Neuromorphic Weight Transfer for Defective Synaptic Cells

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Solution Overview

Problem

Existing hardware-based spiking neural networks face performance degradation due to defective synaptic elements during inference processes, with current methods lacking a fundamental solution to address this issue effectively.

Innovation Solution

A weight transfer apparatus and method that builds an artificial neural network learning model considering defective synaptic cells, sets corresponding weights to 0, and transfers the rebuilt model to a neuromorphic device, thereby maintaining performance even with defective elements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If synaptic elements are used in neuromorphic devices, then computing performance is improved, but defective cells occur during manufacturing

Engineering Contradiction:
Improvecomputing performanceVSAvoiddefective cells
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The system performs preliminary actions by detecting defective synaptic cells before they affect computing performance. The weight transfer apparatus identifies defective cells and adjusts weights in advance, preventing performance degradation from occurring in the first place.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements feedback mechanisms where the weight transfer apparatus continuously monitors synaptic element performance, detects defects, and automatically adjusts weights accordingly. This closed-loop feedback ensures that defective cells are compensated for, maintaining reliable computing performance.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If existing neural network weights are transferred to hardware SNN, then inference accuracy is maintained, but defective synaptic elements cause performance degradation

Engineering Contradiction:
Improveinference accuracyVSAvoidperformance stability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The system converts the harmful effect of defective synaptic cells into a beneficial process by using the weight transfer apparatus to detect and compensate for these defects. The defects are identified and corrected through automated weight adjustment, transforming a liability into an opportunity for system optimization.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The weight transfer apparatus changes the parameter of weight values corresponding to defective synaptic cells. By modifying these weight parameters (setting them to zero or adjusting them), the system compensates for the physical defects in the hardware, maintaining inference accuracy despite the presence of faulty cells.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If redundant array methods are used to address defective elements, then manufacturing complexity increases, but defect tolerance is improved

Engineering Contradiction:
Improvedefect toleranceVSAvoidmanufacturing process
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Instead of using complex redundant array structures, the system creates a software-based copy or representation of the synaptic weight matrix. The weight transfer apparatus processes this digital copy to identify and compensate for defective cells, avoiding the need for complex hardware redundancy while achieving defect tolerance.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The weight transfer apparatus acts as an intermediary between the physical synaptic elements and the computing tasks. It mediates the interaction by detecting defective cells and adjusting weights, thereby protecting the system from the complexity of handling defective hardware directly.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentUS20230162014A1Weight transfer apparatus for neuromorphic devices and weight transfer method using the same
Publication Date: 2023.05.25 SEOUL NATIONAL UNIVERSITY R&DB FOUNDATION
  • US20230162014A1 patent drawing
  • US20230162014A1 patent drawing
  • US20230162014A1 patent drawing

AI summary

A weight transfer apparatus for a neuromorphic device includes a memory storing a weight transfer program for the neuromorphic device, and a processor configured to execute the weight transfer program. The weight transfer program builds an artificial neural network learning model, transfers a weight of the built artificial neural network learning model to the neuromorphic device, determines whether a synaptic cell included in the neuromorphic device to which the weight is transferred is defective, rebuilds the artificial neural network learning model after the artificial neural network learning model sets a weight corresponding to a defective synaptic cell to 0, and transfers a weight of the rebuilt artificial neural network learning model to the neuromorphic device.