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Evaluation of a Smartphone-based Human Activity Recognition System in a Daily Living Environment
Published on: December 11, 2015
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Multi-Feature Unsupervised Domain Adaptation (M-FUDA) Applied to Cross Unaligned Domain-Specific Distributions in
1School of Computer Science, University of St. Andrews, St. Andrews KY16 9SX, UK.
Sensors (Basel, Switzerland)
|April 28, 2025
Summary
This study introduces an unsupervised method to improve Wi-Fi-based human activity recognition (HAR) across different users and environments. The technique enhances privacy-preserving sensing by adapting to new conditions without retraining.
Area of Science:
- Computer Science
- Electrical Engineering
- Signal Processing
Background:
- Human-computer interaction (HCI) relies on human activity recognition (HAR) for innovation.
- Traditional HAR methods raise privacy concerns due to infrastructure and user cooperation needs.
- Wi-Fi sensing using channel state information (CSI) offers privacy-preserving, device-free HAR but faces challenges with new users, environments, and scalability.
Purpose of the Study:
- To develop an unsupervised multi-source domain adaptation technique for robust HAR.
- To address limitations of existing Wi-Fi-based HAR systems in cross-domain scenarios.
- To enhance the adaptability and scalability of device-free sensing.
Main Methods:
- Proposed an unsupervised multi-source domain adaptation technique.
- Aligned diverse data distributions with target domain variations (new users, environments, atmospheric conditions).
- Utilized a preprocessing module to convert CSI data into image-like formats for analysis.
Main Results:
- Achieved significant improvements over baseline methods in cross-domain HAR tasks.
- Demonstrated an average micro-F1 score of 81% for cross-user tasks.
- Showcased 76% for cross-user and cross-environment, and 73% for cross-atmospheric tasks.
Conclusions:
- The proposed method effectively enhances system adaptability for Wi-Fi-based HAR.
- The approach is suitable for scalable, device-free sensing in realistic cross-domain scenarios.
- This technique overcomes limitations related to unseen users, new environments, and varying atmospheric conditions.

