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IEEE Conference on Vehicular Technology (VTC)

作者： S. Saroor R. Kubichek J. Schroeder J. Lansford Electrical Engineering Department University of Wurzburg USA Electrical Engineering Department University of Wurzburg Laramie WY USA Department of Engineering University of Denver Denver CO USA Mobile Data System Colorado Springs CO USA

This paper describes the modeling and simulation of candidate AM subcarrier systems designed to transmit digital information for display on the dial of next generation radios. AM subcarrier technology still remains under-developed and its possible applications untapped. One such application of AM subcarriers is the Advanced Traffic/Traveler Information system. In the proposed system, the digital signal is inserted between the AM carrier and the audio sidebands. This paper investigates the effect of mutual interference between the audio and digital programs for a variety of digital modulation schemes, bit rates, and channel conditions. The GMSK subcarrier model exhibited the best overall performance in terms of spectrum efficiency and output signal-to-noise ratio.

关键词： Bit error rate Digital modulation Bit rate Analytical models data systems Auditory displays Information systems Interference Signal to noise ratio Radio broadcasting

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Disassemblability analysis for generating robotic assembly sequences

Disassemblability analysis for generating robotic assembly s...

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IEEE International Conference on Robotics and Automation (ICRA)

作者： C.K. Shin D.S. Hong H.S. Cho Samsung Data System Company Limited Seoul South Korea Department of Precision Engineering and Mechatronics Korea Advanced Institute of Science and Technology Daejeon South Korea

This paper proposes a mathematical approach to the analysis of disassemblability of a product for generating stable robotic assembly sequences. The disassemblability of a part, which represents a cost for disassembling the part from a base assembly, is derived in terms of both separability of a part from a base assembly and motion instability of the base assembly. Then, stable robotic assembly sequences are found in the list of parts, each of which is sequentially chosen to have a locally maximum disassemblability. To show the effectiveness of the proposed method, case studies are presented for industrial products. The results are compared with those of previous researches. The comparison shows that the proposed method can effectively generate stable robotic assembly sequences and provide essential informations on fixture design.

关键词： Robotic assembly Costs Assembly systems Gravity Fixtures data systems Precision engineering Mechatronics Computer errors Design automation

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Variable rate techniques for CELP speech coding

Variable rate techniques for CELP speech coding

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Asilomar Conference on Signals, systems & Computers

作者： J.D. Gibson M.L. Moodie S.A. McClellan Department of Electrical Engineering Texas A and M University College Station TX USA Automation & Data System Division Southwest Research Institute San Antonio TX USA Department of Electronics and Communication Engineering University of Alabama Birmingham AL USA

The development of variable-rate speech coding techniques has recently become an area of significant research interest, and several variable-rate schemes have been discussed in the literature. Here, we discuss general techniques for efficient variable-rate coding and the analysis cues from which these coding modes are derived. These techniques include fixed-update, variable-allocation and variable-update, fixed-allocation approaches to formant and pitch filter encoding. Since code-excited linear prediction (CELP) is popular for communications quality speech coding below 8 kbps, we provide simulation results for the several techniques in the context of variable-rate CELP coders with average encoded rate below 2 kbps.

关键词： Speech coding Distortion measurement Entropy Speech analysis Frequency measurement Degradation Encoding Automation Filters Context modeling

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DOMAIN-WALL MOBILITY MEASUREMENTS IN MAGNETOOPTIC MEDIA

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IEEE TRANSACTIONS ON MAGNETICS 1994年第6期30卷 4401-4403页

作者： DU, M KRYDER, MH Data Storage System Center Department of Electrical and Computer Engineering Carnegie Mellon University Pittsburgh PA USA

Domain wall motion Involved in both writing and erasing processes In Magneto-Optic(MO) recording Is strongly governed by domain wall mobility. This report extends our previous measurements by a highly Sensitive Kerr microscope system of domain wall mobility in MO media to temperature ranges near the Curie temperature (T-c). The velocity of wall motion is measured as a function of the applied field in samples of GdTbFe and GdTbFeCo, with different compositions and compensation temperatures. The experimental temperature ranges from 60 degrees C to 10 degrees C below T-c. The collected data show that for samples of different composition the domain wall mobilities increase approximately exponentially as the temperature approaches T-c from about 0.02 cm/sec-Oe to 5 cm/sec-Oe.

关键词： Magnetic field measurement Magnetic domain walls Temperature distribution Temperature sensors Velocity measurement Pulse measurements Microscopy Dielectric substrates Laser mode locking Magnetooptic recording

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Parallel relational database algorithms revisited for range declustered data sets

Parallel relational database algorithms revisited for range ...

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International Symposium on Parallel Architectures, Algorithms and Networks (ISPAN)

作者： E. Schikuta Institute of Applied Computer Science and Information System Department of Data Engineering University of Technology Vienna Austria

Today available parallel database systems use conventional parallel hardware architectures employing a highly parallel software architecture. It is an emerging technique to speed up the execution by declustering the stored data sets among a number of parallel and independent disk drives. In this paper we revisit parallel relational database algorithms for range declustering. We adapt the conventional known and well studied parallel algorithms for declustered data, exploit the inherent order property of the partitioned data sets and compare analytically the performance of the algorithms. It is shown that the parallel range declustered variants generally outperform their conventional parallel counterparts.< >

关键词： Relational databases Partitioning algorithms database systems Hardware Computer architecture Software architecture Disk drives Parallel algorithms Performance analysis Algorithm design and analysis

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Explicit fuzzy force control of industrial manipulators with position servo drives

Explicit fuzzy force control of industrial manipulators with...

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IEEE International Workshop on Intelligent Robots and systems (IROS)

作者： I.H. Suh K.S. Eom H.J. Yeo B.H. Kang S.-R. Oh B.H. Lee Intelligent Control and Robotics Laboratory Department of Electrvnics Engineering Hanyang University South Korea Samsung Data System Company Limited South Korea Division of Electronics and Infonmation technology KIST Seoul South Korea Robotics and Intelligent Systems Laboratory Department of Control and Instrumentation Engineering Seoul National University South Korea

In this paper, a fuzzy force control algorithm is suggested for commercialized industrial robots equipped with the position servo drives, where control rules of the proposed fuzzy controller are changed according to the magnitude of environmental stiffness in such a way that good force response is maintained regardless of changes of environmental stiffness. Specifically, some fuzzy control rules are designed for several representative environmental stiffness values, and then a control action for a given arbitrary environmental stiffness value is decided by a fuzzy interpolation method. To show the validity of the proposed fuzzy controller, several experimental results are illustrated, where a 5-axis articulated robot manipulator equipped with the wrist force/torque sensor system and our prototype dual robot controller are employed.< >

关键词： Fuzzy control Force control Industrial control Manipulators Torque control Control systems Robot sensing systems Commercialization Service robots Servomechanisms

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EFFECTS OF SAMPLE ISOLATION AND HANDLING ON THE RECOVERY OF PURGEABLE ORGANIC-COMPOUNDS

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GROUND WATER MONITORING AND REMEDIATION 1994年第2期14卷 142-152页

作者： GIBS, J IMBRIGIOTTA, TE FICKEN, JH PANKOW, JF ROSEN, ME Jacob Gibs is a water quality specialist with the USGS Water Resources Division (810 Bear Tavern Rd. Ste. 206 West Trenton NJ 08628). He received his B.S. in mechanical engineering in 1968 his M.S. in environmental engineering in 1975 and his Ph.D. in environmental engineering in 1983 all from Drexel University in Philadelphia. His research interests include evaluating representative ground water and surface water sampling techniques for trace levels of organic and inorganic compounds and designing new sampling devices. Thomas E. Imbrigiotta received a B.S. in chemistry with a concentration in environmental studies from Oakland University Rochester Michigan in 1975. He then attended the University of Wisconsin Madison and received an M.S. in water chemistry in 1982. He has been a hydrologist with the USGS Water Resources Division (810 Bear Tavern Rd. Ste. 206 West Trenton NJ 08628) since 1977. He worked in the Indiana District from 1977 to 1984 prior to coming to the New Jersey District. Currently he is project coordinator for the Picatinny Research project a study of the fate and transport of chlorinated solvents in ground water at Picatinny Arsenal New Jersey. Previously he was chief of a project evaluating sampling techniques for organics in ground water. James H. Ficken worked for the USGS Water Resources Division as a chemical engineer from 1964 to 1992. He received his B.S. in chemical engineering in 1962 from Washington University in St. Louis Missouri. His research interests were water quality instrumentation and sensors that measure real-time environmental data. He contributed as a team member to the design and development of the USGS water quality flow-through and mini-monitor system. Ficken passed away in 1992. James F. Pankow is a professor in the Department of Environmental Science and Engineering at the Oregon Graduate Institute (Oregon Graduate Institute of Science and Technology Department of Environmental Science and Engineering P.O. Box 1900 Portland OR 97291–1000). He

This report compares the recovery of purgeable organic compounds (POCs) obtained by using a downhole isobaric sampler developed by the U.S. Geological Survey, a helical-rotor submersible pump, and a point source bailer to collect and isolate samples of ground water from three wells in New York and New Jersey, the samples contained a total of 13 POCs detectable at concentrations ranging from 0.5 mug/L to about 400 mug/L. This report also compares the effects of sample handling, specifically the differences in POC concentration recovery when an isobaric sample container is filled at land surface vs. when it is filled downhole, and when samples are taken using a bailer with and without a bottom-emptying device. These case studies are used to quantify the possible effects of different sample-isolation and sample-handling techniques on POC recovery. The relative effectiveness of the three devices varied by site and by compound. Overall, the POC recoveries achieved by using the helical-rotor submersible pump and the downhole isobaric sampler were not significantly different at the 95 percent confidence level. POC recovery obtained by using the point source bailer was 11 percent lower overall. The downhole isobaric sampler results exhibited smaller coefficients of variation than did the helical-rotor submersible pump or the point-source bailer results. However, the differences between the coefficients of variation of the downhole isobaric sampler and those of the helical-rotor submersible pump were not significant the 95 percent confidence level. The nonsignificant smaller coefficient of variation of the downhole isobaric sampler apparently resulted from two fewer sample handling steps that exposed the sample water to ambient air. An independent experiment performed with a different downhole sampler at one of the wells used in this investigation produced a similar statistical result. Also, the POC recovery obtained by pouring sample water out the top Of a point source bail

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ASYNCHRONOUS TRANSFER MODE (ATM) OPERATION VIA SATELLITE - ISSUES, CHALLENGES AND RESOLUTIONS

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INTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS 1994年第3期12卷 211-222页

作者： CHITRE, DM GOKHALE, DS HENDERSON, T LUNSFORD, JL MATHEWS, N COMSAT Laboratories 22300 Comsat Drive Clarksburg MD 20871 USA. Received his B.Sc. from the University of Bombay India an M.A. in mathematics from the University of Cambridge U.K. and a Ph.D. in physics from the University of Maryland. He is currently an Associate Executive Director of the Network Technology Division at COMSAT Laboratories. He has been involved in research and development activities in ISDN VSAT networks data communications and network systems and architectures. Prior to his current positions Dr. Chitre was a Principal Scientist in the Network Technology Division at COMSAT Laboratories. Dr. Chitre joined COMSAT Laboratories in 1980. He has made major contributions to the analysis and architecture of data communication ISDN and BISDN via satellite. Dr. Chitre directs and participates in the international and national standards activities in ISDN BISDN and data communication as they apply to satellite communication. He was Chairman of the Working Group on Protocols and Network Timing Function of the CCIR/CCITT Joint Ad Hoc Group on ISDN-Satellite Matters during 1990–1992. Currently he is the Chairman of the Working Group on New Technologies in the ITU Intersector Coordinating Group (ICG) on Satellite Matters. Dr. Chitre was a programme manager during 1990 and 1991 on a contract from INTELSAT on systems studies on satellite communications systems architectures for ISDN and broadband ISDN systems. Currently he is the technical manager of the DoD Contract on ATM via satellite demonstration and the programme manager for the INTELSAT contract on analysis and top-level specification of INTELSAT ISDN subnetworks and SDH compatible transport network. Department manager for ISDN/Data Communications in the Network Technology Division of COMSAT Laboratories. His responsibilities include managing the implementation of next generation telecommunication systems for fixed and mobile satellite systems. Current projects include the development of a high data rate gateway switch that provides for the

Key issues regarding the operation of the broadband integrated services digital network (BISDN) via satellite are presented herein. The specific issues, challenges, and their resolutions are detailed. In particular, the impact of error characteristics and propagation delay on the operation of BISDN via satellite is discussed. Solutions are presented for removing adverse effects and providing high-quality service to users of BISDN via satellite.

关键词： ATM BISDN

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HYBRID SATELLITE AND TERRESTRIAL NETWORKS

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INTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS 1994年第3期12卷 313-327页

作者： CHITRE, DM SHYY, DJ EPHREMIDES, A GUPTA, S COMSAT Laboratories 22300 Comsat Drive Clarksburg MD 20871–9475 USA. Received his B.Sc. from the University of Bombay India an M.A. in mathematics from the University of Cambridge U.K. and a Ph.D. in physics from the University of Maryland. He is currently an Associate Executive Director of the Network Technology Division at COMSAT Laboratories. He has been involved in research and development activities in ISDN VSAT networks data communications and network systems and architectures. Prior to his current positions Dr. Chitre was a Principal Scientist in the Network Technology Division at COMSAT Laboratories. Dr. Chitre joined COMSAT Laboratories in 1980. He has made major contributions to the analysis and architecture of data communication ISDN and BISDN via satellite. Dr. Chitre directs and participates in the international and national standards activities in ISDN BISDN and data communication as they apply to satellite communication. He was Chairman of the Working Group on Protocols and Network Timing Function of the CCIR/CCITT Joint Ad Hoc Group on ISDN/Satellite Matters during 1990–1992. Currently he is the Chairman of the Working Group on New Technologies in the ITU Intersector Coordinating Group (ICG) on Satellite Matters. Dr. Chitre was a programme manager during 1990 and 1991 on a contract from INTELSAT on systems studies on satellite communications systems architectures for ISDN and broadband ISDN systems. Currently he is the technical manager of the DoD Contract on ATM via satellite demonstration and the programme manager for the INTELSAT contract on analysis and top-level specification of INTELSAT ISDN subnetworks and SDH compatible transport network. Received the B.S. degree in electrical engineering from national Chiao-Tung University Hsin-Chu Taiwan in 1983 and the M.S. and Ph.D. degrees in electrical engineering from Georgia Institute of Technology Atlanta GA in 1986 and 1990 respectively. From June 1987 to October 1987 he worked for the Department of Neurology Emory Univers

The role of satellite communications in networks that provide new services, such as frame relay and multimedia, is investigated. Both passive and active (on-board switching/processing) satellite systems are considered. Novel techniques are developed for each system to demonstrate, via detailed analysis and simulation, how the communications bandwidth agility of multipoint/broadcast satellite channels, and the on-board switching/processing, makes it feasible to provide these new services via hybrid satellite and terrestrial networks in a resource-efficient manner.

关键词： HYBRID NETWORKS ON-BOARD PROCESSING FRAME RELAY

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AN INVESTIGATION ON THE FINE DEFECT STRUCTURE OF COCRTA/CR MAGNETIC THIN-FILMS

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JOURNAL OF APPLIED PHYSICS 1993年第1期73卷 418-421页

作者： WONG, BY SHEN, Y LAUGHLIN, DE Data Storage System Center Department of Materials Science and Engineering Carnegie Mellon University Pittsburgh Pennsylvania 15213

The fine defect structure inside the CoCrTa grains in a CoCrTa/Cr bilayer film has been investigated by high-resolution transmission electron microscopy. A high density of stacking faults bound by partial dislocations has been observed. The origin of these stacking faults and the nucleation and growth of CoCrTa on Cr columns have been discussed. It is suggested the surface morphology of the Cr column could play an important role in determining the number of CoCrTa nuclei and consequently the size of the individual CoCrTa crystallographic variants. In addition, plates of face-centered cubic CoCrTa separating the hexagonal-close-packed regions have been found and we believe that the existence of these plates could lead to coercivity enhancement.

关键词： CHROMIUM ALLOYS COBALT ALLOYS TANTALUM ALLOYS TERNARY ALLOYS CHROMIUM BILAYERS THIN FILMS DEFECT STRUCTURE TRANSMISSION ELECTRON MICROSCOPY COERCIVE FORCE

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