Papers by Moataz El Ayadi
Language-independent call routing using the large margin estimation principle
Interspeech 2013
IEEE Transactions on Vehicular Technology, 2015
In this paper, we derive closed-form exact and asymptotic expressions for the symbol error rate (... more In this paper, we derive closed-form exact and asymptotic expressions for the symbol error rate (SER) as well as channel capacity when communicating over the Fox's H-function fading channel. The SER expressions are obtained for numerous practically-employed modulation schemes in case of single as well as three multiplebranch diversity receivers: maximal ratio combining (MRC), equal gain combining (EGC), and selection combining (SC). The derived exact expressions are given in terms of the univariate and multivariate Fox-H functions for which we provide a portable and efficient Python code. Since the Fox's H-function fading channel represents the most generalized fading model ever presented in the literature, the derived expressions subsume most of those previously presented for all the known simple and composite fading models. Moreover, easy-to-compute asymptotic expansions are provided so as to easily study the behavior of the SER and channel capacity at high values of the average signal-to-noise (SNR). The asymptotic expansions are also useful in comparing different modulation schemes and receiver diversity combiners. Numerical and simulation results are also provided to support the mathematical analysis and prove the validity of the obtained expressions.
IET Communications, 2016
In this paper, we revisit energy detection-based spectrum sensing cognitive radio systems operati... more In this paper, we revisit energy detection-based spectrum sensing cognitive radio systems operating over generalised fading channels. In particular, we derive closed-form exact expressions as well as lowand high-signal-to-noise ratio asymptotic expansions for the misdetection probability over the Fox's H-function fading channel. The closed-form expression is given in terms of the bivariate Fox's Hfunction and subsumes most of the expressions previously presented in the literature. Also, the obtained asymptotic expressions are very easy to compute and can be used to get various performance insights. We verified, theoretically and numerically, the validity of the exact expression for important special cases previously reported in the literature, namely the Nakagami-m and the extended generalised-K (EGK) fading distributions. Numerical results also demonstrate the high accuracy of the asymptotic expansions.
EURASIP journal on advances in signal processing
Gaussian mixture models (GMMs) are recently employed to provide a robust technique for speaker id... more Gaussian mixture models (GMMs) are recently employed to provide a robust technique for speaker identification. The determination of the appropriate number of Gaussian components in a model for adequate speaker representation is a crucial but difficult problem. This number is in fact speaker dependent. Therefore, assuming a fixed number of Gaussian components for all speakers is not justified. In this paper, we develop a procedure for roughly estimating the maximum possible model order above which the estimation of model parameters becomes unreliable. In addition, a theoretical measure, namely, a goodness of fit (GOF) measure is derived and utilized in estimating the number of Gaussian components needed to characterize different speakers. The estimation is carried out by exploiting the distribution of the training data for each speaker. Experimental results indicate that the proposed technique provides comparable results to other well-known model selection criteria like the minimum d...
Autoregressive models for text independent speaker identification in noisy environments
... In particular, I would like to thank Ahmed Shamy, Azmy Faisal, Ayman Abdel Rahman, Hatem Al-B... more ... In particular, I would like to thank Ahmed Shamy, Azmy Faisal, Ayman Abdel Rahman, Hatem Al-Beheiry, Hatem Zein El Din, Nizar Abdullah, and Rami Langar. Special thanks ... In partic-ular, I would like to thank Abbas Ahmadi, Sami Ullah, Akram Al Ghazali, Hanan ...
Dimensionality reduction for text-independent speaker identification using gaussian mixture model
2003 46th Midwest Symposium on Circuits and Systems, 2003
Reducing the dimensionality of the training and testing data is crucial for text-independent spea... more Reducing the dimensionality of the training and testing data is crucial for text-independent speaker identification tasks. In this paper, the performance of various dimensionality reduction techniques is evaluated for speaker identification systems using Gaussian mixture model (GMM) as the statistical classifier. An enhancement of the standard linear discriminant analysis (LDA) is proposed in which class distributions are assumed to follow
Genetic Resources and Crop Evolution, 2005
In this paper, we seek to enhance the identification performance of Gaussian Mixture Model (GMM)b... more In this paper, we seek to enhance the identification performance of Gaussian Mixture Model (GMM)based speaker identification systems in the presence of a limited amount of training data and a relatively large number of speakers. The performance is characterized by the identification accuracy, the identification time, and the model complexity. A new model order selection technique based on the Goodness of Fit (GOF) statistical test is proposed in order to increase the identification accuracy. This technique has shown to outperform other well known model order selection techniques like the Minimum Description Length (MDL) and the Akaike Information Criterion (AIC) in terms of the identification accuracy and the robustness against telephone channel degradation effects. In addition, the identification time is decreased by adapting the Linear Discriminative Analysis (LDA) feature extraction technique to fit our basic assumption of asymmetric multimodal distribution of the training data of each speaker. This modification results in a large decrease in the identification time with a little effect on the identification accuracy.
Novel Tight Closed-Form Bounds for the Symbol Error Rate of EGC and MRC Diversity Receivers Employing Linear Modulations Over $$\alpha -\mu $$ α - μ Fading
Wireless Personal Communications, 2013
Ict 2013, May 1, 2013
In this paper, we propose novel simple-to-calculate lower and upper bounds on the probability of ... more In this paper, we propose novel simple-to-calculate lower and upper bounds on the probability of error for dualbranch equal-gain combining (EGC) and maximal ratio combining (MRC) diversity receivers with α − µ fading and linear modulations. For deriving such bounds, we derive lower and upper bounds for the cumulative distribution function (CDF) of the sum of two independent and non identically distributed αµ random variables (RVs). The CDF bounds are given in the form of finite series of normalized incomplete Gamma functions and, unlike many in the literature, do not require any look up tables or solving transcendental equations to be obtained. We present extensive numerical results for different combinations of the parameters α and µ and show that the proposed bounds on the CDF and the probability of error are very tight when compared to the exact quantities.
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Papers by Moataz El Ayadi