Daniela F. Brauner

Database Conceptual Schema Matching

A database conceptual schema is a high-level description of how database concepts are organized, which is typically as classes of objects and their attributes. A fundamental operation in many database applications, schema matching involves finding a mapping mu between the concepts in a source scheme S and the concepts in a target schema T such that, if t = mu(s), then s and t have the same meaning. Along with data warehousing, query mediation relies heavily on schema marching. This application uses a mediator to translate user queries, formulated in terms of a common schema M, into queries that local databases can handle. The mediator must therefore be able to match each local schema with M. Query mediation is particularly challenging in the context of the Web, where the number of local databases, over which the mediator has little control, is enormous. We examine three major approaches to schema matching - syntactic, semantic, and a priori - using examples, with a focus on mediator design.

Towards Gazetteer Integration through an Instance-based Thesauri Mapping Approach

A gazetteer is a database that stores information about a set of geographic features, classified using terms taken from a given feature type thesaurus. A geographic information system may integrate one or more gazetteers to create a consolidated information source about the data the system stores, for example [9]. However, as in a data-warehouse creation process, gazetteer integration requires aligning feature type thesauri, which is the central question we address in this paper.

Mediation as recommendation: an approach to design mediators for object catalogs

A catalog holds information about a set of objects, typically classified using terms taken from a given thesaurus Mediated access to a collection of catalogs over the same domain therefore requires some strategy to deal with multiple thesauri, which represent different classifications for the same domain This paper proposes an approach using online mapping rate estimations to define weighted relationships between terms of distinct thesauri The mediator then uses such relationships to remap keyword-based queries to the different catalogs Moreover, query answers provide valuable feedback to adjust the relationship weights, thereby improving the mediator accuracy.

Matching object catalogues

A catalogue holds information about a set of objects, typically classified using terms taken from a given thesaurus, and described with the help of a set of attributes. Matching a pair of catalogues means to find a relationship between the terms of their thesauri and a relationship between their attributes. This paper first introduces a matching approach, based on the notion of similarity, that applies to both thesauri and attribute matching. It then describes matchings based on mutual information and introduces variations that explore certain heuristics. Finally, it discusses experimental results that evaluate the precision of the matchings and that measure the influence of the heuristics.

Creating advanced Internet services in collaboration with the research community

We describe the experience of RNP, the Brazilian NREN, in creating advanced Internet services in partnership with the national research community in networks and distributed systems, how this model was later adopted with adaptations by the RedCLARA (Latin American regional network) community, and also some successful results in both of these domains. The RNP Working Groups programme was launched in 2002 with the objective of developing collaborative projects between RNP and research groups, to demonstrate the feasibility of using new network protocols, services and applications. The development teams are called Working Groups (WGs), formed by a coordinator, who is usually a researcher in a public or private university or research institution, and a team of assistants. RNP staff members follow closely the activities of the WG. The WG concept has been adopted at RNP both for developing new end-user application service, and also for introducing new technologies into core areas such as security services, performance monitoring and dynamic provisioning of virtual circuit services, in order to accompany international trends to add such advanced features to the service offerings of research networks. The paper also describes related work in theRedCLARA community to coordinate development activities carried out by Latin American NRENs, to establish working groups to study and propose new services for RedCLARA.