Papers by Fernando Bobillo
Finite Fuzzy Description Logics: A Crisp Representation for Finite Fuzzy ALCH
Classical ontologies are not suitable to represent imprecise nor uncertain pieces of information.... more Classical ontologies are not suitable to represent imprecise nor uncertain pieces of information. Fuzzy Description Logics were born to represent the former type of knowledge, but they require an appropriate fuzzy language to be agreed and an important number of available resources to be adapted. This paper faces these problems by presenting a reasoning preserving procedure to obtain a crisp representation for a fuzzy extension of the logic SROIQ which uses Gödel implication in the semantics of fuzzy concept and role subsumption. This reduction allows to reuse a crisp representation language as well as currently available reasoners. Our procedure is optimized with respect to the related work, reducing the size of the resulting knowledge base, and is implemented in DeLorean, the first reasoner supporting fuzzy OWL DL.
Finite Fuzzy Description Logics: A Crisp Representation for Finite Fuzzy $mathcalALCH$
Iswc, 2007
Classical ontologies are not suitable to represent imprecise nor uncertain pieces of information.... more Classical ontologies are not suitable to represent imprecise nor uncertain pieces of information. As a solution we will combine fuzzy Description Logics with a possibilistic layer. Then, we will show how to perform reasoning by relying on classical existing reasoners.
The massive spread of mobile computing in our daily lives has attracted a huge community of mobil... more The massive spread of mobile computing in our daily lives has attracted a huge community of mobile apps developers. These developers can take advantage of the benefits of semantic technologies (such as knowledge sharing and reusing, knowledge decoupling, etc.) to enhance their applications. Moreover, the use of semantic reasoners would enable them to create more intelligent applications capable of inferring logical consequences from the knowledge considered. However, using semantic APIs and reasoners on current Android-based devices is not problem-free and, currently, there are no remarkable efforts to enable mobile devices with semantic reasoning capabilities.
Fuzzy Sets and Systems, Jun 1, 2011
Fuzzy Description Logics (DLs) are a family of logics which allow the representation of (and the ... more Fuzzy Description Logics (DLs) are a family of logics which allow the representation of (and the reasoning with) structured knowledge affected by vagueness. Although most of the not very expressive crisp DLs, such as ALC, enjoy the Finite Model Property (FMP), this is not the case once we move into the fuzzy case. In this paper we show that if we allow arbitrary knowledge bases, then the fuzzy DLs ALC under Lukasiewicz and Product fuzzy logics do not verify the FMP even if we restrict to witnessed models; in other words, finite satisfiability and witnessed satisfiability are different for arbitrary knowledge bases. The aim of this paper is to point out the failure of FMP because it affects several algorithms published in the literature for reasoning under fuzzy ALC.
Iswc, 2008
Classical ontologies are not suitable to represent imprecise or vague pieces of information, whic... more Classical ontologies are not suitable to represent imprecise or vague pieces of information, which has led to fuzzy extensions of Description Logics. In order to support an early acceptance of the OWL 1.1 ontology language, we present DeLorean, the first reasoner that supports a fuzzy extension of the Description Logic SROIQ, closely equivalent to it. It implements some interesting optimization techniques, whose usefulness is shown in a preliminary empirical evaluation.
Iswc, 2007
Classical ontologies are not suitable to represent imprecise nor uncertain pieces of information.... more Classical ontologies are not suitable to represent imprecise nor uncertain pieces of information. Fuzzy Description Logics were born to represent the former type of knowledge, but they require an appropriate fuzzy language to be agreed and an important number of available resources to be adapted. This paper faces these problems by presenting a reasoning preserving procedure to obtain a crisp representation for a fuzzy extension of the logic SROIQ which uses Gödel implication in the semantics of fuzzy concept and role subsumption. This reduction allows to reuse a crisp representation language as well as currently available reasoners. Our procedure is optimized with respect to the related work, reducing the size of the resulting knowledge base, and is implemented in DeLorean, the first reasoner supporting fuzzy OWL DL.
Fuzzy description logics under G�del semantics
Ijar, 2009
Classical ontologies are not suitable to represent vague pieces of information, which has lead to... more Classical ontologies are not suitable to represent vague pieces of information, which has lead to the birth of Fuzzy Description Logics as an appropriate formalism to represent this type of knowledge. Different families of fuzzy operators lead to Fuzzy Description Logics with different properties. This paper studies Fuzzy Description Logics under a semantics given by the Gödel family of fuzzy
Fuzzy Description Logics have been proposed as a family of languages to describe vague or impreci... more Fuzzy Description Logics have been proposed as a family of languages to describe vague or imprecise structured knowledge. This work deals with one of the less studied constructors, qualified cardinality restrictions, showing some counter-intuitive behaviours under Łukasiewicz semantics, and proposing a new semantics and the corresponding reasoning algorithm.
International Journal of Approximate Reasoning, Mar 1, 2009
Classical ontologies are not suitable to represent vague pieces of information, which has lead to... more Classical ontologies are not suitable to represent vague pieces of information, which has lead to the birth of Fuzzy Description Logics as an appropriate formalism to represent this type of knowledge. Different families of fuzzy operators lead to Fuzzy Description Logics with different properties. This paper studies Fuzzy Description Logics under a semantics given by the Gödel family of fuzzy operators. We investigate some logical properties and show the decidability of a fuzzy extension of the logic SROIQ, theoretical basis of the language OWL 1.1, by providing a reasoning preserving procedure to obtain a crisp representation for it. Additionally, we show how to represent some types of concept and role modifiers.
Tractability of the Crisp Representations of Tractable Fuzzy Description Logics
Reasoning with the finitely many-valued Lukasiewicz fuzzy Description Logic SROIQ
Isci, 2011
Fuzzy Description Logics are a formalism for the representation of structured knowledge affected ... more Fuzzy Description Logics are a formalism for the representation of structured knowledge affected by imprecision or vagueness. They have become popular as a language for fuzzy ontology representation. To date, most of the work in this direction has focused on the so-called Zadeh family of fuzzy operators (or fuzzy logic), which has several limitations. In this paper, we generalize existing
Applications for mobile devices could often show a more intelligent behavior by using a semantic ... more Applications for mobile devices could often show a more intelligent behavior by using a semantic reasoner to discover new knowledge. Unfortunately, using Description Logic reasoners on Android devices is not trivial. In this paper we continue our previous work on investigating the use of semantic reasoners on mobile devices. In particular, we port some new OWL 2 EL reasoners to Android and analyze the results of some experiments measuring the performance of several OWL 2 DL and OWL 2 EL reasoners on Android smartphones and tablets.
Information overload is a common problem in current Information and Knowledge Based Systems. The ... more Information overload is a common problem in current Information and Knowledge Based Systems. The Web, being the largest public available information source, is particularly affected by this issue, so several approaches to deal with it are being developed by Semantic Web researchers. Most of them are based on using context knowledge to delimit which information is significant to a user, such as the CDR ontology design pattern, our previous contribution to handle relevance depending on context in OWL ontologies. In this work, we extend this proposal with fuzzy Description Logics formalisms in order to represent vague knowledge about context and application-specific facts, and to manage the degree of importance of a relevance relation. A main advantage of our proposal is that current (non-fuzzy) standards and inference engines can be used.
Semantic reasoning on mobile devices: Do Androids dream of efficient reasoners?
Web Semantics: Science, Services and Agents on the World Wide Web, 2015
The massive spread of mobile computing in our daily lives has attracted a huge community of mobil... more The massive spread of mobile computing in our daily lives has attracted a huge community of mobile application (apps) developers. These developers can take advantage of the benefits of semantic technologies (such as knowledge sharing and reusing, and knowledge decoupling) to enhance their applications. Moreover, the use of semantic reasoners would enable them to create more intelligent applications capable of discovering new knowledge, inferred from the available information. However, using semantic APIs and reasoners on current mobile devices is not a trivial task. In this paper, we show that the most popular current available Description Logics (DL) reasoners can be used on Android-based devices, and detail the efforts needed to port them to the Android platform. We also analyze the performance of these reasoners on current smartphones/tablets against more than 300 ontologies from the ORE 2013 ontology set, showing that, despite a notable difference with respect to desktop computers, their use is feasible.
Fuzzy Description Logics (fuzzy DLs) have been proposed as a language to describe structured know... more Fuzzy Description Logics (fuzzy DLs) have been proposed as a language to describe structured knowledge with vague concepts. In [23], a solution based on Mixed Integer Linear Programming has been proposed to deal with fuzzy DLs under Łukasiewicz semantics in which typical membership functions, such as triangular and trapezoidal functions, can be explicitly represented in the language.
Ontologías Difusas [In Spanish]
Managing vagueness in ontologies
ABSTRACT
Fuzzy Description Logics are a family of logics which allow to deal with structured knowledge aff... more Fuzzy Description Logics are a family of logics which allow to deal with structured knowledge affected by vagueness. Although a relatively important amount of work has been carried out in the last years, current fuzzy DLs are open to be extend with several features worked out in the fuzzy logic literature. In this work, we extend fuzzy DLs with fuzzy truth values, allowing to state sentences such as "Tina is young is almost true".
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Papers by Fernando Bobillo