Research Interests

I am interested in the management of graph data. My forcus is on problems related to query processing over a heterogeneous federation of graph data.

Publications

There is a list of my publications:

• Sijin Cheng, Sebastián Ferrada and Olaf Hartig: Considering Vocabulary Mappings in Query Plans for Federations of RDF Data Sources. In The 29th International Conference on Cooperative Information Systems (CoopIS), Groningen, Netherlands, Oct. 2023 (Best Paper Award winner) download camera-ready version

• Sijin Cheng and Olaf Hartig: A Cost Model to Optimize Queries over Heterogeneous Federations of RDF Data Sources. In DMKG Workshop at the 20th Extended Semantic Web Conference (ESWC), Hersonissos, Greece, Jun. 2023 download camera-ready version

• Sijin Cheng and Olaf Hartig: Source Selection for SPARQL Endpoints: Fit for Heterogeneous Federations of RDF Data Sources?. In QuWeDa Workshop at the 21st International Semantic Web Conference (ISWC), Hangzhou, China, Oct. 2022 download camera-ready version

• Sijin Cheng and Olaf Hartig: LinGBM: A Performance Benchmark for Approaches to Build GraphQL Servers. In In Proceedings of the 23rd International Conference on Web Information Systems Engineering (WISE), Biarritz, France, Nov. 2022 download camera-ready version   extended version on arXiv (abs/2208.04784)   Github repo for LinGBM   Github repo for experiment code

• Sijin Cheng and Olaf Hartig: Towards Query Processing over Heterogeneous Federations of RDF Data Sources. In Proceedings of the Poster Session at the 19th Extended Semantic Web Conference (ESWC), Hersonissos, Greece, Jun. 2022

• Sijin Cheng and Olaf Hartig: FedQPL: A Language for Logical Query Plans over Heterogeneous Federations of RDF Data Sources. In Proceedings of the 22nd International Conference on Information Integration and Web-based Applications & Services (iiWAS), Nov. 2020 (Best Paper Award winner)

• Sijin Cheng and Olaf Hartig: OPT+: A Monotonic Alternative to OPTIONAL in SPARQL. In Journal of Web Engineering 18(1-3), pages 169-206. 2019 (Notice, the linked PDF is a pre-print. The final publication is available via DOI 10.13052/jwe1540-9589.18135.)

• Robin Keskisärkkä, Huanyu Li, Sijin Cheng, Niklas Carlsson, Patrick Lambrix: An Ontology for Ice Hockey. In Proceedings of the Poster Session at the 18th International Semantic Web Conference (ISWC), Auckland, New Zealand, Oct. 2019

Program Committees

• 22rd International Semantic Web Conference (ISWC), October 2023, Athens, Greece   (PC Member of Research track)
• 20th Extended Semantic Web Conference (ESWC), June 2023, Hersonissos, Greece   (PC Member of Research track)
• 1st International Workshop on Data Management for Knowledge Graphs (DMKG2023), June 2023, Hersonissos, Greece   (PC Member)
• 21st International Semantic Web Conference (ISWC), October 2022, Hangzhou, China   (PC Member of Research track)
• 19th International Semantic Web Conference (ISWC), November 2020, Athens, Greece   (PC Member of Reproducibility)

Journal Reviews

• Transactions on the Web (TWEB), 2021
• The Semantic Web Journal (SWJ), 2023

Additional Activities

• International Conference on Web Information Systems Engineering (WISE), 2022, Session Chair of "Query Processing & Information Extraction"
• The Web Conference, 2021, subreviewer
• The 4rth Workshop on Storing, Querying, and Benchmarking the Web of Data (QuWeDa) at ISWC, 2020, subreviewer

Teaching

Courses at LiU for which I was responsible as a teaching assistant:

• Spring (HT2) 2023: Database Technology (TDDD12)
• Spring (HT1/2) 2023: Database Technology (TDDD81)
• Fall (HT2) 2022: Database Technology (TDDD37)
• Spring (VT2) 2022: Databases and information security for bioinformatics (TDDE49)
• Spring (VT2) 2022: Database Technology (TDDD12)
• Spring (VT2) 2021: Databases and information security for bioinformatics (TDDE49)
• Spring (VT1/2) 2021: Database Technology (TDDD81)
• Fall (HT2) 2020: Database Technology (TDDD37 / 732A57)
• Spring (VT1/2) 2020: Database Technology (TDDD81)
• Spring (VT2) 2020: Databases for Bioinformatics (TDDD74)
• Fall (HT2) 2019: Database Technology (TDDD37 / TDDD46 / 732A57)
• Spring (VT2) 2019: Database Technology (TDDD12)
• Fall (HT2) 2018: Database Technology (TDDD37 / 732A57)
• Spring (VT2) 2018: Database Technology (TDDD12)

Supervision of Master and Bachelor students at LiU:

• Simon Helgesson, "Vocabulary-Mapping Operators for Federated Query Plans"
• Albin Pettersson, "An Investigation of Source Selection Approaches for Federated RDF Query Processing"