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IEEE International Symposium on Compound Semiconductors

作者： W.M. Jadwisienczak H.J. Lozykowski School of Electrical Engineering & Computer Science and Condensed Matter & SurfaceSciences ProgramStocker Center Ohio University Athens OH USA

Photoluminescence spectra, excitation spectra and decay kinetics of epitaxial GaN layers grown by MOCVD on sapphire substrates and implanted by isoelectronic impurities P and Bi were investigated. Post implant annealing up to 1150/spl deg/C, and different duration time was done in a tube furnace under flowing NH/sub 3/ or N/sub 2/ using proximity cap method to recover implantation damages. The PL of GaN:P shows strong emission peaked at 423 nm-428 nm with modulated structures that depend on annealing condition. The PL of GaN: Bi shows luminescence transitions, observable in a wide temperature range from 9 K to 300 K. Further, we develop the luminescence models that describe the recombination and quenching processes.

关键词： Photoluminescence Gallium nitride Bismuth Annealing Luminescence Kinetic theory MOCVD Substrates Impurities Implants

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1D representations and systems theory for a class of 2D linear systems 4

1D representations and systems theory for a class of 2D line...

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4th European Control Conference, ECC 1997

作者： Galkowski, K. Rogers, E. Owens, D.H. Department of Robotics and Software Engineering Technical University of Zielona Gora ul. Podgorna 50 Zielona Gora65-246 Poland ISIS Group Dept. Electronics and Computer Science University of Southampton SouthamptonSO17 1BJ United Kingdom School of Engineering University of Exeter North Park Road ExeterEX4 4QF United Kingdom

ISBN: (纸本)9783952426906

Repetitive, or multipass, processes are a class of systems characterised by a series of sweeps through a set of dynamics defined over a finite fixed duration. The class of so-called discrete linear repetitive processes have strong structural links with well studied classes of 2D linear systems and also with standard (1D) linear systems. One possible approach to the (control related) analysis of these processes is to embed their basic 2D structure in a 1D representation. This paper develops such a representation and uses it to characterise the key systems theoretic property of controllability for this class of linear repetitive processes.

关键词： Linear systems

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Tropism-based cognition for the interpretation of context-dependent gestures

Tropism-based cognition for the interpretation of context-de...

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IEEE International Conference on robotics and Automation (ICRA)

作者： R.M. Voyles A. Agah P.K. Khosla G.A. Bekey Robotics Ph.D. Program Carnegie Mellon University Pittsburgh PA USA Bio Robotics Division Mechanical Engineering Laboratory Tsukuba Japan Department of Elect. and Comp. Eng Carnegie Mellon University Pittsburgh PA USA Department of Computer Science University of Southern California Los Angeles CA USA

The tropism system cognitive architecture provides an intuitive formalism for colonies of agents, either hardware or software. We present a fine-grained implementation of the architecture on a colony of software agents for the interpretation of human tactile gestures for robotic trajectory specification and modification. The fine-grained nature of the architecture and the use of the port-based object framework for agent instantiation allows the manual construction of a capable agent set that is reconfigurable and reusable across different gesture-based interaction tasks.

关键词： Cognition Cognitive robotics Shape computer architecture Robot sensing systems Manipulators Humans Multiagent systems Robot programming Mice

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Design decision support system for the engineering/re-engineering of complex naval systems

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NAVAL ENGINEERS JOURNAL 1997年第4期109卷 23-33页

作者： Graham, JH Ragade, RK Shea, J James H. Graham:is the Henry Vogt Professor of computer science and engineering at the University of Louisville. Previous professional employment includes positions at Rensselaer Polytechnic Institute and General Motors Corporation. He received his master's and doctoral degrees at Purdue University and his bachelor's degree at Rose-Hulman Institute of Ethnology. His research interests include artificial intelligence robotics and paraliel computing. Rammohan K. Ragade:is professor of engineering mathematics and computer science at the University of Louisville. He received his Ph.D. from the Indian Institute of Technology at Kampur in 1968. He has been a faculty member at the University of Waterloo and held an engineering position with Bell Northern Research. His research interests include human-computer interaction decision support systems object-oriented simulation and modeling distributed database systems and fuzzy logic. John G. Shea Jr.:served until 1995 as a project manager in the Phalanx Engineering Section of Naval Surface Warfare Center Crane Division Louisville Station. He received his bachelor's and master's degrees from the Speed Scientific School at the University of Louisville. He was a member of the American Society of Naval Engineers.

Hybrid simulation includes both functional computer software models and actual hardware subsystems operating as an integrated whole. A ''hot test bed'' or a ''hybrid simulator-emulator'' enables design engineers to evaluate conceptual models in a more realistic real-lime context, but places increased cognitive demands on the designer. This paper describes an architecture, and results from a prototype implementation, for a design decision support system to allow a designer to make more productive and cost effective use of a test bed system.

关键词： Decision support systems

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Meeting the 21st century with SMART mission flexibility

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NAVAL ENGINEERS JOURNAL 1997年第3期109卷 341-346页

作者： Alexander, RK Olmstead, L Ronald K. Alexander P.E.:received his B.S. degree in mechnaical engineering from Purdue University and his M.S. degree in mechanical engineering from the Naval Postgraduate School. He is currently manager quality programs at RGE Engineering Service Company where he provides technical support to the ATC Program in the area of combat system modularity design. lhe is a member of ASNE and the Surface Navy Association. Larry Olmstead:received his B.L.S. degree in mathematics and computer scienc from Mary Washington College in 1982 and his M.S. degree in system management from the University of Southern California in 1986. He chaired the C'I Modular Implementation Wroking Group (MIWG) from its inception in September 1993 to December 1996 as a combat system engineer in the PEO CLA Engineering management Office (Code PMS307). He is currently employed at Science Application International Corporation.

A revolution is underway in the design, production and installation of the Navy/Marine Corps team's command, control, communications, computers and intelligence ((CI)-I-4) vision and strategies, which is significantly reducing costs, and dramatically improving the battle readiness of tomorrow's forward deployers. A strong emphasis on research and development has enabled the design, development and installation of the Shipboard Modular Arrangement Reconfiguration Technology (SMART) systems in ships. SMART is a methodology for installing equipment in shipboard spaces that will provide the fleet with enhanced mission flexibility. The heart of this technology is a track rail system, similar to that used by the aircraft industry, which enables equipment to be bolted to the deck, bulkheads or overhead, and meets all shipboard shock and vibration requirements. The fleet can reconfigure designated spaces to receive new systems, install equipment upgrades, position cross-decked systems, or rearrange work areas with minimal industrial work (welding, grinding, lagging, painting, etc.), and maximum cost savings. Key (CI)-I-4 spaces such as Tactical Flag Command Center (TFCC), Joint Operations Center (JOC), Communication Centers, etc., can be reconfigured as required. Thereby, new technology insertion can enable rapid deployment of state-of-the-art technologies much faster than the standard method of welding foundations in place to support various equipment installations. The SMART system includes a foundation track system, modular-connectorized power and lighting, and modular workstations.

关键词： Naval vessels

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Operational systems, logistics engineering and technology insertion

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NAVAL ENGINEERS JOURNAL 1997年第3期109卷 205-220页

作者： Grubb, MJ Skolnick, A Michael J. Grubb:has perfomzed naval engineering at the Crane Division Naval Surface Warfare Center (NSWC) for more than twenty-five years. He currently the program manager for the Sustainable Hardware and Affordable Readiness Practice Program (SHARP). is a Navy-wide logistics research and development prgram aimed at the successful transiton of proved technologies inot the fleet. SHARP focuses on reducing acquisition performance capability reliability maintainability and readiness of these systems. Mr. Grubb has served as a department director for the past eleven years. His most recent assignment was as director of the Tactical Computer Resources and Test Equipment Department. This organization provided acquisition and in-service engineering support of the Navy's tectical embedded computers priphirals displays and mass memory storage devices. The organization also provided a complete range of product engineering and metrology engineerig services for SSP NevSeaSysCom and the Trident Program. Prior to this appointment Mr. Grubb was deptuy director psysical security programs department and site responsible for program management and system integration of ashore integrated security systems. Mr. Grubb holds a B.S. degree in industrial engineering from Iowa State Universtiy an M.S. degree in industrial engineering from Purdue University and has copleted the course work (Dec.'96 for a master's degree in public and environment affairs at Indiana University-Purdue Univeristy Indianapolis. Dr. Alfred Skolnick operates System Science Consultants (SSC) specilizing in strategic planning technical program definiton technology assessment and engineering analyses on selected matters of national interest. He has taught physics mathematics and management sciences at University of Virginia and Marymount University and is currently adjunct professor of mathematics at Northern Virginia Community College. Form 1985 to 1989 he was president of the American Society of Noval Engineers. Dr. Skolnick served at Applied Physic

In an era of fiscal austerity, downsizing and unforgiving pressure upon human and economic capital, it is an Augean task to identify resources for fresh and creative work. The realities of the day and the practical demands of more immediate fleet needs can often dictate higher priorities. Yet, the Navy must avoid eating its seed corn. Exercising both technical insight and management foresight, the fleet, the R&D community, the Office of the Chief of Naval Operations (OpNav) and the product engineering expertise of the Naval Surface Warfare Center (NSWC) are joined and underway with integrated efforts to marry new, fully demonstrated technologies and operational urgencies. Defense funding today cannot sponsor all work that can be mission-justified over the long term because budgets are insufficient to support product maturation within the classical development cycle. However, by rigorous technical filtering and astute engineering of both marketplace capabilities and currently available components, it is possible in a few select cases to compress and, in effect, integrate advanced development (6.3), engineering development (6.4), weapon procurement (WPN), ship construction (SCN), operation and maintenance (O&M,N) budgetary categories when fleet criticalities and technology opportunities can happily meet. In short, 6.3 funds can be applied directly to ''ripe gateways'' so modern technology is inserted into existing troubled or aging systems, sidestepping the lengthy, traditional development cycle and accelerating practical payoffs to recurrent fleet problems. To produce such constructive results has required a remarkable convergence of sponsor prescience and engineering workforce excellence. The paper describes, extensively, the philosophy of approach, transition strategy, polling of fleet needs, technology assessment, and management team requirements. The process for culling and selecting specific candidate tasks for SHARP sponsorship (matching operational need with t

关键词： Naval vessels

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What programmable vector fields can (and cannot) do: force field algorithms for MEMS and vibratory plate parts feeders

What programmable vector fields can (and cannot) do: force f...

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IEEE International Conference on robotics and Automation (ICRA)

作者： K.-F. Bohringer B.R. Donald N.C. MacDonald Robotics & Vision Lab. Cornell Univ. Ithaca NY USA Robotics & Vision Laboratory Department of Computer Science Cornell University Ithaca NY USA School of Electrical Engineering and Cornell Nanofabrication Facility Cornell University Ithaca NY USA

programmable vector fields can be used to control a variety of flexible planar parts feeders. When a part is placed on our devices, the programmed vector field induces a force and moment upon it. Over time, the part may come to rest in a dynamic equilibrium state. We demonstrate lower bounds on what the devices cannot do, and results on a classification of control strategies. We suggest sufficient conditions for programmable fields to induce well-behaved equilibria on every part placed on our devices. We define composition operators to build complex strategies from simple ones, and show the resulting fields are also well-behaved. We discuss whether fields outside this class can be useful and free of pathology. Using these tools, we describe new manipulation algorithms, and improve existing planning algorithms by a quadratic factor, and the plan-length by a linear factor. We relax earlier dynamic and mechanical assumptions to obtain more robust and flexible strategies. Finally, we consider parts feeders that can only implement a very limited "vocabulary" of vector fields. We discuss the trade-off between mechanical complexity and planning complexity.

关键词： Micromechanical devices Automatic control Force control Feeds Assembly Robot vision systems Laboratories computer science Nanofabrication Uniform resource locators

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The Time Optimal Control Problem for a class of Nonholonomic Systems: A Case Study

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IFAC Proceedings Volumes 1996年第1期29卷 2325-2329页

作者： Z. Retchkiman F. Khorrami Centro de Investigación en Matemáticas Aplicadas Universidad Autónoma dc Coahuila Campo Redonda Edificio S Apdo. Postal 60-C Saltillo Coahuila México Control/Robotics Research Laboratory (CRRL) School of Electrical Engineering and Computer Science Polytechnic University Six Metrotech Center Brooklyn New York 11201 U.S.A.

The minimum time control problem for a class of non-holonomic controllable nonlinear systems is considered in this paper. These nonlinear systems have drift free dynamics with fewer controls than states. After some review and preliminar results, it is shown, that in general the problem is not solveable. Next, under some restrictions on the control inputs we are able to characterize the zero crossing set and to get solutlOns which result to be of the bang-bang form. Finally, a case study is presented where the proposed solution is compared with other methodologies which solve the point to point motion planning problem, showing that indeed is the best, one can obtain.

关键词： Time optimal control nonholonomic systems singular arc bang bang controls

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POSITIONING OF UNKNOWN FLEXIBLE PAYLOADS FOR ROBOTIC ARMS USING A WRIST-MOUNTED FORCE/TORQUE SENSOR

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IEEE TRANSACTIONS ON CONTROL SYSTEMS TECHNOLOGY 1995年第2期3卷 189-201页

作者： JAIN, S KHORRAMI, F Control /Robotics Research Laboratory School of Electrical Engineering and Computer Science Polytechnic University Brooklyn NY USA

The Problem of control design for robotic arms manipulating unknown flexible payloads is considered in this paper, A novel scheme utilizing a force/torque sensor at the wrist of the manipulator is utilized, This choice of sensor is adequate to glean information about payload vibrations without outfitting the payload with sensors and offers the additional advantage of furnishing a minimum phase system, thus simplifying the control design, A controller utilizing wrist torque feedback from the sensor is designed as a function of the system parameters, An adaptive scheme for on-line identification of these parameters and adaptation of controller parameters is discussed, The proposed scheme is generic in regard to the nature of the flexible payload, as is shown through simulation studies, The scheme is implemented on a single-link manipulator carrying an unknown flexible payload, Simulation and experimental results validate the fact that the adaptive control maintains a robust performance for high speed slewing and varying payloads.

关键词： Payloads Arm Sensor systems Robot sensing systems Control design Wrist Adaptive control Force sensors Torque Manipulators

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EXPERIMENTAL RESULTS ON ADAPTIVE NONLINEAR CONTROL AND INPUT PRESHAPING FOR MULTILINK FLEXIBLE MANIPULATORS

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AUTOMATICA 1995年第1期31卷 83-97页

作者： KHORRAMI, F JAIN, S TZES, A School of Electrical Engineering and Computer Science Control/Robotics Research Laboratory (CRRL) Polytechnic University Brooklyn NY 11201 United States Department of Mechanical Engineering Control/Robotics Research Laboratory (CRRL) Polytechnic University Brooklyn NY 11201 United States

Adaptive input precompensators in conjunction with nonlinear controllers for multi-link flexible manipulators are considered in this paper. In an earlier paper, we had shown that application of a nonlinear inner-loop control reduces the variations in frequencies due to the geometrical configuration for multi-link flexible manipulators. This results in a better performance when input preshaping or any other controller based on a linear model is designed. To improve the performance of the system to parameter variations (e.g. changes in payload), an adaptive version of the advocated controller is utilized. This is achieved by estimating the time of application of the impulses for on-line preshaping and in the case of payload uncertainty, estimation of the payload and real-time adjustment of the nonlinear inner-loop based controller. Frequency domain Time-Varying Transfer Function Estimate (TTFE) and Empirical Transfer Function Estimate (ETFE) system identification algorithms are proposed for estimation of vibrational modes and unknown payload. Experimental results on a two-link flexible manipulator with adaptive nonlinear control and preshaping are provided to show the effectiveness of the advocated controllers. Overall, the present paper completely generalizes the adaptive input preshaping technique for multi-link flexible manipulators.

关键词： FLEXIBLE MANIPULATORS VIBRATION DAMPING NONLINEAR CONTROL INPUT PRESHAPING IDENTIFICATION ADAPTIVE CONTROL

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