检索结果-内蒙古大学图书馆

IEEE Conference on Vehicular Technology (VTC)

作者： W. Zhuang P.A. Goud W.A. Krzymien Department of Electrical & Computer Engineering University of Waterloo Waterloo ONT Canada Telecommunications Research Laboratory Edmonton AB Canada

In this paper, adaptive channel equalization is investigated in order to reduce the bit error rate of trellis-coded continuous-phase frequency shift keying (CPFSK) in an indoor radio environment. A new equalizer structure is proposed, which makes use of fractionally spaced soft-decision signal samples instead of symbol-spaced hard decisions on transmitted symbols in the decision feedback loop, in order to remove the intersymbol interference (ISI) resulting from the frequency-selective fading channel.< >

关键词： Adaptive equalizers Indoor radio communication Bit error rate Intersymbol interference Envelope detectors Decision feedback equalizers Digital modulation Radio frequency Delay Baseband

来源：评论

学校读者我要写书评

暂无评论

The effects of transmitter filtering on the performance of direct sequence spread spectrum multiple access systems

The effects of transmitter filtering on the performance of d...

引用

IEEE International Symposium on Spread Spectrum Techniques and Applications

作者： T. Ikegami M.B. Pursley Communications Research Laboratory Ministry of Posts and Telecommunications Kashima Ibaraki Japan Department of Electrical and Computer Engineering Clemson University Clemson SC USA

The effects of filtering in transmitters on the bit error performance of a binary asynchronous direct sequence spread spectrum communication system are examined in a multiple access environment. computer simulations are carried out to evaluate the effects of non-linear phase Chebyshev and Butterworth filters and linear phase Bessel, Gauss and Nyquist roll-off filters. The performance degradation of the system is compared and discussed in terms of the BT product of the filter or the transmitted spectrum.< >

关键词： Filtering Spread spectrum communication Radio transmitters Band pass filters computer simulation Gaussian noise Signal to noise ratio Chebyshev approximation Nonlinear filters Gaussian processes

来源：评论

学校读者我要写书评

暂无评论

Utilization of torque wheels for active damping of flexible manipulators

Utilization of torque wheels for active damping of flexible ...

引用

IEEE International Conference on Robotics and Automation (ICRA)

作者： F. Khorrami A.A. Gomez M.D. Hills Polytechnic University School of Electrical Engineering 4 Computer Science Control/Robotics Research Laboratory Brooklyn NY USA Bernoulli Optical Systems Company Danbury CT USA Control/Robotics Research Laboratory (CRRL) School of Electrical Engineering 4 Computer Science University of California Brooklyn NY USA

Utilization of inertial actuators, such as torque wheels, for vibration damping of a single-link flexible manipulator is considered. The torque wheel is mounted at the end effector of the manipulator to provide a bending moment at the tip for vibration suppression and pointing purposes. The torque exerted by the torque wheel at the end-effector of the manipulator is achieved through controlling the velocity of the torque wheel. A decentralized control scheme is advocated in this paper for slewing and vibration suppression. The local loop around the torque wheel is closed through feedback of the accelerometer signal at the tip. Experimental results are provided to show the effectiveness of the proposed method for end-effector positioning of flexible-link manipulators. Although the experimental results reported are for a single-link flexible manipulator, the results are applicable to the multi-link case. It may be shown that the dynamics from the voltage input to the torque wheel mounted at the tip to the tip position is minimum phase and hence invertible given that an inner-loop controller has been applied to stabilize the rigid-body motion.< >

关键词： Wheels Damping Torque control Manipulator dynamics Actuators End effectors Velocity control Distributed control Vibration control Feedback loop

来源：评论

学校读者我要写书评

暂无评论

Vibration suppression of unknown flexible payloads using a wrist mounted force/torque sensor for remote manipulator systems

Vibration suppression of unknown flexible payloads using a w...

引用

IEEE International Conference on Robotics and Automation (ICRA)

作者： S. Jain F. Khorrami Control/Robotics Research Laboratory (CRRL) School of Electrical Engineering & Computer Science Five Metrotech Center Polytechnic University Brooklyn NY USA

The problem of control design for robotic arms manipulating unknown flexible payloads is considered. control design based on neglecting the internal dynamics of the payload will result in degraded performance, increased task execution time, and even failure in performing tasks. At the same time, the characteristics of payloads to be handled vary with application. These considerations make it impractical to outfit the payload with sensors. A novel scheme utilizing a force/torque sensor at the wrist of the manipulator is introduced. A controller utilizing the wrist torque feedback from the sensor is designed as a function of parameters of the payload dynamics. An adaptive scheme for online identification of these parameters and adaptation of controller parameters is discussed. The scheme is implemented on a single-link manipulator carrying a flexible unknown payload. Experimental results validate the fact that the adaptive control maintains a robust performance for high speed slewing and varying payloads.< >

关键词： Payloads Wrist Sensor phenomena and characterization control design Manipulator dynamics Adaptive control Robots Arm Degradation Force sensors

来源：评论

学校读者我要写书评

暂无评论

H/sub /spl infin// control and estimation problems with delayed measurements: state space solutions

H/sub /spl infin// control and estimation problems with dela...

引用

American control Conference (ACC)

作者： K.M. Nagpal R. Ravi Electrical & Computer Engineering Department University of Iowa Iowa IA USA GE Cor rate Research & Development Control Systems and Electronic Technologies Laboratory Schenectady NY USA

Necessary and sufficient conditions for existence of estimators and controllers meeting desired H/sub /spl infin// performance criterion are given for the case where the finite sensor delays exist. A complete characterization of such controllers is also presented. The necessary and sufficient conditions are computable and are framed in terms of two algebraic Riccati equations and one finite-horizon Riccati differential equation. The controllers and estimators that are obtained here have a linear periodic structure and are easily implementable. At the foundation of these results lies a modified Nehari problem, the state space solution for which may be of independent interest.

关键词： Delay estimation State estimation State-space methods Riccati equations Sufficient conditions Differential equations control systems Sensor phenomena and characterization Differential algebraic equations Periodic structures

来源：评论

学校读者我要写书评

暂无评论

An adaptive fuzzy neural based controller and its application to smart structures

An adaptive fuzzy neural based controller and its applicatio...

引用

American control Conference (ACC)

作者： I.J. Zeonoun F. Khorrami CRRL Polytechnic Univ. Brooklyn NY USA Control Robotacs Research Laboratory CRRL School of Electrical Engineering Computer Science Six Metrotech Center Polytechnic University Brooklyn NY USA

This paper introduces a fuzzy neural based adaptive controller for simultaneous stabilization and robust performance of a family of plants. The family of plants may be attained from linearization of a nonlinear plant around different operating points or large parameter variations in a given plant. The main idea is to design a sequence of controllers corresponding to the different plants utilizing any standard control design. Thereafter, the obtained controllers will form the basis of the knowledge base of a fuzzy controller capable of deriving a desired crisp output through its inference engine. A neural network is utilized to derive a fuzzy model of the plant and to generate the rule base for the fuzzy logic controller through training. The effectiveness of this new scheme is verified on a smart structure with piezoceramic sensors and actuators.

关键词： Programmable control Adaptive control Fuzzy control Intelligent structures Fuzzy logic Robust control control design Engines Neural networks Fuzzy neural networks

来源：评论

学校读者我要写书评

暂无评论

Adaptive channel precoding for slowly fading channels

Adaptive channel precoding for slowly fading channels

引用

IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC)

作者： T. Zhuang W.A. Krzymein P.A. Goud Department of Electrical & Computer Engineering University of Waterloo Waterloo ONT Canada Dept. of Electr. & Comput. Eng. Waterloo Univ. Ont. Canada Telecommunications Research Laboratory Edmonton AB Canada

The bit error rate (BER) performance of a mobile or personal radio digital communications system at a high bit rate can be increased significantly by intersymbol interference (ISI) due to multipath propagation. In this paper, a novel adaptive channel precoder is proposed to improve the system performance with-out increasing the complexity of the portable unit. In the forward link, both the amplitude and phase of the signal carrier are predistorted at the transmitter of the base station, so that the signal received at the portable unit is ISI free (in the ideal case). The precoding is based on channel information estimated (from the reverse link) at the receiver of the base station. computer simulation results demonstrate that, over a two-path Rayleigh fading channel, differential QPSK with the precoder has significantly lower BER values than those with a conventional decision feedback equalizer (DFE), because the precoder is not subject to error propagation.

关键词： Fading Bit error rate Intersymbol interference Base stations Decision feedback equalizers Digital communication Bit rate System performance Radio transmitters computer simulation

来源：评论

学校读者我要写书评

暂无评论

Fuzzy based adaptive control for flexible-link manipulators actuated by piezoceramics

Fuzzy based adaptive control for flexible-link manipulators ...

引用

IEEE International Conference on Robotics and Automation (ICRA)

作者： I. Zeinoun F. Khorrami Sch. of Electr. Eng. & Comput. Sci. Polytechnic Univ. Brooklyn NY USA Control/Robotics Research Laboratory (CRRL) School of Electrical Engineering & Computer Science Six Metrotech Center Polytechnic University Brooklyn NY USA

This paper presents an adaptive control scheme based on a fuzzy logic algorithm and its application to end-effector positioning of flexible-link manipulators. Here, a fuzzy based adaptive controller is considered due to its simplicity and the fact that it does not require expressing the controller in terms of the system parameters, as it is necessary in the case of self-tuning regulators. This controller is based on a functional fuzzy model where the consequents are crisp functions represent controllers designed for different operating regimes. The premise is constituted by the fuzzy subsets corresponding to the process parameters estimated in real time. The effectiveness of this new scheme is verified on a clamped free beam and a single-line flexible arm instrumented with piezoceramic sensors and actuators. It is shown that robust performance may be achieved in face of large parameter variations.< >

关键词： Fuzzy control Adaptive control control systems Fuzzy logic Fuzzy systems Programmable control Parameter estimation Instruments Piezoelectric materials Actuators

来源：评论

学校读者我要写书评

暂无评论

THE CALLING(SM) NETWORK - A GLOBAL WIRELESS COMMUNICATION-SYSTEM

引用

INTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS 1994年第1期12卷 45-61页

作者： TUCK, EF PATTERSON, DP STUART, JR LAWRENCE, MH Calling Communications Corporation. 1900 West Garvey Ave South. Suite 200 West Covina CA 91790 USA. Chairman of Calling Communications Corporation. He is also the Managing Director of Kinship Venture Management Inc. the general partner of Kinship Partners 11 and a General Partner of Boundary the general partner of The Boundary Fund. As a venture capitalist he has founded or participated in founding several telecommunications companies including Calling Communications Corporation Magellan Systems Corporation manufactures of Global Positioning System receivers Applied Digital Access manufacturer of DS-3 test access and network performance monitoring equipment Endgate Technology Corporation specialists in satellite phased array antennas and Poynting Systems Corporation. now a division of Reliance Corporation manufacturers of fibre optic transport equipment. He was a founder of Kebby Microwave Corporation where he invented the first solid-state. frequency-modulated commercial microwave link system. The company was acquired by ITT Corporation where he rose to the position of V.P. and Technical Director of ITT North America Telecommunications Inc. Subsequently he was V.P. of Marketing and Engineering at American Telecommunications Inc. (ATC). He was founding Director of American Telecom Inc. a joint venture between ATC and Fujitsu and has served on more than 20 boards of directors including those of three public companies. He has authored articles on microwave engineering and telephone signalling and was a contributor to Reference Data For Radio Engineers. He is a graduate of the University of Missouri at Rolla where he was later awarded an honorary Professional degree and serves on its Academy of Electrical Engineering. Mr Tuck is a Senior Member of the IEEE a Fellow of the Institution of Engineers (Australia) a Professional Member of the AIAA and a registered professional engineer in three states. More than 25 years of experience in the telecommunications industry where he has been responsibl

There is a very large demand for basic telephone service in developing nations, and remote parts of industrialized nations, which cannot be met by conventional wireline and cellular systems. This is the world's largest unserved market. We describe a system which uses recent advances in active phased arrays, fast-packet switching technology, adaptive routeing, and light spacecraft technology, in part based on the work of the Jet Propulsion laboratory and on recently-declassified work done on the Strategic Defense Initiative, to make it possible to address this market with a global telephone network based on a large low-Earth-orbit constellation of identical satellites. A telephone utility can use such a network to provide the same modern basic and enhanced telephone services offered by telephone utilities in the urban centres of fully-industrialized nations. Economies of scale permit capital and operating costs per subscriber low enough to provide a service to all subscribers, regardless of location, at prices comparable to the same services in urban areas of industrialized nations, while generating operating profits great enough to attract the capital needed for its construction. The bandwidth needed to support the capacity needed to gain these economies of scale requires that the system use K(alpha)-band frequencies. This choice of frequencies places unusual constraints on the network design, and in particular forces the use of a large number of satellites. Global demand for basic and enhanced telephone service is great enough to support at least three networks of the size described herein. The volume of advanced components, and services such as launch services, required to construct and replace these networks is sufficient to propel certain industries to market leadership positions in the early 21st Century.

关键词： LOW EARTH ORBIT SATELLITE COMMUNICATIONS FAST PACKET SWITCHING EARTH FIXED CELLS ADAPTIVE ROUTEING LIGHT SPACECRAFT K(A) BAND PHASED-ARRAY ANTENNAS

来源：评论

学校读者我要写书评

暂无评论

ANALYSIS OF A MOVABLE BOUNDARY ACCESS TECHNIQUE FOR A MULTISERVICE MULTIBEAM SATELLITE SYSTEM

引用

INTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS 1994年第3期12卷 299-312页

作者： BOHM, S ELHAKEEM, AK MURTHY, KMS HACHICHA, M KADOCH, M Department of Electrical and Computer Engineering Concordia University 1455 De Maisonneuve Blvd. West Montreal H3A 1M8 Canada Was born in Montreal Canada on 14 September 1966. He received the B. Eng. degree in electrical engineering from Concordia University Montreal Canada in 1989. He is at present completing the M.A.Sc. degree in electrical engineering at Concordia University. (S'75–S'79–M'79–SM'86) received the Ph.D. degree from Southern Methodist University Dallas TX in 1979. He spent the next two years working as a Visiting Professor in Egypt after which he moved to Ottawa Canada in 1982. He assumed teaching and research positions in Carleton and Manitoba Univerities and later moved to Concordia University Montreal Canada in 1983 where he is now a Professor in the Electrical and Computer Engineering Department. He has published numerous papers in IEEE and international journals in the areas of spread spectrum and networking. He is a well-known expert in these areas and serves as a consultant to many companies. His current research interests include wide-band metropolitan networks switching architectures and performance of on-board multibeam satellites acquisitionless CDMA networks code distribution and orthogonalization of CDMA signals responsive congestion control for ATM-based networks ARQ techniques and investigation of the novel SUGAR CDMA systems in fading channels. Dr. Elhakeem is a Senior Member of the Canadian Electrical Engineering Society and Armed Forces Association. He has chaired numerous technical sessions in IEEE Conferences was the Technical Program Chairman for IEEE Montech 1986 Montreal Canada. Dr. Elhakeem is the key guest editor of theIEEE Journal of Selected Areas in Communicationsfor the May June issues 1993 covering CDMA networks. Advanced Technology & Networks VISTAR Telecommunications Inc. Ottawa Ontario K1G 3J4 Canada . He is ITU's Specialist Consultant and Chief Advisor for a number of ITU/UNDP projects including VSATs Rural Networks Digital Broadc

In this paper, the performance of a new movable boundary accessing (MBA) technique for future integrated services multibeam satellite systems is studied. The multiservice environment considered includes both asynchronous and isochronous traffic consisting of video, voice, file transfer and interactive data. The movable boundary access technique proposed here will maximize the utilization of the up-link frame capacity. It is shown that the potential user population is substantially increased with the use of a moving boundary policy with minimal overhead.

关键词： MOVABLE BOUNDARY ACCESS TECHNIQUE MF-TDMA DAMA MULTIBEAM SATELLITE

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：