Swoogle can be said to be a indexing and retrieval system for the Semantic Web documents like RDF or OWL document. It evaluate the documents that is discovered by it to assess useful metadata properties and relationships between them.
The Semantic Web, within the form of RDF and OWL documents, is basically a web universe parallel to the web of HTML documents. There’s up to now no standard way for HTML (even XHTML) documents to embed RDF and OWL markup or to reference them in a very standard way that carries meaning. Semantic Web documents reference each other similarly as HTML documents in meaningful ways. this case makes it appropriate to design and build specialized Internet search engines customized for Semantic Web Documents (SWDs).
The system is meant to assist human users and also software agents and services. At this stage, human users are expected to be semantic web researchers and developers who have an interest in accessing, exploring and querying a set of metadata representing a significant fraction of the RDF and OWL documents found on the online . Software APIs will support programs that require to find SWDs matching certain descriptions, e.g., those containing certain terms, almost like other SWDs, using certain classes or properties, etc.
Swoogle architecture
Swoogle’s architecture have four major components such SWD discovery, metadata creation, data analysis, and interface. The architecture is data centric and extensible( i.e., different components work on different tasks independently).
- SWD discovery component: responsible to discover the potential SWDs throughout the Web and keep up-todate information about SWDs.
- Metadata creation component: caches a snapshot of a SWD and generates objective metadata about SWDs in both syntax level and semantic level.
- Data analysis component: uses the cached SWDs and the created metadata to derive analytical reports, such as classification of SWO and SWDB, rank of SWDs, and the IR index of SWDs.
- Interface component: focuses on providing data service to the Semantic Web community.
Features of Swoogle
A general user can query with keywords, and the SWDs matching those keywords are returned in ranked order. It is observed that the ranking algorithm ranks SWOs higher than SWDBs; thus, SWOs using those query terms will be returned before SWDBs using those terms.
The highest ranked SWDs typically are the base ontologies that define the semantic web languages, such as the RDF or OWL definitions, which all SWDs must import.
For advanced users, an “advanced” search interface is provided, which essentially allows them to fill in the constraints to a general SQL query on the underlying database.
The user can query using keywords, content based constraints , language and encoding based constraints , and/or the Rank of the document.
