Search

Your search keyword '"Matsuda, Koji"' showing total 440 results
Start Over Author "Matsuda, Koji"
440 results on '"Matsuda, Koji"'

2. Rational points on Shimura varieties classifying abelian varieties with quaternionic multiplication

Author

Matsuda, Koji

Subjects
Mathematics - Number Theory
Abstract

We study the characters induced by suitable level structures of abelian varieties with quaternionic multiplication following the methods of Mazur, Momose, who studied the characters induced by elliptic curves, and Arai--Momose, who studied the characters induced by abelian surfaces with quaternionic multiplication. Also using results on such characters we show that Shimura varieties parametrizing them have rarely rational points.

Published
2023

3. An Empirical Study of Personalized Federated Learning

Author

Matsuda, Koji, Sasaki, Yuya, Xiao, Chuan, and Onizuka, Makoto

Subjects
Computer Science - Machine Learning
Abstract

Federated learning is a distributed machine learning approach in which a single server and multiple clients collaboratively build machine learning models without sharing datasets on clients. A challenging issue of federated learning is data heterogeneity (i.e., data distributions may differ across clients). To cope with this issue, numerous federated learning methods aim at personalized federated learning and build optimized models for clients. Whereas existing studies empirically evaluated their own methods, the experimental settings (e.g., comparison methods, datasets, and client setting) in these studies differ from each other, and it is unclear which personalized federate learning method achieves the best performance and how much progress can be made by using these methods instead of standard (i.e., non-personalized) federated learning. In this paper, we benchmark the performance of existing personalized federated learning through comprehensive experiments to evaluate the characteristics of each method. Our experimental study shows that (1) there are no champion methods, (2) large data heterogeneity often leads to high accurate predictions, and (3) standard federated learning methods (e.g. FedAvg) with fine-tuning often outperform personalized federated learning methods. We open our benchmark tool FedBench for researchers to conduct experimental studies with various experimental settings.

Published
2022

5. Torsion points of elliptic curves over multi-quadratic number fields

Author

Matsuda, Koji

Subjects
Mathematics - Number Theory
Abstract

We compute the Mordell-Weil groups of the modular Jacobian varieties of hyperelliptic modular curves $X_1(M, MN)$ over every number field which is the composition of quadratic fields. Also we prove criteria for the existence of elliptic curves over such number fields with prescribed torsion points generalizing the results for quadratic number fields of Kamienny and Najman.

Published
2021

7. FedMe: Federated Learning via Model Exchange

Author

Matsuda, Koji, Sasaki, Yuya, Xiao, Chuan, and Onizuka, Makoto

Subjects
Computer Science - Machine Learning
Abstract

Federated learning is a distributed machine learning method in which a single server and multiple clients collaboratively build machine learning models without sharing datasets on clients. Numerous methods have been proposed to cope with the data heterogeneity issue in federated learning. Existing solutions require a model architecture tuned by the central server, yet a major technical challenge is that it is difficult to tune the model architecture due to the absence of local data on the central server. In this paper, we propose Federated learning via Model exchange (FedMe), which personalizes models with automatic model architecture tuning during the learning process. The novelty of FedMe lies in its learning process: clients exchange their models for model architecture tuning and model training. First, to optimize the model architectures for local data, clients tune their own personalized models by comparing to exchanged models and picking the one that yields the best performance. Second, clients train both personalized models and exchanged models by using deep mutual learning, in spite of different model architectures across the clients. We perform experiments on three real datasets and show that FedMe outperforms state-of-the-art federated learning methods while tuning model architectures automatically.

Published
2021

11. Endoscopist‐related factors affecting adenoma detection during colonoscopy: data from the J‐SCOUT study

Author

Kawamura, Takuji, primary, Sekiguchi, Masau, additional, Takamaru, Hiroyuki, additional, Mizuguchi, Yasuhiko, additional, Horiguchi, Go, additional, Toyoizumi, Hirobumi, additional, Kato, Masayuki, additional, Kobayashi, Kiyonori, additional, Sada, Miwa, additional, Oda, Yasushi, additional, Yokoyama, Akira, additional, Utsumi, Takahiro, additional, Tsuji, Yosuke, additional, Ohki, Daisuke, additional, Takeuchi, Yoji, additional, Shichijo, Satoki, additional, Ikematsu, Hiroaki, additional, Matsuda, Koji, additional, Teramukai, Satoshi, additional, Kobayashi, Nozomu, additional, Matsuda, Takahisa, additional, Saito, Yutaka, additional, and Tanaka, Kiyohito, additional

Published
2023
Full Text
View/download PDF

12. An overview of the Muara Laboh geothermal system, Sumatra

Author

Stimac, Jim, Ganefianto, Novi, Baroek, Marino, Sihotang, Mauliate, Ramadhan, Irvan, Mussofan, Wildan, Sidik, Ridwan, Alfiady, Dyaksa, Dayinta A., Azis, Herwin, Putra, Alfianto P., Martikno, Rudy, Irsamukhti, Robi, Santana, Sonny, Matsuda, Koji, Hatanaka, Hideki, Soeda, Yoshio, Cariou, Laurent, and Egermann, Patrick

Published
2019
Full Text
View/download PDF

13. Monitoring Geographical Entities with Temporal Awareness in Tweets

Author

Matsuda, Koji, Sango, Mizuki, Okazaki, Naoaki, Inui, Kentaro, Hutchison, David, Series Editor, Kanade, Takeo, Series Editor, Kittler, Josef, Series Editor, Kleinberg, Jon M., Series Editor, Mattern, Friedemann, Series Editor, Mitchell, John C., Series Editor, Naor, Moni, Series Editor, Pandu Rangan, C., Series Editor, Steffen, Bernhard, Series Editor, Terzopoulos, Demetri, Series Editor, Tygar, Doug, Series Editor, Weikum, Gerhard, Series Editor, and Gelbukh, Alexander, editor

Published
2018
Full Text
View/download PDF

14. Endoscopist‐related factors affecting adenoma detection during colonoscopy: Data from the J‐SCOUT study.

Author

Kawamura, Takuji, Sekiguchi, Masau, Takamaru, Hiroyuki, Mizuguchi, Yasuhiko, Horiguchi, Go, Toyoizumi, Hirobumi, Kato, Masayuki, Kobayashi, Kiyonori, Sada, Miwa, Oda, Yasushi, Yokoyama, Akira, Utsumi, Takahiro, Tsuji, Yosuke, Ohki, Daisuke, Takeuchi, Yoji, Shichijo, Satoki, Ikematsu, Hiroaki, Matsuda, Koji, Teramukai, Satoshi, and Kobayashi, Nozomu

Subjects
ADENOMA, COLONOSCOPY, DATABASES, ODDS ratio, CONFIDENCE intervals
Abstract

Objectives: Colonoscopy withdrawal times are associated with the adenoma detection rate (ADR). However, the relationship between ADR and cecal insertion time has been inadequately characterized. We aimed to evaluate endoscopist‐related factors involved in the ADR, including the average individual colonoscopy insertion and withdrawal times. Methods: This observational study used a colonoscopy database with pathology data from routine clinical practice in Japanese institutions. The odds ratios (OR) of endoscopist‐related factors related to ADRs were examined using a generalized linear mixed model. Results: Of the 186,293 colonoscopies performed during the study period, 47,705 colonoscopies by 189 endoscopists in four hospitals were analyzed for ADR. The overall ADR was 38.3% (95% confidence interval [CI] 37.8, 38.7). Compared to endoscopists with mean cecal insertion times of <5 min, the OR of ADR for those with mean cecal insertion times of 5–9, 10–14, and ≥15 min were 0.84 (95% CI 0.71, 0.99), 0.68 (95% CI 0.52, 0.90), and 0.45 (95% CI 0.25, 0.78), respectively. Compared to endoscopists with mean withdrawal times of <6 min, the OR of ADR for those with mean withdrawal times of 6–9, 10–14, and ≥15 min were 1.38 (95% CI 1.03, 1.85), 1.48 (95% CI 1.09, 2.02), and 1.68 (95% CI 1.04, 2.61), respectively. There were no significant differences in ADRs by endoscopist specialty, gender, or the total number of examinations performed. Conclusion: Individual mean colonoscopy insertion time was associated with ADR and might be considered as a colonoscopy quality indicator as well as withdrawal time. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

17. Optogenetic manipulation of neuronal and cardiomyocyte functions in zebrafish using microbial rhodopsins and adenylyl cyclases

Author

Hagio, Hanako, primary, Koyama, Wataru, primary, Hosaka, Shiori, additional, Song, Aysenur Deniz, additional, Narantsatsral, Janchiv, additional, Matsuda, Koji, additional, Shimizu, Takashi, additional, Hososhima, Shoko, additional, Tsunoda, Satoshi P, additional, Kandori, Hideki, additional, and Hibi, Masahiko, additional

Published
2023
Full Text
View/download PDF

18. Author response: Optogenetic manipulation of Gq- and Gi/o-coupled receptor signaling in neurons and heart muscle cells

Author

Hagio, Hanako, primary, Koyama, Wataru, primary, Hosaka, Shiori, additional, Song, Aysenur Deniz, additional, Narantsatsral, Janchiv, additional, Matsuda, Koji, additional, Sugihara, Tomohiro, additional, Shimizu, Takashi, additional, Koyanagi, Mitsumasa, additional, Terakita, Akihisa, additional, and Hibi, Masahiko, additional

Published
2023
Full Text
View/download PDF

19. Author response: Optogenetic manipulation of neuronal and cardiomyocyte functions in zebrafish using microbial rhodopsins and adenylyl cyclases

Author

Hagio, Hanako, primary, Koyama, Wataru, primary, Hosaka, Shiori, additional, Song, Aysenur Deniz, additional, Narantsatsral, Janchiv, additional, Matsuda, Koji, additional, Shimizu, Takashi, additional, Hososhima, Shoko, additional, Tsunoda, Satoshi P, additional, Kandori, Hideki, additional, and Hibi, Masahiko, additional

Published
2023
Full Text
View/download PDF

20. Current status of esophageal endoscopy including the evaluation of smoking and alcohol consumption in Japan: an analysis based on the Japan endoscopy database

Author

Katada, Chikatoshi, Horimatsu, Takahiro, Muto, Manabu, Tanaka, Kiyohito, Matsuda, Koji, Fujishiro, Mitsuhiro, Saito, Yutaka, Ohtsuka, Kazuo, Oda, Ichiro, Kato, Masayuki, Kida, Mitsuhiro, Kobayashi, Kiyonori, Hoteya, Shu, Kodashima, Shinya, Matsuda, Takahisa, Yamamoto, Hironori, Ryozawa, Shomei, Iwakiri, Ryuichi, Kutsumi, Hiromu, Miyata, Hiroaki, Kato, Mototsugu, Haruma, Ken, Fujimoto, Kazuma, Uemura, Naomi, Kaminishi, Michio, and Tajiri, Hisao

Published
2019
Full Text
View/download PDF

21. Detectability of colorectal neoplastic lesions using a novel endoscopic system with blue laser imaging: a multicenter randomized controlled trial

Author

Ikematsu, Hiroaki, Sakamoto, Taku, Togashi, Kazutomo, Yoshida, Naohisa, Hisabe, Takashi, Kiriyama, Shinsuke, Matsuda, Koji, Hayashi, Yoshikazu, Matsuda, Takahisa, Osera, Shozo, Kaneko, Kazuhiro, Utano, Kenichi, Naito, Yuji, Ishihara, Hiroshi, Kato, Masayuki, Yoshimura, Kenichi, Ishikawa, Hideki, Yamamoto, Hironori, and Saito, Yutaka

Published
2017
Full Text
View/download PDF

23. “Endoscopic” adenoma detection rate as a quality indicator of colonoscopy: First report from the J‐SCOUT study

Author

Kawamura, Takuji, primary, Sekiguchi, Masau, additional, Takamaru, Hiroyuki, additional, Mizuguchi, Yasuhiko, additional, Horiguchi, Go, additional, Kato, Masayuki, additional, Kobayashi, Kiyonori, additional, Sada, Miwa, additional, Oda, Yasushi, additional, Yokoyama, Akira, additional, Utsumi, Takahiro, additional, Tsuji, Yosuke, additional, Ohki, Daisuke, additional, Takeuchi, Yoji, additional, Shichijo, Satoki, additional, Ikematsu, Hiroaki, additional, Matsuda, Koji, additional, Teramukai, Satoshi, additional, Kobayashi, Nozomu, additional, Matsuda, Takahisa, additional, Saito, Yutaka, additional, and Tanaka, Kiyohito, additional

Published
2023
Full Text
View/download PDF

26. Optogenetic manipulation of second messengers in neurons and cardiomyocytes with microbial rhodopsins and adenylyl cyclase

Author

Hagio, Hanako, primary, Hosaka, Shiori, additional, Koyama, Wataru, additional, Song, Aysenur Deniz, additional, Narantsatsral, Janchiv, additional, Matsuda, Koji, additional, Shimizu, Takashi, additional, Hososhima, Shoko, additional, Tsunoda, Satoshi P, additional, Kandori, Hideaki, additional, and Hibi, Masahiko, additional

Published
2022
Full Text
View/download PDF

28. Rio de Janeiro Global Consensus on Landmarks, Definitions, and Classifications in Barrett’s Esophagus: World Endoscopy Organization Delphi Study

Author

Emura, Fabian, primary, Chandrasekar, Viveksandeep Thoguluva, additional, Hassan, Cesare, additional, Armstrong, David, additional, Messmann, Helmut, additional, Arantes, Vitor, additional, Araya, Raul, additional, Barrera-Leon, Oscar, additional, Bergman, Jacques J.G. H.M., additional, Bandhari, Pradeep, additional, Bourke, Michael J., additional, Cerisoli, Cecilio, additional, Chiu, Philip Wai-Yan, additional, Desai, Madhav, additional, Dinis-Ribeiro, Mário, additional, Falk, Gary W., additional, Fujishiro, Mitsuhiro, additional, Gaddam, Srinivas, additional, Goda, Kenichi, additional, Gross, Seth, additional, Haidry, Rehan, additional, Ho, Lawrence, additional, Iyer, Prasad G., additional, Kashin, Sergey, additional, Kothari, Shivangi, additional, Lee, Yeong Yeh, additional, Matsuda, Koji, additional, Neuhaus, Horst, additional, Oyama, Tsuneo, additional, Ragunath, Krish, additional, Repici, Alessandro, additional, Shaheen, Nicholas, additional, Singh, Rajvinder, additional, Sobrino-Cossio, Sergio, additional, Wang, Kenneth K., additional, Waxman, Irving, additional, and Sharma, Prateek, additional

Published
2022
Full Text
View/download PDF

29. First progress report on the Japan Endoscopy Database project

Author

Kodashima, Shinya, Tanaka, Kiyohito, Matsuda, Koji, Fujishiro, Mitsuhiro, Saito, Yutaka, Ohtsuka, Kazuo, Oda, Ichiro, Katada, Chikatoshi, Kato, Masayuki, Kida, Mitsuhiro, Kobayashi, Kiyonori, Hoteya, Shu, Horimatsu, Takahiro, Matsuda, Takahisa, Muto, Manabu, Yamamoto, Hironori, Ryozawa, Shomei, Iwakiri, Ryuichi, Kutsumi, Hiromu, Miyata, Hiroaki, Kato, Mototsugu, Haruma, Ken, Fujimoto, Kazuma, Uemura, Naomi, Kaminishi, Michio, and Tajiri, Hisao

Published
2018
Full Text
View/download PDF

30. Design paper: Japan Endoscopy Database (JED): A prospective, large database project related to gastroenterological endoscopy in Japan

Author

Matsuda, Koji, Tanaka, Kiyohito, Fujishiro, Mitsuhiro, Saito, Yutaka, Ohtsuka, Kazuo, Oda, Ichiro, Katada, Chikatoshi, Kato, Masayuki, Kida, Mitsuhiro, Kobayashi, Kiyonori, Hoteya, Shu, Horimatsu, Takahiro, Kodashima, Shinya, Matsuda, Takahisa, Muto, Manabu, Yamamoto, Hironori, Ryozawa, Shomei, Iwakiri, Ryuichi, Kutsumi, Hiromu, Miyata, Hiroaki, Kato, Mototsugu, Haruma, Ken, Fujimoto, Kazuma, Uemura, Naomi, Kaminishi, Michio, and Tajiri, Hisao

Published
2018
Full Text
View/download PDF

32. Sa1118 RISK OF COLORECTAL CANCER AMONG FECAL IMMUNOCHEMICAL TEST-POSITIVE INDIVIDUALS BY TIMING OF PREVIOUS COLONOSCOPY: A JAPANESE MULTICENTER ANALYSIS

Author

Kawamura, Takuji, Sekiguchi, Masau, Takamaru, Hiroyuki, Mizuguchi, Yasuhiko, Horiguchi, Go, Toyoizumi, Hirobumi, Kato, Masayuki, Kobayashi, Kiyonori, Sada, Miwa, Yasushi, Oda, Yokoyama, Akira, Utsumi, Takahiro, Tsuji, Yosuke, Ohki, Daisuke, Takeuchi, Yoji, Shichijo, Satoki, Ikematsu, Hiroaki, Matsuda, Koji, Teramukai, Satoshi, Kobayashi, Nozomu, Matsuda, Takahisa, Saito, Yutaka, and Tanaka, Kiyohito

Published
2024
Full Text
View/download PDF

34. PREVALENCE OF COLORECTAL NEUROENDOCRINE NEOPLASMS AND IMPACT OF ENDOSCOPIST FACTORS: RESULTS FROM LARGE-SCALE DATA OF COLONOSCOPIES IN JAPAN.

Author

Sekiguchi, Masau, Kawamura, Takuji, Takamaru, Hiroyuki, Mizuguchi, Yasuhiko, Horiguchi, Go, Toyoizumi, Hirobumi, Kato, Masayuki, Kobayashi, Kiyonori, Sada, Miwa, Yasushi, Oda, Yokoyama, Akira, Utsumi, Takahiro, Tsuji, Yosuke, Ohki, Daisuke, Takeuchi, Yoji, Shichijo, Satoki, Ikematsu, Hiroaki, Matsuda, Koji, Teramukai, Satoshi, and Kobayashi, Nozomu

Published
2024
Full Text
View/download PDF

40. Efficacy of endoscopic large balloon dilation extended for 2 minutes in bile duct stone removal: A multicenter retrospective study.

Author

Nakahara, Kazunari, Michikawa, Yosuke, Suetani, Keigo, Sato, Junya, Igarashi, Yosuke, Sekine, Akihiro, Kobayashi, Shinjiro, Matsuda, Koji, Otsubo, Takehito, and Itoh, Fumio

Abstract

Background/Purpose: There is no evidence regarding the optimal balloon dilation time during endoscopic papillary large balloon dilation (EPLBD). The study aim was to evaluate the efficacy of 2‐minute extended balloon dilation for EPLBD. Methods: Two hundred and five patients who underwent EPLBD during endoscopic retrograde cholangiopancreatography (ERCP) for bile duct stones at three tertiary centers were included in the analysis. Clinical outcomes and the adverse events were compared between the 0‐minute group (n = 94, balloon deflated immediately after waist disappearance) and the 2‐minute group (n = 111, balloon dilation maintained for 2 minutes after waist disappearance). The risk factors of post‐ERCP pancreatitis (PEP) after EPLBD were assessed. Results: There were no significant differences in the stone removal rates and hospitalization periods between the two groups. However, the total ERCP procedure time was significantly shorter in the 2‐minute group (40.6 vs 48.9 min, P =.03). The incidence of PEP was 7.4% in the 0‐minute group and significantly lower at 0.9% in the 2‐minute group (P =.04). Multivariate analysis identified without 2‐minute extended EPLBD as a significant risk factor of PEP (OR: 9.9, P =.045). Conclusions: Extension of EPLBD for 2 minutes helped prevent PEP and shortened the procedure time. [ABSTRACT FROM AUTHOR]

Published
2022
Full Text
View/download PDF

42. Current status of diagnostic and therapeutic colonoscopy in Japan: The Japan Endoscopic Database Project

Author

Saito, Yutaka, primary, Kodashima, Shinya, additional, Matsuda, Takahisa, additional, Matsuda, Koji, additional, Fujishiro, Mitsuhiro, additional, Tanaka, Kiyohito, additional, Kobayashi, Kiyonori, additional, Katada, Chikatoshi, additional, Horimatsu, Takahiro, additional, Muto, Manabu, additional, Ohtsuka, Kazuo, additional, Oda, Ichiro, additional, Kato, Masayuki, additional, Kida, Mitsuhiro, additional, Hoteya, Shu, additional, Yamamoto, Hironori, additional, Ryozawa, Shomei, additional, Iwakiri, Ryuichi, additional, Kutsumi, Hiromu, additional, Kato, Mototsugu, additional, Haruma, Ken, additional, Fujimoto, Kazuma, additional, Iishi, Hiroyasu, additional, Ogata, Haruhiko, additional, Uemura, Naomi, additional, Kaminishi, Michio, additional, Tajiri, Hisao, additional, and Inoue, Haruhiro, additional

Published
2021
Full Text
View/download PDF

45. Standardized endoscopic reporting

Author

Aabakken, Lars, Barkun, Alan N, Cotton, Peter B, Fedorov, Evgeny, Fujino, Masayuki A, Ivanova, Ekaterina, Kudo, Shin-ei, Kuznetzov, Konstantin, de Lange, Thomas, Matsuda, Koji, Moine, Olivier, Rembacken, Björn, Rey, Jean-Francois, Romagnuolo, Joseph, Rösch, Thomas, Sawhney, Mandeep, Yao, Kenshi, and Waye, Jerome D

Published
2014
Full Text
View/download PDF

49. Clinical Questions and Answers on Gastrointestinal Endoscopy during the Novel COVID‐19 Pandemic

Author

Furuta, Takahisa, Irisawa, Atsushi, Matsumoto, Takayuki, Kawai, Takashi, Inaba, Tomoki, Kanno, Atsushi, Katanuma, Akio, Kawahara, Yoshiro, Matsuda, Koji, Mizukami, Kazuhiro, Otsuka, Takao, Yasuda, Ichiro, Fujishiro, Mitsuhiro, Tanaka, Shinji, Fujimoto, Kazuma, Fukuda, Shinsaku, Iishi, Hiroyasu, Igarashi, Yoshinori, Inui, Kazuo, Ueki, Toshiharu, Ogata, Haruhiko, Kato, Mototsugu, Shiotani, Akiko, Higuchi, Kazuhide, Fujita, Naotaka, Murakami, Kazunari, Yamamoto, Hironori, Ito, Tohru, Okazaki, Kazuichi, Kitagawa, Yuko, Mine, Tetsuya, Tajiri, Hisao, and Inoue, Haruhiro

Subjects
Male, Infection Control, Safety Management, Infectious Disease Transmission, Patient-to-Professional, Pneumonia, Viral, COVID-19, Recommendation, gastrointestinal endoscopy, Endoscopy, Gastrointestinal, COVID‐19, Surveys and Questionnaires, personal protective equipment, Humans, Female, Coronavirus Infections, Pandemics, Occupational Health
Abstract

Some situations may require endoscopy during the COVID‐19 (Coronavirus Disease 2019) pandemic. Here, we describe the necessary precautions in the form of clinical questions and answers (Q&A) regarding the safe deployment of gastrointestinal endoscopy in such situations while protecting endoscopy staff and patients from infection. Non‐urgent endoscopy should be postponed. The risk of infection in patients should be evaluated in advance by questionnaire and body temperature. The health of staff must be checked every day. Decisions to employ endoscopy should be based on the institutional conditions and aims of endoscopy. All endoscopic staffs need to wear appropriate personal protective equipment (PPE). The endoscope and other devices should be cleaned and disinfected after procedures in accordance with relevant guidelines. Optimal management of the endoscopy unit is required. Endoscopy for infected patients or those with suspected infection demands exceptional caution. When a patient who undergoes endoscopy is later found to have COVID‐19, the members of staff involved are considered exposed to the virus and must not work for at least 14 days if their PPE is considered insufficient. When PPE resources are limited, some equipment may be used continuously throughout a shift as long as it is not contaminated. Details of the aforementioned protective measures are described.

Published
2020

Catalog

Books, media, physical & digital resources
See catalog results