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Conference on Lasers and Electro-Optics (CLEO)

作者： Hyunyong Choi Vasileios-Marios Gkortsas Franz X. Kartner Laurent Diehl Christine Y. Wang Federico Capasso David Bour Scott Corzine Jintian Zhu Gloria Hofler Theodore B. Norris Center for Ultrafast Optical Science Department of Electrical Engineering and Computer Science University of Michigan Ann Arbor MI USA Research Laboratory of Electronics Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology Cambridge MA USA School of Engineering and Applied Sciences Harvard University Cambridge MA USA Agilent Laboratories Palo Alto CA USA

Ultrafast upconversion is employed to investigate pulse propagation in quantum cascade lasers. The authors have observed advances of the pulse peak to early times, pulse re-shaping, and evidence of a coherent contribu... 详细信息

ISBN: (纸本)9781557528599

关键词： Quantum cascade lasers Resonance Optical pulses Optical propagation Ultrafast optics Optical pulse generation Pulse amplifiers Nonlinear optics Optical distortion Atom optics

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Navigation of an omni-directional mobile robot with active caster wheels

Navigation of an omni-directional mobile robot with active c...

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IEEE International Conference on Robotics and Automation (ICRA)

作者： Eui-jung Jung Ho Yul Lee Jae Hoon Lee Byung-Ju Yi Whee Kuk Kim Shin'ichi Yuta School of Electrical Engineering and Computer Science Hanyang University South Korea Intelligent Systems Research Institute Ubiquitous Functions Research Group AIST Japan Department of Control and Instrumentation Engineering Korea University South Korea Institute of Engineering Mechanics and Systems University of Tsukuba Japan

This work deals with navigation of an omni-directional mobile robot with active caster wheels. Initially, the posture of the omni-directional mobile robot is calculated by using the odometry information. Next, the position accuracy of the mobile robot is measured through comparison of the odometry information and the external sensor measurement. Finally, for successful navigation of the mobile robot, a motion planning algorithm that employs kinematic redundancy resolution method is proposed. Through experiments for multiple obstacles and multiple moving obstacles, the feasibility of the proposed navigation algorithm was verified.

关键词： Navigation Mobile robots Wheels Kinematics computer science Position measurement Roads Robotics and automation USA Councils Motion planning

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Single passband, tunable, photonic microwave filter based on supercontinuum and Hi-Bi fiber interferometric filter

Single passband, tunable, photonic microwave filter based on...

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OptoElectronics and Communications Conference, OECC

作者： Ju Han Lee Woo Jin Jeong Sang Bae Lee You.-Min. Chang School of Electrical and Computer Engineering University of Seoul Seoul South Korea Photonics Research Team Korea Institute of Science and Technology Seoul South Korea Technology Research Center FST Company Hwaseong South Korea

We experimentally demonstrate a novel photonic microwave bandpass filter with capability of frequency tuning and single passband. The filter is constructed by using a CW, depolarized supercontinuum and a multiple segm... 详细信息

关键词： Microwave filters Optical fiber dispersion Optical fiber filters Optical fiber polarization Band pass filters Optical fiber devices Optical fiber networks

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Basic performance of a desktop NC machine tool with compliant motion capability

Basic performance of a desktop NC machine tool with complian...

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IEEE International Conference on Mechatronics and Automation

作者： Fusaomi Nagata Shintaro Tani Takanori Mizobuchi Tetsuo Hase Zenku Haga Masaaki Omoto Keigo Watanabe Maki K. Habib Department of Electronics and Computer Science Tokyo University of Science Sanyo-Onoda Japan Research & Development Center Meiho Company Limited Nogata Japan Department of Advanced Systems Control Engineering Graduate School of Science and Engineering Saga University Saga Japan Mechanical Engineering Department School of Sciences and Engineering American University Cairo Cairo Egypt

In this paper, a new desktop NC machine tool with compliance controllability is presented for finishing metallic molds with small curved surface. The NC machine tool consists of three single-axis robots with high position resolution. A tool attached to the tip of the z-axis has a small ball-end shape. Also, the control system of the NC machine tool is composed of a force feedback loop, position feedback loop and position feedforward loop. The force feedback loop controls the polishing force consisting of tool contact force and kinetic friction force. The position feedback loop controls the position in pick feed direction. Further, the position feedforward loop leads the tool tip along cutter location data. It is expected that the NC machine tool delicately removes surface cusps with under about 0.3 mm height on a mold, and finishes the surface with high quality. In order to first confirm the application limit of a conventional industrial robot to a finishing task, we evaluate the backlash that causes the position inaccuracy at the tip of the abrasive tool, through a simple position/force measurement. Through a similar position/force measurement and a surface following control experiment along a lens mold, the basic position/force controllability of the proposed NC machine tool is demonstrated.

关键词： computer numerical control Force control Force feedback Surface finishing Force measurement controllability Feedback loop Robots Shape control systems

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Neural networks for disturbance and friction compensation in hard disk drives

Neural networks for disturbance and friction compensation in...

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IEEE Conference on Decision and control

作者： Chow Yin Lai Frank L. Lewis V. Venkataramanan Xuemei Ren Shuzhi Sam Ge Thomas Liew Centre for Life Sciences (CeLS) Graduate School for Integrative Sciences and Engineering (NGS) National University of Singapore Singapore Automation and Robotics Research Institute University of Texas Arlington Fort Worth TX USA Data Storage Institute Engineering Agency for Science Technology and Research Singapore Department of Automatic Control Beijing Institute of Technology Beijing China Department of Electrical and Computer Engineering National University of Singapore Singapore

ISBN: (纸本)9781424431236

In this paper, we show that the tracking performance of a hard disk drive actuator can be improved by using two adaptive neural networks, each of which is tailored for a specific task. The first neural network utilizes accelerometer signal to detect external vibrations, and compensates for its effect on hard disk drive position via feedforward action. In particular, no information on the plant, sensor and disturbance dynamics is needed in the design of this neural network disturbance compensator. The second neural network, designed to compensate for the pivot friction, uses a signum activation function to introduce nonlinearities inherent to pivot friction, thus reducing the neural network¿s burden of expectation. The stability of the proposed scheme is analyzed by the Lyapunov criterion. Simulation results show that the tracking performance of the hard disk drives can be improved significantly with the use of both neural networks compared to the case without compensation, or when only one of the networks is activated.

关键词： Neural networks Friction Hard disks Actuators Adaptive systems Feedforward neural networks Accelerometers Signal detection Stability analysis Stability criteria

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Multiscale simulations combined with experimental study of barium/strontium ferrate/cobaltate (BSCF) as a promising material for solid oxide fuel cell (SOFC) 4

Multiscale simulations combined with experimental study of b...

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4th International Conference on Multiscale Materials Modeling, MMM 2008

作者： Ganopadhyay, Shruba Inerbaev, Talgat Masunov, Artëm E. Altilio, Deanna Orlovskaya, Nina Mesit, Jaruwan Guha, Ratan Sleiti, Ahmed Kapat, Jayanta Nanoscience Technology Center University of Central Florida 12424 Research Parkway OrlandoFL32826 United States Department of Chemistry University of Central Florida 12424 Research Parkway OrlandoFL32826 United States Department of Physics University of Central Florida 12424 Research Parkway OrlandoFL32826 United States Department of Mechanical Materials and Aerospace Engineering University of Central Florida 12424 Research Parkway OrlandoFL32826 United States School of Electrical Engineering and Computer Science University of Central Florida 12424 Research Parkway OrlandoFL32826 United States

ISBN: (纸本)9780615247816

Mixed oxides of the general formula ABO3 which crystallize in perovskite structures often have large mobility of the oxygen vacancies and exhibit strong ionic conductivityand used for several practical applications, including Solid Oxide Fuel Cells (SOFC). Barium/Strontium Ferrate/Cobaltate (BSCF) was recently identified as a promising candidate for cathode material in intermediate temperature SOFCs. We apply multiscale technique to determine its vacancy diffusion coefficient. At the small (atomic) scale Density Functional theory (DFT) is used to calculate activation energy barriers for oxygen migration in different local cation distribution. Activation barriers are used in Arrhenius equation to predict the rates for elementary steps in diffusion processes. These rates are then input into Kinetic Monte Carlo (KMC) at large (meso) scale simulations to obtain long time oxygen diffusivities and apparent activation energies. Since KMC method does not need energy evaluations, it is computationally inexpensive and allows treating millions of atoms explicitly. KMC approach can readily describe the macroscopic properties as a function of material morphology. In this contribution we report atomic scale study of BSCF electronic structure using plane wave pseudopotential DFT implemented in Quantum-ESPRESSO. We report cations are completely disordered, while oxygen vacancies exhibit a strong trend to from L-shaped trimers and tetramers, Löwdin population analysis of the spin density indicates that the cobalt cations shows Jahn-Teller distortion of octahedral coordination around Cobalt cations, both theoretically and experimentally and confirmed its intermediate spin state. We compute oxygen vacancy migration activation energy and find it to be in good agreement with experimental data. © MMM 2008. All rights reserved.

关键词： Density functional theory

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Nonlinear Modelling and control of an Autonomous Underwater Vehicle

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IFAC Proceedings Volumes 2008年第1期41卷 1-6页

作者： Wasif Naeem Robert Sutton Intelligent Systems and Control Group School of Electronics Electrical Engineering and Computer Science Queen's University Belfast Belfast BT9 5AH UK (Tel: 44 2890 974066) Marine and Industrial Dynamic Analysis Research Group School of Engineering The University of Plymouth Plymouth PL4 8AA UK

This paper highlights nonlinear modelling and control of the Hammerhead AUV. To model the AUV, a multi-layer perceptron neural network structure has been chosen. Data from actual trials is utilised for training and validating the neural network model. A genetic algorithm (GA) based nonlinear model predictive control (MPC) algorithm is also implemented to the identified model and results are shown for two waypoint following scenarios involving step changes in reference heading. It is demonstrated that the neural network is able to model the system well and the GA-based nonlinear MPC autopilot is quite capable of dealing with nonlinear nonconventional models.

关键词： Modelling neural networks model predictive control genetic algorithms autonomous underwater vehicles

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Orchid: Integrating Schema Mapping and ETL

Orchid: Integrating Schema Mapping and ETL

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International Conference on Data engineering

作者： Stefan Dessloch Mauricio A. Hernandez Ryan Wisnesky Ahmed Radwan Jindan Zhou Department of Computer Science University of Kaiserslautern Kaiserslautern Germany IBM Almaden Research Center San Jose CA US School of Engineering and Applied Sciences Harvard University Cambridge MA USA School of Engineering and Applied Sciences Cambridge MA US department of Electrical and Computer Engineering University of Miami Miami FL US

ISBN: (纸本)9781424418367;1424418364

This paper describes Orchid, a system that converts declarative mapping specifications into data flow specifications (ETL jobs) and vice versa. Orchid provides an abstract operator model that serves as a common model for both transformation paradigms; both mappings and ETL jobs are transformed into instances of this common model. As an additional benefit, instances of this common model can be optimized and deployed into multiple target environments. Orchid is being deployed in FastTrack , a data transformation toolkit in IBM Information Server.

关键词： Data engineering computer science Data flow computing Prototypes Filtering Software tools Data mining Warehousing Programming profession Merging

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Mathematical Analysis of Secondary User Traffic in Cognitive Radio System

Mathematical Analysis of Secondary User Traffic in Cognitive...

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IEEE Conference on Vehicular Technology (VTC)

作者： Junghyun Heo Jungchae Shin Jihee Nam Yutae Lee Joon Goo Park Ho-Shin Cho SW Development Section POSDATA FLYVO Research and Development Center Gyeonggi South Korea School of Electrical Engineering and Computer Science Kyungpook National University Daegu South Korea Department of Information and Communication Engineering Dongeui University busan South Korea

In this paper, a preemptive priority queueing model is developed to describe the traffic behavior of secondary users in cognitive radio systems. As the performance measures, the system dwelling time for non-real-time ... 详细信息

关键词： Servers Mathematical model Real time systems Cognitive radio Time frequency analysis Electronic mail Load modeling

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Model predictive control of a nonlinear fed-batch fermentation process

Model predictive control of a nonlinear fed-batch fermentati...

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International Conference on control, Automation, Robotics and Vision (ICARCV)

作者： Ahmad Ashoori Amir Hosein Ghods Ali Khaki-Sedigh Mohammad Reza Bakhtiari Control and Intelligence Processing Center of Excellence School of ECE University of Tehran Tehran Iran Department of Electrical Engineering K.N. Toosi University of Technology Tehran Iran Iranian Research Organization for Science and Technology Tehran Iran

Bioprocesses, which are involved in producing different antibiotics and other pharmaceutical products, may be conveniently classified according to the mode chosen for the process: either batch, fed-batch or continuous. From the control engineer's viewpoint it is the fed-batch processes, however, which present the greatest challenge to get a pure product with a high concentration. To achieve this goal, control of the following parameters has significant importance dealing with these processes: temperature, pH, dissolved oxygen (DO2). Bioprocesses have complicated dynamics. Hence, their control is a delicate task; Nonlinearity and non-stationarity, which make modeling and parameter estimation particularly difficult perturbs such processes. Moreover, the scarcity of on-line measurements of the component concentrations (essential substrates, biomass and products of interest) makes this task more sophisticated. In this paper, Model predictive control (MPC) based on a detailed unstructured model for penicillin production in a fed-batch fermentor has been developed. MPC is performed via determining the control signal by minimizing a cost function in each step. The results of this controller to maximize penicillin concentration have been displayed and also compared with the results of auto-tuned PID controller used in previous works.

关键词： Predictive models Predictive control Antibiotics Pharmaceuticals Temperature control Parameter estimation Biomass Production Cost function Three-term control

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