6,356 research outputs found
Achieving Good Angular Resolution in 3D Arc Diagrams
We study a three-dimensional analogue to the well-known graph visualization
approach known as arc diagrams. We provide several algorithms that achieve good
angular resolution for 3D arc diagrams, even for cases when the arcs must
project to a given 2D straight-line drawing of the input graph. Our methods
make use of various graph coloring algorithms, including an algorithm for a new
coloring problem, which we call localized edge coloring.Comment: 12 pages, 5 figures; to appear at the 21st International Symposium on
Graph Drawing (GD 2013
Star Formation Rate Indicators in Wide-Field Infrared Survey Preliminary Release
With the goal of investigating the degree to which theMIR luminosity in
theWidefield Infrared Survey Explorer (WISE) traces the SFR, we analyze 3.4,
4.6, 12 and 22 {\mu}m data in a sample of {\guillemotright} 140,000
star-forming galaxies or star-forming regions covering a wide range in
metallicity 7.66 < 12 + log(O/H) < 9.46, with redshift z < 0.4. These
star-forming galaxies or star-forming regions are selected by matching the WISE
Preliminary Release Catalog with the star-forming galaxy Catalog in SDSS DR8
provided by JHU/MPA 1.We study the relationship between the luminosity at 3.4,
4.6, 12 and 22 {\mu}m from WISE and H\alpha luminosity in SDSS DR8. From these
comparisons, we derive reference SFR indicators for use in our analysis. Linear
correlations between SFR and the 3.4, 4.6, 12 and 22 {\mu}m luminosity are
found, and calibrations of SFRs based on L(3.4), L(4.6), L(12) and L(22) are
proposed. The calibrations hold for galaxies with verified spectral
observations. The dispersion in the relation between 3.4, 4.6, 12 and 22 {\mu}m
luminosity and SFR relates to the galaxy's properties, such as 4000 {\deg}A
break and galaxy color.Comment: 10 pages, 3 figure
A three dimensional extinction map of the Galactic Anticentre from multi-band photometry
We present a three dimensional extinction map in band. The map has a
spatial angular resolution, depending on latitude, between 3 -- 9\,arcmin and
covers the entire XSTPS-GAC survey area of over 6,000\, for Galactic
longitude and latitude . By cross-matching the photometric catalog of the Xuyi Schmidt
Telescope Photometric Survey of the Galactic Anticentre (XSTPS-GAC) with those
of 2MASS and WISE, we have built a multi-band photometric stellar sample of
about 30 million stars and applied spectral energy distribution (SED) fitting
to the sample. By combining photometric data from the optical to the
near-infrared, we are able to break the degeneracy between the intrinsic
stellar colours and the amounts of extinction by dust grains for stars with
high photometric accuracy, and trace the extinction as a function of distance
for low Galactic latitude and thus highly extincted regions. This has allowed
us to derive the best-fit extinction and distance information of more than 13
million stars, which are used to construct the three dimensional extinction
map. We have also applied a Rayleigh-Jeans colour excess (RJCE) method to the
data using the 2MASS and WISE colour . The resulting RJCE extinction
map is consistent with the integrated two dimensional map deduced using the
best-fit SED algorithm. However for individual stars, the amounts of extinction
yielded by the RJCE method suffer from larger errors than those given by the
best-fit SED algorithm.Comment: 20 pages, 18 figures, accepted in MNRA
Fatigue performance of laser welds in heavy-gage press hardening steels
This work investigates and compares the fatigue performance of laser-welded joints of two press hardening steels: a standard 22MnB5 and a variant modified by a combination of niobium and molybdenum (NbMo) alloying. The results indicate that joint geometry aspects, superposed to an intrusion-generated damage mechanism, were prevalent in causing a poor fatigue life in the case of peak stress values greater than 11% of the base metal's ultimate strength being around 1450 MPa. As identical process procedures were employed, the tests allowed investigating the influence of the alloy design on fatigue performance. The results of geometrical analysis and fatigue tests indicated that the NbMo modified alloy performed better than the standard 22MnB5 steel. The results also suggest that, if extremely tight quality limits are used in the manufacturing procedures, laser-welded joints of press hardened steels could offer a very favorable fatigue performance being considerably better than that of conventional and high strength structural steels
Quantitative Performance Assessment of LiDAR-based Vehicle Contour Estimation Algorithms for Integrated Vehicle Safety Applications
Many nations and organizations are committing to achieving the goal of `Vision Zero\u27 and eliminate road traffic related deaths around the world. Industry continues to develop integrated safety systems to make vehicles safer, smarter and more capable in safety critical scenarios. Passive safety systems are now focusing on pre-crash deployment of restraint systems to better protect vehicle passengers. Current commonly used bounding box methods for shape estimation of crash partners lack the fidelity required for edge case collision detection and advanced crash modeling. This research presents a novel algorithm for robust and accurate contour estimation of opposing vehicles. The presented method is evaluated via a developed framework for key performance metrics and compared to alternative algorithms found in literature
The Maser-emitting Structure and Time Variability of the SiS Lines J =14-13 and 15-14 in IRC+10216
2 pags., 1 tab. -- Why Galaxies Care About AGB Stars: A Continuing Challenge through Cosmic Time Proceedings IAU Symposium No. 343, 2019
F. Kerschbaum, M. Groenewegen & H. Olofsson, eds.AGB stars are important contributors of processed matter to the ISM. However, the physical and chemical mechanisms involved in its ejection are still poorly known. This process is expected to have remarkable effects in the innermost envelope, where the dust grains are formed, the gas is accelerated, the chemistry is active, and the radiative excitation becomes important. A good tracer of this region in C-rich stars is SiS, an abundant refractory molecule that can display maser lines, very sensitive to changes in the physical conditions. We present high angular resolution interferometer observations (HPBW â‰30.″.25) of the v = 0 J = 14-13 and 15-14 SiS maser lines towards the archetypal AGB star IRC+10216, carried out with CARMA and ALMA to explore the inner 1> region around the central star. We also present an ambitious monitoring of these lines along one single pulsation period carried out with the IRAM 30 m telescope.The research leading to these results has received funding from the European Research
Council under the European Union’s Seventh Framework Programme (FP7/2007-2013)/
ERC grant agreement n◦ 610256: NANOCOSMO
The ultra high resolution XUV spectroheliograph: An attached payload for the Space Station Freedom
The principle goal of the ultra high resolution XUV spectroheliograph (UHRXS) is to improve the ability to identify and understand the fundamental physical processes that shape the structure and dynamics of the solar chromosphere and corona. The ability of the UHRXS imaging telescope and spectrographs to resolve fine scale structures over a broad wavelength (and hence temperature) range is critical to this mission. The scientific objectives and instrumental capabilities of the UHRXS investigation are reviewed before proceeding to a discussion of the expected performance of the UHRXS observatory
Development of optimum clamp combinations for strap-down inertial measuring units with field replaceable sensors
Optimum clamp combinations for strap down inertial measuring units with field replaceable sensor
- …