Weighted Persistence Diagram Feature Extraction

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Solution Overview

Problem

Existing methods for extracting features from time series data using topological data analysis (TDA) face challenges in distinguishing between data sets due to the removal of information with short existence times, which can lead to inaccurate feature extraction, especially in cases with high-frequency components or small amplitudes.

Innovation Solution

A method that generates quasi-attractors from time series data, performs persistent homology conversion, and adjusts weights based on the existence and appearance times of holes in the persistence diagram to generate a weighted Betti sequence, allowing for more accurate feature extraction while maintaining the influence of data with short existence times.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If data with short existence times is removed during feature extraction, then noise suppression is improved, but information loss occurs leading to reduced measurement precision

Engineering Contradiction:
Improvenoise suppressionVSAvoidfeature extraction accuracy
Core Design Contradiction:
Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

The patent applies local quality by differentiating the treatment of data points based on their local characteristics (existence time and appearance time). Instead of uniformly removing all short-duration features, the method selectively weights individual data points in the persistence diagram based on their specific temporal properties, preserving locally significant features while suppressing locally insignificant noise.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes parameters by introducing weight values that modify the influence of each data point based on its existence time and appearance time. This parameter transformation allows the system to dynamically adjust the contribution of each feature to the final Betti sequence, transforming fixed threshold-based noise removal into a flexible, parameter-driven weighting scheme that maintains precision while suppressing noise.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If all data points in the persistence diagram are treated equally, then processing simplicity is maintained, but feature differentiation capability is reduced

Engineering Contradiction:
Improveprocessing simplicityVSAvoidfeature differentiation accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent implements local quality by assigning different weight values to different data points in the persistence diagram based on their individual characteristics (existence time and appearance time). This allows the system to differentiate between significant features and noise while maintaining a relatively simple processing framework that builds upon the existing persistent homology conversion process.

Inventive Principle:
Principle #3Local quality

Data Source

PatentUS20200311587A1Method for extracting features, storage medium, and apparatus for extracting features
Publication Date: 2020.10.01 FUJITSU LTD
  • US20200311587A1 patent drawing
  • US20200311587A1 patent drawing
  • US20200311587A1 patent drawing

AI summary

A method for extracting features, the method being implemented by a computer, the method includes generating attractors from time series data having a cyclic characteristic; generating a persistence diagram by performing persistent homology conversion for the attractors; changing a degree of influence with respect to individual items of data in the persistence diagram in accordance with a time of existence or an appearance time of a hole generated by performing the persistent homology conversion; and extracting features of the time series data from the changed persistence diagram in which the degree of influence has been changed.