Time filter

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Guer, France

Parenthoen M.,Laboratory STICC | Murie F.,SPECULAIRE | Thery F.,SPECULAIRE
Proceedings of the 8th ACM SIGGRAPH Conference on Motion in Games, MIG 2015

The Sea Is Your Mirror is an artistic interactive experience where surface cerebral electromagnetic waves from a participant wearing an EEG sensor headset are depicted in real-time as ocean waves in an animated 3D environment. The aim of this article is to describe the sea wave model used for the sea state animation and how it is connected to the brain computer interface (BCI). The sea state is animated by the groupy choppy wave model that provides nonlinear sea states with wave groups and asymmetric wave shapes. The BCI maps the temporal spectrum of the electroencephalogram onto the elevation spectrum of the sea surface. The resulting setup enables the participant to fly over a dynamic sea state: a metaphor for conscious and unconscious neurofeedback. Copyright is held by the owner/author(s). Source

Stankovic I.,Laboratory STICC | Popovic B.,University of Novi Sad | Focone F.,CNRS LIMSI
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)

This paper describes influence of different types of agent’s behaviour in a social human-virtual agent gesture interaction experiment. The interaction was described to participants as a game with the goal of imitating the agent’s slow upper-body movements, and where new subtle movements can be proposed by both the participant and the agent. As we are interested only in body movements, simple virtual agent was built and displayed at a local exhibition, and we asked visitors one by one to play the game. During the interaction, the agent’s behaviour varied from subject to subject, and we observed their responses. Interesting observations have been drawn from the experiment and it seems that only a small variation in the agent’s behaviour and synchronization can lead to a significantly different feel of the game in the participants. © Springer International Publishing Switzerland 2014. Source

Al Amayreh A.,University of Jordan | Le Masson J.,Laboratory STICC | Helard M.,INSA Rennes | Ouzzif M.,Orange S.A.
IET Communications

Elimination of alien crosstalk in coordinated digital subscriber line systems is investigated in this study. In the upstream, the process of crosstalk elimination may take advantage of available coordination at the receiver side. As the signal received at the coordinated terminals can be corrupted by alien crosstalk, the reception process involves passing the signals received at the coordinated terminals through a spatial whitening operation. As part of the contribution in this study, a method is proposed to obtain the spatial whitening filter coefficients. These coefficients are estimated from the cyclic spectrum of alien crosstalk received at the coordinated system terminals, where transmission at the coordinated system is controlled to allow separating the cyclic spectra of both coordinated system and alien crosstalk signals. This study includes evaluation of the whitening receiver performance taking into account the effects of estimation errors. Theoretical derivations are illustrated by numerical results obtained for VDSL2 application. © The Institution of Engineering and Technology 2014. Source

Salzenstein F.,University of Strasbourg | Boudraa A.O.,CNRS Naval Academy Research Institute | Chonavel T.,Laboratory STICC
Multidimensional Systems and Signal Processing

This work aims at introducing some energy operators linked to Teager-Kaiser energy operator (TKEO) (Kaiser in On a simple algorithm to calculate the energy of a signal, pp 381-384, 1990), its associated higher order versions and expanding them to multi-dimensional signals. These operators are very useful for analysing oscillatory signals with time-varying amplitude and frequency (AM-FM). We first propose a new mathematical expression of these operators using directional derivatives along any n-D vector and Kronecker powers (Proposition 1, Sect. 3). This mathematical formulation allows us to extend to n-D case some properties of the classical TKEO such as tracking of AM envelope and instantaneous frequency of a multi-dimensional AM-FM signal. In addition, we have introduced a new scalar function using the directional derivative along a vector to recover the "sign" of the frequency components. Applications of this model to a local n-D AM-FM signal and the related demodulation errors are presented. To show the effectiveness and the robustness of the new class of operators in term of envelope and frequency tracking, results obtained on synthetic and real data are compared to multi-dimensional energy separation algorithm (Maragos and Bovik in J Opt Soc Am A 12:1867-1876, 1995) and to our previously developed method (Salzenstein and Boudraa in Signal Process 89(4):623-640, 2009). Finally, the performances of these methods are investigated in the presence of an additive noise. © 2012 Springer Science+Business Media, LLC. Source

Rolland A.,CNRS Institute of Electronics and Telecommunications, Rennes | Boriskin A.V.,CNRS Institute of Electronics and Telecommunications, Rennes | Person C.,Laboratory STICC | Quendo C.,Laboratory STICC | And 2 more authors.
IEEE Antennas and Wireless Propagation Letters

A lens-corrected smooth-walled axis-symmetrical dielectric-loaded horn antenna is designed and characterized in Ka-band using the bodies of revolution finite-difference time domain (BoR-FDTD) technique and genetic algorithm. The joint optimization of the horn and dielectric loading profiles enables us to develop a horn with a very good gain performance achieved in a frequency range of about 18%. Compared to earlier results, the bandwidth improvement exceeds a factor two. A lightweight prototype is fabricated in metallized foam. A very good agreement between the numerical and measured data is obtained. © 2012 IEEE. Source

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