关于如何完善本科成绩核查系统的探讨

目前本科成绩核查系统存在很多缺陷,要不断在各个方面进行进一步完善,避免错登、漏登等情况发生,提高成绩核查的准确性.     

Unraveling the Source of African American Children's Positively Biased Perceptions of Peer Acceptance

The present study investigated possible ethnic contributions to overly positive self‐perceptions in middle childhood. The goals of this study were threefold. First, the present study sought to replicate the intriguing findings reported by Zakriski and Coie that African American children overestimate their acceptance, and European American children underestimate acceptance by other‐ethnicity peers. Second, this study examined possible explanations for ethnic differences in the pattern of perceptual bias. Finally, this study extended prior research by examining ethnic differences in the accuracy of children's perceived peer acceptance. Archival data consisting of 826 children in third (N = 284), fourth (N = 241), and fifth grades (N = 301) were used in the present investigation; 237 of which were African American children, and 589 were European American children. Results of this study replicated the findings of Zakriski and Coie . Moreover, African Americans' overestimation and European Americans' underestimation of acceptance by other‐ethnicity peers was found to be attributable to more positive views of self and others among African American children relative to European American children. Finally, children were found to be more accurate about judging their acceptance by peers of the same ethnicity than those of a different ethnicity. Possible explanations of what causes African American children to have more positive views of self and others than European American children are discussed.     

On the relative performance of the block bootstrap for dependent data

In the independent setting, both Efron's bootstrap and “empiricai Edgeworth expansion” (E.E-expansion) give second-order accurate approximations to distributions of standardized and studentized statistics in the smooth function model. As a result, Efron's bootstrap was often regarded as roughly equivalent to the one-term E.E-expansion. However, a more detailed analysis shows that Efron's bootstrap outperforms the E.E-expansion in terms of loss functions by Bhattacharya and Qumsiyeh (1989) and in terms of probabilities for large deviations by Hall (1990) and Jing et a1 (1994). in this paper, we shall study the performances of the block bootstrap and the E.E-expansion for the weakly dependent data. It turns out that similar properties hold:both perform equally well at the center of the distribution but the block bootstrap provides accurate approximations even in the tails of the distributions. The study is focued on the simple case of standardized and studentized sample mean, but the conclusions can be easily extended to the smooth function of multivariate means.     

Empathic Accuracy and Aggression in Couples: Individual and Dyadic Links

The authors examined links between intimate partner aggression and empathic accuracy—how accurately partners can read one another's emotions—during highly affective moments from couples' (N = 109) video recall of laboratory‐based discussions of upsetting events. Less empathic accuracy between partners was generally related to higher levels of aggression by both partners. More specific patterns emerged based on the type of aggression and emotion being expressed. Women's poorer ability to read their partners' vulnerable and positive emotions was linked to both men's and women's greater physical and psychological aggression. Moreover, women's inaccuracy in reading their partner's hostility was linked to women's greater psychological aggression toward the men. Men's inaccuracy in reading their partner's hostility was linked to women's (not men's) greater physical and psychological aggression. The results suggest important nuances in the links between empathic inaccuracy and aggression, and implications for prevention and treatment of partner aggression are discussed.     

Validation of qualitative microbiological test methods

This paper considers a statistical model for the detection mechanism of qualitative microbiological test methods with a parameter for the detection proportion (the probability to detect a single organism) and a parameter for the false positive rate. It is demonstrated that the detection proportion and the bacterial density cannot be estimated separately, not even in a multiple dilution experiment. Only the product can be estimated, changing the interpretation of the most probable number estimator. The asymptotic power of the likelihood ratio statistic for comparing an alternative method with the compendial method, is optimal for a single dilution experiment. The bacterial density should either be close to two CFUs per test unit or equal to zero, depending on differences in the model parameters between the two test methods. The proposed strategy for method validation is to use these two dilutions and test for differences in the two model parameters, addressing the validation parameters specificity and accuracy. Robustness of these two parameters might still be required, but all other validation parameters can be omitted. A confidence interval‐based approach for the ratio of the detection proportions for the two methods is recommended, since it is most informative and close to the power of the likelihood ratio test. Copyright © 2014 John Wiley & Sons, Ltd.     

Reflections on Accuracy

The difference between test accuracy and predictive accuracy is presented and defined. The failure to distinguish between these two types of measures is shown to have led to a misguided debate over the interpretation of prevalence estimates. The distinction between test accuracy defined as sensitivity and specificity, and predictive accuracy defined as positive and negative predictive value is shown to reflect the choice of the denominator used to calculate true positive, false positive, false negative, and true negative rates. It is further shown that any instrument will tend to overestimate prevalence in low base rate populations and underestimate it in those populations where prevalence is high. The implications of these observations are then discussed in terms of the need to define diagnostic thresholds that have clinical and policy relevance.     

英语学习者朗读错误对比分析

不同水平的英语学习者在朗读中的各类错误方面存在差异。高水平组在准确性错误中的增减音、重音误置、错词方面显著少于低水平组;而在流利性错误中的重复、修补、不当停顿方面,两组之间无显著差异。高水平组中,只有错音和修补有显著区别;低水平组中,只有重音误置和修补、加减词和错音有显著区别。     

基于步进电机控制的伺服钻孔机设计

采用高性能的STC89C516RD+单片机,控制步进电机完成点动、快进、工进以及精确定位的任务。定位系统是通过设定原点和精确控制脉冲数来实现的。解决了钻头在刚性材料表面上不能精确定位以及金属屑不易排出去的难题。与传统的手动钻孔机相比,该伺服钻孔机控制方便、精度高、生产效率高。     

Undercounting Medicaid Enrollment in Maryland: Testing the Accuracy of the Current Population Survey

The U.S. Census Bureau’s Current Population Survey is the most commonly cited source for estimates of the insurance status of Americans, but there are concerns that the data may undercount participation in public programs such as Medicaid. Such a Medicaid undercount may result from survey respondents not acknowledging Medicaid coverage because they are unaware that they are enrolled in Medicaid, because they have not recently received health services, due to the stigma associated with receiving public assistance programs, or due to simple recall bias. This paper estimates the extent to which the Current Population Survey undercounts Medicaid participation in a single mid-Atlantic state, Maryland. We administered the Current Population Survey questionnaire to a random selection of known Medicaid participants. We find evidence that the Current Population Survey significantly undercounts Medicaid participation in Maryland and that much of the undercount could be corrected if the survey better identified the Maryland Medicaid program. We also find that recall bias may contribute to the undercount as well. There was no indication that stigma contributed to any undercount. Though not an aim of this study, we find that the Medicaid undercount may contribute to an over count of the number of uninsured.

江浦县1:5万30m空间分辨率DEM的制作

本文主要介绍了建立在G IS软件的基础上,以江浦县为例,利用1:5万的国家基本地形图作为基础底图资料,根据国家DEM的制作精度要求,制作1:5万、30m空间分辨率数字高程模型(DEM)的方法及过程。同时对生成的DEM做了精度和质量上的检验。