Publications

2017

• Estimateur de Tyler régularisé dans le cas sous-déterminé. Application à la détection d'objets enfouis
  
  • Hoarau Quentin
  • Breloy Arnaud
  • Ginolhac Guillaume
  • Atto Abdourrahmane
  • Nicolas Jean-Marie
  , 2017. Among the various covariance matrix estimators, the regularised Tyler estimator performs independently from the data distribution and is robust to data outlier corruption. However, the shrinkage parameter value selection depends on the target application and data configuration, and have a direct influence on the estimator performance results. Thus finding a generic rule optimal for every criterion is not straightforward. This paper proposes a new regularistaion parameter selection based on a subspace approach. The performances of this method are investigated both in simulation and application to the adaptive buried objects detection problem.
• A subspace approach for shrinkage parameter selection in undersampled configuration for Regularised Tyler Estimators
  
  • Hoarau Quentin
  • Breloy Arnaud
  • Ginolhac Guillaume
  • Atto Abdourrahmane
  • Nicolas Jean Marie
  , 2017, pp.3291 - 3295. Regularized Tyler Estimator's (RTE) have raised attention over the past years due to their attractive performance over a wide range of noise distributions and their natural robustness to outliers. Developing adaptive methods for the selection of the regularisation parameter α is currently an active topic of research. Indeed, the bias-performance compromise of RTEs highly depends on the considered application. Thus, finding a generic rule that is optimal for every criterion and/or data configurations is not straightforward. This issue is addressed in this paper for undersampled configurations (number of samples lower than the dimension of the data). The paper proposes a new regularisation parameter selection based on a subspace reduction approach. The performance of this method is investigated in terms of estimation accuracy and for adaptive detection purposes, both on simulation and real data. (10.1109/ICASSP.2017.7952765)
  DOI : 10.1109/ICASSP.2017.7952765
• A Semi-Automated Approach for the Co-Refinement of Requirements and Architecture Models
  
  • Barkowski Matthias
  • Schneider Melanie
  • Giese Holger
  • Dyck Johannes
  • Tamzalit Dalila
  • Blouin Dominique
  • Borde Etienne
  • Noppen Joost
  , 2017. Requirements and architecture specifications are strongly related as the second provides a solution to a problem stated by the first. This coupling is typically realized by traceability links and maintaining such links becomes extremely difficult as both requirements and architecture specifications frequently evolve, and in particular when the architecture is refined providing an increasing level of details. In such case, not only the traceability must evolve but the requirements must be refined as well. We present a novel semi-automated approach to evolve non-functional requirements and their traceability links following system's architecture refinement in the context of design space exploration and automated code generation. The approach has been prototyped for AADL models refined with the RAMSES tool and for model transformations implemented as Story Diagrams. (10.1109/REW.2017.52)
  DOI : 10.1109/REW.2017.52
• LISP-Views: Monitoring LISP at Large Scale
  
  • Li Yue
  • Abouseif Akram
  • Iannone Luigi
  • Saucez Damien
  , 2017. The Locator/Identifier Separation Protocol (LISP) separates classical IP addresses into two categories: one for identifying terminals, the other for routing. To associate identifiers and locators LISP needs a specific mechanism, called mapping system. This technology is still at an early stage but two experimental platforms have already been deployed in the Internet: LISP Beta Network and LISP-Lab. However, only the LISP Beta Network is monitored with LISPmon that partially monitors the mapping system once a day. To accompany the growth of LISP, a dynamic and complete monitoring system is required. Therefore, we propose LISP-Views, a dynamic versatile large scale LISP monitoring architecture. LISP-Views allows to automatically conduct comprehensive and objective measurements. After running LISP-Views in the wild for several months and comparing the monitoring results with LISPmon, we confirm that LISP-Views provides more detailed and accurate information. We observe the different behaviours between every network entity within mapping system, and also explore the current LISP performance for further improvements.
• Sur l'extremum d'entropie pour les transformations linéaires
  
  • Rioul Olivier
  , 2017. Comme pour le fameux principe de maximum d’entropie, le principe de minimum d’entropie permet de mesurer le caractère gaussien d’un signal. On présente une nouvelle démonstration très simple de ce principe appliqué aux transformations linéaires, qui s’exprime par une inégalité de puissance entropique initialement due à Shannon et généralisée par Zamir et Feder. Cette démonstration est basée sur un argument de transport optimal qui prend la forme d’un simple changement de variables et permet d’établir facilement la condition d’égalité.
• Minimisation de la puissance émise dans les réseaux ad hoc utilisant l'ARQ hybride de Type-I sur canal de Rice
  
  • Leturc Xavier
  • Le Martret C.
  • Ciblat Philippe
  , 2017.
• Procede de simplification de modele de geometrie
  
  • Legrand Hélène
  • Boubekeur Tamy
  , 2017.
• Identification of a thermal building model by learning the dynamics of the solar flux
  
  • Nabil Tahar
  • Roueff François
  • Jicquel Jean-Marc
  • Girard Alexandre
  , 2017.
• Impact of CPU load on video conferencing quality
  
  • Sorokin Roman
  • Rougier Jean-Louis
  • Ricardo Pastrana-Vidal
  • Nicolas Tranquart
  , 2017, 2017. Video conferencing is a well-established area of communications, which have been studied for decades. Recently this area has received a new impulse due to significantly increased bandwidth of Local and Wide area networks and appearance of low-priced video equipment. At the same time, high quality video images such as Full HD may require significant computational resources for their processing. Video processing for conferencing encompasses all manipulations necessary to get advanced user experience (mixing together several video streams or switch the image to the currently speaking participant) as well as operations caused by the incompatibility of endpoints, e.g. trans-coding in the case when participants use different video codecs. (10.1109/IPTCOMM.2017.8169753)
  DOI : 10.1109/IPTCOMM.2017.8169753
• CAM-Infrastructure: a novel solution for service advertise- ment in Cooperative Intelligent Transportation Systems
  
  • Hammi Badis
  • Labiod Houda
  • Segarra Gérard
  • Servel Alain
  • Monteuuis Jean-Philippe
  Advances in Science, Technology and Engineering Systems Journal, Advances in Science Technology and Engineering Systems Journal (ASTESJ), 2017, 2 (3), pp.1422-1431. Cooperative Intelligent Transportation Systems (C-ITS) are gaining ground and currently are almost part of our everyday life. A C-ITS environment can provide numerous services that soon will become essential to roads’ users. The latter resides in improvement of road safety, entertainment, and commercial services. However, in order to provide such services, the C-ITS environment needs an advertisement and dissemination service for them. Indeed, users have to be aware of the available services in order to request them if needed. Current standards of service announcement show their limits, especially regarding the interoperability between communication profiles. For this reason, in this paper, we describes our new service advertisement solution called CAM-Infrastructure. The latter is compliant with ETSI standards and is deployed in SCOOP@F, a nationwide scale project. (10.25046/aj0203178)
  DOI : 10.25046/aj0203178
• Unsharp Masking Geometry Improves 3D Prints
  
  • Herholz Philipp
  • Koch Sebastian
  • Boubekeur Tamy
  • Alexa Marc
  Computer & Graphics (Proc. Shape Modeling International 2017), 2017, 66, pp.135-142. Mass market digital manufacturing devices are severely limited in accuracy and material, resulting in a significant gap between the appearance of the virtual and the real shape. In imaging as well as rendering of shapes, it is common to enhance features so that they are more apparent. We provide an approach for feature enhancement that directly operates on the geometry of a given shape, with particular focus on improving the visual appearance for 3D printing. The technique is based on unsharp masking, modified to handle arbitrary free-form geometry in a stable, efficient way, without causing large scale deformation. On a series of manufactured shapes we show how features are lost as size of the object decreases, and how our technique can compensate for this. We evaluate this effect in a human subject experiment and find significant preference for modified geometry.
• MuLoG, or How to apply Gaussian denoisers to multi-channel SAR speckle reduction?
  
  • Deledalle Charles-Alban
  • Denis Loïc
  • Tabti Sonia
  • Tupin Florence
  IEEE Transactions on Image Processing, Institute of Electrical and Electronics Engineers, 2017, 26 (9), pp.4389-4403. Speckle reduction is a longstanding topic in synthetic aperture radar (SAR) imaging. Since most current and planned SAR imaging satellites operate in polarimetric, interferometric or tomographic modes, SAR images are multi-channel and speckle reduction techniques must jointly process all channels to recover polarimetric and interferometric information. The distinctive nature of SAR signal (complex-valued, corrupted by multiplicative fluctuations) calls for the development of specialized methods for speckle reduction. Image denoising is a very active topic in image processing with a wide variety of approaches and many denoising algorithms available, almost always designed for additive Gaussian noise suppression. This paper proposes a general scheme, called MuLoG (MUlti-channel LOgarithm with Gaussian denoising), to include such Gaussian denoisers within a multi-channel SAR speckle reduction technique. A new family of speckle reduction algorithms can thus be obtained, benefiting from the ongoing progress in Gaussian denoising, and offering several speckle reduction results often displaying method-specific artifacts that can be dismissed by comparison between results. (10.1109/TIP.2017.2713946)
  DOI : 10.1109/TIP.2017.2713946
• SINR Model for MBSFN Based Mission Critical Communications
  
  • Daher Alaa
  • Coupechoux Marceau
  • Godlewski Philippe
  • Kélif Jean-Marc
  • Ngouat Pierre
  • Minot Pierre
  , 2017, pp.1-5. Multicast/Broadcast Single Frequency Network (MBSFN) is envisioned to be a key technology for business and mission critical communications. The need arises to define simple and efficient dimensioning rules for such networks. The Signal to Interference plus Noise Ratio (SINR) is an important key performance parameter since other metrics such as outage probability and capacity can be deduced from it. In this work, we propose an analytical model to derive an approximate closed-form formula of the SINR in a MBSFN. Our model takes into account Inter-Symbol Interference due to the different propagation delays between the User Equipment (UE) and its serving evolved Nodes-B (eNBs). The comparison with Monte Carlo simulations shows that our approach provides accurate results when shadowing standard deviation is low. When shadowing is highly variable, our model, while less accurate, outperforms the traditional approach based on Fenton-Wilkinson. This phenomenon is due to the fact that several eNBs serve the same UE so that shadowing on every individual link compensate.
• Character and Subword-Based Word Representation for Neural Language Modeling Prediction
  
  • Labeau Matthieu
  • Allauzen Alexandre
  , 2017, pp.1-13. Most of neural language models use different kinds of embeddings for word prediction. While word embeddings can be associated to each word in the vocabulary or derived from characters as well as factored morphological decomposition, these word representations are mainly used to parametrize the input, i.e. the context of prediction. This work investigates the effect of using subword units (character and factored morphological decomposition) to build output representations for neural language modeling. We present a case study on Czech, a morphologically-rich language, experimenting with different input and output representations. When working with the full training vocabulary, despite unstable training, our experiments show that augmenting the output word representations with character-based embeddings can significantly improve the performance of the model. Moreover, reducing the size of the output look-up table, to let the character-based embeddings represent rare words, brings further improvement. (10.18653/v1/W17-4101)
  DOI : 10.18653/v1/W17-4101
• Effects of Magnetic Field on the Phase Change Cells and the Formation of Ice Crystals in Biomaterials: Carrot Case
  
  • Liu Bin
  • Song Jianfei
  • Yao Zhaodn
  • Bennacer Rachid
  Journal of Thermal Science and Engineering Applications, American Society of Mechanical Engineers, 2017, 9 (3). (10.1115/1.4035936)
  DOI : 10.1115/1.4035936
• Exploiting Parallelism in Hierarchical Content Stores for High-speed ICN Routers
  
  • Mansilha Rodrigo
  • Barcellos Marinho
  • Leonardi E.
  • Rossi Dario
  Elsevier Computer Networks, 2017, 125, pp.132-145. Information-centric network (ICN) is a novel architecture identifying data as a first class citizen, and caching as a prominent low-level feature. Yet, efficiently using large storage (e.g., 1 TB) at line rate (e.g., 10 Gbps) is not trivial: in our previous work, we proposed an ICN router design equipped with hierarchical caches, that exploits peculiarities of the ICN traffic arrival process. In this paper, we implement such proposal in the NDN Forwarding Daemon (NFD), and carry on a thorough experimental evaluation of its performance with an emulation methodology on common off the shelf hardware. Our study testifies the interest and feasibility of the approach.
• Le dessein de Laplume
  
  • Rioul Olivier
  • Flandrin Patrick
  , 2017. Cet article vise à faire sortir de l’oubli un travail original de 1948 de l’ingénieur français Jacques Laplume, relatif au calcul de la capacité d’un canal bruité, qui a précédé de peu l’article de Claude E. Shannon, le fondateur de la théorie de l’information. Jacques Laplume travaillait indépendamment et isolément en France; son approche est (contrairement à Shannon) plus physique que mathématique bien qu’exploitant explicitement (comme Shannon) le caractère aléatoire du bruit. Un véritable travail de détective a permis de remonter jusqu’à sa famille pour découvrir une personnalité forte aux multiples talents qui s’inscrit dans une véritable saga familiale.
• Sparse representation of multivariate extremes with applications to anomaly detection
  
  • Goix Nicolas
  • Sabourin Anne
  • Clémençon Stéphan
  Journal of Multivariate Analysis, Elsevier, 2017, 161, pp.12-31. Capturing the dependence structure of multivariate extreme events is a major concern in many fields involving the management of risks stemming from multiple sources, e.g., portfolio monitoring, insurance, environmental risk management and anomaly detection. One convenient (nonparametric) characterization of extreme dependence in the framework of multivariate Extreme Value Theory (EVT) is the angular measure, which provides direct information about the probable “directions” of extremes, i.e., the relative contribution of each feature/coordinate of the largest observations. Modeling the angular measure in high-dimensional problems is a major challenge for the multivariate analysis of rare events. The present paper proposes a novel methodology aiming at exhibiting a particular kind of sparsity within the dependence structure of extremes. This is achieved by estimating the amount of mass spread by the angular measure on representative sets of directions corresponding to specific sub-cones of Rd+. This dimension reduction technique paves the way towards scaling up existing multivariate EVT methods. Beyond a non-asymptotic study providing a theoretical validity framework for our method, we propose as a direct application a first anomaly detection algorithm based on multivariate EVT. This algorithm builds a sparse normal profile of extreme behaviors, to be confronted with new (possibly abnormal) extreme observations. Illustrative experimental results provide strong empirical evidence of the relevance of our approach. (10.1016/j.jmva.2017.06.010)
  DOI : 10.1016/j.jmva.2017.06.010
• Dynamics of ultra small semiconductor lasers
  
  • Sarraute Jean-Maxime
  • Schires Kevin
  • Larochelle Sophie
  • Grillot Frédéric
  , 2017.
• One-to-One Matching of RTT and Path Changes
  
  • Wenqin Shao
  • Rougier Jean-Louis
  • Paris Antoine
  • Devienne Francois
  • Viste Mateusz
  , 2017. Route selection based on performance measurements is an essential task in inter-domain Traffic Engineering. It can benefit from the detection of significant changes in RTT measurements and the understanding on potential causes of change. Among the extensive works on change detection methods and their applications in various domains, few focus on RTT measurements. It is thus unclear which approach works the best on such data.In this paper, we present an evaluation framework for change detection on RTT times series, consisting of: 1) a carefully labelled 34,008-hour RTT dataset as ground truth;2) a scoring method specifically tailored for RTT measurements. Furthermore, we proposed a data transformation that improves the detection performance of existing methods.Path changes are as well attended to. We fix shortcomings of previous works by distinguishing path changes due to routing protocols (IGP and BGP) from those caused by load balancing.Finally, we apply our change detection methods to a large set of measurements from RIPE Atlas. The characteristics of both RTT and path changes are analyzed; the correlation between the two are also illustrated. We identify extremely frequent AS path changes yet with few consequences on RTT, which has not been reported before. (10.23919/ITC.2017.8064356)
  DOI : 10.23919/ITC.2017.8064356
• Méthode de Monte Carlo à dynamique hamiltonienne pour estimation d'un modèle thermique de bâtiment
  
  • Nabil Tahar
  • Moulines Eric
  • Jicquel Jean-Marc
  • Girard Alexandre
  • Lajaunie Christian
  , 2017.
• Formalism to assess and enhance the entropy and reliability of a Loop-PUF
  
  • Danger Jean-Luc
  , 2017.
• Machine-Learning Meets Extreme Value Theory
  
  • Clémençon Stéphan
  , 2017.
• Comparison of the nonlinear frequency division multiplexing and OFDM in experiment
  
  • Gemechu Wasyhun A.
  • Song Mengdi
  • Jaouën Yves
  • Wabnitz Stephano
  • Yousefi Mansoor
  , 2017, pp.paper W.3.C.4.
• An Interactive E-book with an Educational Game for Children with Developmental Disorders: A Pilot User Study
  
  • Pistoljevic Nirvana
  • Hulusic Vedad
  , 2017. Children diagnosed with Autism spectrum disorder (ASD), as one of the most complex neurodevelopmental disabilities, are characterized by different brain and functioning development, distinct interaction with the environment and different learning patterns, language and social skills impairments, and repetitive auto-stimulating restricting behaviors. It has been shown that computer-assisted intervention is much more attention captivating and interesting to children compared with a classic approach to teaching, allowing for faster acquisition of skills. This makes these tools and the technology highly suitable for teaching children with autism basic developmental skills. In addition, interactive electronic books showed positive outcomes for comprehension and information acquisition in children with ASD, while decreasing inappropriate children behavior in the classroom. In this paper a pilot user study on an e-book with an embedded educational game for children with developmental disorders was presented. The results show that the e-book can be efficiently used for teaching children with ASD basic developmental skills and that the learned skills can be efficiently transfered to new media and environments. The framework will provide preschool children with and without disabilities with appropriate educational software, to build up their early cognitive abilities and school readiness skills, and promote incorporating technology as part of the educational and pedagogical process in schools.