scholarly journals The contribution of Fourier amplitude spectrum differences to the early electrophysiological (i.e. P1) amplitude difference between face and nonface object categories

2010 ◽  
Vol 10 (7) ◽  
pp. 662-662
Author(s):  
C. Jacques ◽  
B. Rossion
Keyword(s):  
Amplitude Spectrum ◽  
Fourier Amplitude ◽  
Amplitude Difference ◽  
Object Categories ◽  
Fourier Amplitude Spectrum

scholarly journals The Influence of Typography on Algorithms That Predict the Speed and Comfort of Reading

2020 ◽  
Author(s):  
Arnold Wilkins ◽  
Katie Smith ◽  
Olivier Penacchio
Keyword(s):  
Amplitude Spectrum ◽  
Visual Comfort ◽  
Fourier Amplitude ◽  
Font Design ◽  
Spatial Regularity ◽  
Line Separation ◽  
Fourier Amplitude Spectrum

The speed with which text can be read is determined in part by the spatial regularity and similarity of vertical letter strokes as assessed by the height of the first peak in the horizontal autocorrelation of the text. The height of this peak was determined for two passages in 20 fonts. The peak was unaffected by the size of the text or its content but was influenced by the font design. Sans serif fonts usually had a lower peak than serif fonts because the presence of serifs resulted in a more even spacing of letter strokes. There were small effects of justification and font- dependent effects of font expansion and compression. The visual comfort of images can be estimated from the extent to which the Fourier amplitude spectrum conforms to 1/f. Students were asked to adjust iBooks to obtain their preferred settings of font and layout. The preference was predicted by the extent to which the Fourier amplitude spectrum approximated 1/f, which in turn was jointly affected by the design of the font, its weight and the ratio of x-height to line separation. The above algorithms can be usefully applied to any orthography to estimate likely speed and comfort of reading.

Site response analysis of liquefiable soil employing continuous wavelet transform

2022 ◽  
Vol 12 (1) ◽  
pp. 1-33
Author(s):  
D. Chavan ◽  
T.G. Sitharam ◽  
P. Anbazhagan
Keyword(s):  
Wavelet Transform ◽  
Site Response ◽  
Amplitude Spectrum ◽  
Ground Surface ◽  
Time History ◽  
Response Analysis ◽  
Fourier Amplitude ◽  
Acceleration Time ◽  
Liquefiable Soil ◽  
Fourier Amplitude Spectrum

Propagation of the earthquake motion towards the ground surface alters both the acceleration and frequency content of the motion. Acceleration time record and Fourier amplitude spectrum of the motion reveal changes in the acceleration and frequency content. However, Fourier amplitude spectrum fails to give frequency-time variation. Wavelet transform overcomes this difficulty. In the present study, site response analysis of a liquefiable soil domain has been investigated employing wavelet transform. Three earthquake motions with distinct predominant frequencies are considered. It is revealed that the moment soil undergoes initial liquefaction, it causes a spike in the acceleration time history. Frequency of the spikes is found to be greater than the predominant frequency of the acceleration-time history recorded at the ground surface from the analysis. Interestingly, the spikes belong to the sharp tips of the shear stress-shear strain curve. Immediately after the spike, acceleration deamplification is observed. Post-liquefaction deamplification (filtering) of the frequency components is also observed.

scholarly journals Seismic Response of Anchor + Hinged Block Ecological Slope by Shaking Table Tests

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Hui Su ◽  
Yijun Hang ◽  
Yongsheng Song ◽  
Kunming Mao ◽  
Dongyue Wu ◽  
...  
Keyword(s):  
Natural Frequency ◽  
Amplitude Spectrum ◽  
Shaking Table ◽  
Engineering Practice ◽  
Shaking Table Tests ◽  
Fourier Amplitude ◽  
Earthquake Excitation ◽  
Ecological Requirements ◽  
Acceleration Amplification ◽  
Fourier Amplitude Spectrum

Landslides caused by earthquakes and other natural disasters may cause serious economic and personal losses. Slope protections are usually applied in engineering practice to prevent significant slope slides and damages. Based on the mechanical and ecological requirements on slope protections, this paper put forward a new type of anchor + hinged block ecological slope and carried out shaking table tests on it and other three traditional slope protections for comparing. By shaking table tests, the acceleration amplification factors and Fourier amplitude spectrums of four different slope types are analyzed and compared to verify the suitability of this new slope protection under earthquakes. The results indicated that the natural frequency and the acceleration Fourier amplitude spectrum of the four tested slope protections change according to internal materials. The anchor + hinged block ecological slope has higher natural frequency comparing to traditional slopes, so the resonance cycle from earthquake excitation can effectively be avoided and as a result the anchor + hinged block ecological slope can achieve better seismic performance.

On: “Statistical Models for Interpreting Aeromagnetic Data” by A. Spector and F. S. Grant (GEOPHYSICS, v. 35, p. 293–302)

Geophysics ◽  
1971 ◽  
Vol 36 (3) ◽  
pp. 617-617
Author(s):  
Gudmundur Gudmundsson
Keyword(s):  
Power Spectrum ◽  
Statistical Models ◽  
Amplitude Spectrum ◽  
Magnetic Anomalies ◽  
Aeromagnetic Data ◽  
Fourier Amplitude ◽  
Rectangular Block ◽  
Single Block ◽  
Fourier Amplitude Spectrum

In their paper “Statistical Models for Interpreting Aeromagnetic Data,” Spector and Grant define the “power spectrum” of the magnetic anomalies over a single rectangular block as the squared Fourier amplitude spectrum. For their expression of the “power spectrum” of a single block, Spector and Grant quote Bhattacharyya (GEOPHYSICS, v. 31, p. 97–121).

scholarly journals Feature Extraction Method for Hydraulic Pump Fault Signal Based on Improved Empirical Wavelet Transform

Processes ◽  
2019 ◽  
Vol 7 (11) ◽  
pp. 824 ◽  
Author(s):  
Zheng ◽  
Wang ◽  
Zhu ◽  
Tang ◽  
Wang
Keyword(s):  
Wavelet Transform ◽  
Power Spectrum ◽  
Amplitude Spectrum ◽  
Hydraulic Pump ◽  
Fourier Amplitude ◽  
Feature Extraction Method ◽  
Empirical Wavelet Transform ◽  
Novel Method ◽  
Feature Information ◽  
Fourier Amplitude Spectrum

There are many interference components in Fourier amplitude spectrum of a contaminated fault signal, and thus the segment obtained based on the spectrum can lead to serious over-decomposition of empirical wavelet transform (EWT). Aiming to resolve the above problems, a novel method named improved empirical wavelet transform (IEWT) is proposed. Because the power spectrum is less sensitive to the contaminated interference and manifests the presence of fault feature information, IEWT replaces the Fourier amplitude spectrum of EWT with power spectrum in segment acquirement, and threshold processing is also introduced to eliminate the bad influence on the acquirement, and thus the best decomposition result of IEWT can be obtained based on feature energy ratio (FER). The loose slipper fault signal of hydraulic pump is tested and verified. The result demonstrates that the proposed method is superior and can extract the fault feature information accurately.

scholarly journals The Influence of Typography on Algorithms that Predict the Speed and Comfort of Reading

Vision ◽  
2020 ◽  
Vol 4 (1) ◽  
pp. 18 ◽  
Author(s):  
Arnold Wilkins ◽  
Katie Smith ◽  
Olivier Penacchio
Keyword(s):  
Fourier Transformation ◽  
Amplitude Spectrum ◽  
Visual Comfort ◽  
Fourier Amplitude ◽  
Font Design ◽  
Spatial Regularity ◽  
Line Separation ◽  
Fourier Amplitude Spectrum

1. The speed with which text can be read is determined in part by the spatial regularity and similarity of vertical letter strokes as assessed by the height of the first peak in the horizontal autocorrelation of the text. The height of this peak was determined for two passages in 20 fonts. The peak was unaffected by the size of the text or its content but was influenced by the font design. Sans serif fonts usually had a lower peak than serif fonts because the presence of serifs usually (but not invariably) resulted in a more even spacing of letter strokes. There were small effects of justification and font-dependent effects of font expansion and compression. 2. The visual comfort of images can be estimated from the extent to which the Fourier amplitude spectrum conforms to 1/f. Students were asked to adjust iBooks to obtain their preferred settings of font and layout. The preference was predicted by the extent to which the Fourier amplitude spectrum approximated 1/f, which in turn was jointly affected by the design of the font, its weight and the ratio of x-height to line separation. Two algorithms based on the autocorrelation and Fourier transformation of text can be usefully applied to any orthography to estimate likely speed and comfort of reading.

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