7,996 research outputs found
Random Matrices with Correlated Elements: A Model for Disorder with Interactions
The complicated interactions in presence of disorder lead to a correlated
randomization of states. The Hamiltonian as a result behaves like a
multi-parametric random matrix with correlated elements. We show that the
eigenvalue correlations of these matrices can be described by the single
parametric Brownian ensembles. The analogy helps us to reveal many important
features of the level-statistics in interacting systems e.g. a critical point
behavior different from that of non-interacting systems, the possibility of
extended states even in one dimension and a universal formulation of level
correlations.Comment: 19 Pages, No Figures, Major Changes to Explain the Mathematical
Detail
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The Extent of Autism Knowledge of Novice Alternatively Certified Special Education Teachers in Texas
An increase in the prevalence rate of autism is not necessarily matched by a concurrent increase in the rate of highly qualified special education teachers, resulting in chronic teacher shortages in this area. Alternative certification (AC) is used as a mechanism to alleviate the demand for highly qualified special education teachers. However, AC routes have often left novice teachers underprepared for teaching students with autism, more specifically in the implementation of evidence-based practices necessary for instructional effectiveness. The purpose of the study was to assess the knowledge of novice AC teachers in the area of autism intervention and to determine the extent to which demographic, educational and professional factors predict the variance in knowledge scores. Data were collected through an electronic survey instrument disseminated to all novice (i.e., first-and second-year) alternatively certified special education teachers in the state of Texas. Results indicated that AC teachers were not adequately knowledgeable about autism and the largest predictor of autism knowledge was hours engaged in self-directed learning. Implications for improving the quality of AC programs in Texas are discussed
Computational Investigation of Furnace Wall for Silica Ramming Mass with FDM
Furnaces are useful for melting different materials for casting process. In this research paper, we had done advanced heat transfer analysis of induction furnace wall made of silica ramming mass using explicit finite difference method. We have divided actual geometry of furnace refractory wall into 14 elements and 24 nodes. We have derived explicit finite difference equations for all 24 nodes. We have calculated temperature distribution and thermal stress distribution for all different nodes with respect to time. We have plotted graphs for maximum temperature v/s time and maximum stress v/s time. We found that results indicate the effect of thermal fatigue in the induction furnace wall for silica ramming mass. The analysis is very helpful in understanding how thermal fatigue failure of refractory wall happens
Towards a common thread in Complexity: an accuracy-based approach
The complexity of a system, in general, makes it difficult to determine some
or almost all matrix elements of its operators. The lack of accuracy acts as a
source of randomness for the matrix elements which are also subjected to an
external potential due to existing system conditions. The fluctuation of
accuracy due to varying system-conditions leads to a diffusion of the matrix
elements. We show that, for the single well potentials, the diffusion can be
described by a common mathematical formulation where system information enters
through a single parameter. This further leads to a characterization of
physical properties by an infinite range of single parametric universality
classes
Thermodynamics of protein folding: a random matrix formulation
The process of protein folding from an unfolded state to a biologically
active, folded conformation is governed by many parameters e.g the sequence of
amino acids, intermolecular interactions, the solvent, temperature and chaperon
molecules. Our study, based on random matrix modeling of the interactions,
shows however that the evolution of the statistical measures e.g Gibbs free
energy, heat capacity, entropy is single parametric. The information can
explain the selection of specific folding pathways from an infinite number of
possible ways as well as other folding characteristics observed in computer
simulation studies.Comment: 21 Pages, no figure
Multi-Channel Transport in Disordered Medium under Generic Scattering Conditions
Our study of the evolution of transmission eigenvalues, due to changes in
various physical parameters in a disordered region of arbitrary dimensions,
results in a generalization of the celebrated DMPK equation. The evolution is
shown to be governed by a single complexity parameter which implies a deep
level of universality of transport phenomena through a wide range of disordered
regions. We also find that the interaction among eigenvalues is of many body
type that has important consequences for the statistical behavior of transport
properties.Comment: 19 Pages, No Figure
Universal Level dynamics of Complex Systems
. We study the evolution of the distribution of eigenvalues of a
matrix subject to a random perturbation drawn from (i) a generalized Gaussian
ensemble (ii) a non-Gaussian ensemble with a measure variable under the change
of basis. It turns out that, in the case (i), a redefinition of the parameter
governing the evolution leads to a Fokker-Planck equation similar to the one
obtained when the perturbation is taken from a standard Gaussian ensemble (with
invariant measure). This equivalence can therefore help us to obtain the
correlations for various physically-significant cases modeled by generalized
Gaussian ensembles by using the already known correlations for standard
Gaussian ensembles.
For large -values, our results for both cases (i) and (ii) are similar to
those obtained for Wigner-Dyson gas as well as for the perturbation taken from
a standard Gaussian ensemble. This seems to suggest the independence of
evolution, in thermodynamic limit, from the nature of perturbation involved as
well as the initial conditions and therefore universality of dynamics of the
eigenvalues of complex systems.Comment: 11 Pages, Latex Fil
Higher Order Correlations in Quantum Chaotic Spectra
The statistical properties of the quantum chaotic spectra have been studied,
so far, only up to the second order correlation effects. The numerical as well
as the analytical evidence that random matrix theory can successfully model the
spectral fluctuatations of these systems is available only up to this order.
For a complete understanding of spectral properties it is highly desirable to
study the higher order spectral correlations. This will also inform us about
the limitations of random matrix theory in modelling the properties of quantum
chaotic systems. Our main purpose in this paper is to carry out this study by a
semiclassical calculation for the quantum maps; however results are also valid
for time-independent systems.Comment: Revtex, Four figures (Postscript files), Phys. Rev E (in press
A Survey of Word Reordering Model in Statistical Machine Translation
Machine translation is the process of translating one natural language in to another natural language by computers. In statistical machine translation word reordering is a big challenge between distant language pair. It is important factor for its quality and efficiency. Word reordering is major challenge For Indian languages who have big structural difference like English and Hindi language. This paper present description about statistical machine translation, reordering model and reordering types
Toward semiclassical theory of quantum level correlations of generic chaotic systems
In the present work we study the two-point correlation function
of the quantum mechanical spectrum of a classically chaotic system. Recently
this quantity has been computed for chaotic and for disordered systems using
periodic orbit theory and field theory. In this work we present an independent
derivation, which is based on periodic orbit theory. The main ingredient in our
approach is the use of the spectral zeta function and its autocorrelation
function . The relation between and is
constructed by making use of a probabilistic reasoning similar to that which
has been used for the derivation of Hardy -- Littlewood conjecture. We then
convert the symmetry properties of the function into relations
between the so-called diagonal and the off-diagonal parts of . Our
results are valid for generic systems with broken time reversal symmetry, and
with non-commensurable periods of the periodic orbits.Comment: 15 pages(twocolumn format), LaTeX, EPSF, (figures included
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