One-Class Classifier Anomaly Evaluation for Machine Condition Monitoring

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Solution Overview

Problem

One-class classifiers in machine condition monitoring systems provide limited information, making it difficult to assess the severity of anomalies detected, as they only indicate whether a measurement is within or outside the normal operating range, without providing insights into how different the anomaly is from the normal distribution.

Innovation Solution

The method evaluates anomalies by projecting them onto the closest boundary of the decision region and calculating the distance from the anomaly to this boundary, using techniques like Euclidean distance and k-mean algorithms to determine the extent of deviation from the normal operating range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a one-class classifier is used to detect anomalies, then anomaly detection capability is provided, but the information provided is too limited for sophisticated fault diagnostics

Engineering Contradiction:
Improveanomaly detection capabilityVSAvoidinformation completeness for fault diagnostics
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The patent transforms the one-class classifier output from a single binary decision (anomaly/normal) into multiple dimensions by calculating distances to different boundaries of the decision region. This dimensional expansion provides richer information about anomaly characteristics, enabling sophisticated fault diagnostics while maintaining the simplicity of the one-class classifier approach.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of operation

If only binary decision output is used from one-class classifier, then classification simplicity is maintained, but the ability to evaluate anomaly severity is lost

Engineering Contradiction:
Improveclassification simplicityVSAvoidanomaly severity evaluation
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent segments the anomaly evaluation process by calculating distances to multiple different boundaries of the decision region. Each boundary represents a different aspect of anomaly severity, allowing the system to maintain simple binary classification while providing detailed severity evaluation through multiple distance measurements.

Inventive Principle:
Principle #1Segmentation

3Measurement precision

If distance calculation to decision region boundary is added, then anomaly evaluation capability is improved, but computational complexity increases

Engineering Contradiction:
Improveanomaly evaluation capabilityVSAvoidcomputational complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent performs preliminary action by pre-establishing the decision region boundaries during the training phase. This allows the system to maintain simple binary classification while providing detailed severity evaluation through multiple distance measurements, without adding significant computational complexity during real-time operation.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS7930122B2Evaluating anomaly for one-class classifiers in machine condition monitoring
Publication Date: 2011.04.19 SIEMENS AG
  • US7930122B2 patent drawing
  • US7930122B2 patent drawing
  • US7930122B2 patent drawing

AI summary

A method for monitoring machine conditions provides additional information using a one-class classifier in which an evaluation function is learned. In the method, a distance is determined from an anomaly measurement x to a boundary of a region R1 containing all acceptable measurements. The distance is used as a measure of the extent of the anomaly. The distance is found by searching along a line from the anomaly to a closest acceptable measurement within the region R1.