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双频GPS数据的最优相位平滑伪距算法研究 被引量:11
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作者 郭建锋 欧吉坤中国科学院测量与地球物理研究所动力大地测量重点实验室 +1 位作者 袁运斌中国科学院测量与地球物理研究所动力大地测量重点实验室 王海涛 《自然科学进展》 北大核心 2008年第2期221-224,共4页
相位平滑伪距算法可以有效抑制多路径效应对伪距的不良影响,其计算效率高,对数据传输的要求低,因此在GPS数据处理领域受到了广泛的关注和研究.基于参数的最优估计理论,对Hatch滤波进行了改进,重点讨论了双频GPS数据的最优相位平滑伪距算... 相位平滑伪距算法可以有效抑制多路径效应对伪距的不良影响,其计算效率高,对数据传输的要求低,因此在GPS数据处理领域受到了广泛的关注和研究.基于参数的最优估计理论,对Hatch滤波进行了改进,重点讨论了双频GPS数据的最优相位平滑伪距算法.由该算法平滑得到的观测量与原始观测数据包含的信息量相同,即最优相位平滑伪距算法与非组合算法等价.理论研究结果表明该方法能够更有效地削弱多路径的影响,从而得到精度更高的定位结果. 展开更多
关键词 GPS 相位平滑伪距算法 HATCH滤波 时不变组合
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DYNAMIC PORTFOLIO CHOICE UNDER THE TIME-VARYING,JUMPS,AND KNIGHT UNCERTAINTY OF ASSET RETURN PROCESS 被引量:4
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作者 Chaolin HE Weidong MENG 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2012年第5期896-908,共13页
By introducing a stochastic element to the double-jump diffusion framework to measure the Knight uncertainty of asset return process, this paper builds the model of dynamic portfolio choice, which maximizes the expect... By introducing a stochastic element to the double-jump diffusion framework to measure the Knight uncertainty of asset return process, this paper builds the model of dynamic portfolio choice, which maximizes the expected utility of terminal portfolio wealth. Through specifying the state function of uncertainty-aversion, it utilizes the max-min method to derive the analytical solution of the model to study the effect of the time-varying, jumps, and Knight uncertainty of asset return process on dynamic portfolio choice and their interactions. Results of comparative analysis show: The time-varying results in positive or negative intertemporal hedging demand of portfolio, which depends on the coefficient of investor's risk aversion and the correlation coefficient between return shift and volatility shift; the jumps in asset return overall reduce investor's demand for the risky asset, which can be enhanced or weakened by the jumps in volatility; due to the existing of the Knight uncertainty, the investor avoids taking large position on risky asset, and the resulting is the improving of portfolio's steady and immunity. At last, an empirical study is done based on the samples of Shanghai Exchange Composite Index monthly return data from January 1997 to December 2009, which not only tests the theoretical analysis but also demonstrates that the proposed method in the paper is useful from the aspect of portfotio's equivalent utility. 展开更多
关键词 Conditional characteristic function dynamic portfolio JUMPS Knight uncertainty spec-tral generalized method of moments time-varying.
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