10,302 research outputs found
Building ontologies from folksonomies and linked data: Data structures and Algorithms
We present the data structures and algorithms used in the approach for building domain ontologies from folksonomies and linked data. In this approach we extracts domain terms from folksonomies and enrich them with semantic information from the Linked Open Data cloud. As a result, we obtain a domain ontology that combines the emergent knowledge of social tagging systems with formal knowledge from Ontologies
A Pattern Based Approach for Re-engineering Non-Ontological Resources into Ontologies
With the goal of speeding up the ontology development process, ontology engineers are starting to reuse as much as possible available ontologies and non-ontological resources such as classification schemes, thesauri, lexicons and folksonomies, that already have some degree of consensus. The reuse of such non-ontological resources necessarily involves their re-engineering into ontologies. Non-ontological resources are highly heterogeneous in their data model and contents: they encode different types of knowledge, and they can be modeled and implemented in different ways. In this paper we present (1) a typology for non-ontological resources, (2) a pattern based approach for re-engineering non-ontological resources into ontologies, and (3) a use case of the proposed approach
Towards concept identification using a knowledge-intensive approach
This paper presents a method for identifying concepts in microposts and classifying them into a predefined set of categories. The method relies on the DBpedia knowledge base to identify the types of the concepts detected in the messages. For those concepts that are not classified in the ontology we infer their types via the ontology properties which characterise the type
Social tags and linked data for ontology development: a case study in the financial domain
We describe a domain ontology development approach that
extracts domain terms from folksonomies and enrich them
with data and vocabularies from the Linked Open Data
cloud. As a result, we obtain lightweight domain ontologies
that combine the emergent knowledge of social tagging
systems with formal knowledge from Ontologies. In order to
illustrate the feasibility of our approach, we have produced
an ontology in the financial domain from tags available in
Delicious, using DBpedia, OpenCyc and UMBEL as additional
knowledge sources
Synchronization by dynamical relaying in electronic circuit arrays
We experimentally study the synchronization of two chaotic electronic
circuits whose dynamics is relayed by a third parameter-matched circuit, to
which they are coupled bidirectionally in a linear chain configuration. In a
wide range of operating parameters, this setup leads to synchronization between
the outer circuits, while the relaying element remains unsynchronized. The
specifics of the synchronization differ with the coupling level: for low
couplings a state of intermittent synchronization between the outer circuits
coexists with one of antiphase synchronization. Synchronization becomes in
phase for moderate couplings, and for strong coupling identical synchronization
is observed between the outer elements, which are themselves synchronized in a
generalized way with the relaying element. In the latter situation, the middle
element displays a triple scroll attractor that is not possible to obtain when
the chaotic oscillator is isolated.Comment: 7 pages, 12 figure
Enabling folksonomies for knowledge extraction: A semantic grounding approach
Folksonomies emerge as the result of the free tagging activity of a large number of users over a variety of resources. They can be considered as valuable sources from which it is possible to obtain emerging vocabularies that can be leveraged in knowledge extraction tasks. However, when it comes to understanding the meaning of tags in folksonomies, several problems mainly related to the appearance of synonymous and ambiguous tags arise, specifically in the context of multilinguality. The authors aim to turn folksonomies into knowledge structures where tag meanings are identified, and relations between them are asserted. For such purpose, they use DBpedia as a general knowledge base from which they leverage its multilingual capabilities
Vector-tensor gravity from a broken gauge symmetry
In this paper we present a Yang-Mills type gauge theory of vector-tensor
gravity, where the tetrad, the spin connection and vector field are identified
with components of the gauge field. This setup leads to a theory that is
contained in Generalized Proca theories. We solve for static and spherically
symmetric space-time and show that there are two branches of solutions, one
where the metric is asymptotically Schwarzschild even though there is a
cosmological constant in the action, and another one where the metric is
asymptotically (anti-)de Sitter. Also, we study the effect of the vector field
on homogeneous and isotropic spacetimes, finding that it contributes to the
accelerated expansion of the metric
Localized Faraday patterns under heterogeneous parametric excitation
Faraday waves are a classic example of a system in which an extended pattern
emerges under spatially uniform forcing. Motivated by systems in which uniform
excitation is not plausible, we study both experimentally and theoretically the
effect of heterogeneous forcing on Faraday waves. Our experiments show that
vibrations restricted to finite regions lead to the formation of localized
subharmonic wave patterns and change the onset of the instability. The
prototype model used for the theoretical calculations is the parametrically
driven and damped nonlinear Schr\"odinger equation, which is known to describe
well Faraday-instability regimes. For an energy injection with a Gaussian
spatial profile, we show that the evolution of the envelope of the wave pattern
can be reduced to a Weber-equation eigenvalue problem. Our theoretical results
provide very good predictions of our experimental observations provided that
the decay length scale of the Gaussian profile is much larger than the pattern
wavelength.Comment: 10 pages, 9 figures, Accepte
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