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Advances in Polar Science 2013年第1期24卷 42-49页

作者： Akimitsu Ichihara Nozomu Nishitani tadahiko ogawa Takuya Tsugawa Solar-Terrestrial Environment Laboratory Nagoya University National Institute of Information and Communications Technology

We report on the characteristics of nighttime medium-scale traveling ionospheric disturbances （MSTIDs） propagating northward observed with the SuperDARN Hokkaido HF radar, which has a field of view to the north of Japan, and occasionally with the GNSS Earth Observation NETwork （GEONET）, which provides total electron content （TEC） data over Japan. From statis- tical analysis of MSTIDs observed with the Hokkaido radar during nighttime （1700-0700 LT） from January 2007 to July 2009, we find that these MSTIDs traveling northward, although rare in comparison with those traveling southwestward, have a relatively high occurrence rate after sunset and around midnight in May and August, which is partly consistent with the occurrence rate of MSTIDs over Japan observed with GEONET in 2002, when the MSTID event database is available. We also use the data from simultaneous observation of nightside MSTIDs by the Hokkaido radar and GEONET to find that when the HF radar observed northward-propagating MSTIDs, GEONET did not always observe such MSTIDs with the same propagation direction. Judging from this result and considering the HF radar field of view located to the north of the GEONET coverage area, we speculate that some physical parameters of the ionosphere/thermosphere over Japan differ from those to the north of Japan, which may result in the inconsistency of MSTID propagation direction. The present results provide new knowledge of MSTIDs propagating northward using the Hokkaido radar, whose field of view was not covered by GEONET.

关键词： SuperDARN Hokkaido radar GEONET MSTID

Investigation of Inside-Out Tracking Methods for Six Degrees of Freedom Pose Estimation of a Smartphone in Augmented Reality

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Computers, Materials & Continua 2024年第5期79卷 3047-3065页

作者： Chanho Park Takefumi ogawa Graduate School of Engineering The University of TokyoTokyo113-0033Japan Information Technology Center The University of TokyoChiba277-0882Japan

Six degrees of freedom(6DoF)input interfaces are essential formanipulating virtual objects through translation or rotation in three-dimensional(3D)space.A traditional outside-in tracking controller requires the installation of expensive hardware in *** inside-out tracking controllers have been proposed,they often suffer from limitations such as interaction limited to the tracking range of the sensor(e.g.,a sensor on the head-mounted display(HMD))or the need for pose value modification to function as an input interface(e.g.,a sensor on the controller).This study investigates 6DoF pose estimation methods without restricting the tracking range,using a smartphone as a controller in augmented reality(AR)*** approach involves proposing methods for estimating the initial pose of the controller and correcting the pose using an inside-out tracking *** addition,seven pose estimation algorithms were presented as candidates depending on the tracking range of the device sensor,the tracking method(e.g.,marker recognition,visual-inertial odometry(VIO)),and whether modification of the initial pose is *** two experiments(discrete and continuous data),the performance of the algorithms was *** results demonstrate enhanced final pose accuracy achieved by correcting the initial ***,the importance of selecting the tracking algorithm based on the tracking range of the devices and the actual input value of the 3D interaction was emphasized.

关键词： Smartphone inside-out tracking 6DoF pose 3D interaction augmented reality

External defects and severity level evaluation of potato using single and multispectral imaging in near infrared region Author links open overlay panel

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Information Processing in Agriculture 2024年第1期11卷 80-90页

作者： Dimas Firmanda Al Riza Slamet Widodo Kazuya Yamamoto Kazunori Ninomiya Tetsuhito Suzuki Yuichi ogawa Naoshi Kondo Laboratory of Biosensing Engineering Graduate School of AgricultureKyoto UniversityKitashirakawaKyoto 6068267Japan Department of Biosystems Engineering Faculty of Agricultural TechnologyUniversitas BrawijayaJl.VeteranMalang 65145Indonesia Department of Mechanical and Biosystem Engineering Bogor Agricultural UniversityJl.Raya Darmaga Kampus IPB DarmagaBogor 16680Indonesia Technology Development Department Shibuya Seiki Co.Ltd.66Takaoka-choMatsuyamaEhime 7918036Japan

Non-invasive potato defects detection has been demanded for sorting and grading *** on the classification of the defects has been available,however,investigation on the severity level calculation is *** the detection of the common scab,it has been found that imaging in the infrared region provide an interesting characteristic that could distinguish defected area to normal ***,investigations on this wavelength range is interesting to add more knowledge and for *** this research,the multispectral image has been obtained and investigated especially at three wavelengths(950,1150,1600 nm).Image pre-processing and pseudo-color conversion techniques were explored to enhance the contrast between defects,normal background skin area and soil *** show that external defects,such as common scab and some mechanical damage types,appear brighter in the near infrared region,especially at 1600 nm against the normal skin *** has been found that pseudo-color images conversion provides more information regarding type if surface characteristics compared to grayscale single *** segmentation using pseudo-color images after multiplication operation pre-processing could be used for common scab and mechanical damage detection excluding soil deposits with a Dice Sorensen coefficient of *** addition,image segmentation using single image at 1600 nm shown relatively better results with Dice Sorensen coefficient of 0.72 with note that thick soil deposits will also be *** severity level evaluation had an R2 correlation of 0.84 against standard measurements of severity.

关键词： Multispectral imaging Pseudo-color Common scab External defects Near infrared

Accuracy and Utility of Vessel Analysis Using Non-Contrast CT for Planning Endovascular Aortic Repair

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Open Journal of Medical Imaging 2024年第3期14卷 96-105页

作者： Midori Komita-Moriya Yukihisa ogawa Akiyuki Kotoku Shintaro Nawata Kenji Kuramochi Yasuyoshi ogawa Kiyoshi Chiba Hiroshi Nishimaki Hidefumi Mimura Department of Radiology St. Marianna University School of Medicine Kanagawa Japan Department of Radiology Tokai University School of Medicine Hachioji Hospital Tokyo Japan Radiological Technology St. Marianna University School of Medicine Kanagawa Japan Department of Cardiovascular Surgery St. Marianna University School of Medicine Kanagawa Japan

Objectives: This study aimed to determine whether errors in vascular measurements would affect device selection in endovascular aortic repair (EVAR) by comparing measurements obtained using non-contrast computed tomography (NCT) with those obtained using contrast-enhanced CT (CECT). Materials and Methods: This single-center, retrospective study included 25 patients who underwent EVAR for abdominal aortic aneurysm at our institution. A 1-mm horizontal cross-sectional slice of NCT and CECT from each patient was retrospectively reviewed. The area from the abdominal aorta to the common iliac artery was divided into four zones. A centerline was created using the NCT by manually plotting the center points. Subsequently, the centerlines were automatically extracted and manually corrected during the arterial phase of CECT. The diameter and length of each zone were measured for each modality. The mean diameters and lengths of the target vessels were compared between NCT and CECT. Results: The measurements obtained using both methods were reproducible and demonstrated good agreement. The mean differences in vessel length and diameter measurements for each segment between NCT and CECT were not statistically significant, indicating good consistency. Conclusion: NCT may be useful for preoperative EVAR evaluation in patients with renal dysfunction or allergies to contrast agents.

关键词： Non-Contrast CT Vessel Analysis EVAR Contrast-Enhanced CT Abdominal Aortic Aneurysm

Preoperative albumin-bilirubin score and liver resection percentage determine postoperative liver regeneration after partial hepatectomy

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World Journal of Gastroenterology 2024年第14期30卷 2006-2017页

作者： Kazuhiro Takahashi Masahiko Gosho Yoshihiro Miyazaki Hiromitsu Nakahashi Osamu Shimomura Kinji Furuya Manami Doi Yohei Owada Koichi ogawa Yusuke Ohara Yoshimasa Akashi Tsuyoshi Enomoto Shinji Hashimoto Tatsuya Oda Department of Gastrointestinal and Hepatobiliary-Pancreatic Surgery University of TsukubaTsukuba 3058-575IbarakiJapan Department of Biostatistics University of TsukubaTsukuba 3058-575IbarakiJapan

BACKGROUND The success of liver resection relies on the ability of the remnant liver to *** of the knowledge regarding the pathophysiological basis of liver regeneration comes from rodent studies,and data on humans are ***,there is limited knowledge about the preoperative factors that influence postoperative *** To quantify postoperative remnant liver volume by the latest volumetric software and investigate perioperative factors that affect posthepatectomy liver *** A total of 268 patients who received partial hepatectomy were *** were grouped into right hepatectomy/trisegmentectomy(RH/Tri),left hepa-tectomy(LH),segmentectomy(Seg),and subsegmentectomy/nonanatomical hepatectomy(Sub/Non)*** regeneration index(RI)and late rege-neration rate were defined as(postoperative liver volume)/[total functional liver volume(TFLV)]×100 and(RI at 6-months-RI at 3-months)/RI at 6-months,*** lower 25th percentile of RI and the higher 25th percentile of late regeneration rate in each group were defined as“low regeneration”and“delayed regeneration”.“Restoration to the original size”was defined as regeneration of the liver volume by more than 90%of the TFLV at 12 months *** The numbers of patients in the RH/Tri,LH,Seg,and Sub/Non groups were 41,53,99 and 75,*** RI plateaued at 3 months in the LH,Seg,and Sub/Non groups,whereas the RI increased until 12 months in the RH/Tri *** to our multivariate analysis,the preoperative albumin-bilirubin(ALBI)score was an independent factor for low regeneration at 3 months[odds ratio(OR)95%CI=2.80(1.17-6.69),P=0.02;per 1.0 up]and 12 months[OR=2.27(1.01-5.09),P=0.04;per 1.0 up].Multivariate analysis revealed that only liver resection percentage[OR=1.03(1.00-1.05),P=0.04]was associated with delayed ***,multivariate analysis demonstrated that the preoperative ALBI score[OR=2.63(1.00-1.05),P=0.02;per 1.

关键词： Liver regeneration Albumin-bilirubin score Liver resection percentage Partial hepatectomy Human Regeneration index

Estimations of the Maximum Tangential Velocity V_(θm) in the Vortex Core Region and also the Mean Rotational Velocity V_(oi) near the Concave Wall Surface in the Returned Flow Type Cyclone Dust Collector

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Journal of Thermal Science 2010年第6期19卷 553-560页

作者： Akira ogawa T 110-0011. Minowa 2-14-7 Taitou-Ku Tokyo Japan

There are many types of cyclone dust collectors for separating the fine solid and dust particles from gases in the various industries and also in the home used purposes. For estimating the power loss and the collection efficiency, one of the most important factors is the maximum tangential velocity V0m in the vortex core region in the cyclone body. In order to determine V0~ by the simple method, it is useful to apply the mechanical balance of the angular momentum fluxes under the assumption of ogawa combined vortex model which is composed of the quasi-forced vortex in the vortex core region and also the quasi-free vortex surrounded the vortex core region and also under the assumption of the introduction of equivalent length Heq corresponding to the cone spaces of the cyclone body and the dust bunker. On the other hand, the mean rotational velocity Voi near the concave wall surface is also estimated by the mechanical balance of angular momentum fluxes with the moment of viscous friction force. For confirming the general applications of the obtained equations, the returned flow types cyclones changed the throat diameter D3 are designed. The material of the cyclone is the transparent acrylic resin. Therefore the inner surface of the cyclone body can be regarded as smooth surface. The comparisons of the measured velocities V~ and Voi by a cylindrical Pitot tube are shown in good agreement with those of the proposed equations. The above stated results are described in detail.

关键词： Cyclone Dust Collector Maximum Tangential Velocity Mean Rotational Velocity Angular Momentum Flux Equivalent Length Surface Frictional Force ogawa Combined Vortex Model Reynolds Number.

Effects of loading contact on electric-power generation of lead zirconate titanate piezoelectric ceramic plate

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Journal of Advanced Ceramics 2019年第4期8卷 509-518页

作者： Mitsuhiro OKAYASU Tsukasa ogawa Graduate School of Natural Science and Technology Okayama University

To better understand the generation of electric power for piezoelectric Pb Zr Ti O3(PZT)ceramic plate(?25 mm),an attempt was made to investigate experimentally and numerically electricpower generation characteristics during cyclic bending under various loading fixtures(?0–?20 mm),i.e.,different contact *** the load-contact area on the PZT ceramic leads to a nonlinear decrease in the generated *** contact area basically enhances the generated voltage,although the voltage saturates during loading when the contact area is less than?5 mm.A similar voltage is generated for?0 and?5 mm,which is attributed to strain status(ratio of compressive and tensile strain)and material failure due to different stress distribution in the PZT *** the basis of the obtained electric generation voltage,suitable loading conditions are clarified by loading with the?5 mm fixture,which generates a higher voltage and a longer lifetime of the PZT *** this approach,it is appeared that the area contact with the area ratio of 0.04(?5 mm/?20 mm)is suitable to obtain the high efficiency of the electric voltage.

关键词： piezoelectric ceramic lead zirconate titanate ceramic electric power generation

Spin-up and Spin-Down Times of Rotational Air Flow Depended on Mean Air Velocity and Surface Roughness on Inner Surface in Cylindrical Vortex Chamber

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Journal of Thermal Science 2004年第1期13卷 46-55页

作者： Akira ogawa Hiroyuki Murakami Department of Mechanical Eng.College of Eng. Nihon UniversityT-963.TokusadaTamura-machiKooriyama-CityJapanThe Marine Self Defense Forcethe Defense AgencyJapan

The spin-up time TA in the spin-up process and spin-down time TD in the spin-down process of rotational air flow in the cylindrical vortex chamber with three kinds of the artificial surface roughness were investigated. One of the most different characteristics between the smooth and rough surface conditions was the spin-down time TD. Also the transient response of the tangential velocity on the spin-up process was analyzed numerically and this result was compared with the experimental results. The above stated results are reported here in detail.

关键词： vortex chamber spin-up time spin-down time transient response surface roughness.

Control of Collection Efficiency for Axial Flow Cyclone Dust Collectors with Fixed Guide Vanes and with Funnel Shaped Exit Pipes

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Journal of Thermal Science 2006年第3期15卷 240-250页

作者： Akira ogawa Masaru Arakawa T-110-0011 Minowa 2-14-7Taitou-KuTokyoJapan SHINWA RULES Co. Ltd.Sanjo-ShiNiigataJapan

The experimental result of the collection efficiency of the axial flow cyclone with the fixed guide vanes is lower than that with the tangential inlet pipe to the cyclone body due to the weak angular momentum transfer given by flowing through the guide vanes. However, one of the interesting points is the control of the collection efficiency depended on the funnel shaped exit pipes. The collection efficiencies for these funnel shaped exit pipes are depended on the Froude number. Then, in this paper, the experimental results of the pressure drop and also the collection efficiency using the fly-ash particles and also the comparison of the calculated results of the collection efficiency with the experimental results are described i~ detail.

关键词： Axial flow cyclone funnel shaped exit pipe fixed guide vanes pressure drop collection efficiency,Froude number cut-Size

IoT-based Smart and Complex Systems：A Guest Editorial Report

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IEEE/CAA Journal of Automatica Sinica 2018年第1期5卷 69-73页

作者： Naiqi Wu Zhiwu Li Kamel Barkaoui Xiaoou Li tadahiko Murata MengChu Zhou Institute of Systems Engineering Macao University of Science and Technology Macao 999078 China School of Electro-Mechanical Engineering Xidian University Xi'an 710071 China Conservatoire national des arts et mtiers Professeur des universit6s EPN5 Informatique Lab. Cedric-Vespa 2 rue Cont6 75141 Pads Cedex 03 France CINVESTAV-IPN Mexico Kansai University Japan Department of Electrical and Computer Engineering New Jersey Institute of Technology Newark NJ 07102-1982 USA IEEE

THE Industrial Revolution starting from about 1760 and ending at around 1840 has been viewed as the first Industrial *** features with the replacement of human and animal muscle power with steam and mechanical *** inc... 详细信息

关键词： In IoT-based Smart and Complex Systems:A Guest Editorial Report