Pub Date : 2007-11-01DOI: 10.1109/ICSPC.2007.4728329
S. Tripathi, K. Saha, E. Piccinelli
This paper describes a new transcoding algorithm, able to transcode any coded (e.g. MPEG-2) bit-stream into an H.264 sequence with arbitrary spatial resolution change. The visual quality at a given input and output bit-rate is close or equal to full decoding followed by a full encoding (0.5 dB-to-2 dB less in PSNR than that of re-encoding the stream at the target resolution) while, from the complexity point of view, the proposed transcoding approach is at least ten times faster than re-encoding. The experimental results show that this H.264 transcoder always gives about 20 to 60% better compression than that of the size of the original MPEG2 sequence scaled by the target resolution ratio at equal subjective quality. Using constant quantization parameters both in the transcoding and re-encoding, transcoding gives 20 to 40% lesser compression than re-encoding.
{"title":"Pre-Coded Video Transcoding into H.264 with Arbitrary Resolution Change","authors":"S. Tripathi, K. Saha, E. Piccinelli","doi":"10.1109/ICSPC.2007.4728329","DOIUrl":"https://doi.org/10.1109/ICSPC.2007.4728329","url":null,"abstract":"This paper describes a new transcoding algorithm, able to transcode any coded (e.g. MPEG-2) bit-stream into an H.264 sequence with arbitrary spatial resolution change. The visual quality at a given input and output bit-rate is close or equal to full decoding followed by a full encoding (0.5 dB-to-2 dB less in PSNR than that of re-encoding the stream at the target resolution) while, from the complexity point of view, the proposed transcoding approach is at least ten times faster than re-encoding. The experimental results show that this H.264 transcoder always gives about 20 to 60% better compression than that of the size of the original MPEG2 sequence scaled by the target resolution ratio at equal subjective quality. Using constant quantization parameters both in the transcoding and re-encoding, transcoding gives 20 to 40% lesser compression than re-encoding.","PeriodicalId":425397,"journal":{"name":"2007 IEEE International Conference on Signal Processing and Communications","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127398805","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 : 2007-11-01DOI: 10.1109/ICSPC.2007.4728440
E. Sánchez-Soto, K. Daoudi, A. Potamianos
We propose an efficient algorithm for unsupervised stream weight estimation in a segmentation task. Our method uses only the information carried by the test signal and the trained models. The work is based on results presented previously for the classification problem where it is indicated that the optimal stream weights are inversely proportional to the single stream misclassification error. We approximate this error relation by the intra- and inter-class distance ratio over the measured class distributions. This approach is then generalized to the segmentation problem by computing the distances among all the concerned classes. The proposed unsupervised estimation algorithm is evaluated on a an audio-visual speech recognition task. The obtained performances are comparable to the supervised minimum error training approach, up to a certain SNR level.
{"title":"Unsupervised Stream Weight Computation in a Segmentaion Task: Application to Audio-Visual Speech Recognition","authors":"E. Sánchez-Soto, K. Daoudi, A. Potamianos","doi":"10.1109/ICSPC.2007.4728440","DOIUrl":"https://doi.org/10.1109/ICSPC.2007.4728440","url":null,"abstract":"We propose an efficient algorithm for unsupervised stream weight estimation in a segmentation task. Our method uses only the information carried by the test signal and the trained models. The work is based on results presented previously for the classification problem where it is indicated that the optimal stream weights are inversely proportional to the single stream misclassification error. We approximate this error relation by the intra- and inter-class distance ratio over the measured class distributions. This approach is then generalized to the segmentation problem by computing the distances among all the concerned classes. The proposed unsupervised estimation algorithm is evaluated on a an audio-visual speech recognition task. The obtained performances are comparable to the supervised minimum error training approach, up to a certain SNR level.","PeriodicalId":425397,"journal":{"name":"2007 IEEE International Conference on Signal Processing and Communications","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129985685","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 : 2007-11-01DOI: 10.1109/ICSPC.2007.4728625
S. Changuel, R. Le Bidan, R. Pyndiah
This paper investigates iterative decoding of product codes over the binary erasure channel. A simplified row-column iterative decoding algorithm combining bit guessing with bounded-distance erasure decoding is introduced. This algorithm shares many similarities with the original Chase-Pyndiah turbo decoding algorithm and offers a wide range of trade-offs between performance and complexity. The performance of the proposed iterative decoding algorithm has been evaluated by Monte-Carlo simulation for several selected high-rate product codes. Both binary Bose-Chaudhuri-Hocquenghem and non-binary Reed-Solomon component codes have been considered. The results show that product codes provide near-capacity performance without exhibiting error floors in the simulated word-erasure-rate region.
{"title":"Iterative Decoding of Block Turbo Codes over the Binary Erasure Channel","authors":"S. Changuel, R. Le Bidan, R. Pyndiah","doi":"10.1109/ICSPC.2007.4728625","DOIUrl":"https://doi.org/10.1109/ICSPC.2007.4728625","url":null,"abstract":"This paper investigates iterative decoding of product codes over the binary erasure channel. A simplified row-column iterative decoding algorithm combining bit guessing with bounded-distance erasure decoding is introduced. This algorithm shares many similarities with the original Chase-Pyndiah turbo decoding algorithm and offers a wide range of trade-offs between performance and complexity. The performance of the proposed iterative decoding algorithm has been evaluated by Monte-Carlo simulation for several selected high-rate product codes. Both binary Bose-Chaudhuri-Hocquenghem and non-binary Reed-Solomon component codes have been considered. The results show that product codes provide near-capacity performance without exhibiting error floors in the simulated word-erasure-rate region.","PeriodicalId":425397,"journal":{"name":"2007 IEEE International Conference on Signal Processing and Communications","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132384668","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 : 2007-11-01DOI: 10.1109/ICSPC.2007.4728343
R. Abd‐Alhameed, P. Excell
A moment-method formulation was developed using two geometrically-orthogonal basis functions to represent the total non-uniform surface current distribution over a wire radiating element. Extended basis functions were used to reliably treat the discontinuity of the current at the free ends. A surface kernel was used over all of the antenna structure. It was found that the axially-directed component of the current distribution around the surface of the wire was highly non-uniform and that there was also a significant circumferential current flow due to capacitance between parallel wires, both of these being effects that are overlooked by standard filamentary current representations using an extended kernel. The impedance characteristic showed good agreement with the predictions of a standard filamentary-current code, in the case of applied uniform excitation along the local axis of the wire. However, the power loss computations produce significantly different results.
{"title":"Accurate Power Loss Computation of Closely-Spaced Radiating Wire Elements for Mobile Phone MIMO Application","authors":"R. Abd‐Alhameed, P. Excell","doi":"10.1109/ICSPC.2007.4728343","DOIUrl":"https://doi.org/10.1109/ICSPC.2007.4728343","url":null,"abstract":"A moment-method formulation was developed using two geometrically-orthogonal basis functions to represent the total non-uniform surface current distribution over a wire radiating element. Extended basis functions were used to reliably treat the discontinuity of the current at the free ends. A surface kernel was used over all of the antenna structure. It was found that the axially-directed component of the current distribution around the surface of the wire was highly non-uniform and that there was also a significant circumferential current flow due to capacitance between parallel wires, both of these being effects that are overlooked by standard filamentary current representations using an extended kernel. The impedance characteristic showed good agreement with the predictions of a standard filamentary-current code, in the case of applied uniform excitation along the local axis of the wire. However, the power loss computations produce significantly different results.","PeriodicalId":425397,"journal":{"name":"2007 IEEE International Conference on Signal Processing and Communications","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131681843","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 : 2007-11-01DOI: 10.1109/ICSPC.2007.4728569
H. Karkhaneh, T. Sadeghpour, A. Ghorbani, R. Abd‐Alhameed
This paper is concerned with a new time-domain modeling topology for signals which is applied to wideband power amplifiers. The memory effect will be shown using two-tone intermodulation distortion (IMD) measurement with different tone frequency spacing and power levels. The model is developed by using a memoryless nonlinearity followed by a dynamic LTI system (Hammerstein model) to consider the memory effects associated with wideband signals. For this purpose an Nth-order FIR filter is used. It is shown that the accuracy of wideband signal simulations can be improved by optimizing the model parameters based on time-domain measurements of wideband signals.
{"title":"Modeling of Nonlinear Power Amplifier with Memory Effect for Wideband Application","authors":"H. Karkhaneh, T. Sadeghpour, A. Ghorbani, R. Abd‐Alhameed","doi":"10.1109/ICSPC.2007.4728569","DOIUrl":"https://doi.org/10.1109/ICSPC.2007.4728569","url":null,"abstract":"This paper is concerned with a new time-domain modeling topology for signals which is applied to wideband power amplifiers. The memory effect will be shown using two-tone intermodulation distortion (IMD) measurement with different tone frequency spacing and power levels. The model is developed by using a memoryless nonlinearity followed by a dynamic LTI system (Hammerstein model) to consider the memory effects associated with wideband signals. For this purpose an Nth-order FIR filter is used. It is shown that the accuracy of wideband signal simulations can be improved by optimizing the model parameters based on time-domain measurements of wideband signals.","PeriodicalId":425397,"journal":{"name":"2007 IEEE International Conference on Signal Processing and Communications","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126852914","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 : 2007-11-01DOI: 10.1109/ICSPC.2007.4728330
M. Elmusrati, N. Tarhuni, R. Jantti
When the channel measurement update rate is very slow compared to the channel fluctuations, the performance of conventional power control algorithms is greatly reduced. In this paper we introduce novel method to update the transmit power in such extreme situations. We propose to use random power allocation with certain distribution function and then using the channel measurements to update the statistics of this random power rather the power value itself. The truncated inverted exponential distribution is one candidate for the power distribution which is used in this paper. This distribution has one parameter which can be easily updated according to the channel quality. The signal-to-interference and noise ratio (SINR) is used as an indicator for the channel quality. The probability of outage when using the proposed power allocation is also given in mathematical form. Simulations show that, one may improve the average SINR when using the proposed algorithm compared to the conventional distributed power control algorithm.
{"title":"Random Power Control for Uncorrelated Rayleigh Fading Channels","authors":"M. Elmusrati, N. Tarhuni, R. Jantti","doi":"10.1109/ICSPC.2007.4728330","DOIUrl":"https://doi.org/10.1109/ICSPC.2007.4728330","url":null,"abstract":"When the channel measurement update rate is very slow compared to the channel fluctuations, the performance of conventional power control algorithms is greatly reduced. In this paper we introduce novel method to update the transmit power in such extreme situations. We propose to use random power allocation with certain distribution function and then using the channel measurements to update the statistics of this random power rather the power value itself. The truncated inverted exponential distribution is one candidate for the power distribution which is used in this paper. This distribution has one parameter which can be easily updated according to the channel quality. The signal-to-interference and noise ratio (SINR) is used as an indicator for the channel quality. The probability of outage when using the proposed power allocation is also given in mathematical form. Simulations show that, one may improve the average SINR when using the proposed algorithm compared to the conventional distributed power control algorithm.","PeriodicalId":425397,"journal":{"name":"2007 IEEE International Conference on Signal Processing and Communications","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123349829","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 : 2007-11-01DOI: 10.1109/ICSPC.2007.4728368
H. Farsi
Pre-assumption for low bit rate speech coding is that pitch evolves smoothly and pitch cycles are highly correlated for voiced speech. Due to non stationary characteristics of speech signal, this assumption is sometimes inaccurate and therefore the performance of speech coder is affected. In this paper, low correlated pitch cycles are specified and then modified using target correlation concept which maintaining perceptual speech quality identical to original speech. Since the modification is performed independently from speech coder, this can be applied as a pre-processing in low bit rate speech coding to provide more regular speech.
{"title":"Pitch Cycles Evolutions Smoothing for More Regular Speech using Target Correlation Approach","authors":"H. Farsi","doi":"10.1109/ICSPC.2007.4728368","DOIUrl":"https://doi.org/10.1109/ICSPC.2007.4728368","url":null,"abstract":"Pre-assumption for low bit rate speech coding is that pitch evolves smoothly and pitch cycles are highly correlated for voiced speech. Due to non stationary characteristics of speech signal, this assumption is sometimes inaccurate and therefore the performance of speech coder is affected. In this paper, low correlated pitch cycles are specified and then modified using target correlation concept which maintaining perceptual speech quality identical to original speech. Since the modification is performed independently from speech coder, this can be applied as a pre-processing in low bit rate speech coding to provide more regular speech.","PeriodicalId":425397,"journal":{"name":"2007 IEEE International Conference on Signal Processing and Communications","volume":"339 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126357174","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 : 2007-11-01DOI: 10.1109/ICSPC.2007.4728554
K. Bartusek, Z. Dokoupil
The paper describes a newly proposed magnetic resonance (MR) method and the processing of signals being measured, with the aim of establishing the diffusion coefficients in heterogeneous materials with short relaxation times T2. The measuring method and the digital signal processing enable eliminating the effect of static magnetic field on the accuracy of measuring. The method proposed can be used to measure diffusion-weighted images of liquids found in porous materials, and in the development of new MR tomography measuring methods in the Institute of Scientific Instruments of the Academy of Sciences of the Czech Republic, v.v.i.
{"title":"Interesting Method of MR Diffusion Measurement","authors":"K. Bartusek, Z. Dokoupil","doi":"10.1109/ICSPC.2007.4728554","DOIUrl":"https://doi.org/10.1109/ICSPC.2007.4728554","url":null,"abstract":"The paper describes a newly proposed magnetic resonance (MR) method and the processing of signals being measured, with the aim of establishing the diffusion coefficients in heterogeneous materials with short relaxation times T2. The measuring method and the digital signal processing enable eliminating the effect of static magnetic field on the accuracy of measuring. The method proposed can be used to measure diffusion-weighted images of liquids found in porous materials, and in the development of new MR tomography measuring methods in the Institute of Scientific Instruments of the Academy of Sciences of the Czech Republic, v.v.i.","PeriodicalId":425397,"journal":{"name":"2007 IEEE International Conference on Signal Processing and Communications","volume":"75 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121612447","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 : 2007-11-01DOI: 10.1109/ICSPC.2007.4728401
I. Cherif, S. Abid, F. Fnaiech
The blind identification of a special class of nonlinear system is pursued in this paper. In particular a genetic algorithm is developed for blind identification of quadratic Volterra model excited by an unobservable input signal which can either be a stationary Gaussian process or an i.i.d process. This approach enables a nonlinear relationship between model kernels and output cumulants up to third order. Simulation results are presented to show good performance of this approach.
{"title":"Blind Nonlinear System Identification Under Gaussian And / Or I.I.D. Excitation Using Genetic Algorithms","authors":"I. Cherif, S. Abid, F. Fnaiech","doi":"10.1109/ICSPC.2007.4728401","DOIUrl":"https://doi.org/10.1109/ICSPC.2007.4728401","url":null,"abstract":"The blind identification of a special class of nonlinear system is pursued in this paper. In particular a genetic algorithm is developed for blind identification of quadratic Volterra model excited by an unobservable input signal which can either be a stationary Gaussian process or an i.i.d process. This approach enables a nonlinear relationship between model kernels and output cumulants up to third order. Simulation results are presented to show good performance of this approach.","PeriodicalId":425397,"journal":{"name":"2007 IEEE International Conference on Signal Processing and Communications","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126594573","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 : 2007-11-01DOI: 10.1109/ICSPC.2007.4728331
A. Hamid, F. Cooray
This paper presents an analytic solution to the problem of radiation from an axisymmetric slot on a spheroid confocally coated with an isorefractive material, when the slot is excited by a delta gap source. The formulation is realized by expanding the electromagnetic field in each region in terms of spheroidal vector wave functions and a set of unknown expansion coefficients, and imposing boundary conditions at the interface between the surface of the spheroid and the isorefractive coating, as well as that between the coating and the medium exterior to the coating. This generates a set of simultaneous equations, the solution of which yields the unknown expansion coefficients. Results are presented as normalized power patterns and radiation patterns for both conventional isorefractive materials as well as for isorefractive metamaterials, to show the effects of the coating on the radiation from the antenna.
{"title":"Radiation from an Axisymmetric Slot on a Spheroid Coated with an Isorefractive Material and Excited by a Delta Gap Source","authors":"A. Hamid, F. Cooray","doi":"10.1109/ICSPC.2007.4728331","DOIUrl":"https://doi.org/10.1109/ICSPC.2007.4728331","url":null,"abstract":"This paper presents an analytic solution to the problem of radiation from an axisymmetric slot on a spheroid confocally coated with an isorefractive material, when the slot is excited by a delta gap source. The formulation is realized by expanding the electromagnetic field in each region in terms of spheroidal vector wave functions and a set of unknown expansion coefficients, and imposing boundary conditions at the interface between the surface of the spheroid and the isorefractive coating, as well as that between the coating and the medium exterior to the coating. This generates a set of simultaneous equations, the solution of which yields the unknown expansion coefficients. Results are presented as normalized power patterns and radiation patterns for both conventional isorefractive materials as well as for isorefractive metamaterials, to show the effects of the coating on the radiation from the antenna.","PeriodicalId":425397,"journal":{"name":"2007 IEEE International Conference on Signal Processing and Communications","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122159616","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：