Small noise asymptotic of the timing jitter in soliton transmission

We consider the problem of the error in soliton transmission in long-haul optical fibers caused by the spontaneous emission of noise inherent to amplification. We study two types of noises driving the stochastic focusing cubic one dimensional nonlinear Schr\"{o}dinger equation which appears in physics in that context. We focus on the fluctuations of the mass and arrival time or timing jitter. We give the small noise asymptotic of the tails of these two quantities for the two types of noises. We are then able to prove several results from physics among which the Gordon--Haus effect which states that the fluctuation of the arrival time is a much more limiting factor than the fluctuation of the mass. The physical results had been obtained with arguments difficult to fully justify mathematically.Comment: Published in at http://dx.doi.org/10.1214/07-AAP449 the Annals of Applied Probability (http://www.imstat.org/aap/) by the Institute of Mathematical Statistics (http://www.imstat.org

Les leviers de la création de valeur partagée en contexte PME : étude exploratoire dans la région Rhône-Alpes

http://www.strategie-aims.com/events/conferences/24-xxiiieme-conference-de-l-aims/communications/3106-les-leviers-de-la-creation-de-valeur-partagee-en-contexte-pme-etude-exploratoire-dans-la-region-rhone-alpes/downloadInternational audienceLa notion de création de valeur partagée (Porter, Kramer, 2011) invite les entreprises à replacer les démarches de responsabilité sociétale (RSE) a u cœur de leur stratégie, tout en recherchant la compétitivité. Parallèlement, les travaux académiques sur la RSE dans l'univers des PME demeurent marginaux en dépit d'un regain d'intérêt récent (Spence, Perrini, 2009). Ce papier exploratoire propose d'interroger la pertinence de la création de valeur partagée au travers de ses trois leviers : (1) l'intégration à un réseau territorialisé; (2) la remise à plat des produits/services et marchés de l'entreprise et (3) la redéfinition de sa chaîne de valeur dans le contexte des PME. Une enquête par questionnaire a été réalisée dans la région Rhône-Alpes auprès de 488 PME. Les résultats des analyses statistiques montrent que la notion de création de valeur partagée telle que présentée par Porter et Kramer (2011) nécessite des aménagements de manière à mieux refléter les réalités des PME. De nature exploratoire, cette étude invite à approfondir les résultats notamment en termes de renforcement potentiel des différents leviers mobilisés par les PME au travers d'une analyse dynamique, par exemple

Reliable ABC model choice via random forests

Approximate Bayesian computation (ABC) methods provide an elaborate approach to Bayesian inference on complex models, including model choice. Both theoretical arguments and simulation experiments indicate, however, that model posterior probabilities may be poorly evaluated by standard ABC techniques. We propose a novel approach based on a machine learning tool named random forests to conduct selection among the highly complex models covered by ABC algorithms. We thus modify the way Bayesian model selection is both understood and operated, in that we rephrase the inferential goal as a classification problem, first predicting the model that best fits the data with random forests and postponing the approximation of the posterior probability of the predicted MAP for a second stage also relying on random forests. Compared with earlier implementations of ABC model choice, the ABC random forest approach offers several potential improvements: (i) it often has a larger discriminative power among the competing models, (ii) it is more robust against the number and choice of statistics summarizing the data, (iii) the computing effort is drastically reduced (with a gain in computation efficiency of at least fifty), and (iv) it includes an approximation of the posterior probability of the selected model. The call to random forests will undoubtedly extend the range of size of datasets and complexity of models that ABC can handle. We illustrate the power of this novel methodology by analyzing controlled experiments as well as genuine population genetics datasets. The proposed methodologies are implemented in the R package abcrf available on the CRAN.Comment: 39 pages, 15 figures, 6 table

An FPGA Software Defined Radio Platform with a High-Level Synthesis Design Flow

International audienceSoftware defined radio (SDR) opens a new door to future Internet of Things with higher degree of designing flexibility in context of wireless system development. Prototyping a remote implementation of wireless protocols on a hardware over the web requires a highly versatile software radio platform along with laid-back designing tools. To this aim, an FPGA-based SDR scheme has been proposed combining Virtex-6 Perseus 6010 platform capabilities and a design flow based on High-Level Synthesis (HLS) tools. A full IEEE 802.15.4 (ZigBee) physical layer has been implemented on the proposed platform from a C-language dataflow specification. All the results have been analyzed to lead to a fair comparison between different design flows. Although the proposed SDR has some designing issues, it shows a noticeable designing potentiality to flexible prototyping of future wireless systems

Control of the Platinum(II) ligating properties of rigid 1,2-diamines: the case of trans-2,3-diaminonorbornane.

Guided by a simple predictive model, a norbornane-based trans-1,2-diamine was identified as a potential bridging ligand for di-nuclear platinum complex formation; efficient synthesis and product characterization confirmed this hypothesis

A fluorescent reporter system for anaerobic thermophiles

Owing to their inherent capacity to make invisible biological processes visible and quantifiable, fluorescent reporter systems have numerous applications in biotechnology. For classical fluorescent protein systems (i.e., GFP and derivatives), chromophore maturation is O2-dependent, restricting their applications to aerobic organisms. In this work, we pioneered the use of the oxygen-independent system FAST (Fluorescence Activating and absorption Shifting tag) in the thermophilic anaerobe Thermoanaerobacter kivui. We developed a modular cloning system that was used to easily clone a library of FAST expression cassettes in an E. coli—Thermoanaerobacter shuttle plasmid. FAST-mediated fluorescence was then assessed in vivo in T. kivui, and we observed bright green and red fluorescence for cells grown at 55°C. Next, we took advantage of this functional reporter system to characterize a set of homologous and heterologous promoters by quantifying gene expression, expanding the T. kivui genetic toolbox. Low fluorescence at 66°C (Topt for T. kivui) was subsequently investigated at the single-cell level using flow cytometry and attributed to plasmid instability at higher temperatures. Adaptive laboratory evolution circumvented this issue and drastically enhanced fluorescence at 66°C. Whole plasmid sequencing revealed the evolved strain carried functional plasmids truncated at the Gram-positive origin of replication, that could however not be linked to the increased fluorescence displayed by the evolved strain. Collectively, our work demonstrates the applicability of the FAST fluorescent reporter systems to T. kivui, paving the way for further applications in thermophilic anaerobes

Cистемна організація уваги та загальні принципи її корекції як засіб оптимізації учбової та професійної діяльності

У статті викладено результати літературних та експериментальних досліджень, у яких розкриваються основні напрямки, котрі стосуються феномени уваги:механізми її виникнення, типи уваги, функції контролю та управління. Розглянуто ряд методів, котрі можуть бути використані для тренінгів, з метою збільшення об’єму уваги, ступеня її концентрації, швидкості, ступеня зосередження, переключення і розподілу