rdf icons Research Project done by Semantic Computing Research Lab,

Compputer Science Department, North Carolina State University.   June 22, 2009

 

Retrospective Interpretation of Keyword Queries on RDF Databases

Abstract: Earlier efforts on supporting keyword queries on structured databases focused on the IR-style of simply returning subgraph matches of keywords that users need to filter through. More recent approaches, particularly in the context of querying RDF databases, place an emphasis on explicitly “interpreting” or “structurizing” a keyword query prior to answering it. A key challenge that must be overcome in this respect is that of dealing with the large number of candidate query interpretations due to the inherent ambiguity of keyword queries. Different heuristics, based on statistical and structural properties of the database have been proposed, but these approaches do not consistently produce good results. One important direction that remains unexplored is the use of query history for contextualizing a query, enabling aggressive pruning of the space of candidate interpretations.

This paper addresses the problem of retrospectively interpreting (structurizing) a keyword query on an RDF database using information in a query log. It contributes a dynamic cost model for capturing the relative relevance of schema segments for a given query in a way that distinguishes current and aging querying contexts. It further contributes a novel indexing technique for finding and updating the top-K most relevant schema segments that as new queries enter and older queries “age-out” of querying contexts. Finally, it contributes a context-aware top-K query generation algorithm that generates a list of K structured queries that contain the most likely intended interpretations for a given keyword query. Experimental results on effectiveness using extended precision and recall measures and scalability are presented that show very promising results.

Keywords: Keyword Query, RDF, Disambiguation, Query History, Query Interpretation

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