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IEEE Conference on Vehicular Technology (VTC)

作者： C.-L. Liu K. Feher Digital Communications Research Laboratory Department of Electrical Engineering and Computer Science University of California슠Davis Davis CA USA Department of Electrical Engineering and Computer Science University of California Davis Davis CA USA

A novel fade estimation and compensation method based on the pilot symbol insertion (PSI) concept is proposed and analyzed for coherent pi /4-QPSK (quadrature phase shift keying) modems. The estimated fade characteristics are used to compensate the random phase modulation caused by the Doppler spread in a fast Rayleigh fading channel so that the signals can be demodulated coherently. The theoretical performance of the fade compensated coherent modem in a frequency-selective fast Rayleigh fading channel corrupted by additive white Gaussian noise and cochannel interference is evaluated. The results show that the fade compensated coherent demodulation achieves the same performance as noncoherent demodulation in a slow fading channel. The main advantage of the proposed technique is that it removes the error floor caused by Doppler spread in a fast fading channel.< >

关键词： Modems Fading Demodulation Phase modulation Frequency digital communication Phase estimation AWGN Baseband Transmitters

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Miller coded pilot aided modulation schemes for digital mobile radio

Miller coded pilot aided modulation schemes for digital mobi...

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IEEE Conference on Vehicular Technology (VTC)

作者： D. Subasinghe-Dias K. Feher Digital Communications Research Laboratory Department of Electrical Engineering and Computer Science University of California슠Davis Davis CA USA Department of Electrical Engineering and Computer Science University of California Davis Davis CA USA

The performance of Miller coded pilot aided modulation systems is studied by computer-aided design techniques. It is shown that the use of this nonredundant code may improve the bit error rate (BER) performance of pilot aided modulation schemes over similar uncoded coherent and noncoherent systems. Miller coded random data have a spectral density about 12 dB lower than uncoded data at and around the unmodulated carrier frequency. The use of this code reduces the interference between the data spectrum and the pilot tone, and hence improves the BER performance. This improvement is significant, particularly in low bit-rate systems where a relatively wide bandpass filter is required for pilot extraction and successful compensation for fading and Doppler shift caused phase variations. This improved BER performance is obtained with no redundancy, but at the cost of some spectral efficiency.< >

关键词： digital modulation Modulation coding Bit error rate Design automation Frequency Interference Band pass filters Data mining Fading Doppler shift

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Development of micro actuator using shape memory alloy thin film

Development of micro actuator using shape memory alloy thin ...

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EEE International Workshop on Intelligent Robots and systems, Towards a New Frontier of Applications

作者： K. Ikuta H. Fujita S. Arimoto M. Ikeda S. Yamashita Department of Mechanical System Engineering Faculty of Computer Science and System Engineering Kyushu Institute of Technology Fukuoka Japan Institute of Industrial Science University of Tokyo Tokyo Japan Department of Mathematical Engineering and Information Physics Faculty of Engineering University of Tokyo Tokyo Japan Research Laboratory Yaskawa Electric Manufacturing Company Limited Japan

Basic research for the micro actuator using TiNi shape memory alloy (SMA) is conducted from the crystallographic point of view. SMA (TiNi) thin film is fabricated by sputter deposition. First, the influence of substrate temperature on crystal structure is verified by measuring resistivity-temperature curve and X-ray diffraction. Though high temperature substrate conditions make TiNi film in regular crystal, an amorphous structure appears at low substrate temperature. Next optimal composition of sputtered SMA thin film is found by SSQ. The negative slope of the resistivity curve due to phase transformation between R-phase and parent phase is observed. Finally, annealing methods are examined to crystallize amorphous TiNi.< >

关键词： Microactuators Shape memory alloys Transistors Sputtering Substrates Temperature Crystallization Amorphous materials Crystallography X-ray diffraction

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A finger shaped tactile sensor using an optical waveguide

A finger shaped tactile sensor using an optical waveguide

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Annual Conference of Industrial Electronics Society

作者： N. Nakao M. Kaneko N. Suzuki K. Tanie NTT Tsukuba Field Engineering Development Center Tsukuba Ibaraki Japan School of Computer Science and System Engineering Department Kyushu Institute of Technology Fukuoka Japan Cybernetics Division Robotics Department Mechanical Engineering Laboratory Tsukuba Ibaraki Japan

A finger-shaped tactile sensor consisting of a charge-coupled device (CCD) and a semispherical optical waveguide covered with an elastic sheet and connected to a light source is proposed. The principle of the sensor is based on producing the scattering light at the sensor-object contact. The contact location is recognized using a CCD to detect light. By a simple calculation of the equation derived from the sensor surface geometry, the sensor can also provide the surface normal of the touched object. Through experiments using a prototype sensor, the fundamental characteristics of the sensor are evaluated and the principle of the sensor is confirmed.< >

关键词： Optical waveguides Fingers Tactile sensors Optical sensors Sensor phenomena and characterization Optical scattering Charge coupled devices Optical surface waves Optical devices Light sources

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Rapid system prototyping in academic laboratories of the 1990s

Rapid system prototyping in academic laboratories of the 199...

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International Workshop on Rapid system Prototyping (RSP)

作者： A. Dollas V. Chi Digital Systems Laboratory Department of Electrical Engineering Duke University Durham NC USA Microelectronic Systems Laboratory Department of Computer Science University of North Carolina Chapel Hill Chapel Hill NC USA

The term "rapid system prototyping" is introduced in the context of academic research in digital systems. The technological issues as well as issues of policy which affect system prototyping in academia are presented, as well as opportunities stemming from a rapid system design cycle. The complementary role of academia and industry in the development of systems is outlined.< >

关键词： Prototypes Laboratories Hardware digital systems Standardization Software prototyping Silicon Buildings Area measurement Microelectronics

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A Methodology for Evaluating Decision Making Architectures for Automated Manufacturing systems

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IFAC Proceedings Volumes 1990年第8期23卷 321-326页

作者： R.Y. Al-Jaar A.A. Desrochers System Modeling Group Digital Equipment Corporation 4 Results Way MRO4-1/H17 Marlboro MA 01752-9122 USA Electrical Computer and Systems Engineering Department Rensselaer Polytechnic Institute Troy NY 12180-3590 USA

Controlling complex computer integrated manufacturing systems requires the design of an equally complex system of computers whose topology forms a real-time Decision Making Architecture (DMA) consisting of control, communication, and database functions, The purpose of the DMA is to ensure that production operations proceed on schedule, and to detect and correct any errors in real-time, The choice of a DMA greatly influences the performance of the overall manufacturing system. A generic methodology for evaluating DMAs is proposed. Each computer is modeled as a Decision Making Unit (DMU) using Generalized Stochastic Petri Nets (GSPNs). Each DMU represents the functions of a typical computer in a manufacturing environment. DMU modules serve as basic building blocks that can be easily interconnected to model any desired DMA. The measure of performance is the response time, and a procedure for computing it is described. Two- and three-level hierarchical DMAs are evaluated by automatically solving the equivalent Markov Chain of the GSPN model.

关键词： Performance evaluation Generalized Stochastic Petri Nets Markov models automated manufacturing systems decision making architectures hierarchical control architectures

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AEGIS AAW CORRELATOR TRACKER (AACT) EXPERIMENT

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NAVAL ENGINEERS JOURNAL 1990年第3期102卷 37-42页

作者： GRANT, CJ The Author:is an assistant group supervisor of the Anti-Air Warfare Systems Engineering Group in the Fleet Systems Department of The Johns Hopkins University Applied Physics Laboratory (JHU/APL). He received a B.S. in physics from the University of Maryland in 1978 an M.S. in applied physics and an M.S. in computer science from The Johns Hopkins University in 1982 and 1984 respectively. Since joining JHU/APL in 1978 Mr. Grant has been involved in the development and integration of advanced command support systems and communications in U.S. Navy shipboard combat systems with particular emphasis on the Aegis Combat System. He is currently the lead engineer of the Command Support At Sea Experiment in which an Aegis AAW Correlator/Tracker capability is being developed for shipboard evaluation.

The Johns Hopkins University Applied Physics laboratory, in continuing development of the Aegis Command and Control capabilities aboard USS Ticonderoga class cruisers and USS Arleigh Burke class destroyers, under the direction of the Aegis Shipbuilding Project (PMS-400), is in the process of developing the Aegis AAW Correlator/Tracker (AACT) to experiment with and evaluate the capability to correlate track and contact data from over-the-horizon (OTH) sources and sensors with the shipboard real-time tactical picture. AACT, which is based on multi-hypothesis correlation algorithms, is intended to be fully automated; requiring little or no operator interaction in spite of ambiguous or conflicting data. Unlike other OTH correlator/tracker designs, the experimental AACT capability is highly integrated with the combat system. It makes maximum use of the shipboard sensor data, such as that provided by the AN/SPY-1 radar, to provide the basis from which to correlate the OTH data in areas of mutual sensor coverage. This approach helps to resolve the traditional conflicts between the tactical picture derived from battle group sensors and that derived from OTH sensors, and provides command the track data in the formats, rates, and timeliness needed to fight the AAW battle. This paper describes the AACT concept, design, and implementation. It addresses the plans for installation of AACT aboard an Aegis cruiser for evaluation of this capability in an operational environment.

关键词： computer Graphics

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computer-system ARCHITECTURE CONCEPTS FOR FUTURE COMBAT systemS

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NAVAL ENGINEERS JOURNAL 1990年第3期102卷 43-62页

作者： ZITZMAN, LH FALATKO, SM PAPACH, JL Dr. Lewis H. Zitzman:is the group supervisor of the Advanced Systems Design Group Fleet Systems Department The Johns Hopkins University Applied Physics Laboratory (JHU/APL). He has been employed at JHU/APL since 1972 performing applied research in computer science and in investigating and applying advanced computer technologies to Navy shipboard systems. He is currently chairman of Aegis Computer Architecture Data Bus and Fiber Optics Working Group from which many concepts for this paper were generated. Dr. Zitzman received his B.S. degree in physics from Brigham Young University in 1963 and his M.S. and Ph.D. degrees in physics from the University of Illinois in 1967 and 1972 respectively. Stephen M. Falatko:was a senior engineering analyst in the Combat Systems Engineering Department Comptek Research Incorporated for the majority of this effort. He is currently employed at ManTech Services Corporation. During his eight-year career first at The Johns Hopkins University Applied Physics Laboratory and currently with ManTech Mr. Falatko's work has centered around the development of requirements and specifications for future Navy systems and the application of advanced technology to Navy command and control systems. He is a member of both the Computer Architecture Fiber Optics and Data Bus Working Group and the Aegis Fiber Optics Working Group. Mr. Falatko received his B.S. degree in aerospace engineering with high distinction from the University of Virginia in 1982 and his M.S. degree in applied physics from The Johns Hopkins University in 1985. Mr. Falatko is a member of Tau Beta Pi Sigma Gamma Tau the American Society of Naval Engineers and the U.S. Naval Institute. Janet L. Papach:is a section leader and senior engineering analyst in the Combat Systems Engineering Department Comptek Research Incorporated. She has ten years' experience as an analyst supporting NavSea Spa War and the U.S. Department of State. She currently participates in working group efforts under Aegis Combat System Doctrin

This paper sets forth computer systems architecture concepts for the combat system of the 2010–2030 timeframe that satisfy the needs of the next generation of surface combatants. It builds upon the current Aegis computer systems architecture, expanding that architecture while preserving, and adhering to, the Aegis fundamental principle of thorough systems engineering, dedicated to maintaining a well integrated, highly reliable, and easily operable combat system. The implementation of these proposed computer systems concepts in a coherent architecture would support the future battle force capable combat system and allow the expansion necessary to accommodate evolutionary changes in both the threat environment and the technology then available to effectively counter that threat. Changes to the current Aegis computer architecture must be carefully and effectively managed such that the fleet will retain its combat readiness capability at all times. This paper describes a possible transition approach for evolving the current Aegis computer architecture to a general architecture for the future. The proposed computer systems architecture concepts encompass the use of combinations of physically distributed, microprocessor-based computers, collocated with the equipment they support or embedded within the equipment itself. They draw heavily on widely used and available industry standards, including instruction set architectures (ISAs), backplane busses, microprocessors, computer programming languages and development environments, and local area networks (LANs). In this proposal, LANs, based on fiber optics, will provide the interconnection to support system expandability, redundancy, and higher data throughput rates. A system of cross connected LANs will support a high level of combat system integration, spanning the major warfare areas, and will facilitate the coordination and development of a coherent multi-warfare tactical picture supporting the future combatant command st

关键词： computer Architecture

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THE COMMAND SUPPORT AT-SEA EXPERIMENT

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NAVAL ENGINEERS JOURNAL 1990年第3期102卷 25-36页

作者： BUSCHER, DJ SUNDAY, DM David J. Buscher:is an electrical engineer on the Principal Professional Staff of the Fleet Systems Department of The Johns Hopkins University Applied Physics Laboratory. He earned his BS degree in electrical engineering from Villanova University in 1967 an MSEE degree from the University of Maryland in 1972 and an MS degree in technical management from The Johns Hopkins University in 1985. He was the lead engineer on the Command Support At-Sea Experiment Project. He started his career in 1967 with the U.S. Army Harry Diamond Laboratory working on computer and communications projects. During this time he worked in Vietnam with the United States Army Vietnam Science Advisor Office. Since joining JHU/APL in 1978 he has worked on a variety of projects associated with computer graphics hospital patient information systems computer networks autonomous underwater vehicles and satellite communications. He is currently assistant group supervisor of the Computer Systems Group. Daniel M. Sunday:is a mathematician on the Principal Professional Staff of the Fleet Systems Department of The Johns Hopkins University Applied Physics Laboratory. He earned his Ph.D. in mathematics from the University of Minnesota in 1971 and did postdoctoral research on neural networks at the University of California at Berkeley. Since joining JHU/APL in 1980 Dr. Sunday has worked as a designer and developer of software systems with emphasis on medical imaging interactive graphics natural language interfaces and software standards. He was the network designer for the Headquarters Integrated Office System (HIOS) Network for the Army at the Pentagon. He is currently the lead software engineer on the Command Support At-Sea Experiment Project.

The Command Support At-Sea Experiment (CS@SE) provides experimental advanced graphics display systems consisting of large screen color displays and operator console color displays in the combat information center (CIC) of an Aegis cruiser and in the tactical flag command center (TFCC) of an aircraft carrier. CS@SE systems are designed to prototype potential command support capabilities in an at-sea environment to validate and refine requirements for planned production system upgrades. These systems use sophisticated color graphics techniques to provide real-time tactical displays that improve the availability of information to an operator by reducing clutter through the use of color, area fill, transparen overlays and intensity coding of track symbols. Interfaces wen developed with the Aegis Display system (ADS), Shipboarc Gridlock system with Auto-correlation (SGS/AC), Flag Dats Display system (FDDS) and Tomahawk Engagement Planning and Exercise Evaluation system (TEPEE) that provided the data for the presentation of a tactical display. Display elements included both real-time and over-the-horizon (OTH) surface track data, velocity leaders, tags, uncertainty ellipses, and history trails. The display also included filled land masses, country boundaries, commercial airways, cities, graphics overlays (i.e., operational areas), weapon system missile performance contours, and engagement plans. This paper describes the experiment, its installation and integration into the shipboard environments of an Aegis cruiser (USS Leyte Gulf ) and an aircraft carrier (USS America , its usage by the ships companies and embarked staffs, and the experiment result! and findings. Key conclusions of the experiment are: 1 Advanced graphics color displays can significantly enhance the ability of the warfighter to assimilate a complex tactical display. 2 Both ships reported a requirement for a correlated OTH and real-time track display with the ability to clearly differentiate the two types

关键词： computer Graphics

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Intermodulation product statistics in multi-carrier radio systems

Intermodulation product statistics in multi-carrier radio sy...

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IEEE Conference on Vehicular Technology (VTC)

作者： T. Yang K. Feher Digital Communications Laboratory Department of Electrical Engineering and Coumputer Science University of California Davis CA USA Digital Communications Laboratory Department of Electrical Engineering and Computer Science University of California Davis CA USA

The authors study the probability distribution function (PDF) and cumulative probability distribution function (CPDF) of the IM (intermodulation) products in several nonlinearly amplified systems by computer simulations and hardware measurements. The statistics of the in-band and out-of-band IM products are found. Particular emphasis is given to the study of the CPDF of out-of-band IM products since it is shown that these can be the major cause of adjacent-channel-interference (ACI). It is demonstrated that the PDF of the out-of-band IM interference is not necessarily Gaussian and that this out-of-band IM noise may lead to more frequent peaks and to higher peaks or crest factors than practical Gaussian noise sources. Thus the BER (bit error rate) will be worse than that in the WGN (white Gaussian noise) case. On the contrary, in the case of in-band IM noise, the BER performance is better than that of the WGN case when C/N (carrier/noise ratio) is high enough.< >

关键词： Statistics Gaussian noise computer simulation Bit error rate digital communication Interference Statistical distributions Hardware Noise measurement Laboratories

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