Swoogle
Swoogle is simply a search engine for the semantic web. It was a project started by the research project of the Ebiquity Research Group in the Computer Science and Electrical Engineering Department at the University of Maryland, Baltimore County. From the perspective of Swoogle, the semantic web is a web of semantic web documents. And the Swoogle can be identified as a distributed online repository of semantic web documents. The main consideration of the Swoogle developers is to build a retrieval system to catch and organize already distributed semantic web documents systematically so that both human users and agents/tools can easily conduct searches and queries against this repository, it will greatly facilitate both ongoing Semantic Web and smart agent/tool development. So simply it is a crawler-based indexing and retrieval system for semantic web documents. In other words, Swoogle can be identified as a big indexation and retrieval system exclusively dedicated to SWDs.
As we all know in the ontology concept, we tried to maximize the reusability as much as possible. Because without ontology reuse, the original definition of the Semantic Web has been invalidated. With this root idea, we can express the major benefit of Swoogle. You use Swoogle to figure out whether there are already suitable ontologies within the underlying domain matching your need. To query the Swoogle engine, you can use specific terms, and Swoogle will tell you which are the current ontologies that still use the terms you mentioned. You should follow the link given by Swoogle at this stage and find out such ontologies to see how they match your desires. This is Swoogle’s most predominant usage.
Another usage of Swoogle is to Finding instance data. The semantic web aims to enable distributed data to be incorporated. But first, it is important to locate the data. A Swoogle user may ask for data about a specified class or a specified subject for all instance data. It is then necessary to load the triples of the returned SWDs into an information base for further querying.
Swoogle helps the users to study the semantic web structure. Structural information about the semantic web will be generated by the metadata computed by Swoogle. How related are they? What records refer to an ontology? What ontology is referred to in a document? What relationships occur between the two documents? We can find answers to these kinds of questions with Swoogle.
Next, we need to look at the basic architecture of Swoogle to have a broader idea about it. Simply, Swoogle is a crawler-based indexing and retrieval system for the Semantic Web. As seen in the figure below, the architecture of Swoogle can be split into four key components: (Li Ding, 2004) discovery of SWD, creation of metadata, analysis of data, and interface. This architecture is data-centric and extensible: different modules independently function on multiple tasks.
It is the responsibility of the SWD discovery component to discover new SWDs across the Web and maintain up-to-date SWD records. A snapshot of an SWD is cached by the metadata creation component and creates objective SWD metadata at both syntax and semantic levels. The cached SWDs and the generated metadata are used by the data analysis component to derive analytical reports, such as SWO and SWDB classification, SWD rank, and SWD IR index. The
the focus of the interface component is to provide the Semantic Web community with a data service.
Finally, as the conclusion of this article, For documents encoded in the semantic web languages RDF and OWL, existing web search engines such as Google and Yahoo don’t work well. This retrieval system is developed to function with natural languages and expect unstructured text consisting of words to contain documents. They do not understand protocols such as those surrounding XML namespace and do a bad job of tokenizing semantic web documents. Moreover, they do not understand and are therefore unable to take advantage of the systemic details encoded in the texts. To help them locate and interpret semantic web documentation on the web, semantic web researchers need search and retrieval systems today. as I discussed earlier the main intention of this Swoogle is to get advantages from the semantic web.