scholarly journals A GAN‐based data augmentation method for human activity recognition via the caching ability

2020 ◽  
Author(s):  
Junhao Shi ◽  
Decheng Zuo ◽  
Zhan Zhang
Keyword(s):  
Activity Recognition ◽  
Human Activity ◽  
Data Augmentation ◽  
Human Activity Recognition

scholarly journals Data Augmentation vs. Domain Adaptation—A Case Study in Human Activity Recognition

Technologies ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 55
Author(s):  
Evaggelos Spyrou ◽  
Eirini Mathe ◽  
Georgios Pikramenos ◽  
Konstantinos Kechagias ◽  
Phivos Mylonas
Keyword(s):  
Activity Recognition ◽  
Human Activity ◽  
Data Augmentation ◽  
Domain Adaptation ◽  
Recognition Task ◽  
Human Activity Recognition ◽  
Video Data ◽  
Training Dataset ◽  
Data Systems ◽  
Big Data Systems

Recent advances in big data systems and databases have made it possible to gather raw unlabeled data at unprecedented rates. However, labeling such data constitutes a costly and timely process. This is especially true for video data, and in particular for human activity recognition (HAR) tasks. For this reason, methods for reducing the need of labeled data for HAR applications have drawn significant attention from the research community. In particular, two popular approaches developed to address the above issue are data augmentation and domain adaptation. The former attempts to leverage problem-specific, hand-crafted data synthesizers to augment the training dataset with artificial labeled data instances. The latter attempts to extract knowledge from distinct but related supervised learning tasks for which labeled data is more abundant than the problem at hand. Both methods have been extensively studied and used successfully on various tasks, but a comprehensive comparison of the two has not been carried out in the context of video data HAR. In this work, we fill this gap by providing ample experimental results comparing data augmentation and domain adaptation techniques on a cross-viewpoint, human activity recognition task from pose information.

scholarly journals Combining Supervised and Unsupervised Learning Algorithms for Human Activity Recognition

Sensors ◽  
2021 ◽  
Vol 21 (18) ◽  
pp. 6309
Author(s):  
Elena-Alexandra Budisteanu ◽  
Irina Georgiana Mocanu
Keyword(s):  
Unsupervised Learning ◽  
Activity Recognition ◽  
Human Activity ◽  
Data Augmentation ◽  
Learning Algorithms ◽  
Human Activity Recognition ◽  
Convolutional Networks ◽  
Supervised And Unsupervised Learning ◽  
Novel Approach ◽  
Unsupervised Deep Learning

Human activity recognition is an extensively researched topic in the last decade. Recent methods employ supervised and unsupervised deep learning techniques in which spatial and temporal dependency is modeled. This paper proposes a novel approach for human activity recognition using skeleton data. The method combines supervised and unsupervised learning algorithms in order to provide qualitative results and performance in real time. The proposed method involves a two-stage framework: the first stage applies an unsupervised clustering technique to group up activities based on their similarity, while the second stage classifies data assigned to each group using graph convolutional networks. Different clustering techniques and data augmentation strategies are explored for improving the training process. The results were compared against the state of the art methods and the proposed model achieved 90.22% Top-1 accuracy performance for NTU-RGB+D dataset (the performance was increased by approximately 9% compared with the baseline graph convolutional method). Moreover, inference time and total number of parameters stay within the same magnitude order. Extending the initial set of activities with additional classes is fast and robust, since there is no required retraining of the entire architecture but only to retrain the cluster to which the activity is assigned.

scholarly journals IMU-Based Movement Trajectory Heatmaps for Human Activity Recognition

Sensors ◽  
2020 ◽  
Vol 20 (24) ◽  
pp. 7179
Author(s):  
Orhan Konak ◽  
Pit Wegner ◽  
Bert Arnrich
Keyword(s):  
Activity Recognition ◽  
Human Activity ◽  
Data Augmentation ◽  
Short Term Memory ◽  
Inertial Sensor ◽  
Human Activity Recognition ◽  
Training Data ◽  
Sensor Data ◽  
Movement Trajectory ◽  
Movement Trajectories

Recent trends in ubiquitous computing have led to a proliferation of studies that focus on human activity recognition (HAR) utilizing inertial sensor data that consist of acceleration, orientation and angular velocity. However, the performances of such approaches are limited by the amount of annotated training data, especially in fields where annotating data is highly time-consuming and requires specialized professionals, such as in healthcare. In image classification, this limitation has been mitigated by powerful oversampling techniques such as data augmentation. Using this technique, this work evaluates to what extent transforming inertial sensor data into movement trajectories and into 2D heatmap images can be advantageous for HAR when data are scarce. A convolutional long short-term memory (ConvLSTM) network that incorporates spatiotemporal correlations was used to classify the heatmap images. Evaluation was carried out on Deep Inertial Poser (DIP), a known dataset composed of inertial sensor data. The results obtained suggest that for datasets with large numbers of subjects, using state-of-the-art methods remains the best alternative. However, a performance advantage was achieved for small datasets, which is usually the case in healthcare. Moreover, movement trajectories provide a visual representation of human activities, which can help researchers to better interpret and analyze motion patterns.

scholarly journals Data Augmentation and Dense-LSTM for Human Activity Recognition using WiFi Signal

2020 ◽  
pp. 1-1
Author(s):  
Jin Zhang ◽  
Fuxiang Wu ◽  
Bo Wei ◽  
Qieshi Zhang ◽  
Hui Huang ◽  
...  
Keyword(s):  
Activity Recognition ◽  
Human Activity ◽  
Data Augmentation ◽  
Human Activity Recognition ◽  
Wifi Signal
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