137,409 research outputs found
Accelerating Staggered Fermion Dynamics with the Rational Hybrid Monte Carlo (RHMC) Algorithm
Improved staggered fermion formulations are a popular choice for lattice QCD
calculations. Historically, the algorithm used for such calculations has been
the inexact R algorithm, which has systematic errors that only vanish as the
square of the integration step-size. We describe how the exact Rational Hybrid
Monte Carlo (RHMC) algorithm may be used in this context, and show that for
parameters corresponding to current state-of-the-art computations it leads to a
factor of approximately seven decrease in cost as well as having no step-size
errors.Comment: 4 pages, 2 figures, 1 tabl
Titanium reinforced boron polyimide composite
Program involves development of process technique for boron-polyimide prepeg, lay-up and curing procedures for prepegs when processed under vacuum bag pressure, and development and evaluation of titanium hard points for smooth transition of loads from titanium attach points into boron reinforced body of structure
Technique for predicting the thermal expansion coefficients of cryogenic metallic alloys
Series of measurements on the thermal expansion coefficients of several aerospace alloys and standard materials establish relationships between related alloys that would aid in predicting their thermal expansion reliability. Thermal expansion data are also necessary for the reduction of electrical resistivity measurements of those same materials
The Rational Hybrid Monte Carlo Algorithm
The past few years have seen considerable progress in algorithmic development
for the generation of gauge fields including the effects of dynamical fermions.
The Rational Hybrid Monte Carlo (RHMC) algorithm, where Hybrid Monte Carlo is
performed using a rational approximation in place the usual inverse quark
matrix kernel is one of these developments. This algorithm has been found to be
extremely beneficial in many areas of lattice QCD (chiral fermions, finite
temperature, Wilson fermions etc.). We review the algorithm and some of these
benefits, and we compare against other recent algorithm developements. We
conclude with an update of the Berlin wall plot comparing costs of all popular
fermion formulations.Comment: 15 pages. Proceedings from Lattice 200
The Right to Challenge the Accuracy of Breath Test Results Under Alaska Law
Section 28.90.020 of the Alaska Statutes provides that in prosecutions for drunk driving, if an offense described under this title requires that a chemical test of a person\u27s breath produce a particular result, and the chemical test is administered by a properly calibrated instrument approved by the Department of Public Safety, the result described by statute is not affected by the instrument\u27s working tolerance. This provision appears to prohibit the defense from calling into question the accuracy of a breath test by introducing evidence of uncertainty inherent in the testing procedure. The statute is problematic because due process requires that defendants be permitted to challenge the evidence presented against them. Moreover, there is a strong argument that basing conviction on a single breath sample that is within a known margin of error is a per se violation of due process, as it bases guilt or innocence on a purely fortuitous result. This Article examines the issues with Alaska\u27s statute and proposes using multiple breath tests as a simple, cost-effective solution to this potential abuse of due process
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