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对设计阵X呈病态的线性回归模型,提出回归系数有偏估计的一种广义岭型主成分估计.均方误差意义下,在一定条件下它优于岭型主成分估计、Stein型主成分估计.证明了它的可容许性和较强的抗干扰性以及Pit-man准则下的优良性. 相似文献
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熊幼林 《数学学习与研究(教研版)》2014,(9):121
本文针对岭估计和主成分估计的不足,从模型病态的根本原因出发,将模型分解成两个线性回归模型,对参数的两部分分别采用LS估计和岭估计,从而定义了一个新的估计,即主成分—岭估计.通过研究该估计的性质,证明了在均方误差意义下,主成分—岭估计优于岭估计、0-c型岭估计和0-K型广义岭估计,从而为病态线性回归模型系数的估计提供了一种改进的技术途径.1.引言考虑线性回归模型:y=Xβ+e,E(e)=0,Cov(e)=σ2In.(1.1) 相似文献
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针对矩阵风队，给出了矩阵估计量的多种优良性准则，在这些准则下，得到了带有线性约束的多元回归系数的线性估计是可容许的充要条件，进而由于不同的线性约束所引起的可容许的估计类的不同，我们得到了不同的估计类之间的一种刻划。 相似文献
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《淮北师范大学学报》2016,(2)
文章对病态的混合系数线性模型Z(t)=[X(t)]′α+[Y(t)]′β提出一类新的估计h-K型估计,讨论此种估计的相关性质,利用Stein式压缩技术证明了可以改进岭估计(在均方误差意义下);同时给出参数的最优值满足的条件,证明h-K型岭估计的可容许性. 相似文献
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估计量的优良性是回归模型中的重要内容.本文讨论了在Pitman准则下,岭估计与Stein压缩估计的优良性,得到了岭估计优于Stein压缩估计的一个充分条件. 相似文献
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林路 《邵阳学院学报(社会科学版)》2000,(5)
通过同时考虑风险函数和样本大小 ,引出参数估计中的一种新效率 ,研究了这种效率的一些性质和充要条件 ,并讨论了回归分析中的最小二乘估计 ,岭估计和Stein估计的有效性 相似文献
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林路 《邵阳师范高等专科学校学报》2000,22(5):1-5
通过同时考虑风险函数和样本大小，引出参数估计中的一种新效率，研究了这种效率的一些性质和充要条件，并讨论了回归分析中的最小二乘估计，岭估计和Stein估计的有效性。 相似文献
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稳健性分析是判断估计值与真实值之间差异是否重要的一种方法。限制线性模型下的极大似然估计的稳健性是当前大家比较感兴趣的一个问题。笔者在前人的基础上,给出限制线性模型中极大似然估计对随机误差协方差矩阵的稳健性统计量,并对其进行分析,得出限制线性模型中极大似然估计对随机误差协方差矩阵不敏感。 相似文献
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在均方误差(MSE)准则下,给出了设计矩阵呈现病态时回归系数的分段优化估计,以及扩大了狭义岭估计类的范围. 相似文献
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储一民 《江苏广播电视大学学报》2000,11(4):7-9
考虑四阶线性微分方程组的离散谱估计,利用矩阵运算,分部积分和不等式估计等方法与技巧,得到了用前n个特征值来估计第n 1个特征值的上界的不等式,其估计系数与区间的几何度量无关,其结果在物理和力学等领域有着广泛的应用。 相似文献
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《海外英语》2007,(5):10-11
Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help? 相似文献
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《海外英语》2007,(4):36
There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love. 相似文献
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Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject. 相似文献
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Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities. 相似文献
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RUZBEHANI Mohsen 《重庆大学学报(英文版)》2004,3(1):20-25
1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec… 相似文献
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唐芳 《读与写:教育教学刊》2008,5(6)
During interview with English majors, it was found that a majority of students expressed disappointment with their experience of English literature classes. Students' dislike of learning English literature appears to be the major problem of teaching English literature in China. Reader response approach is a good way to solve this problem. In this paper, I explain the rationale behind the reader response approach, such as its origin, definition, features, assumptions, and strategies. Then I illustrate how reader response approach works as a teaching strategy by presenting several teaching models. At last I evaluate its usefuiness for teachers and present the advantages of reader response approach in Chinese context. 相似文献