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arXiv 2023年

作者： Xie, Wei Zhao, Zimeng Li, Shiying Zuo, Binghui Wang, Yangang Southeast University China The Key Laboratory of Measurement and Control of Complex Systems of Engineering Ministry of Education Nanjing China

Acquiring contact patterns between hands and nonrigid objects is a common concern in the vision and robotics community. However, existing learning-based methods focus more on contact with rigid ones from monocular images. When adopting them for nonrigid contact, a major problem is that the existing contact representation is restricted by the geometry of the object. Consequently, contact neighborhoods are stored in an unordered manner and contact features are difficult to align with image cues. At the core of our approach lies a novel hand-object contact representation called RUPs (Region Unwrapping Profiles), which unwrap the roughly estimated hand-object surfaces as multiple high-resolution 2D regional profiles. The region grouping strategy is consistent with the hand kinematic bone division because they are the primitive initiators for a composite contact pattern. Based on this representation, our Regional Unwrapping Transformer (RUFormer) learns the correlation priors across regions from monocular inputs and predicts corresponding contact and deformed transformations. Our experiments demonstrate that the proposed framework can robustly estimate the deformed degrees and deformed transformations, which makes it suitable for both nonrigid and rigid contact. © 2023, CC BY-NC-SA.

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Data-Based Optimal Tracking of Autonomous Nonlinear Switching systems

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IEEE/CAA Journal of Automatica Sinica 2021年第1期8卷 227-238页

作者： Xiaofeng Li Lu Dong Changyin Sun the School of Automation Southeast UniversityNanjing 210096 the Key Laboratory of Measurement and Control of Complex Systems of Engineering Ministry of EducationSoutheast UniversityNanjing 210096China the College of Electronics and Information Engineering Tongji UniversityShanghai 201804China

In this paper,a data-based scheme is proposed to solve the optimal tracking problem of autonomous nonlinear switching *** system state is forced to track the reference signal by minimizing the performance ***,the problem is transformed to solve the corresponding Bellman optimality equation in terms of the Q-function(also named as action value function).Then,an iterative algorithm based on adaptive dynamic programming(ADP)is developed to find the optimal solution which is totally based on sampled *** linear-in-parameter(LIP)neural network is taken as the value function *** the presence of approximation error at each iteration step,the generated approximated value function sequence is proved to be boundedness around the exact optimal solution under some verifiable ***,the effect that the learning process will be terminated after a finite number of iterations is investigated in this paper.A sufficient condition for asymptotically stability of the tracking error is ***,the effectiveness of the algorithm is demonstrated with three simulation examples.

关键词： Adaptive dynamic programming approximation error data-based control Q-learning switching system

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4D Myocardium Reconstruction with Decoupled Motion and Shape Model

arXiv

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arXiv 2023年

作者： Yuan, Xiaohan Liu, Cong Wang, Yangang Southeast University China The Key Laboratory of Measurement Control of Complex Systems of Engineering Ministry of Education Nanjing China

Estimating the shape and motion state of the myocardium is essential in diagnosing cardiovascular diseases. However, cine magnetic resonance (CMR) imaging is dominated by 2D slices, whose large slice spacing challenges inter-slice shape reconstruction and motion acquisition. To address this problem, we propose a 4D reconstruction method that decouples motion and shape, which can predict the inter-/intra- shape and motion estimation from a given sparse point cloud sequence obtained from limited slices. Our framework comprises a neural motion model and an end-diastolic (ED) shape model. The implicit ED shape model can learn a continuous boundary and encourage the motion model to predict without the supervision of ground truth deformation, and the motion model enables canonical input of the shape model by deforming any point from any phase to the ED phase. Additionally, the constructed ED-space enables pre-training of the shape model, thereby guiding the motion model and addressing the issue of data scarcity. We propose the first 4D myocardial dataset as we know and verify our method on the proposed, public, and cross-modal datasets, showing superior reconstruction performance and enabling various clinical applications. Copyright © 2023, The Authors. All rights reserved.

关键词： Motion estimation

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A High-Quality View Synthesis system for Sparse Rgb-D Input

SSRN

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SSRN 2024年

作者： Zhao, Ziyu Lu, Xiaobo Zhou, Sifan Chiang, Patrick Y.I.N. School of Automation Southeast University Nanjing China Key Laboratory of Measurement and Control of Complex Systems of Engineering Ministry of Education Southeast University Nanjing China Key Laboratory of ASIC and System Fudan University Shanghai China

Recent research in neural rendering has achieved impressive results in the field of novel view synthesis. However, high-quality view synthesis with sparse source views remains a challenging task, as the reduction in the number of source views significantly degrades the synthesis quality. In this paper, we present a novel view synthesis system that exploits RGB-D pairs from sparse source views. First, we introduce a two-branch feature extraction network to embed the geometric clues from depth maps into the texture information of color images and fuse it with regularized Fourier mapping features. Second, a distance-aware feature query method, which constructs multi-level feature maps, is proposed to ensure high-fidelity details across different distance views. Then, we apply an occupancy network to perform occupancy prediction on raw point cloud. By integrating occupancy probabilities and extracted features, we use a prediction network with geometric information as an additional input to obtain the color and density of sampled points, and synthesize the target view using neural volume rendering. To prevent model degradation and enhance efficiency, we design an efficient sampling strategy based on Gaussian Mixture Model. Moreover, we introduce pixel-wise local regularization and full-image global geometric regularization to optimize the model. Extensive experiments show that the proposed method can achieve the state-of-the-art results for novel view synthesis with sparse inputs, and the model performance has been significantly improved in different scenarios. © 2024, The Authors. All rights reserved.

关键词： Geometry

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Simulation Analysis of EFDC of Oil-Paper Insulation under Typical Electrode Structures with the Influence of Harmonic Voltage 9

Simulation Analysis of EFDC of Oil-Paper Insulation under Ty...

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9th Asia Conference on Power and Electrical engineering, ACPEE 2024

作者： Zhang, Ning Hao, Jian Xu, Jing Wang, Jixiang Chen, Houhe Liao, Ruijin Northeast Electric Power University Key Laboratory of Modern Power System Simulation and Control & Renewable Energy Technology Ministry of Education Jilin China Chongqing University State Key Laboratory of Power Transmission Equipment Technology School of Electrical Engineering Chongqing China

ISBN: (纸本)9798350309638

The primary sources of harmonic distortion in the new power system are a high percentage of access to power electronic equipment and a high percentage of renewable energy grid connections. These factors pose a major risk to the UHV converter transformer oil-paper insulation performance. However, the influence law of harmonic voltage on the electric field distribution characteristics (EFDC) of oil-paper insulation is still unclear;thus, the law of variation of spatial maximum electric field strength (SMEFS) under the action of harmonic voltage and the EFDC on the surface of oil-immersed insulating paper are investigated in this paper by building a two-dimensional simulation model of the electric field distribution of oil-paper insulation under ball-plate and cylinder-plate electrode structure. The results indicate that the two electrode structures' SMEFS are situated in the narrow oil gap between the oil-impregnated insulating paper and the high-voltage electrode;under the influence of the same harmonic components, the insulating paper's surface exhibits an inverse power function decay in the electric field distribution, with the cylinder-plate electrode decaying more quickly than the ball-plate electrode. Meanwhile, for both electrode structures, with the increase of the 5th and 13th harmonics, the SMEFS and the insulating paper surface field strength both increase linearly and are higher than that of the power frequency field strength, while for the 7th and 11th harmonics, the ball-plate electrode weakens the electric field and then increases it with the increase of the harmonic content, whereas the cylinder-plate electrode only increases the electric field. © 2024 IEEE.

关键词： Electric fields

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Prediction of Progressive Erosion Characteristics of Centrifugal Pump Blades Based on Dynamic Boundaries 8

Prediction of Progressive Erosion Characteristics of Centrif...

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8th International Conference on Pumps and Fans, ICPF 2024

作者： Shen, Xiaobo Li, Rennian Han, Wei Yang, Shiqi Bai, Lu Yang, Tao School of Energy and Power Engineering Lanzhou University of Technology Gansu Province China Key Laboratory of Advanced Pumps Valves and Fluid Control System of the Ministry of Education Lanzhou University of Technology Gansu Province China

The conventional method of fixed boundaries for predicting erosion inadequately reflects the erosion characteristics of centrifugal pumps under realistic operating conditions. In this research, we employ the dynamic boundary method, considering the influence of changes in wall morphology due to erosion on the flow field. We utilize the Euler-Lagrange approach and the E/CRC erosion model, incorporating a dynamic boundary geometry reconstruction strategy, to predict the erosion characteristics of the IS80-50-315 single-stage single-suction centrifugal pump. Solid-liquid two-phase flow calculations are conducted on the pump to predict erosion characteristics under varied operating conditions. The results show that the dynamic boundary-based progressive erosion prediction method realistically forecasts the erosion characteristics of the overflow wall and captures the evolution of blade morphology with erosion time. Erosion intensity on the blade suction surface significantly surpasses that on the pressure surface, guided by particle distribution characteristics in the centrifugal pump flow channel. Particle diameter primarily influences the erosion position of centrifugal pump blades;smaller particles induce erosion in the middle region of the blade, while an increase in particle diameter shifts the severe erosion position towards the impeller outlet direction. At a consistent particle diameter, higher particle concentrations correspond to elevated erosion rates in the blade area. We establish a relationship between the blade mass loss rate and erosion time during 2500 hours of pump operation at the design condition, introducing the blade mass loss rate for convenient assessment and prediction of blade damage in the centrifugal pump. © 2024 Institute of Physics Publishing. All rights reserved.

关键词： Two phase flow

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Data-Driven Frequency Regulation Method for Multi-Terminal HVDC Grids

Data-Driven Frequency Regulation Method for Multi-Terminal H...

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Youth Academic Annual Conference of Chinese Association of Automation (YAC)

作者： Panxiao Yong Yubin Jia Jun Guo Jun Zhou Zhimin Liu School of Automation Southeast University Nanjing China Key Laboratory of Measurement and Control of Complex System of Engineering Ministry of Education Southeast University Nanjing China

High voltage direct current (HVDC) lines allow low-loss transmission over long distances. The multi-terminal HVDC network consists of multiple terminals connected by HVDC lines, and each area shares the frequency reserve. Through secondary frequency control, the frequency of AC and DC areas can be regulated back to the set point when the system frequency has deviated. In this paper, a data-driven model predictive control (MPC) strategy is proposed. The Kooman operator is used to obtain the high-dimensional linear model of a nonlinear system, and the Deep Learning method is used to approximate the infinite-dimensional Koopman operator. The nominal MPC is used for optimization and control, and the optimal problem is solved for the Koopman linearized system. The optimal control is applied to the original nonlinear system. Simulation results show the effectiveness of the proposed method.

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Non-convex Optimization Based On Deep Koopman Operator

Non-convex Optimization Based On Deep Koopman Operator

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Youth Academic Annual Conference of Chinese Association of Automation (YAC)

作者： Jun Guo Yubin Jia Panxiao Yong Jun Zhou Zhimin Liu School of Automation Southeast University Nanjing China Key Laboratory of Measurement and Control of Complex System of Engineering Ministry of Education Southeast University Nanjing China

Non-convex optimization problems are prevalent in various fields, and finding the global optimal solution for such problems remains challenging. This paper proposes an optimization method based on deep Koopman operator, which leverages the power of deep neural networks to provide a data-driven architecture for the Koopman function. The Koopman operator is used to linearly represent non-convex problems, and the proposed method utilizes model predictive control to optimize the resulting linear systems. Simulation results show that this method can solve the non-convex optimization problem effectively, quickly and accurately, while obtaining the global optimal solution.

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Study in Gas-Phase Agglomeration Characteristics of Spiral Flow Gas-Liquid Multiphase Pump 8

Study in Gas-Phase Agglomeration Characteristics of Spiral F...

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8th International Conference on Pumps and Fans, ICPF 2024

作者： Han, Wei Guo, Xuanchen Feng, Huiming He, Chunpei Zhang, Yukun Xie, Wenqi College of Energy and Power Engineering Lanzhou University of Technology Lanzhou730050 China Key Laboratory of Advanced Pumps Valves and Fluid Control System of the Ministry of Education Lanzhou University of Technology Lanzhou730050 China

The spiral flow gas-liquid mixed transport pump experiences gas phase accumulation in the impeller flow passage, leading to blockage and a decrease in pumping performance. To understand the rules and mechanisms of gas phase aggregation in the spiral flow gas-liquid mixed transport pump, numerical calculations based on the Eulerian multiphase flow model and SST k - ω turbulent flow model were conducted. The effects of different gas volume fractions, speeds, and liquid phase viscosities on the pump were explored, and the external characteristics, flow characteristics, and gas phase aggregation processes in the impeller were analysed for these three variables. The results indicate that the head and efficiency of the pump gradually decrease with increasing gas volume fraction and liquid phase viscosity, while they increase with increasing speed. When the liquid phase viscosity changes from pure water to 50 times its viscosity, the gas phase aggregation at the impeller outlet decreases, resulting in reduced pressure and a smaller vortex region. The relative gas phase aggregation degree λ decreases from 0.5 to almost 0. When the gas volume fraction increases from 20% to 60%, the gas phase aggregation at the impeller outlet increases, the pressure difference between the impeller hub and the rim increases, and the vortex region expands, leading to an increase in λ by 8 times. When the speed increases from 3000 rpm to 5000 rpm, the gas phase aggregation at the impeller outlet increases, the pressure increases, and the vortex region expands, resulting in a 16-fold increase in λ . © 2024 Institute of Physics Publishing. All rights reserved.

关键词： Vortex flow

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General Simultaneous Localization and Mapping Scheme for mmWave Communication systems

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IEEE Internet of Things Journal 2024年第12期11卷 22521-22536页

作者： Du, Tao Yang, Jie Wen, Chao-Kai Xia, Shuqiang Jin, Shi Southeast University National Mobile Communications Research Laboratory Nanjing210096 China Southeast University Key Laboratory Of Measurement And Control Of Complex Systems Of Engineering Ministry Of Education The Frontiers Science Center For Mobile Information Communication And Security Nanjing210096 China Institute Of Communications Engineering National Sun Yat-sen University Kaohsiung80424 Taiwan Zte Corporation The State Key Laboratory Of Mobile Network And Mobile Multimedia Technology Shenzhen518055 China Southeast University National Mobile Communications Research Laboratory The Frontiers Science Center For Mobile Information Communication And Security Nanjing210096 China

Utilizing high-resolution antenna arrays and wide bandwidth of the millimeter-wave (mmWave) spectrum in 5G new radio (NR) mmWave communication systems holds the potential for high-throughput data transmission while enabling user localization and environmental mapping. However, the majority of existing simultaneous localization and mapping (SLAM) algorithms rely on methods akin to the extended Kalman filter for generating initial map features. These methods prove ineffective when the measurement dimension is insufficient. Furthermore, there is a notable absence of research exploring mmWave prototype systems to evaluate and compare the performance and viability of various SLAM algorithms. To address these challenges, we propose an innovative probability hypothesis density (PHD) generation scheme for birth events and have developed a prototype system. Our approach, referred to as PHD-SLAM, exhibits remarkable effectiveness even in scenarios where the measurement dimension falls short of map features. This means it can function seamlessly with only delay or angle information available. Additionally, we have designed a 28GHz mmWave beam scanning prototype system that leverages the 5G NR frame for accomplishing SLAM algorithms. Following this, we conducted extensive simulations and experimental evaluations to gauge the performance of several leading-edge SLAM algorithms under diverse mmWave circumstances, encompassing PHD-based and belief propagation (BP) SLAM algorithms. Our analysis reveals that both PHD and BP SLAM can achieve agent localization precision within a decimeter and mapping precision within a meter, capitalizing on the angle parameters of mmWave signals. While BP SLAM showcases reduced computational demand, its estimation precision is marginally inferior to that of PHD-SLAM. © 2014 IEEE.

关键词： Belief propagation

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