Sensor Causal DAGs for Root Cause Analysis in Noisy IoT Data

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Solution Overview

Problem

Automated root cause analysis of anomaly events in high-dimensional sensor data from IoT devices in industrial settings is hindered by the complexity and irregularities of sensor data, such as heterogeneous formats, errors, and high correlation, which existing methods fail to address effectively.

Innovation Solution

A system that preprocesses sensor data by aligning it to a unified global reference time, applying data summarization and interpolation techniques to generate meta-nodes, and builds an optimal Directed Acyclic Graph (DAG) to model causal dependencies, allowing for the determination of anomaly causes through back-tracking in the graph structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual study and identification of causal relationships among sensors is performed, then accuracy of root cause analysis is improved, but time consumption and cost increase prohibitively with growing data dimensionality

Engineering Contradiction:
Improveaccuracy of root cause analysisVSAvoidtime consumption
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces manual mechanical analysis with automated computational methods. Specifically, it uses machine learning algorithms to automatically discover causal relationships among sensors, substituting human expert analysis with algorithmic processing that scales efficiently to high-dimensional data without proportionally increasing time or cost.

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

Solution Approach 2:

The patent introduces an intermediate computational layer between raw sensor data and root cause identification. This layer includes data preprocessing modules, feature extraction algorithms, and causal inference engines that transform raw high-dimensional sensor data into meaningful causal relationships, enabling automated analysis while maintaining accuracy.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If automated root cause analysis is implemented, then productivity and scalability are improved, but handling of data irregularities and heterogeneity becomes more challenging

Engineering Contradiction:
Improveautomation capabilityVSAvoidcomplexity of data processing
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the complex data processing task into distinct modular stages: data preprocessing (handling missing values, outliers, and synchronization), feature extraction (identifying relevant sensor patterns), causal relationship discovery (building causal graphs), and root cause identification (tracing anomalies to sources). Each module handles specific aspects of data irregularities independently, making the overall system more manageable and scalable.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transforms raw sensor data into standardized parameters and features through preprocessing operations. By converting heterogeneous sensor readings into unified temporal and statistical parameters, the system simplifies subsequent causal analysis while maintaining the ability to handle diverse data types and irregularities.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If high-dimensional sensor data is analyzed in detail, then completeness of anomaly detection is improved, but computational cost and complexity increase exponentially

Engineering Contradiction:
Improvecompleteness of anomaly detectionVSAvoidcomputational cost
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent extracts only the most relevant features and causal relationships from high-dimensional sensor data rather than analyzing all dimensions equally. By identifying and focusing on key sensors and causal pathways that contribute most to anomaly detection, the system maintains high reliability while significantly reducing computational requirements through selective feature extraction and dimensionality reduction.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP3754906B1Method and system for performing automated root cause analysis of anomaly events in high-dimensional sensor data
Publication Date: 2022.12.07 PALO ALTO RESEARCH CENTER INC
  • EP3754906B1 patent drawingFigure 1A~1B
  • EP3754906B1 patent drawingFigure 2
  • EP3754906B1 patent drawingFigure 3A~3B

AI summary

One embodiment of the present invention can provide a system for identifying a root cause of an anomaly event in operation of one or more machines is provided. During operation, the system can obtain sensor data from a set of sensors associated with the one or more machines, convert the sensor data into a set of sensor states, build an optimal DAG based on the set of sensor states to model causal dependency; determining, by using the DAG, a probability of an anomaly state of a target sensor given a state of a direct neighbor sensor, and determining a root cause of the anomaly event associated with the target sensor by back-tracking the anomaly state in the DAG.