ScaleHD: Robust Brain-Inspired Hyperdimensional Computing via Adapative Scaling

Brain-inspired hyperdimensional computing (HDC) has demonstrated promising capability in various cognition tasks such as robotics, bio-medical signal analysis, and natural language processing. Compared to deep neural networks, HDC models show advantages such as light-weight model and one/few-shot learning capabilities, making it a promising alternative paradigm to traditional resource-demanding deep learning models particularly in edge devices with limited resources. Despite the growing popularity of HDC, the robustness of HDC models and the approaches to enhance HDC robustness has not been systematically analyzed and sufficiently examined. HDC relies on high-dimensional numerical vectors referred to as hypervectors (HV) to perform cognition tasks and the values inside the HVs are critical to the robustness of an HDC model. We propose ScaleHD, an adaptive scaling method that scales the value of HVs in the associative memory of an HDC model to enhance the robustness of HDC models. We propose three different modes of ScaleHD including Global-ScaleHD, Class-ScaleHD, and (Class + Clip)-ScaleHD which are based on different adaptive scaling strategies. Results show that ScaleHD is able to enhance HDC robustness against memory errors up to 10, 000X. Moreover, we leverage the enhanced HDC robustness in exchange for energy saving via voltage scaling method. Experimental results show that ScaleHD can reduce energy consumption on HDC memory system up to 72.2% with less than 1% accuracy loss.