Comparison of the application of the Hough Transform method (characterization of the SON section in seismic spectrograms) at two different sites (VdlS and Ryggfonn) to study the evolution of avalanches.

2020 ◽  
Author(s):  
Emma Suriñach ◽  
Elsa Leticia Flores-Márquez
Keyword(s):  
Data Processing ◽  
Hough Transform ◽  
Seismic Signals ◽  
Snow Avalanches ◽  
Experimental Site ◽  
Transform Method ◽  
Wet Snow ◽  
Topographic Characteristics ◽  
A Site

<p>Recently, a method applying the Hough Transform was used to obtain the numerical parameters of the shape of the SON section of the spectrograms  of the seismic signals generated by snow avalanches at the experimental site of Vallée de la Sion (VdlS, Valais, Switzerland) (SFL, Davos). The avalanches were of different size and type (powder-snow, transitional and wet-snow) descending along the same path and recorded at two different locations 690 m of distance between them on the path. This helped us to estimate the evolution of the avalanche speed along the path from the starting zone to the run-out zone. We obtained different spectrogram definition parameters according to the type of avalanche.</p><p>We apply the same methodology to the seismic signals generated by avalanches at the Ryggfonn experimental site (NGI, Oslo). The avalanches were dry/mixed and dry/dense and occurred in the period (2004-2008). They were recorded in a site along the path. The instrumental conditions, characteristics of the raw data, and the data processing were like those of VdLS. However, the topographic characteristics of the site were different. At the Ryggfonn site, the distance between the starting zone and the sensor was 1640 m (985 in VdlS) and the vertical drop was 800 m (700 m in VdLS).</p><p>We present and compare the results obtained to validate a possible application of the method used to VdlS to other places and topographic conditions.</p><p>This research was funded by the CHARMA (CGL2013–40828–R) and the PROMONTEC projects (CGL2017-84720-R) of the Spanish Ministry of Economy, Industry and Competitiveness (MINEICO-FEDER) and RISKNAT group (2014GR/1243).</p>

scholarly journals Robust nanobubble and nanodroplet segmentation in atomic force microscope images using the spherical Hough transform

2017 ◽  
Vol 8 ◽  
pp. 2572-2582 ◽  
Author(s):  
Yuliang Wang ◽  
Tongda Lu ◽  
Xiaolai Li ◽  
Shuai Ren ◽  
Shusheng Bi
Keyword(s):  
Atomic Force Microscope ◽  
Hough Transform ◽  
Morphological Characterization ◽  
Automated Segmentation ◽  
Transform Method ◽  
Atomic Force ◽  
Robust Segmentation ◽  
Segmentation Methods ◽  
Boundary Optimization

Interfacial nanobubbles (NBs) and nanodroplets (NDs) have been attracting increasing attention due to their potential for numerous applications. As a result, the automated segmentation and morphological characterization of NBs and NDs in atomic force microscope (AFM) images is highly awaited. The current segmentation methods suffer from the uneven background in AFM images due to thermal drift and hysteresis of AFM scanners. In this study, a two-step approach was proposed to segment NBs and NDs in AFM images in an automated manner. The spherical Hough transform (SHT) and a boundary optimization operation were combined to achieve robust segmentation. The SHT was first used to preliminarily detect NBs and NDs. After that, the so-called contour expansion operation was applied to achieve optimized boundaries. The principle and the detailed procedure of the proposed method were presented, followed by the demonstration of the automated segmentation and morphological characterization. The result shows that the proposed method gives an improved segmentation result compared with the thresholding and circle Hough transform method. Moreover, the proposed method shows strong robustness of segmentation in AFM images with an uneven background.

scholarly journals Estimation of Avalanche Development and Frontal Velocities Based on the Spectrogram of the Seismic Signals Generated at the Vallée de la Sionne Test Site

Geosciences ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 113 ◽  
Author(s):  
Emma Suriñach ◽  
Elsa Leticia Flores-Márquez ◽  
Pere Roig-Lafon ◽  
Glòria Furdada ◽  
Mar Tapia
Keyword(s):  
Doppler Radar ◽  
Test Site ◽  
Polar Coordinates ◽  
Measured Signal ◽  
Seismic Signals ◽  
Snow Avalanches ◽  
Signal Onset ◽  
Theoretical Function ◽  
Wet Snow ◽  
Radar Measurements

The changes in the seismic signals generated by avalanches recorded at three sites along a path at the Vallée de la Sionne (VdlS) experimental site are presented. We discuss and correlate the differences in the duration, signal amplitudes, and frequency content of the sections (Signal ONset (ON), Signal Body (SBO), and Signal TAil and Signal ENd STA-SEN) of the spectrograms with the evolution of the powder, transitional and wet snow avalanches along a path. The development of the avalanche front was quantified using the exponential function in time F (t) = K’ exp (β t) fitted to the shape of the signal ONset (SON section of the spectrogram. The speed of the avalanche front is contained in β. To this end, a new method was developed. The three seismic components were converted into one seismic component (FS), when expressing the vector in polar coordinates. We linked the theoretical function of the shape of the FS-SON section of the spectrogram to the numerical coefficients of its shape after considering the spectrogram as an image. This allowed us to obtain the coefficients K’ and β. For this purpose, the Hough Transform (HT) was applied to the image. The values of the resulting coefficients K’ and β are included in different ranges in accordance with the three types of avalanche. Curves created with these coefficients enable us to estimate the development of the different avalanche types along the path. Our results show the feasibility of classifying the type of avalanche through these coefficients. Average speeds of the avalanches approaching the recording sites were estimated. The speed values of wet and transitional avalanches are consistent with those derived from GEODAR (GEOphysical Doppler radAR) measurements, when available. The absence of agreement in the speed values obtained from seismic signals and GEODAR measurements for powder snow avalanches indicates, for this type of avalanche, a different source of the measured signal. Hence, the use of the two measuring systems proves to be complementary.

Evolute-based Hough transform method for characterization of ellipsoids

2013 ◽  
Vol 249 (3) ◽  
pp. 159-164 ◽  
Author(s):  
B. KAYTANLI ◽  
M.T. VALENTINE
Keyword(s):  
Hough Transform ◽  
Transform Method

scholarly journals Nystagmus Estimation for Dizziness Diagnosis by Pupil Detection and Tracking Using Mexican-Hat-Type Ellipse Pattern Matching

Healthcare ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 885
Author(s):  
Yoanda Alim Syahbana ◽  
Yokota Yasunari ◽  
Morita Hiroyuki ◽  
Aoki Mitsuhiro ◽  
Suzuki Kanade ◽  
...  
Keyword(s):  
Pattern Matching ◽  
Hough Transform ◽  
University Hospital ◽  
Transform Method ◽  
Data Set ◽  
Medical Specialists ◽  
Detection And Tracking ◽  
Mexican Hat ◽  
Pupil Detection ◽  
In The Wild

The detection of nystagmus using video oculography experiences accuracy problems when patients who complain of dizziness have difficulty in fully opening their eyes. Pupil detection and tracking in this condition affect the accuracy of the nystagmus waveform. In this research, we design a pupil detection method using a pattern matching approach that approximates the pupil using a Mexican hat-type ellipse pattern, in order to deal with the aforementioned problem. We evaluate the performance of the proposed method, in comparison with that of a conventional Hough transform method, for eye movement videos retrieved from Gifu University Hospital. The performance results show that the proposed method can detect and track the pupil position, even when only 20% of the pupil is visible. In comparison, the conventional Hough transform only indicates good performance when 90% of the pupil is visible. We also evaluate the proposed method using the Labelled Pupil in the Wild (LPW) data set. The results show that the proposed method has an accuracy of 1.47, as evaluated using the Mean Square Error (MSE), which is much lower than that of the conventional Hough transform method, with an MSE of 9.53. We conduct expert validation by consulting three medical specialists regarding the nystagmus waveform. The medical specialists agreed that the waveform can be evaluated clinically, without contradicting their diagnoses.

Effect of Humic Preparation ‟BIO-Don” on the Content Nutrients in the Soil and the Quality of Cherries

2021 ◽  
pp. 52-58
Author(s):  
Olga S. Bezuglova ◽  
Artem E. Popov ◽  
Marina N. Dubinina ◽  
Pavel N. Skripnikov
Keyword(s):  
Work Experience ◽  
Fruit Trees ◽  
Soluble Solids ◽  
Experimental Site ◽  
Control Option ◽  
Mobile Phosphorus ◽  
Open Ground ◽  
Working Solution ◽  
A Site

The work deals with the study of the influence of humic preparation ‟BIO-Don” on indicators of soil fertility, the enzymatic activity of Сalcic Chernozem (Pachic) at the experimental site, as well as on the productivity and quality of fruit crops, for example, cherries varieties Talisman and Vasilisa in terms of work experience in the open ground in the territory of «Agrofirm “the Red garden”». Treatment of fruit trees was carried out once by drip irrigation in a dosage of 300 l/ha of working solution with a concentration of gp 0.008 g/l for carbon, soil samples were taken before treatment, two weeks and a month after the application of the humic preparation, a site without the use of “BIO-Don” was used as a control option. The treatment of plants with a humic preparation increases the activity of the enzymes catalase, invertase and phosphatase, especially during the period of mass ripening of fruits. Accordingly, at the same time, the content of mobile phosphorus and exchangeable potassium decreases, which is due to the increased removal of these elements by plants. Chemical analysis of fruit products for the content of soluble solids and titrated acidity revealed a statistically significant increase in these indicators in fruits from areas treated with humic preparation, which is manifested by their greater taste saturation.

Functional and Structural Characterization of Acquired Pan-Aminoglycoside Resistance 16S rRNA Methyltransferase NpmB1

2021 ◽  
Author(s):  
Akito Kawai ◽  
Masahiro Suzuki ◽  
Kentaro Tsukamoto ◽  
Yusuke Minato ◽  
Yohei Doi
Keyword(s):  
Amino Acid ◽  
16S Rrna ◽  
Amino Acid Identity ◽  
Single Amino Acid ◽  
Aminoglycoside Resistance ◽  
E Coli ◽  
The United Kingdom ◽  
Amino Acid Variant ◽  
A Site

Post-translational methylation of the A site of 16S rRNA at position A1408 leads to pan-aminoglycoside resistance encompassing both 4,5- and 4,6-disubstituted 2-deoxystreptamine (DOS) aminoglycosides. To date, NpmA is the only acquired enzyme with such function. Here, we present function and structure of NpmB1 whose sequence was identified in Escherichia coli genomes registered from the United Kingdom. NpmB1 possesses 40% amino acid identity with NpmA1 and confers resistance to all clinically relevant aminoglycosides including 4,5-DOS agents. Phylogenetic analysis of NpmB1 and NpmB2, its single amino acid variant, revealed that the encoding gene was likely acquired by E. coli from a soil bacterium. The structure of NpmB1 suggests that it requires a structural change of the β6/7 linker in order to bind to 16S rRNA. These findings establish NpmB1 and NpmB2 as the second group of acquired pan-aminoglycoside resistance 16S rRNA methyltransferases.

Numerical simulations of wet snow avalanches: interplay between cohesion and friction

2021 ◽  
Author(s):  
Guillaume Chambon ◽  
Thierry Faug ◽  
Mohamed Naaim
Keyword(s):  
Numerical Simulations ◽  
Flow Regimes ◽  
Liquid Water Content ◽  
Snow Avalanches ◽  
Shallow Flow ◽  
Distinctive Features ◽  
Wide Range ◽  
Wet Snow ◽  
Sensitivity Studies ◽  
Avalanche Flow

<p>Wet snow avalanches present distinctive features such as unusual trajectories, peculiar deposit shapes, and a rheological behavior displaying a combination of granular and pasty features depending on the actual snow liquid water content. Complex transitions between dry (cold) and wet (hot) flow regimes can also occur during a single avalanche flow. In an attempt to account for this complexity, we report on numerical simulations of avalanches using a frictional-cohesive rheology implemented in a depth-averaged shallow-flow model. Through extensive sensitivity studies on synthetic and real topographies, we show that cohesion plays a key role to enrich the physics of the simulated flows, and to represent realistic avalanche behaviors. First, when coupled to a proper treatment of the yielding criterion, cohesion provides a way to define objective stopping criteria for the flow, independently of the issues incurred by artificial diffusion of the numerical scheme. Second, and more importantly, the interplay between cohesion and friction gives raise to a variety of nontrivial physical effects affecting the dynamics of the avalanches and the morphology of the deposits. The relative weights of frictional and cohesive contributions to the overall stress are investigated as a function of space and time during the propagation, and related to the formation of specific features such as lateral levées, hydraulic jumps, etc. This study represents a first step towards robust avalanches simulations, spanning the wide range of possible flow regimes, through shallow-flow approaches. Future improvements involving more refined cohesion parameterizations will be discussed.</p>

scholarly journals Modelling the system behaviour of wet snow avalanches using an expert system approach for risk management on high alpine traffic roads

2005 ◽  
Vol 5 (6) ◽  
pp. 821-832 ◽  
Author(s):  
A. Zischg ◽  
S. Fuchs ◽  
M. Keiler ◽  
G. Meißl
Keyword(s):  
Risk Management ◽  
Fuzzy Logic ◽  
Expert System ◽  
Temporal Variability ◽  
Hazard Index ◽  
Rule Base ◽  
Spatial And Temporal Variability ◽  
Snow Avalanches ◽  
System Behaviour ◽  
Wet Snow

Abstract. The presented approach describes a model for a rule-based expert system calculating the temporal variability of the release of wet snow avalanches, using the assumption of avalanche triggering without the loading of new snow. The knowledge base of the model is created by using investigations on the system behaviour of wet snow avalanches in the Italian Ortles Alps, and is represented by a fuzzy logic rule-base. Input parameters of the expert system are numerical and linguistic variables, measurable meteorological and topographical factors and observable characteristics of the snow cover. Output of the inference method is the quantified release disposition for wet snow avalanches. Combining topographical parameters and the spatial interpolation of the calculated release disposition a hazard index map is dynamically generated. Furthermore, the spatial and temporal variability of damage potential on roads exposed to wet snow avalanches can be quantified, expressed by the number of persons at risk. The application of the rule base to the available data in the study area generated plausible results. The study demonstrates the potential for the application of expert systems and fuzzy logic in the field of natural hazard monitoring and risk management.

scholarly journals Robust measurements of electric conductivity in polyethylene based materials: measurement setup, data processing and impact of sample preparation

2017 ◽  
Author(s):  
Xiangdong Xu ◽  
M Karlsson ◽  
K. Gaska ◽  
Stanislaw Gubanski ◽  
Henrik Hillborg ◽  
...  
Keyword(s):  
Data Processing ◽  
Electric Conductivity ◽  
External Noise ◽  
Current Data ◽  
Current Level ◽  
Conductivity Measurements ◽  
High Reproducibility ◽  
Robust Measurements ◽  
Good Differentiation

<p>In this work, a measurement setup and an algorithm are introduced that allow for obtaining and processing the current data during standard measurements of electric conductivity in polymeric insulation materials. Robustness of this setup is demonstrated through dc conductivity measurements of low density polyethylene (LDPE) specimens that were prepared by two different techniques, i.e. compression molding and extrusion, at two independent laboratories (at Chalmers and KTH) from the same raw pellets. The results resented in this paper reveal that the implemented data processing algorithm allows for clear separation of the conduction current level and the external noise and thus for good differentiation between the conductivity levels in the investigated material specimens. In addition, a high reproducibility of the results is obtained for the independently manufactured specimens, suggesting the proposed measurement technique is well suitable for characterization of low conducting dielectrics.</p>

Sign in / Sign up

Export Citation Format

Share Document