Guiding queries to information sources with infobeacons

Abstract

The Internet provides a wealth of useful information in a vast number of dynamic information sources, but it is difficult to determine which sources are useful for a given query. Most existing techniques either require explicit source cooperation (for example, by exporting data summaries), or build a relatively static source characterization (for example, by assigning a topic to the source). We present a system, called InfoBeacons, that takes a different approach: data and sources are left "as is," and a peer-to-peer network of beacons uses past query results to "guide" queries to sources, who do the actual query processing. This approach has several advantages, including requiring minimal changes to sources, tolerance of dynamism and heterogeneity, and the ability to scale to large numbers of sources. We present the architecture of the system, and discuss the advantages of our design. We then focus on how a beacon can choose good sources for a query despite the loose coupling of beacons to sources. Beacons cache responses to previous queries and adapt the cache to changes at the source. The cache is then used to select good sources for future queries. We discuss results from a detailed experimental study using our beacon prototype which demonstrates that our "loosely coupled" approach is effective; a beacon only has to contact sixty percent or less of the sources contacted by existing, tightly coupled approaches, while providing results of equivalent or better relevance to queries. © IFIP International Federation for Information Processing 2004.