对气测录井烃组分三角形图解法的研究

气测录井是通过分析钻井液中石油和天然气中的烃类气体、氢气、二氧化碳气体来发现和评价油气层的技术.三角形图解法是评价油气层的方法之一,本文用数学分析的方法得出了与三角形图解法相关的关系式,将繁琐、不精确的做图法换成简单的运算,不仅改进了工作方法,而且极大地提高了精度.     

不同年级学生阅读示意图课文的眼动实验研究

本研究采用眼动方法，对85名小五、初二和高二年级学生图文阅读的阅读理解指标和眼动指标进行考察，结果表明：1）不同年级学生的阅读能力一般都具有明显的年龄发展特征，其中从小五到初二是示意图不同难度课文阅读理解指标和易课文眼动指标发展的一个重要时期；2）不同年龄级学生阅读不同呈现方式课文的阅读理解指标和眼动指标，示意图课文一般显著优于无图课文，图对课文的阅读理解具有明显的促进作用；3）不同年龄级学生阅读不同难度课文的阅读理解指标和眼动指标，易课文一般也显著优于难课文。     

数学建模教学对学生能力的培养

数学建模方法是一种极其重要的思想方法，它是把实际问题抽象成数学语言符号，构建数学模型，从而解决实际问题，通过几个实际问题的解决说明数学建模对学生能力的培养作用．     

Maxwell's role in turning the concept of model into the methodology of modeling

This is a contribution towards a history and philosophy of modeling in its early stages in electromagnetism. In 1873, James Clerk Maxwell (1831–1879) hinted at the methodology of modeling at the end of his Treatise on Electricity and Magnetism. We focus on Maxwell's impact on physicists who immediately followed him, specifically Oliver Lodge (1851–1940) and George Francis FitzGerald (1851–1901). We begin with the role that the scientific concept of model played in the late nineteenth century, as assessed by Ludwig Boltzmann (1844–1906). We then discuss the role of hypothesis as a methodology, the appeal to (dynamical) illustration, and the way Maxwell applied model and working model in his studies of electromagnetism. We show that for Maxwell these key terms were kept distinct, but Lodge did not maintain these distinctions and, in this regard, FitzGerald followed Lodge. Notwithstanding Lodge's influence, Fitzgerald modified Maxwell's theory based on the mechanical model he designed, thereby implicitly taking the first step towards modeling. This methodology consists in drawing consequences from the (mechanical) model to the (electrodynamic) theory and modifying the latter in light of the functioning of the former. At the core of our argument is the thesis that it was a methodological novelty to move from the concept of model to the methodology of modeling. The introduction of modeling as a new methodology into physics in the late nineteenth century was a major event which deserves proper recognition.     

民主的悖论--对法国福利制度的思考

法国是一个高福利的国家,高福利制度为法国人民提供了保障,但也有不少弊病.它造成产品的高成本和国际竞争力的降低,从而使法国经济陷于长期的不景气状态,并且出现了高失业率.同时,福利经费也赤字累累,难以为继.但在法国现行的政治体制下,高福利制度难以进行根本的改革,消除它的弊端,这是我们必须引以为鉴的.     

平均分排序法合理性分析

依 A rrow提出的选举问题的四条公理为准则 ,利用联合尺度条件 ,阐明目前流行的筛选平均分排序法 (即去掉一个最高分和一个最低分后 ,用余下的各分数的算术平均分作为待评人的最后得分 )是一种看似公正 ,实为错误的排序方法     

当前大学生心理矛盾的思考和对策

本文分析了大学生心理矛盾产生的原因,进一步从内在因素和外在社会环境两个方面阐述了大学生心理矛盾的特点,有针对性地从教育制度、教育形式和思想政治教育方法上提出了解决当前大学生心理矛盾的对策和方法。     

论数码技术对插图艺术的影响

数码技术的普及,使插图获得了新的、独特的视觉冲击力和艺术内涵,导致插图设计风格的变化,改变了插图的美学观念与审美方式,给传统插图艺术注入了新的活力。     

标志设计与品牌形象

从标志设计发展趋势的角度，阐述了标志设计伴随时代的发展而更新的重要性，尤其是标志设计在创造品牌形象时的重要作用。     

Identification of asymmetric prediction intervals through causal forces

When causal forces are specified, the expected direction of the trend can be compared with the trend based on extrapolation. Series in which the expected trend conflicts with the extrapolated trend are called contrary series. We hypothesized that contrary series would have asymmetric forecast errors, with larger errors in the direction of the expected trend. Using annual series that contained minimal information about causality, we examined 671 contrary forecasts. As expected, most (81%) of the errors were in the direction of the causal forces. Also as expected, the asymmetries were more likely for longer forecast horizons; for six‐year‐ahead forecasts, 89% of the forecasts were in the expected direction. The asymmetries were often substantial. Contrary series should be flagged and treated separately when prediction intervals are estimated, perhaps by shifting the interval in the direction of the causal forces. Copyright © 2001 John Wiley & Sons, Ltd.