SLAYER: Spike Layer Error Reassignment in Time

TL;DR

SLAYER method addresses non-differentiability in SNNs, achieving state-of-the-art performance on MNIST and other datasets.

cs.NE 🔴 Advanced 2018-09-05 5 views
Sumit Bam Shrestha Garrick Orchard
Spiking Neural Networks Backpropagation Neural Computation Low Power Temporal Dependency

Key Findings

Methodology

The SLAYER method resolves the non-differentiability issue in spiking neural networks using a temporal credit assignment strategy. It allows simultaneous learning of synaptic weights and axonal delays, supporting both fully connected and convolutional neural network architectures in a GPU-accelerated software implementation.

Key Results

  • On the MNIST dataset, the SLAYER method achieved a classification accuracy of 99.36%, surpassing other SNN learning methods.
  • On the NMNIST dataset, SLAYER achieved an accuracy of 99.20%, significantly outperforming existing methods.
  • On the DVS Gesture dataset, SLAYER achieved an accuracy of 93.64%, outperforming the TrueNorth method.

Significance

The SLAYER method is significant in the field of spiking neural networks as it addresses the non-differentiability of the spike function and achieves state-of-the-art performance on multiple datasets. This method offers new possibilities for low-power neural computation, especially in neuromorphic hardware applications.

Technical Contribution

The technical contribution of the SLAYER method lies in its unique error backpropagation mechanism that handles the temporal dependency and non-differentiability issues in spiking neurons. It not only improves SNN performance but also opens new engineering possibilities for future neuromorphic computing.

Novelty

SLAYER is the first general method to reassign spike layer errors in time. Its innovation lies in simultaneously learning synaptic weights and axonal delays, achieving state-of-the-art performance across multiple datasets.

Limitations

  • SLAYER may face high computational costs when handling larger datasets.
  • The method may require longer training times in certain scenarios.

Future Work

Future research directions include optimizing SLAYER's computational efficiency, exploring its application on larger datasets, and implementing it on neuromorphic hardware.

AI Executive Summary

Spiking Neural Networks (SNNs) are gaining attention for their low-power characteristics, but the non-differentiability of the spike function limits the application of traditional backpropagation algorithms. Existing methods often focus on single neurons or approximate derivatives to train multi-layer networks.

The SLAYER method addresses the non-differentiability issue in SNNs with a temporal credit assignment strategy. This method allows simultaneous learning of synaptic weights and axonal delays, supported by a GPU-accelerated software implementation for both fully connected and convolutional neural network architectures. Experimental results show that SLAYER achieves state-of-the-art performance on datasets like MNIST, NMNIST, and DVS Gesture.

The success of the SLAYER method offers new possibilities for low-power neural computation, particularly in neuromorphic hardware applications. However, the method may face high computational costs when handling larger datasets, and future research will focus on optimizing its computational efficiency and implementing it on neuromorphic hardware.

Deep Analysis

Background

Spiking Neural Networks (SNNs) have gained attention for their biological plausibility and low-power characteristics. Unlike traditional Artificial Neural Networks (ANNs), SNNs use spiking neurons as computational units, which have memory and communicate through voltage spikes. However, the non-differentiability of the spike function limits the application of traditional backpropagation algorithms.

Core Problem

The core problem in spiking neural networks is the non-differentiability of the spike function, which prevents the direct application of traditional error backpropagation algorithms. Additionally, the temporal dependency of SNNs increases the complexity of training.

Innovation

The core innovation of the SLAYER method lies in its temporal credit assignment strategy, which allows for the reassignment of spike layer errors in time. This method enables simultaneous learning of synaptic weights and axonal delays, achieving state-of-the-art performance across multiple datasets.

Methodology

  • �� The SLAYER method resolves the non-differentiability issue in spiking neural networks using a temporal credit assignment strategy.
  • �� It allows simultaneous learning of synaptic weights and axonal delays.
  • �� The method supports both fully connected and convolutional neural network architectures in a GPU-accelerated software implementation.

Experiments

The experimental design includes testing the performance of the SLAYER method on datasets such as MNIST, NMNIST, and DVS Gesture. Standard training and testing splits are used, and a spike counting strategy is employed for classification.

Results

The SLAYER method achieved a classification accuracy of 99.36% on the MNIST dataset, 99.20% on the NMNIST dataset, and 93.64% on the DVS Gesture dataset, all surpassing existing spiking neural network learning methods.

Applications

The SLAYER method can be directly applied to low-power neural computation, especially in neuromorphic hardware applications. Its excellent performance across multiple datasets indicates its broad potential in fields such as visual recognition and action recognition.

Limitations & Outlook

The SLAYER method may face high computational costs when handling larger datasets. Additionally, the method may require longer training times in certain scenarios. Future research will focus on optimizing its computational efficiency and implementing it on neuromorphic hardware.

Plain Language Accessible to non-experts

Imagine a factory where traditional artificial neural networks are like assembly lines, with each worker focusing only on their current task. Spiking neural networks are like a smart factory where workers need to remember previous steps and make decisions based on that information. The SLAYER method is like an intelligent scheduling system that reallocates tasks over time, ensuring each worker can effectively complete their work.

ELI14 Explained like you're 14

Imagine you're playing a complex game where characters need to make decisions based on past experiences. Spiking neural networks are like these characters, and the SLAYER method is like a super-smart game engine that helps characters learn and adapt to the challenges in the game!

Glossary

Spiking Neural Network

A type of neural network that uses spiking neurons as computational units, known for biological plausibility and low power consumption.

Used in this paper for low-power neural computation research.

Backpropagation

An algorithm used to train neural networks by calculating the gradient of the error to update network weights.

The reason traditional methods cannot be directly applied to SNNs.

Temporal Credit Assignment

A method for redistributing errors over time, addressing the non-differentiability issue in spiking neural networks.

The core mechanism of the SLAYER method.

Axonal Delays

The delay in signal transmission along axons, affecting the temporal dependency of neural networks.

Parameters learned simultaneously in the SLAYER method.

Spike Function

The activation function of spiking neurons, whose non-differentiability limits the application of traditional backpropagation algorithms.

The core problem addressed by the SLAYER method.

Open Questions Unanswered questions from this research

  • 1 How can the SLAYER method be effectively applied to larger datasets?
  • 2 What challenges does the implementation of the SLAYER method on neuromorphic hardware face?

Applications

Immediate Applications

Low-Power Neural Computation

The SLAYER method can be used to develop low-power neural computation systems suitable for mobile devices and embedded systems.

Long-term Vision

Neuromorphic Hardware Applications

The SLAYER method holds promise for efficient neural computation on neuromorphic hardware, driving the development of intelligent devices.

Abstract

Configuring deep Spiking Neural Networks (SNNs) is an exciting research avenue for low power spike event based computation. However, the spike generation function is non-differentiable and therefore not directly compatible with the standard error backpropagation algorithm. In this paper, we introduce a new general backpropagation mechanism for learning synaptic weights and axonal delays which overcomes the problem of non-differentiability of the spike function and uses a temporal credit assignment policy for backpropagating error to preceding layers. We describe and release a GPU accelerated software implementation of our method which allows training both fully connected and convolutional neural network (CNN) architectures. Using our software, we compare our method against existing SNN based learning approaches and standard ANN to SNN conversion techniques and show that our method achieves state of the art performance for an SNN on the MNIST, NMNIST, DVS Gesture, and TIDIGITS datasets.

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