Publications

2017

• A Controlled Matching Game for WLANs
  
  • Touati Mikael
  • El-Azouzi Rachid
  • Coupechoux Marceau
  • Altman Eitan
  • Kelif Jean-Marc
  IEEE Journal on Selected Areas in Communications, Institute of Electrical and Electronics Engineers, 2017, 35, pp.707 - 720. In multi-rate IEEE 802.11 WLANs, the traditional user association based on the strongest received signal and the well known anomaly of the MAC protocol can lead to overloaded Access Points (APs), and poor or heterogeneous performance. Our goal is to propose an alternative game-theoretic approach for association. We model the joint resource allocation and user association as a matching game with complementarities and peer effects consisting of selfish players solely interested in their individual throughputs. Using recent game-theoretic results we first show that various resource sharing protocols actually fall in the scope of the set of stability-inducing resource allocation schemes. The game makes an extensive use of the Nash bargaining and some of its related properties that allow to control the incentives of the players. We show that the proposed mechanism can greatly improve the efficiency of 802.11 with heterogeneous nodes and reduce the negative impact of peer effects such as its MAC anomaly. The mechanism can be implemented as a virtual connectivity management layer to achieve efficient APs-user associations without modification of the MAC layer. (10.1109/JSAC.2017.2672258)
  DOI : 10.1109/JSAC.2017.2672258
• A sharp oracle inequality for Graph-Slope
  
  • Bellec Pierre C.
  • Salmon Joseph
  • Vaiter Samuel
  Electronic Journal of Statistics, Shaker Heights, OH : Institute of Mathematical Statistics, 2017, 11 (2), pp.4851-4870. Following recent success on the analysis of the Slope estimator, we provide a sharp oracle inequality in term of prediction error for Graph-Slope, a generalization of Slope to signals observed over a graph. In addition to improving upon best results obtained so far for the Total Variation denoiser (also referred to as Graph-Lasso or Generalized Lasso), we propose an efficient algorithm to compute Graph-Slope. The proposed algorithm is obtained by applying the forward-backward method to the dual formulation of the Graph-Slope optimization problem. We also provide experiments showing the practical applicability of the method. (10.1214/17-EJS1364)
  DOI : 10.1214/17-EJS1364
• A Landmark Detection Approach Applied to Robust Estimation of the Exposure Index in Digital Radiography
  
  • Irrera Paolo
  • Bloch Isabelle
  • Delplanque Maurice
  Innovation and Research in BioMedical engineering, Elsevier Masson, 2017, 38 (1), pp.42 - 55. Purpose. The exposure index is an important measure used in digital radiography to control the dose at the detector. This value should be computed in regions of interest that are adapted to each patient's anatomy and pose. Material and methods. We propose to define automatically these regions based on anatomical landmarks in the main structures of interest (head, tho-racic spine, lungs, lumbar spine, pelvis, femurs, knees, tibiae). This task is achieved by combining the global information on the size and the positions of the anatomical structures on the one hand, with local analysis on the other hand. Results. Experimental results, on a varied database of 82 full-body acquisitions , demonstrate the interest of the proposed approach, with less errors than existing approaches, in particular on frontal view acquisitions. The method is also robust to variations in patient's conditions and to the potential presence of metallic objects. Conclusion. The approach proposed in this paper allows consistently estimating exposure index values associated with different X-ray acquisitions. This suggests that the application of the proposed method to clinical practice is promising. (10.1016/j.irbm.2016.12.001)
  DOI : 10.1016/j.irbm.2016.12.001
• Reassigned Time-Frequency Representations of Discrete Time Signals and Application to the Constant Q Transform
  
  • Fenet Sébastien
  • Badeau Roland
  • Richard Gael
  Signal Processing, Elsevier, 2017, 132, pp.170-176. In this paper we provide a formal justification of the use of time-frequency reassignment techniques on time-frequency transforms of discrete time signals. State of the art techniques indeed rely on formulae established in the continuous case which are applied, in a somehow inaccurate manner, to discrete time signals. Here, we formally derive a general framework for discrete time reassignment. To illustrate its applicability and generality, this framework is applied to a specific transform: the Constant Q Transform. (10.1016/j.sigpro.2016.10.008)
  DOI : 10.1016/j.sigpro.2016.10.008
• Vidéo-ethnographie des usages de Gallica. Une exploration au plus près de l’activité
  
  • Rollet Nicolas
  • Beaudouin Valérie
  • Garron Isabelle
  Document numérique - Revue des sciences et technologies de l'information. Série Document numérique, Hermès, 2017, 20. Dans l’objectif d’observer au plus près les parcours des utilisateurs et les spécificités de leurs pratiques sur la bibliothèque numérique Gallica, nous avons effectué des captations audiovisuelles des activités à l’écran, complétées par des entretiens d’autoconfrontation qui permettent d’élaborer du sens aux observations. Deux axes d’analyse découlent des données recueillies. Le premier porte sur les phénomènes de catégorisation et d’évaluation (d’une liste de résultats, d’un document) et souligne la façon dont une idée, guidée par des motifs et dynamisée par de la sérendipité, peut émerger et se configurer dans le temps de la consultation. Le second explore la dimension écologique de l’usage de Gallica. Il met en lumière que l’utilisateur de Gallica est engagé dans de nombreuses opérations structurantes associant environnement numérique, matériel et social. (10.3166/dn.2017.00014)
  DOI : 10.3166/dn.2017.00014
• Method, device, and computer program for generating timed media data
  
  • Denoual Franck
  • Mazé Frédéric
  • Le Feuvre J.
  • Ouedraogo Nael
  • Taquet Jonathan
  , 2017.
• A User Perception--Based Approach to Create Smiling Embodied Conversational Agents
  
  • Ochs Magalie
  • Pelachaud Catherine
  • Mckeown Gary
  ACM Transactions on Interactive Intelligent Systems, Association for Computing Machinery (ACM), 2017, 7 (1), pp.4. In order to improve the social capabilities of embodied conversational agents, we propose a computational model to enable agents to automatically select and display appropriate smiling behavior during human-machine interaction. A smile may convey different communicative intentions depending on subtle characteristics of the facial expression and contextual cues. So, to construct such a model, as a first step, we explore the morphological and dynamic characteristics of different types of smile (polite, amused and embarrassed smiles) that an embodied conversational agent may display. The resulting lexicon of smiles is based on a corpus of virtual agent's smiles directly created by users and analyzed through a machine learning technique. Moreover, during an interaction, the expression of smile impacts on the observer's perception of the interpersonal stance of the speaker. As a second step, we propose a probabilistic model to automatically compute the user's potential perception of the embodied conversational agent's social stance depending on its smiling behavior and on its physical appearance. This model, based on a corpus of users' perception of smiling and non-smiling virtual agents, enables a virtual agent to determine the appropriate smiling behavior to adopt given the interpersonal stance it wants to express. An experiment using real human-virtual agent interaction provided some validation of the proposed model. (10.1145/2925993)
  DOI : 10.1145/2925993
• Framework to Relate / Combine Modeling Languages and Techniques
  
  • Al-Ali Rima
  • Amrani Moussa
  • Bandyopadhyay Soumyadip
  • Barisic Ankica
  • Barros Fernando
  • Blouin Dominique
  • Erata Ferhat
  • Giese Holger
  • Iacono Mauro
  • Klikovits Stefan
  • Navarro Eva
  • Pelliccione Patrizio
  • Taveter Kuldar
  • Tekinerdogan Bedir
  • Vanherpen Ken
  , 2017.
• Quantitative analysis of normal and pathologic adrenal glands with 18F-FDOPA PET/CT
  
  • Moreau Aurélie
  • Giraudet Anne
  • Kryza David
  • Borson-Chazot Françoise
  • Bournaud Claire
  • Mognetti Thomas
  • Lifante Jean-Christophe
  • Combemale Patrick
  • Giammarile Francesco
  • Houzard Claire
  Nuclear Medicine Communications, Lippincott, Williams & Wilkins, 2017, 38 (9), pp.771-779. (10.1097/MNM.0000000000000708)
  DOI : 10.1097/MNM.0000000000000708
• Bravo monsieur Le Monde !
  
  • Zayana Karim
  Bulletion de l'APMEP, 2017. Mesurer la circonférence terrestre sans tourner en rond : Ce texte reprend un exposé donné le 10 mars 2017 au lycée Jean Zay à Paris, dans le cadre du plan national de formation « Construction des croisements didactiques en mathématiques et physique-chimie au collège
• Non-Local Patch-Based Image Inpainting
  
  • Newson Alasdair
  • Almansa Andrés
  • Gousseau Yann
  • Pérez Patrick
  Image Processing On Line, IPOL - Image Processing on Line, 2017, 7, pp.373-385. Image inpainting is the process of filling in missing regions in an image in a plausible way. In this contribution, we propose and describe an implementation of a patch-based image inpainting algorithm. The method is actually a two-dimensional version of our video inpainting algorithm proposed in [A. Newson et al., Video inpainting of complex scenes, SIAM Journal of Imaging Sciences, 7 (2014)]. The algorithm attempts to minimize a highly non-convex functional, first introducted by Wexler et al. in [Wexler et al., Space-time video completion, CCVPR (2004)]. The functional specifies that a good solution to the inpainting problem should be an image where each patch is very similar to its nearest neighbor in the unoccluded area. Iterations are performed in a multi-scale framework which yields globally coherent results. In this manner two of the major goals of image inpainting, the correct reconstruction of textures and structures, are addressed. We address a series of important practical issues which arise when using such an approach. In particular, we reduce execution times by using the PatchMatch [C. Barnes, PatchMatch: a randomized correspondence algorithm for structural image editing, ACM Transactions on Graphics, (2009)] algorithm for nearest neighbor searches, and we propose a modified patch distance which improves the comparison of textured patches. We address the crucial issue of initialization and the choice of the number of pyramid levels, two points which are rarely discussed in such approaches. We provide several examples which illustrate the advantages of our algorithm, and compare our results with those of state-of-the-art methods. (10.5201/ipol.2017.189)
  DOI : 10.5201/ipol.2017.189
• How to Find the Best Rated Items on a Likert Scale and How Many Ratings Are Enough
  
  • Liu Qing
  • Basu Debabrota
  • Goel Shruti
  • Abdessalem Talel
  • Bressan Stéphane
  , 2017, pp.351-359. (10.1007/978-3-319-64471-4_28)
  DOI : 10.1007/978-3-319-64471-4_28
• Discovery and Registration: Finding and Integrating Components into Dynamic Systems
  
  • Rodriguez Berha Helena
  • Moissinac Jean-Claude Jc
  , 2017, pp.325-349. One of the major gaps in the current HTML5 web platform is the lack of an interoperable means for a multimodal application to discover services and applications available in a given space and network, for example, in a smart house with a network of connected objects. To address this gap, the Multimodal Interaction Working Group has produced a draft specification based on distributed services, which aims to support the Discovery and Registration of multimodal components. In this approach, the components are described and virtualized in a Resources Manager communicating bidirectionally through dedicated events. To facilitate the fine-grained management of concurrent multimodal interactions, the Resources Manager registers the distributed components and provides to the Interaction Manager the means to control them. In this way, interoperable search, discovery, and selection of heterogeneous and dynamic features on the Web of Things can be performed by multimodal applications producing natural interaction and a semantically rich user experience. (10.1007/978-3-319-42816-1_15)
  DOI : 10.1007/978-3-319-42816-1_15
• Non-interference and local correctness in transactional memory
  
  • Kuznetsov Petr
  • Peri Sathya
  Theor. Comput. Sci., 2017, 688, pp.103-116. (10.1016/j.tcs.2016.06.021)
  DOI : 10.1016/j.tcs.2016.06.021
• Similarity and Contrast on Conceptual Spaces for Pertinent Description Generation
  
  • Sileno Giovanni
  • Bloch Isabelle
  • Atif Jamal
  • Dessalles Jean-Louis
  , 2017, LNAI 10505, pp.262-275. Within the general objective of conceiving a cognitive architecture for image interpretation able to generate outputs relevant to several target user profiles, the paper elaborates on a set of operations that should be provided by a cognitive space to guarantee the generation of relevant descriptions. First, it attempts to define a working definition of contrast operation. Then, revisiting well-known results in cognitive studies, it sketches a definition of similarity based on contrast, distin- guished from the metric defined on the conceptual space.
• The notion of self-aware computing
  
  • Kounev Samuel
  • Lewis Peter
  • Bellman Kirstie
  • Bencomo Nelly
  • Camara Javier
  • Diaconescu Ada
  • Esterle Lukas
  • Geihs Kurt
  • Giese Holger
  • Gotz Sebastian
  • Inverardi Paola
  • Kephart Jeff
  • Zisman Andrea
  , 2017, pp.3-16.
• Brain lesion detection in 3D PET images using max-trees and a new spatial context criterion
  
  • Urien Hélène
  • Buvat Irène
  • Rougon N. F.
  • Soussan Michael
  • Bloch Isabelle
  , 2017, LNCS 10225, pp.455-466. In this work, we propose a new criterion based on spatial context to select relevant nodes in a max-tree representation of an image, dedicated to the detection of 3D brain tumors for \textsuperscript{18}$F$-FDG PET images. This criterion prevents the detected lesions from merging with surrounding physiological radiotracer uptake. A complete detection method based on this criterion is proposed, and was evaluated on five patients with brain metastases and tuberculosis, and quantitatively assessed using the true positive rates and positive predictive values. The experimental results show that the method detects all the lesions in the PET.
• Détection et segmentation de tumeurs cérébrales en imagerie hybride TEP-IRM
  
  • Urien Hélène
  • Buvat Irène
  • Rougon N. F.
  • Soussan Michael
  • Bloch Isabelle
  , 2017, pp.50.
• A Minimax Optimal Algorithm for Crowdsourcing
  
  • Bonald Thomas
  • Combes Richard
  , 2017. We consider the problem of accurately estimating the reliability of workers based on noisy labels they provide, which is a fundamental question in crowdsourcing. We propose a novel lower bound on the minimax estimation error which applies to any estimation procedure. We further propose Triangular Estimation (TE), an algorithm for estimating the reliability of workers. TE has low complexity, may be implemented in a streaming setting when labels are provided by workers in real time, and does not rely on an iterative procedure. We prove that TE is minimax optimal and matches our lower bound. We conclude by assessing the performance of TE and other state-of-the-art algorithms on both synthetic and real-world data.
• A Multilingual System for Cyberbullying Detection: Arabic Content Detection using Machine Learning
  
  • Haidar Batoul
  • Chamoun Maroun
  • Serhrouchni Ahmed
  Advances in Science, Technology and Engineering Systems Journal, Advances in Science Technology and Engineering Systems Journal (ASTESJ), 2017, 2 (6), pp.275-284. (10.25046/aj020634)
  DOI : 10.25046/aj020634
• On the uncontended complexity of anonymous agreement
  
  • Capdevielle Claire
  • Johnen Colette
  • Kuznetsov Petr
  • Milani Alessia
  Distributed Computing, 2017, 30 (6), pp.459-468. (10.1007/s00446-017-0297-z)
  DOI : 10.1007/s00446-017-0297-z
• Rate Allocation in Predictive Video Coding Using a Convex Optimization Framework
  
  • Fiengo Aniello
  • Chierchia Giovanni
  • Cagnazzo Marco
  • Pesquet-Popescu Béatrice
  IEEE Transactions on Image Processing, Institute of Electrical and Electronics Engineers, 2017, 26 (1), pp.479 - 489. Optimal rate allocation is among the most challenging tasks to perform in the context of predictive video coding, because of the dependencies between frames induced by motion compensation. In this paper, using a recursive rate-distortion model that explicitly takes into account these dependencies, we approach the frame-level rate allocation as a convex optimization problem. This technique is integrated into the recent HEVC encoder, and tested on several standard sequences. Experiments indicate that the proposed rate allocation ensures a better performance (in the rate-distortion sense) than the standard HEVC rate control, and with a little loss w.r.t. an optimal exhaustive research which is largely compensated by a much shorter execution time. (10.1109/TIP.2016.2621666)
  DOI : 10.1109/TIP.2016.2621666
• La fabrique des données brutes. Le travail en coulisses de l'open data
  
  • Denis Jérôme
  • Goëta Samuel
  , 2017. Depuis quelques années, les initiatives d’open data se sont multipliées à travers le monde. Présentées jusque dans la presse grand public comme une ressource inexploitée, le « pétrole » sur lequel le monde serait assis, les données publiques sont devenues objet de toutes les attentions et leur ouverture porteuse de toutes les promesses, à la fois terreau d’un renouveau démocratique et moteur d’une innovation distribuée. Comme dans les sciences, qui ont connu un mouvement de focalisation similaire sur les données et leur partage, l’injonction à l’ouverture opère une certaine mise en invisibilité. Le vocabulaire de la « libération », de la « transparence » et plus encore celui de la « donnée brute » efface toute trace des conditions de production des données, des contextes de leurs usages initiaux et pose leur universalité comme une évidence. Ce chapitre explore les coulisses de l’open data afin de retrouver les traces de cette production et d’en comprendre les spécificités. À partir d’une série d’entretiens ethnographiques dans diverses institutions, il décrit la fabrique des données brutes, dont l’ouverture ne se résume jamais à une mise à disponibilité immédiate, évidente et universelle. Il montre que trois aspects sont particulièrement sensibles dans le processus d’ouverture : l’identification, l'extraction et la « brutification » des données. Ces trois séries d’opérations donnent à voir l’épaisseur sociotechnique des données brutes dont la production mêle dimensions organisationnelles, politiques et techniques.
• Trends in Social Network Analysis - Information Propagation, User Behavior Modeling, Forecasting, and Vulnerability Assessment
  
  • Missaoui Rokia
  • Abdessalem Talel
  • Latapy Mathieu
  , 2017, pp.255. <p>The book collects contributions from experts worldwide addressing recent scholarship in social network analysis such as influence spread, link prediction, dynamic network biclustering, and delurking. It covers both new topics and new solutions to known problems. The contributions rely on established methods and techniques in graph theory, machine learning, stochastic modelling, user behavior analysis and natural language processing, just to name a few. This text provides an understanding of using such methods and techniques in order to manage practical problems and situations. Trends in Social Network Analysis: Information Propagation, User Behavior Modelling, Forecasting, and Vulnerability Assessment appeals to students, researchers, and professionals working in the field.</p> <p> </p> (10.1007/978-3-319-53420-6)
  DOI : 10.1007/978-3-319-53420-6
• Foreword to Radio Science for Humanity: URSI-France 2017 Workshop
  
  • Tanzi Tullio
  • Hamelin Joel
  Radio Science Bulletin, Union Radio-Scientifique Internationale (URSI), 2017 (360), pp.60-61.