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Video-based facial expression recognition is a potential alternative for detecting the transitional processes of human emotion. In this paper, we present the landmark triangulation-induced altitude signatures to depict gradual changes in human emotion from face video frames. In our proposed approach, we consider the geometry-based triangulation technique which results from the triangles formed by important landmark points on face images. In this work, we measure three altitudes from all triangles and generate three different variations of altitude signature viz. AS1, AS2 and AS3 for the classification of six basic emotions viz. anger (AN), disgust (DI), fear (FE), happiness (HA), sadness (SA) and surprise (SU) in several ways. The performance capability of our proposed recognition system is tested on three benchmark face video datasets: Extended Cohn–Kanade (CK+), M&M Initiative (MMI), and Multimedia Understanding Group (MUG) through the application of Multilayer Perceptron (MLP) classifier and also validated by tenfold cross-validation method. Experimental results, 98.77%, 93.06%, and 98.75% on CK+, MMI, and MUG, respectively, are found very impressive. System efficacy is vindicated by showing the superiority of the proposed technique over the other existing techniques. [ABSTRACT FROM AUTHOR]

The traditional convolutional neural network (CNN)-based methods usually use the spatial information in the amplitude of complex synthetic aperture radar (SAR) images. Several studies have started to concentrate on merging the unique physical properties of SAR images, such as DSN-v1, extracting the backscattering characteristic from the frequency domain. Although DSN-v1 has obtained impressive classification ability, there is some room for improvement. In this letter, DSN-v2 is proposed to boost the classification ability of man-made and natural objects in SAR images. The improvement is reflected in two aspects. First, a multiscale subband feature extraction (MSFE) component is designed for natural objects. Since we observe their multiscale subband spectrum is significantly different, multiple encoders are used to extract effective features. Second, the additive angular margin (AAM) loss is introduced to distinguish man-made objects more clearly by manually adding a margin to the decision boundary. The experimental results on the Sentinel-1 (S1) dataset show that DSN-v2 achieves superior classification performance and model training speed compared with DSN-v1. [ABSTRACT FROM AUTHOR]

Advanced air mobility (AAM) is an emerging industry focus as well as a research and development discipline. Innovations and technologies resulting from AAM will change the way that we move cargo and people in and around cities. Industry is moving fast with excitement to deploy AAM solutions. However, there are multiple technical challenges that need to be overcome before AAM becomes a reality. This article takes a closer look at the technology readiness level of AAM solutions in the area of communications, navigation, and surveillance (CNS) and identifies open research problems as well as directions to address them. In particular, we discuss current approaches and future research challenges in air corridor design, air-to-air (AA) communications, 3rd Generation Partnership Project (3GPP) support for navigation, and detect and avoid (DAA)/collision avoidance, among other areas, for supporting future AAM operations. [ABSTRACT FROM AUTHOR]

In recent years, the recommender system has been widely used in online platforms, which can extract useful information from giant volumes of data and recommend suitable items to the user according to user preferences. However, the recommender system usually suffers from sparsity and cold-start problems. Cross-domain recommendation, as a particular example of transfer learning, has been used to solve the aforementioned problems. However, many existing cross-domain recommendation approaches are based on matrix factorization, which can only learn the shallow and linear characteristics of users and items. Therefore, in this article, we propose a novel autoencoder framework with an attention mechanism (AAM) for cross-domain recommendation, which can transfer and fuse information between different domains and make a more accurate rating prediction. The main idea of the proposed framework lies in utilizing autoencoder, multilayer perceptron, and self-attention to extract user and item features, learn the user and item-latent factors, and fuse the user-latent factors from different domains, respectively. In addition, to learn the affinity of the user-latent factors between different domains in a multiaspect level, we also strengthen the self-attention mechanism by using multihead self-attention and propose AAM++. Experiments conducted on two real-world datasets empirically demonstrate that our proposed methods outperform the state-of-the-art methods in cross-domain recommendation and AAM++ performs better than AAM on sparse and large-scale datasets. [ABSTRACT FROM AUTHOR]

One of the biggest outlooks of face recognition is to create a useful application for human identification at immigration offices for security purposes. The human face is a complex visual pattern that consists of general categorical information, identity specification, primary information, and eccentricity. In this domain, the ethnic identification of humans finds its uses in various real-time applications. Yet, automatic identification does not produce prompt results due to complex characteristics and computational complexity. This paper intends to propose automated human ethnicity identification using facial features, comprising three major processes: pre-processing, feature extraction, and classification. At first, the input image is subjected to a pre-processing method, in which the face detection is carried out using the Viola-Jones face detection algorithm. Then, the pre-processed image is subjected to the feature extraction process, where the color feature, texture feature, forehead area extraction, and the improved active appearance model (AAM) based on unique features are extracted. These extracted features are then subjected to the optimized convolutional neural network (CNN) for ethnicity classification. As the major contribution, training of CNN is carried out by the proposed Moth Spiral adopted Grey Wolf Algorithm (MSGWA) model via tuning the optimal weights. Finally, the performance of the proposed work is compared against the adopted and existing approaches on the basis of certain metrics such as NPV, sensitivity, FDR, accuracy, specificity, FPR, precision, MCC, FNR, and F1-score, respectively. [ABSTRACT FROM AUTHOR]

Non-orthogonal multiple access (NOMA) as a promising technology, can achieve enhanced connectivity and spectral efficiency. However, the asymmetric channels in uplink NOMA systems can bring distinct uncertainty of the bit error rate (BER) and throughput performances to the users. To address this problem, an asymmetric adaptive modulation (AAM) framework for uplink NOMA systems is introduced in this paper. We first derive the closed-form BER expressions for uplink NOMA systems, then we propose a principle for reducing the performance uncertainty. Finally, we develop an AAM algorithm for uplink NOMA systems by studying the closed-form BER expressions. Numerical results demonstrate the correctness of the BER expressions we derived, and show that our AAM algorithm outperforms the benchmark in terms of the system sum throughput. [ABSTRACT FROM AUTHOR]

Text detection in complex scene images is a challenging task for intelligent transportation. Recently, anchor mechanisms are widely utilized in scene text detection tasks. However, in existing methods, anchors are generally predefined empirically, degrading robustness to complex scenarios with various sizes and orientation variations. In this paper, we propose a novel Attention Anchor Mechanism (AAM), especially targeting at predicting appropriate anchors for each pixel. To be concrete, we regard a series of predefined anchors as basic anchors and utilize an attention model to predict weights corresponding to basic anchors. Consequently, the weighted sum of basic anchors in each pixel can obtain a predicted anchor. In this way, the gap between the predicted anchors and the corresponding ground truth boxes could be narrowed, making the network easier to regress. For facilitating the design of basic anchors, we adopt a dimension-decomposition mechanism to predict width, height, and angle of anchors, respectively. Extensive experiments on several public datasets demonstrate that our method achieves state-of-the-art performance. [ABSTRACT FROM AUTHOR]

Data annotation is a fundamental precursor for establishing large training sets to effectively apply deep learning methods to medical image analysis. For cell segmentation, obtaining high quality annotations is an expensive process that usually requires manual grading by experts. This work introduces an approach to efficiently generate annotated images, called “A-GANs”, created by combining an active cell appearance model (ACAM) with conditional generative adversarial networks (C-GANs). ACAM is a statistical model that captures a realistic range of cell characteristics and is used to ensure that the image statistics of generated cells are guided by real data. C-GANs utilize cell contours generated by ACAM to produce cells that match input contours. By pairing ACAM-generated contours with A-GANs-based generated images, high quality annotated images can be efficiently generated. Experimental results on adaptive optics (AO) retinal images showed that A-GANs robustly synthesize realistic, artificial images whose cell distributions are exquisitely specified by ACAM. The cell segmentation performance using as few as 64 manually-annotated real AO images combined with 248 artificially-generated images from A-GANs was similar to the case of using 248 manually-annotated real images alone (Dice coefficients of 88% for both). Finally, application to rare diseases in which images exhibit never-seen characteristics demonstrated improvements in cell segmentation without the need for incorporating manual annotations from these new retinal images. Overall, A-GANs introduce a methodology for generating high quality annotated data that statistically captures the characteristics of any desired dataset and can be used to more efficiently train deep-learning-based medical image analysis applications. [ABSTRACT FROM AUTHOR]

Chloride-induced corrosion of reinforced concrete costs the global economy billions of dollars every year. Despite concerted research effort, the non-invasive, continuous monitoring of sodium chloride in concrete structures is still an unsolved problem. Here, we outline a first-time demonstration of a sodium chloride sensor based on alkali-activated cements: a class of cementitious, electrolytically conductive materials which are typically used for concrete construction and repair. In this work, internal sodium chloride concentrations ranging from 0–22 wt% were measured independently of moisture contents via shifts in electrical impedance. The typical sodium chloride measurement precision was 0.85 wt%. Non-linearity of the sensor response due to signal saturation began at sodium chloride concentrations >5 wt%. We use experimental measures of ion dynamics to link this saturation to the deleterious effect of high concentrations on ion mobility. This study demonstrates sensor feasibility, and provides new experimental evidence to further our understanding of ionic conductivity mechanisms in these materials. The work will allow for the development of self-sensing repair and construction materials for locating and quantifying sodium chloride levels within concrete structures — a valuable technology for supporting concrete health monitoring and maintenance. [ABSTRACT FROM AUTHOR]

Aspect-level sentiment classification determines the sentiment polarity of a targeted aspect. To solve this task, attention-based neural networks are typically adopted to explore the interaction between the aspect and its context in a single sentence. However, such approaches ignore the rich semantic information that can be obtained from other sentences. This article shows that the contexts of aspects with similar meanings should be considered global semantic information that can be incorporated as domain knowledge. Then, a novel global semantic memory network (GSMNet) is proposed to share the global semantic information of various aspects and generate a domain-specific representation. With the help of domain knowledge, crucial words can be focused on more precisely. Moreover, instead of employing the concatenating operation for vectors before classification, GSMNet adopts a fine-grained information fusion layer to capture the importance of representations for efficiently extracting the valid parts of each dimension. The experimental results demonstrate the effectiveness of our model. [ABSTRACT FROM AUTHOR]

Advanced air mobility (AAM) aims at shifting a major part of today's ground-based urban transportation of people and goods into the third (vertical) dimension. Aerial transport routes lead to shorter transport times and relieve ground traffic. Opening up the third dimension for transport in densely populated urban areas requires reliable and alwaysavailable communication to coordinate the multitude of unmanned aerial vehicles (UAVs) to optimize flight trajectories and avoid collisions. As the industry is enthusiastically making progress toward unmanned air transportation, further research and development are needed in this domain. [ABSTRACT FROM AUTHOR]

Currently, attention mechanism receives enormous interest and has been extensively employed in the fields of Person Re-Identification (RE-ID), as it gains superior performance in learning discriminative feature representations. However, most off-the-shelf attention methods are still vulnerable to cross-view inconsistency problem. Besides, they merely exploit imprecise channel attention information and coarse-grained spatial attention of homogeneous scales, being insufficient to capture subtle differences among highly-similar individuals. To this end, we propose a novel Attention-Aligned Network (AANet) to address the aforementioned problems, in which a novel Omnibearing Foreground-aware Attention (OFA) module, Attention Alignment Mechanism (AAM) and an improved triplet loss with hard mining are proposed to learn foreground attentive features for RE-ID. Specifically, AANet firstly leverages OFA module to exploit heterogeneous-scale spatial attention and foreground-aware channel attention information. Then AANet further reduces the impact of background clutter and learns camera-invariant and background-invariant representations by virtue of AAM. Last but not least, an improved triplet loss with hard mining is also introduced to enhance the feature learning capability, which can jointly minimize the intra-class distance and maximize the inter-class distance in each triplet unit. Extensive experiments are carried out to demonstrate that the proposed method outperforms most current methods on three main RE-ID benchmarks. [ABSTRACT FROM AUTHOR]

Pain is an alert state of the human body that can be conveyed to the external world through different modalities. A possible communication channel for human pain is represented by facial expressions, whose role in social interactions has been well established. In this work, the link between pain and transfer entropy (TE), passing through facial expressions, is investigated. A new approach to the vision-based measurement (VBM) of pain is presented, which is based on TE among the time-series of facial landmarks positions. The system is composed of three main blocks: A VBM block for the automatic landmarking and the generation of the time-series from the video-sequences; a second block for the evaluation of TE; and finally a classification model based on machine learning algorithms for pain assessment. A public database of video sequences of patients experiencing pain in a controlled scenario was used for the characterization of the system in terms of accuracy and precision. Different uncertainty contributions related to realistic signals interruptions and fluctuations were modeled and propagated to provide a comprehensive evaluation of the proposed measurement system. The obtained results indicate that TE-based approaches can provide great benefits in automatic pain assessment, opening new perspectives for remote management of patients. [ABSTRACT FROM AUTHOR]

Background: Recently, the field of face and facial features has been progressively studied. The features of facial expression have gained increasing attention for related applications. The wrinkle is the most representative feature, and its research and applications have been topics of high interest. Wrinkles play an important role in face feature analysis. They have been widely used in applications, such as age estimation, skin texture classification, expression recognition, and simulation. Purpose: Existing approaches to the image‐based analysis of wrinkles as texture not as curvilinear discontinuity and wrinkle detection mainly have focused on detecting wrinkles on forehead position, which is usually horizontal linear shapes, while the detection of the nasolabial wrinkle is not well understood due to their variety of shapes and complexity. Method: In this paper, we present a nasolabial wrinkle line detecting effective algorithm based on the Active appearance model and Hessian filter to improve localization results by creating unique initial shapes of the wrinkle lines for each input face image. Results: Experimental results show that the proposed method is capable of tracking curve wrinkle lines, thus allowing to detect complexly structured wrinkle lines. This work demonstrates results illustrated the competitiveness of the proposed method in detecting nasolabial wrinkle lines. Conclusion: In our study, this was introduced the effectiveness of changing the structure of AAM and successfully applied in wrinkle line localizing, although competitive results are achieved by the proposed wrinkle detection method. [ABSTRACT FROM AUTHOR]

To address the problem of weakly supervised instance segmentation for electrical equipment using only a red, green, and blue (RGB) camera, an automatic annotation of masks of samples (AAMS) method based on thermal image guidance is proposed in this article. With only image-level label supervision, we exploit foreground segmentation results of thermal images to guide the instance mask extraction of electrical equipment in RGB images through the heterogeneous pixel registration algorithm between RGB-thermal (RGB-T) image pairs. It is realized to automatically annotate instance masks, which greatly improves efficiency and decreases costs. In addition, we further propose a progressively optimized model (POM) for instance segmentation, which first utilizes the fully connected conditional random field (CRF) and the constrain-to-boundary loss to specify fine-detailed boundaries of each object and to solve the difficulty of segmenting electrical equipment with complicated structures. This model also explores the self-paced learning technology to solve the issue of resolution differences between RGB-T image pairs for improving the generalization ability. By comparison to the other state-of-the-arts, experimental results show that our method can obtain by far the better performance on the electrical equipment data set. [ABSTRACT FROM AUTHOR]

We propose a system architecture that facilitates dynamic assurance of autonomous systems embedding machine learning-based components. We also introduce dynamic assurance cases as a generic framework to provide justified confidence in their capabilities. [ABSTRACT FROM AUTHOR]

The evaluation of temporomandibular joint (TMJ) dysfunction using finite element models is a time consuming process that requires extensive technical knowledge. We combined a statistical active appearance model with automated modelling algorithms to biomechanically study the relationship between TMJ malformations and dysfunction in radiographs from 20 paediatric patients with unilateral crossbite. A fitting algorithm (fitting error < 4%) recognised the TMJ shape and adjusted the dimensions of each patient-specific 2D FE model, which was then used to compute 2 different joint movements. Significant functional differences were observed between the crossbite and non-cross bite sides, and the shape-function relation was verified. [ABSTRACT FROM AUTHOR]

Object recognition and localization is still a very challenging problem, despite recent advances in deep learning (DL) approaches, especially for objects with varying shapes and appearances. Statistical models, such as an Active Shape Model (ASM), rely on a parametric model of the object, allowing an easy incorporation of prior knowledge about shape and appearance in a principled way. To take advantage of these benefits, this paper proposes a new ASM framework that addresses two tasks: $(i)$ comparing the performance of several image features used to extract observations from an input image; and $(ii)$ improving the performance of the model fitting by relying on a probabilistic framework that allows the use of multiple observations and is robust to the presence of outliers. The goal in $(i)$ is to maximize the quality of the observations by exploring a wide set of handcrafted features (HOG, SIFT, and texture templates) and more recent DL-based features. Regarding $(ii)$ , we use the Generalized Expectation-Maximization algorithm to deal with outliers and to extend the fitting process to multiple observations. The proposed framework is evaluated in the context of facial landmark fitting and the segmentation of the endocardium of the left ventricle in cardiac magnetic resonance volumes. We experimentally observe that the proposed approach is robust not only to outliers, but also to adverse initialization conditions and to large search regions (from where the observations are extracted from the image). Furthermore, the results of the proposed combination of the ASM with DL-based features are competitive with more recent DL approaches (e.g. FCN , U-Net and CNN Cascade), showing that it is possible to combine the benefits of statistical models and DL into a new deep ASM probabilistic framework. [ABSTRACT FROM AUTHOR]

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Purpose: An automated, objective, fast and simple classification system for the grading of facial palsy (FP) is lacking. Methods: An observational single center study was performed. 4572 photographs of 233 patients with unilateral peripheral FP were subjectively rated and automatically analyzed applying a machine learning approach including Supervised Descent Method. This allowed an automated grading of all photographs according to House-Brackmann grading scale (HB), Sunnybrook grading system (SB), and Stennert index (SI). Results: Median time to first assessment was 6 days after onset. At first examination, the median objective HB, total SB, and total SI were grade 3, 45, and 5, respectively. The best correlation between subjective and objective grading was seen for SB and SI movement score (r = 0.746; r = 0.732, respectively). No agreement was found between subjective and objective HB grading [Test for symmetry 80.61, df = 15, p < 0.001, weighted kappa = − 0.0105; 95% confidence interval (CI) = − 0.0542 to 0.0331; p = 0.6541]. Also no agreement was found between subjective and objective total SI (test for symmetry 166.37, df = 55, p < 0.001) although there was a nonzero weighted kappa = 0.2670; CI 0.2154–0.3186; p < 0.0001). Based on a multinomial logistic regression the probability for higher scores was higher for subjective compared to objective SI (OR 1.608; CI 1.202–2.150; p = 0.0014). The best agreement was seen between subjective and objective SB (ICC = 0.34645). Conclusions: Automated Sunnybrook grading delivered with fair agreement fast and objective global and regional data on facial motor function for use in clinical routine and clinical trials. [ABSTRACT FROM AUTHOR]

Prostate cancer is the second largest cause of mortality among men. Prostate segmentation, i.e. the precise determination of the prostate region in magnetic resonance imaging (MRI), is generally used for prostate volume measurement, which can be used as a potential prostate cancer indicator. This paper presents a new fully automatic statistical model called the multiobjective active appearance model (MOAAM) for prostate segmentation in MR images. First, in the training stage, the appearance model, including the shape and texture model, is developed by applying principal component analysis to the training images, already outlined by a physician. Then noise and roughness are properly removed in the preprocessing step by Sticks filter and nonlinear filtering. This helps us provide the proper conditions for the prostate region detection. Finally, in order to detect the prostate region, a new multiobjective function is optimized using a suitable search algorithm. The proposed method has been applied to prostate images for segmenting the prostate boundaries. The evaluation results indicate that the presented method can yield a DSC value of 87.4 ± 5.00%, is less sensitive to the edge information and initialization, and has a stronger capture range in comparison with existing methods. [ABSTRACT FROM AUTHOR]