4,447 research outputs found
Grid service orchestration using the Business Process Execution Language (BPEL)
Modern scientific applications often need to be distributed across grids. Increasingly
applications rely on services, such as job submission, data transfer or data
portal services. We refer to such services as grid services. While the invocation
of grid services could be hard coded in theory, scientific users want to orchestrate
service invocations more flexibly. In enterprise applications, the orchestration of
web services is achieved using emerging orchestration standards, most notably
the Business Process Execution Language (BPEL). We describe our experience
in orchestrating scientific workflows using BPEL. We have gained this experience
during an extensive case study that orchestrates grid services for the automation of
a polymorph prediction application
Unparticle Physics in the Moller Scattering
We investigate the virtual effects of vector unparticles in the Moller
scattering. We derive the analytic expression for scattering amplitudes with
unpolarized beams. We obtain 95% confidence level limits on the unparticle
couplings and with integrated luminosity of
and and 500 GeV energies. We show
that limits on are more sensitive than .Comment: 10 pages, 5 figures, 4 table
Recommended from our members
Evidence for involvement of both IKCa and SKCa channels in hyperpolarizing responses of the rat middle cerebral artery
Endothelium-derived hyperpolarizing factor responses in the rat middle cerebral artery are blocked by inhibiting IKCa channels alone, contrasting with peripheral vessels where block of both IKCa and SKCa is required. As the contribution of IKCa and SKCa to endothelium-dependent hyperpolarization differs in peripheral arteries, depending on the level of arterial constriction, we investigated the possibility that SKCa might contribute to equivalent hyperpolarization in cerebral arteries under certain conditions. METHODS: Rat middle cerebral arteries (approximately 175 microm) were mounted in a wire myograph. The effect of KCa channel blockers on endothelium-dependent responses to the protease-activated receptor 2 agonist, SLIGRL (20 micromol/L), were then assessed as simultaneous changes in tension and membrane potential. These data were correlated with the distribution of arterial KCa channels revealed with immunohistochemistry. RESULTS: SLIGRL hyperpolarized and relaxed cerebral arteries undergoing variable levels of stretch-induced tone. The relaxation was unaffected by specific inhibitors of IKCa (TRAM-34, 1 micromol/L) or SKCa (apamin, 50 nmol/L) alone or in combination. In contrast, the associated smooth-muscle hyperpolarization was inhibited, but only with these blockers in combination. Blocking nitric oxide synthase (NOS) or guanylyl cyclase evoked smooth-muscle depolarization and constriction, with both hyperpolarization and relaxation to SLIGRL being abolished by TRAM-34 alone, whereas apamin had no effect. Immunolabeling showed SKCa and IKCa within the endothelium. CONCLUSIONS: In the absence of NO, IKCa underpins endothelium-dependent hyperpolarization and relaxation in cerebral arteries. However, when NOS is active SKCa contributes to hyperpolarization, whatever the extent of background contraction. These changes may have relevance in vascular disease states where NO release is compromised and when the levels of SKCa expression may be altered
Effects of stoichiometry, purity, etching and distilling on resistance of MgB2 pellets and wire segments
We present a study of the effects of non-stoichiometry, boron purity, wire
diameter and post-synthesis treatment (etching and Mg distilling) on the
temperature dependent resistance and resistivity of sintered MgB2 pellets and
wire segments. Whereas the residual resistivity ratio (RRR) varies between RRR
\~ 4 to RRR > 20 for different boron purity, it is only moderately affected by
non-stoichiometry (from 20% Mg deficiency to 20% Mg excess) and is apparently
independent of wire diameter and presence of Mg metal traces on the wire
surface. The obtained set of data indicates that RRR values in excess of 20 and
residual resistivities as low as rho{0} ~ 0.4 mu Ohm cm are intrinsic material
properties of high purity MgB2
Magnetic flux dynamics in critical state of one-dimensional discrete superconductor
We give a theoretical description of avalanche-like dynamics of magnetic flux
in the critical state of "hard" type-II superconductors using a model of a
one-dimensional multijunction SQUID that well reproduces the main magnetic
properties of these objects. We show that the system under consideration
demonstrates the self-organized criticality. The avalanches of vortices
manifest themselves as jumps of the total magnetic flux in the sample. The
sizes of these jumps have a power-law distribution. Our results are in
qualitative agreement with experiments.Comment: 7 pages, 5 figure
Authentication codes from Δ-ASU hash functions with partially secret keys
An authentication code can be constructed with a family of e-Almost strong universal (e-ASU) hash functions, with the index of hash functions as the authentication key. This paper considers the performance of authentication codes from e-ASU, when the authentication key is only partially secret. We show how to apply the result to privacy amplification against active attacks in the scenario of two independent partially secret strings shared between a sender and a receiver. Keywords: Authentication code; Information theory; Privacy amplification; Unconditional securit
Fast quasi-synchronous harmonic algorithm based on weight window function- mixed radix FFT
According to the requirements of IEC61850-9-2LE, digital energy metering devices mainly adopt 80Ăfr fixed sampling rate. When the harmonic analysis is carried out under asynchronous sampling, it will produce large errors due to spectral leakage. Quasi-Synchronous Algorithm has high accuracy, but the calculation process is complicated and the hardware overheads are high. Based on the characteristics of digital energy metering devices, this paper puts forward a Fast Quasi-Synchronous Harmonic Algorithm using weight window function combined with Mixed Radix Fast Fourier Transform Algorithm. It will reduce the calculation by more than 94%. Compared with the Triangle/Hanning/Nuttall4(III)-Windowed Interpolated FFT Algorithm, the proposed algorithm will perform better in accuracy and has the feature that the more asynchronous of the sampling, the more obvious the error will be
Data Integration by combining big data and survey sample data for finite population inference
The statistical challenges in using big data for making valid statistical
inference in the finite population have been well documented in literature.
These challenges are due primarily to statistical bias arising from
under-coverage in the big data source to represent the population of interest
and measurement errors in the variables available in the data set. By
stratifying the population into a big data stratum and a missing data stratum,
we can estimate the missing data stratum by using a fully responding
probability sample, and hence the population as a whole by using a data
integration estimator. By expressing the data integration estimator as a
regression estimator, we can handle measurement errors in the variables in big
data and also in the probability sample. We also propose a fully nonparametric
classification method for identifying the overlapping units and develop a
bias-corrected data integration estimator under misclassification errors.
Finally, we develop a two-step regression data integration estimator to deal
with measurement errors in the probability sample. An advantage of the approach
advocated in this paper is that we do not have to make unrealistic
missing-at-random assumptions for the methods to work. The proposed method is
applied to the real data example using 2015-16 Australian Agricultural Census
data
Hypersensitive transport in a phase model with multiplicative stimulus
In a simple system with periodic symmetric potential, the phase model under
effect of strong multiplicative noise or periodic square wave, we found a giant
response, in the form of directed flux, to an ultrasmall dc signal. The
resulting flux demonstrates a bell-shaped dependence on multiplicative noise
correlation time and occurs even in the case of large (compared to the signal)
additive noise.Comment: 3 EPS figures, submitted to Phys.Lett.
All-optical switching in metamaterial with high structural symmetry
We argue the possibility of realization of a polarization insensitive
all-optical switching in a planar metamaterial composed of a 4-fold periodic
array of two concentric metal rings placed on a substrate of nonlinear
material. It is demonstrated that a switching may be achieved between
essentially different values of transmission near the resonant frequency of the
high-quality-factor Fano-shape trapped-mode excitation.Comment: 7 pages, 3 figure
- âŠ