Integrating diagnostic knowledge

Three model-based diagnostic approaches have been developed: heuristic probing, simulation using truth maintenance, and simulation using constraint relaxation. Heuristic probing uses a variety of information to determine the order in which measurements are made. Truth maintenance uses complex simulation models to compare measured and expected signal values and then derive a diagnosis. Simulation with constraint relaxation is similar to truth maintenance, but heuristics can be applied to limit the amount of simulation performed. The key feature of each approach is the elimination of manual diagnostic test programming.<
>