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Xingyu Chen

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33 papers
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33

AAAI Conference 2026 Conference Paper

SegDINO3D: 3D Instance Segmentation Empowered by Both Image-Level and Object-Level 2D Features

  • Jinyuan Qu
  • Hongyang Li
  • Xingyu Chen
  • Shilong Liu
  • Yukai Shi
  • Tianhe Ren
  • Ruitao Jing
  • Lei Zhang

In this paper, we present SegDINO3D, a novel Transformer encoder-decoder framework for 3D instance segmentation. As 3D training data is generally not as sufficient as 2D training images, SegDINO3D is designed to fully leverage 2D representation from a pre-trained 2D detection model, including both image-level and object-level features, for improving 3D representation. SegDINO3D takes both a point cloud and its associated 2D images as input. In the encoder stage, it first enriches each 3D point by retrieving 2D image features from its corresponding image views and then leverages a 3D encoder for 3D context fusion. In the decoder stage, it formulates 3D object queries as 3D anchor boxes and performs cross-attention from 3D queries to 2D object queries obtained from 2D images using the 2D detection model. These 2D object queries serve as a compact object-level representation of 2D images, effectively avoiding the challenge of keeping thousands of image feature maps in the memory while faithfully preserving the knowledge of the pre-trained 2D model. The introducing of 3D box queries also enables the model to modulate cross-attention using the predicted boxes for more precise querying. SegDINO3D achieves the state-of-the-art performance on the ScanNetV2 and ScanNet200 3D instance segmentation benchmarks. Notably, on the challenging ScanNet200 dataset, SegDINO3D significantly outperforms prior methods by +8.7 and +6.8 mAP on the validation and hidden test sets, respectively, demonstrating its superiority.

IROS Conference 2025 Conference Paper

AdaToken-3D: Dynamic Spatial Gating for Efficient 3D Large Multimodal-Models Reasoning

  • Kai Zhang
  • Xingyu Chen
  • Xiaofeng Zhang

Large Multimodal Models (LMMs) have become a pivotal research focus in deep learning, demonstrating remarkable capabilities in 3D scene understanding. However, current 3D LMMs employing thousands of spatial tokens for multimodal reasoning suffer from critical inefficiencies: excessive computational overhead and redundant information flows. Unlike 2D VLMs processing single images, 3D LMMs exhibit inherent architectural redundancy due to the heterogeneous mechanisms between spatial tokens and visual tokens. To address this challenge, we propose AdaToken-3D, an adaptive spatial token optimization framework that dynamically prunes redundant tokens through spatial contribution analysis. Our method automatically tailors pruning strategies to different 3D LMM architectures by quantifying token-level information flows via attention pattern mining. Extensive experiments on LLaVA-3D (a 7B parameter 3D-LMM) demonstrate that AdaToken-3D achieves 21% faster inference speed and 63% FLOPs reduction while maintaining original task accuracy. Beyond efficiency gains, this work systematically investigates redundancy patterns in multimodal spatial information flows through quantitative token interaction analysis. Our findings reveal that over 60% of spatial tokens contribute minimally (<5%) to the final predictions, establishing theoretical foundations for efficient 3D multimodal learning.

NeurIPS Conference 2025 Conference Paper

Ctrl-DNA: Controllable Cell-Type-Specific Regulatory DNA Design via Constrained RL

  • Xingyu Chen
  • Shihao Ma
  • Runsheng Lin
  • Jiecong Lin
  • Bo Wang

Designing regulatory DNA sequences that achieve precise cell-type-specific gene expression is crucial for advancements in synthetic biology, gene therapy and precision medicine. Although transformer-based language models (LMs) can effectively capture patterns in regulatory DNA, their generative approaches often struggle to produce novel sequences with reliable cell-specific activity. Here, we introduce Ctrl-DNA, a novel constrained reinforcement learning (RL) framework tailored for designing regulatory DNA sequences with controllable cell-type specificity. By formulating regulatory sequence design as a biologically informed constrained optimization problem, we apply RL to autoregressive genomic LMs, enabling the models to iteratively refine sequences that maximize regulatory activity in targeted cell types while constraining off-target effects. Our evaluation on human promoters and enhancers demonstrates that Ctrl-DNA consistently outperforms existing generative and RL-based approaches, generating high-fitness regulatory sequences and achieving state-of-the-art cell-type specificity. Moreover, Ctrl-DNA-generated sequences capture key cell-type-specific transcription factor binding sites (TFBS), short DNA motifs recognized by regulatory proteins that control gene expression, demonstrating the biological plausibility of the generated sequences.

ICML Conference 2025 Conference Paper

Do NOT Think That Much for 2+3=? On the Overthinking of Long Reasoning Models

  • Xingyu Chen
  • Jiahao Xu
  • Tian Liang
  • Zhiwei He 0002
  • Jianhui Pang
  • Dian Yu 0001
  • Linfeng Song
  • Qiuzhi Liu

The remarkable performance of long reasoning models can be attributed to their ability to emulate human-like long-time thinking during inference. These models employ extended chain-of-thought (CoT) processes, exploring multiple strategies to enhance problem-solving capabilities. However, a critical question remains: How to intelligently and efficiently scale computational resources during testing. This paper presents the first comprehensive study on the prevalent issue of overthinking in these models, where long reasoning models generate redundant solutions that contribute minimally to accuracy and diversity, thereby wasting computational resources on simple problems with minimal benefit. We introduce novel efficiency metrics from both outcome and process perspectives to evaluate the rational use of computational resources by long reasoning models. Using a self-training paradigm, we propose strategies to mitigate overthinking, simplifying reasoning processes without compromising accuracy. Experimental results show that our approach successfully reduces computational overhead while preserving model performance across a range of testsets with varying difficulty levels, such as GSM8K, MATH500, GPQA, and AIME. Our code is open-source and available at https: //github. com/galaxyChen/overthinking.

AAMAS Conference 2025 Conference Paper

Offline Multi-Agent Preference-based Reinforcement Learning with Agent-aware Direct Preference Optimization

  • Qian Kou
  • Mingyang Li
  • Zeyang Liu
  • Long Qian
  • Zhuoran Chen
  • Lipeng Wan
  • Xingyu Chen
  • Xuguang Lan

Multi-agent Preference-Based Reinforcement Learning (MAPbRL) is promising in offline policy learning by leveraging human preferences to replace complex manual reward designing. Current MAPbRL methods use complicated structures to realize better reward modeling with off-the-shelf MARL algorithms and obtain the joint policy based on it. However, it faces a severe preference-behavior mismatch problem stemming from the instability of RL training and global-local preference inconsistency datasets in offline MARL, resulting in potential suboptimal policy convergence. To address this problem, we propose Agent-aware Multi-Agent Direct Preference Optimization (AMADPO) by utilizing a multi-agent preference predictor to guide agent-aware direct optimization from imbalanced preference labels, which can learn coordination policy from both positive and negative segments. Experimental results in SMAC environment show substantial improvements in global-local preference inconsistency datasets, demonstrating the effectiveness of AMADPO in solving the preference-behavior mismatch problem.

IROS Conference 2025 Conference Paper

OmniPose6D: Towards Short-Term Object Pose Tracking in Dynamic Scenes from Monocular RGB

  • Yunzhi Lin
  • Yipu Zhao
  • Fu-Jen Chu
  • Xingyu Chen
  • Weiyao Wang 0001
  • Hao Tang
  • Patricio A. Vela
  • Matt Feiszli

To address the challenge of short-term object pose tracking in dynamic environments with monocular RGB input, we introduce a large-scale synthetic dataset Omni-Pose6D, crafted to mirror the diversity of real-world conditions. We additionally present a benchmarking framework for a comprehensive comparison of pose tracking algorithms. We propose a pipeline featuring an uncertainty-aware keypoint refinement network, employing probabilistic modeling to refine pose estimation. Comparative evaluations demonstrate that our approach achieves performance superior to existing baselines on real datasets, underscoring the effectiveness of our synthetic dataset and refinement technique in enhancing tracking precision in dynamic contexts. Our contributions set a new precedent for the development and assessment of object pose tracking methodologies in complex scenes.

ICLR Conference 2025 Conference Paper

RaSA: Rank-Sharing Low-Rank Adaptation

  • Zhiwei He 0002
  • Zhaopeng Tu
  • Xing Wang 0007
  • Xingyu Chen
  • Zhijie Wang
  • Jiahao Xu
  • Tian Liang
  • Wenxiang Jiao

Low-rank adaptation (LoRA) has been prominently employed for parameter-efficient fine-tuning of large language models (LLMs). However, the limited expressive capacity of LoRA, stemming from the low-rank constraint, has been recognized as a bottleneck, particularly in rigorous tasks like code generation and mathematical reasoning. To address this limitation, we introduce Rank-Sharing Low-Rank Adaptation (RaSA), an innovative extension that enhances the expressive capacity of LoRA by leveraging partial rank sharing across layers. By forming a shared rank pool and applying layer-specific weighting, RaSA effectively increases the number of ranks without augmenting parameter overhead. Our theoretically grounded and empirically validated approach demonstrates that RaSA not only maintains the core advantages of LoRA but also significantly boosts performance in challenging code and math tasks. Code, data and scripts are available at: https://github.com/zwhe99/RaSA.

IJCAI Conference 2025 Conference Paper

State Revisit and Re-explore: Bridging Sim-to-Real Gaps in Offline-and-Online Reinforcement Learning with An Imperfect Simulator

  • Xingyu Chen
  • Jiayi Xie
  • Zhijian Xu
  • Ruixun Liu
  • Shuai Yang
  • Zeyang Liu
  • Lipeng Wan
  • Xuguang Lan

In reinforcement learning (RL) based robot skill acquisition, a high-fidelity simulator is usually indispensable but unattainable since the real environment dynamics are difficult to model, which leads to severe sim-to-real gaps. Existing methods solve this problem by combining offline and online RL to jointly learn transferable policies from limited offline data and imperfect simulators. However, due to the unrestricted exploration in the imperfect simulator, the hybrid offline-and-online RL methods inevitably suffer from low sample efficiency and insufficient state-action space coverage during training. To solve this problem, we propose a State Revisit and Re-exploration (SR2) hybrid offline-and-online RL framework. In particular, the proposed algorithm employs a meta-policy and a sub-policy, where the meta-policy aims to find high-quality states in the offline trajectories for online exploration, and the sub-policy learns the robot skill using mixed offline and online data. By introducing the state revisit and explore mechanism, our approach efficiently improves performance on a set of sim-to-real robotic tasks. Through extensive simulation and real-world tasks, we demonstrate the superior performance of our approach against other state-of-the-art methods.

NeurIPS Conference 2025 Conference Paper

Stochastic Momentum Methods for Non-smooth Non-Convex Finite-Sum Coupled Compositional Optimization

  • Xingyu Chen
  • Bokun Wang
  • Ming Yang
  • Qihang Lin
  • Tianbao Yang

Finite-sum Coupled Compositional Optimization (FCCO), characterized by its coupled compositional objective structure, emerges as an important optimization paradigm for addressing a wide range of machine learning problems. In this paper, we focus on a challenging class of non-convex non-smooth FCCO, where the outer functions are non-smooth weakly convex or convex and the inner functions are smooth or weakly convex. Existing state-of-the-art result face two key limitations: (1) a high iteration complexity of $O(1/\epsilon^6)$ under the assumption that the stochastic inner functions are Lipschitz continuous in expectation; (2) reliance on vanilla SGD-type updates, which are not suitable for deep learning applications. Our main contributions are two fold: (i) We propose stochastic momentum methods tailored for non-smooth FCCO that come with provable convergence guarantees; (ii) We establish a **new state-of-the-art** iteration complexity of $O(1/\epsilon^5)$. Moreover, we apply our algorithms to multiple inequality constrained non-convex optimization problems involving smooth or weakly convex functional inequality constraints. By optimizing a smoothed hinge penalty based formulation, we achieve a **new state-of-the-art** complexity of $O(1/\epsilon^5)$ for finding an (nearly) $\epsilon$-level KKT solution. Experiments on three tasks demonstrate the effectiveness of the proposed algorithms.

NeurIPS Conference 2025 Conference Paper

The First Few Tokens Are All You Need: An Efficient and Effective Unsupervised Prefix Fine-Tuning Method for Reasoning Models

  • Ke Ji
  • Jiahao Xu
  • Tian Liang
  • Qiuzhi Liu
  • Zhiwei He
  • Xiaoyuan Liu
  • Xingyu Chen
  • Junying Chen

Improving the reasoning capabilities of large language models (LLMs) typically requires supervised fine-tuning with labeled data or computationally expensive sampling. We introduce Unsupervised Prefix Fine-Tuning (UPFT), which leverages the observation of Prefix Self-Consistency -- the shared initial reasoning steps across diverse solution trajectories -- to enhance LLM reasoning efficiency. By training exclusively on the initial prefix substrings (as few as 8 tokens), UPFT removes the need for labeled data or exhaustive sampling. Experiments on reasoning benchmarks show that UPFT matches the performance of supervised methods such as Rejection Sampling Fine-Tuning, while reducing training time by 75\% and sampling cost by 99\%. Further analysis reveals that errors tend to appear in later stages of the reasoning process and that prefix-based training preserves the model’s structural knowledge. This work demonstrates how minimal unsupervised fine-tuning can unlock substantial reasoning gains in LLMs, offering a scalable and resource-efficient alternative to conventional approaches.

NeurIPS Conference 2025 Conference Paper

Thoughts Are All Over the Place: On the Underthinking of Long Reasoning Models

  • Yue Wang
  • Qiuzhi Liu
  • Jiahao Xu
  • Tian Liang
  • Xingyu Chen
  • Zhiwei He
  • Linfeng Song
  • Dian Yu

Long reasoning models (LRMs) such as OpenAI's o1 and DeepSeek's R1 have demonstrated remarkable abilities in complex reasoning tasks by scaling test-time compute and exhibiting human-like deep thinking. However, we identify a phenomenon we term underthinking, where LRMs frequently switch between different reasoning thoughts without sufficiently exploring promising paths to reach a correct solution. This behavior leads to inadequate depth of reasoning and decreased performance, particularly on challenging mathematical problems. To systematically analyze this issue, we conduct experiments on three challenging test sets and two representative open-source LRMs, revealing that frequent thought switching correlates with incorrect responses. We introduce a novel metric to quantify underthinking by measuring token efficiency in incorrect answers. To address underthinking, we propose a decoding strategy with thought switching penalty (Tip) that discourages premature transitions between thoughts, encouraging deeper exploration of each reasoning path. Experimental results demonstrate that our approach improves accuracy across challenging datasets without requiring model fine-tuning. Our findings contribute to understanding reasoning inefficiencies in LRMs and offer a practical solution to enhance their problem-solving capabilities. Our code is open-source and available at https: //github. com/wangyuenlp/underthinking.

NeurIPS Conference 2025 Conference Paper

Two Experts Are All You Need for Steering Thinking: Reinforcing Cognitive Effort in MoE Reasoning Models Without Additional Training

  • Mengru Wang
  • Xingyu Chen
  • Yue Wang
  • Zhiwei He
  • Jiahao Xu
  • Tian Liang
  • Qiuzhi Liu
  • Yunzhi Yao

Mixture-of-Experts (MoE) architectures within Large Reasoning Models (LRMs) have achieved impressive reasoning capabilities by selectively activating experts to facilitate structured cognitive processes. Despite notable advances, existing reasoning models often suffer from cognitive inefficiencies like overthinking and underthinking. To address these limitations, we introduce a novel inference-time steering methodology called Reinforcing Cognitive Experts (RICE), designed to improve reasoning depth and efficiency without additional training or complex heuristics. Leveraging normalized Pointwise Mutual Information (nPMI), we systematically identify specialized experts, termed cognitive experts that orchestrate meta-level reasoning operations characterized by tokens like. Empirical evaluations with leading MoE-based LRMs (DeepSeek-R1 and Qwen3-235B) on rigorous quantitative and scientific reasoning benchmarks (AIME and GPQA Diamond) demonstrate noticeable and consistent improvements in reasoning accuracy, cognitive efficiency, and cross-domain generalization. Crucially, our lightweight approach substantially outperforms prevalent reasoning-steering techniques, such as prompt design and decoding constraints, while preserving the model's general instruction-following skills. These results highlight reinforcing cognitive experts as a promising, practical, and interpretable direction to enhance cognitive efficiency within advanced reasoning models.

IROS Conference 2024 Conference Paper

A Laser-Induced Graphene-Based Flexible Multimodal Sensor for Material and Texture Perception

  • Youning Duo
  • Jinxi Duan
  • Xingyu Chen
  • Wenbo Liu
  • Shengxue Wang
  • Li Wen

Humans can perceive and interact with their surroundings through multiple senses. For intelligent robots, multimodal sensors are crucial for them to perceive and understand the environment. In this work, we propose a multi-layered flexible multimodal sensor based on laser-induced graphene, capable of detecting both touchless signals (such as the distance from external objects and their material) and tactile signals (three-dimensional force). The sensor has advantages in durability and stability. Under normal force, the sensitivity is –7. 449% N –1 in the range of 0 N to 1. 5 N and –0. 273% N –1 in the range of 1. 5 N to 30 N, with fast response (17 ms) and recovery (37 ms). Furthermore, using the Convolutional Neural Networks (CNN) model, we develop an intelligent soft robot system capable of distinguishing objects of different materials and fabric textures with accuracies of 99% and 88. 75%, respectively. The proposed flexible multimodal sensor holds a significant effect on the perception and interaction of intelligent robots with the environment.

ICML Conference 2024 Conference Paper

Cell2Sentence: Teaching Large Language Models the Language of Biology

  • Daniel LeVine
  • Syed Asad Rizvi
  • Sacha Lévy
  • Nazreen Pallikkavaliyaveetil
  • David Zhang
  • Xingyu Chen
  • Sina Ghadermarzi
  • Ruiming Wu

We introduce Cell2Sentence (C2S), a novel method to directly adapt large language models to a biological context, specifically single-cell transcriptomics. By transforming gene expression data into "cell sentences, " C2S bridges the gap between natural language processing and biology. We demonstrate cell sentences enable the fine-tuning of language models for diverse tasks in biology, including cell generation, complex cell-type annotation, and direct data-driven text generation. Our experiments reveal that GPT-2, when fine-tuned with C2S, can generate biologically valid cells based on cell type inputs, and accurately predict cell types from cell sentences. This illustrates that language models, through C2S fine-tuning, can acquire a significant understanding of single-cell biology while maintaining robust text generation capabilities. C2S offers a flexible, accessible framework to integrate natural language processing with transcriptomics, utilizing existing models and libraries for a wide range of biological applications.

ICRA Conference 2024 Conference Paper

Experience Consistency Distillation Continual Reinforcement Learning for Robotic Manipulation Tasks

  • Chao Zhao
  • Jie Xu
  • Ru Peng
  • Xingyu Chen
  • Kuizhi Mei
  • Xuguang Lan

Continual reinforcement learning, which aims to help robots acquire skills without catastrophic forgetting, obviating the need to re-learn all tasks from scratch. In order to enable lifelong acquisition of skills in robots, replay-based continual reinforcement learning has emerged as a promising research direction. These techniques replay data from previous tasks to mitigate forgetting when learning new skills. However, existing replay-based methods store poor representative experience, and the experience utilization of old tasks is inefficient. To address these issues, we propose an experience consistency distillation method for robot continual reinforcement learning to improve the data efficiency of the experience. Specifically, the experience of old tasks are distilled to obtain Markov Decision Process (MDP) data with high compression ratio and information content. To ensure consistent data distributions before and after distillation, we further utilize a Fréchet Inception Distance (FID) loss as a regularization constraint. In order to improve experience utilization efficiency, the policy is then trained using both the distilled data and current task data, with policy distillation performed based on uncertainty metrics. Our method is validated in the continual reinforcement learning simulation platform and real scene with a UR5e robot arm. Experimental results indicate that our method achieves higher success and lower buffer size requirement compared to other methods.

NeurIPS Conference 2024 Conference Paper

Grounded Answers for Multi-agent Decision-making Problem through Generative World Model

  • Zeyang Liu
  • Xinrui Yang
  • Shiguang Sun
  • Long Qian
  • Lipeng Wan
  • Xingyu Chen
  • Xuguang Lan

Recent progress in generative models has stimulated significant innovations in many fields, such as image generation and chatbots. Despite their success, these models often produce sketchy and misleading solutions for complex multi-agent decision-making problems because they miss the trial-and-error experience and reasoning as humans. To address this limitation, we explore a paradigm that integrates a language-guided simulator into the multi-agent reinforcement learning pipeline to enhance the generated answer. The simulator is a world model that separately learns dynamics and reward, where the dynamics model comprises an image tokenizer as well as a causal transformer to generate interaction transitions autoregressively, and the reward model is a bidirectional transformer learned by maximizing the likelihood of trajectories in the expert demonstrations under language guidance. Given an image of the current state and the task description, we use the world model to train the joint policy and produce the image sequence as the answer by running the converged policy on the dynamics model. The empirical results demonstrate that this framework can improve the answers for multi-agent decision-making problems by showing superior performance on the training and unseen tasks of the StarCraft Multi-Agent Challenge benchmark. In particular, it can generate consistent interaction sequences and explainable reward functions at interaction states, opening the path for training generative models of the future.

AAAI Conference 2024 Conference Paper

Imagine, Initialize, and Explore: An Effective Exploration Method in Multi-Agent Reinforcement Learning

  • Zeyang Liu
  • Lipeng Wan
  • Xinrui Yang
  • Zhuoran Chen
  • Xingyu Chen
  • Xuguang Lan

Effective exploration is crucial to discovering optimal strategies for multi-agent reinforcement learning (MARL) in complex coordination tasks. Existing methods mainly utilize intrinsic rewards to enable committed exploration or use role-based learning for decomposing joint action spaces instead of directly conducting a collective search in the entire action-observation space. However, they often face challenges obtaining specific joint action sequences to reach successful states in long-horizon tasks. To address this limitation, we propose Imagine, Initialize, and Explore (IIE), a novel method that offers a promising solution for efficient multi-agent exploration in complex scenarios. IIE employs a transformer model to imagine how the agents reach a critical state that can influence each other's transition functions. Then, we initialize the environment at this state using a simulator before the exploration phase. We formulate the imagination as a sequence modeling problem, where the states, observations, prompts, actions, and rewards are predicted autoregressively. The prompt consists of timestep-to-go, return-to-go, influence value, and one-shot demonstration, specifying the desired state and trajectory as well as guiding the action generation. By initializing agents at the critical states, IIE significantly increases the likelihood of discovering potentially important under-explored regions. Despite its simplicity, empirical results demonstrate that our method outperforms multi-agent exploration baselines on the StarCraft Multi-Agent Challenge (SMAC) and SMACv2 environments. Particularly, IIE shows improved performance in the sparse-reward SMAC tasks and produces more effective curricula over the initialized states than other generative methods, such as CVAE-GAN and diffusion models.

ICRA Conference 2024 Conference Paper

Vision-based Tip Force Estimation on a Soft Continuum Robot

  • Xingyu Chen
  • Jialei Shi
  • Helge A. Wurdemann
  • Thomas George Thuruthel

Soft continuum robots, fabricated from elastomeric materials, offer unparalleled flexibility and adaptability, making them ideal for applications such as minimally invasive surgery and inspections in constrained environments. With the miniaturization of imaging technologies and the development of novel control algorithms, these devices provide exceptional opportunities to visualize the internal structures of the human body. However, there are still challenges in accurately estimating external forces applied to these systems using current technologies. Adding additional sensors is challenging without compromising the softness of the device. This work presents a visual deformation-based force sensing framework for soft continuum robots. The core idea behind this work is that point loads lead to unique deformation profiles in an actuated soft-bodied robot. We introduce a Convolutional Neural Network-based tip force estimation method that utilizes arbitrarily placed camera images and actuation inputs to predict applied tip forces. Experimental validation was performed using the STIFF-FLOP robot, a pneumatically actuated soft robot developed for minimally invasive surgery. Our vision-based force estimation model demonstrated a sensing precision of 0. 05 N in the XY plane during testing, with data collection and training taking only 70 minutes.

NeurIPS Conference 2023 Conference Paper

CAPro: Webly Supervised Learning with Cross-modality Aligned Prototypes

  • Yulei Qin
  • Xingyu Chen
  • Yunhang Shen
  • Chaoyou Fu
  • Yun Gu
  • Ke Li
  • Xing Sun
  • Rongrong Ji

Webly supervised learning has attracted increasing attention for its effectiveness in exploring publicly accessible data at scale without manual annotation. However, most existing methods of learning with web datasets are faced with challenges from label noise, and they have limited assumptions on clean samples under various noise. For instance, web images retrieved with queries of ”tiger cat“ (a cat species) and ”drumstick“ (a musical instrument) are almost dominated by images of tigers and chickens, which exacerbates the challenge of fine-grained visual concept learning. In this case, exploiting both web images and their associated texts is a requisite solution to combat real-world noise. In this paper, we propose Cross-modality Aligned Prototypes (CAPro), a unified prototypical contrastive learning framework to learn visual representations with correct semantics. For one thing, we leverage textual prototypes, which stem from the distinct concept definition of classes, to select clean images by text matching and thus disambiguate the formation of visual prototypes. For another, to handle missing and mismatched noisy texts, we resort to the visual feature space to complete and enhance individual texts and thereafter improve text matching. Such semantically aligned visual prototypes are further polished up with high-quality samples, and engaged in both cluster regularization and noise removal. Besides, we propose collective bootstrapping to encourage smoother and wiser label reference from appearance-similar instances in a manner of dictionary look-up. Extensive experiments on WebVision1k and NUS-WIDE (Web) demonstrate that CAPro well handles realistic noise under both single-label and multi-label scenarios. CAPro achieves new state-of-the-art performance and exhibits robustness to open-set recognition. Codes are available at https: //github. com/yuleiqin/capro.

AAAI Conference 2023 Conference Paper

FoPro: Few-Shot Guided Robust Webly-Supervised Prototypical Learning

  • Yulei Qin
  • Xingyu Chen
  • Chao Chen
  • Yunhang Shen
  • Bo Ren
  • Yun Gu
  • Jie Yang
  • Chunhua Shen

Recently, webly supervised learning (WSL) has been studied to leverage numerous and accessible data from the Internet. Most existing methods focus on learning noise-robust models from web images while neglecting the performance drop caused by the differences between web domain and real-world domain. However, only by tackling the performance gap above can we fully exploit the practical value of web datasets. To this end, we propose a Few-shot guided Prototypical (FoPro) representation learning method, which only needs a few labeled examples from reality and can significantly improve the performance in the real-world domain. Specifically, we initialize each class center with few-shot real-world data as the ``realistic" prototype. Then, the intra-class distance between web instances and ``realistic" prototypes is narrowed by contrastive learning. Finally, we measure image-prototype distance with a learnable metric. Prototypes are polished by adjacent high-quality web images and involved in removing distant out-of-distribution samples. In experiments, FoPro is trained on web datasets with a few real-world examples guided and evaluated on real-world datasets. Our method achieves the state-of-the-art performance on three fine-grained datasets and two large-scale datasets. Compared with existing WSL methods under the same few-shot settings, FoPro still excels in real-world generalization. Code is available at https://github.com/yuleiqin/fopro.

IROS Conference 2023 Conference Paper

LIO-PPF: Fast LiDAR-Inertial Odometry via Incremental Plane Pre-Fitting and Skeleton Tracking

  • Xingyu Chen
  • Peixi Wu
  • Ge Li 0002
  • Thomas H. Li

As a crucial infrastructure of intelligent mobile robots, LiDAR-Inertial odometry (LIO) provides the basic capability of state estimation by tracking LiDAR scans. The high-accuracy tracking generally involves the $k\text{NN}$ search, which is used with minimizing the point-to-plane distance. The cost for this, however, is maintaining a large local map and performing $k\text{NN}$ plane fit for each point. In this work, we reduce both time and space complexity of LIO by saving these unnecessary costs. Technically, we design a plane pre-fitting (PPF) pipeline to track the basic skeleton of the 3D scene. In PPF, planes are not fitted individually for each scan, let alone for each point, but are updated incrementally as the scene ‘flows’. Unlike $k\text{NN}$, the PPF is more robust to noisy and non-strict planes with our iterative Principal Component Analyse (iPCA) refinement. Moreover, a simple yet effective sandwich layer is introduced to eliminate false point-to-plane matches. Our method was extensively tested on a total number of 22 sequences across 5 open datasets, and evaluated in 3 existing state-of-the-art LIO systems. By contrast, LIO-PPF can consume only 36% of the original local map size to achieve up to 4x faster residual computing and 1. 92x overall FPS, while maintaining the same level of accuracy. We fully open source our implementation at https://github.com/xingyuuchen/LIO-PPF.

ICRA Conference 2023 Conference Paper

MMRDN: Consistent Representation for Multi-View Manipulation Relationship Detection in Object-Stacked Scenes

  • Han Wang
  • Jiayuan Zhang
  • Lipeng Wan 0003
  • Xingyu Chen
  • Xuguang Lan
  • Nanning Zheng 0001

Manipulation relationship detection (MRD) aims to guide the robot to grasp objects in the right order, which is important to ensure the safety and reliability of grasping in object stacked scenes. Previous works infer manipulation relationship by deep neural network trained with data collected from a predefined view, which has limitation in visual dislocation in unstructured environments. Multi-view data provide more comprehensive information in space, while a challenge of multi-view MRD is domain shift. In this paper, we propose a novel multi-view fusion framework, namely multi-view MRD network (MMRDN), which is trained by 2D and 3D multi-view data. We project the 2D data from different views into a common hidden space and fit the embeddings with a set of Von-Mises-Fisher distributions to learn the consistent representations. Besides, taking advantage of position information within the 3D data, we select a set of $K$ Maximum Vertical Neighbors (KMVN) points from the point cloud of each object pair, which encodes the relative position of these two objects. Finally, the features of multi-view 2D and 3D data are concatenated to predict the pairwise relationship of objects. Experimental results on the challenging REGRAD dataset show that MMRDN outperforms the state-of-the-art methods in multi-view MRD tasks. The results also demonstrate that our model trained by synthetic data is capable to transfer to real-world scenarios.

NeurIPS Conference 2023 Conference Paper

Object Reprojection Error (ORE): Camera pose benchmarks from lightweight tracking annotations

  • Xingyu Chen
  • Weiyao Wang
  • Hao Tang
  • Matt Feiszli

3D spatial understanding is highly valuable in the context of semantic modeling of environments, agents, and their relationships. Semantic modeling approaches employed on monocular video often ingest outputs from off-the-shelf SLAM/SfM pipelines, which are anecdotally observed to perform poorly or fail completely on some fraction of the videos of interest. These target videos may vary widely in complexity of scenes, activities, camera trajectory, etc. Unfortunately, such semantically-rich video data often comes with no ground-truth 3D information, and in practice it is prohibitively costly or impossible to obtain ground truth reconstructions or camera pose post-hoc. This paper proposes a novel evaluation protocol, Object Reprojection Error (ORE) to benchmark camera trajectories; ORE computes reprojection error for static objects within the video and requires only lightweight object tracklet annotations. These annotations are easy to gather on new or existing video, enabling ORE to be calculated on essentially arbitrary datasets. We show that ORE maintains high rank correlation with standard metrics based on groundtruth. Leveraging ORE, we source videos and annotations from Ego4D-EgoTracks, resulting in EgoStatic, a large-scale diverse dataset for evaluating camera trajectories in-the-wild.

ICRA Conference 2023 Conference Paper

Place Recognition under Occlusion and Changing Appearance via Disentangled Representations

  • Yue Chen
  • Xingyu Chen
  • Yicen Li

Place recognition is a critical and challenging task for mobile robots, aiming to retrieve an image captured at the same place as a query image from a database. Existing methods tend to fail while robots move autonomously under occlusion (e. g. , car, bus, truck) and changing appearance (e. g. , illumination changes, seasonal variation). Because they encode the image into only one code, entangling place features with appearance and occlusion features. To overcome this limitation, we propose PROCA, an unsupervised approach to decompose the image representation into three codes: a place code used as a descriptor to retrieve images, an appearance code that captures appearance properties, and an occlusion code that encodes occlusion content. Extensive experiments show that our model outperforms the state-of-the-art methods. Our code and data are available at https://github.com/rover-xingyu/PROCA.

IROS Conference 2023 Conference Paper

Prioritized Planning for Target-Oriented Manipulation via Hierarchical Stacking Relationship Prediction

  • Zewen Wu
  • Jian Tang
  • Xingyu Chen
  • Chengzhong Ma
  • Xuguang Lan
  • Nanning Zheng 0001

In scenarios involving grasping multiple targets, the learning of stacking relationships between objects is fundamental for robots to execute safely and efficiently. However, current methods lack subdivision for the hierarchy of stacking relationship types. In scenes where objects are mostly stacked in an orderly manner, they are incapable of performing human-like and high-efficient grasping decisions. This paper proposes a perception-planning method to distinguish different stacking forms between objects and generate prioritized manipulation sequences based on given target designations. We utilize a Hierarchical Stacking Relationship Network (HSRN) to discriminate the hierarchy of stacking and generate a refined Stacking Relationship Tree (SRT) for relationship description. Considering objects with high stacking stability can be processed together if necessary, we introduce an elaborate decision-making planner based on Partially Observable Markov Decision Process (POMDP), which leverages observations and generates the least grasp-consuming decision chain with robustness and is suitable for simultaneously specifying multiple targets. To verify our work, we set the scene to the dining table and augment REGRAD dataset for network training. Experiments show that our method effectively generates grasping decisions that conform to human requirements, and improves the implementation efficiency compared with existing methods on the basis of guaranteeing success rate.

ICRA Conference 2022 Conference Paper

A Continuous Learning Approach for Probabilistic Human Motion Prediction

  • Jie Xu
  • Shihong Wang
  • Xingyu Chen
  • Jiahao Zhang
  • Xuguang Lan
  • Nanning Zheng 0001

Human Motion Prediction (HMP) plays a crucial role in safe Human-Robot-Interaction (HRI). Currently, the majority of HMP algorithms are trained by massive pre-collected data. As the training data only contains a few pre-defined motion patterns, these methods cannot handle the unfamiliar motion patterns. Moreover, the pre-collected data are usually non-interactive, which does not consider the real-time responses of collaborators. As a result, these methods usually perform unsatisfactorily in real HRI scenarios. To solve this problem, in this paper, we propose a novel Continual Learning (CL) approach for probabilistic HMP which makes the robot continually learns during its interaction with collaborators. The proposed approach consists of two steps. First, we leverage a Bayesian Neural Network to model diverse uncertainties of observed human motions for collecting online interactive data safely. Then we take Experience Replay and Knowledge Distillation to elevate the model with new experiences while maintaining the knowledge learned before. We first evaluate our approach on a large-scale benchmark dataset Human3. 6m. The experimental results show that our approach achieves a lower prediction error compared with the baselines methods. Moreover, our approach could continually learn new motion patterns without forgetting the learned knowledge. We further conduct real-scene experiments using Kinect DK. The results show that our approach can learn the human kinematic model from scratch, which effectively secures the interaction.

ICML Conference 2022 Conference Paper

Greedy based Value Representation for Optimal Coordination in Multi-agent Reinforcement Learning

  • Lipeng Wan 0003
  • Zeyang Liu 0001
  • Xingyu Chen
  • Xuguang Lan
  • Nanning Zheng 0001

Due to the representation limitation of the joint Q value function, multi-agent reinforcement learning methods with linear value decomposition (LVD) or monotonic value decomposition (MVD) suffer from relative overgeneralization. As a result, they can not ensure optimal consistency (i. e. , the correspondence between individual greedy actions and the best team performance). In this paper, we derive the expression of the joint Q value function of LVD and MVD. According to the expression, we draw a transition diagram, where each self-transition node (STN) is a possible convergence. To ensure the optimal consistency, the optimal node is required to be the unique STN. Therefore, we propose the greedy-based value representation (GVR), which turns the optimal node into an STN via inferior target shaping and eliminates the non-optimal STNs via superior experience replay. Theoretical proofs and empirical results demonstrate that given the true Q values, GVR ensures the optimal consistency under sufficient exploration. Besides, in tasks where the true Q values are unavailable, GVR achieves an adaptive trade-off between optimality and stability. Our method outperforms state-of-the-art baselines in experiments on various benchmarks.

ICRA Conference 2021 Conference Paper

Probabilistic Human Motion Prediction via A Bayesian Neural Network

  • Jie Xu
  • Xingyu Chen
  • Xuguang Lan
  • Nanning Zheng 0001

Human motion prediction is an important and challenging topic that has promising prospects in efficient and safe human-robot-interaction systems. Currently, the majority of the human motion prediction algorithms are based on deterministic models, which may lead to risky decisions for robots. To solve this problem, we propose a probabilistic model for human motion prediction in this paper. The key idea of our approach is to extend the conventional deterministic motion prediction neural network to a Bayesian one. On one hand, our model could generate several future motions when given an observed motion sequence. On the other hand, by calculating the Epistemic Uncertainty and the Heteroscedastic Aleatoric Uncertainty, our model could tell the robot if the observation has been seen before and also give the optimal result among all possible predictions. We extensively validate our approach on a large scale benchmark dataset Human3. 6m. The experiments show that our approach performs better than deterministic methods. We further evaluate our approach in a Human-Robot-Interaction (HRI) scenario. The experimental results show that our approach makes the interaction more efficient and safer.

ICRA Conference 2020 Conference Paper

Navigation Command Matching for Vision-based Autonomous Driving

  • Yuxin Pan
  • Jianru Xue
  • Pengfei Zhang 0005
  • Wanli Ouyang
  • Jianwu Fang
  • Xingyu Chen

Learning an optimal policy for autonomous driving task to confront with complex environment is a long- studied challenge. Imitative reinforcement learning is accepted as a promising approach to learn a robust driving policy through expert demonstrations and interactions with environments. However, this model utilizes non-smooth rewards, which have a negative impact on matching between navigation commands and trajectory (state-action pairs), and degrade the generalizability of an agent. Smooth rewards are crucial to discriminate actions generated from sub-optimal policy. In this paper, we propose a navigation command matching (NCM) model to address this issue. There are two key components in NCM, 1) a matching measurer produces smooth navigation rewards that measure matching between navigation commands and trajectory; 2) attention-guided agent performs actions given states where salient regions in RGB images (i. e. roadsides, lane markings and dynamic obstacles) are highlighted to amplify their influence on the final model. We obtain navigation rewards and store transitions to replay buffer after an episode, so NCM is able to discriminate actions generated from suboptimal policy. Experiments on CARLA driving benchmark show our proposed NCM outperforms previous state-of-the- art models on various tasks in terms of the percentage of successfully completed episodes. Moreover, our model improves generalizability of the agent and obtains good performance even in unseen scenarios.

ICRA Conference 2019 Conference Paper

Dual Refinement Network for Single-Shot Object Detection

  • Xingyu Chen
  • Xiyuan Yang
  • Shihan Kong
  • Zhengxing Wu
  • Junzhi Yu 0001

Object detection methods fall into two categories, i. e. , two-stage and single-stage detectors. The former is characterized by high detection accuracy while the latter usually has a considerable inference speed. Hence, it is imperative to fuse their merits for a better accuracy vs. speed trade-off. To this end, we propose a dual refinement network (DRN) to boost the performance of the single-stage detector. Inheriting from the advantages of two-stage approaches (i. e. , two-step regression and accurate features for detection), anchor refinement and feature offset refinement are conducted in a novel anchor-offset detection, where the detection head is comprised of deformable convolutions. Moreover, to leverage contextual information for describing objects, we design a multi-deformable head, in which multiple detection paths with different receptive field sizes devote themselves to detecting objects. Extensive experiments on PASCAL VOC and ImageNet VID datasets are conducted, and we achieve a state-of-the-art detection performance in terms of both accuracy and inference speed.

ICML Conference 2019 Conference Paper

Proportionally Fair Clustering

  • Xingyu Chen
  • Brandon Fain
  • Liang Lyu 0001
  • Kamesh Munagala

We extend the fair machine learning literature by considering the problem of proportional centroid clustering in a metric context. For clustering n points with k centers, we define fairness as proportionality to mean that any n/k points are entitled to form their own cluster if there is another center that is closer in distance for all n/k points. We seek clustering solutions to which there are no such justified complaints from any subsets of agents, without assuming any a priori notion of protected subsets. We present and analyze algorithms to efficiently compute, optimize, and audit proportional solutions. We conclude with an empirical examination of the tradeoff between proportional solutions and the k-means objective.

IROS Conference 2018 Conference Paper

TSSD: Temporal Single-Shot Detector Based on Attention and LSTM

  • Xingyu Chen
  • Zhengxing Wu
  • Junzhi Yu 0001

Temporal object detection has attracted significant attention, but most popular methods can not leverage the rich temporal information in video or robotic vision. Although many different algorithms have been developed for video detection task, real-time online approaches are frequently deficient. In this paper, based on attention mechanism and convolutional long short-term memory (ConvLSTM), we propose a temporal single-shot detector (TSSD)for robotic vision. Distinct from previous methods, we aim to temporally integrate pyramidal feature hierarchy using ConvLSTM, and design a novel structure including a high-level ConvLSTM unit as well as a low-level one (HL-LSTM)for multi-scale feature maps. Moreover, we develop a creative temporal analysis unit, namely, ConvLSTM-based attention and attention-based ConvLSTM (A&CL), in which the ConvLSTM-based attention is specially tailored for background suppression and scale suppression while the attention-based ConvLSTM temporally integrates attention-aware features. Finally, our method is evaluated on ImageNet VID dataset. Extensive comparisons on detection performance confirm the superiority of the proposed approach, and the developed TSSD achieves a considerably enhanced accuracy vs. speed trade-off, i. e. , 64. 8% mAP vs. 27 FPS.

TCS Journal 2009 Journal Article

Semi-online machine covering for two uniform machines

  • Xingyu Chen
  • Leah Epstein
  • Zhiyi Tan

The machine covering problem deals with partitioning a sequence of jobs among a set of machines, so as to maximize the completion time of the least loaded machine. We study a semi-online variant, where jobs arrive one by one, sorted by non-increasing size. The jobs are to be processed by two uniformly related machines, with a speed ratio of q ≥ 1. Each job has to be processed continuously, in a time slot assigned to it on one of the machines. This assignment needs to be performed upon the arrival of the job. The length of the time slot, which is required for a specific job to run on a given machine, is equal to the size of the job divided by the speed of the machine. We give a complete competitive analysis of this problem by providing an algorithm of the best possible competitive ratio for every q ≥ 1. We first give a tight analysis of the performance of a natural greedy algorithm L P T for the problem. To achieve the best possible performance for the semi-online problem, we use a combination of L P T, together with two alternative algorithms which we design. The new algorithms attain the best possible competitive ratios in the two intervals q ∈ ( 1, 1. 5 ) and q ∈ ( 2. 4856, 1 + 3 ), respectively, whereas the greedy algorithm has the best possible competitive ratio for any other q ≥ 1.

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