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Partial Solution Operator Discretization-Based Methods for Efficiently Computing Least-Damped Eigenvalues of Large Time Delayed Power systems

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CSEE Journal of Power and Energy systems 2025年第2期11卷 671-682页

作者： Hua Ye Xiaofan Jia Muyang Liu Yutian Liu Sicong Zhang Key Laboratory of Power System Intelligent Dispatch and Control of Ministry of EducationShandong UniversityJinan 250061China School of Electrical Engineering Xinjiang UniversityUrumqi 830046China State Grid Jiangsu Electric Power Research Institute Nanjing 211103China

To investigate impact of time delays on the small signal stability of power systems, the least-damped eigenvalues with the smallest damping ratios have been calculated by eigen-analysis methods based on Solution Operator Discretization (SOD) with Pseudo-Spectral collocation (PS) and Implicit Runge-Kutta (IRK) methods. This paper evolves SOD-PSIIRK into their partial counterparts, i.e., PSOD-PSIIRK, with greatly enhanced efficiency and reliability in analyzing large-scale time delayed power systems. Compared with SOD-PSIIRK, PSOD-PSIIRK are characterized in constructing low order discretization matrices of solution operator as well as efficiently and directly solving the embedded Matrix-Inverse-Vector Products (MIVPs). The dimensions of the discretization matrices of solution operator are largely reduced as only the retarded state variables are discretized, rather than all state variables as in SOD-PSIIRK. Meanwhile, the proposed PSOD-PSIIRK optimize the most computationally expensive operations in SOD-PSIIRK by avoiding the iterative solutions to the two embedded MIVPs. PSOD-PS/IRK directly and efficiently compute the MIVPs via factorizing the Kronecker product-like discretization matrices of the solution operator into Schur complements. The Central China-North China ultra-high-voltage power grid with 80577 state variables serves to validate the proposed PSOD-PSIIRK and shows that compared with SOD-PSIIRK, the computational time consumed by PSOD-PSIIRK is cut down by 49.96 times without loss of any accuracy.

关键词： Eigenvalue analysis low frequency oscillation Schur complement decomposition small signal stability solution operator discretization spectral discretization time delay wide-area measurement system

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Online Optimization in Power systems With High Penetration of Renewable Generation:Advances and Prospects

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IEEE/CAA Journal of Automatica Sinica 2023年第4期10卷 839-858页

作者： Zhaojian Wang Wei Wei John Zhen Fu Pang Feng Liu Bo Yang Xinping Guan Shengwei Mei Key Laboratory of System Control and Information Processing Ministry of Education of ChinaDepartment of AutomationShanghai Jiao Tong UniversityShanghai 200240China State Key Laboratory of Power System and the Department of Electrical Engineering Tsinghua UniversityBeijing 100084China Institute of High Performance Computing(IHPC) Agency for Science Technology and Research(A*STAR)Singapore 138632Singapore

Traditionally,offline optimization of power systems is acceptable due to the largely predictable loads and reliable *** increasing penetration of fluctuating renewable generation and internet-of-things devices allowing for fine-grained controllability of loads have led to the diminishing applicability of offline optimization in the power systems domain,and have redirected attention to online optimization ***,online optimization is a broad topic that can be applied in and motivated by different settings,operated on different time scales,and built on different theoretical *** paper reviews the various types of online optimization techniques used in the power systems domain and aims to make clear the distinction between the most common techniques *** particular,we introduce and compare four distinct techniques used covering the breadth of online optimization techniques used in the power systems domain,i.e.,optimization-guided dynamic control,feedback optimization for single-period problems,Lyapunov-based optimization,and online convex optimization techniques for multi-period ***,we recommend some potential future directions for online optimization in the power systems domain.

关键词： optimization Lyapunov optimization online convex optimization online optimization optimization-guided control

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Dynamic synchronous motion accuracy measurement and estimation for a five-axis mirror milling system

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Science China(Technological Sciences) 2023年第3期66卷 689-705页

作者： XU Kun TANG XinYu BI QingZhen YU YangBo QIAN DeHou JI YuLei State Key Laboratory of Mechanical System and Vibration School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240China Shanghai TOP Numerical Control Technology Co. Ltd.Shanghai 201100China

A mirror milling system(MMS)comprises two face-to-face five-axis machine tools,one for the cutting spindle and the other for the support *** it is essential to maintain the cutter and support coaxial during the cutting process,synchronous motion accuracy is the key index of the *** paper proposed a novel method for measuring and estimating the synchronous motion accuracy of the dual five-axis machine *** method simultaneously detects errors in the tool center point(TCP)and tool axis direction(TAD)during synchronous *** implement the suggested method,a measurement device,with five high-precision displacement sensors was developed.A kinematic model was then developed to estimate the synchronous motion accuracy from the displacement sensor *** screw theory was used to obtain the analytical expression of the inverse kinematic model,and the synchronous motion error was compensated and adjusted based on the inverse kinematic model of the dual five-axis machine *** and TAD quasi-static errors,such as geometric and backlash errors,were first *** adjusting the servo parameters,the dynamic TCP and TAD errors,such as gain mismatch and reversal spike,were also *** proposed method and device were tested in a large MMS,and the measured quasi-static and dynamic errors were all reduced when the compensation and adjustment method was *** Carlo simulations were also used to estimate the uncertainty of the proposed scheme.

关键词： mirror milling synchronous motion error five-axis machine tool measurement dynamic accuracy

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Modeling and Experimental Study of an Open Two-Phase Loop Driven by Osmotic Pressure and Capillary Force

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Frontiers in Heat and Mass Transfer 2025年第1期23卷 55-70页

作者： Hanli Bi Zheng Peng Chenpeng Liu Zhichao Jia Guoguang Li Yuandong Guo Hongxing Zhang Jianyin Miao National Key Laboratory of SpacecraftThermal Control Beijing Institute of Spacecraft System EngineeringChina Academy of Space TechnologyBeijing100094China School of Aeronautical Science and Engineering Beihang UniversityBeijing100083China School of Energy and Environment Engineering University of Science and Technology BeijingBeijing100083China

As space technology advances,thermal control systems must effectively collect and dissipate heat from distributed,multi-source *** heat pipe is a highly reliable two-phase heat transfer component,but it has several limitations when addressing multi-source heat *** by the transport and heat dissipation system of plants,large trees achieve stable and efficient liquid supply under the influence of two driving forces:capillary force during transpiration in the leaves(pull)and root pressure generated by osmotic pressure in the roots(push).The root pressure provides an effective liquid supply with a driving force exceeding 2 MPa,far greater than the driving force in conventional capillary-pumped two-phase *** has shown that osmotic heat pipes offer a powerful driving force,and combining osmotic pressure with capillary force has significant ***,this paper designs a multi-evaporator,dual-drive two-phase loop,using both osmotic pressure and capillary force to solve the multi-source heat dissipation ***,a transmembrane water flux model for the osmotic pressure-driven device was established to predict the maximum heat transfer capacity of the dual-drive two-phase ***,an experimental setup for a multi-evaporator“osmotic pressure+capillary force”dual-drive two-phase loop was constructed,capable of transferring at least 235 W of power under a reverse gravity condition of 20 *** study also analyzed the effects of reverse gravity height,heat load distribution among the three evaporators,startup sequence,and varying branch resistances on the performance of the dual-drive two-phase loop.

关键词： Multi-heat sources osmotic pressure two-phase loop dual-drive loop heat pipe

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Adhesive surface-enhanced Raman scattering Cu-Au nanoassembly for the sensitive analysis of particulate matter

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Journal of Environmental Sciences 2023年第6期128卷 35-44页

作者： Ning Wang Zhiqiang Gan Fengkui Duan Hui Chen Chensheng Ma Jie Ji Zhenli Sun MOE Key Laboratory of Resources and Environmental System Optimization College of Environmental Science and EngineeringNorth China Electric Power UniversityBeijing 102206China State Key Joint Laboratory of Environment Simulation and Pollution Control School of EnvironmentTsinghua UniversityBeijing 100084China

Surface-enhanced Raman scattering(SERS)has been used in atmospheric aerosol detection as it enables the high-resolution analysis of particulate ***,its use in the detection of historical samples without damaging the sampling membrane while achieving effective transfer and the high-sensitivity analysis of particulate matter from sample films remains *** this study,a new type of SERS tape was developed,consisting of Au nanoparticles(NPs)on an adhesive double-sided Cu film(DCu).The enhanced electromagnetic field generated by the coupled resonance of the local surface plasmon resonances of AuNPs and DCu led to an enhanced SERS signal with an experimental enhancement factor of 10^(7).The AuNPs were semi-embedded and distributed on the substrate,and the viscous DCu layer was exposed,enabling particle *** substrates exhibited good uniformity and favorable reproducibility with relative standard deviations of 13.53%and 9.74%respectively,and the substrates could be stored for 180 days with no signs of signal *** application of the substrates was demonstrated by the extraction and detection of malachite green and ammonium salt particulate *** results demonstrated that SERS substrates based on AuNPs and DCu are highly promising in real–world environmental particle monitoring and detection.

关键词： Surfaced-enhanced Raman scattering Particulate matter Adhesive plasmonic coupling Electromagnetic enhancement

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Compression Format and Systolic Array Structure Co-design for Accelerating Sparse Matrix Multiplication in DNNs 24th

Compression Format and Systolic Array Structure Co-design f...

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24th International Conference on Algorithms and Architectures for Parallel Processing, ICA3PP 2024

作者： Cao, Yongxiang Jiang, Jixiang Zhao, Guocheng Wang, Wei Jiang, Hongxu Song, Yanfei School of Computer Science and Engineering Beihang University Beijing China Science and Technology on Complex System Control and Intelligent Agent Cooperation Laboratory Beijing China

ISBN: (纸本)9789819615445

The systolic array (SA) architecture is widely used in accelerator/AI chip design due to its excellent matrix multiplication acceleration effect. However, the mismatch between the traditional sparse matrix compression format and the SA architecture results in poor SA performance in computing sparse matrices. To solve the problem, we propose a method for co-designing the sparse compression format and SA architecture. This work proposes the Vector Group Compressed Coordinate (VGCC) data stream compression format and designs a sparse SA architecture based on hardware encoding and decoding. VGCC can handle data streams of any size without increasing the index bit width. The VGCC compression size is significantly smaller than general sparse compression formats such as COO/CSR. In a sparse matrix with a sparsity of 90%, it saves 67.13% of storage space compared to the state-of-the-art ECOO data stream compression format and achieves an average acceleration of 1.54 times. We also propose a VGCC-friendly SA architecture. Our SA architecture engine reduces logic consumption by 51.6% compared to Sparse TPU while achieving a 3.23x speedup. To mitigate the issue of high no-load rates in systolic arrays, we introduce a Data Transmission Priority (DTP) data matching algorithm. With sparsity levels ranging from 50% to 90%, the algorithm’s calculation speed is enhanced by 1.124x to 1.991x. We implemented a sparse DNN accelerator on an FPGA Zynq UltraScale+MPSoC ZCU102, utilizing the VGCC compression format proposed in this study for compressing input data. When compared to the S2 Engine, the accelerator achieved a 3.37x speed improvement in matrix multiplication with 75% sparsity, significantly enhancing the speed of sparse matrix multiplication. The accelerator achieved an average throughput of 1079.33GOP/s when inferencing DNNs. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2025.

关键词： Systolic arrays

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Low-carbon Economic Dispatch of Integrated Energy systems Considering Extended Carbon Emission Flow

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Journal of Modern Power systems and Clean Energy 2024年第6期12卷 1798-1809页

作者： Yumin Zhang Pengkai Sun Xingquan Ji Fushuan Wen Ming Yang Pingfeng Ye Shandong University of Science and Technology Qingdao 266590China Hainan Institute Zhejiang UniversitySanya 572000China School of Electrical Engineering Zhejiang UniversityHangzhou 310027China Key Laboratory of Power System Intelligent Dispatch and Control Shandong UniversityJinan 250061China

Carbon capture and storage(CCS)systems can provide sufficient carbon raw materials for power-to-gas(P2G)systems to reduce the carbon emission of traditional coal-fired units,which helps to achieve low-carbon dispatch of integrated energy systems(IESs).In this study,an extended carbon-emis-sion flow model that integrates CCS-P2G coordinated operation and low-carbon characteristics of an energy storage system(ESS)is *** the energy supply side,the coupling rela-tionship between CCS and P2G systems is established to realize the low-carbon economic operation of P2G *** the en-ergy storage side,the concept of"state of carbon"is introduced to describe the carbon emission characteristics of the ESS to ex-ploit the potential of coordinated low-carbon dispatch in terms of both energy production and *** addition,a low-car-bon economic dispatch model that considers multiple uncertain-ties,including wind power output,electricity price,and load de-mands,is *** solve the model efficiently,a parallel multidimensional approximate dynamic programming algo-rithm is adopted,while the solution efficiency is significantly im-proved over that of stochastic optimization without losing solu-tion accuracy under a multilayer parallel loop nesting *** low-carbon economic dispatch method of IESs is composed of the extended carbon emission flow model,low-car-bon economic dispatch model,and the parallel multidimension-al approximate dynamic programming *** effective-ness of the proposed method is verified on E14-H6-G6 and E57-H12-G12 systems.

关键词： Low-carbon economic dispatch carbon emission flow state of carbon parallel multidimensional approximate dynamic programming integrated energy system(IES)

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Distributed Secondary control of DC Microgrids with Operation Loss Reduction 43

Distributed Secondary Control of DC Microgrids with Operatio...

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43rd Chinese control Conference, CCC 2024

作者： Qiu, Maoxiang Zhang, Zhicheng Zuo, Zhiqiang Wang, Yijing Tianjin University Tianjin Key Laboratory of Intelligent Unmanned Swarm Technology and System School of Electrical and Information Engineering Tianjin300072 China Key Laboratory of System Control and Information Processing Ministry of Education Shanghai200240 China

ISBN: (纸本)9789887581581

In DC microgrids, current sharing and voltage regulation are two main objectives for real-time control, while the operation loss reduction is typically achieved by steady-state optimization. However, the ratio of current sharing is generally determined by the result of the centralized optimization in the classical hierarchical control framework of DC microgrids. Such an issue brings insufficient capability in respond to the changes of photovoltaic power and stored energy in the solar-powered energy systems. To handle this, this work proposes a distributed control scheme for single-bus DC microgrids. Under the proposed controller, the objectives of current sharing, bus voltage regulation and the total operation loss (converter loss and line loss) reduction can be guaranteed simultaneously. Moreover, the constraints on line currents and bus voltage are tackled as well. Finally, simulations verify the performance of the proposed control scheme. © 2024 Technical Committee on control Theory, Chinese Association of Automation.

关键词： Microgrids

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Infrared and Visible Image Fusion Based on Res2Net-Transformer Automatic Encoding and Decoding

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Computers, Materials & Continua 2024年第4期79卷 1441-1461页

作者： Chunming Wu Wukai Liu Xin Ma Key Laboratory of Modern Power System Simulation and Control&Renewable Energy Technology School of Electrical EngineeringNortheast Electric Power UniversityJilin132012China School of Electrical Engineering Northeast Electric Power UniversityJilin132012China School of Aeronautical Engineering Jilin Institute of Chemical TechnologyJilin132022China

A novel image fusion network framework with an autonomous encoder and decoder is suggested to increase thevisual impression of fused images by improving the quality of infrared and visible light picture fusion. The networkcomprises an encoder module, fusion layer, decoder module, and edge improvementmodule. The encoder moduleutilizes an enhanced Inception module for shallow feature extraction, then combines Res2Net and Transformerto achieve deep-level co-extraction of local and global features from the original picture. An edge enhancementmodule (EEM) is created to extract significant edge features. A modal maximum difference fusion strategy isintroduced to enhance the adaptive representation of information in various regions of the source image, therebyenhancing the contrast of the fused image. The encoder and the EEM module extract features, which are thencombined in the fusion layer to create a fused picture using the decoder. Three datasets were chosen to test thealgorithmproposed in this paper. The results of the experiments demonstrate that the network effectively preservesbackground and detail information in both infrared and visible images, yielding superior outcomes in subjectiveand objective evaluations.

关键词： Image fusion Res2Net-Transformer infrared image visible image

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Batch-subsample Prototype Network Classification Model for Imbalanced and Overlapping Data

Batch-subsample Prototype Network Classification Model for I...

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2022 Chinese Automation Congress, CAC 2022

作者： Shizhao, Wang Shaoguang, Shu Xueshi, Liu Beijing Institute of Control Engineering System Software Engineering Laboratory Beijing China

ISBN: (纸本)9781665465335

The classification of imbalanced and overlapping data is more difficult. When the number of categories is uneven and category areas are overlap, general neural network classifiers can only extract limited features from the data, which makes the model relies too much on existing samples, resulting in a low classification accuracy. Aiming at the above classification problem, this paper proposes a batch-subsample prototype network model. Based on the prototype network, the model achieves the separation of different categories in classification. In the training process, selecting each batch of training data by subsample method, so that the data for training is balanced each time, which effectively reduce the impact of category imbalance and overlapping on model training. This model is tested in the dataset NSL-KDD with the characteristics of imbalance and overlapping. The experimental results show that the classification accuracy of the batch-subsample prototype network (BSPN) model has been effectively improved, and the classification ability of minority categories also be better. To a certain extent, the model solves the problem that the neural network model has poor classification effect on imbalanced and overlapping data. Above all, the batch-subsample prototype network model can improve the classification accuracy in imbalanced and overlapping data, optimize the recognition rate of minority categories, and increase the classification robustness of the model, which is of great significance for imbalanced and overlapping data classification. © 2022 IEEE.

关键词： Classification (of information)

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