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21.
用数值模拟方法对一四股流板翅式换热器分别施加流量、进口温度的阶跃变化,获得其出口温度动态的响应曲线;用理论方法研究了其传染函数的系数,从而得到了四股流换热器的传递函数,并对其结果进行了分析,所得的四股流板翅式换热器的传递函数系数炎其自动控制试验提供了理论依据。  相似文献   
22.
采用CMOS工艺设计了一种零温度系数的带隙基准与零温度系数欠压闭锁(UVLO)的复用电路。由于这种复用,使其与传统的采用BiCMOS或CMOS工艺设计的电路相比,工艺成本低,易于实现。电路由通过改进的带隙结构产生零温度系数的基准电压,并同时检测输入电压,产生对温度和工艺不敏感的输入电压检测信号跳变阈值,实现欠压闭锁。同时通过反馈实现迟滞,克服了单一阈值的弱抗干扰能力。  相似文献   
23.
本文建立了随机约束条件下线性回归模型中的Cook距离,讨论了它的统计性质,并找到了它与相关系数、复相关系数及广义相关系数之间的关系。  相似文献   
24.
This paper considers a regression model in which coefficients obtained from a previous regression are themselves the object of analysis. It is shown that the parameters of interest can be obtained in two ways: pooling across observations and subsamples, or a two-stage process of first estimating the coefficients within each subsample, and then using these coefficients as dependent variables in a second stage regression. The relative properties of these estimators are analyzed, and the conditions under which the two estimators are equivalent are derived.  相似文献   
25.
对等惯、等轴性且具有固定端的n圆盘系统的特征多项式进行了分析。得出了其系数与二项式系数的一个有趣的关系;并对特征值的取值进行了有关讨论;最后也给出了得到的三个组合恒等式。  相似文献   
26.
运用协整回归和误差修正模型,以山西省为例,实证分析农村劳动力转移对现代农业的影响。结果表明,19962011年,农村劳动生产率、财政支农资金比例和城镇化水平的对数与农村转移劳动力比例之间存在协整关系,且误差修正机制存在;β系数进一步表明农村转移劳动力对农业现代化的影响作用最大,并且前者是后者的Granger因。证实了现代农业驱动处于人口转移驱动型阶段,尚未进入城镇化驱动阶段。据此提出建议:继续积极鼓励和引导农村劳动力有序、健康转移;提高财政支农比例,提升财政支农资金运用效率;对城镇化模式进行科学动态调整,纠正城镇化偏差。  相似文献   
27.
I illustrate likelihood methods for estimating the consequences of shrinkage along any ridge path as well as methods for picking a two-hyperparameter path of optimal curvature and the optimal point on that path. In addition to my published "classical" methods, I also illustrate both the empirical Bayes and the random coefficient maximum likelihood approaches. Traces of risks for known parameters and losses for simulated responses are followed by traces of estimates that can reveal the same general information.  相似文献   
28.
A reconciliation is offered for the diverse test results on Friedman's permanent income hypothesis. A large data sample of those receiving windfall income in the Bureau of Labor Statistics' 1972–1973 Consumer Expenditure Survey is divided according to the size of the windfall relative to estimated permanent income. A pattern of a declining marginal propensity to consume windfall income as the relative size of the windfall increases is apparent. These results support the permanent income hypothesis for relatively large windfalls.  相似文献   
29.
We propose a heterogeneous time-varying panel data model with a latent group structure that allows the coefficients to vary over both individuals and time. We assume that the coefficients change smoothly over time and form different unobserved groups. When treated as smooth functions of time, the individual functional coefficients are heterogeneous across groups but homogeneous within a group. We propose a penalized-sieve-estimation-based classifier-Lasso (C-Lasso) procedure to identify the individuals’ membership and to estimate the group-specific functional coefficients in a single step. The classification exhibits the desirable property of uniform consistency. The C-Lasso estimators and their post-Lasso versions achieve the oracle property so that the group-specific functional coefficients can be estimated as well as if the individuals’ membership were known. Several extensions are discussed. Simulations demonstrate excellent finite sample performance of the approach in both classification and estimation. We apply our method to study the heterogeneous trending behavior of GDP per capita across 91 countries for the period 1960–2012 and find four latent groups.  相似文献   
30.
The inverse Gaussian distribution is often suited for modeling positive and/or positively skewed data (see Chhikara and Folks, 1989 Chhikara , R. S. , Folks , J. L. ( 1989 ). The Inverse Gaussian Distribution . New York : Marcel Dekker . [Google Scholar]) and presents an interesting alternative to the Gaussian model in such cases. We note here that overlap coefficients and their variants are widely studied in the literature for Gaussian populations (see Mulekar and Mishra, 1994 Mulekar , M. , Mishra , S. N. ( 1994 ). Overlap coefficients of two normal densities: equal means case . J. Japan. Statist. Soc. 24 : 169180 . [Google Scholar], 2000 Mulekar , M. , Mishra , S. N. ( 2000 ). Confidence interval estimation of overlap: equal means case . Computat. Statist. Data Anal. 34 : 121137 .[Crossref], [Web of Science ®] [Google Scholar], and references therein for further details). This article studies the properties and addresses point estimation for large samples of commonly used measures of overlap when the populations are described by inverse Gaussian distributions. The bias and mean square error properties of the estimators are studied through a simulation study.  相似文献   
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