NEPOMUK Deliverable D5.3: Social Network Software

Executive summary

In the context of Nepomuk- The Social Semantic Desktop - the social aspect is brought in mainly by WP5000: the social networking components are utilized to build and maintain topic- and content-specic interconnections between distributed individual workspaces and to enable integration among them. The main topics considered are the ones dealing with resource exchange, different kinds of recommendations, information integration and querying, as well as the preservation (synchronization) of resources shared in social spaces.

Several Interaction Spaces are presented, describing the interactions among Co-Workers, Communities of Experts, and Social Spaces. Co-workers have usually a very close interaction, where day to day bounds and much information exchange exists. Communities of Experts are groups where people usually do not know each other personally, but rather from references in publications, or other kinds of information sources. Social Spaces, sometimes including but certainly trespassing the working environment, bring together friends over Web2.0 platforms, where not only thoughts, but also multimedia material is shared.

Orthogonal to the Interaction Spaces, there are different ways people or systems can interact in different Ways of Interaction. The presented ways of interaction are Sharing, Recommendations, Querying, Social Integration and Synchronization, as well as Networking. In particular, Sharing represents the targeted exchange of information with certain selected people, while Recommendations is the interaction which provides hints or recommends certain information resources based on some specied need. Querying is the part of a search process where systems are inspected in order to nd what was requested (additionally, overcoming representation heterogeneity). Social Synchronization involves the process of locally preserving some content shared in social sites, and Networking is the action of getting in contact with other people which have similar goals or interest.

After the discussion of the state of the art and the related work, a matrix relating both, the Interaction Spaces and the Ways of Interaction is presented, showing in which areas we focus our attention and our work on, so that it is clear which problems have been tackled. The different Ways of Interaction are reected in several components, providing solutions to them, either alone or in collaboration with other components within WP5000, but also from other workpackages. Besides Sharing of metadata and les, also the execution of conjunctive queries over a P2P infrastructure has been accomplished and evaluated in the project. Another aspect of querying, involving the retrieval of information from heterogeneously represented information, via the exploitation of existing mappings, but also employing query relaxation strategies has been designed, implemented, integrated and evaluated. The different kinds of recommendations designed, implemented and evaluated in the project, ranging from les, metadata and tags from the community, to experts with some expertise, as well as the detection and search of communities of users having common interests on a topic were accomplished. A comprehensive study of the problems and aspects to be considered when synchronizing local desktops with existing Web2.0 sites has been performed, and a prototypical implementation has been integrated into the Aperture framework which is also used in other parts of Nepomuk.

All presented results have been fully integrated into the Nepomuk framework and have been evaluated thoroughly, giving also the opportunity to present this work at many scientic conferences.