| 1. |
- Dudley, Bernard J., et al.
(författare)
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Measurements of uncertainty in macrophyte metrics used to assess European lake water quality
- 2013
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Ingår i: Hydrobiologia. - : Springer Science and Business Media LLC. - 0018-8158 .- 1573-5117. ; 704:1, s. 179-191
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Tidskriftsartikel (refereegranskat)abstract
- Uncertainty is an important factor in ecological assessment, and has important implications for the ecological classification and management of lakes. However, our knowledge of the effects of uncertainty in the assessment of different ecological indicators is limited. Here, we used data from a standardized campaign of aquatic plant surveys, in 28 lakes from 10 European countries, to assess variation in macrophyte metrics across a set of nested spatial scales: countries, lakes, sampling stations, replicate transects, and replicate samples at two depth-zones. Metrics investigated in each transect included taxa richness, maximum depth of colonisation and two indicators of trophic status: Ellenberg’s N and a metric based on phosphorus trophic status. Metrics were found to have a slightly stronger relationship to pressures when they were calculated on abundance data compared to presence/absence data. Eutrophication metrics based on helophytes were found not to be useful in assessing the effects of nutrient pressure. These metrics were also found to vary with the depth of sampling, with shallower taxa representing higher trophic status. This study demonstrates the complex spatial variability in macrophyte communities, the effect of this variability on the metrics, and theimplications to water managers, especially in relation to survey design.
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| 3. |
- Wykowska, Agnieszka, et al.
(författare)
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How humans optimize their interaction with the environment : The impact of action context on human perception
- 2011
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Ingår i: International Journal of Social Robotics. - : Springer Science and Business Media LLC. - 1875-4791 .- 1875-4805. ; 3:3, s. 223-231
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Tidskriftsartikel (refereegranskat)abstract
- This paper reports empirical findings on human performance in an experiment comprising a perceptual task and a motor task. Such findings should be considered in design of robots, since drawing inspiration from natural solutions not only should prove beneficial for artificial systems but also human-robot interaction should then become more efficient and safe. Humans have developed various mechanisms to optimize the way actions are performed and the effects they induce. Optimization of action planning (e.g., grasping, reaching or lifting objects) requires efficient selection of action-relevant features. Selection might also depend on the environmental context in which an action takes place. The present study investigated how action context influences perceptual processing in action planning. The experimental paradigm comprised two independent tasks: (1) a perceptual visual search task and (2) a grasping or a pointing movement. Reaction times in the visual search task were measured as a function of the movement type (grasping vs. pointing) and context complexity (context varying along one dimension vs. context varying along two dimensions). Results showed that action context influenced reaction times, which suggests a close bidirectional link between action and perception as well as an impact of environmental action context on perceptual selection in the course of action planning. These findings are discussed in the context of application for robotics and design of users' interfaces.
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