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Hiroshi.Hattori,Mutsuo Nakaoka,Kenji.Sakamoto 전력전자학회 1998 ICPE(ISPE)논문집 Vol.- No.-
In this paper, a prototype of the auxiliary resonant commutated snubber circuit (ARCS) with a high frequency transformer power regeneration loop is described for voltage source type sinewave inverter system. This is a new soft switching topology developed for three phase voltage source soft-switching inverter, active power filter and reactive power compensator has significant advantage of current rating reduction for auxiliary active switching devices. In addition, this paper presents a novel prototype of voltage-source soft switching space vector-modulated inverter with ARCS mentioned above, which is more suitable and acceptable for high-power utility interactive power conditioning, along with a digital control scheme. The steady-state operating analysis of ARCS has the remarkable features and the practical design procedure of this resonant snubber are illustrated on the basis of computer simulation analysis. The operating performance evaluations in the steady-state of this three phase voltage source soft switching inverter are discussed and compared with the three phase voltage source hard switching inverter.
Hiroshi Ochi,Yoshitaka Watanabe,Takuya Shimura,Takehito Hattori 제어로봇시스템학회 2009 제어로봇시스템학회 국제학술대회 논문집 Vol.2009 No.8
To achieve high-speed acoustic data transmission, the use of a frequency band of 80 ± 20 kHz is being considered. However, the absorption attenuation coefficient in these frequencies only has empirical formula. Therefore,the absorption attenuation was measured using the frequency of 60 to 100 kHz within the propagation distance of 530 to 700 m at approximately 1,000 m depth. The transmission signal wave form was measured with conductivity,temperature, and depth (CTD) data. From these measured data, the absorption attenuation coefficient was calculatedusing several empirical equations. Calculated value of absorption attenuation coefficients by using measured signal were compared with calculated value by several empirical equations. As a result, a corresponding comparatively good for the empirical formula of Francois and Garrison.
Prediction of Wear Depth Distribution by Slurry on a Pump Impeller
Sugiyama, Kenichi,Nagasaka, Hiroshi,Enomoto, Takeshi,Hattori, Shuji Korean Society for Fluid machinery 2009 International journal of fluid machinery and syste Vol.2 No.1
Slurry wear with sand particles in rivers is a serious problem for pump operation. Therefore, a technique to predict wear volume loss is required for selecting wear resistant materials and determining specifications for the maintenance period. This paper reports a method for predicting the wear depth distribution on the blade of an impeller. Slurry wear tests of an aluminum pump impeller were conducted. Prediction results of wear depth distribution approximately correspond with the results of slurry wear tests. This technique is useful for industrial application.
Structural monitoring of movable bridge mechanical components for maintenance decision-making
Gul, Mustafa,Dumlupinar, Taha,Hattori, Hiroshi,Catbas, Necati Techno-Press 2014 Structural monitoring and maintenance Vol.1 No.3
This paper presents a unique study of Structural Health Monitoring (SHM) for the maintenance decision making about a real life movable bridge. The mechanical components of movable bridges are maintained on a scheduled basis. However, it is desired to have a condition-based maintenance by taking advantage of SHM. The main objective is to track the operation of a gearbox and a rack-pinion/open gear assembly, which are critical parts of bascule type movable bridges. Maintenance needs that may lead to major damage to these components needs to be identified and diagnosed timely since an early detection of faults may help avoid unexpected bridge closures or costly repairs. The fault prediction of the gearbox and rack-pinion/open gear is carried out using two types of Artificial Neural Networks (ANNs): 1) Multi-Layer Perceptron Neural Networks (MLP-NNs) and 2) Fuzzy Neural Networks (FNNs). Monitoring data is collected during regular opening and closing of the bridge as well as during artificially induced reversible damage conditions. Several statistical parameters are extracted from the time-domain vibration signals as characteristic features to be fed to the ANNs for constructing the MLP-NNs and FNNs independently. The required training and testing sets are obtained by processing the acceleration data for both damaged and undamaged condition of the aforementioned mechanical components. The performances of the developed ANNs are first evaluated using unseen test sets. Second, the selected networks are used for long-term condition evaluation of the rack-pinion/open gear of the movable bridge. It is shown that the vibration monitoring data with selected statistical parameters and particular network architectures give successful results to predict the undamaged and damaged condition of the bridge. It is also observed that the MLP-NNs performed better than the FNNs in the presented case. The successful results indicate that ANNs are promising tools for maintenance monitoring of movable bridge components and it is also shown that the ANN results can be employed in simple approach for day-to-day operation and maintenance of movable bridges.
Yuki Kato,Joverienne Chavez,Shin Yamada,Soichi Hattori,Shuzo Takazawa,Hiroshi Ohuchi 대한슬관절학회 2019 대한슬관절학회지 Vol.31 No.2
Purpose: This study aimed to investigate anterior knee symptoms in patients who underwent anterior cruciate ligament (ACL) reconstruction using bonepatellar tendonbone (BPTB) graft followed by implantation of a betatricalcium phosphate (βTCP) block as a bone void filler.Materials and Methods: We retrospectively reviewed 84 cases of synthetic bone grafting using a βTCP block for the patellar bone defect in ACL reconstruction with a BPTB autograft. Computed tomography of the operated knee was performed immediately after the surgery to evaluate whether the grafted βTCP block protruded forward from the anterior surface of the patella. On the basis of the results, the cases were divided into a protrusion group (n=31) and a nonprotrusion group (n=53). Anterior knee symptoms at 12 months postoperatively and absorption of the grafted βTCP block were compared between the two groups.Results: Except for patellofemoral crepitus, there was no significant difference in anterior knee symptoms between the two groups (p>0.05). The incidence of patellofemoral crepitus was significantly lower in the protrusion group than in the nonprotrusion group (p=0.027). The groups showed no significant difference in βTCP absorption.Conclusions: The present study demonstrated that the protrusion of βTCP that was used as a bone void filler had no adverse effects.
Miho Ota,Junko Matsuo,Noriko Sato,Toshiya Teraishi,Hiroaki Hori,Kotaro Hattori,Yoko Kamio,Norihide Maikusa,Hiroshi Matsuda,Hiroshi Kunugi 대한신경정신의학회 2018 PSYCHIATRY INVESTIGATION Vol.15 No.10
Objective: Autistic spectrum traits are postulated to lie on a continuum that extends between individuals with autism and individuals with typical development. The present study was carried out to investigate functional and network abnormalities associated with autistic spectrum trait in healthy male subjects. Methods: Subjects were 41 healthy male subjects who underwent the social responsiveness scale-adult (SRS-A) and magnetic resonance imaging. Results: There was significant positive correlation between the total score of SRS-A and the regional cerebral blood flow (CBF) in posterior cingulate cortex (PCC). Also, there were changes in functional network such as in cingulate corti, insula and fusiform cortex. Further, we also found the significant difference of functional networks between the healthy male subjects with high or low autistic spectrum trait, and these points were congruent with the previous perceptions derived from autistic-spectrum disorders. Conclusion: These findings suggest a biological basis for the autistic spectrum trait and may be useful for the imaging marker of autism symptomatology.
Miho Ota,Junko Matsuo,Noriko Sato,Toshiya Teraishi,Hiroaki Hori,Kotaro Hattori,Yoko Kamio,Norihide Maikusa,Hiroshi Matsuda,Hiroshi Kunugi 대한신경정신의학회 2018 PSYCHIATRY INVESTIGATION Vol.15 No.11
Objective Autistic spectrum traits are postulated to lie on a continuum that extends between individuals with autism and individuals with typical development. The present study was carried out to investigate functional and network abnormalities associated with autistic spectrum trait in healthy male subjects. Methods Subjects were 41 healthy male subjects who underwent the social responsiveness scale-adult (SRS-A) and magnetic resonance imaging. Results There was significant positive correlation between the total score of SRS-A and the regional cerebral blood flow (CBF) in posterior cingulate cortex (PCC). Also, there were changes in functional network such as in cingulate corti, insula and fusiform cortex. Further, we also found the significant difference of functional networks between the healthy male subjects with high or low autistic spectrum trait, and these points were congruent with the previous perceptions derived from autistic-spectrum disorders. Conclusion These findings suggest a biological basis for the autistic spectrum trait and may be useful for the imaging marker of autism symptomatology.