Taming the interoperability challenges of complex IoT systems

of communication protocols and data formats; hence ensuring diverse devices can interoperate with one another remains a significant challenge. Model-driven development and testing solutions have been proposed as methods to aid software developers achieve interoperability compliance in the face of this increasing complexity. However, current approaches often involve complicated and domain specific models (e.g. web services described by WSDL). In this paper, we explore a lightweight, middleware independent, model-driven development framework to help developers tame the challenges of composing IoT services that interoperate with one another. The framework is based upon two key contributions: i) patterns of interoperability behaviour, and ii) a software framework to monitor and reason about interoperability success or failure. We show using a case-study from the FI-WARE Future Internet Service domain that this interoperability framework can support non-expert developers address interoperability challenges. We also deployed tools built atop the framework and made them available in the XIFI large-scale FI-PPP test environment

Применение модифицированного метода транспортирующей траектории при оптимизации межпланетных перелетов с комбинированием большой и малой тяги

Запропоновано підхід до побудови оптимальних траєкторій міжпланетних перельотів з комбінуванням великої та малої тяги, оснований на застосуванні модифікованого методу транспортуючої траєкторії для оптимізації геліоцентричної ділянки. На прикладі перельоту Земля - Марс за 180 діб проведено порівняльний аналіз траєкторій і параметрів космічного апарату, оптимальних під час застосування класичного та модифікованого методів транспортуючої траєкторії.An approach is proposed to construct the optimal trajectories of interplanetary transfers with combination of the high trust and low trust. It is based on using the modified method of carrying trajectory to optimize the heliocentric part of trajectory. On an example of transfer Earth – Mars with duration of 180 astronomical days, a comparative analysis is carried out for trajectories and parameters of spacecraft, which are optimal, when the classic and modified methods of carrying trajectory are using

Analyse de l'activité décisionnelle de joueurs de football dans un environnement virtuel. Effets des changements de point de vue

International audienceL'étude des processus sous-jacents à l'activité décisionnelle dans les situations dynamiques, que se soit dans le domaine du travail ou du sport, devient un élément essentiel à la conception d'outils de formation. Les simulations virtuelles constituent à la fois des outils privilégiés d'étude de ces processus et de formation. Notre travail a consisté à analyser l'activité de joueurs au sein du simulateur virtuel CoPeFoot et l'influence du changement de point de vue sur cette dernière. Des données comportementales ont été enregistrées auprès de quatre joueurs suivant deux points de vue (immersif et global), puis complétées par des données verbales recueillies lors d'entretiens d'autoconfrontation. L'analyse du contenu des données obtenues permet d'identifier 24 schémas activés par les joueurs sur le simulateur en situation de forte pression temporelle. Ces schémas constituent des structures d'arrière-plans articulant des composantes perceptives et cognitives et qui facilitent la reconnaissance rapide de situations de jeu. La discussion de ces résultats pointe l'aspect dynamique de l'activité décisionnelle au sein du simulateur et l'homogénéité des résultats obtenus en vue immersive et globale. De plus, la concordance avec les conclusions d'études réalisées en situation naturelle permet de proposer des perspectives d'évolution vers un outil de formation à l'activité décisionnelle

Diffusion tensor imaging of the rotator cuff muscles : optimisation of b value and number of diffusion direction for imaging at 3 Tesla MRI

Background: Diffusion tensor imaging is a standard method for evaluation of musculoskeletal pathology. The objective of this study is to determine the optimal b-value and number of diffusion direction for diffusion tensor imaging of rotator cuff muscles in healthy subjects on 3.0 Tesla MRI. Methodology: 38 healthy volunteers were included in this prospective study. Diffusion tensor imaging (DTI) of the rotator cuff muscles (subscapularis, supraspinatus and infraspinatus muscles) was performed with single-shot spin-echo echo-planar imaging sequences in 16 and 32 diffusion directions. Three different b-values were selected for each diffusion direction: b-value 400 s/mm2, 600s/mm2 and 800s/mm2. Signal to noise ratio (SNR) was measured in each muscle at different b-values and number of diffusion direction, and average SNR were calculated. Statistical analysis was performed with one-way ANOVA and paired t-test. Mean and standard deviation were obtained for each DTI parameters, and level of significance was determined (p < 0.05). Results: The signal to noise ratio was highest for all three muscles at b-value 400s/mm2 (subscapularis, 40.255; supraspinatus, 38.203; and infraspinatus, 48.232) followed by b-value 600s/mm2 and 800s/mm2. The use of 32 number of diffusion directions had shown to improve SNR value compared to 16 diffusion directions (P<0.05). Conclusions: The optimal combination of b value and number of diffusion directions in DTI of rotator cuff muscles on 3.0 Tesla MRI is 400s/mm2 and 32 directions respectively

Sentiment de performance collective en phase d'attaque en Handball : vers des pistes de conception

International audienceA partir du cadre de la Team cognition, l'objectif est de cette étude est d'analyser le sentiment de performance collective au sein d'une équipe féminine de handball. Des données comportementales complétées par des données verbales ont été recueillies. Les données ont été traitées sur la base d'une analyse qualitative et inductive. Les résultats ont permis d'identifier des relations entre le sentiment de performance collective et la nature, la forme et les processus de partage. A partir de nos résultats, la discussion se structure autour des pistes de conception envisageables grâce à la réalité augmentée

Special issue on the theory and practice of differential privacy

This special issue presents papers based on contributions to the first international workshop on the “Theory and Practice of Differential Privacy” (TPDP) held in London, UK, 18 April 2015, as part of the European joint conference on Theory And Practice of Software (ETAPS). Differential privacy is a mathematically rigorous definition of the privacy protection provided by a data release mechanism: it offers a strong guaranteed bound on what can be learned about a user as a result of participating in a differentially private data analysis. Researchers in differential privacy come from several areas of computer science, including algorithms, programming languages, security, databases and machine learning, as well as from several areas of statistics and data analysis. The workshop was intended to be an occasion for researchers from these different research areas to discuss the recent developments in the theory and practice of differential privacy. The program of the workshop included 10 contributed talks, 1 invited speaker and 1 joint invited speaker with the workshop “Hot Issues in Security Principles and Trust” (HotSpot 2016). Participants at the workshop were invited to submit papers to this special issue. Six papers were accepted, most of which directly reflect talks presented at the workshop

An Optimal Algorithm to Compute the Inverse Beacon Attraction Region

The beacon model is a recent paradigm for guiding the trajectory of messages or small robotic agents in complex environments. A beacon is a fixed point with an attraction pull that can move points within a given polygon. Points move greedily towards a beacon: if unobstructed, they move along a straight line to the beacon, and otherwise they slide on the edges of the polygon. The Euclidean distance from a moving point to a beacon is monotonically decreasing. A given beacon attracts a point if the point eventually reaches the beacon. The problem of attracting all points within a polygon with a set of beacons can be viewed as a variation of the art gallery problem. Unlike most variations, the beacon attraction has the intriguing property of being asymmetric, leading to separate definitions of attraction region and inverse attraction region. The attraction region of a beacon is the set of points that it attracts. It is connected and can be computed in linear time for simple polygons. By contrast, it is known that the inverse attraction region of a point - the set of beacon positions that attract it - could have Omega(n) disjoint connected components. In this paper, we prove that, in spite of this, the total complexity of the inverse attraction region of a point in a simple polygon is linear, and present a O(n log n) time algorithm to construct it. This improves upon the best previous algorithm which required O(n^3) time and O(n^2) space. Furthermore we prove a matching Omega(n log n) lower bound for this task in the algebraic computation tree model of computation, even if the polygon is monotone

Entre méfiance et accueil

Les étrangers constituent un véritable enjeu pour les ducs de Bretagne qui développent, à la fin du Moyen Âge, une politique d’indépendance. Ils s’efforcent de sécuriser les côtes, en première ligne des exactions ennemies. Leur défense passe par la mise en place d’une marine de guerre, la mobilisation des sujets et des travaux de fortification, dispositif vécu comme une contrainte pour les habitants. Le pouvoir ducal s’attache, en même temps, à favoriser les échanges maritimes et à protéger la venue des marchands étrangers par un cadre diplomatique et judiciaire adapté. Ce volontarisme est aussi motivé par le désir de réglementer la présence étrangère afin d’en tirer profit. Ce développement institutionnel est certes incomplet, mais il a contribué à renforcer la présence des autorités sur les littoraux.Migrants from abroad were a real challenge for the Dukes of Brittany who were establishing a policy of independence at the end of the Middle Ages. They made sure the coastline was secure since it was on the front line of enemy attacks. The defence works included the construction of a navy, mobilisation of their subjects and building of fortifications; this system was felt to be very restrictive by the inhabitants. At the same time, the Duchy endeavoured to encourage sea-based trade and to protect the movements of foreign merchants with a specific diplomatic and legal framework. This positive action was also motivated by the wish to legislate on the presence of foreigners in order to make money from them. This institutional development was certainly incomplete but it helped to reinforce the presence of the authorities on and near the coastline