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作者： Somayeh Mosleh Ali Akbar Tadaion Mostafa Derakhtian Signal Processing Laboratory Department of Electrical and Computer Engineering Yazd University Yazd Iran Department of Electrical Engineering Shiraz University Shiraz Iran

A key technology in cognitive radio (CR) is spectrum sensing that senses the spectrum and reports the available vacant channels. However, due to some effects such as fading or shadowing, an individual sensor may not be able to reliably detect the existence of a primary user (PU). Cooperative spectrum sensing that is proposed to solve such problem, uses a distributed detection system to overcome the severe decadent of received signal strength at some locations in the network. This paper considers the performance of a distributed Neyman-Pearson (N-P) detection system consisting of N sensors and a fusion center, in which the decision rules of the sensors have been given and the decisions of different sensors are mutually independent conditioned on both hypotheses. Theoretical analysis on the performance of this fusion center is carried out. We obtain the conditions for the fusion center to achieve an overall probability of detection that is greater than the local probability of detection of each sensor. Numerical results show that the AND, OR and majority decision fusion rules are the special cases of the N-P fusion rule.

关键词： Performance analysis Cognitive radio Chromium Frequency Sensor fusion Detectors Sensor systems Fading Intelligent networks Shadow mapping

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Decision Level Fusion of Colour Histogram Based Classifiers for Clustering of Mouth Area Images

Decision Level Fusion of Colour Histogram Based Classifiers ...

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International Conference on Digital Image processing, ICDIP

作者： Fahimeh Salimi Mohammad T. Sadeghi Signal Processing Research Laboratory Department of Electrical and Computer Engineering Engineering Research Centre Yazd University Yazd Iran

It is well known that in many situations combining diverse classifiers can improve the performance of a classification system. In this paper, a new histogram based lip segmentation technique is proposed considering local kernel histograms in different illumination invariant colour spaces. The histogram is computed in local areas using two Gaussian kernels; one in the colour space and the other in the spatial domain. Using the estimated histogram, the posterior probability associated to non-lip class is then computed for each pixel. This process is performed considering different colour spaces. A weighted averaging method is then used for fusing the posterior probability values. As the result a new score is obtained which is used for labeling the pixels as lip or non-lip. The advantage of the proposed method is that the segmentation process is totally unsupervised. So, the method is robust against different variations such as variation in lip shape, skin colour, facial hair, illumination, etc. Moreover, an improved performance is achieved by fusing colour information.

关键词： Histograms Mouth Kernel Lighting Diversity reception Image segmentation Color Labeling Robustness Shape

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Incremental learning in nonstationary environments with controlled forgetting

Incremental learning in nonstationary environments with cont...

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International Joint Conference on Neural Networks (IJCNN)

作者： Ryan Elwell Robi Polikar Signal Processing and Pattern Recognition Laboratory Electrical and Computer Engineering Department Rowan University Glassboro NJ USA

We have recently introduced an incremental learning algorithm, called Learn ++ .NSE, designed for Non-Stationary Environments (concept drift), where the underlying data distribution changes over time. With each dataset drawn from a new environment, Learn ++ .NSE generates a new classifier to form an ensemble of classifiers. The ensemble members are combined through a dynamically weighted majority voting, where voting weights are determined based on classifiers' age-adjusted accuracy on current and past environments. Unlike other ensemble-based concept drift algorithms, Learn ++ .NSE does not discard prior classifiers, allowing potentially cyclical environments to be learned more effectively. While Learn ++ .NSE has been shown to work well on a variety of concept drift problems, a potential shortcoming of this approach is the cumulative nature of the ensemble size. In this contribution, we expand our analysis of the algorithm to include various ensemble pruning methods to introduce controlled forgetting. Error or age-based pruning methods have been integrated into the algorithm to prevent potential out-voting from irrelevant classifiers or simply to save memory over an extended period of time. Here, we analyze the tradeoff between these precautions and the desire to handle recurring contexts (cyclical data). Comparisons are made using several scenarios that introduce various types of drift.

关键词： Neutron spin echo Algorithm design and analysis Voting

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Whitening-rotation-based semi-blind estimation of MIMO FIR channels

Whitening-rotation-based semi-blind estimation of MIMO FIR c...

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International Conference on Wireless communications and signal processing (WCSP)

作者： Qingwu Zhang Wei-Ping Zhu Qingmin Meng Institute of Signal Processing and Transmission Nanjing University of Posts and Telecommunications Nanjing China Centre of Signal Processing and Communications Department of Electrical and Computer Engineering Concordia University Montreal QUE Canada

In this paper, a new semi-blind algorithm is presented for the estimation of Multiple-Input Multiple-Output (MIMO) Finite Impulse Response (FIR) channels. First, by using the MIMO linear prediction (LP), the whitening matrix is estimated blindly from the received data. The rotation matrix is then estimated by employing pilot symbols. The proposed method is validated through computer simulation-based experimentations, showing a high estimation accuracy as compared to the LS method in terms of the MSE of the channel estimate.

关键词： MIMO Finite impulse response filter Channel estimation signal processing algorithms Receiving antennas Matrix decomposition Maximum likelihood estimation Telecommunication computing Computational modeling computer simulation

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Comparison between noise reduction algorithms for speech signals using auditory masking effects

Comparison between noise reduction algorithms for speech sig...

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IEEE GCC Conference & Exhibition

作者： Mehdi Yektaeian Rassoul Amirfattahi Digital Signal Processing Research Laboratory Department of Electrical and Computer Engineering Isfahan University of Technology Isfahan Iran

Auditory masking is aggressively exploited by algorithms used for the lossy compression of audio signals. In compression of audio signals, the intent is to hide the noise introduced by the coding below the masking threshold, thus making the noise inaudible. This will render the coding process transparent, enabling better compression without audible degradation of the signal. In this article, we show that using masking properties of the hearing system allows for improved noise reduction. A novel method for noise reduction in speech signals is proposed. This method is shown to outperform non-auditory based methods, and compares well with other perceptually motivated noise reduction methods. It is found that the proposed method, Soulodre's PNRF combined with the ITU's PEAQ auditory model, have more musical noise but less signal distortion than the method proposed by Tsoukalas, which obtain marginally better results in informal testing results.

关键词： signal to noise ratio Noise reduction Speech Speech enhancement Masking threshold

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Real-time processing of simplex growing algorithm

Real-time processing of simplex growing algorithm

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2009 IEEE International Geoscience and Remote Sensing Symposium, IGARSS 2009

作者： Wu, Chao-Cheng Chang, Chein-I. Ren, Husen Chang, Yang Lang Remote Sensing Signal and Image Processing Laboratory Department of Computer Science and Electrical Engineering University of Maryland Baltimore County Baltimore MD 21250 United States Department of Electrical Engineering National Chung Hsing University Taichung Taiwan Center for Space and Remote Sensing Research National Central University Jhong-Li Tao-Yuan Taiwan Department of Electrical Engineering National Taipei University of Technology Taipei Taiwan

ISBN: (纸本)9781424433957

Simplex growing algorithm (SGA) was recently developed as an alternative to the N-finder algorithm (N-FINDR) which is shown to be a promising endmember extraction technique. This paper further extends the SGA to a real-time processing algorithm, referred to as real-time SGA (RT SGA) that can effectively address four major issues arising in practical implementation for N-FINDR, (1) use of random initial endmembers which causes inconsistent final results, (2) very high computational complexity which results from an exhaustive search for finding all endmembers simultaneously, (3) requirement of dimensionality reduction because of enormous data volumes to be processed and (4) lack of real-time capability. ©2009 IEEE.

关键词： Extraction

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Joint user scheduling and beamforming for underlay cognitive radio systems

Joint user scheduling and beamforming for underlay cognitive...

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Asia-Pacific Conference on communications

作者： Wenhui Zong Sen Shao Qingmin Meng Weiping Zhu Institute of Signal and Transmission Nanjing University of Posts and Telecommunications Nanjing China National Mobile Communications Research Laboratory South-East University Nanjing China Centre for Signal Processing and Communications Department of Electrical and Computer Engineering Concordia University Montreal QUE Canada

ISBN: (纸本)9781424447848

In this paper, we consider underlay cognitive radio systems in which secondary users coexist with users in primary networks whose radio band is licensed. The secondary subnetwork comprising the cognitive users utilizes the cognitive radio technology to make opportunistic access to the licensed spectrum that primary users own. In this scheme, we discuss the issue of joint user scheduling and beamforming in order to make sure that received interferences at the primary users maintain below an affordable threshold level. The user scheduling includes two procedures: 1) primary users scheduling; 2) secondary users scheduling. However, these two steps are carried out coordinately and the selected primary user and corresponding cognitive users can be obtained. In addition, Zero-forcing Beamforming (ZFBF) and antenna selection are integrated into our scheme where the former is used to support multiple concurrent streams transmission and the latter is used to reduce the feedback in the uplink of the secondary system. Our performance results show that the proposed scheme can significantly improve the throughput of the whole cognitive radio networks.

关键词： Array signal processing Cognitive radio Mobile communication Wireless communication Interference constraints Receiving antennas Downlink signal processing Transmitting antennas Throughput

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A Near Fair User Scheduling Scheme in Cognitive Radio Networks

A Near Fair User Scheduling Scheme in Cognitive Radio Networ...

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International Conference on Wireless communications, Networking and Mobile Computing (WiCom)

作者： Qingmin Meng Wenhui Zong Sen Shao Weiping Zhu Baoyu Zheng National Mobile Communications Research Laboratory South-East University Nanjing China Institute of Signal and Transmission Nanjing University of Posts and Telecommunications Nanjing China Centre of Signal Processing and Communications Department of Electrical and Computer Engineering Concordia University Montreal QUE Canada

Nowadays, cognitive radio technique has been acknowledged as a smart and potential method to improve the spectrum utilization. In this work, we investigate a cognitive radio communication scheme, where a number of cognitive users, each with multiple antennas, can share the spectrum with the primary user. To decrease the inter-user interference, zero-forcing beamforming (ZFBF) is considered. We presented a design of three-step selection for both the cognitive users and their antennas at receiver. In the first step of the studied scheme, antennas-selection is performed to based on a certain algorithm and then user-selection is performed based on Proportional Fair algorithm. Next the active set of cognitive users is selected according to the correlation between the users in the third step. Simulation results show that at the expense of some sum-rate loss, our proposed scheme can realize near fair resource allocation among the cognitive users as well as the decrease of the interference to the primary user and of the feedback.

关键词： Cognitive radio Receiving antennas Interference Downlink Scheduling Antenna feeds Base stations signal processing Mobile communication Array signal processing

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Editorial: Game theory in signal processing and communications

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Eurasip Journal on Advances in signal processing 2009年 2009卷

作者： Jorswieck, Eduard A. Boche, Holger Han, Zhu Larsson, Erik G. Department of Mobile Communications School of Electrical Engineering and Computer Sciences Technical University of Berlin Berlin Germany Wireless Networking Signal Processing and Security Lab Department of Electrical and Computer Engineering University of Houston Houston TX 77004 United States Linkping University SE-581 83 Linkping Sweden Communications Laboratory Faculty of Electrical Engineering and Information Technology Dresden University of Technology 01062 Dresden Germany

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signal processing for neural spike trains

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Computational intelligence and neuroscience 2010年第1期2010卷 698751页

作者： Theodore W Berger Zhe Sage Chen Andrzej Cichocki Karim G Oweiss Rodrigo Quian Quiroga Nitish V Thakor Department of Biomedical Engineering Viterbi School of Engineering University of Southern California Los Angeles CA 90089 USA Neuroscience Statistics Research Laboratory Massachusetts Institute of Technology Cambridge MA 02139 USA Laboratory for Advanced Brain Signal Processing RIKEN Brain Science Institute Wako-shi Saitama 351-0198 Japan Department of Electrical and Computer Engineering Michigan State University MI 48824 USA Department of Engineering University of Leicester Leicester LE1 7RH UK School of Medicine Johns Hopkins University Baltimore MD 21205 USA

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