Objectives: The detection response task (DRT) is a method for measuring attentional effects of secondary tasks on a driver's cognitive load by measuring response times and hit rates to different types of stimuli as indirect indicators of increased cognitive load. ISO 17488 (International Organization for Standardization 2016) only provides guidelines for the technical implementation and measurement methods for the visual and tactile versions (use of visual and tactile stimuli) of the DRT method. This article presents a study with the goal of finding the most appropriate auditory stimulus for the implementation of an auditory version of the DRT method.
Methods: This article presents the results of an experiment in which responses to 7 different auditory DRT stimuli—varying in frequency—were compared while inducing users' cognitive load with a modified n-back task. The experiment was conducted in a surrogate driving environment and in a within-subject design. Response times, hit rates, and secondary task performances were observed as indicators of increased cognitive load.
Results: Significantly shorter response times were found for the white noise signal compared to single-frequency signals. However, the largest differences in response times, for trials without and with a cognitive task, were found for 4- and 8-kHz single-frequency signals. No significant differences were found for hit rates and secondary task performances between the different stimuli.
Conclusions: Consistent significant differences in response times for all tested stimuli prove that the auditory DRT variant is also sensitive to changes in cognitive load. The mean increase in response times of more than 25% for 4- and 8-kHz signals for trials with a cognitive task compared to trials without one indicates that one of these signals could be used as a potential auditory stimulus for the auditory DRT variant. 相似文献
The review analysis of twenty two irrigation efficiency (IE) studies carried out in the Ebro River Basin shows that IE is
low (average IE)avg(= 53%) in surface-irrigated areas with high-permeable and shallow soils inadequate for this irrigation system, high (IE)avg(= 79%) in surface-irrigated areas with appropriate soils for this system, and very high (IE)avg(= 94%) in modern, automated and well managed sprinkler-irrigated areas. The unitary salt (total dissolved solids) and nitrate
loads exported in the irrigation return flows (IRF) of seven districts vary, depending on soil salinity and on irrigation
and N fertilization management, between 3–16 Mg salt/ha⋅ year and 23–195 kg NO)3−-N/ha⋅ year, respectively. The lower nitrate loads exported from high IE districts show that a proper irrigation design and
management is a key factor to reduce off-site nitrogen pollution. Although high IE’s also reduce off-site salt pollution,
the presence of salts in the soil or subsoil may induce relatively high salt loads (≥14 Mg/ha⋅ year) even in high IE districts.
Two important constrains identified in our revision were the short duration of most surveys and the lack of standards for
conducting irrigation efficiency and mass balance studies at the irrigation district level. These limitations {emphasize the
need for the establishment of a permanent and standardized network of drainage monitoring stations for the appropriate off-site
pollution diagnosis and control of irrigated agriculture. 相似文献
