BORGNAT , Pierre

An operational framework is developed for testing stationarity relatively to an observation scale, in both stochastic and deterministic contexts. The proposed method is based on a comparison between global and local time-frequency features. The originality is to make use of a family of stationary surrogates for defining the null hypothesis of...

We study the Vélo'v system, a fully automated bike-sharing system in Lyon, using a temporal network representation. A decomposition of this network is proposed by using nonnegative matrix factorisation (NMF), whose the choice of parameters is discussed. This decomposition enables us to represent the temporal network as a mixture of subnetwork,...

-Le traitement des signaux sur graphe, apparu discrètement il y a un peu plus de 4 ans connaît depuis peu un essor remarquable. Sa formalisation en cours en tant que généralisation du traitement numérique du signal contribue largement à ce succès récent. Les recherches actuelles se concentrent essentiellement sur les signaux sur graphe...

Testing stationarity is an important issue in signal analysis and classification. Recently, time-frequency analysis has been investigated to detect the nonstationarity of a given signal, by constructiing from it a set of surrogate, stationarized signals. Time-frequency features are extracted to test the stationarity. Our paper is a further...

An operational framework is developed for testing stationarity relatively to an observation scale. The proposed method makes use of a family of stationary surrogates for defining the null hypothesis of stationarity. As a further contribution to the field, we demonstrate the strict-sense stationarity of surrogate signals and we exploit this...

We study the problem of parametric modeling of network-structured signals with graph filters. To benefit from the properties of several graph shift operators simultaneously, and to enhance interpretability, we investigate combinations of parallel graph filters with different shift operators. Due to their extra degrees of freedom, these models...

The paper is concerned with the approach developed within the ANR Project StaRAC, and it gives an overview of its main results. The objective was to reconsider the concept of stationarity so as to make it operational, allowing for both an interpretation relatively to an observation scale and the possibility of its testing thanks to the use of...

L'objectif de ce papier consiste à décrire la base d'anomalies créée dans le cadre du projet METROSEC. Cette base contient des traces d'anomalies, légitimes (foules subites,...) et illégitimes (DDoS). Elle permet de calibrer les outils de détection d'anomalies développés dans le projet, et de mesurer leurs performances en termes de faux...

Nous nous intéressons à la détection d'attaques sur le réseau Internet. Nos procédures de détection reposent sur l'utilisation de lois non gaussiennes pour modéliser conjointement les distributions marginales du trafic agrégé à différents niveaux. Nous utilisons ensuite plusieurs distances statistiques pour quantifier une rupture dans cette...