A new kind of optimal fuzzy PID controller is proposed, which contains two parts. One is an on line fuzzy inference system, and the other is a conventional PID controller. In the fuzzy inference system, three adjustab...A new kind of optimal fuzzy PID controller is proposed, which contains two parts. One is an on line fuzzy inference system, and the other is a conventional PID controller. In the fuzzy inference system, three adjustable factors x p, x i , and x d are introduced. Their functions are to further modify and optimize the result of the fuzzy inference so as to make the controller have the optimal control effect on a given object. The optimal values of these adjustable factors are determined based on the ITAE criterion and the Nelder and Mead′s flexible polyhedron search algorithm. This optimal fuzzy PID controller has been used to control the executive motor of the intelligent artificial leg designed by the authors. The result of computer simulation indicates that this controller is very effective and can be widely used to control different kinds of objects and processes.展开更多
The photovoltaic(PV)output process is inherently complex,often disrupted by a multitude of meteoro-logical factors,while conventional detection methods at PV power stations prove inadequate,compromising prediction acc...The photovoltaic(PV)output process is inherently complex,often disrupted by a multitude of meteoro-logical factors,while conventional detection methods at PV power stations prove inadequate,compromising prediction accuracy.To address this challenge,this paper introduces a power prediction method that leverages modal switching(MS),weight factor adjustment(WFA),and parallel long short-term memory(PALSTM).Initially,historical PV power station data is categorized into distinct modes based on global horizontal irradiance and converted solar angles.Correlation analysis is then employed to evaluate the impact of various meteorological factors on PV power,selecting those with strong correlations for each specific mode.Subsequently,the weights of meteorological parameters are optimized and adjusted,and a PALSTM neural network is constructed,with its parallel modal parameters refined through training.Depending on the prediction time and input data mode characteristics,the appropriate mode channel is selected to forecast PV power station generation.Ultimately,the feasibility of this method is validated through an illustrative analysis of measured data from an Australian PV power station.Comparative test results underscore the method’s advantages,particularly in scenarios where existing detection methods are lacking and meteorological factors frequently fluctuate,demonstrating its superior prediction accuracy and stability.展开更多
The depth adjustment factor for bending strength stated in Eurocode 5(EC5)is only applicable to timbers having a characteristic density below 700 kg/m3.However,most Malaysian timbers are hardwood,some with a charac...The depth adjustment factor for bending strength stated in Eurocode 5(EC5)is only applicable to timbers having a characteristic density below 700 kg/m3.However,most Malaysian timbers are hardwood,some with a characteristic density reaching above 700 kg/m3.Therefore,the objective of this study was to examine whether the depth adjustment factor stipulated in EC5 is valid for Malaysian hardwood timbers.Six timber species were selected for this study,namely Kapur(Dryobalanops C.F.Gaertn.),Kempas(Koompassia Maingay ex Benth.),Keruing(Dipterocarpus C.F.Gaertn.),Light red meranti(Shorea Roxb.ex C.F.Gaertn.),Geronggang(Cratoxylum Blume)and Balau(Shorea Roxb.ex C.F.Gaertn.).The determination of bending strength and characteristic density was conducted according to BS EN 408:2010 and BS EN 384:2016,respectively.A graph for mean bending strength vs.(150/h)was plotted for each timber species.The power function was selected to analyze the relationship between the two variables.The power of the regression equations varied depending on the characteristic density of the timber species.For species with a characteristic density below 700 kg/m3,such as Kapur,Keruing,and Light red meranti,the power was between 0.16 to 0.17.In contrast,for species having a characteristic density above 700 kg/m3,namely Kempas and Balau,the power was higher at 0.23 and 0.24,respectively.Geronggang was an exception to this pattern.These values are close to the depth adjustment factor given in EC5,which is 0.2.Based on the results,it can be suggested that the adjustment factor of 0.2 is also applicable to Malaysian hardwood timbers with a characteristic density above 700 kg/m3.展开更多
The highway capacity manual(HCM)provides a formula to calculate the heavy vehicle adjustment factor(fHV)as a function of passenger car equivalent factors for the heavy vehicle(ET).However,a significant drawback is tha...The highway capacity manual(HCM)provides a formula to calculate the heavy vehicle adjustment factor(fHV)as a function of passenger car equivalent factors for the heavy vehicle(ET).However,a significant drawback is that the methodology was established solely based on human-driven passenger cars(HDPC)and human-driven heavy vehicles(HDHV).Due to automated passenger cars(APCs),a new adjustment factor(fAV)might be expected.This study simulated traffic flows at different percentages of HDHVs and APCs to investigate the impacts of HDHVs and APCs on freeway capacity by analyzing their influence on fHV and fAV values.The simulation determined observed adjustment factors at different percentages of HDHVs and APCs(fobserved).The HCM formula was used to calculate(fHCM).Modifications to the HCM formula are proposed,and vehicle adjustment factors due to HDHVs and APCs were calculated(fproposed).Results showed that,in the presence of APCs,while fobserved and fHCM were statistically significantly different,fobserved and fproposed were statistically equal.Hence,this study recommends using the proposed formula when determining vehicle adjustment factors(fproposed)due to HDHVs and APCs in the traffic stream.展开更多
Hybrid energy storage systems(HESSs)involved in secondary frequency regulation(FR)can overcome the technical limitations of single energy storage systems(ESSs).However,coordinating the control of ESSs with differing c...Hybrid energy storage systems(HESSs)involved in secondary frequency regulation(FR)can overcome the technical limitations of single energy storage systems(ESSs).However,coordinating the control of ESSs with differing characteristics remains a major challenge.In this study,we propose a cooperative control strategy for HESSs in automatic generation control FR.First,the maximum output dynamic adjustment factor of the flywheel energy storage system(FESS)and the real-time dispatchable power of ESSs are introduced to constrain the charge/discharge power of ESSs.Subsequently,a coordinated allocation strategy of prioritizing the FESS,i.e.,battery energy storage system(BESS)supplementation,is adopted to pre-allocate the FR power of HESSs between BESSs and FESSs.Second,we minimized the energy loss and balanced the state of charge(SOC)of each ESS to redistribute the pre-allocated FR power of each ESS among the internal energy storage units.Finally,we conducted a simulation analysis using actual operational data.The findings indicate that the proposed strategy can reduce the lifetime loss of the BESS and enhance the continuous operating capability of the FESS.This system can also reduce the energy loss in each ESS,thereby effectively maintaining the SOC equilibrium of each system.展开更多
目的 分析1990—2021年海南省肝硬化疾病负担变化趋势及其影响因素。方法 利用2021年全球疾病负担研究数据,使用Joinpoint回归模型分析1990—2021年海南省居民肝硬化的发病率、死亡率、伤残调整寿命年(disability adjusted life years,D...目的 分析1990—2021年海南省肝硬化疾病负担变化趋势及其影响因素。方法 利用2021年全球疾病负担研究数据,使用Joinpoint回归模型分析1990—2021年海南省居民肝硬化的发病率、死亡率、伤残调整寿命年(disability adjusted life years,DALY)。结果 1990—2021年海南省居民肝硬化的标化发病率为729.81/10万~734.78/10万,平均年度变化百分比(average annual percentage change,AAPC)为-0.03%(t=-0.51,P=0.607),男性和女性AAPC分别为-0.4%(t=-5.85,P<0.001)和0.2%(t=0.91,P=0.365);标化死亡率为8.28/10万~14.75/10万,AAPC为-1.8%(t=-21.11,P<0.001),男性AAPC为-1.3%(t=-11.10,P<0.001),女性AAPC为-3.0%(t=-35.40,P<0.001);标化DALY率为243.71/10万~446.47/10万,AAPC为-1.9%(t=-19.65,P<0.001),女性AAPC为-3.3%(t=-40.66,P<0.001),男性AAPC为-1.41%(t=-10.66,P<0.001);标化过早死亡损失寿命年(years of life lost,YLL)率和标化伤残损失寿命年(years lived with disability,YLD)率均呈现下降趋势,AAPC分别为-1.9%(t=-19.28,P<0.001)和-1.2%(t=-11.29,P<0.001)。在肝硬化疾病负担影响因素中,饮酒导致的DALY的AAPC为1.6%(t=11.27,P<0.001),标化DALY率的AAPC为-1.4%(t=-9.27,P<0.001)。结论 海南省肝硬化疾病负担总体呈下降趋势,饮酒是海南省肝硬化的主要行为危险因素,应加强肝硬化的早诊早治工作。展开更多
摘要A new kind of optimal fuzzy PID controller is proposed, which contains two parts. One is an on line fuzzy inference system, and the other is a conventional PID controller. In the fuzzy inference system, three adjustable factors x p, x i , and x d are introduced. Their functions are to further modify and optimize the result of the fuzzy inference so as to make the controller have the optimal control effect on a given object. The optimal values of these adjustable factors are determined based on the ITAE criterion and the Nelder and Mead′s flexible polyhedron search algorithm. This optimal fuzzy PID controller has been used to control the executive motor of the intelligent artificial leg designed by the authors. The result of computer simulation indicates that this controller is very effective and can be widely used to control different kinds of objects and processes.
基金This work was supported in part by the Natural Science Foundation of Henan Province,and the specific grant number is 232300420301the initial of author is P.L.,the URL to the sponsors’websites is http://gffzz4c68f762254d4f5csvnffc6xff0bp65wk.ffgz.tsg.suse.edu.cn/(accessed on 09 February 2025)And this work was also supported in part by the Fundamental Research Funds for the Universities of Henan Province,and the specific grant number is NSFRF220425,the initial of author is P.L.,the URL to sponsors websites is http://gffzz58eb77af07924941hvnffc6xff0bp65wk.ffgz.tsg.suse.edu.cn/web/index.do(accessed on 09 February 2025).
摘要The photovoltaic(PV)output process is inherently complex,often disrupted by a multitude of meteoro-logical factors,while conventional detection methods at PV power stations prove inadequate,compromising prediction accuracy.To address this challenge,this paper introduces a power prediction method that leverages modal switching(MS),weight factor adjustment(WFA),and parallel long short-term memory(PALSTM).Initially,historical PV power station data is categorized into distinct modes based on global horizontal irradiance and converted solar angles.Correlation analysis is then employed to evaluate the impact of various meteorological factors on PV power,selecting those with strong correlations for each specific mode.Subsequently,the weights of meteorological parameters are optimized and adjusted,and a PALSTM neural network is constructed,with its parallel modal parameters refined through training.Depending on the prediction time and input data mode characteristics,the appropriate mode channel is selected to forecast PV power station generation.Ultimately,the feasibility of this method is validated through an illustrative analysis of measured data from an Australian PV power station.Comparative test results underscore the method’s advantages,particularly in scenarios where existing detection methods are lacking and meteorological factors frequently fluctuate,demonstrating its superior prediction accuracy and stability.
基金funded by Geran Penyelidikan Khas(GPK),(600-RMC/GPK 5/3(071/2020)).
摘要The depth adjustment factor for bending strength stated in Eurocode 5(EC5)is only applicable to timbers having a characteristic density below 700 kg/m3.However,most Malaysian timbers are hardwood,some with a characteristic density reaching above 700 kg/m3.Therefore,the objective of this study was to examine whether the depth adjustment factor stipulated in EC5 is valid for Malaysian hardwood timbers.Six timber species were selected for this study,namely Kapur(Dryobalanops C.F.Gaertn.),Kempas(Koompassia Maingay ex Benth.),Keruing(Dipterocarpus C.F.Gaertn.),Light red meranti(Shorea Roxb.ex C.F.Gaertn.),Geronggang(Cratoxylum Blume)and Balau(Shorea Roxb.ex C.F.Gaertn.).The determination of bending strength and characteristic density was conducted according to BS EN 408:2010 and BS EN 384:2016,respectively.A graph for mean bending strength vs.(150/h)was plotted for each timber species.The power function was selected to analyze the relationship between the two variables.The power of the regression equations varied depending on the characteristic density of the timber species.For species with a characteristic density below 700 kg/m3,such as Kapur,Keruing,and Light red meranti,the power was between 0.16 to 0.17.In contrast,for species having a characteristic density above 700 kg/m3,namely Kempas and Balau,the power was higher at 0.23 and 0.24,respectively.Geronggang was an exception to this pattern.These values are close to the depth adjustment factor given in EC5,which is 0.2.Based on the results,it can be suggested that the adjustment factor of 0.2 is also applicable to Malaysian hardwood timbers with a characteristic density above 700 kg/m3.
摘要The highway capacity manual(HCM)provides a formula to calculate the heavy vehicle adjustment factor(fHV)as a function of passenger car equivalent factors for the heavy vehicle(ET).However,a significant drawback is that the methodology was established solely based on human-driven passenger cars(HDPC)and human-driven heavy vehicles(HDHV).Due to automated passenger cars(APCs),a new adjustment factor(fAV)might be expected.This study simulated traffic flows at different percentages of HDHVs and APCs to investigate the impacts of HDHVs and APCs on freeway capacity by analyzing their influence on fHV and fAV values.The simulation determined observed adjustment factors at different percentages of HDHVs and APCs(fobserved).The HCM formula was used to calculate(fHCM).Modifications to the HCM formula are proposed,and vehicle adjustment factors due to HDHVs and APCs were calculated(fproposed).Results showed that,in the presence of APCs,while fobserved and fHCM were statistically significantly different,fobserved and fproposed were statistically equal.Hence,this study recommends using the proposed formula when determining vehicle adjustment factors(fproposed)due to HDHVs and APCs in the traffic stream.
基金supported by the Key Projects of the National Natural Science Foundation of China(No.:52337004).
摘要Hybrid energy storage systems(HESSs)involved in secondary frequency regulation(FR)can overcome the technical limitations of single energy storage systems(ESSs).However,coordinating the control of ESSs with differing characteristics remains a major challenge.In this study,we propose a cooperative control strategy for HESSs in automatic generation control FR.First,the maximum output dynamic adjustment factor of the flywheel energy storage system(FESS)and the real-time dispatchable power of ESSs are introduced to constrain the charge/discharge power of ESSs.Subsequently,a coordinated allocation strategy of prioritizing the FESS,i.e.,battery energy storage system(BESS)supplementation,is adopted to pre-allocate the FR power of HESSs between BESSs and FESSs.Second,we minimized the energy loss and balanced the state of charge(SOC)of each ESS to redistribute the pre-allocated FR power of each ESS among the internal energy storage units.Finally,we conducted a simulation analysis using actual operational data.The findings indicate that the proposed strategy can reduce the lifetime loss of the BESS and enhance the continuous operating capability of the FESS.This system can also reduce the energy loss in each ESS,thereby effectively maintaining the SOC equilibrium of each system.
摘要目的 分析1990—2021年海南省肝硬化疾病负担变化趋势及其影响因素。方法 利用2021年全球疾病负担研究数据,使用Joinpoint回归模型分析1990—2021年海南省居民肝硬化的发病率、死亡率、伤残调整寿命年(disability adjusted life years,DALY)。结果 1990—2021年海南省居民肝硬化的标化发病率为729.81/10万~734.78/10万,平均年度变化百分比(average annual percentage change,AAPC)为-0.03%(t=-0.51,P=0.607),男性和女性AAPC分别为-0.4%(t=-5.85,P<0.001)和0.2%(t=0.91,P=0.365);标化死亡率为8.28/10万~14.75/10万,AAPC为-1.8%(t=-21.11,P<0.001),男性AAPC为-1.3%(t=-11.10,P<0.001),女性AAPC为-3.0%(t=-35.40,P<0.001);标化DALY率为243.71/10万~446.47/10万,AAPC为-1.9%(t=-19.65,P<0.001),女性AAPC为-3.3%(t=-40.66,P<0.001),男性AAPC为-1.41%(t=-10.66,P<0.001);标化过早死亡损失寿命年(years of life lost,YLL)率和标化伤残损失寿命年(years lived with disability,YLD)率均呈现下降趋势,AAPC分别为-1.9%(t=-19.28,P<0.001)和-1.2%(t=-11.29,P<0.001)。在肝硬化疾病负担影响因素中,饮酒导致的DALY的AAPC为1.6%(t=11.27,P<0.001),标化DALY率的AAPC为-1.4%(t=-9.27,P<0.001)。结论 海南省肝硬化疾病负担总体呈下降趋势,饮酒是海南省肝硬化的主要行为危险因素,应加强肝硬化的早诊早治工作。