Pub Date : 1900-01-01DOI: 10.1109/ISSPA.2001.950169
P. Yuvapoositanon, J. Chambers
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 resistant at different levels of near-far problems. Simulations confirm the superiority of the receiver over the existing RAKE receivers in terms of signal-to-interference plus noise (SINR) ratio over a wide range of near-far situations.
{"title":"A CMOE-CMA RAKE receiver structure for near-far frequency selective fading CDMA channels","authors":"P. Yuvapoositanon, J. Chambers","doi":"10.1109/ISSPA.2001.950169","DOIUrl":"https://doi.org/10.1109/ISSPA.2001.950169","url":null,"abstract":"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 resistant at different levels of near-far problems. Simulations confirm the superiority of the receiver over the existing RAKE receivers in terms of signal-to-interference plus noise (SINR) ratio over a wide range of near-far situations.","PeriodicalId":236050,"journal":{"name":"Proceedings of the Sixth International Symposium on Signal Processing and its Applications (Cat.No.01EX467)","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115379454","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.1109/ISSPA.2001.950200
A. Bouzerdoum
We introduce a new stochastic competitive learning algorithm (SCoLA) and apply it to vector quantization for image compression. In competitive learning, the training process involves presenting, simultaneously, an input vector to each of the competing neurons, which then compare the input vector to their own weight vectors and one of them is declared the winner based on some deterministic distortion measure. Here a stochastic criterion is used for selecting the winning neuron, whose weights are then updated to become more like the input vector. The performance of the new algorithm is compared to that of frequency-sensitive competitive learning (FSCL); it was found that SCoLA achieves higher peak signal-to-noise ratios (PSNR) than FSCL.
{"title":"Image compression using a stochastic competitive learning algorithm (SCoLA)","authors":"A. Bouzerdoum","doi":"10.1109/ISSPA.2001.950200","DOIUrl":"https://doi.org/10.1109/ISSPA.2001.950200","url":null,"abstract":"We introduce a new stochastic competitive learning algorithm (SCoLA) and apply it to vector quantization for image compression. In competitive learning, the training process involves presenting, simultaneously, an input vector to each of the competing neurons, which then compare the input vector to their own weight vectors and one of them is declared the winner based on some deterministic distortion measure. Here a stochastic criterion is used for selecting the winning neuron, whose weights are then updated to become more like the input vector. The performance of the new algorithm is compared to that of frequency-sensitive competitive learning (FSCL); it was found that SCoLA achieves higher peak signal-to-noise ratios (PSNR) than FSCL.","PeriodicalId":236050,"journal":{"name":"Proceedings of the Sixth International Symposium on Signal Processing and its Applications (Cat.No.01EX467)","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114894080","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.1109/ISSPA.2001.949766
T. Deng
This paper presents a closed-form solution for obtaining the optimal coefficients of variable FIR filters with continuously adjustable fractional-delay (FD) response. The design is formulated as a weighted-least-squares (WLS) approximation problem without discretizing the frequency and fractional-delay parameters. Compared with the existing WLS method, the discretization-free one can yield a closed-form optimal solution with considerably reduced computational complexity.
{"title":"Optimal design of variable fractional-delay digital filters","authors":"T. Deng","doi":"10.1109/ISSPA.2001.949766","DOIUrl":"https://doi.org/10.1109/ISSPA.2001.949766","url":null,"abstract":"This paper presents a closed-form solution for obtaining the optimal coefficients of variable FIR filters with continuously adjustable fractional-delay (FD) response. The design is formulated as a weighted-least-squares (WLS) approximation problem without discretizing the frequency and fractional-delay parameters. Compared with the existing WLS method, the discretization-free one can yield a closed-form optimal solution with considerably reduced computational complexity.","PeriodicalId":236050,"journal":{"name":"Proceedings of the Sixth International Symposium on Signal Processing and its Applications (Cat.No.01EX467)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125891358","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.1109/ISSPA.2001.950175
B. Leprettre, P. Bastard
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 account. A method using neural networks (NNs) is proposed. First, a large set of current signals encountered in low voltage installations has been built. Saturation has been added with a previously validated CT model. Then, a NN has been trained to invert the saturation effects and to reconstruct the primary current from the distorted one.
{"title":"Compensation of saturation effects in current transformers using neural networks","authors":"B. Leprettre, P. Bastard","doi":"10.1109/ISSPA.2001.950175","DOIUrl":"https://doi.org/10.1109/ISSPA.2001.950175","url":null,"abstract":"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 account. A method using neural networks (NNs) is proposed. First, a large set of current signals encountered in low voltage installations has been built. Saturation has been added with a previously validated CT model. Then, a NN has been trained to invert the saturation effects and to reconstruct the primary current from the distorted one.","PeriodicalId":236050,"journal":{"name":"Proceedings of the Sixth International Symposium on Signal Processing and its Applications (Cat.No.01EX467)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128655162","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.1109/ISSPA.2001.950204
A. Nguyen, V. Chandran, S. Sridharan, R. Prandolini
This paper presents an importance coding technique to improve the interpretability versus bit-rate performance for an image compression system. The term interpretability is a subjective image quality measure of the content recognition performance by trained image analysts. A quadtree dynamics importance map is used to aid the prioritisation of the image encoded bit-stream according to its importance for interpretability. The importance map is generated using several bottom-up, context-free features for the identification of regions-of-interest in surveillance imagery that correlate well with visual attention processes in humans. Traditional PSNR progressive coders rely on descending wavelet coefficient magnitudes to prioritise the encoded bit-stream. The importance coder discussed in the paper is designed such that the JPEG2000 standard can implement the importance prioritisation schema (without the need to send the importance map information). Subjective evaluations indicate that the proposed schema is better than traditional PSNR progressive coders for the purpose of very low bitrate content recognition.
{"title":"Importance coding of surveillance imagery for interpretability using quadtree dynamic importance maps","authors":"A. Nguyen, V. Chandran, S. Sridharan, R. Prandolini","doi":"10.1109/ISSPA.2001.950204","DOIUrl":"https://doi.org/10.1109/ISSPA.2001.950204","url":null,"abstract":"This paper presents an importance coding technique to improve the interpretability versus bit-rate performance for an image compression system. The term interpretability is a subjective image quality measure of the content recognition performance by trained image analysts. A quadtree dynamics importance map is used to aid the prioritisation of the image encoded bit-stream according to its importance for interpretability. The importance map is generated using several bottom-up, context-free features for the identification of regions-of-interest in surveillance imagery that correlate well with visual attention processes in humans. Traditional PSNR progressive coders rely on descending wavelet coefficient magnitudes to prioritise the encoded bit-stream. The importance coder discussed in the paper is designed such that the JPEG2000 standard can implement the importance prioritisation schema (without the need to send the importance map information). Subjective evaluations indicate that the proposed schema is better than traditional PSNR progressive coders for the purpose of very low bitrate content recognition.","PeriodicalId":236050,"journal":{"name":"Proceedings of the Sixth International Symposium on Signal Processing and its Applications (Cat.No.01EX467)","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127451192","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.1109/ISSPA.2001.949791
M. Hasan
Fast methods for approximating the dominant and subdominant subspaces have been developed. These methods offer a computational benefit in that subspaces are computed without the costly eigendecomposition or singular value decomposition. More generally we provided a way of splitting an L-dimensional space into several complementary invariant subspaces of the sample covariance matrix, without actually computing any eigenvalues. Frequency estimators such as MUSIC-, minimum-norm-, and ESPRIT-type are then derived using these approximated subspaces. The computation of obtaining these approximate subspaces and estimators are shown to be less than the standard techniques. Through several examples it is demonstrated that these methods have a performance comparable to that of MUSIC yet will require fewer computation to obtain the signal subspace projection.
{"title":"Fast rational approximation algorithms of signal and noise subspaces","authors":"M. Hasan","doi":"10.1109/ISSPA.2001.949791","DOIUrl":"https://doi.org/10.1109/ISSPA.2001.949791","url":null,"abstract":"Fast methods for approximating the dominant and subdominant subspaces have been developed. These methods offer a computational benefit in that subspaces are computed without the costly eigendecomposition or singular value decomposition. More generally we provided a way of splitting an L-dimensional space into several complementary invariant subspaces of the sample covariance matrix, without actually computing any eigenvalues. Frequency estimators such as MUSIC-, minimum-norm-, and ESPRIT-type are then derived using these approximated subspaces. The computation of obtaining these approximate subspaces and estimators are shown to be less than the standard techniques. Through several examples it is demonstrated that these methods have a performance comparable to that of MUSIC yet will require fewer computation to obtain the signal subspace projection.","PeriodicalId":236050,"journal":{"name":"Proceedings of the Sixth International Symposium on Signal Processing and its Applications (Cat.No.01EX467)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130711939","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.1109/ISSPA.2001.949826
S. Carstens-Behrens, J. Böhme
This work presents the application of three different time-frequency methods to pressure and structure-borne sound signals to improve combustion diagnosis of internal combustion engines. Increasing engine efficiency and reduction of pollutants imply enhanced knowledge of the combustion process. The methods presented deepen the understanding of the measured signal and stimulate improved algorithms for knock detection.
{"title":"Applying time-frequency methods to pressure and structure-borne sound for combustion diagnosis","authors":"S. Carstens-Behrens, J. Böhme","doi":"10.1109/ISSPA.2001.949826","DOIUrl":"https://doi.org/10.1109/ISSPA.2001.949826","url":null,"abstract":"This work presents the application of three different time-frequency methods to pressure and structure-borne sound signals to improve combustion diagnosis of internal combustion engines. Increasing engine efficiency and reduction of pollutants imply enhanced knowledge of the combustion process. The methods presented deepen the understanding of the measured signal and stimulate improved algorithms for knock detection.","PeriodicalId":236050,"journal":{"name":"Proceedings of the Sixth International Symposium on Signal Processing and its Applications (Cat.No.01EX467)","volume":"611 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132950407","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.1109/ISSPA.2001.950247
Daryl Ning, Mohamed Deriche
In this paper, we present results for a combined wavelet warped linear prediction (WLP) audio coder. In contrast to conventional LP, WLP allows for the control of frequency resolution to closely match the response of the human auditory system. The coder first uses WLP analysis on each frame of audio, and then applies a discrete wavelet transform (DWT) to the residual signal (prediction error). A psychoacoustic model is used in parallel to obtain a global masking threshold used in bit allocation. Bits are dynamically allocated to the DWT coefficients in an attempt to minimise the perceptually significant quantisation error. For monophonic signals sampled at 44.1 kHz, the coder achieves near transparent quality for a variety of speech and music signals at an average bit-rate of 64 kb/s. The power of the proposed coder resides in its easy scalability to lower bit rates.
{"title":"Wideband audio compression using a combined wavelet and WLPC representation","authors":"Daryl Ning, Mohamed Deriche","doi":"10.1109/ISSPA.2001.950247","DOIUrl":"https://doi.org/10.1109/ISSPA.2001.950247","url":null,"abstract":"In this paper, we present results for a combined wavelet warped linear prediction (WLP) audio coder. In contrast to conventional LP, WLP allows for the control of frequency resolution to closely match the response of the human auditory system. The coder first uses WLP analysis on each frame of audio, and then applies a discrete wavelet transform (DWT) to the residual signal (prediction error). A psychoacoustic model is used in parallel to obtain a global masking threshold used in bit allocation. Bits are dynamically allocated to the DWT coefficients in an attempt to minimise the perceptually significant quantisation error. For monophonic signals sampled at 44.1 kHz, the coder achieves near transparent quality for a variety of speech and music signals at an average bit-rate of 64 kb/s. The power of the proposed coder resides in its easy scalability to lower bit rates.","PeriodicalId":236050,"journal":{"name":"Proceedings of the Sixth International Symposium on Signal Processing and its Applications (Cat.No.01EX467)","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130219887","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.1109/ISSPA.2001.950219
M. Bhattacharya, J. Astola, T. Saramäki
One of the method of reducing coefficient sensitivity is that of coefficient translation. The structure is altered in such a way that the sensitivity with respect to the modified coefficients is reduced to a great extent compared to that with respect to the original coefficients. In low sensitivity structures the modified coefficients can be realized with multipliers of shorter wordlength i.e., in fewer number bits. When these are implemented in minimum numbers of signed powers of two (MNSPT) form, we have a multiplierless implementation These implementations are not associated with increase in the order of the filter that involves more number of shift registers, data paths, control circuits, etc., and hence, an increase in complexity i.e. indirect overheads.
{"title":"Multiplierless implementation of recursive digital filters using a class of low sensitivity structures","authors":"M. Bhattacharya, J. Astola, T. Saramäki","doi":"10.1109/ISSPA.2001.950219","DOIUrl":"https://doi.org/10.1109/ISSPA.2001.950219","url":null,"abstract":"One of the method of reducing coefficient sensitivity is that of coefficient translation. The structure is altered in such a way that the sensitivity with respect to the modified coefficients is reduced to a great extent compared to that with respect to the original coefficients. In low sensitivity structures the modified coefficients can be realized with multipliers of shorter wordlength i.e., in fewer number bits. When these are implemented in minimum numbers of signed powers of two (MNSPT) form, we have a multiplierless implementation These implementations are not associated with increase in the order of the filter that involves more number of shift registers, data paths, control circuits, etc., and hence, an increase in complexity i.e. indirect overheads.","PeriodicalId":236050,"journal":{"name":"Proceedings of the Sixth International Symposium on Signal Processing and its Applications (Cat.No.01EX467)","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127991716","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.1109/ISSPA.2001.950192
G. Azemi, B. Senadji, B. Boashash
Estimating the velocity of the mobile units is of great importance in hierarchical cellular systems since the satisfactory handover of mobiles to macro or micro-cells depends on its present velocity. In this contribution, the first moment of the instantaneous frequency (IF) of the received signal, is proposed as a new velocity estimator. The performance of this estimator in the presence of Rayleigh fading, log-normal shadowing, and additive white Gaussian noise is compared with the conventional zero crossing rate (ZCR) estimator. Simulations show that the performance of the proposed estimator is superior to that of the ZCR velocity estimator, in the presence of additive noise. Also it has been shown that the IF velocity estimator is robust in the presence of shadowing.
{"title":"Velocity estimation in cellular systems based on the time-frequency characteristics of the received signal","authors":"G. Azemi, B. Senadji, B. Boashash","doi":"10.1109/ISSPA.2001.950192","DOIUrl":"https://doi.org/10.1109/ISSPA.2001.950192","url":null,"abstract":"Estimating the velocity of the mobile units is of great importance in hierarchical cellular systems since the satisfactory handover of mobiles to macro or micro-cells depends on its present velocity. In this contribution, the first moment of the instantaneous frequency (IF) of the received signal, is proposed as a new velocity estimator. The performance of this estimator in the presence of Rayleigh fading, log-normal shadowing, and additive white Gaussian noise is compared with the conventional zero crossing rate (ZCR) estimator. Simulations show that the performance of the proposed estimator is superior to that of the ZCR velocity estimator, in the presence of additive noise. Also it has been shown that the IF velocity estimator is robust in the presence of shadowing.","PeriodicalId":236050,"journal":{"name":"Proceedings of the Sixth International Symposium on Signal Processing and its Applications (Cat.No.01EX467)","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126675776","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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