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Hashimoto, Shoji*; Tanaka, Taku*; Komatsu, Masabumi*; Gonze, M.-A.*; Sakashita, Wataru*; Kurikami, Hiroshi; Nishina, Kazuya*; Ota, Masakazu; Ohashi, Shinta*; Calmon, P.*; et al.
Journal of Environmental Radioactivity, 238-239, p.106721_1 - 106721_10, 2021/11
Times Cited Count：12 Percentile：56.00(Environmental Sciences)This study was aimed at analysing performance of models for radiocesium migration mainly in evergreen coniferous forest in Fukushima, by inter-comparison between models of several research teams. The exercise included two scenarios of countermeasures against the contamination, namely removal of soil surface litter and forest renewal, and a specific konara oak forest scenario in addition to the evergreen forest scenario. All the models reproduced trend of time evolution of radiocesium inventories and concentrations in each of the components in forest such as leaf and organic soil layer. However, the variations between models enlarged in long-term predictions over 50 years after the fallout, meaning continuous field monitoring and model verification/validation is necessary.
Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Takagi, Yasuhiko*; Nakamura, Tomoki*; Hiroi, Takahiro*; Matsuoka, Moe*; et al.
Nature Astronomy (Internet), 5(3), p.246 - 250, 2021/03
Times Cited Count：51 Percentile：96.49(Astronomy & Astrophysics)Here we report observations of Ryugu's subsurface material by the Near-Infrared Spectrometer (NIRS3) on the Hayabusa2 spacecraft. Reflectance spectra of excavated material exhibit a hydroxyl (OH) absorption feature that is slightly stronger and peak-shifted compared with that observed for the surface, indicating that space weathering and/or radiative heating have caused subtle spectral changes in the uppermost surface. However, the strength and shape of the OH feature still suggests that the subsurface material experienced heating above 300 
C, similar to the surface. In contrast, thermophysical modeling indicates that radiative heating does not increase the temperature above 200 C at the estimated excavation depth of 1 m, even if the semimajor axis is reduced to 0.344 au. This supports the hypothesis that primary thermal alteration occurred due to radiogenic and/or impact heating on Ryugu's parent body.
Zhou, W.*; Seki, Takeshi*; Imamura, Hiroshi*; Ieda, Junichi; Takanashi, Koki*
Physical Review B, 100(9), p.094424_1 - 094424_5, 2019/09
Times Cited Count：7 Percentile：33.40(Materials Science, Multidisciplinary)Kawamura, Takuma; Idomura, Yasuhiro; Miyamura, Hiroko; Imamura, Toshiyuki*; Takemiya, Hiroshi
Shisutemu Seigyo Joho Gakkai Rombunshi, 28(5), p.221 - 227, 2015/05
However remote volume visualization is important to obtain knowledge from complicated large-scale simulation results on supercomputer, the rendering speed and data transfer speed becomes bottleneck of the conventional Client/Server volume visualization techniques. Client/Server visualization system using particle-based volume rendering enables interactive volume visualization, which converts the original volume data to small size light particle data utilizing the supercomputer and transfer the data to Client PC. This system generated the particle data at a few seconds using parallel process on supercomputer Kei with strong scaling till 1000 processers.
Ichimura, Masahiko*; Hamada, Tomoyuki*; Imamura, Hiroshi*; Takahashi, Saburo*; Maekawa, Sadamichi
Journal of Applied Physics, 109(7), p.07C906_1 - 07C906_3, 2011/03
Times Cited Count：5 Percentile：22.82(Physics, Applied)Imamura, Toshiyuki; Hasegawa, Yukihiro*; Yamagishi, Nobuhiro*; Takemiya, Hiroshi*
Keisan Kogaku Koenkai Rombunshu, 8(2), p.793 - 796, 2003/05
no abstracts in English
Imamura, Toshiyuki*; Yamagishi, Nobuhiro*; Takemiya, Hiroshi*; Hasegawa, Yukihiro*; Higuchi, Kenji; Nakajima, Norihiro
Lecture Notes in Computer Science 2858, p.258 - 268, 2003/00
no abstracts in English
Tsujita, Yuichi*; Imamura, Toshiyuki*; Yamagishi, Nobuhiro*; Takemiya, Hiroshi*
Parallel and Distributed Processing and Applications (International Symposium, ISPA 2003), p.139 - 144, 2003/00
An MPI library for heterogeneous computing environment, Stampi, has been implemented on an SCore cluster system to enable dynamic process creation defined in MPI-2 and MPI communication among multiple clusters. Objective of this implementation is realization of heterogeneous computing environment with an SCore PC cluster and other machines. Through performance measurement, sufficient performance has been achieved and effectiveness of our flexible implementation has been confirmed.
Tsujita, Yuichi; Imamura, Toshiyuki; Takemiya, Hiroshi*; Yamagishi, Nobuhiro*
Keisan Kogaku Koenkai Rombunshu, 7(1), p.159 - 162, 2002/05
no abstracts in English
Imamura, Toshiyuki; Hasegawa, Yukihiro*; Yamagishi, Nobuhiro*; Takemiya, Hiroshi*
Recent Advances in Computational Science & Engineering, p.789 - 792, 2002/00
no abstracts in English
Tsujita, Yuichi; Imamura, Toshiyuki; Takemiya, Hiroshi*; Yamagishi, Nobuhiro*
Recent Advances in Parallel Virtual Machine and Message Passing Interface, p.288 - 295, 2002/00
An MPI-2 based parallel-I/O library, Stampi-I/O, has been developed using flexible communication infrastructure. In Stampi-I/O almost all MPI-I/O functions have been implemented. We can execute these functions using both local and remote I/O operations with the same application program interface (API) based on MPI-2. In I/O operations using Stampi-I/O, users need not handle any differences in the communication mechanism of computers. We have evaluated performance for primitive functions in Stampi-I/O. Through this test, sufficient performance has been achieved and effectiveness of our flexible implementation has been confirmed.
Tanaka, Susumu; Nakashima, Hiroshi; Sakamoto, Yukio; Nakane, Yoshihiro; Meigo, Shinichiro; Tanaka, Shunichi; Nakamura, Takashi*; Takada, Masashi*; Kurosawa, Tadahiro*; Hirayama, Hideo*; et al.
Health Physics, 81(4), p.406 - 418, 2001/10
Times Cited Count：5 Percentile：38.55(Environmental Sciences)no abstracts in English
Tsujita, Yuichi; Imamura, Toshiyuki; Takemiya, Hiroshi*; Yamagishi, Nobuhiro*
Proceedings of 5th World Multiconference on Systemics, Cybernetics and Informatics (SCI 2001), p.402 - 407, 2001/07
An MPI-2 based distributed parallel-I/O library called Stampi-I/O has been developed using communication infrastructure of Stampi. Stampi is a communication library based on MPI and MPI-2. It has been developed for heterogeneous computing environment as infrastructure of metacomputing. As many applications in computational science handle huge amount of data which one parallel computer can not handle, distributed parallel-I/O libraries have been required for effective handling of such huge data on heterogeneous computing environment. Considering this situation, Stampi-I/O has been designed and developed. In this paper, motivations, architecture and preliminary results of performance measurement of Stampi-I/O are described.
Muramatsu, Kazuhiro; Imamura, Toshiyuki; Kitabata, Hideyuki; Kaneko, Isamu; Takemiya, Hiroshi*; Hasegawa, Yukihiro*; Yamagishi, Nobuhiro*; Hirayama, Toshio
Keisan Kogaku Koenkai Rombunshu, 6(1), p.241 - 244, 2001/05
no abstracts in English
Imamura, Toshiyuki; Muramatsu, Kazuhiro; Kitabata, Hideyuki*; Kaneko, Isamu*; Yamagishi, Nobuhiro*; Hasegawa, Yukihiro*; Takemiya, Hiroshi*; Hirayama, Toshio
Joho Shori Gakkai Kenkyu Hokoku 2001-ARC-142, p.49 - 54, 2001/03
no abstracts in English
Mochizuki, Yuji*; Koide, Hiroshi; Imamura, Toshiyuki; Takemiya, Hiroshi*
Journal of Synchrotron Radiation, 8(Part.2), p.1003 - 1005, 2001/03
no abstracts in English
Tsujita, Yuichi; Imamura, Toshiyuki; Takemiya, Hiroshi*; Yamagishi, Nobuhiro*
Joho Shori Gakkai Kenkyu Hokoku 2000-HPC-84, p.43 - 48, 2000/12
no abstracts in English
Takemiya, Hiroshi*; Imamura, Toshiyuki; Koide, Hiroshi; Higuchi, Kenji; Tsujita, Yuichi; Yamagishi, Nobuhiro*; Matsuda, Katsuyuki*; Ueno, Koichi*; Hasegawa, Yukihiro*; Kimura, Toshiya; et al.
Proceedings of 4th International Conference on Supercomputing in Nuclear Applications (SNA 2000) (CD-ROM), 16 Pages, 2000/09
no abstracts in English
Ueno, Koichi*; Ota, Hirofumi*; Takemiya, Hiroshi*; Imamura, Toshiyuki; Koide, Hiroshi; Matsuda, Katsuyuki*; Higuchi, Kenji; Hirayama, Toshio
JAERI-Data/Code 2000-023, p.287 - 0, 2000/03
JAERI-Data-Code-2000-023.pdf:34.96MB
no abstracts in English
Takemiya, Hiroshi*; Yamagishi, Nobuhiro*; Imamura, Toshiyuki; Ueno, Koichi*; Koide, Hiroshi; Tsujita, Yuichi; Hasegawa, Yukihiro*; Higuchi, Kenji; Matsuda, Katsuyuki*; Hirayama, Toshio
JAERI-Data/Code 2000-013, p.52 - 0, 2000/03
JAERI-Data-Code-2000-013.pdf:8.64MB
no abstracts in English
