and nature of conductivity changes across them. Brought together, these tenets create a characterization of the conductivity sequence that is not a stationary process, but rather is intrinsic, as defined in the discipline of geostatistics. Such a process is described by a variogram, and it is increments of the process that are stationary. The connection between the power spectrum of the measurement and the system response function is made when the convolutional model is merged with the conductivity process. Some examples of induction log functions are shown using these ideas. The analysis is presented in general terms for possibly wider application.

A possible characterization of the homoeopathic effect

1997 ◽  
Vol 86 (01) ◽  
pp. 4-9 ◽  
Author(s):  
Guadalupe Ruiz Vega ◽  
José-Leonel Torres
Keyword(s):  
Power Spectrum ◽  
Peripheral Blood ◽  
Blood Circulation ◽  
The Body ◽  
Systematic Variation ◽  
Mathematical Treatment ◽  
Relevant Parameter ◽  
Electrical Signals ◽  
Peripheral Blood Circulation

AbstractElectrical signals from a photoelectric plethysmograph are used to test peripheral blood circulation as a source of a homoeopathically relevant parameter that will vary in a reproducible and systematic way following exhibition of specific medicines in homoeopathic doses. Mathematical treatment of the signals gives a Fourier power spectrum with an approximately linear profile (in a log-log plot) at the lowest frequencies. The gradient of this line seems to meet the above requirements of reproducible and systematic variation under a homoeopathic stimulus, and this is our basis to propose an analogous treatment for other electrical signals from the body, especially those from the heart and brain.

scholarly journals Low-Frequency Characterization of Music Sounds - Ultra-Bass Richness From the Sound Wave Beats

2021 ◽  
Author(s):  
Masahiro Morikawa
Keyword(s):  
Power Spectrum ◽  
Power Law ◽  
Sound Wave ◽  
Wave Amplitude ◽  
Low Frequency ◽  
Very Low Frequency ◽  
Resonance Characteristic ◽  
Solo Violin

Abstract The orchestra performance is full of sublime rich sounds. In particular, the unison of violins sounds different from the solo violin. We try to clarify this difference and similarity of unison and solo numerically analyzing the beat of ‘violins‘ with timbre, vibrato, melody, and resonance. Characteristic properties appear in the very low-frequency part in the power spectrum of the wave amplitude squared. This ultra-buss richness (UBR) can be a new characteristic of sound on top of the well-known pitch, loudness, and timbre, although being inaudible directly. We find this UBR is always characterized by a power-law at low-frequency with the index around −1 and appears everywhere in music and thus being universal. Furthermore, we explore this power-law property towards much smaller frequency regions and suggest possible relation to the 1/f noise often found in music and many other fields in nature.

The Use of Power Spectrum Density for Surface Characterization of Thin Films

2019 ◽  
pp. 379-411 ◽  
Author(s):  
Fredrick Madaraka Mwema ◽  
Esther Titilayo Akinlabi ◽  
Oluseyi Philip Oladijo ◽  
Oluseyi Philip Oladijo
Keyword(s):  
Thin Films ◽  
Power Spectrum ◽  
Surface Characterization ◽  
Power Spectrum Density ◽  
Spectrum Density

Measurement and Characterization of Surface Quality in Fast Tool Servo Machining of Optical Microstructures

2008 ◽  
Vol 381-382 ◽  
pp. 517-520 ◽  
Author(s):  
Chi Fai Cheung ◽  
Tsz Chun Kwok ◽  
Sandy To ◽  
Wing Bun Lee ◽  
Xiang Qian Jiang ◽  
...  
Keyword(s):  
Power Spectrum ◽  
Surface Quality ◽  
Surface Profile ◽  
Strong Relationship ◽  
Power Spectrum Analysis ◽  
Fast Tool Servo ◽  
Important Means ◽  
Micro Lens Array ◽  
Micro Lens

This paper presents a study of effect of cutting conditions on surface quality in FTS machining of optical microstructures such as micro-lens array. A power spectrum analysis is proposed to characterize the surface quality in FTS machining. It is found that there is a strong relationship between the surface roughness and the power spectrum of the surface profile. This provides an important means for the characterization of surface quality in FTS machining of optical microstructures.

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