29,440 research outputs found
Combined monitoring, decision and control model for the human operator in a command and control desk
A report is given on the ongoing efforts to mode the human operator in the context of the task during the enroute/return phases in the ground based control of multiple flights of remotely piloted vehicles (RPV). The approach employed here uses models that have their analytical bases in control theory and in statistical estimation and decision theory. In particular, it draws heavily on the modes and the concepts of the optimal control model (OCM) of the human operator. The OCM is being extended into a combined monitoring, decision, and control model (DEMON) of the human operator by infusing decision theoretic notions that make it suitable for application to problems in which human control actions are infrequent and in which monitoring and decision-making are the operator's main activities. Some results obtained with a specialized version of DEMON for the RPV control problem are included
On the internal target model in a tracking task
An optimal control model for predicting operator's dynamic responses and errors in target tracking ability is summarized. The model, which predicts asymmetry in the tracking data, is dependent on target maneuvers and trajectories. Gunners perception, decision making, control, and estimate of target positions and velocity related to crossover intervals are discussed. The model provides estimates for means, standard deviations, and variances for variables investigated and for operator estimates of future target positions and velocities
An analysis of the application of AI to the development of intelligent aids for flight crew tasks
This report presents the results of a study aimed at developing a basis for applying artificial intelligence to the flight deck environment of commercial transport aircraft. In particular, the study was comprised of four tasks: (1) analysis of flight crew tasks, (2) survey of the state-of-the-art of relevant artificial intelligence areas, (3) identification of human factors issues relevant to intelligent cockpit aids, and (4) identification of artificial intelligence areas requiring further research
General Relativistic Radiative Transfer
We present a general method to calculate radiative transfer including
scattering in the continuum as well as in lines in spherically symmetric
systems that are influenced by the effects of general relativity (GR). We
utilize a comoving wavelength ansatz that allows to resolve spectral lines
throughout the atmosphere. The used numerical solution is an operator splitting
(OS) technique that uses a characteristic formal solution. The bending of
photon paths and the wavelength shifts due to the effects of GR are fully taken
into account, as is the treatment of image generation in a curved spacetime. We
describe the algorithm we use and demonstrate the effects of GR on the
radiative transport of a two level atom line in a neutron star like atmosphere
for various combinations of continuous and line scattering coefficients. In
addition, we present grey continuum models and discuss the effects of different
scattering albedos on the emergent spectra and the determination of effective
temperatures and radii of neutron star atmospheres
Type II Supernovae: Model Light Curves and Standard Candle Relationships
A survey of Type II supernovae explosion models has been carried out to
determine how their light curves and spectra vary with their mass, metallicity,
and explosion energy. The presupernova models are taken from a recent survey of
massive stellar evolution at solar metallicity supplemented by new calculations
at subsolar metallicity. Explosions are simulated by the motion of a piston
near the edge of the iron core and the resulting light curves and spectra are
calculated using full multi-wavelength radiation transport. Formulae are
developed that describe approximately how the model observables (light curve
luminosity and duration) scale with the progenitor mass, explosion energy, and
radioactive nucleosynthesis. Comparison with observational data shows that the
explosion energy of typical supernovae (as measured by kinetic energy at
infinity) varies by nearly an order of magnitude -- from 0.5 to 4.0 x 10^51
ergs, with a typical value of ~0.9 x 10^51 ergs. Despite the large variation,
the models exhibit a tight relationship between luminosity and expansion
velocity, similar to that previously employed empirically to make SNe IIP
standardized candles. This relation is explained by the simple behavior of
hydrogen recombination in the supernova envelope, but we find a sensitivity to
progenitor metallicity and mass that could lead to systematic errors.
Additional correlations between light curve luminosity, duration, and color
might enable the use of SNe IIP to obtain distances accurate to ~20% using only
photometric data.Comment: 12 pages, ApJ in pres
Analytic evaluation of display requirements for approach to landing
A pilot-vehicle-display model is used to study information and display requirements and the effects on system performance and reliability of pilot-induced randomness, wind gusts, configurational changes, etc. A brief description of a control theoretic systems model is given and its use and validity are demonstrated by applying it in a piloted approach to landing situation. The analysis procedure assumes that the vehicle dynamics are represented by linearized equations of motion
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Endolithic colonization of fluid inclusion trails in mineral grains
Many scenarios for the colonization of planetary surfaces by microbial life involve endoliths. This study records microbial mass along fluid inclusion trails (healed microfractures) in quartz grains
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Visual attention in autism families: ‘unaffected’ sibs share atypical frontal activation
Background: In addition to their more clinically evident abnormalities of social cognition, people with autism spectrum conditions (ASC) manifest perturbations of attention and sensory perception which may offer insights into the underlying neural abnormalities. Similar autistic traits in ASC relatives without a diagnosis suggest a continuity between clinically affected and unaffected family members
Sex differences in the brain: implications for explaining autism
‘Empathizing’ is the capacity to predict and to respond to the behavior of agents (usually people) by inferring their mental states and responding to these with an appropriate emotion. ‘Systemizing’ is the capacity to predict and to respond to the behavior of non-agentive, deterministic systems, by analyzing input-operation-output relations and inferring the rules that govern such systems. At a population level, females are stronger empathizers and males stronger systemizers. The ‘extreme male brain’ theory posits that autism represents an extreme of the male pattern (impaired empathizing and enhanced systemizing). Here we suggest that specific aspects of autistic neuropathology may also be extremes of typical male neuroanatomy
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