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— The complexity of present day embedded systems (continuous processes controlled by digital processors), and the increased demands on their reliability motivate the need for monitoring and fault isolation capabilities in the embedded processors. This paper develops monitoring, prediction, and fault isolation methods for abrupt faults in complex dynamic(More)
Modeling and simulation are quickly becoming the primary enablers for complex system design. They allow the representation of intricate knowledge at various levels of abstraction and allow automated analysis as well as synthesis. The heterogeneity of the design process, as much as of the system itself, however, requires a manifold of formalisms tailored to(More)
To model complex mixed continuoussdiscrete, hybrid, systems, the continuous part can be described by diier-ential and algebraic equations using an object-oriented modeling language such as Modelica. It is shown how a discrete formalism such as Petri nets can be incorporated by describing all components by strictly local equations. This allows a unifying(More)
Bond graphs are a powerful formalism for modeling the continuous dynamics of physical systems. To model fast continuous changes as discontinuities, hybrid bond graphs introduce an ideal switching element, the controlled junction, that may inhibit power transfer by enforcing its common variable to be zero. When bond graph storage components become dependent(More)
—This paper discusses a method for fault detection and isolation (FDI) in continuous dynamic systems. A key aspect of this approach is the coupling of a qualitative diagnosis engine and a monitoring system that computes symbolic feature values through a signal-to-symbol transformation on the continuously sampled measurement data. Signal analysis techniques(More)
Computational models of embedded control systems often combine continuous-time with discrete-event behavior, mathematically representing hybrid dynamic systems. An essential element of numerical simulation of a hybrid dynamic system is the generation of discrete events from continuous variables that exceed thresholds. In particular, the occurrence of such(More)
The design of embedded systems is often based on the development of a detailed formal system specification. Considerable effort is spent to ensure the correctness of this specification. However, the actual implementation of the specification and later maintenance is usually done using traditional programming and more often diverges from the specification.(More)