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Reverse dynamics is crucial in machine structure analysis which determines the relationship between the operating point and the torque excitation on the active link of the machine. The main structure of the MB-250 CNC optical grinding machine is composed of an independent rotated grinding disc that is attached to the planar four-bar mechanism. First, the motion equations of a mechanism will be established using the matrix form of Lagrangian equations using multipliers for constrained multibody systems. Then, a reverse dynamic algorithm was used to determine the torque acting on the active link of the machine. The study was conducted and verified by combining experiments with numerical simulations. The research results are used to actively control the grinding trajectory, velocity, and acceleration of the operating point to enhance the surface quality of the products.

The social media have played an increasingly important role in many areas of our every day life. Among others, social network sites such as Facebook, LinkedIn, Twitter and Google+ have recently exploded in popularity by attracting millions of users, who communicate with each other, share and publish information and contents at an unprecedented rate. Besides the recognized advantages, social network sites have also raised various issues and challenges. We are particularly interested in two of them, information overload and "walled gardens". These two problems prevent the users from fully and efficiently exploiting thewealth of information available on social network sites. The users have difficulties to filter all incoming contents, to discover additional contents from outside of their friend circles, and importantly to share interesting contents with their different groups of interest. For helping the users to overcome such difficulties, we propose a User-centered and group- based approach for social data filtering and sharing. This novel approach has a twofold purpose : (1) allow the users to aggregate their social data from different social network sites, and to extract from those data the contents of their interest, and (2) organize and share the contents within different groups. The members of a group are moreover able to choose which part of their social data to share with the group, and collectively define its topics of interest. To achieve the proposed approach, we define a modular system architecture including a number of extensible modules, and accordingly build a working Web-based prototype, called SoCoSys. The experimental results, obtained from the two different tests, confirm the added values of our approach., Les médias sociaux occupent un rôle grandissant dans de nombreux domaines de notre vie quotidienne. Parmi d'autres, les réseaux sociaux tels que Facebook, Twitter, LinkedIn et Google+ dont la popularité a explosé ces dernières années, attirent des millions d'utilisateurs qui se communiquent, publient et partagent des informations et contenus à un rythme sans précédent. Outre les avantages reconnus, les réseaux sociaux ont également soulevé des problèmes divers. Nous sommes particulièrement intéressés par deux problèmes spécifiques : surcharge d'information et cloisonnement de données. Ces deux problèmes empêchent les utilisateurs d'exploiter pleinement et efficacement la richesse des informations poussées sur les réseaux sociaux. Les utilisateurs ont des difficultés pour filtrer tous les contenus reus, pour découvrir de nouveaux contenus au-delà de leurs réseaux personnels, et surtout pour partager les contenus intéressants avec leurs différents groupes d'intérêt. Pour aider les utilisateurs à surmonter ces difficultés, nous proposons une Approche centrée sur utilisateur et basée groupe pour filtrer et partager des données sociales. Cette nouvelle approche a un double objectif : (1) permettre aux utilisateurs d'agréger leurs données sociales en provenance de différents réseaux sociaux, d'en extraire des contenus de leur intérêt et (2) organiser et partager les contenus au sein de différents groupes. Les membres d'un groupe sont en outre en mesure de choisir quelle partie de leurs données à partager avec le groupe et définir collectivement les sujets d’intérêt de ce dernier. Pour implémenter l'approche proposée, nous spécifions une architecture de système comprenant plusieurs modules extensibles, et nous développons un prototype fonctionnel basé Web, appelé SoCoSys. Les résultats expérimentaux, obtenus des deux tests différents, valident les valeurs ajoutées de notre approche.

International audience; Large scale online social networks (OSN) such as Facebook, Twitter, LinkedIn, have become an important part of our every day life. Users are connected to different social services in which they maintain their own profiles including their friends lists. A consequence of the success of ONS is that the number of Friends of a given user may grow so rapidly that it becomes impossible to manage all updates from friends' profiles and to filter out useful information. We present a FOAF-based profiles aggregation model, which aligns the different profiles models available on the different ONS of the user. Our model can deduce relations and build links between aggregated profiles. These links will allow a user to directly search information from the aggregated profile of another user, without any additional processing. We illustrate the approach by the presentation of some applications in the domain of personal recommendation that rely on our model to provide users with some effective help.

International audience; Online social networks (OSNs) such as Facebook, Twitter, LinkedIn, have become an important part of our every day life. Users are connected to these services in which they maintain their different profiles including lots of personal information, especially interests, competences and professional relationships. On one side, users are rapidly overwhelmed by the giant flux of data, on the other side, organizations, thought interested in some contents posted on OSNs by their collaborators, do not have a real mean to capture this external resource. We present a FOAF-based profiles aggregation model, which connects, aligns the different profiles available on OSNs of the user in a unified profile. The model can also deduce relations and build links between aggregated profiles. A triple store is used to store all user information. By querying specific SPARQL queries against the triple store, we show that some applications can help both users and organizations for efficient people and information searches.

International audience; Numerous works to manage automatically the merge of the various versions of structured textual documents have been developed and correspond to the domain of "XML documents Diff & Merge". We propose in this paper, an alternative named interactive merge. This approach consists in not applying systematically the automatic merge but in keeping the transformation sequential and interactive. The objective is to propose to the user a list of operations associated with the original document, which he/she can confirm or not, according to the objective of the fusion and the detection of conflicts and inconsistencies.