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Research on probabilistic safety assessment (PSA) method of safety class distributed control system (DCS) in nuclear power plant based on fuzzy Markov process

Research on probabilistic safety assessment (PSA) method of ...

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2020 International Conference on Nuclear Engineering, ICONE 2020, collocated with the ASME 2020 Power Conference

作者： Tian, Xufeng Hao, Yan Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China HuaFu avenue 299# section 3 Chengdu city610213 China

ISBN: (纸本)9780791883778

Safety class DCS(Distributed Control system) in nuclear power plant is characterized by multi-state interaction, complex function and unknown fault mechanism, which limits the use of tradition PSA(Probabilistic Safety Assessment) method such as event tree and fault tree. An improved dynamic probabilistic security simulation method is proposed based on fuzzy Markov process to quantitative evaluation the risk of Safety class DCS in nuclear power plant, which resolved the failure uncertainty problem without in-depth understanding of failure mechanism. Firstly, the fuzzy fault tree reliability evaluation model is established based on fuzzy theory and FTA(Fault Tree Analysis), which describes the probability and degree of failure with fuzzy number. Then, the fuzzy fault tree is transformed into fuzzy Markov chain, this model is described mathematically, and the reliability indexes are simulated and analyzed with Monte Carlo simulation method, the change of system safety performance in long-term operation is obtained. Finally, the scientificity and effectiveness is verified by the example of redundant analog output module of safety class DCS in nuclear plant. Copyright © 2020 ASME

关键词： Nuclear power plants

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The dynamic compressive properties of magnetorheological plastomers: enhanced magnetic-induced stresses by non-magnetic particles

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Journal of Materials science & technology 2022年第7期102卷 195-203页

作者： Haoming Pang Zhenbang Xu Longjiang Shen Jun Li Junshuo Zhang Zhiyuan Li Shouhu Xuan Xinglong Gong CAS Key Laboratory of Mechanical Behavior and Design of Materials Department of Modern MechanicsCAS Center for Excellence in Complex System MechanicsUniversity of Science and Technology of China(USTC)Hefei 230027China Anhui Weiwei Rubber Parts Group Co.Ltd Tongcheng 231400China CAS Key Laboratory of On-orbit Manufacturing and Integration for Space Optics System Changchun Institute of OpticsFine Mechanics and PhysicsChinese Academy of SciencesChangchun 130033China Hunan Bogie Engineering Research Center Zhuzhou 412000China

In this research, a series of hollow glass powder(HGP) reinforced magnetorheological plastomers(MRPs)were prepared to improve the impact resistance of the materials, and the dynamic compressive properties of MRPs under high strain rate were investigated by using a split Hopkinson pressure bar(SHPB)system equipped with a customized magnetic device. Experimental results showed the HGPs greatly enhanced the yield stresses of the MRPs. Especially, for MRPs with 9 vol.% carbonyl iron powders(CIPs), the magnetic-induced yield stress increased from 7.3 MPa to 17.1 MPa(134% increased) by adding 18 vol.%HGPs. The particle structures in MRPs were further simulated and the corresponding intergranular stress was calculated to study the enhancement effect of HGPs. The simulated results showed that more compact structures were formed with the excluded volume caused by secondary HGPs, so the yield stresses of the MRPs increased under a magnetic field. However, when the mass ratio of HGP to CIP was larger than 0.67, HGPs would hinder the formation of chain-like structures and reduce the magneto-mechanical properties. As a result, the replacing of CIPs by HGPs was proven to be an excellent strategy to improve the dynamic properties of MRPs.

关键词： Particle-reinforced composites Stress/strain curves Microstructures Impact behavior Mechanical properties

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design of an Online Operational Task Reliability Analysis system in Nuclear Power Plant

Design of an Online Operational Task Reliability Analysis Sy...

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system Reliability and Safety Engineering (SRSE), International Conference on

作者： Wei Li Ming Yang Zhengxi He Zhao Gao Yan Xiong Zhongyue Zhang Dehang Jiang Jipu Wang Fundamental Science on Nuclear Safety and Simulation Technology Laboratory College of Nuclear Science and Technology Harbin Engineering University Harbin China Nuclear Reactor System Design Technology Key Laboratory China Nuclear Power Research and Design Institute Chendu China Institute for Advanced Study in Nuclear Energy & Safety College of Physics and Optoelectronic Engineering Shenzhen University Shenzhen China

Human factors play an important role in human- computer interaction systems such as nuclear power plants (NPPs). Especially for the human-computer interaction process in unknown scenarios, incorrect personnel actions will affect the operation of equipment and systems, and finally the achievement of safety goals of NPPs. This paper presents a design of an online operational task reliability analysis (OOTRA) system which provides early warnings to operations in a timely manner by monitoring the states of plant systems and equipment, and operator actions. For any wrong action of operators, the OOTRA system can online evaluate the impact of the wrong action on the operational task and the goals of NPPs.

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Communication-efficient and Differentially-private Distributed Nash Equilibrium Seeking with Linear Convergence

arXiv

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arXiv 2024年

作者： Chen, Xiaomeng Huo, Wei Ding, Kemi Dey, Subhrakanti Shi, Ling The Department of Electronic and Computer Engineering Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong The School of System Design and Intelligent Manufacturing Southern University of Science and Technology Shenzhen518055 China The Department of Electrical Engineering Uppsala University Uppsala751 03 Sweden

The distributed computation of a Nash equilibrium (NE) for non-cooperative games is gaining increased attention recently. Due to the nature of distributed systems, privacy and communication efficiency are two critical concerns. Traditional approaches often address these critical concerns in isolation. This work introduces a unified framework, named CDP-NES, designed to improve communication efficiency in the privacy-preserving NE seeking algorithm for distributed non-cooperative games over directed graphs. Leveraging both general compression operators and the noise adding mechanism, CDP-NES perturbs local states with Laplacian noise and applies difference compression prior to their exchange among neighbors. We prove that CDP-NES not only achieves linear convergence to a neighborhood of the NE in games with restricted monotone mappings but also guarantees ϵdifferential privacy, addressing privacy and communication efficiency simultaneously. Finally, simulations are provided to illustrate the effectiveness of the proposed method. © 2024, CC BY.

关键词： Directed graphs

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Multi-Objective Optimization Problem With Hardly Dominated Boundaries: Benchmark, Analysis, and Indicator-Based Algorithm

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IEEE Transactions on Evolutionary Computation 2024年 1-1页

作者： Wang, Zhenkun Lin, Kangnian Li, Genghui Gao, Weifeng School of System Design and Intelligent Manufacturing Southern University of Science and Technology Shenzhen P.R. China College of Computer Science and Software Engineering Shenzhen University Shenzhen P.R. China School of Mathematics and Statistics Xidian University Xi’an China

The hardly dominated boundary (HDB) is commonly observed in multi-objective optimization problems (HDBMOPs). However, there are only a few benchmark problems related to HDB-MOPs in the evolutionary computation community, which is insufficient to validate the performance of multi-objective evolutionary algorithms (MOEAs). In this paper, we first introduce a new set of HDB-MOPs characterized by various shapes of Pareto fronts and scalable HDB sizes. We then systematically analyze the capabilities of several representative existing MOEAs in handling HDB-MOPs and reveal their strengths and weaknesses in solving this type of problem. Finally, based on this insightful analysis, we propose an indicator-based MOEA with an adaptive reference point to effectively address HDB-MOPs. The source codes of the proposed benchmark problems and the IMOEAARP algorithm are available from https://***/CIAMGroup/ EvolutionaryAlgorithm Codes/tree/main/IMOEA-ARP. IEEE

关键词： Evolutionary algorithms

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Effect of yttrium and calcium additions on electrochemical behaviors and discharge performance of AZ80 anodes for Mg-air battery

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Transactions of Nonferrous Metals Society of China 2022年第8期32卷 2510-2526页

作者： Yu-wen-xi ZHANG Lu HAN Lin-bao REN Ling-ling FAN Yang-yang GUO Ming-yang ZHOU Gao-feng QUAN Key Laboratory of Advanced Technologies of Materials(Ministry of Education) School of Materials Science and EngineeringSouthwest Jiaotong UniversityChengdu 610031China Center for Advancing Materials Performance from the Nanoscale State Key Laboratory for Mechanical Behavior of MaterialsXi’an Jiaotong UniversityXi’an 710049China Xi’an Rare Metal Materials Institute Co. Ltd.Xi’an 710049China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of ChinaChengdu 610213China

The effects of yttrium(Y)and yttrium+calcium(Y+Ca)additions on the electrochemical properties and discharge performance of the as-extruded Mg−8Al−0.5Zn−0.2Mn(AZ80)anodes for Mg−air batteries were *** results show that the addition of 0.2 wt.%Y increased the corrosion resistance and discharge activity of AZ80 *** was attributed to the fine and sphericalβ-Mg_17)Al_(12) phases dispersing evenly in AZ80+0.2Y alloy,which suppressed the localized corrosion and severe“chunk effect”,and facilitated the rapid activation ofα-*** addition of 0.2 wt.%Y and 0.15 wt.%Ca generated grain refinement and a reduction of theβ-Mg_17)Al_(12) phase,resulting in a further enhancement in discharge ***,the incorporation of Ca in Mg_17)Al_(12) and Al_(2)Y compounds compromised the corrosion resistance and anodic efficiency of AZ80+0.2Y+0.15Ca ***,AZ80+0.2Y anode exhibited excellent overall discharge performance,with the peak discharge capacity and anodic efficiency of 1525 mA·h·g^(−1) and 67%at 80 mA/cm^(2),13%and 14%higher than those of AZ80 anode,respectively.

关键词： Mg-air battery Mg-Al-Zn anode discharge performance electrochemical behavior

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Optimizing Information Freshness in Mobile Networks with Age-Threshold ALOHA

Optimizing Information Freshness in Mobile Networks with Age...

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IEEE International Symposium on Information Theory

作者： Fangming Zhao Nikolaos Pappas Chuan Ma Xinghua Sun Tony Q. S. Quek Howard H. Yang ZJU-UIUC Institute of Zhejiang University Haining China Department of Computer and Information Science Linköping University Linköping Sweden School of Computer Science Chongqing University Chongqing China School of Electronics and Communication Engineering Sun Yat-sen University Shenzhen China Information System and Technology Design Pillar Singapore University of Technology and Design Singapore

ISBN: (数字)9798350382846

ISBN: (纸本)9798350382853

We optimize the Age of Information (AoI) in random access networks using the age-threshold slotted ALOHA (TSA) protocol. The network comprises multiple source-destination pairs, where each source sends a sequence of status update packets to its destination over a shared spectrum. The TSA protocol stipulates that a source node must remain silent until its AoI reaches a predefined threshold, after which the node accesses the radio channel with a certain probability. We derive analytical expressions for the transmission success probability and time-average AoI using stochastic geometry tools. Subsequently, we obtain closed-form expressions for the optimal update rate and age threshold that minimize the time-average AoI. In addition, we establish a scaling law for the time-average AoI in random access networks, revealing that the optimal time-average AoI increases linearly with the deployment density. Notably, the growth rate under TSA is half of that under conventional slotted ALOHA.

关键词： Geometry Protocols Closed-form solutions Information age Information theory

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Observer-Based Fault Tolerant Formation Control of Multi-Agent systems via Adaptive Dynamic Programming

Observer-Based Fault Tolerant Formation Control of Multi-Age...

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Data Driven Control and Learning systems (DDCLS)

作者： Yongwei Zhang Bo Zhao Derong Liu College of Mathematics and Informatics South China Agricultural University Guangzhou China School of Systems Science Beijing Normal University Beijing China School of System Design and Intelligent Manufacturing Southern University of Science and Technology Shenzhen China

ISBN: (数字)9798350361674

ISBN: (纸本)9798350361681

This paper develops a fault tolerant formation control scheme for multi-agent systems (MASs) by using adaptive dynamic programming. In MASs, there exist one leader and multiple followers, where the leader is a generated ideal trajectory and the followers catch up with the leader using appropriate designed control inputs based on their own and neighbors' information. To obtain accurate fault information, a fault observer is established for each follower. Subsequently, a discounted cost function, which includes the estimated fault, the formation error, and the control laws, is developed for each following agent. In order to solve the coupled Hamilton-Jacobi-Bellman equation of each follower, a critic-only structure is built to obtain the approximate fault tolerant formation control law. Furthermore, it is proved that the uniform ultimate boundedness of the formation error of each following agent is guaranteed under the developed observer-based fault tolerant formation control law. It means that all following agents are able to maintain a specified formation and catch up with the leader. Finally, a simulation example is employed to validate the effectiveness of the present control approach.

关键词： Fault tolerance Simulation Fault tolerant systems Observers Control systems Formation control Mathematical models

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design of Pelton Turbine Test Stand in Plateau Environment 4

Design of Pelton Turbine Test Stand in Plateau Environment

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4th IAHR Asian Working Group Symposium on Hydraulic Machinery and systems

作者： Cai, Jinhan Zhou, Xuejun Luo, Hongying Wang, Zhengwei Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin300384 China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of Technology China College of Mechanical Engineering Tianjin Sino-German University of Applied Science No. 2 Yashen Road Tianjin China College of Hydraulic and Civil Engineering Tibet Agricultural and Animal Husbandry University China Department of Energy and Power Engineering Tsinghua University China

In recent years, with the continuous development of China's hydropower projects, Pelton turbines are gradually being valued, and the focus of development has shifted from plain areas to plateau areas. Environmental impacts such as high altitude, water temperature, and high sediment content in the plateau area have caused serious interference to equipment that originally worked in a stable environment, for example, the failure of the cooperation between the parts of the turbine and the mutual seizure, the increased wear of the nozzle needle, the decrease of the flow rate and the water outlet speed of the nozzle, and the decrease of the air pressure in the plateau environment lead to the change of the flow state of the nozzle. In view of the above problems, this paper puts forward the design scheme of impulse turbine test-bed, using the method of changing specific speed to determine the basic parameters of impulse turbine unit, so as to eliminate the influence of plateau environment on the normal operation of turbine, obtain the efficiency condition of model experiment under low ambient pressure, and improve the operation efficiency and reliability of turbine unit. © 2024 Institute of Physics Publishing. All rights reserved.

关键词： Nozzles

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Positioning Control for Voice Coil Motor Using Unbalanced Multilevel Inverter Topology

Positioning Control for Voice Coil Motor Using Unbalanced Mu...

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International Conference on Mechatronics (ICM)

作者： Gaku Takei Hidemine Obara Ryo Haneda Takahiro Nozaki Graduate School of Science and Technology Keio University Yokohama Japan Department of Physics Electrical and Computer Engineering Yokohama National University Yokohama Japan Department of System Design Engineering Keio University Yokohama Japan

ISBN: (数字)9798331533892

ISBN: (纸本)9798331533908

This article proposes a new multi-level inverter (MLI) based on flying capacitor inverter (FCI), with focused on high-precision positioning control for a voice coil motor (VCM). Multi-level inverters (MLIs) have the characteristic that increasing the number of output voltage levels reduces the output voltage error. However, as the number of levels increases, the number of circuit elements increases, and the circuit becomes more complex. In addition, the output voltage amplitude for each level is constant in conventional inverters. As a result, such as high-precision positioning control of VCM, designing an appropriate inverter for a reference wave that contains a large amount of low-voltage components increases the number of circuit elements. Therefore, this paper proposes a MLI with two unbalanced dc-input voltages, referred to as unbalanced MLIs (UMLIs) hereinafter. This topology uses two different dc-input voltages, and it is possible to reduce the output voltage level in extremely low-voltage range compared to other voltage levels. Simulation results when the high-precision positioning control of the VCM confirm that the proposed UMLIs improves the control performance compared to the conventional FCIs with equal number of output voltage levels and uniform level widths.

关键词： Coils Low voltage Simulation Switches Multilevel inverters Motors Topology Sensors Voltage control Motion control

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