In recent years, several important content providers such as Amazon,
Musicbrainz, IMDb, Geonames, Google, and Twitter, have chosen to
export their data through Web services. To unleash the potential of
these sources for new intelligent applications, the data has to be
combined across different APIs.
To this end, we have developed ANGIE, a framework that maps the
knowledge provided by Web services dynamically into a local knowledge
base. ANGIE represents Web services as views with binding patterns
over the schema of the knowledge base. In this talk, I will focus on
two problems related to our framework.
In the first part, the focus will be on the automatic integration of
new Web services. I will present a novel algorithm for inferring the
view definition of a given Web service in terms of the schema of the
global knowledge base. The algorithm also generates a declarative
script can transform the call results into results of the view. Our
experiments on real Web services show the viability of our approach.
The second part will address the evaluation of conjunctive queries
under a budget of calls. Conjunctive queries may require an unbound
number of calls in order to compute the maximal answers. However, Web
services typically allow only a fixed number of calls per session.
Therefore, we have to prioritize query evaluation plans. We are working on distinguishing among all plans that could return answers those plans
that actually will. Finally, I will show an application for this new notion of plans.
Nicoleta Preda obtained her Ph.D. in computer science from the University Paris-Sud under the supervision of Serge Abiteboul and Ioana Manolescu. Before joining the University of Versailles in 2010, she was a post-doctoral researcher in the database group led by Gerhard Weikum at the Max Planck Institute for Informatics. Her research interests include the enrichment of KBs with dynamic data, rule mining, and querying large repositories of semi-structured data. Nicoleta teaches classes on data integration, database systems, XML technologies, and Web services.