Senior Research Scientist | Semantic Technologies for Industrial Data
I am a senior research scientist at Siemens AG Österreich and an external lecturer at IMC Krems, specializing in semantic technologies, knowledge graphs, and numerical reasoning in RDF. My work focuses on making industrial data interoperable, actionable, and intelligent—enabling machines and humans to work with structured, connected, and validated knowledge.
With a PhD in Computer Science from TU Wien, I explored methods to prepare Linked Data for analysis, laying the foundation for my current research at the intersection of symbolic reasoning (ontologies, SHACL, SPARQL) and industrial applications, including:
- Industrial knowledge graphs for rail infrastructure, smart buildings, and manufacturing.
- Numerical data processing in RDF, including calculations, data repair, and validation.
- Hybrid AI approaches that combine semantic technologies with generative models for ontology engineering and data interoperability.
I am particularly interested in how semantic frameworks can transform industrial systems, making them more transparent, efficient, and adaptable.
Publications
Find a list of most of my publications on DBLP, Google Scholar, ORCID, Scopus or Semantic Scholar.
Journal Articles
T. Iggena, E. Bin Ilyas, M. Fischer, R. Tönjes, T. Elsaleh, R. Rezvani, N. Pourshahrokhi, S. Bischof, A. Fernbach, J. Xavier Parreira, P. Schneider, P. Smirnov, M. Strohbach, H. Truong, A. González-Vidal, A. F. Skarmeta, P. Singh, M. J. Beliatis, M. Presser, J. A. Martinez, P. Gonzalez-Gil, M. Krogbæk, S. Holmgård Christophersen IoTCrawler: Challenges and Solutions for Searching the Internet of Things. Sensors. 2021. [ DOI ]
Stefan Bischof, Andreas Harth, Benedikt Kämpgen, Axel Polleres, Patrik Schneider Enriching Integrated Statistical Open City Data by Combining Equational Knowledge and Missing Value Imputation. Journal of Web Semantics: Special Issue on Semantic Statistics. 2017. [ DOI | Preprint ]
Stefan Bischof, Stefan Decker, Thomas Krennwallner, Nuno Lopes, Axel Polleres Mapping between RDF and XML with XSPARQL. Journal on Data Semantics. 2012. [ DOI | PDF ]
Conference Articles
Stefan Bischof, Erwin Filtz, Josiane Xavier Parreira Semantic Smart Readiness Indicator Framework. SEMANTiCS. 2024. [ DOI | Ontology | Zenodo ]
Abstract
The Smart Readiness Indicator (SRI) is an energy rating scheme targeted at buildings to evaluate their capacity to integrate and benefit from smart technologies for enhanced energy efficiency and overall performance. Existing tools for SRI assessment and rating do not provide a standard format for data exchange. However, there are several scenarios in which a FAIR, standardised data format is beneficial, such as data exchange between building tools, comparison of different assessments, or computing statistics about buildings.
Stefan Bischof, Erwin Filtz, Josiane Xavier Parreira, Simon Steyskal LLM-based Guided Generation of Ontology Term Definitions. ESWC 2024 Industry Track. 2024. [ DOI | PDF ]
Abstract
This paper describes our approach for leveraging LLMs to generate definitions and descriptions for ontology terms. Our approach is grounded in the need for detailed and accurate representation of (domain-specific) Knowledge Graphs, and it aims at speeding up the process of generating such text. We outline our approach, including the problems that we encountered, and the solution we propose to overcome them. Our approach is currently in use in an industrial setting.
Stefan Bischof, Gottfried Schenner Rail Topology Ontology: A Rail Infrastructure Base Ontology. ISWC 2021 Resource Track. 2021. [ arXiv preprint | Video | DOI | ontology ]
Stefan Bischof, Gottfried Schenner Challenges of Constructing a Railway Knowledge Graph. ESWC 2019 Industry Track. 2019. [ DOI | Video | PDF ]
Dan Puiu, Stefan Bischof, Bogdan Serbanescu, Septimiu Nechifor, Josiane Parreira, Herwig Schreiner A public transportation journey planner enabled by IoT data analytics. Conference on Innovations in Clouds, Internet and Networks. 2017. [ DOI | PDF ]
Stefan Bischof, Christoph Martin, Axel Polleres, Patrik Schneider Collecting, Integrating, Enriching and Republishing Open City Data as Linked Data. ISWC 2015. 2015. [ DOI | Video | PDF ]
Stefan Bischof, Markus Krötzsch, Axel Polleres, Sebastian Rudolph Schema-Agnostic Query Rewriting for OWL QL. Workshop on Description Logics. 2015. [ CEUR ]
Stefan Bischof, Markus Krötzsch, Axel Polleres, Sebastian Rudolph Schema-Agnostic Query Rewriting in SPARQL 1.1. ISWC 2014. 2014. [ DOI | PDF ]
Axel Polleres, Stefan Bischof, Herwig Schreiner City Data Pipeline - A report about experiences from using Open Data to gather indicators of city performance. European Data Forum. 2014. [ Video | Slides ]
Stefan Bischof, Axel Polleres RDFS with Attribute Equations via SPARQL Rewriting. ESWC 2013. 2013. [ DOI | Video | Slides | PDF ]
Aidan Boran, Ivan Bedini, Christopher J. Matheus, Peter F. Patel-Schneider, Stefan Bischof An Empirical Analysis of Semantic Techniques Applied to a Network Management Classification Problem. IEEE/WIC/ACM International Conference on Web Intelligence and Intelligent Agent Technology. 2012. [ DOI ]
Stefan Bischof Optimising XML-RDF Data Integration. Extended Semantic Web Conference. 2012. [ DOI | PDF ]
Stefan Bischof, Nuno Lopes, Axel Polleres Improve Efficiency of Mapping Data between XML and RDF with XSPARQL. Web Reasoning and Rule Systems. 2011. [ DOI | PDF ]
Nuno Lopes, Stefan Bischof, Stefan Decker, Axel Polleres On the Semantics of Heterogeneous Querying of Relational, XML and RDF Data with XSPARQL. Portuguese Conference on Artificial Intelligence. 2011. [ http ]
Workshop and Poster Articles
Stefan Bischof, Erwin Filtz, Josiane Xavier Parreira, Florian Rötzer, Simon Steyskal, Stephan Strommer On A Semantic Model and Knowledge Graph Based Approach to Enable Transparency, Explainability, and Auditability for High-Pressure Die-Casting. SENTIS Workshop. 2025. [ CEUR ]
Abstract
This paper addresses the critical challenge of fragmented data and knowledge in high-pressure die-casting environments, where the lack of integrated information hampers effective troubleshooting and compliance with emerging transparency requirements. We developed a comprehensive semantic model that integrates distributed data sources and expert knowledge into a unified knowledge graph framework, explicitly connecting manufacturing processes, failures, metrics, and countermeasures through formalized semantic relationships. Our implementation shows how the resulting architecture successfully transforms traditionally siloed industrial data into an interconnected knowledge representation that distinguishes between specified expert knowledge and actual operational data, enabling systematic reasoning about cause-effect relationships throughout the manufacturing process. The approach provides significant value by enhancing manufacturing transparency and decision support while aligning with Industry 5.0 principles and emerging regulatory frameworks for explainable industrial systems, ultimately supporting more sustainable and efficient manufacturing processes.
Robert David, Stefan Bischof, Konrad Diwold, Josiane Xavier Parreira Symbolic-AI driven Data Repairs for Large Scale Energy Co-Simulations: Combining SHACL repairs and Datalog rules to detect, explain, and correct errors in large scale energy co-simulation setups. Posters and Demos Track of SEMANTiCS. 2025. [ CEUR ]
Abstract
The transformation of energy distribution systems is fostering new models, like renewable energy communities, which require complex, simulation-based feasibility assessments. Preparing these simulations is often labor-intensive and error-prone due to heterogeneous actors and location-specific grid topologies. This paper proposes a symbolic AI approach that combines SHACL (repairs) and Datalog (imputation) to semi-automatically detect, explain, and correct inconsistencies for grid and sensor data so it can serve as input for co-simulations. Applied within the DataBri-X project and tested using Siemens BIFROST, the approach demonstrates promising improvements in data quality and preprocessing efficiency.
Stefan Bischof, Andreas Falkner, Erwin Filtz, Patrik Schneider, Simon Steyskal, Mihaela Topa CONTO: An Ontology-based Approach for Interoperable Configuration Knowledge. Posters and Demos Track of SEMANTiCS. 2025. [ CEUR ]
Abstract
CONTO (CONfiguration ONTOlogy and TOols) addresses the challenges of vendor lock-in and costly evaluations in product configuration systems through an ontology-based semantic framework that establishes interoperability without reinventing existing solver technologies. Our approach provides dual representations--instance-based Configuration Vocabulary and OWL DL-based formalism--with tooling to transform product models into programs for various platforms. By decoupling modelling from configuration processing, CONTO creates an abstraction layer that preserves existing investments while enabling integration with emerging AI tools. Our implementation shows practical applications supporting both commercial and open-source configurators.
Stefan Bischof, Gottfried Schenner On Linking Heterogeneous Railway Knowledge Graphs: Challenges in Integrating ERA and OpenStreetMap Rail Infrastructure Representations. Sem4Tra Workshop. 2025. [ CEUR | PDF ]
Abstract
In the last years railway infrastructure data has become available via public SPARQL endpoints. The ontologies/vocabularies used to represent the topology part of the railway data are mainly based either on the Open Street Map (OSM) data model or on the UML-based RailTopoModel. In this paper we discuss some of the challenges of integrating railway infrastructure data especially topological data. As an example, we show how to link the data available for the Austrian railway network using Open Street Map data via the QLever SPARQL endpoint and data from the ERA Knowledge Graph.
Stefan Bischof, Erwin Filtz, Josiane Xavier Parreira, Simon Steyskal, Michael Baumgart, David Gruber, Maximilian Liebetreu, Florian Rötzer, Stephan Strommer Towards SHACL-based Knowledge Graph Transformation of Visual Domain Knowledge. Posters and Demos Track of SEMANTiCS. 2024. [ CEUR ]
Stefan Bischof, Gottfried Schenner Towards a Railway Topology Ontology to Integrate and Query Rail Data Silos. Posters and Demos Track of ISWC. 2020. [ CEUR | Video ]
Stefan Bischof, Gottfried Schenner, Simon Steyskal, Richard Taupe Integrating Semantic Web Technologies and ASP for Product Configuration. Config Workshop. 2018. [ CEUR ]
Mónica Posada-Sánchez, Stefan Bischof, Axel Polleres Extracting Geo-Semantics About Cities From OpenStreetMap. Posters and Demos Track of SEMANTiCS. 2016. [ CEUR ]
Stefan Bischof Improving Practical Reasoning on top of SPARQL. Doctoral Consortium of the International Conference on Web Reasoning and Rule Systems. 2015. [ PDF ]
Stefan Bischof, Christoph Martin, Axel Polleres, Patrik Schneider Open City Data Pipeline: Collecting, Integrating, and Predicting Open City Data. Workshop on Knowledge Discovery and Data Mining Meets Linked Open Data co-located with Extended Semantic Web Conference. 2015. [ CEUR ]
Stefan Bischof, Athanasios Karapantelakis, Cosmin-Septimiu Nechifor, Amit Sheth, Alessandra Mileo, Payam Barnaghi Semantic Modelling of Smart City Data. W3C Workshop on the Web of Things. 2014. [ PDF ]
Daniele Dell'Aglio, Axel Polleres, Nuno Lopes, Stefan Bischof Querying the Web of Data with XSPARQL 1.1. ISWC2014 Developers Workshop. 2014. [ CEUR ]
Gottfried Schenner, Stefan Bischof, Axel Polleres, Simon Steyskal Integrating Distributed Configurations with RDFS and SPARQL. Config Workshop. 2014. [ CEUR ]
Stefan Bischof, Axel Polleres, Simon Sperl City Data Pipeline - A System for Making Open Data Useful for Cities. I-SEMANTICS Posters & Demonstrations Track. 2013. [ CEUR ]
Nuno Lopes, Stefan Bischof, Orri Erling, Axel Polleres, Alexandre Passant, Diego Berrueta, Antonio Campos, Jérôme Euzenat, Kingsley Idehen, Stefan Decker, Stéphane Corlosquet, Jacek Kopecky, Janne Saarela, Thomas Krennwallner, Davide Palmisano, Michal Zaremba RDF and XML: Towards a Unified Query Layer. W3C Workshop on RDF Next Steps. 2010. [ PDF ]
Patents
Stefan Bischof, Lukas Krammer, Daniel Lechner, Josef Wechselauer Building Automation Device and Method. 2019. Patent:EP3637204A1.[ Espacenet ]
Josiane Xavier Parreira, Stefan Bischof, Lukas Krammer, Andreas Fernbach Method for Automatically Computing Automation Capabilities of a Building. 2019. Patent:US2024330831A1.[ Espacenet ]
Theses
Stefan Bischof Complementary Methods for the Enrichment of Linked Data. Vienna University of Technology, Austria. 2017. (PhD thesis). [ DOI | Rigorosum slides ]
Stefan Bischof Implementation and Optimisation of Queries in XSPARQL. Vienna University of Technology, Austria. 2010. (Master's thesis). [ metadata | PDF ]
Other
Stefan Bischof, Benedikt Kämpgen, Andreas Harth, Axel Polleres, Patrik Schneider Open City Data Pipeline. Working Papers on Information Systems, Information Business and Operations 01/2017, Department für Informationsverarbeitung und Prozessmanagement, WU Vienna University of Economics and Business, Vienna, February 2017. 2017. [ http ]
Stefan Bischof, Markus Krötzsch, Axel Polleres, Sebastian Rudolph Schema-Agnostic Query Rewriting in SPARQL 1.1: Technical report. 2014. [ PDF ]
Programme committees and reviewing
AAAI, AMW, ESWC, ISWC, Semantics, Semantic Web Journal, Information Sciences, …
Contact me
Mail me at firstname@stefanbischof.at (replace firstname with my firstname).
Funded projects
- INBLANC: INdustrialisation of Building Lifecycle data Accumulation, Numeracy and Capitalisation, Horizon Europe
- DG Assist: Agile & nachhaltige Produktion im diskontinuierlichen Druckgussprozess durch ein menschzentriertes Assistenzsystem, Austria FFG
- DataBri-X: Data Process & Technological Bricks for expanding digital value creation in European Data Spaces, Horizon Europe
- PHOENIX: Adapt-&-Play Holistic cOst-Effective and user-frieNdly Innovations with high replicability to upgrade smartness of eXisting buildings with legacy equipment, EU Horizon 2020
- IoTCrawler: a search engine for Internet of Things devices, EU Horizon 2020
- RESIN: Climate Resilient Cities and Infrastructures, EU Horizon 2020
- BProfEM: Building Profiling for Energy Management, Austria FFG
- CityPulse: Real-Time IoT Stream Processing and Large-scale Data Analytics for Smart City Applications EU FP7
- SEE: SPARQL Evaluation and Extensions Vienna WWTF
- Transform+: Austria FFG