The increasing integration of renewable energy sources highlights the urgent need for grid flexibility,with buildings serving as key controllable loads.In this context,accurately quantifying building flexibility is es...The increasing integration of renewable energy sources highlights the urgent need for grid flexibility,with buildings serving as key controllable loads.In this context,accurately quantifying building flexibility is essential for enabling effective demand-side management and ensuring reliable grid operations.However,several challenges hinder this quantification.To address these issues,this study proposes a comprehensive flexibility quantification framework.First,a novel RC-Mapping model incorporating an Enumerate-Comparison Method is proposed.The RC-Mapping model can capture the thermal behavior of both the building and the air conditioning system,while the Enumerate-Comparison Method can initialize state parameters in the RC-Mapping model.Compared with the conventional approach,as validated by the experiment,the proposed method can substantially improve RMSE for indoor temperature prediction from 0.542℃to 0.266℃,and the MAPE for flexibility quantification from 27.58%to 10.98%.Second,the study introduces the power reduction-duration curve and temperature variation curves to characterize flexibility from both grid and building perspectives.Specifically,based on the analysis of the power reduction-duration curve,this study provides a systematic analysis of four sources of flexibility and their underlying mechanisms,including the thermal storage of the building,the thermal storage of the HVAC system,the increase of coefficient of performance(COP),and the reduction in cooling load.Finally,the study investigates the impact of uncertainties in COP and internal heat gains on flexibility quantification.According to the result,it is recommended to slightly underestimate the COP and overestimate the internal heat gain schedule to improve the accuracy of flexibility quantification.展开更多
为实现锂离子电池荷电状态(state of charge,SOC)的准确估计,针对锂离子电池模型参数在线辨识精度不足和开路电压(open-circuit voltage,OCV)-SOC映射不准确等问题,提出一种锂离子电池自适应参数动态辨识和OCV-SOC映射修正方法。首先,...为实现锂离子电池荷电状态(state of charge,SOC)的准确估计,针对锂离子电池模型参数在线辨识精度不足和开路电压(open-circuit voltage,OCV)-SOC映射不准确等问题,提出一种锂离子电池自适应参数动态辨识和OCV-SOC映射修正方法。首先,构建二阶RC等效电路模型;其次,通过混合脉冲功率特征(hybrid pulsepower characteristic,HPPC)实验确定初始参数,并设计一种自适应的参数动态修正方法;最后,在不同温度条件下,构建充放电OCV-SOC映射关系曲线并进行拟合分析。实验结果表明,所提方法的参数辨识精度和OCV-SOC映射准确性均优于传统方法。展开更多
Based on the high frequency （HF） integrated radar cross section （RCS） calculation approach, a technique of detecting major scattering source is developed by using an appropriate arithmetic for scattering distribut...Based on the high frequency （HF） integrated radar cross section （RCS） calculation approach, a technique of detecting major scattering source is developed by using an appropriate arithmetic for scattering distribution and scattering source detection. For the perfect adaptability to targets and the HF of the HF integrated RCS calculation platform, this technique is suitable to solve large complex targets and has lower requirement to the target modeling. A comparison with the result of 2-D radar imaging confirms the accuracy and reliability of this technique in recognition of the major scattering source on complex targets. This technique provides the foundation for rapid integrated evaluation of the scattering performance and 3-D scattering model reconstruction of large complex targets.展开更多
In this paper, we show that every harmonic map from a compact K?hler manifold with uniformly RC-positive curvature to a Riemannian manifold with non-positive complex sectional curvature is constant. In particular, the...In this paper, we show that every harmonic map from a compact K?hler manifold with uniformly RC-positive curvature to a Riemannian manifold with non-positive complex sectional curvature is constant. In particular, there is no non-constant harmonic map from a compact K¨ahler manifold with positive holomorphic sectional curvature to a Riemannian manifold with non-positive complex sectional curvature.展开更多
基金the National Natural Science Foundation of China(No.52308104)the Shenzhen Science and Technology Program(Grant No.KCXST20221021111203007).
文摘The increasing integration of renewable energy sources highlights the urgent need for grid flexibility,with buildings serving as key controllable loads.In this context,accurately quantifying building flexibility is essential for enabling effective demand-side management and ensuring reliable grid operations.However,several challenges hinder this quantification.To address these issues,this study proposes a comprehensive flexibility quantification framework.First,a novel RC-Mapping model incorporating an Enumerate-Comparison Method is proposed.The RC-Mapping model can capture the thermal behavior of both the building and the air conditioning system,while the Enumerate-Comparison Method can initialize state parameters in the RC-Mapping model.Compared with the conventional approach,as validated by the experiment,the proposed method can substantially improve RMSE for indoor temperature prediction from 0.542℃to 0.266℃,and the MAPE for flexibility quantification from 27.58%to 10.98%.Second,the study introduces the power reduction-duration curve and temperature variation curves to characterize flexibility from both grid and building perspectives.Specifically,based on the analysis of the power reduction-duration curve,this study provides a systematic analysis of four sources of flexibility and their underlying mechanisms,including the thermal storage of the building,the thermal storage of the HVAC system,the increase of coefficient of performance(COP),and the reduction in cooling load.Finally,the study investigates the impact of uncertainties in COP and internal heat gains on flexibility quantification.According to the result,it is recommended to slightly underestimate the COP and overestimate the internal heat gain schedule to improve the accuracy of flexibility quantification.
基金supported by the National Natural Science Foundation of China (Grant No.90305026)
文摘Based on the high frequency （HF） integrated radar cross section （RCS） calculation approach, a technique of detecting major scattering source is developed by using an appropriate arithmetic for scattering distribution and scattering source detection. For the perfect adaptability to targets and the HF of the HF integrated RCS calculation platform, this technique is suitable to solve large complex targets and has lower requirement to the target modeling. A comparison with the result of 2-D radar imaging confirms the accuracy and reliability of this technique in recognition of the major scattering source on complex targets. This technique provides the foundation for rapid integrated evaluation of the scattering performance and 3-D scattering model reconstruction of large complex targets.
基金supported by China’s Recruitment Program of Global ExpertsNational Natural Science Foundation of China (Grant No. 11688101)
文摘In this paper, we show that every harmonic map from a compact K?hler manifold with uniformly RC-positive curvature to a Riemannian manifold with non-positive complex sectional curvature is constant. In particular, there is no non-constant harmonic map from a compact K¨ahler manifold with positive holomorphic sectional curvature to a Riemannian manifold with non-positive complex sectional curvature.
