用求荷载控制段的方法确定临界荷载

提出在移动荷载组作用下求简支梁内某一指定截面的最大弯矩的一种解法，这种解法的关键是求出梁上各个荷载的控制段．     

PITMAN-CLOSENESS AS A MEASURE TO EVALUATE THE QUALITY OF FORECASTS

ABSTRACT

We consider Pitman-closeness to evaluate the performance of univariate and multivariate forecasting methods. Optimal weights for the combination of forecasts are calculated with respect to this criterion. These weights depend on the assumption of the distribution of the individual forecasts errors. In the normal case they are identical with the optimal weights with respect to the MSE-criterion (univariate case) and with the optimal weights with respect to the MMSE-criterion (multivariate case). Further, we present a simple example to show how the different combination techniques perform. There we can see how much the optimal multivariate combination can outperform different other combinations. In practice, we can find multivariate forecasts e.g., in econometrics. There is often the situation that forecast institutes estimate several economic variables.     

Bayesian Forecasting With Stable Seasonal Patterns

A multiplicative seasonal forecasting model for cumulative events in which, conditional on end- of-season totals being given and seasonal shape being known, it is shown that events occurring within the season are multinomially distributed is presented. The model uses the information contained in the arrival of new events to obtain a posterior distribution for end-of-season totals. Bayesian forecasts are obtained recursively in two stages: first, by predicting the expected number and variance of event counts in future intervals within the remaining season, and then by predicting revised means and variances for end-of-season totals based on the most recent forecast error.     

Optimal Binary Prediction for Group Decision Making

We address the problem of optimally forecasting a binary variable for a heterogeneous group of decision makers facing various (binary) decision problems that are tied together only by the unknown outcome. A typical example is a weather forecaster who needs to estimate the probability of rain tomorrow and then report it to the public. Given a conditional probability model for the outcome of interest (e.g., logit or probit), we introduce the idea of maximum welfare estimation and derive conditions under which traditional estimators, such as maximum likelihood or (nonlinear) least squares, are asymptotically socially optimal even when the underlying model is misspecified.     

英汉词义的对比及翻译方法探究

语言翻译的过程不仅是简单的语言转换,更是两种思维方式和观念系统的相互作用及深化的过程。本文通过英汉词汇意义的构成、词义差别的对比,分析了两种语言之间产生差异的原因,并介绍了常见的翻译方法。     

网络环境中自然阅读过程词汇附带习得可行性研究

此研究基于戴炜栋等的网络环境下的词汇习得认知心理环境框架和Pmvio提出的双码理论,从Laufer和Hulstijn的可以将词汇附带习得进行量化的投入量假设出发,结合网络环境下阅读特点,采用定量和定性研究方法,验证网络环境自然阅读中词汇附带习得的可行性。结果表明：在网络环境下,投入量大的阅读任务比投入量小的阅读任务更能促进词汇附带习得;“投入量”指数大的阅读任务对学习者词汇知识的保持效果更好。     

浅谈UPS的使用与维护

UPS意为“不间断供电电源”,对保护负载设备有重要作用。使用和维护UPS时,要根据负载合理选用UPS类型;UPS不宜长期处于满载或过度轻载状态下运行;要正确使用和维护UPS系统内的蓄电池;做好UPS电源线和通信线的防雷过压保护;要在UPS电源前科学加装交流稳压器;要定期对UPS进行检查和放电。     

未焊透缺陷安全尺寸的评价研究

未焊透是压力管道焊接接头常见缺陷之一,严重时会导致管道的承载能力明显降低,进而引发严重的安全事故。 目前我国的《在用工业管道定期检验规程》中对未焊透管道的定级是很保守的,为了减少对未焊透缺陷的返修,文章采 用非线性有限元分析的方法,通过简化未焊透管道的影响因素,并研究在不同载荷工况下管道失效模式与缺陷尺寸的关 系,获得了未焊透管道的极限载荷曲线簇;再运用塑性力学分析方法对有限元分析结果进行筛选,得到了焊接缺陷的安 全尺寸;最终通过试验验证极限载荷数值分析结果的合理性。研究结果表明含有超标焊接缺陷（如未焊透）的管道不通 过复杂应力计算和安全评定即可在保证安全前提下最大限度地使用。     

昆明话和普通话"VV"、"V(一)下"的功能、形式对比

与其他西南官话相比,昆明方言最突出的特点之—就是具有动词重叠式,形成了"VV"与"V一下"表示短暂、尝试意义两种形式共存的局面。表面看,这两种形式及其表意功能与普通话是一致的,但如果着眼于二者在各自语言系统中与相关形式的依存关系,却存在较大差异。通过与各种相关形式的对比分析,可以分析出昆明话这两种形式与普通话的系统差异以及结合历史来源探讨两种形式间的依存关系,从而在此基础上进行语言形式和功能的对比研究。     

模糊决策控制的动态经济调度方法

本文基于模糊数学的基本原理与负荷预报相结合,提出了一种计及辅助设备控制的动态经济调度方法。该方法利用模糊决策的理论对与辅助设备相对应的运行区域的启停和转换做出经济而可行的判断。把发电与负荷的平衡、费用消耗、区域运行时间及旋转备用看成相应的模糊子集,从而建立其相应隶属函数。通过算例的试算证明是可行的。