6,442 research outputs found
Resource Allocation Planning Helper (RALPH): Lessons learned
The current task of Resource Allocation Process includes the planning and apportionment of JPL's Ground Data System composed of the Deep Space Network and Mission Control and Computing Center facilities. The addition of the data driven, rule based planning system, RALPH, has expanded the planning horizon from 8 weeks to 10 years and has resulted in large labor savings. Use of the system has also resulted in important improvements in science return through enhanced resource utilization. In addition, RALPH has been instrumental in supporting rapid turn around for an increased volume of special what if studies. The status of RALPH is briefly reviewed and important lessons learned from the creation of an highly functional design team are focused on through an evolutionary design and implementation period in which an AI shell was selected, prototyped, and ultimately abandoned, and through the fundamental changes to the very process that spawned the tool kit. Principal topics include proper integration of software tools within the planning environment, transition from prototype to delivered to delivered software, changes in the planning methodology as a result of evolving software capabilities and creation of the ability to develop and process generic requirements to allow planning flexibility
Simulation of Near Horizontal Muons and Muon Bundles for the HAWC Observatory with CORSIKA
The HAWC (High Altitude Water Cerenkov) gamma ray observatory observes muons
with nearly-horizontal trajectories corresponding to zenith angles greater than
. HAWC is located at an altitude of 4100 meters a.s.l. (70 deg.
atmospheric depth of 2400 g/cm) on the extinct volcano, Sierra Negra in
Mexico. In this poster, we summarize the CORSIKA and GEANT4 as well as
toy-model based simulations performed to determine the effective area of HAWC
to muons from high zenith angle cosmic ray primaries. We are developing an
updated GEANT4 based detector response simulation that includes a model of the
volcanoes that are located near HAWC. These simulations are investigating the
capability to use muon multiplicity and rates to differentiate between the
primary particle composition (proton or iron) and measure the primary energy.Comment: Presented at the 35th International Cosmic Ray Conference (ICRC2017),
Bexco, Busan, Korea. See arXiv:1708.02572 for all HAWC contribution
Detection of Near Horizontal Muons with the HAWC Observatory
The HAWC (High Altitude Water Cherenkov) gamma ray observatory is able to
observe muons with nearly horizontal trajectories. HAWC is located at an
altitude of 4100 meters a.s.l. on the Sierra Negra volcano in Mexico. The HAWC
detector is composed of 300 water tanks, each 7.3 m in diameter and 4.5 m tall,
densely packed over a physical area of 22,000 m. Previous and current
experiments have observed high zenith angle (near horizontal) muons at or near
sea level. HAWC operates as a hodoscope able to observe multi-TeV muons at
zenith angles greater than 75 degrees. This is the first experiment to measure
near horizontal muons at high altitude and with large ( 10 m) separations
for multiple muons. These muons are distinguishable from extensive air showers
by observing near horizontal particles propagating with the speed of light. The
proximity of Sierra Negra and Pico de Orizaba volcanoes provides an additional
measurement of muons with rock overburdens of several km water equivalent. We
will present the angular distribution and rate at which HAWC observes these
muon eventsComment: Presented at the 35th International Cosmic Ray Conference (ICRC2017),
Bexco, Busan, Korea. See arXiv:1708.02572 for all HAWC contribution
Contextual planning for NASA - A second workbook of alternative future environments for mission analysis, volume 1 Interim report
Contextural planning for selecting alternate NASA program
Noiseless Quantum Circuits for the Peres Separability Criterion
In this Letter we give a method for constructing sets of simple circuits that
can determine the spectrum of a partially transposed density matrix, without
requiring either a tomographically complete POVM or the addition of noise to
make the spectrum non-negative. These circuits depend only on the dimension of
the Hilbert space and are otherwise independent of the state.Comment: 4 pages RevTeX, 7 figures encapsulated postscript. v5: title changed
slightly, more-or-less equivalent to the published versio
Study of an engine flow diverter system for a large scale ejector powered aircraft model
Requirements were established for a conceptual design study to analyze and design an engine flow diverter system and to include accommodations for an ejector system in an existing 3/4 scale fighter model equipped with YJ-79 engines. Model constraints were identified and cost-effective limited modification was proposed to accept the ejectors, ducting and flow diverter valves. Complete system performance was calculated and a versatile computer program capable of analyzing any ejector system was developed
Radiative Decays X(3872) -> psi(2S)+gamma and psi(4040) -> X(3872)+gamma in Effective Field Theory
Heavy hadron chiral perturbation theory (HHchiPT) and XEFT are applied to the
decays X(3872) -> psi(2S) + gamma and psi(4040) -> X(3872) + gamma under the
assumption that the X(3872) is a molecular bound state of neutral charm mesons.
In these decays the emitted photon energies are 181 MeV and 165 MeV,
respectively, so HHchiPT can be used to calculate the underlying D^0
bar{D}^{0*}+ bar{D}^0 D^{0*} -> psi(2S) + gamma or psi(4040) -> (D^0
bar{D}^{0*}+ bar{D}^0 D^{0*}) + gamma transition. These amplitudes are matched
onto XEFT to obtain decay rates. The decays receive contributions from both
long distance and short distance processes. We study the polarization of the
psi(2S) in the decay X(3872) -> psi(2S) + gamma and the angular distribution of
X(3872) in the decay psi(4040) -> X(3872) + gamma and find they can be used to
differentiate between different decay mechanisms as well as discriminate
between 2^{-+} and 1^{++} quantum number assignments of the X(3872).Comment: 13 pages, 4 figure
Graphics calculators and the school mathematics curriculum: Perspectives and issues from three countries
Over the past two decades, graphics calculators have been prominent in many discussions of technology in mathematics education. This paper describes how they have become part of teaching, learning and assessment in school mathematics in each of three different countries: Australia, Singapore and the United States of America, as well as directions for future use. Critical issues associated with effective implementation of graphics calculators into the school mathematics curriculum are highlighted, including the nature of school mathematics, examination practices, Computer Algebra Systems, the support of teachers and students, curriculum change and development, the focus on learning, dealing with inherent limitations of graphics calculators, school and university differences, future technologies
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