教学型恒压变频供水系统的研制

教学设备与实际生产设备相比 ,要求具有体积小、造价低、直观透明 ,技术领先的特点 ,从用途到制造工艺均具有其特殊性 ,须专门研究和开发。本文论述我们研制的具有网络功能的微型恒压供水系统的研制过程和使用情况。     

普希金与贡斯当

关于普希金自由思想与贡斯当的关系是一个目前极少论及的问题。贡斯当对普希金的影响有两条途径:直接途径即普希金对贡斯当以及斯达尔夫人著作的直接阅读,间接途径即通过以恰达耶夫为代表的中介作用领会贡斯当的自由思想。普希金与贡斯当在宪政思想和对极权的批判方面达成共鸣,因之,他的自由思想"独立于时代的政治仇恨",而与现代自由理念发生关联。     

构建好社会的方略及我国建国方略的转变

构建好社会有两种不同的方略 :一种是先预设一套固定模式再实施的“理想蓝图法” ;另一种则是没有任何不变规定的“不断改错法”。鉴于两种方略各有利弊 ,需要再提出一种新的方略 ,这就是综合了前两种方略优点的“终极价值目标法”。我国第一代领导人时期一直是用理想蓝图法的思路建国 ,这种状况到第二代领导人时才出现根本转变 ,尤其是邓小平“三个有利于”的提出 ,标志我们已开始走向终极价值目标法的思路。     

A theory of statistical models for Monte Carlo integration

Summary. The task of estimating an integral by Monte Carlo methods is formulated as a statistical model using simulated observations as data. The difficulty in this exercise is that we ordinarily have at our disposal all of the information required to compute integrals exactly by calculus or numerical integration, but we choose to ignore some of the information for simplicity or computational feasibility. Our proposal is to use a semiparametric statistical model that makes explicit what information is ignored and what information is retained. The parameter space in this model is a set of measures on the sample space, which is ordinarily an infinite dimensional object. None-the-less, from simulated data the base-line measure can be estimated by maximum likelihood, and the required integrals computed by a simple formula previously derived by Vardi and by Lindsay in a closely related model for biased sampling. The same formula was also suggested by Geyer and by Meng and Wong using entirely different arguments. By contrast with Geyer's retrospective likelihood, a correct estimate of simulation error is available directly from the Fisher information. The principal advantage of the semiparametric model is that variance reduction techniques are associated with submodels in which the maximum likelihood estimator in the submodel may have substantially smaller variance than the traditional estimator. The method is applicable to Markov chain and more general Monte Carlo sampling schemes with multiple samplers.     

从农业文明特征看中国传统建筑的设计意念

农业社会生活是中国传统社会的物质文化、制度文化和观念文化创造、发展的基础。农业文明深刻影响中国传统文化民族性格、心理及社会结构特征,进而影响着中国建筑的设计理念,从而产生并发展出源远流长而丰富深刻的建筑美学思想。从华夏民族重实际轻玄想的务实精神、师法自然、恒久变易、封闭、保守的围合心态,及家国同构的社会结构特征,论述中国传统建筑迥异于西方建筑的以人为本、因任自然、反本开新、重重包围、院院相套及门、堂分立的设计意念。     

Local Linear Estimation for Time-Dependent Coefficients in Cox's Regression Models

This article develops a local partial likelihood technique to estimate the time-dependent coefficients in Cox's regression model. The basic idea is a simple extension of the local linear fitting technique used in the scatterplot smoothing. The coefficients are estimated locally based on the partial likelihood in a window around each time point. Multiple time-dependent covariates are incorporated in the local partial likelihood procedure. The procedure is useful as a diagnostic tool and can be used in uncovering time-dependencies or departure from the proportional hazards model. The programming involved in the local partial likelihood estimation is relatively simple and it can be modified with few efforts from the existing programs for the proportional hazards model. The asymptotic properties of the resulting estimator are established and compared with those from the local constant fitting. A consistent estimator of the asymptotic variance is also proposed. The approach is illustrated by a real data set from the study of gastric cancer patients and a simulation study is also presented.     

《逻辑哲学论》的逻辑观

维特根斯坦在《逻辑哲学论》中所提出的逻辑命题是重言、是形式的观点，对于本世纪哲学家们的逻辑观给予了决定性的影响。本文对《逻辑哲学论》的逻辑观、它的基本的理论假定、理论背景及影响作了探讨，并就它的评价问题阐明了个人的意见     

MINIMAX ESTIMATION OF A MULTIVARIATE NORMAL MEAN UNDER A CONVEX LOSS FUNCTION

Let X = (X₁, - X_p)prime; ˜ N_p (μ, Σ) where μ= (μ₁, -, μ_p)' and Σ= diag (Σ²₁, -, Σ²_p) are both unknown and p3. Let (n_i - 2) w_i/Σ²_i! X²_ni, independent. of w_i (I ≠ j = 1, -, p). Assume that (w₁, -, w_p) and X are independent. Define W = diag (w₁, -, w_p) and ¶ X ¶²_w= X'W^-1Q^-1W^-1X where Q = diag (q₁, -,n q_p), q_i > 0, i = 1, -, p. In this paper, the minimax estimator of Berger & Bock (1976), given by δ (X, W) = [I_p - r(X, W) ¶ X ¶^-2_w Q^-1W^-1] X, is shown to be minimax relative to the convex loss (δ - μ)'[αQ + (1 - α) Σ^-1] δ - μ)/C, where C =α tr (Σ) + (1 - α)p and 0 α 1, under certain conditions on r(X, W). This generalizes the above mentioned result of Berger & Bock.     

关于Ricci对称的黎曼流形的孤立性

使用P.Li的Sobolev不等式和Lp估计方法，研究Ricci对称的黎曼流形的量子化现象．证明了对于紧致的具有正数量曲率的Ricci对称的黎曼流形M，存在一个常数A，当M的保圆曲率张量的La/2模小于A时，M为常曲率空间．     

Skewness and mixtures of normal distributions

The effect of skewness on hypothesis tests for the existence of a mixture of univariate and bivariate normal distributions is examined through a Monte Carlo study. A likelihood ratio test based on results of the simultaneous estimation of skewness parameters, derived from power transformations, with mixture parameters is proposed. This procedure detects the difference between inherent distributional skewness and the apparent skewness which is a manifestation of the mixture of several distributions. The properties of this test are explored through a simulation study.