Method of setting a trigger point for an alarm
AssigneeGeneral Electric Company
InventorsDavid Lacey Doel, Ty Brandon Dubay
Life of this patent
Estimating the term…
Abstract
An approach to setting an alarm limit, which triggers an alarm when a measurement signal reaches the limit. As an example, when a measurement signal is obtained indicating a temperature, the measurement signal can be contaminated with artifacts such noise. The artifacts can falsely indicate that the temperature exceeds a limit, thereby producing false alarms. The invention reduces the number of false alarms, by (1) predicting the likelihood of false alarms for various limits, (2) specifying a desired likelihood, and (3) selecting and using the limit that produces the desired likelihood.
Claims20
In a process wherein (1) a measurement signal is derived from a physical parameter, and (2) an alarm is issued when the measurement signal reaches a limit, said alarm being sometimes false, a method comprising:
- a) obtaining data indicating several alarm accuracies, each associated with a different limit;
- b) specifying a desired accuracy;
- and
- c) selecting the limit associated with the desired accuracy.
A process, comprising:
- a) selecting an alarm limit, based on predictions indicating that the selected alarm limit will attain a specified degree of accuracy;
- and
- b) using the selected alarm limit, issuing actual alarms when a measurement signal reaches a predetermined relationship to the alarm limit.
In a process wherein (1) a measurement signal is derived from a physical parameter, and (2) said measurement signal is used to issue an alarm based on an alarm limit, a method comprising:
- a) using computer simulations of said measurement signal to determine how accuracy of issued alarms changes as the alarm limit changes;
- b) specifying a desired accuracy;
- and
- c) selecting and using in practice an alarm limit which corresponds to the desired accuracy.
In a system wherein a measurement signal nonexactly represents a physical parameter, and said measurement signal is used to trigger an alarm, a method comprising:
- a) determining, for a first alarm level, probability P1 that first alarms issued are valid, using synthesized measurement signals;
- b) determining, for a second alarm level, probability P2 that second alarms issued are valid, using synthesized measurement signals;
- c) using a criterion to select probability P1 or P2, and using the alarm level corresponding to the selected probability in an actual system.
In a system which
- (1) monitors a physical parameter,
- (2) derives a measurement signal from the physical parameter, and
- (2) issues an alert, which is either valid or invalid, when the measurement signal reaches an implemented alert limit,
- a method of establishing said implemented alert limit, comprising:
- a) running multiple computer simulations, using different alert limits, to identify an alert limit which produces a ratio of (valid alerts)/(invalid alerts) which exceeds a predetermined ratio R;
- and
- b) using the identified alert limit as the implemented alert limit.
In a process which
- (1) monitors a physical parameter,
- (2) develops a signal indicating behavior of the physical parameter, and
- (2) issues an alert, which is either valid or invalid, when the signal reaches an implemented alert limit,
- a method of establishing said implemented alert limit, comprising:
- a) estimating the maximum possible number of valid alert limits, MAX, in a time T;
- b) finding a test alert limit having the following properties:
- i) when applied to simulations of said signal in a simulated time period T, the test alert limit produces a number of invalid alerts N;
- and
- ii) the ratio MAX/N is greater than 0.05;
- and
- c) using the test alert limit which was found as the implemented alert limit.
In a process which
- (1) monitors a physical parameter,
- (2) develops a signal indicating behavior of the physical parameter, and
- 2) issues an alert, which is either valid or invalid, when the signal reaches a specified alert limit,
- a method of establishing said specified alert limit, comprising:
- a) estimating maximal number of times, MAX, that said physical parameter can reach the specified alert limit during a time period T;
- b) selecting a test alert limit and estimating the total number of alerts, TOTAL, expected during time period T, given the selected test alert limit;
- c) examining the ratio MAX/TOTAL, and if the ratio does not meet predetermined criteria, repeating the processes of paragraphs (a), (b), and (c) with a different test alert limit.
In a process which
- (1) monitors a signal, and
- (2) issues an alert when the signal reaches a specified alert limit, wherein some alerts are valid and some are invalid,
- a method of establishing said specified alert limit, comprising:
- a) examining several collections of alerts caused by respective alert limits;
- b) from the several collections, selecting a candidate collection in which the alerts are more than five percent valid;
- and
- c) using the alert limits corresponding to the candidate collection as the specified alert limit.
Dependencies are inferred from the claim text.