Ensemble Activation Function for Neural Network Inference

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Solution Overview

Problem

The selection of activation functions in neural networks for medical data inference is crucial but often arbitrary, affecting inference performance, and there is a need for a method that optimizes this selection to enhance performance.

Innovation Solution

The implementation of an ensemble activation function that combines multiple activation functions with mixing coefficients, applied across unit network structures to convert input vector elements to output vector elements, allowing for optimized inference data generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single activation function is selected by designer, then the neural network structure is simple, but the inference performance is limited

Engineering Contradiction:
Improveinference performanceVSAvoidactivation function structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple activation functions into a single ensemble activation function that processes inputs through parallel activation function paths. Each activation function (e.g., ReLU, sigmoid, tanh) operates on the same input, and their outputs are combined through mixing coefficients to produce the final output, thereby merging multiple functions' capabilities into one unified structure that improves inference performance while maintaining manageable complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The ensemble activation function introduces dynamic adaptability by using learnable mixing coefficients that can be optimized during training. Instead of selecting a fixed activation function, the system dynamically adjusts the contribution of each activation function based on the input data characteristics, allowing the network to adaptively select the most suitable activation behavior for different scenarios.

Inventive Principle:
Principle #15Dynamics

2Reliability

If multiple activation functions are combined, then the inference performance improves, but the device complexity increases

Engineering Contradiction:
Improveinference performanceVSAvoidactivation function structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The ensemble activation function serves multiple purposes simultaneously: it provides non-linear transformation, feature extraction, and adaptive weighting of different activation behaviors. By making the activation function structure universal and multi-functional, the patent achieves improved inference performance without proportionally increasing complexity, as the same structure handles multiple computational tasks.

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

Solution Approach 2:

The patent changes the parameters of the activation function system by introducing mixing coefficients as additional learnable parameters. Instead of changing the fundamental structure drastically, it modifies the parameter space to include weights that control the contribution of each activation function, allowing performance improvement through parameter optimization rather than structural complexity.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If designer manually selects activation function, then the implementation is simple, but the adaptability to different purposes is limited

Engineering Contradiction:
Improveactivation function selectionVSAvoidactivation function implementation
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The ensemble activation function enables the neural network to self-select the optimal activation behavior through the learnable mixing coefficients. During training, the system automatically adjusts the coefficients to optimize performance for the specific task and data type, eliminating the need for manual designer selection while maintaining ease of implementation through automated parameter optimization.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system incorporates feedback mechanisms through the training process, where the performance outcome feeds back into the optimization of mixing coefficients. This feedback loop allows the system to learn from its performance and automatically adapt the activation function composition to suit different purposes, achieving high adaptability without manual intervention.

Inventive Principle:
Principle #23Feedback

Data Source

PatentUS20230134630A1Inference apparatus, medical image diagnostic apparatus, inference method, and trained neural network generation method
Publication Date: 2023.05.04 CANON KK
  • US20230134630A1 patent drawing
  • US20230134630A1 patent drawing
  • US20230134630A1 patent drawing

AI summary

According to one embodiment, an inference apparatus includes a processing circuit configured to: obtain processing target data; and calculate inference data by applying a trained neural network to the processing target data, wherein the trained neural network includes an ensemble activation function for each of a plurality of unit network structures configured to convert an input vector element to an output vector element, the ensemble activation function being configured to execute a calculation based on a plurality of activation functions and a plurality of mixing coefficients respectively corresponding to the activation functions.