1,720,780 research outputs found
An equivalent-effect phenomenon in eddy current non-destructive testing of thin structures
The inductance/impedance due to thin metallic structures in non-destructive
testing (NDT) is difficult to evaluate. In particular, in Finite Element Method
(FEM) eddy current simulation, an extremely fine mesh is required to accurately
simulate skin effects especially at high frequencies, and this could cause an
extremely large total mesh for the whole problem, i.e. including, for example,
other surrounding structures and excitation sources like coils. Consequently,
intensive computation requirements are needed. In this paper, an
equivalent-effect phenomenon is found, which has revealed that alternative
structures can produce the same effect on the sensor response, i.e. mutual
impedance/inductance of coupled coils if a relationship (reciprocal
relationship) between the electrical conductivity and the thickness of the
structure is observed. By using this relationship, the mutual
inductance/impedance can be calculated from the equivalent structures with much
fewer mesh elements, which can significantly save the computation time. In eddy
current NDT, coils inductance/impedance is normally used as a critical
parameter for various industrial applications, such as flaw detection, coating
and microstructure sensing. Theoretical derivation, measurements and
simulations have been presented to verify the feasibility of the proposed
phenomenon
Distinguishing Cause and Effect via Second Order Exponential Models
We propose a method to infer causal structures containing both discrete and
continuous variables. The idea is to select causal hypotheses for which the
conditional density of every variable, given its causes, becomes smooth. We
define a family of smooth densities and conditional densities by second order
exponential models, i.e., by maximizing conditional entropy subject to first
and second statistical moments. If some of the variables take only values in
proper subsets of R^n, these conditionals can induce different families of
joint distributions even for Markov-equivalent graphs.
We consider the case of one binary and one real-valued variable where the
method can distinguish between cause and effect. Using this example, we
describe that sometimes a causal hypothesis must be rejected because
P(effect|cause) and P(cause) share algorithmic information (which is untypical
if they are chosen independently). This way, our method is in the same spirit
as faithfulness-based causal inference because it also rejects non-generic
mutual adjustments among DAG-parameters.Comment: 36 pages, 8 figure
How expository text structure instruction effects reading comprehension
The purpose of this study was to determine the effect of compare/contrast and cause/effect text structure instruction on fifth grade readers’ comprehension of expository text. Three fifth grade students participated in this eight-week study. During the study, the participants met with the researcher thirty minutes a day, five times a week for eight weeks. The focus of the intervention was the compare and contrast and cause and effect text structures. The students learned about the specific text structures by reading leveled passages, identifying target words, and completing a graphic organizer. The results suggested that the participants’ demonstrated growth in expository reading comprehension and knowledge of compare and contrast and cause and effect text structures, but not statistically significantly
SimDialog: A visual game dialog editor
SimDialog is a visual editor for dialog in computer games. This paper
presents the design of SimDialog, illustrating how script writers and
non-programmers can easily create dialog for video games with complex branching
structures and dynamic response characteristics. The system creates dialog as a
directed graph. This allows for play using the dialog with a state-based cause
and effect system that controls selection of non-player character responses and
can provide a basic scoring mechanism for games
The Faraday Quantum Clock and Non-local Photon Pair Correlations
We study the use of the Faraday effect as a quantum clock for measuring
traversal times of evanescent photons through magneto-refractive structures.
The Faraday effect acts both as a phase-shifter and as a filter for circular
polarizations. Only measurements based on the Faraday phase-shift properties
are relevant to the traversal time measurements. The Faraday polarization
filtering may cause the loss of non-local (Einstein-Podolsky-Rosen) two-photon
correlations, but this loss can be avoided without sacrificing the clock
accuracy. We show that a mechanism of destructive interference between
consecutive paths is responsible for superluminal traversal times measured by
the clock.Comment: 6 figure
Helicopter crashworthiness research program
Results are presented from the U.S. Army-Aerostructures Directorate/NASA-Langley Research Center joint research program on helicopter crashworthiness. Through the on-going research program an in-depth understanding was developed on the cause/effect relationships between material and architectural variables and the energy-absorption capability of composite material and structure. Composite materials were found to be efficient energy absorbers. Graphite/epoxy subfloor structures were more efficient energy absorbers than comparable structures fabricated from Kevlar or aluminum. An accurate method predicting the energy-absorption capability of beams was developed
A Map of the Integrated Sachs-Wolfe Signal from Luminous Red Galaxies
We construct a map of the time derivative of the gravitational potential
traced by SDSS Luminous Red Galaxies. The potential decays on large scales due
to cosmic acceleration, leaving an imprint on cosmic microwave background (CMB)
radiation through the integrated Sachs-Wolfe (ISW) effect. With a template fit,
we directly measure this signature on the CMB at a 2-sigma confidence level.
The measurement is consistent with the cross-correlation statistic,
strengthening the claim that dark energy is indeed the cause of the
correlation. This new approach potentially simplifies the cosmological
interpretation. Our constructed linear ISW map shows no evidence for
degree-scale cold and hot spots associated with supervoid and supercluster
structures. This suggests that the linear ISW effect in a concordance
Lambda-CDM cosmology is insufficient to explain the strong CMB imprints from
these structures that we previously reported.Comment: 9 pages, 12 figures, accepted to ApJ. Updated discussion about
redshift cut
Variability of Contact Process in Complex Networks
We study numerically how the structures of distinct networks influence the
epidemic dynamics in contact process. We first find that the variability
difference between homogeneous and heterogeneous networks is very narrow,
although the heterogeneous structures can induce the lighter prevalence.
Contrary to non-community networks, strong community structures can cause the
secondary outbreak of prevalence and two peaks of variability appeared.
Especially in the local community, the extraordinarily large variability in
early stage of the outbreak makes the prediction of epidemic spreading hard.
Importantly, the bridgeness plays a significant role in the predictability,
meaning the further distance of the initial seed to the bridgeness, the less
accurate the predictability is. Also, we investigate the effect of different
disease reaction mechanisms on variability, and find that the different
reaction mechanisms will result in the distinct variabilities at the end of
epidemic spreading.Comment: 6 pages, 4 figure
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