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Modern embedded computing systems tend to be heterogeneous in the sense of being composed of subsystems with very different characteristics, that communicate and interact in a variety of ways—synchronous or asynchronous, buffered or unbuffered, etc. Obviously, when designing such systems, a modeling language needs to reflect this heterogeneity. Today’s(More)
Control systems are becoming increasingly complex from both the control and computer science perspectives. Today, even seemingly simple embedded control systems often contain a multitasking real-time kernel and support networking. At the same time, the market demands that the cost of the system be kept at a minimum. For optimal use of computing resources,(More)
A scheduling architecture for real-time control tasks is proposed. The scheduler uses feedback from execution-time measurements and feedforward from workload changes to adjust the sampling periods of the control tasks so that the combined performance of the controllers is optimized. The performance of each controller is described by a cost function. Based(More)
Based on recent advances in control theory, we propose the notion of jitter margin for periodic control tasks. The jitter margin is defined as a function of the amount of constant delay in the control loop, and it describes how much additional time-varying delay can be tolerated before the loop goes unstable. Combined with scheduling theory, the jitter(More)
Video coding technology in the last 20 years has evolved producing a variety of different and complex algorithms and coding standards. So far the specification of such standards, and of the algorithms that build them, has been done case by case providing monolithic textual and reference software specifications in different forms and programming languages.(More)
This paper presents the OpenDF framework and recalls that dataflow programming was once invented to address the problem of parallel computing. We discuss the problems with an imperative style, von Neumann programs, and present what we believe are the advantages of using a dataflow programming model. The CAL actor language is briefly presented and its role(More)
The paper presents a feedback scheduling mechanism in the context of co-design of the scheduler and the control tasks. We are particularly interested in controllers where the execution time may change abruptly between different modes, such as in hybrid controllers. The proposed solution attempts to keep the CPU utilization at a high level, avoid overload,(More)