Title : Cognitive theory for the SemWeb: Natural Categories

Presenter Mark van Assem
Abstract In this presentation I will not discuss my own work but rather a cognitive theory that might be relevant to ontological theory. It is the work of Elisabeth Rosch on how people make categorizations; she posits that there exist so-called "natural categories" (classes/concepts) with special properties. I will present her theory, and work by Rebecca Green on (a) automatically determining natural categories in thesauri; and (b) utilizing natural categories for mapping scenarios. Further, I'd like to brainstorm with you about what more things you can do if you know which concepts in a hierarchy are natural categories.

Title : Effects of Task Performance and Task Complexity on the Validity of Computational Models of Attention

Presenter Peter-Paul van Maanen
Abstract Computational models of attention can be used as a component of decision support systems. For accurate support, a computational model of attention has to be valid and robust. The effects of task performance and task complexity on the validity of three different computational models of attention were investigated in an experiment. The gaze-based model uses gaze behavior to determine where the subject's attention is, the task-based model uses information about the task and the combined model uses both gaze behavior and task information. While performing a tactical compilation task, participants had to indicate to what set of objects their attention was allocated. The indications of the participants were compared with the estimations of the three models. The results show that overall, the estimation of the combined model was better than that of the other two models. Contrary to what was expected, the performance of the models was not different for good and poor performers and was not different for a simple and complex scenario. The difference in complexity and performance might not have been strong enough. Further research is needed to determine if improvement of the combined model is possible with additional features and if computational models of attention can effectively be used in decision support systems. This can be done using a similar validation methodology as presented in this paper.
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