Computer-based diagnostic expert system organized according to Bayesian theory
First Claim
1. An apparatus for determining the status of a system together with the probability of that status from time-dependent observables of the system, said apparatus comprising a computer, said computer including first memory means for storing a knowledge base, said knowledge base comprising data representative of a set of possible states of a system in association with probabilities that time-variable patterns of said observables will be present given the occurrence of such states, said apparatus including means for obtaining observables indicative of the operation of the system at a succession of different times and means for representing said observables in a time-succession of digitized codes, said apparatus also including diagnostic means responsive to data selected from said knowledge base and to said succession of digitized codes for generating a second set of digitized codes representing probability distributions over the set of said states and for updating said probability distributions as a function of time.
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Abstract
An expert system is organized according to Bayes'"'"' theorem. The system includes a diagnostic module that generates a diagnosis in the form of probability distributions. The diagnostic module also is responsive to evidence in the form of discretized time trajectories in the value space of the observable variables. The diagnostic module is also responsive to data from a knowledge base that represents the trajectories of the possible states of the system and the associated values of the likelihood that the various trajectories of observed evidence would be present if the system were in that state.
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Citations
10 Claims
- 1. An apparatus for determining the status of a system together with the probability of that status from time-dependent observables of the system, said apparatus comprising a computer, said computer including first memory means for storing a knowledge base, said knowledge base comprising data representative of a set of possible states of a system in association with probabilities that time-variable patterns of said observables will be present given the occurrence of such states, said apparatus including means for obtaining observables indicative of the operation of the system at a succession of different times and means for representing said observables in a time-succession of digitized codes, said apparatus also including diagnostic means responsive to data selected from said knowledge base and to said succession of digitized codes for generating a second set of digitized codes representing probability distributions over the set of said states and for updating said probability distributions as a function of time.
- 6. A method of diagnosing the instant state of a system having a state which varies with time using a computer having a memory, comprising the steps of storing in said memory a knowledge base comprising sets of digitized data representative of the possible states of said system in time-dependent form in association with the probabilities that certain observables will be present given the occurrence of the associated state, inputting into said computer evidence in a time-dependent form, and providing a probability distribution of the possible states of said system responsive to said data from said knowledge base and to said evidence in time-dependent form.
Specification