Publications

2018

• TRISK: A local features extraction framework for texture-plus-depth content matching
  
  • Karpushin Maxim
  • Valenzise Giuseppe
  • Dufaux Frederic
  Image and Vision Computing, Elsevier, 2018, 71, pp.1-16. In this paper we present a new complete detector–descriptor framework for local features extraction from grayscale texture-plus-depth images. It is designed by putting together a locally normalized binary descriptor and the popular AGAST corner detector modified to incorporate the depth map into the keypoint detection process. With these new local features, we target image matching applications when significant out-of-plane rotations and viewpoint position changes are present in the input data. Our approach is designed to perform on RGBD images acquired with low-cost sensors such as Kinect without any complex depth map preprocessing such as denoising or inpainting. We show improved results with respect to several other highly competitive local image features through both a classic local feature evaluation procedure and an illustrative application scenario. Moreover, the proposed method requires low computational effort. (10.1016/j.imavis.2017.11.007)
  DOI : 10.1016/j.imavis.2017.11.007
• Capacity Enhancement of Few-Mode Fiber Transmission Systems Impaired by Mode-Dependent Loss
  
  • Amhoud El-Mehdi
  • Rekaya-Ben Othman Ghaya
  • Jaouën Yves
  Applied Sciences, Multidisciplinary digital publishing institute (MDPI), 2018, 8 (3), pp.326. (10.3390/app8030326)
  DOI : 10.3390/app8030326
• Large scale learning tools to teach C and Linux
  
  • Sharrock Rémi
  • Ella Hamonic
  , 2018.
• Une belle photo est-elle universellement belle ?
  
  • Maître Henri
  , 2018. On discute des façons de verifier les approches objectiviste (de Platon par exemple) ou subjectiviste (de Locke par exemple) de l'esthétique par des techniques modernes : neuro-biologie ou psychologie expérimentale.
• Restarting the accelerated coordinate descent method with a rough strong convexity estimate
  
  • Fercoq Olivier
  • Qu Zheng
  Computational Optimization and Applications, Springer Verlag, 2018. We propose new restarting strategies for the accelerated coordinate descent method. Our main contribution is to show that for a well chosen sequence of restarting times, the restarted method has a nearly geometric rate of convergence. A major feature of the method is that it can take profit of the local quadratic error bound of the objective function without knowing the actual value of the error bound. We also show that under the more restrictive assumption that the objective function is strongly convex, any fixed restart period leads to a geometric rate of convergence. Finally, we illustrate the properties of the algorithm on a regularized logistic regression problem and on a Lasso problem.
• Massive MIMO in 5G networks for intercell interference cancellation and capacity boost
  
  • Tabikh Wassim
  , 2018. The evolution of wireless communication must meet the increasingly high demand in mobile data. It is expected to increase the maximum rates of wireless by a factor of 1000 by 2020. Meanwhile, it is clear that to reach this goal, a combination of different ingredients is necessary. The major limitation of wireless systems is the interference due to frequency reuse. This has been a long-standing impairment in cellular networks of all generations that will be further exacerbated in 5G networks, due to the expected dense cell deployment. The use of orthogonal frequency-division multiplexing (OFDM) in 4G leaded to an interference management by dynamic coordination of resource blocks. However, this allowed only modest gains in rates. A new technique of interference management was born 5 years ago, the interference alignment (IA). the IA permits to have a capacity with equals the half of the capacity of an interference-free system. This technique supposes that each transmitter (TX) knows the channels not only towards its receivers (RX)s, but the channels from all TXs to all receivers RXs. A more recent interference technique that boosts IA is massive multiple input multiple output (MIMO), where TXs use antennas at a very large scale. The idea is motivated by many simplifications, which appear in an asymptotic regime where base stations are endowed with large numbers of antennas. This thesis treats the problem of interference cancellation and capacity maximization in massive MIMO. In this context, the thesis proposes new interference management alternatives for the massive MIMO antenna regime, taking into account also the practical challenges of massive antenna arrays.
• Reliability evaluation of circuits designed in multi- and single-stage versions
  
  • Schvittz R.
  • Pontes M.
  • Meinhardt C.
  • Franco D.
  • Naviner Lirida
  • da Rosa L.
  • Butzen P.
  , 2018, pp.1-4. Nanometer circuits suffer heavily from fabrication, transient and permanent failures. Circuit reliability has to be added to the design space. Probabilistic transfer matrix is an exact method to calculate the reliability of a circuit. Traditionally, logic gates are the basic blocks of this method with a constant reliability for all gates and all possible input vector combination. This paper introduces the importance of considering the transistor arrangement as a pre-processing step and presents an analysis of logic functions designed in single- and multi-stage versions. The results show that single-stage versions present higher reliability when compared to the multi-stage solution. These results confirm the higher robustness induced by more complex arrangements. (10.1109/LASCAS.2018.8399927)
  DOI : 10.1109/LASCAS.2018.8399927
• Graph-based wormhole attack detection in mobile ad hoc networks (MANETs)
  
  • Rmayti Mohammad
  • Begriche Youcef
  • Khatoun Rida
  • Khoukhi Lyes
  • Mammeri A.
  , 2018, pp.1-6.
• Keynote speech
  
  • Msahli Mounira
  , 2018, pp.1-1. (10.1109/MOBISECSERV.2018.8311434)
  DOI : 10.1109/MOBISECSERV.2018.8311434
• Low Frequency RFID system for identification and localization in smart cities - Comparison with UHF RFID
  
  • Gharat Vighnesh
  • Baudoin Genevieve
  • Colin Elizabeth
  • Richard Damien Richard
  International Journal of RF Technologies, IOS Press, 2018, 8 (4), pp.191 - 211. (10.3233/RFT-181781)
  DOI : 10.3233/RFT-181781
• Research report on unified stochastic reverberation modeling
  
  • Badeau Roland
  , 2018. In the field of room acoustics, it is well known that reverberation can be characterized statistically in a particular region of the time-frequency domain (after the mixing time and above Schroeder's frequency). Since the 1950s, various formulas have been established, focusing on particular aspects of reverberation: exponential decay over time, correlations between frequencies, correlations between sensors at each frequency, and time-frequency distribution. In this report, we introduce a new stochastic reverberation model, that permits us to retrieve all these well-known results within a common mathematical framework. To the best of our knowledge, this is the first time that such a unification work is presented. The benefits are multiple: several new formulas generalizing the classical results are established, that jointly characterize the spatial, temporal and spectral properties of late reverberation.
• Misbehaviour detection in vehicular networks
  
  • Gu Pengwenlong
  , 2018. This thesis has been dedicated to addressing the misbehaviour detection problem in vehicular networks. Specifically, we focus on two major issues in PHY layer and application layer respectively: Radio Frequency (RF) Jamming attacks and Sybil attacks. Specifically, we adopted three different machine learning methods including Distance based clustering, Support Vector Machine (SVM) and k-nearest neighbours (kNN) in Sybil nodes detection. Based on variation between benign vehicles and Sybil nodes in their driving patterns, the non-existent virtual nodes can be detected. For RF jamming attacks, we focused on the design of countermeasure for the control channel jamming issue in vehicular networks, which is of vital importance to the safety of I2V communications. We proposed to adopt the cooperative relaying techniques to address the control channel jamming problem in vehicular networks, which is based on the idea that the vehicles outside of the jamming area can serve as relays to help forward the control channel signal to the victim vehicles through other the jamming-free service channels. Thus, we extended the jamming issues in multi-antenna RSU scenarios, where the RSU can serve multiple groups of vehicles simultaneously using the multi-group multicast beamforming technique. As a solution, we propose a two stage anti-jamming scheme, whereby the vehicles who have successfully decoded the signal received in the first stage will be selected as relays to cooperatively serve the victim vehicles in the second stage using the coordinated beamforming techniques over a jamming-free service channel.
• Cognitive Policy Based SON Management Demonstrator
  
  • Daher Tony
  • Jemaa Sana Ben
  • Decreusefond Laurent
  , 2018. —Policy Based SON Management (PBSM) framework has been introduced to manage Self-Organizing Networks (SON) functions in a way that they fulfill all together the operator global goals and provide a unique self-organized network that can be controlled as a whole. This framework mainly translates operator global objectives into policies to be followed by individual SON functions. To cope with the complexity of radio networks due to the impact of radio environment and traffic dynamics , we propose to empower the PBSM with cognition capability. We propose a Cognitive PBSM (CPBSM) that relies on a Reinforcement Learning (RL) algorithm which learns the optimal configuration of SON functions and steers them towards the global operator objectives. The visitor will see how changing the operator objectives leads to a reconfiguration of the SON functions in such a way that the new objectives are fulfilled. The operation of a RL based cognitive management will be illustrated and the exploration/exploitation and scalability dilemmas will be explained.
• Performance evaluation of CQIC and TCP BBR in mobile network
  
  • Zhong Zhenzhe
  • Hamchaoui Isabelle
  • Khatoun Rida
  • Serhrouchni Ahmed
  , 2018, pp.1-5. (10.1109/ICIN.2018.8401585)
  DOI : 10.1109/ICIN.2018.8401585
• Sharp exponential inequalities in survey sampling: conditional Poisson sampling schemes
  
  • Bertail Patrice
  • Clémençon Stéphan
  , 2018. This paper is devoted to establishing exponential bounds for the probabilities of deviation of a sample sum from its expectation, when the variables involved in the summation are obtained by sampling in a finite population according to a rejective scheme, generalizing sampling without replacement, and by using an appropriate normalization. In contrast to Poisson sampling, classical deviation inequalities in the i.i.d. setting do not straightforwardly apply to sample sums related to rejective schemes, due to the inherent dependence structure of the sampled points. We show here how to overcome this difficulty, by combining the formulation of rejective sampling as Poisson sampling conditioned upon the sample size with the Escher transformation. In particular, the Bennett/Bernstein type bounds established highlight the effect of the asymptotic variance σ 2 N of the (properly standardized) sample weighted sum and are shown to be much more accurate than those based on the negative association property shared by the terms involved in the summation. Beyond its interest in itself, such a result for rejective sampling is crucial, insofar as it can be extended to many other sampling schemes, namely those that can be accurately approximated by rejective plans in the sense of the total variation distance .
• Nonnegative Matrix Factorization: a (Semi-) Parametric Statistical View
  
  • Bertail Patrice
  • Clémençon Stéphan
  • Zetlaoui Mélanie
  , 2018.
• Sub-pixellic Methods for Sidelobes Suppression and Strong Targets Extraction in Single Look Complex SAR Images
  
  • Abergel Rémy
  • Denis Loïc
  • Ladjal Saïd
  • Tupin Florence
  IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, IEEE, 2018, 11 (3). SAR images display very high dynamic ranges. Man-made structures (like buildings or power towers) produce echoes that are several orders of magnitude stronger than echoes from diffusing areas (vegetated areas) or from smooth surfaces (e.g., roads). The impulse response of the SAR imaging system is thus clearly visible around the strongest targets: sidelobes spread over several pixels, masking the much weaker echoes from the background. To reduce the sidelobes of the impulse response, images are generally spectrally apodized, trading resolution for a reduction of the sidelobes. This apodization procedure (global or shift-variant) introduces spatial correlations in the speckle-dominated areas which complicates the design of estimation methods. This paper describes strategies to cancel sidelobes around point-like targets while preserving the spatial resolution and the statistics of speckle-dominated areas. An irregular sampling grid is built to compensate the sub-pixel shifts and turn cardinal sines into discrete Diracs. A statistically grounded approach for point-like target extraction is also introduced, thereby providing a decomposition of a single look complex image into two components: a speckle-dominated image and the point-like targets. This decomposition can be exploited to produce images with improved quality (full resolution and suppressed sidelobes) suitable both for visual inspection and further processing (multi-temporal analysis, despeckling, interferometry). (10.1109/JSTARS.2018.2790987)
  DOI : 10.1109/JSTARS.2018.2790987
• Approaches for analyzing security properties of smart objects
  
  • Lugou Florian
  , 2018. As embedded systems become more complex, more connected and more involved in critical tasks, the question of how strict security analysis can be performed during embedded system design needs to be thoroughly addressed. In this thesis, we study how automated formal verification can help embedded system designers in evaluating the impact of hardware and software modifications on the security of the whole system. One of the specificities of embedded system design-which is of particular interest for formal verification-is that the system under design is described as interacting hardware and software components. Formally verifying these systems requires taking both types of components into account. To illustrate this fact, we propose an example of a hardware/software co-design (based on Intel SGX) that provides a secure channel between a peripheral and an application. Formal verification can be performed on this system at different levels: from a high-level view (without describing the implementations) or from a low-level implementation. These two cases differ in terms of how tightly coupled the hardware and software components are. In the first case, we propose a model-based approach-for both the partitioning and software design phases- which enables us to describe software and hardware with high-level models and enables a transformation of these models into a formal specification which can be formally analyzed by the ProVerif tool. In the second case, we consider a software implementation and a more concrete
• Blancheur du résidu pour le débruitage d'image
  
  • Riot Paul
  , 2018. Nous proposons une étude de l’utilisation avancée de l’hypothèse de blancheur du bruit pour améliorer les performances de débruitage. Nous mettons en avant l’intérêt d’évaluer la blancheur du résidu par des mesures de corrélation dans différents cadres applicatifs. Dans un premier temps, nous nous plaçons dans un cadre variationnel et nous montrons qu’un terme de contrainte sur la blancheur du résidu peut remplacer l’attache aux données L2 en améliorant significativement les performances de débruitage. Nous le complétons ensuite par des termes de contrôle de la distribution du résidu au moyen des moments bruts. Dans une seconde partie, nous proposons une alternative au rapport de vraisemblance menant, à la norme L2 dans le cas Gaussien blanc, pour mesurer la dissimilarité entre patchs. La métrique introduite, fondée sur l’autocorrélation de la différence des patchs, se révèle plus performante pour le débruitage et la reconnaissance de patchs similaires. Finalement, les problématiques d’évaluation de qualité sans oracle et de choix local de modèle sont abordées. Encore une fois, la mesure de la blancheur du résidu apporte une information pertinente pour estimer localement la fidélité du débruitage.
• Analysis of preemption costs for the stack cache
  
  • Naji Amine
  • Abbaspour Sahar
  • Brandner Florian
  • Jan Mathieu
  Real-Time Systems, Springer Verlag, 2018. The design of tailored hardware has proven a successful strategy to reduce the timing analysis overhead for (hard) real-time systems. The stack cache is an example of such a design that was shown to provide good average-case performance, while remaining easy to analyze. So far, however, the analysis of the stack cache was limited to individual tasks, ignoring aspects related to multitasking. A major drawback of the original stack cache design is that, due to its simplicity, it cannot hold the data of multiple tasks at the same time. Consequently, the entire cache content needs to be saved and restored when a task is preempted. We propose (a) an analysis exploiting the simplicity of the stack cache to bound the overhead induced by task preemption (b) preemption mechanisms for the stack cache exploiting the previous analysis and, finally, (c) an extension of the design that allows to (partially) hide the overhead by virtualizing stack caches. (10.1007/s11241-018-9298-7)
  DOI : 10.1007/s11241-018-9298-7
• Weblinux: run linux 100% client-side in the browser
  
  • Sharrock Rémi
  , 2018.
• Morphologic for knowledge dynamics: revision, fusion, abduction
  
  • Bloch Isabelle
  • Lang Jérôme
  • Pino Pérez Ramon
  • Uzcategui Carlos
  , 2018. Several tasks in artificial intelligence require to be able to find models about knowledge dynamics. They include belief revision, fusion and belief merging, and abduction. In this paper we exploit the algebraic framework of mathematical morphology in the context of propositional logic, and define operations such as dilation or erosion of a set of formulas. We derive concrete operators, based on a semantic approach, that have an intuitive interpretation and that are formally well behaved, to perform revision, fusion and abduction. Computation and tractability are addressed, and simple examples illustrate the typical results that can be obtained.
• Experimental demonstration of a single- and dual-polarization NFDM in normal dispersion fiber
  
  • Gemechu Wasyhun A.
  • Wabnitz Stephano
  • Song Mengdi
  • Jaouën Yves
  • Yousefi Mansoor
  • Gui Tao
  • Goossens Jen-Willem
  , 2018.
• Temperature dependence of a mid-infrared quantum cascade laser with external optical feedback
  
  • Spitz Olivier
  • Wu Jiagui
  • Khanal Sudeep
  • Carras Mathieu
  • Williams Benjamin S
  • Wong Chee Wei
  • Grillot Frederic
  Proceedings of SPIE, the International Society for Optical Engineering, SPIE, The International Society for Optical Engineering, 2018, 10540, pp.58. Quantum cascade lasers (QCLs) exploit radiative intersubband transitions within the conduction band of semiconductor heterostructures. The wide range of wavelengths achievable with QCLs, from mid-infrared to terahertz range, leads to a large number of applications including absorption spectroscopy, optical countermeasures and free space communications requiring stable single-mode operation with a narrow linewidth, high output power and high modulation bandwidth. Prior work has unveiled the occurrence of temporal chaos in a QCL subjected to optical feedback, with a scenario involving oscillations at the external cavity frequency and low-frequency fluctuations. The purpose of this work is to further investigate the temperature dependence of a mid-infrared QCL with optical feedback. When the semiconductor device is cooled down to 170K, experiments unveil that the laser destabilization appears at a lower feedback ratio and that the chaotic bubble slightly expands owing to a different carrier lifetime dynamics. These results are of paramount importance for new mid-infrared applications such as chaos-encrypted free-space communications or unpredictable countermeasures. (10.1117/12.2290117)
  DOI : 10.1117/12.2290117
• Convergence Speed of a Primal-Dual Coordinate Descent Method
  
  • Fercoq Olivier
  , 2018.