scholarly journals A generalization of the frequency-magnitude relation in the hypothesis of a maximum regional magnitude

2010 ◽  
Vol 29 (1-2) ◽  
Author(s):  
P. COSENTINO ◽  
D. Luzio
Keyword(s):  
Maximum Regional Magnitude ◽  
Frequency Magnitude

Fuzzified time-frequency method for identification and localization of power system faults

2021 ◽  
pp. 1-13
Author(s):  
Pullabhatla Srikanth ◽  
Chiranjib Koley
Keyword(s):  
Power System ◽  
High Accuracy ◽  
Fuzzy Decision ◽  
Frequency Method ◽  
Time Frequency ◽  
Novel Approach ◽  
S Transform ◽  
Different Types ◽  
Power System Faults ◽  
Frequency Magnitude

In this work, different types of power system faults at various distances have been identified using a novel approach based on Discrete S-Transform clubbed with a Fuzzy decision box. The area under the maximum values of the dilated Gaussian windows in the time-frequency domain has been used as the critical input values to the fuzzy machine. In this work, IEEE-9 and IEEE-14 bus systems have been considered as the test systems for validating the proposed methodology for identification and localization of Power System Faults. The proposed algorithm can identify different power system faults like Asymmetrical Phase Faults, Asymmetrical Ground Faults, and Symmetrical Phase faults, occurring at 20% to 80% of the transmission line. The study reveals that the variation in distance and type of fault creates a change in time-frequency magnitude in a unique pattern. The method can identify and locate the faulted bus with high accuracy in comparison to SVM.

Special Items: A Descriptive Analysis

2011 ◽  
Vol 25 (3) ◽  
pp. 511-536 ◽  
Author(s):  
Peter M. Johnson ◽  
Thomas J. Lopez ◽  
Juan Manuel Sanchez
Keyword(s):  
Firm Value ◽  
Temporal Frequency ◽  
Descriptive Analysis ◽  
Financial Statements ◽  
Comprehensive Analysis ◽  
The Other ◽  
Future Earnings ◽  
Special Items ◽  
Increasing Function ◽  
Frequency Magnitude

SYNOPSIS We provide a comprehensive analysis of special items and the characteristics of the firms that recognize them. Our analysis reveals that the temporal frequency, magnitude, and persistence of special items has increased significantly in the last 30 years, and that such increases are primarily driven by negative special items. More recently, however, our evidence is consistent with both a decline in frequency and magnitude of negative special items. On the other hand, we find that the frequency of reporting of positive special items, which remained relatively constant through 2002, has increased in more recent years. We also find strong evidence that subsequent special item reporting is an increasing function of the frequency of “prior” special item reporting. Using a random subsample of firms reporting special items, we document that 22 percent of the amounts reported in Compustat do not reconcile with the amounts reported on the firms' actual financial statements. Our comprehensive analysis should be of interest to regulators, academics, and managers interested in the implications of special items on firm-related consequences such as future earnings and firm value. Our examination can also serve as a catalyst for researchers interested in extending this important area of inquiry.

On the frequency-magnitude relation logN = a ? bM

1970 ◽  
Vol 81 (1) ◽  
pp. 119-123 ◽  
Author(s):  
R. K. S. Chouhan
Keyword(s):  
Frequency Magnitude

scholarly journals Using Waveguides to Model the Dynamic Stiffness of Pre-Compressed Natural Rubber Vibration Isolators

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1703
Author(s):  
Michael Coja ◽  
Leif Kari
Keyword(s):  
Natural Rubber ◽  
Dynamic Stiffness ◽  
Low Frequency ◽  
Complex Problem ◽  
Wide Frequency Range ◽  
Vibration Isolators ◽  
Standard Linear Solid ◽  
Standard Linear ◽  
Frequency Magnitude ◽  
Good Agreement

A waveguide model for a pre-compressed cylindrical natural rubber vibration isolator is developed within a wide frequency range—20 to 2000 Hz—and for a wide pre-compression domain—from vanishing to the maximum in service, that is 20%. The problems of simultaneously modeling the pre-compression and frequency dependence are solved by applying a transformation of the pre-compressed isolator into a globally equivalent linearized, homogeneous, and isotropic form, thereby reducing the original, mathematically arduous, and complex problem into a vastly simpler assignment while using a straightforward waveguide approach to satisfy the boundary conditions by mode-matching. A fractional standard linear solid is applied as the visco-elastic natural rubber model while using a Mittag–Leffler function as the stress relaxation function. The dynamic stiffness is found to depend strongly on the frequency and pre-compression. The former is resulting in resonance phenomena such as peaks and troughs, while the latter exhibits a low-frequency magnitude stiffness increase in addition to peak and trough shifts with increased pre-compressions. Good agreement with nonlinear finite element results is obtained for the considered frequency and pre-compression range in contrast to the results of standard waveguide approaches.

Statistical analysis of seismic data on earthquakes in the area of the Vrancea focus

1970 ◽  
Vol 60 (4) ◽  
pp. 1089-1099
Author(s):  
Ion Săcuiu ◽  
Dan Zorilescu
Keyword(s):  
Statistical Analysis ◽  
Poisson Process ◽  
Seismic Data ◽  
Time Interval ◽  
Generation Process ◽  
Present Contribution ◽  
Important Conclusion ◽  
Distribution Laws ◽  
Frequency Magnitude

abstract The present contribution deals with distribution laws of the earthquake's magnitude, the number of earthquakes (by modelling the generation process as a Poisson process) and the time interval between two successive earthquakes. The most important conclusion arrived at is that in the area of the Vrancea focus the distribution of the magnitudes is lognormal and brings forth a frequency-magnitude relation of the form log λ ( Μ ) = a + b log M + c ( log M ) 2 , not a linear one. A correlation between the magnitude and the time interval of two successive earthquakes is considered and a series of seismic indices are introduced.

Restatement of CSR Reports: Frequency, Magnitude, and Determinants

2017 ◽  
Author(s):  
Matt Pinnuck ◽  
Ajanee Ranasinghe ◽  
Naomi S. Soderstrom ◽  
Joey Zhou
Keyword(s):  
Frequency Magnitude

A geometric frequency–magnitude scaling transition: Measuring b=1.5 for large earthquakes

2012 ◽  
Vol 532-535 ◽  
pp. 167-174 ◽  
Author(s):  
Mark R. Yoder ◽  
James R. Holliday ◽  
Donald L. Turcotte ◽  
John B. Rundle
Keyword(s):  
Magnitude Scaling ◽  
Large Earthquakes ◽  
Frequency Magnitude
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