Uni Göttingen
Institute for Informatics
Databases and Information Systems


Semantic Web
Winter 2006/07

Prof. Dr. Wolfgang May
Assistants: Erik Behrends, Oliver Fritzen, Franz Schenk

Date and Time: Monday, 14-16 ct, Friday 10-12 ct (every 2 weeks).
Lab (Übung): Friday 10-12 ct (every 2 weeks)
Room: MN67

Technical Data:
3+1 SWS, 6 ECTS credits (Studies in Applied Informatics),

Prerequisites: prospective participants should have attended the lecture Semistructured Data and XML.
Note: the "Modulkatalog" lists the module "Formal Systems" as prerequisite. "Formal Systems" will be introduced next year according to the new exam regulations. The WS0607 "Semantic Web" contains an introduction to logic at the beginning which replaces "Formal Systems" for now.
Note: the Modulkatalog lists "Semantic Web" with 4 ECTS CP. The WS0607 "Semantic Web" counts 6 CP since it additionally includes an introduction to formal logic.

Note: this is the first time that we give this course - thus all slides are preliminary and subject to change until the night before the lecture, and also afterwards.

Note: the module can be credited as "Applied Informatics". (Decision by the Dean of Studies on 25.10.2006). It is not associated with any Studienrichtung. For further aspects please prepare a personal plan of studies (that e.g. connects it with your application area etc.) and ask for approval by the DoS.

Course Description (preliminary)

  • Basic Notions of First-Order Logic (since they are not regularly taught in an earlier lecture)
  • RDF (updated from the Summer 2004 SSD&XML lecture)
  • RDFS, OWL: having RDF data with additional reasoning
  • Description Logics: the logic underlying OWL
  • Practical experiments with RDF, Jena, Reasoners etc.

Dates & Topics [Subject to Change]

  • 16.10.: No lecture. Instead, same time, same place: Information Meeting for first semester master students.
    The meeting will present the MSc studies according to the new exam regulations. Advanced BSc students are also invited to come.
  • 20.10.: Administrativa, Overview.
    Slides: Introduction and Ontologies [1-on-1, 2-on-1]
  • 23.10., 27.10.: No lecture. I am on travel.
  • 30.10.: Ontologies (Cont'd)
  • 3.11./6.11.: Introduction to first-order logic and basic notions of model theory.
    Slides: Introduction to Logics [1-on-1, 2-on-1]
  • 10.11. und 13.11.: keine Vorlesung wegen Dienstreise Rules and Rule Markup Languages for the Semantic Web.
  • 17.11.: Introduction to Logics (Cont'd)
  • 20.11.: Introduction to Logics (Cont'd)
  • 24.11.: keine Vorlesung wegen Dienstreise
  • Uebungsblatt: Logik
  • 27.11.: Introduction to Logics (Cont'd)
  • 1.12.: Introduction to Logics (Cont'd)
  • 4.12.: Besprechung des Logik-Uebungsblattes, dann weiter in der Vorlesung.
  • 8.12.: RDF
    Slides: RDF [1-on-1, 2-on-1]
    Note: all example files are accessible in the RDF subdirectory of this Web page.
  • 11.12.: RDF (Cont'd)
  • 15.12.: RDF (Cont'd)
  • 18.12.: RDF (Cont'd), RDFS
    Slides: RDFS [1-on-1, 2-on-1]
  • 22.12.2006: keine Vorlesung
  • 8.1.2007: keine Vorlesung
  • 12.1.: RDF/XML
    Slides: RDF/XML [1-on-1, 2-on-1]
  • 15.1.: RDF/XML (Cont'd)
    Folien RDF/XML: Aenderungen am 15.1. abends. Zu Folien 264/265: die beiden unterscheiden sich im wesentlichen in der Ueberschrift: Classes/Properties. Beide sind Zusammenfassungen wie und wo man diese URIs benutzt.
  • 19.1.: Description Logics
    Slides: DL [1-on-1, 2-on-1] (slides subject to change ...)
  • 22.1.: OWL 1.0
    Slides: OWL [1-on-1, 2-on-1] (updated Feb.1)
  • 26.1.: OWL (Cont'd)
  • 29.1.: OWL 1.1
    Slides: OWL 1.1 [1-on-1, 2-on-1] (updated Feb.1)
  • Slides updated on Feb 1st: mainly example programs (most of them work now) and final slides.
  • 2.2..: Finale: examples for DL tableaux, conclusion and outlook.
  • Exams: oral exams between 5.2.-9.2.2007
  • Die Meldung der Ergebnisse an Munopag erfolgt ... naechste Woche. Momentan ist das Pruefungsamt der Meinung, nach PO gaebe es nur ein Modul "Semantic Web" fuer 4 CP [die koennte aber sowieso nur diejenigen betreffen, die nach neuer PO Studieren] . Fuer dieses Modul konnte sich aber eigentlich niemand anmelden, da es "Formale Systeme" voraussetzt. Der Fall wird sich demnaechst klaeren. Prüfen Sie die CP-Eingaben im Munopag nach Eintragen der Ergebnisse nach.
    In der Zwischenzeit sollten Sie im Munopag mal pruefen, ob noch alle Kreditpunkte an Ort und Stelle sind. Der aktuelle Punkteschwund betrifft sicher das XML-Praktikum, wahrscheinlich aber auch das SQL-Praktikum und Datenbanken. Wer Punkte (ausser im XML-P, dort wird der Fall gerade geklaert) vermisst, soll sie bitte melden.
  • Ergebnisse der Vorlesungsevaluierung.
  • Wiederholungsprüfungen: zwischen 16.4. und 4.5. (Anmeldeschluss im Munopag 16.4.). Einzeltermine bitte per Mail ausmachen.

Some Links (preliminary, unordered)

Semantic Web Tools and Links

If you experience any problems (forgotten chmod, wrong paths, forgotten updates etc.), please notify us.

Web-wide Services

Datalog, F-Logic: Florid

  • the Florid Homepage (with some documentation) at Freiburg.
  • Mondial as Datalog facts: mondial-rel-facts.flp
  • Florid needs gcc4.x. It can be used in the CIP Pool only on computers running the most recent debian-etch distribution (this can be chosen when logging in; for use from remote, the computers c031-c034 run permanently under etch.).
    The executable is located at
    For using it, you also have to set paths
     export DEFAULTCFG="/afs/informatik.uni-goettingen.de/course/semweb-lecture/florid/environment/config.flp"
     export DEFAULTHIS="/afs/informatik.uni-goettingen.de/course/semweb-lecture/florid/environment/default.his" 
    Then you can start it, e.g. with the above input facts:
     > florid mondial-rel-facts.flp
       [...] Type 'sys.help.' for further information.
     ?- sys.eval.    // don't forget sys.eval.
                     // evaluates the facts and adds it to the knowledge base
     ?- country(A,B,C,D,E,F).
     // ... answers ...
     ?- sys.end.     // to leave it

Pellet - the OWL Reasoner

  • Pellet will be used mainly from the JENA tool.
  • Pellet Homepage (with Download)
  • For use in the CIP Pool, a Pellet instance running on ap34 can be used at http://ap34.ifi.informatik.uni-goettingen.de/pellet/.
  • If you have an own Pellet on your own computer, start it with ./pellet-dig.sh.
    Pellet usually runs at port 8081. The URL will then be http://localhost:8081.

Jena: RDF and SPARQL

The course uses a lightweight housemade shell interface to Jena for querying located at /afs/informatik.uni-goettingen.de/course/semweb-lecture/JENA-API/semweb.jar (Download; last updated 6.2.2007):

  • requires java 1.5
  • set alias (bashrc etc.)
     alias jena='java -jar /afs/informatik.uni-goettingen.de/course/semweb-lecture/JENA-API/semweb.jar'
  • query: (if=input-files, qf=query-file, e.g. in SPARQL)
    jena -q -if inputfiles -qf queryfile
  • general options:
    -il: input language (allows RDF/XML RDF/XML-ABBREV N-TRIPLE N3 TURTLE; N3 is default)
    -if: input files
  • query options:
    -q: query
    -il, -if: as above
    -qf: query-file
  • transform options:
    -t: transform
    -ol: output format (allows RDF/XML RDF/XML-ABBREV N-TRIPLE N3-PLAIN N3-PP N3-TRIPLE N3 TURTLE }; N3 is default)
  • export class tree; options:
    -e: export class tree (gives some insight for debugging an ontology ...)
    -il, -if: as above
  • reasoner options (for -q and -e):
    activate reasoning; default: internal reasoner: option -inf
    or use the pellet class that comes with the semweb.jar:
     jena -q -inf -r pellet -qf query-filename
    or short
     jena -q -pellet -qf query-filename
    or use an external reasoner: options -inf -r reasoner-url
    e.g. use the Pellet instance running at ap34 as external reasoner from the CIP Pool:
     jena -q -qf query-filename -inf -r http://ap34.ifi.informatik.uni-goettingen.de/pellet/ 

IsaViz: RDF Graph Visualizer

  • IsaViz is used for visualization of RDF-Graphs, installed locally at: /afs/informatik.uni-goettingen.de/course/semweb-lecture/tools/IsaViz/
  • You can either change into that directory and start the program with the command ./run.sh or by using an alias pointing to that script. In the latter case you will need to copy the configuration file isaviz.cfg into your home directory.
  • If you want to run the application on your own computer, you will have to install graphviz as well, either from its Web page or from the appropriate package provided by your distribution (e.g. debian-package graphviz).

Mondial in RDF (subject to change - updated 1.2.2007)