Method and device for finding spurious maintenance messages

• US 5,610,923 A
• Filed: 01/25/1995
• Issued: 03/11/1997
• Est. Priority Date: 02/01/1994
• Status: Expired due to Term

• Current Assignee: Airbus Operations SAS (Airbus SE)
• Original Assignee: Aerospatiale Societe Nationale Industrielle
• Inventors: Callay, Christian
• Primary Examiner(s): Beausoliel, Jr., Robert W.
• Assistant Examiner(s): CHUNG, PHUNG M
• Application Number:
  US08/377,609
• Time in Patent Office: 776 Days
• Field of Search: 371/5.1, 371/5.2, 371/67.1, 371/48, 395/184.01, 395/185.01
• US Class Current: 714/704
• CPC Class Codes: G06F 11/0736 in functional embedded systems, i.e. in a data processing system designed as a combination of hardware and software dedicated to performing a certain function testing or monitoring of automated control systems G05B23/02
• CPC Class Codes: G06F 11/0739 in a data processing system embedded in automotive or aircraft systems
• CPC Class Codes: G06F 11/0751 Error or fault detection not based on redundancy power supply failures G06F1/30; network fault management H04L41/06
• CPC Class Codes: G06F 11/2294 by remote test
• CPC Class Codes: H04L 1/24 Testing correct operation

Abstract

A device (1) for determining whether a maintenance message generated during an operating cycle of a system by a maintenance device (2) monitoring the system is or is not representative of a real fault in the system. The device (1) includes a comparator (D) which compares a short-term occurrence rate of the message to a long-term occurrence rate of the message, for each maintenance message generated, and determining whether the message is or is not representative of a real fault. The occurrence rates are calculated by a computer (CAL) on the basis of information contained in memories (M1, M2, MN) and indicate the presence or non-presence of the message in the course of predicting cycles.

Claims

1. A method for determining whether a maintenance message generated, during an operating cycle of a system, by a maintenance device monitoring said system, is representative of a real fault in said system or whether this maintenance message is spurious, wherein, at the end of said operating cycle, the method comprising the steps of:

(a) determining a long-term occurrence rate of said maintenance message, on the basis of the results of a number N of preceding cycles, the occurrence rate corresponding to the average probability of occurrence, that is, to say of generation, of said maintenance message in the course of a cycle, said long-term occurrence rate being equal to the ratio between the number of occurrences of said maintenance message during the N cycles considered and the number of N cycles;

(b) determining a short-term occurrence rate of said maintenance message, at the most on the basis of the results of the last N cycles, and wherein said short-term occurrence rate Tc is calculated on the basis of the relation;

##EQU7## in which k represents the number of occurrences of the maintenance message during the last N cycles and Pn is defined on the basis of df(n) which represents, for an occurrence n, the number of cycles since the preceding occurrence n-1;

(c) comparing said short-term occurrence rate with said long-term occurrence rate; and

(d) deducing therefrom;

(i) if the short-term occurrence rate is higher than the long-term occurrence rate, that said maintenance message is representative of a real fault in the system; and

(ii) otherwise, that said maintenance message is spurious.

2. The method as claimed in claim 1, wherein Pn is calculated from the mathematical formula:

##EQU8## in which fe(n) represents the number of cycles necessary to obtain n occurrences, and a1, a2, a3 and a4 are constants.

3. A method for determining whether a maintenance message generated, during an operating cycle of a system, by a maintenance device monitoring said system, is representative of a real fault in said system or whether this maintenance message is spurious, wherein, at the end of said operating cycle, the method comprising the steps of:

(a) determining a long-term occurrence rate of said maintenance message, on the basis of the results of a number N of preceding cycles, the occurrence rate corresponding to the average probability of occurrence, that is, to say of generation, of said maintenance message in the course of a cycle, said long-term occurrence rate being a dependent function of the number k of occurrences of said maintenance message during the N cycles observed, said long-term occurrence rate T1 being defined by the relation;

##EQU9## in which a5, a6 and a7 represent constants, and wherein fe(k) represents the number of cycles necessary to obtain k occurrences;

(b) determining a short-term occurrence rate of said maintenance message at the most on the basis of the results of the last N cycles;

(c) comparing said short-term occurrence rate with said long-term occurrence rate; and

(d) deducing therefrom;

(i) if the short term occurrence rate is higher than the long-term occurrence rate, that said maintenance message is representative of a real fault in the system; and

(ii) otherwise, that said maintenance message is spurious.

4. The method as claimed in claim 3, wherein said short-term occurrence rate Tc is calculated on the basis of the relation:

##EQU10## in which k represents the number of occurrences of the maintenance message during the last N cycles and Pn is defined on the basis of df(n) which represents, for an occurrence n, the number of cycles since the preceding occurrence n-1.

5. The method as claimed in claim 4, wherein Pn is calculated from the mathematical formula:

##EQU11## in which fe(n) represents the number of cycles necessary to obtain n occurrences, and a1, a2, a3 and a4 are constants.