1,519 research outputs found
Results of phase one of land use information Delphi study
The Land Use Management Information System (LUMIS) is being developed for the city portion of the Santa Monica mountains. LUMIS incorporates data developed from maps and aerial photos as well as traditional land based data associated with routine city and county record keeping activities and traditional census data. To achieve the merging of natural resource data with governmental data LUMIS is being designed in accordance with restrictions associated with two other land use information systems currently being constructed by Los Angeles city staff. The two city systems are LUPAMS (Land Use Planning and Management System) which is based on data recorded by the County Assessor's office for each individual parcel of land in the city, and Geo-BEDS, a geographically based environmental data system
LUMIS Interactive graphics operating instructions and system specifications
The LUMIS program has designed an integrated geographic information system to assist program managers and planning groups in metropolitan regions. Described is the system designed to interactively interrogate a data base, display graphically a portion of the region enclosed in the data base, and perform cross tabulations of variables within each city block, block group, or census tract. The system is designed to interface with U. S. Census DIME file technology, but can accept alternative districting conventions. The system is described on three levels: (1) introduction to the systems's concept and potential applications; (2) the method of operating the system on an interactive terminal; and (3) a detailed system specification for computer facility personnel
The availability of local aerial photography in southern California
Some of the major photography and photogrammetric suppliers and users located in Southern California are listed. Recent trends in aerial photographic coverage of the Los Angeles basin area are also noted, as well as the uses of that imagery
Continuing data analysis of the AS/E grazing incidence X-ray telescope experiment on the OSO-4 satellite
The work to correct and extend the calculation of the theoretical solar X-ray spectrum produced during earlier OSO-4 data analysis is reported along with the work to formulate models of active regions, and compare these models with the experimental values. An atlas of solar X-ray photographs is included, and solar X-ray observations are correlated with the solar wind
An automatic deep learning approach for coronary artery calcium segmentation
Coronary artery calcium (CAC) is a significant marker of atherosclerosis and
cardiovascular events. In this work we present a system for the automatic
quantification of calcium score in ECG-triggered non-contrast enhanced cardiac
computed tomography (CT) images. The proposed system uses a supervised deep
learning algorithm, i.e. convolutional neural network (CNN) for the
segmentation and classification of candidate lesions as coronary or not,
previously extracted in the region of the heart using a cardiac atlas. We
trained our network with 45 CT volumes; 18 volumes were used to validate the
model and 56 to test it. Individual lesions were detected with a sensitivity of
91.24%, a specificity of 95.37% and a positive predicted value (PPV) of 90.5%;
comparing calcium score obtained by the system and calcium score manually
evaluated by an expert operator, a Pearson coefficient of 0.983 was obtained. A
high agreement (Cohen's k = 0.879) between manual and automatic risk prediction
was also observed. These results demonstrated that convolutional neural
networks can be effectively applied for the automatic segmentation and
classification of coronary calcifications
Making the corona and the fast solar wind: a self-consistent simulation for the low-frequency Alfven waves from photosphere to 0.3AU
We show that the coronal heating and the fast solar wind acceleration in the
coronal holes are natural consequence of the footpoint fluctuations of the
magnetic fields at the photosphere, by performing one-dimensional
magnetohydrodynamical simulation with radiative cooling and thermal conduction.
We initially set up a static open flux tube with temperature 10^4K rooted at
the photosphere. We impose transverse photospheric motions corresponding to the
granulations with velocity = 0.7km/s and period between 20 seconds and 30
minutes, which generate outgoing Alfven waves. We self-consistently treat these
waves and the plasma heating. After attenuation in the chromosphere by ~85% of
the initial energy flux, the outgoing Alfven waves enter the corona and
contribute to the heating and acceleration of the plasma mainly by the
nonlinear generation of the compressive waves and shocks. Our result clearly
shows that the initial cool and static atmosphere is naturally heated up to
10^6K and accelerated to 800km/s.Comment: 4 pages, 3 figures, ApJL, 632, L49, corrections of mistypes in
eqs.(3) & (5), Mpeg movie for fig.1 (simulation result) is available at
http://www-tap.scphys.kyoto-u.ac.jp/~stakeru/research/suzuki_200506.mp
Reconnection in a slow Coronal Mass Ejection
This paper aims at studying reconnection occurring in the
aftermath of the 28 May 2004, CME, first imaged by the LASCO (Large Angle and
Spectrometric Coronagraph) C2 at 11:06 UT. The CME was observed in White Light
and UV radiation: images acquired by the LASCO
C2 and C3 coronagraphs and spectra acquired by UVCS (Ultraviolet
Coronagraph Spectrometer) allowed us to identify the level at which
field lines, stretched outwards by the CME ejection, reconnect
below the CME bubble. As the CME propagates outwards, reconnection occurs at
increasingly higher levels. The process goes on at a low pace for several
hours: here we give the profile of the reconnection rate vs. heliocentric
distance over a time interval of ≈14 h after the CME onset,
extending estimates of the reconnection rate to larger distances than previously
inferred by other authors. The reconnection rate appears to decrease with
time/altitude. We also calculate upper and lower limits
to the density in the diffusion region between 4 and 7 <I>R</I><sub>⊙</sub>
and conclude by comparing estimates of the classical and anomalous resistivity
in the diffusion region with the value inferred from the data. The latter
turns out to be ≥5 order of magnitudes larger than predicted by
classical or anomalous theories, pointing to the need of identifying the
process responsible for the observed value
Crossing Over from Attractive to Repulsive Interactions in a Tunneling Bosonic Josephson Junction
We explore the interplay between tunneling and interatomic interactions in
the dynamics of a bosonic Josephson junction. We tune the scattering length of
an atomic K Bose-Einstein condensate confined in a double-well trap to
investigate regimes inaccessible to other superconducting or superfluid
systems. In the limit of small-amplitude oscillations, we study the transition
from Rabi to plasma oscillations by crossing over from attractive to repulsive
interatomic interactions. We observe a critical slowing down in the oscillation
frequency by increasing the strength of an attractive interaction up to the
point of a quantum phase transition. With sufficiently large initial
oscillation amplitude and repulsive interactions the system enters the
macroscopic quantum self-trapping regime, where we observe coherent undamped
oscillations with a self-sustained average imbalance of the relative well
population. The exquisite agreement between theory and experiments enables the
observation of a broad range of many body coherent dynamical regimes driven by
tunable tunneling energy, interactions and external forces, with applications
spanning from atomtronics to quantum metrology.Comment: 10 pages, 8 figures, supplemental materials are include
Lapex: A Phoswich balloon experiment for hard X-ray astronomy
Satellite and balloon observations have shown that several classes of celestial objects are hard ( 15 keV) energy band with a sensitivity of approx 10 mCrab has been performed with the UCSD/MIT instrument (A4) on board the HEAO 1 satellite. About 70 X-ray sources were detected, including galactic and extragalactic objects. Hard X-ray emission has been detected in the Galaxy from X-ray pulsars. Extragalactic sources of hard X-ray emission include clusters of galaxies, QSOs, BL Lac objects, Seyfert galaxies. The essential characteristics of the Large Area Phoswich Experiment (LAPEX) for crowded sky field observations are described. It has: (1) a broad energy band of operation (20-300 keV); (2) a 3 sigma sensitivity of about 1 mCrab in 10,000 s of live observing time; and (3) imaging capabilities with an angular resolution of about 20'
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