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39th Annual AAAI Conference on Artificial Intelligence, AAAI 2025

作者： Wang, Siyu Chen, Cailian Le, Xinyi Xu, Qimin Xu, Lei Zhang, Yanzhou Yang, Jie School of Electronics Information and Electrical Engineering Shanghai Jiao Tong University Shanghai China Key Laboratory of System Control and Information Processing Ministry of Education of China Shanghai China SJTU-Paris Elite Institute of Technology Shanghai Jiao Tong University Shanghai China Institute of Cyber Science and Technology Shanghai Jiao Tong University Shanghai China Shanghai Key Laboratory of Integrated Administration Technologies for Information Security Shanghai China University of Minnesota Twin Cities Saint Paul MN United States

ISBN: (纸本)157735897X

Computer-aided design (CAD) significantly enhances the efficiency, accuracy, and innovation of design processes by enabling precise 2D and 3D modeling, extensive analysis, and optimization. Existing methods for creating CAD models rely on latent vectors or point clouds, which are difficult to obtain and costly to store. Recent advances in Multimodal Large Language Models (MLLMs) have inspired researchers to use natural language instructions and images for CAD model construction. However, these models still struggle with inferring accurate 3D spatial location and orientation, leading to inaccuracies in determining the spatial 3D starting points and extrusion directions for constructing geometries. This work introduces CAD-GPT, a CAD synthesis method with spatial reasoning-enhanced MLLM that takes either a single image or a textual description as input. To achieve precise spatial inference, our approach introduces a 3D Modeling Spatial Mechanism. This method maps 3D spatial positions and 3D sketch plane rotation angles into a 1D linguistic feature space using a specialized spatial unfolding mechanism, while discretizing 2D sketch coordinates into an appropriate planar space to enable precise determination of spatial starting position, sketch orientation, and 2D sketch coordinate translations. Extensive experiments demonstrate that CAD-GPT consistently outperforms existing state-of-the-art methods in CAD model synthesis, both quantitatively and qualitatively. Copyright © 2025, Association for the Advancement of Artificial Intelligence (***). All rights reserved.

关键词： High level synthesis

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Challenges of Trajectory Planning with Integrator Models on Curved Roads ⁎

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IFAC-PapersOnLine 2020年第2期53卷 15588-15595页

作者： Jan Eilbrecht Olaf Stursberg Institute of Control and System Theory Department of Electrical Engineering and Computer Science University of Kassel 34121 Kassel Germany

In the context of trajectory planning for autonomous vehicles, a widely used vehicle model relies on linear integrator dynamics. We consider planning with this model type, with a focus on the requirement to account for curved road topologies. As our analysis reveals, this generally gives rise to non-convex, coupled constraints on the vehicle’s states and inputs, which impedes computationally efficient planning. We propose a method to resolve this issue by modification of the non-convex constraints. This modification is based on inner approximations of sub-level sets of nonlinear functions, which are obtained by quantifier elimination. The efficacy of the method is demonstrated in two example scenarios.

关键词： Autonomous driving trajectory planning vehicle dynamic systems constrained control

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Transient Response of High Dimensional Nonlinear Dynamic system for a Rotating Cantilever Twisted Plate

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Advances in Applied Mathematics and Mechanics 2020年第6期12卷 1542-1564页

作者： Yuxin Hao Xiaojun Gu Wei Zhang Jie Chen College of Mechanical Engineering&Beijing Key Laboratory of Electromechanical System Measurement and Control Beijing Information Science and Technology UniversityBeijing 100192China College of Mechanical Engineering Beijing University of TechnologyBeijing 100124China Architecture and Civil Engineering Research Center Shenzhen Research InstituteCity University of Hong KongShenzhenGuangdong 518055China

Dynamic transient responses of rotating twisted plate under the air-blast loading and step loading respectively considering the geometric nonlinear relationships are investigated using classical shallow shell *** applying energy principle,a novel high dimensional nonlinear dynamic system of the rotating cantilever twisted plate is derived for the first *** use of variable mode functions by polynomial functions according to the twist angles and geometric of the plate makes it more accurate to describe the dynamic system than that using the classic cantilever beam functions and the free-free beam *** comparison researches are carried out between the present results and other literatures to validate present model,formulation and computer *** of motion describing the transient high dimensional nonlinear dynamic response are reduced to a four degree of freedom dynamic system which expressed by out-plane *** effects of twisted angle,stagger angle,rotation speed,load intensity and viscous damping on nonlinear dynamic transient responses of the twisted plate have been ***’s important to note that although the homogeneous and isotropic material is applied here,it might be helpful for laminated composite,functionally graded material as long as the equivalent material parameters are obtained.

关键词： Cantilever twisted plate rotating blast loading transient response high dimensional nonlinear dynamics

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Hamiltonian Dynamics and Targeted Energy Transfer of a Grounded Bistable Nonlinear Energy Sink

SSRN

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SSRN 2022年

作者： Li, Shuangbao Zhou, Xinxing Chen, Jianen Research Institute of Science and Technology Civil Aviation University of China Tianjin300300 China College of Science Civil Aviation University of China Tianjin300300 China Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin300384 China

A two-degree-of-freedom nonlinear mechanical system describing a damped linear oscillator weakly coupled to a lightweight grounded bistable nonlinear energy sink is proposed to investigate the targeted energy transfer (TET) under asymmetric local nonlinear potentials. The Bogdanov-Takens bifurcations of equilibria are discussed to reflect the bistable and asymmetric characteristics of the system. Through projections of isoenergetic manifolds, the topological features of the Hamiltonian dynamics under $1:1$ internal resonance have been investigated, which induces conditions for energy localization and exchange. In the general case, the topological features of the Hamiltonian dynamics related to the nonlinear normal modes (NNMs) are classified by the Poincare map, the relations between the NNMs and the Hamiltonian dynamics have been interpreted through the frequency energy plots. The results show that introducing the asymmetric characteristics may enhance the TET and realize the complete TET. © 2022, The Authors. All rights reserved.

关键词： Degrees of freedom (mechanics)

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A Mixed Layer Height Parameterization in a 3-D Chemical Transport Model: Implications for Gas and Aerosol Simulations

SSRN

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SSRN 2024年

作者： Kim, Hyeonmin Park, Rokjin J. Hong, Song-You Park, Do-Hyeon Kim, Sang-Woo Oak, Yujin J. Feng, Xu Lin, Haipeng Fu, Tzung-May School of Earth and Environmental Sciences Seoul National University Seoul Korea Republic of Cooperative Institute for Research in Environmental Sciences University of Colorado Boulder United States Physical Sciences Laboratory The National Oceanic and Atmospheric Administration Earth System Research Laboratories Boulder United States Center for Sustainable Environment Research Korea Institute of Science and Technology Seoul Korea Republic of John A. Paulson School of Engineering and Applied Sciences Harvard University CambridgeMA United States State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control School of Environmental Science and Engineering Southern University of Science and Technology Guangdong Shenzhen China Shenzhen Institute of Sustainable Development Southern University of Science and Technology Guangdong Shenzhen China Seoul National University Korea Republic of

Vertical mixing within the planetary boundary layer (PBL) is crucial for determining surface-level pollutant concentrations. However, standard PBL schemes in chemical transport models (CTMs) often fail to adequately define the upper bounds of vertical mixing, particularly at night. This limitation frequently results in overestimated nocturnal concentrations of pollutants near the surface. To address this issue, we propose a parameterization of mixed layer height (MLH) derived from the Yonsei University (YSU) PBL scheme and thoroughly evaluate it by comparing simulations with various observations. We utilized the Weather Research and Forecasting model coupled with GEOS-Chem (WRF-GC) to simulate gas and aerosol distributions over South Korea during the Satellite Integrated Joint Monitoring of Air Quality (SIJAQ) campaign in 2021. The WRF-GC simulations incorporating the MLH parameterization improved the excessive titration of O3 and the overproduction of HNO3 and NO3- in the model. Consequently, the model performances in gaseous and aerosol simulations showed a better agreement with observations, with changes in normalized mean biases (NMBs) of NOX (from 50% to -27%), O3 (from -49% to -28%), NO3- (from 126% to 91%), NH4+ (from 113% to 85%), BC (from 322% to 135%), and PM2.5 (from 58% to 28%). © 2024, The Authors. All rights reserved.

关键词： Atmospheric chemistry

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PUGAN: Physical Model-Guided Underwater Image Enhancement Using GAN with Dual-Discriminators

arXiv

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arXiv 2023年

作者： Cong, Runmin Yang, Wenyu Zhang, Wei Li, Chongyi Guo, Chun-Le Huang, Qingming Kwong, Sam Institute of Information Science Beijing Jiaotong University Beijing100044 China School of Control Science and Engineering Shandong University Jinan250061 China Key Laboratory of Machine Intelligence and System Control Ministry of Education Jinan250061 China Beijing Key Laboratory of Advanced Information Science and Network Technology Beijing100044 China College of Computer Science Nankai University Tianjin300350 China School of Computer Science and Technology University of Chinese Academy of Sciences Beijing101408 China Key Laboratory of Intelligent Information Processing Institute of Computing Technology Chinese Academy of Sciences Beijing100190 China Peng Cheng Laboratory Shenzhen518055 China Department of Computer Science City University of Hong Kong Hong Kong City University of Hong Kong Shenzhen Research Institute Shenzhen51800 China

Due to the light absorption and scattering induced by the water medium, underwater images usually suffer from some degradation problems, such as low contrast, color distortion, and blurring details, which aggravate the difficulty of downstream underwater understanding tasks. Therefore, how to obtain clear and visually pleasant images has become a common concern of people, and the task of underwater image enhancement (UIE) has also emerged as the times require. Among existing UIE methods, Generative Adversarial Networks (GANs) based methods perform well in visual aesthetics, while the physical model-based methods have better scene adaptability. Inheriting the advantages of the above two types of models, we propose a physical model-guided GAN model for UIE in this paper, referred to as PUGAN. The entire network is under the GAN architecture. On the one hand, we design a Parameters Estimation subnetwork (Par-subnet) to learn the parameters for physical model inversion, and use the generated color enhancement image as auxiliary information for the Two-Stream Interaction Enhancement subnetwork (TSIE-subnet). Meanwhile, we design a Degradation Quantization (DQ) module in TSIE-subnet to quantize scene degradation, thereby achieving reinforcing enhancement of key regions. On the other hand, we design the Dual-Discriminators for the style-content adversarial constraint, promoting the authenticity and visual aesthetics of the results. Extensive experiments on three benchmark datasets demonstrate that our PUGAN outperforms state-of-the-art methods in both qualitative and quantitative metrics. The code and results can be found from the link of https://***/proj_***. © 2023, CC BY-NC-SA.

关键词： Discriminators

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LVRT During-fault-stage Equilibrium Point is Unnecessary for Renewable Grid-tied systems

LVRT During-fault-stage Equilibrium Point is Unnecessary for...

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Power system and Green Energy Conference (PSGEC)

作者： Yayao Zhang Min Cheng Meng Zhan Jiawei Yu Yihua Zhu Mingkang Wu State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan China Yunnan Power Grid China State Key Laboratory of HVDC Electric Power Research Institute China Southern Power Grid China National Energy Power Grid Technology R&D Centre Electric Power Research Institute China Southern Power Grid China Guangdong Provincial Key Laboratory of Intelligent Operation and Control for New Energy Power System Electric Power Research Institute China Southern Power Grid China

ISBN: (数字)9798350365573

ISBN: (纸本)9798350365580

Transient synchronous stability of renewable grid- tied systems is of paramount importance. Most of previous studies focused on the grid-tied converter in the low voltage ride through (LVRT) during-fault stage and performed stability analysis based on the belief that if the system has (or has no) a stable equilibrium point in the during-fault stage, the system will be stable (or unstable). Therefore, it has been broadly accepted that the existence and/or stability of equilibrium point in the during-fault stage is necessary. However, the whole LVRT contains four different stages and the during-fault stage is only one among them. The transient synchronous stability of whole system should be determined by the initial state in the late post-fault stage and the attraction basin of its equilibrium point. The late post-fault stage is essential for stability and all four stages are important. Clearly treating the during-fault stage as the whole LVRT stages makes the nonlinear switched dynamics problem be greatly simplified and, certainly, is incomplete. In order to clarify this point, this paper analyzes the influence of existence (or nonexistence) of equilibrium point in the during-fault stage on the transient synchronous stability of permanent magnet synchronous generator grid-tied system. We can find that the existence of an equilibrium point in the during-fault stage is only a sufficient condition, rather than a necessary condition. The theoretical analysis is also verified in the hardware-in-the-loop experiment Therefore, a large number of previous studies and results on the transient synchronous stability of renewable grid-tied systems are incomplete and questionable.

关键词： Sufficient conditions Stability criteria Switches Voltage Power system stability Synchronous generators Permanent magnets Nonlinear dynamical systems Transient analysis Magnetic switching

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Mission planning for repeated multi-spacecraft non-contact debris removal

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Chinese Journal of Aeronautics 2025年

作者： Hang XU Lujiang LIU Yanning GUO Youmin GONG Bin SONG Guangfu MA Department of Control Science and Engineering Harbin Institute of Technology Harbin 150001 China Shanghai Institute of Aerospace System Engineering Shanghai 201109 China Zhengzhou Research Institute Harbin Institute of Technology Zhengzhou 450000 China School of Mechanical Engineering and Automation Harbin Institute of Technology Shenzhen 518055 China

Non-contact debris removal methods are fuel-efficient in a single operation compared to contact-based strategies as spacecraft don’t need to match debris velocity. To comprehensively analyze this scheme, maneuvering schemes for maximum debris removal with minimum fuel consumption, including task assignment, sequence planning, and trajectory planning, must be formulated. The coupling between variables’ dimensions and optimization results in task assignment poses challenges, as debris removal is repetitive and uncertain, leading to a vast search space. This paper proposes a novel Greedy Randomized Adaptive Search Procedure with Large Neighborhood and Crossover Mechanisms (GRASP-LNCM) to address this problem. The hybrid dynamic iteration mechanism improves computational efficiency and enhances the optimality of results. The model innovatively considers unsuccessful single removal by using a quantitative method to assess removal percentage. In addition, to improve the efficiency of sequence and trajectory planning, a Suboptimal Search Algorithm (SSA) based on the Lambert property and accelerated Multi-Revolution Lambert Problem (MRLP) solving strategy is established. Finally, a real Iridium-33 debris removal mission is studied. The simulation demonstrates that the proposed algorithm achieves state-of-the-art performance in several typical scenarios. Compared to the contact-based scheme, the new one is simpler, saving more fuel under certain conditions.

关键词： Space debris Planning Non-contact method Optimization Greedy randomized adaptive search procedure

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Optimization of flight-to-gate assignment based on the passenger transfer demand 3

Optimization of flight-to-gate assignment based on the passe...

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2020 3rd International Conference on Computer Information science and Artificial Intelligence, CISAI 2020

作者： Tian, Le Li, Feng Chen, Xiaojing Wang, Hui State Key Laboratory of Rail Traffic Control and Safety Beijing Jiaotong University Beijing100044 China Institute of Transportation System Science and Engineering Beijing Jiaotong University Beijing100044 China

Flight-to-gate assignment problem is one of the focused issues in the field of air transportation management and optimization. This paper focuses on improving the used airport gate utilization and minimizing passenger transfer tension via making a reasonable flight-to-gate strategy. A two-stage mathematical model has been formulated. In the first stage, we are aiming to minimize the transfer tension of passengers. Based on the flight-to-gate assignment result from the first stage, the second stage aims to increase the utilization rate of airport gates. Finally, a flight-to-gate assignment plan is designed to certify the validity of our model. © Published under licence by IOP Publishing Ltd.

关键词： Combinatorial optimization

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Phase compensation method for low-frequency thermal noise suppression in space gravitational wave detection

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Applied Thermal engineering 2025年 277卷

作者： Qi Deng Hongjia Liu Lin-Cheng Han Hua Chen Changpeng Yang Xin Zhao Wen-Long Cheng Department of Thermal Science and Energy Engineering University of Science and Technology of China Hefei Anhui 230027 PR China National Key Laboratory of Spacecraft Thermal Control Beijing Institute of Spacecraft System Engineering Beijing 100094 PR China

Low-frequency thermal noise significantly affects the space gravitational wave detection accuracy of high-precision instruments within their sensitive frequency bands (1 mHz–100 mHz). Currently, the passive temperature noise suppression method, which relies on passive thermal control materials to mitigate thermal noise, has limitations in suppressing low-frequency periodic heat flux. In light of this, we propose a phase compensation-based approach for low-frequency thermal noise suppression, which counteracts thermal noise by generating a compensating heat flux with identical amplitude and nearly 180° phase offset to the input signal. In this paper, a two-dimensional model for temperature noise suppression based on heat flux phase compensation is established. By identifying the input heat flux and leveraging the heat transfer characteristics of low-frequency periodic heat flux, a compensation heat flux is generated. At the compensation interface, the compensation flux matches the input amplitude while maintaining a phase offset of approximately 180°. The validity of the model is experimentally verified. Moreover, numerical calculations are conducted by inputting multiple heat flux to investigate the suppression effect of the phase compensation method on low-frequency thermal noise. The results indicate that the phase compensation method can effectively control thermal noise with ultra-low frequency (1 mHz–100 mHz). At a frequency of 0.02 Hz, the temperature noise can be reduced to 0.0011 K/Hz 1/2 , and the thermal noise suppression efficiency exceeds 99.4 %. If combined with passive thermal control materials, the thermal noise can be further suppressed. For multi-frequency inputs, the compensation effects on individual frequency components remain mutually independent, achieving comparable noise reduction to single-frequency scenarios, demonstrating the frequency-domain decoupling mechanism of the phase compensation method. This study provides an innovative approach

关键词： Precision balances

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