Open Data Initiatives at HPI

This page gathers open-data-related activities at HPI, in particular in the area of linked open data and the semantic web. Contributing groups are

Internet technologies and systems (Christoph Meinel and Harald Sack)
Information systems (Felix Naumann)

Research Projects

GovWILD
GovWILD gathers and integrates government data from diverse government data sources, presents them in a Web interface and provides the data for download.
Received the IBM Scalable Data Analytics Award
ProLOD
Profiler for Linked Open Data (ProLOD) is a Web-based tool to perform data profiling tasks on datasets such as DBpedia. (NTII 2010 paper)
Yovisto
Yovisto is a semantic 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) and Linked Open Data resources such as DBpedia. In difference to traditional video search engines, Yovisto enables pinpoint access within video data by providing fine-granular, time-dependent semantic metadata being published as Linked Open Data (SAMT 2010 paper / SemSearch 2010 paper).
Mediaglobe
Cultural Memory provides an ever-increasing amount of information. Only a negligible small portion of this content is already accessable in the World Wide Web. Mediaglobe is a funded by the Federal Ministry of Economics and Technology within the context of the THESEUS research program 'New technologies for the internet of services' and aims to take media archives into the digital future providing availability and usability for the growing stock of audiovisual documents concerning German contemporary history. Mediaglobe offers state-of-the-art services for multimedia analysis and semantic multimedia search based on mappings to Linked Open Data resources on the web.
Stratosphere
The DFG Research Unit (Forschergruppe) is developing a cloud-based data management system. One of the use cases is to query and cleanse linked open data.
iPopulator
With iPopulator, we have introduced a system that automatically populates infoboxes of Wikipedia articles by extracting attribute values from the article's text. In contrast to prior work, iPopulator detects and exploits the structure of attribute values to independently extract value parts. We have published a set of extracted facts from Wikipedia. (CIKM 2010 paper / technical report)

Data Sets

GovWILD data set (JSON, SQL, RDF)
iPopulator: Extracted facts from Wikipedia (CSV, N3)

Publications

Langer, P. et al., 2014. Assigning Global Relevance Scores to DBpedia Facts. InInternational Workshop on Data Engineering meets the Semantic Web (DESWeb).Chicago, IL.
[ BibTeX ]

@inproceedings{rankfacts_dewsweb_2014, address = {Chicago, IL}, author = {Langer, Philipp and Schulze, Patrick and George, Stefan and Kohnen, Matthias and Metzke, Tobias and Abedjan, Ziawasch and Kasneci, Gjergji}, booktitle = {International Workshop on Data Engineering meets the Semantic Web (DESWeb)}, keywords = {LOD hpi isg}, title = {Assigning Global Relevance Scores to DBpedia Facts}, year = 2014 }
Abedjan, Z. et al., 2014. Profiling and Mining RDF Data with ProLOD++. InProceedings of the IEEE International Conference on Data Engineering (ICDE), Demo.Chicago, IL.
[ BibTeX ]

@inproceedings{prolodplusplus_icde_2014, address = {Chicago, IL}, author = {Abedjan, Ziawasch and Gruetze, Toni and Jentzsch, Anja and Naumann, Felix}, booktitle = {Proceedings of the IEEE International Conference on Data Engineering (ICDE), Demo}, keywords = {hpi lod rdfmining profiling isg}, title = {Profiling and Mining RDF Data with ProLOD++}, year = 2014 }
Abedjan, Z. & Naumann, F., 2014. Amending RDF Entities with New Facts. InKnow@LOD Workshop in conjunction with ESWC.Creete, Greece.
[ BibTeX ]

@inproceedings{abedjan_knowatlod_2014, address = {Creete, Greece}, author = {Abedjan, Ziawasch and Naumann, Felix}, booktitle = {Know@LOD Workshop in conjunction with ESWC}, keywords = {hpi lod rdfmining isg}, note = {Selected for Best Workshop Paper Award.}, title = {Amending RDF Entities with New Facts}, year = 2014 }
Lorey, J. & Naumann, F., 2013. Detecting SPARQL Query Templates for Data Prefetching. InProceedings of the 10th Extended Semantic Web Conference (ESWC).Montpellier, France.
[ BibTeX ]

@inproceedings{Johannes2013a, abstract = {Publicly available Linked Data repositories provide a multitude of information. By utilizing SPARQL, Web sites and services can consume this data and present it in a user-friendly form, e.g., in mash-ups. To gather RDF triples for this task, machine agents typically issue similarly structured queries with recurring patterns against the SPARQL endpoint. These queries usually differ only in a small number of individual triple pattern parts, such as resource labels or literals in objects. We present an approach to detect such recurring patterns in queries and introduce the notion of query templates, which represent clusters of similar queries exhibiting these recurrences. We describe a matching algorithm to extract query templates and illustrate the benefits of prefetching data by utilizing these templates. Finally, we comment on the applicability of our approach using results from real-world SPARQL query logs.}, address = {Montpellier, France}, author = {Lorey, Johannes and Naumann, Felix}, booktitle = {Proceedings of the 10th Extended Semantic Web Conference (ESWC)}, keywords = {isg}, title = {Detecting SPARQL Query Templates for Data Prefetching}, year = 2013 }
Abedjan, Z. & Naumann, F., 2013. Synonym Analysis for Predicate Expansion. InProceedings of the Extended Semantic Web Conference (ESWC), Montpellier, France.
[ BibTeX ]

@inproceedings{Ziawasch2013a, author = {Abedjan, Ziawasch and Naumann, Felix}, booktitle = {Proceedings of the Extended Semantic Web Conference (ESWC), Montpellier, France}, keywords = {isg}, title = {Synonym Analysis for Predicate Expansion}, year = 2013 }
Lorey, J., 2013. SPARQL Endpoint Metrics for Quality-Aware Linked Data Consumption. InProceedings of the 15th International Conference on Information Integration and Web-based Applications & Services (iiWAS '13).Vienna, Austria.
[ BibTeX ]

@inproceedings{Johannes2013a, abstract = {In recent years, dozens of publicly accessible Linked Data repositories containing vast amounts of knowledge presented in the Resource Description Framework (RDF) format have been set up worldwide. By utilizing the SPARQL query language, users can consume, integrate, and present data from a federation of sources for different application scenarios. However, several challenges arise for distributed query processing across multiple SPARQL endpoints, such as devising suitable query optimization or result caching strategies. For implementing these techniques, one crucial aspect is determining appropriate endpoint features. In this work, we introduce several metrics that enable universal and fine-grained characterization of arbitrary Linked Data repositories. We present comprehensive approaches for deriving these metrics and validate them through extensive evaluation on real-world SPARQL endpoints. Finally, we discuss possible implications of our findings for data consumers.}, address = {Vienna, Austria}, author = {Lorey, Johannes}, booktitle = {Proceedings of the 15th International Conference on Information Integration and Web-based Applications & Services (iiWAS '13)}, keywords = {isg}, title = {SPARQL Endpoint Metrics for Quality-Aware Linked Data Consumption}, year = 2013 }
Abedjan, Z. & Naumann, F., 2013. Improving RDF Data through Association Rule Mining. Datenbank-Spektrum (Special Issue on RDF Data Management), 13(2), Bl 111--120.
[ BibTeX ]

@article{abedjan_naumann_dbs_2013, author = {Abedjan, Ziawasch and Naumann, Felix}, edition = {Special Issue on RDF Data Management}, journal = {Datenbank-Spektrum (Special Issue on RDF Data Management)}, keywords = {isg}, number = 2, pages = {111--120}, publisher = {Springer}, series = {Special Issue on RDF Data Management}, title = {Improving RDF Data through Association Rule Mining}, volume = 13, year = 2013 }
Lorey, J. & Naumann, F., 2013. Caching and Prefetching Strategies for SPARQL Queries. InProceedings of the 3rd International Workshop on Usage Analysis and the Web of Data (USEWOD).Montpellier, France.
[ BibTeX ]

@inproceedings{usewod2013, abstract = {Linked Data repositories offer a wealth of structured facts, useful for a wide array of application scenarios. However, retrieving this data using SPARQL queries yields a number of challenges, such as limited endpoint capabilities and availability, or high latency for connecting to it. To cope with these challenges, we argue that it is advantageous to cache data that is relevant for future information needs. However, instead of only retaining results of previously issued queries, we aim at retrieving data that is potentially interesting for subsequent requests in advance. To this end, we present different methods to modify the structure of a query so that the altered query can be used to retrieve additional related information. We evaluate these approaches by applying them to requests found in real-world SPARQL query logs.}, address = {Montpellier, France}, author = {Lorey, Johannes and Naumann, Felix}, booktitle = {Proceedings of the 3rd International Workshop on Usage Analysis and the Web of Data (USEWOD)}, keywords = {isg}, note = {Selected as Best Workshop Paper for publication in ESWC post-proceedings}, title = {Caching and Prefetching Strategies for SPARQL Queries}, year = 2013 }
Lorey, J., 2013. Storing and Provisioning Linked Data as a Service. InProceedings of the 10th Extended Semantic Web Conference (ESWC).Montpellier, France.
[ BibTeX ]

@inproceedings{Johannes2013a, abstract = {Linked Data offers novel opportunities for aggregating information about a wide range of topics and for a multitude of applications. While the technical specifications of Linked Data have been a major research undertaking for the last decade, there is still a lack of real-world data and applications exploiting this data. Partly, this is due to the fact that datasets remain isolated from one another and their integration is a non-trivial task. In this work, we argue for a Data-as-a-Service approach combining both warehousing and query federation to discover and consume Linked Data. We compare our work to state-of-the-art approaches for discovering, integrating, and consuming Linked Data. Moreover, we illustrate a number of challenges when combining warehousing with federation features, and highlight key aspects of our research.}, address = {Montpellier, France}, author = {Lorey, Johannes}, booktitle = {Proceedings of the 10th Extended Semantic Web Conference (ESWC)}, keywords = {isg}, title = {Storing and Provisioning Linked Data as a Service}, year = 2013 }
Lorey, J. & Naumann, F., 2013. Caching and Prefetching Strategies for SPARQL Queries. InESWC 2013 Satellite Events -- Revised Selected Papers.Montpellier, France.
[ BibTeX ]

@inproceedings{Johannes2013a, abstract = {Linked Data repositories offer a wealth of structured facts, useful for a wide array of application scenarios. However, retrieving this data using SPARQL queries yields a number of challenges, such as limited endpoint capabilities and availability, or high latency for connecting to it. To cope with these challenges, we argue that it is advantageous to cache data that is relevant for future information needs. However, instead of only retaining results of previously issued queries, we aim at retrieving data that is potentially interesting for subsequent requests in advance. To this end, we present different methods to modify the structure of a query so that the altered query can be used to retrieve additional related information. We evaluate these approaches by applying them to requests found in real-world SPARQL query logs.}, address = {Montpellier, France}, author = {Lorey, Johannes and Naumann, Felix}, booktitle = {ESWC 2013 Satellite Events -- Revised Selected Papers}, keywords = {isg}, title = {Caching and Prefetching Strategies for SPARQL Queries}, year = 2013 }
Böhm, C. et al., 2012. GovWILD: Integrating Open Government Data for Transparency (demo). InProceedings of the International World Wide Web Conference (WWW).Lyon, France.
[ BibTeX ]

@inproceedings{Christoph2012a, address = {Lyon, France}, author = {Böhm, Christoph and Freitag, Markus and Heise, Arvid and Lehmann, Claudia and Mascher, Andrina and Naumann, Felix and Hernandez, Mauricio and Ercegovac, Vuk and Haase, Peter}, booktitle = {Proceedings of the International World Wide Web Conference (WWW)}, keywords = {isg}, title = {GovWILD: Integrating Open Government Data for Transparency (demo)}, year = 2012 }
Abedjan, Z., Lorey, J. & Naumann, F., 2012. Reconciling Ontologies and the Web of Data. InProceedings of the 21st International Conference on Information and Knowledge Management (CIKM).Maui, Hawaii, USA, , Bll 1532-1536.
[ BibTeX ]

@inproceedings{Ziawasch2012a, address = {Maui, Hawaii, USA}, author = {Abedjan, Ziawasch and Lorey, Johannes and Naumann, Felix}, booktitle = {Proceedings of the 21st International Conference on Information and Knowledge Management (CIKM)}, keywords = {isg}, pages = {1532-1536}, title = {Reconciling Ontologies and the Web of Data}, year = 2012 }
Böhm, C., Kasneci, G. & Naumann, F., 2012. Latent Topics in Graph-Structured Data. InProceedings of the Conference on Information and Knowledge Management (CIKM).
[ BibTeX ]

@inproceedings{boehm-topics-2012, abstract = {Large amounts of graph-structured data are emerging from various avenues, ranging from natural and life sciences to so- cial and semantic web communities. We address the problem of discovering subgraphs of entities that reflect latent topics in graph-structured data. These topics are structured meta- information providing further insights into the data. The presented approach effectively detects such topics by exploit- ing only the structure of the underlying graph, thus avoiding the dependency on textual labels, which are a scarce asset in prevalent graph datasets. The viability of our approach is demonstrated in experiments on real-world datasets.}, author = {Böhm, Christoph and Kasneci, Gjergji and Naumann, Felix}, booktitle = {Proceedings of the Conference on Information and Knowledge Management (CIKM)}, keywords = {isg}, title = {Latent Topics in Graph-Structured Data}, year = 2012 }
Böhm, C. et al., 2012. LINDA: Distributed Web-of-Data-Scale Entity Matching. InProceedings of the International Conference on Information and Knowledge Management (CIKM), Maui, Hawaii.
[ BibTeX ]

@inproceedings{Christoph2012a, author = {Böhm, Christoph and de Melo, Gerard and Naumann, Felix and Weikum, Gerhard}, booktitle = {Proceedings of the International Conference on Information and Knowledge Management (CIKM), Maui, Hawaii}, keywords = {isg}, title = {LINDA: Distributed Web-of-Data-Scale Entity Matching}, year = 2012 }
Gruetze, T., Böhm, C. & Naumann, F., 2012. Holistic and Scalable Ontology Alignment for Linked Open Data. InProceedings of the 5th Linked Data on the Web (LDOW) Workshop at the 21th International World Wide Web Conference (WWW).Lyon, France.
[ BibTeX ]

@inproceedings{www_GruetzeBN2012, address = {Lyon, France}, author = {Gruetze, Toni and Böhm, Christoph and Naumann, Felix}, booktitle = {Proceedings of the 5th Linked Data on the Web (LDOW) Workshop at the 21th International World Wide Web Conference (WWW)}, keywords = {isg}, month = 4, title = {Holistic and Scalable Ontology Alignment for Linked Open Data}, year = 2012 }
Abedjan, Z. & Naumann, F., 2011. Context and Target Configurations for Mining RDF Data. InInternational Workshop on Search & Mining Entity-Relationship Data (SMER), Glasgow, UK.
[ BibTeX ]

@inproceedings{abedjan_rdf_mining_2011, author = {Abedjan, Ziawasch and Naumann, Felix}, booktitle = {International Workshop on Search & Mining Entity-Relationship Data (SMER), Glasgow, UK}, keywords = {isg}, title = {Context and Target Configurations for Mining RDF Data}, year = 2011 }
Lorey, J. et al., 2011. RDF Ontology (Re-)Engineering through Large-scale Data Mining. InBillion Triples Challenge (BTC) at the 10th International Semantic Web Conference (ISWC).Koblenz, Germany.
[ BibTeX ]

@inproceedings{btc2011, address = {Koblenz, Germany}, author = {Lorey, Johannes and Abedjan, Ziawasch and Naumann, Felix and Böhm, Christoph}, booktitle = {Billion Triples Challenge (BTC) at the 10th International Semantic Web Conference (ISWC)}, keywords = {isg}, note = {Finalist}, title = {RDF Ontology (Re-)Engineering through Large-scale Data Mining}, year = 2011 }
Böhm, C., Lorey, J. & Naumann, F., 2011. Creating voiD Descriptions for Web-scale Data. Journal of Web Semantics: Science, Services and Agents on the World Wide Web, 9(3), Bll 339-345.
[ BibTeX ]

@article{voidJWS, author = {Böhm, Christoph and Lorey, Johannes and Naumann, Felix}, journal = {Journal of Web Semantics: Science, Services and Agents on the World Wide Web}, keywords = {Cloud_Computing RDF_Metadata_Generation Semantic_Web Vocabulary_of_Interlinked_Data isg Semantic_Data_Profiling}, number = 3, pages = {339-345}, title = {Creating voiD Descriptions for Web-scale Data}, volume = 9, year = 2011 }
Böhm, C. et al., 2010. Profiling linked open data with ProLOD. InWorkshops Proceedings of the 26th International Conference on Data Engineering (ICDE), Long Beach, CA., , Bll 175-178.
[ BibTeX ]

@inproceedings{conf_icde_BohmNAFGHPS10, author = {Böhm, Christoph and Naumann, Felix and Abedjan, Ziawasch and Fenz, Dandy and Gruetze, Toni and Hefenbrock, Daniel and Pohl, Matthias and Sonnabend, David}, booktitle = {Workshops Proceedings of the 26th International Conference on Data Engineering (ICDE), Long Beach, CA}, keywords = {isg}, pages = {175-178}, title = {Profiling linked open data with ProLOD}, year = 2010 }
Böhm, C. et al., 2010. Linking open government data: what journalists wish they had known. InProceedings the 6th International Conference on Semantic Systems (I-SEMANTICS), Graz, Austria. Available at: http://portal.acm.org/citation.cfm?id=1839751.
[ BibTeX ]

@inproceedings{conf_i-semantics_BohmNFGHKLMS10, author = {Böhm, Christoph and Naumann, Felix and Freitag, Markus and George, Stefan and Höfler, Norman and Köppelmann, Martin and Lehmann, Claudia and Mascher, Andrina and Schmidt, Tobias}, booktitle = {Proceedings the 6th International Conference on Semantic Systems (I-SEMANTICS), Graz, Austria}, keywords = {isg}, title = {Linking open government data: what journalists wish they had known}, year = 2010 }
Lange, D., Böhm, C. & Naumann, F., 2010. Extracting structured information from Wikipedia articles to populate infoboxes, Hasso-Plattner-Institut für Softwaresystemtechnik an der Universität Potsdam.
[ BibTeX ]

@techreport{techrep_iPopulator_2010, author = {Lange, Dustin and Böhm, Christoph and Naumann, Felix}, institution = {Hasso-Plattner-Institut für Softwaresystemtechnik an der Universität Potsdam}, keywords = {isg}, note = {ISBN 978-3-86956-081-6, ISSN 1613-5652}, number = 38, title = {Extracting structured information from Wikipedia articles to populate infoboxes}, year = 2010 }
Böhm, C. et al., 2010. Creating voiD Descriptions for Web-Scale Data. InBillion Triples Challenge (BTC) at the 9th International Semantic Web Conference (ISWC).Shanghai, China.
[ BibTeX ]

@inproceedings{Boehm10b, address = {Shanghai, China}, author = {Böhm, Christoph and Lorey, Johannes and Fenz, Dandy and Kny, Eyk and Pohl, Matthias and Naumann, Felix}, booktitle = {Billion Triples Challenge (BTC) at the 9th International Semantic Web Conference (ISWC)}, keywords = {isg}, note = {Winner}, title = {Creating voiD Descriptions for Web-Scale Data}, year = 2010 }
Lange, D., Böhm, C. & Naumann, F., 2010. Extracting structured information from Wikipedia articles to populate infoboxes. InProceedings of the 19th ACM Conference on Information and Knowledge Management (CIKM).Toronto, Canada, , Bll 1661-1664.
[ BibTeX ]

@inproceedings{conf_cikm_LangeBN10, address = {Toronto, Canada}, author = {Lange, Dustin and Böhm, Christoph and Naumann, Felix}, booktitle = {Proceedings of the 19th ACM Conference on Information and Knowledge Management (CIKM)}, keywords = {isg}, pages = {1661-1664}, title = {Extracting structured information from Wikipedia articles to populate infoboxes}, year = 2010 }
Böhm, C., Groth, P. & Leser, U., 2009. Graph-Based Ontology Construction from Heterogeneous Evidences. InProceedings of the International Semantic Web Conference (ISWC)., , Bll 91-96.
[ BibTeX ]

@inproceedings{iswc2009_boehm, author = {Böhm, Christoph and Groth, Philip and Leser, Ulf}, booktitle = {Proceedings of the International Semantic Web Conference (ISWC)}, keywords = {isg}, pages = {91-96}, title = {Graph-Based Ontology Construction from Heterogeneous Evidences}, year = 2009 }

Courses

Bachelor project: A Cloud Platform for On-Demand Access to Open Data
Master seminar: Large-Scale Data Analysis in the Cloud (see also Billion Triple Challenge 2010 paper and website)
Bachelor project: Midas: Extreme Web Data Integration for Government Data (see GovWILD project)
Master Seminar: Linked Data Profiling (see NTII 2010 paper)
Master Seminar: Large Scale Processing for Semantic Web Technologies (WS 2010/11)
Bachelor Seminar: Linked Open Data Application Engineering (WS 2009/10)
Master Seminar: Scalable Data Analysis Algorithms using DBpedia data sets (WS 2011/12)

Master's Theses

Learning to Extract Structured Information from Wikipedia Articles to Populate Infoboxes (Dustin Lange, 2009) (see also CIKM 2010 paper and tech report)
Wikipedia cross-lingual Concept Identification and Infobox Alignment (Daniel Rinser, 2010)
Strategies for structure-based rewriting of SPARQL queries for data prefetching (Armin Zamani, 2013)