18 research outputs found
Telerobotic hand controller study of force reflection with position control mode
To gain further information about the effectiveness of kinesthetic force feedback or force reflection in position control mode for a telerobot, two Space Station related tasks were performed by eight subjects with and without the use of force reflection. Both time and subjective responses were measured. No differences due to force were found, however, other differences were found, e.g., gender. Comparisons of these results with other studies are discussed
The Hydrogen-Poor Superluminous Supernovae from the Zwicky Transient Facility Phase-I Survey: I. Light Curves and Measurements
During the Zwicky Transient Facility (ZTF) Phase-I operation, 78
hydrogen-poor superluminous supernovae (SLSNe-I) were discovered in less than
three years, making up the largest sample from a single survey. This paper
(Paper I) presents the data, including the optical/ultraviolet light curves and
classification spectra, while Paper II in this series will focus on the
detailed analysis of the light curves and modeling. Our photometry is primarily
taken by the ZTF in the bands, and with additional data from other
ground-based facilities and Swift. The events of our sample cover a redshift
range of , with a median and error (16\% and 84\%
percentiles) . The peak luminosity
covers \,mag, with a median
value of \,mag. Their light curves evolve slowly with
the mean rest-frame rise time of \,days. The
luminosity and time scale distributions suggest that low luminosity SLSNe-I
with peak luminosity \,mag or extremely fast rising events
(\,days) exist but are rare. We confirm previous findings that slowly
rising SLSNe-I also tend to fade slowly. The rest-frame color and temperature
evolution show large scatters, suggesting that the SLSN-I population may have
diverse spectral energy distributions. The peak rest-frame color shows a
moderate correlation with the peak absolute magnitude, i.e. brighter SLSNe-I
tend to have bluer colors. With optical and ultraviolet photometry, we
construct bolometric luminosity and derive a bolometric correction relation
generally applicable for converting -band photometry to bolometric
luminosity for SLSNe-I.Comment: 38 pages, 25 figures, Accepted by AP
Computerized adaptive testing of population psychological distress : simulation-based evaluation of GHQ-30
PURPOSE: Goldberg's General Health Questionnaire (GHQ) items are frequently used to assess psychological distress but no study to date has investigated the GHQ-30's potential for adaptive administration. In computerized adaptive testing (CAT) items are matched optimally to the targeted distress level of respondents instead of relying on fixed-length versions of instruments. We therefore calibrate GHQ-30 items and report a simulation study exploring the potential of this instrument for adaptive administration in a longitudinal setting. METHODS: GHQ-30 responses of 3445 participants with 2 completed assessments (baseline, 7-year follow-up) in the UK Health and Lifestyle Survey were calibrated using item response theory. Our simulation study evaluated the efficiency of CAT administration of the items, cross-sectionally and longitudinally, with different estimators, item selection methods, and measurement precision criteria. RESULTS: To yield accurate distress measurements (marginal reliability at least 0.90) nearly all GHQ-30 items need to be administered to most survey respondents in general population samples. When lower accuracy is permissible (marginal reliability of 0.80), adaptive administration saves approximately 2/3 of the items. For longitudinal applications, change scores based on the complete set of GHQ-30 items correlate highly with change scores from adaptive administrations. CONCLUSIONS: The rationale for CAT-GHQ-30 is only supported when the required marginal reliability is lower than 0.9, which is most likely to be the case in cross-sectional and longitudinal studies assessing mean changes in populations. Precise measurement of psychological distress at the individual level can be achieved, but requires the deployment of all 30 items
Speed Profiles for Deceleration Guidance During Rollout and Turnoff (ROTO)
Two NASA goals are to enhance airport safety and to improve capacity in all weather conditions. This paper contributes to these goals by examining speed guidance profiles to aid a pilot in decelerating along the runway to an exit. A speed profile essentially tells the pilot what the airplane's speed should be as a function of where the airplane is on the runway. While it is important to get off the runway as soon as possible (when striving to minimize runway occupancy time), the deceleration along a speed profile should be constrained by passenger comfort. Several speed profiles are examined with respect to their maximum decelerations and times to reach exit speed. One profile varies speed linearly with distance; another has constant deceleration; and two related nonlinear profiles delay maximum deceleration (braking) to reduce time spent on the runway
Rollout and Turnoff (ROTO) Guidance and Information Displays: Effect on Runway Occupancy Time in Simulated Low-Visibility Landings
This report examines a rollout and turnoff (ROTO) system for reducing the runway occupancy time for transport aircraft in low-visibility weather. Simulator runs were made to evaluate the system that includes a head-up display (HUD) to show the pilot a graphical overlay of the runway along with guidance and steering information to a chosen exit. Fourteen pilots (airline, corporate jet, and research pilots) collectively flew a total of 560 rollout and turnoff runs using all eight runways at Hartsfield Atlanta International Airport. The runs consisted of 280 runs for each of two runway visual ranges (RVRs) (300 and 1200 ft). For each visual range, half the runs were conducted with the HUD information and half without. For the runs conducted with the HUD information, the runway occupancy times were lower and more consistent. The effect was more pronounced as visibility decreased. For the 1200-ft visibility, the runway occupancy times were 13% lower with HUD information (46.1 versus 52.8 sec). Similarly, for the 300-ft visibility, the times were 28% lower (45.4 versus 63.0 sec). Also, for the runs with HUD information, 78% (RVR 1200) and 75% (RVR 300) had runway occupancy times less than 50 sec, versus 41 and 20%, respectively, without HUD information