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Robust Forecasting-Aided State Estimation Considering Uncertainty in Distribution System

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CSEE Journal of Power and Energy Systems 2024年第4期10卷 1632-1641页

作者： Dongchen hou Yonghui Sun linchuang Zhang sen Wang College of Energy and Electrical Engineering Hohai UniversityNanjing 210098China

With the development of the smart grid,the distribution system operation conditions become more complex and ***,due to the influence of observation outliers and uncertain noise statistics,it is more difficult to grasp the dynamic operation characteristics of distribution *** order to address these problems,by using projection statistics and the noise covariance updating technology based on the Sage-Husa noise estimator,for distribution power system with outliers and uncertain noise statistics,a robust adaptive cubature Kalman filter forecasting-aided state estimation method is proposed based on generalized-maximum likelihood type ***,an adaptive strategy,which can enhance the filtering accuracy under normal conditions,is *** the simulation part,the branch parameters and node load parameters of the test system are appropriately modified to simulate the asymmetry of the three-phase branch parameters and the asymmetry of the three-phase ***,through simulation experiments on the improved test system,it is verified that the robust forecasting-aided state estimation method,presented in this paper,can effectively perceive the actual operating state of the distribution network in different simulation scenarios.

关键词： Cubature Kalman filter distribution power system forecasting-aided state estimation projection statistics

An Improved Method for Approximating the Infinite-Horizon Value Function of the Discrete-Time Switched LQR Problem

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Journal of Systems Science & Complexity 2024年第1期37卷 22-39页

作者： hou Tan LI Yuanlong lin Zongli Department of Automation Shanghai Jiao Tong UniversityShanghai 200240China Key Laboratory of System Control and Information Processing Ministry of Education of ChinaShanghai 200240China Shanghai Engineering Research Center of Intelligent Control and Management Shanghai 200240China Charles L.Brown Department of Electrical and Computer Engineering University of VirginiaCharlottesvilleVA 22904-4743USA

This paper considers the problem of approximating the infinite-horizon value function of the discrete-time switched LQR *** particular,the authors propose a new value iteration method to generate a sequence of monotonically decreasing functions that converges exponentially to the value *** method facilitates us to use coarse approximations resulting from faster but less accurate algorithms for further value iteration,and thus,the proposed approach is capable of achieving a better approximation for a given computation time compared with the existing *** numerical examples are presented in this paper to illustrate the effectiveness of the proposed method.

关键词： Optimal control switched linear systems switched LQR problem.

Presentation of the Berry-Tabor conjecture in Levy plates

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Chinese Physics B 2024年第10期33卷 240-247页

作者： Chao Li Guo-lin hou School of Mathematical Sciences Inner Mongolia UniversityHohhot 010021China

The Berry-Tabor(BT)conjecture is a famous statistical inference in quantum chaos,which not only establishes the spectral fluctuations of quantum systems whose classical counterparts are integrable but can also be used to describe other wave *** this paper,the BT conjecture has been extended to Lévy *** predicted by the BT conjecture,level clustering is present in the spectra of Lévy *** consequence of level clustering is studied by introducing the distribution of nearest neighbor frequency level spacing ratios P(r),which is calculated through the analytical solution obtained by the Hamiltonian *** work investigates the impact of varying foundation parameters,rotary inertia,and boundary conditions on the frequency spectra,and we find that P(r)conforms to a Poisson distribution in all *** reason for the occurrence of the Poisson distribution in the Lévy plates is the independence between modal frequencies,which can be understood through mode functions.

关键词： Berry-Tabor conjecture frequency spectra Hamiltonian approach Lévy plates

Heat Transfer Characteristics of a Microchannel Heat Sink with Highly-Dense Micro-Jet Arrays

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Journal of Thermal Science 2024年第3期33卷 1148-1160页

作者： ZHANG Yu CHEN Xiaoyan MIAO lin CHEN Liang hou Yu State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an710049China Beijing Aerospace Technology Institute Beijing100083China

This paper proposed a new structure of highly-dense micro-jet arrays for hybrid jet-impingement/microchannel heat sinks(~120 jet per cm^(2) with jet width of 0.35 mm).Parametric study is performed to investigate the influence of structure and flow parameters on the convective heat transfer of water jet cooling in confined *** simulation results show that the optimal jet width,jet spacing and impingement distance are around 0.2 mm,0.2 mm and 0.3 mm,respectively,which can achieve a low thermal resistance as well as a relatively low pressure *** analysis of the heat transfer pathways shows that the micro-fin jet structures can extend the impinging heat transfer area and conduct a considerable proportion of heat,which can reach up to 38.9%with the Reynolds number ranging from 797.1 to *** heat transfer characteristics in the heat sink will shift from impingement dominated heat transfer to the channel-convection dominated heat transfer as the jet impingement distance increases.A correlation is proposed to predict the average Nusselt number on the stagnation area for the heat sink with different structure parameters,and the deviations of predictions from the numerical results are less than 10%.

关键词： hybrid heat sink impingement microchannel thermal management high heat flux

Machine Learning Analysis of Impact of Western US Fires on Central US Hailstorms

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Advances in Atmospheric Sciences 2024年第7期41卷 1450-1462页

作者： Xinming lin Jiwen FAN Yuwei ZHANG ZJason hou Pacific Northwest National Laboratory RichlandWA 99354USA Argonne National Laboratory LemontIL 60439USA

Fires,including wildfires,harm air quality and essential public services like transportation,communication,and *** fires can also influence atmospheric conditions,including temperature and aerosols,potentially affecting severe convective ***,we investigate the remote impacts of fires in the western United States(WUS)on the occurrence of large hail(size:≥2.54 cm)in the central US(CUS)over the 20-year period of 2001–20 using the machine learning(ML),Random Forest(RF),and Extreme Gradient Boosting(XGB)*** developed RF and XGB models demonstrate high accuracy(>90%)and F1 scores of up to 0.78 in predicting large hail occurrences when WUS fires and CUS hailstorms coincide,particularly in four states(Wyoming,South Dakota,Nebraska,and Kansas).The key contributing variables identified from both ML models include the meteorological variables in the fire region(temperature and moisture),the westerly wind over the plume transport path,and the fire features(i.e.,the maximum fire power and burned area).The results confirm a linkage between WUS fires and severe weather in the CUS,corroborating the findings of our previous modeling study conducted on case simulations with a detailed physics model.

关键词： wildfire severe convective storm hailstorm machine learning

Provably secure attribute-based authenticated encryption with keyword search from ideal lattices

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Science China(Information Sciences) 2024年第1期67卷 308-309页

作者： Lisha YAO lin hou Jian WENG Feixiang ZHAO College of Cyber Security Jinan University

A public-key authenticated encryption with keyword search(PAEKS)[1, 2] system overcomes the problem of an inside adversary forging searchable ciphertexts and guessing the keyword information from the given token. This system allows the sender to encrypt and authenticate a ***, traditional PAEKS schemes require the sender to specify the intended receiver in advance, losing much flexibility.

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Intelligent casting:Empowering the future foundry industry

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China Foundry 2024年第5期21卷 409-426页

作者： Jin-wu Kang Bao-lin Liu Tao Jing hou-fa Shen School of Materials Science and Engineering Key Laboratory for Advanced Materials Processing TechnologyTsinghua UniversityBeijing 100084China

Emerging technological advances are reshaping the casting sector in latest *** technology is evolving towards intelligent casting paradigm that involves automation,greenization and intelligentization,which attracts more and more attention from the academic and industry *** this paper,the main features of casting technology were briefly summarized and forecasted,and the recent developments of key technologies and the innovative efforts made in promoting intelligent casting process were ***,the technical visions of intelligent casting process were also put *** key technologies for intelligent casting process comprise 3D printing technologies,intelligent mold technologies and intelligent process control *** future,the intelligent mold that derived from mold with sensors,control devices and actuators will probably incorporate the Internet of Things,online inspection,embedded simulation,decision-making and control system,and other technologies to form intelligent cyber-physical casting system,which may pave the way to realize intelligent *** is promising that the intelligent casting process will eventually achieve the goal of real-time process optimization and full-scale control,with the defects,microstructure,performance,and service life of the fabricated castings can be accurately predicted and tailored.

关键词： intelligent casting 3D printing intelligent mold process control cyber-physical casting system embedded simulation

Parameter Estimation of a Valve-Controlled Cylinder System Model Based on Bench Test and Operating Data Fusion

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Chinese Journal of Mechanical Engineering 2024年第2期37卷 247-263页

作者： Deying Su Shaojie Wang Haojing lin Xiaosong Xia Yubing Xu Liang hou Pen-Tung Sah Institute of Micro-Nano Science and Technology Xiamen UniversityXiamen 361102China Xuzhou XCMG Excavation Machinery Co. LtdXuzhou 221000China

The accurate estimation of parameters is the premise for establishing a high-fidelity simulation model of a valve-controlled cylinder *** test data are easily obtained,but it is challenging to emulate actual loads in the research on parameter estimation of valve-controlled cylinder *** the actual load information contained in the operating data of the control valve,its acquisition remains *** paper proposes a method that fuses bench test and operating data for parameter estimation to address the aforementioned *** proposed method is based on Bayesian theory,and its core is a pool fusion of prior information from bench test and operating ***,a system model is established,and the parameters in the model are ***,the bench and operating data of the system are ***,the model parameters and weight coefficients are estimated using the data fusion ***,the estimated effects of the data fusion method,Bayesian method,and particle swarm optimisation(PSO)algorithm on system model parameters are *** research shows that the weight coefficient represents the contribution of different prior information to the parameter estimation *** effect of parameter estimation based on the data fusion method is better than that of the Bayesian method and the PSO *** load complexity leads to a decrease in model accuracy,highlighting the crucial role of the data fusion method in parameter estimation studies.

关键词： Valve-controlled cylinder system Parameter estimation The Bayesian theory Data fusion method Weight coefficients

Broadband absorption performance of 3D-printed polyetheretherketone-based electromagnetic wave-absorbing composites

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Chinese Journal of Aeronautics 2024年第8期37卷 547-558页

作者： lin BAI Nan CHANG Meiying ZHAO Chi hou Yi CAO Dichen LI School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China Chengdu Aircraft Design and Research Institute Chengdu 610091China Xi’an Key Laboratory of Advanced Structure Design and Application of Aircraft Northwestern Polytechnical UniversityXi’an 710072China State Key Laboratory for Manufacturing System Engineering Xi’an Jiaotong UniversityXi’an 710054China

The rapid development of additive manufacturing technology has offered a new avenue for designing and fabricating high wave-absorbing meta *** this study,the mechanical properties and broadband absorption performance of Poly-Ether-Ether-Ketone(PEEK)–based electromagnetic wave–absorbing composite materials was *** high-performance polymer PEEK was used as the matrix,and the materials with electromagnetic wave loss,such as reduced graphene oxide,Carbonyl Iron(CI),and Flake CI(FCI),were used as *** on the theory of impedance matching,a wave-absorbing structure with a gradual impedance gradient was designed and *** test results showed that at the 2.0–18.0 GHz frequency band,the coverage rate of the effective absorption bandwidth was up to 72.0%,the average optimal reflectivity was–18.09 dB,and the wide-angle absorption range was 0°–30°.The advantages of additive manufacturing technology in designing and fabricating wave-absorbing structures are presented,demonstrating that the technology is an effective method for creating broadband absorbing structures.

关键词： Absorption performance Additive manufacturing Electromagnetic absorption PEEK composite materials Gradual structure Broadband absorption