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GPGPU-parallelised hybrid finite-discrete element modelling of rock chipping and fragmentation process in mechanical cutting

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Journal of Rock Mechanics and Geotechnical Engineering 2020年第2期12卷 310-325页

作者： Mojtaba Mohammadnejad Sevda Dehkhoda Daisuke fukuda Hongyuan Liu Andrew Chan School of Engineering College of Science and EngineeringUniversity of TasmaniaHobartTAS7001Australia CSIRO Minerals Resources Business UnitQCAT 1 Technology CourtPullenvaleQLD4069Australia Hatch BrisbaneQLD4000Australia Division of Sustainable Resources Engineering Faculty of EngineeringHokkaido UniversityHokkaidoJapan

Mechanical cutting provides one of the most flexible and environmentally friendly excavation *** has attracted numerous efforts to model the rock chipping and fragmentation process,especially using the explicit finite element method(FEM) and bonded particle model(BPM),in order to improve cutting *** study investigates the application of a general-purpose graphic-processing-unit parallelised hybrid finite-discrete element method(FDEM) which enjoys the advantages of both explicit FEM and BPM,in modelling the rock chipping and fragmentation process in the rock scratch test of mechanical rock *** input parameters of FDEM are determined through a calibration procedure of modelling conventional Brazilian tensile and uniaxial compressive tests of limestone,A series of scratch tests with various cutting velocities,cutter rake angles and cutting depths is then modelled using FDEM with calibrated input parameters.A few cycles of cutter/rock interactions,including their engagement and detachment process,are modelled for each case,which is conducted for the first time to the best knowledge of the authors,thanks to the general purpose graphic processing units(GPGPU) *** failure mechanism,cutting force,chipping morphology and effect of various factors on them are discussed on the basis of the modelled ***,it is concluded that GPGPU-parallelised FDEM provides a powerful tool to further study rock cutting and improve cutting efficiencies since it can explicitly capture different fracture mechanisms contributing to the rock chipping as well as chip formation and the separation process in mechanical ***,it is concluded that chipping is mostly owed to the mix-mode Ⅰ-Ⅱ fracture in all cases although mode Ⅱ cracks and mode Ⅰ cracks are the dominant failures in rock cutting with shallow and deep cutting depths,*** chip morphology is found to be a function of cutter velocdty,cutting depth and cutter rake angl

关键词： Numerical simulation Finite-discrete element method(FDEM) Rock cutting Chipping Cracking

Improvement of registration accuracy of a handheld augmented reality system for urban landscape simulation

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Frontiers of Architectural Research 2014年第4期3卷 386-397页

作者： Tomohiro fukuda Tian Zhang Nobuyoshi Yabuki Graduate School of Engineering Osaka University Suita Osaka 565-0871 Japan Nikken Space Design Ltd. Bunkyo-ku Tokyo Japan

The need for visual landscape assessment in large-scale projects for the evaluation of the effects of a particular project on the surrounding landscape has grown in recent years. Augmented reality （AR） has been considered for use as a landscape simulation system in which a landscape assessment object created by 3D models is included in the present surroundings. With the use of this system, the time and the cost needed to perform a 3DCG modeling of present surroundings, which is a major issue in virtual reality, are drastically reduced. This research presents the development of a 3D maporiented handheld AR system that achieves geometric consistency using a 3D map to obtain position data instead of GPS, which has tow position information accuracy, particularly in urban areas. The new system also features a gyroscope sensor to obtain posture data and a video camera to capture live video of the present surroundings. All these components are mounted in a smartphone and can be used for urban landscape assessment. Registration accuracy is evaluated to simulate an urban landscape from a short- to a long-range scale. The latter involves a distance of approximately 2000 m. The developed AR system enables users to simulate a Landscape from multiple and longdistance viewpoints simultaneously and to walk around the viewpoint fields using only a smartphone. This result is the tolerance level of Landscape assessment. In conclusion, the proposed method is evaluated as feasible and effective.

关键词： Landscape simulation Augmented reality Handheld device Registration accuracy Assessment

A synchronous distributed cloud-based virtual reality meeting system for architectural and urban design

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Frontiers of Architectural Research 2014年第4期3卷 348-357页

作者： Lei Sun Tomohiro fukuda Bernd Resch School ol Engineering Osaka University Suito Osaka S 4521 Japan Institute of Geography University of Heidelberg Heidelberg D 69120 Germany Harvard University Cambridge MA USA

In the spatial design fields such as architectural design and urban design, a consensus-building process among a variety of stakeholders like project executors, architects, residents, users, and general citizens is required. New technological developments such as cloud computing and Virtual Design Studios （VDS） enable the creation of virtual meeting systems. This paper proposes an approach towards a synchronous distributed design meeting system. In this paper, in addition to sharing a 3D virtual space for a synchronous distributed type design meeting, we developed a prototype system that enables participants to sketch or make annotations and have discussions as well as add viewpoints to them. We applied these functions to evaluate an architectural design and urban landscape examination. In conclusion, the proposed method was evaluated as being effective and feasible. Yet, it shows a few shortcomings including the fact that simultaneous operation is limited to one client, and more arbitrary shapes should be supported in future versions of the application.

关键词： Spatial design meeting Distributed synchronization Cloud computing Annotation Discussion board

Effects of Working Fluid,Tubeside Enhancement and Bundle Depth on the Optimized Fin Geometry of a Horizontal Condenser Tube

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Journal of Thermal Science 1992年第2期1卷 123-129页

作者： H.Honda T.fukuda InstituteofAdvancedMaterialStudy KyushyuUniversityKasugaFukuoka818Japan InstituteofAdvancedMateria

A theoretical study has been made to optimize the fin geometry of a horizontal finned tube which is to be used for condensers that handle the vapor load of a liquid phase change cooling *** numerical calcu- lations of the vapor to coolant heat transfer have been performed for parametric values of fin height,fin spacing, vertical bundle depth and tubeside heat transfer *** dielectric fluids (R-113,FC-72,and FC-87) at atmospheric pressure were selected as the working *** a single tube with optimized fin geometry,the average heat flux increased in the order of FC-87,R-113 and *** the optimum fin height and optimum fin spacing increased with increasing vertical bundle depth.

关键词： finned condenser tube optimized fin geometry dielectric fluids physical model

Construction of Multilayer Porous Scaffold Based on Magnetically Guided Assembly of Microfiber

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Journal of Systems Science & Complexity 2018年第3期31卷 581-595页

作者： LI Xingfu WANG Huaping SHI Qing SUN Tao HUANG Qiang fukuda Toshio Intelligent Robotics Institute School of Mechatronical Engineering Beijing Institute of Technology Beijing 100081 China Key Laboratory of Biomimetic Robots and Systems Ministry of Education Beijing 100816 China Key Laboratory of Intelligent Control and Decision of Complex Systems Beijing 100081 China

This paper proposes a novel method of magnetically guided assembly to construct multi- layer porous scaffold for three-dimensional cell culture by apply magnetic microfibers. Microfibers are composed of biocompatible and biodegradable alginate solution with homogeneous magnetic nanopar- ticles, which are continuously spun from a microfluidic device by precise pressure control of the syringe pump. Magnetic nanoparticles enable the control of magnetic field on microfibers. Meanwhile, mag- netized device combining with a round permanent magnet are utilized to guide the distribution of spouted microfibers. The device is composed by pure iron wire arrays and wax, which stimulates pow- erful magnetic flux density and magnetic field gradients for the capture and assembly of microfibers. Thus, magnetic microfibers are spun on desired places of the magnetized device by motion control of the micromanipulation robot, and precise locations are adjusted by magnetic force couple with the assist of glass micropipette. Afterwards, microfibers are spatially organized by periodic magnetic force and crossed layer-by-layer to form micro-pore structure with both length and width of 650μm. Finally, the authors construct a multilayer microfiber-based scaffold with high porosity to provide a satisfactory environment for long-term cell culture. The experimental results demonstrate the effectiveness of the proposed method.

关键词： Magnetically guided assembly magnetic microfiber magnetized device periodic magneticforce multilayer porous scaffold.

Editorial for the Special Issue on Unmanned Intelligent Cluster

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Engineering 2022年第5期8卷 1-2页

作者： Jun Zhang Toshio fukuda Defu Lin Florian Holzapfel School of Information and Electronics Beijing Institute of TechnologyBeijing 100081China School of Mechatronical Engineering Beijing Institute of TechnologyBeijing 100081China School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China Institute of Flight System Dynamics Technical University of MunichGarching 85748Germany

Recent advances in networked cooperative autonomous sys-tems offer the potential to significantly improve system quality for a wide range of *** in embedded processor,sensor,communication,and networking technology in the last few decades has accelerated interest in networked cooperative autonomous systems,multirobot systems,and distributed sensor networks for applications such as manufacturing,logistics,pro-cess monitoring,enhanced situational awareness,plant safety,inspection,security,and rescue operations.

关键词： robot networks autonomous

Self-interstitials generated on silicon bulk surface

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Progress in Natural Science:Materials International 2011年第1期21卷 17-20页

作者： Yukihiro KATO Ryoji fukuda Yuta TAKENO Toshitada SHIMOZAKI Takahisa OKINO Department of Design Engineering Semiconductor Business DivisionMitsumi Electric Co.LtdAtugi 243-0004Japan Department of Architecture and Mechatronics Faculty of EngineeringOita UniversityOita 870-1192Japan Department of Materials and Technology Kyushu Institute of TechnologyKitakyushu 804Japan

The self-interstitial atoms in silicon generated by the bulk surface oxidation diffuse into the bulk inside and affect the phenomena such as the diffusions and the stacking *** generation rate of self-interstitials(Rgen) depends on theωpower of the oxidation film growth rate dX0/*** physical quantityωis important to understand the material science relevant to self-interstitials in the silicon ***,the conclusiveωvalue is not reported,although variousωvalues to control the generation rate have been *** the present study,the chemical reaction equation is analytically solved,and using the result,the oxidation stacking fault radius(r) is analytically expressed against the oxidation time(t).Comparing the obtained relation of r=r(t) with the experimental results of the stacking faults,the analytical expression of co is determined and the physical meaning ofωis ***,the temperature dependence ofωis also numerically determined.

关键词： silicon self-interstitial vacancy oxide impurity diffusion stacking fault

Acute and delayed psychiatric sequelae among patients hospitalised with COVID-19:a cohort study using LIFE study data

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General Psychiatry 2022年第3期35卷 173-182页

作者： Fumiko Murata Megumi Maeda Chieko Ishiguro Haruhisa fukuda Department of Health Care Administration and Management Kyushu University Graduate School of Medical SciencesFukuokaJapan National Center for Global Health and Medicine ShinjukukuTokyoJapan

Background Characterising the psychiatric sequelae of coronavirus disease 2019(COVID-19)can inform the development of long-term treatment ***,few studies have examined these sequelae at different time points after COVID-19 *** The study aimed to investigate the incidences and risks of acute and delayed psychiatric sequelae in patients hospitalised with COVID-19 in *** This retrospective cohort study was conducted using a database comprising healthcare claims data from public health insurance enrollees residing in a Japanese *** analysed a primary cohort comprising patients hospitalised with COVID-19 between March 2020 and July 2021 and two control cohorts comprising patients hospitalised with influenza or other respiratory tract infections(RTI)during the same *** calculated the incidences of acute(1–3 months after infection)and delayed(4–6 months after infection)psychiatric *** sequelae were identified using diagnosis codes and categorised as mood/anxiety/psychotic disorder,mood disorder,anxiety disorder,psychotic disorder or *** logistic regression models were used to estimate the odds ratios(ORs)of psychiatric sequelae occurrence after COVID-19 infection compared with influenza and other *** The study population with acute psychiatric sequela consisted of 662 patients with COVID-19,644 patients with influenza,and 7369 patients with RTI who could be followed for 3 months;the study population with delayed psychiatric sequelae consisted of 371 patients with COVID-19,546 patients with influenza,and 5397 patients with RTI who could be followed for 6 *** the analysis of acute psychiatric sequelae,COVID-19 had significantly higher odds of mood/anxiety/psychotic disorder(OR:1.39,p=0.026),psychotic disorder(OR:2.13,p<0.001),and insomnia(OR:2.59,p<0.001)than influenza,and significantly higher odds of insomnia(OR:1.44,p=0.002)and significantly lower odds of anxiety disorder(OR:0.56,p<0.

关键词： patients psychiatric sequelae

Learning Rat-Like Behavior for a Small-Scale Biomimetic Robot

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Engineering 2022年第10期17卷 232-243页

作者： Zihang Gao Guanglu Jia Hongzhao Xie Qiang Huang Toshio fukuda Qing Shi Key Laboratory of Biomimetic Robots and Systems(Beijing Institute of Technology) Ministry of EducationBeijing 100081China Intelligent Robotics Institute School of Mechatronical EngineeringBeijing Institute of TechnologyBeijing 100081China Beijing Advanced Innovation Center for Intelligent Robots and Systems Beijing Institute of TechnologyBeijing 100081China

Existing biomimetic robots can perform some basic rat-like movement primitives(MPs)and simple behavior with stiff combinations of these *** mimic typical rat behavior with high similarity,we propose parameterizing the behavior using a probabilistic model and movement ***,an analysis of fifteen 10 min video sequences revealed that an actual rat has six typical behaviors in the open field,and each kind of behavior contains different bio-inspired combinations of eight *** used the softmax classifier to obtain the behavior-movement hierarchical probability ***,we specified the MPs using movement parameters that are static and *** obtained the predominant values of the static and dynamic movement parameters using hierarchical clustering and fuzzy C-means clustering,*** predominant parameters were used for fitting the rat spinal joint trajectory using a second-order Fourier series,and the joint trajectory was generalized using a back propagation neural network with two hidden ***,the hierarchical probability model and the generalized joint trajectory were mapped to the robot as control policy and commands,*** implemented the six typical behaviors on the robot,and the results show high similarity when compared with the behaviors of actual rats.

关键词： Biomimetic Bio-inspired robot Neural network learning system Behavior generation