Graph-Enhanced Low-Resource ECG Representation Learning for Emotion Recognition Based on Wearable Internet of Things

Internet of Things (IoT) devices like wearable devices have enabled quick monitoring of electrocardiogram (ECG) signals with lower resources than multielectrode ECG devices, opening up development opportunities for sustainable ECG-based emotion recognition. However, existing methods that rely on predesigned features extracted from single-lead ECG signals cannot automatically extract effective features from the original ECG signal collected by IoT devices. To address this limitation, we propose a novel approach leveraging signal transformation and graph representation learning for ECG-based emotion recognition. The signal graph learning process can be divided into local subgraph learning for ECG representation learning and signal enhancement graph to derive the graph-enhanced representation. We employ a designed loss function by calculating cosine similarity to extract an effective representation of the original signal from the transformed signal in the local subgraph learning. Additionally, we utilize a graph convolution model based on the signal enhancement graph to obtain a graph-enhanced representation of the ECG signal. The method incorporates six signal transformations and constructs a self-signal transformation graph. For emotion recognition, we design a classification network comprising convolutional neural networks (CNNs) and long short-term memory (LSTM) networks. Experiments on public data sets show the superiority of our method among other baselines. Ablation studies are conducted to verify the performance.