Semantic Web

Winter 2015/2016
Wiltrud Kessler
Monday 15:45 - 17:15
Pfaffenwaldring 5b, V 5.01
2 SWS / 3 ECTS
[LSF] [ILIAS]

News

• [2.3.16] The exam has been graded. If you want to have a look at it, come by my office next Tuesday between 2 and 3 PM.
• [25.1.16] The miniproject deadline has been moved to Friday February 5th, 22:59. The deadline for exercise sheet 3 stays at Wednesday January 27th, 23:59.
• [12.1.16] The date and time for the exam have been fixed: Tuesday 23rd of February, 11 AM (practice exam on 16th, also 11 AM).
• [12.1.16] I have uploaded a slightly corrected version of the SPARQL slides (deleted one empty entry in the result table for the FILTER example that shouldn't be there).
• [23.11.15] There have been some errors in the Turtle syntax in slideset "2A Ontologies", I've uploaded a corrected version.
• [18.09.15] Course starts on October 19th.

Schedule and Resources

Resources (slides, examples and exercises) will be made available here. Please submit your solutions to the exercises in ILIAS.

Bring your computer to sessions marked project (P) or exercise/Uebung (U). Before the first project session, please install Protege Ontology Editor.

Day	Topic	Resources	Chapters	More references
Block 1 "Semantic Web Basics"
19.10. (V)	The Semantic Web Vision	Slides	[HKRS08] Ch.1 [HKR09] Ch.1	The Semantic Web (2001) The Semantic Web Revisited (2006) The Semantic Web in Action (2007) Application example: Relfinder
26.10. (V)	Semantic Web Basis Technologies	Slides pets.xml	[HKRS08] Ch.2 [HKR09] App.A	Unicode Code Charts XML Validator XML Schema data types
	Linking Data with RDF	Slides pets.rdf pets.ttl	[HKRS08] Ch.3 [HKR09] Ch.2	RDF format converter RDF Validator Visualization: LodLive
2.11. (V)	Light-weight Semantics with RDFS	Slides pets_rdfs.rdf pets_rdfs.ttl	[HKRS08] Ch.4 [HKR09] Ch.3
9.11. (P)	Project Session 1	Slides	[HKR09] Ch.8
16.11. (U)	Exercise Session 1 Deadline: Wednesday November 11th, 23:59	Sheet 1 Template for 1(a-c), 1(d)
Block 2 "Ontologies and Logic"
23.11. (V)	Ontologies and OWL	Slides pizza_small.ttl pizza_small.owl pizza.owl	[HKRS08] Ch.5 [HKR09] Ch.4	Visualiztion: VOWL
30.11. (V)	Reasoning	Slides	[HKRS08] Ch.6 [HKR09] Ch.5	Basic Description Logics
7.12. (P)	Project Session 2	Slides Slides	[HKR09] Ch.8	Protege Ontology Editor
14.12. (U)	Exercise Session 2 Deadline: Wednesday December 9th, 23:59	Sheet 2 Template Cheat sheet
Block 3 "The Upper Layers"
11.1. (V)	SPARQL	Slides	[HKRS08] Ch.7 [HKR09] Ch.7	DBPedia SPARQL web frontend
18.1. (V)	Semantic Web Agents	Slides		Artificial Intelligence: A Modern Approach (Ch. 2, 7) Agents and the Semantic Web (2001)
	Trust	Slides		Understanding Cryptography (Ch. 6, 7, 10) The Trust Project
25.1. (V + P)	Semantic Web Applications	Slides	[HKR09] Ch.9	RDFa recommendation CreativeCommons ontology FOAF GRDDL recommendation Geonames DBPedia LOD cloud Sindice GoPubMed Evi Broccoli
	Project Session 3 Miniproject deadline: Friday February 5th, 23:59			Twinkle
1.2. (U)	Exercise Session 3 Deadline: Wednesday January 27th, 23:59	Sheet 3 Template Cheat sheet
16.2. (Tue)	Practice Exam (Tuesday, 11 AM, ca. 60 min, V5.02)
23.2. (Tue)	Written Exam (Tuesday, 11 AM, ca. 60 min, V5.02)

The column "Chapters" refers to the chapters in the basic books (listed below) that discuss the class topic. It may be useful to read the corresponding chapter in one of the books to better understand the course content. More specific literature, links and tools for some topics can be found in the column "More references" and on my Semantic Web resources page. This is not required to pass the course, but may be interesting background reading for those interested. Additional links will be added during the course, also all the basic books contain a lot of references.

Additional slidesets on topics that we discussed in class ("muddiest point" explanations, leftovers from last years):

• Supplementary Material: Skills you will acquire or "what's the coolest thing I will learn"
• Supplementary Material: More about Namespaces (mostly with XML)
• Supplementary Material: More about RDF Properties
• Supplementary Material: Non-binary relations in RDF
• Supplementary Material: More about Inference with Tableaux
• Supplementary Material: Questions from exercise sheet 3

Additional slidesets on topics not discussed in class (leftovers from last years):

• Supplementary Material: XML
• Supplementary Material: XML Schema
• Supplementary Material: Tableaux Termination and Blocking
• Semantic Web and Natural Language Processing
• Semantic Search

Course Description

The Semantic Web is an initiative to make information in the web accessible to machines. In the first part of the course, basic concepts and technologies of the Semantic Web will be introduced (XML, RDF, RDFS). The second part focuses on ontologies, OWL for describing ontologies, ontology engineering, and reasoning with ontologies. In the third part, the query language SPARQL is intruduced and some applications and research topics inside the Semantic Web will be mentioned, e.g., semantic agents, semantic search or ontology learning. Apart from theoretical classes, the course will include practice sessions.

Basic text books (both cover basically parts 1 and 2 of this course):

• [HKRS08] Pascal Hitzler, Markus Krözsch, Sebastian Rudolph and York Sure. Semantic Web. Grundlagen. Springer textbook, 2008. ISBN 978-3-540-33993-9. (German, available in the library as an electronic book) [page]
• [HKR09] Pascal Hitzler, Markus Krözsch, Sebastian Rudolph. Foundations of Semantic Web Technologies. Chapman & Hall/CRC, 2009. ISBN 978-1-420-09050-5. (English, available in the library) [page]

There are no particular prerequesites. A basic understanding of predicate logic is helpful (to the extent that is taught in the basic class of logic in the first year of Diplom and Bachelor).

Organizational Information

The course is open for students of

• M.Sc. Computational Linguistics who can get credit for it as
  • module "Semantic Web" in the electives catalogue MCL 6 (3 LP, graded) [preferred option!!]
  • part of the concentration "Statistical Natural Language Processing" or the concentration "Semantics and Syntax" (together with other classes to give a total of 12 LP).
  • one of the modules "Computational Linguistics Breadth Module [A|B|C]" in the electives catalogue MCL 7 (3 LP, non-graded)
  • one of the modules "Applications of Statistical Natural Language Processing" or "Methods in Statistical Natural Language Processing" in the electives catalogue MCL 1 together with another 2 SWS/3 LP course. (6 LP, graded)
• B.Sc. Maschinelle Sprachverarbeitung as an elective in the "Wahlbereich F: Fortgeschrittene Themen der Maschinellen Sprachverarbeitung" as part of the module "Fortgeschrittene Methoden in der Maschinellen Sprachverarbeitung" together with another 2 SWS/3 LP course.
• Other computer-science related progams as an elective (depending on the program, we need to work out the specifics).

M.Sc. CL students who take the course as part of a concentration will have their exam as part of the oral exam for the concentration.
For all other students there will be a written exam of 60 minutes in the break after semester ends. The final grade for the course will be the grade you get in the exam.

This is a "V+PL" course. To get admitted to the exam, you will have to pass the "Vorleistung". Requirements to pass the "Vorleistung":

1. Get at least 50% of the points in the mandatory exercises (there will be 3 exercise sheets with a maximum of 20 points each).
2. Present at least one exercise in in one of the exercise sessions.
3. Hand in the mandatory part of the course miniproject.

Exam-related Information

The written exam will be similar to the exercises done in the practice sessions plus a few more theoretical questions. You will be provided with a "cheat sheet" in case you need to write RDF, OWL or SPARQL, so that you do not need to memorize namespace URLs or the exact spelling of owl:equivalentProperty. You can find some old exams on this page.

The oral exam for the concentration will basically include the same topics as the written exam, but with less focus on exact syntax and more about understanding.

What you should be able to do in the exam:

• Answer the question "what is the semantic web and how do we get there".
• Convert sentences in natural language to RDF/RDFS/OWL statements and write them down in Turtle syntax.
• Convert sentences in natural language to OWL statements and write them down in DL syntax.
• Explain the semantics behind all RDF/RDFS/OWL syntax elements discussed in class.
• Know the differences between RDF, RDFS and OWL.
• Explain the problem and the solution for non-binary relations in RDF/RDFS/OWL.
• List some ontology engineering issues and possible solutions.
• Understand how Tableaux works and what we want to do with it.
• Apply Tableaux to a knowledge base to see if it is satisfyable.
• Know how SPARQL works.
• Write SPARQL queries using all introduced language elements (UNION, OPTIONAL, FILTER).
• Have a general idea about what a Semantic Web agent is.
• Know what digital signatures and encryption are used for.

What I will not ask:

• Any specific dates, e.g., "when was the RDF recommendation finalized", people, namespaces, the sort of thing you look up.
• Details about Unicode, UTF-8, XMLSchema or full XML syntax.
• Elements of RDF/RDFS/OWL/SPARQL that we did not discuss in class.
• Questions about predicate logics not related to Tableaux.
• Specifics of public key cryptography, how to generate keys, etc.
• Specifics about agents in artificial intelligence, distributed systems or elsewhere.
• Specifics about the presented SW applications, search engines, Protege, etc.