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Designing Proportional-Integral Consensus Protocols for Second-Order Multi-Agent Systems Using Delayed and Memorized State Information

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IEEE/CAA Journal of Automatica Sinica 2024年第4期11卷 878-892页

作者： honghai Wang Qing-Long Han the College of Information Science and Engineering State Key Laboratory of Synthetical Automation for Process IndustriesNortheastern UniversityShenyang 110819China the School of Science Computing and Engineering TechnologiesSwinburne University of TechnologyMelbourneVIC 3122Australia

This paper is concerned with consensus of a secondorder linear time-invariant multi-agent system in the situation that there exists a communication delay among the agents in the network.A proportional-integral consensus protocol is designed by using delayed and memorized state information.Under the proportional-integral consensus protocol,the consensus problem of the multi-agent system is transformed into the problem of asymptotic stability of the corresponding linear time-invariant time-delay system.Note that the location of the eigenvalues of the corresponding characteristic function of the linear time-invariant time-delay system not only determines the stability of the system,but also plays a critical role in the dynamic performance of the system.In this paper,based on recent results on the distribution of roots of quasi-polynomials,several necessary conditions for Hurwitz stability for a class of quasi-polynomials are first derived.Then allowable regions of consensus protocol parameters are estimated.Some necessary and sufficient conditions for determining effective protocol parameters are provided.The designed protocol can achieve consensus and improve the dynamic performance of the second-order multi-agent system.Moreover,the effects of delays on consensus of systems of harmonic oscillators/double integrators under proportional-integral consensus protocols are investigated.Furthermore,some results on proportional-integral consensus are derived for a class of high-order linear time-invariant multi-agent systems.

关键词： Consensus protocol Hurwitz stability multi-agent systems quasi-polynomials time delay

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Responses of nitrogen cycling and related microorganisms to brackish wetlands formed by evapotranspiration

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Pedosphere 2024年第1期34卷 252-266页

作者： Jiaohui FANG Tianshu LU Jian LIU Shangbin HE Xiufeng yang Huashan DOU honghai ZHANG School of Life Sciences Qufu Normal UniversityQufu 273100China Environment Research Institute Shandong UniversityQingdao 266237China Hulunbuir Academy of Inland Lakes in Northern Cold&Arid Areas Hulunbuir 021000China

Elevated evapotranspiration due to warmer air temperature could raise salinity and nutrient levels of some inland wetlands, potentially impacting nitrogen cycling. To characterize the impact of high evapotranspiration on soil microbial nitrogen cycling in inland wetlands, we compared freshwater and brackish marsh(or non-marsh) wetlands in terms of sediment ammonia-oxidizing rate(AOR), denitrifying rate(DR), and related microbial communities in a typical inland basin, the Hulun Lake basin, in China. Results showed that marsh ecosystems(ME) exhibited 31% higher AOR and 65% higher DR than non-marsh ecosystems(NE). For NE, freshwater non-marsh wetland exhibited 12% higher AOR than brackish non-marsh wetland. This was probably due to the inhibitory effects of high NH_4~+ and salinity levels on ammonia-oxidizing archaea in brackish non-marsh wetland. Conversely, DR in brackish non-marsh wetland was 23% higher than that in freshwater non-marsh wetland, with total organic carbon(TOC) significantly influencing this difference,suggesting that the higher DR in brackish non-marsh wetland was mainly due to its higher TOC level. For ME, due to the direct and indirect interference of salinity, brackish marsh wetland displayed 26% lower AOR and 19% lower DR than freshwater marsh wetland. Besides, brackish wetlands harbored distinct ammonia-oxidizing and denitrifying microbial communities compared to freshwater wetlands. The assembly of these communities was dominated by stochastic processes, while brackish wetlands exhibited more prominent deterministic processes than freshwater wetlands. Overall, high evapotranspiration altered activities and community characteristics of ammonia oxidizers and denitrifiers in inland brackish wetlands by enhancing salinity and nutrient levels,while emergent plants occurring in ME could mitigate the adverse effects of salt stress of inland brackish wetlands on nitrogen cycling.

关键词： ammonia-oxidizing archaea ammonia-oxidizing bacteria aquatic plants denitrifying bacteria nitrogen transformation inland wetlands

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Improved Proximal Policy Optimization Algorithm for Sequential Security-constrained Optimal Power Flow Based on Expert Knowledge and Safety Layer

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Journal of Modern Power Systems and Clean Energy 2024年第3期12卷 742-753页

作者： Yanbo Chen Qintao Du honghai Liu Liangcheng Cheng Muhammad Shahzad Younis State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources and School of Electrical & Electronic Engineering North China Electric Power University School of Engineering Xining University Key Laboratory of Smart Operation of New Energy Power System Ministry of Education Qinghai University China Electric Power Research Institute National University of Sciences and Technology

In recent years, reinforcement learning(RL) has emerged as a solution for model-free dynamic programming problem that cannot be effectively solved by traditional optimization methods. It has gradually been applied in the fields such as economic dispatch of power systems due to its strong selflearning and self-optimizing capabilities. However, existing economic scheduling methods based on RL ignore security risks that the agent may bring during exploration, which poses a risk of issuing instructions that threaten the safe operation of power system. Therefore, we propose an improved proximal policy optimization algorithm for sequential security-constrained optimal power flow(SCOPF) based on expert knowledge and safety layer to determine active power dispatch strategy, voltage optimization scheme of the units, and charging/discharging dispatch of energy storage systems. The expert experience is introduced to improve the ability to enforce constraints such as power balance in training process while guiding agent to effectively improve the utilization rate of renewable energy. Additionally, to avoid line overload, we add a safety layer at the end of the policy network by introducing transmission constraints to avoid dangerous actions and tackle sequential SCOPF problem. Simulation results on an improved IEEE 118-bus system verify the effectiveness of the proposed algorithm.

关键词： Renewable energy sources Safety Power systems Optimization Power grids Energy storage Training

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Synergistic precipitant powered self-assembly of papain for cross-linked enzyme crystals preparation

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Particuology 2024年第2期85卷 102-112页

作者： Qi Hao Pan Guo honghai Wang Min Su Chunli Li Yuqi Hu Weiyi Su School of Chemical Engineering and Technology Hebei University of TechnologyTianjin300130China National-Local Joint Engineering Laboratory for Energy Conservation of Chemical Process Integration and Resources Utilization Tianjin300130China

In this study,we prepared cross-linked enzyme crystals(CLECs)of papain to further broaden the application of the enzyme with high activity in extreme environments.Initially,papain crystals were successfully obtained based on the micro-batch,batch,and expanded batch crystallization experiments.Specifically,ammonium sulfate and polyethylene glycol 6000(PEG6000)were synergistically used as the precipitants,while L-cysteine was applied to enhance the activity of papain.Furthermore,the interaction between L-cysteine and papain was modeled by molecular docking technique.It was found that L-cysteine could form a hydrogen bond with aspartic acid residue(Asp)at site 158,and the electrostatic attraction with lysine residue(Lys)at site 156 was also quite obvious.Then the enzyme crystals were cross-linked by glutaraldehyde at optimized conditions.The papain CLECs were identified by various methods,and it was found that the thermal stability and enzymatic activity both increased compared to the raw enzyme.More importantly,it could be applied at more rigorous conditions,for example,pH of 4.

关键词： Papain Cross-linked enzyme crystals L-cysteine Molecular docking Crystallization

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Experimental Study on Performance of a Closed Wet Cooling Tower for Air Wet-Bulb Temperature near 0°C

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Journal of Thermal Science 2019年第5期28卷 1015-1023页

作者： ZHOU Yasu ZHANG Pan ZHAO Jingde yang honghai BAI Yufeng College of Environmental Science and Engineering Donghua University

Closed wet cooling towers(CWCTs) are used widely because of their better water quality and smaller water consumption. However, the operating parameters shown in the technical documents are only for rated conditions in summer, not for any other conditions, especially in low air wet-bulb temperature areas such as those near 0℃. In addition, CWCTs often fail to achieve the designed cooling effect at low air wet-bulb temperatures. A experiment set of CWCT was built, and the performance of the CWCT at low air wet-bulb temperature near 0℃ was investigated. The impact of the operating parameters(air flow rate, cooling water flow rate, and spray water flow rate) on the heat and mass transfer performance of the CWCT was measured and analyzed. The results show the cooling performance of the CWCT at an air wet-bulb temperature 0℃, 2℃, and 4℃ is about 47%–63% of the rated operating condition;the optimal operating parameters of these conditions for the CWCT are just the same as those of the rated operating condition in summer. According to the experimental results, some operating advices are given.

关键词： closed wet cooling tower performance of cooling tower low air wet-bulb temperature rated operating parameters evaluation index

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基于离散事件模拟模型的武汉市某三甲医院皮肤科普通门诊分时段预约诊疗号源分配研究

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医学与社会 2024年第4期37卷 104-109,115页

作者：刘红海王巍华中科技大学同济医学院医药卫生管理学院湖北武汉430030 华中科技大学同济医学院附属武汉中西医结合医院信息中心湖北武汉430022

目的:探索普通门诊分时段预约诊疗号源分配优化方式,为医院动态调整号源提供依据。方法:调取武汉市某三甲医院2019年3月份皮肤科普通门诊数据,采用离散事件模拟和预约号源容量分配情景假设进行仿真。结果:患者预约后平均等待时间为15.0... 详细信息

目的:探索普通门诊分时段预约诊疗号源分配优化方式,为医院动态调整号源提供依据。方法:调取武汉市某三甲医院2019年3月份皮肤科普通门诊数据,采用离散事件模拟和预约号源容量分配情景假设进行仿真。结果:患者预约后平均等待时间为15.08分钟,64%的线上预约患者未在预约时间段之前到达,患者预约后平均等待时间仿真结果与医院真实数据仅相差0.76分钟(P>0.05),情景模拟结果显示将患者候诊高峰上升趋势时间段号源均匀分配至其他时段,可减少普通门诊分时段预约患者39%的预约后平均等待时间。结论:调整线上、线下挂号途径号源投放量,削减候诊高峰,是减少医院门诊患者候诊时间的关键。通过离散事件模拟及号源分配应用,有助于促进医院门诊精细化管理。

关键词：预约诊疗分时段预约号源分配三甲医院普通门诊

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基于电池冷却用新型脉动热管性能的实验研究

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化工学报 2024年第6期75卷 2222-2232页

作者：李新泽张双星杨洪海杜文静山东大学能源与动力工程学院山东济南250061 东华大学环境科学与工程学院上海201600

提出一种电池冷却用C形脉动热管(pulsating heat pipe,PHP),具有较好的散热性和包裹特性。选择甲醇、丙酮、去离子水、乙醇和甲醇-丙酮混合物为PHP工质,实验研究了不同加热功率和充液率(filling rate,FR)工况下PHP的性能。结果表明,FR... 详细信息

提出一种电池冷却用C形脉动热管(pulsating heat pipe,PHP),具有较好的散热性和包裹特性。选择甲醇、丙酮、去离子水、乙醇和甲醇-丙酮混合物为PHP工质,实验研究了不同加热功率和充液率(filling rate,FR)工况下PHP的性能。结果表明,FR过高或过低均不利于C形PHP稳定运行,实际应用中需综合考虑热阻、传热极限等指标,选取合适的FR。实验研究范围内,C形PHP最佳FR在45%左右。综合考虑蒸发温度与热阻,甲醇-丙酮混合物C形PHP具备更好的性能,能够满足第二代Mirai电池冷却需求,可将其表面温度控制在84℃以下,允许的电池最大体积功率密度为6 kW/L。依据应用场合选择工质和布置方式后,PHP能保证受控对象的安全运行。相关结论为电池热控制系统设计提供了重要的参考和借鉴。

关键词：脉动热管传热热力学性质气液两相流相变

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黄河流域史前绿松石镶嵌制品初探

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考古与文物 2024年第5期 65-73页

作者：闫红贤陈洪海西北大学文化遗产学院

绿松石镶嵌制品是黄河流域史前时期颇具特色的一类器物,镶嵌技术可分为孔嵌和平面镶嵌两类。孔嵌法最早出现在海岱地区的大汶口文化晚期,龙山时代向晋南和陕北地区传播。平面镶嵌法最早出现在甘青地区的马家窑文化马家窑类型时期,大致... 详细信息

绿松石镶嵌制品是黄河流域史前时期颇具特色的一类器物,镶嵌技术可分为孔嵌和平面镶嵌两类。孔嵌法最早出现在海岱地区的大汶口文化晚期,龙山时代向晋南和陕北地区传播。平面镶嵌法最早出现在甘青地区的马家窑文化马家窑类型时期,大致在龙山时代向东传播到晋南和海岱地区。绿松石镶嵌技术的东西传播与互动,体现出史前时期“玉石之路”上文化交流与传播方式的多元化。

关键词：黄河流域史前时期绿松石镶嵌

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微振动模拟与主被动隔振一体化实验平台

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光学精密工程 2024年第5期32卷 694-703页

作者：秦超周洪海贺帅徐振邦朱赫中国科学院长春光学精密机械与物理研究所吉林长春130033 中国科学院大学北京100049 中国科学院空间光学系统在轨制造与集成系统重点实验室吉林长春130033

针对遥感卫星地面微振动实验的复杂要求,设计了一种同时具备微振动模拟与主被动隔振功能的一体化微振动实验平台,并对该平台的主、被动隔振性能以及微振动模拟效果分别进行了仿真分析和实验测试。其中,被动隔振由气浮支撑实现,主动隔振... 详细信息

针对遥感卫星地面微振动实验的复杂要求,设计了一种同时具备微振动模拟与主被动隔振功能的一体化微振动实验平台,并对该平台的主、被动隔振性能以及微振动模拟效果分别进行了仿真分析和实验测试。其中,被动隔振由气浮支撑实现,主动隔振采用主动阻尼方法抑制共振峰,微振动模拟采用基于线性系统频响函数的控制策略。实验结果表明,平台前六阶的模态频率分布均小于10 Hz,被动隔振系统能大幅抑制10~200 Hz频段内的地面微振动;主动隔振能够实现14 dB的隔振系统共振峰衰减效果。微振动模拟功能能够有效产生接近星上的单频和多频真实扰动线谱,在特定频谱的扰动模拟实验中,幅值最大误差为5.9%,在误差允许范围内。该多功能一体化实验平台的各项功能均能满足地面模拟实验需求。

关键词：微振动实验有限元分析主动隔振被动隔振微振动模拟

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基于MVO算法与改进目标函数的电力系统负荷频率控制

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电力系统保护与控制 2024年第6期52卷 1-14页

作者：李谟发张志文胡斯佳练红海湖南大学电气与信息工程学院湖南长沙410082 湖南电气职业技术学院风能工程学院湖南湘潭411101

针对风电并网时的随机波动功率、负荷频率控制(load frequency control, LFC)系统参数变化所引起的电力系统频率稳定问题,提出了一种基于智能优化算法与改进目标函数的互联电网LFC系统最优PID控制器设计方法。首先,分析了基于PID控制的... 详细信息

针对风电并网时的随机波动功率、负荷频率控制(load frequency control, LFC)系统参数变化所引起的电力系统频率稳定问题,提出了一种基于智能优化算法与改进目标函数的互联电网LFC系统最优PID控制器设计方法。首先,分析了基于PID控制的含风电互联电力系统LFC闭环模型。其次,在时间乘误差绝对值积分(integral of time multiplied absolute error, ITAE)性能指标的目标函数中考虑了区域控制器的输出信号偏差,对优化目标函数进行改进。采用性能优良的多元宇宙优化(multi-verse optimizer, MVO)算法先计算后验证的思路,寻优获得最优PID控制器参数。最后,以两区域4机组互联电力LFC系统为例,仿真验证了基于MVO算法结合改进目标函数所获得的PID控制器,比基于MVO算法所获得的PID控制器,对阶跃负荷扰动、随机负荷扰动、风电功率偏差扰动以及系统的参数变化,具有相对较好的鲁棒性能。并且,对控制器参数也具有相对较好的非脆弱性指标。

关键词：多元宇宙优化算法风电负荷频率控制目标函数互联电力系统渗透率

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