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Asilomar Conference on Signals, Systems & computers

作者： Bo Wei J.D. Gibson Department of Electrical Engineering Southern Methodist University Dallas TX USA Media Arts Technology Program and Electrical & Computer Engineering University of California Santa Barbara CA USA

We investigate the issues in voice communications using IP over tandem connections of wireline and wireless links with the goal of determining end-to-end system performance. We study the particular example of using G.711 speech coding in the backbone wireline network and adaptive multi-rate (AMR) speech coding in a wireless LAN tandem network and study the impact of specific methods of adaptive re-encoding, error concealment, error control coding, and network protocol design to deliver the desired end-to-end quality of service. In addition to simulation results and objective speech quality measures, we present estimation-theoretic and information-theoretic analyses for the tandem packet loss link connections.

关键词： Speech coding programmable control Adaptive control Error correction Speech analysis System performance Spine Adaptive systems Wireless LAN Wireless application protocol

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Channel Estimation and Data Detection for MIMO-OFDM Systems

Channel Estimation and Data Detection for MIMO-OFDM Systems

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IEEE Global Telecommunications Conference GLOBECOM'03

作者： Yue, Jiang Kim, Kyeong Jin Gibson, Jerry D. Iltis, Ronald A. Department of Electrical Engineering Southern Methodist University Dallas TX 75275 United States Nokia Research Center 6000 Connection Dr. Irving TX 75039 United States Media Arts and Technology Program Elec. and Computer Engineering Univ. of California Santa Barbara Santa Barbara CA 93106-6065 United States Department of Electrical Engineering University of California Santa Barbara CA 93106-9560 United States

The use of multiple antennas at both the transmitter and receiver can significantly increase the channel capacity. These systems are called the multiple-input multiple-output (MIMO) systems. By using orthogonal frequency division multiplexing (OFDM) transmission techniques, the MIMO-OFDM system can achieve high spectral efficiency, which makes it an attractive candidate for high-data-rate wireless applications. In this paper, we propose a convolutionally coded MIMO-OFDM system with EM-based channel estimation and a QRD-M data detection algorithm. In our systems, one training symbol is transmitted from each transmit antenna for the MEMO channel estimation at the receiver. With the channel estimates available, we apply the QRD-M algorithm on the estimated channel matrix for suboptimal data detection with reasonable computational cost. The bit error rate (BER) and packet error rate (PER) performance of the MIMO-OFDM systems are compared. In the simulations, the bit error rate performance of our systems is 9 (or 5) dB better than that of uncoded (or coded) BLAST systems.

关键词： Orthogonal frequency division multiplexing

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A multi-paradigm simulator for simulating complex adaptive supply chain networks

A multi-paradigm simulator for simulating complex adaptive s...

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Simulation Winter Conference

作者： Pathak Dilts Biswas Management of Technology Program (EECS) Vanderbilt University Nashville TN USA Department of Electrical Engineering and Computer Science Vanderbilt University Nashville TN USA

This paper introduces a multi-paradigm dynamic system simulator based on discrete time and discrete event formalism for simulating a supply chain as a complex adaptive system. Little is known about why such a diversity of supply chain structures exist. Simulating dynamic supply chain networks over extended periods using the multi-paradigm dynamic system simulator allows us to observe the emergence of different structures. The simulator is implemented using a software agent technology, where individual agents represent firms in a supply chain network. In this paper, we present an example scenario run on the simulator and the preliminary results that have been observed. This multi-paradigm tool provides a valuable investigation instrument for real life supply chain problems.

关键词： Adaptive systems Supply chains Vehicle dynamics Discrete event simulation Manufacturing industries technology management Software agents Supply chain management Procurement computer industry

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Channel estimation and data detection for MIMO-OFDM systems

Channel estimation and data detection for MIMO-OFDM systems

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IEEE Conference and Exhibition on Global Telecommunications (GLOBECOM)

作者： Jiang Yue Kyeong Jin Kim J.D. Gibson R.A. Iltis Department of Electrical Engineering Southern Methodist University Dallas TX USA Nokia Research Center Irving TX USA Media Arts and Technology Program and Electrical & Computer Engineering University of California슠Santa Barbara Santa Barbara CA USA Department of Electrical and Computer Engineering University of California Santa Barbara CA USA

The use of multiple antennas at both the transmitter and receiver can significantly increase the channel capacity. These systems are called the multiple-input multiple-output (MIMO) systems. By using orthogonal frequency division multiplexing (OFDM) transmission techniques, the MIMO-OFDM system can achieve high spectral efficiency, which makes it an attractive candidate for high-data-rate wireless applications. In this paper, we propose a convolutionally coded MIMO-OFDM system with EM-based channel estimation and a QRD-M data detection algorithm. In our systems, one training symbol is transmitted from each transmit antenna for the MIMO channel estimation at the receiver. With the channel estimates available, we apply the QRD-M algorithm on the estimated channel matrix for suboptimal data detection with reasonable computational cost. The bit error rate (BER) and packet error rate (PER) performance of the MIMO-OFDM systems are compared. In the simulations, the bit error rate performance of our systems is 9 (or 5) dB better than that of uncoded (or coded) BLAST systems.

关键词： Channel estimation MIMO Bit error rate Receiving antennas Transmitting antennas OFDM Transmitters Channel capacity Convolutional codes Detection algorithms

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Realization adaptive strategies and a comparison of Fourier bandwidth, Shannon bandwidth, and Campbell bandwidth

Realization adaptive strategies and a comparison of Fourier ...

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Data Compression Conference (DCC)

作者： Wenye Tang Tao He J.D. Gibson Globespan Virata Inc. Red Bank NJ USA Electrical Engineering Department Southern Methodist University Dallas TX USA Media Arts and Technology Program & Electrical and Computer Engineering University of California at Santa Barbara Santa Barbara CA USA

In 1960, Campbell derived a quantity that he defined as the coefficient rate of a random process that involves the process spectral entropy. However, no potential applications of the coefficient rate were identified. Two new derivations of Campbell's rate coefficient rate are presented. One derivation solidifies the interpretation of this quantity as a coefficient rate and allows definition of an effective bandwidth for the process. The second derivation implies a new approach for realization adaptive source compression. The coefficient rate can be used for realization adaptive coefficient selection in a sequence of source representations. Furthermore, the effective bandwidth is designated as Campbell bandwidth and contrasted with Fourier bandwidth and Shannon bandwidth. Several specific examples are presented that illustrate the differences among the three quantities.

关键词： Bandwidth Entropy Random processes Electronic mail Image coding Speech processing Discrete cosine transforms Energy measurement Helium Codes

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Diversity-embedded space-time codes

Diversity-embedded space-time codes

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IEEE Conference and Exhibition on Global Telecommunications (GLOBECOM)

作者： S.N. Diggavi N. Al-Dhahir A.R. Calderbank School of Computer and Communication Sciences Swiss Federal Institute of Technology Lausanne Switzerland Department of Electrical Engineering University of Technology Dallas TX USA Program in Applied and Computational Mathematics Princeton University Princeton NJ USA

Rate and diversity impose a fundamental trade-off in space-time coding. High-rate space-time codes come at a cost of lower diversity, and high reliability (diversity) implies a lower rate. We explore a different point of view where we design high-rate space-time codes that have a high-diversity code embedded within them. This allows a form of communication where the high-rate code opportunistically takes advantage of good channel realizations whereas the embedded high-diversity code ensures that at least part of the information is received reliably. We explore this point of view with design issues, along with some preliminary progress on code constructions and some information-theoretic considerations.

关键词： Space time codes Rayleigh channels Costs Transmitting antennas Transmitters Space technology Mathematics Wireless communication Error probability Time division multiplexing

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Holistic approach for technology entrepreneurship education in engineering

Holistic approach for technology entrepreneurship education ...

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Frontiers in Education (FIE) Conference

作者： D.F. Barbe S.A. Magids K.S. Thornton Maryland Technology Enterprise Institute and the Department of Electrical and Computer Engineering University of Maryland College Park MD USA Maryland Technology Enterprise Institute University of Maryland College Park MD USA Maryland Technology Enterprise Institute Hinman CEOs Program University of Maryland College Park MD USA

This paper discusses a comprehensive strategic approach being carried out by the A. James Clark School of engineering at the University of Maryland for facilitating technology entrepreneurship for undergraduate and graduate students as well as faculty in diverse technical disciplines. Our objectives are to foster an increasingly entrepreneurial culture that helps students and faculty understand the fundamentals and feasibility of forming technology enterprise, to help them establish and manage sustainable ventures and to accelerate commercialization of technologies developed on campus.

关键词： Educational technology Innovation management Business Educational institutions technology management engineering management Robustness Acceleration Commercialization engineering students

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Human systems integration and advanced technology in engineering department workload and manpower reduction

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NAVAL ENGINEERS JOURNAL 2003年第1期115卷 57-65页

作者： Lively, KA Seman, AJ Kirkpatrick, M KENNETH A. LIVELY graduated from the University of Colorado with a BS in applied mathematics and an MS in mathematics in 1976 and from the Massachusetts Institute of Technology with an MS in electrical engineering and the degree ocean engineer in naval architecture and marine engineering in 1984. He retired from the U.S. Navy in 1989 after 23 years of service. Assignments included electrical officer on the USS Constellation (CV 64) project engineer for the DDG 51 machinery control system (NAVSEA) and DDG 51 Technical Director (NAVSEA). He was vice president of the PDI Division of Bird-Johnson Company from July 1989 to November 1998 where he managed various gas turbine and machinery controls related development projects. He joined Anteon Corporation's Systems Engineering Group as senior controls engineer in December 1998 where he provided technical support to the integrated power systems program (NAVSEA PMS 510) and managed the Office of Naval Research Afloat Laboratory. DR. MARK KIRKPATRICK is currently an independent consultant in human factors and work-load/manning analysis and modeling. He holds a Ph.D. degree in experimental psychology from The Ohio State University and has 34 years of experience in applied human factors. From 1982 through 2000 Dr. Kirkpatrick served as the senior vice president of Carlow International. Prior to joining Carlow in 1982 Dr. Kirkpatrick served as a member of the technical staff at North American Rockwell's Missiles Division and as a project director and vice president for Essex Corporation. His areas of expertise include workload simulation task analysis operator-in-the-loop simulation human performance experimentation statistical analysis and human factors T&E. He has directed and/or participated in human factors projects for the U.S. Navy U.S. Army NASA Department of Transportation the U.S. Nuclear Regulatory Commission and private industry. ANTHONY J. SEMAN III is the technical manager for the reduced ship's crew by virtual presence (RSVP) advanced technology d

Aboard current ships, such as the DDG 51, engineering control and damage control activities are manpower intensive. It is anticipated that, for future combatants, the workload demand arising from operation of systems under conditions of normal steaming and during casualty response will need to be markedly reduced via automated monitoring, autonomous control, and other technology initiatives. Current DDG 51 class ships can be considered as a manpower baseline and under Condition III typical engineering control involves seven to eight watchstanders at manned stations in the Central Control Station, the engine rooms and other machinery spaces. In contrast to this manning level, initiatives such as DD 21 and the integrated engineering plant (IEP) envision a partnership between the operator and the automation system, with more and more of the operator's functions being shifted to the automation system as manning levels decrease. This paper describes some human systems integration studies of workload demand reduction and, consequently, manning reduction that can be achieved due to application of several advanced technology concepts. Advanced system concept studies in relation to workload demand are described and reviewed including. Piecemeal applications of diverse automation and remote control technology concepts to selected high driver tasks in current DDG 51 activities. Development of the reduced ship's crew by virtual presence system that will provide automated monitoring and display to operators of machinery health, compartment conditions, and personnel health. The IEP envisions the machinery control system as a provider of resources that are used by various consumers around the ship. Resource needs and consumer priorities are at all times dependent upon the ship's current mission and the availability of equipment pawnbrokers.

关键词： Naval warfare

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Performance of a space-time block coded OFDM system

Performance of a space-time block coded OFDM system

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The Thirty-Sixth Asilomar Conference on Signals Systems and computers

作者： Yue, Jiang Gibson, Jerry D. Department of Electrical Engineering School of Engineering Southern Methodist University Dallas TX 75275 United States Media Arts Technology Program Electrical and Computer Engineering Univ. of California Santa Barbara Santa Barbara CA 93106-6065 United States

Combined with antenna diversity, space-time coding is an attractive candidate for high-rate transmission systems such as orthogonal frequency division multiplexing (OFDM) systems. In this paper, we propose space-time block coded OFDM systems that use training symbols coded by STBC. We use two training symbols at the beginning of each of two OFDM frames that are simultaneously transmitted from two corresponding transmit antennas. Based on the orthogonality of space-time block codes, we perform channel estimation by using training symbols, and compare to EM-based channel estimation methods. From the simulation results, we observe that our space-time block coding technique offers a good approach to channel estimation and better signal quality than the EM-based method.

关键词： Orthogonal frequency division multiplexing

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Adaptation of current signals with floating-gate circuits

Adaptation of current signals with floating-gate circuits

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作者： Pesavento, Alberto Horiuchi, Timothy Diorio, Chris Koch, Christof Department of Electrical Engineering California Institute of Technology Pasadena CA 91125 United States Department of Electrical and Computer Engineering University of Maryland College Park MD 20742 United States Department of Computer Science and Engineering University of Washington Seattle WA 98195-2350 United States Computation and Neural Systems Program California Institute of Technology Pasadena CA 91125 United States

In this paper we present a new, adaptive spatial-derivative circuit for CMOS image sensors. The circuit removes its offset as a natural part of its operation using a combination of electron tunneling and hot-electron injection to add or remove charge on a floating-gate of an auto-zeroing amplifier. We designed, fabricated and successfully tested a chip with the circuit. Test results show that the circuit reduces the offsets by more than an order of magnitude.

关键词： Image sensors

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