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Broadband waveform modeling of moderate earthquakes in the San Francisco Bay Area and preliminary assessment of the USGS 3D seismic velocity model

Broadband waveform modeling of moderate earthquakes in the S...

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作者： Rodgers, Arthur Petersson, N. Anders Nilsson, Stefan Sjögreen, Björn McCandless, Kathleen Atmospheric Earth and Energy Division Chemistry Materials Earth and Life Sciences Directorate Lawrence Livermore National Laboratory 7000 East Avenue L-205 Livermore CA 94551 United States Center for Applied Scientific Computing Computations Directorate Lawrence Livermore National Laboratory 7000 East Avenue L-550 Livermore CA 94551 United States Computer Applications and Research Department Computations Directorate Lawrence Livermore National Laboratory 7000 East Avenue L-463 Livermore CA 94551 United States

Recently, the United States Geologic Survey Earthquake Hazards Program developed a 3D seismic velocity model of Northern California based on geology, including a detailed model of the urbanized San Francisco Bay Area. In this study, we report comparisons of observed three-component broadband (0.03-0.25-Hz) wave-forms with synthetic seismograms computed with the new 3D model using an elastic finite difference method. We selected a set of 12 moderate earthquakes (Mw 4.0-5.1) that occurred within the greater San Francisco Bay Area, having well-constrained source parameters and broadband recordings with high signal-to-noise ratios. The objective of this study was to investigate how well the 3D velocity model predicts observed waveforms and to identify features of the model that may require revision to improve the waveform fits and predictions of ground motions for future events. We show for the 3 September 2000 Yountville earthquake that reported source parameters accurately predict waveforms at two close strong-motion stations (approximately 10 km from the epicenter). By comparing synthetics for the average 1D model GIL7 (Stidham et al., 1999) and the 3D structures we show that the effects of seismic wave propagation in the 3D model become important for frequencies at and above 0.1 Hz (periods less than 10 see). Comparison of observed and synthetic seismograms for the 3D model consistently shows that the model predicts energy arriving earlier than is observed, particularly for the surface waves, indicating that the shear velocities in the upper crust must be reduced. We cross correlated the observed and synthetic waveforms and recorded the delay time and linear correlation for best alignment of the data and delayed synthetic. The results indicate that generally the 3D model predicts the observed waveforms well (mean linear correlations 0.41) and includes features that arise from the interaction of the wave field with 3D structure, especially the major sedimentary basin

关键词： Seismic waves

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Directional change of tracer trajectories in rotating Rayleigh-Bénard convection

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Physical Review E 2018年第6期97卷 063105-063105页

作者： Kim M. J. Alards Hadi Rajaei Rudie P. J. Kunnen Federico Toschi Herman J. H. Clercx Fluid Dynamics Laboratory Department of Applied Physics Eindhoven University of Technology P.O. Box 513 5600 MB Eindhoven The Netherlands Centre of Analysis Scientific Computing and Applications W&I Department of Mathematics and Computer Science Eindhoven University of Technology P.O. Box 513 5600 MB Eindhoven The Netherlands Istituto per le Applicazioni del Calcolo Consiglio Nazionale delle Ricerche Via dei Taurini 19 00185 Rome Italy

The angle of directional change of tracer trajectories in rotating Rayleigh-Bénard convection is studied as a function of the time increment τ between two instants of time along the trajectories, both experimentally and with direct numerical simulations. Our aim is to explore the geometrical characterization of flow structures in turbulent convection in a wide range of timescales and how it is affected by background rotation. We find that probability density functions (PDFs) of the angle of directional change θ(t,τ) show similar behavior as found in homogeneous isotropic turbulence, up to the timescale of the large-scale coherent flow structures. The scaling of the averaged (over particles and time) angle of directional change Θ(τ)=〈|θ(t,τ)|〉 with τ shows a transition from the ballistic regime [Θ(τ)∼τc with c=1] for τ≲τη, with τη the Kolmogorov timescale, to a scaling with smaller exponent c for τη≲τ≲TL, with TL the Lagrangian integral timescale. This scaling exponent is approximately constant in the weakly rotating regime (Rossby number Ro≳2.5) and is decreasing for increasing rotation rates when Ro≲2.5. We show that this trend in the scaling exponent is related with the large-scale coherent structures in the flow; the large-scale circulation for Ro≳2.5 and vertically aligned vortices emerging from the boundary layers (BLs) near the top and bottom plates and penetrating into the bulk for Ro≲2.5. In the viscous BLs, the PDFs of θ(t,τ) and scaling properties of Θ(τ) are in general different from those measured in the bulk and depend on the type of boundary layer, in particular whether the BL is of Prandtl-Blasius type (Ro≳2.5) or of Ekman type (Ro≲2.5). When it is of Ekman type, a stronger dynamic coupling exists between the BL and the bulk of the flow, resulting in similar scaling exponents in BL and bulk.

关键词： Rayleigh-Bénard convection Rotating geophysical flows

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A Hybrid Solution for Secure Privacy-Preserving Cloud Storage & Information Retrieval

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Human-centric computing and Information Sciences 2023年 13卷

作者： Kumar, Ankit Aljrees, Turki Hsieh, Sun-Yuan Singh, Kamred Udham Singh, Teekam Raja, Linesh Samriya, Jitendra Kumar Mundotiya, Rajesh Kumar Department of Computer Engineering & Applications GLA University UP Mathura India College of Computer Science and Engineering University of Hafr Al-Batin Eastern Province Saudi Arabia Department of Computer Science and Information Engineering Institute of Medical Information Institute of Manufacturing Information and Systems Center for Innovative FinTech Business Models and International Center for the Scientific Development of Shrimp Aquaculture National Cheng Kung University Tainan Taiwan School of Computing Graphic Era Hill University Dehradun India Department of Computer Science and Information Engineering National Cheng Kung University Tainan Taiwan Department of Computer Science and Engineering Graphic Era Deemed to be University Dehradun India Department of Computer Application Manipal University Jaipur Jaipur India Department of Computer Science and Engineering National Institute of Technology Delhi Delhi India School of Computer Science University of Petroleum and Energy Studies Dehradun India

Cloud storage is an emerging archetype used by businesses for data storage. Clients require easy access to data in the cloud, which helps clients with limited computing power move their high-value, high-risk principle jobs to the cloud. The primary concern of this study is towards flawless verifying, checking data bundles, and determining modules to carry out the project. As discussed at several research platforms, each client is concerned about data storage and retrieval. Data security is critical in cloud computing, and thus monitoring has evolved into a vigilance that abstracts the monitoring process. Request made by clients for security planning is always computationally exclusive. As a result, each customer is concerned as to their verified condition. This paper will highlight a secure cloud communication method for client data to address the afore-mentioned issues. Synchronization creates secret hare keys, combined with a model-encrypted data packet sent to the cloud. These secure data are then sent over a public network, subject to monitoring to avert data leakage to an unauthorized party. They lack the cohesion to outsource data storage to the cloud deliberately. As an outcome of this model's distribution, the perception of authorized data owners would be changed regarding cloud storage up to 97.6%, addressing the trust issues between data owners and cloud ace affiliations © 2023, Human-centric computing and Information *** Rights Reserved.

关键词： Cryptography

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Making advanced scientific algorithms and big scientific data management more accessible 14

Making advanced scientific algorithms and big scientific dat...

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Computational Imaging XIV 2016

作者： Venkatakrishnan, S.V. Mohan, K. Aditya Beattie, Keith Correa, Joaquin Dart, Eli Deslippe, Jack R. Hexemer, Alexander Krishnan, Harinarayan MacDowell, Alastair A. Marchesini, Stefano Patton, Simon J. Perciano, Talita Sethian, James A. Stromsness, Rune Tierney, Brian L. Tull, Craig E. Ushizima, Daniela Parkinson, Dilworth Y. Center for Advanced Mathematics for Energy Research Applications Lawrence Berkeley National Lab BerkeleyCA94720 United States Advanced Light Source Lawrence Berkeley National Lab BerkeleyCA94720 United States School of Electrical and Computer Engineering Purdue University PurdueIN47907 United States Computational Research Division Lawrence Berkeley National Lab BerkeleyCA94720 United States National Energy Research Scientific Computing Center BerkeleyCA94720 United States Energy Sciences Network BerkeleyCA94720 United States Department of Mathematics UC Berkeley BerkeleyCA94720 United States

Synchrotrons such as the Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory are user facilities - they are sources of extremely bright X-ray beams, and scientists come from all over the world to perform experiments that require these beams. As the complexity of experiments has increased, and the size and rates of data sets has exploded, managing, analyzing and presenting the data collected at synchrotrons has been an increasing challenge. The ALS has partnered with high performance computing, fast networking, and applied mathematics groups to create a"super-facility", giving users simultaneous access to the experimental, computational, and algorithmic resources to overcome this challenge. This combination forms an efficient closed loop, where data despite its high rate and volume is transferred and processed, in many cases immediately and automatically, on appropriate compute resources, and results are extracted, visualized, and presented to users or to the experimental control system, both to provide immediate insight and to guide decisions about subsequent experiments during beam-time. In this paper, We will present work done on advanced tomographic reconstruction algorithms to support users of the 3D micron-scale imaging instrument (Beamline 8.3.2, hard X-ray micro-tomography). © 2016 Society for Imaging Science and Technology.

关键词： Tomography

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Numerical study of heat transfer in Rayleigh-Bénard convection under rarefied gas conditions

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Physical Review E 2020年第1期102卷 013102-013102页

作者： B. Goshayeshi G. Di Staso F. Toschi H. J. H. Clercx Fluid Dynamics Laboratory and J.M. Burgers Center for Fluid Dynamics Department of Applied Physics Eindhoven University of Technology P. O. Box 513 5600 MB Eindhoven The Netherlands Centre of Analysis Scientific Computing and Applications W&I Department of Mathematics and Computer Science Eindhoven University of Technology P. O. Box 513 5600 MB Eindhoven The Netherlands Istituto per le Applicazioni del Calcolo Consiglio Nazionale delle Ricerche 00185 Rome Italy

The focus of this research is to delineate the thermal behavior of a rarefied monatomic gas confined between horizontal hot and cold walls, physically known as rarefied Rayleigh-Bénard (RB) convection. Convection in a rarefied gas appears only for high temperature differences between the horizontal boundaries, where nonlinear distributions of temperature and density make it different from the classical RB problem. Numerical simulations adopting the direct simulation Monte Carlo approach are performed to study the rarefied RB problem for a cold to hot wall temperature ratio equal to r=0.1 and different rarefaction conditions. Rarefaction is quantified by the Knudsen number, Kn. To investigate the long-time thermal behavior of the system two ways are followed to measure the heat transfer: (i) measurements of macroscopic hydrodynamic variables in the bulk of the flow and (ii) measurements at the microscopic scale based on the molecular evaluation of the energy exchange between the isothermal wall and the fluid. The measurements based on the bulk and molecular scales agreed well. Hence, both approaches are considered in evaluations of the heat transfer in terms of the Nusselt number, Nu. To characterize the flow properly, a modified Rayleigh number (Ram) is defined to take into account the nonlinear temperature and density distributions at the pure conduction state. Then the limits of instability, indicating the transition of the conduction state into a convection state, at the low and large Froude asymptotes are determined based on Ram. At the large Froude asymptote, simulations following the onset of convection showed a relatively small range for the critical Rayleigh (Ram=1770±15) that flow instability occurs at each investigated rarefaction degree. Moreover, we measured the maximum Nusselt values Numax at each investigated Kn. It was observed that for Kn≥0.02, Numax decreases linearly until the transition to conduction at Kn≈0.03, known as the rarefaction limit for

关键词： Flow instability Rarefied flows Rayleigh-Bénard convection

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A PCA-based fuzzy tensor evaluation model for multiple-criteria group decision making

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Applied Soft computing 2023年 132卷

作者： Singh, Meenu Pant, Millie Kong, Lingping Alijani, Zahra Snášel, Václav Department of Applied Mathematics and Scientific Computing Indian Institute of Technology Roorkee Uttarakhand247667 India Mehta Family School of Data Science and Artificial Intelligence Indian Institute of Technology Roorkee Uttarakhand247667 India Faculty of Electrical Engineering and Computer Science VŠB-TU Ostrava Czech Republic Institute for Research and Applications of Fuzzy Modeling University of Ostrava 30. dubna 22 701 03 Ostrava Czech Republic

Multiple-criteria group decision-making (MCGDM) problems mainly consist of multiple factors and multiple Decision Makers (DMs) or Users, for which dimension extension is necessary when considering all the entries of DMs together. Tensor, a generalized form of a matrix, displays a multi-way array item, which is the most suitable and practical way to represent high-dimensional data without losing any information. In this paper, we first reduce the dimension through Principal Component Analysis (PCA), which helps consider the most-informative criteria. Then, we reintroduced the tensor as a fuzzy-form tensor for the MCGDM problem because of user information uncertainty. We choose Interval-valued Neutrosophic Fuzzy numbers (IVNFNs) as the basis for the tensor form because of their ability to distinguish between truth, indeterminacy, and falsity in the data. Lastly, a Generalized Interval-valued Neutrosophic Fuzzy Weighted Geometric (GIVNFWG) operator is defined. Moreover, a generalized framework for fuzzy-form tensors for high-dimensional MCGDM problems is proposed. The feasibility and efficiency of this proposed process is illustrated for a real-world MCGDM problem of ranking the most efficient Third Party Reverse Logistics Partners (3PRLPs), i.e., recycled fiber-based paper mills for the packaging industry. The obtained results are according to the experts and are validated using sensitivity analysis. This analysis facilitates in assessing the impact on the overall ranking performance of 3PRLPs by considering various combinations of environment and technological sub-criteria. © 2022 Elsevier B.V.

关键词： Principal component analysis

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Geometry of tracer trajectories in rotating turbulent flows

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Physical Review Fluids 2017年第4期2卷 044601-044601页

作者： Kim M. J. Alards Hadi Rajaei Lorenzo Del Castello Rudie P. J. Kunnen Federico Toschi Herman J. H. Clercx Fluid Dynamics Laboratory Department of Applied Physics Eindhoven University of Technology P.O. Box 513 5600 MB Eindhoven The Netherlands Istituto Sistemi Complessi Consiglio Nazionale delle Ricerche UOS Sapienza 00185 Rome Italy Centre of Analysis Scientific Computing and Applications W&I Department of Mathematics and Computer Science Eindhoven University of Technology P.O. Box 513 5600 MB Eindhoven The Netherlands Istituto per le Applicazioni del Calcolo Consiglio Nazionale delle Ricerche Via dei Taurini 19 00185 Rome Italy

The geometry of passive tracer trajectories is studied in two different types of rotating turbulent flows; rotating Rayleigh-Bénard convection (RBC; experiments and direct numerical simulations) and rotating electromagnetically forced turbulence (EFT; experiments). This geometry is fully described by the curvature and torsion of trajectories, and from these geometrical quantities we can subtract information on the typical flow structures at different rotation rates. Previous studies, focusing on nonrotating homogeneous isotropic turbulence (HIT), show that the probability density functions (PDFs) of curvature and torsion reveal pronounced power laws. However, the set-ups studied here involve inhomogeneous turbulence, and in RBC the flow near the horizontal plates is definitely anisotropic. We investigate how the typical shapes of the curvature and torsion PDFs, including the pronounced scaling laws, are influenced by this level of anisotropy and inhomogeneity and how this effect changes with rotation. A first effect of rotation is observed as a shift of the curvature and torsion PDFs towards higher values in the case of RBC and towards lower values in the case of EFT. This shift is related to the length scale of typical vortical structures that decreases with rotation in RBC, but increases with rotation in EFT, explaining the opposite shifts of the curvature (and torsion) PDFs. A second remarkable observation is that in RBC the HIT scaling laws are always recovered, as long as the boundary layer (BL) is excluded. This suggests that these scaling laws are very robust and hold as long as we measure in the turbulent bulk. In the BL of the RBC cell, however, the scaling deviates from the HIT prediction for lower rotation rates. This scaling behavior is found to be consistent with the coupling between the boundary layer dynamics and the bulk flow, which changes under rotation. In particular, it is found that the active coupling of the Ekman-type boundary layer with the b

关键词： Rayleigh-Bénard convection Turbulence Convection

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A Stefan problem related to a non-equilibrium shrinking unreacted core model with fast reaction for the sphere

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PAMM 2008年第1期7卷

作者： Adrian Muntean CASA – Center for Analysis Scientific computing and Applications Department of Mathematics and Computer Science TU Eindhoven PO Box 513 5600 MB Eindhoven The Netherlands

The problem studied in this note refers to a substantial part of a larger system of partial differential equations modeling diffusion and fast reaction of a gaseous species A in a reactive spherical porous region. We report on the local existence and uniqueness of weak solutions to the corresponding moving-boundary system containing two coupled mass-balance equations in a moving annulus. Since the system incorporates an explicit description of the velocity of the moving boundary, our formulation resembles to the one-phase Stefan-like problem with kinetic condition. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

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A Comparative Study of Enriched Computational Homogenization Schemes Applied to Two-Dimensional Pattern-Transforming Elastomeric Mechanical Metamaterials

arXiv

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arXiv 2023年

作者： Sperling, S.O. Guo, T. Peerlings, R.H.J. Kouznetsova, V.G. Geers, M.G.D. Rokoš, O. Mechanics of Materials Department of Mechanical Engineering Eindhoven University of Technology P.O. Box 513 Eindhoven5600 MB Netherlands Centre for Analysis Scientific Computing and Applications Department of Mathematics and Computer Science Eindhoven University of Technology P.O. Box 513 Eindhoven5600 MB Netherlands Department of Mechanics Faculty of Civil Engineering Czech Technical University in Prague Thákurova 7 Prague 6166 29 Czech Republic

Elastomeric mechanical metamaterials exhibit unconventional behaviour, emerging from their microstructures often deforming in a highly nonlinear and unstable manner. Such microstructural pattern transformations lead to non-local behaviour and induce abrupt changes in the effective properties, beneficial for engineering applications. To avoid expensive simulations fully resolving the underlying microstructure, homogenization methods are employed. In this contribution, a systematic comparative study is performed, assessing the predictive capability of several computational homogenization schemes in the realm of two-dimensional elastomeric metamaterials with a square stacking of circular holes. In particular, classical first-order and two enriched schemes of second-order and micromorphic computational homogenization type are compared with ensemble-averaged full direct numerical simulations on three examples: uniform compression and bending of an infinite specimen, and compression of a finite specimen. It is shown that although the second-order scheme provides good qualitative predictions, it fails in accurately capturing bifurcation strains and slightly over-predicts the homogenized response. The micromorphic method provides the most accurate prediction for tested examples, although soft boundary layers induce large errors at small scale ratios. The first-order scheme yields good predictions for high separations of scales, but suffers from convergence issues, especially when localization occurs. © 2023, CC BY.

关键词： Homogenization method

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A complete flux scheme for the stationary advection-diffusion-reaction equation

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PAMM 2008年第1期7卷

作者： J.H.M. ten Thije Boonkkamp Centre for Analysis Scientific Computing and Applications Department of Mathematics and Computer Science Eindhoven University of Technology PO Box 513 5600 MB Eindhoven The Netherlands

Expressions for the numerical flux of a conservation law of advection-diffusion-reaction type are derived from a local solution of the entire conservation law, including the source term. The resulting complete flux scheme is given for one-dimensional (in Cartesian and spherical coordinates) and two-dimensional model equations. Combined with a finite volume method, the numerical scheme is second order accurate, uniformly in the Peclet numbers. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

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