Aspects of diagnostic schemes for biomedical and engineering systems

The paper considers aspects of work carried out on projects in medical diag nostics and engineering fault detection and control, and shows the developm ent of some ideas in signal processing and diagnostic techniques; in partic ular regarding models, estimators and decision schemes. The fact that analy sis of human biological systems is restricted by powerful ethical and legal constraints would seem to lead to fundamental differences of approach to m edical and engineering problems. Tn the reseal-ch considered this did not s eem to be a dominant issue. The use of system simulators as reference stand ards, and blackboard schemes for knowledge integration, has shown to advant age in both fields. Methods for increasing the usefulness of limited data h ave been successfully applied to decreasing the cost associated with sensor s for a given standard of diagnostic reliability. The science of engineerin g control and diagnostics has benefited front the use of observers based on state-space descriptions of the system. An observer provides an alternativ e reference model which has been used to generate residuals when faults occ ur. A new technique employing sliding-mode observers to recreate fault sign als is introduced. This idea is extended for use in a medical context.