针对AGC控制中火电机组响应时滞长、机组爬坡速率低的问题,提出了一种基于模糊控制策略的电池储能系统(Battery Energy Storage System,BESS)辅助AGC调频方法。该方法以区域控制偏差(Area Control Error,ACE)及其变化率作为模糊控制器...针对AGC控制中火电机组响应时滞长、机组爬坡速率低的问题,提出了一种基于模糊控制策略的电池储能系统(Battery Energy Storage System,BESS)辅助AGC调频方法。该方法以区域控制偏差(Area Control Error,ACE)及其变化率作为模糊控制器的输入量,BESS的参考功率变化量作为输出量,根据系统的运行状态调节BESS输出功率,辅助火电机组改善电网的动态调频性能。基于Matlab/Simulink平台的仿真结果表明,BESS能够迅速响应负荷扰动,减小了系统频率偏差和联络线功率偏差,降低了系统的超调作用,有助于提高电网AGC调频能力和增强系统的稳定性。展开更多
Based on the study on the city transport systems of some typical cities worldwide,this paper put forward that each city transport system has its own development mode,which is influenced by the city development plan,ec...Based on the study on the city transport systems of some typical cities worldwide,this paper put forward that each city transport system has its own development mode,which is influenced by the city development plan,economic development level,traveling vehicle composition etc..When some problems occur,such as the congestions caused by contradiction between the road capacity and vehicle composition,the city transport system may come into temporary maturity period.If the improvement for road system is limited meanwhile,optimized structure of vehicle composition should be an effective solution in this case.With the development of economy-internationalization,the development speed of city transport modernization is rapid.When traveling easiness is conflicting with efficiency,the advantages of public transport system become more obvious.Correspondingly,the superiority of two-wheel vehicles will reappear.Though the important function of two-wheel vehicles for alleviating city traffic problems is obvious,however,their development strategy must be reasonably proposed,and operation regulations must be performed accordingly.展开更多
【目的】研究2009-2018年三峡库区重庆段农业绿色全要素生产率(Green total factor productivity,GTFP),并探讨有关影响因素。【方法】将农业面源污染与碳排放纳入到评价体系之中,运用超效率基于松弛变量测度模型测算2009-2018年三峡库...【目的】研究2009-2018年三峡库区重庆段农业绿色全要素生产率(Green total factor productivity,GTFP),并探讨有关影响因素。【方法】将农业面源污染与碳排放纳入到评价体系之中,运用超效率基于松弛变量测度模型测算2009-2018年三峡库区重庆段农业GTFP指数,利用两步系统高斯混合模型实证分析有关影响因素。【结果】1)2009-2018年三峡库区重庆段整体农业GTFP平均每年上升19.9%,其中主要原因是技术进步指数的提高,而综合技术效率对整体农业GTFP的促进作用较小;2)10年发展过程中涪陵区发展最为明显,三峡库区城区段的东北部地区发展速度较快,而重庆主城都市区受制于经济结构调整等原因农业GTFP相对其他区县较低;3)公路基础设施、城镇化水平、金融支持程度以及适度的城乡收入差距对农业GTFP有正向促进作用,而财政支农和地区经济发展水平对农业GTFP有明显抑制作用。【结论】研究结果对于三峡库区重庆段农业绿色发展,对于筑牢长江上游重要生态屏障具有一定参考价值。展开更多
This paper is concerned with the estimating problem of seemingly unrelated （SU） non- parametric regression models. The authors propose a new method to estimate the unknown functions, which is an extension of the two...This paper is concerned with the estimating problem of seemingly unrelated （SU） non- parametric regression models. The authors propose a new method to estimate the unknown functions, which is an extension of the two-stage procedure in the longitudinal data framework. The authors show the resulted estimators are asymptotically normal and more efficient than those based on only the individual regression equation. Some simulation studies are given in support of the asymptotic results. A real data from an ongoing environmental epidemiologie study are used to illustrate the proposed procedure.展开更多
文摘针对AGC控制中火电机组响应时滞长、机组爬坡速率低的问题,提出了一种基于模糊控制策略的电池储能系统(Battery Energy Storage System,BESS)辅助AGC调频方法。该方法以区域控制偏差(Area Control Error,ACE)及其变化率作为模糊控制器的输入量,BESS的参考功率变化量作为输出量,根据系统的运行状态调节BESS输出功率,辅助火电机组改善电网的动态调频性能。基于Matlab/Simulink平台的仿真结果表明,BESS能够迅速响应负荷扰动,减小了系统频率偏差和联络线功率偏差,降低了系统的超调作用,有助于提高电网AGC调频能力和增强系统的稳定性。
文摘Based on the study on the city transport systems of some typical cities worldwide,this paper put forward that each city transport system has its own development mode,which is influenced by the city development plan,economic development level,traveling vehicle composition etc..When some problems occur,such as the congestions caused by contradiction between the road capacity and vehicle composition,the city transport system may come into temporary maturity period.If the improvement for road system is limited meanwhile,optimized structure of vehicle composition should be an effective solution in this case.With the development of economy-internationalization,the development speed of city transport modernization is rapid.When traveling easiness is conflicting with efficiency,the advantages of public transport system become more obvious.Correspondingly,the superiority of two-wheel vehicles will reappear.Though the important function of two-wheel vehicles for alleviating city traffic problems is obvious,however,their development strategy must be reasonably proposed,and operation regulations must be performed accordingly.
文摘【目的】研究2009-2018年三峡库区重庆段农业绿色全要素生产率(Green total factor productivity,GTFP),并探讨有关影响因素。【方法】将农业面源污染与碳排放纳入到评价体系之中,运用超效率基于松弛变量测度模型测算2009-2018年三峡库区重庆段农业GTFP指数,利用两步系统高斯混合模型实证分析有关影响因素。【结果】1)2009-2018年三峡库区重庆段整体农业GTFP平均每年上升19.9%,其中主要原因是技术进步指数的提高,而综合技术效率对整体农业GTFP的促进作用较小;2)10年发展过程中涪陵区发展最为明显,三峡库区城区段的东北部地区发展速度较快,而重庆主城都市区受制于经济结构调整等原因农业GTFP相对其他区县较低;3)公路基础设施、城镇化水平、金融支持程度以及适度的城乡收入差距对农业GTFP有正向促进作用,而财政支农和地区经济发展水平对农业GTFP有明显抑制作用。【结论】研究结果对于三峡库区重庆段农业绿色发展,对于筑牢长江上游重要生态屏障具有一定参考价值。
基金The research was supported in part by National Natural Science Foundation of China （NSFC） under Grants No. 10471140 and No. 10731010, the National Basic Research Program of China （973 Program） under Grant No. 2007CB814902, and Science Fund for Creative Research Groups.
文摘This paper is concerned with the estimating problem of seemingly unrelated （SU） non- parametric regression models. The authors propose a new method to estimate the unknown functions, which is an extension of the two-stage procedure in the longitudinal data framework. The authors show the resulted estimators are asymptotically normal and more efficient than those based on only the individual regression equation. Some simulation studies are given in support of the asymptotic results. A real data from an ongoing environmental epidemiologie study are used to illustrate the proposed procedure.
