3,242 research outputs found
Data compression for near Earth and deep space to Earth transmission
Key issues of data compression for near Earth and deep space to Earth transmission discussion group are briefly presented. Specific recommendations as made by the group are as follows: (1) since data compression is a cost effective way to improve communications and storage capacity, NASA should use lossless data compression wherever possible; (2) NASA should conduct experiments and studies on the value and effectiveness of lossy data compression; (3) NASA should develop and select approaches to high ratio compression of operational data such as voice and video; (4) NASA should develop data compression integrated circuits for a few key approaches identified in the preceding recommendation; (5) NASA should examine new data compression approaches such as combining source and channel encoding, where high payoff gaps are identified in currently available schemes; and (6) users and developers of data compression technologies should be in closer communication within NASA and with academia, industry, and other government agencies
A System for Acquiring, Processing, and Rendering Panoramic Light Field Stills for Virtual Reality
We present a system for acquiring, processing, and rendering panoramic light
field still photography for display in Virtual Reality (VR). We acquire
spherical light field datasets with two novel light field camera rigs designed
for portable and efficient light field acquisition. We introduce a novel
real-time light field reconstruction algorithm that uses a per-view geometry
and a disk-based blending field. We also demonstrate how to use a light field
prefiltering operation to project from a high-quality offline reconstruction
model into our real-time model while suppressing artifacts. We introduce a
practical approach for compressing light fields by modifying the VP9 video
codec to provide high quality compression with real-time, random access
decompression.
We combine these components into a complete light field system offering
convenient acquisition, compact file size, and high-quality rendering while
generating stereo views at 90Hz on commodity VR hardware. Using our system, we
built a freely available light field experience application called Welcome to
Light Fields featuring a library of panoramic light field stills for consumer
VR which has been downloaded over 15,000 times.Comment: 15 pages, 14 figures, 2 tables, accepted by SIGGRAPH Asia 2018,
low-resolution versio
Families of Bianchi modular symbols: critical base-change p-adic L-functions and p-adic Artin formalism
Let be an imaginary quadratic field. In this article, we study the
eigenvariety for GL(2)/K, proving an etaleness result for the weight map at
non-critical classical points and a smoothness result at base-change classical
points. We give three main applications of this; let be a regular
-stabilised newform of weight at least 2 without CM by . (1) We
construct a two-variable -adic -function attached to the base-change of
to under assumptions on that we conjecture always hold, in
particular making no assumption on the slope of . (2) We construct
three-variable -adic -functions over the eigenvariety interpolating the
-adic -functions of classical base-change Bianchi cusp forms in families.
(3) We prove that these base-change -adic -functions satisfy a -adic
Artin formalism result, that is, they factorise in the same way as the
classical -function under Artin formalism.
In an appendix, Carl Wang-Erickson describes a base-change deformation
functor and gives a characterisation of its Zariski tangent space.Comment: 26 pages, with a 3 page appendix by Carl Wang-Erickson. Comments
welcome! Changes for v5: added contents, minor changes to exposition. v4:
corrected funding acknowledgements. v3: This version has a new introduction,
has been reorganised and greatly shortened, and incorporates minor
corrections. v2: minor correction
The European Commission's public consultation on the review of EU copyright rules: a response by the CREATe Centre
No abstract available
Some acoustic and articulatory correlates of phrasal stress in Spanish
All spoken languages show rhythmic patterns. Recent work
with a number of different languages (English, Japanese,
Mandarin Chinese, and French) suggests that metrically
(hierarchically) assigned stress levels of the utterance show
strong correlations with the amount of jaw displacement, and
corresponding F1 values. This paper examines some
articulatory and acoustic correlates of Spanish rhythm;
specifically, we ask if there is a correlation between phrasal
stress values metrically assigned to each syllable and
acoustic/articulatory values. We used video recordings of
three Salvadoran Spanish speakers to measure maximum jaw displacement, mean F0, mean intensity, mean duration, and
mid-vowel F1 for each vowel in two Spanish sentences. The results show strong correlations between stress and duration,
and between stress and F1, but weak correlations between stress and both mean vowel intensity and maximum jaw displacement. We also found weak correlations between jaw displacement and both mean vowel intensity and F1
LSP Composite Susbtrate Destructive Evaluation Test Assessment Manual
This document specifies the processes to perform post-strike destructive damage evaluation of tested CFRP panels.It is recognized that many factors besides lightning damage protection are involved in the selection of an appropriate Lightning Strike Protection (LSP) for a particular system (e.g., cost, weight, corrosion resistance, shielding effectiveness, etc.). This document strives primarily to address the standardized generation of damage protection performance data
A high resolution line survey of IRC+10216 with Herschel. First results: Detection of warm silicon dicarbide SiC2
We present the first results of a high-spectral-resolution survey of the
carbon-rich evolved star IRC+10216 that was carried out with the HIFI
spectrometer onboard Herschel. This survey covers all HIFI bands, with a
spectral range from 488 to 1901GHz. In this letter we focus on the band-1b
spectrum, in a spectral range 554.5-636.5GHz, where we identified 130 spectral
features with intensities above 0.03 K and a signal-to-noise ratio >5. Detected
lines arise from HCN, SiO, SiS, CS, CO, metal-bearing species and,
surprisingly, silicon dicarbide (SiC2). We identified 55 SiC2 transitions
involving energy levels between 300 and 900 K. By analysing these rotational
lines, we conclude that SiC2 is produced in the inner dust formation zone, with
an abundance of ~2x10^-7 relative to molecular hydrogen. These SiC2 lines have
been observed for the first time in space and have been used to derive an SiC2
rotational temperature of ~204 K and a source-averaged column density of
~6.4x10^15 cm^-2. Furthermore, the high quality of the HIFI data set was used
to improve the spectroscopic rotational constants of SiC2.Comment: A&A HIFI Special Issue, 201
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