Theoretical and statistical derivation of a screener for the behavioral assessment of executive functions in children.

The problem of valid measurement of psychological constructs remains an impediment to scientific progress, and the measurement of executive functions is not an exception. This study examined the statistical and theoretical derivation of a behavioral screener for the estimation of executive functions in children from the well-established Behavior Assessment System for Children (BASC). The original national standardization sample of the BASC–Teacher Rating Scales for children ages 6 through 11 was used (N = 2,165). Moderate-to-high internal consistency was obtained within each factor (.80–.89). A panel of experts was used for content validity examination. A confirmatory factor analysis model with 25 items loading on 4 latent factors (behavioral control, emotional control, attentional control, and problem solving) was developed, and its statistical properties were examined. The multidimensional model demonstrated adequate fit, and it was deemed invariant after configural, metric, and scalar measurement invariance tests across sex and age. Given its strong psychometric properties, with further tests of item validity, this instrument promises future clinical and research utility for the screening of executive functions in school-age children. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

The development of risk assessment models for carpal tunnel syndrome: a case-referent study

The present study developed risk assessment models for carpal tunnel syndrome (CTS) which can provide information of the likelihood of developing CTS for an individual having certain personal characteristics and occupational risks. A case-referent study was conducted consisting of two case groups and one referent group: (1) 22 work-related CTS patients (W-CTS), (2) 25 non-work related CTS patients (NW-CTS), and (3) 50 healthy workers (HEALTHY) having had no CTS history. The classification of CTS patients into one of the case groups was determined according to the type of insurance covering their medical costs. Personal characteristics, psychosocial stresses at work, and physical work conditions were surveyed by using a questionnaire tailor-designed to CTS (reliability of each scale ? 0.7). By contrasting the risk information of each case group to that of the referent group, three logistic regression models were developed: W-CTS/HEALTHY, NW-CTS/HEALTHY, and C-CTS/HEALTHY (C-CTS, the combined group of W-CTS and NW-CTS). ROC analysis indicated that the models have satisfactory discriminability (d′ = ;1.91 to 2.51) and high classification accuracy (overall accuracy = 83 – 89%). Both W-CTS/HEALTHY and C-CTS/HEALTHY include personal and physical factors, while NW-CTS/HEALTHY involves only personal factors. This suggests that the injury causation of NW-CTS patients should be attributable mainly to their ‘high’ personal susceptibility to the disorder rather than exposure to adverse work conditions, while that of W-CTS patients be attributable to improper work conditions and CTS-prone personal characteristics in combination.     

Measuring exertion time,duty cycle and hand activity level for industrial tasks using computer vision

Abstract

Two computer vision algorithms were developed to automatically estimate exertion time, duty cycle (DC) and hand activity level (HAL) from videos of workers performing 50 industrial tasks. The average DC difference between manual frame-by-frame analysis and the computer vision DC was ?5.8% for the Decision Tree (DT) algorithm, and 1.4% for the Feature Vector Training (FVT) algorithm. The average HAL difference was 0.5 for the DT algorithm and 0.3 for the FVT algorithm. A sensitivity analysis, conducted to examine the influence that deviations in DC have on HAL, found it remained unaffected when DC error was less than 5%. Thus, a DC error less than 10% will impact HAL less than 0.5 HAL, which is negligible. Automatic computer vision HAL estimates were therefore comparable to manual frame-by-frame estimates.

Practitioner Summary: Computer vision was used to automatically estimate exertion time, duty cycle and hand activity level from videos of workers performing industrial tasks.     

海上钻修机结构裂纹安全性评估

基于BS 7910 2A级评估原理,对某海上钻修机钻井支持模块进行断裂评估。鉴于有限元方法能够大幅提高计算失效评估图评定参数的准确度,采用ANSYS软件子模型技术和奇异单元构造裂纹精细有限元模型,通过节点位移插值计算裂纹尖端应力强度因子,应用路径映射对应力进行线性化求得薄膜应力和弯曲应力,从而完成缺陷构件的失效评估图评定,结果表明：该钻修机钻井支持模块含裂纹构件的评估点位于失效评估曲线内侧,安全因数为1.51,结构能够继续安全服役。所用方法可为含裂纹缺陷的海洋结构物的安全评估提供参考。     

基层设备管理中的专业考核问题

在基层设备管理中,建立以案例考核为主体的考核体系,采用多种激励手段,实现设备管理的有效性和经济性。     

Mass balance soil ingestion estimating methods and their application to inhabitants of rural and wilderness areas: A critical review

Quantitative soil ingestion studies employing a mass balance tracer approach have been used to provide a defensible means to estimate soil ingestion for human health risk assessments. Past studies have focused on soil ingestion in populations living in urban/suburban environments. There is a paucity of reliable quantitative soil ingestion data to support human health risk assessments of other lifestyles that may be predisposed to ingesting soil, such as agricultural workers or indigenous populations following traditional lifestyles. The results of a preliminary analysis of sampling and analytical variability that would result from assessing activities typical of populations in rural or wilderness areas and conducted over wide areas show that approximately 225 subject days would be required to detect a difference of 20 mg/d in soil ingestion. Given the typically small populations in these areas, future soil ingestion studies should be focused on specific activities with a high potential for soil ingestion.     

基于动态安全域的电力系统安全概率评估模型

针对电力系统安全性问题特性,提出一种基于动态安全域的安全概率评估模型。模型核心是不安全概率指标,并通过该指标来表征各电力元件以及整个电力系统的安全性状况。概率方法的引入,使得模型不仅计及系统中各种主要的不确定性因素,而且对系统的安全状况进行了定量的描述。动态安全域理论大大降低了安全概率评估的计算量,使得该模型具有实用性。评估结果可以用于指导运行人员在安全控制中制定正确的决策。用新英格兰10机39节点系统(New England 10-generator 39-bussystem)对该模型做了验证。     

两种紫外成像参数在绝缘子故障诊断中的比较

绝缘子的运行状态直接关系到高压电网的稳定性,在运行过程中会出现绝缘性能下降同时伴随着表面放电,可以用紫外成像仪对其运行状态进行检测。目前,主要的参数是"紫外光斑面积"和"光斑直径",为了对它们在绝缘子故障诊断中的性能有一个对比,笔者通过喷水分级法在现场选择了正常、良好、微痕、劣化和严重老化5种绝缘状态的同一种绝缘子,在实验室搭建平台,在加压8、10、15 kV的情况下,通过南非CoroCAM504紫外成像仪对绝缘子放电情况拍摄足够的紫外图片,运用数字图像处理算法提取了两个参数值,通过MATLAB数字仿真,得到了这两种参数随绝缘状态的变化趋势。结果表明:①在绝缘子绝缘状态艮好的时候,光斑面积和光斑直径几乎可以忽略,对应性比较好,反之,在这两个参数都很小的时候,说明绝缘子绝缘良好;②在绝缘子绝缘出现问题时,二者都有上升趋势,但是光斑面积有一个转折点"4",而光斑直径没有,这说明,当绝缘劣化到一定程度时,光斑面积就没有太大区分度了,而光斑直径则可以区分。最终为绝缘子的运行状态的评估提供了量化的依据和一定的指导。     

改进的集对分析水质综合评价方法

针对标准集对分析存在的同异反评语细化问题,利用原创联系度可展性对其进行改进,并建立了地表水水质评价模型,可以得到评价样本对于各水质评价等级的优劣趋同程度。并与模糊评价相结合应用于山西省地表水质评价,并引入差异系数来优化评价指标体系,利用熵权系数法和超标倍数赋权法求得指标的综合权重。将评价结果与灰色聚类法、综合指标法、模糊神经网络法和投影寻踪法的评价结果进行比较,结果表明：改进后的的集对分析评价结果更贴近实际情况,为水环境分析提供了一种更为科学、合理的评价和决策方法,具有良好的应用前景。     

一种应用于输电管理的动态安全控制新方法

提出了一种解决动态安全评估中的动态优化问题的方法。文中首先回顾了在连续时域空间的动态优化问题的描述方法,然后通过离散化．将该问题转换成离散时域空间的静态优化问题。解决该问题的方法可以用于评估保证系统动态和静态安全稳定的预防控制措施的效果。特别是。通过一个合同削减程序,可以评估在解除管制的市场环境下用于考虑安全约束的输电管理双边合同的修正电量。