3,482 research outputs found
Processing SPARQL queries with regular expressions in RDF databases
Background: As the Resource Description Framework (RDF) data model is widely used for modeling and sharing a lot of online bioinformatics resources such as Uniprot (dev.isb-sib.ch/projects/uniprot-rdf) or Bio2RDF (bio2rdf.org), SPARQL - a W3C recommendation query for RDF databases - has become an important query language for querying the bioinformatics knowledge bases. Moreover, due to the diversity of users' requests for extracting information from the RDF data as well as the lack of users' knowledge about the exact value of each fact in the RDF databases, it is desirable to use the SPARQL query with regular expression patterns for querying the RDF data. To the best of our knowledge, there is currently no work that efficiently supports regular expression processing in SPARQL over RDF databases. Most of the existing techniques for processing regular expressions are designed for querying a text corpus, or only for supporting the matching over the paths in an RDF graph.
Results: In this paper, we propose a novel framework for supporting regular expression processing in SPARQL query. Our contributions can be summarized as follows. 1) We propose an efficient framework for processing SPARQL queries with regular expression patterns in RDF databases. 2) We propose a cost model in order to adapt the proposed framework in the existing query optimizers. 3) We build a prototype for the proposed framework in C++ and conduct extensive experiments demonstrating the efficiency and effectiveness of our technique.
Conclusions: Experiments with a full-blown RDF engine show that our framework outperforms the existing ones by up to two orders of magnitude in processing SPARQL queries with regular expression patterns.X113sciescopu
Correlation function of dyonic strings
We investigate the two- and three-point correlation functions of the dyonic
magnon and spike, which correspond to the solitonic string moving in the
Poincare AdS and three-dimensional sphere. We show that the coupling between
two dyonic magnons or spikes together with a marginal scalar operator in the
string theory is exactly the same as one obtained by the RG analysis in the
gauge theory.Comment: 15 pages, no figur
Rotating Black Hole Thermodynamics with a Particle Probe
The thermodynamics of Myers-Perry black holes in general dimensions are
studied using a particle probe. When undergoing particle absorption, the
changes of the entropy and irreducible mass are shown to be dependent on the
particle radial momentum. The black hole thermodynamic behaviors are dependent
on dimensionality for specific rotations. For a 4-dimensional Kerr black hole,
its black hole properties are maintained for any particle absorption.
5-dimensional black holes can avoid a naked ring singularity by absorbing a
particle in specific momenta ranges. Black holes over 6 dimensions become
ultra-spinning black holes through a specific form of particle absorption. The
microscopical changes are interpreted in limited cases of Myers-Perry black
holes using Kerr/CFT correspondence. We systematically describe the black hole
properties changed by particle absorption in all dimensions.Comment: 14 page
Scale growth of structures in the turbulent boundary layer with a rod-roughened wall
Direct numerical simulation of a turbulent boundary layer over a rod-roughened wall is performed with a long streamwise domain to examine the streamwise-scale growth mechanism of streamwise velocity fluctuating structures in the presence of two-dimensional (2-D) surface roughness. An instantaneous analysis shows that there is a slightly larger population of long structures with a small helix angle (spanwise inclinations relative to streamwise) and a large spanwise width over the rough-wall compared to that over a smooth-wall. Further inspection of time-evolving instantaneous fields clearly exhibits that adjacent long structures combine to form a longer structure through a spanwise merging process over the rough-wall; moreover, spanwise merging for streamwise scale growth is expected to occur frequently over the rough-wall due to the large spanwise scales generated by the 2-D roughness. Finally, we examine the influence of a large width and a small helix angle of the structures over the rough-wall with regard to spatial two-point correlation. The results show that these factors can increase the streamwise coherence of the structures in a statistical sense.open
Modified Aperture Coupling Annular-Ring Antenna fed by Stripline
Various types of feed structures for microstrip antennas are compared. Broad bandwidth is obtained using aperture coupling with impedance matching. One of advantages in aperture coupling is polarization purity. A modified aperture coupling annular-ring antenna fed by microstrip is presented in this paper. This antenna structure can be considered as the combination of aperture feeding and proximity feeding an annular-ring antenna. It has both advantages in the polarization purity and in reduction of back radiation. From the structure based on the proximity feed annular-ring antenna, an aperture layer is inserted and modified as well as an aperture size to enhance bandwidth
Multi-band Internal Loop Antenna with Inserted Concentric Rings for Mobile Terminals
Loop Antenna with inserted concentric rings is proposed for mobile terminals. Inserting concentric ring(s) on the loop element improves the impedance bandwidth of the proposed antenna. Measurement results show that the bandwidth includes GSM, DCS, PCS, and UMTS bands
Application of Artificial Neural Network to Search for Gravitational-Wave Signals Associated with Short Gamma-Ray Bursts
We apply a machine learning algorithm, the artificial neural network, to the
search for gravitational-wave signals associated with short gamma-ray bursts.
The multi-dimensional samples consisting of data corresponding to the
statistical and physical quantities from the coherent search pipeline are fed
into the artificial neural network to distinguish simulated gravitational-wave
signals from background noise artifacts. Our result shows that the data
classification efficiency at a fixed false alarm probability is improved by the
artificial neural network in comparison to the conventional detection
statistic. Therefore, this algorithm increases the distance at which a
gravitational-wave signal could be observed in coincidence with a gamma-ray
burst. In order to demonstrate the performance, we also evaluate a few seconds
of gravitational-wave data segment using the trained networks and obtain the
false alarm probability. We suggest that the artificial neural network can be a
complementary method to the conventional detection statistic for identifying
gravitational-wave signals related to the short gamma-ray bursts.Comment: 30 pages, 10 figure
Oxygen-Vacancy-Induced Orbital Reconstruction of Ti Ions at the Interface of LaAlO3/SrTiO3 Heterostructures: A Resonant Soft-X-Ray Scattering Study
Resonant soft-x-ray scattering measurements have been performed to investigate interface electronic structures of (LaAlO3/SrTiO3) superlattices. Resonant scattering intensities at superlattice reflections show clear evidence of degeneracy lifting in t(2g) states of interface Ti ions. Polarization dependence of intensities indicates the energy of d(xy) states is lower by similar to 1 eV than two other t(2g) states. The energy splitting is insensitive to epitaxial strain. The orbital reconstruction is induced by oxygen vacancies and confined to the interface within two unit cells, indicating charge compensation at the polar interfaces. DOI: 10.1103/PhysRevLett.110.017401X112723Nsciescopu
Mass inflation in f(R) gravity: A conjecture on the resolution of the mass inflation singularity
We study gravitational collapse of a charged black hole in f(R) gravity using
double-null formalism. We require cosmological stability to f(R) models; we
used the Starobinsky model and the R + (1/2)cR^2 model. Charged black holes in
f(R) gravity can have a new type of singularity due to higher curvature
corrections, the so-called f(R)-induced singularity, although it is highly
model-dependent. As the advanced time increases, the internal structure will
approach the Cauchy horizon, which may not be an inner apparent horizon. There
is mass inflation as one approaches the Cauchy horizon and hence the Cauchy
horizon may be a curvature singularity with nonzero area. However, the Ricci
scalar is finite for an out-going null observer. This can be integrated as
follows: Cosmologically stable higher curvature corrections of the Ricci scalar
made it bounded even in the presence of mass inflation. Finally, we conjecture
that if there is a general action including general higher curvature
corrections with cosmological stability, then the corrections can make all
curvature components finite even in the presence of mass inflation. This might
help us to resolve the problem of inner horizon instability of regular black
hole models.Comment: 31 pages, 15 figure
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