Louiqa Raschid

Learn More
Access to large numbers of data sources introduces new problems for users of heterogeneous distributed databases. End users and application programmers must deal with unavailable data sources. Database administrators must deal with incorporating each new data source into the system. Database implementors must deal with the transformation of queries between(More)
Accessing many data sources aggravates prob lems for users of heterogeneous distributed databases Database administrators must deal with fragile mediators that is mediators with schemas and views that must be sig ni cantly changed to incorporate a new data source When implementing translators of queries from mediators to data sources database implementors(More)
There is an increase in the number of data sources that can be queried across the WWW. Such sources typically support HTML forms-based interfaces and search engines query collections of suitably indexed data. The data is displayed via a browser. One drawback to these sources is that there is no standard programming interface suitable for applications to(More)
Topic detection with large and noisy data collections such as social media must address both scalability and accuracy challenges. KeyGraph is an efficient method that improves on current solutions by considering keyword cooccurrence. We show that KeyGraph has similar accuracy when compared to state-of-the-art approaches on small, well-annotated collections,(More)
In this paper, we focus on finding complex annotation patterns representing novel and interesting hypotheses from gene annotation data. We define a generalization of the densest subgraph problem by adding an additional distance restriction (defined by a separate metric) to the nodes of the subgraph. We show that while this generalization makes the problem(More)
We consider Cooperative Information Systems (CIS) that are multidatabase systems (MDBMS), with a common object-oriented model, based on the ODMG standard, together with local databases that may be relational, object-oriented, or dedicated data servers. The MDBMS interface (or mediator interface) that describes this CIS could be diierent from the union of(More)
1 Scaling Access to Heterogeneous Data Sources with Disco DRAFT { NOT FOR DISTRIBUTION { SEE TKDE 1998 FOR FINAL VERSION Anthony Tomasic, Louiqa Raschid and Patrick Valduriez Abstract|Accessing many data sources aggravates problems for users of heterogeneous distributed databases. Database administrators must deal with fragile mediators, that is, mediators(More)
This paper describes a technique to support interoperable query processing when multiple heterogeneous knowledge servers are accessed. The problem is to support query transformation transparently, so a user can pose queries locally, without any need of global knowledge about diierent data models and schema. In a companion paper, an architecture for(More)
Abstract. The rapid growth of the Internet and support for interoperability protocols has increased the number of Web accessible sources, WebSources. Current wrapper mediator architectures need to be extended with a wrapper cost model (WCM) for WebSources that can estimate the response time (delays) to access sources as well as other relevant statistics.(More)