Background: convolutional autoencoder (CAE) is an unsupervised feature learning method and shows excellent performance in multivariate fault diagnosis. However, CAE cannot guarantee that the extracted feature is alway...
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Background: convolutional autoencoder (CAE) is an unsupervised feature learning method and shows excellent performance in multivariate fault diagnosis. However, CAE cannot guarantee that the extracted feature is always related to the fault type due to its unsupervised self-reconstruction in the pretraining ***: To solve this problem, a new feature learning method, supervised convolutional autoencoder (SCAE) is proposed to pretrain the network and learn representative feature containing internal spatial information and fault information. In the SCAE, process sample and corresponding label are reconstructed by multilayer encoding-decoding the raw sample. Meanwhile, to prevent label information overfitting the network, a minimum difference transformation function is introduced into the loss ***: The obtained fault-relevant features can be obviously distinguished between different fault types. The trained pretraining network provides more appropriate predefined parameters for fine-tuning to improve the classification performance. The effectiveness of the proposed method is evaluated by the continuous stirred tank reactor (CSTR) process and the Tennessee Eastman (TE) process.(c) 2021 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.
Visual Place Recognition (VPR) is a challenging task in Visual Simultaneous Localization and Mapping (VSLAM), which expects to find out paired images corresponding to the same place in different conditions. Although m...
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ISBN:
(纸本)9783030880071;9783030880064
Visual Place Recognition (VPR) is a challenging task in Visual Simultaneous Localization and Mapping (VSLAM), which expects to find out paired images corresponding to the same place in different conditions. Although most methods based on convolutional Neural Network (CNN) perform well, they require a large number of annotated images for supervised training, which is time and energy consuming. Thus, to train the CNN in an unsupervised way and achieve better performance, we propose a new place recognition method in this paper. We design a VGG16-based convolutional autoencoder (VGG-CAE), which uses the features outputted by VGG16 as the label of images. In this case, VGG-CAE learns the latent representation from the label of images and improves the robustness against appearance and viewpoint variation. When deploying VGG-CAE, features are extracted from query images and reference images with post-processing, the Cosine similarities of features are calculated respectively and a matrix for feature matching is formed accordingly. To verify the performance of our method, we conducted experiments with several public datasets, showing our method achieves competitive results comparing to existing approaches.
The rising availability of hyperspectral data has increased the attention of anomaly detection for various applications. Anomaly detection aims to find a small number of pixels in the hyperspectral data for which the ...
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ISBN:
(数字)9781510645851
ISBN:
(纸本)9781510645851;9781510645844
The rising availability of hyperspectral data has increased the attention of anomaly detection for various applications. Anomaly detection aims to find a small number of pixels in the hyperspectral data for which the spectral signatures differ significantly from the background. However, for anomalies like camouflage objects in a rural area, the spectral signatures distinguish only by small features. For this purpose, we use a 1D-convolutional autoencoder, which extracts the background spectra's most specific features to reconstruct the spectral signature by minimizing the loss function's error. The difference between the original and the reconstructed data can be exploited for anomaly detection. Since the loss function is minimized based on predominant background spectra, areas with anomalies exhibit higher error values. The proposed anomaly detection method's performance is tested on hyperspectral data in the range of 1000 to 2500 nm. The data was recorded with a drone-based Headwall sensor at approximately 80 m over a rural area near Greding, Germany. The anomalies consist mainly of camouflage materials and vehicles. We compare the performance of a 1D-convolutional autoencoder trained on a data set without the target anomalies for different models. This is done to quantify the number of anomalies in the data set before they inhibit the detection process. Additionally, the detection results are compared to the state-of-the-art Reed-Xiaoli anomaly detector. We present the results by counting the correct detections in relation to the false positives with the receiver operating characteristic and discuss more suitable evaluation approaches for small targets. We show that the 1D-CAE outperforms the Reed-Xiaoli anomaly detector for a false alarm rate of 0.1% by reconstructing the background with a low error and the anomalies with a higher error. The 1D-CAE is suitable for camouflage anomaly detection.
Hyperspectral unmixing aims to acquire pure spectra of distinct substances(endmembers)and fractional abundances from highly mixed *** this paper,a deep unmixing network framework is designed to deal with the noise ***...
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Hyperspectral unmixing aims to acquire pure spectra of distinct substances(endmembers)and fractional abundances from highly mixed *** this paper,a deep unmixing network framework is designed to deal with the noise *** contains two parts:a three⁃dimensional convolutional autoencoder(denoising 3D CAE)which recovers data from noised input,and a restrictive non⁃negative sparse autoencoder(NNSAE)which incorporates a hypergraph regularizer as well as a l2,1⁃norm sparsity constraint to improve the unmixing *** deep denoising 3D CAE network was constructed for noisy data retrieval,and had strong capacity of extracting the principle and robust local features in spatial and spectral domains efficiently by training with corrupted ***,a part⁃based nonnegative sparse autoencoder with l2,1⁃norm penalty was concatenated,and a hypergraph regularizer was designed elaborately to represent similarity of neighboring pixels in spatial *** experiments were conducted on synthetic and real⁃world data,which both demonstrate the effectiveness and robustness of the proposed network.
The remaining useful life (RUL) prediction of rolling bearings plays a key role in improving the safety and reliability assessment for rotating machinery. To accurately describe the degradation degree of bearings and ...
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The remaining useful life (RUL) prediction of rolling bearings plays a key role in improving the safety and reliability assessment for rotating machinery. To accurately describe the degradation degree of bearings and perform RUL prediction, an RUL prediction method of rolling bearing combining convolutional autoencoder (CAE) networks and status degradation model is proposed. Firstly, the CAE is used to extract the features from the degraded bearing data;then the status degradation model is built, and the multi-dimensional health status mapping function is used to downscale the extracted features, and the reduced data points are fused with the Euclidean distance to establish the health status index that can characterize the degraded bearing. Finally, the status degradation function in the constructed model and the online update and prediction algorithm are used to adaptively estimate the RUL. The proposed method is validated with PHM datasets for RUL prediction, and its prediction performance is compared with eight prediction methods. The experimental results show that the proposed approach effectively predicts the RUL of rolling bearings and accurately evaluates the degradation degree of the bearing in a future stage.
Increasing advances in sensing technologies and analytics have led to the proliferation of sensors to monitor structural and infrastructural systems. Accurate sensor data can provide information about structural healt...
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Increasing advances in sensing technologies and analytics have led to the proliferation of sensors to monitor structural and infrastructural systems. Accurate sensor data can provide information about structural health, aid in prognosis, and help calculate forces for vibration control. However, sensors are susceptible to faults such as loss of data, random noise, bias, drift, etc., due to the aging of sensors, defects, or environmental factors. Although traditional signal processing techniques can detect and isolate faults and reconstruct corrupt or missing sensor data, they demand significant human intervention. The continuous rise in computational power and demonstrated efficacy in numerous domains motivates the use of deep learning to minimize human-in-the-loop techniques. In this work, we introduce a novel, deep learning framework for linear systems with time-invariant parameters that identifies the presence and type of fault in sensor data, location of the faulty sensor and subsequently reconstructs the correct sensor data for fault detection, fault classification, and reconstruction. In our framework, first, a convolutional Neural Network (CNN) is used to detect the presence of a fault and identify its type. Next, a suite of individually trained convolutional autoencoder (CAE) networks corresponding to each type of fault are employed for reconstruction. We demonstrate the efficacy of our framework to address both single and multiple sensor faults in synthetically generated data of a simple shear-type structure and experimentally measured data from a simplified arch bridge. While the framework is agnostic of fault-type, we demonstrate its use for four types of fault namely, missing, spiky, random, and drift. For both simulated and experimental datasets with a single fault, our models performed well, achieving 100% accuracy in faulty sensor localization, more than 98.7% accuracy in fault type detection, and more than 99% accuracy in reconstruction. Our framework
Depression is a serious and common psychological disorder that requires early diagnosis and treatment. In severe episodes the condition may result in suicidal thoughts. Recently, the need for building an effective aud...
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Depression is a serious and common psychological disorder that requires early diagnosis and treatment. In severe episodes the condition may result in suicidal thoughts. Recently, the need for building an effective audio-based Automatic Depression Detection (ADD) system has sparked the interest of the research community. To date, most of the reported approaches to recognize depression rely on hand-crafted feature extraction for audio data representation. They combine wide variety of audio-related features to improve the classification performance. However, combining many hand-crafted features including relevant and less-relevant can enlarge the feature space which can lead to high-dimensionality issues as not all the features would carry significant information regarding depression. Having high number of features can make the pattern recognition more difficult and increase the risk of overfitting. To overcome these limitations, an audio-based framework of depression detection which includes an adaptation of a deep learning (DL) technique is proposed to automatically extract the highly relevant and compact feature set. This proposed framework uses an end-to-end convolutional Neural Network based autoencoder (CNN AE) technique to learn the highly relevant and discriminative features from raw sequential audio data, and hence to detect depressed people more accurately. In addition, to address the sample imbalance problem we use a cluster-based sampling technique which highly reduces the risk of bias towards the major class (non-depressed). To evaluate the performance and effectiveness of the proposed pipeline, we perform the experiments on Distress Analysis Interview Corpus-Wizard of Oz (DAIC-WOZ) dataset and compare them with the hand-crafted feature extraction methods and other outstanding studies in this domain. The results show that proposed method outperforms other well-known audio-based ADD models with at least 7% improvement in F-measure for classifying depression
Recent advances in deep neural networks have shown that reconstruction -based methods using autoencoders have potential for anomaly detection in visual inspection tasks. However, there are challenges when applying the...
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Recent advances in deep neural networks have shown that reconstruction -based methods using autoencoders have potential for anomaly detection in visual inspection tasks. However, there are challenges when applying these methods to high -resolution images, such as the need for large network training and computation of anomaly scores. autoencoder-based methods detect anomalies by comparing an input image to its reconstruction in pixel space, which can result in poor performance due to imperfect reconstruction. In this paper, we propose a method to address these challenges by using a conditional patch -based convolutional autoencoder and one -class deep feature classification. We train an autoencoder using only normal images and compute anomaly maps as the difference between the input and output of the autoencoder. We then embed these anomaly maps using a pretrained convolutional neural network feature extractor. Using the deep feature embeddings from the anomaly maps of training samples, we train a one -class classifier to compute an anomaly score for an unseen sample. A simple threshold -based criterion is used to determine if the unseen sample is anomalous or not. We compare our proposed algorithm to state-of-the-art methods on multiple challenging datasets, including a dataset of zipper cursors and eight datasets from the MVTec dataset collection. We find that our approach outperforms alternatives in all cases, achieving an average precision score of 94.77% for zipper cursors and 96.51% for MVTec datasets.
In this study, a convolutional autoencoder is constructed to extract and reconstruct the dynamical processes of soliton collisions in optical fibers. The model demonstrates exceptional reconstruction capabilities, acc...
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With the large-scale access of distributed resources to distribution network operation, there are more and more prosumers on the user side. It forms the basis of load prediction and demand-side management to identify ...
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With the large-scale access of distributed resources to distribution network operation, there are more and more prosumers on the user side. It forms the basis of load prediction and demand-side management to identify different power consumption patterns and establish a typical load characteristic database according to the load data of prosumers. Therefore, a method to build a prosumer load characteristic database based on a deep convolutional autoencoder is proposed. First, the autoencoder network was used to extract the features of the load data collected to reduce the data dimension. Then, the density weight canopy algorithm was used to precluster the data after dimensionality reduction to obtain the initial clustering center and the optimal clustering number K value. The pre-clustering results were combined with the k-means algorithm for clustering, and the typical load characteristic database of prosumers was obtained. Finally, the comparison between the clustering index and the traditional k-means clustering algorithm and the improved k-means direct clustering algorithm proves that the method can effectively improve the accuracy of clustering results.
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