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Yancheng Wang

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7 papers

2 author rows

IROS Conference 2025 Conference Paper

Design of scalable orthogonal digital encoding architecture for large-area flexible tactile sensing in robotics

Weijie Liu
Ziyi Qiu
Shihang Wang
Deqing Mei
Yancheng Wang

Human-like embodied tactile perception is crucial for the next-generation intelligent robotics. Achieving large-area, full-body soft coverage with high sensitivity and rapid response, akin to human skin, remains a formidable challenge due to critical bottlenecks in encoding efficiency and wiring complexity in existing flexible tactile sensors, thus significantly hinder the scalability and real-time performance required for human skin-level tactile perception. Herein, we present a new architecture employing code division multiple access- inspired orthogonal digital encoding to overcome these challenges. Our decentralized encoding strategy transforms conventional serial signal transmission by enabling parallel superposition of energy-orthogonal base codes from distributed sensing nodes, drastically reducing wiring requirements and increasing data throughput. We implemented and validated this strategy with off-the-shelf 16-node sensing array to reconstruct the pressure distribution, achieving a temporal resolution of 12. 8 ms using only a single transmission wire. Crucially, the architecture can maintain sub-20ms latency across orders-of-magnitude variations in node number (to thousands of nodes). By fundamentally redefining signal encoding paradigms in soft electronics, this work opens new frontiers in developing scalable embodied intelligent systems with human-like sensory capabilities.

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TMLR Journal 2025 Journal Article

Diffusion on Graph: Augmentation of Graph Structure for Node Classification

Yancheng Wang
Changyu Liu
Yingzhen Yang

Graph diffusion models have recently been proposed to synthesize entire graphs, such as molecule graphs. Although existing methods have shown great performance in generating entire graphs for graph-level learning tasks, no graph diffusion models have been developed to generate synthetic graph structures, that is, synthetic nodes and associated edges within a given graph, for node-level learning tasks. Inspired by the research in the computer vision literature using synthetic data for enhanced performance, we propose Diffusion on Graph (DoG), which generates synthetic graph structures to boost the performance of GNNs. The synthetic graph structures generated by DoG are combined with the original graph to form an augmented graph for the training of node-level learning tasks, such as node classification and graph contrastive learning (GCL). To improve the efficiency of the generation process, a Bi-Level Neighbor Map Decoder (BLND) is introduced in DoG. To mitigate the adverse effect of the noise introduced by the synthetic graph structures, a low-rank regularization method is proposed for the training of graph neural networks (GNNs) on the augmented graphs. Extensive experiments on various graph datasets for semi-supervised node classification and graph contrastive learning have been conducted to demonstrate the effectiveness of DoG with low-rank regularization. The code of DoG is available at \url{https://github.com/Statistical-Deep-Learning/DoG}.

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UAI Conference 2025 Conference Paper

Informative Synthetic Data Generation for Thorax Disease Classification

Yancheng Wang
Rajeev Goel
Marko Jojic
Alvin C. Silva
Teresa Wu
Yingzhen Yang

Deep Neural Networks (DNNs), including architectures such as Vision Transformers (ViTs), have achieved remarkable success in medical imaging tasks. However, their performance typically hinges on the availability of large-scale, high-quality labeled datasets-resources that are often scarce or infeasible to obtain in medical domains. Generative Data Augmentation (GDA) offers a promising remedy by supplementing training sets with synthetic data generated via generative models like Diffusion Models (DMs). Yet, this approach introduces a critical challenge: synthetic data often contains significant noise, which can degrade the performance of classifiers trained on such augmented datasets. Prior solutions, including data selection and re-weighting techniques, often rely on access to clean metadata or pretrained external classifiers. In this work, we propose \emph{Informative Data Selection} (IDS), a principled sample re-weighting framework grounded in the Information Bottleneck (IB) principle. IDS assigns higher weights to more informative synthetic samples, thereby improving classifier performance in GDA-enhanced training for thorax disease classification. Extensive experiments demonstrate that IDS significantly outperforms existing data selection and re-weighting baselines. Our code is publicly available at \url{https: //github. com/Statistical-Deep-Learning/IDS}.

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NeurIPS Conference 2024 Conference Paper

Learning Low-Rank Feature for Thorax Disease Classification

Yancheng Wang
Rajeev Goel
Utkarsh Nath
Alvin C. Silva
Teresa Wu
Yingzhen Yang

Deep neural networks, including Convolutional Neural Networks (CNNs) and Visual Transformers (ViT), have achieved stunning success in the medical image domain. We study thorax disease classification in this paper. Effective extraction of features for the disease areas is crucial for disease classification on radiographic images. While various neural architectures and training techniques, such as self-supervised learning with contrastive/restorative learning, have been employed for disease classification on radiographic images, there are no principled methods that can effectively reduce the adverse effect of noise and background or non-disease areas on the radiographic images for disease classification. To address this challenge, we propose a novel Low-Rank Feature Learning (LRFL) method in this paper, which is universally applicable to the training of all neural networks. The LRFL method is both empirically motivated by a Low Frequency Property (LFP) and theoretically motivated by our sharp generalization bound for neural networks with low-rank features. LFP not only widely exists in deep neural networks for generic machine learning but also exists in all the thorax medical datasets studied in this paper. In the empirical study, using a neural network such as a ViT or a CNN pre-trained on unlabeled chest X-rays by Masked Autoencoders (MAE), our novel LRFL method is applied on the pre-trained neural network and demonstrates better classification results in terms of both multi-class area under the receiver operating curve (mAUC) and classification accuracy than the current state-of-the-art. The code of LRFL is available at \url{https: //github. com/Statistical-Deep-Learning/LRFL}.

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UAI Conference 2024 Conference Paper

Neural Architecture Search Finds Robust Models by Knowledge Distillation

Utkarsh Nath
Yancheng Wang
Yingzhen Yang

Despite their superior performance, Deep Neural Networks (DNNs) are often vulnerable to adversarial attacks. Neural Architecture Search (NAS), a method for automatically designing the architectures of DNNs, has shown remarkable performance across various machine learning applications. However, the adversarial robustness of architectures learned by NAS against adversarial threats remains under-explored. By integrating a robust teacher, we examine whether NAS can yield a robust neural architecture by inheriting robustness from the teacher. In this paper, we propose Robust Neural Architecture Search by Cross-Layer Knowledge Distillation (RNAS-CL), a novel NAS algorithm that enhances the robustness of architectures learned by NAS through employing cross-layer knowledge distillation from a robust teacher. Distinct from previous knowledge distillation approaches that only align student-teacher outputs at the final layer, RNAS-CL dynamically searches for the optimal teacher layer to guide each student layer. Our experimental findings validate the effectiveness of RNAS-CL, demonstrating that it can generate both compact and adversarially robust neural architectures. Our results pave the way for developing new strategies for compact and robust neural architecture design applicable across various fields. The code of RNAS-CL is available at \url{https: //github. com/Statistical-Deep-Learning/RNAS-CL}.

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ICML Conference 2024 Conference Paper

Visual Transformer with Differentiable Channel Selection: An Information Bottleneck Inspired Approach

Yancheng Wang
Ping Li 0001
Yingzhen Yang

Self-attention and transformers have been widely used in deep learning. Recent efforts have been devoted to incorporating transformer blocks into different types of neural architectures, including those with convolutions, leading to various visual transformers for computer vision tasks. In this paper, we propose a novel and compact transformer block, Transformer with Differentiable Channel Selection, or DCS-Transformer. DCS-Transformer features channel selection in the computation of the attention weights and the input/output features of the MLP in the transformer block. Our DCS-Transformer is compatible with many popular and compact transformer networks, such as MobileViT and EfficientViT, and it reduces the FLOPs of the visual transformers while maintaining or even improving the prediction accuracy. In the experiments, we replace all the transformer blocks in MobileViT and EfficientViT with DCS-Transformer blocks, leading to DCS-Transformer networks with different backbones. The DCS-Transformer is motivated by reduction of Information Bottleneck, and a novel variational upper bound for the IB loss which can be optimized by SGD is derived and incorporated into the training loss of the network with DCS-Transformer. Extensive results on image classification and object detection evidence that DCS-Transformer renders compact and efficient visual transformers with comparable or much better prediction accuracy than the original visual transformers. The code of DCS-Transformer is available at https: //github. com/Statistical-Deep-Learning/DCS-Transformer.

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AAAI Conference 2023 Conference Paper

Eliciting Structural and Semantic Global Knowledge in Unsupervised Graph Contrastive Learning

Kaize Ding
Yancheng Wang
Yingzhen Yang
Huan Liu

Graph Contrastive Learning (GCL) has recently drawn much research interest for learning generalizable node representations in a self-supervised manner. In general, the contrastive learning process in GCL is performed on top of the representations learned by a graph neural network (GNN) backbone, which transforms and propagates the node contextual information based on its local neighborhoods. However, nodes sharing similar characteristics may not always be geographically close, which poses a great challenge for unsupervised GCL efforts due to their inherent limitations in capturing such global graph knowledge. In this work, we address their inherent limitations by proposing a simple yet effective framework -- Simple Neural Networks with Structural and Semantic Contrastive Learning} (S^3-CL). Notably, by virtue of the proposed structural and semantic contrastive learning algorithms, even a simple neural network can learn expressive node representations that preserve valuable global structural and semantic patterns. Our experiments demonstrate that the node representations learned by S^3-CL) achieve superior performance on different downstream tasks compared with the state-of-the-art unsupervised GCL methods. Implementation and more experimental details are publicly available at https://github.com/kaize0409/S-3-CL.

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