Contact patterns among high school students

Face-to-face contacts between individuals contribute to shape social networks and play an important role in determining how infectious diseases can spread within a population. It is thus important to obtain accurate and reliable descriptions of human contact patterns occurring in various day-to-day life contexts. Recent technological advances and the development of wearable sensors able to sense proximity patterns have made it possible to gather data giving access to time-varying contact networks of individuals in specific environments. Here we present and analyze two such data sets describing with high temporal resolution the contact patterns of students in a high school. We define contact matrices describing the contact patterns between students of different classes and show the importance of the class structure. We take advantage of the fact that the two data sets were collected in the same setting during several days in two successive years to perform a longitudinal analysis on two very different timescales. We show the high stability of the contact patterns across days and across years: the statistical distributions of numbers and durations of contacts are the same in different periods, and we observe a very high similarity of the contact matrices measured in different days or different years. The rate of change of the contacts of each individual from one day to the next is also similar in different years. We discuss the interest of the present analysis and data sets for various fields, including in social sciences in order to better understand and model human behavior and interactions in different contexts, and in epidemiology in order to inform models describing the spread of infectious diseases and design targeted containment strategies.Comment: Supplementary Information at http://s3-eu-west-1.amazonaws.com/files.figshare.com/1677807/File_S1.pd

Crypto-Verifying Protocol Implementations in ML

We intend to narrow the gap between concrete implementations and verified models of cryptographic protocols. We consider protocols implemented in F#, a variant of ML, and verified using CryptoVerif, Blanchet's protocol verifier for computational cryptography. We experiment with compilers from F# code to CryptoVerif processes, and from CryptoVerif declarations to F# code. We present two case studies: an implementation of the Otway-Rees protocol, and an implementation of a simplified password-based authentication protocol. In both cases, we obtain concrete security guarantees for a computational model closely related to executable code

Estimating the epidemic risk using non-uniformly sampled contact data

Many datasets describing contacts in a population suffer from incompleteness due to population sampling and underreporting of contacts. Data-driven simulations of spreading processes using such incomplete data lead to an underestimation of the epidemic risk, and it is therefore important to devise methods to correct this bias. We focus here on a non-uniform sampling of the contacts between individuals, aimed at mimicking the results of diaries or surveys, and consider as case studies two datasets collected in different contexts. We show that using surrogate data built using a method developed in the case of uniform population sampling yields an improvement with respect to the use of the sampled data but is strongly limited by the underestimation of the link density in the sampled network. We put forward a second method to build surrogate data that assumes knowledge of the density of links within one of the groups forming the population. We show that it gives very good results when the population is strongly structured, and discuss its limitations in the case of a population with a weaker group structure. These limitations highlight the interest of measurements using wearable sensors able to yield accurate information on the structure and durations of contacts

Epidemic risk from friendship network data: an equivalence with a non-uniform sampling of contact networks

Contacts between individuals play an important role in determining how infectious diseases spread. Various methods to gather data on such contacts co-exist, from surveys to wearable sensors. Comparisons of data obtained by different methods in the same context are however scarce, in particular with respect to their use in data-driven models of spreading processes. Here, we use a combined data set describing contacts registered by sensors and friendship relations in the same population to address this issue in a case study. We investigate if the use of the friendship network is equivalent to a sampling procedure performed on the sensor contact network with respect to the outcome of simulations of spreading processes: such an equivalence might indeed give hints on ways to compensate for the incompleteness of contact data deduced from surveys. We show that this is indeed the case for these data, for a specifically designed sampling procedure, in which respondents report their neighbors with a probability depending on their contact time. We study the impact of this specific sampling procedure on several data sets, discuss limitations of our approach and its possible applications in the use of data sets of various origins in data-driven simulations of epidemic processes

Linguistics during the 19th century between description and norm: a study of the patois boulonnais by Daniel Haigneré

L’article s’intéresse aux deux tomes écrits par Daniel Haigneré (1824-1893) sur son patois natal bas-boulonnais (Pas-de-Calais) publiés en 1901 et 1903. La première partie s’intéresse à l’approche suivie par Haigneré dans son entreprise descriptive et montre qu’il s’est comporté en grammairien plutôt qu’en linguiste. La deuxième partie est une étude comparée de deux traductions de la Parabole de l’enfant retrouvé en patois boulonnais, publiées en 1807 et 1888, la deuxième étant de Haigneré lui-même.The paper deals with the two tomes by Daniel Haigneré (1824-1893) on his native “basboulonnais” dialect (Pas-de-Calais) published in 1901 and 1903. The first part focuses on the approach applied by Haigneré in his descriptive undertaking and shows that he reasoned as a grammarian rather than a linguist. The second part is a comparative study of two translations of the Parable of the Prodigal Son in Boulonnais dialect, published in 1807 and 1888, the latter due to Haigneré himself

L'évaluation du processus d'autoformation des cadres européens de la net-économie

L'objectif principal de la recherche est d'analyser les fonctions que revêt la formation continue pour les cadres des entreprises de la net-économie lorsqu'ils sont confrontés à de nouvelles formes de fragilisation professionnelle. Les enquêtes de terrain portent sur mille dirigeants ou cadres de start-up, d'entreprises de services informatiques consultés sur « l'arc méditerranéen » (Espagne, France, Italie, Grèce et Chypre). L'hypothèse centrale du point de vue des sciences de l'éducation est que la formation professionnelle continue offre une réponse efficace à la précarisation paradoxale de ces personnels hautement qualifiés dès lors qu'elle est individuellement anticipée et collectivement garantie

La formation et l'emploi : nouveaux défis, pour quels changements ?

L'article montre que les dirigeants de PME-PMI se représentent les actions de formation continue dans un cadre fortement marqué par la théorie économique néo classique de l'offre et de la demande. L'innovation rendue possible par les NTIC en matière de formation continue doit davantage prendre en compte les potentiels individuels, mais aussi collectifs

Le dialecte germanique atteste dans les toponymes de l'ancien comte de Boulogne-sur-mer (Pas-de Calais)

The paper deals with toponyms in the area around Boulogne-sur-mer (Pas-de-Calais). A fair number of them do not belong to the Frankish and Gallo-Romans layers, which can be found in the rest of Northern France. They derive from another source, obviously Germanic but with stronger links with Normandy and England. From the toponymic data the main phonological features of this dialect can be retrieved within the comparative framework of Germanic, of its Westic branch for the most part but with some Norse components. A glossary of this dialect, which stands half-way between English and Saxon, can be created. It is also possible to determine how this linguistic intrusion was gradually absorbed by French, represented by the so-called “Picard” dialect. The paper focuses on the westernmost part of the Pas-de-Calais. References to neighboring areas within the Pas-de-Calais exemplify the contrasts with the area under survey. The ancient forms of the toponyms and the dates of their attestations are taken from the compilation in Poulet (1997). They can be checked in Haigneré (1881).L’article s’intéresse aux toponymes dans la région autour de Boulogne-sur-mer (Pas-de-Calais). Un bon nombre d’entre eux diffèrent des couches franques et gallo-romaines que l’on peut rencontrer dans le reste du nord de la France. Ils dérivent en fait d’une autre source, certes germanique mais montrant des affinités plus fortes avec la Normandie et l’Angleterre. Le matériel toponymique permet de retrouver les principales caractéristiques phonologiques de cet idiome dans une perspective comparative au sein du germanique, dans sa branche westique pour l’essentiel avec quelques éléments plus rares relevant de la branche nordique. Il est en outre possible de dresser un glossaire de cette variété dialectale à mi-chemin entre l’anglais et le saxon. Il est également possible d’examiner comment cette intrusion fut absorbée graduellement par le français, sous sa forme dialectale dite « picarde L’article se focalise sur la partie la plus à l’ouest du Pas-de-Calais. Les références aux régions voisines du Pas-de-Calais ont surtout une visée contrastive par rapport à la zone étudiée. Les formes anciennes des toponymes et les dates de leurs attestations sont tirées pour l’essentiel de la compilation réalisée par Poulet (1997). Elles peuvent également être vérifiées dans Haigneré (1881)