Binary Neural Network Channel Pruning by Weight Flipping Frequency

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Solution Overview

Problem

Existing pruning methods for binary neural networks (BNNs) are inadequate due to the non-trivial nature of 0s and 1s, and unstructured pruning introduces memory overhead without significant savings, while existing full-precision network pruning methods are not applicable.

Innovation Solution

A pruning method for BNNs that uses weight flipping frequency as an indicator to identify insensitive weights, reducing the network size by shrinking channels in each layer and retraining the pruned model, avoiding unstructured pruning and memory overhead.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If existing pruning methods for full-precision networks are applied to BNNs, then pruning can be performed, but the methods are inadequate because both 0s and 1s are non-trivial in BNNs and existing methods interpret 0s as trivial

Engineering Contradiction:
Improveapplicability of pruning methodVSAvoidaccuracy identification
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent changes the parameter used for identifying prunable weights from the conventional magnitude-based metric (suitable for full-precision networks where 0s are trivial) to weight flipping frequency (suitable for BNNs where both 0s and 1s are non-trivial). This parameter change allows existing pruning methodologies to be adapted to BNNs while maintaining accuracy identification reliability.

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If unstructured pruning is applied to BNNs, then weight reduction can be achieved, but memory overhead is introduced to label the prunable weights

Engineering Contradiction:
Improvenumber of weightsVSAvoidmemory overhead
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent applies structured pruning by segmenting the network into channels and groups, pruning entire channels or groups rather than individual weights. This segmentation approach achieves weight reduction while avoiding the need for per-weight labels, thereby eliminating the memory overhead associated with unstructured pruning.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces channel-wise and group-wise pruning strategies that apply different pruning ratios to different channels or groups based on their importance. This local quality approach allows selective pruning of less important channels while preserving important ones, achieving compression without requiring detailed per-weight labels.

Inventive Principle:
Principle #3Local quality

3Quantity of substance

If more weights are pruned to reduce network size, then compression ratio increases, but accuracy maintenance becomes more difficult

Engineering Contradiction:
Improvenetwork sizeVSAvoidaccuracy
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent employs iterative pruning with accuracy feedback, where weights are pruned in multiple stages and the network accuracy is evaluated after each stage. The pruning process adjusts the pruning ratio based on accuracy feedback, allowing aggressive pruning when accuracy is maintained and conservative pruning when accuracy degrades. This feedback mechanism enables achieving high compression ratios while maintaining acceptable accuracy levels.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent performs preliminary identification of important channels and groups using weight flipping frequency analysis before actual pruning. This preliminary action allows the method to prioritize which channels to prune first, ensuring that less important channels are removed while preserving important ones, thereby maintaining accuracy even with significant weight reduction.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS12387101B2Systems and methods for pruning binary neural networks guided by weight flipping frequency
Publication Date: 2025.08.12 THE ARIZONA BOARD OF REGENTS ON BEHALF OF THE UNIV OF ARIZONA
  • US12387101B2 patent drawing
  • US12387101B2 patent drawing
  • US12387101B2 patent drawing

AI summary

Various embodiments of a system and method for pruning binary neural networks by analyzing weight flipping frequency and pruning the binary neural network based on the weight flipping frequency associated with each channel of the binary neural network are disclosed herein.