2,696 research outputs found
Sky maps without anisotropies in the cosmic microwave background are a better fit to WMAP's uncalibrated time ordered data than the official sky maps
The purpose of this reanalysis of the WMAP uncalibrated time ordered data
(TOD) was two fold. The first was to reassess the reliability of the detection
of the anisotropies in the official WMAP sky maps of the cosmic microwave
background (CMB). The second was to assess the performance of a proposed
criterion in avoiding systematic error in detecting a signal of interest. The
criterion was implemented by testing the null hypothesis that the uncalibrated
TOD was consistent with no anisotropies when WMAP's hourly calibration
parameters were allowed to vary. It was shown independently for all 20 WMAP
channels that sky maps with no anisotropies were a better fit to the TOD than
those from the official analysis. The recently launched Planck satellite should
help sort out this perplexing result.Comment: 11 pages with 1 figure and 2 tables. Extensively rewritten to explain
the research bette
Early Country Musician Doc Williams (1914-2011): Contributions to the Development of Country Music and Applications for a General Music Curriculum, Grades 3-5
The purpose of this study is to document early country musician Doc Williams’ musical career, to evaluate his specific contributions to early country music from 1932 to 1951, and to develop curriculum materials for grades 3-5 general music classes based on his music. I chose 1951 as the end point for this study because at that time Williams began frequent tours to the northeast and Canada. These later years, although worthy of attention, launched a new phase of his career, beyond the scope of this study. During the course of the study, I address the following questions: 1) What was the nature of Williams’ musical education and development as a musician? 2) What are his contributions to country music? 3) In what ways can Williams’ music be used in a general music curriculum for grades 3-5? Doc Williams was born Andrew Smik Jr. in Cleveland, Ohio, on June 26, 1914. He began his life-long musical career playing country music on radio in 1932. His success on WWVA’s “Wheeling Jamboree” contributed to his popularity in the Northeast and throughout Canada. Williams’ practices in country music are the reason many regard him as a pioneer of country music. Radio broadcasts, personal appearances, songwriting, song publishing, and recording were all important components of his life-long career. His music is exemplary of the early country music genre. Therefore, his contributions to early country music make his music worthy of study. Historically, country music has been marginalized in the music curriculum. This study demonstrates the relevance and value of early country music such as that of Williams in a general music curriculum.Master of ArtsMusic EducationUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/123006/1/Josephine_Cover-Masters_Thesis.pd
Characterization of Collective Gaussian Attacks and Security of Coherent-State Quantum Cryptography
We provide a simple description of the most general collective Gaussian
attack in continuous-variable quantum cryptography. In the scenario of such
general attacks, we analyze the asymptotic secret-key rates which are
achievable with coherent states, joint measurements of the quadratures and
one-way classical communication.Comment: 4 pages, 1 figure + 1 Table, REVteX. More descriptive titl
A variational principle for cyclic polygons with prescribed edge lengths
We provide a new proof of the elementary geometric theorem on the existence
and uniqueness of cyclic polygons with prescribed side lengths. The proof is
based on a variational principle involving the central angles of the polygon as
variables. The uniqueness follows from the concavity of the target function.
The existence proof relies on a fundamental inequality of information theory.
We also provide proofs for the corresponding theorems of spherical and
hyperbolic geometry (and, as a byproduct, in spacetime). The spherical
theorem is reduced to the euclidean one. The proof of the hyperbolic theorem
treats three cases separately: Only the case of polygons inscribed in compact
circles can be reduced to the euclidean theorem. For the other two cases,
polygons inscribed in horocycles and hypercycles, we provide separate
arguments. The hypercycle case also proves the theorem for "cyclic" polygons in
spacetime.Comment: 18 pages, 6 figures. v2: typos corrected, final versio
Generalized relation between the relative entropy and dissipation for nonequilibrium systems
Recently, Kawai, Parrondo, and Van den Broeck have related dissipation to
time-reversal asymmetry. We generalized the result by considering a protocol
where the physical system is driven away from an initial thermal equilibrium
state with temperature to a final thermal equilibrium state at a
different temperature. We illustrate the result using a model with an exact
solution, i.e., a particle in a moving one-dimensional harmonic well.Comment: 4 page
Note on exponential families of distributions
We show that an arbitrary probability distribution can be represented in
exponential form. In physical contexts, this implies that the equilibrium
distribution of any classical or quantum dynamical system is expressible in
grand canonical form.Comment: 5 page
Parameter estimation in pair hidden Markov models
This paper deals with parameter estimation in pair hidden Markov models
(pair-HMMs). We first provide a rigorous formalism for these models and discuss
possible definitions of likelihoods. The model being biologically motivated,
some restrictions with respect to the full parameter space naturally occur.
Existence of two different Information divergence rates is established and
divergence property (namely positivity at values different from the true one)
is shown under additional assumptions. This yields consistency for the
parameter in parametrization schemes for which the divergence property holds.
Simulations illustrate different cases which are not covered by our results.Comment: corrected typo
How much measurement independence is needed in order to demonstrate nonlocality?
If nonlocality is to be inferred from a violation of Bell's inequality, an
important assumption is that the measurement settings are freely chosen by the
observers, or alternatively, that they are random and uncorrelated with the
hypothetical local variables. We study the case where this assumption is
weakened, so that measurement settings and local variables are at least
partially correlated. As we show, there is a connection between this type of
model and models which reproduce nonlocal correlations by allowing classical
communication between the distant parties, and a connection with models that
exploit the detection loophole. We show that even if Bob's choices are
completely independent, all correlations obtained from projective measurements
on a singlet can be reproduced, with the correlation (measured by mutual
information) between Alice's choice and local variables less than or equal to a
single bit.Comment: 5 pages, 1 figure. v2 Various improvements in presentation. Results
unchange
Scanner Invariant Representations for Diffusion MRI Harmonization
Purpose: In the present work we describe the correction of diffusion-weighted
MRI for site and scanner biases using a novel method based on invariant
representation.
Theory and Methods: Pooled imaging data from multiple sources are subject to
variation between the sources. Correcting for these biases has become very
important as imaging studies increase in size and multi-site cases become more
common. We propose learning an intermediate representation invariant to
site/protocol variables, a technique adapted from information theory-based
algorithmic fairness; by leveraging the data processing inequality, such a
representation can then be used to create an image reconstruction that is
uninformative of its original source, yet still faithful to underlying
structures. To implement this, we use a deep learning method based on
variational auto-encoders (VAE) to construct scanner invariant encodings of the
imaging data.
Results: To evaluate our method, we use training data from the 2018 MICCAI
Computational Diffusion MRI (CDMRI) Challenge Harmonization dataset. Our
proposed method shows improvements on independent test data relative to a
recently published baseline method on each subtask, mapping data from three
different scanning contexts to and from one separate target scanning context.
Conclusion: As imaging studies continue to grow, the use of pooled multi-site
imaging will similarly increase. Invariant representation presents a strong
candidate for the harmonization of these data
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