[1992] Conference Record of the Twenty-Sixth Asilomar Conference on Signals, Systems & Computers

26-28 Oct. 1992

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  • Analysis of DS/SSMA system with hard-limiting correlator over fading channels with impulsive noise

    Publication Year: 1992, Page(s):93 - 97 vol.1
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (244 KB)

    The performance of a DS/SSMA (direct-sequence spread-spectrum multiaccess) system with hard-limiting correlation receivers is analyzed over nonselective Rician fading channels with impulsive noise. More specifically, computation of the average bit-error probabilities of the DS/SSMA system have been accomplished in this paper by exact computation for short spreading sequences and by approximation f... View full abstract»

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  • Conference Record of The Twenty-Sixth Asilomar Conference on Signals, Systems and Computers (Cat. No.92CH3245-8)

    Publication Year: 1992
    Request permission for commercial reuse | PDF file iconPDF (20 KB)
    Freely Available from IEEE
  • Practical considerations for executing vision algorithms on parallel arrays

    Publication Year: 1992, Page(s):1021 - 1025 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (284 KB)

    It is shown that levels of performance claimed for vision algorithms can be overly optimistic if the computation time and communication time, both of which affect the schedule length of algorithms running on parallel arrays, are not quantified. Examples are given to show how the embedding technique and problem partitioning can affect communication time. When the number of computations exceeds the ... View full abstract»

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  • Performance evaluation of cyclic polyspectrum estimators

    Publication Year: 1992, Page(s):477 - 483 vol.1
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (472 KB)

    Results of analysis and computer simulations are used to compare two methods of estimating the cyclic polyspectrum. The computational requirements of the two methods are determined and compared. A cycle leakage phenomenon is explained and it is shown that, for a given amount of data, only one of the two methods can be modified to reduce this leakage, but at the cost of increased computations. Nume... View full abstract»

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  • Low-dimensional processing of still and moving images

    Publication Year: 1992, Page(s):1026 - 1030 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (356 KB)

    The Karhunen-Loeve procedure for the processing of still and moving images is considered. The formulation is presented in terms of the singular value decomposition, an approach which makes it possible to treat moderate sized ensembles of high-resolution images or large ensembles of low-resolution images. Applications of the technique to several test problems, including data generated by numerical ... View full abstract»

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  • A robust CMA adaptive array for multiple narrowband sources

    Publication Year: 1992, Page(s):35 - 39 vol.1
    Cited by:  Papers (2)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (312 KB)

    A new version of the CMA/LMS adaptive array (constant modulus algorithm with the least-mean-square algorithm) that recovers both the arrival angles and the signals from multiple narrowband sources is presented. The algorithm operates in two stages, to resolve problems of imperfect cancellation found in single-stage multiple-emitter CMA algorithms. An orthogonalized CMA loop finds and adapts the be... View full abstract»

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  • The wave packet transform (WPT) as applied to signal processing

    Publication Year: 1992, Page(s):484 - 487 vol.1
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (276 KB)

    The wave packet transform (WPT) is introduced. It uses the Weyl operator and wave packet functions, i.e., functions that are similar to wavelets, in a linear form to compute coefficients in a two-dimensional space of time and frequency. The importance of the Weyl operator in the WPT and its use with different wave packets are discussed. It is shown that the energetic form of the WPT, the wavepacke... View full abstract»

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  • A real-time multimedia system for video applications

    Publication Year: 1992, Page(s):1031 - 1036 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (496 KB)

    An embedded multimedia system is being constructed to provide high-quality video and audio processing capabilities for desktop multimedia workstations. This versatile JPEG-based system is capable of sustaining a throughput of 2-Mbyte/s compressed data rate, which is a necessary condition for studio quality video and audio at the CCIR 601 resolution. The main design challenge is to methodologically... View full abstract»

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  • A dynamically reconfigurable M-SIMD implementation architecture for large scale neural-digital hybrid processing

    Publication Year: 1992, Page(s):40 - 44 vol.1
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (356 KB)

    A modular, reconfigurable, parallel and linearly scalable hardware implementation architecture for realization of large scale neural networks, called the modular neural ring (MNR), has been developed, prototyped, and shown to be highly effective in hardware implementation of large scale neural computing models. The authors examine the possibility of extending the use of the architecture to vector ... View full abstract»

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  • Array processing in correlated noise fields using instrumental variables and subspace fitting

    Publication Year: 1992, Page(s):1147 - 1151 vol.2
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (344 KB)

    An improved technique for direction-of-arrival estimation of temporally correlated signals in the presence of spatially colored, but temporally uncorrelated, noise is presented. The method is particularly suited to applications in which the receiver bandwidth exceeds that of the emitter signals. A statistical performance analysis shows that the method nearly achieves the deterministic Cramer-Rao b... View full abstract»

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  • Performance analysis of the modified maximum likelihood sequence detector in the presence of data-dependent noise

    Publication Year: 1992, Page(s):961 - 964 vol.2
    Cited by:  Papers (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (252 KB)

    The use of a modified maximum-likelihood sequence detector (MLSD) in a data-dependent noise channel is proposed. A new error metric based on nonstationary transition-dependent noise characteristics is derived. Simplified error metrics are suggested to reduce complexity. Performance is analyzed, noting that the error rate can be derived from a chi-square distribution. Simulation results show that t... View full abstract»

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  • Spectral decomposition of time-frequency distribution kernels

    Publication Year: 1992, Page(s):488 - 492 vol.1
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (264 KB)

    It is shown that the singular-value decomposition (SVD) of the time-frequency kernels allows the expression of the time-frequency distributions in terms of weighted sum of smoothed pseudo Wigner-Ville distributions or modified periodograms, which are the two basic nonparametric power distributions for stationary and nonstationary signals, respectively. The windows appearing in the decomposition ta... View full abstract»

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  • Implementation of an all-digital DS-CDMA receiver-chip synchronization for an orthogonally coded cellular CDMA system

    Publication Year: 1992, Page(s):627 - 631 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (232 KB)

    The authors propose an all-digital code tracking scheme for a bandlimited cellular direct-sequence code-division-multiple-access (DS-CDMA) system, which uses bandlimited Nyquist chip pulse shaping and orthogonal coding. The code tracking loop has a decision-directed noncoherent structure to handle the orthogonally coded DS-CDMA signals. The performance of the tracking loop is derived analytically View full abstract»

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  • On the normalization of the step size in nonsymmetric stochastic gradient algorithms

    Publication Year: 1992, Page(s):876 - 880 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (332 KB)

    The normalization of the step size in the least-mean-square (LMS) algorithm allows easy control of the range of stable operation for the normalized step size in the normalized LMS (NLMS) algorithm, and also easy determination of the step size for maximum convergence speed. A generalized step size normalization for stochastic gradient algorithms in which the gradient vector differs from the data ve... View full abstract»

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  • Adaptive FIR filtering based on bounded error constraints

    Publication Year: 1992, Page(s):15 - 19 vol.1
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (356 KB)

    The performance of adaptive FIR algorithms in the presence of bounded disturbances, in particular, algorithms based on gradient mean squared error (MSE) estimators, gradient estimators with dead-zone thresholds, and set membership estimators, is examined. A simple example of the bursting phenomenon is given, and the algorithms and their properties are described. Analytical results on the performan... View full abstract»

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  • Ambiguity function for sonar

    Publication Year: 1992, Page(s):1127 - 1131 vol.2
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (300 KB)

    The authors present a new definition of ambiguity and illustrate its application to the study of passive localization of sources in deep ocean situations. The tool developed allows the study of the impact of all relevant parameters, including those relative to the physical medium as well as those pertinent to the instrumentation and signals involved. Particular attention is given to such factors a... View full abstract»

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  • Quantization error analysis in stereo vision

    Publication Year: 1992, Page(s):1037 - 1041 vol.2
    Cited by:  Papers (3)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (332 KB)

    The effect of quantization noise in the depth determination through stereo matching is sketched. A general treatment of the quantization noise sheds lights about how to design a stereo ranging system efficiently. A statistical error analysis is provided to help understand how the performance of a given stereo system relies on the system parameters. It is shown that a simple, but important, paramet... View full abstract»

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  • Estimation of simulation error due to trace inaccuracies

    Publication Year: 1992, Page(s):45 - 50 vol.1
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (524 KB)

    The effect of trace inaccuracies on the evaluation of cache performance using trace driven simulation is examined. It is demonstrated that very inaccurate results are obtained when using a trace from which all operating system references have been removed. The notion of trace components is defined, providing a framework for quantifying the error in simulation results when portions of the complete ... View full abstract»

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  • Array manifold interpolation for diversely polarized arrays

    Publication Year: 1992, Page(s):214 - 218 vol.1
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (344 KB)

    The interpolation problem for diversely polarized antenna arrays is examined, and interpolation techniques that provide precise direction-of-arrival (DOA) and polarization estimates are proposed. Azimuth, elevation, and frequency interpolation are also considered. The performance of the method is tested on several arrays View full abstract»

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  • Neural network based adaptive control of nonlinear plants using random search optimization algorithms

    Publication Year: 1992, Page(s):1152 - 1156 vol.2
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (324 KB)

    A method for utilizing artificial neural networks for direct adaptive control of dynamic systems with poorly known dynamics is presented. The neural network weights (controller gains) are adapted in real time using state measurements and a random search optimization algorithm. The results are demonstrated via simulation using two highly nonlinear systems View full abstract»

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  • Evolutionary optimization

    Publication Year: 1992, Page(s):409 - 414 vol.1
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (488 KB)

    Simulated evolution can be used as an effective numerical optimization procedure. The robust nature of stochastic search can be applied to general problem solving. Recent research in simulated evolution has been applied to neural network design and training, automatic control, system identification and other combinatorial problems. A brief review of these methods is offered. Some mathematical prop... View full abstract»

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  • A pipelined 45 MHz 24-bit digital signal processing ASIC

    Publication Year: 1992, Page(s):666 - 670 vol.2
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (288 KB)

    A pipelined DSP gate array that can operate at over 45 MHz and performs 24-b fixed-point arithmetic operations on arrays of complex valued inputs is described. This high performance is achieved by using a 0.8-μm three-level CMOS fabrication process, and by implementing a pipelined FFT butterfly. The partitioning of a Baugh-Wooley two's complement multiplier is discussed, and testability solutio... View full abstract»

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  • The block underdetermined covariance (BUC) fast transversal filter (FTF) algorithm for adaptive filtering

    Publication Year: 1992, Page(s):550 - 554 vol.1
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (376 KB)

    Fast algorithms in transversal filter form (FTF) developed for an adaptive filtering strategy consisting of treating consecutive blocks of L data are discussed. The resulting BUC FTF algorithm can be situated in between the normalized least-mean-square (NLMS) algorithm for L=1 and one extreme case of the block-processing FTF algorithm for L=N. A projection mecha... View full abstract»

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  • Design of an analog DFE for disk-drive applications

    Publication Year: 1992, Page(s):965 - 969 vol.2
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (356 KB)

    An architecture for a fully differential high-speed analog decision feedback equalizer is presented. Practical problems associated with an analog implementation and algorithm modifications necessary to overcome some of these problems are discussed. Circuit design and layout considerations for the equalizer as well as simulation and verification methods are described. Future improvements for higher... View full abstract»

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  • Tree-structured vector quantization with region-based classification

    Publication Year: 1992, Page(s):691 - 696 vol.2
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (368 KB)

    Unbalanced or pruned tree-structured vector quantization (PTSVQ), a variable-rate coding technique that tends to use more bits to code active regions of the image and fewer to code homogeneous ones, is developed based on a training sequence of typical images. A regression tree algorithm is used to segment the images of the training sequence using the x, y pixel location as a pred... View full abstract»

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