A Unified Multimedia and Semantic Perspective for Data Retrieval in the Semantic Web

In recent years, the emerging diffusion of peer-to-peer networks isgoing beyond the single-domain paradigm like, for instance, themonothematic file sharing one (e.g., Napster for music). Peers aremore and more heterogeneous data sources which need to share data with commercial, educational, and/or collaboration purposes, just tomention a few. Moreover, in current information processingapplications data can not be meaningfully searched by precise database queries that would return exact matches (e.g., when dealing with multimedia, proteomic, statistical data).In this paper we move a step towards multi-domain multi-type datasharing systems by introducing an advanced technologicalinfrastructure which enables users to meet these new emerging needs.A fundamental issue in this context is data heterogeneity, which ispervasive and intrinsically present both at intensional level where,due to peers’ autonomy, different semantic descriptions of theavailable information are provided, and at extensional level, wheremultiple data types can coexist, also including content-basedsearchable data types such as multimedia data.Our proposal relies on a Peer Data Management Systems (PDMS) framework to present innovative network organization and query routing mechanisms which exploit both peers’ data description and data content to achieve effective and efficient network management and data retrieval in such a context. The validity of our proposal isdemonstrated by an absolutely satisfactory experimental evaluation ona real setting.