Ensemble Voting Classifier Threshold Adjustment

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Solution Overview

Problem

Existing ensemble voting classifiers face challenges in setting voting thresholds to balance sensitivity and specificity, leading to issues with false positive classifications and over-fitting to training data.

Innovation Solution

A system that adjusts the voting thresholds of each classifier based on vote contributions during training, allowing for increased specificity without impacting sensitivity, using a threshold table and iterative adjustment methods to optimize threshold settings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If individually set voting thresholds are used for each classifier to meet training set requirements, then voting accuracy improves, but the method cannot control both sensitivity and specificity simultaneously

Engineering Contradiction:
Improvevoting accuracyVSAvoidcontrol over sensitivity and specificity
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent changes the parameter representation from fixed thresholds to threshold indices that can be adjusted independently for each classifier. This allows systematic control of sensitivity and specificity by modifying threshold values based on desired performance characteristics, resolving the contradiction between accuracy and adaptability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces dynamic threshold adjustment where thresholds are not fixed but can be modified based on sensitivity-specificity requirements. The system allows flexible tuning of classifier thresholds to meet different operational requirements, transforming a static system into a dynamic one that adapts to various performance needs.

Inventive Principle:
Principle #15Dynamics

2Stability of the object's composition

If same thresholds are applied to production items as in training, then consistency is maintained, but over-fitting to training data occurs reducing generalization

Engineering Contradiction:
Improvethreshold consistencyVSAvoidgeneralization to production data
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent performs preliminary threshold optimization on training data to establish threshold indices that achieve desired sensitivity and specificity. By pre-adjusting thresholds based on training set analysis, the system prepares optimal settings that generalize better to production data while maintaining consistency through the threshold index mechanism.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses feedback from training set performance analysis to adjust threshold indices. The system analyzes voting patterns and threshold contributions during training, then modifies thresholds accordingly to improve generalization. This feedback loop ensures that thresholds are optimized based on actual performance rather than assumed consistency.

Inventive Principle:
Principle #23Feedback

3Productivity

If genetic optimization is applied directly to voting thresholds, then optimization is attempted, but acceptable results are not yielded

Engineering Contradiction:
Improveoptimization efficiencyVSAvoidthreshold optimization accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent segments the threshold optimization problem by introducing threshold indices that decouple the optimization of individual classifier thresholds from the overall ensemble performance. This segmentation allows systematic adjustment of each classifier's contribution without requiring complex genetic optimization, improving both efficiency and accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces threshold indices as intermediaries between raw classifier outputs and final voting decisions. These indices serve as a mediating layer that simplifies the optimization process, allowing direct control over classifier contributions without the complexity of direct genetic optimization on threshold values.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Device complexity

If mean of output scores is used as final classification score, then simple combination is achieved, but sensitivity to calibration distribution differences reduces accuracy

Engineering Contradiction:
Improvecombination simplicityVSAvoidprediction accuracy under distribution differences
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent applies local quality by allowing each classifier to have its own threshold index tailored to its specific characteristics and calibration. Instead of a uniform mean-based approach, each classifier's output is adjusted locally based on its threshold index, accounting for distribution differences while maintaining the simplicity of ensemble combination.

Inventive Principle:
Principle #3Local quality

Data Source

PatentUS20220284243A1Ensemble voting classifiers using adjusted thresholds
Publication Date: 2022.09.08 INTERNATIONAL BUSINESS MACHINE CORPORATION
  • US20220284243A1 patent drawing
  • US20220284243A1 patent drawing
  • US20220284243A1 patent drawing

AI summary

An example system includes a processor to receive training data used to train an ensemble voting classifier. For each classifier in the ensemble voting classifier, the processor can also set a classification score of a positive training item as a threshold. The processor can further adjust a threshold of at least one of the classifiers based on an analysis of a vote contribution of each classifier on the votes on the training data. The threshold of the at least one of the classifiers is adjusted to increase a voting specificity without impacting sensitivity with respect to the training data.