The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Gang Wang - One of the best experts on this subject based on the ideXlab platform.
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a simple ground motion prediction model for cumulative Absolute Velocity and model validation
Earthquake Engineering & Structural Dynamics, 2013Co-Authors: Gang WangAbstract:SUMMARY Cumulative Absolute Velocity (CAV) is an important ground motion intensity measure used in seismic hazard analysis. Based on the Next Generation Attenuation strong motion database, a simple ground-motion prediction equation is proposed for the geometric mean of as-recorded horizontal components of CAVs using mixed regression analysis. The proposed model employs only four parameters and has a simple functional form. Validation tests are conducted to compare the proposed model with the recently developed Campbell–Bozorgnia (CB10) model using subsets of the strong motion database, as well as several recent earthquakes that are not used in developing the model. It is found that the predictive capability of the proposed model is comparable with the CB10 model, which employs a complex functional form and more parameters. The study also corroborates previous findings that CAV has higher predictability than other intensity measures such as the peak ground acceleration. The high predictability of CAV warrants the use of the proposed simple model as an alternative in seismic hazard analysis. Copyright © 2012 John Wiley & Sons, Ltd.
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intra event spatial correlations for cumulative Absolute Velocity arias intensity and spectral accelerations based on regional site conditions
Bulletin of the Seismological Society of America, 2013Co-Authors: Gang WangAbstract:Abstract Spatial correlations of ground‐motion intensity measures (IMs) are essential for seismic analysis of spatially distributed systems. In this paper, geostatistical analysis is conducted to calculate the spatial correlations for cumulative Absolute Velocity (CAV), Arias intensity (Ia), and spectral accelerations (SA) using a total number of more than 1500 earthquake records from nine recent earthquakes occurred in Taiwan, California, and Japan. The results indicate that the spatial correlations for these IMs are closely related to the regional site conditions, and they can be predicted based on the spatial correlations of shear‐wave Velocity in the top 30 m ( V S 30 ). In general, an IM recorded from a relatively homogeneous regional site condition tends to have a larger spatial correlation range than that from a heterogeneous site condition. Due to their intrinsic similarity to represent the integration of acceleration time histories, CAV and Ia have similar spatial correlation coefficients. Besides, the range of spatial correlation of SA generally increases as the spectral period increases. Simple predictive equations are proposed in this study to quantify the spatial correlations of CAV, Ia, and SA based on regional site conditions. Methods for data correction are also proposed to eliminate artificial correlations due to biased distance scaling and V S 30 estimation in the database. Finally, Monte Carlo method is used to generate spatially distributed IMs. The results demonstrate that the annual frequency of exceedance curves for spatially distributed IMs differ significantly if different ranges of spatial correlations are used.
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empirical correlations between cumulative Absolute Velocity and spectral accelerations from nga ground motion database
Soil Dynamics and Earthquake Engineering, 2012Co-Authors: Gang WangAbstract:Considering multiple ground motion intensity measures is important in seismic hazard analysis and ground motion selection process. Using the NGA strong motion database and recently developed ground-motion prediction models, empirical correlations are developed between cumulative Absolute Velocity (CAV) and spectral accelerations (Sa) at periods from 0.01 to 10 s. The CAV–Sa correlations at long periods are significantly influenced by rupture distance due to modification of the frequency content and duration of the acceleration time history through travel path. Similarly, the presence of strong Velocity pulses in near-source ground motions also affects the correlations at moderate to long periods. On the other hand, the correlations are not particularly sensitive to the earthquake magnitude, orientation of the ground-motion recordings, selection of ground-motion prediction models and local site conditions. Piecewise linear fitting equations are provided to quantify the correlations for various cases. The application of the CAV–Sa correlations in ground motion selection process is also discussed.
Yousef Bozorgnia - One of the best experts on this subject based on the ideXlab platform.
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ground motion models for the horizontal components of arias intensity ai and cumulative Absolute Velocity cav using the nga west2 database
Earthquake Spectra, 2019Co-Authors: Kenneth W. Campbell, Yousef BozorgniaAbstract:We updated our Next Generation Attenuation (NGA)-West1 ground motion models (GMMs) for the horizontal components of Arias intensity (AI) and cumulative Absolute Velocity (CAV) using the functional ...
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a comparison of ground motion prediction equations for arias intensity and cumulative Absolute Velocity developed using a consistent database and functional form
Earthquake Spectra, 2012Co-Authors: Kenneth W. Campbell, Yousef BozorgniaAbstract:Arias intensity (AI) and cumulative Absolute Velocity (CAV) have been proposed as instrumental intensity measures that can incorporate the cumulative effects of ground motion duration and intensity...
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cumulative Absolute Velocity cav and seismic intensity based on the peer nga database
Earthquake Spectra, 2012Co-Authors: Kenneth W. Campbell, Yousef BozorgniaAbstract:Abstract Cumulative Absolute Velocity (CAV) has been proposed as an instrumental index to quantify the potential earthquake damage to structures. We explore this idea further by developing a relationship between the standardized version of CAV and the Japan Meteorological Agency (JMA) and modified Mercalli (MMI) instrumental seismic intensities in order to correlate standardized CAV with the qualitative descriptions of damage in the corresponding macroseismic intensity scales. Such an analysis statistically identifies the threshold values of standardized CAV associated with the onset of damage to buildings of good design and construction inherent in these scales. Based on these results, we suggest that CAV might be used to rapidly assess the potential damage to a general class of conventional structures after an earthquake. However, other ground motion or damage-related parameters might be better suited to quantifying the potential damage to structures of a specific type and size.
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prediction equations for the standardized version of cumulative Absolute Velocity as adapted for use in the shutdown of u s nuclear power plants
Nuclear Engineering and Design, 2011Co-Authors: Kenneth W. Campbell, Yousef BozorgniaAbstract:The U.S. Nuclear Regulatory Commission (USNRC) uses the standardized version of the cumulative Absolute Velocity (CAV) together with the response spectra of the recorded ground motion at a site to determine whether a nuclear power plant must be shut down for inspection after an earthquake. In order to better understand the impact of these criteria on potential plant shutdowns, we used several subsets of the PEER-NGA strong motion database to develop empirical prediction equations between a CAV intensity measure that incorporates these criteria and the geometric mean horizontal component of CAV. This particular approach was used because, after applying the USNRC shutdown criteria, we found that there were an insufficient number of records remaining to reliably develop a ground motion prediction equation (GMPE) for this new CAV intensity measure directly from the physical parameters of an earthquake. We use these prediction equations to demonstrate how a lower-bound value of this intensity measure can be used to prevent non-damaging ground motions from both nearby small-magnitude earthquakes and distant large-magnitude earthquakes from contributing to the ground motion hazard computed from a probabilistic seismic hazard analysis (PSHA). We suggest that the use of a CAV criterion, in addition to a criterion based on either peak ground motion parameters or response spectral ordinates, could also be used to prevent the unnecessary shutdown of nuclear power plants outside of the U.S. Furthermore, with some adjustment, a similar approach could be used to rapidly assess the potential damage to conventional structures after an earthquake to aid in emergency response and loss assessment.
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A Ground Motion Prediction Equation for the Horizontal Component of Cumulative Absolute Velocity (CAV) Based on the PEER-NGA Strong Motion Database:
Earthquake Spectra, 2010Co-Authors: Kenneth W. Campbell, Yousef BozorgniaAbstract:Cumulative Absolute Velocity (CAV), defined as the integral of the Absolute acceleration time series, has been used as an index to indicate the possible onset of structural damage to nuclear power ...
Sandra Rugonyi - One of the best experts on this subject based on the ideXlab platform.
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measurement of Absolute blood flow Velocity in outflow tract of hh18 chicken embryo based on 4d reconstruction using spectral domain optical coherence tomography
Biomedical Optics Express, 2010Co-Authors: Aiping Liu, Xin Yin, Aaron Troyer, Kent L Thornburg, Ruikang K Wang, Sandra RugonyiAbstract:The measurement of blood-plasma Absolute Velocity distributions with high spatial and temporal resolution in vivo is important for the investigation of embryonic heart at its early stage of development. We introduce a novel method to measure Absolute blood flow Velocity based on high speed spectral domain optical coherence tomography (OCT) and apply it to measure velocities across the heart outflow tract (OFT) of a chicken embryo (stage HH18). First, we use the OCT system to acquire 4D [(x,y,z) + t] images of the OFT in vivo. Second, we reconstruct the 4D microstructural images and obtain the orientation of the OFT at its maximum expansion, from which the centerline of the OFT is calculated based on the OFT boundary segmentation. Assuming flow is parallel to the vessel orientation, the obtained centerline indicates the flow direction. Finally, the Absolute flow Velocity is evaluated based on the direction given by the centerline and the axial Velocity obtained from Doppler OCT. Using this method, we compare flow Velocity profiles at various positions along the chicken embryo OFT.
Jessica C Ramellaroman - One of the best experts on this subject based on the ideXlab platform.
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Absolute blood Velocity measured with a modified fundus camera
Journal of Biomedical Optics, 2010Co-Authors: Donald D Duncan, Paul Lemaillet, Mohamed A Ibrahim, Quan Dong Nguyen, Matthias Hiller, Jessica C RamellaromanAbstract:We present a new method for the quantitative estimation of blood flow Velocity, based on the use of the Radon transform. The specific application is for measurement of blood flow Velocity in the retina. Our modified fundus camera uses illumination from a green LED and captures imagery with a high-speed CCD camera. The basic theory is presented, and typical results are shown for an in vitro flow model using blood in a capillary tube. Subsequently, representative results are shown for representative fundus imagery. This approach provides Absolute Velocity and flow direction along the vessel center- line or any lateral displacement therefrom. We also provide an error analysis allowing estimation of confidence intervals for the estimated Velocity. © 2010 Society of Photo-Optical Instrumentation Engineers.
Kenneth W. Campbell - One of the best experts on this subject based on the ideXlab platform.
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ground motion models for the horizontal components of arias intensity ai and cumulative Absolute Velocity cav using the nga west2 database
Earthquake Spectra, 2019Co-Authors: Kenneth W. Campbell, Yousef BozorgniaAbstract:We updated our Next Generation Attenuation (NGA)-West1 ground motion models (GMMs) for the horizontal components of Arias intensity (AI) and cumulative Absolute Velocity (CAV) using the functional ...
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a comparison of ground motion prediction equations for arias intensity and cumulative Absolute Velocity developed using a consistent database and functional form
Earthquake Spectra, 2012Co-Authors: Kenneth W. Campbell, Yousef BozorgniaAbstract:Arias intensity (AI) and cumulative Absolute Velocity (CAV) have been proposed as instrumental intensity measures that can incorporate the cumulative effects of ground motion duration and intensity...
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cumulative Absolute Velocity cav and seismic intensity based on the peer nga database
Earthquake Spectra, 2012Co-Authors: Kenneth W. Campbell, Yousef BozorgniaAbstract:Abstract Cumulative Absolute Velocity (CAV) has been proposed as an instrumental index to quantify the potential earthquake damage to structures. We explore this idea further by developing a relationship between the standardized version of CAV and the Japan Meteorological Agency (JMA) and modified Mercalli (MMI) instrumental seismic intensities in order to correlate standardized CAV with the qualitative descriptions of damage in the corresponding macroseismic intensity scales. Such an analysis statistically identifies the threshold values of standardized CAV associated with the onset of damage to buildings of good design and construction inherent in these scales. Based on these results, we suggest that CAV might be used to rapidly assess the potential damage to a general class of conventional structures after an earthquake. However, other ground motion or damage-related parameters might be better suited to quantifying the potential damage to structures of a specific type and size.
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prediction equations for the standardized version of cumulative Absolute Velocity as adapted for use in the shutdown of u s nuclear power plants
Nuclear Engineering and Design, 2011Co-Authors: Kenneth W. Campbell, Yousef BozorgniaAbstract:The U.S. Nuclear Regulatory Commission (USNRC) uses the standardized version of the cumulative Absolute Velocity (CAV) together with the response spectra of the recorded ground motion at a site to determine whether a nuclear power plant must be shut down for inspection after an earthquake. In order to better understand the impact of these criteria on potential plant shutdowns, we used several subsets of the PEER-NGA strong motion database to develop empirical prediction equations between a CAV intensity measure that incorporates these criteria and the geometric mean horizontal component of CAV. This particular approach was used because, after applying the USNRC shutdown criteria, we found that there were an insufficient number of records remaining to reliably develop a ground motion prediction equation (GMPE) for this new CAV intensity measure directly from the physical parameters of an earthquake. We use these prediction equations to demonstrate how a lower-bound value of this intensity measure can be used to prevent non-damaging ground motions from both nearby small-magnitude earthquakes and distant large-magnitude earthquakes from contributing to the ground motion hazard computed from a probabilistic seismic hazard analysis (PSHA). We suggest that the use of a CAV criterion, in addition to a criterion based on either peak ground motion parameters or response spectral ordinates, could also be used to prevent the unnecessary shutdown of nuclear power plants outside of the U.S. Furthermore, with some adjustment, a similar approach could be used to rapidly assess the potential damage to conventional structures after an earthquake to aid in emergency response and loss assessment.
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A Ground Motion Prediction Equation for the Horizontal Component of Cumulative Absolute Velocity (CAV) Based on the PEER-NGA Strong Motion Database:
Earthquake Spectra, 2010Co-Authors: Kenneth W. Campbell, Yousef BozorgniaAbstract:Cumulative Absolute Velocity (CAV), defined as the integral of the Absolute acceleration time series, has been used as an index to indicate the possible onset of structural damage to nuclear power ...
