10,579 research outputs found
Legal Ontologies for the spanish e-Government
The Electronic Government is a new field of applications for the semantic web where ontologies are becoming an important research technology. The e-Government faces considerable challenges to achieve interoperability given the semantic differences of interpretation, complexity and width of scope. In this paper we present the results obtained in an ongoing project commissioned by the Spanish government that seeks strategies for the e-Government to reduce the problems encountered when delivering services to citizens. We also introduce an e-Government ontology model; within this model a set of legal ontologies are devoted to representing the Real-estate transaction domain used to illustrate this paper
EGO Ontology Model: law and regulation approach for E-Government
The Electronic Government is a new field of applications for the semantic web where ontologies are becoming an important research technology. The e-Government faces considerable challenges to achieve interoperability given the semantic differences of interpretation, complexity and width of scope. In this paper we present the initial state of an e-Government ontology model called EGO. First as a part of a project commissioned by the Spanish government that seeks strategies for the e-Government and second for an ongoing project commissioned by the Mexican government. A set of ontologies (component of EGO), are used to illustrate this paper. Brief applications of this model on an Information Retrieval and on a Semantic Peer-to-Peer within the e-Government context are show
Machine learning techniques to select Be star candidates. An application in the OGLE-IV Gaia south ecliptic pole field
Statistical pattern recognition methods have provided competitive solutions
for variable star classification at a relatively low computational cost. In
order to perform supervised classification, a set of features is proposed and
used to train an automatic classification system. Quantities related to the
magnitude density of the light curves and their Fourier coefficients have been
chosen as features in previous studies. However, some of these features are not
robust to the presence of outliers and the calculation of Fourier coefficients
is computationally expensive for large data sets. We propose and evaluate the
performance of a new robust set of features using supervised classifiers in
order to look for new Be star candidates in the OGLE-IV Gaia south ecliptic
pole field. We calculated the proposed set of features on six types of variable
stars and on a set of Be star candidates reported in the literature. We
evaluated the performance of these features using classification trees and
random forests along with K-nearest neighbours, support vector machines, and
gradient boosted trees methods. We tuned the classifiers with a 10-fold
cross-validation and grid search. We validated the performance of the best
classifier on a set of OGLE-IV light curves and applied this to find new Be
star candidates. The random forest classifier outperformed the others. By using
the random forest classifier and colour criteria we found 50 Be star candidates
in the direction of the Gaia south ecliptic pole field, four of which have
infrared colours consistent with Herbig Ae/Be stars. Supervised methods are
very useful in order to obtain preliminary samples of variable stars extracted
from large databases. As usual, the stars classified as Be stars candidates
must be checked for the colours and spectroscopic characteristics expected for
them
On the Hierarchical Preconditioning of the PMCHWT Integral Equation on Simply and Multiply Connected Geometries
We present a hierarchical basis preconditioning strategy for the
Poggio-Miller-Chang-Harrington-Wu-Tsai (PMCHWT) integral equation considering
both simply and multiply connected geometries.To this end, we first consider
the direct application of hierarchical basis preconditioners, developed for the
Electric Field Integral Equation (EFIE), to the PMCHWT. It is notably found
that, whereas for the EFIE a diagonal preconditioner can be used for obtaining
the hierarchical basis scaling factors, this strategy is catastrophic in the
case of the PMCHWT since it leads to a severly ill-conditioned PMCHWT system in
the case of multiply connected geometries. We then proceed to a theoretical
analysis of the effect of hierarchical bases on the PMCHWT operator for which
we obtain the correct scaling factors and a provably effective preconditioner
for both low frequencies and mesh refinements. Numerical results will
corroborate the theory and show the effectiveness of our approach
Distances and Kinematics of Gould Belt Star-Forming Regions with Gaia DR2 results
We present an analysis of the astrometric results from Gaia second data
release (DR2) to Young Stellar Objects (YSOs) in star-forming regions related
to the Gould Belt. These regions are Barnard 59, Lupus 1 to 4, Chamaeleon I and
II, -Chamaeleontis, the Cepheus flare, IC 5146 and Corona Australis.
The mean distance to the YSOs in each region are consistent with earlier
estimations, though a significant improvement to the final errors was obtained.
The mean distances to the star-forming regions were used to fit an ellipsoid of
size pc, and centered at
pc, consistent with recently
determined parameter of the Gould Belt. The mean proper motions were combined
with radial velocities from the literature to obtain the three dimensional
motion of the star-forming regions, which are consistent with a general
expansion of the Gould Belt. We estimate that this expansion is occurring at a
velocity of km s. This is the first time that YSOs motions
are used to investigate the kinematic of the Gould Belt. As an interesting side
result, we also identified stars with large peculiar velocities.Comment: 18 pages, 14 figures, and 5 tables. Accepted for publication in The
Astrophysical Journa
Light Scattering from Nonequilibrium Concentration Fluctuations in a Polymer solution
We have performed light-scattering measurements in dilute and semidilute
polymer solutions of polystyrene in toluene when subjected to stationary
temperature gradients. Five solutions with concentrations below and one
solution with a concentration above the overlap concentration were
investigated. The experiments confirm the presence of long-range nonequilibrium
concentration fluctuations which are proportional to , where
is the applied temperature gradient and is the wave number of
the fluctuations. In addition, we demonstrate that the strength of the
nonequilibrium concentration fluctuations, observed in the dilute and
semidilute solution regime, agrees with theoretical values calculated from
fluctuating hydrodynamics. Further theoretical and experimental work will be
needed to understand nonequilibrium fluctuations in polymer solutions at higher
concentrations.Comment: revtex, 16 pages, 7 figures. J. Chem. Phys., to appea
EgoIR: ontology-based information retrieval intended for eGovernment
The eGovernment is a field of applications for the Semantic Web. The
eGovernment also is becoming an important research area and faces considerable
challenges to achieve interoperability because of the semantic differences of
interpretation, complexity and width of scope. It is however an open question how
to apply these techniques fruitfully in the eGovernment domain. This paper addresses
the importance of providing a semantic application that, within the eGovernment
domain, is capable of dealing with the issue of the retrieval of government
documentation in a timely and accurate way. In this paper, we present an approach
ontology-based for retrieving government information
Semantic based P2P System for local e-Government
The Electronic Government is an emerging field of applications for the Semantic Web where ontologies are becoming an important research technology. The e-Government faces considerable challenges to achieve interoperability given the semantic differences of interpretation, omplexity and width of scope. This paper addresses the importance of providing an infrastructure capable of dealing with issues such as: communications between public administrations across government and retrieval of official and non official documents in a timely, secure and accurate way at the back office. A semantic peer-to-peer approach is proposed to enhance the information management at the e-Government domain; this approach is integrated with a Government Information Retrieval system and it reuses the EGO Model which can be deployed within the e-Government context
Classical analogy for the deflection of flux avalanches by a metallic layer
Sudden avalanches of magnetic flux bursting into a superconducting sample
undergo deflections of their trajectories when encountering a conductive layer
deposited on top of the superconductor. Remarkably, in some cases flux is
totally excluded from the area covered by the conductive layer. We present a
simple classical model that accounts for this behaviour and considers a
magnetic monopole approaching a semi-infinite conductive plane. This model
suggests that magnetic braking is an important mechanism responsible for
avalanche deflection.Comment: 14 pages, 5 figure
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