Kevin Bowers - Profile on Academia.edu (original) (raw)
Papers by Kevin Bowers
Cyclone-NTT: An NTT/FFT Architecture Using Quasi-Streaming of Large Datasets on DDR- and HBM-based FPGA Platforms
Proceedings of the 2023 ACM/SIGDA International Symposium on Field Programmable Gate Arrays
Script and Language Identification for Handwritten Document Images
A system for automatically identifying the script used in a handwritten document image is describ... more A system for automatically identifying the script used in a handwritten document image is described. The system was developed using a 496-document dataset representing six scripts, eight languages, and 281 writers. Documents were characterized by the mean, standard deviation, and skew of five connected component features. A linear discriminant analysis was used to classify new documents, and tested using writer-sensitive cross-validation. Classification accuracy averaged 88% across the six scripts. The same method, applied within the Roman subcorpus, discriminated English and German documents with 85% accuracy. Keywords: script, language, handwriting, discrimination, features 1. Introduction Script and language identification are important parts of the automatic processing of document images in an international environment. A document's script (e.g., Cyrillic or Roman) must be known in order to choose an appropriate optical character recognition (OCR) algorithm. For scripts use...
Dissipation and Spectral Energy Transfer in the Relaxation of 3-D Force-Free Magnetic Sheet Pinch
Three-dimensional fully kinetic Particle-in-Cell plasma simulations are used to study the magneti... more Three-dimensional fully kinetic Particle-in-Cell plasma simulations are used to study the magnetic reconnection in an initially force-free plasma with a sheet pinch configuration. The configuration drives unstable collisionless tearing modes at multiple resonant surfaces. The nonlinear ...
Handwritten Document Image Analysis at Los Alamos: Script, Language, and Writer Identification
A system for automatically identifying the script used in a handwritten document image is describ... more A system for automatically identifying the script used in a handwritten document image is described. The system was developed using a 496-document dataset representing six scripts, eight languages, and 281 writers. Documents were characterized by the mean, standard deviation, and skew of five connected component features. A linear discriminant analysis was used to classify new documents, and tested using writer-sensitive cross-validation. Classification accuracy averaged 88% across the six scripts. The same method, applied within the Roman subcorpus, discriminated English and German documents with 85% accuracy. Pilot results indicate that a variation of the method may be applicable to writer identification. 1. Introduction Script and language identification are important parts of the automatic processing of document images in an international environment. A document's script (e.g., Cyrillic or Roman) must be known in order to choose an appropriate optical character recognition ...
New Journal of Physics, 2013
Experimental data on laser-driven carbon C 6+ ion acceleration with a peak intensity of 5 × 10 20... more Experimental data on laser-driven carbon C 6+ ion acceleration with a peak intensity of 5 × 10 20 W cm −2 are presented and compared for opaque target normal sheath acceleration (TNSA) and relativistically transparent laser-plasma interactions. Particle numbers, peak ion energy and conversion efficiency have been investigated for target thicknesses from 50 nm to 25 µm using unprecedented full spectral beam profile line-out measurements made using a novel high-resolution ion wide-angle spectrometer. For thicknesses of about 200 nm, particle numbers and peak energy increase to 5 × 10 11 carbon C 6+ particles between 33 and 700 MeV (60 MeV u −1), which is a factor of five higher in particle number than that observed for targets with micron thickness. For 200 nm thick targets, we find that the peak conversion efficiency is 6% and that up to 55% of the target under the laser focal spot is accelerated to energies above 33 MeV. This contrasts with the results for targets with micron thickness, where surface acceleration with TNSA is dominant. The experimental findings are consistent with two-dimensional particle-in-cell simulations.
The Journal of Chemical Physics, 2007
Scalable Algorithms for Molecular Dynamics Simulations on Commodity Clusters
… , Proceedings of the …, 2007
Page 1. Although molecular dynamics (MD) simulations of biomolecular systems often run for days t... more Page 1. Although molecular dynamics (MD) simulations of biomolecular systems often run for days to months, many events of great scientific interest and pharmaceutical relevance occur on long time scales that remain beyond reach. ...
Particle in cell simulations of wave turbulence in solar wind in ion cyclotron frequency range
Fully electromagnetic particle in cell simulations of nonlinear waves propagation and interaction... more Fully electromagnetic particle in cell simulations of nonlinear waves propagation and interaction is performed in two-dimensional plane geometry in magnetized plasma in ion cyclotron frequency range. A spectrum of fast wave modes with different total energies with wave numbers parallel and perpendicular to uniform equilibrium magnetic field is launched into plasma and the nonlinear dynamics of these waves is analyzed.
***WITHDRAWN PATENT AS PER THE LATEST USPTO WITHDRAWN LIST***Approaches and architectures for computation of particle interactions
Kinetic Alfv�n waves and electron physics. I. Generation from ion-ion streaming
Phys Plasmas, 2007
Three-dimensional dynamics of breakout afterburner ion acceleration using high-contrast short-pulse laser and nanoscale targets
Physical review letters, Jan 22, 2011
Breakout afterburner (BOA) laser-ion acceleration has been demonstrated for the first time in the... more Breakout afterburner (BOA) laser-ion acceleration has been demonstrated for the first time in the laboratory. In the BOA, an initially solid-density target undergoes relativistically induced transparency, initiating a period of enhanced ion acceleration. First-ever kinetic simulations of the BOA in three dimensions show that the ion beam forms lobes in the direction orthogonal to laser polarization and propagation. Analytic theory presented for the electron dynamics in the laser ponderomotive field explains how azimuthal symmetry breaks even for a symmetric laser intensity profile; these results are consistent with recent experiments at the Trident laser facility.
Secondary Island Formation in Collisional and Collisionless Kinetic Simulations of Magnetic Reconnection
A Maximum Likelihood Method for Linking of Particle-in-Cell and Monte Carlo Simulations
To support the design and analysis of x-ray radiographic facilities and experiments at Los Alamos... more To support the design and analysis of x-ray radiographic facilities and experiments at Los Alamos, we have developed an integrated chain model, which is a set of linked physics simulation codes to generate self-consistent synthetic radiographs of experiments (1). The expectation-maximization (EM) algorithm (2) has recently been used to great advantage to link particle- in-cell (PIC) methods, which model electron
Script and language identification for handwritten document images
International Journal on Document Analysis and Recognition, 1999
Mechanism of Na+/H+ Antiporting
Science, 2007
Monoenergetic and GeV ion acceleration from the laser breakout afterburner using ultrathin targets
Physics of Plasmas, 2007
Kinetic Alfvén waves and electron physics. I. Generation from ion-ion streaming
Physics of Plasmas, 2007
Theory of Laser Acceleration of Light-Ion Beams from Interaction of Ultrahigh-Intensity Lasers with Layered Targets
Physical Review Letters, 2006
Enhanced Laser-Driven Ion Acceleration in the Relativistic Transparency Regime
Physical Review Letters, 2009
Three-Dimensional Dynamics of Collisionless Magnetic Reconnection in Large-Scale Pair Plasmas
Physical Review Letters, 2008
Cyclone-NTT: An NTT/FFT Architecture Using Quasi-Streaming of Large Datasets on DDR- and HBM-based FPGA Platforms
Proceedings of the 2023 ACM/SIGDA International Symposium on Field Programmable Gate Arrays
Script and Language Identification for Handwritten Document Images
A system for automatically identifying the script used in a handwritten document image is describ... more A system for automatically identifying the script used in a handwritten document image is described. The system was developed using a 496-document dataset representing six scripts, eight languages, and 281 writers. Documents were characterized by the mean, standard deviation, and skew of five connected component features. A linear discriminant analysis was used to classify new documents, and tested using writer-sensitive cross-validation. Classification accuracy averaged 88% across the six scripts. The same method, applied within the Roman subcorpus, discriminated English and German documents with 85% accuracy. Keywords: script, language, handwriting, discrimination, features 1. Introduction Script and language identification are important parts of the automatic processing of document images in an international environment. A document's script (e.g., Cyrillic or Roman) must be known in order to choose an appropriate optical character recognition (OCR) algorithm. For scripts use...
Dissipation and Spectral Energy Transfer in the Relaxation of 3-D Force-Free Magnetic Sheet Pinch
Three-dimensional fully kinetic Particle-in-Cell plasma simulations are used to study the magneti... more Three-dimensional fully kinetic Particle-in-Cell plasma simulations are used to study the magnetic reconnection in an initially force-free plasma with a sheet pinch configuration. The configuration drives unstable collisionless tearing modes at multiple resonant surfaces. The nonlinear ...
Handwritten Document Image Analysis at Los Alamos: Script, Language, and Writer Identification
A system for automatically identifying the script used in a handwritten document image is describ... more A system for automatically identifying the script used in a handwritten document image is described. The system was developed using a 496-document dataset representing six scripts, eight languages, and 281 writers. Documents were characterized by the mean, standard deviation, and skew of five connected component features. A linear discriminant analysis was used to classify new documents, and tested using writer-sensitive cross-validation. Classification accuracy averaged 88% across the six scripts. The same method, applied within the Roman subcorpus, discriminated English and German documents with 85% accuracy. Pilot results indicate that a variation of the method may be applicable to writer identification. 1. Introduction Script and language identification are important parts of the automatic processing of document images in an international environment. A document's script (e.g., Cyrillic or Roman) must be known in order to choose an appropriate optical character recognition ...
New Journal of Physics, 2013
Experimental data on laser-driven carbon C 6+ ion acceleration with a peak intensity of 5 × 10 20... more Experimental data on laser-driven carbon C 6+ ion acceleration with a peak intensity of 5 × 10 20 W cm −2 are presented and compared for opaque target normal sheath acceleration (TNSA) and relativistically transparent laser-plasma interactions. Particle numbers, peak ion energy and conversion efficiency have been investigated for target thicknesses from 50 nm to 25 µm using unprecedented full spectral beam profile line-out measurements made using a novel high-resolution ion wide-angle spectrometer. For thicknesses of about 200 nm, particle numbers and peak energy increase to 5 × 10 11 carbon C 6+ particles between 33 and 700 MeV (60 MeV u −1), which is a factor of five higher in particle number than that observed for targets with micron thickness. For 200 nm thick targets, we find that the peak conversion efficiency is 6% and that up to 55% of the target under the laser focal spot is accelerated to energies above 33 MeV. This contrasts with the results for targets with micron thickness, where surface acceleration with TNSA is dominant. The experimental findings are consistent with two-dimensional particle-in-cell simulations.
The Journal of Chemical Physics, 2007
Scalable Algorithms for Molecular Dynamics Simulations on Commodity Clusters
… , Proceedings of the …, 2007
Page 1. Although molecular dynamics (MD) simulations of biomolecular systems often run for days t... more Page 1. Although molecular dynamics (MD) simulations of biomolecular systems often run for days to months, many events of great scientific interest and pharmaceutical relevance occur on long time scales that remain beyond reach. ...
Particle in cell simulations of wave turbulence in solar wind in ion cyclotron frequency range
Fully electromagnetic particle in cell simulations of nonlinear waves propagation and interaction... more Fully electromagnetic particle in cell simulations of nonlinear waves propagation and interaction is performed in two-dimensional plane geometry in magnetized plasma in ion cyclotron frequency range. A spectrum of fast wave modes with different total energies with wave numbers parallel and perpendicular to uniform equilibrium magnetic field is launched into plasma and the nonlinear dynamics of these waves is analyzed.
***WITHDRAWN PATENT AS PER THE LATEST USPTO WITHDRAWN LIST***Approaches and architectures for computation of particle interactions
Kinetic Alfv�n waves and electron physics. I. Generation from ion-ion streaming
Phys Plasmas, 2007
Three-dimensional dynamics of breakout afterburner ion acceleration using high-contrast short-pulse laser and nanoscale targets
Physical review letters, Jan 22, 2011
Breakout afterburner (BOA) laser-ion acceleration has been demonstrated for the first time in the... more Breakout afterburner (BOA) laser-ion acceleration has been demonstrated for the first time in the laboratory. In the BOA, an initially solid-density target undergoes relativistically induced transparency, initiating a period of enhanced ion acceleration. First-ever kinetic simulations of the BOA in three dimensions show that the ion beam forms lobes in the direction orthogonal to laser polarization and propagation. Analytic theory presented for the electron dynamics in the laser ponderomotive field explains how azimuthal symmetry breaks even for a symmetric laser intensity profile; these results are consistent with recent experiments at the Trident laser facility.
Secondary Island Formation in Collisional and Collisionless Kinetic Simulations of Magnetic Reconnection
A Maximum Likelihood Method for Linking of Particle-in-Cell and Monte Carlo Simulations
To support the design and analysis of x-ray radiographic facilities and experiments at Los Alamos... more To support the design and analysis of x-ray radiographic facilities and experiments at Los Alamos, we have developed an integrated chain model, which is a set of linked physics simulation codes to generate self-consistent synthetic radiographs of experiments (1). The expectation-maximization (EM) algorithm (2) has recently been used to great advantage to link particle- in-cell (PIC) methods, which model electron
Script and language identification for handwritten document images
International Journal on Document Analysis and Recognition, 1999
Mechanism of Na+/H+ Antiporting
Science, 2007
Monoenergetic and GeV ion acceleration from the laser breakout afterburner using ultrathin targets
Physics of Plasmas, 2007
Kinetic Alfvén waves and electron physics. I. Generation from ion-ion streaming
Physics of Plasmas, 2007
Theory of Laser Acceleration of Light-Ion Beams from Interaction of Ultrahigh-Intensity Lasers with Layered Targets
Physical Review Letters, 2006
Enhanced Laser-Driven Ion Acceleration in the Relativistic Transparency Regime
Physical Review Letters, 2009
Three-Dimensional Dynamics of Collisionless Magnetic Reconnection in Large-Scale Pair Plasmas
Physical Review Letters, 2008