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Brazilian Power Electronics Conference

作者： Cursino B. Jacobina Isaac S. de Freitas Lilian G. de Azevedo Mauricio B. R. Correa Post-Graduate Program in Electrical Engineering - PPgEE - COPELE Electrical Engineering Department - DEE - Federal University of Campina Grande - UFCG Alternative and Renewable Energy Center - CEAR Electrical Engineering Department - DEE - Federal University of Paraiba - UFPB

ISBN: (纸本)9781479902712

This paper presents two ac machine drive systems based on three-phase to five-phase ac-ac converters and open-windings five-phase machine. The drive systems are suitable to applications in which high power, performance and reliability are required using low power and voltage switches and low dc-link capacitor voltages. The configuration I employs an input transformer with two secondary taps at the grid side, two three-phase three-leg converters and one ten-leg converter (totalling sixteen legs). The configuration II employs a low-power series transformer at the grid side, two three-phase three-leg converters, and one ten-leg converter. Both configurations permit to reduce the power and voltage ratings of power switches and also the dc-link capacitor size. The paper presents the comprehensive models of the proposed systems, modulation strategies and a general comparison with conventional configuration. Simulated and experimental results are presented.

关键词： Ac-Ac Converter Five-phase Machine Motor Drive Open-end windings Power Converter

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Deformation of porous, nanostructured silver at room temperature and 150C°

Deformation of porous, nanostructured silver at room tempera...

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2012 MRS Fall Meeting

作者： Noiseau, Guillaume Becker, Michael F. Keto, John W. Kovar, Desiderio Materials Science and Engineering Graduate Program University of Texas at Austin Austin TX 78712-1591 United States Department of Electrical and Computer Engineering University of Texas Austin TX United States Department of Physics University of Texas Austin TX United States Department of Mechanical Engineering University of Texas Austin TX United States

ISBN: (纸本)9781632661067

Porous, nanostructured silver samples were produced using a direct-write method where a nanoparticle aerosol consisting of particles with a mean size of approximately 5 nm were accelerated to speeds of approximately 1000 m/sec and impacted onto a translating substrate [1]. The impacting particles have sufficient energy to stick to the substrate, allowing patterned thick films to be directly written from the aerosol without a mask. Unlike other low temperature processing routes for achieving patterned films, no organics are added that can interfere with post-deposition processing. Typical films are 5-100 μm thick, up to several centimeters long, and have an as-deposited relative densities as high as 70% of bulk Ag. Compression tests were carried out in steps at room temperature and at 150°C under constant displacement rates. Local strain and densification were measured by optical profilometry between each compression step. The results can be used as a starting point to better understand the mechanisms that govern plasticity, creep, and sintering in nanostructured, porous silver at low processing temperatures. © 2013 Materials Research Society.

关键词： Room temperature

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Vibration Characterization Using Gaussian Laser Beam

Vibration Characterization Using Gaussian Laser Beam

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International Conference on Modeling, Simulation and Applied Optimization

作者： Naveed A. Abbasi Taha Landolsi Rached Dhaouadi Graduate Program of Mechatronics Engineering American University of Sharjah Department of Computer Engineering American University of Sharjah Department of Electrical Engineering American University of Sharjah

ISBN: (纸本)9781467358125

The objective of this research is to present a neural network based optical vibration sensor using a quad-cell photo-detector array. The proposed system uses a He-Ne laser source whose Gaussian beam impinges on the photo-detector array. The optical power distribution from the photo-detectors is fed to vibration monitoring system which maps the power distribution to the x-y position of the laser beam center. The vibration monitoring system uses artificial neural networks for function approximation to yield the correct mapping and estimate the x-y positions of the laser beam center which are then used for vibration characterization. An experimental setup of the system is developed and then trained using neural networks. The results obtained show the effectiveness of neural networks to estimate the vibration frequency and magnitude of a vibrating system.

关键词： Vibration monitoring Neural network Optical sensor Quad-cell photo detector array

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Simplifying complexity: Modeling the process of collaboration between artists and scientists 13

Simplifying complexity: Modeling the process of collaboratio...

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31st ACM International Conference on Design of Communication, SIGDOC 2013

作者： McDougall, Zoe Fels, Sidney Lopes, Dominic O'Brien, Heather L. Interdisciplinary Studies Graduate Program University of British Columbia Vancouver BC Canada Department of Electrical and Computer Engineering University of British Columbia Vancouver BC Canada Department of Philosophy University of British Columbia Vancouver BC Canada The iSchool University of British Columbia Vancouver BC Canada

ISBN: (纸本)9781450321310

This paper presents a modal model to describe and facilitate communication design in collaborative settings. This model was conceived of as a tool for understanding the nature of collaboration between artists and scientists in an interdisciplinary case study, but can be used cross-disciplinarily and ultimately prescriptively. The model may reveal shifting patterns of interaction between collaborators over time and through multiple processes. Patterns may be revealed in setting and attaining benchmark goals as well as in general group communication. Different collaborative modes (ontological relationships between collaborators) and modes of being (phenomenological relationship between collaborators) form the basis for sixty collaborative possibilities with two or more collaborators. © 2013 ACM.

关键词： communication collaboration models charles s. peirce

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Power hardware-in-the-loop (PHIL) based on FPGA

Power hardware-in-the-loop (PHIL) based on FPGA

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Brazilian Power Electronics Conference, COBEP

作者： Camila S. Gehrke Alexandre C. Oliveira Antonio Marcus N. Lima Italo Roger F. M. P. da Silva Universidade Federal de Campina Grande Campina Grande PB BR Department of Electrical Engineering (DEE) Federal University of Campina Grande (UFCG) Campina Grande PB Brazil Post-graduate Program in Electrical Engineering - PPgEE/COPELE

Nowadays, to improve power quality and power demand, several studies point to the use of Active Power Line Conditioners (APLCs) and Distributed Generation (DG), both based on power electronic devices. Considering various distributed power devices with cooperative operation, the strategies evaluation to compensate harmonics and correct power factor (PF) in Electric Power System (EPS) is only possible to be investigated by simulation. In this work, it is proposed a Power Hardware-in-the-loop (PHIL) system for testing the APLCs operation. The proposed PHIL system can evaluate the performance of the APLC control strategies and EPS dynamic response under APLC operation. Furthermore, the same platform can be used to integrating DGs with the EPS as it also uses power electronic devices.

关键词： Field programmable gate arrays Harmonic analysis Digital signal processing Power harmonic filters Power quality

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Analysis of Needle-Tissue Friction during Vibration-Assisted Needle Insertion

Analysis of Needle-Tissue Friction during Vibration-Assisted...

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IEEE/RSJ International Conference on Intelligent Robots and Systems

作者： Iman Khalaji Mostafa Hadavand Ali Asadian Rajni V. Patel Michael D. Naish Canadian Surgical Technologies and Advanced Robotics (CSTAR) Lawson Health Research Institute London Canada Biomedical Engineering Graduate Program Western University Department of Electrical and Computer Engineering Western University Department of Electrical and Computer Engineering and the Department of Surgery Western University Department of Mechanical and Materials Engineering and the Department of Electrical and Computer Engineering Western University

ISBN: (纸本)9781467363563

In this paper, a vibration-assisted needle insertion technique has been proposed in order to reduce needle-tissue friction. The LuGre friction model was employed as a basis for the current study and the model was extended and analyzed to include the impact of high-frequency vibration on translational friction. Experiments were conducted to evaluate the role of insertion speed as well as vibration frequency on frictional effects. In the experiments conducted, an 18 GA brachytherapy needle was vibrated and inserted into an ex-vivo soft tissue sample using a pair of amplified piezoelectric actuators. Analysis demonstrates that the translational friction can be reduced by introducing a vibratory low-amplitude motion onto a regular insertion profile, which is usually performed at a constant rate.

关键词： friction high frequency vibration LuGre friction Vibrational frequencies Insertion Mutation Pairing

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Evaluating geographic topological vulnerabilities

Evaluating geographic topological vulnerabilities

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International Conference on Ultra Modern Telecommunications and Workshops (ICUMT)

作者： Xuelian Long David Tipper Teresa Gomes Graduate Telecommunications and Networking Program University of Pittsburgh Pittsburgh PA Department of Electrical and Computer Engineering University of Coimbra / INESC Coimbra Coimbra Portugal

Measuring the survivability of core backbone communication networks to geographic correlated failures is important in network analysis and design. Different measures of network survivability have been used in the literature, for example, Algebraic Connectivity, Network Criticality, Average Shortest Path, Network Diameter, Node Degree and Node Strength. This paper proposes a new performance measure Weighted Spectrum to evaluate network survivability regarding geographic correlated failures. Further we conduct a comparative analysis by finding the most vulnerable geographic cuts or nodes in the network though solving an optimization problem to determine the cut with the largest impact for each measure. Numerical results on several sample network topologies show that the worst-case geographic cuts depend on the measure used in an unweighted graph. The proposed Weighted Spectrum measure is shown to be more versatile than other measures in unweighted and weighted graphs.

关键词： Network topology Topology Weight measurement Laplace equations Conferences Reliability engineering

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Deformation of Porous, Nanostructured Silver at Room Temperature and 150 °C

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MRS Online Proceedings Library 2013年第1期1513卷 1-6页

作者： Noiseau, Guillaume Becker, Michael F. Keto, John W. Kovar, Desiderio Materials Science and Engineering Graduate Program The University of Texas at Austin Austin USA Department of Electrical and Computer Engineering The University of Texas Austin USA Department of Physics The University of Texas Austin USA Department of Mechanical Engineering The University of Texas Austin USA

Porous, nanostructured silver samples were produced using a direct-write method where a nanoparticle aerosol consisting of particles with a mean size of approximately 5 nm were accelerated to speeds of approximately 1000 m/sec and impacted onto a translating substrate [1]. The impacting particles have sufficient energy to stick to the substrate, allowing patterned thick films to be directly written from the aerosol without a mask. Unlike other low temperature processing routes for achieving patterned films, no organics are added that can interfere with postdeposition processing. Typical films are 5- 100 μm thick, up to several centimeters long, and have an as-deposited relative densities as high as 70% of bulk Ag. Compression tests were carried out in steps at room temperature and at 150°C under constant displacement rates. Local strain and densification were measured by optical profilometry between each compression step. The results can be used as a starting point to better understand the mechanisms that govern plasticity, creep, and sintering in nanostructured, porous silver at low processing temperatures.

关键词： Ag densification nanoscale

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Single-phase to three-phase induction generation system with two parallel single-phase half-bridge converters

Single-phase to three-phase induction generation system with...

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Brazilian Power Electronics Conference, COBEP

作者： Nady Rocha Ely C. de Menezes Ítalo A. Cavalcanti de Oliveira Cursino B. Jacobina Electrical Engineering Department (DEE) Federal University of Paraíba (UFPB) Cidade Universitária - João Pessoa PB Brazil Post-Graduate Program in Electrical Engineering - PPgEE - COPELE Federal University of Campina Grande (UFCG) Campina Grande PB Brazil

This paper presents a generation system based on the induction generator for wind energy application. The induction generator is connected to single-phase grid through an ac-dc-ac single-phase to three-phase converter. The single-phase converter is composed of two parallel single-phase half-bridge converters. Suitable modelling, including the circulation current, and control strategy are developed. The control of generator is based on the field oriented control. A pulse width-modulation (PWM) technique using a single and double carriers PWM is presented. Proposed topology permits to improve the harmonic distortion. Beside, it can reduce the power losses in the converter. Finally, simulation and experimental results are presented.

关键词： Pulse width modulation Topology Estimation Induction generators Inductance Harmonic distortion

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Group Method of Data Handling for Modeling Magnetorheological Dampers

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Intelligent Control and Automation 2013年第1期4卷 70-79页

作者： Khaled Assaleh Tamer Shanableh Yasmin Abu Kheil Department of Computer Science and Engineering American University of Sharjah Sharjah United Arab Emirates Department of Electrical Engineering American University of Sharjah Sharjah United Arab Emirates Mechatronics Graduate Program American University of Sharjah Sharjah United Arab Emirates

This paper proposes the use of Group Method of Data Handling (GMDH) technique for modeling Magneto-Rheological (MR) dampers in the context of system identification. GMDH is a multilayer network of quadratic neurons that offers an effective solution to modeling non-linear systems. As such, we propose the use of GMDH to approximate the forward and inverse dynamic behaviors of MR dampers. We also introduce two enhanced GMDH-based solutions. Firstly, a two-tier architecture is proposed whereby an enhanced GMD model is generated by the aid of a feedback scheme. Secondly, stepwise regression is used as a feature selection method prior to GMDH modeling. The proposed enhancements to GMDH are found to offer improved prediction results in terms of reducing the root-mean-squared error by around 40%.

关键词： System Identification Magneto-Rheological Dampers Group Method of Data Handling Polynomial Classifier

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