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363 results on '"Yokota, Yusuke"'

185. Querying Multiple Video Streams and Hypermedia Objects of a Video-Based Virtual Space System.

Author

Besselaar, Peter, Koizumi, Satoshi, Yokota, Yusuke, He, Shumian, and Kambayashi, Yahiko

Abstract

By using several digital video cameras with omni-directional sensors, complete views of the activities at some place can be recorded as omni-directional videos. We utilize this technique for developing the Retrax System, which provides video-based virtual space environments as part of the Digital City infrastructure. The system aims to realize applications that are not possible with conventional video database systems, such as human activities and communications on computer networks based on recorded video data. This system archives the activities at some place in the real world and provides a virtual space based on the archived data for collaboration among users, such as walking, annotating, and communication. The user interface of the system bridges the real and virtual spaces or past and current human activities. This paper describes the purpose and usage of the system, and then introduces its architecture, data models, and the query language. Because both video data and hypermedia data are essential to the system, a query mechanism dealing with both types of data is required. The proposed query language is designed as an extension of SQL and realizes flexible management of both types of data. [ABSTRACT FROM AUTHOR]

Published
2005
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186. Part I: Cyber Space Database Systems: Database Support for Cooperative Work.

Author

Yokota, Yusuke, Kambayashi, Yahiko, Kitsuregawa, Masaru, Makinouchi, Akifumi, Uemura, Shunsuke, Tanaka, Katsumi, and Masunaga, Yoshifumi

Subjects
COMPUTER-supported cooperative work, TELEMATICS, COMPUTER networks, INTERACTIVE multimedia, DATABASES
Abstract

Most of CSCW applications are implemented as network applications, which support cooperation among users in distributed network environment. Such applications have to provide facilities of sharing and modification of resources for collaboration. Databases are suitable for foundations of these facilities because of its characteristics: separation of data and applications, support of distributed environment, transaction management, and data integrity. To realize some requirements from CSCW systems, extension of database functions are needed. We introduce a cooperative hypermedia system VIEW Media, which is based on database technologies and behaves as a framework for CSCW systems. The system has features of database systems and realizes development of flexible cooperative work application. [ABSTRACT FROM AUTHOR]

Published
2002

187. Seafloor geodetic constraints on interplate coupling of the Nankai Trough megathrust zone

Author

Yokota, Yusuke, Ishikawa, Tadashi, Watanabe, Shun-ichi, Tashiro, Toshiharu, and Asada, Akira

Abstract

Seafloor geodetic data from the Nankai Trough, off southwestern Japan, show that most offshore sites in this earthquake-prone region have high slip-deficit rates, revealing previously unknown locations that could be important for the mitigation of future earthquake- and tsunami-associated disasters.

Published
2016
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189. Co- and postseismic slip behaviors extracted from decadal seafloor geodesy after the 2011 Tohoku-oki earthquake

Author

Watanabe, Shun-ichi, Ishikawa, Tadashi, Nakamura, Yuto, and Yokota, Yusuke

Abstract

Investigations of the co- and postseismic processes of the 2011 Tohoku-oki earthquake provide essential information on the seismic cycle in the Japan Trench. Although almost all of the source region lies beneath the seafloor, recent seafloor geophysical instruments have enabled to detect the near-field signals of both the coseismic rupture and the postseismic stress relaxation phenomena. Annual-scale seafloor geodesy contributed to refining the postseismic deformation models, specifically to the incorporation of viscoelastic effects. However, because of the insufficiency in the spatial coverage and observation period of seafloor geodetic observations, no consensus on crustal deformation models has been reached, especially on the along-strike extent of the main rupture, even for the coseismic process. To decompose the postseismic transient processes in and around the source region, i.e., viscoelastic relaxation and afterslip, long-term postseismic geodetic observations on the seafloor play an essential role. Here, from decadal seafloor geodetic data, we provide empirical evidence for offshore aseismic afterslip on the rupture edges that had almost decayed within 2–3 year. The afterslip regions are considered to have stopped the north–south rupture propagation due to their velocity strengthening frictional properties. In the southern source region (~ 37° N), despite not being resolved by coseismic geodetic data, shallow tsunamigenic slip near the trench is inferred from postseismic seafloor geodesy as a subsequent viscoelastic deformation causing persistent seafloor subsidence at a geodetic site off-Fukushima. After a decade from the earthquake, the long-term viscoelastic relaxation process in the oceanic asthenosphere is currently in progress and is still dominant not only in the rupture area, but also in the off-Fukushima region.

Published
2021
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190. Prognostic value of a mandibular canal staging system for primary lesions in patients with lower gingival squamous cell carcinoma: a multicenter, retrospective study.

Author

Yamakawa, Nobuhiro, Okura, Masaya, Hasegawa, Takumi, Otsuru, Mitsunobu, Sakai, Hironori, Hirai, Eiji, Rin, Shin, Yamada, Shin-ichi, Yanamoto, Souichi, Yokota, Yusuke, Umeda, Masahiro, Kurita, Hiroshi, Ueda, Michihiro, Akashi, Masaya, and Kirita, Tadaaki

Subjects
*PROGNOSIS, *SQUAMOUS cell carcinoma, *GINGIVA, *MANDIBULAR fractures, *KAPLAN-Meier estimator, *TUMOR classification
Abstract

Background: The Union for International Cancer Control and American Joint Committee on Cancer tumor staging system is used globally for treatment planning. As it may be insufficient for tumor staging of lower gingival carcinomas, we proposed the mandibular canal tumor staging system. In this study, we aimed to compare the two systems for such tumor staging and to identify prognostic markers. Methods: This multicenter, retrospective study included patients with lower gingival squamous cell carcinoma who underwent radical surgery during 2001–2018. We compared survival rates (Kaplan–Meier estimator) and patient stratification according to the two systems. Results: The proposed system yielded more balanced patient stratification than the existing system. Progression in the tumor grade according to the proposed system was associated with a poorer prognosis. The 5-year overall and disease-specific survival rates for the entire cohort were 74.9% and 81.8%, respectively. Independent factors affecting overall survival were tumor stage according to the proposed system, excision margins, and number of positive nodes, whereas those affecting disease-specific survival were excision margins and number of positive nodes. Conclusions: Subsite-specific tumor classification should be used for patients with oral cancer, and our results suggest that mandibular canal tumor classification may be effective for patients with lower gingival carcinoma. [ABSTRACT FROM AUTHOR]

Published
2024
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191. Bone microstructural characteristics or positional changes of condyle head affect short-term condyle head resorption after orthognathic surgery

Author

Miyagawa, Kazuaki, Arikawa, Chihiro, Hayashi, Koichi, Seki, Soju, Yokota, Yusuke, Harada, Kazuma, Tanaka, Susumu, Isomura, Emiko Tanaka, Miyagawa, Kazuaki, Arikawa, Chihiro, Hayashi, Koichi, Seki, Soju, Yokota, Yusuke, Harada, Kazuma, Tanaka, Susumu, and Isomura, Emiko Tanaka

Abstract

Miyagawa K., Arikawa C., Hayashi K., et al. Bone microstructural characteristics or positional changes of condyle head affect short-term condyle head resorption after orthognathic surgery. Scientific Reports 14, 14269 (2024); https://doi.org/10.1038/s41598-024-65077-2., Condylar resorption occurs in some cases after orthognathic surgery, and the risk factors associated with postoperative condylar head resorption have been extensively described. Nevertheless, even in cases with a combination of risk factors, postoperative condylar resorption may not appear. This study analyzed the microstructure and three-dimensional positional change of the condylar bone via imaging in patients who have undergone bimaxillary orthognathic surgery to determine whether the microstructure or condylar position differs between patients with and without postoperative condylar resorption. Among asymptomatic patients who underwent bimaxillary surgery between April 2021 and March 2022 at our department, 17 patients were analyzed, limited to “female,” “skeletal Class II,” and “high-angle cases,” which are known risk factors for mandibular head resorption. Multidetector computed tomography was performed on these patients before and 6 months after surgery, and the bone microstructure of the condylar head and the three-dimensional positional changes of the condylar bone and the proximal bony fragments were compared with the presence of postoperative condyle resorption using the bone morphology software TRI/3D-BON. Patients with condylar bone abnormalities before surgery and those with high trabecular bone density can develop postoperative resorption if the condyle is misaligned by surgery.

192. Bone microstructural characteristics or positional changes of condyle head affect short-term condyle head resorption after orthognathic surgery

Author

Miyagawa, Kazuaki, Arikawa, Chihiro, Hayashi, Koichi, Seki, Soju, Yokota, Yusuke, Harada, Kazuma, Tanaka, Susumu, Isomura, Emiko Tanaka, Miyagawa, Kazuaki, Arikawa, Chihiro, Hayashi, Koichi, Seki, Soju, Yokota, Yusuke, Harada, Kazuma, Tanaka, Susumu, and Isomura, Emiko Tanaka

Abstract

Miyagawa K., Arikawa C., Hayashi K., et al. Bone microstructural characteristics or positional changes of condyle head affect short-term condyle head resorption after orthognathic surgery. Scientific Reports 14, 14269 (2024); https://doi.org/10.1038/s41598-024-65077-2., Condylar resorption occurs in some cases after orthognathic surgery, and the risk factors associated with postoperative condylar head resorption have been extensively described. Nevertheless, even in cases with a combination of risk factors, postoperative condylar resorption may not appear. This study analyzed the microstructure and three-dimensional positional change of the condylar bone via imaging in patients who have undergone bimaxillary orthognathic surgery to determine whether the microstructure or condylar position differs between patients with and without postoperative condylar resorption. Among asymptomatic patients who underwent bimaxillary surgery between April 2021 and March 2022 at our department, 17 patients were analyzed, limited to “female,” “skeletal Class II,” and “high-angle cases,” which are known risk factors for mandibular head resorption. Multidetector computed tomography was performed on these patients before and 6 months after surgery, and the bone microstructure of the condylar head and the three-dimensional positional changes of the condylar bone and the proximal bony fragments were compared with the presence of postoperative condyle resorption using the bone morphology software TRI/3D-BON. Patients with condylar bone abnormalities before surgery and those with high trabecular bone density can develop postoperative resorption if the condyle is misaligned by surgery.

193. General Factors and Dental-Related Risk Factors for Postoperative Pneumonia or Infectious Complications: A Retrospective Study

Author

Isomura, Emiko Tanaka, Fujimoto, Yukari, Matsukawa, Makoto, Yokota, Yusuke, Urakawa, Ryuta, Tanaka, Susumu, Isomura, Emiko Tanaka, Fujimoto, Yukari, Matsukawa, Makoto, Yokota, Yusuke, Urakawa, Ryuta, and Tanaka, Susumu

Abstract

Isomura E.T., Fujimoto Y., Matsukawa M., et al. General Factors and Dental-Related Risk Factors for Postoperative Pneumonia or Infectious Complications: A Retrospective Study. Journal of Clinical Medicine 12, 3529 (2023); https://doi.org/10.3390/jcm12103529., Numerous studies report that perioperative oral care decreases the frequency of postoperative pneumonia or infection. However, no studies have analyzed the specific impact of oral infection sources on the postoperative course, and the criteria for preoperative dental care differ among institutions. This study aimed to analyze the factors and dental conditions present in patients with postoperative pneumonia and infection. Our results suggest that general factors related to postoperative pneumonia, including thoracic surgery, sex (male > female), the presence or absence of perioperative oral management, smoking history, and operation time, were identified, but there were no dental-related risk factors associated with it. However, the only general factor related to postoperative infectious complications was operation time, and the only dental-related risk factor was periodontal pocket (4 mm or higher). These results suggest that oral management immediately before surgery is sufficient to prevent postoperative pneumonia, but that moderate periodontal disease must be eliminated to prevent postoperative infectious complication, which requires periodontal treatment not only immediately before surgery, but also on a daily basis.

194. General Factors and Dental-Related Risk Factors for Postoperative Pneumonia or Infectious Complications: A Retrospective Study

Author

Isomura, Emiko Tanaka, Fujimoto, Yukari, Matsukawa, Makoto, Yokota, Yusuke, Urakawa, Ryuta, Tanaka, Susumu, Isomura, Emiko Tanaka, Fujimoto, Yukari, Matsukawa, Makoto, Yokota, Yusuke, Urakawa, Ryuta, and Tanaka, Susumu

Abstract

Isomura E.T., Fujimoto Y., Matsukawa M., et al. General Factors and Dental-Related Risk Factors for Postoperative Pneumonia or Infectious Complications: A Retrospective Study. Journal of Clinical Medicine 12, 3529 (2023); https://doi.org/10.3390/jcm12103529., Numerous studies report that perioperative oral care decreases the frequency of postoperative pneumonia or infection. However, no studies have analyzed the specific impact of oral infection sources on the postoperative course, and the criteria for preoperative dental care differ among institutions. This study aimed to analyze the factors and dental conditions present in patients with postoperative pneumonia and infection. Our results suggest that general factors related to postoperative pneumonia, including thoracic surgery, sex (male > female), the presence or absence of perioperative oral management, smoking history, and operation time, were identified, but there were no dental-related risk factors associated with it. However, the only general factor related to postoperative infectious complications was operation time, and the only dental-related risk factor was periodontal pocket (4 mm or higher). These results suggest that oral management immediately before surgery is sufficient to prevent postoperative pneumonia, but that moderate periodontal disease must be eliminated to prevent postoperative infectious complication, which requires periodontal treatment not only immediately before surgery, but also on a daily basis.

196. Full-Bayes GNSS-A solutions for precise seafloor positioning with single uniform sound speed gradient layer assumption.

Author

Watanabe, Shun-ichi, Ishikawa, Tadashi, Nakamura, Yuto, and Yokota, Yusuke

Abstract

A systematic analysis methodology for precise seafloor positioning using the GNSS-A has been constructed and implemented in the open-source software GARPOS. It introduces a linearized perturbation field model for extraction of the 4-dimensional sound speed variation, and solves the perturbation parameters simultaneously with the seafloor position based on the empirical Bayes approach. Although it can provide the solutions stably and almost analytically, it has less expandability when imposing additional nonlinear constraint parameters in the observation equation. Even though such parameters can be optimized by applying some information criteria, information on the details of the joint posterior probability would be lost and only the conditional posterior can be estimated. To overcome the above limitations, we implemented full-Bayes estimation using the Markov-Chain Monte Carlo algorithm. This approach can not only help evaluate the dependency of the existing constraint parameters on the seafloor position, but also let us discuss the effects of the additionally imposed constraints. We imposed a constraint under the assumption that a temporally-variable gradient layer steadily lies at a certain depth in the observation scale (typically < 10 km × 10 km, < 1 day). This models the cases with temperature gradients due to a large-scale structure such as the Kuroshio current or internal waves with long-wavelength. The constraint narrows the posterior of the horizontal position and provides a better solution for many datasets, especially in the Nankai Trough region. For the other datasets, the constraint emphasized bias errors, which can also provide information on the possibility of instrumental and modelling errors. [ABSTRACT FROM AUTHOR]

Published
2023
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197. Non-volcanic crustal movements of the northernmost Philippine Sea plate detected by the GPS-acoustic seafloor positioning

Author

Watanabe, Shun-ichi, Ishikawa, Tadashi, and Yokota, Yusuke

Abstract

Repeatedly performing the GPS-acoustic seafloor positioning, we first succeeded in detecting non-volcanic seafloor movements on the Philippine Sea plate (PHS) subducting along the Sagami Trough. At a seafloor geodetic site on the northernmost part of the PHS off the Boso Peninsula, we detected significant eastward motion with respect to the central part of the PHS. This is unaccountable by the coupling between the Pacific plate and the PHS along the Izu-Bonin (Ogasawara) Trench because it would cause the westward elastic deformation at BOSS. It is rather consistent with the rigid motion of the tectonic block in the fore-arc along the Izu-Bonin Trench, associated with the back-arc rift. The other site on the western side of the Sagami Bay had moved toward the north relative to the Izu Peninsula. It suggests that the Izu microplate obviously moves relative to the northern PHS. The difference between the velocities of the Sagami Bay and the Izu Peninsula indicates the coupling on the boundary fault as well.

Published
2015
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198. Not brushing teeth at night may increase the risk of cardiovascular disease.

Author

Isomura, Emiko Tanaka, Suna, Shinichiro, Kurakami, Hiroyuki, Hikoso, Shungo, Uchihashi, Toshihiro, Yokota, Yusuke, Sakata, Yasushi, and Tanaka, Susumu

Subjects
*TOOTHBRUSHES, *CARDIOVASCULAR diseases risk factors, *CARDIOVASCULAR diseases, *TOOTH sensitivity, *MULTIVARIATE analysis, *THERAPEUTICS
Abstract

In this study, we investigated whether toothbrushing timing affects cardiovascular disease risk. We enrolled 1675 patients aged ≥ 20 years who were hospitalized for surgery, examination, or medical treatment. The participants were categorized as follows based on toothbrushing: Group MN (brushing teeth after waking up and at night, n = 409), Group Night (brushing teeth at night but not upon waking up, n = 751), Group M (brushing teeth after waking up but not at night, n = 164), and Group None (not brushing teeth at all, n = 259). The participants' age, sex, smoking history, and follow-up results were evaluated. Group M had four times as many men as women. Multivariate analysis of cardiovascular events showed significantly higher survival estimates in Group MN (P = 0.021) and Group Night (P = 0.004) than in Group None. Kaplan–Meier analysis of subgroups based on smoking status revealed that smokers in Group None had significantly worse prognosis for cardiovascular onset events than smokers in other groups; non-smokers in Groups None and M showed significantly worse prognosis on hospitalization. Our findings are limited to cardiovascular diseases and cannot be generalized to healthy populations. However, we suggest that brushing teeth at night is important for lowering cardiovascular disease risk. [ABSTRACT FROM AUTHOR]

Published
2023
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199. General Factors and Dental-Related Risk Factors for Postoperative Pneumonia or Infectious Complications: A Retrospective Study.

Author

Isomura, Emiko Tanaka, Fujimoto, Yukari, Matsukawa, Makoto, Yokota, Yusuke, Urakawa, Ryuta, and Tanaka, Susumu

Subjects
*PREOPERATIVE risk factors, *THORACIC surgery, *PNEUMONIA, *PERIODONTAL pockets, *PERIOPERATIVE care, *PREOPERATIVE care
Abstract

Numerous studies report that perioperative oral care decreases the frequency of postoperative pneumonia or infection. However, no studies have analyzed the specific impact of oral infection sources on the postoperative course, and the criteria for preoperative dental care differ among institutions. This study aimed to analyze the factors and dental conditions present in patients with postoperative pneumonia and infection. Our results suggest that general factors related to postoperative pneumonia, including thoracic surgery, sex (male > female), the presence or absence of perioperative oral management, smoking history, and operation time, were identified, but there were no dental-related risk factors associated with it. However, the only general factor related to postoperative infectious complications was operation time, and the only dental-related risk factor was periodontal pocket (4 mm or higher). These results suggest that oral management immediately before surgery is sufficient to prevent postoperative pneumonia, but that moderate periodontal disease must be eliminated to prevent postoperative infectious complication, which requires periodontal treatment not only immediately before surgery, but also on a daily basis. [ABSTRACT FROM AUTHOR]

Published
2023
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