Proceedings of the Sixth International Symposium on Signal Processing and its Applications (Cat.No.01EX467)

13-16 Aug. 2001

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  • Sixth International Symposium on Signal Processing and its Applications - ISSPA 2001 [front matter]

    Publication Year: 2001, Page(s):0_1 - xiii
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    Freely Available from IEEE
  • Authors index

    Publication Year: 2001, Page(s):757 - 760
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    Freely Available from IEEE
  • Performance analysis of the time-delay phase-shifter in additive Gaussian noise: a statistical comparison with Hilbert transformer

    Publication Year: 2001, Page(s):695 - 698 vol.2
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (320 KB) | HTML iconHTML

    It is shown that, in the presence of additive Gaussian noise, the performance of the time-delay phase-shifter, which produces a signal-dependent phase shift, is comparable to the performance of a Hilbert transformer which produces a signal-independent 90-degree phase shift, especially for high signal-to-noise ratios (SNR) and the proper choice of the delay. As SNR increases, the expected value of ... View full abstract»

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  • Neural network speaker dependent isolated Malay speech recognition system: handcrafted vs genetic algorithm

    Publication Year: 2001, Page(s):731 - 734 vol.2
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (248 KB) | HTML iconHTML

    We compare two approaches in selecting neural network learning parameters and architecture. Traditionally they are found by trial and error (handcrafted) and alternatively, can be found using a genetic algorithm. Trial and error can find good solutions but the drawback is this method is time consuming and it can only try a few possible solutions while the genetic algorithm is known to be able to s... View full abstract»

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  • Parameter estimation in low-elevation target tracking

    Publication Year: 2001, Page(s):691 - 694 vol.2
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (280 KB) | HTML iconHTML

    In radar applications, when a target is in close proximity to a reflectory surface, the received echo signal reaches the radar site via two or more paths, even though there exists only one target in the environment. So, it is often relevant to estimate the directions and the relative delays of each path ray. We present two approaches to jointly estimate these parameters based on a 2D ESPRIT-like a... View full abstract»

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  • Analysis of LSF switched-predictive vector quantisers

    Publication Year: 2001, Page(s):727 - 730 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (248 KB) | HTML iconHTML

    Switched-predictive vector quantisation (SPVQ) has proven to be more efficient than conventional predictive vector quantisation (PVQ) to reduce the bit rate of LSF parameters in speech coding applications. We perform a comparison between different SPVQ schemes and we propose an extension of the SPVQ technique which outperforms previously reported PVQ and SPVQ systems. The proposed method consists ... View full abstract»

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  • Acoustic discrimination between aircraft and land vehicles using nonlinear dynamical signal models

    Publication Year: 2001, Page(s):687 - 690 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (336 KB) | HTML iconHTML

    One of the most important applications of nonlinear dynamics is the estimation of empirical dynamical models from data, in order to explain time series derived from physical processes. Such derived models can then be used for a variety of data processing applications, in particular for detection and classification problems. Previously, we presented a theory and numerical approach for the estimatio... View full abstract»

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  • A hybrid LP-harmonics model for low bit-rate speech compression with natural quality

    Publication Year: 2001, Page(s):723 - 726 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (344 KB) | HTML iconHTML

    We present a new LP-harmonic based speech codec. At the coder the speech signal is pre-processed, and an LP analysis is carried out together with pitch estimation and voicing decision. At the decoder and when the frame is voiced, the encoded parameters are used to estimate the spectrum envelope, and extract and classify the harmonies as either strong or weak depending on their relative distance fr... View full abstract»

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  • Detection of electrical series arcs using time-frequency analysis and mathematical morphology

    Publication Year: 2001, Page(s):446 - 449 vol.2
    Cited by:  Papers (1)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (352 KB) | HTML iconHTML

    A method for detecting series arcs from time-frequency analysis of the current derivative is proposed. Mathematical morphology is used to select arc features from the time-frequency representation. The proposed method has been validated on a large set of signals from various difficult electrical loads. It proves successful in separating the series arcs from the perturbations produced by the load. ... View full abstract»

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  • Quantifying perceptual image quality by difference scaling

    Publication Year: 2001, Page(s):422 - 425 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (368 KB) | HTML iconHTML

    Image compression maps an original image into a bit stream suitable for communication over or storage in a digital medium. Many image compression schemes have tried, using signal models or visual perception models, to obtain efficient image coding (high compression rates), i.e., to maintain a high image quality. We propose to measure the evolution of the quality of vector quantized color images wi... View full abstract»

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  • A DSP-based online optimal pulsewidth modulation (PWM) switching strategies for a modular structured multilevel (MSM) inverter

    Publication Year: 2001, Page(s):623 - 626 vol.2
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (320 KB) | HTML iconHTML

    Implementation of a low switching frequency modulator for optimal pulsewidth modulation (PWM) switching strategies using Texas Instruments TMS320C31 digital signal processor (DSP) as the main processor for online control of a modular structured multilevel (MSM) inverter output is presented. This is made possible through a proposed curve fitting technique to allow for online computation of the opti... View full abstract»

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  • Hybrid architectures for complex phonetic features classification: a unified approach

    Publication Year: 2001, Page(s):719 - 722 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (328 KB) | HTML iconHTML

    This paper examines how to exploit the advantages of a hybrid approach in order to overcome the drawbacks of classic automatic speech recognition (ASR) systems faced with complex phonetic features. The key idea consists of 'boosting' the capacity of a baseline ASR system to identify features as subtle as emphasis, gemination or relevant vowel lengthening. The 'booster' part is composed of a mixtur... View full abstract»

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  • Identification of DCT signs for sub-block coding

    Publication Year: 2001, Page(s):569 - 572 vol.2
    Cited by:  Patents (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (360 KB) | HTML iconHTML

    Identification of DCT signs for image coding is presented. In the JPEG DCT coding method the sign of the DCT coefficient is included in the coded signal. Usually 0.1~0.2 bit/pixel for the average bit rate is taken for coding these signs. This paper shows these DCT signs can be estimated at the receiver side almost perfectly on the basis of the smoothness cost function, so it is not needed to send ... View full abstract»

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  • Compensation of saturation effects in current transformers using neural networks

    Publication Year: 2001, Page(s):442 - 445 vol.2
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (280 KB) | HTML iconHTML

    Magnetic current transformers (CTs) are currently used in electrical devices in order to measure currents. The accuracy of CTs can severely decrease in case of saturation of the magnetic core, which can severely distort the current observed at the secondary coil of the CT. If the current in the primary coil has to be evaluated, to trip a relay for instance, saturation effects must be taken into ac... View full abstract»

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  • An alternative method for stochastic systems identification

    Publication Year: 2001, Page(s):683 - 686 vol.2
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (328 KB) | HTML iconHTML

    An alternative method is developed for stochastic systems identification in the presence of coloured noise. Central to this method is that the noise covariance vector, which determines the bias in the ordinary least-squares (LS) estimator, is estimated in the way of making use of delayed plant outputs rather than delayed plant inputs. This is very different from the other existing bias-eliminated ... View full abstract»

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  • A CMOE-CMA RAKE receiver structure for near-far frequency selective fading CDMA channels

    Publication Year: 2001, Page(s):418 - 421 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (304 KB) | HTML iconHTML

    A novel initialization scheme for a constant modulus algorithm RAKE (CMA-RAKE) receiver for frequency-selective fading asynchronous code-division multiple access (CDMA) channels is proposed. The solutions from the minimization of the constrained minimum output energy (CMOE) criterion are adopted as the initialization of the subsequent CMA receivers. The proposed receiver is proven to be near-far r... View full abstract»

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  • Online data reduction with a DSP-FPGA multiprocessor system

    Publication Year: 2001, Page(s):619 - 622 vol.2
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (432 KB) | HTML iconHTML

    For the detection of cracks and corrosion in pipelines an ultrasonic measuring system (pig) was developed. During the pipeline inspection there is no communication to the outside world, the accumulated data have to be stored on a mass storage device. The amount of data for a 250 kilometre run is in the range of about 700 TBytes at a rate of 2.8 GByte/s. There exists no robust mass storage device f... View full abstract»

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  • Broadband communications based on high altitude platform systems (HAPS) for tropical countries

    Publication Year: 2001, Page(s):517 - 520 vol.2
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (224 KB) | HTML iconHTML

    The increasing interest of broadband satellite multimedia systems has led to the consideration of higher bands operation, Ka-band (20/30 GHz). This is because of congestion of lower frequency bands such as C and Ku. Propagation impairments (rain attenuation) produced by the troposphere are a limiting factor for the effective use of the Ka-band and the use of smaller earth terminals, especially at ... View full abstract»

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  • Time-varying autoregressive modeling approach for speech segmentation

    Publication Year: 2001, Page(s):715 - 718 vol.2
    Cited by:  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (448 KB) | HTML iconHTML

    Speech is considered as a nonstationary signal since the parameters such as amplitude, frequency and phase vary with time. Traditional speech segmentation is done based on a fixed frame length. However, speech characteristics can change within the fixed length or can be similar to the adjacent frames. Thus, it would be of interest to vary the length of the segment to accommodate the changes in the... View full abstract»

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  • The importance of edges in irregular subsampling

    Publication Year: 2001, Page(s):565 - 568 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (368 KB) | HTML iconHTML

    The quality of the reconstructed image, from a very weak set of irregularly spaced pixels, depends strongly on the localization of pixels on the image grid. Two different subsampling methods show that the distribution of the pixels is closely linked to the characteristics of the image. The first method, based on the second generation of wavelets decomposes the original image in several subsets. Pi... View full abstract»

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  • A cost function for learning feedforward neural networks subject to noisy inputs

    Publication Year: 2001, Page(s):386 - 389 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (272 KB) | HTML iconHTML

    Most algorithms used for training feedforward neural networks (NN) are based on the minimization of a least squares output error cost function. The use of such a cost function provides good results when the training set is composed of noisy outputs and exactly known inputs. However, when collecting data under an identification experiment, it may not be possible to avoid noise when measuring the in... View full abstract»

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  • A mixture distribution for the wire bonding image

    Publication Year: 2001, Page(s):655 - 658 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (720 KB) | HTML iconHTML

    As a measure of quality for wire bonding, the degree of formation of intermetallics between gold ball and aluminium bond pad was estimated. A digital colour circle image of the surface of the gold ball that was attached to the bond pad was obtained. The resultant image had to be modelled by a three component mixture model proposed by Noor, Rijal, Badar and Thon, (see IEEE TENCON 2000, Kuala Lumpur... View full abstract»

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  • An expert system approach for classification of heart sounds and murmurs

    Publication Year: 2001, Page(s):739 - 740 vol.2
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (352 KB) | HTML iconHTML

    The various types of heart valvular problems can be classified from the auscultation of heart sounds and murmurs that only requires the use of the stethoscope. To discriminate the various heart sounds and murmurs, the signal parameters are estimated using the instantaneous energy and frequency estimation (IEFE) technique. The parameters are then used as inputs to an expert system classifier to cla... View full abstract»

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  • A Wigner-Ville distribution-based image dissimilarity measure

    Publication Year: 2001, Page(s):430 - 433 vol.2
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (744 KB) | HTML iconHTML

    The aim of this article is to present a new measure of image degradation based on a joint spatial/spatial-frequency representation using the Wigner-Ville distribution. The developed measure is tested on some known image degradations. The obtained results demonstrate the efficiency of the measure in predicting image quality as compared to classical distortion measures such as signal-to-noise ratio View full abstract»

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  • Fractal characterisation of non-Gaussian critical Markov random fields

    Publication Year: 2001, Page(s):663 - 666 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (248 KB) | HTML iconHTML

    We characterize a class of self-similar non-Gaussian Markov random fields (MRFs) that we call critical MRFs (CMRFs). We show that since the partition function in a Gibbs distribution of a CMRF is necessarily scale invariant, all order statistics generated from the partition function are generalized homogenous functions. This implies that the correlation function has long-range memory since it deca... View full abstract»

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