36,936 research outputs found
Human factors considerations for the use of color in display systems
Identified and assessed are those human factor considerations impacting an operator's ability to perform when information is displayed in color as contrasted to monochrome (black and white only). The findings provide valuable guidelines for the assessment of the advantages (and disadvantages) of using a color display system. The use of color provides an additional sensory channel (color perception) which is not available with black and white. The degree to which one can exploit the use of this channel is highly dependent on available display technology, mission information display requirements, and acceptable operational modes
Observational asteroseismology of hot subdwarf stars
Hot subdwarf stars are particularly challenging for asteroseismology due to
their rapid pulsation periods, intrinsic faintness and relative rarity both in
the field and in clusters. These features have ensured that the preferred
method of observation up to now has been white-light photometry, and all
asteroseismological solutions to date have been made by model fitting of the
frequency spectrum. Several attempts have been made to perform asteroseismology
using time-resolved spectroscopy on the brightest of these stars, but with
modest results. A few attempts at simultaneous multi-color photometry have also
been made to identify modes with the amplitude ratio method. We will review the
most recent observational results and progress in improving the observational
methods for ground-based asteroseismology of these compact pulsators.Comment: 8 pages, to appear in Astronomische Nachrichten, Vol. 331, 102
Optimizing the Use of an Artificial Tongue-Placed Tactile Biofeedback for Improving Ankle Joint Position Sense in Humans
The performance of an artificial tongue-placed tactile biofeedback device for
improving ankle joint position sense was assessed in 12 young healthy adults
using an active matching task. The underlying principle of this system consists
of supplying individuals with supplementary information about the position of
the matching ankle relative to the reference ankle position through a
tongue-placed tactile output device generating electrotactile stimulation on a
36-point (6 X 6) matrix held against the surface of the tongue dorsum.
Precisely, (1) no electrodes were activated when both ankles were in a similar
angular position within a predetermined "angular dead zone" (ADZ); (2) 12
electrodes (2 X 6) of the anterior and posterior zones of the matrix were
activated (corresponding to the stimulation of the front and rear portion of
the tongue) when the matching ankle was in a too plantarflexed and dorsiflexed
position relative to the reference ankle, respectively. Two ADZ values of 0.5
degrees and 1.5 degrees were evaluated. Results showed (1) more accurate and
more consistent matching performances with than without biofeedback and (2)
more accurate and more consistent ankle joint matching performances when using
the biofeedback device with the smaller ADZ valu
Agricultural resources investigations in northern Italy and southern France (Agreste Project)
The author has identified the following significant results. The vegetation structure of rice was investigated and interpreted in dynamic terms as a significant factor governing the distribution of solar energy thoughout the canopy and therefore conditions the final yield. Radiometric characteristics of rice culture were described for various stages of development in relation to the vegetation structure in an attempt to establish correlations between data of total biomass and of grain yield. Qualitative classification results were encouraging although the discrimination achieved was far from complete
Sensory supplementation system based on electrotactile tongue biofeedback of head position for balance control
The present study aimed at investigating the effects of an artificial head
position-based tongue-placed electrotactile biofeedback on postural control
during quiet standing under different somatosensory conditions from the support
surface. Eight young healthy adults were asked to stand as immobile as possible
with their eyes closed on two Firm and Foam support surface conditions executed
in two conditions of No-biofeedback and Biofeedback. In the Foam condition, a
6-cm thick foam support surface was placed under the subjects' feet to alter
the quality and/or quantity of somatosensory information at the plantar sole
and the ankle. The underlying principle of the biofeedback consisted of
providing supplementary information about the head orientation with respect to
gravitational vertical through electrical stimulation of the tongue. Centre of
foot pressure (CoP) displacements were recorded using a force platform. Larger
CoP displacements were observed in the Foam than Firm conditions in the two
conditions of No-biofeedback and Biofeedback. Interestingly, this destabilizing
effect was less accentuated in the Biofeedback than No-biofeedback condition.
In accordance with the sensory re-weighting hypothesis for balance control, the
present findings evidence that the availability of the central nervous system
to integrate an artificial head orientation information delivered through
electrical stimulation of the tongue to limit the postural perturbation induced
by alteration of somatosensory input from the support surface
Spacing affects some but not all visual searches: Implications for theories of attention and crowding
We investigated the effect of varying interstimulus spacing on an upright among inverted face search and a red–green among green–red bisected disk search. Both tasks are classic examples of serial search; however, spacing affects them very differently: As spacing increased, face discrimination performance improved significantly, whereas performance on the bisected disks remained poor. (No effect of spacing was observed for either a red among green or an L among + search tasks, two classic examples of parallel search.) In a second experiment, we precued the target location so that attention was no longer a limiting factor: Both serial search tasks were now equally affected by spacing, a result we attribute to a more classical form of crowding. The observed spacing effect in visual search suggests that for certain tasks, serial search may result from local neuronal competition between target and distractors, soliciting attentional resources; in other cases, serial search must occur for another reason, for example, because an item-by-item, attention-mediated recognition must take place. We speculate that this distinction may be based on whether or not there exist neuronal populations tuned to the relevant target–distractor distinction, and we discuss the possible relations between this spacing effect in visual search and other forms of crowding
An evaluation of multiband photography for rock discrimination
The author has identified the following significant results. With the advent of ERTS and Skylab satellites, multiband imagery and photography have become readily available to geologists. The ability of multiband photography to discriminate sedimentary rocks was examined. More than 8600 in situ measurements of band reflectance of the sedimentary rocks of the Front Range, Colorado, were acquired. Statistical analysis of these measurements showed that: (1) measurements from one site can be used at another site 100 miles away; (2) there is basically only one spectral reflectance curve for these rocks, with constant amplitude differences between the curves; and (3) the natural variation is so large that at least 150 measurements per formation are required to select best filters. These conclusions are supported by subjective tests with aerial multiband photography. The designed multiband photography concept for rock discrimination is not a practical method of improving sedimentary rock discrimination capabilities
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