Publications

2018

• Attack Tree Construction and Its Application to the Connected Vehicle
  
  • Danger Jean-Luc
  • Karray Khaled
  • Guilley Sylvain
  • Abdelaziz Elaabid M.
  , 2018, pp.175-190. (10.1007/978-3-319-98935-8_9)
  DOI : 10.1007/978-3-319-98935-8_9
• Mathematical models for very high resolution SAR data and their applications
  
  • Deledalle Charles-Alban
  • Denis L.
  • Ferraioli G.
  • Tupin Florence
  , 2018.
• Adaptive Window Strategy for Topic Modeling in Document Streams
  
  • Murena Pierre-Alexandre
  • Al-Ghossein Marie
  • Abdessalem Talel
  • Cornuéjols Antoine
  , 2018.
• Procédé de détection de défaillances et limitations des capteurs à l'aide des communications Car2X
  
  • Monteuuis Jean-Philippe
  • Mafrica Stefano
  • Labiod Houda
  • Servel Alain
  • Zhang Jun
  , 2018.
• 4 Leaf Clover RenderingImproving Monte Carlo Path Tracing with Double hierarchies and collaborative denoising
  
  • Boubekeur Tamy
  , 2018.
• The challenge of cerebral magnetic resonance imaging in neonates: A new method using mathematical morphology for the segmentation of structures including diffuse excessive high signal intensities
  
  • Xu Yongchao
  • Morel Baptiste
  • Dahdouh Sonia
  • Puybareau Élodie
  • Virzì Alessio
  • Urien Hélène
  • Géraud Thierry
  • Adamsbaum Catherine
  • Bloch Isabelle
  Medical Image Analysis, Elsevier, 2018, 48, pp.75-94. Preterm birth is a multifactorial condition associated with increased morbidity and mortality. Diffuse excessive high signal intensity (DEHSI) has been recently described on T2-weighted MR sequences in this population and thought to be associated with neuropathologies. To date, no robust and reproducible method to assess the presence of white matter hyperintensities has been developed, perhaps explaining the current controversy over their prognostic value. The aim of this paper is to propose a new semi-automated framework to detect DEHSI on neonatal brain MR images having a particular pattern due to the physiological lack of complete myelination of the white matter. A novel method for semi-automatic segmentation of neonatal brain structures and DEHSI, based on mathematical morphology and on max-tree representations of the images is thus described. It is a mandatory first step to identify and clinically assess homogeneous cohorts of neonates for DEHSI and/or volume of any other segmented structures. Implemented in a user-friendly interface, the method makes it straightforward to select relevant markers of structures to be segmented, and if needed, apply eventually manual corrections. This method responds to the increasing need for providing medical experts with semi-automatic tools for image analysis, and overcomes the limitations of visual analysis alone, prone to subjectivity and variability. Experimental results demonstrate that the method is accurate, with excellent reproducibility and with very few manual corrections needed. Although the method was intended initially for images acquired at 1.5T, which corresponds to usual clinical practice, preliminary results on images acquired at 3T suggest that the proposed approach can be generalized. (10.1016/j.media.2018.05.003)
  DOI : 10.1016/j.media.2018.05.003
• Attribute‐based broadcast encryption scheme for lightweight devices
  
  • Canard Sébastien
  • Hieu Phan Duong
  • Trinh Viet Cuong
  IET Information Security, Institution of Engineering and Technology, 2018, 12 (1), pp.52-59. (10.1049/iet-ifs.2017.0157)
  DOI : 10.1049/iet-ifs.2017.0157
• Shannon et la théorie de l'information
  
  • Rioul Olivier
  , 2018. Analyse de la publication de C.E. Shannon, &quot;A mathematical Theory of Communication&quot;, The Bell System Technical Journal, Vol. 27, pp. 379–423, 623-656, July, October, 1948 (55 pages)</p> Dans ce texte fondateur de la théorie de l’information, Shannon définit la notion de communication, la fonde sur celle de probabilité, définit le terme bit comme mesure logarithmique de l’information, ainsi que la notion d’entropie informatique (par analogie avec celle de Boltzmann en physique statistique). Il définit aussi mathématiquement la capacité d’un canal de transmission : on peut transmettre l’information de façon fiable tant que le débit ne dépasse pas cette capacité – le bruit présent dans le canal ne limite pas la qualité de la communication, mais uniquement le débit de transmission.</p>
• Complexity of the computation of dominating sets in graphs
  
  • Hudry Olivier
  , 2018.
• Mathématiques à/en portée
  
  • Zayana Karim
  Au fil des maths, APMEP, 2018. Le langage mathématique et le langage musical ont de particulier que les mots, les signes, les symboles, n'y désignent pas seulement des objets : ils les incarnent [1]. Mieux : mathématiques et musique se parlent et se comprennent, au point que leur dialogue fut souvent fructueux : l'étude méthodique du monocorde, attribuée à Pythagore ; la pratique, en amateur, de la guitare par Zorn ; l'usage des probabilités par Xénakis ; l'emploi des transformations géométriques par Bach en sont autant d'exemples. Et si les deux disciplines ont leur grammaire, axiomes et théorèmes dans un cas, solfège et harmonie dans l'autre, elles ne se renouvellent que parce qu'elles savent perpétuellement réinventer et dépasser leurs règles. En voici un aperçu, à la portée du collégien. Par Karim Zayana, inspecteur général, professeur invité à Télécom Paristech.. La portée mathématique du langage musical Quand on lit de la musique, on fait déjà, sans le savoir des mathématiques. Une portée, c'est un axe horizontal-axe des temps, et un axe vertical-axe des notes, lesquelles notes sont indissociablement liées à des fréquences, et donc des nombres. Ajoutons une origine, marquée par la clé qui sert de référence, figure 1. Petit raffinement : l'axe vertical n'est, en vérité, pas gradué linéairement mais logarithmiquement. Quand on franchit un barreau, du DO au RÉ par exemple, on multiplie en fait la fréquence par à peu près 9 8 ⁄. Et quand on passe d'un MI au FA, on la multiplie à peu près par la racine carrée de ce nombre, √ 9 8 ⁄ = 3 2√2 ⁄. Autre fait remarquable : nous venons de décrire ce qui s'apparente à la représentation graphique d'une fonction telle que nous la rencontrons communément aujourd'hui. En cela, la musique avait quelques siècles d'avance sur les mathématiques, qui n'ont adopté ce mode d'explicitation qu'au XVII e siècle. Une portée musicale, nous l'avons dit, c'est un repère. Et la géométrie s'invite dès lors spontanément. On va reconnaître, sur certaines partitions, les effets de transformations du plan : translations et symétries ou association des deux. La translation horizontale traduit un décalage temporel, qu'on retrouve dans l'écriture du canon. La translation verticale est, elle, plus ou moins une transposition, c'est-à-dire que l'on Figure 1 Figure 2
• Experimental investigation of practical unforgeable quantum money
  
  • Bozzio Mathieu
  • Orieux Adeline
  • Trigo Vidarte Luis
  • Zaquine Isabelle
  • Kerenidis Iordanis
  • Diamanti Eleni
  npj Quantum Information, Nature, 2018, 4 (1). Wiesner's unforgeable quantum money scheme is widely celebrated as the first quantum information application. Based on the no-cloning property of quantum mechanics, this scheme allows for the creation of credit cards used in authenticated transactions offering security guarantees impossible to achieve by classical means. However, despite its central role in quantum cryptography, its experimental implementation has remained elusive because of the lack of quantum memories and of practical verification techniques. Here, we experimentally implement a quantum money protocol relying on classical verification that rigorously satises the security condition for unforgeability. Our system exploits polarization encoding of weak coherent states of light and operates under conditions that ensure compatibility with state-of-the-art quantum memories. We derive working regimes for our system using a security analysis taking into account all practical imperfections. Our results constitute a major step towards a real-world realization of this milestone protocol. (10.1038/s41534-018-0058-2)
  DOI : 10.1038/s41534-018-0058-2
• A Generative Model for Non-Intrusive Load Monitoring in Commercial Buildings
  
  • Henriet Simon
  • Şimşekli Umut
  • Fuentes Benoît
  • Richard Gael
  Energy and Buildings, Elsevier, 2018. In the recent years, there has been an increasing academic and industrial interest for analyzing the electrical consumption of commercial buildings. Whilst having similarities with the Non Intrusive Load Monitoring (NILM) tasks for residential buildings, the nature of the signals that are collected from large commercial buildings introduces additional difficulties to the NILM research causing existing NILM approaches to fail. On the other hand, the amount of publicly available datasets collected from commercial buildings is very limited, which makes the NILM research even more challenging for this type of large buildings. In this study, we aim at addressing these issues. We first present an extensive statistical analysis of both commercial and residential measurements from public and private datasets and show important differences. Secondly, we develop an algorithm for generating synthetic current waveforms. We then demonstrate using real measurement and quantitative metrics that both our device model and our simulations are realistic and can be used to evaluate NILM algorithms. Finally, to encourage research on commercial buildings we release a synthesized dataset.
• Blind separation of a large number of sparse sources
  
  • Kervazo C.
  • Bobin Jerome
  • Chenot C.
  Signal Processing, Elsevier, 2018, 150, pp.157-165. Blind Source Separation (BSS) is one of the major tools to analyze multi-spectral data with applications that range from astronomical to biomedical signal processing. Nevertheless, most BSS methods fail when the number of sources becomes large, typically exceeding a few tens. Since the ability to estimate large number of sources is paramount in a very wide range of applications, we introduce a new algorithm, coined block-Generalized Morphological Component Analysis (bGMCA) to specifically tackle sparse BSS problems when large number of sources need to be estimated. Sparse BSS being a challenging nonconvex inverse problem in nature, the role played by the algorithmic strategy is central, especially when many sources have to be estimated. For that purpose, the bGMCA algorithm builds upon block-coordinate descent with intermediate size blocks. Numerical experiments are provided that show the robustness of the bGMCA algorithm when the sources are numerous. Comparisons have been carried out on realistic simulations of spectroscopic data. (10.1016/j.sigpro.2018.04.006)
  DOI : 10.1016/j.sigpro.2018.04.006
• Incidence of paradoxical reactions in patients treated with tocilizumab for rheumatoid arthritis: Data from the French registry REGATE
  
  • Terreaux William
  • Masson Claire
  • Eschard Jean-Paul
  • Bardin Thomas
  • Constantin Arnaud
  • Le Dantec Loïc
  • Marcelli Christian
  • Perdriger Aleth
  • Scotto Di Fazano Claire
  • Wendling Daniel
  • Sibilia Jean
  • Morel Jacques
  • Salmon Jean
  Joint Bone Spine, Elsevier Masson, 2018, 85 (1), pp.53-57. Objectives Assess the frequency of paradoxical reactions encountered in daily practice under tocilizumab, using the REGATE (Registry-RoActemra) registry. The secondary objectives were to determine the type of paradoxical reaction and the consequences of these reactions. Methods The REGATE registry is an independent prospective registry, promoted by the French Society of Rheumatology, consisting of patients treated with tocilizumab for rheumatoid arthritis. The paradoxical reaction was retained if it was a paradoxical precipitation of a condition for which tocilizumab was indicated, if tocilizumab was being used for an alternative indication, and if it appeared after at least one tocilizumab infusion. Results Among the 1491 patients included with at least one follow-up visit (3429 patient-years), a paradoxical reaction occurred in 9 patients (0.60% of patients; 2.62/1000 patient-years). These were 7 de novo pathologies (3 vasculitis, 3 uveitis, 1 lupus) and 2 exacerbations of pre-existing conditions (1 vasculitis, 1 lupus). Permanent discontinuation of tocilizumab was chosen for 5 patients. Conclusions In the REGATE registry, the occurrence of paradoxical reactions in patients treated with tocilizumab was rare. (10.1016/j.jbspin.2017.01.002)
  DOI : 10.1016/j.jbspin.2017.01.002
• Open data in the hotel industry: leveraging forthcoming events for hotel recommendation
  
  • Al-Ghossein Marie
  • Abdessalem Talel
  • Barré Anthony
  Information Technology \& Tourism, 2018.
• Phase evolution of the direct detection noise figure of a nondegenerate fiber phase-sensitive amplifier
  
  • Labidi Tarek
  • Fsaifes Ihsan
  • Xie Weilin
  • Chatterjee Debanuj
  • Goldfarb Fabienne
  • Bretenaker Fabien
  Optics Letters, Optical Society of America - OSA Publishing, 2018, 43 (18), pp.4546. We experimentally investigate the evolution of the direct detection noise figure of a nondegenerate phase-sensitive amplifier based on a nonlinear fiber, as a function of the relative phase between the signal, idler, and pump, all other parameters remaining fixed. The use of a fiber with a high stimulated Brillouin scattering threshold permits us to investigate the full range of phase-sensitive gain and noise figure without pump dithering. Good agreement is found with theory, both for signal only and combined signal and idler direct detections. (10.1364/OL.43.004546)
  DOI : 10.1364/OL.43.004546
• Uniformly Projected RCQD QAM: A Low-Complexity Signal Space Diversity Solution over Fading Channels With or Without Erasures
  
  • Arbi Tarak
  • Geller Benoit
  • Yang Jianxiao
  • Abdel Nour Charbel
  • Rioul Olivier
  IEEE Transactions on Broadcasting, Institute of Electrical and Electronics Engineers, 2018. —Rotated and cyclic Q-delayed (RCQD) M-QAM (Quadrature Amplitude Modulation) provides signal space diversity and thus improves system performance over fading channels. However, previously published RCQD solutions were designed without fully considering the high demodulation complexity which prohibits wider applications. In this paper, a complete solution is proposed to reduce complexity for both the modulator and the demodulator. This solution uses a series of rotation angles α =arctan(1/ √ M) which bring many interesting properties to the RCQD signals. A simplified sphere demapping algorithm is derived for fading channels with and without erasure events. In contrast to the sphere-decoder used for MIMO detection, the radius of the proposed sphere-demapper involves an exact amount of constellation points, thereby ensuring to perform the soft demapping operation successfully. Moreover, when either the in-phase (I) or the quadrature component (Q) is erased, the proposed demapping algorithm performs as well as the full-complexity Max-Log algorithm, with a reduced complexity. Compared to the solution currently used in DVB-T2, the proposed method reduces tremendously the computational complexity while still achieving similar performance over fading channels and even better performance over fading erasure channels. (10.1109/TBC.2018.2811618)
  DOI : 10.1109/TBC.2018.2811618
• Prediction of weakly locally stationary processes by auto-regression
  
  • Roueff François
  • Sanchez-Perez Andres
  ALEA : Latin American Journal of Probability and Mathematical Statistics, Instituto Nacional de Matemática Pura e Aplicada (Rio de Janeiro, Brasil) [2006-....], 2018, 15, pp.1215–1239. In this contribution we introduce weakly locally stationary time series through the local approximation of the non-stationary covariance structure by a stationary one. This allows us to define autoregression coefficients in a non-stationary context, which, in the particular case of a locally stationary Time Varying Autoregressive (TVAR) process, coincide with the generating coefficients. We provide and study an estimator of the time varying autoregression coefficients in a general setting. The proposed estimator of these coefficients enjoys an optimal minimax convergence rate under limited smoothness conditions. In a second step, using a bias reduction technique, we derive a minimax-rate estimator for arbitrarily smooth time-evolving coefficients, which outperforms the previous one for large data sets. In turn, for TVAR processes, the predictor derived from the estimator exhibits an optimal minimax prediction rate. (10.30757/ALEA.v15-45)
  DOI : 10.30757/ALEA.v15-45
• Building a coverage hole-free communication tree
  
  • Vergne Anais
  • Decreusefond Laurent
  • Martins Philippe
  , 2018. Wireless networks are present everywhere but their management can be tricky since their coverage may contain holes even if the network is fully connected. In this paper we propose an algorithm that can build a communication tree between nodes of a wireless network with guarantee that there is no coverage hole in the tree. We use simplicial homology to compute mathematically the coverage, and Prim's algorithm principle to build the communication tree. Some simulation results are given to study the performance of the algorithm and compare different metrics. In the end, we show that our algorithm can be used to create coverage hole-free communication groups with a limited number of hops.
• High-Dimensional Mixture Models For Unsupervised Image Denoising (HDMI)
  
  • Houdard Antoine
  • Bouveyron Charles
  • Delon Julie
  SIAM Journal on Imaging Sciences, Society for Industrial and Applied Mathematics, 2018. This work addresses the problem of patch-based image denoising through the unsupervised learning of a probabilistic high-dimensional mixture models on the noisy patches. The model, named hereafter HDMI, proposes a full modeling of the process that is supposed to have generated the noisy patches. To overcome the potential estimation problems due to the high dimension of the patches, the HDMI model adopts a parsimonious modeling which assumes that the data live in group-specific subspaces of low dimension-alities. This parsimonious modeling allows in turn to get a numerically stable computation of the conditional expectation of the image which is applied for denoising. The use of such a model also permits to rely on model selection tools, such as BIC, to automatically determine the intrinsic dimensions of the subspaces and the variance of the noise. This yields a blind denoising algorithm that demonstrates state-of-the-art performance, both when the noise level is known and unknown.
• Caching Encrypted Content via Stochastic Cache Partitioning
  
  • Araldo Andrea
  • Dan Gyorgy
  • Rossi Dario
  IEEE/ACM Transactions on Networking, IEEE/ACM, 2018, 26 (1), pp.548-561. In-network caching is an appealing solution to cope with the increasing bandwidth demand of video, audio and data transfer over the Internet. Nonetheless, in order to protect consumer privacy and their own business, Content Providers (CPs) increasingly deliver encrypted content, thereby preventing Internet Service Providers (ISPs) from employing traditional caching strategies, which require the knowledge of the objects being transmitted. To overcome this emerging tussle between security and effi- ciency, in this paper we propose an architecture in which the ISP partitions the cache space into slices, assigns each slice to a different CP, and lets the CPs remotely manage their slices. This architecture enables transparent caching of encrypted content, and can be deployed in the very edge of the ISP’s network (i.e., base stations, femtocells), while allowing CPs to maintain exclusive control over their content. We propose an algorithm, called SDCP, for partitioning the cache storage into slices so as to maximize the bandwidth savings provided by the cache. A distinctive feature of our algorithm is that ISPs only need to measure the aggregated miss rates of each CP, but they need not know of the individual objects that are requested. We prove that the SDCP algorithm converges to a partitioning that is close to the optimal, and we bound its optimality gap. We use simulations to evaluate SDCP’s convergence rate under stationary and non-stationary content popularity. Finally, we show that SDCP significantly outperforms traditional reactive caching techniques, considering both CPs with perfect and with imperfect knowledge of their content popularity.
• Pas de probas, pas de chocolat !
  
  • Zayana Karim
  Au fil des maths, APMEP, 2018. Expériences aléatoires, lois discrètes et continues, approximation des unes par les autres, intervalles de confiance, fluctuations d’échantillonnage, tests statistiques, paradoxes probabilistes
• Gaussian Priors for Image denoising
  
  • Delon Julie
  • Houdard Antoine
  , 2018. This chapter is dedicated to the study of Gaussian priors for patch-based image denoising. In the last twelve years, patch priors have been widely used for image restoration. In a Bayesian framework, such priors on patches can be used for instance to estimate a clean patch from its noisy version, via classical estimators such as the conditional expectation or the maximum a posteriori. As we will recall, in the case of Gaussian white noise, simply assuming Gaussian (or Mixture of Gaussians) priors on patches leads to very simple closed-form expressions for some of these estimators. Nevertheless, the convenience of such models should not prevail over their relevance. For this reason, we also discuss how these models represent patches and what kind of information they encode. The end of the chapter focuses on the different ways in which these models can be learned on real data. This stage is particularly challenging because of the curse of dimensionality. Through these different questions, we compare and connect several denoising methods using this framework.
• A contrario comparison of local descriptors for change detection in Very High spatial Resolution (VHR) satellite images of urban areas
  
  • Tupin Florence
  • Liu Gang
  • Gousseau Yann
  IEEE Transactions on Geoscience and Remote Sensing, Institute of Electrical and Electronics Engineers, 2018. Change detection is a key problem for many remote sensing applications. In this paper, we present a novel unsupervised method for change detection between two high resolution remote sensing images possibly acquired by two different sensors. This method is based on keypoints matching, evaluation and grouping, and does not require any image co-registration. It consists of two main steps. First, global and local mapping functions are estimated through keypoints extraction and matching. Secondly, based on these mappings, keypoint matchings are used to detect changes and then grouped to extract regions of changes. Both steps are defined through an {\it a contrario} framework, simplifying the parameter setting and providing a robust pipeline. The proposed approach is evaluated on synthetic and real data from different optic sensors with different resolutions, incidence angles and illumination conditions. (10.1109/TGRS.2018.2888985)
  DOI : 10.1109/TGRS.2018.2888985
• Introduction to the issue on physics and applications of laser dynamics (IS-PALD 2017)
  
  • Grillot F.
  • Sciamanna Marc
  • Chan S.-C.
  Optics Express, Optical Society of America - OSA Publishing, 2018, 26 (16), pp.21375-21378. In this paper, we introduce the Optics Express feature issue of the 7th International Symposium on Physics and Applications of Laser Dynamics (IS-PALD). This issue consists of expanded papers related to oral and poster presentations. Selected papers represent the best of IS-PALD 2017. © 2018 Optical Society of America (10.1364/OE.26.021375)
  DOI : 10.1364/OE.26.021375