Publications

2019

• Depth and Depth-Based Classification with R Package ddalpha
  
  • Pokotylo Oleksii
  • Mozharovskyi Pavlo
  • Dyckerhoff Rainer
  Journal of Statistical Software, University of California, Los Angeles, 2019, 91 (5). (10.18637/jss.v091.i05)
  DOI : 10.18637/jss.v091.i05
• Study of short and mid-infrared telecom links performance for different climatic conditions
  
  • Sauvage Chloé
  • Robert Clélia
  • Sorrente Béatrice
  • Grillot Frédéric
  • Erasme Didier
  , 2019, pp.18. This study assesses the performance in term of availability of a FSO (Free Space Optics) link for two wavelengths, belonging to atmospheric windows, the standard telecom wavelength 1.55 µm and the mid-infrared wavelength 4 µm. To do so, we compute the transmission rate under various atmospheric conditions, including fog. Using the atmospheric transmission rate from our radiative transfer software MATISSE, the link budget is derived for a simple direct emission and detection system. The source and detector components characteristics, from commercial data-sheet, are considered to compute the reception noise. An estimate of the Bit Error Rate (BER) of the FSO link for the two wavelengths is presented as a function of visibility. Assuming a bit error correction and the corresponding BER value, it is possible to derive the limit of visibility under which the optical link is cut. A weather visibility database has been collected and compiled for a year to obtain the theoretical availability of the FSO system. As an example the availability at Velizy-Villacoublay (France) weather station throughout the year 2017 is used. In this case the theoretical link availability wins 30 hours of operation in January 2017 with the 4 µm optical wavelength, that shows the benefit of using mid-infrared for FSO when fog occurs. (10.1117/12.2533209)
  DOI : 10.1117/12.2533209
• Kindey Cortex Segmentation in 2D CT with U-Nets Ensemble Aggregation
  
  • Couteaux Vincent
  • Si-Mohamed S.
  • Renard-Penna R.
  • Nempont O.
  • Lefevre T.
  • Popoff A.
  • Pizaine Guillaume
  • Villain N.
  • Bloch Isabelle
  • Behr J.
  • Bellin M.-F.
  • Roy C.
  • Rouvière O.
  • Montagne S.
  • Lassau N.
  • Boussel L.
  Diagnostic and Interventional Imaging, Elsevier, 2019, 100, pp.211-217.
• Distributed Approximate k-Core Decomposition and Min-Max Edge Orientation: Breaking the Diameter Barrier
  
  • Chan T-H Hubert
  • Sozio Mauro
  • Sun Bintao
  , 2019. We design distributed algorithms to compute approximate solutions for several related graph optimization problems. All our algorithms have round complexity being logarithmic in the number of nodes of the underlying graph and in particular independent of the graph diameter. By using a primal-dual approach, we develop a 2(1 +)-approximation algorithm for computing the coreness values of the nodes in the underlying graph, as well as a 2(1 +)-approximation algorithm for the min-max edge orientation problem, where the goal is to orient the edges so as to minimize the maximum weighted in-degree. We provide lower bounds showing that the aforementioned algorithms are tight both in terms of the approximation guarantee and the round complexity. Finally, motivated by the fact that the densest subset problem has an inherent dependency on the diameter of the graph, we study a weaker version that does not suffer from the same limitation. (10.1109/IPDPS.2019.00044)
  DOI : 10.1109/IPDPS.2019.00044
• On the Optimal Input of the Nondispersive Optical Fiber
  
  • Fahs Jihad
  • Tchamkerten Aslan
  • Yousefi Mansoor
  , 2019.
• Information, The Hidden Side of Life
  
  • Gaucherel Cedric
  • Gouyon Pierre-Henri
  • Dessalles Jean-Louis
  , 2019, pp.212. This book explores the unity of life. It proposes that the concept of information is the inner essence of what we today call life. The importance of information for our species is obvious. Human beings are highly dependent on information, constantly exchanging with conspecifics. In a less apparent way, we are the product of genetic and epigenetic information which determines our development in a given environment from a fertilized egg to the adult stage. Even less apparent is that information plays a determining role in ecosystems. This observation may include the prebiotic systems in which life emerged. Our claim is that Nature processes information continuously. This means that even beyond living entities, we can see messages and decoding procedures. Nature can be said to send messages to its own future and then to decode them. Nature “talks” to itself! The systematic organization of messages suggests that, in some respects, we should even speak of the “languages” of Nature.
• The joint weight enumerator of an LCD code and its dual
  
  • Alahmadi Adel
  • Deza Michel
  • Dutour-Sikirić Mathieu
  • Sole Patrick
  Discrete Applied Mathematics, Elsevier, 2019. A binary linear code is called LCD if it intersects its dual trivially. We show that the coefficients of the joint weight enumerator of such a code with its dual satisfy linear constraints, leading to a new linear programming bound on the size of an LCD code of given length and minimum distance. In addition, we show that this polynomial is, in general, an invariant of a matrix group of dimension 4 and order 12. Also, we sketch a Gleason formula for this weight enumerator. (10.1016/j.dam.2018.10.032)
  DOI : 10.1016/j.dam.2018.10.032
• Trace codes over Z 4 , and Boolean functions
  
  • Shi Minjia
  • Liu Yan
  • Randriambololona Hugues
  • Sok Lin
  • Sole Patrick
  Designs, Codes and Cryptography, Springer Verlag, 2019, 87, pp.1447 - 1455. We construct trace codes over Z 4 based on Boolean functions and their support. The Lee weight distribution of these codes is studied by using the Walsh-Hadamard transform of the Boolean functions, and exponential character sums. We obtain few weights codes. In particular, bent and semi-bent functions give three-weight codes. (10.1007/s10623-018-0542-x)
  DOI : 10.1007/s10623-018-0542-x
• Les Versions de Bases de Données
  
  • Abdessalem Talel
  • Bauzer-Medeiros Claudia
  • Cellary Wojtech
  • Manouvrier Maud
  • Rukoz Marta
  • Zamfiroiu Michel
  , 2019, pp.44-48. In 1990, W. Cellary and G. Jomier proposed the Database Version (DBV) approach, which allows to manage multiversion databases - those in which several versions of a set of data items coexist. Ever since, its model, theory and algorithms have been adopted in a multitude of research initiatives and publications, and have been applied to a variety of applications, in particular those in which there is a need for keeping track of parallel or (spatio)-temporal evolution of states of the world. This article presents an overview of the DBV approach, and some of the associated research initiatives throughout three decades, pointing out new potential directions. It has been written in tribute to Geneviève Jomier, Prof. Emeritus of The Université Paris-Dauphine, who left us in March 2018.
• Fast computation of Tukey trimmed regions and median in dimension p > 2
  
  • Liu Xiaohui
  • Mosler Karl
  • Mozharovskyi Pavlo
  Journal of Computational and Graphical Statistics, Taylor & Francis, 2019. (10.1080/10618600.2018.1546595)
  DOI : 10.1080/10618600.2018.1546595
• Early Detection of User Engagement Breakdown in Spontaneous Human-Humanoid Interaction
  
  • Ben Youssef Atef
  • Clavel Chloé
  • Essid Slim
  IEEE Transactions on Affective Computing, Institute of Electrical and Electronics Engineers, 2019. This paper presents a supervised classification system for forecasting a potential user engagement breakdown in human-robot interaction. We define engagement breakdown as a failure to successfully complete a predefined interaction scenario, where the user leaves before the expected end. The goal is thus to detect as early as possible such a potential engagement breakdown during the interaction between a human and a humanoid robot. To this end, we exploit a dataset that we have collected in real-world conditions where a set of participants were left to spontaneously engage in an interaction with the robot. The dataset is labeled according to the presence/absence of engagement breakdown. This study investigates the use of a multimodal approach to this problem, where a set of non-verbal features is considered to characterize the users' behavior. The use of combined multimodal features is found to effectively improve the performance of the system. The optimal set of data streams useful for this task is the combination of the distance to the robot, gaze and head motion, as well as facial expressions and speech. We study the time extent over which a user's departure can be anticipated. We find that this ability to anticipate the departure depends on the window during which we observe the user behavior.
• On approximating mathematical morphology operators via deep learning techniques
  
  • Velasco-Forero Santiago
  • Ponchon Bastien
  • Blusseau Samy
  • Angulo Jesus
  • Bloch Isabelle
  , 2019, pp.51. Mathematical Morphology (MM) is a well-established discipline whose aim is mainly to provide tools to characterise complex object via their shape/size features. This study addresses the problem of robust approximation of mathematical morphology (MM) operators by deep learning methods. We present two cases, (a) Asymmetric autoencoders for part-based approximations of classical MM in the sense of [1] and, (b) image-to-image translation networks [2] to produce robust MM operators in presence of noise.
• Game Theory for Networks: 8th International EAI Conference, GameNets 2019, Proceedings
  
  • Avrachenkov Konstantin
  • Huang Longbo
  • Marden Jason R.
  • Coupechoux Marceau
  • Giovanidis Anastasios
  , 2019. This book constitutes the refereed proceedings of the 8th EAI International Conference on Game Theory for Networks, GameNets 2019, held in Paris, France, in April 2019. The 8 full and 3 short papers presented were carefully reviewed and selected from 17 submissions. They are organized in the following topical sections: Game Theory for Wireless Networks; Games for Economy and Resource Allocation; and Game Theory for Social Networks. (10.1007/978-3-030-16989-3)
  DOI : 10.1007/978-3-030-16989-3
• Systematic Literature Review on Multi-Paradigm Modelling for Cyber-Physical Systems
  
  • Barisic Ankica
  • Savić Dušan
  • Al-Ali Rima
  • Ruchkin Ivan
  • Blouin Dominique
  • Cicchetti Antonio
  • Eslampanah Raheleh
  • Nikiforova Oksana
  • Abshir Mustafa
  • Challenger Moharram
  • Gomes Claudio
  • Erata Ferhat
  • Tekinerdogan Bedir
  • Amaral Vasco
  • Goulao Miguel
  , 2019.
• Distributed Coordinated Transmission with Forward-Backward Training for 5G Radio Access
  
  • Tolli Antti
  • Ghauch Hadi
  • Kaleva Jarkko
  • Komulainen Petri
  • Bengtsson Mats
  • Skoglund Mikael
  • Honig Michael
  • Lahetkangas Eeva
  • Tiirola Esa
  • Pajukoski Kari
  IEEE Communications Magazine, Institute of Electrical and Electronics Engineers, 2019, 57 (1), pp.58-64. (10.1109/MCOM.2018.1700199)
  DOI : 10.1109/MCOM.2018.1700199
• On Plateaued Functions, Linear Structures, and Permutation Polynomials
  
  • Mesnager Sihem
  • Kaytannci K.
  • Ozbudak Ferruh
  , 2019.
• Knowledge Harvesting: Achievements and Challenges
  
  • Weikum Gerhard
  • Hoffart Johannes
  • Suchanek Fabian
  , 2019. This article gives an overview on knowledge harvesting: automatically constructing large high-quality knowledge bases from Internet sources. The first part reviews key principles and best-practice methods. The second part points out open challenges for future research. (10.1007/978-3-319-91908-9_13)
  DOI : 10.1007/978-3-319-91908-9_13
• Medical imaging and AI
  
  • Bloch Isabelle
  , 2019.
• Tree Sampling Divergence: An Information-Theoretic Metric for Hierarchical Graph Clustering
  
  • Charpentier Bertrand
  • Bonald Thomas
  , 2019. We introduce the tree sampling divergence (TSD), an information-theoretic metric for assessing the quality of the hierarchical clustering of a graph. Any hierarchical clustering of a graph can be represented as a tree whose nodes correspond to clusters of the graph. The TSD is the Kullback-Leibler divergence between two probability distributions over the nodes of this tree: those induced respectively by sampling at random edges and node pairs of the graph. A fundamental property of the proposed metric is that it is interpretable in terms of graph reconstruction. Specifically, it quantifies the ability to reconstruct the graph from the tree in terms of information loss. In particular, the TSD is maximum when perfect reconstruction is feasible , i.e., when the graph has a complete hierarchical structure. Another key property of TSD is that it applies to any tree, not necessarily binary. In particular , the TSD can be used to compress a binary tree while minimizing the information loss in terms of graph reconstruction, so as to get a compact representation of the hierarchical structure of a graph. We illustrate the behavior of TSD compared to existing metrics on experiments based on both synthetic and real datasets.
• Documenting Supermarkets: Contemporary Efforts To Support Intellectually Disturbing Organizations Food Coop (2016) -Tom Boothe Unplugged -Voices
  
  • Ouahab Alban
  M@n@gement, AIMS (Association internationale de management stratégique), 2019, 22, pp.671 - 702.
• Anytime Large-Scale Analytics of Linked Open Data
  
  • Soulet Arnaud
  • Suchanek Fabian
  , 2019. Analytical queries are queries with numerical aggregators: computing the average number of objects per property, identifying the most frequent subjects, etc. Such queries are essential to monitor the quality and the content of the Linked Open Data (LOD) cloud. Many analytical queries cannot be executed directly on the SPARQL endpoints, because the fair use policy cuts off expensive queries. In this paper, we show how to rewrite such queries into a set of queries that each satisfy the fair use policy. We then show how to execute these queries in such a way that the result provably converges to the exact query answer. Our algorithm is an anytime algorithm, meaning that it can give intermediate approximate results at any time point. Our experiments show that the approach converges rapidly towards the exact solution, and that it can compute even complex indicators at the scale of the LOD cloud.
• On-the-fly Detection of User Engagement Decrease in Spontaneous Human-Robot Interaction
  
  • Ben Youssef Atef
  • Varni Giovanna
  • Essid Slim
  • Clavel Chloé
  International Journal of Social Robotics, 2019. In this paper, we address the detection of engagement decrease of users spontaneously interacting with a socially assistive robot in a public space. We first describe the UE-HRI dataset that collects spontaneous Human-Robot Interactions following the guidelines provided by the Affective Computing research community to collect data "in-the-wild". We then analyze the users' behaviors focusing on proxemics, gaze, head motion, facial expressions and speech during interactions with the robot. Engaged behaviors versus signs of engagement decrease exhibited by the users were annotated and analyzed. Finally, we investigate the use of deep leaning techniques (Recurrent and Deep Neural Networks) to detect user engagement decrease in real-time. The results of this work particularly highlight the relevance of taking into account temporal dynamics of the user's behavior. Allowing 1 to 2 seconds as buffer delay improves the performance of taking a decision on user engagement.
• On the Capacity of MIMO Optical Wireless Channels
  
  • Li Longguang
  • Moser Stefan M
  • Wang Ligong
  • Wigger Michèle
  IEEE Transactions on Information Theory, Institute of Electrical and Electronics Engineers, 2019. This paper studies the capacity of a general multiple-input multiple-output (MIMO) free-space optical intensity channel under a per-input-antenna peak-power constraint and a total average-power constraint over all input antennas. The main focus is on the scenario with more transmit than receive antennas. In this scenario, different input vectors can yield identical distributions at the output, when they result in the same image vector under multiplication by the channel matrix. We first determine the most energy-efficient input vectors that attain each of these image vectors. Based on this, we derive an equivalent capacity expression in terms of the image vector, and establish new lower and upper bounds on the capacity of this channel. The bounds match when the signal-to-noise ratio (SNR) tends to infinity, establishing the high-SNR asymptotic capacity. We also characterize the low-SNR slope of the capacity of this channel. (10.1109/ITW.2018.8613496)
  DOI : 10.1109/ITW.2018.8613496
• Merit-guided dynamic feature selection filter for data streams
  
  • Barddal Jean Paul
  • Enembreck Fabrício
  • Gomes Heitor Murilo
  • Bifet Albert
  • Pfahringer Bernhard
  Expert Syst. Appl., 2019, 116, pp.227-242. (10.1016/j.eswa.2018.09.031)
  DOI : 10.1016/j.eswa.2018.09.031
• A 3D Beamforming Scheme Based on The Spatial Distribution of User Locations
  
  • Rachad Jalal
  • Nasri Ridha
  • Decreusefond Laurent
  , 2019. Multi-antenna technologies such as massive Multiple-Input Multiple-Output (massive MIMO) and beamforming are key features to enhance performance, in terms of capacity and coverage, by using a large number of antennas intelligently. With the upcoming 5G New Radio (NR), FD-MIMO (Full Dimension MIMO) will play a major key role. FD-MIMO consists in arranging a large number of antennas in a 2D array, which enables to use 3D beamforming i.e., beamforming in both horizontal and vertical dimensions. The present paper provides a 3D beamforming model where beam steering depends on the random spatial distribution of users. We attempt to derive some analytical results regarding the probability distribution of antenna beamforming radiation pattern. Also, through system level simulations, we show how 3D beamforming can reduce interference impact, compared to the traditional 2D beamforming, and enhances system performance in terms of the coverage probability and users throughput.