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Computer Science and Engineering Faculty Publications

2005

Articles 1 - 25 of 25

Full-Text Articles in Physical Sciences and Mathematics

Modeling Fuzzy Rules With Description Logics, Sudhir Agarwal, Pascal Hitzler Nov 2005

Modeling Fuzzy Rules With Description Logics, Sudhir Agarwal, Pascal Hitzler

Computer Science and Engineering Faculty Publications

In real application scenarios, input data and knowledge is often vague. Likewise, it is often the case that exact reasoning over data is impossible due to complex dependencies between input data and target outputs. For practical applications, however, good approximations often suffice, and efficient calculation of an approximate answer is often preferable over complex processing which may take a long time to come up with an exact answer. Fuzzy logic supports both features by providing fuzzy membership functions and fuzzy IF-THEN rule bases. In this paper, we show how fuzzy membership functions and fuzzy rules can be modeled by means …

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The Screech Owl Reasoner - Scalable Approximate Abox Reasoning With Owl, Pascal Hitzler, Denny Vrandecic Nov 2005

The Screech Owl Reasoner - Scalable Approximate Abox Reasoning With Owl, Pascal Hitzler, Denny Vrandecic

Computer Science and Engineering Faculty Publications

We present a preliminary version of the approximate OWL reasoning system SCREECH. It builds on the KAON2 system and performs OWL ABox reasoning in an approximate manner. It trades soundness of reasoning for efficiency, with resulting polynomial worst-case data complexity. It has been developed for use in time-critical applications where quick response time is more important than a full guarantee of correctness of answers. The theoretical background for the system is explained in [Hitzler and Vrandecic, 2005] and is being presented at the conference.

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Dlp Isn't So Bad After All, Peter Haase, Markus Krotzsch, York Sure, Rudi Studer, Pascal Hitzler Nov 2005

Dlp Isn't So Bad After All, Peter Haase, Markus Krotzsch, York Sure, Rudi Studer, Pascal Hitzler

Computer Science and Engineering Faculty Publications

We discuss some of the recent controversies concerning the DLP fragment of OWL. We argue that it is a meaningful fragment and can serve as a basic interoperability layer between OWL and logic programming-based ontology languages.

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Extracting Reduced Logic Programs From Artificial Neural Networks, Jens Lehmann, Sebastian Bader, Pascal Hitzler Aug 2005

Extracting Reduced Logic Programs From Artificial Neural Networks, Jens Lehmann, Sebastian Bader, Pascal Hitzler

Computer Science and Engineering Faculty Publications

Artificial neural networks can be trained to perform excellently in many application areas. While they can learn from raw data to solve sophisticated recognition and analysis problems, the acquired knowledge remains hidden within the network architecture and is not readily accessible for analysis or further use: Trained networks are black boxes. Recent research efforts therefore investigate the possibility to extract symbolic knowledge from trained networks, in order to analyze, validate, and reuse the structural insights gained implicitly during the training process. In this paper, we will study how knowledge in form of propositional logic programs can be obtained in such …

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Integrating First-Order Logic Programs And Connectionist Systems - A Constructive Approach, Sebastian Bader, Andreas Witzel, Pascal Hitzler Aug 2005

Integrating First-Order Logic Programs And Connectionist Systems - A Constructive Approach, Sebastian Bader, Andreas Witzel, Pascal Hitzler

Computer Science and Engineering Faculty Publications

Significant advances have recently been made concerning the integration of symbolic knowledge representation with artificial neural networks (also called connectionist systems). However, while the integration with propositional paradigms has resulted in applicable systems, the case of first-order knowledge representation has so far hardly proceeded beyond theoretical studies which prove the existence of connectionist systems for approximating first-order logic programs up to any chosen precision. Advances were hindered severely by the lack of concrete algorithms for obtaining the approximating networks which were known to exist: the corresponding proofs are not constructive in that they do not yield concrete methods for building …

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Ontology Learning As A Use-Case For Neural-Symbolic Integration, Pascal Hitzler, Sebastian Bader, Artur Garcez Aug 2005

Ontology Learning As A Use-Case For Neural-Symbolic Integration, Pascal Hitzler, Sebastian Bader, Artur Garcez

Computer Science and Engineering Faculty Publications

We argue that the field of neural-symbolic integration is in need of identifying application scenarios for guiding further research. We furthermore argue that ontology learning - as occurring in the context of semantic technologies - provides such an application scenario with potential for success and high impact on neural-symbolic integration.

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Faster Owl Using Split Programs, Denny Vrandecic, Pascal Hitzler Jul 2005

Faster Owl Using Split Programs, Denny Vrandecic, Pascal Hitzler

Computer Science and Engineering Faculty Publications

Knowledge representation and reasoning on the Semantic Web is done by means of ontologies. While the quest for suitable ontology languages is still ongoing, OWL [5] has been established as a core standard. It comes in three flavours, as OWL Full, OWL DL and OWL Lite, where OWL Full contains OWL DL, which in turn contains OWL Lite. The latter two coincide semantically with certain description logics and can thus be considered fragments of first-order predicate logic.

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Morphisms In Context, Markus Krotzsch, Guo-Qiang Zhang, Pascal Hitzler Jul 2005

Morphisms In Context, Markus Krotzsch, Guo-Qiang Zhang, Pascal Hitzler

Computer Science and Engineering Faculty Publications

Morphisms constitute a general tool for modelling complex relationships between mathematical objects in a disciplined fashion. In Formal Concept Analysis (FCA), morphisms can be used for the study of structural properties of knowledge represented in formal contexts, with applications to data transformation and merging. In this paper we present a comprehensive treatment of some of the most important morphisms in FCA and their relationships, including dual bonds, scale measures, infomorphisms, and their respective relations to Galois connections. We summarize our results in a concept lattice that cumulates the relationships among the considered morphisms. The purpose of this work is to …

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Description Logic Programs: A Practical Choice For The Modelling Of Ontologies, Rudi Studer, York Sure, Pascal Hitzler Jun 2005

Description Logic Programs: A Practical Choice For The Modelling Of Ontologies, Rudi Studer, York Sure, Pascal Hitzler

Computer Science and Engineering Faculty Publications

Knowledge representation using ontologies constitutes the heart of semantic technologies. Despite successful standardization efforts by the W3C, however, there are still numerous different ontology representation languages being used, and interoperability between them is in general not given. The problem is aggrevated by the fact that current standards lay foundations only and are well-known to be insufficient for the modelling of finer details. Thus, a plethora of extensions of the basic languages is being proposed, rendering the picture of ontology representation languages to be chaotic, to say the least. While semantic technologies start to become applicable and are being applied in …

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Towards A Systematic Account Of Different Semantics For Logic Programs, Pascal Hitzler Jun 2005

Towards A Systematic Account Of Different Semantics For Logic Programs, Pascal Hitzler

Computer Science and Engineering Faculty Publications

A new methodology has been proposed which allows one to derive uniform characterizations of different declarative semantics for logic programs with negation. One result from this work is that the well-founded semantics can formally be understood as a stratified version of the Fitting (or Kripke–Kleene) semantics. The constructions leading to this result, however, show a certain asymmetry which is not readily understood. We study this situation here with the result that we obtain a coherent picture of relations between different semantics for normal logic programs.

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Integrated Visualization And Analysis Of A Pig's Cardiovascular System, Joerg Meyer, Thomas Wischgoll, Elke Moritz Jun 2005

Integrated Visualization And Analysis Of A Pig's Cardiovascular System, Joerg Meyer, Thomas Wischgoll, Elke Moritz

Computer Science and Engineering Faculty Publications

No abstract provided.

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Integrating Semantic Web Services For Mobile Access, Anupriya Ankolekar, Pascal Hitzler, Holger Lewen, Daniel Oberle, Rudi Studer Jun 2005

Integrating Semantic Web Services For Mobile Access, Anupriya Ankolekar, Pascal Hitzler, Holger Lewen, Daniel Oberle, Rudi Studer

Computer Science and Engineering Faculty Publications

We present our work in integrating Semantic Web services for access via mobile devices. We have developed a system, the WebServiceAccessComponent, that transforms a user request for a service on a mobile device, to a Web service request and then selects a matching service from the existing Web services of the Deutsche Telekom, which provide navigational and weather information. In this poster, we present the requirements and design of the WebServiceAccessComponent.

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Bridging The Paradigm Gap With Rules For Owl, Jurgen Angele, Boris Motik, Rudi Studer, Pascal Hitzler Apr 2005

Bridging The Paradigm Gap With Rules For Owl, Jurgen Angele, Boris Motik, Rudi Studer, Pascal Hitzler

Computer Science and Engineering Faculty Publications

Accelerated by the vision of the semantic web, semantic technologies have recently made significant advances. The underlying methods and paradigms are already being transferred to adjacent areas of research in artificial intelligence, knowledge management, and elsewhere. Textbooks explaining the foundations have appeared. Large national and international projects on the topic are under way.

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Fly Through A Pig's Heart: An Educational Computer Game, Thomas Wischgoll, Joerg Meyer Apr 2005

Fly Through A Pig's Heart: An Educational Computer Game, Thomas Wischgoll, Joerg Meyer

Computer Science and Engineering Faculty Publications

No abstract provided.

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Specification Of A Common Framework For Characterizing Alignment, Paolo Bouquet, Marc Ehrig, Jerome Euzenat, Enrico Franconi, Pascal Hitzler, Markus Krotzsch, Luciano Serafini, Giorgos Stamu, York Sure, Sergio Tessaris Feb 2005

Specification Of A Common Framework For Characterizing Alignment, Paolo Bouquet, Marc Ehrig, Jerome Euzenat, Enrico Franconi, Pascal Hitzler, Markus Krotzsch, Luciano Serafini, Giorgos Stamu, York Sure, Sergio Tessaris

Computer Science and Engineering Faculty Publications

Definition of a common framework for characterizing alignment of heterogeneous information. This report describes various approaches towards this goal and shows the relations between them. It also provides a description of the alignment sructure and process.

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A Uniform Approach To Logic Programming Semantics, Pascal Hitzler, Matthias Wendt Jan 2005

A Uniform Approach To Logic Programming Semantics, Pascal Hitzler, Matthias Wendt

Computer Science and Engineering Faculty Publications

Part of the theory of programming and nonymonotonic reasoning concerns the study of fixed-point semantics for these paradigms. Several different semantics have been proposed during the last two decades, and some have been more successful and acknowledged than others. The rationales behind those various semantics have been manifold, depending on one's point of view, which may be that of a programmer or inspired by commonsense reasoning, and consequently the constructions which lead to these semantics are technically very diverse, and the exact relationships between them have not yet been fully understood. In this paper, we present a conceptually new method, …

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Level Mapping Characterizations Of Selector-Generated Models For Logic Programs, Sibylle Schwarz, Pascal Hitzler Jan 2005

Level Mapping Characterizations Of Selector-Generated Models For Logic Programs, Sibylle Schwarz, Pascal Hitzler

Computer Science and Engineering Faculty Publications

Assigning semantics to logic programs via selector generated models (Schwarz 2002/2003) extends several semantics, like the stable, the inflationary, and the stable generated semantics, to programs with arbitrary formulae in rule heads and bodies. We study this approach by means of a unifying framework for characterizing different logic programming semantics using level mappings (Hitzler and Wendt 200x, Hitzler 2003), thereby supporting the claim that this framework is very flexible and applicable to very diversely defined semantics.

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Dlpconvert: Converting Owl Dlp Statements To Logic Programs, Boris Motik, Denny Vrandecic, Pascal Hitzler, York Sure, Rudi Studer Jan 2005

Dlpconvert: Converting Owl Dlp Statements To Logic Programs, Boris Motik, Denny Vrandecic, Pascal Hitzler, York Sure, Rudi Studer

Computer Science and Engineering Faculty Publications

In the past few years, the W3C has been establishing standards for the fundamental building blocks of the Semantic Web. With RDF a common data model has been provided. A major step was the introduction of the ontology definition languages RDFS—offering very basic semantics—and the Web Ontology Language OWL As these standards are still very new, only a limited support of tools for inferencing and querying exists. Still, the availability of such tools will be crucial for the development of the Semantic Web.

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Visualizing Very Large-Scale Vascular Structures Interactively, Thomas Wischgoll, Joerg Meyer, Benjamin Kaimovitz, Yoram Lanir, Ghassan S. Kassab Jan 2005

Visualizing Very Large-Scale Vascular Structures Interactively, Thomas Wischgoll, Joerg Meyer, Benjamin Kaimovitz, Yoram Lanir, Ghassan S. Kassab

Computer Science and Engineering Faculty Publications

No abstract provided.

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The Semantic Web In One Day, York Sure, Pascal Hitzler, Andreas Eberhart, Rudi Studer Jan 2005

The Semantic Web In One Day, York Sure, Pascal Hitzler, Andreas Eberhart, Rudi Studer

Computer Science and Engineering Faculty Publications

To gain momentum, technologies for building private semantic Webs or parts of the World Wide semantic Web must become a commodity and easy to integrate. To determine just how far semantic Web technologies have come, we wanted to create a snapshot of what you could do by applying and assembling existing semantic Web technologies - in one day.

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An Explorational Exhibit Of A Pig's Heart, Thomas Wischgoll, Joerg Meyer Jan 2005

An Explorational Exhibit Of A Pig's Heart, Thomas Wischgoll, Joerg Meyer

Computer Science and Engineering Faculty Publications

No abstract provided.

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The Interior Of A Pig's Heart: A Museum Exhibit, Thomas Wischgoll, Joerg Meyer Jan 2005

The Interior Of A Pig's Heart: A Museum Exhibit, Thomas Wischgoll, Joerg Meyer

Computer Science and Engineering Faculty Publications

Coronary heart diseases (CHD) are one of the primary causes of deaths in the United States. It is commonly accepted that certain factors, such as a cholesterol high diet, increase the risk of coronary heart diseases. As a consequence, people should be educated to adhere a diet low in low-density lipoprotein (LDL or bad cholesterol). ln order for children to become familiar with these facts, educational computer games can be employed to raise some awareness. This poster describes an educational museum exhibit that serves this purpose. ln a game-like environment, children can practice their navigation skills, while learning about the …

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Dlp - An Introduction, Denny Vrandecic, Pascal Hitzler, Rudi Studer Jan 2005

Dlp - An Introduction, Denny Vrandecic, Pascal Hitzler, Rudi Studer

Computer Science and Engineering Faculty Publications

DLP - Description Logic Programs - is the name for the common language that is able to integrate knowledge bases described in Description Logic with Logic Programs. In this introduction, we offer a very short overview of DLP, the motivation for it, the benefits it offers and how to use it.

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Methods For Approximate Reasoning, Perry Groot, Pascal Hitzler, Ian Horrocks, Boris Motik, Jeff Z. Pan, Heiner Stuckenschmidt, Daniele Turi, Holger Wache Jan 2005

Methods For Approximate Reasoning, Perry Groot, Pascal Hitzler, Ian Horrocks, Boris Motik, Jeff Z. Pan, Heiner Stuckenschmidt, Daniele Turi, Holger Wache

Computer Science and Engineering Faculty Publications

This deliverable shows examples about approximating symbolic inference engines in a Semantic Web environment. Approaches of language weakening, knowledge compilation, and approximated deduction are presented. The last one is evaluated in practical applications with mixed results.

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Fly Through A Pig's Heart, Thomas Wischgoll Jan 2005

Fly Through A Pig's Heart, Thomas Wischgoll

Computer Science and Engineering Faculty Publications

This exhibit enables you to go on a fantastic voyage through the blood stream. Based on a scan of a real pig’s heart the arterial blood vessels were modeled allowing you to navigate through the vascular system of this heart and explore the blood and its different particles.

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