Display/control requirements for automated VTOL aircraft

A systematic design methodology for pilot displays in advanced commercial VTOL aircraft was developed and refined. The analyst is provided with a step-by-step procedure for conducting conceptual display/control configurations evaluations for simultaneous monitoring and control pilot tasks. The approach consists of three phases: formulation of information requirements, configuration evaluation, and system selection. Both the monitoring and control performance models are based upon the optimal control model of the human operator. Extensions to the conventional optimal control model required in the display design methodology include explicit optimization of control/monitoring attention; simultaneous monitoring and control performance predictions; and indifference threshold effects. The methodology was applied to NASA's experimental CH-47 helicopter in support of the VALT program. The CH-47 application examined the system performance of six flight conditions. Four candidate configurations are suggested for evaluation in pilot-in-the-loop simulations and eventual flight tests

Display/control requirements for VTOL aircraft

Quantative metrics were determined for system control performance, workload for control, monitoring performance, and workload for monitoring. Pilot tasks were allocated for navigation and guidance of automated commercial V/STOL aircraft in all weather conditions using an optimal control model of the human operator to determine display elements and design

A new approach to aerial combat games

Application of differential game theory to aerial combat game

Microscopic mechanism for mechanical polishing of diamond (110) surfaces

Mechanically induced degradation of diamond, as occurs during polishing, is studied using total--energy pseudopotential calculations. The strong asymmetry in the rate of polishing between different directions on the diamond (110) surface is explained in terms of an atomistic mechanism for nano--groove formation. The post--polishing surface morphology and the nature of the polishing residue predicted by this mechanism are consistent with experimental evidence.Comment: 4 pages, 5 figure

Hot DAVs : a probable new class of pulsating white dwarf stars

We have discovered a pulsating DA white dwarf at the lower end of the temperature range 45 000–30 000 K where a few helium atmosphere white dwarfs are known. There are now three such pulsators known, suggesting that a new class of theoretically predicted pulsating white dwarf stars exists. We name them the hot DAV stars. From high-speed photometric observations with the ULTRACAM photometer on the 4.2-m William Herschel Telescope, we show that the hydrogen atmosphere white dwarf star WD1017−138 pulsates in at least one mode with a frequency of 1.62 mHz (a period of 624 s). The amplitude of that mode was near 1 mmag at a 10σ confidence level on one night of observation and an 8.4σ confidence level on a second night. The combined data have a confidence level of 11.8σ. This supports the two other detections of hot DAV stars previously reported. From three Very Large Telescope Ultraviolet and Visual Echelle Spectrograph spectra we confirm also that WD1017−138 is a hydrogen atmosphere white dwarf with no trace of helium or metals with Teff = 32 600 K, log g = 7.8 (cgs) and M = 0.55 M⊙. The existence of pulsations in these DA white dwarfs at the cool edge of the 45 000–30 000 K temperature range supports the thin hydrogen layer model for the deficit of helium atmosphere white dwarfs in this range. DA white dwarfs with thick hydrogen layers do not have the superadiabatic, chemically inhomogeneous (μ-gradient) zone that drives pulsation in this temperature range. The potential for higher amplitude hot DAV stars exists; their discovery would open the possibility of a direct test of the explanation for the deficit of helium atmosphere white dwarfs at these temperatures by asteroseismic probing of the atmospheric layers of the hot DAV stars. A search for pulsation in a further 22 candidates with ULTRACAM on the European Southern Observatory New Technology Telescope gave null results for pulsation at precisions in the range 0.5–3 mmag, suggesting that the pulsation amplitudes in such stars are relatively low, hence near the detection limit with the ground-based telescopes used in the surve

Barriers to adherence to COPD guidelines among primary care providers

Background: Despite efforts to disseminate guidelines for managing chronic obstructive pulmonary disease (COPD), adherence to COPD guidelines remains suboptimal. Barriers to adhering to guidelines remain poorly understood. Methods: Clinicians from two general medicine practices in New York City were surveyed to identify barriers to implementing seven recommendations from the Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines. Barriers assessed included unfamiliarity, disagreement, low perceived benefit, low self-efficacy, and time constraints. Exact conditional regression was used to identify barriers independently associated with non-adherence. Results: The survey was completed by 154 clinicians. Adherence was lowest to referring patients with a forced expiratory volume in 1 s (FEV_1) <80% predicted to pulmonary rehabilitation (5%); using FEV_1 to guide management (12%); and ordering pulmonary function tests (PFTs) in smokers (17%). Adherence was intermediate to prescribing inhaled corticosteroids when FEV1 <50% predicted (41%) and long-acting bronchodilators when FEV1 <80% predicted (54%). Adherence was highest for influenza vaccination (90%) and smoking cessation counseling (91%). In unadjusted analyses, low familiarity with the guidelines, low self-efficacy, and time constraints were significantly associated with non-adherence to ≥2 recommendations. In adjusted analyses, low self-efficacy was associated with less adherence to prescribing inhaled corticosteroids (OR: 0.28; 95% CI: 0.10, 0.74) and time constraints were associated with less adherence to ordering PFTs in smokers (OR: 0.31; 95% CI: 0.08, 0.99). Conclusions: Poor familiarity with recommendations, low self-efficacy, and time constraints are important barriers to adherence to COPD guidelines. This information can be used to develop tailored interventions to improve guideline adherence

An ultra-cool white dwarf serendipitously found with COMBO-17

We report the discovery of an ultra-cool white dwarf in the COMBO-17 survey. So far, only seven objects have been discovered in this rare category of white dwarfs, which are characterized by strong flux depression in the far-red and near-infrared part of the spectrum, presumably due to collisionally induced absorption (CIA). The new object COMBO-17 J114356.08-0144032 has very similar colours to LHS 3250, which was the first of its kind to be recognized. However, at R=21.5 it is the faintest and possibly most distant such object discovered to date. It is the only such object in COMBO-17 at R<23; due to the small sky coverage of 0.78 square degree this chance discovery can not provide any constraints on the abundance of faint ultra-cool white dwarfs. We speculate on the basis of the proper motion that this new object is probably a member of the Galactic (thin) disk.Comment: accepted for publication by A&A Letters, 4 pages in print forma