Automatic Detection of Amplitude-Distorted Samples from Clipped Seismic Waveforms

Abstract Seismic waveforms are essential for seismology but are clipped when their actual amplitudes are too high to be faithfully recorded by seismometers. The clipping effects are popular for both big earthquakes and small earthquakes within a short epicentral distance. Here, we illustrate potential risks of direct usage of clipped waveforms by examining the frequency leakage and show the failure of bandpass filtering for different clipping levels; then we summarize two characteristics of clipped records: (1) The temporal gradient is unusually large around the clipped segment compared with the unclipped portions, and (2) the clipped samples cluster into one segment or several if many samples are involved. Next, we propose three criteria for distinguishing clipped samples from the perfect samples based on these two characteristics. Finally, we design a numerical algorithm for automatic detection of clipped samples using constraints on the gradient, amplitude, and gradient-varying range. Numerical experiments show the excellent performance of our algorithm on automatically detecting the clipped samples. Our algorithm seamlessly integrates all necessary constraints for both flat-top type and back-to-zero type and thus can correctly recognize these two types simultaneously; in addition, it is basically data driven and thus can work well without considering seismometer configuration and instrument type, which would be helpful for real-time detection of clipped records without interruption from human operations. As a robust and swift tool of automatic detection on amplitude-clipped samples, our algorithm could identify most typical clipped records and reduce potential risks due to using unrecognizable clipped waveforms; furthermore, it would be helpful for fast detection and possible restoration of clipped waveforms in the presence of huge volumes of data.

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Mo calculations from a generalized AR parameter method for WWSSN instruments

Bulletin of the Seismological Society of America ◽

10.1785/bssa0690020329 ◽

1979 ◽

Vol 69 (2) ◽

pp. 329-351

Author(s):

Barbara Radovich Williams

Keyword(s):

Epicentral Distance ◽

Wave Train ◽

Digital Data ◽

Parameter Method ◽

Recording Instrument ◽

Mo Calculations ◽

Routine Procedure ◽

Instrument Type ◽

Wide Range ◽

Single Calibration

abstract A single calibration curve which relates seismic moment (Mo to the AR parameter, a time domain sum of the area under the surface-wave envelope, has been found applicable to 20 WWSSN long-period instruments recording surface waves over predominantly oceanic paths of up to 17,000 km epicentral distance, and Ms up to 8.0. The method is easy and Mo estimates are obtained in a routine procedure with errors of a factor of 2 for continental events and a factor of 3 for oceanic events. Analog or digital data can be used from a few stations with only an approximate knowledge of the recording instrument, type of path, and mechanism of the event. Theoretical Mo versus AR curves are derived from the average spectral theory of Geller (1976) and the empirically determined curve is consistent with the predicted. The AR method is shown to be more sensitive to longer period contributions to the wave train as the event size increases, establishing its usefulness for studying earthquakes with a wide range of Ms values. The method is applied to 12 events occurring in 1974 to 1975 with unknown Mo.

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A fast detection and grasping method for mobile manipulator based on improved faster R-CNN

Industrial Robot the international journal of robotics research and application ◽

10.1108/ir-07-2019-0150 ◽

2020 ◽

Vol 47 (2) ◽

pp. 167-175

Author(s):

Hui Zhang ◽

Jinwen Tan ◽

Chenyang Zhao ◽

Zhicong Liang ◽

Li Liu ◽

...

Keyword(s):

Design Methodology ◽

Detection Efficiency ◽

The Self ◽

Mobile Manipulator ◽

Time Cost ◽

Excellent Performance ◽

Data Set ◽

Content Type ◽

Fast Detection ◽

And Performance

Purpose This paper aims to solve the problem between detection efficiency and performance in grasp commodities rapidly. A fast detection and grasping method based on improved faster R-CNN is purposed and applied to the mobile manipulator to grab commodities on the shelf. Design/methodology/approach To reduce the time cost of algorithm, a new structure of neural network based on faster R CNN is designed. To select the anchor box reasonably according to the data set, the data set-adaptive algorithm for choosing anchor box is presented; multiple models of ten types of daily objects are trained for the validation of the improved faster R-CNN. The proposed algorithm is deployed to the self-developed mobile manipulator, and three experiments are designed to evaluate the proposed method. Findings The result indicates that the proposed method is successfully performed on the mobile manipulator; it not only accomplishes the detection effectively but also grasps the objects on the shelf successfully. Originality/value The proposed method can improve the efficiency of faster R-CNN, maintain excellent performance, meet the requirement of real-time detection, and the self-developed mobile manipulator can accomplish the task of grasping objects.

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New Candidate Ultralow-Velocity Zone Locations from Highly Anomalous SPdKS Waveforms

Minerals ◽

10.3390/min10030211 ◽

2020 ◽

Vol 10 (3) ◽

pp. 211 ◽

Cited By ~ 2

Author(s):

Michael S. Thorne ◽

Surya Pachhai ◽

Kuangdai Leng ◽

June K. Wicks ◽

Tarje Nissen-Meyer

Keyword(s):

Pacific Northwest ◽

Amazon Basin ◽

Epicentral Distance ◽

Good Evidence ◽

High Iron Content ◽

Northern Mexico ◽

Partial Melt ◽

Seismic Waveforms ◽

The Pacific ◽

Velocity Zone

Ultralow-velocity zones (ULVZs) at the core–mantle boundary (CMB) represent some of the most preternatural features in Earth’s mantle. These zones most likely contain partial melt, extremely high iron content ferropericlase, or combinations of both. We analyzed a new collection of 58,155 carefully processed and quality-controlled broadband recordings of the seismic phase SPdKS in the epicentral distance range from 106° to 115°. These data sample 56.9% of the CMB by surface area. From these recordings we searched for the most anomalous seismic waveforms that are indicative of ULVZ presence. We used a Bayesian approach to identify the regions of the CMB that have the highest probability of containing ULVZs, thereby identifying sixteen regions of interest. Of these regions, we corroborate well-known ULVZ existence beneath the South China Sea, southwest Pacific, the Samoa hotspot, the southwestern US/northern Mexico, and Iceland. We find good evidence for new ULVZs beneath North Africa, East Asia, and north of Papua New Guinea. We provide further evidence for ULVZs in regions where some evidence has been hinted at before beneath the Philippine Sea, the Pacific Northwest, and the Amazon Basin. Additional evidence is shown for potential ULVZs at the base of the Caroline, San Felix and Galapagos hotspots.

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The Automatic Detection Technology for the Surface Defects of Automobile Engine Cylinder

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.693.1458 ◽

2016 ◽

Vol 693 ◽

pp. 1458-1465 ◽

Cited By ~ 1

Author(s):

Jin Jun Ji ◽

C. Ye

Keyword(s):

Surface Defects ◽

Automatic Detection ◽

Geometric Distortion ◽

Casting Defects ◽

Automobile Engine ◽

Fast Detection ◽

Detection Technology ◽

Engine Cylinder ◽

Defect Area ◽

Cylinder Bore

In view of the casting defects of the automobile engine cylinder, the automatic detection technology for the surface defects of cylinder was investigated in this study. Moreover, a system was designed to automatically detect the surface defects of engine cylinder bore basing on machine vision technology. The pixels of the bottom circle and top circle of cylinder bore were effectively extracted using a Hough transform-based fast detection circle algorithm; Aiming to solve the inconvenience in observation and measurement as well as the obvious geometric distortion presented in annular image, an algorithm, in which annulus was extended into rectangular, was put forward. Experiment results proved that this algorithm was fast and efficient and showed lower mean error in calculating annular defect area.

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Computer programs for the calculation of x-ray intensities emitted by elements in multi-layer structures

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100134685 ◽

1990 ◽

Vol 48 (2) ◽

pp. 216-217

Author(s):

G.F. Bastin ◽

H.J.M. Heijligers ◽

J.M. Dijkstra

Keyword(s):

Software Package ◽

Light Element ◽

Matrix Correction ◽

Excellent Performance ◽

Element Analysis ◽

X Ray ◽

Know How ◽

Accurate Knowledge ◽

Layer Structures ◽

Bulk Matrix

For the calculation of X-ray intensities emitted by elements present in multi-layer systems it is vital to have an accurate knowledge of the x-ray ionization vs. mass-depth (ϕ(ρz)) curves as a function of accelerating voltage and atomic number of films and substrate. Once this knowledge is available the way is open to the analysis of thin films in which both the thicknesses as well as the compositions can usually be determined simultaneously.Our bulk matrix correction “PROZA” with its proven excellent performance for a wide variety of applications (e.g., ultra-light element analysis, extremes in accelerating voltage) has been used as the basis for the development of the software package discussed here. The PROZA program is based on our own modifications of the surface-centred Gaussian ϕ(ρz) model, originally introduced by Packwood and Brown. For its extension towards thin film applications it is required to know how the 4 Gaussian parameters α, β, γ and ϕ(o) for each element in each of the films are affected by the film thickness and the presence of other layers and the substrate.

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The Role of Shared Decision-Making in Audiologic Rehabilitation

Perspectives on Aural Rehabilitation and Its Instrumentation ◽

10.1044/arri21.1.15 ◽

2014 ◽

Vol 21 (1) ◽

pp. 15-23 ◽

Cited By ~ 6

Author(s):

Helen Pryce ◽

Amanda Hall

Keyword(s):

Decision Making ◽

Shared Decision Making ◽

Behavior Changes ◽

Shared Decision ◽

Patient Centered ◽

Treatment Information ◽

Centered Care ◽

Potential Risks ◽

Audiologic Rehabilitation

Shared decision-making (SDM), a component of patient-centered care, is the process in which the clinician and patient both participate in decision-making about treatment; information is shared between the parties and both agree with the decision. Shared decision-making is appropriate for health care conditions in which there is more than one evidence-based treatment or management option that have different benefits and risks. The patient's involvement ensures that the decisions regarding treatment are sensitive to the patient's values and preferences. Audiologic rehabilitation requires substantial behavior changes on the part of patients and includes benefits to their communication as well as compromises and potential risks. This article identifies the importance of shared decision-making in audiologic rehabilitation and the changes required to implement it effectively.

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