8,093 research outputs found
PRINCIPLES AND TECHNIQUES LEARNED FROM THE IOWA PUBLIC POLICY EDUCATION PROJECT
Teaching/Communication/Extension/Profession,
Beyond universality in random matrix theory
In order to have a better understanding of finite random matrices with
non-Gaussian entries, we study the expansion of local eigenvalue
statistics in both the bulk and at the hard edge of the spectrum of random
matrices. This gives valuable information about the smallest singular value not
seen in universality laws. In particular, we show the dependence on the fourth
moment (or the kurtosis) of the entries. This work makes use of the so-called
complex Gaussian divisible ensembles for both Wigner and sample covariance
matrices.Comment: Published at http://dx.doi.org/10.1214/15-AAP1129 in the Annals of
Applied Probability (http://www.imstat.org/aap/) by the Institute of
Mathematical Statistics (http://www.imstat.org
Density of States of Quantum Spin Systems from Isotropic Entanglement
We propose a method which we call "Isotropic Entanglement" (IE), that
predicts the eigenvalue distribution of quantum many body (spin) systems (QMBS)
with generic interactions. We interpolate between two known approximations by
matching fourth moments. Though, such problems can be QMA-complete, our
examples show that IE provides an accurate picture of the spectra well beyond
what one expects from the first four moments alone. We further show that the
interpolation is universal, i.e., independent of the choice of local terms.Comment: 4+ pages, content is as in the published versio
Process development of shaped magnesium- lithium castings
Casting process development for ternary magnesium- lithium-silicon allo
Statistical eigen-inference from large Wishart matrices
We consider settings where the observations are drawn from a zero-mean
multivariate (real or complex) normal distribution with the population
covariance matrix having eigenvalues of arbitrary multiplicity. We assume that
the eigenvectors of the population covariance matrix are unknown and focus on
inferential procedures that are based on the sample eigenvalues alone (i.e.,
"eigen-inference"). Results found in the literature establish the asymptotic
normality of the fluctuation in the trace of powers of the sample covariance
matrix. We develop concrete algorithms for analytically computing the limiting
quantities and the covariance of the fluctuations. We exploit the asymptotic
normality of the trace of powers of the sample covariance matrix to develop
eigenvalue-based procedures for testing and estimation. Specifically, we
formulate a simple test of hypotheses for the population eigenvalues and a
technique for estimating the population eigenvalues in settings where the
cumulative distribution function of the (nonrandom) population eigenvalues has
a staircase structure. Monte Carlo simulations are used to demonstrate the
superiority of the proposed methodologies over classical techniques and the
robustness of the proposed techniques in high-dimensional, (relatively) small
sample size settings. The improved performance results from the fact that the
proposed inference procedures are "global" (in a sense that we describe) and
exploit "global" information thereby overcoming the inherent biases that
cripple classical inference procedures which are "local" and rely on "local"
information.Comment: Published in at http://dx.doi.org/10.1214/07-AOS583 the Annals of
Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical
Statistics (http://www.imstat.org
Utilization of NASA Lewis mobile terminals for the Hermes satellite
The high power of the Hermes satellite enables two-way television and voice communication with small ground terminals. The Portable Earth Terminal (PET) and the Transportable Earth Terminal (TET) were developed and built by NASA-Lewis to provide communications capability to short-term users. The NASA-Lewis mobile terminals are described in terms of vehicles and onboard equipment, as well as operation aspects, including use in the field. The section on demonstrations divides the uses into categories of medicine, education, technology and government. Applications of special interest within each category are briefly described
A Preliminary Study of the Economic Implications From Court Service Delivery Consolidation in Rural Iowa: Phase I Report
This report .is designed-to foster discussion among citizens, leaders and policymakers regarding an important public Issue of concern to lowans. Iowa State University seeks to providie accurate research-based information on relevant issues and neither endorses nor opposes proposals regarding the issues analyzed. The research contained-herein was. conducted with partial, support from^ the Iowa Agriculture and:Home Economics Experiment Station :(TAHEES), the Iowa Cooperative \u27Extension Service ,(CES). and funding frbm local officials in 40 Iowa counties.collected by. Rural. Counties Against Regionalization (RCAR). RCAR funding was solely-used for funding research assistance with the understanding that the goal of the project was to develop objective, information sources for making \u27 \u27 reasonable judgements regarding consolidation issues. The project director expressedly avoided\u27 receiving financial gain from the project so as to prevent conflicts of interest, bias in research, and/or\u27any appearance thereof^
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