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1,144 results on '"Fujita, Kohei"'

1. Heterogeneous computing in a strongly-connected CPU-GPU environment: fast multiple time-evolution equation-based modeling accelerated using data-driven approach

Author

Ichimura, Tsuyoshi, Fujita, Kohei, Hori, Muneo, Maddegedara, Lalith, Wells, Jack, Gray, Alan, Karlin, Ian, and Linford, John

Subjects
Computer Science - Computational Engineering, Finance, and Science
Abstract

We propose a CPU-GPU heterogeneous computing method for solving time-evolution partial differential equation problems many times with guaranteed accuracy, in short time-to-solution and low energy-to-solution. On a single-GH200 node, the proposed method improved the computation speed by 86.4 and 8.67 times compared to the conventional method run only on CPU and only on GPU, respectively. Furthermore, the energy-to-solution was reduced by 32.2-fold (from 9944 J to 309 J) and 7.01-fold (from 2163 J to 309 J) when compared to using only the CPU and GPU, respectively. Using the proposed method on the Alps supercomputer, a 51.6-fold and 6.98-fold speedup was attained when compared to using only the CPU and GPU, respectively, and a high weak scaling efficiency of 94.3% was obtained up to 1,920 compute nodes. These implementations were realized using directive-based parallel programming models while enabling portability, indicating that directives are highly effective in analyses in heterogeneous computing environments., Comment: 22 pages, 5 figures, accepted for Eleventh Workshop on Accelerator Programming and Directives (WACCPD 2024)

Published
2024

2. Development of an Estimation Method for the Seismic Motion Reproducibility of a Three-dimensional Ground Structure Model by combining Surface-observed Seismic Motion and Three-dimensional Seismic Motion Analysis

Author

Ichimura, Tsuyoshi, Fujita, Kohei, Kusakabe, Ryota, Fujiwara, Hiroyuki, Hori, Muneo, and Lalith, Maddegedara

Subjects
Computer Science - Computational Engineering, Finance, and Science
Abstract

The ground structure can substantially influence seismic ground motion underscoring the need to develop a ground structure model with sufficient reliability in terms of ground motion estimation for earthquake damage mitigation. While many methods for generating ground structure models have been proposed and used in practice, there remains room for enhancing their reliability. In this study, amid many candidate 3D ground structure models generated from geotechnical engineering knowledge, we propose a method for selecting a credible 3D ground structure model capable of reproducing observed earthquake ground motion, utilizing seismic ground motion data solely observed at the ground surface and employing 3D seismic ground motion analysis. Through a numerical experiment, we illustrate the efficacy of this approach. By conducting $10^2$-$10^3$ cases of fast 3D seismic wave propagation analyses using graphic processing units (GPUs), we demonstrate that a credible 3D ground structure model is selected according to the quantity of seismic motion information. We show the effectiveness of the proposed method by showing that the accuracy of seismic motions using ground structure models that were selected from the pool of candidate models is higher than that using ground structure models that were not selected from the pool of candidate models., Comment: 16 pages, 10 figures, accepted for IHPCES/ICCS 2024 (14th International Workshop on Advances in High-Performance Computational Earth Sciences: NumericalMethods, Frameworks & Applications / 24th International Conference on Computational Science)

Published
2024
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3. Low-ordered Orthogonal Voxel Finite Element with INT8 Tensor Cores for GPU-based Explicit Elastic Wave Propagation Analysis

Author

Ichimura, Tsuyoshi, Fujita, Kohei, Hori, Muneo, and Lalith, Maddegedara

Subjects
Computer Science - Distributed, Parallel, and Cluster Computing
Abstract

Faster explicit elastic wavefield simulations are required for large and complex three-dimensional media using a structured finite element method. Such wavefield simulations are suitable for GPUs, which have exhibited improved computational performance in recent years, and the use of GPUs is expected to speed up such simulations. However, available computational performance on GPUs is typically not fully exploited, and the conventional method involves some numerical dispersion. Thus, in this paper, we propose an explicit structured-mesh wavefield simulation method that uses INT8 Tensor Cores and reduces numerical dispersion to speed up computation on GPUs. The proposed method was implemented for GPUs, and its performance was evaluated in a simulation experiment of a real-world problem. The results demonstrate that the proposed method is 17.0 times faster than the conventional method., Comment: 16 pages, 6 figures, accepted for IHPCES/ICCS 2024 (14th International Workshop on Advances in High-Performance Computational Earth Sciences: Numerical Methods, Frameworks & Applications / 24th International Conference on Computational Science)

Published
2024
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16. Development of 3D Viscoelastic Crustal Deformation Analysis Solver with Data-Driven Method on GPU

Author

Murakami, Sota, Fujita, Kohei, Ichimura, Tsuyoshi, Hori, Takane, Hori, Muneo, Lalith, Maddegedara, Ueda, Naonori, Goos, Gerhard, Founding Editor, Hartmanis, Juris, Founding Editor, Bertino, Elisa, Editorial Board Member, Gao, Wen, Editorial Board Member, Steffen, Bernhard, Editorial Board Member, Yung, Moti, Editorial Board Member, Mikyška, Jiří, editor, de Mulatier, Clélia, editor, Paszynski, Maciej, editor, Krzhizhanovskaya, Valeria V., editor, Dongarra, Jack J., editor, and Sloot, Peter M.A., editor

Published
2023
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25. The DOLFIN method: a novel laparoscopic Billroth-I gastroduodenostomy for gastric cancer with duodenal invasion

Author

Shinno, Naoki, Omori, Takeshi, Hara, Hisashi, Yamamoto, Masaaki, Fujita, Kohei, Kanemura, Takashi, Takeoka, Tomohira, Sugase, Takahito, Yasui, Masayoshi, Matsuda, Chu, Wada, Hiroshi, Nishimura, Junichi, Haraguchi, Naotsugu, Akita, Hirofumi, Hasegawa, Shinichiro, Nakai, Nozomu, Asukai, Kei, Mukai, Yousuke, Miyata, Hiroshi, Ohue, Masayuki, and Sakon, Masato

Published
2022
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27. Calculation of Cross-correlation Function Accelerated by Tensor Cores with TensorFloat-32 Precision on Ampere GPU

Author

Kikuchi, Yuma, Fujita, Kohei, Ichimura, Tsuyoshi, Hori, Muneo, Maddegedara, Lalith, Goos, Gerhard, Founding Editor, Hartmanis, Juris, Founding Editor, Bertino, Elisa, Editorial Board Member, Gao, Wen, Editorial Board Member, Steffen, Bernhard, Editorial Board Member, Yung, Moti, Editorial Board Member, Groen, Derek, editor, de Mulatier, Clélia, editor, Paszynski, Maciej, editor, Krzhizhanovskaya, Valeria V., editor, Dongarra, Jack J., editor, and Sloot, Peter M. A., editor

Published
2022
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28. GPU Porting of Scalable Implicit Solver with Green’s Function-Based Neural Networks by OpenACC

Author

Fujita, Kohei, Kikuchi, Yuma, Ichimura, Tsuyoshi, Hori, Muneo, Maddegedara, Lalith, Ueda, Naonori, Goos, Gerhard, Founding Editor, Hartmanis, Juris, Founding Editor, Bertino, Elisa, Editorial Board Member, Gao, Wen, Editorial Board Member, Steffen, Bernhard, Editorial Board Member, Woeginger, Gerhard, Editorial Board Member, Yung, Moti, Editorial Board Member, Bhalachandra, Sridutt, editor, Daley, Christopher, editor, and Melesse Vergara, Verónica, editor

Published
2022
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29. Effectiveness and Safety of Atezolizumab Monotherapy in Previously Treated Japanese Patients With Unresectable Advanced or Recurrent NSCLC: A Multicenter, Prospective, Observational Study (J-TAIL)

Author

Miura, Satoru, Nishio, Makoto, Akamatsu, Hiroaki, Goto, Yasushi, Hayashi, Hidetoshi, Gemma, Akihiko, Yoshino, Ichiro, Misumi, Toshihiro, Hata, Akito, Hataji, Osamu, Fujita, Kohei, Seike, Masahiro, Yanagitani, Noriko, Nishino, Kazumi, Hara, Satoshi, Saito, Ryota, Mori, Masahide, Tsuda, Takeshi, Iwasawa, Shunichiro, Nakagawa, Shintaro, and Mitsudomi, Tetsuya

Published
2023
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32. Osimertinib and Bevacizumab Cotreatment for Untreated EGFR-Mutated NSCLC With Malignant Pleural or Pericardial Effusion (SPIRAL II): A Single-Arm, Open-Label, Phase 2 Clinical Trial

Author

Hibino, Makoto, Hiranuma, Osamu, Takemura, Yoshizumi, Katayama, Yuki, Chihara, Yusuke, Harada, Taishi, Fujita, Kohei, Kita, Toshiyuki, Tamiya, Nobuyo, Tsuda, Takeshi, Shiotsu, Shinsuke, Tamura, Yukihiro, Aoyama, Takashi, Nakamura, Yoichi, Terashima, Masaaki, Morimoto, Yoshie, Nagata, Kazuhiro, Yoshimura, Kenichi, Uchino, Junji, and Takayama, Koichi

Published
2022
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33. Clinical importance of carcinoembryonic antigen messenger RNA level in peritoneal lavage fluids measured by transcription-reverse transcription concerted reaction for advanced gastric cancer in laparoscopic surgery

Author

Fujita, Kohei, Omori, Takeshi, Hara, Hisashi, Shinno, Naoki, Yamamoto, Masaaki, Aoyama, Yoshimasa, Sugimura, Keijiro, Kanemura, Takashi, Takeoka, Tomohira, Yasui, Masayoshi, Matsuda, Chu, Takahashi, Hidenori, Wada, Hiroshi, Nishimura, Junichi, Haraguchi, Naotsugu, Hasegawa, Shinichiro, Nakai, Nozomu, Asukai, Kei, Mukai, Yosuke, Miyata, Hiroshi, Ohue, Masayuki, and Sakon, Masato

Published
2022
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38. Implicit Low-Order Unstructured Finite-Element Multiple Simulation Enhanced by Dense Computation using OpenACC

Author

Yamaguchi, Takuma, Fujita, Kohei, Ichimura, Tsuyoshi, Hori, Muneo, Lalith, Maddegedara, and Nakajima, Kengo

Subjects
Computer Science - Distributed, Parallel, and Cluster Computing, Computer Science - Mathematical Software
Abstract

In this paper, we develop a low-order three-dimensional finite-element solver for fast multiple-case crust deformation analysis on GPU-based systems. Based on a high-performance solver designed for massively parallel CPU based systems, we modify the algorithm to reduce random data access, and then insert OpenACC directives. The developed solver on ten Reedbush-H nodes (20 P100 GPUs) attained speedup of 14.2 times from 20 K computer nodes, which is high considering the peak memory bandwidth ratio of 11.4 between the two systems. On the newest Volta generation V100 GPUs, the solver attained a further 2.45 times speedup from P100 GPUs. As a demonstrative example, we computed 368 cases of crustal deformation analyses of northeast Japan with 400 million degrees of freedom. The total procedure of algorithm modification and porting implementation took only two weeks; we can see that high performance improvement was achieved with low development cost. With the developed solver, we can expect improvement in reliability of crust-deformation analyses by many-case analyses on a wide range of GPU-based systems., Comment: 18 pages, 10 figures, accepted for WACCPD2017

Published
2017

39. Large Scale Simulation of 3D Fault Rupture Subjected to Far‐Field Loading With PDS‐FEM: Application to the 2018 Palu Earthquake.

Author

Quaranta, Lionel, Maddegedara, Lalith, Kato, Aitaro, Hori, Muneo, Ichimura, Tsuyoshi, Fujita, Kohei, and Nicolin, Elia

Subjects
FRICTION, GROUND motion, MATHEMATICAL ability, EARTHQUAKES, CONDITIONED response, SURFACE fault ruptures
Abstract

Simulating dynamic rupture of fault systems can be computationally demanding, as it requires reproducing complex fault geometry and accurately capturing waves propagating away from the rupture front. It is in particular challenging to predict an initial stress state consistent with fault geometries, heterogeneous distribution of surrounding materials, and far‐field tectonic loading. While standard techniques such as contact analysis and Lagrangian multipliers can be used to model the fault, it can lead to significant computational overhead in FEM. We extended Particle Discretization Scheme‐FEM, which provides numerically efficient crack treatment, without requiring contact analysis, to simulate dynamic fault rupture as a frictional crack propagating along a pre‐existing shear crack surface. Initial stress, which is consistent with initial frictional forces, material distribution and fault geometry, is derived using Coulomb friction and far‐field boundary conditions. The study first demonstrates the ability of the numerical method to reproduce a 2D ideal supershear scenario, and the underlying Burridge‐Andrew rupture mechanism. The methodology is then applied to the large scale simulation of the 2018 Palu earthquake on the Palu‐Koro fault. The simulation successfully reproduces the early and sustained supershear rupture which was observed for the Palu earthquake. Also, it indicates that the presence of an off‐fault damage zone can contribute to the low rupture velocity measured during the earthquake. Unlike sub‐Rayleigh earthquakes, the shockwave propagation was observed to lead to significant amplitudes of the ground motion even far from the fault. Plain Language Summary: Earthquakes are generated from the frictional rupture of tectonic faults, which produces waves propagating through the ground. This rupture dynamic behavior is very dependent on the initial state of stress on the fault, which is influenced by many parameters, such as the fault geometry and tectonic loadings. For complex fault systems, with heterogeneous distribution of materials around the fault, calculating the fault stress state can be very computationally demanding with standard methods such as contact analysis. This paper uses a variant of the finite‐element method called Particle Discretization Scheme‐FEM, which provides an efficient crack treatment. The initial fault stress is generated from far‐field boundary conditions and is consistent with frictional forces, material distribution and the fault geometry. The proposed approach was applied to the study of supershear earthquakes, which occur when the rupture speed exceeds the shear wave velocity, inducing a shockwave. This work first demonstrates that the method successfully reproduces supershear rupture in simple 2D settings and then applies it to reproduce the 2018 Palu supershear earthquake. Our method recreates the early and sustained supershear rupture that was observed during the event, and shows the influence of initial fault stress and off‐fault damage on the rupture regime and velocity. Key Points: A new numerical approach based on PDS‐FEM is used to model 3D fault rupture subjected to far‐field loading for different rupture regimesInitial stress is set consistent with influencing factors such as complex fault geometry and heterogeneous frictional propertiesGround motion generated by supershear rupture decays slowly away from the fault and can be significantly impacted by fault geometry [ABSTRACT FROM AUTHOR]

Published
2024
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40. Large-Scale Stabilized Multi-physics Earthquake Simulation for Digital Twin

Author

Kusakabe, Ryota, Ichimura, Tsuyoshi, Fujita, Kohei, Hori, Muneo, Wijerathne, Lalith, Goos, Gerhard, Founding Editor, Hartmanis, Juris, Founding Editor, Bertino, Elisa, Editorial Board Member, Gao, Wen, Editorial Board Member, Steffen, Bernhard, Editorial Board Member, Woeginger, Gerhard, Editorial Board Member, Yung, Moti, Editorial Board Member, Paszynski, Maciej, editor, Kranzlmüller, Dieter, editor, Krzhizhanovskaya, Valeria V., editor, Dongarra, Jack J., editor, and Sloot, Peter M. A., editor

Published
2021
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41. Lower systolic blood pressure levels in early pregnancy are associated with a decreased risk of early-onset superimposed preeclampsia in women with chronic hypertension: a multicenter retrospective study

Author

Ueda, Akihiko, Hasegawa, Masaaki, Matsumura, Noriomi, Sato, Hiroshi, Kosaka, Kenzo, Abiko, Kaoru, Yoshioka, Shinya, Yoshida, Takaaki, Tatsumi, Keiji, Higuchi, Toshihiro, Fujita, Kohei, Sasaki, Shoko, Goto, Masaki, Takai, Hiroshi, Chigusa, Yoshitsugu, Mogami, Haruta, Sagawa, Norimasa, Mandai, Masaki, and Kondoh, Eiji

Published
2022
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43. Comparison of the Efficacy and Safety of Thoracoscopy under Local Anesthesia in Patients Aged over and under 75 Years: A Single-center Experience

Author

Fujita, Kohei, primary, Saito, Zentaro, additional, Ito, Takanori, additional, Yoden, Makoto, additional, Imakita, Takuma, additional, Oi, Issei, additional, Kaku, Ryosuke, additional, Yamamoto, Yuki, additional, Kanai, Osamu, additional, Tachibana, Hiromasa, additional, Sawai, Satoru, additional, and Mio, Tadashi, additional

Published
2024
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45. Data Assimilation in Volcano Deformation Using Fast Finite Element Analysis with High Fidelity Model

Author

Murakami, Sota, Yamaguchi, Takuma, Fujita, Kohei, Ichimura, Tsuyoshi, Lalith, Maddagedara, Hori, Muneo, Goos, Gerhard, Founding Editor, Hartmanis, Juris, Founding Editor, Bertino, Elisa, Editorial Board Member, Gao, Wen, Editorial Board Member, Steffen, Bernhard, Editorial Board Member, Woeginger, Gerhard, Editorial Board Member, Yung, Moti, Editorial Board Member, Krzhizhanovskaya, Valeria V., editor, Závodszky, Gábor, editor, Lees, Michael H., editor, Dongarra, Jack J., editor, Sloot, Peter M. A., editor, Brissos, Sérgio, editor, and Teixeira, João, editor

Published
2020
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46. Data-Driven Approach to Inversion Analysis of Three-Dimensional Inner Soil Structure via Wave Propagation Analysis

Author

Yamaguchi, Takuma, Ichimura, Tsuyoshi, Fujita, Kohei, Hori, Muneo, Wijerathne, Lalith, Ueda, Naonori, Goos, Gerhard, Founding Editor, Hartmanis, Juris, Founding Editor, Bertino, Elisa, Editorial Board Member, Gao, Wen, Editorial Board Member, Steffen, Bernhard, Editorial Board Member, Woeginger, Gerhard, Editorial Board Member, Yung, Moti, Editorial Board Member, Krzhizhanovskaya, Valeria V., editor, Závodszky, Gábor, editor, Lees, Michael H., editor, Dongarra, Jack J., editor, Sloot, Peter M. A., editor, Brissos, Sérgio, editor, and Teixeira, João, editor

Published
2020
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47. GPU Implementation of a Sophisticated Implicit Low-Order Finite Element Solver with FP21-32-64 Computation Using OpenACC

Author

Yamaguchi, Takuma, Fujita, Kohei, Ichimura, Tsuyoshi, Naruse, Akira, Lalith, Maddegedara, Hori, Muneo, Goos, Gerhard, Founding Editor, Hartmanis, Juris, Founding Editor, Bertino, Elisa, Editorial Board Member, Gao, Wen, Editorial Board Member, Steffen, Bernhard, Editorial Board Member, Woeginger, Gerhard, Editorial Board Member, Yung, Moti, Editorial Board Member, Wienke, Sandra, editor, and Bhalachandra, Sridutt, editor

Published
2020
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50. Heuristic Optimization with CPU-GPU Heterogeneous Wave Computing for Estimating Three-Dimensional Inner Structure

Author

Yamaguchi, Takuma, Ichimura, Tsuyoshi, Fujita, Kohei, Hori, Muneo, Wijerathne, Lalith, Hutchison, David, Editorial Board Member, Kanade, Takeo, Editorial Board Member, Kittler, Josef, Editorial Board Member, Kleinberg, Jon M., Editorial Board Member, Mattern, Friedemann, Editorial Board Member, Mitchell, John C., Editorial Board Member, Naor, Moni, Editorial Board Member, Pandu Rangan, C., Editorial Board Member, Steffen, Bernhard, Editorial Board Member, Terzopoulos, Demetri, Editorial Board Member, Tygar, Doug, Editorial Board Member, Goos, Gerhard, Founding Editor, Hartmanis, Juris, Founding Editor, Rodrigues, João M. F., editor, Cardoso, Pedro J. S., editor, Monteiro, Jânio, editor, Lam, Roberto, editor, Krzhizhanovskaya, Valeria V., editor, Lees, Michael H., editor, Dongarra, Jack J., editor, and Sloot, Peter M.A., editor

Published
2019
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