Karsten Albers

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This paper presents a new approach to understand the event stream model. Additionally a new approximation algorithm for the feasibility test of the sporadic and the generalized multiframe task system scheduled by earliest deadline first is presented. The new algorithm has a polynomial complexity to solve the Co-NP hard problem of schedulability analysis.(More)
This paper presents new fast exact feasibility tests for uniprocessor real-time systems using preemptive EDF scheduling.Task sets which are accepted by previously described sufficient tests will be evaluated in nearly the same time as with the old tests by the new algorithms. Many task sets are not accepted by the earlier tests despite them beeing(More)
One of the important aspects of schedulability analysis is the model used to describe the system and its timing behavior. On one side, the accuracy of the test strongly depends on the accuracy of the model. On the other side, a detailed model could lead to an inaccaptable evaluation time. In this paper we propose a new model, the hierarchical event streams,(More)
We propose a model and method to determine the temporal distribution of task activations occurring within an event driven real time system. As real time systems even in safety critical applications are becoming increasingly complex, it becomes increasingly important to get a better understanding of the activity within these systems. The event stream model(More)
Fast real-time feasibility tests and analysis algorithms are necessary for a high acceptance of the formal techniques by industrial software engineers. This paper presents a possibility to reduce the computation time required to calculate the worst-case response time of a task in a fixed-priority task set with jitter by a considerable amount of time. The(More)
An important step during the design of embedded systems is to allocate suitable architectural components and to optimally bind functions (tasks) to these components. This design step is called system synthesis. The automation of system synthesis is limited in recent research by developing models only for standard optimization algorithms. This paper(More)
The performance of feasibility tests is crucial in many applications. When using feasibility tests online only a limited amount of analysis time is available. Run-time efficiency is also needed for testing the feasibility of many different task sets, which is the case in system synthesis tools. We propose a fast uni-processor feasibility test using static(More)