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991.
SUN Heping XU Jianqiao & B. DucarmeKey Laboratory of Dynamic Geodesy Institute of Geodesy Geophysics Chinese Academy of Sciences Wuhan China Observatoire Royal de Belgique Av. Circulaire B- Brussels BelgiumCorrespondence should be addressed to Sun Heping 《科学通报(英文版)》2003,48(9)
Based on the 28 series of the high precision and high minute sampling tidal gravity observations at 20 stations in Global Geodynamics Project (GGP) network, the resonant parameters of the Earth's nearly diurnal free wobble (including the eigenperiods, resonant strengths and quality factots) are precisely determined. The discrepancy of the eigenperiod between observed and theoretical values is studied, the important conclusion that the real dynamic ellipticity of the liquid core is about 5% larger than the one under the static equilibrium assumption is approved by using our gravity technique. The experimental Earth's tidal gravity models with considering the nearly diurnal free wobble of the Earth's liquid core are constructed in this study. The numerical results show that the difference among three experimental models is less than 0.1%, and the largest discrepancy compared to those widely used nowdays given by Dehant (1999) and Mathews (2001) is only about 0.4%. It can provide with the most recent real 相似文献
992.
993.
陈振韬 《湘潭大学自然科学学报》1989,11(4):12-17
我们在本文考虑带Robin边界条件的半线性Volterra生物群体反应扩散方程u_t=Lu-bu~2-uf*u其中L是具有光滑系数a_(ti),a_i的二阶线性一致椭圆算子。此外,a,b是某些正常数,f*u是由ds定义的卷积。我们确定了非负全局有界解的存在性和唯一性,并且证明了当t→∞时解的渐近性质。我们的主要工具是Banach不动点原理和比较方法。 相似文献
994.
Richard M. Young 《Journal of forecasting》1982,1(2):189-204
The paper outlines the current state of forecasting with an econometric model. After briefly distinguishing econometric techniques from other statistical approaches and arguing the advantages of this approach the paper concentrates on the issue of judgemental adjustments to models for forecasting purposes. Two types of adjustment are distinguished and the conditions under which each is justified are stated. Guidance in the use of adjustment is offered through a review of considerations in an actual forecasting situation. 相似文献
995.
996.
徐松 《北京师范大学学报(自然科学版)》1998,34(4):462-467
考虑结构关系度量误差模型其中P维向量Y,q维向量Z为可观测随机变量,X为不可观测随机变量,U,F分别表示相应的度量误差,H(x,θ)是未知参数θ的非线性函数,参数空间是Rm中的有界闭区间.假设X,U,F相互独立,X服从包括正态分布的一类椭球等高分布,U~N(0,U),F~N(0,F),F>0已知.在一定条件下给出了θ的一个强相合且渐近正态估计. 相似文献
997.
A key statement of the 1965 Monod-Wyman-Changeux (MWC) model for allosteric proteins concerns the distinction between the ligand-binding function (
) and the relevant state function (
). Sequential models predict overlapping behavior of the two functions. In contrast, a straightforward experimental consequence of the MWC model is that for an oligomeric protein the parameters which characterize the two functions should differ significantly. Two situations, where
\bar Y$$
" align="middle" border="0">
and the system ishyper-responsive or where
and the system ishypo-responsive, have been encountered. Indeed, the hyper-responsive pattern was first observed for the enzyme aspartate transcarbamoylase, by comparing
with
monitored by a change in sedimentation. Extensions of the theory to ligand-gated channels led to the suggestion that, on the one hand, hyper-responsive properties also occur with high-affinity mutants. On the other hand, native channels of the acetylcholine neuronal7 receptor and low-affinity mutants of the glycine receptor can be interpreted in terms of the hypo-responsive pattern. For the ligand-gated channels, whereas
is detected directly by ion flux, ligand binding has rarely been measured and the formation of desensitized states may complicate the analysis. However, stochastic models incorporating both binding and channel opening for single molecules predict differences that should be measurable with new experimental approaches, particularly fluorescence correlation spectroscopy. 相似文献
998.
Existing statistical models for network data that are easy to estimate and fit are based on the assumption of dyad independence or conditional dyad independence if the individuals are categorized into subgroups. We discuss how such models might be overparameterized and argue that there is a need for subgrouping methods to find appropriate models. We propose clustering of dyad distributions as such a method and illustrate it by analyzing how cooperative learning methods affect friendship data for school children.Work for this report was initiated while Frank and Komaska visited the Department of Statistics at the University of California, Riverside. Partial support was provided by the Swedish Council for Research in the Humanities and Social Sciences. 相似文献
999.
用广义Pólya罐模型研究随机均匀递归树结点度数的同余类的渐近分布。考虑结点数为n的随机均匀递归树,将树上的结点按其度数关于模m的同余类分成m类,当n趋向无穷时,这m类结点的数目的联合分布渐近正态。 相似文献
1000.
Most change-point models assume that the response is continuous or cross sectional binary. However, in many public health problems, the data is longitudinal binary. There are few studies of change-point problems for longitudinal outcomes. This paper describes a flexible change-point model which includes random-effects and takes into account the difference between various individuals in longitudinal binary data. A transition function is used to make the linear-linear logistic model differentiable at the change-point. The location of the change-point is estimated using the maximum likelihood method. Adjustment of the transition parameter from zero to one controls the sharpness of the transition. The performance of this estimation procedure is illustrated with simulations using SAS/proc nlmixed and a detailed analysis of data relating hormone levels and ovary functions based on data from the Obstetrics and Gynecology Hospital, Medical Center of Fudan University. 相似文献