5,395 research outputs found
A human factors approach to range scheduling for satellite control
Range scheduling for satellite control presents a classical problem: supervisory control of a large-scale dynamic system, with unwieldy amounts of interrelated data used as inputs to the decision process. Increased automation of the task, with the appropriate human-computer interface, is highly desirable. The development and user evaluation of a semi-automated network range scheduling system is described. The system incorporates a synergistic human-computer interface consisting of a large screen color display, voice input/output, a 'sonic pen' pointing device, a touchscreen color CRT, and a standard keyboard. From a human factors standpoint, this development represents the first major improvement in almost 30 years to the satellite control network scheduling task
Spillovers, Foreign Investment, and Export Behavior
Case studies of export behavior suggest that firms who penetrate foreign markets reduce entry costs for other potential exporters, either through learning by doing or through establishing buyer- supplier linkages. We pursue the idea that spillovers associated with one firm's export activity reduce the cost of foreign market access for other firms. We identify two potential sources of spillovers: export activity in general and the specific activities of multinational enterprises. We use a simple model of export behavior to derive a logit specification for the probability a firm exports. Using panel data on Mexican manufacturing plants, we find evidence consistent with spillovers from the export activity of multinational enterprises but not with general export activity.
High Resolution Millimeter-Wave Mapping of Linearly Polarized Dust Emission: Magnetic Field Structure in Orion
We present 1.3 and 3.3 mm polarization maps of Orion-KL obtained with the
BIMA array at approximately 4 arcsec resolution. Thermal emission from
magnetically aligned dust grains produces the polarization. Along the Orion
``ridge'' the polarization position angle varies smoothly from about 10 degrees
to 40 degrees, in agreement with previous lower resolution maps. In a small
region south of the Orion ``hot core,'' however, the position angle changes by
90 degrees. This abrupt change in polarization direction is not necessarily the
signpost of a twisted magnetic field. Rather, in this localized region
processes other than the usual Davis-Greenstein mechanism might align the dust
grains with their long axes parallel with the field, orthogonal to their normal
orientation.Comment: AAS preprint:14 pages, 2 figures (3mm.eps and 1mm.eps); requires
aaspp4.sty To be published in Astrophysical Journal Letter
Paper Session II-C - Astro: A Computer-Aided Scheduling Tool for Operational Satellite Control
Range scheduling for satellite control presents a classical problem of a data intensive task with a very small allowance for human error. On any given day, interrelated information depicting 600-1000 entries of satellite visibilities and scheduled range support must be interpreted and used to make decisions that can be critical to the survival of valuable orbital assets. Given an environment which must account for unexpected equipment outages and satellite anomalies, the scheduling task can exceed acceptable workload levels. Thus, range scheduling for satellite control can benefit greatly from computer assistance and a human factors approach to the task. This paper describes the development, user evaluation, and operational activation of a semi-automated network range scheduling system incorporating a synergistic humancomputer interface consisting of a large screen color display, voice input/output, a sonic penn pointing device, a touchscreen color CRT, and a standard keyboard. The development and operational use of ASTRO represent the first major improvement in almost 30 years to the range scheduling task
The NCBO OBOF to OWL Mapping
Two of the most significant formats for biomedical ontologies are the Open Biomedical Ontologies Format (OBOF) and the Web Ontology Language (OWL). To make it possible to translate ontologies between these two representation formats, the National Center for Biomedical Ontology (NCBO) has developed a mapping between the OBOF and OWL formats as well as inter-conversion software. The goal was to allow the sharing of tools, ontologies, and associated data between the OBOF and Semantic Web communities.

OBOF does not have a formal grammar, so the NCBO had to capture its intended semantics to map it to OWL.

This official NCBO mapping was used to make all OBO Foundry ontologies available in OWL. 

Availability: This mapping functionality can be embedded into OBO-Edit and Protégé-OWL ontology editors. This software is available at: http://bioontology.org/wiki/index.php/OboInOwl:Main_Pag
Polarization of Thermal Emission from Aligned Dust Grains Under an Anisotropic Radiation Field
If aspherical dust grains are immersed in an anisotropic radiation field,
their temperature depends on the cross-sections projected in the direction of
the anisotropy.It was shown that the temperature difference produces polarized
thermal emission even without alignment, if the observer looks at the grains
from a direction different from the anisotropic radiation. When the dust grains
are aligned, the anisotropy in the radiation makes various effects on the
polarization of the thermal emission, depending on the relative angle between
the anisotropy and alignment directions. If the both directions are parallel,
the anisotropy produces a steep increase in the polarization degree at short
wavelengths. If they are perpendicular, the polarization reversal occurs at a
wavelength shorter than the emission peak. The effect of the anisotropic
radiation will make a change of more than a few % in the polarization degree
for short wavelengths and the effect must be taken into account in the
interpretation of the polarization in the thermal emission. The anisotropy in
the radiation field produces a strong spectral dependence of the polarization
degree and position angle, which is not seen under isotropic radiation. The
dependence changes with the grain shape to a detectable level and thus it will
provide a new tool to investigate the shape of dust grains. This paper presents
examples of numerical calculations of the effects and demonstrates the
importance of anisotropic radiation field on the polarized thermal emission.Comment: 13pages, 7figure
Lagrangian Framework for Systems Composed of High-Loss and Lossless Components
Using a Lagrangian mechanics approach, we construct a framework to study the
dissipative properties of systems composed of two components one of which is
highly lossy and the other is lossless. We have shown in our previous work that
for such a composite system the modes split into two distinct classes,
high-loss and low-loss, according to their dissipative behavior. A principal
result of this paper is that for any such dissipative Lagrangian system, with
losses accounted by a Rayleigh dissipative function, a rather universal
phenomenon occurs, namely, selective overdamping: The high-loss modes are all
overdamped, i.e., non-oscillatory, as are an equal number of low-loss modes,
but the rest of the low-loss modes remain oscillatory each with an extremely
high quality factor that actually increases as the loss of the lossy component
increases. We prove this result using a new time dynamical characterization of
overdamping in terms of a virial theorem for dissipative systems and the
breaking of an equipartition of energy.Comment: 53 pages, 1 figure; Revision of our original manuscript to
incorporate suggestions from refere
Effects of Mismatch Strain and Substrate Surface Corrugation on Morphology of Supported Monolayer Graphene
Graphene monolayers supported on oxide substrates have been demonstrated with
superior charge mobility and thermal transport for potential device
applications. Morphological corrugation can strongly influence the transport
properties of the supported graphene. In this paper, we theoretically analyze
the morphological stability of a graphene monolayer on an oxide substrate,
subject to van der Waals interactions and in-plane mismatch strains. First, we
define the equilibrium separation and the interfacial adhesion energy as the
two key parameters that characterize the van der Waals interaction between a
flat monolayer and a flat substrate surface. By a perturbation analysis, a
critical compressive mismatch strain is predicted, beyond which the graphene
monolayer undergoes strain-induced instability, forming corrugations with
increasing amplitude and decreasing wavelength on a perfectly flat surface.
When the substrate surface is not perfectly flat, the morphology of graphene
depends on both the amplitude and the wavelength of the surface corrugation. A
transition from conformal (corrugated) to non-conformal (flat) morphology is
predicted. The effects of substrate surface corrugation on the equilibrium mean
thickness of the supported graphene and the interfacial adhesion energy are
analyzed. Furthermore, by considering both the substrate surface corrugation
and the mismatch strain, it is found that, while a tensile mismatch strain
reduces the corrugation amplitude of graphene, a corrugated substrate surface
promotes strain-induced instability under a compressive strain. These
theoretical results suggest possible means to control the morphology of
graphene monolayer on oxide substrates by surface patterning and strain
engineering.Comment: 25 pages, 9 figures, submitted for review on March 3, 201
Identities for hyperelliptic P-functions of genus one, two and three in covariant form
We give a covariant treatment of the quadratic differential identities
satisfied by the P-functions on the Jacobian of smooth hyperelliptic curves of
genera 1, 2 and 3
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