Walking is the most natural way of moving within a virtual environment (VE). Mapping the user’s movement one-to-one to the real world clearly has the drawback that the limited range of the tracking sensors and a rather small working space in the real word restrict the users’ interaction. In this paper we introduce concepts for virtual locomotion interfaces that support exploration of large-scal...

Previous analyses on the gauge invariance of the action for a generally covariant system are generalized. It is shown that if the action principle is properly improved, there is as much gauge freedom at the endpoints for an arbitrary gauge system as there is for a system with “internal” gauge symmetries. The key point is to correctly identify the boundary conditions for the allowed histories an...

OSCAR is a fully implemented architecture for a cognitive agent, based largely on the author’s work in philosophy concerning epistemology and practical cognition. The seminal idea is that a generally intelligent agent must be able to function in an environment in which it is ignorant of most matters of fact. The architecture incorporates a general-purpose defeasible reasoner, built on top of an...

the successful adoption of e-learning systems is mainly dependent on the learners’ attitude and willingness to use them. this survey was conducted to investigate agricultural extension workers’ attitudes toward using e-learning for on-the-job training in iran and factors which affect it. using the stratified sampling technique a sample of 379 extension workers were selected from six provinces. ...