Leif Harald Karlsen

• Karlsen, Leif Harald (2023). Lore: Educational Deductive Database System. Lecture Notes in Computer Science (LNCS). ISSN 0302-9743. doi: 10.1007/978-3-031-45072-3_10. Fulltekst i vitenarkiv
• Yu, Ingrid Chieh; Pene, Irina; Din, Crystal Chang; Karlsen, Leif Harald; Nguyen, Chi Mai & Stahl, Oliver [Vis alle 7 forfattere av denne artikkelen] (2022). Subsurface Evaluation Through Multi-scenario Reasoning. I Patel, Daniel (Red.), Interactive Data Processing and 3D Visualization of the Solid Earth. Springer Nature. ISSN 9783030907150. s. 325–355. doi: 10.1007/978-3-030-90716-7_10. Fulltekst i vitenarkiv
• Kindermann, Christian; Lupp, Daniel P.; Skjæveland, Martin G & Karlsen, Leif Harald (2021). Formal Relations over Ontology Patterns in Templating Frameworks. I Blomqvist, Eva; Hahmann, Torsten; Hammar, Karl; Hitzler, Pascal; Hoekstra, Rinke; Mutharaju, Raghava; Poveda-Villalon, Maria; Shimizu, Cogan; Skjæveland, Martin G; Solanki, Monika; Svátek, Vojtěch & Zhou, Lu (Red.), Advances in Pattern-Based Ontology Engineering. IOS Press. ISSN 9781643681740. s. 120–133. doi: 10.3233/SSW210010. Fulltekst i vitenarkiv Vis sammendrag

  Ontologies are the corner stone of data modeling and knowledge representation, and engineering an ontology is a complex task in which domain knowledge, ontological accuracy and computational properties need to be carefully balanced. As with any engineering task, the identification and documentation of common patterns is important, and Ontology Design Patterns (ODPs) provide ontology designers with a strong connection to requirements and a better communication of their semantic content and intent. This book, Advances in Pattern-Based Ontology Engineering, contains 23 extended versions of selected papers presented at the annual Workshop on Ontology Design and Patterns (WOP) between 2017 and 2020. This yearly event, which attracts a large number of researchers and professionals in the field of ontology engineering and ontology design patterns, covers issues related to quality aspects of ontology engineering and ODPs for data and knowledge representation, and is usually co-located with the International Semantic Web Conference (ISWC), apart from WOP 2020, which was held virtually due to the COVID-19 pandemic. Topics covered by the papers collected here focus on recent advances in ontology design and patterns, and range from a method to instantiate content patterns, through a proposal on how to document a content pattern, to a number of patterns emerging in ontology modeling in various situations and applications. The book provides an overview of important advances in ontology engineering and ontology design patterns, and will be of interest to all those working in the field.

• Skjæveland, Martin G; Lupp, Daniel P.; Karlsen, Leif Harald & Kluwer, Johan Wilhelm (2021). OTTR: Formal Templates for Pattern-Based Ontology Engineering. I Blomqvist, Eva; Hahmann, Torsten; Hammar, Karl; Hitzler, Pascal; Hoekstra, Rinke; Mutharaju, Raghava; Poveda-Villalon, Maria; Shimizu, Cogan; Skjæveland, Martin G; Solanki, Monika; Svátek, Vojtěch & Zhou, Lu (Red.), Advances in Pattern-Based Ontology Engineering. IOS Press. ISSN 9781643681740. s. 349–377. doi: 10.3233/SSW210025. Fulltekst i vitenarkiv Vis sammendrag

  Ontologies are the corner stone of data modeling and knowledge representation, and engineering an ontology is a complex task in which domain knowledge, ontological accuracy and computational properties need to be carefully balanced. As with any engineering task, the identification and documentation of common patterns is important, and Ontology Design Patterns (ODPs) provide ontology designers with a strong connection to requirements and a better communication of their semantic content and intent. This book, Advances in Pattern-Based Ontology Engineering, contains 23 extended versions of selected papers presented at the annual Workshop on Ontology Design and Patterns (WOP) between 2017 and 2020. This yearly event, which attracts a large number of researchers and professionals in the field of ontology engineering and ontology design patterns, covers issues related to quality aspects of ontology engineering and ODPs for data and knowledge representation, and is usually co-located with the International Semantic Web Conference (ISWC), apart from WOP 2020, which was held virtually due to the COVID-19 pandemic. Topics covered by the papers collected here focus on recent advances in ontology design and patterns, and range from a method to instantiate content patterns, through a proposal on how to document a content pattern, to a number of patterns emerging in ontology modeling in various situations and applications. The book provides an overview of important advances in ontology engineering and ontology design patterns, and will be of interest to all those working in the field.

• Karlsen, Leif Harald & Giese, Martin (2019). Qualitatively correct bintrees: an efficient representation of qualitative spatial information. Geoinformatica. ISSN 1384-6175. 23(4), s. 689–731. doi: 10.1007/s10707-019-00348-z. Fulltekst i vitenarkiv
• Din, Crystal Chang; Karlsen, Leif Harald; Pene, Irina; Stahl, Oliver; Yu, Ingrid Chieh & Østerlie, Thomas (2019). Geological Multi-scenario Reasoning. NIKT: Norsk IKT-konferanse for forskning og utdanning. ISSN 1892-0713. Fulltekst i vitenarkiv Vis sammendrag

  In the oil and gas industry, during exploration prospect assessment, explorationists rely on ad hoc manual work practices and tools for developing and communicating multiple hypothetical geological scenarios of the prospect. This leaves them with little efficient means to make the fullest use of state of the art digital technologies to communicate and systematically compare and assess different hypothetical geological scenarios before deciding which scenario to pursue. In this paper, we present a formal framework for geological multi-scenario reasoning, a novel tool-based method for geologically oriented subsurface evaluation. The methodology applies formal methods and logic-based techniques to subsurface evaluation and expresses interpretive uncertainty as discrete scenarios with branches of potential alternatives. This framework consists of (i) a proto-scenario generator that takes user observations and geological evidence as input and generates semantically valid initial states based on formalized geological knowledge in first-order logic (ii) geological processes formalized as a rewrite theory that are executable in Maude. By applying geological rewrite rules onto the proto-scenarios, we are able to assist explorationists with multi-scenario generation and reasoning beyond human capacity.

• Skjæveland, Martin G; Lupp, Daniel P.; Karlsen, Leif Harald & Forssell, Jon Henrik (2018). Practical Ontology Pattern Instantiation, Discovery, and Maintenance with Reasonable Ontology Templates. Lecture Notes in Computer Science (LNCS). ISSN 0302-9743. 11136, s. 477–494. doi: 10.1007/978-3-030-00671-6_28. Fulltekst i vitenarkiv Vis sammendrag

  Reasonable Ontology Templates ( Open image in new window ) is a language for representing ontology modelling patterns in the form of parameterised ontologies. Ontology templates are simple and powerful abstractions useful for constructing, interacting with, and maintaining ontologies. With ontology templates, modelling patterns can be uniquely identified and encapsulated, broken down into convenient and manageable pieces, instantiated, and used as queries. Formal relations defined over templates support sophisticated maintenance tasks for sets of templates, such as revealing redundancies and suggesting new templates for representing implicit patterns. Ontology templates are designed for practical use; an Open image in new window vocabulary, convenient serialisation formats for the semantic web and for terse specification of template definitions and bulk instances are available, including an open source implementation for using templates. Our approach is successfully tested on a real-world large-scale ontology in the engineering domain.

• Skjæveland, Martin G; Karlsen, Leif Harald & Lupp, Daniel P. (2018). Practical Ontology Pattern Instantiation, Discovery, and Maintanence with Reasonable Ontology Templates - Demo paper. CEUR Workshop Proceedings. 2180. Fulltekst i vitenarkiv
• Lupp, Daniel Paul; Karlsen, Leif Harald & Skjæveland, Martin G (2018). Making a Case for Formal Relations over Ontology Patterns. CEUR Workshop Proceedings. 2195, s. 87–91. Fulltekst i vitenarkiv
• Karlsen, Leif Harald & Giese, Martin (2017). An Efficient Representation of General Qualitative Spatial Information using Bintrees. Leibniz International Proceedings in Informatics. 86, s. 1–15. doi: 10.4230/LIPIcs.COSIT.2017.4. Fulltekst i vitenarkiv Vis sammendrag

  In this paper we extend previous work on using bintrees as an efficient representation for qualitative information about spatial objects. Our approach represents each spatial object as a bintree satisfying the exact same qualitative relationships to other bintree representations as the corresponding spatial objects. We prove that such correct bintrees always exists and that they can be constructed as a sum of local representations, allowing a practically efficient construction. Our representation is both efficient, w.r.t. storage space and query time, and can represent many well-known qualitative relations, such as the relations in the Region Connection Calculus and Allen's Interval Algebra.

• Karlsen, Leif Harald & Giese, Martin (2015). A Framework for Constructing Correct Qualitative Representations of Geometries using Mereology over Bintrees. I Lechowski, Tomasz; Wałęga, Przemysław & Zawidzki, Michał (Red.), Proceedings of the LQMR 2015 Workshop. Polskie Towarzystwo Informatyczne. ISSN 9788360810781. s. 21–33. doi: 10.15439/978-83-60810-78-1. Fulltekst i vitenarkiv

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• Skjæveland, Martin G; Lupp, Daniel P. & Karlsen, Leif Harald (2020). Pattern-based knowledge base construction. Fulltekst i vitenarkiv
• Skjæveland, Martin G; Lupp, Daniel P.; Karlsen, Leif Harald & Hodkiewicz, M. R. (2019). Scalable Construction of Sustainable Knowledge Bases - Full day tutorial. Fulltekst i vitenarkiv
• Skjæveland, Martin G; Karlsen, Leif Harald & Lupp, Daniel P. (2019). IOF Workshops 2019 Tutorial: Ontology patterns in practice. Fulltekst i vitenarkiv
• Snilsberg, Erik; Karlsen, Leif Harald; Kostylev, Egor V. & Skjæveland, Martin G (2024). Foundations of ontology template language OTTR (extended abstract), in proceedings of the 37th International Workshop on Description Logics (DL 2024). CEUR-WS.org. Fulltekst i vitenarkiv
• Karlsen, Leif Harald & Giese, Martin (2018). A simple, General and Efficient Representation of Qualitative Spatial Information; An Approach Based on Bintrees. Series of dissertations submitted ti the Faculty of Mathematics and Natural Sciences, University of Oslo. Fulltekst i vitenarkiv
• Karlsen, Leif Harald & Giese, Martin (2017). An Efficient Representation of Qualitative Spatial Information using Bintrees. Department of Informatics, University of Oslo. ISSN 9788273684257. Fulltekst i vitenarkiv Vis sammendrag

  We present a representation of spatial data that supports answering of qualitative queries (involving e.g. containment and overlap), using less time than numerical computations on coordinates, and less space than explicitly storing the relations. The representation is based on the well-known bintree indexing data structure, which we refine to provide exact answers instead of approximations. We have imple- mented the method, and tested it on several real-world datasets with promising results.

• Karlsen, Leif Harald & Giese, Martin (2017). Qualitatively Correct Bintrees With Roles. Department of Informatics, University of Oslo. ISSN 9788273684325. Fulltekst i vitenarkiv Vis sammendrag

  The concrete problem this paper addresses is the following: Given a set of objects with a spatial interpretation and a set of qualitative relations, construct a bintree representation that returns the same answers to queries with the given relations over the spatial objects. We have previously constructed both theory [8] and an implementation [9] for constructing such qualitatively correct bintrees, with promising results. However, our previous work has been restricted to the construction of bintree-representations that are correct only w.r.t. part-of and overlaps relationships. In this paper we will extend the theoretical foundation to allow for representations that are correct with respect to a more expressive set of relations.

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