Pub Date : 2012-04-03DOI: 10.1109/NCC.2012.6176793
R. K. Jha, R. Chouhan, P. Biswas
In this paper, a nonlinear non-dynamic stochastic resonance-based technique has been proposed for enhancement of dark and low contrast images. A low contrast image is treated as a subthreshold signal and noise-enhanced signal processing is applied to improve its contrast. The proposed technique uniquely utilizes addition of external noise to neutralize the effect of internal noise (due to insufficient illumination) of a low contrast image. Random noise is added repeatedly to an image and is successively hard-thresholded followed by overall averaging. By varying the noise intensities, noise induced resonance is obtained at a particular optimum noise intensity. Performance of the proposed technique has been investigated for four types of noise distributions - gaussian, uniform, poisson and gamma. Quantitative evaluation of their performances have been done in terms of contrast enhancement factor, color enhancement and perceptual quality measure. Comparison with other existing spatial domain techniques shows that the proposed technique gives remarkable enhancement while ascertaining good perceptual quality.
{"title":"Noise-induced contrast enhancement of dark images using non-dynamic stochastic resonance","authors":"R. K. Jha, R. Chouhan, P. Biswas","doi":"10.1109/NCC.2012.6176793","DOIUrl":"https://doi.org/10.1109/NCC.2012.6176793","url":null,"abstract":"In this paper, a nonlinear non-dynamic stochastic resonance-based technique has been proposed for enhancement of dark and low contrast images. A low contrast image is treated as a subthreshold signal and noise-enhanced signal processing is applied to improve its contrast. The proposed technique uniquely utilizes addition of external noise to neutralize the effect of internal noise (due to insufficient illumination) of a low contrast image. Random noise is added repeatedly to an image and is successively hard-thresholded followed by overall averaging. By varying the noise intensities, noise induced resonance is obtained at a particular optimum noise intensity. Performance of the proposed technique has been investigated for four types of noise distributions - gaussian, uniform, poisson and gamma. Quantitative evaluation of their performances have been done in terms of contrast enhancement factor, color enhancement and perceptual quality measure. Comparison with other existing spatial domain techniques shows that the proposed technique gives remarkable enhancement while ascertaining good perceptual quality.","PeriodicalId":178278,"journal":{"name":"2012 National Conference on Communications (NCC)","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124963843","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 : 2012-04-03DOI: 10.1109/NCC.2012.6176746
N. H. Potty, R. Velmurugan, P. Rao
Several researchers have established the superior performance of spatial audio over monaural audio in multi-talker environments. The advantage provided by spatial audio can be incorporated in an audio teleconferencing system for an enhanced user experience. In our earlier work, a novel scheme for the spatial rendition of audio in an audio teleconferencing situation was proposed based on the concept of Minimum Audible Angle (MAA). We provide the basic architecture for a multi-talker teleconferencing system that uses the proposed scheme with independent clients that facilitate speaking, listening or both. The software stack that runs on each client is capable of receiving, sending and processing of audio signals and operates in real-time. The implementation is done in Java, using the Java Media Framework (JMF) for capturing and playback of the audio signal. RTP (Real-time Transport Protocol) protocols are used to ensure real-time transmission and reception over the network.
一些研究人员已经建立了空间音频在多话务员环境下优于单声音频的性能。空间音频所提供的优势可以并入音频远程会议系统中，以增强用户体验。在我们早期的工作中，我们提出了一种基于最小可听角(MAA)概念的音频远程会议中音频空间再现的新方案。我们提供了一个多讲话者远程会议系统的基本架构，该系统使用所提出的方案，具有独立的客户端，可以促进说，听或两者兼而有之。在每个客户端上运行的软件栈能够接收、发送和处理音频信号，并实时运行。该实现是在Java中完成的，使用Java媒体框架(JMF)捕获和播放音频信号。RTP (Real-time Transport Protocol，实时传输协议)协议用于保证网络的实时传输和接收。
{"title":"Architecture of a teleconference system based on Minimum Audible Angle","authors":"N. H. Potty, R. Velmurugan, P. Rao","doi":"10.1109/NCC.2012.6176746","DOIUrl":"https://doi.org/10.1109/NCC.2012.6176746","url":null,"abstract":"Several researchers have established the superior performance of spatial audio over monaural audio in multi-talker environments. The advantage provided by spatial audio can be incorporated in an audio teleconferencing system for an enhanced user experience. In our earlier work, a novel scheme for the spatial rendition of audio in an audio teleconferencing situation was proposed based on the concept of Minimum Audible Angle (MAA). We provide the basic architecture for a multi-talker teleconferencing system that uses the proposed scheme with independent clients that facilitate speaking, listening or both. The software stack that runs on each client is capable of receiving, sending and processing of audio signals and operates in real-time. The implementation is done in Java, using the Java Media Framework (JMF) for capturing and playback of the audio signal. RTP (Real-time Transport Protocol) protocols are used to ensure real-time transmission and reception over the network.","PeriodicalId":178278,"journal":{"name":"2012 National Conference on Communications (NCC)","volume":"53 4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130360695","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 : 2012-04-03DOI: 10.1109/NCC.2012.6176775
Deepak Baby, S. R. Pillai
Compressed Sensing deals with recovering sparse signals from a relatively small number of linear measurements. Several algorithms exists for data recovery from the compressed measurements, particularly appealing among these is the greedy approach known as Orthogonal Matching Pursuit (OMP). In this paper, we propose a modified OMP based algorithm called Ordered Orthogonal Matching Pursuit (Ordered OMP). Ordered OMP is conceptually simpler and provides an improved performance when compared to OMP.
{"title":"Ordered Orthogonal Matching Pursuit","authors":"Deepak Baby, S. R. Pillai","doi":"10.1109/NCC.2012.6176775","DOIUrl":"https://doi.org/10.1109/NCC.2012.6176775","url":null,"abstract":"Compressed Sensing deals with recovering sparse signals from a relatively small number of linear measurements. Several algorithms exists for data recovery from the compressed measurements, particularly appealing among these is the greedy approach known as Orthogonal Matching Pursuit (OMP). In this paper, we propose a modified OMP based algorithm called Ordered Orthogonal Matching Pursuit (Ordered OMP). Ordered OMP is conceptually simpler and provides an improved performance when compared to OMP.","PeriodicalId":178278,"journal":{"name":"2012 National Conference on Communications (NCC)","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123113065","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 : 2012-04-03DOI: 10.1109/NCC.2012.6176772
S. Gupta, V. Bhatia, L. C. Mangal
The paper presents FPGA implementation of GMSK (BT = 0.3) transceiver that uses a non-coherent sequence detection scheme. The receiver has a fairly low complexity 4-state trellis. Additional complexity reduction has been done through novel optimizations in phase state update, metric update and non-coherent recursive phase reference calculations. The receiver outperforms the non-coherent binary cross-correlator demodulator [4] by more than 4 dB in AWGN environment. It is robust against moderate carrier frequency offset variations up to 4% of symbol rate with marginal performance degradation up to 1.5 dB.
{"title":"An efficient FPGA implementation of GMSK (BT=0.3) transceiver with non coherent sequence detection for tactical V/UHF waveforms","authors":"S. Gupta, V. Bhatia, L. C. Mangal","doi":"10.1109/NCC.2012.6176772","DOIUrl":"https://doi.org/10.1109/NCC.2012.6176772","url":null,"abstract":"The paper presents FPGA implementation of GMSK (BT = 0.3) transceiver that uses a non-coherent sequence detection scheme. The receiver has a fairly low complexity 4-state trellis. Additional complexity reduction has been done through novel optimizations in phase state update, metric update and non-coherent recursive phase reference calculations. The receiver outperforms the non-coherent binary cross-correlator demodulator [4] by more than 4 dB in AWGN environment. It is robust against moderate carrier frequency offset variations up to 4% of symbol rate with marginal performance degradation up to 1.5 dB.","PeriodicalId":178278,"journal":{"name":"2012 National Conference on Communications (NCC)","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127625804","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 : 2012-04-03DOI: 10.1109/NCC.2012.6176738
N. S. Chaitanya, S. Ramachandram, K. Ramakrishna, S. S. Skandha, B. Padmavathi
Grid computing has recently gained tremendous momentum but still is in its infancy. It has the potential for significant cost reduction and the increased operating efficiencies in computing. Although security issues are delaying its fast adoption, grid computing is an unstoppable force and we need to provide security mechanisms to ensure its secure adoption. In this paper, we propose a comprehensive security framework for grid computing environments. We also discuss challenges, existing solutions, approaches, and future work needed to provide a trustworthy grid computing environment. The demand of storage space is an issue for record digitalization. Mass storage and reliability of the Grid system do offer one solution for electronic records. In this paper we present a new method of storing electronic records distributed at different systems site using RAID-3 algorithm. By RAID-3, the segmented data stored at each system is meaningless and cannot be used alone. This will enhance the security & Privacy of data.
{"title":"RAID technology for secured grid computing environments","authors":"N. S. Chaitanya, S. Ramachandram, K. Ramakrishna, S. S. Skandha, B. Padmavathi","doi":"10.1109/NCC.2012.6176738","DOIUrl":"https://doi.org/10.1109/NCC.2012.6176738","url":null,"abstract":"Grid computing has recently gained tremendous momentum but still is in its infancy. It has the potential for significant cost reduction and the increased operating efficiencies in computing. Although security issues are delaying its fast adoption, grid computing is an unstoppable force and we need to provide security mechanisms to ensure its secure adoption. In this paper, we propose a comprehensive security framework for grid computing environments. We also discuss challenges, existing solutions, approaches, and future work needed to provide a trustworthy grid computing environment. The demand of storage space is an issue for record digitalization. Mass storage and reliability of the Grid system do offer one solution for electronic records. In this paper we present a new method of storing electronic records distributed at different systems site using RAID-3 algorithm. By RAID-3, the segmented data stored at each system is meaningless and cannot be used alone. This will enhance the security & Privacy of data.","PeriodicalId":178278,"journal":{"name":"2012 National Conference on Communications (NCC)","volume":"196 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133858569","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 : 2012-04-03DOI: 10.1109/NCC.2012.6176835
R. Jose, K. Hari
A joint Maximum Likelihood (ML) estimation algorithm for the synchronization impairments such as Carrier Frequency Offset (CFO), Sampling Frequency Offset (SFO) and Symbol Timing Error (STE) in single user MIMO-OFDM system is investigated in this work. A received signal model that takes into account the nonlinear effects of CFO, SFO, STE and Channel Impulse Response (CIR) is formulated. Based on the signal model, a joint ML estimation algorithm is proposed. Cramer-Rao Lower Bound (CRLB) for the continuous parameters CFO and SFO is derived for the cases of with and without channel response effects and is used to compare the effect of coupling between different estimated parameters. The performance of the estimation method is studied through numerical simulations.
{"title":"Joint estimation of synchronization impairments in MIMO-OFDM system","authors":"R. Jose, K. Hari","doi":"10.1109/NCC.2012.6176835","DOIUrl":"https://doi.org/10.1109/NCC.2012.6176835","url":null,"abstract":"A joint Maximum Likelihood (ML) estimation algorithm for the synchronization impairments such as Carrier Frequency Offset (CFO), Sampling Frequency Offset (SFO) and Symbol Timing Error (STE) in single user MIMO-OFDM system is investigated in this work. A received signal model that takes into account the nonlinear effects of CFO, SFO, STE and Channel Impulse Response (CIR) is formulated. Based on the signal model, a joint ML estimation algorithm is proposed. Cramer-Rao Lower Bound (CRLB) for the continuous parameters CFO and SFO is derived for the cases of with and without channel response effects and is used to compare the effect of coupling between different estimated parameters. The performance of the estimation method is studied through numerical simulations.","PeriodicalId":178278,"journal":{"name":"2012 National Conference on Communications (NCC)","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133089403","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 : 2012-04-03DOI: 10.1109/NCC.2012.6176776
Mohit K. Sharma, A. Rajesh, P. K. Bora
We address an important issue in the design of concentric permutation code based vector quantizers to select the optimal integer partitions. We establish that, for concentric permutation code based vector quantizers, the optimum integer partitions exhibit monotonicity with its index. In addition, a reduced complexity encoding scheme for concentric permutation code based vector quantizers is presented.
{"title":"On concentric permutation code based vector quantizer design","authors":"Mohit K. Sharma, A. Rajesh, P. K. Bora","doi":"10.1109/NCC.2012.6176776","DOIUrl":"https://doi.org/10.1109/NCC.2012.6176776","url":null,"abstract":"We address an important issue in the design of concentric permutation code based vector quantizers to select the optimal integer partitions. We establish that, for concentric permutation code based vector quantizers, the optimum integer partitions exhibit monotonicity with its index. In addition, a reduced complexity encoding scheme for concentric permutation code based vector quantizers is presented.","PeriodicalId":178278,"journal":{"name":"2012 National Conference on Communications (NCC)","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130952023","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 : 2012-04-03DOI: 10.1109/NCC.2012.6176764
G. Sharma, K. Rajeswari
MIMO (Multiple-Input Multiple-Output) Radars have received considerable attention over the last decade due to their enhanced performance potential. Unlike phased array radar, MIMO radar transmits orthogonal waveforms via its transmitting antennas to improve separability of individual returns at the receiver elements. In this paper, an alternate method for generating four-phase sequences with good autocorrelation and cross correlation properties is proposed. The advantages of the proposed scheme include constant envelope, finite alphabet, large family and efficient structure for generation.
{"title":"Four-phase orthogonal code design for MIMO radar systems","authors":"G. Sharma, K. Rajeswari","doi":"10.1109/NCC.2012.6176764","DOIUrl":"https://doi.org/10.1109/NCC.2012.6176764","url":null,"abstract":"MIMO (Multiple-Input Multiple-Output) Radars have received considerable attention over the last decade due to their enhanced performance potential. Unlike phased array radar, MIMO radar transmits orthogonal waveforms via its transmitting antennas to improve separability of individual returns at the receiver elements. In this paper, an alternate method for generating four-phase sequences with good autocorrelation and cross correlation properties is proposed. The advantages of the proposed scheme include constant envelope, finite alphabet, large family and efficient structure for generation.","PeriodicalId":178278,"journal":{"name":"2012 National Conference on Communications (NCC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130163900","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 : 2012-04-03DOI: 10.1109/NCC.2012.6176910
C. Anilkumar, D. Khan, A. Bansal, A. Khandelwal, S. Pathak
Communication through fading channels with conventional signal constellation has a limitation that the nearby points may lead to wrong symbol detection even if any one dimension fades. This limitation can be overcome by phase rotation of symbols where each symbol is rotated by a rotation matrix. In the new constellation, each symbol attains unique real and imaginary components which imply higher diversity order, and thus, it may result in higher noise margin. Though performance gain can be achieved through the selection of optimum rotation matrix, the high decimal precision of the rotated symbols demands larger memory support and processing effort due to their representation by unquantized real numbers. Quantization of the rotated symbols is a solution for this problem, but it may degrade the bit-error performance. This paper investigates the tradeoff between the bit-error performance of 64-QAM and the compromise in the precision of rotation.
{"title":"Quantized modulation diversity for 64-QAM","authors":"C. Anilkumar, D. Khan, A. Bansal, A. Khandelwal, S. Pathak","doi":"10.1109/NCC.2012.6176910","DOIUrl":"https://doi.org/10.1109/NCC.2012.6176910","url":null,"abstract":"Communication through fading channels with conventional signal constellation has a limitation that the nearby points may lead to wrong symbol detection even if any one dimension fades. This limitation can be overcome by phase rotation of symbols where each symbol is rotated by a rotation matrix. In the new constellation, each symbol attains unique real and imaginary components which imply higher diversity order, and thus, it may result in higher noise margin. Though performance gain can be achieved through the selection of optimum rotation matrix, the high decimal precision of the rotated symbols demands larger memory support and processing effort due to their representation by unquantized real numbers. Quantization of the rotated symbols is a solution for this problem, but it may degrade the bit-error performance. This paper investigates the tradeoff between the bit-error performance of 64-QAM and the compromise in the precision of rotation.","PeriodicalId":178278,"journal":{"name":"2012 National Conference on Communications (NCC)","volume":"36 12","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114021574","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 : 2012-04-03DOI: 10.1109/NCC.2012.6176749
H. Vangala, R. Meshram, V. Sharma
We consider the problem of joint routing, scheduling and power control in a multihop wireless network when the nodes have multiple antennas. We present an iterative scheme to compute achievable rates in the interference environment of the network using SINR model. The solution methods have a high computational complexity. Thus we also provide an efficient low complexity sub-optimal solution. We show that the multiple antennas provide linear gain in system throughput.
{"title":"Joint routing, scheduling and power control for multihop MIMO networks","authors":"H. Vangala, R. Meshram, V. Sharma","doi":"10.1109/NCC.2012.6176749","DOIUrl":"https://doi.org/10.1109/NCC.2012.6176749","url":null,"abstract":"We consider the problem of joint routing, scheduling and power control in a multihop wireless network when the nodes have multiple antennas. We present an iterative scheme to compute achievable rates in the interference environment of the network using SINR model. The solution methods have a high computational complexity. Thus we also provide an efficient low complexity sub-optimal solution. We show that the multiple antennas provide linear gain in system throughput.","PeriodicalId":178278,"journal":{"name":"2012 National Conference on Communications (NCC)","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116474632","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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