Kernel power k-means (KPKM) leverages a family of means to mitigate local minima issues in kernel k-means. However, KPKM faces two key limitations: (1) the computational burden of the full kernel matrix restricts its use on extensive data, and (2) the lack of authentic centroid-sample assignment learning reduces its noise robustness. To overcome these challenges, we propose RFF-KPKM, introducing the first approximation theory for applying random Fourier features (RFF) to KPKM. RFF-KPKM employs RFF to generate efficient, low dimensional feature maps, bypassing the need for the whole kernel matrix. Crucially, we are the first to establish strong theoretical guarantees for this combination: (1) an excess risk bound of O( k^3/n), (2) strong consistency with membership values, and (3) a (1 + ε) relative error bound achievable using the RFF of dimension poly(ε^{−1} logk). Furthermore, to improve robustness and the ability to learn multiple kernels, we propose IP-RFF-MKPKM, an improved possibilistic RFF-based multiple kernel power k-means. IP-RFF-MKPKM ensures the scalability of MKPKM via RFF and refines cluster assignments by combining the merits of the possibilistic and fuzzy membership. Experiments on large-scale datasets demonstrate the superior efficiency and clustering accuracy of the proposed methods compared to the state-of-the-art alternatives.

Clustering is a fundamental task in unsupervised learning, but most existing methods heavily rely on hyperparameters such as the number of clusters or other sensitive settings, limiting their applicability in real-world scenarios. To address this long-standing challenge, we propose a novel and fully parameter-free clustering framework via Self-supervised Consensus Maximization, named SCMax. Our framework performs hierarchical agglomerative clustering and cluster evaluation in a single, integrated process. At each step of agglomeration, it creates a new, structure-aware data representation through a self-supervised learning task guided by the current clustering structure. We then introduce a nearest neighbor consensus score, which measures the agreement between the nearest neighbor-based merge decisions suggested by the original representation and the self-supervised one. The moment at which consensus maximization occurs can serve as a criterion for determining the optimal number of clusters. Extensive experiments on multiple datasets demonstrate that the proposed framework outperforms existing clustering approaches designed for scenarios with an unknown number of clusters.

Temporal graph learning focuses on graph deep learning in real-world dynamic scenarios, which uses interaction sequence instead of adjacency matrix to observe the graph dynamic changes more microscopically from the perspective of time evolution. However, current temporal graph methods only focus on extra dynamic information, ignoring the large amount of multi-modal information contained in the real world. These information can reflect the rich changes in the real world from different perspectives. Ignoring them means that temporal graph learning still lacks the ability to restore and mine more complex real-world data. We argue that the main challenges causing the above phenomenon in temporal graph learning are the lack of multi-modal architecture and public multi-modal datasets. To solve the above challenges, we propose ModalTGL, which enhances the computational efficiency of the model in complex dynamic scenarios by introducing the dictionary graph network, and achieves multi-modal fusion by embedding tuning. In addition, we also discuss the effects of different time encoding functions on dynamic information preservation. At the data level, we build several multi-modal temporal graph datasets from different areas, and compare with multiple SOTA methods on these datasets. The experimental results verify the effectiveness of the ModalTGL method, achieving the performance improvement of up to 18.48%.

Multi-view clustering aims to leverage complementary information from multiple data sources to improve clustering quality. Traditional graph-based Non-k multi-view clustering methods enable automatic cluster number determination but suffer from severe scalability issues due to their reliance on constructing large sample-level affinity graphs with quadratic complexity. To address this limitation, we propose a novel scalable Non-k Multi-View Clustering framework via Inter-Anchor Graph learning (MVC-IAG). Our method first extracts a small set of representative anchors via k-means on concatenated multi-view features, then learns a unified inter-anchor graph by integrating multi-view structural information and feature similarity priors. Our framework performs Non-k cluster discovery directly on this compact, learned inter-anchor graph, thereby enabling automatic cluster number determination, and subsequently propagates the results to all samples. Extensive experiments on multiple large scale datasets demonstrate that MVC-IAG significantly reduces computational cost while achieving competitive or superior clustering performance compared to state-of-the-art Non-k multi view clustering approaches.

Graph neural networks (GNNs) have achieved remarkable success, yet most are developed under the in-distribution assumption and fail to generalize to out-of-distribution (OOD) environments. To tackle this problem, some graph invariant learning methods aim to learn invariant subgraph against distribution shifts, which heavily rely on predefined or automatically generated environment labels. However, directly annotating or estimating such environment labels from biased graph data is typically impractical or inaccurate for real-world graphs. Consequently, GNNs may become biased toward variant patterns, resulting in poor OOD generalization. In this paper, we propose to learn disentangled invariant subgraph via self-supervised contrastive variant subgraph estimation for achieving satisfactory OOD generalization. Specifically, we first propose a GNN-based invariant subgraph generator to disentangle the invariant and variant subgraphs. Then, we estimate the degree of the spurious correlations by conducting self-supervised contrastive learning on variant subgraphs. Thanks to the accurate identification and estimation of the variant subgraphs, we can capture invariant subgraphs effectively and further eliminate spurious correlations by inverse propensity score reweighting. We provide theoretical analyses to show that our model can disentangle the ground-truth invariant and variant subgraphs for OOD generalization. Extensive experiments demonstrate the superiority of our model over state-of-the-art baselines.

Multi-view bipartite graph clustering (MVBGC) is an active pipeline in unsupervised learning to tackle the limited scalability issue of traditional graph clustering. Despite improved performance, numerous variants still fall under conventional modeling that plugs additional modules, which however induces increasingly intricate models and fails to reveal the inherent variable relationship. We make the first attempt to introduce probabilistic graphical models for modeling the multi-view bipartite graph clustering task, reformulating it as a maximum likelihood estimation (MLE) problem. Such a setting uncovers the underlying probabilistic correlations among the commonality, view-specific variables, and noisy components. By pruning redundancy and disturbance collectively referred to as noise, we prove that minimizing the total noise is an approximation of the lower bound of MLE for multi-view data observations. We further generalize the MLE setting with clustering-suited constraints, deriving a Generalized Probabilistic Graphical Modeling framework (GProM), achieving an interpretable, concise, and flexible MVBGC framework. Extensive experiments verify the effectiveness of our framework. Furthermore, statistical significance analysis reveals the effectiveness of different distribution assumptions, providing valuable insights for model design.

In recent years, multi-view unsupervised feature selection has gained significant interest for its ability to efficiently handle multi-view datasets while offering better interpretability. Existing multi-view unsupervised feature selection methods construct graphs based on the relationship between samples. In fact, in feature selection, it is more important to focus on the relationships between features. However, constructing a complete graph to capture the relationship between features would incur a space and time complexity of $O(d^{2})$ or even higher. Therefore, we introduce an anchor-based strategy and build a feature bipartite graph to reduce complexity. In addition, since existing methods cannot directly extract feature importance from a feature bipartite graph, we design an effective and low-complexity method to directly obtain feature scores from a feature bipartite graph. Compared with the feature importance extraction method based on the complete graph, our proposed method reduces the time complexity from $O(d^{3})$ to $O(d)$ . To the best of our knowledge, our proposed method is the first multi-view unsupervised feature selection algorithm that achieves $O(nd)$ space and time complexity without data segmentation. Specifically, this method adaptively learns feature-level anchor graph structures through self-expressive multi-view subspace learning, which can effectively capture the structural information between features and anchors. Meanwhile, the proposed method projects low-dimensional anchors to common dimensions and aligns them with consensus anchors to capture the consistency and complementary information between different views. The superiority of the proposed algorithm is demonstrated by comparing it with seven state-of-the-art algorithms on five public image and two biological information multi-view datasets. The code of the proposed method is publicly available at https://github.com/getupLiu/AFRC.

Concept decomposition is a technique for personalized text-to-image synthesis which learns textual embeddings of subconcepts from images that depicting an original concept. The learned subconcepts can then be composed to create new images. However, existing methods fail to address the issue of contextual conflicts when subconcepts from different sources are combined because contextual information remains encapsulated within the subconcept embeddings. To tackle this problem, we propose a Context-aware Concept Decomposition ($C^{2}D$C2D) framework. Specifically, we introduce a Similarity-Guided Divergent Embedding (SGDE) method to obtain subconcept embeddings. Then, we eliminate the latent contextual dependence between the subconcept embeddings and reconstruct the contextual information using an independent contextual embedding. This independent context can be combined with various subconcepts, enabling more controllable text-to-image synthesis based on subconcept recombination. Extensive experimental results demonstrate that our method outperforms existing approaches in both image quality and contextual consistency.

Biometric authentication is up-and-coming to replace the traditional identity authentication method (e.g., passwords, PIN, identification cards) for its convenience and intelligence. With more and more users using this method, the database becomes more extensive, and the functions are seriously challenged. Data outsourcing has advantages in terms of convenience and cost savings, so it has attracted much research effort. However, due to the biometric's immutability of the whole life, it is extremely sensitive, and disclosing it to a third party is undesirable. In this paper, we address the issue of securely outsourcing biometric database. We propose a novel boolean searchable symmetric encryption (SSE) to construct a secure interactive protocol when outsourcing. A new encrypted database construction method was proposed, using the more efficient boolean vectors. Based on this, We suggest three kinds of expressive SSE, supporting disjunctive query, boolean query, and lightweight settings. We prove the schemes' correctness and security theoretically. Our constructions use simple cryptographic tools, such as symmetric cryptography and pseudo-random functions. They are straightforward to understand and easy to implement. The experiments show that all our schemes are practical and more efficient than the existing methods.