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Annual Northeast Bioengineering Conference

作者： Z. Markowitz M.H. Loew Biomedical Engineering Program Department of Electrical and Computer Engineering George Washington University Washington D.C. DC USA

Estimation of volume, surface area, area, length and number in stereology is based on a manual count of the number of intersections between the feature of interest and a specific low-resolution geometrical test probe. It is usually a tedious and imprecise process, hut benefits from the user's ability to identify the feature of interest. In computer-based stereology, by contrast, a high-resolution test probe is used, generally yielding greater precision but suffering from imperfection of the automated classification. The trade-offs between manual and computer-based stereology are introduced and the conditions under which each is advantageous are defined.

关键词： Labeling Probes Testing Image processing Biology computing Pixel computer errors Humans Concurrent computing Biomedical computing

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The trade-offs between manual and computer-based stereology/classification: application to estimates of volume fraction

The trade-offs between manual and computer-based stereology/...

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Annual International Conference of the IEEE engineering in Medicine and Biology Society (EMBC)

作者： Z. Markowitz M.H. Loew Biomedical Engineering Program Department of Electrical and Computer Engineering George Washington University Washington D.C. DC USA

Estimation of volume or the ratio of volumes in an image requires both mensuration and classification. The former is achieved through stereology - a set of techniques that estimate such parameters as area, volume, surface area, length, and number. Classification is achieved by extracting features that capture discriminating information (e.g., about tissue type). Both stereology and classification can be performed either manually or by computer. Manual techniques for the combination are based on coarse point counting (low resolution), but assumed perfect pixel classification. computer-based methods, on the other hand, rely on very fine point counting but in general suffer from imperfect pixel classification. This paper examines the interaction between manual and image processing-based approaches; in particular, we present a measure that combines the classification and measurement errors. Estimation of the variance is used to define the conditions under which each method is and is not advantageous despite its underlying error. This allows the user to choose a method that optimizes overall performance, given the human and machine capabilities available. Illustrations are given of cases in which each method can be preferable, as measured by the variance of the estimate of the performance that was inferred from the measurement.

关键词： Application software Parameter estimation Data mining Feature extraction Manuals Particle measurements Measurement errors Estimation error Optimization methods Humans

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Voice transmission over all-IP tandem links

Voice transmission over all-IP tandem links

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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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Artificial neural network-based pharmacodynamic population analysis in chronic renal failure

Artificial neural network-based pharmacodynamic population a...

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International Joint Conference on Neural Networks (IJCNN)

作者： A.E. Gaweda A.A. Jacobs M.E. Brier J.M. Zurada Kidney Disease Program Louisville USA Department of Veteran Affairs Kidney Disease Program Department of Electrical and Computer Engineering University of Louisville Louisville KY USA

An artificial neural network (ANN)-based approach to pharmacodynamic population analysis presented. In pursuit of an optimal and cost-effective strategy for drug dosing in patients with renal failure, an ANN is applied to perform drug-dose-effect modeling. Such a model allows for versatile prediction of the response to the drug at the effect site and, subsequently, for adjusting the dosing regimen.

关键词： Artificial neural networks Failure analysis Intelligent networks Drugs Iron Diseases Predictive models Medical treatment Personnel Laboratories

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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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Intersubband Transitions in InxGa1-xAs/AlGaAs Multiple Quantum Wells for Long Wavelength Infrared Detection

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MRS Online Proceedings Library 2003年第1期744卷 1-6页

作者： Workman, Clayton L. Wang, Zhiming Ma, Wenquan George, Christi E. Panneer Selvam, R. Salamo, Gregory J. Zhou, Qiaoying Omar Manasreh, M. Center for Semiconductor Physics in Nanostructures (C-SPIN) and the Microelectronics-Photonics Program University of Arkansas Fayetteville USA Department of Electrical and Computer Engineering University of New Mexico Albuquerque USA

We report on intersubband transitions in InxGa1-xAs/AlGaAs multiple quantum wells (MQWs) grown by molecular beam epitaxy. The conduction band offset for this material system is larger than that of the well known GaAs/AlGaAs system, thus making it possible to design, grow, and fabricate quantum well infrared photodetectors operational beyond the 14 μm spectral region with minimized dark current. We have grown InxGa1-xAs/AlGaAs MQWs with indium compositions ranging from x = 0.08 to 0.20 verified by in situ RHEED oscillations, band offset measurements, and high-resolution X-ray diffraction. Band-to-band transitions were verified by photoluminescence measurements, and intersubband transitions were measured using Fourier transform infrared (FTIR) spectroscopy. Due to the high strain and introduction of dislocations associated with the high indium content, wells with indium compositions above ∼ 0.12 did not result in intersubband transitions at silicon doping levels of 2×1018 cm-3. A thick linear graded InxGa1-xAs buffer was grown below the MQW structures to reduce the strain and resulting dislocations. Intersubband transitions were measured in InxGa1-xAs wells with indium compositions of x = 0.20 and greater when grown on top of the linear graded buffer. In addition to these results, FTIR measurements on InGaAs/AlGaAs MQW multi-color, long-wavelength infrared detector structures are reported.

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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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Zero-forcing multiuser detection in CDMA systems using long codes

Zero-forcing multiuser detection in CDMA systems using long ...

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IEEE Conference and Exhibition on Global Telecommunications (GLOBECOM)

作者： C.B. Ribeiro M.L.R. de Campos P.S.R. Diniz Electrical Engineering Program and Department of Electronics and Computer Engineering Federal University of Rio de Janeiro (COPPE-EE) Rio de Janeiro Rio de Janeiro Brazil

In this article, we show that a code division multiple access (CDMA) system employing long codes can be interpreted as a multiple input multiple output system where the transmit filters are time-varying. We derive conditions for existence of zero-forcing equalizers and verify through simulations that these conditions are useful guidelines for the design of appropriate solution in the presence of noise. Compared to similar works in the literature, the derived conditions allow a reduction in the length of the equalizer filters, while imposing no constraints on the channel order.

关键词： Multiuser detection Multiaccess communication MIMO Filter bank Equalizers Communication systems Downlink Channel bank filters Intersymbol interference Time varying systems

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Mixed-excited phonetic vocoding at 265 bps

Mixed-excited phonetic vocoding at 265 bps

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International Conference on Acoustics, Speech, and Signal Processing (ICASSP)

作者： R. da S Maia R.J. da R Cirigliano D. Rojtenberg F.G.V. Resende Electrical Engineering Program/COPPE Federal University of Rio de Janeiro Rio de Janeiro Brazil Electrical Engineering Program/COPPE Dept. of Electronics and Computer Science/EPoli Federal University of Rio de Janeiro Rio de Janeiro RJ Brazil

In this paper a phonetic vocoder which synthesizes speech using mixed excitation is presented. The encoder carries out HMM-based speech recognition and pitch analysis, whereas the decoder performs parameter extraction from HMM and builds a mixed excitation using pitch and bandpass voicing strengths. The vocoder at an average bit rate of 265 bit/s reaches good degree of intelligibility, while the use of mixed excitation significantly improves the speech quality with no increase of bit rate when compared with the conventional binary excitation pulse train/random noise.

关键词： Vocoders Speech synthesis Bit rate Speech recognition Speech analysis Performance analysis Decoding Parameter extraction Hidden Markov models Speech enhancement

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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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