Dywave: Event-Aligned Dynamic Tokenization for Heterogeneous IoT Sensing Signals

TL;DR

Dywave introduces a wavelet-based dynamic tokenization method for IoT signals, improving accuracy, efficiency, and robustness by aligning representations with intrinsic temporal events.

Contribution

It presents a novel adaptive tokenization framework that captures semantic events in non-stationary IoT signals, outperforming existing techniques.

Findings

Outperforms state-of-the-art methods by up to 12% in accuracy.

Reduces input token lengths by up to 75%, enhancing computational efficiency.

Improves robustness to domain shifts and variable sequence lengths.

Abstract

Internet of Things (IoT) systems continuously collect heterogeneous sensing signals from ubiquitous sensors to support intelligent applications such as human activity analysis, emotion monitoring, and environmental perception. These signals are inherently non-stationary and multi-scale, posing unique challenges for standard tokenization techniques. This paper proposes Dywave, a dynamic tokenization framework for IoT sensing signals that constructs compact input representations aligned with intrinsic temporal structures and underlying physical events. Dywave leverages wavelet-based hierarchical decomposition, identifies meaningful temporal boundaries corresponding to underlying semantic events, and adaptively compresses redundant intervals while preserving temporal coherence. Extensive evaluations on five real-world IoT sensing datasets across activity recognition, stress assessment, and nearby object detection demonstrate that Dywave outperforms state-of-the-art methods by up to 12% in accuracy, while improving computational efficiency by reducing input token lengths by up to 75% across mainstream sequence models. Moreover, Dywave exhibits improved robustness to domain shifts and varying sequence lengths.