Jacobo Bielak - Academia.edu (original) (raw)
Papers by Jacobo Bielak
Advanced Modeling and Simulation in Engineering Sciences, 2015
Background: Recently the Double Absorbing Boundary (DAB) method was introduced as a new approach ... more Background: Recently the Double Absorbing Boundary (DAB) method was introduced as a new approach for solving wave problems in unbounded domains. It has common features to each of two types of existing techniques: local high-order Absorbing Boundary Conditions (ABC) and Perfectly Matched Layers (PML). However, it is different from both and enjoys relative advantages with respect to both.
Proceedings of the 2003 ACM/IEEE conference on Supercomputing - SC '03, 2003
Kwan-Liu Ma Aleksander Stompel Department of Computer Science University of California at Davis {... more Kwan-Liu Ma Aleksander Stompel Department of Computer Science University of California at Davis {ma,stompel}@cs.ucdavis.edu ... Jacobo Bielak Omar Ghattas Eui Joong Kim ... Computational Mechanics Laboratory, Department of Civil and Environmental Engineering Carnegie ...
We present a study of the ground motion and resulting amplification in the Mexico City Basin due ... more We present a study of the ground motion and resulting amplification in the Mexico City Basin due to strong earthquakes in the Mexican Pacific Coast. We propose an approximation of the regional structure and Mexico City's basin and analyze their response to two shallow earthquakes generated near the coast. We compare two sets of three dimensional simulations: the first includes
ABSTRACT We present a multiresolution classification framework with semi-supervised learning for ... more ABSTRACT We present a multiresolution classification framework with semi-supervised learning for the indirect structural health mon- itoring of bridges. The monitoring approach envisions a sens- ing system embedded into a moving vehicle traveling across the bridge of interest to measure the modal characteristics of the bridge. To enhance the reliability of the sensing system, we use a semi-supervised learning algorithm and a semi-su- pervised weighting algorithm within a multiresolution clas- sification framework. We show that the proposed algorithm performs significantly better than supervised multiresolution classification. Index
This paper presents a novel method for interpreting data to improve the indirect structural healt... more This paper presents a novel method for interpreting data to improve the indirect structural health monitoring (SHM) of bridges. The research presented in the study is part of an ongoing study aimed at developing a novel SHM paradigm for the health assessment of bridges. In this paradigm, we envision the use of an instrumented vehicle that assesses a bridge's dynamic characteristics while traveling across the bridge. These characteristics are then correlated to the health of the structure by means of advanced signal processing and pattern recognition approaches. In this paper, we present and compare two classification algorithms that locate the presence of damages at well-defined locations on the structure: sparse representation and the Fourier discriminant methods, and find that the sparse representation method provides superior classification accuracy.
We present a parallel octree-based finite el- ement method for large-scale earthquake ground moti... more We present a parallel octree-based finite el- ement method for large-scale earthquake ground motion simulation in realistic basins. The octree representa- tion combines the low memory per node and good cache performance of finite difference methods with the spa- tial adaptivity to local seismic wavelengths characteris- tic of unstructured finite element methods. Several tests are provided to verify the numerical
Bridge Maintenance, Safety and Management, 2012
... We are grateful for this support. We also thank Ranny Zhao and Colin Rutenbar, who participat... more ... We are grateful for this support. We also thank Ranny Zhao and Colin Rutenbar, who participated in the construction of the experimental setup. 8 REFERENCES Cerda F., Garrett J., Bielak J., Bhagavatula R. & Kovačević J. 2010. ...
Three-dimensional simulations of earthquakes have given a deeper understanding of wave propagatio... more Three-dimensional simulations of earthquakes have given a deeper understanding of wave propagation and site effects in urban regions. Following on this interest, we study the impact of a potential major earthquake of significant seismic hazard on the San Andreas Fault. We present results for the Terashake 1.3 simulation---a rupture beginning near Bombay Beach, California heading 200 km north-west that produces
Proceedings of the 2006 ACM/IEEE conference on Supercomputing - SC '06, 2006
Parallel supercomputing has traditionally focused on the inner kernel of scientific simulations: ... more Parallel supercomputing has traditionally focused on the inner kernel of scientific simulations: the solver. The front and back ends of the simulation pipeline---problem description and interpretation of the output---have taken a back seat to the solver when it comes to attention paid to scalability and performance, and are often relegated to offline, sequential computation. As the largest simulations move beyond
Proceedings of the 1996 ACM/IEEE conference on Supercomputing (CDROM) - Supercomputing '96, 1996
Google, Inc. (search), Subscribe (Full Service), Register (Limited Service, Free), Login. Search:... more Google, Inc. (search), Subscribe (Full Service), Register (Limited Service, Free), Login. Search: The ACM Digital Library The Guide. ...
Proceedings of the 2006 ACM/IEEE conference on Supercomputing - SC '06, 2006
We have developed a novel analytic capability for scientists and engineers to obtain insight from... more We have developed a novel analytic capability for scientists and engineers to obtain insight from ongoing large-scale parallel unstructured mesh simulations running on thousands of processors. The breakthrough is made possible by a new approach that visualizes partial differential equation (PDE) solution data simultaneously while a parallel PDE solver executes. The solution field is pipelined directly to volume rendering, which is computed in parallel using the same processors that solve the PDE equations. Because our approach avoids the bottlenecks associated with transferring and storing large volumes of output data, it offers a promising approach to overcoming the challenges of visualization of petascale simulations. The submitted video demonstrates real-time on-the-fly monitoring, interpreting, and steering from a remote laptop computer of a 1024processor simulation of the 1994 Northridge earthquake in Southern California.
ACM/IEEE SC 2006 Conference (SC'06), 2006
Parallel supercomputing has traditionally focused on the inner kernel of scientific simulations: ... more Parallel supercomputing has traditionally focused on the inner kernel of scientific simulations: the solver. The front and back ends of the simulation pipeline-problem description and interpretation of the output-have taken a back seat to the solver when it comes to attention paid to scalability and performance, and are often relegated to offline, sequential computation. As the largest simulations move beyond the realm of the terascale and into the petascale, this decomposition in tasks and platforms becomes increasingly untenable. We propose an end-to-end approach in which all simulation components-meshing, partitioning, solver, and visualization-are tightly coupled and execute * IEEE in parallel with shared data structures and no intermediate I/O. We present our implementation of this new approach in the context of octree-based finite element simulation of earthquake ground motion. Performance evaluation on up to 2048 processors demonstrates the ability of the end-toend approach to overcome the scalability bottlenecks of the traditional approach.
2008 SC - International Conference for High Performance Computing, Networking, Storage and Analysis, 2008
Large-scale earthquake simulation requires source datasets which describe the highly heterogeneou... more Large-scale earthquake simulation requires source datasets which describe the highly heterogeneous physical characteristics of the earth in the region under simulation. Physical characteristic datasets are the first stage in a simulation pipeline which includes mesh generation, partitioning, solving, and visualization. In practice, the data is produced in an ad-hoc fashion for each set of experiments, which has several significant shortcomings including lower performance, decreased repeatability and comparability, and a longer time to science, an increasingly important metric.
Computational modeling has greatly contributed in recent years to the understanding of the effect... more Computational modeling has greatly contributed in recent years to the understanding of the effects of the source, wave propagation path, and site effects on earthquake ground motion in urban regions. Due in part to computational limitations and to limitations in the knowledge of the seismic velocities at the required scales, deterministic modeling of ground motion in realistic basins has been
Physics of the Earth and …, 2002
In this paper we report on the development and application of a parallel numerical methodology fo... more In this paper we report on the development and application of a parallel numerical methodology for simulating large-scale earthquake-induced ground motion in highly heterogeneous basins whose soil constituents can deform nonlinearly. We target ...
Physics of the Earth and Planetary Interiors, 2003
In this paper, we report on the development and application of a parallel numerical methodology f... more In this paper, we report on the development and application of a parallel numerical methodology for simulating large-scale earthquake-induced ground motion in highly heterogeneous basins whose soil constituents can deform nonlinearly. We target sedimentary basins with large contrasts in wavelengths for which regular grid methods become inefficient, and overcome the problem of multiple physical scales by using unstructured finite element
Advanced Modeling and Simulation in Engineering Sciences, 2015
Background: Recently the Double Absorbing Boundary (DAB) method was introduced as a new approach ... more Background: Recently the Double Absorbing Boundary (DAB) method was introduced as a new approach for solving wave problems in unbounded domains. It has common features to each of two types of existing techniques: local high-order Absorbing Boundary Conditions (ABC) and Perfectly Matched Layers (PML). However, it is different from both and enjoys relative advantages with respect to both.
Proceedings of the 2003 ACM/IEEE conference on Supercomputing - SC '03, 2003
Kwan-Liu Ma Aleksander Stompel Department of Computer Science University of California at Davis {... more Kwan-Liu Ma Aleksander Stompel Department of Computer Science University of California at Davis {ma,stompel}@cs.ucdavis.edu ... Jacobo Bielak Omar Ghattas Eui Joong Kim ... Computational Mechanics Laboratory, Department of Civil and Environmental Engineering Carnegie ...
We present a study of the ground motion and resulting amplification in the Mexico City Basin due ... more We present a study of the ground motion and resulting amplification in the Mexico City Basin due to strong earthquakes in the Mexican Pacific Coast. We propose an approximation of the regional structure and Mexico City's basin and analyze their response to two shallow earthquakes generated near the coast. We compare two sets of three dimensional simulations: the first includes
ABSTRACT We present a multiresolution classification framework with semi-supervised learning for ... more ABSTRACT We present a multiresolution classification framework with semi-supervised learning for the indirect structural health mon- itoring of bridges. The monitoring approach envisions a sens- ing system embedded into a moving vehicle traveling across the bridge of interest to measure the modal characteristics of the bridge. To enhance the reliability of the sensing system, we use a semi-supervised learning algorithm and a semi-su- pervised weighting algorithm within a multiresolution clas- sification framework. We show that the proposed algorithm performs significantly better than supervised multiresolution classification. Index
This paper presents a novel method for interpreting data to improve the indirect structural healt... more This paper presents a novel method for interpreting data to improve the indirect structural health monitoring (SHM) of bridges. The research presented in the study is part of an ongoing study aimed at developing a novel SHM paradigm for the health assessment of bridges. In this paradigm, we envision the use of an instrumented vehicle that assesses a bridge's dynamic characteristics while traveling across the bridge. These characteristics are then correlated to the health of the structure by means of advanced signal processing and pattern recognition approaches. In this paper, we present and compare two classification algorithms that locate the presence of damages at well-defined locations on the structure: sparse representation and the Fourier discriminant methods, and find that the sparse representation method provides superior classification accuracy.
We present a parallel octree-based finite el- ement method for large-scale earthquake ground moti... more We present a parallel octree-based finite el- ement method for large-scale earthquake ground motion simulation in realistic basins. The octree representa- tion combines the low memory per node and good cache performance of finite difference methods with the spa- tial adaptivity to local seismic wavelengths characteris- tic of unstructured finite element methods. Several tests are provided to verify the numerical
Bridge Maintenance, Safety and Management, 2012
... We are grateful for this support. We also thank Ranny Zhao and Colin Rutenbar, who participat... more ... We are grateful for this support. We also thank Ranny Zhao and Colin Rutenbar, who participated in the construction of the experimental setup. 8 REFERENCES Cerda F., Garrett J., Bielak J., Bhagavatula R. & Kovačević J. 2010. ...
Three-dimensional simulations of earthquakes have given a deeper understanding of wave propagatio... more Three-dimensional simulations of earthquakes have given a deeper understanding of wave propagation and site effects in urban regions. Following on this interest, we study the impact of a potential major earthquake of significant seismic hazard on the San Andreas Fault. We present results for the Terashake 1.3 simulation---a rupture beginning near Bombay Beach, California heading 200 km north-west that produces
Proceedings of the 2006 ACM/IEEE conference on Supercomputing - SC '06, 2006
Parallel supercomputing has traditionally focused on the inner kernel of scientific simulations: ... more Parallel supercomputing has traditionally focused on the inner kernel of scientific simulations: the solver. The front and back ends of the simulation pipeline---problem description and interpretation of the output---have taken a back seat to the solver when it comes to attention paid to scalability and performance, and are often relegated to offline, sequential computation. As the largest simulations move beyond
Proceedings of the 1996 ACM/IEEE conference on Supercomputing (CDROM) - Supercomputing '96, 1996
Google, Inc. (search), Subscribe (Full Service), Register (Limited Service, Free), Login. Search:... more Google, Inc. (search), Subscribe (Full Service), Register (Limited Service, Free), Login. Search: The ACM Digital Library The Guide. ...
Proceedings of the 2006 ACM/IEEE conference on Supercomputing - SC '06, 2006
We have developed a novel analytic capability for scientists and engineers to obtain insight from... more We have developed a novel analytic capability for scientists and engineers to obtain insight from ongoing large-scale parallel unstructured mesh simulations running on thousands of processors. The breakthrough is made possible by a new approach that visualizes partial differential equation (PDE) solution data simultaneously while a parallel PDE solver executes. The solution field is pipelined directly to volume rendering, which is computed in parallel using the same processors that solve the PDE equations. Because our approach avoids the bottlenecks associated with transferring and storing large volumes of output data, it offers a promising approach to overcoming the challenges of visualization of petascale simulations. The submitted video demonstrates real-time on-the-fly monitoring, interpreting, and steering from a remote laptop computer of a 1024processor simulation of the 1994 Northridge earthquake in Southern California.
ACM/IEEE SC 2006 Conference (SC'06), 2006
Parallel supercomputing has traditionally focused on the inner kernel of scientific simulations: ... more Parallel supercomputing has traditionally focused on the inner kernel of scientific simulations: the solver. The front and back ends of the simulation pipeline-problem description and interpretation of the output-have taken a back seat to the solver when it comes to attention paid to scalability and performance, and are often relegated to offline, sequential computation. As the largest simulations move beyond the realm of the terascale and into the petascale, this decomposition in tasks and platforms becomes increasingly untenable. We propose an end-to-end approach in which all simulation components-meshing, partitioning, solver, and visualization-are tightly coupled and execute * IEEE in parallel with shared data structures and no intermediate I/O. We present our implementation of this new approach in the context of octree-based finite element simulation of earthquake ground motion. Performance evaluation on up to 2048 processors demonstrates the ability of the end-toend approach to overcome the scalability bottlenecks of the traditional approach.
2008 SC - International Conference for High Performance Computing, Networking, Storage and Analysis, 2008
Large-scale earthquake simulation requires source datasets which describe the highly heterogeneou... more Large-scale earthquake simulation requires source datasets which describe the highly heterogeneous physical characteristics of the earth in the region under simulation. Physical characteristic datasets are the first stage in a simulation pipeline which includes mesh generation, partitioning, solving, and visualization. In practice, the data is produced in an ad-hoc fashion for each set of experiments, which has several significant shortcomings including lower performance, decreased repeatability and comparability, and a longer time to science, an increasingly important metric.
Computational modeling has greatly contributed in recent years to the understanding of the effect... more Computational modeling has greatly contributed in recent years to the understanding of the effects of the source, wave propagation path, and site effects on earthquake ground motion in urban regions. Due in part to computational limitations and to limitations in the knowledge of the seismic velocities at the required scales, deterministic modeling of ground motion in realistic basins has been
Physics of the Earth and …, 2002
In this paper we report on the development and application of a parallel numerical methodology fo... more In this paper we report on the development and application of a parallel numerical methodology for simulating large-scale earthquake-induced ground motion in highly heterogeneous basins whose soil constituents can deform nonlinearly. We target ...
Physics of the Earth and Planetary Interiors, 2003
In this paper, we report on the development and application of a parallel numerical methodology f... more In this paper, we report on the development and application of a parallel numerical methodology for simulating large-scale earthquake-induced ground motion in highly heterogeneous basins whose soil constituents can deform nonlinearly. We target sedimentary basins with large contrasts in wavelengths for which regular grid methods become inefficient, and overcome the problem of multiple physical scales by using unstructured finite element