Semantic Technologies

In recent years the Semantic Web has emerged as one of the most essential achievements for the future of the World Wide Web (WWW). Semantic Web technology extends the WWW but also enables to improve applications which are related to other fields such as communication, information, knowledge, media, and interaction technologies. Semantic Web provides not just new technologies and tools but also new paradigms and ways of thinking, to make information processing more efficient and more structured.

Our research is focussed on the devolpment and improvement of 'semantically supported multimedia retrieval and search technologies'.

Table of Contents

  • Current News
  • Prior Events and Activities
  • Research Topics
  • Research Team
  • Former Team Members
  • Teaching
  • Supervised Master Theses
  • Projects and Partners
  • In the Media
  • Recent Publications

Research Topics

  • (1) Semantic Multimedia
  • (2) Linked Data Engineering and Applications
  • (3) Semantically enhanced Information Retrieval (Semantic Search)
  • (4) Knowledge Mining and Ontological Engineering
  • (5) Semantically enriched e-Learning Applications

Job Offers

Research Team

Former Team Members

  • Dipl.-Inf. Katarina Birghan
  • Tamara Bobic, M.Sc.
  • Dipl.-Dokumentar Johannes Hercher
  • Dipl.-Inf. Zalan Kramer
  • Johannes Osterhoff, M.A.
  • Bernhard Quehl, M.Sc.
  • Dr. Nadine Steinmetz
  • Dipl.-Inf. Lina Wolf
  • Dipl.-Ing. Haojin Yang
  • Joscha Jäger, M.A. (internship)

Our group

Left to Right: Nadine Steinmetz, Johannes Osterhoff, Dr. Harald Sack, Jörg Waitelonis, Christian Hentschel, Bernhard Quehl


 ...  2008  2009  2010  2011  2012  ...     Advanced Search

Semantische Suche - Theorie und Praxis am Beispiel der Videosuchmaschine

Harald Sack
Web 3.0 & Semantic Web, HMD - Praxis der Wirtschaftsinformatik, vol. 271 2010
Contributions to Proceedings:

The Path is the Destination – Enabling a New Search Paradigm with Linked Data

Jörg Waitelonis, Magnus Knuth, Lina Wolf, Johannes Hercher, Harald Sack
In Proceedings of the Workshop on Linked Data in the Future Internet at the Future Internet Assembly (LDFI 2010), volume 700 of CEUR Workshop Proceedings, Ghent, Belgium, 12 2010

Use What You Have – Yovisto Video Search Engine Takes a Semantic Turn

Jörg Waitelonis, Nadine Ludwig, Harald Sack
In Proceedings of the 5th International Conference on Semantic and Digital Media Technologies (SAMT 2010), Saarbrücken, Germany, 12 2010 to be published

Exploratory Semantic Video Search with yovisto

Jörg Waitelonis, Harald Sack
In Proceedings of the 4th IEEE International Conference on Semantic Computing (ICSC 2010), pages 446-447, Pittsburgh, PA, USA, 9 2010 IEEE Press.

Indexing German Audiovisual Heritage - SKOSification Made Easy

Johannes Hercher, Harald Sack
In Proceedings of the 9th European Workshop (in conjunction with the 14th ECDL) on Networked Knowledge Organization Systems/Services (NKOS 2010), Glasgow, Scottland, 9 2010

Semantically Enabled Exploratory Video Search

Jörg Waitelonis, Harald Sack, Zalan Kramer, Johannes Hercher
In Proceedings of the 3rd International Workshop (in conjunction with the 19th WWW) on Semantic Search (SemSearch 2010), pages 8:1-8:8, Raleigh, NC, USA, 4 2010 ACM Press.
 ...  2008  2009  2010  2011  2012  ... 

Projects and Partners


  • AV-Portal Gottfried-Leibnitz-Universität Hannover, project with Technische Informationsbibliothek Hannover (TIB)
  • Semantic Media Explorer (SEMEX)
    The Semantic Media Explorer is a demonstrator that combines the latest media analysis processes to provides optimal access to video content.
  • MEDIAGLOBE Project
    The aim of MEDIAGLOBE is to open and interlink heterogenouse and currently isolated information sources in media archives and broadcasting corporation. Project partners: DEFA-spektrum, Medienbildungsgesellschaft Babelsberg mbH, Blue Order GmbH
    The purpose of CONTENTUS is to develop basic technologies with which to access, archive and search for multi-media cultural assets and works of art.
    Yovisto is a video search engine specialized in academic content. Yovisto's search index is based on the combination of automated content based video analysis with user generated collaborative annotation (collaborative tagging, discussions, and comments). In difference to traditional video search engines, Yovisto enables pinpoint access within video data by providing fine-granular, time-dependent metadata.
  • Semantic Games
    Games with a purpose that are dedicated to create and curate semantic content.

Current News

Prior Events and Activities









2014 (SS)

2013/14 (WS)

2013 (SS)

  • Seminar (Master): Semantic Multimedia (Blog)
  • Seminar (Bachelor): Multimedia Analyse Technologien (Blog)
  • Schülerkolleg (für Schüler der 8. bis 10. Klasse): Internetsuche und Google PageRank - Wie wird was durch wen gefunden?

    • Woche 1 - 09.04.2013: Die Geschichte der Web-Suchmaschinen (pdf)
    • Woche 2 - 23.04.2013: Term- und Dokumentenranking (pdf)
    • Woche 3 - 07.05.2013: Google Page Rank (pdf)
    • Woche 4 - 21.05.2013: Personalisierung und Web Crawling (pdf)
    • Woche 5 - 04.06.2013: Semantische Suche



2012/13 (WS)

2012 (SS)

2011/12 (WS)

2011 (SS)

2010/11 (WS)

2010 (SS)

2009/10 (WS)




Supervised Master Theses

  • Gerald Töpper: Erweiterung der DBpedia Ontologie und des Extraction Frameworks zur Sicherung der Datenqualität. (finished April 2012)
  • Peter Retzlaff: Visualisierung von Bag-of-Visual-Words-Vektoren für die Visual Concept Detection (finished March 2014)
  • Sebastian Stange: Evaluierung einer semantischen Videosuche und Ermittlung geeigneter Videoanalysetechniken (finished March 2014)
  • Michael Wolowyk: Semantic Recommender Systems (preliminary title) (in progress)

Open Master Theses

Please find a list of possible topics for Master Theses. Contact us, if you are interested in one of these topics or have own suggestions.

  • Video Analysis:

    • OCR Spellcorrection
    • Tag Relevance Estimation in Photo Communities
    • Learning Local Image Descriptors

  • Linked Data and Semantic Web:

    • Named Entity Evolution
    • Authority File Mapping
    • A Mereology for Media Fragments






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