2,158 research outputs found
Energy spectra of two interacting fermions with spin-orbit coupling in a harmonic trap
We explore the two-body spectra of spin- fermions in isotropic harmonic
traps with external spin-orbit potentials and short range two-body
interactions. Using a truncated basis of total angular momentum eigenstates,
non-perturbative results are presented for experimentally realistic forms of
the spin-orbit coupling: a pure Rashba coupling, Rashba and Dresselhaus
couplings in equal parts, and a Weyl-type coupling. The technique is easily
adapted to bosonic systems and other forms of spin-orbit coupling.Comment: 12 pages, 9 figure
Optical processing for landmark identification
A study of optical pattern recognition techniques, available components and airborne optical systems for use in landmark identification was conducted. A data base of imagery exhibiting multisensor, seasonal, snow and fog cover, exposure, and other differences was assembled. These were successfully processed in a scaling optical correlator using weighted matched spatial filter synthesis. Distinctive data classes were defined and a description of the data (with considerable input information and content information) emerged from this study. It has considerable merit with regard to the preprocessing needed and the image difference categories advanced. A optical pattern recognition airborne applications was developed, assembled and demontrated. It employed a laser diode light source and holographic optical elements in a new lensless matched spatial filter architecture with greatly reduced size and weight, as well as component positioning toleranced
Water Ice in 2060 Chiron and its Implications for Centaurs and Kuiper Belt Objects
We report the detection of water ice in the Centaur 2060 Chiron, based on
near-infrared spectra (1.0 - 2.5 micron) taken with the 3.8-meter United
Kingdom Infrared Telescope (UKIRT) and the 10-meter Keck Telescope. The
appearance of this ice is correlated with the recent decline in Chiron's
cometary activity: the decrease in the coma cross-section allows previously
hidden solid-state surface features to be seen. We predict that water ice is
ubiquitous among Centaurs and Kuiper Belt objects, but its surface coverage
varies from object to object, and thus determines its detectability and the
occurrence of cometary activity.Comment: 18 pages, 3 figures, accepted by ApJ Letter
Population of the Scattered Kuiper Belt
We present the discovery of three new Scattered Kuiper Belt Objects (SKBOs)
from a wide-field survey of the ecliptic. This continuing survey has to date
covered 20.2 square degrees to a limiting red magnitude of 23.6. We combine the
data from this new survey with an existing survey conducted at the University
of Hawaii 2.2m telescope to constrain the number and mass of the SKBOs. The
SKBOs are characterized by large eccentricities, perihelia near 35 AU, and
semi-major axes > 50 AU. Using a maximum-likelihood model, we estimate the
total number of SKBOs larger than 100 km in diameter to be N = 3.1 (+1.9/-1.3)
x 10^4 (1 sigma) and the total mass of SKBOs to be about 0.05 Earth masses,
demonstrating that the SKBOs are similar in number and mass to the Kuiper Belt
inside 50 AU.Comment: 15 pages, 3 figure
OTSS: Oulu traffic simulation system
Abstract. This thesis presents the design and the implementation of Oulu Traffic Simulation System (OTSS), a traffic simulation system for the City of Oulu, Finland. Following agent-based approach, the simulation generates artificial agents that represent the population synthesis of the City of Oulu. Data from several sources, including official statistics, government-organized open data and crowdsourced information were collected and used as input for the simulation. Two traffic demand models are presented in this thesis: (1) the random model which generates traffic trips as random, discrete events; and (2) the activity-based model which defines traffic trips as sequential events in the agents’ day plan. The software development of the system follows the spiral model of software development and enhancement. During the implementation, several development cycles were conducted before the UML software design. The system was executed on two computation systems to test its real-time performance. To evaluate the traffic models, data extracted from the simulation was compared with aggregated survey data from Finnish Transport Agency and traffic count stations around the city. The results showed that a typical server is capable of running the simulation, and even though there were differences in the duration and distance of individual trips, the simulation reflects real-life traffic count significantly well
Integrated Advanced Microwave Sounding Unit-A (AMSU-A): METSAT A2 Signal Processor Engineering Test Report (P/N: 1331120-2, S/N: F02)
This is the METSAT A2 Signal Processor Engineering Test Report (P/N 1331120-2, S/N F02 for the Integrated Advanced Microwave Sounding Unit-A (AMSL)-A)
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