Adaptive Asymmetric Loss Function for Positive Unlabeled Learning

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Solution Overview

Problem

Current positive unlabeled learning algorithms for deep neural networks require significant labeled data and assume known class priors, limiting their effectiveness in image classification tasks, especially when only positive and unlabeled images are available for training.

Innovation Solution

The system employs an adaptive asymmetric loss function paired with a simple linear transform, extending the Modified Logistic Regression algorithm into the deep learning domain, allowing for near supervised classification accuracy with minimal labeled data without requiring class prior estimates, using an adaptive asymmetric loss function that learns the label frequency during training.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If traditional semi-supervised learning or positive unlabeled learning algorithms are used, then classification models can be trained with limited labeled data, but they require significant labeled data and assume known class priors, reducing effectiveness

Engineering Contradiction:
Improvelabeled data quantityVSAvoidclassification accuracy
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent changes the parameter of loss function asymmetry to resolve the contradiction. By introducing an asymmetric loss function that penalizes misclassification of positive samples differently than negative samples, and dynamically adjusting the asymmetry parameter based on label frequency estimates, the system achieves reliable classification with minimal labeled data without requiring assumptions about class priors

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies self-service by enabling the model to learn and adjust its own parameters during training. The adaptive asymmetric loss function automatically estimates label frequency and adjusts the asymmetry parameter without external intervention, allowing the system to optimize its own performance with limited labeled data while maintaining reliability

Inventive Principle:
Principle #25Self-service

2Quantity of substance

If positive unlabeled learning algorithms are used with minimal labeled data, then data efficiency improves, but performance degrades without known class priors

Engineering Contradiction:
Improvelabeled data quantityVSAvoidclassification precision
Core Design Contradiction:
Quantity of substanceVSMeasurement precision

Solution Approach 1:

The patent implements feedback mechanisms where the asymmetric loss function continuously monitors training performance and adjusts the asymmetry parameter based on estimated label frequency. This feedback loop enables the system to maintain high classification precision with minimal labeled data by adaptively responding to the actual data distribution rather than relying on predetermined class prior assumptions

Inventive Principle:
Principle #23Feedback

3Reliability

If asymmetric loss functions are used to handle imbalanced data, then classification performance improves for minority classes, but training complexity increases

Engineering Contradiction:
Improveclassification reliabilityVSAvoidtraining complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies dynamics by making the loss function asymmetric parameter adaptive rather than fixed. The asymmetry parameter dynamically adjusts during training based on estimated label frequency, allowing the system to handle imbalanced data effectively while keeping the training process manageable. This dynamic adjustment eliminates the need for manual tuning of asymmetry parameters and reduces overall training complexity

Inventive Principle:
Principle #15Dynamics

Data Source

PatentUS20240249147A1Systems and methods for positive unlabeled learning using an adaptive asymmetric loss function
Publication Date: 2024.07.25 THE ARIZONA BOARD OF REGENTS ON BEHALF OF THE UNIV OF ARIZONA
  • US20240249147A1 patent drawing
  • US20240249147A1 patent drawing
  • US20240249147A1 patent drawing

AI summary

A system for Positive and Unlabeled (PU) learning is tailored specifically for a deep learning framework. The system incorporates an adaptive asymmetric loss function based on Modified Logistic Regression paired with a simple linear transform of an output. When only positive and unlabeled images are available for training, the system results in an inductive classifier where no estimate of the class prior is required.