分光光度法测定多元酸离解常数的优化计算法

本文讨论了依据优化计算原理用分光光度数据计算多元酸离解常数的优化方法和计算机程序,用编制的计算机程序计算了多种多元酸的离解常数,所得结果与文献值相符。     

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。     

电动自行车调速控制电路的改进

通过对某种调速控制器的剖析及试验,找出了原控制器使用过程中频繁烧坏功率场效应管的原因,斫制出了一 种改进型控制器电路,从根本上解决了原电路存在的问题。文章阐述了改进型电路的设计方法,并给出了电路原理图。     

用Visual Basic设计虚拟PLC软件界面

在使用Visual Basic 6.0开发可编程控制器虚拟软件的过程中,设计软件界面时采用了几种方法,取得了良好的效果。对这些方法的作用、优点和注意事项进行了阐述,并提出了一些可以考虑的其它方法或建议。     

计算机实时模糊控制一级倒立摆装置

本文通过分析模糊控制中语言控制规则的特点,提出了一种新的带修正因子的控制规则自调整方法,实时控制一级倒立摆装置的实验表明,这种设计方法是简单而且有效的。     

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.