Enhancing the Transformer Model with a Convolutional Feature Extractor Block and Vector-Based Relative Position Embedding for Human Activity Recognition
The Transformer model has received significant attention in Human Activity Recognition (HAR) due to its self-attention mechanism that captures long dependencies in time series. However, for Inertial Measurement Unit (IMU) sensor time-series signals, the Transformer model does not effectively utilize...
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MDPI AG
2025-01-01
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author | Xin Guo Young Kim Xueli Ning Se Dong Min |
author_facet | Xin Guo Young Kim Xueli Ning Se Dong Min |
author_sort | Xin Guo |
collection | DOAJ |
description | The Transformer model has received significant attention in Human Activity Recognition (HAR) due to its self-attention mechanism that captures long dependencies in time series. However, for Inertial Measurement Unit (IMU) sensor time-series signals, the Transformer model does not effectively utilize the a priori information of strong complex temporal correlations. Therefore, we proposed using multi-layer convolutional layers as a Convolutional Feature Extractor Block (CFEB). CFEB enables the Transformer model to leverage both local and global time series features for activity classification. Meanwhile, the absolute position embedding (APE) in existing Transformer models cannot accurately represent the distance relationship between individuals at different time points. To further explore positional correlations in temporal signals, this paper introduces the Vector-based Relative Position Embedding (vRPE), aiming to provide more relative temporal position information within sensor signals for the Transformer model. Combining these innovations, we conduct extensive experiments on three HAR benchmark datasets: KU-HAR, UniMiB SHAR, and USC-HAD. Experimental results demonstrate that our proposed enhancement scheme substantially elevates the performance of the Transformer model in HAR. |
format | Article |
id | doaj-art-64a8adb1dbce44e78b33e6294d942ecc |
institution | Kabale University |
issn | 1424-8220 |
language | English |
publishDate | 2025-01-01 |
publisher | MDPI AG |
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series | Sensors |
spelling | doaj-art-64a8adb1dbce44e78b33e6294d942ecc2025-01-24T13:48:25ZengMDPI AGSensors1424-82202025-01-0125230110.3390/s25020301Enhancing the Transformer Model with a Convolutional Feature Extractor Block and Vector-Based Relative Position Embedding for Human Activity RecognitionXin Guo0Young Kim1Xueli Ning2Se Dong Min3Department of Software Convergence, Soonchunhyang University, Asan 31538, Republic of KoreaDepartment of Software Convergence, Soonchunhyang University, Asan 31538, Republic of KoreaDepartment of Software Convergence, Soonchunhyang University, Asan 31538, Republic of KoreaDepartment of Software Convergence, Soonchunhyang University, Asan 31538, Republic of KoreaThe Transformer model has received significant attention in Human Activity Recognition (HAR) due to its self-attention mechanism that captures long dependencies in time series. However, for Inertial Measurement Unit (IMU) sensor time-series signals, the Transformer model does not effectively utilize the a priori information of strong complex temporal correlations. Therefore, we proposed using multi-layer convolutional layers as a Convolutional Feature Extractor Block (CFEB). CFEB enables the Transformer model to leverage both local and global time series features for activity classification. Meanwhile, the absolute position embedding (APE) in existing Transformer models cannot accurately represent the distance relationship between individuals at different time points. To further explore positional correlations in temporal signals, this paper introduces the Vector-based Relative Position Embedding (vRPE), aiming to provide more relative temporal position information within sensor signals for the Transformer model. Combining these innovations, we conduct extensive experiments on three HAR benchmark datasets: KU-HAR, UniMiB SHAR, and USC-HAD. Experimental results demonstrate that our proposed enhancement scheme substantially elevates the performance of the Transformer model in HAR.https://www.mdpi.com/1424-8220/25/2/301human activity recognitioninertial measurement units (IMUs)transformer modelrelative position embeddingconvolutional neural networks (CNNs)time series signal |
spellingShingle | Xin Guo Young Kim Xueli Ning Se Dong Min Enhancing the Transformer Model with a Convolutional Feature Extractor Block and Vector-Based Relative Position Embedding for Human Activity Recognition Sensors human activity recognition inertial measurement units (IMUs) transformer model relative position embedding convolutional neural networks (CNNs) time series signal |
title | Enhancing the Transformer Model with a Convolutional Feature Extractor Block and Vector-Based Relative Position Embedding for Human Activity Recognition |
title_full | Enhancing the Transformer Model with a Convolutional Feature Extractor Block and Vector-Based Relative Position Embedding for Human Activity Recognition |
title_fullStr | Enhancing the Transformer Model with a Convolutional Feature Extractor Block and Vector-Based Relative Position Embedding for Human Activity Recognition |
title_full_unstemmed | Enhancing the Transformer Model with a Convolutional Feature Extractor Block and Vector-Based Relative Position Embedding for Human Activity Recognition |
title_short | Enhancing the Transformer Model with a Convolutional Feature Extractor Block and Vector-Based Relative Position Embedding for Human Activity Recognition |
title_sort | enhancing the transformer model with a convolutional feature extractor block and vector based relative position embedding for human activity recognition |
topic | human activity recognition inertial measurement units (IMUs) transformer model relative position embedding convolutional neural networks (CNNs) time series signal |
url | https://www.mdpi.com/1424-8220/25/2/301 |
work_keys_str_mv | AT xinguo enhancingthetransformermodelwithaconvolutionalfeatureextractorblockandvectorbasedrelativepositionembeddingforhumanactivityrecognition AT youngkim enhancingthetransformermodelwithaconvolutionalfeatureextractorblockandvectorbasedrelativepositionembeddingforhumanactivityrecognition AT xuelining enhancingthetransformermodelwithaconvolutionalfeatureextractorblockandvectorbasedrelativepositionembeddingforhumanactivityrecognition AT sedongmin enhancingthetransformermodelwithaconvolutionalfeatureextractorblockandvectorbasedrelativepositionembeddingforhumanactivityrecognition |