89,828 research outputs found
Post Flight Dynamic Analysis Simulation
Digital six-degrees-of-freedom, open loop Saturn 5 first stage flight evaluation simulation program obtains post flight simulation of the launch vehicle using actual flight data as input. Results are compared with measured data. For preflight analysis, the program uses predicted flight data as input
On substitution tilings of the plane with n-fold rotational symmetry
A method is described for constructing, with computer assistance, planar
substitution tilings that have n-fold rotational symmetry. This method uses as
prototiles the set of rhombs with angles that are integer multiples of pi/n,
and includes various special cases that have already been constructed by hand
for low values of n. An example constructed by this method for n = 11 is
exhibited; this is the first substitution tiling with 11-fold symmetry
appearing in the literature.Comment: 17 pages, 10 figure
Piecewise rational quadratic interpolation to monotonic data
An explicit representation of a piecewise rational quadratic function is developed which produces a monotonic interpolant to given monotonic data. The explicit representation means that the piecewise monotonic interpolant is easily constructed and numerical experiments indicate that the method produces visually pleasing curves. Furthermore, the use of the method is justified by an 0(h4) convergence result
A 10-point interpolatory recursive subdivision algorithm for the generation of parametric surfaces
In this paper, an interpolatory subdivision algorithm for surfaces over arbitrary triangulations is introduced and its properties over uniform triangulations studied. The Butterfly Scheme, which is introduced by Dyn, Gregory and Levin is a special case of this algorithm. In our analysis, the matrix approach is employed and the idea of "Cross Difference of Directional Divided Difference" analysis is presented. This method is a generalization of the technique used by Dyn, Gregory and Levin etc. to analyse univariate subdivision algorithms. It is proved that the algorithm produces smooth surfaces provided the shape parameters are kept within an appropriate range
The Cosmic Ray Observatory Project: A Statewide Outreach and Education Experiment in Nebraska
The Cosmic Ray Observatory Project (CROP) is a statewide education and
research experiment involving Nebraska high school students, teachers and
university undergraduates in the study of extensive cosmic-ray air showers. A
network of high school teams construct, install, and operate school-based
detectors in coordination with University of Nebraska physics professors and
graduate students. The detector system at each school is an array of
scintillation counters recycled from the Chicago Air Shower Array in
weather-proof enclosures on the school roof, with a GPS receiver providing a
time stamp for cosmic-ray events. The detectors are connected to triggering
electronics and a data-acquisition PC inside the building. Students share data
via the Internet to search for time coincidences with other sites. Funded by
the National Science Foundation, CROP has enlisted 29 schools with the aim of
expanding to the 314 high schools in the state over several years. This report
highlights both the scientific and professional development achievements of the
project to date.Comment: 4 pages, 4 figures, submitted to the 2007 International Cosmic Ray
Conference (ICRC2007), Merida, Mexico, July 200
The Future of X-ray Time Domain Surveys
Modern X-ray observatories yield unique insight into the astrophysical time
domain. Each X-ray photon can be assigned an arrival time, an energy and a sky
position, yielding sensitive, energy-dependent light curves and enabling
time-resolved spectra down to millisecond time-scales. Combining those with
multiple views of the same patch of sky (e.g., in the Chandra and XMM-Newton
deep fields) so as to extend variability studies over longer baselines, the
spectral timing capacity of X-ray observatories then stretch over 10 orders of
magnitude at spatial resolutions of arcseconds, and 13 orders of magnitude at
spatial resolutions of a degree. A wealth of high-energy time-domain data
already exists, and indicates variability on timescales ranging from
microseconds to years in a wide variety of objects, including numerous classes
of AGN, high-energy phenomena at the Galactic centre, Galactic and
extra-Galactic X-ray binaries, supernovae, gamma-ray bursts, stellar flares,
tidal disruption flares, and as-yet unknown X-ray variables. This workshop
explored the potential of strategic X-ray surveys to probe a broad range of
astrophysical sources and phenomena. Here we present the highlights, with an
emphasis on the science topics and mission designs that will drive future
discovery in the X-ray time domain.Comment: 8 pages, 1 figure, Conference proceedings for IAU Symposium 285, "New
Horizons in Time Domain Astronomy," Oxford, UK, Sep 19-23, 2011. To be
published by IA
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