Pub Date : 2000-10-29DOI: 10.1109/ACSSC.2000.911282
A. Sharma, R. Moses
We investigate the use of subspace-based detectors for discriminating vehicles from trees in low frequency synthetic aperture imagery. We model tree scattering as structured isotropic interference responses and model dominant vehicle scattering as dihedral responses. We form linear subspaces of tree and target responses, and apply subspace-based detection methods developed by Scharf and Friedlander (1994). Analysis on synthetic tree and target models show the viability of this approach. Preliminary results on measured imagery provide lower performance, suggesting the need for improved data calibration and improved scattering models of trees at low frequencies.
{"title":"Matched subspace detectors for discrimination of targets from trees in SAR imagery","authors":"A. Sharma, R. Moses","doi":"10.1109/ACSSC.2000.911282","DOIUrl":"https://doi.org/10.1109/ACSSC.2000.911282","url":null,"abstract":"We investigate the use of subspace-based detectors for discriminating vehicles from trees in low frequency synthetic aperture imagery. We model tree scattering as structured isotropic interference responses and model dominant vehicle scattering as dihedral responses. We form linear subspaces of tree and target responses, and apply subspace-based detection methods developed by Scharf and Friedlander (1994). Analysis on synthetic tree and target models show the viability of this approach. Preliminary results on measured imagery provide lower performance, suggesting the need for improved data calibration and improved scattering models of trees at low frequencies.","PeriodicalId":10581,"journal":{"name":"Conference Record of the Thirty-Fourth Asilomar Conference on Signals, Systems and Computers (Cat. No.00CH37154)","volume":"16 1","pages":"1721-1726 vol.2"},"PeriodicalIF":0.0,"publicationDate":"2000-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88939774","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 : 2000-10-29DOI: 10.1109/ACSSC.2000.910974
P. Shen, C. Lindquist
Adaptive filtering allows noisy signals to be analyzed. This paper examines different types of adaptive estimation filters for EKG signals having little a priori information.
自适应滤波允许分析噪声信号。本文研究了不同类型的自适应估计滤波器对缺乏先验信息的心电信号的影响。
{"title":"Adaptive filtering of EKG signals with little a priori information","authors":"P. Shen, C. Lindquist","doi":"10.1109/ACSSC.2000.910974","DOIUrl":"https://doi.org/10.1109/ACSSC.2000.910974","url":null,"abstract":"Adaptive filtering allows noisy signals to be analyzed. This paper examines different types of adaptive estimation filters for EKG signals having little a priori information.","PeriodicalId":10581,"journal":{"name":"Conference Record of the Thirty-Fourth Asilomar Conference on Signals, Systems and Computers (Cat. No.00CH37154)","volume":"15 1","pages":"338-342 vol.1"},"PeriodicalIF":0.0,"publicationDate":"2000-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88988457","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 : 2000-10-29DOI: 10.1109/ACSSC.2000.910924
G. Mandyam
Previous work in mobile wireless communications systems has centered on the use of closed-loop transmit diversity to increase performance in fading channels. Closed-loop transmit diversity methods, which employ feedback of optimal weighting vectors so as to pre-weight transmitted symbols from multiple antennas, suffer from two problems: (1) degradation at high mobile velocities due to limited-rate feedback, and (2) increasing feedback information rate with increasing number of transmit antennas. A method of closed-loop transmit diversity which addresses both of the problems listed above is presented based on the use of unitary transformations for transmitter diversity.
{"title":"Application of unitary transforms to quasi-closed-loop transmit diversity systems","authors":"G. Mandyam","doi":"10.1109/ACSSC.2000.910924","DOIUrl":"https://doi.org/10.1109/ACSSC.2000.910924","url":null,"abstract":"Previous work in mobile wireless communications systems has centered on the use of closed-loop transmit diversity to increase performance in fading channels. Closed-loop transmit diversity methods, which employ feedback of optimal weighting vectors so as to pre-weight transmitted symbols from multiple antennas, suffer from two problems: (1) degradation at high mobile velocities due to limited-rate feedback, and (2) increasing feedback information rate with increasing number of transmit antennas. A method of closed-loop transmit diversity which addresses both of the problems listed above is presented based on the use of unitary transformations for transmitter diversity.","PeriodicalId":10581,"journal":{"name":"Conference Record of the Thirty-Fourth Asilomar Conference on Signals, Systems and Computers (Cat. No.00CH37154)","volume":"82 1","pages":"97-101 vol.1"},"PeriodicalIF":0.0,"publicationDate":"2000-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89018857","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 : 2000-10-29DOI: 10.1109/ACSSC.2000.911056
S. Mudulodu, A. Paulraj
There has been a growing interest in the use of multiple transmit and receive antennas for wireless communications, due to the enormous increase in data rate that they promise over single antenna systems. Spatial multiplexing is a scheme that aims to achieve such high data rates by transmitting an independent substream of data from each transmit antenna. However when the receive spatial signatures are poor (i.e., when the channel is not favorable), one or more transmit antennas can not be used to transmit an independent stream. In fixed modulation systems this results in some loss in data rate. We consider such fixed modulation systems and propose a scheme that uses multiple spreading codes as in CDMA MIMO (multiple input multiple output) systems to smartly combine code multiplexing with spatial multiplexing in order to mitigate this loss in data rate. We also show that, in the presence of a low bandwidth feedback path, the proposed scheme, unlike the spatial-only multiplexing scheme, allows the transmitter to adapt the data, rate smoothly based on the receive spatial signatures.
{"title":"A simple multiplexing scheme for MIMO systems using multiple spreading codes","authors":"S. Mudulodu, A. Paulraj","doi":"10.1109/ACSSC.2000.911056","DOIUrl":"https://doi.org/10.1109/ACSSC.2000.911056","url":null,"abstract":"There has been a growing interest in the use of multiple transmit and receive antennas for wireless communications, due to the enormous increase in data rate that they promise over single antenna systems. Spatial multiplexing is a scheme that aims to achieve such high data rates by transmitting an independent substream of data from each transmit antenna. However when the receive spatial signatures are poor (i.e., when the channel is not favorable), one or more transmit antennas can not be used to transmit an independent stream. In fixed modulation systems this results in some loss in data rate. We consider such fixed modulation systems and propose a scheme that uses multiple spreading codes as in CDMA MIMO (multiple input multiple output) systems to smartly combine code multiplexing with spatial multiplexing in order to mitigate this loss in data rate. We also show that, in the presence of a low bandwidth feedback path, the proposed scheme, unlike the spatial-only multiplexing scheme, allows the transmitter to adapt the data, rate smoothly based on the receive spatial signatures.","PeriodicalId":10581,"journal":{"name":"Conference Record of the Thirty-Fourth Asilomar Conference on Signals, Systems and Computers (Cat. No.00CH37154)","volume":"44 1","pages":"769-774 vol.1"},"PeriodicalIF":0.0,"publicationDate":"2000-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81332122","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 : 2000-10-29DOI: 10.1109/ACSSC.2000.910756
C. Kalluri, S.S. Rao, S. Nelatury
The problem of blind channel identification involves estimation of the channel coefficients based on the received noisy signal. The coefficients are estimated by using higher order cumulant fitting of the received signal. The optimization of the cumulant-fitting cost function is a multimodal problem, and conventional approaches using gradient algorithms often involve local optima in the absence of a good initial estimate. We use evolutionary algorithms which evolve towards better regions of search space by means of randomized processes of selection and variation, to optimize the cost function. The effectiveness of genetic algorithms as well as evolutionary programming using self-adaptive mutation as stochastic optimization techniques is studied, and the results presented for the blind channel identification problem.
{"title":"Blind channel identification using evolutionary programming","authors":"C. Kalluri, S.S. Rao, S. Nelatury","doi":"10.1109/ACSSC.2000.910756","DOIUrl":"https://doi.org/10.1109/ACSSC.2000.910756","url":null,"abstract":"The problem of blind channel identification involves estimation of the channel coefficients based on the received noisy signal. The coefficients are estimated by using higher order cumulant fitting of the received signal. The optimization of the cumulant-fitting cost function is a multimodal problem, and conventional approaches using gradient algorithms often involve local optima in the absence of a good initial estimate. We use evolutionary algorithms which evolve towards better regions of search space by means of randomized processes of selection and variation, to optimize the cost function. The effectiveness of genetic algorithms as well as evolutionary programming using self-adaptive mutation as stochastic optimization techniques is studied, and the results presented for the blind channel identification problem.","PeriodicalId":10581,"journal":{"name":"Conference Record of the Thirty-Fourth Asilomar Conference on Signals, Systems and Computers (Cat. No.00CH37154)","volume":"45 1","pages":"1212-1216 vol.2"},"PeriodicalIF":0.0,"publicationDate":"2000-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81425255","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 : 2000-10-29DOI: 10.1109/ACSSC.2000.910979
C. Ang, R. Turner, T. Courtney, R. Woods
Many practical applications of DSP require the sampling rate of a signal to be changed. This is usually achieved using linear, time-variant finite impulse response (FIR) filters such as polyphase filters. This paper describes the modelling, design and implementation of a polyphase filter using the Xilinx Virtix FPGA technology. Four solutions were explored. The first (obvious) solution involving reducing the number of multipliers by exploiting the proliferation of zeroes in the filter response. In the second and third approaches, the circuit was transformed to reduce the critical path. The fourth approach involved the development of a multiplier that multiplies a fixed number of coefficients.
{"title":"Virtex FPGA implementation of a polyphase filter for sample rate conversion","authors":"C. Ang, R. Turner, T. Courtney, R. Woods","doi":"10.1109/ACSSC.2000.910979","DOIUrl":"https://doi.org/10.1109/ACSSC.2000.910979","url":null,"abstract":"Many practical applications of DSP require the sampling rate of a signal to be changed. This is usually achieved using linear, time-variant finite impulse response (FIR) filters such as polyphase filters. This paper describes the modelling, design and implementation of a polyphase filter using the Xilinx Virtix FPGA technology. Four solutions were explored. The first (obvious) solution involving reducing the number of multipliers by exploiting the proliferation of zeroes in the filter response. In the second and third approaches, the circuit was transformed to reduce the critical path. The fourth approach involved the development of a multiplier that multiplies a fixed number of coefficients.","PeriodicalId":10581,"journal":{"name":"Conference Record of the Thirty-Fourth Asilomar Conference on Signals, Systems and Computers (Cat. No.00CH37154)","volume":"39 1","pages":"365-369 vol.1"},"PeriodicalIF":0.0,"publicationDate":"2000-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90511977","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 : 2000-10-29DOI: 10.1109/ACSSC.2000.911247
D. Garren, M. K. Osborn, A. C. Odom, J. S. Goldstein, S. Unnikrishna Pillai, J. Guerci
This paper investigates the optimization of a single transmit pulse shape and the receiver response to maximize either target detection or identity discrimination between two structurally similar ground mobile targets: the T-72 and M1 main battle tanks. This theory incorporates effects due to the uncertainty in the prior knowledge of the target aspect relative to the sensor. The improvement in the signal-to-interference-plus-noise (SINR) resulting from the optimized transmit pulse shape over that of a standard chirped waveform typically lies between 4 dB and 9 dB. Similar improvements in target identification performance are also obtained.
{"title":"Optimization of single transmit pulse shape to maximize detection and identification of ground mobile targets","authors":"D. Garren, M. K. Osborn, A. C. Odom, J. S. Goldstein, S. Unnikrishna Pillai, J. Guerci","doi":"10.1109/ACSSC.2000.911247","DOIUrl":"https://doi.org/10.1109/ACSSC.2000.911247","url":null,"abstract":"This paper investigates the optimization of a single transmit pulse shape and the receiver response to maximize either target detection or identity discrimination between two structurally similar ground mobile targets: the T-72 and M1 main battle tanks. This theory incorporates effects due to the uncertainty in the prior knowledge of the target aspect relative to the sensor. The improvement in the signal-to-interference-plus-noise (SINR) resulting from the optimized transmit pulse shape over that of a standard chirped waveform typically lies between 4 dB and 9 dB. Similar improvements in target identification performance are also obtained.","PeriodicalId":10581,"journal":{"name":"Conference Record of the Thirty-Fourth Asilomar Conference on Signals, Systems and Computers (Cat. No.00CH37154)","volume":"29 1","pages":"1535-1539 vol.2"},"PeriodicalIF":0.0,"publicationDate":"2000-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89300302","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 : 2000-10-29DOI: 10.1109/ACSSC.2000.911017
M. Koca, B. Levy
For pt.I see ibid., p.552-56 (2000). This paper presents a turbo equalization method for complex TCM signals over frequency selective, multipath fading channels based on receiver antenna array measurements. The channel observed at each array element is described as an equivalent convolutional encoder acting on the interleaved TCM symbols. The received vector signal can be viewed as produced by a serial concatenated encoder and is decoded by an iterative equalizer that employs M-ary soft output Viterbi algorithm (SOVA) as the decoding rule. Since the computational complexity of the equalizer increases with the number of ISI symbols and antennas used in the receiver, an alternative receiver is also considered where the array outputs are first combined through a beamformer and then sent to the equalizer. Both receiver structures are simulated for two dimensional TCM signals such as 8-16 PSK and 16-QAM and the results indicate an improved performance of the diversity receiver.
{"title":"Turbo space-time equalization of TCM with receiver diversity .II. Maximum-likelihood detection","authors":"M. Koca, B. Levy","doi":"10.1109/ACSSC.2000.911017","DOIUrl":"https://doi.org/10.1109/ACSSC.2000.911017","url":null,"abstract":"For pt.I see ibid., p.552-56 (2000). This paper presents a turbo equalization method for complex TCM signals over frequency selective, multipath fading channels based on receiver antenna array measurements. The channel observed at each array element is described as an equivalent convolutional encoder acting on the interleaved TCM symbols. The received vector signal can be viewed as produced by a serial concatenated encoder and is decoded by an iterative equalizer that employs M-ary soft output Viterbi algorithm (SOVA) as the decoding rule. Since the computational complexity of the equalizer increases with the number of ISI symbols and antennas used in the receiver, an alternative receiver is also considered where the array outputs are first combined through a beamformer and then sent to the equalizer. Both receiver structures are simulated for two dimensional TCM signals such as 8-16 PSK and 16-QAM and the results indicate an improved performance of the diversity receiver.","PeriodicalId":10581,"journal":{"name":"Conference Record of the Thirty-Fourth Asilomar Conference on Signals, Systems and Computers (Cat. No.00CH37154)","volume":"116 1","pages":"557-561 vol.1"},"PeriodicalIF":0.0,"publicationDate":"2000-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89412040","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 : 2000-10-29DOI: 10.1109/ACSSC.2000.910648
Badrinarayan Raghunathan, S. Acton
This paper describes an automated image segmentation technique that subdivides regions of homogeneous texture. The method utilizes a level set analysis of scaled Gabor filter responses. Scaling is achieved via an area morphological process. Each scaled, filtered image is examined to locate important connected components based on minimal total internal variance and maximal edge localization. The candidate segments are selected using a granulometry of the gradient magnitude evaluated at the level lines of the connected components. The level set analysis avoids the high computational cost associated with conventional level set approaches by sampling only the significant level sets for processing. The target application for this segmentation technique is content based image retrieval.
{"title":"Image segmentation by level set analysis","authors":"Badrinarayan Raghunathan, S. Acton","doi":"10.1109/ACSSC.2000.910648","DOIUrl":"https://doi.org/10.1109/ACSSC.2000.910648","url":null,"abstract":"This paper describes an automated image segmentation technique that subdivides regions of homogeneous texture. The method utilizes a level set analysis of scaled Gabor filter responses. Scaling is achieved via an area morphological process. Each scaled, filtered image is examined to locate important connected components based on minimal total internal variance and maximal edge localization. The candidate segments are selected using a granulometry of the gradient magnitude evaluated at the level lines of the connected components. The level set analysis avoids the high computational cost associated with conventional level set approaches by sampling only the significant level sets for processing. The target application for this segmentation technique is content based image retrieval.","PeriodicalId":10581,"journal":{"name":"Conference Record of the Thirty-Fourth Asilomar Conference on Signals, Systems and Computers (Cat. No.00CH37154)","volume":"63 1","pages":"916-920 vol.2"},"PeriodicalIF":0.0,"publicationDate":"2000-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87578394","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 : 2000-10-29DOI: 10.1109/ACSSC.2000.911054
C. Papadias
We consider the problem of receiver design of wideband multiple transmitter/multiple receiver (MTMR) antenna systems (also known as BLAST systems). While a substantial amount of work has dealt in previous years with the so-called narrow-band case, high data rate systems will require large bandwidths to support rates on the order of Mbits/s. We present some novel blind source separation (BSS) techniques which are capable of operating in such dispersive environments.
{"title":"New unsupervised processing techniques for wideband multiple transmitter/multiple receiver systems","authors":"C. Papadias","doi":"10.1109/ACSSC.2000.911054","DOIUrl":"https://doi.org/10.1109/ACSSC.2000.911054","url":null,"abstract":"We consider the problem of receiver design of wideband multiple transmitter/multiple receiver (MTMR) antenna systems (also known as BLAST systems). While a substantial amount of work has dealt in previous years with the so-called narrow-band case, high data rate systems will require large bandwidths to support rates on the order of Mbits/s. We present some novel blind source separation (BSS) techniques which are capable of operating in such dispersive environments.","PeriodicalId":10581,"journal":{"name":"Conference Record of the Thirty-Fourth Asilomar Conference on Signals, Systems and Computers (Cat. No.00CH37154)","volume":"25 1","pages":"759-763 vol.1"},"PeriodicalIF":0.0,"publicationDate":"2000-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87134502","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：