Sequential Ensemble Model Training for Open Set Diversity

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Solution Overview

Problem

Traditional machine learning ensembles face challenges in achieving effective diversity, particularly in open-set problems, where the quality and accuracy of the ensemble degrade due to the trade-off between data fidelity and decorrelation components in existing loss functions.

Innovation Solution

The approach involves co-training or sequentially training machine learning models to focus on decorrelating negative results by encouraging inter-model disagreement on incorrect classes, using a combining function that merges probability vectors to enhance ensemble diversity without the trade-off, and employing feature engineering to ensure each model learns distinct features.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional independent training with different training sets is used to achieve diversity, then model diversity is improved, but accuracy on open-set problems deteriorates due to the trade-off between data fidelity and decorrelation

Engineering Contradiction:
Improveensemble diversityVSAvoidaccuracy on open-set problems
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent applies preliminary action by pre-processing training data into positive samples (from the training distribution) and negative samples (from out-of-distribution data) before training begins. This allows models to be explicitly exposed to both in-distribution and out-of-distribution examples during training, preparing them to handle open-set problems better while maintaining diversity through different sample assignments across ensemble members.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements local quality by assigning different roles to different models in the ensemble - some models focus more on positive samples while others focus more on negative samples. This is achieved through the loss function that combines data fidelity (for positive samples) and decorrelation (for negative samples) components with different weighting, allowing each model to develop specialized expertise while contributing to overall ensemble diversity.

Inventive Principle:
Principle #3Local quality

2Reliability

If decorrelation components are added to loss functions to promote diversity, then ensemble diversity is improved, but the trade-off causes accuracy degradation on in-distribution data

Engineering Contradiction:
Improveensemble diversityVSAvoidaccuracy on in-distribution data
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent applies segmentation by dividing the training data into two distinct segments: positive samples (in-distribution) and negative samples (out-of-distribution). The loss function is also segmented, with the data fidelity component operating on positive samples and the decorrelation component operating on negative samples. This segmentation allows diversity to be promoted on negative samples without compromising accuracy on positive samples.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent extracts the decorrelation objective from the overall training process and applies it specifically to negative samples rather than applying it uniformly to all samples. By taking out the decorrelation component and restricting it to negative samples only, the patent eliminates the trade-off that would otherwise force a compromise between accuracy and diversity across all data.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If models are trained to disagree on incorrect classes, then reliability for open-set detection is improved, but complexity of the training process increases

Engineering Contradiction:
Improveopen-set detection reliabilityVSAvoidtraining process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements universality by designing a single loss function that simultaneously achieves multiple objectives: maintaining accuracy on in-distribution data through the data fidelity component, promoting diversity on out-of-distribution data through the decorrelation component, and enabling open-set detection. This multi-functional loss function approach consolidates what would otherwise require multiple separate training processes into one unified training procedure.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentUS11526693B1Sequential ensemble model training for open sets
Publication Date: 2022.12.13 AMAZON TECH INC
  • US11526693B1 patent drawing
  • US11526693B1 patent drawing
  • US11526693B1 patent drawing

AI summary

Disclosed are systems and method for training an ensemble of machine learning models with a focus on feature engineering. For example, the training of the models encourages each machine learning model of the ensemble to rely on a different set of input features from the training data samples used to train the machine learning models of the ensemble. However, instead of telling each model explicitly which features to learn, in accordance with the disclosed implementations, ML models of the ensemble may be trained sequentially, with each new model trained to disregard input features learned by previously trained ML models of the ensemble and learn based on other features included in the training data samples.