A Lower Bound for the Wrap-around L2-discrepancy on Combined Designs of Mixed Two- and Three-level Factorials

The objective of this article is to study the issue of employing the uniformity criterion measured by wrap-around L₂-discrepancy to assess the optimal foldover plans. For mixed two- and three-level fractional factorials as the original designs, general foldover plan and combined design under a foldover plan are defined, and the equivalence between any foldover plan and its complementary foldover plan is investigated. A lower bound of wrap-around L₂-discrepancy of combined designs under a general foldover plan is obtained, which can be used as a benchmark for searching optimal foldover plans. Moreover, it also provides a theoretical justification for optimal foldover plans in terms of uniformity criterion.     

中国情境下中层管理者的适应性绩效因素研究

随着我国经济的快速发展和外部竞争的加剧,出现了组织扁平化、企业内外部变化加快和职业高原等新情形,既给中层管理者带来了新困境,也对其适应性提出了新挑战。以Plukos八维度适应性绩效模型为基础,立足国内情景,运用改进型DEMATEL方法对适应性绩效影响因素进行定量分析,得出影响中层管理者适应性绩效的关键因素,并对各因素重要性进行了排序和分析。     

基于突变理论的铀矿山循环经济发展水平评价

铀矿山循环经济发展是铀矿开采的必然选择,铀矿山循环经济发展水平评价是检验和预测循环经济发展状态的判断依据。基于突变理论的改进的突变评价方法,构建了铀矿山循环经济发展水平的评价指标体系,并选取我国核工业某矿冶局所属的5个铀矿山作了铀矿山循环经济发展水平评价的实证分析。实证分析表明了该方法的可行性、有效性和可靠性。这对于铀矿企业处理资源有效利用和环境保护问题,实现经济效益和社会效益协调统一具有理论和现实意义。     

An Exposure Assessment of Methyl Mercury via Fish Consumption for the Japanese Population

The objective of this article was to propose an exposure assessment model to describe the relationship between fish consumption and body methyl mercury (MeHg) levels in the Japanese population. Individual MeHg intake was estimated by the summation of species-specific fish consumption multiplied by species-specific fish MeHg levels. The distribution of fish consumed by individuals and the MeHg level in each fish species were assigned based on published data from Japanese government institutions. The probability of MeHg intake for a population was accomplished through a Monte Carlo simulation by the random sampling of fish consumption and species-specific MeHg levels. Internal body MeHg levels in blood and hair were estimated using a one-compartment model. Overall, the mean value of MeHg intake for the Japanese population was estimated to be 6.76 μg/day or 0.14 μg/kg body weight per day (bw/day), while the mean value for the hair mercury level was 2.02 μg/g. Compared with the survey data that tabulated hair mercury levels in a cross-section of the Japanese population, the simulation results matched the hair mercury survey data very well for women, but somewhat underestimated for men and all of the population. This exposure assessment model is a useful attempt at further risk assessment with respect to a risk-benefit analysis.     

建设工程项目筹资结构优化

工程项目建设 ,必须要有足够的资金支持 ,面对庞大的资金需求 ,可以从资本市场上寻求投资资金 ,因而如何使筹资结构优化便成为一个重要问题。从筹资方式选择入手 ,分析几种常见筹资手段的特点 ,从中寻求最优筹资结构组合 ,力求避免目前筹资结构单一 ,筹资决策盲目性等问题     

中印产业内贸易发展水平的指数分析

通过对1993—2009年中印产业内贸易指数的测算,分析中印产业内贸易的发展演变过程和水平,并根据中印两国贸易不平衡的实际情况计算了调整后的产业内贸易指数,从而得出简要的研究结论。     

安徽省县级科技型企业发展存在问题及对策研究

县级科技型企业的发展受到来自国家及社会的高度关注,这些企业在产业发展、科技进步、产业升级、增加居民收入等方面起着至关重要的作用。县级科技型企业由于规模小、资源有限,发展的速度相对缓慢。文章通过对安徽省县级科技型企业发展的特点分析,找出其中存在的问题,并针对这些问题提出了＂建设产业园区,促进配套产业发展＂、＂建立健全人才培养机制,加强人才队伍建设＂、＂加大招商引资力度,优化信贷环境＂、＂引进先进管理理念,打造自有名牌＂、＂明确政府责任,营造良好投资环境＂等加快县级科技型企业发展对策。     

区域性学业水平测试质量分析——小学数学学业水平检测试卷与课程标准一致性的视角

区域性学业水平测试是地方教育行政部门监测教育质量的重要方法。因此,分析区域性学业水平测试质量就显得十分重要。为此,借鉴韦伯一致性分析模式,对某地区小学数学学业水平检测试卷的质量进行了尝试探究,即从学习领域和年级两个方面分析了区域性小学数学学业水平测试与课程标准的一致性水平状况及特征。同时,还从数与代数、空间与图形、统计与概率、实践与综合应用等学习领域和知识种类、知识深度、知识广度和知识分布平衡性等"一致性维度"进行了归因分析。     

Controlling the familywise error rate with plug-in estimator for the proportion of true null hypotheses

Summary.  Estimation of the number or proportion of true null hypotheses in multiple-testing problems has become an interesting area of research. The first important work in this field was performed by Schweder and Spjøtvoll. Among others, they proposed to use plug-in estimates for the proportion of true null hypotheses in multiple-test procedures to improve the power. We investigate the problem of controlling the familywise error rate FWER when such estimators are used as plug-in estimators in single-step or step-down multiple-test procedures. First we investigate the case of independent p -values under the null hypotheses and show that a suitable choice of plug-in estimates leads to control of FWER in single-step procedures. We also investigate the power and study the asymptotic behaviour of the number of false rejections. Although step-down procedures are more difficult to handle we briefly consider a possible solution to this problem. Anyhow, plug-in step-down procedures are not recommended here. For dependent p -values we derive a condition for asymptotic control of FWER and provide some simulations with respect to FWER and power for various models and hypotheses.     

Dose-Response Assessment of Airborne Methyl Isothiocyanate (MITC) Following a Metam Sodium Spill

A tank car derailment in northern California in 1991 spilled metam sodium into the Sacramento River, and released its breakdown product, methyl isothiocyanate (MITC), into the air. This paper describes the risk evaluation process used. Over 240 individuals reported symptoms such as eye and throat irritation, dizziness, and shortness of breath. Reference exposure levels (RELs) for 1 hr were developed for MITC and compared to exposure concentrations. Ocular irritation in cats was the most sensitive endpoint reported. The no observed adverse effect level (NOAEL), divided by an uncertainty factor (UF) of 100, produced an REL of 0.5 ppb of MITC in air to prevent discomfort. An REL to prevent disability was estimated to be 40 ppb. An REL to prevent life-threatening injury was estimated to be 150 ppb. Measured MITC levels ranged from 0.2-37 ppb and estimated peak levels ranged from 140-1600 ppb. The usefulness of RELs for emergency planning is discussed.