一神新型电动轮毂设计

本文对清华－情谊·海得龙ＱＹ·ＨＤＬ—１型电动轮椅车的电动驱动轮毂进行改进设计。新设计的电动轮毂具有体积小的特点，比参考机型的轴向尺寸减少１８％。     

Confocal fluorescence microscopy of leaf cells: an application of Bayesian image analysis

Confocal fluorescence microscopy is a recent and important imaging tool for visualizing three-dimensional specimens without the need for physical sectioning, so that changes in living cells can be studied over time. The application of interest here is a study of the changes in the stomatal guard cells of plant leaves during their opening and closing response sequences. Quantitative estimates of the size and shape of these cells rely on accurate classification (or segmentation) of the images into areas which are parts of cells and areas which are background. This segmentation is complicated in confocal microscopy because the images appear to be 'smudged' or 'dirty'; this degradation is due largely to diffraction and attenuation of the recorded signal caused by the specimen itself. Correcting for this degradation is difficult without knowing the specimen-dependent parameters involved in the degradation process. A fully Bayesian approach is proposed for tackling this problem of blind deconvolution, i.e. of concurrently estimating the degradation parameters while segmenting two-dimensional sections. The end-products are interval estimates of size and shape which acknowledge some of the uncertainty involved in the segmentation. The results are promising, generating credible intervals which are sufficiently narrow to be useful in practice.     

我国家庭规模和结构的转变及其社会与人口效应

本文阐述了目前我国家庭规模和结构的状况与发展趋势．同时对其产生4的原因和所造成的社会与人口效应作了一定的分析．     

城市规模与人力资本技能溢价:集聚效应和选择效应

本文利用2013年中国家庭收入调查(CHIP)的个人样本数据与《中国城市统计年鉴》数据,考察城市规模与异质性劳动力收入和人力资本技能溢价的关系,并结合城市集聚经济理论和空间知识经济理论对其内在影响机制进行剖析与实证检验。结果显示:大城市在集聚效应和选择效应的作用下具有更高的劳动力名义工资和技能溢价水平;考虑不同规模城市的生活成本差异后,补偿效应会部分抵消大城市的工资溢价,对劳动者的实际收入产生消极影响,从而弱化大城市的技能溢价水平。进一步的非线性效应分析发现,城市规模与劳动力名义收入和实际收入分别存在倒U型和正U型关系;通过比较城市规模对不同收入群体技能溢价的差异性影响验证了群分效应的存在。研究结果对于新型城镇化过程中不同规模等级城市人才政策的制定以及技能异质性劳动力的就业选择具有重要的现实意义和参考价值。     

流迁人口对广东省人口发展的替代效应

所谓替代迁移是指迁移人口对长期处于更替生育水平以下的人口,因人口自然减少而产生的替代效用。广东省不但是全国人口流动和迁移最活跃的省份,而且人口总和生育率已连续10年低于更替水平,进入低生育水平时期。本文实证分析广东省在无流动人口、保持峰值人口、维持峰值劳动年龄人口和潜在供养比最大值等条件下,流迁人口对总人口规模和结构的替代效应,认为适度替代流迁人口是解决长期维持低生育水平地区所产生的人口问题的有效途径。     

A Wavelet-Based Approach of Testing for Granger Causality in the Presence of GARCH Effects

The size and power of the most commonly used tests and a new wavelet-based approach of testing for Granger causality is evaluated by means of a Monte Carlo study in which the error term follows a generalized autoregressive conditional heteroscedasticity consistent (GARCH) process. In the simulation study it is shown that the commonly used causality tests tend to overreject the true null hypothesis in the presence of GARCH errors and that the new wavelet-based approach improves the size properties of the Granger causality test for all of the different situations evaluated.     

Assessing Occupational Exposure via the Unbalanced One-Way Random Effects Model

In this article, an unbalanced one-way random effects model is considered for the log-transformed shift-long exposure measurements. Exact test and confidence interval for the proportion of workers whose mean exposure exceeds the occupational exposure limit are developed based on the concepts of generalized p-value and generalized confidence interval. Some simulation results to compare the performance of the proposed test with that of the existing method are reported. The simulation results indicate that the proposed method appears to have significant gain in the size and power.     

上市公司审计费用率影响因素实证研究

本文运用回归分析技术对2002年我国证券市场A股年报审计费用率进行了实证研究。结果表明:影响年报审计费用率的因素有两类,一是上市公司的规模、处于微利区间的净资产收益率和处于保配区间的净资产收益率等直接影响因素,二是反映上市公司某些特征的流动比率、净资产收益率、应收账款在总资产中的比重等间接影响因素;资产负债率则表现为既直接与审计费用率相关,又通过资产规模间接与审计费用率相关;没有发现会计师事务所的规模、存货在总资产的比重对审计费用率的影响。     

测试英语词汇的广度、深度和强度

自98年Laufer两次进行广度结合强度的三层面英语词汇知识研究后,Laufer et al于2004年两次进行了四层面词汇知识研究,首次提出并正在进行词汇广度结合强度的计算机机测的研究工作。在词汇研究领域原有的广度和深度上,又开辟了一条新的道路。文章试讨论80年代以来国内外就测试英语词汇的广度、深度和强度的主要研究,尝试探讨这些研究对我们英语词汇测试研究与词汇学习的启示。     

不同等级富士苹果价格差别分析

本文是对我国华北、华东、华中等苹果主产区进行实地调查分析结果的一部分。反映了我国苹果产区富士苹果的价格变动和等级差价情况 ,对价格差别形成的主要原因做了初步分析 ,并提出了制止苹果价格下跌的相应对策