Scalable one-stage multi-view subspace clustering with dictionary learning

The clustering of large numbers of heterogeneous features is a hot topic in multi-view communities. Most existing multi-view clustering (MvC) methods employ matrix factorization or anchor strategies to handle large-scale datasets. The former operates on the original data and is, therefore, sensitive to noise and feature redundancy, which is reflected in the final clustering performance. The latter requires post -processing steps to generate the clustering results, which may be suboptimal owing to the isolation steps. To address the above problems, we propose one-stage multi-view subspace clustering with dictionary learning (OSMvSC). Specifically, we integrate dictionary learning, representation coefficient matrix learning, and matrix factorization as a unified learning framework, which directly learns the dictionary and representation coefficient matrix to encode the original multi-view data, and obtains the clustering results with linear time complexity without any postprocessing step. By manipulating the class centroid with the nuclear norm, a more compact and discriminative class centroid representation can be obtained to further improve clustering performance. An effective optimization algorithm with guaranteed convergence is designed to solve the proposed method. Substantial experiments on various real-world multi-view datasets demonstrate the effectiveness and superiority of the proposed method. The source code is available at https://github.com/justcallmewilliam/OSMvSC.(c) 2022 Elsevier B.V. All rights reserved.

Detection of COVID-19 in X-Ray Images Using Constrained Multi-view Spectral Clustering

Machine learning, and specifically classification algorithms, has been widely used for the diagnosis of COVID-19 cases. However, these methods require knowing the labels of the datasets, and use a single view of the dataset. Due to the widespread of the COVID-19 cases, and the presence of the huge amount of patient datasets without knowing their labels, we emphasize in this paper to study, for the first time, the diagnosis of COVID-19 cases in an unsupervised manner. Thus, we can benefit from the abundance of datasets with missing labels. Nowadays, multi-view clustering attracts many interests. Spectral clustering techniques have attracted more attention thanks to a well-developed and solid theoretical framework. One of the major drawbacks of spectral clustering approaches is that they only provide a nonlinear projection of the data, which requires an additional clustering step. Since this post-processing step depends on numerous factors such as the initialization procedure or outliers, this can affect the quality of the final clustering. This paper provides an improved version of a recent method called Multiview Spectral Clustering via integrating Nonnegative Embedding and Spectral Embedding. In addition to keeping the benefits of this method, our proposed model incorporates two types of constraints: (i) a consistent smoothness of the nonnegative embedding across all views, and (ii) an orthogonality constraint over the nonnegative embedding matrix columns. Its advantages are demonstrated using COVIDx datasets. Besides, we test it with other image datasets to prove the right choice of this method in this study. © 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG.