Hiding in the Crowd: A Massively Distributed Algorithm for Private Averaging with Malicious Adversaries

The amount of personal data collected in our everyday interactions with connected devices offers great opportunities for innovative services fueled by machine learning, as well as raises serious concerns for the privacy of individuals. In this paper, we propose a massively distributed protocol for a large set of users to privately compute averages over their joint data, which can then be used to learn predictive models. Our protocol can find a solution of arbitrary accuracy, does not rely on a third party and preserves the privacy of users throughout the execution in both the honest-but-curious and malicious adversary models. Specifically, we prove that the information observed by the adversary (the set of maliciours users) does not significantly reduce the uncertainty in its prediction of private values compared to its prior belief. The level of privacy protection depends on a quantity related to the Laplacian matrix of the network graph and generally improves with the size of the graph. Furthermore, we design a verification procedure which offers protection against malicious users joining the service with the goal of manipulating the outcome of the algorithm.Comment: 17 page

La Font du Pin : an outpost of the pliocene sea at the foot of the Luberon mounts

Les sédiments marins d’âge pliocène ont été décrits en bordure sud du Luberon ainsi que leur abondante microfaune. Un affleurement supplémentaire a été mis en évidence à La Font du Pin, près de Cheval Blanc (Vaucluse).Les argiles sableuses estuariennes sont riches en débris de lamellibranches mais surtout en foraminifères et ostracodes. Ces argiles représentent le témoin le plus septentrional de l’estuaire marin durancien s’orientant au sud vers le détroit de St-Pierre-de-Vence.Marine sediments of Pliocene age are well known around the southern border of the Luberon. An as yet undesc ribed outcrop of sandy estuarine clays, rich in lamellibranch debris, Foraminifera ,Ostracods was found at La Font du Pin (Cheval Blanc, Vaucluse).It is the northernmost witness of the Basse Durance pliocene seaway, then bending southwards through the Alpilles straits of St-Pierre-de-Vence

Hiding in the Crowd: A Massively Distributed Algorithm for Private Averaging with Malicious Adversaries

The amount of personal data collected in our everyday interactions with connected devices offers great opportunities for innovative services fueled by machine learning, as well as raises serious concerns for the privacy of individuals. In this paper, we propose a massively distributed protocol for a large set of users to privately compute averages over their joint data, which can then be used to learn predictive models. Our protocol can find a solution of arbitrary accuracy, does not rely on a third party and preserves the privacy of users throughout the execution in both the honest-but-curious and malicious adversary models. Specifically, we prove that the information observed by the adversary (the set of maliciours users) does not significantly reduce the uncertainty in its prediction of private values compared to its prior belief. The level of privacy protection depends on a quantity related to the Laplacian matrix of the network graph and generally improves with the size of the graph. Furthermore, we design a verification procedure which offers protection against malicious users joining the service with the goal of manipulating the outcome of the algorithm

LES DETERMINANTS MECANIQUES ET NEUROPHYSIOLOGIQUES DE LA PERFORMANCE EN TIR A L’ARC : INCIDENCES SUR L’ENTRAINEMENT

International audienceL’objectif de ce travail est de caractériser les stratégies musculaires intervenant dans le tir àl’arc, mais également de déterminer leur évolution au décours de la fatigue. Ainsi l’influencede l’apparition d’un phénomène de fatigue neuro-musculaire sur la performance en tir à l’arcpourra être déterminée. Une programmation spécifique de renforcement musculaire pourraalors être établie dans le double objectif d’améliorer la performance, mais également deréduire les risques de pathologie de l’épaule

Enabling comprehensive optogenetic studies of mouse hearts by simultaneous opto-electrical panoramic mapping and stimulation

During the last decade, cardiac optogenetics has turned into an essential tool for investigating cardiac function in general and for assessing functional interactions between different myocardial cell types in particular. To advance exploitation of the unique research opportunities offered by this method, we develop a panoramic opto-electrical measurement and stimulation (POEMS) system for mouse hearts. The core of the experimental platform is composed of 294 optical fibers and 64 electrodes that form a cup which embraces the entire ventricular surface of mouse hearts and enables straightforward 'drop&go' experimentation. The flexible assignment of fibers and electrodes to recording or stimulation tasks permits a precise tailoring of experiments to the specific requirements of individual optogenetic constructs thereby avoiding spectral congestion. Validation experiments with hearts from transgenic animals expressing the optogenetic voltage reporters ASAP1 and ArcLight-Q239 demonstrate concordance of simultaneously recorded panoramic optical and electrical activation maps. The feasibility of single fiber optical stimulation is proven with hearts expressing the optogenetic voltage actuator ReaChR. Adaptation of the POEMS system to larger hearts and incorporation of additional sensors can be achieved by redesigning the system-core accordingly

Probabilistic Determination of the Role of Faults and Intrusions in Helium‐Rich Gas Fields Formation

Natural gas fields with economic helium (>0.3 He %) require the radioactive decay of crustal uranium (U) and thorium (Th) to generate He and tectonic/structural regimes favorable to releasing and concentrating He. An unknown is determining the role of faults and structural features in focusing deep‐seated He sources on shallow accumulations. We tested the correlation between high‐He wells (n = 94) and structural features using a new high‐resolution aeromagnetic survey in the Four Corners area, USA. A depth‐to‐basement map with basement lineaments/faults, an intrusion map, and a flattened basement structural high map were created using Werner deconvolution algorithms by combining magnetic, gravity, and topography data with magnetic and gravity depth profiles. We show quantitatively (via analysis of variance) that a non‐random process controls the relationship between He (>0.3%) and both basement faults and intrusions: 88% of high‐He wells occur <1 km of basement faults; and 85% of high‐He wells occur <1 km of intrusions. As He % increases, the distance to the structural features decreases. Strong spatial/statistical correlations of He wells to both basement faults and intrusions suggest that advective transport via faults/intrusions facilitates He migration. The role of gas phase buoyancy and structural trapping is confirmed: 88% of high‐He occurs within basement structural highs, and 91% of the remaining wells are <1 km from intrusions (potential structural high). We present a composite figure to illustrate how a probabilistic approach can be used as a predictive model to improve He exploration success by targeting zones of intersection of basement faults and intrusions within basement structural highs

Evaluation de la stratégie de lutte contre le cancer en Suisse, Phase 2, 2002 : document de synthèse

[Table des matières] 1. Introduction. 2. Méthode. 3. Conclusions et recommandations générales. 3.1. Stratégie. 3.2. Conclusions et recommandations concernant la stratégie, les structures et le fonctionnement, la collaboration avec l'extérieur. 3.3. Les 4 programmes nationaux. 3.4. Conclusions et recommandations pour les 4 programmes nationaux. 3.5. Bilan de l'expérience de la mise en place du dépistage du sein. 3.6. Conclusions et recommandations pour la mise en place du dépistage du sein. 3.7. Les données à disposition pour le suivi et l'évaluation de la stratégie nationale de lutte contre le cancer. 3.8. Conclusions et recommandations pour le suivi et l'évaluation de la stratégie nationale de lutte contre le cancer. 4. Annexes: Résumés des études 1 à 7. Etude 1: Suivi du développement de la stratégie nationale. Studie 2: Prozessevaluation und Prozessdokumentation. Studie 3: Mammographie-Screening in der Schweiz : eine retrospektive Analyse zur Umsetzung. Studie 4: Sekundäre Analyse der verfügbaren Indikatoren zur Messung der Ergebnisse des nationalen Krebsbekämpfungsprogrammes. Etude 5: Quel ancrage local des actions de la Ligue suisse contre le cancer ? : l'exemple de la prévention du mélanome. Studie 6: Begleitevaluation der Pilotphase des Aktionsmonats Brustkrebs. Etude 7: Accompagnement psychosocial des personnes ayant un diagnostic de cancer : étude de deux cantons