Jan Bredereke

Learn More
Not only in aviation psychology, mode confusion is recog-nised as a significant safety concern. The notion is used intuitively in the pertinent literature, but with surprisingly different meanings. We present a rigorous way of modelling the human and the machine in a shared-control system. This enables us to propose a precise definition of " mode " and "(More)
Mode confusions are a significant safety concern in safety-critical systems, for example in aircraft. A mode confusion occurs when the observed behaviour of a technical system is out of sync with the behaviour of the user's mental model of it. But the notion is described only informally in the literature. We present a rigorous way of modelling the user and(More)
In general, the potential parallelism expressed in a speciication should be as high as possible in order to allow for most eecient implementations. We argue that there are currently important limitations of expressing concurrency in Estelle. Therefore, we propose a minor, fully compatible extension of Estelle, which allows a signiicantly higher degree of(More)
The causes for feature interactions are many, therefore several remedies will have to be applied together. In this paper, we investigate the architecture of the users' interface of a telephone switching system and tackle a certain kind of feature interactions by employing a more modular structure for the design of the system and its features. We propose to(More)
Feature interaction problems are currently a major roadblock to extending and changing telephone switching systems, which have to follow market needs quickly. Such problems appear already in the requirements speciications. We avoid certain kinds of feature interactions by employing a more modular speciication structure. First, we show how the details of the(More)