Ralf Schenkel Leader of the Junior Research Group "Efficient Search in Semistructured Data Spaces" within the Cluster of Excellence "Multimodal Computing and Interaction" Associated Senior Researcher at the Max-Planck-Institut für Informatik

Co-chair of the Efficiency Track at the Initiative for the Evaluation of XML Retrieval (INEX) and creator of the INEX 2009 annotated Wikipedia XML collection

Co-chair of the 2nd International Workshop on Modeling, Managing, and Mining of Evolving Social Networks (M3SN) (in conjunction with ICDE 2010), March 6, 2010, Long Beach, California, USA

Organizer of Herbstschule Information Retrieval 2010 of the GI-Fachgruppe Information Retrieval, September 26 - October 1, 2010, Schloß Dagstuhl, Germany

Leader of WP2 "Knowledge Layer" in the D-Grid project WisNetGrid, funded by the German Ministry of Education and Research (BMBF)

Job offer: We are searching for a PhD student or Postdoc for the WisNetGrid project (good knowledge of German required)

Current course:

Seminar "Social Networks" in Winter term 2009/2010 (with Sebastian Michel)

Recent previous courses:

• Specialized Lecture "Web Dynamics" in Summer term 2009 (with Marc Spaniol)
• Seminar "Probabilistic Databases" in Summer term 2009 (with Martin Theobald)
• Seminar "Techniques for Non-Traditional Data Management" (Winter term 2008, with Thomas Neumann)
• Basic course "Information Systems" (Summer term 2008, with Thomas Neumann)
• Seminar "Future of Web Search" (Winter term 2007, with Srikanta Bedathur)
  

See here for a more complete list of previous courses.

Topics for Master's and Bachelor theses available on request, see here for a list of completed theses that I (co-)supervised.

Research Interests:

• Efficient and Effective Search on Structured, Semistructured, and Unstructured Data
  
• Interactive Information Retrieval, especially Relevance Feedback for Text and XML
• Efficient Analysis, Mining and Retrieval in Social Networks
• Extraction, Mining, and Retrieval in Distributed Knowledge Sources
• Large-scale, Long-term Web Archiving

Summary of my recent research activities (PDF, 121K)

Selected Recent Publications:

• Shady Elbassuoni, Maya Ramanath, Ralf Schenkel, Marcin Sydow, and Gerhard Weikum: Language-model-based Ranking for Queries on RDF-Graphs. In: 18th ACM Conference on Information and Knowledge Management (CIKM 2009), Hongkong, China, 2009 .
• Michal Shmueli-Scheuer, Chen Li, Yosi Mass, Haggai Roitman, Ralf Schenkel, and Gerhard Weikum: Best Effort Top-K Query Processing Under Budgetary Constraints In: Proceedings of the 25th IEEE International Conference on Data Engineering (ICDE 2009), Shanghai, China, 2009.
• Thomas Neumann, Matthias Bender, Sebastian Michel, Ralf Schenkel, Peter Triantafillou, and Gerhard Weikum: Distributed Top-k aggregation queries at large In: Distributed and Parallel Databases 26 (1): 3-27, 2009.
• Avishek Anand, Srikanta Bedathur, Klaus Berberich, Ralf Schenkel, and Christos Tryfonopoulos: EverLast: A Distributed Architecture for Preserving the Web In: Proceedings of the Joint Conference on Digital Libraries (JCDL 2009), Austin, Texas, 2009.
• Ralf Schenkel, Tom Crecelius, Mouna Kacimi, Sebastian Michel, Thomas Neumann, Josiane Xavier Parreira, and Gerhard Weikum: Efficient Top-k Querying over Social-Tagging Networks In: Proceedings of the 31st Annual International ACM SIGIR Conference on Research & Development on Information Retrieval (SIGIR 2008), Singapore, Singapore, 2008.
• Martin Theobald, Holger Bast, Debapriyo Majumdar, Ralf Schenkel, and Gerhard Weikum: TopX: Efficient and Versatile Top-k Query Processing for Semistructured Data In: The VLDB Journal 17 (2): 81-115, 2008.
• Ralf Schenkel, Andreas Broschart, Seungwon Hwang, Martin Theobald, and Gerhard Weikum: Efficient Text Proximity Search In: 14th String Processing and Information Retrieval Symposium (SPIRE 2007), Santiago, Chile, 2007.

List of my publications (MPI publications server)

Summary of my dissertation

Selected Recent Program Committee memberships:

• 16th ACM SIGKDD Conference on Knowledge Discovery and Data Mining (KDD 2010), Washington, USA
• 36th International Conference on Very Large Data Bases (VLDB 2010), Core DB Track, Singapore
• 30th ACM SIGMOD International Conference on Management of Data, Indianapolis, USA
• 19th International World Wide Web Conference (WWW 2010), Search Track, Raleigh, USA
• 32nd European Conference on Information Retrieval (ECIR 2010), Milton Keynes, UK
• 27th International Conference on Data Engineering (ICDE 2010), Long Island, USA
• 3rd ACM International Conference on Web Search and Data Mining (WSDM 2010), New York City, USA
• 29th ACM SIGMOD International Conference on Management of Data, Demo Track, Rhode Island, USA
  
• 31st European Conference on Information Retrieval (ECIR 2009), Toulouse, France
• 25th International Conference on Data Engineering (ICDE 2009), Shanghai, China
• 31st Annual International ACM SIGIR Conference on Research & Development on Information Retrieval (SIGIR 2008), Singapore, R.O.C.
• 11th International Conference on Extending Database Technology (EDBT 2008), Nantes, France

Selected Talks:

• Efficient and Effective Search in Social Networks, Perspektivenvorlesung WS 2008/2009 (I have given similar talks at various other events)
• Efficiency Issues in Information Retrieval. Herbstschule der GI-Fachgruppe Information Retrieval, Schloß Dagstuhl, October 1, 2008.
• "IP" is not always "Internet Protocol". Dagstuhl Perspectives Workshop 08393 "Virtual games, interactive hosted services and user-generated content in Web 2.0", Schloß Dagstuhl, Germany, September 25, 2008.
• Efficient Top-k Querying over Social Tagging Networks. 31st Annual International ACM SIGIR Conference on Research & Development on Information Retrieval (SIGIR 2008), Singapore, July 23, 2008.
  
• Relevance Feedback in the TopX Search Engine. Dagstuhl Seminar 08111 "Ranked XML Querying", Schloß Dagstuhl, Germany, March 13, 2008.
• YAWN: A semantically annotated Wikipedia XML Corpus. 12th GI Conference on Databases in Business, Technology and Web (BTW 2007), Aachen, Germany, March 8th, 2007.
• Structural Feedback for Keyword-Based XML Retrieval. 28th European Conference on IR Research (ECIR 2006), London, UK, April 11th, 2006.
  
• Feedback-Driven Structural Query Expansion for Ranked Retrieval of XML Data. 10th International Conference on Extending Database Technology (EDBT 2006), Munich, Germany, March 28th, 2006.
• The SphereSearch Engine for Unified Ranked Retrieval of Heterogeneous XML and Web Documents . 31st International Conference on Very Large Data Bases (VLDB 2005), Trondheim, Norway, September 1st, 2005.
  
• Efficient Creation and Incremental Maintenance of the HOPI Index for Complex XML Document Collections. 21st International Conference on Data Engineering (ICDE 2005), Tokyo, Japan, April 6th, 2005.
  
• Integrating Snapshot Isolation Into Transactional Federations. Presented at 5th IFCIS International Conference on Cooperative Information Systems (CoopIS 2000), Eilat, Israel, September 6-8, 2000.
  

Office:

Other Activities:

• GI-Fachgruppe Information Retrieval
• THW-Jugend Saarland
  
• THW Spiesen-Elversberg (some general information in English)

Impressions from SIGMOD 2007 in Beijing (Nokia N95)
Impressions from EDBT 2004 in Heraklion (Canon G3)
Impressions from SSDBM 2004 on Santorini (Canon G3)