2,999,540 research outputs found
A different view on the vector-valued empirical mode decomposition (VEMD)
The empirical mode decomposition (EMD) has achieved its reputation by
providing a multi-scale time-frequency representation of nonlinear and/or
nonstationary signals. To extend this method to vector-valued signals (VvS) in
multidimensional (multi-D) space, a multivariate EMD (MEMD) has been designed
recently, which employs an ensemble projection to extract local extremum
locations (LELs) of the given VvS with respect to different projection
directions. This idea successfully overcomes the problems of locally defining
extrema of VvS. Different from the MEMD, where vector-valued envelopes (VvEs)
are interpolated based on LELs extracted from the 1-D projected signal, the
vector-valued EMD (VEMD) proposed in this paper employs a novel back projection
method to interpolate the VvEs from 1-D envelopes in the projected space.
Considering typical 4-D coordinates (3-D location and time), we show by
numerical simulations that the VEMD outperforms state-of-art methods.Comment: 7th International Congress on Image and Signal Processing (CISP
Quantum simulation of Dirac fermion mode, Majorana fermion mode and Majorana-Weyl fermion mode in cavity QED lattice
Quantum simulation aims to simulate a quantum system using a controble
laboratory system that underline the same mathematical model. Cavity QED
lattice system is that prescribe system to simulate the relativistic quantum
effect. We quantum simulate the Dirac fermion mode, Majorana fermion mode and
Majorana-Weyl fermion mode and a crossover between them in cavity QED lattice.
We also present the different analytical relations between the field operators
for different mode excitations.Comment: 7 pages, Comments are welcome. arXiv admin note: substantial text
overlap with arXiv:1309.774
Different resource management policies in multi-mode resource constrained multi-project scheduling
This study investigates different resource management policies in resource constrained multi-project problem environments. The problem environment under investigation has alternative modes for activities, a set of renewable and nonrenewable resources used by activities and further considerations such as general resource budget. The characterization of the way resources are used by individual projects in the multiproject environment is called resource management policy in this study. The solution approaches in the literature for multi-project problems generally defines the resources as a pool that can be shared by all the projects which in fact creates a general assumption for the resource usage characteristics. This resource management policy is referred as resource sharing policy in this study. Resource sharing policy can be invalid in
some certain cases where sharing assumption is not feasible because of some characteristics of resources and/or projects which require different resource management policies for the multi-project environment. According to the characteristics of resources and projects, resource management policies such as
resource dedication, relaxed resource dedication and generalized resource management policies can be defined. In this paper, these resource management policies will be defined and their mathematical formulations will be presented and discussed
Rotational Splitting of Pulsational Modes
Mode splittings produced by uniform rotation and a particular form of
differential rotation are computed for two-dimensional rotating 10 Mo ZAMS
stellar models. The change in the character of the mode splitting is traced as
a function of uniform rotation rate, and it is found that only relatively slow
rotation rates are required before the mode splitting becomes asymmetric about
the azimuthally symmetric (m=0) mode. Increased rotation produces a
progressively altered pattern of the individual modes with respect to each
other. Large mode splittings begin to overlap with the mode splittings produced
by different radial and latitudinal modes at relatively low rotation rates. The
mode splitting pattern for the differentially rotating stars we model is
different than that for uniformly rotating stars, making the mode splitting a
possible discriminant of the internal angular momentum distribution if one
assumes the formidable challenge of mode identification can be overcome.Comment: 6 journal pages, 7 Figures, accepted by Ap
Estimating nonresponse bias and mode effects in a mixed mode survey
In mixed-mode surveys, it is difficult to separate sample selection differences from mode-effects that can occur when respondents respond in different interview settings. This paper provides a framework for separating mode-effects from selection effects by matching very similar respondents from different survey modes using propensity score matching. The answer patterns of the matched respondents are subsequently compared. We show that matching can explain differences in nonresponse and coverage in two Internet-samples. When we repeat this procedure for a telephone and Internet-sample however, differences persist between the samples after matching. This indicates the occurrence of mode-effects in telephone and Internet surveys. Mode-effects can be problematic; hence we conclude with a discussion of designs that can be used to explicitly study mode-effects
A thermodynamically consistent derivation of a frictional-damage cohesive-zone model with different mode i and mode II fracture energies
The present paper deals with the derivation of an interface model characterized by macroscopic fracture energies which are different in modes I and II, the macroscopic fracture energy being the total energy dissipated per unit of fracture area. It is first shown that thermo-dynamical consistency for a model governed by a single damage variable, combined with the choice of employing an equivalent relative displacement and of a linear softening in the stress-relative displacement law, leads to the coincidence of fracture energies in modes I and II. To retrieve the experimental evidence of a greater fracture energy in mode II, a micro-structured geometry is considered at the typical point of the interface where a Representative Interface Element (RIE) characterized by a periodic arrangement of distinct inclined planes is introduced. The interaction within each of these surfaces is governed by a coupled damage-friction law. A sensitivity analysis of the correlation between micromechanical parameters and the numerically computed single-point microstructural response in mode II is reported. An assessment of the capability of the model in predicting different mixed mode fracture energies is carried out both at the single microstructural interface point level and with a structural example. For the latter a double cantilever beam with uneven bending moments has been analyzed and numerical results are compared with experimental data reported in the literature for different values of mode mixity. © 2014 Elsevier Masson SAS. All rights reserved
Double-resonant fast particle-wave interaction
In future fusion devices fast particles must be well confined in order to
transfer their energy to the background plasma. Magnetohydrodynamic
instabilities like Toroidal Alfv\'en Eigenmodes or core-localized modes such as
Beta Induced Alfv\'en Eigenmodes and Reversed Shear Alfv\'en Eigenmodes, both
driven by fast particles, can lead to significant losses. This is observed in
many ASDEX Upgrade discharges. The present study applies the drift-kinetic
HAGIS code with the aim of understanding the underlying resonance mechanisms,
especially in the presence of multiple modes with different frequencies. Of
particular interest is the resonant interaction of particles simultaneously
with two different modes, referred to as 'double-resonance'. Various mode
overlapping scenarios with different q profiles are considered. It is found
that, depending on the radial mode distance, double-resonance is able to
enhance growth rates as well as mode amplitudes significantly. Surprisingly, no
radial mode overlap is necessary for this effect. Quite the contrary is found:
small radial mode distances can lead to strong nonlinear mode stabilization of
a linearly dominant mode.Comment: 12 pages, 11 figures; Nuclear Fusion 52 (2012
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