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arXiv 2025年

作者： Cheng, Junfeng Yang, Xiao-Song School of Mathematics and Statistics Huazhong University of Science and Technology Wuhan430074 China Hubei Key Laboratory of Engineering Modeling and Scientific Computing Huazhong University of Science and Technology Wuhan430074 China

This paper enriches the topological horseshoe theory using finite subshift theory in symbolic dynamical systems, and develops an elementary framework addressing incomplete crossing and semi-horseshoes. Two illustrative examples are provided: one from the perturbed Duffing system and another from a polynomial system proposed by Chen, demonstrating the prevalence of semi-horseshoes in chaotic systems. Moreover, the semi-topological horseshoe theory enhances the detection of chaos and improves the accuracy of topological entropy estimation. Copyright © 2025, The Authors. All rights reserved.

关键词： Topology

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ThicknesVAE: Learning a Latera Prior for Clothed Human Body Reconsuction

ThicknesVAE: Learning a Latera Prior for Clothed Human Body ...

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2025 IEEE International Conference on Acoustics, Speech, and Signal Processing, ICASSP 2025

作者： Wu, Xiaotao Fan, Zhaoxin He, Huiguang Shen, Dinggang School of Biomedical Engineering State Key Laboratory of Advanced Medical Materials and Devices ShanghaiTech University Shanghai201210 China NeuBCI Group State Key Laboratory of Brain Cognition and Brain-inspired Intelligence Technology Institute of Automation Chinese Academy of Sciences Beijing China Beijing Advanced Innovation Center for Future Blockchain and Privacy Computing Institute of Artificial Intelligence Beihang University Beijing100191 China Beijing Academy of Blockchain and Edge Computing China Shanghai United Imaging Intelligence Co. Ltd. Shanghai200232 China Shanghai Clnical Research and Trial Center Shanghai201210 China

ISBN: (纸本)9798350368741

Sandwich-like structures have shown remarkable efficacy in clothed human reconstruction. However, these approaches often generate unrealistic side geometries due to inadequate handling of lateral regions. This paper addresses this limitation by incorporating the side geometry of clothed humans as a prior. We propose ThicknessVAE, a novel two-stage method that makes two key contributions: (1) We learn a prototype from point clouds for the lateral regions of clothed humans to extract common and detailed geometric features. (2) We utilize this prototype as a prior to transform geometric features into a thickness map associated with clothed human images, enabling refined normal integration for sandwich-like reconstruction methods. By seamlessly integrating our model into the sandwich-like reconstruction pipeline, we achieve highly realistic side views. Both qualitative and quantitative experiments demonstrate that our approach is comparable to state-of-the-art methods in terms of side-view realism. © 2025 IEEE.

关键词： 3D Human Reconsruction Normal Integraton Prior Learning

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Triangle Matters! TopDyG: Topology-aware Transformer for Link Prediction on Dynamic Graphs 34

Triangle Matters! TopDyG: Topology-aware Transformer for Lin...

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34th ACM Web Conference, WWW 2025

作者： Zhang, Xin Cai, Fei Zheng, Jianming Pan, Zhiqiang Chen, Wanyu Chen, Honghui Chen, Chonghao National Key Laboratory of Information Systems Engineering National University of Defense Technology Changsha China State Key Laboratory of Mathematical Engineering and Advanced Computing Wuxi China College of Electronic Countermeasures National University of Defense Technology Hefei China

ISBN: (纸本)9798400712746

Dynamic graph link prediction is widely utilized in the complex web of the real world, such as social networks, citation networks, recommendation systems, etc. Recent Transformer-based link prediction methods on dynamic graphs not only fail to model the fine-grained structures such as triangles with the vanilla Transformers in the graph serialization process, but also amplify the imbalanced distribution of graphs because of their over-estimation of high-degree nodes. To tackle these issues, we propose a Topology-aware Transformer on Dynamic Graph (TopDyG) for link prediction, consisting of a topology injected Transformer (Ti-Transformer) and a mutual information learning (Mi-Learning). The Ti-Transformer explores the explicit structure of serialized graphs, capturing the topological features. The Mi-Learning mines the relationship between nodes by modeling the mutual information with a prior knowledge, alleviating the over-estimation of high-degree nodes when applying the Transformer-based models for the dynamic graph link prediction task. Extensive experiments on four public datasets containing both transductive and inductive settings present the superiority of our proposal. In particular, TopDyG presents an improvement of 43.27% and 28.75% against the state-of-the-art baselines in terms of NDCG and Jaccard, respectively. The advantages are especially obvious on the high-density graphs. © 2025 Copyright held by the owner/author(s).

关键词： Dynamic graphs Link prediction Topology Transformer

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Research of Wedge-Shaped Bow to Ship Side Collision Based on Quasi-static and Dynamic Experiments

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Journal of Offshore Mechanics and Arctic engineering 2025年第5期147卷 051701页

作者： Qiu, Xiaoming Zhao, Yanjie Wang, Deyu State Key Laboratory of Ocean Engineering Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration School of Ocean and Civil Engineering Shanghai Jiao Tong University Shanghai 200240 China National Key Laboratory of Ship Structural Safety China Ship Scientific Research Center Wuxi Jiangsu 214125 China

A wedge-shaped bow above the waterline of a small size striking ship will cause serious damage to the side of a large size struck ship. Therefore, a penetrating indenter with the shape of a small ship bow top was applied in the quasi-static penetration and collision experiments to study the side collision of the two different size ships. The side structure of the large size struck ship was also simplified as a typical frame structure consists of a girder, stiffeners, and an outer plate. Material stress–strain properties were derived from tensile testing. Quasi-static experiments employed a hydraulic penetrating system, while dynamic impacts utilized a drop-weight machine to generate displacement–force curves. The experimental results were compared with the numerical simulation ones. The structural deformation process and force curves of different impact positions and velocities were also compared. Traditional empirical formulae were evaluated against experimental and numerical datasets, revealing limitations in predictive accuracy. Therefore, a rapid estimation method was proposed, leveraging the arithmetic superposition of simplified structural analysis results. The applicability of this approach was systematically assessed by some comparison cases of different velocities and structures. This methodology offers a practical engineering tool in scenarios involving moderate velocities and un-complex structures.

关键词： Computer simulation Ships dynamics of structures Collisions (Physics) collision experiment structural mechanics and foundation Deformation Displacement Wedges Simulation reliability of offshore structures and pipelines force prediction different size ship collision Girders

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Lagrangian simulation of bedload-sized particle trajectories at a 90° river confluence

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Earth Surface Processes and Landforms 2025年第6期50卷

作者： Ni, Yufang Moradi, Gelare Cao, Zhixian Lane, Stuart N. Changjiang River Scientific Research Institute Wuhan China State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University Wuhan China University of Lausanne Lausanne Switzerland

Whilst confluence hydrodynamics are now very well known, their morphodynamics are less so. This is particularly true for bedload transport, including the trajectories followed by bedload supplied to a confluence by the main channel or the tributary, and their interactions. Field measurement of this phenomenon is currently difficult. laboratory measurement allows study of gross effects, but not the detailed physics of the process. This paper applies a Lagrangian particle tracking model to a 90° discordant confluence, i.e. where the tributary enters the main channel at a height above the mainstream bed. The model was set up to represent the confluence of the Rhône and Avançon Rivers, Switzerland. The model is based upon a three-dimensional solution of the incompressible Navier-Stokes equations in the open-source toolbox OpenFOAM. It applies a Delayed Detached Eddy Simulation. Particle movement allows for coupled interactions between particles as well as between particles and the stream bed. Results show that as bedload arrives at the tributary mouth, there is size segregation. Some particles from the tributary fall rapidly to the mainstream bed and then travel along the main channel margin to the zone where bank-attached point bars commonly form. Others travel further into the main channel, notably if interactions between particles are allowed. The zone of maximum shear between the joining flows tends to have lower densities of particle tracks. There is sediment sorting at the junction with the very coarsest particles, due to interactions and momentum effects, and the very finest particles, due to greater ease of turbulent suspension, extending further into the main channel. © 2025 John Wiley & Sons Ltd.

关键词： Navier Stokes equations

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Metal-Organic frameworks for optical sensor arrays

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Progress in Materials Science 2025年 154卷

作者： Zhang, Xin Cui, Yuanjing Qian, Guodong State Key Laboratory of Silicon and Advanced Semiconductor Materials ZJU-Hangzhou Global Scientific and Technological Innovation Center School of Materials Science and Engineering Zhejiang University Hangzhou310030 China

Precisely identifying subtle structural distinctions among various analytes remains a crucial yet difficult endeavor, primarily due to their extensive diversity, structural resemblance, and the potential for mutual interference. Traditional sensors, which operate on the "lock-and-key" principle, offer high selectivity and specificity for detecting particular analytes. However, this design makes them unsuitable for the simultaneous detection of multiple analytes. Metal-organic frameworks (MOFs) have attracted considerable interest in the realm of optical sensor arrays due to their diverse metal nodes and ligands, as well as the guest species that can be encapsulated within their channels or pores. This versatility makes MOFs highly advantageous for developing multi-channel single-sensing-element sensor arrays. The primary emphasis of this comprehensive review is on the intrinsic structure-performance relationship and development status of MOF-based optical sensor arrays. First, this review offers a concise explanation of the underlying theory and operational steps involved in optical sensor arrays. Second, the construction strategies for cross-reactive sensing elements are thoroughly presented. Third, the applications of MOF-based optical sensor arrays in identifying and detecting target analytes are explored comprehensively. This includes their use in environmental monitoring, disease diagnosis, food quality assessment, and the analysis of complex systems. Finally, the existing limitations and future research opportunities concerning MOF-based optical sensor arrays are thoroughly examined. © 2025 Elsevier Ltd

关键词： Image matching

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Tunable Room-Temperature Phosphorescence in Hydrogen-Bonded Organic Crystals via H-Bonding Units

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Advanced Functional Materials 2025年

作者： Han, Xue Zheng, He-Qi Yang, Yu Cui, Yuanjing Qian, Guodong State Key Laboratory of Silicon and Advanced Semiconductor Materials ZJU-Hangzhou Global Scientific and Technological Innovation Center School of Materials Science and Engineering Zhejiang University Hangzhou310030 China

Organic room-temperature phosphorescence (RTP) materials with tunable emission colors, lifetime, and quantum yield have important implications for applications in optoelectronics, bioimaging, and anti-counterfeiting. Herein, a facile strategy is presented for multi-parameters switchable RTP by introducing second H-bonding units (SHUs) capable of adsorption and desorption, such as H2O and DMSO, into hydrogen-bonded organic crystals. It is found that the incorporation of H2O molecules into the HOC-PM-H2O structure establishes a robust hydrogen bonding network that stabilizes the triplet excited states, thereby suppressing non-radiative transitions and extending the phosphorescence lifetime to 904 ± 45 ms. In contrast, DMSO molecules in the HOC-PM-DMSO structure promote the separation of aggregate states, leading to a transition in phosphorescence from yellow-green to blue with a quantum yield of up to 63%. The RTP performance of HOC-PM-H2O and HOC-PM-DMSO can be reversibly switched by SHUs. By leveraging the temporal and spatial changes in lifetime and color, an information security system and afterglow displays activated by SHUs are developed. The SHUs-activated strategy not only provides a robust platform for revealing structure-property relationships but also offers a novel approach to designing advanced functional materials with specific luminescent properties. © 2025 Wiley-VCH GmbH.

关键词： Phosphorescence

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~ 350 W near-diffraction-limited Nd: YVO4 laser amplifier with thermal spherical aberration self-compensation

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Applied Physics B 2025年第6期131卷 1-8页

作者： Liu, Yang Qiu, Xiaoyan Liu, Bin Shen, Yuhong Chen, Liying Dong, Junyang Jin, Yiwen Peng, Yichao Chen, Jian Ju, Bingfeng Liu, Chong State Key Laboratory of Extreme Photonics and Instrumentation College of Optical Science and Engineering Zhejiang University Hangzhou China ZJU-Hangzhou Global Scientific and Technological Innovation Center Zhejiang University Hangzhou China Changzhou Inno Laser Technology Corporation Limited Changzhou China The State Key Laboratory of Fluid Power and Mechatronic Systems School of Mechanical Engineering Zhejiang University Hangzhou China

This study proposes a high-power, high-beam-quality 1064 nm Nd: YVO4 laser amplifier that employs self-compensating spherical aberration, based on 878 nm and 888 nm laser diode end-pumping. Thermal compensation of spherical aberration in the laser crystal is confirmed through wavefront measurement, and the impact of thermal distortion on beam quality is evaluated. The seed laser with an output power of 30 W is amplified to 385 W by employing a four-stage Nd: YVO4 amplifier. During amplification, the laser beam quality undergoes deterioration and compensation. When the output power decreased to ~ 350 W, the final beam quality factors are 1.21 in the horizontal direction and 1.25 in the vertical direction. The high average output power and near diffraction-limited laser beam demonstrate the potential applications of conventional bulk Nd: YVO4 crystals in high average power and high brightness laser sources.

关键词： High power lasers

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Location Privacy Preservation Crowdsensing With Federated Reinforcement Learning

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IEEE Transactions on Dependable and Secure computing 2025年第3期22卷 1877-1894页

作者： You, Zhichao Dong, Xuewen Liu, Ximeng Gao, Sheng Wang, Yongzhi Shen, Yulong Xidian University School of Computer Science and Technology The Engineering Research Center of Blockchain Technology Application and Evaluation Ministry of Education Xi'an710071 China Shaanxi Key Laboratory of Blockchain and Secure Computing Xi'an710071 China Fuzhou University College of Computer and Data Science Fuzhou350025 China Central University of Finance and Economics School of Information Beijing102206 China California State Polytechnic University Pomona Department of Computer Information Systems PomonaCA91768 United States Xidian University School of Computer Science and Technology Xi'an710071 China Shaanxi Key Laboratory of Network and System Security Xi'an710071 China

Crowdsensing has become a popular method of sensing data collection while facing the problem of protecting participants' location privacy. Existing location-privacy crowdsensing mechanisms focus on static tasks and participants without considering sensing tasks' time requirements and participants' mobility, which cannot achieve satisfactory collected data quality and task completion in crowdsensing with dynamic tasks and participants. Inspired by this, we proposed a location-preservation crowdsensing mechanism, FedSense, considering dynamic tasks and participants based on federated learning (FL) and reinforcement learning (RL). In FedSense, through RL's outstanding decision-making ability, participants select sensing tasks to perform by well-trained RL models without uploading location information to servers for task allocation. We propose an independent tasks selection environment that defines actions, states, and rewards of RL to enable FedSense to achieve satisfactory task completion and data quality while preserving location privacy. Besides, FedSense applies an asynchronous FL aggregation algorithm that reduces participants' network stabilization and device computing ability requirements. Analysis proves that participants' location information does not leave the local device during the model training and task selection process, effectively avoiding privacy leakage. Simulation shows that compared with existing location-preservation crowdsensing mechanisms, FedSense achieves the highest task completion and sensing accuracy for dynamic tasks and participants. © 2024 IEEE.

关键词： Data privacy

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Multi-frequency terahertz Smith–Purcell radiation via momentum-mismatch-driven quasi-bound states in the continuum

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Photonics Research 2025年第3期13卷 593-603页

作者： ZI-WEN ZHANG JUAN-FENG ZHU FENG-YUAN HAN XIAO LIN CHAO-HAI DU Center for Carbon-based Electronics School of ElectronicsPeking University State Key Laboratory of Advanced Optical Communication Systems and Networks School of ElectronicsPeking University Science Mathematicsand Technology (SMT)Singapore University of Technology and Design Interdisciplinary Center for Quantum Information State Key Laboratory of Extreme Photonics and InstrumentationZJU-Hangzhou Global Scientific and Technological Innovation CenterCollege of Information Science&Electronic EngineeringZhejiang University International Joint Innovation Center The Electromagnetics Academy at Zhejiang UniversityZhejiang University

Bound states in the continuum (BICs) have gained considerable attention for their ability to strengthen light–matter interactions,enabling applications in lasing,sensing,and *** properties also show great promise for intensifying free-electron ***,researchers realized momentum-mismatch-driven quasi-BICs in compound grating *** category of quasi-BICs exhibits high Q factors over a broad frequency *** this paper,we explore the possibility of achieving multi-frequency terahertz Smith–Purcell radiation empowered by momentum-mismatch-driven quasi-BICs in silicon compound grating *** leveraging the low-loss properties of silicon in the terahertz range,quasi-BICs are achieved through guided-mode resonance,delivering exceptionally high Q factors over a broad frequency *** broadband nature of these quasi-BICs enables efficient energy extraction from electron beams across varying voltages,while their multimode characteristics support simultaneous interactions with multiple modes,further boosting radiation *** findings demonstrate significant enhancement of free-electron radiation at multiple frequencies,addressing the limitations of narrowband methods and high-loss metallic *** integrating broadband performance with the advantages of low-loss dielectric platforms,this work advances the development of compact,tunable terahertz free-electron radiation sources and provides valuable insights into optimizing quasi-BIC systems for practical applications.

关键词： Light matter interactions Lithium niobate waveguides Nonlinear frequency conversion Q factor Quantum light sources Waveguide modes

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