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In the process of facial expression recognition, face detection is the prerequisite, image preprocessing is the foundation, facial expression feature extraction is the key, and facial expression classification is the target. Effective feature extraction in this process can improve the accuracy of facial expression classifications. On the other hand, traditional facial expression recognition methods are not only complicated in the feature extraction process, but also unable to obtain more in-depth high-semantic features and deep features from the original image. To solve the above problems, this paper proposes a facial expression recognition method based on multi-channel fusion and lightweight neural network. First, a cascade classifier based on Haar features is used to detect the face region of the facial expression image. Second, the local binary pattern (LBP) is used to extract the local texture features from the face region. Third, face edge features are simultaneously obtained by performing edge detection in the face region based on the Canny edge detection algorithm. Fourth, the obtained face image, LBP texture feature image, and edge detection Canny image are fused, and the fused image is input into the constructed lightweight neural network for training and recognition. Experiments are carried out on the public image databases Facial Expression Recognition 2013 (Fer2013) and extended Cohn–Kanade (CK +) using the hold-out cross-validation method. The experimental results show that the proposed method effectively extracts more complete image features by combining traditional feature extraction algorithms with deep learning feature extraction algorithms, improves the accuracy and robustness of facial expression recognition, and has better recognition rate and generalization ability compared to other mainstream methods. [ABSTRACT FROM AUTHOR]

The autonomous underwater vehicle (AUV) has a problem with feature loss when recognizing small targets underwater. At present, algorithms usually use multi-scale feature extraction to solve the problem, but this method increases the computational effort of the algorithm. In addition, low underwater light and turbid water result in incomplete information on target features. This paper proposes an enhanced dilated convolution framework (EHDC) for underwater blurred target recognition. Firstly, this paper extracts small target features through hybrid dilated convolution networks, increasing the perceptive field of the algorithm without increasing the computational power of the algorithm. Secondly, the proposed algorithm learns spatial semantic features through an adaptive correlation matrix and compensates for the missing features of the target. Finally, this paper fuses spatial semantic features and visual features for the recognition of small underwater blurred targets. Experiments show that the proposed method improves the recognition accuracy by 1.04% compared to existing methods when recognizing small underwater blurred targets. [ABSTRACT FROM AUTHOR]

Facial expression recognition based on residual networks is important for technologies related to space human-robot interaction and collaboration but suffers from low accuracy and slow computation in complex network structures. To solve these problems, this paper proposes a multiscale feature fusion attention lightweight wide residual network. The network first uses an improved random erasing method to preprocess facial expression images, which improves the generalizability of the model. The use of a modified depthwise separable convolution in the feature extraction network reduces the computational effort associated with the network parameters and enhances the characterization of the extracted features through a channel shuffle operation. Then, an improved bottleneck block is used to reduce the dimensionality of the upper layer network feature map to further reduce the number of network parameters while enhancing the network feature extraction capability. Finally, an optimized multiscale feature lightweight attention mechanism module is embedded to further improve the feature extractability of the network for human facial expressions. The experimental results show that the accuracy of the model is 73.21%, 98.72%, and 95.21% on FER2013, CK+ and JAFFE, respectively, with a covariance of 10.14 M. Compared with other networks, the model proposed in this paper has faster computing speed and better accuracy at the same time. [ABSTRACT FROM AUTHOR]

Federated learning is designed to solve the problem of data fragmentation and data isolation based on privacy protection in distributed machine learning. In the federated learning system, participants collaboratively train a model. Each participant uses local data to train the local model, and uploads the trained local model to the server for aggregation. In the real application environment, the data distribution between nodes is often very different, resulting in the accuracy of federated learning model is low. In order to solve the influence of non-independent identically distributed data on the accuracy of the model, this paper proposed a clustering federated learning framework by using the similarity of data distribution between different nodes. Extensive experiments were conducted on Synthetic, CIFAR-10 and FEMNIST standard datasets. Compared with other federated learning methods, clustering federated learning based on data distribution greatly improves the accuracy of the model and requires less computation. [ABSTRACT FROM AUTHOR]

At present, there are some problems in underwater low light image, such as low contrast, blurred details, color distortion. In the process of low illumination image enhancement, there are often problems such as artifacts, loss of edge details and noise amplification in the enhanced image. In this paper, we propose an underwater low-light enhancement algorithm based on U-shaped generative adversarial network, combined with bright channel prior and attention mechanism, to address the problems. For the problems of uneven edges and loss of details that occurred in traditional enhanced images, we propose a two-channel fusion technique for the input channel. Aiming at the problems of brightness, texture and color distortion in enhanced images, we propose a feature extraction technique based on the attention mechanism. For the problems of noise in enhanced output images, we propose a multi-loss function to constrain the network. The method has a wide range of applications in underwater scenes with large depth. This method can be used for target detection or biological species identification in underwater low light environment. Through the enhancement experiment of underwater low light image, the proposed method effectively solves the problems of low contrast, blurred details, color distortion, etc. of underwater low light image. Finally, we performed extensive comparison experiments and completed ablation experiments on the proposed method. The experimental results show that the proposed method is optimal in human visual experience and underwater image quality evaluation index. [ABSTRACT FROM AUTHOR]

In order to categorize feature classes by capturing subtle differences, hyperspectral images (HSIs) have been extensively used due to the rich spectral-spatial information. The 3D convolution-based neural networks (3DCNNs) have been widely used in HSI classification because of their powerful feature extraction capability. However, the 3DCNN-based HSI classification approach could only extract local features, and the feature maps it produces include a lot of spatial information redundancy, which lowers the classification accuracy. To solve the above problems, we proposed a spatial attention network (SATNet) by combining 3D OctConv and ViT. Firstly, 3D OctConv divided the feature maps into high-frequency maps and low-frequency maps to reduce spatial information redundancy. Secondly, the ViT model was used to obtain global features and effectively combine local-global features for classification. To verify the effectiveness of the method in the paper, a comparison with various mainstream methods on three publicly available datasets was performed, and the results showed the superiority of the proposed method in terms of classification evaluation performance. [ABSTRACT FROM AUTHOR]

Multimodal tasks based on attention mechanism and language face numerous problems. Based on multimodal hierarchical attention mechanism and genetic neural network, this paper studies the application of image segmentation algorithm in data completion and 3D scene reconstruction. The algorithm refers to the process of concentrating attention that humans subjectively pay attention to and calculates the difference between each pixel in the genetic neural network test image in the color space and the average value of the target image, which solves the problem of static feature maps and dynamic feature maps of image sequences. In addition, in view of the problem that the number of attention enhancement feature extraction modules is too large and the parameters are too large, the recursive mechanism is used as the feature extraction branch, and new model parameters are not added when the network depth is increased. The simulation results show that the accuracy of the improved image saliency detection algorithm based on the attention mechanism reaches 89.7%, and the difference between the average value of the single-point pixel and the target image is reduced to 0.132, which further promotes the practicability and reliability of the image segmentation model. [ABSTRACT FROM AUTHOR]

Celebrity Profiling is a type of text classification problem which is used for predicting the profiling features like birthyear, gender, fame and occupation of celebrity authors by analysing their writing styles. PAN competition introduced this task in 2019 competition. They provided a corpus for celebrity profiling task and the corpus contains four characteristics like gender, birth-year, fame and occupation of celebrity authors. In order to differentiate the authors writing style the researchers extracted a different types of features such as style based, content based, lexical, character based, syntactic and structural features in the approaches of celebrity profiling. The researchers found that content based features play a crucial role when contrasted with other features in the identification of the author. In this work, the content based features are used in the experiment of celebrity profiling. The frequencies of terms in the total corpus are considered to recognize the important features for the experiment. The most frequent terms are used as features for representing the document vectors. The term value in the vector representation plays a vital role to enhance the performance of celebrity profiling. The Term Weight Measures (TWMs) are used for this purpose to compute the importance of a term in a document. In existing literature, various TWMs are proposed by the researchers in various research domains. In this paper, a term weight measures based approach is proposed for celebrity profiling. In this approach, a new TWM is proposed and compared the performance of proposed term weight measure with existing term weight measures. We observed from the results of celebrity profiling the proposed term weight measure attained best accuracies for profiles prediction than other term weight measures. Three Machine Learning (ML) algorithms such as Naïve Bayes (NB), Support Vector Machine (SVM) and Random Forest (RF) are used for evaluating the performance of proposed approach. The PAN 2019 competition celebrity profiling corpus is used in this work. We considered gender, fame and occupation profiles prediction. [ABSTRACT FROM AUTHOR]

Existing deep learning based single image super-resolution (SISR) models usually improve the fitting ability of the model by increasing the number of network layers, but fail to fully extract and reuse features, leading low quality of reconstructed images. To solve this problem, this paper proposed an image super-resolution model based on feature fusion and attention mechanism. This model used residual in residual (RIR) structure in feature extraction module. The feature extraction module of the network consisted of several residual groups. Each residual group consisted of several residual blocks. This module implemented local feature fusion in each residual group and global feature fusion between each group. In addition, this model introduced coordinate attention module into each residual block and spatial attention module into each residual group. It verifies that the model is able to fully extract features and reuse features. The final experimental results show that the model is superior to the existing models in objective evaluation indexes and subjective visual effect. [ABSTRACT FROM AUTHOR]

Aiming at the problems of difficult feature extraction and low recognition accuracy of coal and gangue, this paper proposes a recognition method based on dielectric and geometric features, which uses variational mode decomposition (VMD) to denoise the response signal to obtain its dielectric features; uses the marked watershed method to segment the image boundary to obtain its geometric features. The dielectric and geometric characteristic parameters of coal and gangue are extracted to construct the classification model of support vector machines (SVM). It takes only 0.001483 s for the secondary SVM classification model to process 60 groups of test samples, and the recognition accuracy is 98.33%, which is superior to the constructed SVM classification model, k-nearest neighbor (KNN) classification model, and back propagation neural network (BP) classification model. This method opens up a new way to solve the problem of coal and gangue identification. [Display omitted] • A recognition model of coal and gangue based on dielectric characteristics and geometric constraints is proposed. • The effective thickness and position of coal and gangue in capacitor should be strictly controlled. • The geometric features of coal and gangue are extracted by industrial camera. • A VMD- Kalman denoising method is proposed. • Quadratic support vector machine algorithm has excellent performance in processing eigenvectors. [ABSTRACT FROM AUTHOR]

Intelligence modeling interpretable for incipient fault diagnosis of batch process represents a serious challenge. For the multivariate, nonlinear, and high-dimensionality characteristics of process data, existing fault diagnosis solutions are easily concealed by noise while neglect the low amplitude and noise interference of the incipient faults. In this paper, an intelligent incipient fault diagnosis model based on deep time series feature extraction network is proposed, which integrates denoising autoencoder (DAE), layer normalization and dropout layer added LSTM (LD-LSTM), and stacked autoencoder (SAE) to obtain the efficient features. DAE is applied to restore the data and eliminate noise interference. LD-LSTM is utilized to extract time series features, in which the layer normalization and the dropout layer are added between the layers of the LSTM to solve the problems of slow model convergence and over-fitting. SAE performs the feature extraction to obtain deep time series features and learns more efficient expressions. The softmax function is applied to achieve the incipient fault diagnosis based on the deep time series features. A case study on a fed-batch penicillin fermentation process suggests that the proposed method can obtain an accuracy rate of 98.97%, which has increased an average of 20% than the traditional shallow machine learning. The accuracy of fault recognition and comparative experiments demonstrate the effectiveness and feasibility of this model, and provide a solution for the application of intelligent fault diagnosis in batch industries. [ABSTRACT FROM AUTHOR]

Recently, deep learning has become a promising technique for constructing gesture recognition classifiers from surface electromyography (sEMG) signals in human–computer interaction. In this paper, we propose a gesture recognition method with sEMG signals based on a deep multi-parallel convolutional neural network (CNN), which solves the problem that traditional machine learning methods may lose too much useful information during feature extraction. CNNs provide an efficient way to constrain the complexity of feedforward neural networks by weight sharing and restriction to local connections. Sophisticated feature extraction is to be avoided and hand gestures are to be classified directly. A multi-parallel and multi-convolution layer convolution structure is proposed to classify hand gestures. Experiment results show that in comparison with five traditional machine learning methods, the proposed method could achieve higher accuracy. [ABSTRACT FROM AUTHOR]

Iris image-based biometric systems are commonly used in applications that demand security, authentication, recognition and faster login access. In solving these real-time problems, the impact of soft computing techniques which employ cognitive skills is very high. Although this system has been commercialized, the scope for improvement is still plenty. This paper introduces the reader to different segments of an iris recognition system and reviews the techniques involved with each segment. It reports on how research articles validate the robustness of an iris-based recognition system. As these systems are fallible, it also shows the vulnerabilities associated with each segment and provides insights to develop much better intelligent and robust techniques which will make the system more accurate. This paper also shows that in spite of versatility of soft computing techniques, it is not fully exploited for iris recognition systems. The present challenges and directions for future research are also discussed. [ABSTRACT FROM AUTHOR]

Author identification always plays an important role in the public security and literary inspection work. Texts feature extraction is cumbersome and not universal. To solve this problem, this paper proposed the CABLSTM Chinese microblog author identification model without expert feature modeling, and tested the accuracy of the model in the open microblog corpus. This model maximized the extraction of short text features, fused the attention mechanism in the CNN and removed the pooling layer, and obtained context-related information through the bidirectional LSTM. The identity recognition result was output through the softmax layer. Experimental results show that the model has a certain improvement in accuracy, recall rate, and F-measure in comparison with traditional machine learning algorithms and TextCNN and LSTM algorithms in the identification task of Chinese microblog authors. [ABSTRACT FROM AUTHOR]

Graph-based semi-supervised dimension reduction can use the inherent graph structure of samples to propagate label information, and has become a hot research field in machine learning. However, most current methods have strict linear constraints and cannot handle data sampled from nonlinear manifolds; and rely on predefined graphs, which cannot capture the local structure information of data and cannot handle complex non-Gaussian data. To address these issues, this paper proposes a new locality-preserved flexible dimension reduction framework, called Semi-supervised Flexible Adaptive Graph Embedding (SFAG), which learns the embedding space that can preserve the local neighborhood structure by constructing a k 1 -nearest neighbor graph over labeled samples. Then, another k 2 -nearest neighbor graph is constructed on all samples to adaptively construct the optimal graph, clustering labeled and unlabeled embedding sample points with neighborhood relations into the same sub-manifold sharing the same label information. Last but not least, the hard linear projection constraint is relaxed by adding residual terms to obtain not only the nonlinear embedding of the training samples, but also the linear projection matrix applied directly to the out-of-sample. In addition, two different semi-supervised dimension reduction methods for adaptive construction of optimal graphs are proposed based on the SFAG framework. Several evaluation experiments validate the effectiveness of our method in exploring manifold structures and classification tasks. • A novel semi-supervised adaptive flexible dimension reduction method is proposed. • The local and global structure of the data is explored by constructing kNN graphs. • The hard linear constraints on the projection are relaxed by adding a residual term. • An algorithm is designed to solve the norm-constrained problem of feature extraction. [ABSTRACT FROM AUTHOR]

A fall is an abnormal activity that occurs rarely; however, missing to identify falls can have serious health and safety implications on an individual. Due to the rarity of occurrence of falls, there may be insufficient or no training data available for them. Therefore, standard supervised machine learning methods may not be directly applied to handle this problem. In this paper, we present a taxonomy for the study of fall detection from the perspective of availability of fall data. The proposed taxonomy is independent of the type of sensors used and specific feature extraction/selection methods. The taxonomy identifies different categories of classification methods for the study of fall detection based on the availability of their data during training the classifiers. Then, we present a comprehensive literature review within those categories and identify the approach of treating a fall as an abnormal activity to be a plausible research direction. We conclude our paper by discussing several open research problems in the field and pointers for future research. [ABSTRACT FROM AUTHOR]

Highlights • Proposed Class Specific Mean Autoencoder for learning class representative features. • Designed an efficient algorithm for adulthood classification based on facial images, relevant for restricted access. • Proposed Multi-Resolution Face Database of more than 4000 images comprising of 317 subjects, both minors and adults. • Experimental evaluation on two large datasets - Multi-Ethnicity and MORPH dataset. • State-of-the-art results after comparison with existing Deep Learning models and commercial system. Abstract Predicting if a person is an adult or a minor has several applications such as inspecting underage driving, preventing purchase of alcohol and tobacco by minors, and granting restricted access. The challenging nature of this problem arises due to the complex and unique physiological changes that are observed with age progression. This paper presents a novel deep learning based formulation, termed as Class Specific Mean Autoencoder, to learn the intra-class similarity and extract class-specific features. We propose that the feature of a particular class if brought similar/closer to the mean feature of that class can help in learning class-specific representations. The proposed formulation is applied for the task of adulthood classification which predicts whether the given face image is of an adult or not. Experiments are performed on two large databases and the results show that the proposed algorithm yields higher classification accuracy compared to existing algorithms and a Commercial-Off-The-Shelf system. [ABSTRACT FROM AUTHOR]

Highlights • A novel zero-shot learning method is developed to rectify the hubness and domain shift problem. • The proposed method exploits the class level visual samples to learn the projection function. • The unseen visual prototypes are modified by the label correlations and their knns. • The proposed method outperforms existing methods on 5 zero-shot learning datasets. Abstract The number of object classes is increasing rapidly leading to the recognition of new classes difficult. Zero-shot learning aims to predict the labels of the new class samples by using the seen class samples and their semantic representations. In this paper, we propose a simple method to learn the unseen visual prototypes (LUVP) by learning the projection function from semantic space to visual feature space to reduce hubness problem. We exploit the class level samples rather than instance level samples, which can alleviate expensive computational costs. Since the disjointness of seen and unseen classes, directly applying the projection function to unseen samples will cause a domain shift problem. Thus, we preserve the unseen label semantic correlations and then adjust the unseen visual prototypes to minimize the domain shift problem. We demonstrate through extensive experiments that the proposed method (1) alleviates the hubness problem, (2) overcomes the domain shift problem, and (3) significantly outperforms existing methods for zero-shot classification on five benchmark datasets. [ABSTRACT FROM AUTHOR]

Multimodal recognition of affective states is a difficult problem, unless the recording conditions are carefully controlled. For recognition “in the wild”, large variances in face pose and illumination, cluttered backgrounds, occlusions, audio and video noise, as well as issues with subtle cues of expression are some of the issues to target. In this paper, we describe a multimodal approach for video-based emotion recognition in the wild. We propose using summarizing functionals of complementary visual descriptors for video modeling. These features include deep convolutional neural network (CNN) based features obtained via transfer learning, for which we illustrate the importance of flexible registration and fine-tuning. Our approach combines audio and visual features with least squares regression based classifiers and weighted score level fusion. We report state-of-the-art results on the EmotiW Challenge for “in the wild” facial expression recognition. Our approach scales to other problems, and ranked top in the ChaLearn-LAP First Impressions Challenge 2016 from video clips collected in the wild. [ABSTRACT FROM AUTHOR]

Recently, learning-based hashing methods which are designed to preserve the semantic information, have shown promising results for approximate nearest neighbor (ANN) search problems. However, most of these methods require a large number of labeled data which are difficult to access in many real applications. With very limited labeled data available, in this paper we propose a semi-supervised hashing method by integrating manifold embedding, feature representation and classifier learning into a joint framework. Specifically, a semi-supervised manifold embedding is explored to simultaneously optimize feature representation and classifier learning to make the learned binary codes optimal for classification. A two-stage hashing strategy is proposed to effectively address the corresponding optimization problem. At the first stage, an iterative algorithm is designed to obtain a relaxed solution. At the second stage, the hashing function is refined by introducing an orthogonal transformation to reduce the quantization error. Extensive experiments on three benchmark databases demonstrate the effectiveness of the proposed method in comparison with several state-of-the-art hashing methods. [ABSTRACT FROM AUTHOR]

Clinical narrative text includes information related to a patient's medical history such as chronological progression of medical problems and clinical treatments. A chronological view of a patient's history makes clinical audits easier and improves quality of care. In this paper, we propose a clinical Problem-Action relation extraction method, based on clinical semantic units and event causality patterns, to present a chronological view of a patient's problem and a doctor's action. Based on our observation that a clinical text describes a patient's medical problems and a doctor's treatments in chronological order, a clinical semantic unit is defined as a problem and/or an action relation. Since a clinical event is a basic unit of the problem and action relation, events are extracted from narrative texts, based on the external knowledge resources context features of the conditional random fields. A clinical semantic unit is extracted from each sentence based on time expressions and context structures of events. Then, a clinical semantic unit is classified into a problem and/or action relation based on the event causality patterns of the support vector machines. Experimental results on Korean discharge summaries show 78.8% performance in the F1-measure. This result shows that the proposed method is effectively classifies clinical Problem-Action relations. [ABSTRACT FROM AUTHOR]

• Extracting weak fault features from complex bearing signals. • Diagnosing the fault of the bearing according to the impulse and periodicity. • Improving the running speed of dictionary learning algorithm. Generally, the transient characteristics of early bearing failure are not obvious. How to extract weak transient features is a big challenge. Dictionary learning has been successfully used to extract bearing fault features. However, the traditional dictionary learning is easy to fall into local optimum and cannot extract fault features from complex signals. And it often consumes huge computational costs. In order to solve the above problems, this paper proposes a fault pulse extraction and feature enhancement method for bearing fault diagnosis. Firstly, the bearing vibration signal is segmented in the time domain. Then this paper proposes a multi-scale alternating direction multiplier method for dictionary learning (MADMMDL) to extract fault impact signal from the segment signal. Finally, frequency spectrum averaging is used to enhance the bearing fault characteristic frequency. Through numerical simulation and rail transit transmission failure simulation experimental analysis, the feasibility of this method in bearing fault diagnosis is verified. [ABSTRACT FROM AUTHOR]

Distant supervision (DS) automatically annotates free text with relation mentions from existing knowledge bases (KBs), providing a way to alleviate the problem of insufficient training data for relation extraction in natural language processing (NLP). However, the heuristic annotation process does not guarantee the correctness of the generated labels, promoting a hot research issue on how to efficiently make use of the noisy training data. In this paper, we model two types of biases to reduce noise: (1) bias-dist to model the relative distance between points (instances) and classes (relation centers); (2) bias-reward to model the possibility of each heuristically generated label being incorrect. Based on the biases, we propose three noise tolerant models: MIML-dist, MIML-dist-classify, and MIML-reward, building on top of a state-of-the-art distantly supervised learning algorithm. Experimental evaluations compared with three landmark methods on the KBP dataset validate the effectiveness of the proposed methods. [ABSTRACT FROM AUTHOR]

In many machine learning algorithms, a major assumption is that the training and the test samples are in the same feature space and have the same distribution. However, for many real applications this assumption does not hold. In this paper, we survey the problem where the training samples and the test samples are from different distributions. This problem can be referred as domain adaptation . The training samples, always with labels, are obtained from what is called source domains, while the test samples, which usually have no labels or only a few labels, are obtained from what is called target domains. The source domains and the target domains are different but related to some extent; the learners can learn some information from the source domains for the learning of the target domains. We focus on the multi-source domain adaptation problem where there is more than one source domain available together with only one target domain. A key issue is how to select good sources and samples for the adaptation. In this survey, we review some theoretical results and well developed algorithms for the multi-source domain adaptation problem. We also discuss some open problems which can be explored in future work. [ABSTRACT FROM AUTHOR]

Despite the benefits of presence, immersive virtual reality is still too limiting and ineffective to be widely adopted in people׳s everyday lives. One important reason for this is its inability to handle highly diverse 3D interaction tasks, such as object manipulation from different scales, perspectives, reference frames, and dimensions. Inspired by preliminary development of an immersive world builder tool, this paper offers an in-depth presentation of our solution to this problem, using a coordinated, tablet- and HMD-based, hybrid virtual environment (HVE) system. Wearing a non-occlusive HMD, the user is able to view and interact with a tablet mounted on the non-dominant forearm, which provides a multi-touch interaction surface, as well as an exocentric God view of the virtual world. To reduce transition gaps across 3D interaction tasks and interfaces, four coordination mechanisms are proposed, two of which were implemented, and one was evaluated in a user study featuring complex level-editing tasks. Based on subjective ratings, task performance, interview feedback, and video analysis, we found that having multiple seamless Interaction Contexts (ICs) with complementary benefits can lead to good performance and user experience, despite the complexity of learning and using the hybrid system. The results also suggest keeping 3DUI tasks synchronized across the ICs, as this can help users understand their relationships, smoothen within- and between-task IC transitions, and inspire more creative use of different interfaces. Finally, based on these findings, a four-step design process is proposed to aid the process of designing and implementing HVE systems, as well as applying them to appropriate task scenarios. [ABSTRACT FROM AUTHOR]

Abstract: This paper investigates feature subset selection for dimensionality reduction in machine learning. We provide a brief overview of the feature subset selection techniques that are commonly used in machine learning. Different metaheuristic strategies are proposed to solve the feature selection problem – GRASP, Tabu Search and Memetic Algorithm. These three strategies are compared with a Genetic Algorithm (which is the metaheuristic strategy most frequently used to solve this problem) and with other typical feature selection methods, such as Sequential Forward Floating Selection (SFFS) and Sequential Backward Floating Selection (SBFS). The results show that, in general, GRASP and Tabu Search obtain significantly better results than the other methods. [Copyright &y& Elsevier]

Fault detection is a fundamental and important research topic in automatic seismic interpretation since the geometry of faults usually reveals the accumulation and migration of geological resource. In the communities of machine learning, many methods convert the fault detection task into a patch-based binary classification problem to solve. Because there are only a few faults in seismic data, the related classification task is obviously imbalanced, i.e., non-fault samples heavily outnumber fault samples. On considering that the existing CNN models just transform the problem into a balanced two-class task via undersampling, in this paper we attempt to construct CNNs directly from the imbalanced patch data with the assistance of transfer learning. In particular, we use focal loss to robustly learn fault feature representations for both fault and non-fault patches. With the aim to make full use of available data, we adopt transfer learning to enhance the recognition ability of relatively complex patches. The experiments conducted with both synthetic and real seismic data (some slices of the Netherland offshore F3 block in the North Sea) show that the novel method performs very well in detecting faults in seismic data. In supplemental material, the features extracted by the CNNs are visualized for both fault and non-fault patches to get some insights for their good performance. • We apply CNN with the focal loss to detect seismic faults with imbalanced patches. • Transfer learning strategy is used to fine-tune the CNN to classify complex patches. • We consider more types of faults in generated data to improve the CNN' robustness. • The CNN' predicted results are post-processed by some methods to extract fault lines. [ABSTRACT FROM AUTHOR]

Due to the actual operation of the wind turbine, the collected fault data sets are limited, and it is difficult to realize fault diagnosis through the correlation between variables. To solve this problem, a fault diagnosis method based on virtual expansion and spherical mapping model is proposed in this paper. Firstly, Hermite interpolation is applied to discrete wind power data samples to obtain an interpolation curve about the characteristics of the sample, and a synchronous sampling method is adopted for the interpolation curve to construct a virtual sample. Then, the features of the virtual sample are mapped to a three-dimensional space. Define the spherical data model and perform spherical fitting in a three-dimensional coordinate system. Finally, feature extraction is performed on the fitted spherical surface for training and testing extreme learning machine (ELM). The distribution law of fault data in the spherical model is summarized. Using the data generated based on the Bootstrap method as a control group, comparative experiments were carried out in back-propagation neural network (BP), Probabilistic Neural Network (PNN), General Regression Neural Network (GRNN), and Support Vector Machine (SVM), which verified the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

Data-driven chatter detection techniques avoid complex physical modeling and provide the basis for industrial applications of cutting process monitoring. Among them, feature extraction is the key step of chatter detection, which can compensate for the accuracy disadvantage of machine learning algorithms to some extent if the extracted features are highly correlated with the milling condition. However, the classification accuracy of the current feature extraction methods is not satisfactory, and a combination of multiple features is required to identify the chatter. This limits the development of unsupervised machine learning algorithms for chattering detection, which further affects the application in practical processing. In this paper, the fractal feature of the signal is extracted by structure function method (SFM) for the first time, which solves the problem that the features are easily affected by process parameters. Milling chatter is identified based on k-means algorithm, which avoids the complex process of training model, and the judgment method of milling chatter is also discussed. The proposed method can achieve 94.4% identification accuracy by using only one single signal feature, which is better than other feature extraction methods, and even better than some supervised machine learning algorithms. Moreover, experiments show that chatter will affect the distribution of cutting bending moment, and it is not reliable to monitor tool wear through the polar plot of the bending moment. This provides a theoretical basis for the application of unsupervised machine learning algorithms in chatter detection. [ABSTRACT FROM AUTHOR]

Most existing object tracking methods have poor adaptability to complex scenes, and cannot achieve a good balance between tracking accuracy and real-time performance. To solve the above problems, this paper proposes a lightweight UAV object real-time tracking algorithm based on strategy gradient and attention. Firstly, a lightweight E-Mobile Net is designed as the backbone network of feature extraction; secondly, a feature enhanced attention assistant module is designed to enhance the adaptability and discrimination ability of the model; with multi-layer feature fusion regional suggestion network, foreground background classification and boundary box regression response map are obtained by cross-correlation, and the tracking results are calculated. The strategy network based on strategy gradient is used to optimize the template update and re detection strategy, which improves the overall tracking accuracy and efficiency of the model. Simulation experiments on an embedded device and multiple standard data sets show that compared with the current mainstream algorithms, the tracking accuracy is significantly improved 20% ∼ 30%, the algorithm robustness also has obvious advantages, and the tracking speed on an embedded device is 56 fps can meet the real-time requirements. [ABSTRACT FROM AUTHOR]

To solve the problems of low accuracy, low real-time performance, poor robustness and others caused by the complex environment, this paper proposes a face mask recognition and standard wear detection algorithm based on the improved YOLO-v4. Firstly, an improved CSPDarkNet53 is introduced into the trunk feature extraction network, which reduces the computing cost of the network and improves the learning ability of the model. Secondly, the adaptive image scaling algorithm can reduce computation and redundancy effectively. Thirdly, the improved PANet structure is introduced so that the network has more semantic information in the feature layer. At last, a face mask detection data set is made according to the standard wearing of masks. Based on the object detection algorithm of deep learning, a variety of evaluation indexes are compared to evaluate the effectiveness of the model. The results of the comparations show that the mAP of face mask recognition can reach 98.3% and the frame rate is high at 54.57 FPS, which are more accurate compared with the exiting algorithm. [ABSTRACT FROM AUTHOR]