本文以散射中心的指数衰减和模型(Damped Exponentials,DE)为基础将全极化散射中心的参数提取问题转化为全极化信息融合的约束总体最小二乘(Constrained Total Least Squares,CTLS)算法问题,据此计算出全部散射中心的距离参数和类型参数...本文以散射中心的指数衰减和模型(Damped Exponentials,DE)为基础将全极化散射中心的参数提取问题转化为全极化信息融合的约束总体最小二乘(Constrained Total Least Squares,CTLS)算法问题,据此计算出全部散射中心的距离参数和类型参数,然后利用最小二乘法求解全极化测量方程,得到每个散射中心的复幅度信息,从而获得每个散射中心的散射矩阵,其中散射矩阵与类型参数是密切相关的.然后分析了其中参数估计的精度问题,针对极化通道噪声方差的不同提出了相应的改进算法.最后进行了仿真,并与单极化散射中心估计参数作了对比,结果证实了该方法的有效性,为雷达极化信息与散射中心的有效融合提供了新方法.展开更多
Mutations in genes encoding a key component of cytotoxic granules, or the machinery for their release, underlie the systemic hyperiflammatory symptoms of familial hemophagocytic lymphohistiocytosis (FHL), a typically ...Mutations in genes encoding a key component of cytotoxic granules, or the machinery for their release, underlie the systemic hyperiflammatory symptoms of familial hemophagocytic lymphohistiocytosis (FHL), a typically pediatric onset autosomal recessive disorder with five known genetic subtypes (FHL1 - 5). FHL1 mutations have been mapped to chromosome 9, while the respective genes mutated in FHL2 (PRF1), FHL3 (UNC13D/Munc13-4), FHL4 (STX11) and FHL5 (STXBP2/ Munc18b/Munc18-2) have been identified. Perforin gene mutation directly affected the cytolytic activity of the cytotoxic granules. All the other FHL mutations appear to affect some aspect of cytotoxic granule exocytosis, resulting in impaired target cell killing by cytolytic T lymphocytes (CTLs) and/or natural killer (NK) cells. Recent findings suggest that failure to kill and detach from target cells, and prolonged synapse connection time, promote cytokine hypersecretion by the defective CTLs and NKs, which in turn result in systemic inflammation. Deciphering the genetics of FHL has contributed towards our understanding of the cell biology of hyperinflammatory responses and hemophagocytic lymphohistiocytosis accompanying pathological conditions such as cancer and viral infections.展开更多
In this paper,we consider the double-satellite localization under the earth ellipsoid model of the Wideband Geodetic System(WGS-84)using the Time Difference of Arrival(TDOA)and the Angle-of-Arrival(AOA).Several closed...In this paper,we consider the double-satellite localization under the earth ellipsoid model of the Wideband Geodetic System(WGS-84)using the Time Difference of Arrival(TDOA)and the Angle-of-Arrival(AOA).Several closed-form solution algorithms via the pseudolinearization of the measurement equations are presented to efficiently estimate the location.These algorithms include the Weighted Least Squares(WLS),the Constrained Total Least Squares(CTLS),and the Taylor-Series Iteration(TSI).Performance comparison of the proposed methods with the Cramér-Rao Lower Bound(CRLB)in the simulation is shown to demonstrate that the proposed algorithms are feasible and have stable performance.展开更多
文摘本文以散射中心的指数衰减和模型(Damped Exponentials,DE)为基础将全极化散射中心的参数提取问题转化为全极化信息融合的约束总体最小二乘(Constrained Total Least Squares,CTLS)算法问题,据此计算出全部散射中心的距离参数和类型参数,然后利用最小二乘法求解全极化测量方程,得到每个散射中心的复幅度信息,从而获得每个散射中心的散射矩阵,其中散射矩阵与类型参数是密切相关的.然后分析了其中参数估计的精度问题,针对极化通道噪声方差的不同提出了相应的改进算法.最后进行了仿真,并与单极化散射中心估计参数作了对比,结果证实了该方法的有效性,为雷达极化信息与散射中心的有效融合提供了新方法.
文摘Mutations in genes encoding a key component of cytotoxic granules, or the machinery for their release, underlie the systemic hyperiflammatory symptoms of familial hemophagocytic lymphohistiocytosis (FHL), a typically pediatric onset autosomal recessive disorder with five known genetic subtypes (FHL1 - 5). FHL1 mutations have been mapped to chromosome 9, while the respective genes mutated in FHL2 (PRF1), FHL3 (UNC13D/Munc13-4), FHL4 (STX11) and FHL5 (STXBP2/ Munc18b/Munc18-2) have been identified. Perforin gene mutation directly affected the cytolytic activity of the cytotoxic granules. All the other FHL mutations appear to affect some aspect of cytotoxic granule exocytosis, resulting in impaired target cell killing by cytolytic T lymphocytes (CTLs) and/or natural killer (NK) cells. Recent findings suggest that failure to kill and detach from target cells, and prolonged synapse connection time, promote cytokine hypersecretion by the defective CTLs and NKs, which in turn result in systemic inflammation. Deciphering the genetics of FHL has contributed towards our understanding of the cell biology of hyperinflammatory responses and hemophagocytic lymphohistiocytosis accompanying pathological conditions such as cancer and viral infections.
基金supported by Meteorological information and Signal Processing Key Laboratory of Sichuan Higher Education Institutes of Chengdu University of Information Technology,China(No.QXXCSYS201702)
文摘In this paper,we consider the double-satellite localization under the earth ellipsoid model of the Wideband Geodetic System(WGS-84)using the Time Difference of Arrival(TDOA)and the Angle-of-Arrival(AOA).Several closed-form solution algorithms via the pseudolinearization of the measurement equations are presented to efficiently estimate the location.These algorithms include the Weighted Least Squares(WLS),the Constrained Total Least Squares(CTLS),and the Taylor-Series Iteration(TSI).Performance comparison of the proposed methods with the Cramér-Rao Lower Bound(CRLB)in the simulation is shown to demonstrate that the proposed algorithms are feasible and have stable performance.
