11,297 research outputs found
Factorization of completely bounded bilinear operators and injectivity
We characterize injectivity of von Neumann algebras in terms of factoring
bilinear maps as products of linear maps.Comment: 32 pages. See also http://www.math.tamu.edu/~roger.smith/
preprints.htm
Cut loci and conjugate loci on Liouville surfaces
In the earlier paper (Itoh and Kiyohara, Manuscr Math 114:247ā264, 2004), we showed that the cut locus of a general point on two-dimensional ellipsoid is a segment of a curvature line and proved "Jacobiās last geometric statement" on the singularities of the conjugate locus. In the present paper,we showthat a wider class of Liouville surfaces possess such simple cut loci and conjugate loci. The results include the determination of cut loci and the set of poles on two-sheeted hyperboloids and elliptic paraboloids
Strong singularity for subalgebras of finite factors
In this paper we develop the theory of strongly singular subalgebras of von
Neumann algebras, begun in earlier work. We mainly examine the situation of
type \tto factors arising from countable discrete groups. We give simple
criteria for strong singularity, and use them to construct strongly singular
subalgebras. We particularly focus on groups which act on geometric objects,
where the underlying geometry leads to strong singularity
An Australia telescope survey for CMB anisotropies
We have surveyed six distinct `empty fields' using the Australia Telescope
Compact Array in an ultra-compact configuration with the aim of imaging, with a
high brightness sensitivity, any arcmin-scale brightness-temperature
anisotropies in the background radio sky. The six well-separated regions were
observed at a frequency of 8.7 GHz and the survey regions were limited by the
ATCA primary beams which have a full width at half maximum of 6 arcmin at this
frequency; all fields were observed with a resolution of 2 arcmin and an rms
thermal noise of 24 microJy/beam. After subtracting foreground confusion
detected in higher resolution images of the fields, residual fluctuations in
Stokes I images are consistent with the expectations from thermal noise and
weaker (unidentified) foreground sources; the Stokes Q and U images are
consistent with expectations from thermal noise.
Within the sensitivity of our observations, we have no reason to believe that
there are any Sunyaev-Zeldovich holes in the microwave sky surveyed. Assuming
Gaussian-form CMB anisotropy with a `flat' spectrum, we derive 95 per cent
confidence upper limits of Q_flat < 10--11 microK in polarized intensity and
Q_flat < 25 microK in total intensity. The ATCA filter function peaks at l=4700
and has half maximum values at l=3350 and 6050.Comment: 17 pages, includes 8 figures and 6 tables, accepted for publication
in MNRA
Ultra-dense magnetoresistive mass memory
This report details the progress and accomplishments of Nonvolatile Electronics (NVE), Inc., on the design of the wafer scale MRAM mass memory system during the fifth quarter of the project. NVE has made significant progress this quarter on the one megabit design in several different areas. A test chip, which will verify a working GMR bit with the dimensions required by the 1 Meg chip, has been designed, laid out, and is currently being processed in the NVE labs. This test chip will allow electrical specifications, tolerances, and processing issues to be finalized before construction of the actual chip, thus providing a greater assurance of success of the final 1 Meg design. A model has been developed to accurately simulate the parasitic effects of unselected sense lines. This model gives NVE the ability to perform accurate simulations of the array electronic and test different design concepts. Much of the circuit design for the 1 Meg chip has been completed and simulated and these designs are included. Progress has been made in the wafer scale design area to verify the reliable operation of the 16 K macrocell. This is currently being accomplished with the design and construction of two stand alone test systems which will perform life tests and gather data on reliabiliy and wearout mechanisms for analysis
Neutron capture rates and r-process nucleosynthesis
Simulations of r-process nucleosynthesis require nuclear physics information
for thousands of neutron-rich nuclear species from the line of stability to the
neutron drip line. While arguably the most important pieces of nuclear data for
the r-process are the masses and beta decay rates, individual neutron capture
rates can also be of key importance in setting the final r-process abundance
pattern. Here we consider the influence of neutron capture rates in forming the
A~80 and rare earth peaks.Comment: 10 pages, 5 figures, appears in the Proceedings of the 14th
International Symposium on Capture Gamma-Ray Spectroscopy and Related Topic
S-band omnidirectional antenna for the SERT-C satellite
The program to design an S-band omnidirectional antenna system for the SERT-C spacecraft is discussed. The program involved the tasks of antenna analyses by computer techniques, scale model radiation pattern measurements of a number of antenna systems, full-scale RF measurements, and the recommended design, including detailed drawings. A number of antenna elements were considered: the cavity-backed spiral, quadrifilar helix, and crossed-dipoles were chosen for in-depth studies. The final design consisted of a two-element array of cavity-backed spirals mounted on opposite sides of spacecraft and fed in-phase through a hybrid junction. This antenna system meets the coverage requirement of having a gain of at least minus 10 dBi over 50 percent of a 4 pi steradian sphere with the solar panels in operation. This coverage level is increased if the ground station has the capability to change polarization
Simulations of a Scintillator Compton Gamma Imager for Safety and Security
We are designing an all-scintillator Compton gamma imager for use in security
investigations and remediation actions involving radioactive threat material.
To satisfy requirements for a rugged and portable instrument, we have chosen
solid scintillator for the active volumes of both the scatter and absorber
detectors. Using the BEAMnrc/EGSnrc Monte Carlo simulation package, we have
constructed models using four different materials for the scatter detector:
LaBr_3, NaI, CaF_2 and PVT. We have compared the detector performances using
angular resolution, efficiency, and image resolution. We find that while PVT
provides worse performance than that of the detectors based entirely on
inorganic scintillators, all of the materials investigated for the scatter
detector have the potential to provide performance adequate for our purposes.Comment: Revised text and figures, Presented at SORMA West 2008, Published in
IEEE Transactions on Nuclear Scienc
Is Information Density Uniform in Task-Oriented Dialogues?
Acknowledgements We would like to thank Jaap Jumelet for a helpful discussion on neural language models, the anonymous EMNLP-2021 reviewers for their valuable comments, as well as the anonymous ACL-2021 reviewers for feedback that led to a considerable improvement of the first version of this paper. This project has received funding from the European Research Council (ERC) under the European Unionās Horizon 2020 research and innovation programme (grant agreement No. 819455).Publisher PD
- ā¦