The First Star-by-star $N$-body/Hydrodynamics Simulation of Our Galaxy Coupling with a Surrogate Model.

Takashi Okamoto Keiya Hirashima Michiko S. Fujii Takayuki R. Saitoh Naoto Harada Kentaro Nomura Kohji Yoshikawa Yutaka Hirai Tetsuro Asano Kana Moriwaki Masaki Iwasawa Takashi Okamoto Junichiro Makino The First Star-by-star $N$-body/Hydrodynamics Simulation of Our Galaxy Coupling with a Surrogate Model. 1859-1873 2025 SC https://doi.org/10.1145/3712285.3759866 conf/sc/2025 db/conf/sc/sc2025.html#HirashimaFSHNYH25

Keiya Hirashima Michiko S. Fujii Takayuki R. Saitoh Naoto Harada Kentaro Nomura Kohji Yoshikawa Yutaka Hirai Tetsuro Asano Kana Moriwaki Masaki Iwasawa Takashi Okamoto Junichiro Makino The First Star-by-star N-body/Hydrodynamics Simulation of Our Galaxy Coupling with a Surrogate Model. 2025 October abs/2510.23330 CoRR https://doi.org/10.48550/arXiv.2510.23330 db/journals/corr/corr2510.html#abs-2510-23330 streams/journals/corr

Yohei Hosoe Takashi Okamoto Tomomichi Hagiwara H₂ Performance Analysis and Synthesis for Discrete-Time Linear Systems With Dynamics Determined by an i.i.d. Process. 751-756 2023 7 IEEE Control. Syst. Lett. https://doi.org/10.1109/LCSYS.2022.3224875 db/journals/csysl/csysl7.html#HosoeOH23

Yohei Hosoe Takashi Okamoto Tomomichi Hagiwara H2 Performance Analysis and Synthesis for Discrete-Time Linear Systems with Dynamics Determined by an i.i.d. Process. 2022 abs/2209.03606 CoRR https://doi.org/10.48550/arXiv.2209.03606 db/journals/corr/corr2209.html#abs-2209-03606

Takashi Okamoto Determinants of Purchase Intention in Online Purchasing During the COVID-19 Pandemic in Japan. 32-37 2021 MISNC https://doi.org/10.1145/3504006.3504012 conf/misnc/2021 db/conf/misnc/misnc2021.html#Okamoto21 Takashi Okamoto Jiro Yatsuhashi Naoki Mizutani Consumers' Priorities for Online Flea Market. 6:1-6:6 2020 MISNC/IEMT https://doi.org/10.1145/3429395.3429400 conf/misnc/2020 db/conf/misnc/misnc2020.html#OkamotoYM20 Takashi Ohnishi Takashi Okamoto Keiichi Watanuki Effect of Magnet Shapes on Metal Contamination Removal. 428-437 2019 CATA https://doi.org/10.29007/9pvg conf/cata/2019 db/conf/cata/cata2019.html#OhnishiOW19 Takashi Okamoto Jiro Yatsuhashi Naoki Mizutani Japanese University Students' Acceptance of Cross-border Electronic Commerce. 106-117 2019 MISNC https://doi.org/10.1007/978-981-15-1758-7_9 conf/misnc/2019 db/conf/misnc/misnc2019.html#OkamotoYM19 Takashi Okamoto Jiro Yatsuhashi Naoki Mizutani Young People's Purchase Intentions in Online Flea Market. 7:1-7:6 2018 MISNC https://doi.org/10.1145/3227696.3227704 conf/misnc/2018 db/conf/misnc/misnc2018.html#OkamotoYM18

Takashi Okamoto Nobuyuki Soga Taro Kumagai Hideo Arai The Perceptual Gaps Between Companies' and University Students' Views on Fundamental Competencies. 143-157 2017 11 Rev. Socionetwork Strateg. 2 https://doi.org/10.1007/s12626-017-0008-z db/journals/rss/rss11.html#OkamotoSKA17

Takashi Okamoto Different perceptions of online shopping concerning product availability, consumer location, and experience. 233-258 2016 11 Int. J. Web Eng. Technol. 3 https://doi.org/10.1504/IJWET.2016.079038 db/journals/ijwet/ijwet11.html#Okamoto16

Naoto Suzuki Takashi Okamoto Seiichi Koakutsu A Pareto Optimal Solution Visualization Method Using an Improved Growing Hierarchical Self-Organizing Maps Based on the Batch Learning. 691-704 2016 20 J. Adv. Comput. Intell. Intell. Informatics 5 https://doi.org/10.20965/jaciii.2016.p0691 db/journals/jaciii/jaciii20.html#SuzukiOK16

Takashi Okamoto Nobuyuki Soga Taro Kumagai Hideo Arai Realities and Ideals of Competencies: The Perceptual Gaps between Companies and University Students. 18 2016 MISNC https://doi.org/10.1145/2955129.2955134 conf/misnc/2016 db/conf/misnc/misnc2016.html#OkamotoSKA16 Yusuke Kobayashi Takashi Okamoto Seiichi Koakutsu A Pareto optimal solution visualization method using SOM-NG with learning parameter optimization. 4525-4531 2016 SMC https://doi.org/10.1109/SMC.2016.7844944 conf/smc/2016 db/conf/smc/smc2016.html#KobayashiOK16 Naoto Suzuki Takashi Okamoto Seiichi Koakutsu Visualization of Pareto optimal solutions using MIGSOM. 2556-2564 2015 CEC https://doi.org/10.1109/CEC.2015.7257203 conf/cec/2015 db/conf/cec/cec2015.html#SuzukiOK15 Koichi Yoshida Takashi Okamoto Seiichi Koakutsu Equilibrium Solution Search on a Selfish Routing Problem with Multiple Constraints Using the Variable Metric Gradient Projection Method. 3023-3029 2015 SMC https://doi.org/10.1109/SMC.2015.526 conf/smc/2015 db/conf/smc/smc2015.html#YoshidaOK15 Takashi Okamoto Consumer Priorities in Online Shopping. 386-396 2014 KMO https://doi.org/10.1007/978-3-319-08618-7_37 conf/kmo/2014 db/conf/kmo/kmo2014.html#Okamoto14 Takashi Okamoto Constrained optimization using the chaotic sequential quadratic approximation type Lagrange quasi-Newton method. 562-568 2014 SMC https://doi.org/10.1109/SMC.2014.6973967 conf/smc/2014 db/conf/smc/smc2014.html#Okamoto14

Takashi Okamoto Hironori Hirata Global optimization using a multipoint type quasi-chaotic optimization method. 1247-1264 2013 13 Appl. Soft Comput. 2 https://doi.org/10.1016/j.asoc.2012.10.025 db/journals/asc/asc13.html#OkamotoH13

Takashi Okamoto Japanese Students' Perception of B2C. 451-462 2013 KMO https://doi.org/10.1007/978-94-007-7287-8_36 conf/kmo/2013 db/conf/kmo/kmo2013.html#Okamoto13 Takashi Okamoto Eitaro Aiyoshi Gamification of the Optimization Problem and Multi-point Type Optimization Methods. 3516-3522 2013 SMC https://doi.org/10.1109/SMC.2013.600 conf/smc/2013 db/conf/smc/smc2013.html#OkamotoA13 Takashi Okamoto Hironori Hirata Chaotic Optimization Method without Initial Sampling Parameter Tuning - Empirical Comparisons of Two Approaches in Various Problems. 3529-3536 2013 SMC https://doi.org/10.1109/SMC.2013.602 conf/smc/2013 db/conf/smc/smc2013.html#OkamotoH13

Eitaro Aiyoshi Atsushi Maki Takashi Okamoto The robustness of a Nash equilibrium simulation model: Game-theoretic approach using variable metric projection method. 1518-1526 2011 81 Math. Comput. Simul. 7 https://doi.org/10.1016/j.matcom.2010.06.002 db/journals/mcs/mcs81.html#AiyoshiMO11

Nobuyuki Soga Takashi Okamoto Using Choice Experiments to Value an Electronic Commerce. 568-573 2011 SAINT https://doi.org/10.1109/SAINT.2011.105 https://doi.ieeecomputersociety.org/10.1109/SAINT.2011.105 conf/saint/2011 db/conf/saint/saint2011.html#SogaO11 Takashi Okamoto Hironori Hirata Constrained optimization using the quasi-chaotic optimization method with the exact penalty function and the sequential quadratic programming. 1765-1770 2011 SMC https://doi.org/10.1109/ICSMC.2011.6083927 conf/smc/2011 db/conf/smc/smc2011.html#OkamotoH11 Takashi Okamoto The Study on Consumer Behavior of Online Shops. 320-323 2010 SAINT https://doi.org/10.1109/SAINT.2010.36 https://doi.ieeecomputersociety.org/10.1109/SAINT.2010.36 conf/saint/2010 db/conf/saint/saint2010.html#Okamoto10 Takashi Okamoto Hironori Hirata Global optimization using a multi-point type quasi-chaotic optimization method with the simultaneous perturbation gradient approximation. 804-809 2010 SMC https://doi.org/10.1109/ICSMC.2010.5641854 conf/smc/2010 db/conf/smc/smc2010.html#OkamotoH10 Takashi Okamoto Information Sharing System for Maintenance of Sewage Facilities. 212-215 2009 SAINT https://doi.org/10.1109/SAINT.2009.48 https://doi.ieeecomputersociety.org/10.1109/SAINT.2009.48 conf/saint/2009 db/conf/saint/saint2009.html#Okamoto09 Takashi Okamoto Hironori Hirata Constrained Optimization using the Lagrangian Method and the Improved Discrete Gradient Chaos Model. 3909-3916 2009 SMC conf/smc/2009 db/conf/smc/smc2009.html#OkamotoH09 https://doi.org/10.1109/ICSMC.2009.5346658

Takashi Okamoto Eitaro Aiyoshi Global optimization using a synchronization of multiple search Points autonomously driven by a chaotic dynamic model. 219-244 2008 41 J. Glob. Optim. 2 https://doi.org/10.1007/s10898-007-9222-5 db/journals/jgo/jgo41.html#OkamotoA08

Takashi Okamoto Kyle Buza Visualization of Social Interactions in Facebook. 2008 ICWSM http://www.aaai.org/Library/ICWSM/2008/icwsm08-058.php conf/icwsm/2008 db/conf/icwsm/icwsm2008.html#OkamotoB08 Takashi Okamoto B to C for Revitalizing Rural Economy. 425-428 2008 SAINT https://doi.org/10.1109/SAINT.2008.78 https://doi.ieeecomputersociety.org/10.1109/SAINT.2008.78 conf/saint/2008 db/conf/saint/saint2008.html#Okamoto08 Yoichi Takeuchi Takashi Okamoto Kazutoshi Yokoyama Shigeyuki Matsuda A Differential-analysis Approach for Improving SOAP Processing Performance. 472-479 2005 conf/eee/2005 EEE https://doi.org/10.1109/EEE.2005.5 https://doi.ieeecomputersociety.org/10.1109/EEE.2005.5 db/conf/eee/eee2005.html#TakeuchiOYM05

Kazufumi Kaneda Takashi Okamoto Eihachiro Nakamae Tomoyuki Nishita Photorealistic image synthesis for outdoor scenery under various atmospheric conditions. 247-258 1991 7 Vis. Comput. 5&6 db/journals/vc/vc7.html#KanedaONN91 https://doi.org/10.1007/BF01905690

Eihachiro Nakamae Kazufumi Kaneda Takashi Okamoto Tomoyuki Nishita A lighting model aiming at drive simulators. 395-404 1990 conf/siggraph/1990 SIGGRAPH https://doi.org/10.1145/97879.97922 https://www.wikidata.org/entity/Q60895172 db/conf/siggraph/siggraph1990.html#NakamaeKON90 Eitaro Aiyoshi Hideo Arai Tetsuro Asano Kyle Buza Michiko S. Fujii Tomomichi Hagiwara Naoto Harada Yutaka Hirai Keiya Hirashima Hironori Hirata Yohei Hosoe Masaki Iwasawa Kazufumi Kaneda Seiichi Koakutsu Yusuke Kobayashi Taro Kumagai Atsushi Maki Junichiro Makino Shigeyuki Matsuda Naoki Mizutani Kana Moriwaki Eihachiro Nakamae Tomoyuki Nishita Kentaro Nomura Takashi Ohnishi Takayuki R. Saitoh Nobuyuki Soga Naoto Suzuki Yoichi Takeuchi Keiichi Watanuki Jiro Yatsuhashi Kazutoshi Yokoyama Koichi Yoshida Kohji Yoshikawa