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IEEE International Conference on Robotics and Automation (ICRA)

作者： Honglak Lee Yirong Shen Chih-Han Yu G. Singh A.Y. Ng Stanford University Stanford CA US Department of Electrical Engineering University of Stanford Stanford CA USA Scientific Computing and Computational Mathematics Program University of Stanford Stanford CA USA Computer Science Department University of Stanford Stanford CA USA

Legged robots can, in principle, traverse a large variety of obstacles and terrains. In this paper, we describe a successful application of reinforcement learning to the problem of negotiating obstacles with a quadruped robot. Our algorithm is based on a two-level hierarchical decomposition of the task, in which the high-level controller selects the sequence of foot-placement positions, and the low-level controller generates the continuous motions to move each foot to the specified positions. The high-level controller uses an estimate of the value function to guide its search; this estimate is learned partially from supervised data. The low-level controller is obtained via policy search. We demonstrate that our robot can successfully climb over a variety of obstacles which were not seen at training time

关键词： Learning Robot kinematics Legged locomotion Foot Mobile robots Leg Motion control Robotics and automation Path planning computer science

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A high - Speed reclosing operation with fault current limiter

A high - Speed reclosing operation with fault current limite...

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IASTED International Conference on Energy and Power Systems

作者： Fujita, Junya Iwatsuki, Toshiharu Yukita, Kazuto Hosoe, Tadashi Goto, Yasuyuki Ichiyanagi, Katsuhiro Hoshino, Yukio Yamamoto, Nobuyuki Sugimoto, Shigeyuki Avatchanakorn, Vichit Department of Electrical and Electronics Engineering Aichi Institute of Technology 1247 Yagusa Yachigusa Toyota Aichi 470-0392 Japan Research and Development Division Chubu Electric Power Co. Inc. 20-1 Kitasekiyama Ohdaka-cho Midori-ku Nagoya 459-8522 Aichi Japan Program in Computer Information Systems Assumption University ABAC Ramkhamhaeng Soi 24 Hua Mark Bangkok 10240 Thailand

ISBN: (纸本)0889865868

This paper proposes a new high-speed reclosing operation method to improve the stability in power system with the fault current limiter. From an angular velocity, a field system voltage and a phase of the generator, the proposed operation method calculates the optimum reclosing time domain. The fault current limiter is used the reactance type or the resistive type. The examination was carried out using the Inst. of electrical Engineers of Japan one-machine infinite bus system model in order to demonstrate the effectiveness of the proposed method. The Impact Ver2.3 was used in the computer simulation.

关键词： Limiters

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Work Function of Cathode Emitter Materials Obtained by Ab-initio Quantum Mechanical Modeling

Work Function of Cathode Emitter Materials Obtained by Ab-in...

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International Conference on Vacuum Electronics

作者： V. Vlahos E.F. Holby A.K. Berta D.D. Morgan J.H. Booske University of Wisconsin Madison Madison WI USA 1415 Engineering Dr. Madison WI University of Wisconsin Madison USA Interdisciplinary Materials Science Program Madison WI Department of Materials Science and Engineering University of Wisconsin Madison USA Department of Materials Science and Engineering Madison WI Department of Electrical and Computer Engineering University of Wisconsin-Madison Madison WI USA

The work function of a material is a very important figure of merit in determining the material's applicability as an efficient electron emitter. Consequently, the work function of a variety of materials utilized in both thermionic and field-assisted cathodes for electron emission was investigated computationally using ab-initio quantum mechanical modeling methods based on the density functional theory (DFT) approach (Hohenberg and Kohm, 1964). This approach enables the detailed and self-consistent treatment of a system utilizing quantum mechanical principles and yields accurate information pertaining to its electronic properties. Of particular interest are cesium-iodide (CsI) coated carbon-based cathodes (Shiffler et al., 2004), which comprise a very promising class of cold field emitters capable of operating at low global electric fields. However, the exact origin of their enhanced emission properties is not clear, and a better understanding is necessary for further improvement and optimization of this technology. We apply ab-initio quantum mechanical modeling for understanding the origin of the fundamental emission mechanisms of this material system

关键词： Cathodes Quantum mechanics Quantum computing Atomic layer deposition Materials science and technology Thermionic emission Electron emission Density functional theory Convergence of numerical methods Slabs

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Enhancement of light extraction in GaInN light-emitting diodes by conductive omni-directional reflectors

Enhancement of light extraction in GaInN light-emitting diod...

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Conference on Lasers and Electro-Optics (CLEO)

作者： Jong Kyu Kim J.-Q. Xi Hong Luo E. Fred Schubert Jaehee Cho Cheolsoo Sone Yongjo Park Electrical Computer and Systems Engineering Department Rensselaer Polytechnic Institute Troy NY USA Department of Physics Applied Physics and Astronomy Rensselaer Polytechnic Institute Troy NY USA Photonics Program Team Samsung Advanced Institute of Technology Suwon South Korea

Enhancement of light extraction in a GaInN light-emitting diode employing a conductive omnidirectional reflector consisting of GaN, an indium-tin oxide nanorod low-refractive-index layer, and an Ag layer is presented.

ISBN: (纸本)1557528136

关键词： Indium tin oxide Light emitting diodes Refractive index Gallium nitride Films Reflectivity Optical reflection

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Field-Measured Natural Frequencies of Delaware Memorial Bridge

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Transportation Research Record 2006年第1期1976卷 114 - 123页

作者： Ralph Alan Dusseau John R. Jones Ravi P. Ramachandran Carlos C. Sun Glenn Arr Civil and Environmental Engineering Program College of Engineering Rowan University 201 Mullica Hill Road Glassboro New Jersey 08028-1701. Delaware River and Bay Authority P.O. Box 71 New Castle DE 19720. Electrical and Computer Engineering Program College of Engineering Rowan University 201 Mullica Hill Road Glassboro New Jersey 08028-1701. Department of Civil and Environmental Engineering University of Missouri–Columbia E2509 Lafferre Hall Columbia MO 65211-2200.

The Delaware Memorial Bridge is a major suspension bridge that is critical to the tristate region of northern Delaware, southern New Jersey, and southeastern Pennsylvania. The Delaware Memorial Bridge consists of two nearly identical suspension bridges (hence, the nickname Twin Spans) that cross the Delaware River from southern New Jersey to northern Delaware. Field ambient vibration measurements of Structures 1 and 2 of the Delaware Memorial Bridge were conducted in June 2001 and September 2003. These measurements were used to derive the natural frequencies and modes of vibration for these structures. These field-measured frequencies and modes were then compared with each other and with computer-generated natural frequencies and modes of vibration derived for Structure 2 of the Delaware Memorial Bridge in 1997. Specifically, the 2001 seismometer-generated results for Structure 1 were compared with the 2003 accelerometer-generated results for Structure 1; the 2003 field-measured results for Structure 2 were compared with the 2003 field-measured results for Structure 1; and the 2003 field-measured results for Structure 2 were compared with the 1997 computer-generated results for Structure 2. Overall, these three types of comparisons indicated relatively good correlation for transverse motion but only fair correlation for longitudinal and vertical motion.

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ISHM implementation for Constellation Systems

ISHM implementation for Constellation Systems

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AIAA/ASME/SAE/ASEE 42nd Joint Propulsion Conference

作者： Figueroa, Fernando Holland, Randy Schmalzel, John Duncavage, Dan Crocker, Alan Alena, Rick NASA Stennis Space Center Stennis Space Center MS 39529 Rowan University Dept. of Electrical and Computer Engineering Glassboro NJ 08028 NASA Johnson Space Center Houston TX 77058 NASA Ames Research Center Moffett Field CA 94035 Science and Technology Division EA41 Stennis Space Center MS 39529 AIAA Department of Electrical and Computer Engineering Rowan University Glassboro NJ 08028 International Space Station Program OD NASA Johnson Space Center Houston TX 77058 Systems Division Mission Operations Directorate DF NASA Johnson Space Center Houston TX 77058 Intelligent Systems Division MS 269-4 Moffett Field CA 94035

ISBN: (纸本)1563478188

This paper addresses methodic implementation of a credible ISHM capability for elements of Constellation Systems. ISHM capability must be implemented by a combination of on-board and ground elements, each contributing to determining the health of systems in the most effective manner. Implementation of ISHM capability must evolve continuously to reach higher and higher levels of functional capability. The implication is that a sustainable approach must be defined in order to accomplish a believable capability. This paper describes the methodology, the elements, and the technology to implement ISHM capability throughout the life cycle of elements of Constellation Systems, reaching beyond individual elements that might have a limited life while the constellation moves on.

关键词： Spacecraft propulsion

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A Non-Rigid Image Registration Technique for 3D Ultrasound Carotid Images using a "Twisting and Bending" Model

A Non-Rigid Image Registration Technique for 3D Ultrasound C...

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Annual International Conference of the IEEE engineering in Medicine and Biology Society (EMBC)

作者： N.D. Nanayakkara B. Chiu A. Samani J.D. Spence J. Samarabandu A. Fenster Imaging Research Laboratories Robarts Research Institute and Graduate Program in Biomedical Engineering University of Western Ontario London ONT Canada Department of Medical Biophysics and Graduate Program in Biomedical Engineering University of Western Ontario London ONT Canada Departments of Neurology and Clinical Pharmacology Robarts Research Institute University of Western Ontario and Stroke Prevention and Atherosclerosis Research Centre London ONT Canada Department of Electrical & Computer Engineering University of Western Ontario London ONT Canada

Atherosclerosis at the carotid bifurcation resulting in cerebral emboli is a major cause of ischemic stroke. Most strokes associated with carotid atherosclerosis can be prevented by lifestyle/dietary changes and pharmacological treatments if identified early by monitoring carotid plaque changes. Sensitive monitoring of plaque changes in volume and morphology requires that 3D ultrasound (US) images of carotid plaque obtained at different time points be registered and evaluated for change. This registration technique should be non-rigid, since different head positions in image acquisitions cause relative bending and torsion in the neck, producing non-linear deformations between the images. We modeled the movement of the neck using a "twisting and bending model" with only six parameters for non-rigid registration. We used a Mutual Information (MI) based image similarity measure with the Powell optimization method as they have been used effectively in US image registration applications. For evaluation of our algorithm, we acquired 3D US carotid images from three subjects at two different head positions to simulate images acquired at different times. Then, we registered each image set using our "twisting bending model" based non-rigid registration algorithm. We calculated the Mean Registration Error (MRE) between the segmented vessel surfaces in the target image and the registered image using a distance-based error metric. We repeated the experiment with only rigid registration to compare the capabilities of the proposed algorithm in improving registration of 3D carotid US images. The average registration error was 1.03plusmn0.23 mm using our non-rigid registration technique, while it was 1.50plusmn0.50 mm when we applied the rigid registration alone

关键词： Image registration Ultrasonic imaging Atherosclerosis Monitoring Head Neck Bifurcation Morphology Mutual information Optimization methods

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Neural Recording Stability of Chronic Electrode Arrays in Freely Behaving Primates

Neural Recording Stability of Chronic Electrode Arrays in Fr...

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Annual International Conference of the IEEE engineering in Medicine and Biology Society (EMBC)

作者： Michael D. Linderman Vikash Gilja Gopal Santhanam Afsheen Afshar Stephen Ryu Teresa H. Meng Krishna V. Shenoy Stanford University Stanford CA US Department of Computer Science Stanford University Stanford California USA Department of Electrical Engineering Stanford University Stanford California USA School of Medicine Stanford University Stanford California USA Department of Neurosurgery Stanford University Stanford California USA Neurosciences Program Stanford University Stanford California USA

Chronically implanted electrode arrays have enabled a broad range of advances, particularly in the field of neural prosthetics. Those successes motivate development of prototype implantable prosthetic processors for long duration, continuous use in freely behaving subjects. However, traditional experimental protocols have provided limited information regarding the stability of the electrode arrays and their neural recordings. In this paper we present preliminary results derived from long duration neural recordings in a freely behaving primate which show variations in action potential shape and RMS noise across a range of time scales. These preliminary results suggest that spike sorting algorithms can no longer assume stable neural signals and will need to transition to adaptive signal processing methodologies to maximize performance

关键词： Stability Electrodes Prosthetics Prototypes Neural prosthesis Protocols Shape Noise shaping Sorting Signal processing algorithms

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A genetic algorithm for the optimization of cable routing

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Systems and computers in Japan 2006年第7期37卷 61-71页

作者： Ma, Xuan Iida, Kazuhiro Xie, Mengchun Nishino, Junji Odaka, Tomohiro Ogura, Hisakazu Graduate School of Engineering University of Fukui Fukui City 910-8507 Japan Wakayama National College of Technology Gobo City 644-0023 Japan Faculty of Automation and Information Engineering Xi an University of Technology B Techno College Department of Electrical and Computer Engineering Wakayama National College of Technology Information Processing Society of Japan China Mechanical Design Society Department of Systems Engineering University of Electro-Communications Japan Society for Fuzzy Theory and Intelligent Informatics Japanese Academy of Facial Studies Japan Society of Kansei Engineering Graduate Program of Nuclear Power and Energy Safety Engineering Graduate School of Engineering Fukui University IEEE CS ACM IPSJ IEICE JSMBET Department of Human and Artificial Intelligent Systems JSAI Japan SOFT IEEE

In this paper the authors propose a structural method for a genetic algorithm (GA) for the optimization problem of cable routing in which cables have to be laid optimally. When there are no limits on the layout routes, the optimal routes for the individual cables can be found using the Dijkstra method in a finite discrete graph. However, when there are limits on the capacity in the layout routes, optimization cannot be performed using the Dijkstra method. The proposed GA is a two-level hierarchical GA that uses chromosome coding involving two levels. The routes for each cable and the combinations of cable routes are defined respectively, and layout route selection is optimized overall through genetic operations involving these levels. Block crossover and block mutation are used as genetic operations in the first level. In addition, a method to take advantage of lethal genes, which do not satisfy the constraints and are generated in the second level is used. computer simulations confirm that the two-level hierarchical GA with these genetic operations functions effectively for the optimization problem of cable routing. © 2006 Wiley Periodicals, Inc.

关键词： Electric cable laying

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Assembling genomes on large-scale parallel computers 06

Assembling genomes on large-scale parallel computers

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International Symposium on Parallel and Distributed Processing (IPDPS)

作者： A. Kalyanaraman S.J. Emrich P.S. Schnable S. Aluru Department of Electrical and Computer Engineering Iowa State University Ames IA USA Bioinformatics and Computational Biology Program Iowa State University Ames IA USA Iowa State University Ames IA US Dept. of Electr. & Comput. Eng. Iowa State Univ. Ames IA USA

ISBN: (纸本)9781424400546

Assembly of large genomes from tens of millions of short genomic fragments is computationally demanding requiring hundreds of gigabytes of memory and tens of thousands of CPU hours. New gene-enrichment sequencing strategies are expected to further exacerbate this situation. In this paper, we present a massively parallel genome assembly framework. The unique features of our approach include space-efficient and on-demand algorithms that consume only linear space, and heuristic strategies that reduce the number of expensive pairwise sequence alignments while maintaining assembly quality. As part of the ongoing efforts in maize genome sequencing, we applied our assembly framework to the largest available collection of maize genomic data. We report the partitioning of more than 1.6 million fragments of over 1.25 billion nucleotides total size into genomic islands in 2 hours on 1,024 processors of an IBM BlueGene/L supercomputer.

关键词： Assembly Genomics Bioinformatics Large-scale systems Concurrent computing Sequences DNA Organisms Biology computing Biological cells

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