21,485 research outputs found
PowerAqua: fishing the semantic web
The Semantic Web (SW) offers an opportunity to develop novel, sophisticated forms of question answering (QA). Specifically, the availability of distributed semantic markup on a large scale opens the way to QA systems which can make use of such semantic information to provide precise, formally derived answers to questions. At the same time the distributed, heterogeneous, large-scale nature of the semantic information introduces significant challenges. In this paper we describe the design of a QA system, PowerAqua, designed to exploit semantic markup on the web to provide answers to questions posed in natural language. PowerAqua does not assume that the user has any prior information about the semantic resources. The system takes as input a natural language query, translates it into a set of logical queries, which are then answered by consulting and aggregating information derived from multiple heterogeneous semantic sources
A computational scheme to evaluate Hamaker constants of molecules with practical size and anisotropy
We propose a computational scheme to evaluate Hamaker constants, , of
molecules with practical sizes and anisotropies. Upon the increasing
feasibility of diffusion Monte Carlo (DMC) methods to evaluate binding curves
for such molecules to extract the constants, we discussed how to treat the
averaging over anisotropy and how to correct the bias due to the
non-additivity. We have developed a computational procedure for dealing with
the anisotropy and reducing statistical errors and biases in DMC valuations,
based on possible validations on predicted . We applied the scheme to
cyclohexasilane molecule, SiH, used in 'printed electronics'
fabrications, getting [zJ], being in plausible range
supported even by other possible extrapolations. The scheme provided here would
open a way to use handy {\it ab initio} evaluations to predict wettabilities as
in the form of materials informatics over broader molecules.Comment: The manuscript was revised according to review comment
Algebras for parameterised monads
Parameterised monads have the same relationship to adjunctions with parameters as monads do to adjunctions. In this paper, we investigate algebras for parameterised monads. We identify the Eilenberg-Moore category of algebras for parameterised monads and prove a generalisation of Beck’s theorem characterising this category. We demonstrate an application of this theory to the semantics of type and effect systems
Outlaw Community Innovations
Recent studies of outlaw communities provide qualitative evidence of their existence and the organisation of the underlying innovation processes. We provide descriptive results from a large scale survey of two online outlaw communities focussing on Microsoft's XBox. In line with previous findings, we identify two types of participants in outlaw communities - user innovators and adopters. Based on 2,256 responses, we find that users modify their XBox mainly to be able to increase the set of available functions of their XBox. Users are also motivated to modify their XBox for the sake of having fun and to conduct pirate behaviour. Finally, the results from our survey suggest that user innovators are largely intrinsically motivated by fun and the intellectual stimulation of writing code for homebrew software
Volatility clustering and scaling for financial time series due to attractor bubbling
A microscopic model of financial markets is considered, consisting of many
interacting agents (spins) with global coupling and discrete-time thermal bath
dynamics, similar to random Ising systems. The interactions between agents
change randomly in time. In the thermodynamic limit the obtained time series of
price returns show chaotic bursts resulting from the emergence of attractor
bubbling or on-off intermittency, resembling the empirical financial time
series with volatility clustering. For a proper choice of the model parameters
the probability distributions of returns exhibit power-law tails with scaling
exponents close to the empirical ones.Comment: For related publications see http://www.helbing.or
Constraining the expansion history of the universe from the red shift evolution of cosmic shear
We present a quantitative analysis of the constraints on the total equation
of state parameter that can be obtained from measuring the red shift evolution
of the cosmic shear. We compare the constraints that can be obtained from
measurements of the spin two angular multipole moments of the cosmic shear to
those resulting from the two dimensional and three dimensional power spectra of
the cosmic shear. We find that if the multipole moments of the cosmic shear are
measured accurately enough for a few red shifts the constraints on the dark
energy equation of state parameter improve significantly compared to those that
can be obtained from other measurements.Comment: 17 pages, 4 figure
Pressure-temperature Phase Diagram of Polycrystalline UCoGe Studied by Resistivity Measurement
Recently, coexistence of ferromagnetism (T_Curie = 2.8K) and
superconductivity (T_sc = 0.8K) has been reported in UCoGe, a compound close to
a ferromagnetic instability at ambient pressure P. Here we present resistivity
measurements under pressure on a UCoGe polycrystal. The phase diagram obtained
from resistivity measurements on a polycrystalline sample is found to be
qualitatively different to those of all other ferromagnetic superconductors. By
applying high pressure, ferromagnetism is suppressed at a rate of 1.4 K/GPa. No
indication of ferromagnetic order has been observed above P ~ 1GPa. The
resistive superconducting transition is, however, quite stable in temperature
and persists up to the highest measured pressure of about 2.4GPa.
Superconductivity would therefore appear also in the paramagnetic phase.
However, the appearance of superconductivity seems to change at a
characteristic pressure P* ~ 0.8GPa. Close to a ferromagnetic instability, the
homogeneity of the sample can influence strongly the electronic and magnetic
properties and therefore bulk phase transitions may differ from the
determination by resistivity measurements.Comment: 4 pages, 4 figures, submitted to J. Phys. Soc. Jp
Local Ferroelectricity in SrTiO_3 Thin Films
The temperature-dependent polarization of SrTiO_3 thin films is investigated
using confocal scanning optical microscopy. A homogeneous out-of-plane and
inhomogeneous in-plane ferroelectric phase are identified from images of the
linear electrooptic response. Both hysteretic and non-hysteretic behavior are
observed under a dc bias field. Unlike classical transitions in bulk
ferroelectrics, local ferroelectricity is observed at temperatures far above
the dielectric permittivity maximum. The results demonstrate the utility of
local probe experiments in understanding inhomogeneous ferroelectrics.Comment: 8 pages, 3 figures, accepted for publication in PR
fNIRS neuroimaging in olfactory research: A systematic literature review
There are a number of key features which make olfaction difficult to study; subjective processes of odor detection, discrimination and identification, and individualistic odor hedonic perception and associated odor memories. In this systematic review we explore the role functional near-infrared spectroscopy (fNIRS) has played in understanding olfactory perception in humans. fNIRS is an optical neuroimaging technique able to measure changes in brain hemodynamics and oxygenation related to neural electrical activity. Adhering to PRISMA guidelines, results of this search found that generally the majority of studies involving healthy adult subjects observed increased activity in response to odors. Other population types were also observed, such as infants, individuals with autism, attention deficit hyperactivity disorder (ADHD), post-traumatic stress disorder (PTSD), mild cognitive impairment (MCI) and dysosmia. fNIRS coverage heavily favored the prefrontal cortex, temporal and parietal regions. This review finds that odor induced cortical activation is dependent on multiple factors, such as odorant type, gender and population type. This review also finds that there is room for improvement in areas such as participant diversity, use of wearable fNIRS systems, physiological monitoring and multi-distance channels
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