184.729 Semantic Technologies
This course is in all assigned curricula part of the STEOP.
This course is in at least 1 assigned curriculum part of the STEOP.

2024S, VU, 2.0h, 3.0EC, to be held in blocked form
TUWEL

Properties

  • Semester hours: 2.0
  • Credits: 3.0
  • Type: VU Lecture and Exercise
  • Format: Online

Learning outcomes

After successful completion of the course, students are able to: 

(1)  Write domain specifications in RDF-S, SHACL, and in the OWL profiles. 

(2) Given such a specification and a knowledge graph, choose a suitable validation or inference algorithm, and mention an existing engine for the task at hand.  For example inputs of moderate size, the student will be able to perform the validation manually on paper. 

(3) Compare the semantics of partial-closed formalisms like SHACL with that of open-world  formalisms like OWL, and explain the consequences of these different semantic assumptions, both in terms of the resulting inference regimes, as in terms of the cost of testing entailment and evaluation. 

(4) Explain the basic algorithms for evaluating SPARQL queries (in well-formed monotone  SPARQL fragments) over knowledge graphs. 

(5) Given an inconsistent knowledge graph, list its repairs and compute the answers to a given query over standard variations of the repair semantics. 

(6) Given a description of a domain and of some possibly heterogenous incomplete data sources, write an OBDA specification to construct a virtual knowledge graph. 

(7) Given a query and an OBDA specification, explain how to compute the answers over the represented virtual knowledge graphs.  

 

Subject of course

The course studies several semantic technologies and the way they can be used for integrating and accessing data, especially data that cannot be easily handled with legacy techniques because it may be incomplete, inconsistent, or heterogeneous, and expensive to integrate and maintain.

We will study specification languages like RDF-S, SHACL, and the OWL profiles, as well as the SPARQL query language. These formalisms are studied in some detail, comparing their abstract syntax, their semantic assumptions, and their core algorithms for validation and query evaluation. We will see how RDF-S, SHACL, and OWL can be used to validate graph data, and to obtain useful knowledge graphs from data that may be incomplete and heterogeneous. We will study how these graphs can be queried in (fragments of) the SPARQL query language,  some of the algorithmic and computational challenges that result from different choices of formalisms, and solutions for querying both virtual and inconsistent knowledge graphs. 


Detailed contents: 

(1) Specification languages for graph data semi-structured data: RDF-S, SHACL, OWL profiles

- Abstract syntax of the formalisms

- Semantics, with emphasis on assumptions about data (in)completeness


(2) Validation and inference in knowledge graphs

- Validation and inference tasks

- Algorithms for validation and inference

- Detecting and repairing inconsistencies in data

- The computational cost of validation and inference in the different formalisms


(3) Querying knowledge graphs

- Foundations of SPARQL and fragments 

- Query evaluation in graphs with knowledge and inference


(4) Querying inconsistent knowledge graphs 

- Repairs, inconsistency tolerant query semantics 

- Algorithms and complexity


(5) Ontology-based data integration and access

- The OBDA paradigm and virtual knowledge graphs

- Query rewriting

- The OBDA pipeline

Teaching methods

The contents will be presented orally in the lectures, with support of blackboard and slides. 

Course work and exercises will be made available.

 

Mode of examination

Written

Additional information

ECTS breakdown: 3 ECTS = 75 hours

Lectures: 20 hours
Exercises and self-study:  53 hours
Exam: 2 hours

 

 

Lecturers

Institute

Course dates

DayTimeDateLocationDescription
Tue10:00 - 12:0012.03.2024 - 25.06.2024Seminarraum FAV EG B (Seminarraum von Neumann) Semantic Technologies lecture
Tue09:00 - 10:0016.04.2024 - 18.06.2024Seminarraum FAV EG B (Seminarraum von Neumann) Semantic Technologies - exercises,.
Semantic Technologies - Single appointments
DayDateTimeLocationDescription
Tue12.03.202410:00 - 12:00Seminarraum FAV EG B (Seminarraum von Neumann) Semantic Technologies lecture
Tue19.03.202410:00 - 12:00Seminarraum FAV EG B (Seminarraum von Neumann) Semantic Technologies lecture
Tue16.04.202409:00 - 10:00Seminarraum FAV EG B (Seminarraum von Neumann) Semantic Technologies - exercises,.
Tue16.04.202410:00 - 12:00Seminarraum FAV EG B (Seminarraum von Neumann) Semantic Technologies lecture
Tue23.04.202409:00 - 10:00Seminarraum FAV EG B (Seminarraum von Neumann) Semantic Technologies - exercises,.
Tue23.04.202410:00 - 12:00Seminarraum FAV EG B (Seminarraum von Neumann) Semantic Technologies lecture
Tue30.04.202409:00 - 10:00Seminarraum FAV EG B (Seminarraum von Neumann) Semantic Technologies - exercises,.
Tue30.04.202410:00 - 12:00Seminarraum FAV EG B (Seminarraum von Neumann) Semantic Technologies lecture
Tue14.05.202409:00 - 10:00Seminarraum FAV EG B (Seminarraum von Neumann) Semantic Technologies - exercises,.
Tue14.05.202410:00 - 12:00Seminarraum FAV EG B (Seminarraum von Neumann) Semantic Technologies lecture
Tue28.05.202409:00 - 10:00Seminarraum FAV EG B (Seminarraum von Neumann) Semantic Technologies - exercises,.
Tue28.05.202410:00 - 12:00Seminarraum FAV EG B (Seminarraum von Neumann) Semantic Technologies lecture
Tue04.06.202409:00 - 10:00Seminarraum FAV EG B (Seminarraum von Neumann) Semantic Technologies - exercises,.
Tue04.06.202410:00 - 12:00Seminarraum FAV EG B (Seminarraum von Neumann) Semantic Technologies lecture
Tue11.06.202409:00 - 10:00Seminarraum FAV EG B (Seminarraum von Neumann) Semantic Technologies - exercises,.
Tue11.06.202410:00 - 12:00Seminarraum FAV EG B (Seminarraum von Neumann) Semantic Technologies lecture
Tue18.06.202409:00 - 10:00Seminarraum FAV EG B (Seminarraum von Neumann) Semantic Technologies - exercises,.
Tue18.06.202410:00 - 12:00Seminarraum FAV EG B (Seminarraum von Neumann) Semantic Technologies lecture
Tue25.06.202410:00 - 12:00Seminarraum FAV EG B (Seminarraum von Neumann) Semantic Technologies lecture
Course is held blocked

Examination modalities

There will be a written exam at the end of the semester.  

Exams

DayTimeDateRoomMode of examinationApplication timeApplication modeExam
Thu - 03.10.2024written&oral13.09.2024 16:00 - 02.10.2024 23:00TISSSecond exam
Tue - 21.01.2025written14.01.2025 08:00 - 20.01.2025 12:00unknownFinal exam

Course registration

Begin End Deregistration end
18.02.2024 14:00 10.04.2024 13:00 01.05.2024 23:00

Registration modalities

Registration is required.

Curricula

Study CodeObligationSemesterPrecon.Info
066 645 Data Science Not specified
066 926 Business Informatics Mandatory elective
066 931 Logic and Computation Mandatory elective

Literature

No lecture notes are available.

Preceding courses

Miscellaneous

  • Attendance Required!

Language

English