校核、验证与确认(verification,validation,and accreditation,VV&A)是保证仿真模型可信度的关键手段,其中模型验证是核心环节。针对导弹飞行仿真模型结果验证存在的参考数据不可获得、参考数据来源多样、专家验证主观性强等问题,...校核、验证与确认(verification,validation,and accreditation,VV&A)是保证仿真模型可信度的关键手段,其中模型验证是核心环节。针对导弹飞行仿真模型结果验证存在的参考数据不可获得、参考数据来源多样、专家验证主观性强等问题,提出一种基于时间序列分段特征提取的导弹飞行仿真模型结果验证方法。提出了一种综合的时间序列分段线性方法,由基于二阶导数提取趋势边缘点的线性分段算法和基于极值点优化的Top-Down线性分段算法两部分组成,以实现对导弹飞行仿真数据和参考数据进行有效的线性分段表示。基于上述分段结果,对各段时间序列的均值、方差、斜率等特征进行提取,以辅助专家进行验证,从而降低验证中的主观性;或者直接利用TIC系数法、动态时间规整(dynamic time warping,DTW)等方法进行客观的相似性分析。通过充分利用时间序列的分段特征,可实现各种情形下的导弹飞行仿真模型结果验证。通过一个导弹模型结果验证案例演示了所提方法的可行性和有效性。展开更多
The efficiency of the actual Stirling engine is much lower than the ideal Carnot cycle efficiency.To obtain more precise efficiency for Stirling engines,this paper proposes a modified Stirling cycle with a more accura...The efficiency of the actual Stirling engine is much lower than the ideal Carnot cycle efficiency.To obtain more precise efficiency for Stirling engines,this paper proposes a modified Stirling cycle with a more accurate heat transfer process in Stirling engines based on a thermodynamic function called available potential.The finite-time thermodynamic method is used to analyze the model performance under constant heat source temperature,finite temperature difference heat transfer,and incomplete regenerative processes.A new polytropic process is introduced to model the heat transfer between the working fluid and external heat sources in which only heat above ambient temperature is converted into technical work.The regenerator is divided into numerous smaller heat reservoirs with individual temperature to analyze the incomplete regenerative processes.The expressions of the output power and thermal efficiency are obtained based on the modified irreversible Stirling cycle,and the effects of irreversible losses are analyzed to evaluate the performance of the proposed model.Results indicate that the efficiency of the modified cycle is much lower than that of the ideal Stirling cycle with an isothermal process.With the increase of the average heat transfer temperature difference,there exists an optimum value for the power of the irreversible cycle.The optimum power of the model was obtained for varying thermodynamic parameters by optimizing the average heat transfer temperature difference between the hot and cold sides.To optimize the irreversible model,the multi-objective optimization analysis is carried out based on NSGA-Ⅱ,which results in an optimized output power of 40.87 kW and an optimized thermal efficiency of 44%.展开更多
为了提高微震震源定位精度和算法鲁棒性,研究了基于到时的定位算法的目标函数构建和时空区域信息使用。仿真实验基于Numpy,采用理想到时+随机扰动来模拟生产情况。结果表明:到时定位算法中常用的L_(1)和L_(2)目标函数对实际震源存在偏...为了提高微震震源定位精度和算法鲁棒性,研究了基于到时的定位算法的目标函数构建和时空区域信息使用。仿真实验基于Numpy,采用理想到时+随机扰动来模拟生产情况。结果表明:到时定位算法中常用的L_(1)和L_(2)目标函数对实际震源存在偏离且偏离现象非常普遍。为了减轻伪震源问题,使用到时偏差的似然函数作为基础函数,聚合时空邻域的单点基础函数作为目标函数;新构建的4维区域分布算法(Distribution of 4-Dimention Area Algorithm,D4DA)在2次标定炮定位中将定位误差分别降低了14%和26%。展开更多
This paper proposes a new approach for multi-objective robust control. The approach extends the standard generalized l2 (Gl2) and generalized H2 (GH2) conditions to a set of new linear matrix inequality (LMI) constra...This paper proposes a new approach for multi-objective robust control. The approach extends the standard generalized l2 (Gl2) and generalized H2 (GH2) conditions to a set of new linear matrix inequality (LMI) constraints based on a new stability condition. A technique for variable parameterization is introduced to the multi-objective control problem to preserve the linearity of the synthesis variables. Consequently, the multi-channel multi-objective mixed Gl2/GH2 control problem can be solved less conservatively using computationally tractable algorithms developed in the paper.展开更多
文摘校核、验证与确认(verification,validation,and accreditation,VV&A)是保证仿真模型可信度的关键手段,其中模型验证是核心环节。针对导弹飞行仿真模型结果验证存在的参考数据不可获得、参考数据来源多样、专家验证主观性强等问题,提出一种基于时间序列分段特征提取的导弹飞行仿真模型结果验证方法。提出了一种综合的时间序列分段线性方法,由基于二阶导数提取趋势边缘点的线性分段算法和基于极值点优化的Top-Down线性分段算法两部分组成,以实现对导弹飞行仿真数据和参考数据进行有效的线性分段表示。基于上述分段结果,对各段时间序列的均值、方差、斜率等特征进行提取,以辅助专家进行验证,从而降低验证中的主观性;或者直接利用TIC系数法、动态时间规整(dynamic time warping,DTW)等方法进行客观的相似性分析。通过充分利用时间序列的分段特征,可实现各种情形下的导弹飞行仿真模型结果验证。通过一个导弹模型结果验证案例演示了所提方法的可行性和有效性。
基金supported by the National Natural Science Foundation of China(Grant No.51736004)。
文摘The efficiency of the actual Stirling engine is much lower than the ideal Carnot cycle efficiency.To obtain more precise efficiency for Stirling engines,this paper proposes a modified Stirling cycle with a more accurate heat transfer process in Stirling engines based on a thermodynamic function called available potential.The finite-time thermodynamic method is used to analyze the model performance under constant heat source temperature,finite temperature difference heat transfer,and incomplete regenerative processes.A new polytropic process is introduced to model the heat transfer between the working fluid and external heat sources in which only heat above ambient temperature is converted into technical work.The regenerator is divided into numerous smaller heat reservoirs with individual temperature to analyze the incomplete regenerative processes.The expressions of the output power and thermal efficiency are obtained based on the modified irreversible Stirling cycle,and the effects of irreversible losses are analyzed to evaluate the performance of the proposed model.Results indicate that the efficiency of the modified cycle is much lower than that of the ideal Stirling cycle with an isothermal process.With the increase of the average heat transfer temperature difference,there exists an optimum value for the power of the irreversible cycle.The optimum power of the model was obtained for varying thermodynamic parameters by optimizing the average heat transfer temperature difference between the hot and cold sides.To optimize the irreversible model,the multi-objective optimization analysis is carried out based on NSGA-Ⅱ,which results in an optimized output power of 40.87 kW and an optimized thermal efficiency of 44%.
文摘为了提高微震震源定位精度和算法鲁棒性,研究了基于到时的定位算法的目标函数构建和时空区域信息使用。仿真实验基于Numpy,采用理想到时+随机扰动来模拟生产情况。结果表明:到时定位算法中常用的L_(1)和L_(2)目标函数对实际震源存在偏离且偏离现象非常普遍。为了减轻伪震源问题,使用到时偏差的似然函数作为基础函数,聚合时空邻域的单点基础函数作为目标函数;新构建的4维区域分布算法(Distribution of 4-Dimention Area Algorithm,D4DA)在2次标定炮定位中将定位误差分别降低了14%和26%。
基金Project supported by the National Natural Science Foundation ofChina (No. 60374028) and the Scientific Research Foundation forReturned Overseas Chinese Scholars Ministry of Education (No.[2004]176)
文摘This paper proposes a new approach for multi-objective robust control. The approach extends the standard generalized l2 (Gl2) and generalized H2 (GH2) conditions to a set of new linear matrix inequality (LMI) constraints based on a new stability condition. A technique for variable parameterization is introduced to the multi-objective control problem to preserve the linearity of the synthesis variables. Consequently, the multi-channel multi-objective mixed Gl2/GH2 control problem can be solved less conservatively using computationally tractable algorithms developed in the paper.
