Causal Abnormality Estimation Using Normal OT Data

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Solution Overview

Problem

Existing abnormality detection and diagnostic systems fail to accurately identify causal abnormality factors in OT systems, as they rely on correlation between data points rather than causal relationships, and require collection of abnormal data, which is time-consuming and inefficient.

Innovation Solution

An estimation apparatus comprising a correlation index estimation unit, an abnormality degree calculation unit, and a causal effect estimation unit that estimates correlation index information, abnormality degree, and causal effect to identify causal abnormality factors without needing abnormal data, using machine learning techniques like neural networks and probabilistic models.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If correlation-based abnormality detection is used, then abnormality detection capability is provided, but causal abnormality factor cannot be detected

Engineering Contradiction:
Improveabnormality detection accuracyVSAvoidcausal relationship information
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent replaces traditional correlation-based statistical methods with a neural network-based causal inference system. The neural network learns causal relationships from normal operation data alone, substituting the mechanical correlation calculation approach with an intelligent system that can identify causal abnormality factors without requiring abnormal data collection.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If abnormal data collection is performed to specify abnormality factors, then known abnormality factors can be specified, but time and effort are consumed

Engineering Contradiction:
Improveabnormality factor specification accuracyVSAvoiddata collection time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent performs preliminary learning during the normal operation phase, where the neural network is trained to recognize causal relationships between variables. This preliminary action enables the system to immediately identify causal abnormality factors when abnormalities occur, without requiring time-consuming abnormal data collection and processing.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses normal operation data to train itself and build the causal relationship model. The neural network serves itself by learning from readily available normal data, eliminating the need for external abnormal data collection efforts and making the system self-sufficient in identifying causal factors.

Inventive Principle:
Principle #25Self-service

3Ease of operation

If correlation-based abnormality determination is used, then abnormality detection is simplified, but causal abnormality factor that does not directly contribute cannot be specified

Engineering Contradiction:
Improveabnormality determination simplicityVSAvoidcausal factor identification accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent substitutes the simple correlation calculation mechanism with a neural network-based causal inference system. While the neural network adds computational complexity, it automatically learns causal relationships from data, providing both simplicity in operation (automatic identification) and precision in causal factor detection without requiring manual analysis.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS11983072B2Estimation apparatus, estimation method, and computer-readable storage medium
Publication Date: 2024.05.14 NEC CORP
  • US11983072B2 patent drawing
  • US11983072B2 patent drawing
  • US11983072B2 patent drawing

AI summary

An estimation apparatus 1 includes: a correlation index estimation unit 2 configured to receive a variable output by a component 21 as an input, and estimate correlation index information indicating a range that a value of the variable and a correlation can take after a predetermined time, at a normal time; an abnormality degree calculation unit 3 configured to calculate an abnormality degree using the correlation index information; and a causal effect estimation unit 4 configured to estimate a causal effect expressing an index indicating that an abnormality propagates to a variable output by the component 21.