Diagnostic reasoning based on means-end models: experiences and future prospects

Multilevel flow models (MFM) are graphical models of goals and functions of technical systems. MFM provides a good basis for computer-based supervision and diagnosis, especially in real-time applications, where fast execution and guaranteed worst-case response times are essential. The expressive power of MFM is similar to that of rule-based expert systems, while the explicit representation of means-end knowledge and the graphical nature of the models make the knowledge engineering effort less and the execution efficiency higher than that of standard expert systems. The paper gives an overview of existing MFM algorithms, and different MFM projects which have been performed or are currently in progress