2012 – 2019: In addition to my work studies of computer science at the Open University in Hagen with a master’s degree. -2011 – today: Teacher in the faculty of computer science of the University of Applied Sciences in Saarbrücken, Germany (topics: programming with Java and C/C++, UML and the development of rich client applications based on Java with Swing, JavaFX, Hibernate and web applications based on JavaServer Pages, JavaServer Faces, Tapestry, Spring, SpringBoot, Vaadin and the portlet technology) – 2009 – 2010: Independant software developer and trainer – 2004 – 2010: Studies of Practical Computer Science at the University of Applied Sciences in Saarbrücken, Germany. – 2001 – 2004: vocational training for the occupation Fachinformatiker / Anwendungsentwicklung which means an application developer in Germany with Deutsche Telekom AG.
Java goes Semantic Web
This talk wants to present two techniques of the Semantic Web, RDF and OWL, and frameworks that allow the processing of semantic data in Java programs.
What is Semantic Web?
At the moment there are tries made to enhance the internet to the next level, often called Web 3.0. Nowadays, the internet only transports data instead of semantic information about them. When the user e.g. looks for the word “enterprise”, the search results can contain information about a company, an aircraft carrier, a space shuttle or a fictive starship. The information should be enriched by semantic data describing the information which can be interpreted by machines. This is called Semantic Web. There are several techniques to make the semantic information understandable for machines. Two of these techniques are the languages RDFS and OWL.
RDFS and OWL
The language RDFS (Resource Description Framework Schema) provides a vocabulary that allows the representation of a application domain. The resources in the domain, their properties and the relations between them can be described with the help of RDFS. A class based model allows to describe the domains in a semantic way. Such a vocabulary is also called an ontology. While RDFS makes the representation of simple ontologies possible, is the language OWL (Web Ontology Language) even more powerful, because OWL is based on description logic. Therefore an entire semantic concept can be described in a form that machines understand. Machines are able to check the ontology for logical and semantic errors and they are able to draw conclusions from the semantic information coded in the ontology.
Semantic Web with Java
The semantic information coded in an ontology with RDFS or OWL can be read and processed by applications written in the programming language Java by using some frameworks. RDF4J reads only data coded in RDF. The data are translated into Java objects and can be used in the application. Moreover RDF4J contains a so called triple store – a database for RDF data. More complex ontologies written in OWL can be read by the framework OwlAPI. OwlAPI also contains a reasoner that can infer the ontology.
The contents of the talk
Introduction of the basic concepts of Semantic Web
Introduction of the two languages RDFS and OWL with the help of some simple examples
Presentation of the two frameworks RDF4J and OwlAPI and simple programs that read the ontology files and process the semantic data