Catalog Services play a vital role on Data Grids by allowing users and applications to discover and locate the data needed. On large Data Grids, with hundreds of geographically distributed sites, centralized Catalog Services do not provide the required scalability, performance or fault-tolerance. In this article, we start by presenting and discussing the general requirements on Grid Catalogs of...

Based on the observation that graphs play an important role in the representation of databases, an algebra is presented for the manipulation of binary relations, i.e., of directed unlabeled graphs. This so-called Tarski algebra is based on early work by Tarski. The key notion that has been added to it here is tagging , which is needed for providing both enough modeling power and enough querying...

The design of an educational informatics system called EdUI, currently in development at the University of Idaho, is presented. Its purposes are to improve student retention and learning, and to facilitate efficient organization and presentation of learning resources. EdUI is essentially composed of a relational database of metadata describing and linked to learning objects. The use of open sou...

Provenance that captures e-Science activity has long term value only if the right amount and kind of information is collected. In this paper, we propose a two-layer model for representing provenance information capable of representing both execution information and higher level process details. The information model forms the basis for efficient relational database storage and query, and sets t...

Linguistic query systems are special purpose IR applications. We present a novel state-of-the-art approach for the efficient exploitation of very large linguistic corpora, combining the advantages of relational database management systems (RDBMS) with the functional MapReduce programming model. Our implementation uses the German DEREKO reference corpus with multi-layer linguistic annotations an...

Data warehousing is a booming industry with many inter esting research problems The database research community has concen trated on only a few aspects In this paper We summarize the state of the art suggest architectural extensions and identify research prob lems in the areas of warehouse modeling and design data cleansing and loading data refreshing and purging metadata management extensions ...

ion allows for comparatively naïve users and administrators, as the object store takes care of the detail of how and where user data is stored, protected, geo-replicated, deduplicated, versioned, garbage collected, and so forth. Abstraction also greatly simplifies application development and deployment, as evidenced by the plethora of start-ups, who are able to quickly get a worldwide service u...

For emulation and other preservation actions, metadata is needed to describe the technical environment (operating system, related software libraries, hardware etc.) in which a given file or item of software can be rendered. This paper delineates an enhanced entity attribute relationship model suitable as a basis for a database (relational, object-relational or object-oriented), or for a RDF ont...

This paper proposes an approach for translating an existing relational database (RDB) schema into relatively newer database (i.e., object-oriented, object-relational and XML) schemas, based on available standards. The approach is superior to existing proposals as it generates three different and equivalent target schemas. The solution takes an RDB as input, enriches its metadata representation ...