Christian Leuxner

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In computer science the notion of adaptive systems has been used in different contexts for many years now. Although there is some intuitive, common understanding of the notion, a precise and universally practicable definition is still missing. More precisely, previous definitions fail to strictly differentiate between adaptive and non-adaptive systems. We(More)
—Autonomic Computing (AC) is an emerging paradigm aiming at simplifying the administration of complex computer systems. Efforts required to deploy and maintain complex systems are usually high. Autonomic Computing may help to reduce these efforts by allowing administrators to define abstract policies and then enable systems to configure, optimize and(More)
Within this paper, we present a structured, formal model for the specification and analysis of work flows. The model provides a graphical representation supporting a modular description of work flows together with a formal semantics accurately reflecting their execution and laying the foundation for tool support. Methodically relevant concepts such as(More)
The concept of Ubiquitous Computing, also called Ubicomp for brevity, describes a new paradigm on the usage of computer based systems, which is – in comparison to the usage of conventional computers – characterized by an enhanced degree of user centering, thus enabling users to benefit from computer usage and support in as many situations as possible. The(More)
Service-oriented architectures (SOA) have received much attention for providing specification principles in order to develop flexible and interoperable software systems. This is achieved by concentrating on " non-technical " concepts of the application domain in order to structure software systems in a functional, business process-oriented manner-thereby(More)
This paper considers the behavior planning of robots deployed to act autonomously in highly dynamic environments. For such environments and complex tasks, model-based planning requires relatively complex world models to capture all relevant dependencies. The efficient generation of decisions, such that realtime requirements are met, has to be based on(More)
Today's software systems tend more and more to comprise a multitude of different, often interfering functionalities. Especially in the case of embedded systems with their high requirements on safety this imposes additional risks for unwanted system behavior. Use cases are a common way to describe system functionalities in very early phases of the system(More)
The consistent specification of reactive, context-aware systems is still a challenging and error-prone task. One reason for this observation is, that those systems are typically involved in complex user interactions and support multi-variant work flows of humans and other technical systems. On the one hand, it is necessary to capture all system functions(More)