多元线性模型中系数矩阵的Minimax可容许估计

对于多元线性模型Y=XΘ+ε,E(ε)=0,COV(ε)=σ2(△)(◎)Σ,在该模型中,Θ是未知参数矩阵,此处选取的损失函数是矩阵损失,在齐次线性估计类L={AY:A是k×n的常数矩阵}中给出了多元回归系数矩阵的可估函数SΘ的Minimax容许估计,并且证明了其唯一性.     

相对效率与广义相关系数

对于线性模型y=Xβ+ε,E(ε)=0,cov(ε)=V>0,在错误地把协方差阵取为cov(ε)=D>0的条件下,对于一种新的相对效率,本文研究了它与某些广义相关系数的关系.     

回归系数的一种有偏估计

在线性回归模型Y=Xβ ε;E(ε)=0;Cov(ε)=σ2V,V＞0下,给出了一种新的有偏估计(β)(F(K))=(X′V-1X TF(K)T′)-1X′V-1Y,讨论了这种有偏估计的优良性,推广了已有的相关结果.     

二阶拟线性常微分方程组边值问题的奇摄动

本文研究二阶拟线性常微分方程组边值问题εy″+A(t,y,ε)y′十g(t,y,ε)=0y(0,ε)=α(ε),y(1,ε)=β(ε)其中ε>0是小参数,y,g,α,β是n维向量函数,A是n×n矩阵函数。假设退化问题A(t,y,0)y′+g(t,y,0)=0,y(1)=β(0)有解y_0(t),则加上一些其他条件后,便可推知当ε>0充分小时,存在摄动问题的解y(t,ε),它和它的导函数可表为y(t,ε)=sum from i=0 to m(y_i(t)ε~i十O(ε~(m+1))+O(e~(-μi/ε))y′(t,ε)=sum from i=0 to m(y_i′(t)ε~i十O(ε~(m+1))+O(ε~(-1)e~(-μi/ε))其中y_1(t),…,y_m(t)可依次由具有递推形式的一阶常微分方程组的终值问题解出。     

球形脉冲波在焦点的散射研究(Ⅱ)

本文讨论了半线性波动方程(2t-Δx)uε+F(εα|tuε|p-1tuε)=0(t,x)∈[0,∞[×R3uε|t=0=εU0(r,r-εr0),tuε|t=0=Ul(r,r-εr0)。当p>2,α=p-2时解在到达焦点(r0,0)前无穷远处的性态,其中F在R上是一致Lipschitz的。通过变量变换,将问题转化为负无穷远处的初、边值问题,证明解的存在唯一性,引入线性解讨论脉冲波在t→-∞的传播性态,并引入散射算子说明了脉冲波越过焦点的过程。     

线性回归模型的一种有偏估计

在线性回归模型Y=Xβ ε;Ε(ε)=0;cov(ε)=σ2I下给出了有偏估计βc*(K)=(cXTX ΦKΦT)-1XTY,其中c≥1,K=diag(k1,k2,…,kn)为对角阵,ki≥0,讨论了这种有偏估计的可容许性,利用Stein式压缩技术说明在均方误差意义下它优于广义岭估计,推广了有关结果.     

具有转向点的奇摄动非线性Robin问题

本文利用边界层校正法研究了在右端点具有转向点的二阶非线性方程的奇摄动Robin问题εy'=f(x,y,y',ε),-10是小参数,p>0。在适当的假设下,利用微分不等式作者证明了此Robin问题解的存在性,并得到了其一致有效渐近展式。     

带有不完全椭球约束的多元回归系数线性估计的泛容许性

 对于带有不完全椭球约束的多指标线性模型Y=XΘ+ε,ε～(0,∑ V),Θ′X′NXΘ≤∑,给出了SΘ的泛容许估计的定义,并在齐次线性估计类(非齐次线性估计类)中给出了SΘ的估计AY(AY+C)泛容许的充要条件,不论SΘ是否可估.     

一类拟线性抛物方程组的整体吸引子与误差估计

研究一类拟线性抛物方程组tu(x,t)=Aεu-f(x,ε-1x,t,u(x,t))的整体吸引子Aε和对应均匀化方程组的整体吸引子A0,并给出了Aε和A0在Hausdorff距离下的误差估计.     

一类带有两个参数变号四阶多点边值问题的正解

应用拓扑度理论及下解的方法,讨论了以下带有两个参数的四阶多点边值问题u(4)(t)+βu′′(t)-αu(t)=μh(t)f(t,u(t),u′′(t)),0相似文献   

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Jane Eyre——A Feminist In The 19th Century

In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-