8,484 research outputs found

    Effects of alarms on control of robot teams

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    Annunciator driven supervisory control (ADSC) is a widely used technique for directing human attention to control systems otherwise beyond their capabilities. ADSC requires associating abnormal parameter values with alarms in such a way that operator attention can be directed toward the involved subsystems or conditions. This is hard to achieve in multirobot control because it is difficult to distinguish abnormal conditions for states of a robot team. For largely independent tasks such as foraging, however, self-reflection can serve as a basis for alerting the operator to abnormalities of individual robots. While the search for targets remains unalarmed the resulting system approximates ADSC. The described experiment compares a control condition in which operators perform a multirobot urban search and rescue (USAR) task without alarms with ADSC (freely annunciated) and with a decision aid that limits operator workload by showing only the top alarm. No differences were found in area searched or victims found, however, operators in the freely annunciated condition were faster in detecting both the annunciated failures and victims entering their cameras' fields of view. Copyright 2011 by Human Factors and Ergonomics Society, Inc. All rights reserved

    Effects of Teaching Resourcefulness and Acceptance on Affect, Behavior, and Cognition of Chronically Ill Elders

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    This clinical trial examined changes in affect, behavior, and cognition in 176 chronically ill elders who were randomly assigned to Resourcefulness Training (RT), Acceptance Training (AT), or Diversional Activities (DA). The RT group improved on affect (t(1,42) = 4.91; p \u3c .001) and cognition (t(1,42) = 2.03; p\u3c .05) and these effects lasted 12 weeks. The AT group improved on affect (t(1,36) = 3.08; p \u3c .01), but this improvement did not persist. The RT and AT groups both showed positive behavior changes after six weeks. There were no changes in the DA group. The findings suggest that teaching elders resourcefulness and acceptance of chronic conditions may promote healthy functioning and improve their quality of life

    Neutron transition strengths of 21+2^+_1 states in the neutron rich Oxygen isotopes determined from inelastic proton scattering

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    A coupled-channel analysis of the 18,20,22^{18,20,22}O(p,p′)(p,p') data has been performed to determine the neutron transition strengths of 21+^+_1 states in Oxygen targets, using the microscopic optical potential and inelastic form factor calculated in the folding model. A complex density- and \emph{isospin} dependent version of the CDM3Y6 interaction was constructed, based on the Brueckner-Hatree-Fock calculation of nuclear matter, for the folding model input. Given an accurate isovector density dependence of the CDM3Y6 interaction, the isoscalar (δ0\delta_0) and isovector (δ1\delta_1) deformation lengths of 21+^+_1 states in 18,20,22^{18,20,22}O have been extracted from the folding model analysis of the (p,p′)(p,p') data. A specific NN-dependence of δ0\delta_0 and δ1\delta_1 has been established which can be linked to the neutron shell closure occurring at NN approaching 16. The strongest isovector deformation was found for 21+^+_1 state in 20^{20}O, with δ1\delta_1 about 2.5 times larger than δ0\delta_0, which indicates a strong core polarization by the valence neutrons in 20^{20}O. The ratios of the neutron/proton transition matrix elements (Mn/MpM_n/M_p) determined for 21+^+_1 states in 18,20^{18,20}O have been compared to those deduced from the mirror symmetry, using the measured B(E2)B(E2) values of 21+^+_1 states in the proton rich 18^{18}Ne and 20^{20}Mg nuclei, to discuss the isospin impurity in the 21+2^+_1 excitation of the A=18,T=1A=18,T=1 and A=20,T=2A=20,T=2 isobars.Comment: Version accepted for publication in Physical Review

    Microbial and biogeochemical responses to projected future nitrate enrichment in the California upwelling system

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    Coastal California is a dynamic upwelling region where nitrogen (N) and iron (Fe) can both limit productivity and influence biogeochemistry over different spatial and temporal scales. With global change, the flux of nitrate from upwelling is expected to increase over the next century, potentially driving additional oceanic regions toward Fe limitation. In this study we explored the effect of changes in Fe/N ratio on native phytoplankton from five currently Fe-replete sites near the major California upwelling centers at Bodega Bay and Monterey Bay using nutrient addition incubation experiments. Despite the high nitrate levels (13–30 μ M) in the upwelled water, phytoplankton at three of the five sites showed increased growth when 10 μ M nitrate was added. None of the sites showed enhanced growth following addition of 10 nM Fe. Nitrate additions favored slow sinking single-celled diatoms over faster sinking chain-forming diatoms, suggesting that future increases in nitrate flux could affect carbon and silicate export and alter grazer populations. In particular, solitary cells of Cylindrotheca were more abundant than the toxin-producing genus Pseudonitzschia following nitrate addition. These responses suggest the biogeochemistry of coastal California could change in response to future increases in nitrate, and multiple stressors like ocean acidification and hypoxia may further result in ecosystem shifts

    Influence of cultural factors in dynamic trust in automation

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    The use of autonomous systems has been rapidly increasing in recent decades. To improve human-automation interaction, trust has been closely studied. Research shows trust is critical in the development of appropriate reliance on automation. To examine how trust mediates the human-automation relationships across cultures, the present study investigated the influences of cultural factors on trust in automation. Theoretically guided empirical studies were conducted in the U.S., Taiwan and Turkey to examine how cultural dynamics affect various aspects of trust in automation. The results found significant cultural differences in human trust attitude in automation
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