922,591 research outputs found
Consistency check of {\Lambda}CDM phenomenology
The standard model of cosmology LCDM assumes general relativity, flat space,
and the presence of a positive cosmological constant. We relax these
assumptions allowing spatial curvature, time-dependent effective dark energy
equation of state, as well as modifications of the Poisson equation for the
lensing potential, and modifications of the growth of linear matter density
perturbations in alternate combinations. Using six parameters characterizing
these relations, we check LCDM for consistency utilizing cosmic microwave
background anisotropies, cross correlations thereof with high-redshift galaxies
through the integrated Sachs-Wolfe effect, the Hubble constant, supernovae and
baryon acoustic oscillation distances, as well as the relation between weak
gravitational lensing and galaxy flows. In all scenarios, we find consistency
of the concordance model at the 95% confidence level. However, we emphasize
that constraining supplementary background parameters and parametrizations of
the growth of large-scale structure separately may lead to a priori exclusion
of viable departures from the concordance model.Comment: 15 pages, 14 figures, 4 tables; revision with minor change
Current Status Of Velocity Field Surveys: A Consistency Check
We present an analysis comparing the bulk--flow measurements for six recent
peculiar velocity surveys, namely, ENEAR, SFI, RFGC, SBF and the Mark III
singles and group catalogs. We study whether the direction of the bulk--flow
estimates are consistent with each other and construct the full three
dimensional bulk--flow vectors for each survey. We show that although the
surveys differ in their geometry, galaxy morphologies, distance measures and
measurement errors, their bulk flow vectors are expected to be highly
correlated and in fact show impressive agreement in all cases. We found a
combined weighted mean bulk motion of 330 km s km s
toward and
in a sphere with an effective depth of km s.Comment: 16 pages, 2 figures 2 tables, minor changes, reflects published
versio
'Constraint consistency' at all orders in Cosmological perturbation theory
We study the equivalence of two - order-by-order Einstein's equation and
Reduced action - approaches to cosmological perturbation theory at all orders
for different models of inflation. We point out a crucial consistency check
which we refer to as 'Constraint consistency' that needs to be satisfied. We
propose a quick and efficient method to check the consistency for any model
including modified gravity models. Our analysis points out an important feature
which is crucial for inflationary model building i.e., all `constraint'
inconsistent models have higher order Ostrogradsky's instabilities but the
reverse is not true. In other words, one can have models with constraint lapse
function and shift vector, though it may have Ostrogradsky's instabilities. We
also obtain the single variable equation for non-canonical scalar field in the
limit of power-law inflation for the second-order perturbed variables.Comment: 25 page
Building validation tools for knowledge-based systems
The Expert Systems Validation Associate (EVA), a validation system under development at the Lockheed Artificial Intelligence Center for more than a year, provides a wide range of validation tools to check the correctness, consistency and completeness of a knowledge-based system. A declarative meta-language (higher-order language), is used to create a generic version of EVA to validate applications written in arbitrary expert system shells. The architecture and functionality of EVA are presented. The functionality includes Structure Check, Logic Check, Extended Structure Check (using semantic information), Extended Logic Check, Semantic Check, Omission Check, Rule Refinement, Control Check, Test Case Generation, Error Localization, and Behavior Verification
Brane World Sum Rules
A set of consistency conditions is derived from Einstein equations for brane
world scenarios with a spatially periodic internal space. In particular, the
sum of the total tension of the flat branes and the non-negative integral of
the gradient energy of the bulk scalars must vanish. This constraint allows us
to make a simple consistency check of several models. We show that the
two-brane Randall-Sundrum model satisfies this constraint, but it does not
allow a generalization with smooth branes (domain walls), independently of the
issue of supersymmetry. The Goldberger-Wise model of brane stabilization has to
include the backreaction on the metric and the fine tuning of the cosmological
constant to satisfy the constraints. We check that this is achieved in the
DeWolfe-Freedman-Gubser-Karch scenario. Our constraints are automatically
satisfied in supersymmetric brane world models.Comment: 13 pages, JHEP, references adde
A Benchmark Estimate for the Capital Stock. An Optimal Consistency Method
There are alternative methods to estimate a capital stock for a benchmark year. These methods, however, do not allow for an independent check, which could establish whether the estimated benchmark level is too high or too low. I propose here an optimal consistency method (OCM), which may allow estimating a capital stock level for a benchmark year and/or checking the consistency of alternative estimates of a benchmark capital stock.Benchmark capital, Perpetual inventory method (PIM), Optimal consistency method (OCM)
Metamodel-based model conformance and multiview consistency checking
Model-driven development, using languages such as UML and BON, often makes use of multiple diagrams (e.g., class and sequence diagrams) when modeling systems. These diagrams, presenting different views of a system of interest, may be inconsistent. A metamodel provides a unifying framework in which to ensure and check consistency, while at the same time providing the means to distinguish between valid and invalid models, that is, conformance. Two formal specifications of the metamodel for an object-oriented modeling language are presented, and it is shown how to use these specifications for model conformance and multiview consistency checking. Comparisons are made in terms of completeness and the level of automation each provide for checking multiview consistency and model conformance. The lessons learned from applying formal techniques to the problems of metamodeling, model conformance, and multiview consistency checking are summarized
On the Vacuum Structure of the 3-2 Model
The 3-2 model of dynamical supersymmetry breaking is revisited, with some
incidentally new observations on the vacuum structure. Extra matter is then
added, and the vacuum structure is further studied. The parametric dependence
of the location of the vacuum provides a consistency check of Seiberg duality.Comment: 9 pages, 1 figur
Consistency of shared reference frames should be reexamined
In a recent Letter [G. Chiribella et al., Phys. Rev. Lett. 98, 120501
(2007)], four protocols were proposed to secretly transmit a reference frame.
Here We point out that in these protocols an eavesdropper can change the
transmitted reference frame without being detected, which means the consistency
of the shared reference frames should be reexamined. The way to check the above
consistency is discussed. It is shown that this problem is quite different from
that in previous protocols of quantum cryptography.Comment: 3 pages, 1 figure, comments are welcom
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