25 results on '"Steen, Alexander"'
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2. An Extensible Logic Embedding Tool for Lightweight Non-Classical Reasoning
- Author
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Steen, Alexander
- Subjects
FOS: Computer and information sciences ,Computer Science - Logic in Computer Science ,Artificial Intelligence (cs.AI) ,TheoryofComputation_MATHEMATICALLOGICANDFORMALLANGUAGES ,Computer Science - Artificial Intelligence ,68T30 (Primary) 68T27, 03B45, 03B60, 03B16 (Secondary) ,Logic in Computer Science (cs.LO) - Abstract
The logic embedding tool provides a procedural encoding for non-classical reasoning problems into classical higher-order logic. It is extensible and can support an increasing number of different non-classical logics as reasoning targets. When used as a pre-processor or library for higher-order theorem provers, the tool admits off-the-shelf automation for logics for which otherwise few to none provers are currently available., 10 pages, 1 figure, 1 table
- Published
- 2022
3. Automated reasoning in non-classical logics in the TPTP world
- Author
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Steen, Alexander, David Fuenmayor, Gleißner, Tobias, Sutcliffe, Geoff, and Christoph Benzmüller
- Subjects
FOS: Computer and information sciences ,Artificial Intelligence (cs.AI) ,Computer Science - Artificial Intelligence ,TPTP World ,68T30 (Primary) 68T27, 03B45, 03B60 (Secondary) ,automated reasoning ,non-classical logics - Abstract
Non-classical logics are used in a wide spectrum of disciplines, including artificial intelligence, computer science, mathematics, and philosophy. The de-facto standard infrastructure for automated theorem proving, the TPTP World, currently supports only classical logics. Similar standards for non-classical logic reasoning do not exist (yet). This hampers practical development of reasoning systems, and limits their interoperability and application. This paper describes the latest extension of the TPTP World, which provides languages and infrastructure for reasoning in non-classical logics. The extensions integrate seamlessly with the existing TPTP World., Comment: 21 pages
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- 2022
- Full Text
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4. Solving QMLTP Problems by Translation to Higher-order Logic
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Steen, Alexander, Sutcliffe, Geoff, Scholl, Tobias, and Benzmüller, Christoph
- Subjects
FOS: Computer and information sciences ,Computer Science - Logic in Computer Science ,I.2.3 ,Artificial Intelligence (cs.AI) ,Computer Science - Artificial Intelligence ,F.4.1 ,Logic in Computer Science (cs.LO) - Abstract
This paper describes an evaluation of Automated Theorem Proving (ATP) systems on problems taken from the QMLTP library of first-order modal logic problems. Principally, the problems are translated to higher-order logic in the TPTP language using an embedding approach, and solved using higher-order logic ATP systems. Additionally, the results from native modal logic ATP systems are considered, and compared with those from the embedding approach. The findings are that the embedding process is reliable and successful, the choice of backend ATP system can significantly impact the performance of the embedding approach, native modal logic ATP systems outperform the embedding approach, and the embedding approach can cope with a wider range modal logics than the native modal systems considered., Comment: 17 pages, 1 figure
- Published
- 2022
- Full Text
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5. Bridging between LegalRuleML and TPTP for Automated Normative Reasoning (extended version)
- Author
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Steen, Alexander and Fuenmayor, David
- Subjects
FOS: Computer and information sciences ,Artificial Intelligence (cs.AI) ,Computer Science - Artificial Intelligence ,68T30 (Primary) 68T27, 03B45, 03B60, 03B16 (Secondary) - Abstract
LegalRuleML is a comprehensive XML-based representation framework for modeling and exchanging normative rules. The TPTP input and output formats, on the other hand, are general-purpose standards for the interaction with automated reasoning systems. In this paper we provide a bridge between the two communities by (i) defining a logic-pluralistic normative reasoning language based on the TPTP format, (ii) providing a translation scheme between relevant fragments of LegalRuleML and this language, and (iii) proposing a flexible architecture for automated normative reasoning based on this translation. We exemplarily instantiate and demonstrate the approach with three different normative logics., Comment: 19 pages, 1 figure
- Published
- 2022
- Full Text
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6. Goal-Directed Decision Procedures for Input/Output Logics
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Steen, Alexander and Fonds National de la Recherche - FnR [sponsor]
- Subjects
Computer science [C05] [Engineering, computing & technology] ,Deontic logic ,TheoryofComputation_MATHEMATICALLOGICANDFORMALLANGUAGES ,normative reasoning ,Automated Reasoning ,Computer Science::Logic in Computer Science ,Sciences informatiques [C05] [Ingénierie, informatique & technologie] - Abstract
Input/Output (I/O) logics address the abstract study of conditional norms. Here, norms are represented as pairs of formulas instead of statements that themselves carry truth-values. I/O logics have been studied thoroughly in the past, including further applications and refinements. In this paper, a class of automated reasoning procedures is presented that, given a set of norms and a concrete situation, decide whether a specific state of affairs is obligatory according to the output operations of I/O logics. The procedures are parametric in the underlying logical formalism and can be instantiated with different classical objects logics, such as propositional logic or first-order logic. The procedures are shown to be correct, and a proof-of-concept implementation for propositional I/O logics is surveyed.
- Published
- 2021
7. A Formalisation of Abstract Argumentation in Higher-Order Logic
- Author
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Steen, Alexander, Fuenmayor Pelaez, David, and Fonds National de la Recherche - FnR [sponsor]
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Computer science [C05] [Engineering, computing & technology] ,FOS: Computer and information sciences ,Computer Science - Logic in Computer Science ,I.2.3 ,I.2.4 ,68T01 68T27 68T30 03B16 03B35 03B70 ,Higher-Order Logic ,Computer Science - Artificial Intelligence ,F.4.1 ,Automated Theorem Proving ,Isabelle/HOL ,Sciences informatiques [C05] [Ingénierie, informatique & technologie] ,Logic in Computer Science (cs.LO) ,Artificial Intelligence (cs.AI) ,abstract argumentation - Abstract
We present an approach for representing abstract argumentation frameworks based on an encoding into classical higher-order logic. This provides a uniform framework for computer-assisted assessment of abstract argumentation frameworks using interactive and automated reasoning tools. This enables the formal analysis and verification of meta-theoretical properties as well as the flexible generation of extensions and labellings with respect to well-known argumentation semantics., Comment: 33 pages, 8 figures; submitted article
- Published
- 2021
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8. A Flexible Approach to Argumentation Framework Analysis using Theorem Proving
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Fuenmayor Pelaez, David, Steen, Alexander, and Fonds National de la Recherche - FnR [sponsor]
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Computer science [C05] [Engineering, computing & technology] ,Sciences informatiques [C05] [Ingénierie, informatique & technologie] - Abstract
Argumentation frameworks constitute the central concept of argumentation theory of Dung. In this paper we present a novel and flexible approach of analyzing argumen- tation frameworks and their semantics based on an encoding into extensional type theory (classical higher-order logic). This representation enables the use of a wide range of interactive and automated higher-order reasoning tools for assessing argu- mentation frameworks. This includes the generation of labellings (and extensions), the assessment of meta-theoretic properties, the conduction of interactive empirical experiments, and the flexible analysis of argumentation frameworks with interpreted arguments.
- Published
- 2021
9. LogiKEy Workbench: Deontic Logics, Logic Combinations and Expressive Ethical and Legal Reasoning (Isabelle/HOL Dataset)
- Author
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Benzmüller, Christoph, Farjami, Ali, Fuenmayor, David, Meder, Paul, Parent, Xavier, Steen, Alexander, van der Torre, Leendert, and Zahoransky, Valeria
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Computer science [C05] [Engineering, computing & technology] ,000 Informatik, Informationswissenschaft, allgemeine Werke::000 Informatik, Wissen, Systeme::000 Informatik, Informationswissenschaft, allgemeine Werke ,Higher-Order Logic ,lcsh:Computer applications to medicine. Medical informatics ,Knowledge representation and reasoning ,Sciences informatiques [C05] [Ingénierie, informatique & technologie] ,Model finding ,Normative reasoning ,TheoryofComputation_MATHEMATICALLOGICANDFORMALLANGUAGES ,Normative systems ,Trustworthy and responsible AI ,Automated theorem proving ,lcsh:R858-859.7 ,Semantical embedding ,Higher-order logic ,lcsh:Science (General) ,Data Article ,lcsh:Q1-390 - Abstract
The LogiKEy workbench and dataset for ethical and legal reasoning is presented. This workbench simultaneously supports development, experimentation, assessment and deployment of formal logics and ethical and legal theories at different conceptual layers. More concretely, it comprises, in form of a dataset (Isabelle/HOL theory files), formal encodings of multiple deontic logics, logic combinations, deontic paradoxes and normative theories in the higher-order proof assistant system Isabelle/HOL. The data were acquired through application of the LogiKEy methodology, which supports experimentation with different normative theories, in different application scenarios, and which is not tied to specific logics or logic combinations. Our workbench consolidates related research contributions of the authors and it may serve as a starting point for further studies and experiments in flexible and expressive ethical and legal reasoning. It may also support hands-on teaching of non-trivial logic formalisms in lecture courses and tutorials. The LogiKEy methodology and framework is discussed in more detail in the companion research article titled "Designing Normative Theories for Ethical and Legal Reasoning: LogiKEy Framework, Methodology, and Tool Support" [5].
- Published
- 2020
10. On Reductions of Hintikka Sets for Higher-Order Logic
- Author
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Steen, Alexander and Benzmüller, Christoph
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Computer science [C05] [Engineering, computing & technology] ,FOS: Computer and information sciences ,Computer Science - Logic in Computer Science ,I.2.3 ,Higher-Order Logic ,Computer Science - Artificial Intelligence ,Mathematics - Logic ,03B35, 68T15 ,Sciences informatiques [C05] [Ingénierie, informatique & technologie] ,Semantics ,Logic in Computer Science (cs.LO) ,Artificial Intelligence (cs.AI) ,F.4.1 ,FOS: Mathematics ,Logic (math.LO) ,Abstract Consistency - Abstract
Steen's (2018) Hintikka set properties for Church's type theory based on primitive equality are reduced to the Hintikka set properties of Brown (2007). Using this reduction, a model existence theorem for Steen's properties is derived., Comment: 10 pages; improved version
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- 2020
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11. The NAI Suite -- Drafting and Reasoning over Legal Texts
- Author
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Libal, Tomer and Steen, Alexander
- Subjects
FOS: Computer and information sciences ,Artificial Intelligence (cs.AI) ,Computer Science - Artificial Intelligence - Abstract
A prototype for automated reasoning over legal texts, called NAI, is presented. As an input, NAI accepts formalized logical representations of such legal texts that can be created and curated using an integrated annotation interface. The prototype supports automated reasoning over the given text representation and multiple quality assurance procedures. The pragmatics of the NAI suite as well its feasibility in practical applications is studied on a fragment of the Smoking Prohibition (Children in Motor Vehicles) (Scotland) Act 2016 of the Scottish Parliament.
- Published
- 2019
12. Proceedings of the Deduktionstreffen 2019
- Author
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Schon, Claudia and Steen, Alexander
- Subjects
Computer science [C05] [Engineering, computing & technology] ,Sciences informatiques [C05] [Ingénierie, informatique & technologie] - Abstract
The annual meeting Deduktionstreffen is the prime activity of the Special Interest Group on Deduction Systems (FG DedSys) of the AI Section of the German Society for Informatics (GI-FBKI). It is a meeting with a familiar, friendly atmosphere, where everyone interested in deduction can report on their work in an informal setting.
- Published
- 2019
13. Extensional Paramodulation for Higher-Order Logic and its Effective Implementation Leo-III
- Author
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Steen, Alexander and Dahlem Center for Machine Learning and Robotics, Freie Universität Berlin [research center]
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Computer science [C05] [Engineering, computing & technology] ,Sciences informatiques [C05] [Ingénierie, informatique & technologie] - Published
- 2018
14. Mechanical temperature control of oil based heat storage
- Author
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Sjøgren, Oskar Stadaas, Steen, Alexander Bjåen, Nydal, Ole Jørgen, and Næss, Erling
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Produktutvikling og produksjon, Industriell prosessteknikk - Abstract
A cooking application and a mechanical temperature controller based on the thermal expansion of sunflower oil were constructed and tested. Both components are parts of a solar cooking system, storing energy in an oil-based rock bed, made in the project work "Solar Heat Storage In Oil Based Rock Bed". This thesis is a part of a network project with universities in Mozambique, Uganda, Ethiopia and Tanzania, and focuses on energy supply to rural and off-grid communities in Africa. The motivation is to store energy from renewable energy sources, for later to be used in food preparations after sunset. Moreover, a simple system is desired, to make the operation and maintenance as easy as possible. This functional mechanical temperature controller will provide more flexibility to the solar cooking system, making it feasible for more settings than the system constructed in the project work. A mechanical temperature controller was made from two components; a piston actuator and a sliding valve. Three piston actuator designs were constructed and tested, all of which were connected to a closed pipe system with a copper coil filled with sunflower oil. The copper coil was submerged in a container holding sunflower oil and a heating element. During heating, the sunflower oil inside the copper coil expands due to the temperature change, giving a displacement of the piston actuator. The displacement is the motion which controls the sliding valve. Three sliding valve designs were constructed and tested, all utilising the linear motion from the piston actuator. The valve determines the flow direction, either towards the heat storage or for further heating, depending on the flow temperature. The valve can be used with and without circulation of the oil. Leaks caused problems throughout the production and tests of the components. A functional sliding valve was successfully constructed, whereas the first piston actuators were faulty due to leaks. The accuracy of the piston actuators made in the workshop at NTNU was not satisfying. Therefore, prefabricated pneumatic pistons were acquired. Preliminary tests gave promising results. Nevertheless, tests of the full system were not conducted due to the limited time. Two designs for a cooking application were made using a practical and a theoretical approach. The practical approach design was constructed and tested. The cooking effect was promising compared to other solar cookers, but it needs to be upscaled and further improved in order to deliver energy in the same order of magnitude as already established solar cookers. A test setup of the solar cooking system was made at Makerere University, Kampala, Uganda. The fill valve from the co-project was used as the temperature controller. Demonstrations proved the system made at NTNU is capable of being reproduced locally and is a concept suited for further development.
- Published
- 2018
15. The Higher-Order Prover Leo-III (Extended Version)
- Author
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Steen, Alexander and Benzmüller, Christoph
- Subjects
FOS: Computer and information sciences ,Computer Science - Logic in Computer Science ,I.2.3 ,I.2.4 ,Computer Science - Artificial Intelligence ,F.4.1 ,Mathematics - Logic ,Logic in Computer Science (cs.LO) ,TheoryofComputation_MATHEMATICALLOGICANDFORMALLANGUAGES ,Artificial Intelligence (cs.AI) ,03B35, 03B15, 03B45, 68T15, 68T27, 68T30:, 03Bxx ,TheoryofComputation_LOGICSANDMEANINGSOFPROGRAMS ,FOS: Mathematics ,Logic (math.LO) - Abstract
The automated theorem prover Leo-III for classical higher-order logic with Henkin semantics and choice is presented. Leo-III is based on extensional higher-order paramodulation and accepts every common TPTP dialect (FOF, TFF, THF), including their recent extensions to rank-1 polymorphism (TF1, TH1). In addition, the prover natively supports almost every normal higher-order modal logic. Leo-III cooperates with first-order reasoning tools using translations to many-sorted first-order logic and produces verifiable proof certificates. The prover is evaluated on heterogeneous benchmark sets., Comment: 13 pages (this is an extended version of the IJCAR 2018 paper)
- Published
- 2018
- Full Text
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16. The Virtues of Automated Theorem Proving in Metaphysics --- A Case Study: E. J. Lowe's Modal Ontological Argument
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Fuenmayor, David, Benzmüller, Christoph, Steen, Alexander, and Wsinieswki, Max
- Subjects
Computer science [C05] [Engineering, computing & technology] ,computational metaphysics ,higher-order automated theorem proving ,Religion & theology [A09] [Arts & humanities] ,Philosophy & ethics [A08] [Arts & humanities] ,Sciences informatiques [C05] [Ingénierie, informatique & technologie] ,Philosophie & éthique [A08] [Arts & sciences humaines] ,Religion & théologie [A09] [Arts & sciences humaines] ,modal logic - Published
- 2017
17. Agent-Based HOL Reasoning
- Author
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Steen, Alexander, Wisniewski, Max, and Benzmüller, Christoph
- Subjects
Computer science [C05] [Engineering, computing & technology] ,Automated Reasoning ,LEO Prover ,Higher Order Logic ,Sciences informatiques [C05] [Ingénierie, informatique & technologie] - Published
- 2016
18. Hochschuldidaktik der Informatik
- Author
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Dennert-Möller, Elisabeth, Garmann, Robert, Kujath, Bertold, Zscheyge, Oliver, Weicker, Karsten, Böhne, Sebastian, Knobelsdorf, Maria, Kreitz, Christoph (Prof. Dr.), Steen, Alexander, Wisniewski, Max, Benzmüller, Christoph, Gebhardt, Kai, Ehlenz, Matthias, Bergner, Nadine, and Schroeder, Ulrik (Univ.-Prof. Dr.-Ing.)
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Institut für Informatik und Computational Science ,ddc:004 - Abstract
Die 7. Fachtagung für Hochschuldidaktik, die 2016 erneut mit der DeLFI E-Learning Fachtagung Informatik stattfand, setzte das erfolgreiche Modell einer Tagung fort, die sich mit hochschuldidaktischen Fragen und der Gestaltung von Studiengängen der Informatik beschäftigt. Thema der Tagung waren alle Fragen, die sich der Vermittlung von Informatikgegenständen im Hochschulbereich widmen. Dazu gehörten u.a.: • fachdidaktische Konzepte der Vermittlung einzelner Informatikgegenstände • methodische Lösungen, wie spezielle Lehr- und Lernformen, Durchführungskonzepte • empirische Ergebnisse und Vergleichsstudien • E-Learning-Ansätze, wenn sie ein erkennbares didaktisches Konzept verfolgen • Studienkonzepte und Curricula, organisatorische Fragen, wie Gewinnung von Studierenden, Studieneingangsphase, Abbrecher. Die Fachtagung widmete sich ausgewählten Fragestellungen dieses Themenkomplexes, die durch Vorträge ausgewiesener Experten, durch eingereichte Beiträge und durch Präsentationen und Poster intensiv behandelt wurden. Unser besonderer Dank gilt dem Programmkomitee und den hier nicht genannten Helfern für ihren Einsatz bei der Vorbereitung und Durchführung der Tagung.
- Published
- 2016
19. Usage of Theorem Provers in Teaching
- Author
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Steen, Alexander, Wisniewski, Max, and Benzmüller, Christoph
- Subjects
Computer science [C05] [Engineering, computing & technology] ,Computational Metaphysics ,Logic ,Institut für Informatik und Computational Science ,Interactive Theorem Proving ,ddc:004 ,Sciences informatiques [C05] [Ingénierie, informatique & technologie] - Abstract
Dieser Beitrag diskutiert den Einsatz von interaktiven und automatischen Theorembeweisern in der universitären Lehre. Moderne Theorembeweiser scheinen geeignet zur Implementierung des dialogischen Lernens und als E-Assessment-Werkzeug in der Logikausbilding. Exemplarisch skizzieren wir ein innovaties Lehrprojekt zum Thema „Komputationale Metaphysik“, in dem die zuvor genannten Werkzeuge eingesetzt werden.
- Published
- 2016
20. There Is No Best Beta-Normalization Strategy for Higher-Order Reasoners
- Author
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Steen, Alexander and Benzmüller, Christoph
- Subjects
Computer science [C05] [Engineering, computing & technology] ,Automated Reasoning ,LEO Prover ,Higher Order Logic ,Sciences informatiques [C05] [Ingénierie, informatique & technologie] ,Lambda-Calculus - Published
- 2015
21. Computational Metaphysics
- Author
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Benzmüller, Christoph, Wisniewski, Max, and Steen, Alexander
- Subjects
Computer science [C05] [Engineering, computing & technology] ,Computational Metaphysics ,Philosophy & ethics [A08] [Arts & humanities] ,Sciences informatiques [C05] [Ingénierie, informatique & technologie] ,Philosophie & éthique [A08] [Arts & sciences humaines] - Published
- 2015
22. Efficient Data Structures for Automated Theorem Proving in Expressive Higher-Order Logics
- Author
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Steen, Alexander, Benzmüller, Christoph [superviser], and Kyas, Marcel [member of the jury]
- Subjects
Computer science [C05] [Engineering, computing & technology] ,Data structures ,Higher-Order Logic ,Automated Theorem Proving ,Sciences informatiques [C05] [Ingénierie, informatique & technologie] - Abstract
Church's Simple Theory of Types (STT), also referred to as classical higher-order logik, is an elegant and expressive formal system built on top of the simply typed λ-calculus. Its mechanisms of explicit binding and quantification over arbitrary sets and functions allow the representation of complex mathematical concepts and formulae in a concise and unambiguous manner. Higher-order automated theorem proving (ATP) has recently made major progress and several sophisticated ATP systems for higher-order logic have been developed, including Satallax, Osabelle/HOL and LEO-II. Still, higher-order theorem proving is not as mature as its first-order counterpart, and robust implementation techniques for efficient data structures are scarce. In this thesis, a higher-order term representation based upon the polymorphically typed λ-calculus is presented. This term representation employs spine notation, explicit substitutions and perfect term sharing for efficient term traversal, fast β-normalization and reuse of already constructed terms, respectively. An evaluation of the term representation is performed on the basis of a heterogeneous benchmark set. It shows that while the presented term data structure performs quite well in general, the normalization results indicate that a context dependent choice of reduction strategies is beneficial. A term indexing data structure for fast term retrieval based on various low-level criteria is presented and discussed. It supports symbol-based term retrieval, indexing of terms via structural properties, and subterm indexing.
- Published
- 2014
23. The Leo-III Project
- Author
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Wisniewski, Max, Steen, Alexander, and Benzmüller, Christoph
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- 2014
- Full Text
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24. 3D Visualization for Pre-operative Planning of Orthopedic Surgery
- Author
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Steen, Alexander and Widegren, Marcus
- Subjects
thr ,sectra ,Media and Communication Technology ,Medieteknik ,medical ,visualization ,3d ,total hip replacement - Abstract
This report presents a master thesis on 3D visualization for pre-operation planning of orthopedic surgery done for Sectra Medical Systems AB. The focus is on visualizing clinically relevant data for planning a Total Hip Replacement (THR). The thesis includes a pre-study and the implementation of a prototype using the Sectra IDS7 workstation.
- Published
- 2013
25. Knowledge Elicitation within the Knowledge Base Paradigm: Disentangling Domain Knowledge from Decision Making in Industrial Applications
- Author
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Deryck, Marjolein, Vennekens, Joost, Soylu, Ahmet, Moschoyiannis, Sotiris, Governatori, Guido, Simkus, Mantas, Stefaneas, Petros, Steen, Alexander, and Giurca, Adrian
- Abstract
ispartof: CEUR Workshop Proceedings vol:2438 ispartof: RuleML + RR 2019 location:Bolzano status: Published online
- Published
- 2019
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