Semiparametric estimation of a two-component mixture model

Suppose that univariate data are drawn from a mixture of two distributions that are equal up to a shift parameter. Such a model is known to be nonidentifiable from a nonparametric viewpoint. However, if we assume that the unknown mixed distribution is symmetric, we obtain the identifiability of this model, which is then defined by four unknown parameters: the mixing proportion, two location parameters and the cumulative distribution function of the symmetric mixed distribution. We propose estimators for these four parameters when no training data is available. Our estimators are shown to be strongly consistent under mild regularity assumptions and their convergence rates are studied. Their finite-sample properties are illustrated by a Monte Carlo study and our method is applied to real data.Comment: Published at http://dx.doi.org/10.1214/009053606000000353 in the Annals of Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical Statistics (http://www.imstat.org

A simple and efficient feedback control strategy for wastewater denitrification

Due to severe mathematical modeling and calibration difficulties open-loop feedforward control is mainly employed today for wastewater denitrification, which is a key ecological issue. In order to improve the resulting poor performances a new model-free control setting and its corresponding "intelligent" controller are introduced. The pitfall of regulating two output variables via a single input variable is overcome by introducing also an open-loop knowledge-based control deduced from the plant behavior. Several convincing computer simulations are presented and discussed.Comment: IFAC 2017 World Congress, Toulouse, Franc

Etude d'une nouvelle approche pour la conception de capteurs et d'actionneurs pour le contrôle des systèmes flexibles

COMPIEGNE-BU (601592101) / SudocSudocFranceF

Fairness issues in a chain of IEEE 802.11 stations

We study a simple general scenario of ad hoc networks based on IEEE 802.11 wireless communications, consisting in a chain of transmitters, each of them being in the carrier sense area of its neighbors. Each transmitter always attempts to send some data frames to one receiver in its transmission area, forming a pair sender-receiver. This scenario includes the three pairs fairness problem, and allows to study some fairness issues of the IEEE 802.11 medium access mechanism. We show by simulation that interesting phenomena appear, depending on the number n of pairs in the chain and of its parity. We also point out a notable asymptotic behavior. We introduce a powerful modeling, by simply considering the probability for a transmitter to send data while its neighbors are waiting. This model leads to a non-linear system of equations, which matches very well the simulations, and which allows to study both small and very large chains. We then analyze the fairness issue in the chain regarding some parameters, as well as the asymptotic behavior. By studying very long chains, we notice good asymptotic fairness of the IEEE 802.11 medium sharing mechanism. As an application, we show how to increase the fairness in a chain of three pairs

Improving fairness between close Wi-Fi access points

International audienc

Distributed PolyTeXML Une nouvelle plateforme de partage d'items didactiques

Les actes peuvent être commandés à l'adresse suivante : http://tice2002.insa-lyon.fr/fr/sommaire.htmlPedagogical document building is something that can not be done overnight, and specially when the destination support is the computer. But, although one main goal of Internet is the share of documents, it is not true with pedagogical documents. Few systems and few norms were, and are, specified, but they are not really used. Why? In searching to answer to this question that we have designed a new kind of system and developped a prototype called “Distributed PolyTeXML”.La création de documents pédagogiques est un travail de longue haleine, et il l'est encore plus lorsque le support de présentation est ´électronique. Or aujourd'hui, `a l'heure d'Internet, o`u le mot d'ordre est l'échange d'informations, le partage de documents pédagogiques n'en est qu'à ses premiers balbutiements. Bien que des systèmes ont été développés, ou sont en cours de développement, bien que des normes de caractérisation d'éléments pédagogiques ont été proposées, ou sont en cours de spécification, leur utilisation reste très confidentielle. Pourquoi ? C'est en voulant répondre à cette question, après une étude de l'existant, que nous avons défini une nouvelle catégorie de système, qui s'est concrétisée par le développement d'un prototype nommé “Distributed PolyTeXML”