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Research and analysis of Brillouin distributed sensing system based on quasi-single-mode few-mode fiber

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Optoelectronics Letters 2024年第1期20卷 7-11页

作者： LI Yongqian LIU Zijuan ZHANG Lixin TIAN Min FAN Haijun Department of Electronic and Communication Engineering North China Electric Power UniversityBaoding 071003China hebei key laboratory of power internet of things technology North China Electric Power UniversityBaoding 071003China Baoding key laboratory of Optical Fiber Sensing and Optical Communication technology North China Electric Power UniversityBaoding 071003China

A distributed fiber sensor was fabricated by splicing two single-mode fibers(SMFs)using the few-mode fiber(FMF)technique.A Brillouin optical time domain analysis(BOTDA)system was developed to measure the sensor’s temperature and bending ***-mode and four-mode step FMFs were combined to splice the few-mode *** results indicate that the temperature response coefficients of the few-mode segment are only slightly higher than those of the connected single-mode segment,measuring at 1.13 MHz/℃and 1.12 MHz/℃,*** minimum bending radius for the sensor is 0.9 cm,and the four-mode bending response curve is superior to that of the two-mode one,proving that 4-SI-FMF offers better bending sensitivity.

关键词： fiber technique mode

An efficient physics-guided Bayesian framework for predicting ground settlement profile during excavations in clay

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第4期16卷 1411-1424页

作者： Cong Tang Shuyu He Wanhuan Zhou State key laboratory of internet of things for Smart City and Department of Civil and Environmental Engineering University of MacaoChina

Recently,the application of Bayesian updating to predict excavation-induced deformation has proven successful and improved prediction accuracy ***,updating the ground settlement profile,which is crucial for determining potential damage to nearby infrastructures,has received limited *** address this,this paper proposes a physics-guided simplified model combined with a Bayesian updating framework to accurately predict the ground settlement *** advantage of this model is that it eliminates the need for complex finite element modeling and makes the updating framework ***,the model is physically interpretable,which can provide valuable references for construction *** effectiveness of the proposed method is demonstrated through two field case studies,showing that it can yield satisfactory predictions for the settlement profile.

关键词： Bayesian updating Excavations Ground settlement profile Simplified model Uncertainty

Debris flow runout behaviors considering the influences of densely populated buildings

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Journal of Mountain Science 2024年第8期21卷 2696-2712页

作者： ZHANG Shuai FANG Zhe DAI Cong WANG Shuairong PENG Jingyu ZHOU Yiling SHEN Ping MOE key laboratory of Soft Soils and Geoenvironmental Engineering Zhejiang UniversityHangzhou 310058China State key laboratory of internet of things for Smart City and Department of Ocean Science and technology University of MacaoMacao SAR 999078China

Debris flows pose serious risks to communities in mountainous areas,often resulting in large losses of human life and *** impeding presence of urban buildings often affects the runout behavior and deposition of debris *** the impact of different building densities and sizes on debris flow dynamics has yet to be quantified to guide urban planning in debris flow risk *** study focused on a debris flow that occurred in Zhouqu County,Gansu Province,China on August 7th,2010,which was catastrophic and destroyed many *** FLO-2D software was used to simulate this debris flow in two scenarios,*** presence and the absence of buildings,to obtain debris-flow intensity *** developed model was then used to further analyze the influence of large buildings and narrow channels within the urban *** simulation results show that considering the presence of buildings in the simulation is essential for accurate assessment of debris flow intensity and deposition *** layout of buildings in the upstream urban area,such as large buildings or parallel buildings which form narrow channels,can affect the flow velocity and depth of debris flow heading towards downstream *** mitigate damage to downstream buildings,the relative spacing(d/a)between upstream and downstream buildings should not exceed a value of two and should ideally be even *** findings provide valuable insights for improving the resistance of mountainous cities to urban debris flows.

关键词： Debris flow Risk Building blockage effect Zhouqu Urban layout

Stochastic Unit Commitment with High-Penetration Offshore Wind power Generation in Typhoon Scenarios

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Journal of Modern power Systems and Clean Energy 2024年第2期12卷 535-546页

作者： Yanqi Liu Dundun Liu Hongcai Zhang State key laboratory of internet of things for Smart City and Department of Electrical and Computer Engineering University of MacaoMacao 999078China University of Macao Zhuhai UM Science and technology Research Institute ZhuhaiChina

To tackle the energy crisis and climate change,wind farms are being heavily invested in across the *** China's coastal areas,there are abundant wind resources and numerous offshore wind farms are being *** secure operation of these wind farms may suffer from typhoons,and researchers have studied power system operation and resilience enhancement in typhoon ***,the intricate movement of a typhoon makes it challenging to evaluate its spatial-temporal *** published papers only consider predefined typhoon trajectories neglecting *** address this challenge,this study proposes a stochastic unit commitment model that incorporates high-penetration offshore wind power generation in typhoon *** adopts a data-driven method to describe the uncertainties of typhoon trajectories and considers the realistic anti-typhoon mode in offshore wind farms.A two-stage stochastic unit commitment model is designed to enhance power system resilience in typhoon *** formulate the model into a mixed-integer linear programming problem and then solve it based on the computationally-efficient progressive hedging algorithm(PHA).Finally,numerical experiments validate the effectiveness of the proposed method.

关键词： Unit commitment two-stage stochastic programming offshore wind farm typhoon

Exploiting demand-side heterogeneous flexible resources in risk management of power system frequency

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Science China(Technological Sciences) 2024年第5期67卷 1612-1627页

作者： YAO Yu SONG YongHua YE ChengJin DING Yi ZHAO YuMing College of Electrical Engineering Zhejiang UniversityHangzhou310027China State key laboratory of internet of things for Smart City University of MacaoMacao SAR519000China Shenzhen power Supply Bureau Co. Ltd.Shenzhen518051China

More demand-side flexible resources(DFRs)are participating in the frequency regulation of renewable power systems,whose heterogeneous characteristics have a significant impact on the system frequency ***,selecting suitable DFRs poses a formidable challenge for independent system operators(ISO).In this paper,a reserve allocation methodology for heterogeneous DFRs is proposed to manage the risk of power system ***,a performance curve is developed to describe the cost,capacity,and response speed of ***,a clustering method for multiple distributed DFRs is conducted to calculate the aggregated performance curves and uncertainty ***,the frequency security criterion considering DFRs’performance is constructed,whose linearity makes it can be easily coupled into the system scheduling model and ***,a risk management model for DFRs considering frequency-chance-constraint is proposed to make a trade-off between cost and frequency ***,the model is transformed into mixed integer second-order cone programming(MISOCP)and solved by the commercial *** proposed model is validated by the IEEE 30 and IEEE 118 bus systems.

关键词： demand-side heterogenous flexible resources risk management of power system frequency performance curve aggregation method mixed integer second-order cone programming

A Least-squares-based Iterative Method with Better Convergence for PF/OPF in Integrated Transmission and Distribution Networks

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CSEE Journal of power and Energy Systems 2024年第3期10卷 953-962页

作者： Kunjie Tang Shufeng Dong Yonghua Song College of Electrical Engineering Zhejiang UniversityHangzhou 310027China State key laboratory of internet of things for Smart City and Department of Electrical and Computer Engineering University of MacaoMacao SARChina IEEE

The limitations of the conventional master-slavesplitting(MSS)method,which is commonly applied to power flow and optimal power flow in integrated transmission and distribution(I-T&D)networks,are first *** that the MSS method suffers from a slow convergence rate or even divergence under some circumstances,a least-squares-based iterative(LSI)method is *** with the MSS method,the LSI method modifies the iterative variables in each iteration by solving a least-squares problem with the information in previous iterations.A practical implementation and a parameter tuning strategy for the LSI method are ***,a LSI-PF method is proposed to solve I-T&D power flow and a LSIheterogeneous decomposition(LSI-HGD)method is proposed to solve optimal power *** experiments demonstrate that the proposed LSI-PF and LSI-HGD methods can achieve the same accuracy as the benchmark ***,these LSI methods,with appropriate settings,significantly enhance the convergence and efficiency of conventional ***,in some cases,where conventional methods diverge,these LSI methods can still converge.

关键词： Fixed-point theory integrated transmission and distribution networks least-squares-based iterative method master-slave-splitting method optimal power flow power flow

Energy Harvesting in the Wake of An Inverted C-Shaped Bluff Body

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China Ocean Engineering 2024年第1期38卷 68-80页

作者： WANG Jun-lei LI Shen-fang Md.Mahbub ALAM ZHU Hong-jun HU Guo-biao School of Mechanical and power Engineering Zhengzhou UniversityZhengzhou 450000China Center for Turbulence Control Harbin Institute of Technology(Shenzhen)Shenzhen 518055China State key laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum UniversityChengdu 610500China internet of things Thrust The Hong Kong University of Science and Technology(Guangzhou)Guangzhou 511400China

This paper proposes a novel wake-induced vibration(WIV)-based energy harvesting system consisting of two bluff *** inverted C-shaped bluff body is stationary installed at the upstream position to generate an interference wake street,and a cylinder bluff body equipped with a transducer is elastically suspended at the downstream position to harness WIV *** hydrodynamics and energy harvesting(EH)performance of the proposed system are investigated via experimental *** reduced velocity(U*)ranging from 2 to 14(the corresponding Reynolds number ranging from 15100 to 106200)is considered in the present *** is found that the wake generated by the inverted C-shaped bluff body significantly affects the EH *** the opening angle(α)of the C-shaped bluff body increases the vibration amplitude of the downstream cylinder,thereby increasing the harvested *** the spacing(L)between two bluff bodies is two times the cylinder diameter(D),the wake-induced vibration(WIV)mode is observed,while the combined WIV and wake galloping(WG)mode occurs whenαis 150°,and L equals 3D or *** average drag coefficient becomes negative when L is 2D,3D,or *** carefully configuring a C-shaped bluff body,the wake generated by it can bring an augmenting effect on the vibration of the downstream EH *** example,the RMS power output of the proposed EH system reaches a maximum of 0.31 W at U*=8 and L=4D,which is 300%greater than that of its traditional ***,after a number of case stud-ies,it is identified that the proposed EH system can achieve the best performance whenαis 150°and L=2D.

关键词： wake-induced vibration vortex-induced vibration galloping energy harvesting bluff body

Integrated Clustering and Routing Design and Triangle Path Optimization for UAV-Assisted Wireless Sensor Networks

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China Communications 2024年第4期21卷 178-192页

作者： Shao Liwei Qian Liping Wu Mengru Wu Yuan College of Information Engineering Zhejiang University of TechnologyHangzhou 310014China State key laboratory of internet of things for Smart City University of MacaoMacaoChina Department of Computer and Information Science University of MacaoMacaoChina

With the development of the internet of things(IoT),it requires better performance from wireless sensor networks(WSNs),such as larger coverage,longer lifetime,and lower ***,a large amount of data generated from monitoring and long-distance transmission places a heavy burden on sensor nodes with the limited battery *** this,we investigate an unmanned aerial vehicles assisted mobile wireless sensor network(UAV-assisted WSN)to prolong the network lifetime in this ***,we use UAVs to assist the WSN in collecting *** the current UAV-assisted WSN,the clustering and routing schemes are determined ***,such a separate consideration might not maximize the lifetime of the whole WSN due to the mutual coupling of clustering and *** efficiently prolong the lifetime of the WSN,we propose an integrated clustering and routing scheme that jointly optimizes the clustering and routing *** the whole network space,it is intractable to efficiently obtain the optimal integrated clustering and routing ***,we propose the Monte-Las search strategy based on Monte Carlo and Las Vegas ideas,which can generate the chain matrix to guide the algorithm to find the solution *** point-to-point collection leads to long collection paths,so a triangle optimization strategy is then proposed that finds a compromise path to shorten the collection path based on the geometric distribution and energy of sensor *** avoid the coverage hole caused by the death of sensor nodes,the deployment of mobile sensor nodes and the preventive mechanism design are *** emergency data transmission mechanism is further proposed to reduce the latency of collecting the latency-sensitive data due to the absence of *** with the existing schemes,the proposed scheme can prolong the lifetime of the UAVassisted WSN at least by 360%,and shorten the collection path of UAVs by 56.24%.

关键词： Monte-Las search strategy triangle path optimization unmanned aerial vehicles wireless sensor networks

Constraint Learning-based Optimal power Dispatch for Active Distribution Networks with Extremely Imbalanced Data

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CSEE Journal of power and Energy Systems 2024年第1期10卷 51-65页

作者： Yonghua Song Ge Chen Hongcai Zhang State key laboratory of internet of things for Smart City and Department of Electrical and Computer Engineering University of MacaoMacao 999078China School of Electrical and Computer Engineering Purdue UniversityWest LafayetteIN 47907 USA

Transition towards carbon-neutral power systems has necessitated optimization of power dispatch in active distribution networks(ADNs)to facilitate integration of distributed renewable *** to unavailability of network topology and line impedance in many distribution networks,physical model-based methods may not be applicable to their *** tackle this challenge,some studies have proposed constraint learning,which replicates physical models by training a neural network to evaluate feasibility of a decision(i.e.,whether a decision satisfies all critical constraints or not).To ensure accuracy of this trained neural network,training set should contain sufficient feasible and infeasible ***,since ADNs are mostly operated in a normal status,only very few historical samples are ***,the historical dataset is highly imbalanced,which poses a significant obstacle to neural network *** address this issue,we propose an enhanced constraint learning ***,it leverages constraint learning to train a neural network as surrogate of ADN's ***,it introduces Synthetic Minority Oversampling Technique to generate infeasible samples to mitigate imbalance of historical *** incorporating historical and synthetic samples into the training set,we can significantly improve accuracy of neural ***,we establish a trust region to constrain and thereafter enhance reliability of the *** confirm the benefits of the proposed method in achieving desirable optimality and feasibility while maintaining low computational complexity.

关键词： Deep learning demand response distribution networks imbalanced data optimal power flow