scholarly journals Research of the microseismicity location algorithm

2021 ◽  
pp. 32-41
Author(s):  
S. S. Abramenkov ◽  
T. A. Stupina ◽  
I. Yu. Koulakov
Keyword(s):  
Robustness Analysis ◽  
Back Projection ◽  
Seismic Emission ◽  
Location Algorithm ◽  
Microseismic Events ◽  
Comparative Stability

In this paper, we propose the algorithm for locating microseismic events by the method of directed summation of energy envelopes over a network of stations. The algorithm is based on a back projection technology, which allows visualizing the intensity of seismic emission by layer. A comparative stability and robustness analysis of the proposed method with the method using the semblance is carried out.

Microseismic events on the Åknes rockslide in Norway located by a back-projection approach

2019 ◽  
Vol 24 (1) ◽  
pp. 55-74
Author(s):  
Tomáš Fischer ◽  
Daniela Kühn ◽  
Michael Roth
Keyword(s):  
Back Projection ◽  
Microseismic Events ◽  
Projection Approach

A linearity test for thick specimens imaged by HVEM over a 180° angular range

1991 ◽  
Vol 49 ◽  
pp. 552-553
Author(s):  
Yu Liu
Keyword(s):  
Phase Contrast ◽  
Three Dimensional ◽  
Angular Range ◽  
Two Dimensional ◽  
Back Projection ◽  
Line Integral ◽  
Exponential Law ◽  
Transmission Electron ◽  
Absorption Law ◽  
Linearity Test

The image obtained in a transmission electron microscope is the two-dimensional projection of a three-dimensional (3D) object. The 3D reconstruction of the object can be calculated from a series of projections by back-projection, but this algorithm assumes that the image is linearly related to a line integral of the object function. However, there are two kinds of contrast in electron microscopy, scattering and phase contrast, of which only the latter is linear with the optical density (OD) in the micrograph. Therefore the OD can be used as a measure of the projection only for thin specimens where phase contrast dominates the image. For thick specimens, where scattering contrast predominates, an exponential absorption law holds, and a logarithm of OD must be used. However, for large thicknesses, the simple exponential law might break down due to multiple and inelastic scattering.

PEMBELAJARAN SIMULASI PENCITRAAN CT DENGAN MENGGUNAKAN PRINSIP REKONSTRUKSI CITRA DALAM SOFTWARE MATLAB

2015 ◽  
Vol 8 (3) ◽  
pp. 161
Author(s):  
Samuel Gideon
Keyword(s):  
Image Reconstruction ◽  
Ct Imaging ◽  
The Body ◽  
Reconstruction Technique ◽  
Imaging Features ◽  
Back Projection ◽  
Cross Sectional ◽  
Low Contrast ◽  
Image Reconstruction Technique ◽  
Imaging Algorithms

This research was conducted as a learning alternatives for study of CT (computed tomograpghy) imaging using image reconstruction technique which are inversion matrix, back projection and filtered back projection. CT imaging can produce images of objects that do not overlap. Objects more easily distinguishable although given the relatively low contrast. The image is generated on CT imaging is the result of reconstruction of the original object. Matlab allows us to create and write imaging algorithms easily, easy to undersand and gives applied and exciting other imaging features. In this study, an example cross-sectional image recon-struction performed on the body of prostate tumors using. With these methods, medical prac-titioner (such as oncology clinician, radiographer and medical physicist) allows to simulate the reconstruction of CT images which almost resembles the actual CT visualization techniques.Keywords : computed tomography (CT), image reconstruction, Matlab

G × E interaction studies in relation to heterosis and stability of grain yield in maize (Zea mays L.)

2020 ◽  
Vol 80 (03) ◽  
Author(s):  
K. Sumalini ◽  
T. Pradeep ◽  
D. Sravani
Keyword(s):  
Grain Yield ◽  
Zea Mays L ◽  
Yield Stability ◽  
Superior Performance ◽  
Dominant Effect ◽  
Stability Parameters ◽  
Hybrid Classes ◽  
Maize Inbreds ◽  
Comparative Stability ◽  
Potential Use

Interaction of homozygous inbreds and heterozygous single, three way and double crosses with environment had shown a differential response in achieving yield stability. Seven diverse maize inbreds, their 21 single crosses and 105 each of three way and double crosses obtained through diallel were evaluated for twelve characters across three diverse locations to estimate comparative stability of homozygous and heterozygous genotypes for grain yield. Contrasts in heterobeltiosis, combining ability and stability parameters in three environments and interaction effects were observed. Gain in heterobeltiosis (%) for grain yield was observed with decreased environmental quality in different hybrid classes suggesting that heterozygous hybrids are more stable due to individual buffering in single crosses and both individual and population buffering in case of three way and double crosses. Significant increase in SCA effects was observed in moderate environment at Hyderabad rather than at high yielding environment Palem. Significant G × E and Environment (linear) in all the crosses was observed for grain yield suggesting the effect of environment and its pre dominant effect on grain yield. Stability of hybrids was attributed to their superior performance over the parents in low yielding environment. Thus the potential use of selected heterozygous hybrids would allow under diverse environments is suggested to mitigate losses arising out of climate change.

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