SUBSYSTEM-LEVEL MODEL-BASED DIAGNOSIS

1 . A computer-implemented method for diagnosing faults in a physical system, the method comprising:

obtaining, by a computer, a model of the physical system comprising a plurality of components;

performing a structural analysis on the model to decompose the model into multiple independent subsystem models, wherein a subsystem model corresponds to a subsystem comprising a subset of the plurality of components;

performing, in parallel, a fault-diagnosis operation on each subsystem based on the corresponding subsystem model; and

generating a diagnostic output indicating one or more components within the physical system being faulty based on outcome of the fault-diagnosis operation on each subsystem.

2 . The method of claim 1 , wherein performing the fault-diagnosis operation comprises:

estimating parameters of the subsystem model; and

determining a faulty parameter based on the estimated parameters and their corresponding loss functions.

3 . The method of claim 1 , wherein performing the structural analysis on the model comprises performing a causal analysis of a plurality of equations associated with the model.

4 . The method of claim 3 , wherein performing the causal analysis comprises generating a block lower triangular (BLT) form of the plurality of equations.

5 . The method of claim 1 , wherein decomposing the model into multiple independent subsystem models comprises identifying, for each subsystem model, a number of input variables.

6 . The method of claim 5 , further comprising installing one or more sensors corresponding to the identified input variables.

7 . The method of claim 5 , further comprising:

obtaining sensor measurement results associated with the identified input variables; and

using the sensor measurement results as inputs of the subsystem model during the fault-diagnosis operation.

8 . A non-transitory computer-readable storage medium storing instructions that when executed by a computer cause the computer to perform a method for generating test vectors for a computational system, the method comprising:

obtaining, by a computer, a model of the physical system comprising a plurality of components;

performing a structural analysis on the model to decompose the model into multiple independent subsystem models, wherein a subsystem model corresponds to a subsystem comprising a subset of the plurality of components;

performing, in parallel, a fault-diagnosis operation on each subsystem based on the corresponding subsystem model; and

generating a diagnostic output indicating one or more components within the physical system being faulty based on outcome of the fault-diagnosis operation on each subsystem.

9 . The non-transitory computer-readable storage medium of claim 8 , wherein performing the fault-diagnosis operation comprises:

estimating parameters of the subsystem model; and

determining a faulty parameter based on the estimated parameters and their corresponding loss functions.

10 . The non-transitory computer-readable storage medium of claim 8 , wherein performing the structural analysis on the model comprises performing a causal analysis of a plurality of equations associated with the model.

11 . The non-transitory computer-readable storage medium of claim 10 , wherein performing the causal analysis comprises generating a block lower triangular (BLT) form of the plurality of equations.

12 . The non-transitory computer-readable storage medium of claim 8 , wherein decomposing the model into multiple independent subsystem models comprises identifying, for each subsystem model, a number of input variables.

13 . The non-transitory computer-readable storage medium of claim 12 , wherein the method further comprises:

obtaining sensor measurement results associated with the identified input variables; and

using the sensor measurement results as inputs of the subsystem model during the fault-diagnosis operation.

14 . A computer system for diagnosing faults in a physical system, the computer system comprising:

a processor; and

a storage device coupled to the processor and storing instructions, which when executed by the processor cause the processor to perform a method, the method comprising:

obtaining, by a computer, a model of the physical system comprising a plurality of components;

performing a structural analysis on the model to decompose the model into multiple independent subsystem models, wherein a subsystem model corresponds to a subsystem comprising a subset of the plurality of components;

performing, in parallel, a fault-diagnosis operation on each subsystem based on the corresponding subsystem model; and

generating a diagnostic output indicating one or more components within the physical system being faulty based on outcome of the fault-diagnosis operation on each subsystem.

15 . The computer system of claim 14 , wherein performing the fault-diagnosis operation comprises:

estimating parameters of the subsystem model; and

determining a faulty parameter based on the estimated parameters and their corresponding loss functions.

16 . The computer system of claim 15 , wherein determining the faulty parameter further comprises:

computing, for each parameter, an empirical probability based on the loss functions; and

determining a parameter with a maximum empirical probability as the faulty parameter.

17 . The computer system of claim 14 , wherein performing the structural analysis on the model comprises performing a causal analysis of a plurality of equations associated with the model.

18 . The computer system of claim 16 , wherein performing the causal analysis comprises generating a block lower triangular (BLT) form of the plurality of equations.

19 . The computer system of claim 14 , wherein decomposing the model into multiple independent subsystem models comprises identifying, for each subsystem model, a number of input variables.

20 . The computer system of claim 18 , wherein the method further comprises:

obtaining sensor measurement results associated with the identified input variables; and

using the sensor measurement results as inputs of the subsystem model during the fault-diagnosis operation.