Heterogeneous Graph Neural Networks (HGNNs), have demonstrated excellent capabilities in processing heterogeneous information networks. Self-supervised learning on heterogeneous graphs, especially contrastive self-supervised strategy, shows great potential when there are no labels. However, this approach requires the use of carefully designed graph augmentation strategies and the selection of positive and negative samples. Determining the exact level of similarity between sample pairs is non-trivial.To solve this problem, we propose a novel self-supervised Heterogeneous graph neural network with Optimal Transport (HGOT) method which is designed to facilitate self-supervised learning for heterogeneous graphs without graph augmentation strategies. Different from traditional contrastive self-supervised learning, HGOT employs the optimal transport mechanism to relieve the laborious sampling process of positive and negative samples. Specifically, we design an aggregating view (central view) to integrate the semantic information contained in the views represented by different meta-paths (branch views). Then, we introduce an optimal transport plan to identify the transport relationship between the semantics contained in the branch view and the central view. This allows the optimal transport plan between graphs to align with the representations, forcing the encoder to learn node representations that are more similar to the graph space and of higher quality. Extensive experiments on four real-world datasets demonstrate that our proposed HGOT model can achieve state-of-the-art performance on various downstream tasks. In particular, in the node classification task, HGOT achieves an average of more than 6\% improvement in accuracy compared with state-of-the-art methods.

ABSTRACT Facial expression plays a crucial role during interactions with people. Previous studies on facial expression recognition (FER) have mainly focused on adults, while there are few studies on FER for infants. Due to the apparent differences in facial proportions and facial contours between infants and adults, the FER studies for infants could not be conducted on existing expression datasets. In order to study infant facial expressions in‐depth, we create the infant facial expression recognition (IFER) dataset by collecting 10,240 infant images. Since infants' faces have smooth facial lines and weak sharpness, the inter‐class similarity of facial expressions is higher than adults, and the existing networks for facial expression recognition lack attention to inter‐class similarity. To address the above problems, we propose an effective infant facial expression recognition network named EFNet. In the first stage, the convolutional neural network (CNN) branch and the self‐attention branch extract the overall features of infants' faces. In the second stage, we propose the self‐adaptive attentional centre loss (SACL). The SACL uses the extracted feature maps as contexts to estimate the weights by an attention mechanism and then applies the attentional weights to guide the centre loss. Overall, the SACL facilitates inter‐class separateness and intra‐class compressiveness of related information in an embedding space. The state‐of‐the‐art results on the IFER dataset confirm the remarkable effectiveness of the EFNet.

Fundus disease is a complex and universal disease involving a variety of pathologies. Its early diagnosis using fundus images can effectively prevent further diseases and provide targeted treatment plans for patients. Recent deep learning models for classification of this disease are gradually emerging as a critical research field, which is attracting widespread attention. However, in practice, most of the existing methods only focus on local visual cues of a single image, and ignore the underlying explicit interaction similarity between subjects and correlation information among pathologies in fundus diseases. In this paper, we propose a novel label-aware dual graph neural networks for multi-label fundus image classification that consists of population-based graph representation learning and pathology-based graph representation learning modules. Specifically, we first construct a population-based graph by integrating image features and non-image information to learn patient's representations by incorporating associations between subjects. Then, we represent pathologies as a sparse graph where its nodes are associated with pathology-based feature vectors and the edges correspond to probability of the co-occurrence of labels to generate a set of classifier scores by the propagation of multi-layer graph information. Finally, our model can adaptively recalibrate multi-label outputs. Detailed experiments and analysis of our results show the effectiveness of our method compared with state-of-the-art multi-label fundus image classification methods.

Graph neural networks (GNNs) have demonstrated remarkable success for semisupervised node classification. However, these GNNs are still limited to the conventionally semisupervised framework and cannot fully leverage the potential value of large numbers of unlabeled samples. The pseudolabeling method in semisupervised learning (SSL) is widely recognized because it can clearly leverage unlabeled samples. Nevertheless, the existing pseudolabeling methods usually utilize a fixed threshold for all classes and only use a portion of unlabeled samples (ones with high prediction confidence), which leads to class imbalance and low data utilization. To solve these problems, we propose GNNs with adaptive confidence discrimination (ACDGNN) to fully utilize unlabeled samples for facilitating semisupervised node classification. Specifically, an adaptive confidence discrimination module is designed to divide all unlabeled nodes into two subsets by comparing their confidence scores with the adaptive confidence threshold at each training epoch. Then, different constraint strategies for two subset nodes are employed. Unlabeled nodes with high confidence are used to iteratively expand the label set, while ones with low confidence learn discriminative features by applying contrastive learning. Validated by extensive experiments, the proposed ACDGNN delivers significant accuracy gains over the previous SOTAs: an average improvement of 2.0% on all datasets and 5.7% on the Flickr dataset in particular.

Graph contrastive learning (GCL), as a typical self-supervised learning paradigm, has been able to achieve promising performance without labels and gradually attracts much attention. Graph-level method aims to learn representations of each graph by contrasting two augmented graphs. Previous studies usually simply apply contrastive learning to keep the embeddings of augmented views from the same anchor graph (positive pairs) close to each other, as well as separate the embeddings of augmented views from different anchor graphs (negative pairs). However, it is well-known that the structure of graph is always complex and multiscale, which gives rise to a fundamental question: after graph augmentation, will the previous assumption still hold in reality? Through experimental analytics, we find that the semantic information of two augmented graphs from the same anchor graph may be not consistent, and whether two augmented graphs are positive or negative sample pairs is highly correlated with the multiscale structure of the graph. Based on this observation, we then propose a multiscale subgraph contrastive learning method, named MSSGCL, which can characterize the fine-grained semantic information. Specifically, we generate global and local views at different scales based on subgraph sampling and construct multiple contrastive relationships according to their semantic associations to provide richer self-supervised information. Furthermore, to further improve the generalization performance of the model, we propose an extended model called MSSGCL++. It adopts an asymmetric structure to avoid pushing semantically similar negative samples far away. We further introduce adversarial training to perturb the augmented view and thus construct a more difficult self-supervised training task. Finally, a min-max saddle point problem is optimized and the "free" strategy is used to speed up the training process. Extensive experiments and parametric analysis on 16 real-world graph classification datasets confirm the effectiveness of our proposed approach. Compared with state of the art (SOTA) method, our method achieves improvements of 2% and 1.6% in unsupervised and transfer learning settings, respectively.

Pose diversity is an inherent representative characteristic of 2D images. Due to the 3D to 2D projection mechanism, there is evident content discrepancy among distinct pose images. This is the main obstacle bothering pose transformation related researches. To deal with this challenge, we propose a fine-grained incremental evolution centered pose generation framework, rather than traditional direct one-to-one in a rush. Since proposed approach actually bypasses the theoretical difficulty of directly modeling dramatic non-linear variation, the incurred content distortion and blurring could be effectively constrained, at the same time the various individual pose details, especially clothes texture, could be precisely maintained. In order to systematically guide the evolution course, both global and incremental evolution constraints are elaborately designed and merged into the overall framework. And a novel triple-path knowledge fusion structure is worked out to take full advantage of all available valuable knowledge to conduct high-quality pose synthesis. In addition, our framework could generate a series of valuable by-products, namely the various intermediate poses. Extensive experiments have been conducted to verify the effectiveness of the proposed approach. Code is available at https://github.com/Xiaofei-CN/Incremental-Evolution-Pose-Generation.

Most existing biomedical language models are trained on plain text with general learning goals such as random word infilling, failing to capture the knowledge in the biomedical corpus sufficiently. Since biomedical articles usually contain many tables summarising the main entities and their relations, in the paper, we propose a Tabular knowledge enhanced bioMedical pretrained language model, called TabMedBERT. Specifically, we align entities between table cells, and article text spans with pre-defined rules. Then we add two table-related self-supervised tasks to integrate tabular knowledge into the language model: Entity Infilling (EI) and Table Cloze Test (TCT). While EI masks tokens within aligned entities in the article, TCT converts aligned entities in the table layout into a cloze text by erasing one entity and prompts the model to extract the appropriate span to fill in the blank. Experimental results demonstrate that TabMedBERT surpasses all competing language models without adding additional parameters, establishing a new state-of-the-art performance of 85.59% (+1.29%) on the BLURB biomedical NLP benchmark and 7 additional information extraction datasets. Moreover, the model architecture for TCT provides a straightforward solution to revise information extraction with paired entities.

Graph-level contrastive learning, aiming to learn the representations for each graph by contrasting two augmented graphs, has attracted considerable attention. Previous studies usually simply assume that a graph and its augmented graph as a positive pair, otherwise as a negative pair. However, it is well known that graph structure is always complex and multi-scale, which gives rise to a fundamental question: after graph augmentation, will the previous assumption still hold in reality? By an experimental analysis, we discover the semantic information of an augmented graph structure may be not consistent as original graph structure, and whether two augmented graphs are positive or negative pairs is highly related with the multi-scale structures. Based on this finding, we propose a multi-scale subgraph contrastive learning architecture which is able to characterize the fine-grained semantic information. Specifically, we generate global and local views at different scales based on subgraph sampling, and construct multiple contrastive relationships according to their semantic associations to provide richer self-supervised signals. Extensive experiments and parametric analyzes on eight graph classification real-world datasets well demonstrate the effectiveness of the proposed method.

The lack of label data is one of the significant bottlenecks for Chinese Spelling Check. Existing researches use the automatic generation method by exploiting unlabeled data to expand the supervised corpus. However, there is a big gap between the real input scenario and automatically generated corpus. Thus, we develop a competitive general speller ECSpell, which adopts the Error-consistent masking strategy to create data for pretraining. This error-consistency masking strategy is used to specify the error types of automatically generated sentences consistent with the real scene. The experimental result indicates that our model outperforms previous state-of-the-art models on the general benchmark. Moreover, spellers often work within a particular domain in real life. Due to many uncommon domain terms, experiments on our built domain-specific datasets show that general models perform terribly. Inspired by the common practice of input methods, we propose to add an alterable user dictionary to handle the zero-shot domain-adaption problem. Specifically, we attach a User Dictionary guided inference module (UD) to a general token classification-based speller. Our experiments demonstrate that ECSpell UD , namely, ECSpell combined with UD, surpasses all the other baselines broadly, even approaching the performance on the general benchmark. 1

Graph Neural Networks (GNNs), the powerful graph representation technique based on deep learning, have attracted great research interest in recent years. Although many GNNs have achieved the state-of-the-art accuracy on a set of standard benchmark datasets, they are still limited to traditional semi-supervised framework and lack of sufficient supervision information, especially for the large amount of unlabeled data. To overcome this issue, we propose a novel self-consistent graph neural networks (SCGNN) framework to enrich the supervision information from two aspects: the self-consistency of unlabeled data and the label information of labeled data. First, in order to extract the self-supervision information from the numerous unlabeled nodes, we perform graph data augmentation and leverage a self-consistent constraint to maximize the mutual information of the unlabeled nodes across different augmented graph views. The self-consistency can sufficiently utilize the intrinsic structural attributes of the graph to extract the self-supervision information from unlabeled data and improve the subsequent classification result. Second, to further extract supervision information from scarce labeled nodes, we introduce a fusion mechanism to obtain comprehensive node embeddings by fusing node representations of two positive graph views, and optimize the classification loss over labeled nodes to maximize the utilization of label information. We conduct comprehensive empirical studies on six public benchmark datasets in node classification task. In terms of accuracy, SCGNN improves by an average of 2.08% over the best baseline, and specifically by 5.8% on the Disease dataset.

Measuring the intrinsic deformability of arbitrary small‐scale subdivision of a shape is an interesting meanwhile valuable research topic. Such measurement can be directly utilised as a reliable criteria to partition shape into small components and then assist in shape modelling and description. Compared to global modelling, through constructing subdivision‐based complex shape description, the accuracy and flexibility of shape representation can be significantly improved. In this study, the authors propose a line segment advection (LSA)‐based vertex‐level three‐dimensional shape deformability measuring method. It can highlight the deformability characteristics of each shape part in any scale and size. The measurement is realised mainly based on the advection of line segments connecting neighbouring shape mesh vertices. For 3D shapes, since the line segment of triangular mesh facet directly reflects the minimal neighbourhood relationships and mesh microstructure, its advection can capture the finest details of shape deformability. Then, after transferring that information into neighbouring vertices, a vertex‐level shape deformability measurement can be acquired. Besides, to demonstrate the value of the proposed measuring method to shape partitioning and piecewise shape modelling, a straightforward shape partitioning method is introduced as well. Extensive experiments on three publicly available databases are conducted to verify the effectiveness of proposed methods.

Interesting target detection algorithm in complex natural backgrounds images is studied in this paper. Firstly, logGabor filter bank is analyzed, which is consistent with human visual system characteristics. Several kinds of local features from the filter bank can form the integrated feature. Integrated feature congruency (IFC) model is established. And upon compensating noise for IFC, an improved integrated feature congruency (IIFC) model is obtained, in which, target detecting is translated to find the interest points that are significant across scales and orientations. This model is applied to complex natural backgrounds images for target detection. Experimental results show that this method can detect interesting targets effectively from complex natural backgrounds scenes.