1. n Joining the Semantic Web: a Practical Guide. Pasqualino “Titto” Assini Nesstar Ltd - UK

2. Nesstar - Networked Social Science Tools and Resources n nesstar NESSTAR : The “Data Web” The Data Web is the application of Semantic Web techniques and principles to the problem of statistical data and metadata (surveys, opinions polls) dissemination and processing.

3. Nesstar - Networked Social Science Tools and Resources n nesstar Joining the Semantic Web in A Few Easy(?) Steps Know What You Want To Say  Modelling Then Say It -> Map the Model to a Semantic Web Language Think of the Future  Managing Change Let Everybody Know  Publishing on the Semantic Web Make Your Entities Behave  Specifying Operations/Services

4. Nesstar - Networked Social Science Tools and Resources n nesstar Additional Considerations Keep it Simple Or Else  Why Being Too Clever Doesn’t Work on the Internet. XML – Friend or Foe of the Semantic Web?

5. Nesstar - Networked Social Science Tools and Resources n nesstar Know What You Want To Say The Semantic Web is no silver bullet. It won’t help you in modelling your data. Use your existing modelling language (and models). You can also use RDF/RDF Schema but: –Not many (graphical tools) tools –Not much expressive power (example: no relationships) Tip: Use standard UML design tools (in most cases a UML Class Diagram is all you need)

6. Nesstar - Networked Social Science Tools and Resources n nesstar Now Say It Once you have you model you need to translate it to a Semantic Web Language: –Choose the target language: RDF, WOL –Define the mapping rules (might be already defined, UML  RDF) What about using a specialised XML syntax? –Advantage: More compact/simpler syntax –Disadvantage: Difficult to design properly, need to define an additional mapping to RDF. Tip: Stick to standard RDF syntax.

7. Nesstar - Networked Social Science Tools and Resources n nesstar Managing Change Fact of Life: things change, models do as well. Specific Application/Clients will need to extend your core model. Good News: RDF was custom made to be extensible (class/property inheritance, additional properties, reification) Tip: Make sure that your applications can handle model extensions.

8. Nesstar - Networked Social Science Tools and Resources n nesstar Publishing on the Semantic Web Wrong assumption: You need something special, a Registry maybe (e.g, UDDI) This can be real easy, just do it the WWW way. Self-description principle: objects and types self-describe themselves by making accessible, via HTTP, their RDF description at their URL.

9. Nesstar - Networked Social Science Tools and Resources n nesstar Specifying Specifying Behaviour Example: Bank Account operations to pay in or draw money. The Semantic Web is silent on this point. Major oversight  Web Services come to the rescue. Problem: Web Services and the Semantic Web are not well integrated (but we might soon have an RDF model of WSDL). Can’t wait? Use what is available: DAML-S, NEOOM (simple RDF model of methods plus method invocation via HTML FORMs).

10. Nesstar - Networked Social Science Tools and Resources n nesstar Keep It Simple or Else Fact: The value of an information dissemination system depends on the quantity of information it contains and the number of eyeballs looking at it. Therefore: initially the system is worthless (the Web was, the Semantic Web still is). But, if it starts growing it can grow real fast. So: how do you get the snowball going? KISS to lure early adopters.

11. Nesstar - Networked Social Science Tools and Resources n nesstar XML - Friend of Foe ? (RDF/)XML is very hard to write by hand and not particularly pleasant to read. It would be very useful if people (early adopters) could jot down semantic web descriptions without tools (think of HTML). TBL has lately engaged in an unofficial and very politically incorrect activity: defining a non-XML syntax for RDF: N3. What about an official W3C initiative to create a semantic web language that is not only machine understandable but also easy for an human to read and write?