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IEEE Workshop on Advanced Robotics and its Social Impacts, ARSO

作者： Tresna Dewi Naoki Uchiyama Shigenori Sano Electronics Study Program State Polytechnic of Sriwijaya 30139 Palembang Indonesia and the Department of Mechanical Engineering Toyohashi University of Technology 441-8580 Toyohashi Japan Department of Mechanical Engineering Toyohashi University of Technology Toyohashi Japan

One of the crucial features of a service robot is the ability “to see” the environment and a target object for smooth navigation. This paper deals with a mobile robot that recognizes and tracks a moving object attached to a wheelchair in a obstacle existing environment. The experiment was conducted in three scenarios, the first one is that the robot is set to recognize and track a moving object in obstacle free environment, and the second and the third ones are the L-course and the crank course bordered by boxes as the obstacles. The third scenario was conducted five times with five different human-targets. The experimental results show that the proposed method is effective in recognizing and tracking the moving object.

关键词： Mobile robots Cameras Robot vision systems Robot kinematics

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Wall to wall optimal transport 15

Wall to wall optimal transport

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15th European Turbulence Conference, ETC 2015

作者： Doering, Charles R. Souza, Andre N. Chini, Gregory P. Hassanzadeh, Pedram Department of Physics University of Michigan United States Department of Mathematics University of Michigan United States Center for the Study of Complex Systems University of Michigan United States Department of Mechanical Engineering Program in Integrated Applied Mathematics and Center for Fluid Physics University of New Hampshire United States Centre for the Environment Department of Earth and Planetary Sciences Harvard University United States

The calculus of variations is employed to find steady divergence-free velocity fields that maximize transport of a tracer between two parallel walls held at fixed concentration for one of two constraints on flow strength: a fixed value of the kinetic energy or a fixed value of the enstrophy (the mean square rate of strain in this situation). The optimizing flows realize upper limits on convective transport in this scenario. We interpret the results in the context of buoyancy-driven Rayleigh–Bénard convection problems that satisfy the flow intensity constraints, enabling us to investigate how optimal transport scalings compare with upper bounds on Nu expressed as a function of the Rayleigh number Ra. © TU Delft.

关键词： Kinetic energy

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Repowering of a synchronous generation plant by induction generator

Repowering of a synchronous generation plant by induction ge...

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CHILEAN Conference on Electrical, Electronics engineering, Information and Communication Technologies (CHILECON)

作者： Alana S. Magalhaes C. A. Leovir Calebe A. Matias Alan H. F. Silva Elder G. Domingues Aylton. J. Alves Wesley P. Calixto Program in Electronic Systems and Automation University of Brasilia (UnB) Brasília Brazil Experimental and Technological Research and Study Group (NExT) Federal Institute of Goias (IFG) Goiânia Brazil School of Electrical Mechanical and Computer Engineering Federal University of Gouias (UFG) Goiânia Brazil

ISBN: (纸本)9781467387576

This work proposes itself through mathematical modeling, simulating the electrical interactions between two electrical generators, an induction generator and a synchronous generator connected to a common bus in steady state, subject to non-linear load. By comparing the modeling of the two machines, we can see that the induction generator will present best way for the harmonic currents flowing in common bus. Experimental tests have confirmed the results of comparative modeling of the electric generators. It was evident that the induction generator, in addition to increasing the active power to the electrical system, could reduce current harmonics components present at the connection point improving the voltage profile in the network.

关键词： Induction generators Harmonic analysis Synchronous generators Power system harmonics Reactive power

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Time-stepping approach for solving upper-bound problems: Application to two-dimensional Rayleigh-Bénard convection

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Physical Review E 2015年第4期92卷 043012-043012页

作者： Baole Wen Gregory P. Chini Rich R. Kerswell Charles R. Doering Program in Integrated Applied Mathematics University of New Hampshire Durham New Hampshire 03824 USA Center for Fluid Physics University of New Hampshire Durham New Hampshire 03824 USA The Institute for Computational Engineering and Sciences The University of Texas at Austin Austin Texas 78712 USA Department of Mechanical Engineering University of New Hampshire Durham New Hampshire 03824 USA School of Mathematics University of Bristol University Walk Bristol BS8 1TW United Kingdom Department of Physics University of Michigan Ann Arbor Michigan 48109-1040 USA Department of Mathematics University of Michigan Ann Arbor Michigan 48109-1043 USA Center for the Study of Complex Systems University of Michigan Ann Arbor Michigan 48109-1107 USA

An alternative computational procedure for numerically solving a class of variational problems arising from rigorous upper-bound analysis of forced-dissipative infinite-dimensional nonlinear dynamical systems, including the Navier-Stokes and Oberbeck-Boussinesq equations, is analyzed and applied to Rayleigh-Bénard convection. A proof that the only steady state to which this numerical algorithm can converge is the required global optimal of the relevant variational problem is given for three canonical flow configurations. In contrast with most other numerical schemes for computing the optimal bounds on transported quantities (e.g., heat or momentum) within the “background field” variational framework, which employ variants of Newton's method and hence require very accurate initial iterates, the new computational method is easy to implement and, crucially, does not require numerical continuation. The algorithm is used to determine the optimal background-method bound on the heat transport enhancement factor, i.e., the Nusselt number (Nu), as a function of the Rayleigh number (Ra), Prandtl number (Pr), and domain aspect ratio L in two-dimensional Rayleigh-Bénard convection between stress-free isothermal boundaries (Rayleigh's original 1916 model of convection). The result of the computation is significant because analyses, laboratory experiments, and numerical simulations have suggested a range of exponents α and β in the presumed Nu∼PrαRaβ scaling relation. The computations clearly show that for Ra≤1010 at fixed L=22,Nu≤0.106Pr0Ra5/12, which indicates that molecular transport cannot generally be neglected in the “ultimate” high-Ra regime.

关键词： RAYLEIGH-Benard convection RESEARCH BOUNDS (Mathematics) CONVECTIVE flow (Fluid dynamics) NATURAL heat convection NUSSELT number

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Simple obstacle avoidance for a mobile robot moving through via points

Simple obstacle avoidance for a mobile robot moving through ...

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IEEE/SICE International Symposium on System Integration

作者： Tresna Dewi Naoki Uchiyama Shigenori Sano Electronic Engineering Study Program of State Polytechnic Sriwijaya Palembang Indonesia Department of Mechanical Engineering Toyohashi University of Technology Toyohashi Japan

This study presents simple obstacle avoidance of a mobile robot that moves through via points in a dynamic environment in which obstacles move. This proposed system consists of two controllers, a reference controller and a PI-controller. The reference controller generates a robot motion reference trajectory in reaching goals and avoiding obstacles by referring sensor information in real time trajectory and the PI-controller moves robot to follow the reference trajectory. Computer simulation was performed to test the effectiveness of proposed method and then extended to experimental tests.

关键词： Robot sensing systems Mobile robots Collision avoidance Trajectory Force Service robots

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Selective surface functionalization at regions of high local curvature in graphene

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Chemical Communications 2013年第7期49卷 677-679页

作者： Wu, Qingzhi Wu, Yaping Hao, Yufeng Geng, Jianxin Charlton, Matthew Chen, Shanshan Ren, Yujie Ji, Hengxing Li, Huifeng Boukhvalov, Danil W. Piner, Richard D. Bielawski, Christopher W. Ruoff, Rodney S. State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Biomedical Materials and Engineering Center Wuhan University of Technology Wuhan 430070 China Department of Mechanical Engineering Department of Materials Science Department of Engineering Program The University of Texas at Austin Austin TX 78712 1 University Station C2200 United States Department of Chemistry and Biochemistry The University of Texas at Austin Austin TX 78712 1 University Station A1590 United States School of Computational Sciences Korea Institute for Advanced Study Seoul 130-722 South Korea ) School of Chemical and Biological Engineering Seoul National University Seoul 151-742 South Korea

Monolayer graphene was deposited on a Si wafer substrate decorated with SiO2 nanoparticles (NPs) and then exposed to aryl radicals that were generated in situ from their diazonium precursors. Using micro-Raman mapping...

Monolayer graphene was deposited on a Si wafer substrate decorated with SiO₂ nanoparticles (NPs) and then exposed to aryl radicals that were generated in situ from their diazonium precursors. Using micro-Raman mapping, the aryl radicals were found to selectively react with the regions of graphene that covered the NPs. The enhanced chemical reactivity was attributed to the increased strain energy induced by the local mechanical deformation of the graphene. © The Royal Society of Chemistry.

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Application of UPFC to improve the LVRT capability of wind turbine generator

Application of UPFC to improve the LVRT capability of wind t...

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2012 22nd Australasian Universities Power engineering Conference: "Green Smart Grid Systems", AUPEC 2012

作者： Alharbi, Yasser M. Yunus, A. M. Shiddiq Siada, A. Abu Electrical and Computer Engineering Department Curtin University Perth Australia Mechanical Eng. Dept. Energy Conv. Study Program State Polytechnic of Ujung Pandang Makassar Indonesia

ISBN: (纸本)9789791884723

Variable speed wind turbine generators installation has been significantly increased worldwide in the last few years. Voltage sag at the grid side may call for the disconnection of the wind turbine from the grid as under such faults it may not comply with the recent developed grid codes for wind energy conversion systems (WECS). In this paper, a Unified Power Flow Controller (UPFC) is applied to improve the low voltage ride through (LVRT) capability of doubly fed induction generator (DFIG)-based WECS during voltage sag at the grid side. Simulation is carried out using MATLAB/Simulink software. Results show that UPFC can significantly improve the LVRT capability of DFIG-based WECS and hence maintaining wind turbine connection to the grid during certain levels of voltage sag at the grid side. © 2012 Institut Teknologi Sepulul.

关键词： Wind Turbine Generators

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Impact of intermittent misfire and fire-through on the performance of full converter based WECS

Impact of intermittent misfire and fire-through on the perfo...

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Australasian Universities Power engineering Conference, AUPEC

作者： A. M. Shiddiq Yunus M. A. S. Masoum A. Abu Siada Mechanical Engineering Department Energy Conv. Study Program State of Polytechnic Ujung Pandang Makassar Indonesia Electrical and Computer Engineering Department Curtin University of Technology Perth Australia

The integration of wind turbines into modern power grids has significantly increased during the last decade. The wind turbine equipped with full converter based wind energy Conversion System (FCWECS) represented about 20.3% of the worldwide total wind capacity in 2003. Since FCWECS is equipped with a voltage source inverter (VSI), it is vulnerable that misfire and fire-through may occur within the VSI switches. In this paper, impact of these switching malfunctions on FCWECS performance is investigated and discussed. Detailed simulations of the system under study are carried out using Matlab/Simulink to highlight the influence of these converter internal faults on PCC voltage, DC link voltage and shaft speed, as well as generator active and reactive power. Furthermore, compliance of the FCWECS with Spain fault ride through (FRT) grid codes is also investigated.

关键词： Inverters Wind turbines Generators Educational institutions Reactive power Voltage fluctuations Insulated gate bipolar transistors

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Application of UPFC to improve the LVRT capability of wind turbine generator

Application of UPFC to improve the LVRT capability of wind t...

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Australasian Universities Power engineering Conference, AUPEC

作者： Yasser M. Alharbi A. M. Shiddiq Yunus A. Abu Siada Electrical and Computer Engineering Department Curtin University of Technology Perth Australia Mechanical Engineering Department Energy Conv. Study Program State of Polytechnic Ujung Pandang Makassar Indonesia

关键词： Voltage fluctuations Wind turbines Reactive power Voltage control Power system stability Generators Wind energy

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Impact of DC-Link Fault on the Dynamic Performance of DFIG

Impact of DC-Link Fault on the Dynamic Performance of DFIG

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IEEE Power and Energy Society General Meeting

作者： A. M. Shiddiq Yunus A. Abu-Siada Mohammad A. S. Masoum the Department of Mechanical Engineering Energy Conversion Study Program State Polytechnic of Ujung Pandang Perintis Kemerdekaan KM. 10 Makassar 90215 Indonesia the Department of Electrical and Computer Engineering Curtin University Perth WA 6845 Australi

ISBN: (纸本)9781467327275

The number of doubly fed induction generators (DFIG) connected to the existing network has increased significantly worldwide during the last two decades. This triggers off manufactures to improve the performance of DFIG through robust and reliable design. The stator in DFIG is directly connected to the grid whereas the rotor is interfaced to the grid through two voltage source converters;rotor side converter (RSC) and grid side converter (GSC), which are considered as the crux of the DFIG system. The converter stations determine the ability of wind turbine to operate optimally during wind speed fluctuation and it can provide reactive power support to the grid during grid disturbance events. The DC capacitor link between the two converters allows optimum and smooth power exchange between DFIG and the grid. Therefore, any faults within the DC link will affect the overall performance of the DFIG. This paper investigates the impact of open circuit and short circuit faults in the DC link capacitor on the dynamic performance of the DFIG. The compliance of the wind energy conversion (WEC) system with different grid codes such as those of Denmark, Spain, Nordic and Sweden under such faults is also investigated.

关键词： Index Terms-DFIG Grid side converter Rotor side converter Fault ride through dynamic characteristics DC link dc-link capacitor grids Converters Grid computing faults Circuit faults power markets Crux hydraulic props Manufactured products voltage source Stators Grid

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