Semantic Search for Web Applications

Ontobroker comprises languages and tools that allow to semantically mark-up content
on web pages and let the user semantically query the WWW taking advantage of semantic
inferences. Ontobroker is based on the use of ontologies that guide the semantic
mark-up of web documents, the querying interface and that formulate semantic rules
for the domain. Thus, conventional web pages are augmented with a facility for
intelligent brokering services without requiring to change the semiformal nature of
web documents. Ontobroker has, e.g., been applied to needs of the knowledge
acquisition community. KA2 has been an initiative that provided semantic mark-up about
researchers, academic events, etc. such that ontobroker could be used for semantic
querying. Similar to Ontobroker the SHOE project intended to annotate web documents
with machine-readable knowledge. SHOE is a set of tools including a Knowledge
Annotator, the crawler Expose, the knowledge representation system PARKA, the PIQ
(Parka Interface for Queries) and SHOE Search.

The RDF Suite focuses on a suite of tools for RDF validation, storage and querying
based on object-relational database technology. Specifically, the authors introduce
a formal data model for RDF description bases created using multiple schemas.
Additionally, the design of a persistent RDF Store (RSSDB) for loading resource
descriptions in an ORDBMS by exploring the available RDF schema knowledge is
presented. Their work also includes the definition of RQL, a declarative language for
querying both RDF descriptions and schemas, and sketch query evaluation on top of
RSSDB. An example application using the RDFSuite has been applied to the domain of
cultural heritage.

In contrast to the systems mentioned above, within the GETESS (German Text
Exploitation and Search System) project, the idea of completely automatically generating
semantic markups has been pursued. For this purpose shallow natural language
text processing has been combined with ontologies to generate light-weight markups
for web pages. The automatically generated information has been collected and stored
in a database. Finally, a user interface (also natural language driven) offered access to
the semantically enriched web pages. The GETESS technology has been applied in
the tourism and finance domain. A detailed introduction into the GETESS project is
given in 1999.