Olaf Hartig

According to our database, Olaf Hartig authored at least 93 papers between 2007 and 2024.

Collaborative distances:

• Dijkstra number of four.
• Erdős number of four.

2024

Ontology-based GraphQL server generation for data access and data integration.

Huanyu Li, Olaf Hartig, Rickard Armiento, Patrick Lambrix

Semantic Web, 2024

The materials design ontology.

Patrick Lambrix, Rickard Armiento, Huanyu Li, Olaf Hartig, Mina Abd Nikooie Pour, Ying Li

Semantic Web, 2024

Transforming Object-Centric Event Logs to Temporal Event Knowledge Graphs (Extended Version).

Shahrzad Khayatbashi, Olaf Hartig, Amin Jalali

CoRR, 2024

GRADES-NDA'24: 7th Joint Workshop on Graph Data Management Experiences & Systems (GRADES) and Network Data Analytics (NDA).

Olaf Hartig, Zoi Kaoudi

Proceedings of the Companion of the 2024 International Conference on Management of Data, 2024

The Open Circularity Platform: a Decentralized Data Sharing Platform for Circular Value Networks.

Gertjan De Mulder, Els de Vleeschauwer, Ben De Meester, Pieter Colpaert, Olaf Hartig

Proceedings of the The 2nd International Workshop on Knowledge Graphs for Sustainability (KG4S 2024) colocated with the 21st Extended Semantic Web Conference (ESWC 2024), 2024

2023

The OneGraph vision: Challenges of breaking the graph model lock-in.

Ora Lassila, Michael Schmidt, Olaf Hartig, Brad Bebee, Dave Bechberger, Willem Broekema, Ankesh Khandelwal, Kelvin Lawrence, Carlos-Manuel López-Enríquez, Ronak Sharda, Bryan B. Thompson

Semantic Web, 2023

Tutorials at The Web Conference 2023.

Valeria Fionda, Olaf Hartig, Reyhaneh Abdolazimi, Sihem Amer-Yahia, Hongzhi Chen, Xiao Chen, Peng Cui, Jeffrey Dalton, Xin Luna Dong, Lisette Espín-Noboa, Wenqi Fan, Manuela Fritz, Quan Gan, Jingtong Gao, Xiaojie Guo, Torsten Hahmann, Jiawei Han, Soyeon Caren Han, Estevam Hruschka, Liang Hu, Jiaxin Huang, Utkarshani Jaimini, Olivier Jeunen, Yushan Jiang, Fariba Karimi, George Karypis, Krishnaram Kenthapadi, Himabindu Lakkaraju, Hady W. Lauw, Thai Le, Trung-Hoang Le, Dongwon Lee, Geon Lee, Liat Levontin, Cheng-Te Li, Haoyang Li, Ying Li, Jay Chiehen Liao, Qidong Liu, Usha Lokala, Ben London, Siqu Long, Hande Küçük-McGinty, Yu Meng, Seungwhan Moon, Usman Naseem, Pradeep Natarajan, Behrooz Omidvar-Tehrani, Zijie Pan, Devesh Parekh, Jian Pei, Tiago Peixoto, Steven Pemberton, Josiah Poon, Filip Radlinski, Federico Rossetto, Kaushik Roy, Aghiles Salah, Mehrnoosh Sameki, Amit P. Sheth, Cogan Shimizu, Kijung Shin, Dongjin Song, Julia Stoyanovich, Dacheng Tao, Johanne Trippas, Quoc Truong, Yu-Che Tsai, Adaku Uchendu, Bram van den Akker, Lin Wang, Minjie Wang, Shoujin Wang, Xin Wang, Ingmar Weber, Henry Weld, Lingfei Wu, Da Xu, Yifan Ethan Xu, Shuyuan Xu, Bo Yang, Ke Yang, Elad Yom-Tov, Jaemin Yoo, Zhou Yu, Reza Zafarani, Hamed Zamani, Meike Zehlike, Qi Zhang, Xikun Zhang, Yongfeng Zhang, Yu Zhang, Zheng Zhang, Liang Zhao, Xiangyu Zhao, Wenwu Zhu

Proceedings of the Companion Proceedings of the ACM Web Conference 2023, 2023

GRADES-NDA'23: 6th Joint Workshop on Graph Data Management Experiences & Systems (GRADES) and Network Data Analytics (NDA).

Olaf Hartig, Yuichi Yoshida

Proceedings of the Companion of the 2023 International Conference on Management of Data, 2023

FedShop: A Benchmark for Testing the Scalability of SPARQL Federation Engines.

Minh Hoang Dang, Julien Aimonier-Davat, Pascal Molli, Olaf Hartig, Hala Skaf-Molli, Yotlan Le Crom

Proceedings of the Semantic Web - ISWC 2023, 2023

OBG-gen: Ontology-Based GraphQL Server Generation for Data Integration.

Huanyu Li, Olaf Hartig, Rickard Armiento, Patrick Lambrix

Proceedings of the ISWC 2023 Posters, 2023

A Cost Model to Optimize Queries over Heterogeneous Federations of RDF Data Sources.

Sijin Cheng, Olaf Hartig

Proceedings of the Joint Proceedings of the ESWC 2023 Workshops and Tutorials co-located with 20th European Semantic Web Conference (ESWC 2023), 2023

Preface.

Christian Aebeloe, Amr Azzam, Olaf Hartig, Katja Hose

Proceedings of the Joint Proceedings of the ESWC 2023 Workshops and Tutorials co-located with 20th European Semantic Web Conference (ESWC 2023), 2023

Transforming Event Knowledge Graph to Object-Centric Event Logs: A Comparative Study for Multi-dimensional Process Analysis.

Shahrzad Khayatbashi, Olaf Hartig, Amin Jalali

Proceedings of the Conceptual Modeling - 42nd International Conference, 2023

Considering Vocabulary Mappings in Query Plans for Federations of RDF Data Sources.

Sijin Cheng, Sebastián Ferrada, Olaf Hartig

Proceedings of the Cooperative Information Systems - 29th International Conference, 2023

2022

Assessing the Solid Protocol in Relation to Security & Privacy Obligations.

Christian Esposito, Olaf Hartig, Ross Horne, Chang Sun

CoRR, 2022

LinGBM: A Performance Benchmark for Approaches to Build GraphQL Servers (Extended Version).

Sijin Cheng, Olaf Hartig

CoRR, 2022

LinGBM: A Performance Benchmark for Approaches to Build GraphQL Servers.

Sijin Cheng, Olaf Hartig

Proceedings of the Web Information Systems Engineering - WISE 2022, 2022

Source Selection for SPARQL Endpoints: Fit for Heterogeneous Federations of RDF Data Sources?

Sijin Cheng, Olaf Hartig

Proceedings of the QuWeDa 2022: 6th Workshop on Storing, 2022

Converting property graphs to RDF: a preliminary study of the practical impact of different mappings.

Shahrzad Khayatbashi, Sebastián Ferrada, Olaf Hartig

Proceedings of the GRADES-NDA '22: Proceedings of the 5th ACM SIGMOD Joint International Workshop on Graph Data Management Experiences & Systems (GRADES) and Network Data Analytics (NDA), 2022

Towards Query Processing over Heterogeneous Federations of RDF Data Sources.

Sijin Cheng, Olaf Hartig

Proceedings of the Semantic Web: ESWC 2022 Satellite Events - Hersonissos, Crete, Greece, May 29, 2022

2021

The future is big graphs: a community view on graph processing systems.

Sherif Sakr, Angela Bonifati, Hannes Voigt, Alexandru Iosup, Khaled Ammar, Renzo Angles, Walid G. Aref, Marcelo Arenas, Maciej Besta, Peter A. Boncz, Khuzaima Daudjee, Emanuele Della Valle, Stefania Dumbrava, Olaf Hartig, Bernhard Haslhofer, Tim Hegeman, Jan Hidders, Katja Hose, Adriana Iamnitchi, Vasiliki Kalavri, Hugo Kapp, Wim Martens, M. Tamer Özsu, Eric Peukert, Stefan Plantikow, Mohamed Ragab, Matei Ripeanu, Semih Salihoglu, Christian Schulz, Petra Selmer, Juan F. Sequeda, Joshua Shinavier, Gábor Szárnyas, Riccardo Tommasini, Antonino Tumeo, Alexandru Uta, Ana Lucia Varbanescu, Hsiang-Yun Wu, Nikolay Yakovets, Da Yan, Eiko Yoneki

Commun. ACM, 2021

Optimizing RDF Stream Processing for Uncertainty Management.

Robin Keskisärkkä, Eva Blomqvist, Olaf Hartig

Proceedings of the Further with Knowledge Graphs, 2021

2020

FedQPL: A Language for Logical Query Plans over Heterogeneous Federations of RDF Data Sources (Extended Version).

Sijin Cheng, Olaf Hartig

CoRR, 2020

FedQPL: A Language for Logical Query Plans over Heterogeneous Federations of RDF Data Sources.

Sijin Cheng, Olaf Hartig

Proceedings of the iiWAS '20: The 22nd International Conference on Information Integration and Web-based Applications & Services, Virtual Event / Chiang Mai, Thailand, November 30, 2020

Capturing and Querying Uncertainty in RDF Stream Processing.

Robin Keskisärkkä, Eva Blomqvist, Leili Lind, Olaf Hartig

Proceedings of the Knowledge Engineering and Knowledge Management, 2020

2019

Linked Data Management.

Olaf Hartig, Katja Hose, Juan F. Sequeda

Proceedings of the Encyclopedia of Big Data Technologies., 2019

Federated RDF Query Processing.

Maribel Acosta, Olaf Hartig, Juan F. Sequeda

Proceedings of the Encyclopedia of Big Data Technologies., 2019

OPT+: A Monotonic Alternativeto OPTIONAL in SPARQL.

Sijin Cheng, Olaf Hartig

J. Web Eng., 2019

RSP-QL $$^{\star }\!$$ : Enabling Statement-Level Annotations in RDF Streams.

Robin Keskisärkkä, Eva Blomqvist, Leili Lind, Olaf Hartig

Proceedings of the Semantic Systems. The Power of AI and Knowledge Graphs, 2019

Foundations to Query Labeled Property Graphs using SPARQL.

Olaf Hartig

Proceedings of the Joint Proceedings of the 1st International Workshop On Semantics For Transport and the 1st International Workshop on Approaches for Making Data Interoperable co-located with 15th Semantics Conference (SEMANTiCS 2019), 2019

Defining Schemas for Property Graphs by using the GraphQL Schema Definition Language.

Olaf Hartig, Jan Hidders

Proceedings of the 2nd Joint International Workshop on Graph Data Management Experiences & Systems (GRADES) and Network Data Analytics (NDA), 2019

An Empirical Analysis of GraphQL API Schemas in Open Code Repositories and Package Registries.

Yun Wan Kim, Mariano P. Consens, Olaf Hartig

Proceedings of the 13th Alberto Mendelzon International Workshop on Foundations of Data Management, 2019

2018

Semantics and Complexity of GraphQL.

Olaf Hartig, Jorge Pérez

Proceedings of the 2018 World Wide Web Conference on World Wide Web, 2018

A Model of Distributed Query Computation in Client-Server Scenarios on the Semantic Web.

Olaf Hartig, Ian Letter, Jorge Pérez

Proceedings of the Twenty-Seventh International Joint Conference on Artificial Intelligence, 2018

CostFed: Cost-Based Query Optimization for SPARQL Endpoint Federation.

Muhammad Saleem, Alexander Potocki, Tommaso Soru, Olaf Hartig, Axel-Cyrille Ngonga Ngomo

Proceedings of the 14th International Conference on Semantic Systems, 2018

2017

SPARQL with property paths on the Web.

Olaf Hartig, Giuseppe Pirrò

Semantic Web, 2017

Federated Semantic Data Management (Dagstuhl Seminar 17262).

Olaf Hartig, Maria-Esther Vidal, Johann-Christoph Freytag

Dagstuhl Reports, 2017

Semantic Data Management in Practice.

Olaf Hartig, Olivier Curé

Proceedings of the 26th International Conference on World Wide Web Companion, 2017

Federated SPARQL Query Processing Via CostFed.

Alexander Potocki, Muhammad Saleem, Tommaso Soru, Olaf Hartig, Martin Voigt, Axel-Cyrille Ngonga Ngomo

Proceedings of the ISWC 2017 Posters & Demonstrations and Industry Tracks co-located with 16th International Semantic Web Conference (ISWC 2017), Vienna, Austria, October 23rd - to, 2017

A Formal Framework for Comparing Linked Data Fragments.

Olaf Hartig, Ian Letter, Jorge Pérez

Proceedings of the Semantic Web - ISWC 2017, 2017

RDF* and SPARQL*: An Alternative Approach to Annotate Statements in RDF.

Olaf Hartig

Proceedings of the ISWC 2017 Posters & Demonstrations and Industry Tracks co-located with 16th International Semantic Web Conference (ISWC 2017), Vienna, Austria, October 23rd - to, 2017

Foundations of RDF⋆ and SPARQL⋆ (An Alternative Approach to Statement-Level Metadata in RDF).

Olaf Hartig

Proceedings of the 11th Alberto Mendelzon International Workshop on Foundations of Data Management and the Web, 2017

An Initial Analysis of Facebook's GraphQL Language.

Olaf Hartig, Jorge Pérez

Proceedings of the 11th Alberto Mendelzon International Workshop on Foundations of Data Management and the Web, 2017

2016

Querying a Web of Linked Data - Foundations and Query Execution

Olaf Hartig

Studies on the Semantic Web 24, IOS Press, ISBN: 978-1-61499-631-6, 2016

Triple Pattern Fragments: A low-cost knowledge graph interface for the Web.

Ruben Verborgh, Miel Vander Sande, Olaf Hartig, Joachim Van Herwegen, Laurens De Vocht, Ben De Meester, Gerald Haesendonck, Pieter Colpaert

J. Web Semant., 2016

LDQL: A query language for the Web of Linked Data.

Olaf Hartig, Jorge Pérez

J. Web Semant., 2016

Scheduling Refresh Queries for Keeping Results from a SPARQL Endpoint Up-to-Date (Extended Version).

Magnus Knuth, Olaf Hartig, Harald Sack

CoRR, 2016

Walking without a Map: Optimizing Response Times of Traversal-Based Linked Data Queries (Extended Version).

Olaf Hartig, M. Tamer Özsu

CoRR, 2016

brTPF: Bindings-Restricted Triple Pattern Fragments (Extended Preprint).

Olaf Hartig, Carlos Buil-Aranda

CoRR, 2016

Walking Without a Map: Ranking-Based Traversal for Querying Linked Data.

Olaf Hartig, M. Tamer Özsu

Proceedings of the Semantic Web - ISWC 2016, 2016

Reducing the Network Load of Triple Pattern Fragments by Supporting Bind Joins.

Olaf Hartig, Carlos Buil-Aranda

Proceedings of the ISWC 2016 Posters & Demonstrations Track co-located with 15th International Semantic Web Conference (ISWC 2016), 2016

Scheduling Refresh Queries for Keeping Results from a SPARQL Endpoint Up-to-Date (Short Paper).

Magnus Knuth, Olaf Hartig, Harald Sack

Proceedings of the On the Move to Meaningful Internet Systems: OTM 2016 Conferences, 2016

Bindings-Restricted Triple Pattern Fragments.

Olaf Hartig, Carlos Buil-Aranda

Proceedings of the On the Move to Meaningful Internet Systems: OTM 2016 Conferences, 2016

2015

LDQL: A Query Language for the Web of Linked Data (Extended Version).

Olaf Hartig, Jorge Pérez

CoRR, 2015

A Context-Based Semantics for SPARQL Property Paths over the Web (Extended Version).

Olaf Hartig, Giuseppe Pirrò

CoRR, 2015

Executing queries over schemaless RDF databases.

Günes Aluç, M. Tamer Özsu, Khuzaima Daudjee, Olaf Hartig

Proceedings of the 31st IEEE International Conference on Data Engineering, 2015

A Context-Based Semantics for SPARQL Property Paths Over the Web.

Olaf Hartig, Giuseppe Pirrò

Proceedings of the Semantic Web. Latest Advances and New Domains, 2015

LDQL: A Language for Linked Data Queries.

Olaf Hartig

Proceedings of the 9th Alberto Mendelzon International Workshop on Foundations of Data Management, Lima, Peru, May 6, 2015

2014

Querying a Web of Linked Data.

Olaf Hartig

PhD thesis, 2014

Querying a web of linked data: foundations and query execution.

Olaf Hartig

SIGWEB Newsl., 2014

Foundations of an Alternative Approach to Reification in RDF.

Olaf Hartig, Bryan Thompson

CoRR, 2014

Reconciliation of RDF* and Property Graphs.

Olaf Hartig

CoRR, 2014

Reachable subwebs for traversal-based query execution.

Olaf Hartig, M. Tamer Özsu

Proceedings of the 23rd International World Wide Web Conference, 2014

Low-Cost Queryable Linked Data through Triple Pattern Fragments.

Ruben Verborgh, Olaf Hartig, Ben De Meester, Gerald Haesendonck, Laurens De Vocht, Miel Vander Sande, Richard Cyganiak, Pieter Colpaert, Erik Mannens, Rik Van de Walle

Proceedings of the ISWC 2014 Posters & Demonstrations Track a track within the 13th International Semantic Web Conference, 2014

Querying Datasets on the Web with High Availability.

Ruben Verborgh, Olaf Hartig, Ben De Meester, Gerald Haesendonck, Laurens De Vocht, Miel Vander Sande, Richard Cyganiak, Pieter Colpaert, Erik Mannens, Rik Van de Walle

Proceedings of the Semantic Web - ISWC 2014, 2014

Overview of METHOD 2014: the 3rd International Workshop on Methods for Establishing Trust of (Open) Data.

Tom De Nies, Davide Ceolin, Paul Groth, Olaf Hartig, Stephen Marsh

Proceedings of the 10th International Workshop on Uncertainty Reasoning for the Semantic Web (URSW 2014) co-located with the 13th International Semantic Web Conference (ISWC 2014), 2014

Diversified Stress Testing of RDF Data Management Systems.

Günes Aluç, Olaf Hartig, M. Tamer Özsu, Khuzaima Daudjee

Proceedings of the Semantic Web - ISWC 2014, 2014

Linked Data query processing.

Olaf Hartig, M. Tamer Özsu

Proceedings of the IEEE 30th International Conference on Data Engineering, Chicago, 2014

Linked Data Query Processing Based on Link Traversal.

Olaf Hartig

Proceedings of the Linked Data Management., 2014

2013

An Overview on Execution Strategies for Linked Data Queries.

Olaf Hartig

Datenbank-Spektrum, 2013

SQUIN: a traversal based query execution system for the web of linked data.

Olaf Hartig

Proceedings of the ACM SIGMOD International Conference on Management of Data, 2013

2012

SPARQL for a Web of Linked Data: Semantics and Computability (Extended Version)

Olaf Hartig

CoRR, 2012

Towards Interoperable Provenance Publication on the Linked Data Web.

Jun Zhao, Olaf Hartig

Proceedings of the WWW2012 Workshop on Linked Data on the Web, 2012

Populating personal linked data caches using context models.

Olaf Hartig, Tom Heath

Proceedings of the 21st World Wide Web Conference, 2012

An Introduction to SPARQL and Queries over Linked Data.

Olaf Hartig

Proceedings of the Web Engineering - 12th International Conference, 2012

Query prediction with context models for populating personal linked data caches.

Olaf Hartig, Tom Heath

Proceedings of the 23rd ACM Conference on Hypertext and Social Media, 2012

Foundations of traversal based query execution over linked data.

Olaf Hartig, Johann-Christoph Freytag

Proceedings of the 23rd ACM Conference on Hypertext and Social Media, 2012

SPARQL for a Web of Linked Data: Semantics and Computability.

Olaf Hartig

Proceedings of the Semantic Web: Research and Applications, 2012

2011

Towards a Query Language for the Web of Data (A Vision Paper)

Juan F. Sequeda, Olaf Hartig

CoRR, 2011

Foundations of Traversal Based Query Execution over Linked Data (Extended Version)

Olaf Hartig, Johann Christoph Freytag

CoRR, 2011

A Main Memory Index Structure to Query Linked Data.

Olaf Hartig, Frank Huber

Proceedings of the WWW2011 Workshop on Linked Data on the Web, 2011

How Caching Improves Efficiency and Result Completeness for Querying Linked Data.

Olaf Hartig

Proceedings of the WWW2011 Workshop on Linked Data on the Web, 2011

Zero-Knowledge Query Planning for an Iterator Implementation of Link Traversal Based Query Execution.

Olaf Hartig

Proceedings of the Semantic Web: Research and Applications, 2011

2010

A Database Perspective on Consuming Linked Data on the Web.

Olaf Hartig, Andreas Langegger

Datenbank-Spektrum, 2010

How to consume linked data on the web: tutorial description.

Olaf Hartig, Juan F. Sequeda, Jamie Taylor, Patrick Sinclair

Proceedings of the 19th International Conference on World Wide Web, 2010

Publishing and Consuming Provenance Metadata on the Web of Linked Data.

Olaf Hartig, Jun Zhao

Proceedings of the Provenance and Annotation of Data and Processes, 2010

2009

Provenance Information in the Web of Data.

Olaf Hartig

Proceedings of the WWW2009 Workshop on Linked Data on the Web, 2009

Using Web Data Provenance for Quality Assessment.

Olaf Hartig, Jun Zhao

Proceedings of the First International Workshop on the role of Semantic Web in Provenance Management (SWPM 2009), 2009

Executing SPARQL Queries over the Web of Linked Data.

Olaf Hartig, Christian Bizer, Johann Christoph Freytag

Proceedings of the Semantic Web - ISWC 2009, 8th International Semantic Web Conference, 2009

Linked Data for Building a Map of Researchers.

Olaf Hartig, Hannes Mühleisen, Johann-Christoph Freytag

Proceedings of the Fifth Workshop on Scripting and Development for the Semantic Web , 2009

Querying Trust in RDF Data with tSPARQL.

Olaf Hartig

Proceedings of the Semantic Web: Research and Applications, 2009

2008

Designing Component-Based Semantic Web Applications with DESWAP.

Olaf Hartig, Martin Kost, Johann Christoph Freytag

Proceedings of the Poster and Demonstration Session at the 7th International Semantic Web Conference (ISWC2008), 2008

2007

The SPARQL Query Graph Model for Query Optimization.

Olaf Hartig, Ralf Heese

Proceedings of the Semantic Web: Research and Applications, 2007