The amount of information on the Web is spreading very rapidly. Users as well as companies bring data to the network and are willing to share with others. They quickly reach a situation where their information is hosted on many machines they own and on a large number of autonomous systems where they have accounts. Management of all this information is rapidly becoming beyond human expertise. We introduce WebdamExchange, a novel distributed knowledge-base model that includes logical statements for specifying information, access control, secrets, distribution, and knowledge about other peers. These statements can be communicated, replicated, queried, and updated, while keeping track of time and provenance. The resulting knowledge guides distributed data management. WebdamExchange model is based on WebdamLog, a new rule-based language for distributed data management that combines in a formal setting deductiverules as in Datalog with negation, (to specify intensional data) and active rules as in Datalog:: (for updates and communications). The model provides a novel setting with a strong emphasis on dynamicity and interactions(in a Web 2.0 style). Because the model is powerful, it provides a clean basis for the specification of complex distributed applications. Because it is simple, it provides a formal framework for studying many facets of the problem such as distribution, concurrency, and expressivity in the context of distributed autonomous peers. We also discuss an implementation of a proof-of-concept system that handles all the components of the knowledge base and experiments with a lighter system designed for smartphones. We believe that these contributions are a good foundation to overcome theproblems of Web data management, in particular with respect to access control.

La masse d’information disponible sur leWeb s’accroit rapidement, sous l’afflux de données en provenance des utilisateurs et des compagnies. Ces données qu’ils souhaitent partager de façon controllée sur le réseau et quisont réparties sur de nombreuses machines et systèmes différents, ne sont rapidement plus gérables directement par des moyens humains. Nous introduisons WebdamExchange, un nouveau modèle de bases de connaissancesdistribuées, qui comprend des assertions au sujet des données, du contrôle d’accés et de la distribution. Ces assertions peuvent être échangées avec d’autres pairs, répliquées, interrogées et mises à jour, en gardant la trace de leur origine. La base de connaissance permet aussi de guider de façon automatique sa propre gestion. WebdamExchange est basé surWebdamLog, un nouveau langage de règles pour la gestion de données distribuées, qui associe formellement les règles déductives de Datalog avec négation et les règles actives de Datalog::. WebdamLog met l’accent sur la dynamicité et les interactions, caractéristiques du Web 2.0. Ce modèle procure à la fois un langage expressif pour la spécification de systèmes distribués complexes et un cadre formel pour l’étude de propriétés fondamentales de la distribution. Nous présentons aussi une implémentation de notre base de connaissance. Nous pensons que ces contributions formentune fondation solide pour surmonter les problèmes de gestion de données du Web, en particulier dans le cadre du contrôle d’accès. / The amount of information on the Web is spreading very rapidly. Users as well as companies bring data to the network and are willing to share with others. They quickly reach a situation where their information is hosted on many machines they own and on a large number of autonomous systems where they have accounts. Management of all this information is rapidly becoming beyond human expertise. We introduce WebdamExchange, a novel distributed knowledge-base model that includes logical statements for specifying information, access control, secrets, distribution, and knowledge about other peers. These statements can be communicated, replicated, queried, and updated, while keeping track of time and provenance. The resulting knowledge guides distributed data management. WebdamExchange model is based on WebdamLog, a new rule-based language for distributed data management that combines in a formal setting deductiverules as in Datalog with negation, (to specify intensional data) and active rules as in Datalog:: (for updates and communications). The model provides a novel setting with a strong emphasis on dynamicity and interactions(in a Web 2.0 style). Because the model is powerful, it provides a clean basis for the specification of complex distributed applications. Because it is simple, it provides a formal framework for studying many facets of the problem such as distribution, concurrency, and expressivity in the context of distributed autonomous peers. We also discuss an implementation of a proof-of-concept system that handles all the components of the knowledge base and experiments with a lighter system designed for smartphones. We believe that these contributions are a good foundation to overcome theproblems of Web data management, in particular with respect to access control.