A BSTRA CT
This paper is devoted to fault tree synthesis and is split up into three parts. Part I starts with the introduction of component models that show all fault propagation through the components and fault initiation by the components in both directions (upstream and downstream ). Subsequently, it is shown how to create system models that interconnect a system's components and environmental variables. Then a fault tree construction algorithm is introduced which is able to generate fault trees from the given system and component models in two steps. First a causal tree is constructed showing the propagation paths for all basic events leading to any deviation in the top parameter. All control loops (feedback and feedforward loops) in this causal tree must be traced prior to any fault tree construction since the)" might prevent some faults from reaching the top parameter. They consequently require a special treatment. Part lends showing how to adapt the causal trees for these loops. Part H discusses the final step of the fault tree construction algorithm, i.e. it shows how fault trees can be abstracted from the causal diagram, and ends with a comprehensive example. Finally, Part III discusses a method for real-time fault location which is based on the causal tree construction procedure introduced in Part L
1 REAL-TIME FAULT LOCATION
Fault tree synthesis has proved to be an adequate tool in extracting the reliability figures of systems. However, up to now, it has seldom been used for real-time fault location in running systems, because fault trees describe 161 Reliability Engineering and System Safety