Room Change: Fall Seminar on Data and Knowledge Integration: this week

[Chitta Baral <chitta@asu.edu>]

The room is GWC 308 for this week, as 487 was
not available. We will be back in 487 from next week.

Chitta

Chitta Baral wrote:
> 
> The sixth talk of the seminar series
>   will be this Friday.
> 
>    Date: 10/11/02 (Friday)
>    Time: 11:00 -- 12:15 PM
>    Place: GWC 487
            ^^^^308
> 
>   Speaker: K. Selcuk Candan
> 
> He plans to present the paper
> "On the Expressive Power of Data Integration Systems" by
> Cali, Calvanese, De Giacomo, and Lenzerini.
> 
> This paper is about to be presented at 21st Int. Conf. on Conceptual
> Modeling (ER 2002), and here is its abstract (taken directly from the
> paper)
> 
> "There are basically two approaches for designing a data integration
> system. In the global-as-view (GAV) approach, one maps the concepts in
> the global schema to views over the sources, whereas in the
> local-as-view (LAV) approach, one maps the sources into views over the
> global schema. The goal of this paper is to relate the two approaches
> with respect to their expressive power. The analysis is carried out in a
> relational database setting, where both the queries on the global
> schema, and the views in the mapping are conjunctive queries. We
> introduce the notion of query-preserving transformation, and
> query-reducibility between data integration systems, and we show that,
> when no integrity constraints are allowed in global schema, the LAV and
> the GAV approaches are incomparable. We then consider the addition of
> integrity constraints in the global schema, and present techniques for
> query-preserving transformations in both directions. Finally, we show
> that our results imply that w!
> e can always transform any system following the GLAV approach (a
> generalization of both LAV and GAV) into a query-preserving GAV system."
> 
> The paper is available at
> http://www.dis.uniroma1.it/~calvanes/papers-html/ER-2002.html
> 
> 
> --
>  Chitta Baral
>  Dept. of Computer Sc. and Engg.,
>  Arizona State University, Tempe, AZ 85287, USA.
>  chitta@asu.edu, http://www.public.asu.edu/~cbaral/
>  Ph: 480-727-6047, Fax: 480-965-2751

-- 
 Chitta Baral
 Dept. of Computer Sc. and Engg.,
 Arizona State University, Tempe, AZ 85287, USA.
 chitta@asu.edu, http://www.public.asu.edu/~cbaral/
 Ph: 480-727-6047, Fax: 480-965-2751