HyDREA: Utilizing Hyperdimensional Computing for a More Robust and Efficient Machine Learning System

Today's systems rely on sending all the data to the cloud and then using complex algorithms, such as Deep Neural Networks, which require billions of parameters and many hours to train a model. In contrast, the human brain can do much of this learning effortlessly. Hyperdimensional (HD) Computing aims to mimic the behavior of the human brain by utilizing high-dimensional representations. This leads to various desirable properties that other Machine Learning (ML) algorithms lack, such as robustness to noise in the system and simple, highly parallel operations. In this article, we propose HyDREA, a HyperDimensional Computing system that is Robust, Efficient, and Accurate. We propose a Processing-in-Memory (PIM) architecture that works in a federated learning environment with challenging communication scenarios that cause errors in the transmitted data. HyDREA adaptively changes the bitwidth of the model based on the signal-to-noise ratio (SNR) of the incoming sample to maintain the accuracy of the HD model while achieving significant speedup and energy efficiency. Our PIM architecture is able to achieve a speedup of 28x and 255x better energy efficiency compared to the baseline PIM architecture for Classification and achieves 32x speed up and 289x higher energy efficiency than the baseline architecture for Clustering. HyDREA is able to achieve this by relaxing hardware parameters to gain energy efficiency and speedup while introducing computational errors. We show experimentally, HD Computing is able to handle the errors without a significant drop in accuracy due to its unique robustness property. For wireless noise, we found that HyDREA is 48x more robust to noise than other comparable ML algorithms. Our results indicate that our proposed system loses less than 1% Classification accuracy, even in scenarios with an SNR of 6.64. We additionally test the robustness of using HD Computing for Clustering applications and found that our proposed system also looses less than 1% in the mutual information score, even in scenarios with an SNR under 7 dB, which is 57x more robust to noise than K-means.