外语学习策略研究中存在的主要问题及其对策

探讨了当前国内外外语学习策略研究中存在的一些主要问题,包括术语问题、分类问题、效度和信度问题、研究内容问题、研究方法问题和代表性问题,并针对这些问题提出了相应的对策.     

An Asymptotic Analysis of the Logrank Test

Asymptotic expansions for the null distribution of the logrank statistic and its distribution under local proportional hazards alternatives are developed in the case of iid observations. The results, which are derived from the work of Gu (1992) and Taniguchi (1992), are easy to interpret, and provide some theoretical justification for many behavioral characteristics of the logrank test that have been previously observed in simulation studies. We focus primarily upon (i) the inadequacy of the usual normal approximation under treatment group imbalance; and, (ii) the effects of treatment group imbalance on power and sample size calculations. A simple transformation of the logrank statistic is also derived based on results in Konishi (1991) and is found to substantially improve the standard normal approximation to its distribution under the null hypothesis of no survival difference when there is treatment group imbalance. This revised version was published online in July 2006 with corrections to the Cover Date.     

TEM-8人文知识项目试题评析及其反拨效应

本文结合近两年TEM-8实考试题,针对其新增题型(人文知识项目),从必要性、信度、效度与反拨效应等几个方面进行了简要评析.     

对大学英语一份试卷的分析

IntroductionThis analysis first presents the relevant infor-mation about the test paper that the author used inChina in 2003.Then it evaluates the test in the as-pects of content validity,construct validity and re-liability in scoring.For those deficiencies exhibitedby the test,some suggestions are provided on howto improve the test in order to achieve validity,re-liability and practicality.Background informationThe test purpose.This was an achievement testfirmly based on the syllabus and th…     

Enacting the Millennium Development Goals: Political Technologies of Calculation and the Counter-calculation of Poverty in Namibia

Abstract

This paper advances that the Millennium Development Goals (MDGs) act as a governmentality that brings with them assemblages of international and national policies and practices of poverty reduction. These assemblages are characterized by neoliberal rationalities that shape relationships and practices with and of the poor themselves by repositioning and deploying the values and norms of the market as the principal means for the establishment of development aid partnerships. Such rationalities, we argue, are exercised through political technologies that make visible and operable certain governing schemes such as calculative practices. Drawing on extensive interview, policy, programme, and archival documents, the paper advances the argument that the MDGs and the national development plan for Namibia, Vision 2030, shape ideas of poverty reduction through political technologies of calculation and via multi-scale partnership arrangements. These technologies emerge from diverse elements, subsume the shaping of social and political spaces, and have diverse effects on the lives of the poor. Our analysis also highlights an approach to poverty reduction in Namibia, that of BIG, a Basic Income Grant scheme. We view BIG as a potential counter-calculation of poverty, and counter-partnership to poverty reduction efforts, which can develop into a more socially just and sustainable means to reduce poverty and lead to an overturn of contemporary neoliberal assemblages of poverty reduction.     

涡旋压缩机异形封头可靠性设计

为评估异形封头结构在涡旋压缩机运行过程中的可靠性,参考压力容器椭圆形封头设计理论,采用常规设计方 法对封头进行了结构设计和强度校核;基于封头材料性能、结构尺寸等设计参数的分散性,将各参数作为正态分布的基 本变量,对封头结构进行了可靠性设计,并对基本变量分布参数的灵敏度进行分析。计算结果表明,与常规设计方法相 比,可靠性设计在确保结构安全性的前提下,同时保证了设计的经济性;影响封头可靠度的主要因素是材料屈服极限、工 作压力和壁厚。     

众包标注质量控制研究

众包是近年来流行的一种分布式商业模式,采用众包方式获取标注是一种快速廉价获取海量数据标签的有效方式,由于众包平台中普遍存在不认真完成任务的作弊用户,众包标注质量难以保证.为有效提高众包标注准确性,通过学习标注者的可靠性,实现基于标注者的可靠性进行动态任务分配,采用贪婪的预测模型实现对多个标注者提交的标签进行聚集,获得高质量的众包标注结果.实验结果表明,该方法能获得比基准算法更高的标注准确性,有效实现众包标注质量控制.     

深井水平井水平段水力延伸能力评价与分析

对影响水平井水平段延伸能力的因素进行了分析,然后根据钻井液流体力学理论,建立了水平井循环压耗计算模型,分别对水平井总循环压耗和水平段环空压耗进行计算,进而求出了水平井水平段极限延伸长度值;对钻井液密度、钻井泵额定压力、岩屑床高度和钻井液排量对水平段水力延伸能力的影响进行了分析。研究表明,水平段水力延伸能力受钻井液密度、钻井泵额定压力、岩屑床高度和钻井液排量等多个因素共同影响。为了提高深井水平井的延伸能力,应使用较低密度的钻井液;尽量保持较低的岩屑床高度;钻井液排量应尽量小。同时还认识到,深井水平井水力延伸能力主要受到钻井泵额定压力的制约。研发高额定压力的钻井泵,是提高深井水平井水力延伸能力的主要措施。     

钢铁行业运输环节碳减排情景分析与评价研究

我国钢铁行业碳排放量约为全国碳排放总量的15％,而运输耗能约占物流环节总耗能的5／6。实现钢铁行业中运输环节的节能减排,成为实现我国碳排放总量目标的重要环节。研究钢铁行业中运输环节的碳排放总量与不同碳减排途径及其组合在不同情境下的碳减排潜力,提出基于运输环节碳排放影响因素的碳排放总量测量模型、基于不同减排途径的低碳化分析模型及基于不同途径水平的情景仿真模型。与传统的累计模型不同,低碳化分析模型考虑碳减排途径间的相互影响作用,采用累积形式对减排途径组合进行分析与评价。最终以重庆某钢铁集团20万吨船用钢材作为案例进行情景仿真分析与评价,研究表明：在现有的运输条件下,可通过改变车辆运输方式直接实现0．7到3．9个百分点的碳减排;甩挂运输与混合动力系统改造,可作为优先发展技术,减排效果可达到30％;通过情景仿真分析得知,提高减排途径水平,减排效果将进一步增强。     

沙化土地表土粒度特征参数矩法计算研究

本文在对内蒙古境内几个典型沙地边缘区土样进行粒度实验的基础上,借助MATLAB分析软件对每个样品用三次方程式插值和线性插值相结合的方法计算出分析所需的数据,并进行了有关统计分析。通过研究认为,利用不同步长的粒径分段区间计算所得的粒度参数值间存在着差异,并且利用各种插值计算的参数间也存在差异;总体上粒度参数的离散情况与分段步长存在正相关;分段区间数是影响矩法计算结果的主要因素。