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Bayesian compressive principal component analysis

Frontiers of Computer Science 2020年第4期14卷 29-38页

作者： Di MA Songcan CHEN College of Computer Science and Technology Nanjing University of Aeronautics and AstronauticsNanjing211106China College of Computer Science and Technology Nanjing University of Aeronautics and AstronauticsMIIT Key Laboratory of Pattern Analysis and Machine IntelligenceNanjing211106China

Principal component analysis(PCA)is a widely used method for multivariate data analysis that projects the original high-dimensional data onto a low-dimensional subspace with maximum ***,in practice,we would be more likely to obtain a few compressed sensing(CS)measurements than the complete high-dimensional data due to the high cost of data acquisition and *** this paper,we propose a novel Bayesian algorithm for learning the solutions of PCA for the original data just from these CS *** this end,we utilize a generative latent variable model incorporated with a structure prior to model both sparsity of the original data and effective dimensionality of the latent *** proposed algorithm enjoys two important advantages:1)The effective dimensionality of the latent space can be determined automatically with no need to be pre-specified;2)The sparsity modeling makes us unnecessary to employ multiple measurement matrices to maintain the original data space but a single one,thus being storage *** results on synthetic and real-world datasets show that the proposed algorithm can accurately learn the solutions of PCA for the original data,which can in turn be applied in reconstruction task with favorable results.

关键词： compressed sensing principal component analysis Bayesian learning sparsity modeling

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An Improved AdaBoost Method in Imbalanced Data Learning

An Improved AdaBoost Method in Imbalanced Data Learning

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2023 International Conference on Cyber-Physical Social intelligence, ICCSI 2023

作者： Li, Ting Chen, Xiaofeng Li, Weikai Chongqing Jiaotong University Department of Mathematics Chongqing China Miit Key Laboratory of Pattern Analysis and Machine Intelligence Nanjing China

ISBN: (纸本)9798350312492

Learning from imbalanced datasets has recently received increasing research attention. Despite the remarkable results of AdaBoost in balanced situation, the imbalance problem remains to be solved. To address this, this paper proposes a novel method to improve the AdaBoost using a new error factor and a weighted voting parameter for a few classes and weak classifiers. Our method can weaken the dominant role of the majority class in iterative training by improving the classification ability of the minority class. The superiority of the proposed algorithm is finally proved theoretically and practically. Several real-world imbalance datasets in experiments as specific support, and our method outperforms previous algorithms, especially in the F-1 metric. © 2023 IEEE.

关键词： Adaptive boosting

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Beyond Myopia: Learning from Positive and Unlabeled Data through Holistic Predictive Trends 37

Beyond Myopia: Learning from Positive and Unlabeled Data thr...

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37th Conference on Neural Information Processing Systems, NeurIPS 2023

作者： Wang, Xinrui Wan, Wenhai Geng, Chuanxing Li, Shaoyuan Chen, Songcan College of Computer Science and Technology Nanjing University of Aeronautics and Astronautics MIIT Key Laboratory of Pattern Analysis and Machine Intelligence China

ISBN: (纸本)9781713899921

Learning binary classifiers from positive and unlabeled data (PUL) is vital in many real-world applications, especially when verifying negative examples is difficult. Despite the impressive empirical performance of recent PUL methods, challenges like accumulated errors and increased estimation bias persist due to the absence of negative labels. In this paper, we unveil an intriguing yet long-overlooked observation in PUL: resampling the positive data in each training iteration to ensure a balanced distribution between positive and unlabeled examples results in strong early-stage performance. Furthermore, predictive trends for positive and negative classes display distinctly different patterns. Specifically, the scores (output probability) of unlabeled negative examples consistently decrease, while those of unlabeled positive examples show largely chaotic trends. Instead of focusing on classification within individual time frames, we innovatively adopt a holistic approach, interpreting the scores of each example as a temporal point process (TPP). This reformulates the core problem of PUL as recognizing trends in these scores. We then propose a novel TPP-inspired measure for trend detection and prove its asymptotic unbiasedness in predicting changes. Notably, our method accomplishes PUL without requiring additional parameter tuning or prior assumptions, offering an alternative perspective for tackling this problem. Extensive experiments verify the superiority of our method, particularly in a highly imbalanced real-world setting, where it achieves improvements of up to 11.3% in key metrics. The code is available at https://***/wxr99/HolisticPU. © 2023 Neural information processing systems foundation. All rights reserved.

关键词： Iterative methods

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An Improved Algorithm for Spiking Neural Networks with Multi-Scale Attention Coding

An Improved Algorithm for Spiking Neural Networks with Multi...

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2024 International Conference on Cyber-Physical Social intelligence, ICCSI 2024

作者： Chen, Sisi Chen, Xiaofeng Li, Weikai Chongqing Jiaotong University Department of Mathematics Chongqing China Miit Key Laboratory of Pattern Analysis and Machine Intelligence Nanjing China

ISBN: (纸本)9798350376739

Spiking Neural Networks (SNNs), driven by spike-based mechanisms, are known for their high efficiency and low energy consumption, which makes them ideal for applications like image classification, object detection, and medical diagnostics. However, challenges include training difficulties due to the non-differentiability of spiking activities and limitations in encoding schemes, which struggle to capture complex spatio-temporal dynamics. In this paper, we propose a novel algorithm, termed the Spatio-Temporal Backpropagation algorithm with Multi-Scale Attention Coding (STBP-MSC). STBP-MSC dynamically allocates attention across spatial and temporal domains, which improves coding efficiency and enhances the classification accuracy of SNNs. Furthermore, STBP-MSC incorporates the Complementary Leaky Integrate-and-Fire (CLIF) neuron model, which enhances temporal gradient computation. Experimental results on the MNIST and Fashion-MNIST datasets demonstrate that STBP-MSC achieves high coding efficiency and superior performance within minimal time windows. © 2024 IEEE.

关键词： Network coding

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Robust AUC maximization for classification with pairwise confidence comparisons

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Frontiers of Computer Science 2024年第4期18卷 73-83页

作者： Haochen SHI Mingkun XIE Shengjun HUANG College of Computer Science and Technology Nanjing University of Aeronautics and AstronauticsNanjing 211106China College of Electronic and Information Engineering Nanjing University of Aeronautics and AstronauticsNanjing 211106China MIIT Key Laboratory of Pattern Analysis and Machine Intelligence Nanjing 211106China

Supervised learning often requires a large number of labeled examples,which has become a critical bottleneck in the case that manual annotating the class labels is *** mitigate this issue,a new framework called pairwise comparison(Pcomp)classification is proposed to allow training examples only weakly annotated with pairwise comparison,i.e.,which one of two examples is more likely to be *** previous study solves Pcomp problems by minimizing the classification error,which may lead to less robust model due to its sensitivity to class *** this paper,we propose a robust learning framework for Pcomp data along with a pairwise surrogate loss called *** provides an unbiased estimator to equivalently maximize AUC without accessing the precise class ***,we prove the consistency with respect to AUC and further provide the estimation error bound for the proposed *** studies on multiple datasets validate the effectiveness of the proposed method.

关键词： method pairwise weakly

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Medical Report Generation Based on Segment-Enhanced Contrastive Representation Learning 12th

Medical Report Generation Based on Segment-Enhanced Contras...

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12th National CCF Conference on Natural Language Processing and Chinese Computing, NLPCC 2023

作者： Zhao, Ruoqing Wang, Xi Dai, Hongliang Gao, Pan Li, Piji College of Computer Science and Technology Nanjing University of Aeronautics and Astronautics MIIT Key Laboratory of Pattern Analysis and Machine Intelligence Nanjing China

ISBN: (纸本)9783031446955

Automated radiology report generation has the potential to improve radiology reporting and alleviate the workload of radiologists. However, the medical report generation task poses unique challenges due to the limited availability of medical data and the presence of data bias. To maximize the utility of available data and reduce data bias, we propose MSCL (Medical image Segmentation with Contrastive Learning), a framework that utilizes the Segment Anything Model (SAM) to segment organs, abnormalities, bones, etc., and can pay more attention to the meaningful ROIs in the image to get better visual representations. Then we introduce a supervised contrastive loss that assigns more weight to reports that are semantically similar to the target while training. The design of this loss function aims to mitigate the impact of data bias and encourage the model to capture the essential features of a medical image and generate high-quality reports. Experimental results demonstrate the effectiveness of our proposed model, where we achieve state-of-the-art performance on the IU X-Ray public dataset. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023.

关键词： Radiology

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Source-free open-set domain adaptation via unknown-aware global–local learning

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Knowledge-Based Systems 2025年 323卷

作者： Qing Tian Yanzhi Li Canyu Sun Xiang Liu School of Software Nanjing University of Information Science and Technology Nanjing 210044 China Wuxi Institute of Technology Nanjing University of Information Science and Technology Wuxi 214000 China MIIT Key Laboratory of Pattern Analysis and Machine Intelligence Nanjing University of Aeronautics and Astronautics Nanjing 211106 China

Source-free open-set domain adaptation (SFODA) seeks to promote target domain learning using a model pre-trained on the source domain, where there are domain and category shifts between two domains. The main challenges in SFODA is to recognize target-known instances as one of the shared classes, while rejecting target-unknown instances as unknown classes. Existing SFODA methods primarily rely on task-specific thresholds to differentiate between known and unknown classes, which is typically complex and lacks the information exploration of unknown classes during the source model generation. To address the aforementioned limitations, we propose a novel SFODA approach called unknown-aware global–local learning (UAGL). Specially, UAGL calibrates the traditional closed-set classifier to an open-set classifier by incorporating a placeholder as an indicator of unknown classes, which avoids the cumbersome adjustment of task-specific thresholds. Moreover, we introduce the class-balanced local consensus clustering technique to induce the target model to form a more compact intra-class and more dispersed inter-class feature space. The entropy-guided adversarial global separation is simultaneously designed to depict clearer classification boundaries between the known and unknown classes. Finally, we conduct a range of experiments to verify the effectiveness and superiority of UAGL in comparison to existing state-of-the-art methods.

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Graph Hyperalignment for Multi-subject fMRI Functional Alignment 1

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1st International Workshop on Graph Learning in Medical Imaging, GLMI 2019 held in conjunction with the 22nd International Conference on Medical Image Computing and Computer-Assisted Intervention, MICCAI 2019

作者： Li, Weida Chen, Fang Zhang, Daoqiang College of Computer Science and Technology MIIT Key Laboratory of Pattern Analysis and Machine Intelligence Nanjing University of Aeronautics and Astronautics Nanjing China

ISBN: (数字)9783030358174

ISBN: (纸本)9783030358167

In fMRI analysis, the scientist seeks to aggregate multi-subject fMRI data so that inferences shared across subjects can be achieved. The challenge is to eliminate the variability of anatomical structure and functional topography of the human brain, which calls for aligning fMRI data across subjects. However, the existing methods do not exploit the geometry of the stimuli, which can be inferred by using certain domain knowledge and then serve as a priori. In this paper, such geometry is encoded in a graph matrix, and we propose an algorithm named Graph Hyperalignment for leveraging it. Specifically, a kernel-based optimization is developed to allow for non-linear feature extraction. To tackle overfitting caused by the high-spatial-and-low-temporal resolution of fMRI, the data in the new feature space are assumed to lie in a low-dimensional affine subspace, which can be implicitly integrated into the proposed optimization. Unlike other iterative existing methods, GHA reaches an optimal solution directly. Examining over four real datasets, Graph Hyperaligment achieves superior results to other methods. © 2019, Springer Nature Switzerland AG.

关键词： Domain Knowledge

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Sign-aware Perturbations Regression

Sign-aware Perturbations Regression

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2021 SIAM International Conference on Data Mining, SDM 2021

作者： Li, Zhongnian Zhang, Tao Shao, Wei Chen, Songcan Zhang, Daoqiang MIIT Key Laboratory of Pattern Analysis and Machine Intelligence College of Computer Science and Technology Nanjing University of Aeronautics and Astronautics Nanjing China

ISBN: (纸本)9781611976700

This paper presents the first study on Sign-aware Perturbations Regression (SaPR), where the observed response variables contain the aware sign (negative or positive) perturbations. In order to predict the non-perturbation response variables, we propose a novel parameter estimator SZOM (i.e.,Setting Zero Operator Method), which aims at taking full advantage of the aware perturbations information to correct the mistake values in the estimation process with computationally efficiency. In this paper, the two aspects of theoretical analysis are proposed to deeply understand our method. Firstly, we establish the perturbation parameter error upper bound and prove consistency guarantee in the linear regression scenario. Secondly, we introduce the generalization error bound for the proposed SZMO, which indicates that the error bound is related to the value and the number of negative and positive perturbations. The effectiveness of the proposed approach is well validated by the experimental results on both synthetic and real datasets. © 2021 by SIAM.

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Adaptive Joint Attention with Reinforcement Training for Convolutional Image Caption 1st

Adaptive Joint Attention with Reinforcement Training for C...

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1st International Workshop on Human Brain and Artificial intelligence, HBAI 2019, held in conjunction with the 28th International Joint Conference on Artificial intelligence, IJCAI 2019

作者： Chen, Ruoyu Li, Zhongnian Zhang, Daoqiang College of Computer Science and Technology MIIT Key Laboratory of Pattern Analysis and Machine Intelligence Nanjing University of Aeronautics and Astronautics Nanjing China

ISBN: (纸本)9789811513978

A convolutional decoder for image caption has proven to be easier to train than the Long Short Term Memory (LSTM) decoder [2]. However, previous convolutional image captioning methods are not good at capture the relationship between generated words, which could lead to failure in predicting visually unrelated words. To address this issue, we propose an Adaptive Joint Attention (AJA) module for the convolutional decoder, by incorporating self-attention to explore the correlation between generated words automatically. Specifically, we develop a word gate with multi-head self-attention to directly capture words’ relationship. An adaptive combination strategy is proposed to learn which word is less related to image information. Besides, reinforcement learning is applied for directly optimizing the non-differentiable metrics while avoiding the exposure bias during inference. Extensive evaluations on two public data sets demonstrate that our method outperforms several state-of-the-art approaches in image captioning task. © 2019, Springer Nature Singapore Pte Ltd.

关键词： Computer vision

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