Neural Network Classification Vector Initialization for Unbalanced Data

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Solution Overview

Problem

Existing neural network initialization techniques fail to address the distribution of weights in classification vectors, leading to classification bias in unbalanced datasets, where classification vectors with more training samples dominate, resulting in inaccurate classifications.

Innovation Solution

The proposed solution initializes classification layers by strategically placing classification vectors with similar numbers of training samples near each other in the classification space, ensuring fair competition and reducing bias, using a method that involves counting training samples, ranking classes, and assigning them to vectors to maintain even distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If classification vectors are initialized using conventional techniques focusing on weight magnitudes, then convergence of the neural network is ensured, but classification bias occurs in unbalanced datasets where vectors with more training samples dominate

Engineering Contradiction:
ImproveconvergenceVSAvoidclassification accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent applies preliminary action by strategically initializing classification vectors before training begins. Specifically, it positions vectors corresponding to classes with fewer training samples closer to the origin in the classification space, while placing vectors for classes with more samples farther from the origin. This pre-initialization compensates for the expected dominance of larger classes during training, ensuring more balanced classification performance without affecting convergence.

Inventive Principle:
Principle #10Preliminary action

2Ease of manufacture

If classification vectors are placed uniformly in the classification space, then initialization is simple, but bias occurs when training sample distribution is unbalanced across classes

Engineering Contradiction:
Improveinitialization simplicityVSAvoidclassification accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent applies local quality by making the initialization strategy adaptive to local characteristics of each class. Instead of uniform placement, it customizes the position of each classification vector based on the specific number of training samples for that class. Classes with fewer samples receive vectors positioned closer to the origin, while classes with more samples receive vectors farther from the origin, creating locally optimized initialization that addresses the unbalanced distribution.

Inventive Principle:
Principle #3Local quality

3Ease of operation

If classification vectors for classes with different training sample counts are initialized with equal magnitude, then initialization is consistent, but dominant classes overwhelm minority classes during training

Engineering Contradiction:
Improveinitialization consistencyVSAvoidclassification performance for minority classes
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies parameter changes by modifying the magnitude parameter of classification vectors based on the training sample count for each class. Instead of using a fixed or uniform magnitude, it dynamically adjusts the magnitude of each vector's initialization according to its class's sample distribution, thereby balancing the competitive dynamics during training and improving minority class performance.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS11676034B2Initialization of classification layers in neural networks
Publication Date: 2023.06.13 THE NIELSEN CO (US) LLC
  • US11676034B2 patent drawing
  • US11676034B2 patent drawing
  • US11676034B2 patent drawing

AI summary

Example methods disclosed herein to initialize classification vectors of a neural network include ranking a plurality of classes to be represented by the classification vectors based on respective numbers of instances of training data associated with corresponding ones of the classes. Disclosed example methods also include initializing the classification vectors to span a classification space corresponding to the classes. Disclosed example methods further include assigning respective ones of the classes to corresponding ones of the classification vectors based on the ranking of the classes.