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arXiv 2025年

作者： Liu, Chenyang Chen, Keyan Zhao, Rui Zou, Zhengxia Shi, Zhenwei The Department of Aerospace Intelligent Science and Technology School of Astronautics The State Key Laboratory of Virtual Reality Technology and Systems Beihang University Beijing100191 China The Key Laboratory of Spacecraft Design Optimization and Dynamic Simulation Technologies Ministry of Education China Shanghai Artificial Intelligence Laboratory Shanghai200232 China Shen Yuan Honors College of Beihang University Beijing100191 China The Department of Electrical and Computer Engineering National University of Singapore Singapore117583 Singapore

Recently, generative foundation models have significantly advanced large-scale text-driven natural image generation and have become a prominent research trend across various vertical domains. However, in the remote sensing field, there is still a lack of research on large-scale text-to-image (text2image) generation technology. Existing remote sensing image-text datasets are small in scale and confined to specific geographic areas and scene types. Besides, existing text2image methods have struggled to achieve global-scale, multi-resolution controllable, and unbounded image generation. To address these challenges, this paper presents two key contributions: the Git-10M dataset and the Text2Earth foundation model. Git-10M is a global-scale image-text dataset comprising 10.5 million image-text pairs, 5 times larger than the previous largest one. The dataset contains essential resolution information and covers a wide range of geographic scenes and contains essential geospatial metadata, significantly surpassing existing datasets in both size and diversity. Building on Git-10M, we propose Text2Earth, a 1.3 billion parameter generative foundation model based on the diffusion framework to model global-scale remote sensing scenes. Text2Earth integrates a resolution guidance mechanism, enabling users to specify image resolutions. A dynamic condition adaptation strategy is proposed for training and inference to improve image generation quality. Text2Earth not only excels in zero-shot text2image generation but also demonstrates robust generalization and flexibility across multiple tasks, including unbounded scene construction, image editing, and cross-modal image generation. This robust capability surpasses previous models restricted to the basic fixed size and limited scene types. On the previous text2image benchmark dataset, Text2Earth outperfoms previous models with a significant improvement of +26.23 FID and +20.95% Zero-shot Cls-OA metric. Our project page is https://chen-y

关键词： Optical remote sensing

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Are Electric Vehicles Greener than Hybrid Electric Vehicles in Carsharing? Insights from Large-Scale Multi-Objective simulation-Optimization

SSRN

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SSRN 2024年

作者： Li, Yan Hu, Lu Li, Haobin Chew, Ek Peng Li, Hao Zhu, Juanxiu Department of Industrial Systems Engineering and Management National University of Singapore Singapore Centre of Excellence in Modelling and Simulation for Next Generation Ports National University of Singapore Singapore School of Transportation and Logistics Southwest Jiaotong University Chengdu China School of Traffic and Transportation Engineering Changsha University of Science and Technology Changsha China Hunan Key Laboratory of Smart Roadway and Cooperative Vehicle Infrastructure Systems Changsha University of Science and Technology Changsha China School of Management Xihua University Chengdu China

Hybrid electric vehicles (HEVs) are perceived as transitional products bridging the gap between fueled vehicles and electric vehicles (EVs) because people intuitively believe that EVs are more environmentally friendly than HEVs. But is this perception true in the context of carsharing services (CSSs)? This paper pioneers a general large-scale multi-objective simulation-optimization (MOSO) method to explore the values of deploying HEVs in CSSs. We firstly develop a physically logical simulation model, emulating operations of CSSs and capturing mesoscopic dynamics of shared vehicles in a link-based traffic network. This model adopts an event-driven discrete-event mechanism, enhancing efficiency while maintaining high fidelity. Subsequently, we design a simulation-optimization framework aimed at achieving Pareto optimality by jointly optimizing station capacity, fleet size, and trip pricing. The goal is twofold: to maximize operational profits and to minimize carbon emissions, thereby quantitatively analysing the potential of shared HEVs (SHEVs). To tackle the high-dimensional MOSO problem, we propose a general algorithm that incorporates the multiple gradient descent algorithm with the simultaneous perturbation stochastic approximation algorithm. Furthermore, we derive its analytical expression for bi-objective optimization problems. We theoretically prove and practically demonstrate its strong global convergence. The efficiency of this method was validated through large-scale computational experiments conducted in Chengdu, Sichuan Province, involving 66,710 decision variables. These experiments showcased the method's superiority over existing MOSO algorithms. Several groups of sensitivity experiments focusing on vehicle types and traffic scenarios reveal some interesting findings. (1) Regardless of the increase in travel distances, SHEVs, which can be viewed as shared EVs (SEVs) without range anxiety (RA), continue to primarily rely on electricity rather than fuel fo

关键词： Stochastic systems

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Numerical investigation on motion of an ellipsoidal particle inside confined microcavity flow

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Theoretical & Applied Mechanics Letters 2021年第1期11卷 47-51页

作者： Tianrou Miao Zuoli Xiao State Key Laboratory for Turbulence and Complex Systems College of EngineeringPeking UniversityBeijing 100871China HEDPS and Center for Applied Physics and Technology College of EngineeringPeking UniversityBeijing 100871China Beijing Innovation Center for Engineering Science and Advanced Technology Peking UniversityBeijing 100871China

The behaviors of a neutrally buoyant ellipsoidal particle in vortical flow confined by a microcavity are numerically studied using the Lattice-Boltzmann *** specific initial position,an isolated ellipsoid may develop a stable limit cycle orbit inside microcavity due to the interaction between particle and the carrier *** is observed that ellipsoidal particles of different shapes exhibit two different stable rotational modes depending on the initial orientation and lateral position.A prolate spheroid tends to enter a tumbling mode whereas an oblate spheroid is apt to achieve a rolling *** evolution of rotational velocities along the stable orbit is also analyzed for particles of different shapes.

关键词： Ellipsoidal particle Microcavity Particle-flow interaction Lattice Boltamann method

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Resonance contributions from χc0 in the charmless three-body hadronic B meson decays

arXiv

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arXiv 2023年

作者： Zhang, Ya-Lan Wang, Chao Lin, Yi Xiao, Zhen-Jun Faculty of Mathematics and Physics Huaiyin Institute of Technology Jiangsu Huaian223200 China Department of Physics Institute of Theoretical Physics Nanjing Normal University Jiangsu Nanjing210023 China Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Jiangsu Nanjing210023 China

Within the framework of perturbative QCD factorization, we investigate the nonfactorizable contributions to these factorization-forbidden Quasi-two-body decays B(s) → hχc0 → hπ+π−(K+K−) with h = π,K. We compare our predicted branching ratios for the B(s) → Kχc0 → Kπ+π−(K+K−) decay with available experiment data as well as predictions by other theoretical studies. The branching ratios of these decays are consistent with data and other theoretical predictions. In the Cabibbo-suppressed decays B(s) → hχc0 → hπ+π−(K+K−) with h = K¯0,π, however, the values of the branching ratios are the order of 10−7 and 10−8. The ratio Rχc0 between the decay B+ → π+χc0 → π+π+π− and B+ → K+χc0 → K+π+π− and the distribution of branching ratios for different decay modes in invariant mass are considered in this work. © 2023, CC BY.

关键词： Factorization

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Boundedness and continuity of maximal singular integrals and maximal functions on Triebel-Lizorkin spaces

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science China Mathematics 2020年第5期63卷 907-936页

作者： Feng Liu Qingying Xue Kozo Yabuta College of Mathematics and Systems Science Shandong University of Science and TechnologyQingdao 266590China Laboratory of Mathematics and Complex Systems(Ministry of Education of China) School of Mathematical SciencesBeijing Normal UniversityBeijing 100875China Research Center for Mathematical Science Kwansei Gakuin UniversitySanda 669-1337Japan

In this paper,we systematically study several classes of maximal singular integrals and maximal functions with rough kernels in Fβ(S^n-1),a topic that relates to the Grafakos-Stefanov *** boundedness and continuity o... 详细信息

关键词： maximal singular integrals maximal functions Fβ(S^n-1) Triebel-Lizorkin spaces Besov spaces

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非农业源排放增强大气二甲胺浓度并调节城市颗粒物成核

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science Bulletin 2023年第13期68卷 1447-1455,M0004页

作者：常运华凌清扬盖鑫磊袁相洋周升钱程凯毛鉴炯黄丹丹胡磬遥鲁君崔世杰高雅琴陆轶群朱亮谭稳郭松胡敏王红丽黄成黄汝锦张远航胡建林 Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters NUIST Center on Atmospheric EnvironmentNanjing University of Information Science&Technology(NUIST)Nanjing 210044China Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control Collaborative Innovation Center of Atmospheric Environment and Equipment TechnologyNanjing University of Information Science&TechnologyNanjing 210044China State Key Laboratory of Urban and Regional Ecology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention Department of Environmental Science and EngineeringFudan UniversityShanghai 200433China State Environmental Protection Key Laboratory of Formation and Prevention of Urban Air Pollution Complex Shanghai Academy of Environmental SciencesShanghai 200233China TOFWERK China Nanjing 211800China State Key Joint Laboratory of Environmental Simulation and Pollution Control College of Environmental Sciences and EngineeringPeking UniversityBeijing 100871China State Key Laboratory of Loess and Quaternary Geology Center for Excellence in Quaternary Science and Global ChangeKey Laboratory of Aerosol Chemistry&PhysicsInstitute of Earth and EnvironmentChinese Academy of SciencesXi’an 710061China

气态二甲胺(DMA)是大气新粒子生成的关键前体物,然而对其来源与空气和气候效应仍存在巨大争议.本研究率先对中国大气DMA浓度开展了南北跨区域与城市内部的走航观测.发现亚热带森林植物的DMA排放浓度可能南方远高于北方,同时记录到由工... 详细信息

气态二甲胺(DMA)是大气新粒子生成的关键前体物,然而对其来源与空气和气候效应仍存在巨大争议.本研究率先对中国大气DMA浓度开展了南北跨区域与城市内部的走航观测.发现亚热带森林植物的DMA排放浓度可能南方远高于北方,同时记录到由工业脉冲排放所导致的全球最高大气DMA浓度.在高度城市化的上海地区,DMA浓度自市中心向外围逐渐降低且与人口密度关联.源排放的直接测试进一步表明中国区域和城市内部的大气二甲胺都深受非农业源排放的影响.大气化学传输模式也证实,居民DMA排放主导了上海城市大气颗粒物数浓度的贡献.该研究将外场观测、源排放测试与模型模拟相结合,呈现了中国大气二甲胺的全生命周期,为颗粒物污染防治和气候变化评估提供了有用参考.

关键词： Newparticleformation Amines Volatile organic compounds Urbanatmosphere Non-agricultural sources

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A Novel Visual Perception Framework for Unmanned Aerial Vehicles: Challenges and Approaches

A Novel Visual Perception Framework for Unmanned Aerial Vehi...

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2021 China Automation Congress, CAC 2021

作者： Li, Xuan Duan, Haibin Mo, Hong Wang, Fei-Yue Department of Mathematics and Theories Peng Cheng Laboratory Shenzhen518055 China The State Key Laboratory of Virtual Reality Technology and Systems School of Automation Science and Electrical Engineering Beihang University Beijing100083 China The School of Electrical and Information Engineering Changsha University of Science and Technology Changsha410114 China The State Key Laboratory for Management and Control of Complex Systems Institute of Automation Chinese Academy of Sciences Beijing100190 China

ISBN: (纸本)9781665426473

Change detection (CD) is an important preprocessing process in visual perception. Due to the difficulties of collection and labeling images in water scnens, the design and validation of the change detection algorithm is more difficult than expected. In this paper, we present a novel visual perception framework based on parallel vision for unmanned aerial vehicle (UAV). The visual perception framework consists of artificial scenes, computational experiments and parallel execution. In artificial scenes, we construct a water scene and automatically generated pixel-level image annotation. Next, computational experiments are carried out on different domain dataset. The experiment results show that: 1) mixed images effectively improve the performance of change detection model;2) domain shift problems still greatly affect the algorithm performance. © 2021 IEEE

关键词： Change detection

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Heterogeneous Graph Reinforcement Learning for Dependency-aware Multi-task Allocation in Spatial Crowdsourcing

arXiv

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arXiv 2024年

作者： Zhao, Yong Zhu, Zhengqiu Gao, Chen Wang, En Huang, Jincai Wang, Fei-Yue College of Systems Engineering National University of Defense Technology Hunan Province Changsha410073 China BNRist Tsinghua University Beijing100084 China College of Computer Science and Technology Jilin University Changchun130012 China Key Laboratory of Symbolic Computation and Knowledge Engineering of Ministry of Education Jilin University Changchun130012 China State Key Laboratory for Management and Control of Complex Systems Institute of Automation Chinese Academy of Sciences Beijing100190 China

Spatial Crowdsourcing (SC) is gaining traction in both academia and industry, with tasks on SC platforms becoming increasingly complex and requiring collaboration among workers with diverse skills. Recent research works address complex tasks by dividing them into subtasks with dependencies and assigning them to suitable workers. However, the dependencies among subtasks and their heterogeneous skill requirements, as well as the need for efficient utilization of workers’ limited work time in the multi-task allocation mode, pose challenges in achieving an optimal task allocation scheme. Therefore, this paper formally investigates the problem of Dependency-aware Multi-task Allocation (DMA) and presents a well-designed framework to solve it, known as Heterogeneous Graph Reinforcement Learning-based Task Allocation (HGRL-TA). To address the challenges associated with representing and embedding diverse problem instances to ensure robust generalization, we propose a multi-relation graph model and a Compound-path-based Heterogeneous Graph Attention Network (CHANet) for effectively representing and capturing intricate relations among tasks and workers, as well as providing embedding of problem state. The task allocation decision is determined sequentially by a policy network, which undergoes simultaneous training with CHANet using the proximal policy optimization algorithm. Extensive experiment results demonstrate the effectiveness and generality of the proposed HGRL-TA in solving the DMA problem, leading to average profits that is 21.78% higher than those achieved using the metaheuristic methods. © 2024, CC BY-NC-ND.

关键词： Reinforcement learning

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A Lagrangian-based flame index for the transported probability density function method

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Theoretical & Applied Mechanics Letters 2022年第1期12卷 30-34页

作者： Zhen Lu Hua Zhou Zhuyin Ren Yue Yang Hong G.Im State Key Laboratory for Turbulent and Complex Systems College of EngineeringPeking UniversityBeijing 100871China BIC-ESAT Peking UniversityBeijing 100871China Clean Combustion Research Center King Abdullah University of Science and TechnologyThuwal 23955-6900Saudi Arabia Institute of Aero Engine Tsinghua UniversityBeijing 100084China HEDPS-CAPT Peking UniversityBeijing 100871China

We propose a new flame index for the transported probability density function(PDF) method. The flame index uses mixing flux projections of Lagrangian particles on mixture fraction and progress variable directions as the metrics to identify the combustion mode, with the Burke-Schumann solution as a reference. A priori validation of the flame index is conducted with a series of constructed turbulent partially premixed reactors. It indicates that the proposed flame index is able to identify the combustion mode based on the subgrid mixing information. The flame index is then applied the large eddy simulation/PDF datasets of turbulent partially premixed jet flames. Results show that the flame index separate different combustion modes and extinction correctly. The proposed flame index provides a promising tool to analyze and model the partially premixed flames adaptively.

关键词： Flame index Transported probability density function Partially premixed combustion

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Architecture analysis for avionics prognostics and health management system

Architecture analysis for avionics prognostics and health ma...

引用

Fault Detection, Supervision and Safety for Technical Processes (SAFEPROCESS), CAA Symposium on

作者： Runfeng Chen Yang Hu Yanze Hou Qian Xuesen Laboratory of Space Technology China Academy of Space Technology (CAST) Beijing China Science and Technology on Complex Aviation System Simulation Laboratory 9236 Beijing China

ISBN: (纸本)9781665401166

Prognostics and Health Management (PHM) has been researched on for recent years, and extensive studies have been done on hot topics into this field, such as diagnostics, prognostics, and decision making. However, how to evaluate PHM system architecture is still lacking. This is particularly important when designing avionics system equipped with PHM functions. We propose a general, time-variant architecture model that can simulate PHM system. Performance metrics are calculated to quantitatively evaluate the system architecture. This is useful to find differences of architectures in the earlier design stage in engineering. A case study is presented of the use of architecture modelling to show the effectiveness. And future works are discussed.

关键词： Measurement Analytical models System performance Fault detection Decision making systems architecture Aerospace electronics

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