Pub Date : 1900-01-01DOI: 10.1109/ISSPA.2001.950243
Z. M. Hussain
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 the time-delay phase estimator approaches the true value of the phase and its variance substantially decreases and converges to the Cramer-Rao bound for all ranges of the effective parameters.
{"title":"Performance analysis of the time-delay phase-shifter in additive Gaussian noise: a statistical comparison with Hilbert transformer","authors":"Z. M. Hussain","doi":"10.1109/ISSPA.2001.950243","DOIUrl":"https://doi.org/10.1109/ISSPA.2001.950243","url":null,"abstract":"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 the time-delay phase estimator approaches the true value of the phase and its variance substantially decreases and converges to the Cramer-Rao bound for all ranges of the effective parameters.","PeriodicalId":236050,"journal":{"name":"Proceedings of the Sixth International Symposium on Signal Processing and its Applications (Cat.No.01EX467)","volume":"63 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":"125967798","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.2001.949783
M. Hasan, A. Hasan
Algorithms for computing signal subspace frequency or bearing estimates without eigendecomposition were described. Fast algorithms based on the power method were developed to estimate the principal and minor subspaces of the sample correlation matrices. These subspaces were then utilized to develop high-resolution methods such as MUSIC and ESPRIT for sinusoidal frequency and direction of arrival (DOA) problems. A simple squaring procedure was suggested which provides significant computational saving in comparison with exact eigendecomposition methods.
{"title":"Principal and minor subspace computation with applications","authors":"M. Hasan, A. Hasan","doi":"10.1109/ISSPA.2001.949783","DOIUrl":"https://doi.org/10.1109/ISSPA.2001.949783","url":null,"abstract":"Algorithms for computing signal subspace frequency or bearing estimates without eigendecomposition were described. Fast algorithms based on the power method were developed to estimate the principal and minor subspaces of the sample correlation matrices. These subspaces were then utilized to develop high-resolution methods such as MUSIC and ESPRIT for sinusoidal frequency and direction of arrival (DOA) problems. A simple squaring procedure was suggested which provides significant computational saving in comparison with exact eigendecomposition methods.","PeriodicalId":236050,"journal":{"name":"Proceedings of the Sixth International Symposium on Signal Processing and its Applications (Cat.No.01EX467)","volume":"49 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":"125447966","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.2001.949833
R. Pillai, S. Shah, A. Al-Khalili, D. Al-Khalili
We present a comparative study of three data path architectures for floating point multiply-accumulate fusion. Power/delay behavior of two new MAFs are compared with that of a modified IBM MAF. The functional partitioning of the new MAFs into four distinct, clock gated modules allows activity reduction. The switching activity function of the new MAFs is represented as a four state FSM. During any given operation cycle, only one of the data path modules is active, during which occasion, the logic assertion status of the circuit nodes of the other modules are maintained at their previous states. Critical path delay and latency are reduced by incorporating speculative rounding and data path simplifications. The new MAFs offer worst case power reductions in excess of 15% with FPGA realization while the corresponding figure for 0.35 micron CMOS process is better than 26%.
{"title":"Low power floating point MAFs-a comparative study","authors":"R. Pillai, S. Shah, A. Al-Khalili, D. Al-Khalili","doi":"10.1109/ISSPA.2001.949833","DOIUrl":"https://doi.org/10.1109/ISSPA.2001.949833","url":null,"abstract":"We present a comparative study of three data path architectures for floating point multiply-accumulate fusion. Power/delay behavior of two new MAFs are compared with that of a modified IBM MAF. The functional partitioning of the new MAFs into four distinct, clock gated modules allows activity reduction. The switching activity function of the new MAFs is represented as a four state FSM. During any given operation cycle, only one of the data path modules is active, during which occasion, the logic assertion status of the circuit nodes of the other modules are maintained at their previous states. Critical path delay and latency are reduced by incorporating speculative rounding and data path simplifications. The new MAFs offer worst case power reductions in excess of 15% with FPGA realization while the corresponding figure for 0.35 micron CMOS process is better than 26%.","PeriodicalId":236050,"journal":{"name":"Proceedings of the Sixth International Symposium on Signal Processing and its Applications (Cat.No.01EX467)","volume":"11 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":"128430971","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.2001.949806
Kee Ping Ho, E. Tan, Kok Cheong Wong
Behavioral modelling encompasses a number of processing requirements. These include the processing of any mental attributes, the perceived environment and the actions to be performed. These increase the load of any processor running the simulation. If there are many such behavioral modules in an animation, the playback of the scene becomes non-interactive. A simple way to improve playback speed is to store the simulation data at suitable locations. Playback of the animation is then just a matter of reading the simulation data. The speedup is often visually noticeable, although it is at the cost of storage space.
{"title":"Optimization of data access in behavioral modelling of computer animation","authors":"Kee Ping Ho, E. Tan, Kok Cheong Wong","doi":"10.1109/ISSPA.2001.949806","DOIUrl":"https://doi.org/10.1109/ISSPA.2001.949806","url":null,"abstract":"Behavioral modelling encompasses a number of processing requirements. These include the processing of any mental attributes, the perceived environment and the actions to be performed. These increase the load of any processor running the simulation. If there are many such behavioral modules in an animation, the playback of the scene becomes non-interactive. A simple way to improve playback speed is to store the simulation data at suitable locations. Playback of the animation is then just a matter of reading the simulation data. The speedup is often visually noticeable, although it is at the cost of storage space.","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":"127267445","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.2001.950209
Kofi Ghartey, D. Cochran, A. Papandreou-Suppappola
We propose to improve the performance of a generalized coherence (GC) detector using noise-suppressed estimates obtained from time varying (TV) techniques. In source detection and localization, the presence of a common but unknown signal must be detected using data from several noisy channels. If one of the channel outputs has a sufficiently high SNR, then it could be pre-processed to improve detector performance. This work uses matching pursuit decomposition (MPD), and instantaneous frequency (IF) estimation to form an estimate of the highest SNR channel output. The signal estimate is then processed by a GC detector or a generalized likelihood ratio test (GLRT) detector to detect the presence of the signal on the remaining, noisier channels. Detector performance is shown to be significantly improved via simulations.
{"title":"Multi-channel signal detection using time-varying estimation techniques","authors":"Kofi Ghartey, D. Cochran, A. Papandreou-Suppappola","doi":"10.1109/ISSPA.2001.950209","DOIUrl":"https://doi.org/10.1109/ISSPA.2001.950209","url":null,"abstract":"We propose to improve the performance of a generalized coherence (GC) detector using noise-suppressed estimates obtained from time varying (TV) techniques. In source detection and localization, the presence of a common but unknown signal must be detected using data from several noisy channels. If one of the channel outputs has a sufficiently high SNR, then it could be pre-processed to improve detector performance. This work uses matching pursuit decomposition (MPD), and instantaneous frequency (IF) estimation to form an estimate of the highest SNR channel output. The signal estimate is then processed by a GC detector or a generalized likelihood ratio test (GLRT) detector to detect the presence of the signal on the remaining, noisier channels. Detector performance is shown to be significantly improved via simulations.","PeriodicalId":236050,"journal":{"name":"Proceedings of the Sixth International Symposium on Signal Processing and its Applications (Cat.No.01EX467)","volume":"2 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":"130313661","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.2001.950238
W. Zheng
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 least-squares (BELS) methods. While achieving estimation unbiasedness, the developed method has algorithmic advantages over the prefiltering based BELS method. Moreover, its performance is comparable to the other BELS methods. Numerical results well correspond to theoretical predictions.
{"title":"An alternative method for stochastic systems identification","authors":"W. Zheng","doi":"10.1109/ISSPA.2001.950238","DOIUrl":"https://doi.org/10.1109/ISSPA.2001.950238","url":null,"abstract":"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 least-squares (BELS) methods. While achieving estimation unbiasedness, the developed method has algorithmic advantages over the prefiltering based BELS method. Moreover, its performance is comparable to the other BELS methods. Numerical results well correspond to theoretical predictions.","PeriodicalId":236050,"journal":{"name":"Proceedings of the Sixth International Symposium on Signal Processing and its Applications (Cat.No.01EX467)","volume":"11 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":"134012353","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.2001.950227
Longin Jan Latecki, D. DeMenthon, A. Rosenfeld
We apply the polygon simplification method to automatically obtain the most relevant key frames. First a video sequence is mapped to a polyline in R/sup 37/. By simplifying this polyline, we obtain a summarization (i.e., a small set of the most relevant frames) that is representative of the whole video sequence. The degree of the simplification is either determined automatically or selected by the user.
{"title":"Extraction of key frames from videos by polygon simplification","authors":"Longin Jan Latecki, D. DeMenthon, A. Rosenfeld","doi":"10.1109/ISSPA.2001.950227","DOIUrl":"https://doi.org/10.1109/ISSPA.2001.950227","url":null,"abstract":"We apply the polygon simplification method to automatically obtain the most relevant key frames. First a video sequence is mapped to a polyline in R/sup 37/. By simplifying this polyline, we obtain a summarization (i.e., a small set of the most relevant frames) that is representative of the whole video sequence. The degree of the simplification is either determined automatically or selected by the user.","PeriodicalId":236050,"journal":{"name":"Proceedings of the Sixth International Symposium on Signal Processing and its Applications (Cat.No.01EX467)","volume":"37 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":"131180360","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.2001.949780
J. Manton
The classical steepest descent and Newton algorithms can be used to minimise a cost function f(X). This paper shows how they can be modified to take into account the constraint that the columns of the complex-valued matrix X are mutually orthogonal and have unit norm. The algorithms are derived by converting the constrained optimisation problem into an unconstrained one on the Stiefel manifold. This significantly reduces the dimension of the optimisation problem and often results in faster convergence.
{"title":"Modified steepest descent and Newton algorithms for orthogonally constrained optimisation. Part I. The complex Stiefel manifold","authors":"J. Manton","doi":"10.1109/ISSPA.2001.949780","DOIUrl":"https://doi.org/10.1109/ISSPA.2001.949780","url":null,"abstract":"The classical steepest descent and Newton algorithms can be used to minimise a cost function f(X). This paper shows how they can be modified to take into account the constraint that the columns of the complex-valued matrix X are mutually orthogonal and have unit norm. The algorithms are derived by converting the constrained optimisation problem into an unconstrained one on the Stiefel manifold. This significantly reduces the dimension of the optimisation problem and often results in faster convergence.","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":"129530275","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.2001.950242
M. Djeddou, A. Belouchrani
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 algorithm Van der Veen et al., (1998) in wireless communications. Numerical simulations are provided to access the performance of the proposed approaches, which are compared to the Cramer-Rao bound and the MUSIC algorithm combined with spatial smoothing.
在雷达应用中，当目标靠近反射表面时，即使环境中只有一个目标，接收到的回波信号也会通过两条或多条路径到达雷达站点。因此，估计每条路径射线的方向和相对延迟往往是有意义的。我们提出了两种方法来联合估计这些参数基于二维esprit类算法Van der Veen等人，(1998)在无线通信。通过数值仿真验证了所提方法的性能，并将其与Cramer-Rao界和结合空间平滑的MUSIC算法进行了比较。
{"title":"Parameter estimation in low-elevation target tracking","authors":"M. Djeddou, A. Belouchrani","doi":"10.1109/ISSPA.2001.950242","DOIUrl":"https://doi.org/10.1109/ISSPA.2001.950242","url":null,"abstract":"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 algorithm Van der Veen et al., (1998) in wireless communications. Numerical simulations are provided to access the performance of the proposed approaches, which are compared to the Cramer-Rao bound and the MUSIC algorithm combined with spatial smoothing.","PeriodicalId":236050,"journal":{"name":"Proceedings of the Sixth International Symposium on Signal Processing and its Applications (Cat.No.01EX467)","volume":"15 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":"131023161","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.2001.950248
S. M. Tahir, A. Sha'ameri, S. Salleh
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 speech characteristics. The developed segmentation algorithm is based on a time-varying autoregressive model and the segmentation rules are developed based on the instantaneous energy and frequency estimate.
{"title":"Time-varying autoregressive modeling approach for speech segmentation","authors":"S. M. Tahir, A. Sha'ameri, S. Salleh","doi":"10.1109/ISSPA.2001.950248","DOIUrl":"https://doi.org/10.1109/ISSPA.2001.950248","url":null,"abstract":"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 speech characteristics. The developed segmentation algorithm is based on a time-varying autoregressive model and the segmentation rules are developed based on the instantaneous energy and frequency estimate.","PeriodicalId":236050,"journal":{"name":"Proceedings of the Sixth International Symposium on Signal Processing and its Applications (Cat.No.01EX467)","volume":"33 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":"132313822","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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