Section: New Results

Models for Web data management

Participants : Serge Abiteboul, Emilien Antoine, Meghyn Bienvenu, Alban Galland.

A book on Web Data Management and Distribution [54] was published this year.

A rule-based language for Web data management

We recently proposed [26] a Datalog-style rule-based language (called Webdamlog) for web data management. A novel feature of our language is delegation, that is, the possibility of installing a rule at another peer. In its simplest form, delegation is essentially a remote materialized view. In its general form, it allows peers to exchange rules, i.e., knowledge beyond simple facts, and thereby provides the means for a peer to delegate work to other peers.

A key contribution of our work is a study of the impact on expressiveness of delegations and explicit timestamps. We showed that both strictly augment the power of the language. In order to validate the semantics of our model, we demonstrated that under certain natural conditions, our semantics converges to the same semantics as the centralized system with the same rules.

Web information management with access control

We investigated the problem of sharing private information on the Web, where the information is hosted on different machines that may use different access control and distribution schemes. Based upon our work on Webdamlog, we introduced a distributed knowledge-base model, termed WebdamExchange, that comprises logical statements for specifying data, access control, distribution and knowledge about other peers. In a demo at ICDE [28] , we showed how the model can be used in a social-network context to help users keep control on their data on the web. In particular, we demonstrated how users within very different schemes of data distribution (centralized, DHT, unstructured P2P, etc.) can still transparently collaborate while keeping a good control over their own data.