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Xuejun Li

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3 papers

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JBHI Journal 2023 Journal Article

Contrastive Learning for Prediction of Alzheimer's Disease Using Brain 18F-FDG PET

Yonglin Chen
Huabin Wang
Gong Zhang
Xiao Liu
Wei Huang
Xianjun Han
Xuejun Li
Melanie Martin

Brain 18F-FDG PET images are commonly-known materials for effectively predicting Alzheimer's disease (AD). However, the data volume of PET is usually insufficient, which is unfavorable to train an accurate AD prediction networks. Furthermore, the PET image is noisy with low signal-to-noise ratio, and simultaneously the feature (metabolic abnormality) used for predicting AD in PET image is not always obvious. Therefore, a contrastive-based learning method is proposed to address the challenges of PET image inherently possessed. Firstly, the slices of 3D PET image are amplified by cropping the image of anchors (i. e. , an augmented version of the same image) to generate extended training data. Meanwhile, contrastive loss is adopted to enlarge inter-class feature distances and reduce intra-class feature differences using subject fuzzy labels as supervised information. Secondly, we construct a double convolutional hybrid attention module to enhance the network to learn different perceptual domains where two convolutional layers with different convolutional kernels ( $7\times 7$ and $5\times 5$ ) are constructed. Moreover, we recommend a diagnosis mechanism by analyzing the consistency of predicted result for PET slices alone with clinical neuropsychological assessment to achieve a better AD diagnosis. The experimental results show that the proposed method outperforms the state-of-the-arts for brain 18F-FDG PET images, and hence demonstrate the advantage of the method in effectively predicting AD.

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AAAI Conference 2021 Conference Paper

Tri-level Robust Clustering Ensemble with Multiple Graph Learning

Peng Zhou
Liang Du
Yi-Dong Shen
Xuejun Li

Clustering ensemble generates a consensus clustering result by integrating multiple weak base clustering results. Although it often provides more robust results compared with single clustering methods, it still suffers from the robustness problem if it does not treat the unreliability of base results carefully. Conventional clustering ensemble methods often use all data for ensemble, while ignoring the noises or outliers on the data. Although some robust clustering ensemble methods are proposed, which extract the noises on the data, they still characterize the robustness in a single level, and thus they cannot comprehensively handle the complicated robustness problem. In this paper, to address this problem, we propose a novel Tri-level Robust Clustering Ensemble (TRCE) method by transforming the clustering ensemble problem to a multiple graph learning problem. Just as its name implies, the proposed method tackles robustness problem in three levels: base clustering level, graph level and instance level. By considering the robustness problem in a more comprehensive way, the proposed TRCE can achieve a more robust consensus clustering result. Experimental results on benchmark datasets also demonstrate it. Our method often outperforms other state-ofthe-art clustering ensemble methods. Even compared with the robust ensemble methods, ours also performs better.

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IJCAI Conference 2020 Conference Paper

Self-paced Consensus Clustering with Bipartite Graph

Peng Zhou
Liang Du
Xuejun Li

Consensus clustering provides a framework to ensemble multiple clustering results to obtain a consensus and robust result. Most existing consensus clustering methods usually apply all data to ensemble learning, whereas ignoring the side effects caused by some difficult or unreliable instances. To tackle this problem, we propose a novel self-paced consensus clustering method to gradually involve instances from more reliable to less reliable ones into the ensemble learning. We first construct an initial bipartite graph from the multiple base clustering results, where the nodes represent the instances and clusters and the edges indicate that an instance belongs to a cluster. Then, we learn a structured bipartite graph from the initial one by self-paced learning, i. e. , we automatically decide the reliability of each edge and involves the edges into graph learning in order of their reliability. At last, we obtain the final consensus clustering result from the learned bipartite graph. The extensive experimental results demonstrate the effectiveness and superiority of the proposed method.

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