Error Probability Bound Considering Beat Noise in 2-D OCDMA Systems

Considering a 2-Dimensional Optical Code Division Multiple Access (2-D OCDMA) system using spreading codes in both time and wavelength domains, we study in this paper the impact on the performance of one of the most predominant performance limitation which is beat noise due to the photo detection. The beat noise impact is correlated with the wellknown OCDMA limitation named Multiple Access Interference (MAI). Our contribution is to assess, through a theoretical analysis, an error probability bound of a system working in incoherent or partially coherent optical regime. Thanks to the theoretical error probability expression we have developed, the specifications and requirements needed to neglect beat noise effect in a 2-D OCDMA system with a conventional receiver are easily obtained. For a targeted Bit Error Rate (BER), and a given number of active users, one can determine from our results, the 2-D code family parameters, the available data rate and the optical source characteristics, required to be free of beat noise impact

Building Space Time Block Codes with set partitioning for three transmit antennas: application to STTC Codes

Publication in the conference proceedings of EUSIPCO, Florence, Italy, 200

Mutations in TUBG1, DYNC1H1, KIF5C and KIF2A cause malformations of cortical development and microcephaly.

International audienceThe genetic causes of malformations of cortical development (MCD) remain largely unknown. Here we report the discovery of multiple pathogenic missense mutations in TUBG1, DYNC1H1 and KIF2A, as well as a single germline mosaic mutation in KIF5C, in subjects with MCD. We found a frequent recurrence of mutations in DYNC1H1, implying that this gene is a major locus for unexplained MCD. We further show that the mutations in KIF5C, KIF2A and DYNC1H1 affect ATP hydrolysis, productive protein folding and microtubule binding, respectively. In addition, we show that suppression of mouse Tubg1 expression in vivo interferes with proper neuronal migration, whereas expression of altered γ-tubulin proteins in Saccharomyces cerevisiae disrupts normal microtubule behavior. Our data reinforce the importance of centrosomal and microtubule-related proteins in cortical development and strongly suggest that microtubule-dependent mitotic and postmitotic processes are major contributors to the pathogenesis of MCD

Reverse-Transcriptase Inhibitors in the Aicardi–Goutières Syndrome

International audienceTo the Editor:The Aicardi–Goutières syndrome is a genetic encephalopathy that is associated with childhood illness and death. The syndrome is hypothesized to be due to misidentification of self-derived nucleic acids as nonself and the subsequent induction of a type I interferon–mediated response that simulates an antiviral reaction.1 Endogenous retroelements, mobile genetic elements that can be transcribed to RNA and then to DNA by reverse transcription, constitute 40% of the human genome and represent a potential source of immunostimulatory nucleic acid in patients with this syndrome.

Note Technique: calcul de la densité de probabilité du SNR équivalent à un relai de type Amplify and Forward sans faire la moindre approximation et obtention des performances

Note Technique: calcul de la densité de probabilité du SNR équivalent à un relai de type Amplify and Forward sans faire la moindre approximation et obtention des performances JP Cances, Xlim, UMR CNRS 7252 Résumé : Dans le cadre de cette note technique nous nous intéressons au calcul rigoureux exact de la densité de probabilité du SNR au niveau du récepteur à la destination lorsque l'on utilise un relais intermédiaire de type AF (Amplify and Forward) dans la liaison. En effet, dans la littérature, on approxime le SNR équivalent en négligeant au dénominateur le terme 1 devant la somme des variables aléatoires Y et Z au dénominateur qui représentent les SNR's équivalents sur la liaison source relais et relais destination. A notre connaissance, les calculs présentés dans cette note technique sont les plus précis existant dans le domaine

Polarisation des codes Note technique (Polar Codes, extrait des travaux de l'EPFL)

Cette note technique a pour objet de montrer comment un algorithme de décodage itératif performant peut s’appliquer sur les codes polaires et elle s’inspire des travaux de R Urbank à l’EPFL

Building Space Time Block Codes with Set Partitioning for Three Transmit Antennas: Application to STTC Codes

This paper introduces new variations about the codes recently introduced by Jafarkhani & al named Super Orthogonal Space Time Trellis Codes (SOSTTC). Using powerful set partitioning rules, these codes are able to combine the coding advantage of STTC's together with the advantage diversity of STBC. This partitioning is based mainly on the determinant criterion introduced first by Tarokh. Jafarkhani proposed, in the case of two transmit antennas, a general framework for the construction of SOSTTC with maximum transmission rate 1. The obtained results are quite outstanding with simple trellises. Recently, he extended his previous results to the case of four transmit antennas with a quasi orthogonal Hadamard based Space Time Block Code. In this paper we propose a new application field of these codes in the difficult context of a three transmit antenna system. The new obtained STTC codes enables to improve significantly the performances of existing STTC codes

Note Technique: Approximation de pdf’s à l’aide de mixtures de lois connues

Le but de cette note technique est de montrer comment une distribution inconnue dont on a déterminé l’histogramme peut être approximée par un mélange de lois de probabilité connues. On utilise pour ce faire un algorithme de maximum de vraisemblance que l’on approxime à l’aide de l’algorithme E.M. (Expectation Maximization). On donne trois exemples pour des mélanges de lois Gaussiennes, de lois Gama et de lois de Nakagami-m