Abstract:Traditional fault diagnosis methods using Convolutional Neural Networks (CNNs) face limitations in capturing temporal features (i.e., the variation of vibration signals over time). To address this issue, this paper introduces a novel model, the Time Series Vision Transformer (TSViT), specifically designed for fault diagnosis. On one hand, TSViT model integrates a convolutional layer to segment vibration signals and capture local features. On the other hand, it employs a transformer encoder to learn long-term temporal information. The experimental results with other methods on two distinct datasets validate the effectiveness and generalizability of TSViT with a comparative analysis of its hyperparameters' impact on model performance, computational complexity, and overall parameter quantity. TSViT reaches average accuracies of 100% and 99.99% on two test sets, correspondingly.
Abstract:Early recognition of abnormal rhythm in ECG signals is crucial for monitoring or diagnosing patients' cardiac conditions and increasing the success rate of the treatment. Classifying abnormal rhythms into fine-grained categories is very challenging due to the the broad taxonomy of rhythms, noises and lack of real-world data and annotations from large number of patients. This paper presents a new ECG classification method based on Deep Convolutional Neural Networks (DCNN) and online decision fusion. Different from previous methods which utilize hand-crafted features or learn features from the original signal domain, the proposed DCNN based method learns features and classifiers from the time-frequency domain in an end-to-end manner. First, the ECG wave signal is transformed to time-frequency domain by using Short-Time Fourier Transform. Next, specific DCNN models are trained on ECG samples of specific length. Finally, an online decision fusion method is proposed to fuse past and current decisions from different models into a more accurate one. Experimental results on both synthetic and real-world ECG datasets convince the effectiveness and efficiency of the proposed method.
Abstract:Modeling statistical regularity plays an essential role in ill-posed image processing problems. Recently, deep learning based methods have been presented to implicitly learn statistical representation of pixel distributions in natural images and leverage it as a constraint to facilitate subsequent tasks, such as color constancy and image dehazing. However, the existing CNN architecture is prone to variability and diversity of pixel intensity within and between local regions, which may result in inaccurate statistical representation. To address this problem, this paper presents a novel fully point-wise CNN architecture for modeling statistical regularities in natural images. Specifically, we propose to randomly shuffle the pixels in the origin images and leverage the shuffled image as input to make CNN more concerned with the statistical properties. Moreover, since the pixels in the shuffled image are independent identically distributed, we can replace all the large convolution kernels in CNN with point-wise ($1*1$) convolution kernels while maintaining the representation ability. Experimental results on two applications: color constancy and image dehazing, demonstrate the superiority of our proposed network over the existing architectures, i.e., using 1/10$\sim$1/100 network parameters and computational cost while achieving comparable performance.