Federated heterogeneous graph learning, an extension of federated learning, effectively represents complex multidimensional relationships while maintaining data privacy. In horizontal federated heterogeneous graph learning, data from different parties often vary in topology and semantics, leading to sensitivity to distribution imbalances and increasing topological complexity. These differences hinder models from learning shared representations and cause instability during training. To address these challenges, this paper proposes a novel multi-scale adaptive horizontal federated heterogeneous graph learning method MAFedHGL. A random masking mechanism forces the model to infer missing connections. The model also captures multi-hop and multi-path connections using high-order topology mining, enhancing robustness against structural heterogeneity. Dynamic semantic consistency modeling uses a masking matrix to recover and integrate diverse node attributes, ensuring both global and local semantic consistency. Using clustering coefficients as aggregation weights enables clients with richer structural information to contribute more effectively to the global model, improving adaptability and performance across varying data distributions in horizontal federated heterogeneous graph learning. Extensive experiments on multiple public heterogeneous graph datasets validate that the proposed method outperforms state-of-the-art methods in both performance and robustness across various data distribution scenarios.

Cross-media hash retrieval are efficient and effective techniques for retrieval on multi-media database. The success of the Multimodal Large Models (MLM) provides a valuable direction to enhance the accuracy of multimodal hash retrieval, which achieves decent retrieval accuracy with finetuning the pretrained multimodal large models, but their massive model parameters significantly reduce retrieval efficiency. Knowledge Distillation (KD) methods enable small models to learn from the knowledge of larger models, achieving a reduction in model parameter count while ensuring a certain level of accuracy. However, current KD methods face challenges when applied in the multimodal domain, as it requires preserving the multimodal semantic information while minimizing accuracy degradation. To address these challenges, we propose a novel unsupervised multimodal graph contrastive semantic anchor space dynamic knowledge distillation network for cross-media hash retrieval (GASKN). Firstly, to obtain a multimodal semantic anchor space, we construct a large multimodal fusion teacher model using the BEiT-3 model as the backbone. This teacher model is capable of encoding data from different modalities, such as images and text, using the same multimodal encoder to acquire multimodal hash codes that contain rich information from both modalities simultaneously. Secondly, to ensure efficient retrieval capabilities for the student model, we utilize the ALBERT text encoding model and the BiFormer image encoding model as the compact student model's backbones. This allows us to build a lightweight student model with only a twentieth of the parameter count of the teacher model. We propose a dynamic knowledge distillation technique to transfer the multimodal semantic anchor space knowledge embedded in the multimodal large teacher model to the lightweight student model as much as possible. Thirdly, to further distill the structural knowledge of the semantic anchor space from the teacher model to the student model, we propose a graph attention contrastive learning mechanism, which enables structural semantic space learning, thereby mining implicit fine-grained cross-media semantic information. By evaluating our method using three widely-used datasets, we demonstrate that GASKN is able to significantly outperform existing state-of-the-art hashing algorithms.

Image-text retrieval is a fundamental cross-modal task that aims to align the representation spaces between the image and text modalities. Existing cross-modal image-text retrieval methods independently generate embeddings for images and text, introduce interaction-based networks for cross-modal inference, and then achieve retrieval by using matching metrics. However, they overlook the semantic relationship between the coarse-grained and fine-grained representations within each modality, failing to capture the consistency of representations across different modalities, which affects the semantic learning of cross-modal representations, and makes it difficult to align modalities in semantic space. Consequently, these previous works inevitably suffer from low retrieval accuracy or high computational costs. In this paper, instead of directly fusing two cross-modal het-erogeneous spaces, we propose an multimodal knowledge enhanced multimodal transformer network framework to combine coarse-grained and fine-grained representation learning into a unified framework, capturing alignment information between targets, constructing a global semantic graph, and ultimately align multimodal representations in the semantic space. In our approach, images generate semantic and spatial graphs to represent visual information, while sentences generate text graphs based on semantic relationships between words, and they are used for intra-modal graph network inference. Subsequently, the generated global and local embeddings are fused into an enhanced multimodal transformer framework, effectively imple-menting cross-modal interaction processes by leveraging prior implicit semantic information from the multimodal knowledge graph. Furthermore, compared to simply matching words with image regions, our method proposes a bidirectional fine-grained matching method to filter the salient regions and words of images and texts, remove the interfering noise information, and realize bidirectional fine-grained pairing, which captures fine-grained bi-directional representational information, thus enable the model to generate more discriminative representations Finally, equipped with a coarse-to-fine inference method based on hybrid global and local cross-modal similarities, we demonstrate that the proposed method is able to significantly outperform existing state-of-the-art algorithms by evaluating our method using two widely-used datasets.

During the training process of federated learning models, the domain information of the target test data on the server can differ greatly from the training data of each client, leading to a decrease in the performance of the federated model. Additionally, due to privacy protection during federated training, clients cannot see the target domain test data, and the distribution information of the target data cannot be used. This poses a new challenge for federated learning. Domain generalization techniques are often used in centralized frameworks to resolve such problems. In recent years, the domain generalization method based on feature decorrelation has enabled models to learn knowledge with a stronger generalization ability in unseen target domain data. However, existing methods require data centralization in the feature decorrelation process, which conflicts with data privacy protection in federated learning. To address these issues, we propose Reinforcement Federated Domain Generalization (RFDG), which incorporates domain generalization in federated learning via reinforcement learning. RFDG can improve the generalization ability of the federated model of unseen target domain test data. We design a reinforcement federated feature decorrelation policy that uses reinforcement learning technology to transform the sample reweight work into a parameterized sample reweight policy that can be shared among federated learning clients. We develop reinforcement federated experience replay techniques to supplement the feature information loss of local data due to the mini-batch mechanism during the policy learning process. When the policy is shared by each client, those features can be decorrelated from a global perspective, allowing the model to focus on capturing the fundamental association between features and labels to learn domain-invariant knowledge. We verified the effectiveness of our method through extensive experiments using four publicly available datasets.

Deep cross-media hashing provides an efficient semantic representation learning solution for large-scale cross-media retrieval. The existing methods only consider the inter-media or intra-media semantic association learning, ignore the guiding of semantic structure information, and have weak reasoning ability for implicit fine-grained semantic associations. To tackle this problem, we propose a novel structures aware fine-grained contrastive adversarial hashing method for cross-media retrieval. A novel cross-media contrastive adversarial hash network is constructed for the first time, which integrates the cross-media and intra-media contrastive learning and multi-modal adversarial learning, aiming at maximizing the semantic association between different modalities, and improving the semantic discrimination and consistency of cross-media unified hash representation, thereby the inter-media and intra-media semantic preserving ability can be well enhanced; A fine-grained cross-media semantic feature learning method based on fine-grained semantic reasoning with transformers is proposed, which captures fine-grained salient features of different modalities for semantic association learning, and enhances the reasoning ability of fine-grained implicit semantic association; A semantic label graph convolutional network guided cross-media semantic association learning strategy is proposed, which makes full use of semantic structure information to enhance the learning ability of implicit cross-media semantic associations. Extensive experiments on several large-scale cross-media benchmark datasets demonstrate that the proposed method outperforms the state-of-the-art methods.

Video super-resolution (SR) reconstruction technology aims at obtaining high quality reconstruction of high-resolution (HR) video sequences by inferring the lost detailed information from their low-resolution (LR) counterparts. However, this technology is an ill-posed problem because significant detailed information is lost in the process of video degrading. The existing learning-based SR reconstruction methods can be adapted to a larger super-resolution factor, but it cannot be guaranteed that any low-resolution image block can find its corresponding high-resolution block matching in a limited-scale training set. Some noise and over smooth phenomenon usually exist while dealing with some unique features that rarely appear in a given training data set. The self-similarity based SR methods do not rely on accurate sub-pixel motion estimation and thus can be adapted to complex motion patterns. However, under conditions of insufficient internal similar blocks, some visual flaws are usually produced due to the mismatched internal instances.

In recent years, the issue of data privacy has attracted more and more attention. Federated learning is a practical solution to train the model while guaranteeing data privacy. It has two main characteristics: the first is that the data in the clients is usually non-IID, and the second is that the data of each client cannot be shared. However, due to the non-IID data of each client, the optimal solution of the client is often inconsistent with the global optimal solution. The non-IID data often causes the client to optimize along the local optimal direction and drift out of the global optimal solution during training. Due to the client drift problem, the server tends to converge slowly so that the overall communication efficiency of federated learning is usually limited. To improve the communication efficiency of federated learning, in this paper, we propose a new federated learning framework which integrates multi-level prospective correction factor in the training procedure of server and clients. We propose the global prospective correction factor in server aggregation to reduce model communication rounds and accelerate convergence. In client training, we introduce the local prospective correction factor to alleviate client drift. Both global and local prospective correction factors are integrated into a unified federated learning framework to further improve the communication efficiency. Extensive experiments conducted on several datasets demonstrate that our method can effectively improve the communication efficiency and is robust to different federated learning environments.

This paper studies the distributed federated learning problem when the exchanged information between the server and the workers is quantized. A novel quantized federated averaging algorithm is developed by applying stochastic quantization scheme to the local and global model parameters. Specifically, the server broadcasts the quantized global model parameter to the workers; the workers update local model parameters using their own data sets and upload the quantized version to the server; then the server updates the global model parameter by aggregating all the quantized local model parameters and its previous global model parameter. This algorithm can be interpreted as a quantized variant of the federated averaging algorithm. The convergence is analyzed theoretically for both convex and strongly convex loss functions with Lipschitz gradient. Extensive experiments using realistic data are provided to show the effectiveness of the proposed algorithm.

Predicting the development trend of future scientific research not only provides a reference for researchers to understand the development of the discipline, but also provides support for decision-making and fund allocation for decision-makers. The continuous growth of scientific publications has brought challenges to track the development trends of scientific research topics. The existing topic trend prediction methods have proved that the research topic trend of a publication is influenced by other peer publications. However, they ignore the fact that the research topics of different publications belong to different research topic space. Moreover, the existing topic prediction methods do not fully consider the interactive influence among publications that the research topic of one publication affects the topics of other publications, it is also influenced by the research topics of other publications. In line with this, this paper proposes a scientific research topic trend prediction model based on multi-long short-term memory (multi-LSTM) and Graph Convolutional Network. Specifically, multiple LSTMs are employed to map research topics of different publications into their respective topic space. Then, the graph convolutional neural network is applied to learn the scientific influence context of each publication, so that the research topic of each publication not only integrates the influence of neighbor nodes, but also considers the influence of the neighbors of the neighbor node on the research topic of the publication, so as to more accurately fuse scientific influence context of research topic of peer publications. Experiments results on the data set of scientific research papers in the field of artificial intelligence and data mining demonstrate that the model improves the prediction precision and achieves the state-of-the-art research topic trend prediction effect compared with the other baseline models.

To address the problems in the existing video super-resolution methods, such as noise, over smooth and visual artifacts, which are caused by the reliance on limited external training or mismatch of internal similarity patch instances, this study proposes a novel video super-resolution reconstruction algorithm based on deep learning and spatio-temporal feature similarity (DLSS-VSR). The video super-resolution reconstruction mechanism with the joint internal and external constraints is established utilizing the complementary advantages of both external deep correlation mapping learning and internal spatio-temporal nonlocal self-similarity prior constraint. A deep learning model based on deep convolutional neural network is constructed to learn the nonlinear correlation mapping between low-resolution and high-resolution video frame patches. A novel spatio-temporal feature similarity calculation method is proposed, which considers both internal video spatio-temporal self-similarity and external clean nonlocal similarity. For the internal spatio-temporal feature self-similarity, we improve the accuracy and robustness of similarity matching by proposing a similarity measure strategy based on spatio-temporal moment feature similarity and structural similarity. The external nonlocal similarity prior constraint is learned by the patch group-based Gaussian mixture model. The time efficiency for spatio-temporal similarity matching is further improved based on saliency detection and region correlation judgment strategy, which achieves a better tradeoff between super-resolution accuracy and speed. Experimental results demonstrate that the DLSS-VSR algorithm achieves competitive super-resolution quality compared to other state-of-the-art algorithms in both subjective and objective evaluations.

Social networks are critical sources for event detection thanks to the characteristics of publicity and dissemination. Unfortunately, the randomness and semantic sparsity of the social network text bring significant challenges to the event detection task. In addition to text, time is another vital element in reflecting events since events are often followed for a while. Therefore, in this article, we propose a novel method named Multi-View Graph Attention Network (MVGAN) for event detection in social networks. It enriches event semantics through both neighbor aggregation and multi-view fusion in a heterogeneous social event graph. Specifically, we first construct a heterogeneous graph by adding the hashtag to associate the isolated short texts and describe events comprehensively. Then, we learn view-specific representations of events through graph convolutional networks from the perspectives of text semantics and time distribution, respectively. Finally, we design a hashtag-based multi-view graph attention mechanism to capture the intrinsic interaction across different views and integrate the feature representations to discover events. Extensive experiments on public benchmark datasets demonstrate that MVGAN performs favorably against many state-of-the-art social network event detection algorithms. It also proves that more meaningful signals can contribute to improving the event detection effect in social networks, such as published time and hashtags.