Aiming at the Four-Dimensional Variation source term inversion algorithm proposed earlier,the observation error regularization factor is introduced to improve the prediction accuracy of the diffusion model,and an impr...Aiming at the Four-Dimensional Variation source term inversion algorithm proposed earlier,the observation error regularization factor is introduced to improve the prediction accuracy of the diffusion model,and an improved Four-Dimensional Variation source term inversion algorithm with observation error regularization(OER-4DVAR STI model)is formed.Firstly,by constructing the inversion process and basic model of OER-4DVAR STI model,its basic principle and logical structure are studied.Secondly,the observation error regularization factor estimation method based on Bayesian optimization is proposed,and the error factor is separated and optimized by two parameters:error statistical time and deviation degree.Finally,the scientific,feasible and advanced nature of the OER-4DVAR STI model are verified by numerical simulation and tracer test data.The experimental results show that OER-4DVAR STI model can better reverse calculate the hazard source term information under the conditions of high atmospheric stability and flat underlying surface.Compared with the previous inversion algorithm,the source intensity estimation accuracy of OER-4DVAR STI model is improved by about 46.97%,and the source location estimation accuracy is improved by about 26.72%.展开更多
Aimed at unbalance of soil temperature field of ground source heat pump system, solar aided energy storage system was established. In solar assisted ground-source heat pump (SAGSHP) system with soil storage, solar ene...Aimed at unbalance of soil temperature field of ground source heat pump system, solar aided energy storage system was established. In solar assisted ground-source heat pump (SAGSHP) system with soil storage, solar energy collected in three seasons was stored in the soil by vertical U type soil exchangers. The heat abstracted by the ground-source heat pump and collected by the solar collector was employed to heating. Some of the soil heat exchangers were used to store solar energy in the soil so as to be used in next winter after this heating period; and the others were used to extract cooling energy directly in the soil by circulation pump for air conditioning in summer. After that solar energy began to be stored in the soil and ended before heating period. Three dimensional dynamic numerical simulations were built for soil and soil heat exchanger through finite element method. Simulation was done in different strata month by month. Variation and restoration of soil temperature were studied. Economy and reliability of long term SAGSHP system were revealed. It can be seen that soil temperature is about 3 ℃ higher than the original one after one year's running. It is beneficial for the system to operate for long period.展开更多
随着电子健康记录(electronic health record,EHR)在医学研究中的广泛应用,其多源异构性日益成为影响病例对照研究效度的关键问题。不同医疗系统在数据来源、格式、编码标准及人群覆盖方面的差异,易引发选择偏倚、信息偏倚、混杂偏倚及...随着电子健康记录(electronic health record,EHR)在医学研究中的广泛应用,其多源异构性日益成为影响病例对照研究效度的关键问题。不同医疗系统在数据来源、格式、编码标准及人群覆盖方面的差异,易引发选择偏倚、信息偏倚、混杂偏倚及不朽时间偏倚,从而削弱因果推断的可靠性。本文系统剖析了EHR异构性的来源与特征,包括数据结构差异、编码不一致及人群异质性,探讨其在各类偏倚中的作用机制,结合实证案例揭示其对研究结果的影响;随后整合数据标准化、多重插补、样本加权、倾向性评分匹配(特别是高维倾向性评分hd-PSM)、工具变量分析及DAG辅助调整等技术,构建了偏倚控制与验证的系统性框架。将标准化的数据处理流程、严谨的研究设计、先进的分析性控制策略与客观的效果验证方法融为一体的综合框架,对于从EHR数据中获得稳健可信的科学结论至关重要。展开更多
基金Ministry of Science and Technology of the People’s Republic of China for its support and guidance(Grant No.2018YFC0214100)。
文摘Aiming at the Four-Dimensional Variation source term inversion algorithm proposed earlier,the observation error regularization factor is introduced to improve the prediction accuracy of the diffusion model,and an improved Four-Dimensional Variation source term inversion algorithm with observation error regularization(OER-4DVAR STI model)is formed.Firstly,by constructing the inversion process and basic model of OER-4DVAR STI model,its basic principle and logical structure are studied.Secondly,the observation error regularization factor estimation method based on Bayesian optimization is proposed,and the error factor is separated and optimized by two parameters:error statistical time and deviation degree.Finally,the scientific,feasible and advanced nature of the OER-4DVAR STI model are verified by numerical simulation and tracer test data.The experimental results show that OER-4DVAR STI model can better reverse calculate the hazard source term information under the conditions of high atmospheric stability and flat underlying surface.Compared with the previous inversion algorithm,the source intensity estimation accuracy of OER-4DVAR STI model is improved by about 46.97%,and the source location estimation accuracy is improved by about 26.72%.
基金Project(GC06A316) supported by the Key Technologies Research and Development Program of Heilongjiang Province, China Project(11531038) supported by the Program of the Educational Commission of Heilongjiang Province of China.
文摘Aimed at unbalance of soil temperature field of ground source heat pump system, solar aided energy storage system was established. In solar assisted ground-source heat pump (SAGSHP) system with soil storage, solar energy collected in three seasons was stored in the soil by vertical U type soil exchangers. The heat abstracted by the ground-source heat pump and collected by the solar collector was employed to heating. Some of the soil heat exchangers were used to store solar energy in the soil so as to be used in next winter after this heating period; and the others were used to extract cooling energy directly in the soil by circulation pump for air conditioning in summer. After that solar energy began to be stored in the soil and ended before heating period. Three dimensional dynamic numerical simulations were built for soil and soil heat exchanger through finite element method. Simulation was done in different strata month by month. Variation and restoration of soil temperature were studied. Economy and reliability of long term SAGSHP system were revealed. It can be seen that soil temperature is about 3 ℃ higher than the original one after one year's running. It is beneficial for the system to operate for long period.
文摘随着电子健康记录(electronic health record,EHR)在医学研究中的广泛应用,其多源异构性日益成为影响病例对照研究效度的关键问题。不同医疗系统在数据来源、格式、编码标准及人群覆盖方面的差异,易引发选择偏倚、信息偏倚、混杂偏倚及不朽时间偏倚,从而削弱因果推断的可靠性。本文系统剖析了EHR异构性的来源与特征,包括数据结构差异、编码不一致及人群异质性,探讨其在各类偏倚中的作用机制,结合实证案例揭示其对研究结果的影响;随后整合数据标准化、多重插补、样本加权、倾向性评分匹配(特别是高维倾向性评分hd-PSM)、工具变量分析及DAG辅助调整等技术,构建了偏倚控制与验证的系统性框架。将标准化的数据处理流程、严谨的研究设计、先进的分析性控制策略与客观的效果验证方法融为一体的综合框架,对于从EHR数据中获得稳健可信的科学结论至关重要。
