xiii safety. For this we have proposed a new hybrid approaches of encryption-compression, which a... more xiii safety. For this we have proposed a new hybrid approaches of encryption-compression, which are based on the DES and the AES encryption algorithms of the dominant coefficients, in a mixed-scale representation, of compression by the multi-scale transformation of Faber-Schauder. The comparison of this approach with other methods of encryption-compression showed its good performance.
International Journal of Pattern Recognition and Artificial Intelligence, 1988
ABSTRACT A new method recognizing and locating partially occluded two-dimensional parts is presen... more ABSTRACT A new method recognizing and locating partially occluded two-dimensional parts is presented. The objects are described by a set of segments derived form the polygonal coding of their contours, and by the geometrical relationships between the segments. Rewriting rules are used to improve the stability of the polygonal coding. The identification process utilizes a robust hypothesis generator, from which the segment research assisted by the spatial relationship is propagated into the scene. The originality of this method relies mainly on the use of structural relationships between the segments to select the robust initialization hypotheses, and the use of structural research to achieve hypothesis propagation. These last two points with the use of a hash-coding technique to improve the location of predicted segments, greatly reduce the combinatories and make the algorithm particularly rapid and effective. This approach is integrated within a vision system of a Flexible Assembly Workcell to accomplish the automatic assembly of partially overlapping parts.
In this paper, we propose a Perceptually Optimized Foveation based Embedded ZeroTree Image Coder ... more In this paper, we propose a Perceptually Optimized Foveation based Embedded ZeroTree Image Coder (POEFIC) that introduces a perceptual weighting to wavelet coefficients prior to control SPIHT encoding algorithm in order to reach a targeted bit rate with a perceptual quality improvement with respect to a given bit rate a fixation point which determines the region of interest ROI. The
Distributed constraint satisfaction problems based on nogoods reasoning (2) seem to be the best a... more Distributed constraint satisfaction problems based on nogoods reasoning (2) seem to be the best approach in terms of theoretical time complexity. However, only few optimization protocols get the most out of valued nogoods's power (16). In this paper, we present a new search algorithm for distributed constraint optimization problems (DCOPs), called Distributed Dynamic Branch & Bound (DisDB&B). Agents assigns their
ABSTRACT In this paper, we propose a new approach using a local version of the region-based activ... more ABSTRACT In this paper, we propose a new approach using a local version of the region-based active contour for object segmentation in images presenting heterogeneity in both the object of interest and the background. The local version was recently developed to deal with heterogeneous appearances by relying on extracting the local instead of global image statistics where the local extracted area is defined by using a disk, sketched at each point along the active contour, with a constant radius size inside and outside the contour. However, the use of a constant radius may prevent the active contour getting more information from its neighborhood and thus being trapped by undesired boundaries. To avoid this error segmentation, the local extracted area using our proposed approach is determined based on using two different radii to extract separately the interior and the exterior local information of the active contour. Using synthetic and real images, our approach shows an improvement in term of computation time and outperforms the conventional methods in noisy images presenting heterogeneity in both the object of interest and the background and using inadequate contour initialization.
Proceedings of the 2nd International ICST Conference on Performance Evaluation Methodologies and Tools, 2007
In this paper, we study the performance of Slotted Aloha under power differentiation schemes. We ... more In this paper, we study the performance of Slotted Aloha under power differentiation schemes. We consider the uplink of a cellular system where m mobiles transmit over a common channel to a base station. In particular we analyze random sets possible transmission powers and further study the role of priorities given either to new arriving packet or to backlogged packets. We consider a general capture model where a mobile transmit successfully a packet if its instantaneous SINR is larger than the threshold. Under this capture model, we study both the cooperative team in which a common goal is jointly optimized as well as the noncooperative game problem in which mobiles try to optimize their own objectives. The performance metrics that we study are the throughput and the expected delay. Further we provide a stability analysis and show that schemes with power differentiation and power control can improve significantly the performance and could eliminate in some cases the bi-stable nature of Slotted Aloha.
2008 IEEE Symposium on Computers and Communications, 2008
In this paper, we consider a multimedia data transmission system over a wireless channel, where p... more In this paper, we consider a multimedia data transmission system over a wireless channel, where packets are queued at the transmitter. Multimedia data transmission over wireless networks often suffers from delay, jitter and packet loss. The main problem to implement a wireless network is the high and variable bit error rate in the radio link (fading, shadowing etc), making it
2007 International Symposium on Computational Intelligence and Intelligent Informatics, 2007
The Asynchronous BackTracklng (ABT) algorithm is a well known algorithm for solving distributed c... more The Asynchronous BackTracklng (ABT) algorithm is a well known algorithm for solving distributed constraint satisfaction problems. However, several work which interest to ABT suppose that each agent owns one single variable. In this paper, we present the compilation formulation for Asynchronous Backtracking with complex local problems, resulting in the ABT-cf algorithm. The ABT-cf algorithm is described in detail and its
Proceedings of the 6th International Conference on Mobile Technology, Application and Systems, Mobility '09, 2009
Current mobile users are often equipped with several network interfaces, which may be of differen... more Current mobile users are often equipped with several network interfaces, which may be of different access technologies. Each access technology has specific characteristics in terms of coverage area and technical characteristics (bandwidth, QoS, etc.) and provides diverse commercial opportunities for the operators. It seems likely that these various technologies have to coexist and, from then, solutions of integration and interoperability
Proceedings of the 2012 6th International ICST Conference on Performance Evaluation Methodologies and Tools, VALUETOOLS 2012, 2012
ABSTRACT We present a game theoretic framework for the dynamical behaviors of a duopoly game in t... more ABSTRACT We present a game theoretic framework for the dynamical behaviors of a duopoly game in telecommunications service providers' context. Competition between two Service Providers (SPs) is assumed to take place in terms of their pricing decisions and the Quality of Service (QoS) they offer. According to the SPs' rationality level, we consider two schemes: 1) Both SPs are rational, and 2) One SP is rational and the second SP is boundedly rational. We describe the competitive interaction and analyze the resulting equilibria. Later, we compute explicitly the steady states of the dynamical system induced by bounded rationality, and establish a necessary and sufficient condition for stability of its Nash equilibria (NEs). We prove that there exists exactly one NE which is fair whereas remaining equilibria are unfair. A special feature is that the stability condition of the Nash equilibrium coincides with the instability condition of the boundary equilibria. Thus the system would never be absorbed by any of the unfair equilibria which solves the equilibrium selection issue ! Moreover, we show that considering the delay case (i.e., assuming a market with memory) increases the stability of the system. Here, the size of the memory could be considered for multi-level rationality, which means that bounded rationality tends to rationality as the memory size increases. We finally show that boundedly rational SPs with delay have a higher chance of reaching the fair Nash equilibrium.
2011 IEEE 23rd International Conference on Tools with Artificial Intelligence, 2011
Asynchronous Backtracking is the standard search procedure for distributed constraint reasoning. ... more Asynchronous Backtracking is the standard search procedure for distributed constraint reasoning. It requires a total ordering on the agents. All polynomial space algorithms proposed so far to improve Asynchronous Backtracking by reordering agents during search only allow a limited amount of reordering. In this paper, we propose Agile-ABT, a search procedure that is able to change the ordering of agents more than previous approaches. This is done via the original notion of termination value, a vector of stamps labelling the new orders exchanged by agents during search. In Agile-ABT, agents can reorder themselves as much as they want as long as the termination value decreases as the search progresses. Our experiments show the good performance of Agile-ABT when compared to other dynamic reordering techniques.
2008 IEEE Symposium on Computers and Communications, 2008
... K. Ibrahimitt, R. EI-Azouzit and EH Bouyakhft t LIA/CERI University of Avignon 339 chemin des... more ... K. Ibrahimitt, R. EI-Azouzit and EH Bouyakhft t LIA/CERI University of Avignon 339 chemin des Meinajaries BP1228, 84911 cedex 9 - Avignon - France Email: {khalil.ibrahimi.rachid.elazouzi}@ univ-avignon.fr +LIMIARF Mohammed V-Agdal University Faculte des sciences, 4 ...
EURASIP Journal on Image and Video Processing, 2009
Motion estimation techniques are widely used in todays video processing systems. The most frequen... more Motion estimation techniques are widely used in todays video processing systems. The most frequently used techniques are the optical flow method and phase correlation method. The vast majority of these algorithms consider noise-free data. Thus, in the case of the image sequences are severely corrupted by additive Gaussian (perhaps non-Gaussian) noises of unknown covariance, the classical techniques will fail to work because they will also estimate the noise spatial correlation. In this paper, we have studied this topic from a viewpoint different from the above to explore the fundamental limits in image motion estimation. Our scheme is based on subpixel motion estimation algorithm using bispectrum in the parametric domain. The motion vector of a moving object is estimated by solving linear equations involving third-order hologram and the matrix containing Dirac delta function. Simulation results are presented and compared to the optical flow and phase correlation algorithms; this approach provides more reliable displacement estimates particularly for complex noisy image sequences. In our simulation, we used the database freely available on the web.
In this work, we propose carrying out tests on the encoding sequence of a video sequence to impro... more In this work, we propose carrying out tests on the encoding sequence of a video sequence to improve data flow and average PSNR. We experiment with the choice of reference images, in the process of video compression, by using only the intra and predicted images extracted from sequences.
This article develops two descriptors global and local for colored images. The first allows to do... more This article develops two descriptors global and local for colored images. The first allows to do image retrieval while the second is applied to object recognition. First we combine color and texture attributes in a unique framework. Our approach is based on the physical properties of light bouncing from a scene. Furthermore, it is claimed that the distribution of Gabor filter outputs can also be provided by a Rayleigh. Filter.Thus, we deduce the Rayleigh-Gaussian framework from the Gabor-Gaussian one. Then we compute a descriptor based on statistical measures performed on Rayleigh-Gaussian features. Secondly, we propose a new detection function for interest points and a new characterization of such points. The detection function extends the Harris Laplace method. Our function extracts features invariant to rotation and scale from color images. We use the second moment as a basis of corner decision. Around each feature point we compute a texture descriptor using the Gabor filter. As an evaluation of this new class of interest points, we have implemented a recognition method of 3D objects by indexing a data base on object views; this method is similar to the Lowe method, except that that SIFT features and descriptors are replaced by the ones proposed in our approach.
This paper presents a method of selective coding of still images using an semi-automatic extracti... more This paper presents a method of selective coding of still images using an semi-automatic extraction of Region of Interest (ROI). To facilitate the extraction of ROI which are characterized by complicated arbritrary shapes, the image is first segmented in regions using photometric clustering of the pixels based on the Competitive Agglomeration method. These regions are dilated to eliminate the small and nonsignificant areas. Extracted ROIs are thereafter coded losslessly using JPEG 2000 algorithm while the rest of image (background BG) is coded with loses. Performances of the approach in terms of ROI extraction effectiveness and compression ratio are compared through its applications to a set of color images containing ROIs of various natures.
The transmission and the transfer of images, in free spaces and on lines, must satisfy two object... more The transmission and the transfer of images, in free spaces and on lines, must satisfy two objectives which are: the reduction of the volume of information to free, the maximum possible, the public networks of communication, and the protection in order to ...
The use of the data-processing networks, for the transmission and the transfer of the data, must ... more The use of the data-processing networks, for the transmission and the transfer of the data, must satisfy two objectives which are: the reduction of the volume of information to free, the maximum possible, the public networks of communication, and the protection in order to guarantee a level of optimum safety. For this we have proposed a new hybrid approach of encryption-compression, which is based on the AES encryption algorithm of the dominant coefficients, in a mixedscale representation, of compression by the Faber-schauder Multi-scale Transform (FMT). The comparison of this approach with other methods of encryption-compression, such as Quadtree-AES and DCT-partialencryption, showed its good performance.
xiii safety. For this we have proposed a new hybrid approaches of encryption-compression, which a... more xiii safety. For this we have proposed a new hybrid approaches of encryption-compression, which are based on the DES and the AES encryption algorithms of the dominant coefficients, in a mixed-scale representation, of compression by the multi-scale transformation of Faber-Schauder. The comparison of this approach with other methods of encryption-compression showed its good performance.
International Journal of Pattern Recognition and Artificial Intelligence, 1988
ABSTRACT A new method recognizing and locating partially occluded two-dimensional parts is presen... more ABSTRACT A new method recognizing and locating partially occluded two-dimensional parts is presented. The objects are described by a set of segments derived form the polygonal coding of their contours, and by the geometrical relationships between the segments. Rewriting rules are used to improve the stability of the polygonal coding. The identification process utilizes a robust hypothesis generator, from which the segment research assisted by the spatial relationship is propagated into the scene. The originality of this method relies mainly on the use of structural relationships between the segments to select the robust initialization hypotheses, and the use of structural research to achieve hypothesis propagation. These last two points with the use of a hash-coding technique to improve the location of predicted segments, greatly reduce the combinatories and make the algorithm particularly rapid and effective. This approach is integrated within a vision system of a Flexible Assembly Workcell to accomplish the automatic assembly of partially overlapping parts.
In this paper, we propose a Perceptually Optimized Foveation based Embedded ZeroTree Image Coder ... more In this paper, we propose a Perceptually Optimized Foveation based Embedded ZeroTree Image Coder (POEFIC) that introduces a perceptual weighting to wavelet coefficients prior to control SPIHT encoding algorithm in order to reach a targeted bit rate with a perceptual quality improvement with respect to a given bit rate a fixation point which determines the region of interest ROI. The
Distributed constraint satisfaction problems based on nogoods reasoning (2) seem to be the best a... more Distributed constraint satisfaction problems based on nogoods reasoning (2) seem to be the best approach in terms of theoretical time complexity. However, only few optimization protocols get the most out of valued nogoods's power (16). In this paper, we present a new search algorithm for distributed constraint optimization problems (DCOPs), called Distributed Dynamic Branch & Bound (DisDB&B). Agents assigns their
ABSTRACT In this paper, we propose a new approach using a local version of the region-based activ... more ABSTRACT In this paper, we propose a new approach using a local version of the region-based active contour for object segmentation in images presenting heterogeneity in both the object of interest and the background. The local version was recently developed to deal with heterogeneous appearances by relying on extracting the local instead of global image statistics where the local extracted area is defined by using a disk, sketched at each point along the active contour, with a constant radius size inside and outside the contour. However, the use of a constant radius may prevent the active contour getting more information from its neighborhood and thus being trapped by undesired boundaries. To avoid this error segmentation, the local extracted area using our proposed approach is determined based on using two different radii to extract separately the interior and the exterior local information of the active contour. Using synthetic and real images, our approach shows an improvement in term of computation time and outperforms the conventional methods in noisy images presenting heterogeneity in both the object of interest and the background and using inadequate contour initialization.
Proceedings of the 2nd International ICST Conference on Performance Evaluation Methodologies and Tools, 2007
In this paper, we study the performance of Slotted Aloha under power differentiation schemes. We ... more In this paper, we study the performance of Slotted Aloha under power differentiation schemes. We consider the uplink of a cellular system where m mobiles transmit over a common channel to a base station. In particular we analyze random sets possible transmission powers and further study the role of priorities given either to new arriving packet or to backlogged packets. We consider a general capture model where a mobile transmit successfully a packet if its instantaneous SINR is larger than the threshold. Under this capture model, we study both the cooperative team in which a common goal is jointly optimized as well as the noncooperative game problem in which mobiles try to optimize their own objectives. The performance metrics that we study are the throughput and the expected delay. Further we provide a stability analysis and show that schemes with power differentiation and power control can improve significantly the performance and could eliminate in some cases the bi-stable nature of Slotted Aloha.
2008 IEEE Symposium on Computers and Communications, 2008
In this paper, we consider a multimedia data transmission system over a wireless channel, where p... more In this paper, we consider a multimedia data transmission system over a wireless channel, where packets are queued at the transmitter. Multimedia data transmission over wireless networks often suffers from delay, jitter and packet loss. The main problem to implement a wireless network is the high and variable bit error rate in the radio link (fading, shadowing etc), making it
2007 International Symposium on Computational Intelligence and Intelligent Informatics, 2007
The Asynchronous BackTracklng (ABT) algorithm is a well known algorithm for solving distributed c... more The Asynchronous BackTracklng (ABT) algorithm is a well known algorithm for solving distributed constraint satisfaction problems. However, several work which interest to ABT suppose that each agent owns one single variable. In this paper, we present the compilation formulation for Asynchronous Backtracking with complex local problems, resulting in the ABT-cf algorithm. The ABT-cf algorithm is described in detail and its
Proceedings of the 6th International Conference on Mobile Technology, Application and Systems, Mobility '09, 2009
Current mobile users are often equipped with several network interfaces, which may be of differen... more Current mobile users are often equipped with several network interfaces, which may be of different access technologies. Each access technology has specific characteristics in terms of coverage area and technical characteristics (bandwidth, QoS, etc.) and provides diverse commercial opportunities for the operators. It seems likely that these various technologies have to coexist and, from then, solutions of integration and interoperability
Proceedings of the 2012 6th International ICST Conference on Performance Evaluation Methodologies and Tools, VALUETOOLS 2012, 2012
ABSTRACT We present a game theoretic framework for the dynamical behaviors of a duopoly game in t... more ABSTRACT We present a game theoretic framework for the dynamical behaviors of a duopoly game in telecommunications service providers' context. Competition between two Service Providers (SPs) is assumed to take place in terms of their pricing decisions and the Quality of Service (QoS) they offer. According to the SPs' rationality level, we consider two schemes: 1) Both SPs are rational, and 2) One SP is rational and the second SP is boundedly rational. We describe the competitive interaction and analyze the resulting equilibria. Later, we compute explicitly the steady states of the dynamical system induced by bounded rationality, and establish a necessary and sufficient condition for stability of its Nash equilibria (NEs). We prove that there exists exactly one NE which is fair whereas remaining equilibria are unfair. A special feature is that the stability condition of the Nash equilibrium coincides with the instability condition of the boundary equilibria. Thus the system would never be absorbed by any of the unfair equilibria which solves the equilibrium selection issue ! Moreover, we show that considering the delay case (i.e., assuming a market with memory) increases the stability of the system. Here, the size of the memory could be considered for multi-level rationality, which means that bounded rationality tends to rationality as the memory size increases. We finally show that boundedly rational SPs with delay have a higher chance of reaching the fair Nash equilibrium.
2011 IEEE 23rd International Conference on Tools with Artificial Intelligence, 2011
Asynchronous Backtracking is the standard search procedure for distributed constraint reasoning. ... more Asynchronous Backtracking is the standard search procedure for distributed constraint reasoning. It requires a total ordering on the agents. All polynomial space algorithms proposed so far to improve Asynchronous Backtracking by reordering agents during search only allow a limited amount of reordering. In this paper, we propose Agile-ABT, a search procedure that is able to change the ordering of agents more than previous approaches. This is done via the original notion of termination value, a vector of stamps labelling the new orders exchanged by agents during search. In Agile-ABT, agents can reorder themselves as much as they want as long as the termination value decreases as the search progresses. Our experiments show the good performance of Agile-ABT when compared to other dynamic reordering techniques.
2008 IEEE Symposium on Computers and Communications, 2008
... K. Ibrahimitt, R. EI-Azouzit and EH Bouyakhft t LIA/CERI University of Avignon 339 chemin des... more ... K. Ibrahimitt, R. EI-Azouzit and EH Bouyakhft t LIA/CERI University of Avignon 339 chemin des Meinajaries BP1228, 84911 cedex 9 - Avignon - France Email: {khalil.ibrahimi.rachid.elazouzi}@ univ-avignon.fr +LIMIARF Mohammed V-Agdal University Faculte des sciences, 4 ...
EURASIP Journal on Image and Video Processing, 2009
Motion estimation techniques are widely used in todays video processing systems. The most frequen... more Motion estimation techniques are widely used in todays video processing systems. The most frequently used techniques are the optical flow method and phase correlation method. The vast majority of these algorithms consider noise-free data. Thus, in the case of the image sequences are severely corrupted by additive Gaussian (perhaps non-Gaussian) noises of unknown covariance, the classical techniques will fail to work because they will also estimate the noise spatial correlation. In this paper, we have studied this topic from a viewpoint different from the above to explore the fundamental limits in image motion estimation. Our scheme is based on subpixel motion estimation algorithm using bispectrum in the parametric domain. The motion vector of a moving object is estimated by solving linear equations involving third-order hologram and the matrix containing Dirac delta function. Simulation results are presented and compared to the optical flow and phase correlation algorithms; this approach provides more reliable displacement estimates particularly for complex noisy image sequences. In our simulation, we used the database freely available on the web.
In this work, we propose carrying out tests on the encoding sequence of a video sequence to impro... more In this work, we propose carrying out tests on the encoding sequence of a video sequence to improve data flow and average PSNR. We experiment with the choice of reference images, in the process of video compression, by using only the intra and predicted images extracted from sequences.
This article develops two descriptors global and local for colored images. The first allows to do... more This article develops two descriptors global and local for colored images. The first allows to do image retrieval while the second is applied to object recognition. First we combine color and texture attributes in a unique framework. Our approach is based on the physical properties of light bouncing from a scene. Furthermore, it is claimed that the distribution of Gabor filter outputs can also be provided by a Rayleigh. Filter.Thus, we deduce the Rayleigh-Gaussian framework from the Gabor-Gaussian one. Then we compute a descriptor based on statistical measures performed on Rayleigh-Gaussian features. Secondly, we propose a new detection function for interest points and a new characterization of such points. The detection function extends the Harris Laplace method. Our function extracts features invariant to rotation and scale from color images. We use the second moment as a basis of corner decision. Around each feature point we compute a texture descriptor using the Gabor filter. As an evaluation of this new class of interest points, we have implemented a recognition method of 3D objects by indexing a data base on object views; this method is similar to the Lowe method, except that that SIFT features and descriptors are replaced by the ones proposed in our approach.
This paper presents a method of selective coding of still images using an semi-automatic extracti... more This paper presents a method of selective coding of still images using an semi-automatic extraction of Region of Interest (ROI). To facilitate the extraction of ROI which are characterized by complicated arbritrary shapes, the image is first segmented in regions using photometric clustering of the pixels based on the Competitive Agglomeration method. These regions are dilated to eliminate the small and nonsignificant areas. Extracted ROIs are thereafter coded losslessly using JPEG 2000 algorithm while the rest of image (background BG) is coded with loses. Performances of the approach in terms of ROI extraction effectiveness and compression ratio are compared through its applications to a set of color images containing ROIs of various natures.
The transmission and the transfer of images, in free spaces and on lines, must satisfy two object... more The transmission and the transfer of images, in free spaces and on lines, must satisfy two objectives which are: the reduction of the volume of information to free, the maximum possible, the public networks of communication, and the protection in order to ...
The use of the data-processing networks, for the transmission and the transfer of the data, must ... more The use of the data-processing networks, for the transmission and the transfer of the data, must satisfy two objectives which are: the reduction of the volume of information to free, the maximum possible, the public networks of communication, and the protection in order to guarantee a level of optimum safety. For this we have proposed a new hybrid approach of encryption-compression, which is based on the AES encryption algorithm of the dominant coefficients, in a mixedscale representation, of compression by the Faber-schauder Multi-scale Transform (FMT). The comparison of this approach with other methods of encryption-compression, such as Quadtree-AES and DCT-partialencryption, showed its good performance.
Uploads
Papers by E. Bouyakhf