11 research outputs found
A Linear Combination of Heuristics Approach to Spatial Sampling Hyperspectral Data for Target Tracking
Persistent surveillance of the battlespace results in better battlespace awareness which aids in obtaining air superiority, winning battles, and saving friendly lives. Although hyperspectral imagery (HSI) data has proven useful for discriminating targets, it presents many challenges as a useful tool in persistent surveillance. A new sensor under development has the potential of overcoming these challenges and transforming our persistent surveillance capability by providing HSI data for a limited number of pixels and grayscale video for the remainder. The challenge of exploiting this new sensor is determining where the HSI data in the sensor\u27s field of view will be the most useful. The approach taken is to use a utility function with components of equal dispersion, periodic poling, missed measurements, and predictive probability of association error (PPAE). The relative importance or optimal weighting of the different types of TOI is accomplished by a genetic algorithm using a multi-objective problem formulation. Experiments show using the utility function with equal weighting results in superior target tracking compared to any individual component by itself, and the equal weighting in close to the optimal solution. The new sensor is successfully exploited resulting in improved persistent surveillance
Traveling Salesman Problem for Surveillance Mission Using Particle Swarm Optimization
The surveillance mission requires aircraft to fly from a starting point through defended terrain to targets and return to a safe destination (usually the starting point). The process of selecting such a flight path is known as the Mission Route Planning (MRP) Problem and is a three-dimensional, multi-criteria (fuel expenditure, time required, risk taken, priority targeting, goals met, etc.) path search. Planning aircraft routes involves an elaborate search through numerous possibilities, which can severely task the resources of the system being used to compute the routes. Operational systems can take up to a day to arrive at a solution due to the combinatoric nature of the problem. This delay is not acceptable because timeliness of obtaining surveillance information is critical in many surveillance missions. Also, the information that the software uses to solve the MRP may become invalid during computation. An effective and efficient way of solving the MRP with multiple aircraft and multiple targets is desired. One approach to finding solutions is to simplify and view the problem as a two-dimensional, minimum path problem. This approach also minimizes fuel expenditure, time required, and even risk taken. The simplified problem is then the Traveling Salesman Problem (TSP)
Was 49b: An Overmassive AGN in a Merging Dwarf Galaxy?
We present a combined morphological and X-ray analysis of Was 49, an
isolated, dual AGN system notable for the presence of a dominant AGN Was 49b in
the disk of the primary galaxy Was 49a, at a projected radial distance of 8 kpc
from the nucleus. Using X-ray data from Chandra, NuSTAR, and Swift, we find
that this AGN has a bolometric luminosity of L_bol ~ 2 x 10^45 erg/s, with a
black hole mass of M_BH=1.3^{+2.9}_{-0.9} x 10^8 M_Sol. Despite its large mass,
our analysis of optical data from the Discovery Channel Telescope shows that
the supermassive black hole is hosted by a stellar counterpart with a mass of
only 5.6^{+4.9}_{-2.6} x 10^9 M_Sol, making the SMBH potentially larger than
expected from SMBH-galaxy scaling relations, and the stellar counterpart
exhibits a morphology that is consistent with dwarf elliptical galaxies. Our
analysis of the system in the r and K bands indicates that Was 49 is a minor
merger, with a mass ratio of Was 49a to Was 49b between 1:7 and 1:15. This is
in contrast with findings that the most luminous merger-triggered AGNs are
found in major mergers, and that minor mergers predominantly enhance AGN
activity in the primary galaxy.Comment: 11 pages, 6 figures, accepted for publication in Ap
The G0 Experiment: Apparatus for Parity-Violating Electron Scattering Measurements at Forward and Backward Angles
In the G0 experiment, performed at Jefferson Lab, the parity-violating
elastic scattering of electrons from protons and quasi-elastic scattering from
deuterons is measured in order to determine the neutral weak currents of the
nucleon. Asymmetries as small as 1 part per million in the scattering of a
polarized electron beam are determined using a dedicated apparatus. It consists
of specialized beam-monitoring and control systems, a cryogenic hydrogen (or
deuterium) target, and a superconducting, toroidal magnetic spectrometer
equipped with plastic scintillation and aerogel Cerenkov detectors, as well as
fast readout electronics for the measurement of individual events. The overall
design and performance of this experimental system is discussed.Comment: Submitted to Nuclear Instruments and Method
VaDAR: Varstrometry for Dual AGN using Radio interferometry
Binary and dual active galactic nuclei (AGN) are an important observational
tool for studying the formation and dynamical evolution of galaxies and
supermassive black holes (SMBHs). An entirely new method for identifying
possible AGN pairs makes use of the exquisite positional accuracy of Gaia to
detect astrometrically-variable quasars, in tandem with the high spatial
resolution of the Karl G. Jansky Very Large Array (VLA). We present a new pilot
study of radio observations of 18 quasars (0.8 < z < 2.9), selected from the
SDSS DR16Q and matched with the Gaia DR3. All 18 targets are identified by
their excess astrometric noise in Gaia. We targeted these 18 quasars with the
VLA at 2-4 GHz (S-band) and 8-12 GHz (X-band), providing resolutions of 0.65"
and 0.2", respectively, in order to constrain the origin of this variability.
We combine these data with ancillary radio survey data and perform radio
spectral modeling. The new observations are used to constrain the driver of the
excess astrometric noise. We find that ~39% of the target sample is likely to
be either candidate dual AGN or gravitationally lensed quasars. Ultimately, we
use this new strategy to help identify and understand this sample of
astrometrically-variable quasars, demonstrate the potential of this method for
systematically identifying kpc-scale dual quasars.Comment: 38 pages, 21 figures, 8 tables, submitted to ApJ, comments welcome
A Flexible Analysis Tool for the Quantitative Acoustic Assessment of Infant Cry
Lincoln Memorial (by Henry Bacon, 1922), distant view from the base of the Washington Monumen