Browsing by Author "Hamam, Habib"
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Item Advanced key distribuation center algorithm (AKDC)(2010) Abuazab, Hussam Hussein; Dahmane, Adel Omar; Hamam, HabibItem Auditory-based subband blind source separation using sample-by-sample and Infomax algorithms(2010) Salem, Abderraouf Ben; Selouani, Sid Ahmed; Hamam, HabibWe present a new subband decomposition method for the separation of convolutive mixtures of speech. This method uses a sample-by-sample algorithm to perform the subband decomposition by mimicking the processing performed by the human ear. The unknown source signals are separated by maximizing the entropy of a transformed set of signal mixtures through the use of a gradient ascent algorithm. Experimental results show the efficiency of the proposed approach in terms of signal-to-interference ratio. Compared with the fullband method that uses the Infomax algorithm, our method shows an important improvement of the output signal-to-noise ratio when the sensor inputs are severely degraded by additive noise.Item An autoregressive time delay neural network for speech steganalysis(Institute of Electrical and Electronics Engineers Inc., 2012) Rekik, Siwar; Selouani, Sid-Ahmed; Guerchi, Driss; Hamam, HabibHiding a secret message in speech signal, called steganography, is used to provide secure communication. The detection of hidden information in the transmitted message called steganalysis. The purpose of steganalysis is to identify the presence of embedded information, and does not actually attempt to extract or decode the hidden data. An automated method is required for detecting the existence of hidden message, since the huge amount of channeled information. However, the development and evaluation of steganalysis algorithms is a challenging task. In this paper we advocate a new steganalysis technique to classify a speech as having hidden information or not, using a powerful and sophisticated classifier called Autoregressive Time Delay Neural Network (AR-TDNN). The originality of this AR-TDNN is its quite ability to detect secret messages hidden with different steganographic algorithms, although the variation of detection rate depends on the particular hiding techniques and amount of hidden information. © 2012 IEEE.Item Comparative study of digital audio steganography techniques(2012) Djebbar, Fatiha; Ayad, Beghdad; Meraim, Karim Abed; Hamam, HabibThe rapid spread in digital data usage in many real life applications have urged new and effective ways to ensure their security. Efficient secrecy can be achieved, at least in part, by implementing steganograhy techniques. Novel and versatile audio steganographic methods have been proposed. The goal of steganographic systems is to obtain secure and robust way to conceal high rate of secret data. We focus in this paper on digital audio steganography, which has emerged as a prominent source of data hiding across novel telecommunication technologies such as covered voice-over-IP, audio conferencing, etc. The multitude of steganographic criteria has led to a great diversity in these system design techniques. In this paper, we review current digital audio steganographic techniques and we evaluate their performance based on robustness, security and hiding capacity indicators. Another contribution of this paper is the provision of a robustness-based classification of steganographic models depending on their occurrence in the embedding process. A survey of major trends of audio steganography applications is also discussed in this paper. © 2012 Djebbar et al.; licensee Springer.Item Controlled distortion for high capacity data-in-speech spectrum steganography(Institute of Electrical and Electronics Engineers Inc., 2010) Djebbar, Fatiha; Hamam, Habib; Abed-Meraim, Karim; Guerchi, DrissMethods applied to ensure privacy of digital data became essential in many real life applications. Efficient secrecy can be achieved, at least in part, by implementing steganography techniques. In this paper, we present a technique that limits the impact of high data capacity embedding on the quality of stego wideband speech. Our method uses the energy of each frequency bin component to determine the maximum number of bits that can be confined without inducing any noticeable distortion on the cover speech. To guarantee good quality of stego speech, the embedding in the selected frequency components occurs below a well defined distortion level to limit the impact of the hiding on the stego-speech. The algorithm uses multiple parameters that can be adjusted by the sender to render the steganalysis work more challenging. The objective and subjective results show that this approach is robust to noise addition and maintains a very good quality of the cover signal while achieving high hiding capacity. © 2010 IEEE.Item A cooperative and conversational virtual agent for M-commerce applications(Institute of Electrical and Electronics Engineers Inc., 2009) Rekik, Siwar; Selouani, Sid-Ahmed; Hamam, HabibThe aim of this paper is to present a cooperative approach to improve the Human-System spoken dialogues. The main advantage of the proposed approach is its ability to reach both of the user and the system goals more efficiently. The strategy that underlines our system is well adapted to the mobile applications since it involves effective spoken exchanges to reach the users' and system mutual goals. The proposed fram ework is built in order to use the Hidden Markov Models (HMMs) based CMU-Sphinx speech recognition engine f or mobile communications. To evaluate our approach a case-study in the M-trading field is considered. The analysis of the case study shows the efficiency ofour strategy in comparison with the usual ones. ©2009 IEEE.Item Deepkover - an adaptive artful intelligent assistance system for cognitively impaired people(Taylor and Francis Ltd., 2010) Najjar, Mehdi; Courtemanche, Francois; Hamam, Habib; Mayers, AndreThis article presents a novel modular adaptive artful intelligent assistance system for cognitively and/or memory impaired people engaged in the realisation of their activities of daily living (ADLs). The goal of this assistance system is to help disabled persons moving/evolving within a controlled environment in order to provide logistic support in achieving their ADLs. Empirical results of practical tests are presented and interpreted. Some deductions about the key features that represent originalities of the assistance system are drawn and future works are announced. © 2010 Taylor & Francis Group, LLC.Item Design and formal validation of a mutual authentication protocol for RFID technology(2010) Fennani, Bassem; Dahmane, Adel Omar; Hamam, HabibItem Dynamic energy based text-in-speech spectrum hiding using speech masking properties(Institute of Electrical and Electronics Engineers Inc., 2010) Djebbar, Fatiha; Abed-Meraim, Karim; Guerchi, Driss; Hamam, HabibIn this paper we present a new method for text-in-speech Fast Fourier Transform (FFT) based steganography. Our method exploits high energetic magnitude frequency components of speech spectrum to hide the secret text. The energy level of each magnitude component is evaluated, and considered only if it is high enough to embed secret data. A frequency maskmg threshold is then calculated for each energetic frequency magnitude component to decide where to embed the secret text. As a result, the initial energy of the cover speech spectrum is slightly modified and the dIstortion error is always kept under the mask. The objective and subjective evaluations show that introducing the energy-based frequency masking 0l?ens new frontiers in text-in-speech steganography since hIgher bit rate text embedding was achieved while obtaining a stego-speech with unnoticeable distortion. © 2010 IEEE.Item FPGA implementation of floating-point complex matrix inversion based on GAUSS-JORDAN elimination(2013) Moussa, Sherif; Razik, Ahmed M. Abdel; Dahmane, Adel Omar; Hamam, HabibThis work presents the architecture of an optimized complex matrix inversion using GAUSS-JORDAN elimination (GJ-elimination) on FPGA with single precision floating-point representation to be used in MIMO-OFDM receiver. This module consists of single precision floating point arithmetic components and control unit which perform the GJ-elimination algorithm. The proposed architecture performs the GJ-elimination for complex matrix element by element. Only critical arithmetic operations are calculated to get the needed values without performing all the arithmetic operations of the GJ-elimination algorithm. This results in a reduced hardware resources and execution time. © 2013 IEEE.Item A highly robust audio hashing system using auditory-based front-end processing(Institute of Electrical and Electronics Engineers Inc., 2009) Salem, Abderraouf Ben; Selouani, Sid-Ahmed; Hamam, Habib; Caelen, JeanIn this paper, a robust perceptual audio hashing system is presented. A model of the human auditory system is used to extract robust features from the outputs of a non-linear filter bank that mimics the human basilar membrane. Experiments on various audio excerpts show that this new ear-based frontend processing provides very effective hash values. The proposed audio hashing system performs very satisfactorily in identification and it turned out very resilient to a large variety of severe audio attacks. ©2009 IEEE.Item Intensity based self-imaging(OSA - The Optical Society, 2010) Hamam, HabibWe propose an iterative method to optimize the phase profile of the initial field so that its intensity profile is observed periodically along the longitudinal (propagation) axis. The new method is inspired from the Gerchberg-Saxton technique, where the Fresnel transform is used, instead of the Fourier transform, for retrieving the phase profile of several light distributions (for example, 15 planes), instead of a Fourier pair of distributions. The additional challenge, with respect to the conventional Gerchberg-Saxton technique, is that the planes where constraints are applied number more than two. It turned out that when the number of periods increased, the spectrum of the obtained initial field converges toward including Montgomery's rings (self-imaging condition). © 2010 Optical Society of America.Item MIMO-OFDM scheme based on parity bit selected spreading(Institute of Electrical and Electronics Engineers Inc., 2012) Moussa, Sherif; Dahmane, Adel Omar; D'Amours, Claude; Hamam, HabibIn this paper, a novel transmission scheme is developed to effectively combine parity bit selected spreading technique and MIMO-OFDM to obtain improved bit error rate performance in the presence of frequency selective fading channels with low system complexity. Unlike conventional MIMO-OFDMA, where users are separated in different frequency bands (subchannels), and each user is coded separately using STBC or SFBC, the proposed new scheme enables multi access by joint code design across multiple antennas, subcarriers, and users. Such system will benefit from the combined space and frequency domain freedom as well as multiuser diversity. Hence, better spectrum efficiency is achieved while improving bit error rate performance with respect to signal-to- interference ratio. © 2012 IEEE.Item MIMO-OFDM scheme based on permutation spreading(Institute of Electrical and Electronics Engineers Inc., 2012) Moussa, Sherif; Dahmane, Adel Omar; D'Amours, Claude; Hamam, HabibIn this paper, a novel transmission scheme is developed to effectively combine permutation spreading technique with MIMO-OFDM to obtain improved bit error rate performance in the presence of frequency selective fading channels with low system complexity. Unlike conventional MIMO-OFDMA, where users are separated in different frequency bands (subchannels), and each user is coded separately using STBC or SFBC, the proposed new scheme enables multi access by joint code design across multiple antennas, subcarriers, and users. Such system will benefit from the combined space and frequency domain freedom as well as multiuser diversity. Hence, better spectrum efficiency is achieved while improving bit error rate performance with respect to signal-to-interference ratio © 2012 GIRI.Item A modal logic for the CARE usability properties for multimodal user interfaces(2008) Kamel, Nadjet; Selouani, Sid-Ahmed; Hamam, HabibThis paper proposes the use of model- checking technique to validate Multimodal User Interfaces (MUIs). It introduces a modal logic to express the CARE (Complementarity, Assignation, Redundancy and Equivalent) usability properties for MUIs : the LCARE modal logic. The syntax, the semantics and an axiom system for LCARE are defined. LCARE allows for the specification of the CARE usability properties that a MUI must satisfy. The model-checking technique is used to check whether a CARE property, expressed in LCARE, is satisfied by a MUI. For this purpose the user multimodal interactions are modeled by a transition system and the CARE properties are expressed in LCARE formulae. A satisfiability relation is defined. It checks whether a LCARE formula is satisfied by the transition system modeling the multimodal interactions. LCARE allows for the specification of all the CARE usability properties. An illustration is given for the Matis application (Multimodal Airline Travel Information System) as a case study.Item A model-checking approach for the verification of CARE usability properties for multimodal user interfaces(Praise Worthy Prize S.r.l., 2009-01) Kamel, Nadjet; Selouani, Sid-Ahmed; Hamam, HabibA model-checking-based approach is proposed to verify the CARE (Complementarity, Assignement, Redundancy and Equivalence) usability properties for Multimodal User Interfaces (MUIs). This approach reduces the states explosion problem which is the main inconvenience of the model-checking technique. For this, we propose to decompose the transition system describing the behaviours of the MUI into a set of transition systems, and we decompose the temporal logic formula, that specifies the CARE property, into a set of reachability property formulas. The decomposition is based on disabling a set of modalities in the system. The model-checking process of the CARE property is done through a set of stages. At each stage a reachability formula is checked on a MUI component transition system. The process is aborted if a reachability formula is not satisfied. This approach reduces the complexity of the CARE model-checking process. We illustrate this approach, using the SMV (Symbolic Model Verifier) model-checker, on a MUI of a mobile cell phone case study. © 2009 Praise Worthy Prize S.r.l. - All rights reserved.Item MULTI-STREAM FRONT-END PROCESSING FOR ROBUST DISTRIBUTED SPEECH RECOGNITION(International Society for Computers and Their Applications (ISCA), 2008) Kifaya, Kaoukeb; Nourozian, Atta; Selouani, Sid-Ahmed; Hamam, Habib; Tolba, HeshamItem A new hybrid frame ALOHA and binary splitting algorithm for anti-collision in RFID systems(Institute of Electrical and Electronics Engineers Inc., 2010) Al-Medhwahi, Mohammed; Alkholidi, Abdulsalam; Hamam, HabibCollision is considered as one of the most important issues to be in mind in RFID system designing. Although, there are many algorithms that all of them are aiming - at the end - to decrease collision state numbers or to process such states that help achieve an accurate identification process in an acceptable period of time. In this paper, we intend to propose an algorithm offering balanced performance in general and excellent performance in environments with low or medium tags population. It gives the ability to reduce the number of collisions, in the first stage, and to identify tags that failed to be identified due to the occurred collisions, in the next stage. For illustration, we present simulation showing our algorithm performance against some commonly used algorithms.Item Numerical analysis of stimulated Raman scattering in nonlinear photonic crystal fiber for broad spectral content(Institute of Electrical and Electronics Engineers Inc., 2007) Cherif, Rim; Zghal, Mourad; Hamam, HabibWe numerically analyze the stimulated Raman scattering (SRS) in nonlinear photonic crystal fibers (PCF). Generalized nonlinear Schrodinger equation was used to model the propagation of femtosecond pulses in PCF. We demonstrate that, for a sufficiently broad spectral content, stimulated Raman scattering transfers energy from the higher frequency spectral components to lower frequencies, resulting in a continuous self-frequency shift to longer wavelengths. The obtained results show that PCF can generate relatively strong SRS and that the higher the nonlinearity, the faster the speed of soliton fission, thus the greater the number of solitons produced at the same time. The important role of Raman scattering in the generation of a broad supercontinuum is pointed out. © 2007 IEEE.Item OFDM with parity bit selected block spreading(Institute of Electrical and Electronics Engineers Inc., 2010) Moussa, Sherif; Dahmane, Adel Omar; D'Amours, Claude; Hamam, HabibIn this paper, a new scheme that combines Orthogonal Frequency Division Multiplexing (OFDM) with parity bit selected block spreading is introduced. In this proposed method, the data symbols in each block is used to select the spreading code. Therefore, frequency diversity in the system is increased as well as improving the symbol detection due to the inherent coding in the spreading technique. Simulation results show significant improvement in BER performance for the proposed system compared with conventional OFDM one. © 2009 IEEE.