The recent developments in technologies bring not only increasing amount of information but also multiple information sources for Graph Representation Learning. With the success of Graph Neural Networks (GNN), there have been increasing attempts to learn representation of multi-source information leveraging its graph structures. However, existing graph methods basically combine multi-source information with different contribution scores and over-simplify the graph structures based on prior knowledge, which fail to unify complex and conflicting multi-source information. Multisensory Processing theory in cognitive neuroscience reveals human mechanism of learning multi-source information by identifying the redundancy and complementarity. Inspired by that, we propose Graph Redundancy Network (GRN) that: 1). learns a suitable representation space that maximizes multi-source interactions; 2). encodes the redundant and complementary information according to Graph Intersection and Difference of their graph structures; 3). further reinforces and explores the redundant and complementary information through low-pass and high-pass graph filters. The empirical study shows that GRN outperforms existing methods on various tasks.

Graph Convolutional Networks (GCNs) have made outstanding achievements in many tasks on graphs in recent years, but their success relies on sufficient training data. In practice, sparsely labeled graphs widely exist in the real world so self-training methods have become popular approaches by adding pseudo labeled nodes to enhance the performance of GCNs. However, we observe that most selected high-confidence pseudo labeled nodes by the existing methods would surround the true labeled nodes. It is what we called pseudo label over-dependence, which could lead to the non-uniform pseudo label distribution. Furthermore, a thorough experiment shows that the classification accuracy changes significantly under different label densities and the label-sparse regions show great potential improvement in the model performance. Based on the above findings, we theoretically analyze the constraint factors in the label-sparse regions and further propose reducing the feature distribution difference between the label-dense regions and label-sparse regions can effectively decrease the classification error. Thus, in this paper, we propose a novel Graph Label Information Migration framework (GLIM) to liberate pseudo labels from over-dependence. Specifically, we first propose a training dynamics module (TDM) that uses abundant training process information to find more reliable node labels and improve the model robustness against label noise. Then we propose a label migration module (LMM) that migrates label information from label-dense regions to label-sparse regions by a spectral based graph matching algorithm. These migrated labels are like the glimmers in the darkness, providing the supervision signals for the unlabeled nodes in label-sparse regions. Finally, we conduct extensive experiments to demonstrate the effectiveness of the proposed GLIM.

Graph Neural Networks (GNNs) have achieved great success in recent years for their remarkable ability to extract effective representations from both node features and graph structures. Most of GNNs only focus on graphs with homogeneous features that correspond to one single feature field. For tabular features that are heterogeneous with multiple feature fields, GNNs often perform less favorably compared to machine learning methods such as boosted trees. In this work, we propose a new perspective to uncover the problem of GNNs on graphs with tabular features through both empirical study and theoretical analysis. The assumption of GNNs that connected nodes exhibit similar patterns can barely hold true for tabular features since multiple feature fields already exhibit different patterns. And propagation on such mismatched graph causes propagated features overcorrelated on graphs, which leads to the reduction of feature diversity and the increase of information redundancy. Therefore, we propose Field-aware Decorrelation Neural Network for graphs with tabular features (GraphFADE), a novel framework that directly optimizes the overcorrelation problem for graphs with tabular features. We first hierarchically partition the dataset into subsets with minimal correlation and then according to the decorrelation clustering results assemble the optimal matched graphs for each feature dimension to propagate on. The empirical study shows that our method achieves superior performance on multiple graphs with tabular features, demonstrating the effectiveness of our model.

Lightweight video compression has effectively alleviated the tension between growing transmission demands and expensive integration upgrades. Effective rate control algorithms are believed to be the crucial bottleneck for quality improvement during those ultra-high throughput coding processes. This paper proposes a novel rate control (RC) scheme that constructs a contextual adaptive bit estimation model through clustering historical compression information into block-gradient complexity categories. A buffer-aware tuning method and a flexible quantization parameter (QP) mapping algorithm are designed to determine the Luma/Chroma QP distribution where a simplified Lagrangian multiplier is further defined to preserve the stability of the overall compression process. As a result, the constant-bitrate compression towards low-latency interoperable ASICs is implemented with a promising RC performance.

This paper proposes a pixel-wise quantization (PWQ) method, which allows to reduce the quantization parameters (QPs) of simple pixels adaptively for the purpose of enhancing the subjective quality, since the distortions on simple pixels are more noticeable than those on complex pixels. For the pixel-wise prediction in Fig. 1, the pixel-wise reconstruction is implemented and the transformation is disabled, where the symbol “=” (or $^{\prime \prime}\vee^{\prime \prime}/^{\prime \prime}\gt^{\prime \prime}$) means the current prediction is the average value of the left and right reconstructions (or the upper/left reconstruction). And the PWQ method is applied in the same prediction direction and reconstruction order, with adjusting the current pixel QP $(Q_{pixel})$ adaptively by (1), where Qcbdenotes the current block $\mathrm{Q}\mathrm{P}, T_{pred}$ denotes the predicted texture complexity based on the neighboring reconstruction pixels, and parameters $\delta, Q_{jnd}, Q_{thres}$ and Tthresare preseted on the encoder and decoder side. So no additional syntax need to be transmitted in the bitstream. Moreover, for the transformation-off non-pixel-wise prediction, the straightforward extension of the PWQ method is designed to divide the coding block into simple and complex areas based on the above reference pixels, and reduce the pixel QP in simple areas. Qualitative results in Fig. 1 show that, the PWQ method can significantly improve the subjective quality by reducing the distortions on simple pixels, especially in the flat areas near the object edge and between the words on the screen content, and realizes more fine-grained pixel-level quantization compared with the traditional block-level quantization.

Federated learning (FL) has emerged as a paradigm to train a global machine learning model in a distributed manner while taking privacy concerns and data protection regulations into consideration. Although a variety of FL algorithms have been proposed, the training efficiency of FL remains challenging due to massive mathematical computations and expensive client-server communication costs. However, existing FL-acceleration studies are limited as they can only solve the computation and communication overheads separately, which is suboptimal and constrains their acceleration ability. Moreover, previous studies are typically designed for specific FL scenarios and can support only one or two FL models, thus exhibiting poor generality.To fill these critical voids, we propose FLBooster, which provides unified and efficient acceleration capacity for a broad range of FL models. This is the first proposal to solve the computation and communication overheads simultaneously. Specifically, we utilize GPUs to boost the computation-intensive homomorphic encryption (HE) operations in a parallel manner, which significantly reduces the computation costs. On the other hand, a simple but efficient compression method is designed to lighten the exchange of data volumes between client and server. Extensive experiments using four standard FL models on three datasets show that FLBooster acquires superior speed-up gains (i.e., 14.3× – 138×) over state-of-the-art acceleration systems. Finally, we integrate FLBooster into the open-source FL benchmark FATE and offer user-friendly APIs for development.

Network embedding, a graph representation learning method illustrating network topology by mapping nodes into lower-dimension vectors, is challenging to accommodate the ever-changing dynamic graphs in practice. Existing research is mainly based on node-by-node embedding modifications, which falls into the dilemma of efficient calculation and accuracy. Observing that the embedding dimensions are usually much smaller than the number of nodes, we break this dilemma with a novel dynamic network embedding paradigm that rotates and scales the axes of embedding space instead of a node-by-node update. Specifically, we propose the Dynamic Adjacency Matrix Factorization (DAMF) algorithm, which achieves an efficient and accurate dynamic network embedding by rotating and scaling the coordinate system where the network embedding resides with no more than the number of edge modifications changes of node embeddings. Moreover, a dynamic Personalized PageRank is applied to the obtained network embeddings to enhance node embeddings and capture higher-order neighbor information dynamically. Experiments of node classification, link prediction, and graph reconstruction on different-sized dynamic graphs suggest that DAMF advances dynamic network embedding. Further, we unprecedentedly expand dynamic network embedding experiments to billion-edge graphs, where DAMF updates billion-level parameters in less than 10ms.

Graph Neural Networks (GNNs) have been a powerful tool to acquire high-quality node representations dealing with graphs, which strongly depends on a promising graph structure. In the real world scenarios, it is inevitable to introduce noises in graph topology. To prevent GNNs from the disturbance of irrelevant edges or missing edges, graph structure learning is proposed and has attracted considerable attentions in recent years. In this paper, we argue that current graph structure learning methods still pay no regard to the status of nodes and just judge all of their connections simultaneously using a monotonous standard, which will lead to indeterminacy and instability in the optimization process. We designate these methods as status-unaware models. To demonstrate the rationality of our point of view, we conduct exploratory experiments on publicly available datasets, and discover some exciting observations. Afterwards, we propose a new model named Graph Structure Learning via Progressive Strategy (PROSE) according to the observations, which uses a progressive strategy to acquire ideal graph structure in a status-aware way. Concretely, PROSE consists of progressive structure splitting module (PSS) and progressive structure refining module (PSR) to modify node connections according to their global potency, and we also introduce horizontal position encoding and vertical position encoding in order to capture fruitful graph topology information ignored by previous methods. On several widely-used graph datasets, we conduct extensive experiments to demonstrate the effectiveness of our model, and the source code 1 https://github.com/tigerbunny2023/PROSE is provided.

Network data in real-world is error-prone, which results in inaccurate results when performing network analysis or modeling such as node classification and link prediction on these flawed networks. In this paper, we target at reconstructing a reliable network from a flawed network, named as network enhancement. Specifically, network enhancement aims to both detect the noisy links which are observed in the network but should not exist in the real world, and predict the missing links that indeed exist in the real world yet being unobserved in the network. Different from existing works that calculate a unified score to measure the above two kinds of links, we propose E-Net, an end-to-end graph neural network model, to leverage the mutual influence of the two tasks to achieve both the goals more effectively. Because on one hand, detecting noisy links can benefit the performance of predicting missing links; and on the other hand, predicting missing links can provide indirect supervision for detecting noisy links when the labels of the noisy links are unavailable. The experimental results on several datasets show that the proposed model obtains significant improvement for predicting missing links and detecting noisy links.

Multi-turn dialogue system has attracted increasing attention in both academic and industry community. Multi-turn dialogue generation task is a challenging work as the relations among words, utterances and external knowledge are extremely complex. However, the existing methods only focus on constructing the relations between current utterance and historical utterances, and they even oversimplify the relation mining process. Moreover, with the accumulation of dialogue information, the deep semantic information is difficult to understand so that it needs a mechanism with the ability of reasoning and digesting information repeatedly, which is ignored by previous methods. In order to solve the above problems, we propose a Memory Graph with Message Rehearsal (MGMR) for dialogue generation based on the cognitive process of human memory. MGMR contains three main modules: sensory memory, short-term memory and long-term memory. Sensory memory converts the current utterance into embeddings from both word-level and sentence-level. We design a message rehearsal module in short-term memory to extract valuable information of current utterance deeply and repeatedly combined with the relative historical dialogue information and external knowledge stored in long-term memory. Furthermore, we innovatively design a memory graph in long-term memory to construct the relations among words, utterances and knowledge. The memory graph achieves three goals: extracting accurate relations between current utterance and historical utterances, updating the historical dialogue information, and achieving knowledge precipitation by expanding memory graph with the key words and relevant external knowledge of current utterance. We evaluate our model on real-world datasets and achieve better performance compared with the existing state-of-the-art methods.

While Graph Neural Networks (GNNs) have become de facto criterion in graph representation learning, they still suffer from label scarcity and poor generalization. To alleviate these issues, graph pre-training has been proposed to learn universal patterns from unlabeled data via applying self-supervised tasks. Most existing graph pre-training methods only use a single self-supervised task, which will lead to insufficient knowledge mining. Recently, there are also some works that try to use multiple self-supervised tasks, however, we argue that these methods still suffer from a serious problem, which we call it graph structure impairment. That is, there actually exists structural gaps among several tasks due to the divergence of optimization objectives, which means customized graph structures should be provided for different self-supervised tasks. Graph structure impairment not only significantly hurts the generalizability of pre-trained GNNs, but also leads to suboptimal solution, and there is no study so far to address it well. Motivated by Meta-Cognitive theory, we propose a novel model named Core Graph Cognizing and Differentiating (CORE) to deal with the problem in an effective approach. Specifically, CORE consists of cognizing network and differentiating process, the former cognizes a core graph which stands for the essential structure of the graph, and the latter allows it to differentiate into several task-specific graphs for different tasks. Besides, this is also the first study to combine graph pre-training with cognitive theory to build a cognition-aware model. Several experiments have been conducted to demonstrate the effectiveness of CORE.

Travel time prediction is a critical task in intelligent transportation system and location-based service. Existing studies build models based on the features extracted from trajectories, but few of them consider the sparsity of trajectory data from both temporal and spatial dimensions, as well as the spatial structure and heterogeneity. To address these issues, we propose a novel Multi-scale spatial-temporal model for Travel Time Prediction, abbreviated as MTTPRE. Specifically, the study area is represented as a flexible Voronoi graph according to a variable-sized partition scheme and the missing features on it are recovered via a spatial-temporal context-based method. Subsequently, a geospatial network with POI information is established to represent the spatial structure based on the Voronoi graph. Next, the multi-dimensional traffic condition features and graph-trajectory-POI multilevel features are extracted as spatial-temporal features. Finally, these features are fed into a hierarchical multi-task learning layer to complete the travel time prediction task. Extensive experiments on two real-world datasets show that the MTTPRE outperforms all the competitors with significant improvement and remarkable robustness.

Chart classification is the foundation of chart analysis and document understanding. In this paper, we propose a novel framework to classify charts by combining convolutional networks and deep belief networks. In the framework, we firstly extract deep hidden features of charts, which are taken from the fully-connected layer of deep convolutional networks. We then utilize deep belief networks to predict the labels of the charts based on their deep hidden features. The convolutional networks are initialized using a large number of natural images and fine-tuned using the chart images to prevent overfitting. Compared with previous methods using primitive feature extraction, the deep features give our framework better scalability and stability. We collect a 5-class chart dataset with more than 5000 images and show that the proposed framework outperforms existing methods greatly.