Full potential calculations and atom in molecule analysis of the bonding properties of perovskites Borides XRh

ab initio calculations were performed for the cubic perovskites Borides XRh3B, (X=Dy, Ho, Er). In this work, we have used the augmented plane-wave plus local orbital method to compute the equilibrium structural parameters and electronic structure of densities of states, as well as for the first time, prediction of the thermo-elastic properties of these crystals are presented. The chemical bonding of these compounds has been investigated by using of topological analyses grounded in the theory of atoms in molecules (AIM). All of the electron density critical points in the unit cell were systematically calculated in order to calculate basins interaction of each atoms and give exact classification of the bonding character

Elliptic Curve-Based Secure Multidimensional Aggregation for Smart Grid Communications

International audienceIn smart grid, data aggregation is considered as an essential paradigm in assessing information about current energy usage. To achieve the privacy-preserving goal, several homomorphic-based solutions have been proposed. However, these solutions either consider one-dimensional information or use costly pairing computation in order to ensure source authentication. In fact, smart grid data are likely to be multidimensional (e.g., time, purpose, and so on) for more accurate control. In addition, the aggregation node in smart grid needs to verify data that come from several smart meters in a residential area; hence, the verification must be cost-efficient. In this paper, we propose a scheme that considers multidimensional aggregation with privacy preserving and an efficient verification of smart grid data. The proposal is based on elliptic curve cryptography along with homomorphic encryption and without pairings. The performance analysis shows the efficiency of the scheme for smart grid communications in comparison with existing schemes. For instance, we show that, when an aggregator node is responsible of 600 smart meters, it spends approximately 14 s to verify the data in pairing-based schemes, while only 0.3 s is needed for verification within the proposed scheme

Two-Levels Verification for Secure Data Aggregation in Resource-Constrained Environments

International audienceMany resource-constrained applications make use of data aggregation in order to prolong the network lifetime. However, the resource-constrained devices are usually deployed in unattended environments in which providing security is of paramount importance. This leads to various attacks that can occur during data aggregation process. Internal attacks such as selective forwarding represent the most dangerous ones since they cannot be detected by existing cryptography- based protocols proposed to secure data aggregation. In this work, we propose a two-levels verification, in which data is verified using cryptography and intrusion detection techniques. Indeed, a lightweight homomorphic encryption is combined with a game-theory based technique to efficiently secure data aggregation. Our analysis and results show the applicability of the system for aggregation-based resource-constrained applications, especially those considering sensitive information (e.g. health monitoring, military) where the time-efficient detection is crucial

Effets des Raidisseurs de Platine d'about sur les Assemblages Boulonnes de type Poteau-Poutre

International audienceLe présent papier a pour but d'étudier le comportement mécanique des assemblages métalliques poteau poutre boulonnés par platine d'about raidie à ses débords sous à un moment de flexion. L'étude est basée sur un modèle en éléments finis qui tient compte des non-linéarités géométriques, matérielles et celles du contact entre les éléments. Les résultats du modèle numérique ont été validés sur la base des résultats expérimentaux disponibles dans la littérature et comparés avec le modèle analytique proposé par l'Eurocode 3 et. Une étude paramétrique est menée afin de mettre en évidence l'effet des raidisseurs de platine d'about en zone tendue et comprimée de l'assemblage