Binarized Neural Network Circuit Eliminates Bias Term

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Solution Overview

Problem

Conventional CNNs require a bias term for accurate weight distribution adjustment, leading to increased area and power consumption due to the need for additional circuits and high bit accuracy, especially as weights become more evenly distributed during learning.

Innovation Solution

A neural network circuit device that includes a logic circuit for binary input and weight processing, a sum circuit for summing output results, a batch normalization circuit to correct variance through normalization and shifting, and an activation circuit using the sgn function, eliminating the need for a bias term by incorporating a scaling coefficient and shift value.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a bias term is used for accurate weight distribution adjustment in CNN, then recognition accuracy is improved, but area and power consumption increase due to additional circuits and high bit accuracy requirements

Engineering Contradiction:
Improverecognition accuracyVSAvoidcircuit area
Core Design Contradiction:
Measurement precisionVSArea of stationary object

Solution Approach 1:

The patent transforms the bias term from a high-precision floating-point value into a low-precision integer offset applied after batch normalization. By changing the parameter representation and applying it at a different stage (post-normalization), the circuit can use simple integer addition instead of high-precision floating-point addition, significantly reducing area and power consumption while maintaining recognition accuracy.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If a bias term is used for accurate weight distribution adjustment in CNN, then recognition accuracy is improved, but power consumption increases due to additional circuits and high bit accuracy requirements

Engineering Contradiction:
Improverecognition accuracyVSAvoidpower consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by stationary object

Solution Approach 1:

The patent changes the bias term from a high-precision floating-point parameter to a low-precision integer offset. This parameter transformation allows the use of simple integer addition circuits instead of high-precision floating-point adders, dramatically reducing power consumption while preserving the functional effect of weight distribution adjustment.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent extracts the bias functionality from the traditional pre-activation position and relocates it to post-normalization. By separating the bias application from the main computational path and applying it after batch normalization, the circuit avoids the need for high-precision bias storage and computation, reducing power consumption.

Inventive Principle:
Principle #2Taking out (Extraction)

3Area of stationary object

If binarized accuracy is used to reduce hardware complexity, then area and power consumption are reduced, but recognition accuracy deteriorates

Engineering Contradiction:
Improvecircuit areaVSAvoidrecognition accuracy
Core Design Contradiction:
Area of stationary objectVSMeasurement precision

Solution Approach 1:

The patent applies batch normalization to transform the binarized weights and activations into a distribution with zero mean and unit variance. This parameter transformation allows the use of simple binary multiplication (XNOR operations) while maintaining the statistical properties needed for accurate recognition, effectively decoupling hardware simplicity from recognition performance.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS11741348B2Neural network circuit device, neural network, neural network processing method, and neural network execution program
Publication Date: 2023.08.29 TOKYO ARTISAN INTELLIGENCE CO LTD
  • US11741348B2 patent drawing
  • US11741348B2 patent drawing
  • US11741348B2 patent drawing

AI summary

Provided are a neural network circuit device, a neural network, a neural network processing method, and a neural network execution program, each of which does not require a bias. A binarized neural network circuit includes: an input part configured to allow input of an input node which allows input of input values x1-xn (xi) (binary), and input of weights w1-wn (wi) (binary); an XNOR gate circuit configured to receive the input values x1-xn and the weights w1-wn and to take XNOR logic; a sum circuit configured to sum XNOR logical values; a batch normalization circuit configured to correct a variance due to binarization, by extending a range of normalization and shifting a center thereof; and an activating function circuit configured to convert a signal B obtained by batch-normalizing a signal Y generated by taking the sum, by means of an activating function f sgn(B).