一种混合方式的无线传感器网络测试调试系统

无线传感器网络是典型的网络化嵌入式系统,由于其既涉及嵌入式系统的行为又涉及网络的行为,以及其应用相关性,使其测试调试变得困难复杂,无法构建一个通用的测试调试平台.为有效地测试调试无线传感器网络,在分析已有的研究工作基础上,采用半实物的仿真策略,提出了一种混合方式的无线传感器网络测试调试系统,解决了纯粹软件仿真平台掩盖太多实际器件实现的细节和实际环境测试中嵌入式系统行为和网络行为不可见、不可控性的缺陷,达到了一种折中的效果.最后给出了该系统在FPGA(field programmable gate array)上的实现实例;通过实验验证了该系统能够有效地对无线传感器网络应用进行测试调试.     

转子动平衡测试实验平台的一种实现方法

汽轮机发电机组是一种高速旋转机械 ,其振动的大小是机组安装、检修和运行等技术管理水平高低的一个重要标志。本文介绍了一种测试汽轮机动平衡的实验平台设计 ,该实验平台是基于VC ++6 .0的编程环境 ,将VC ++6 .0用于实验平台的开发 ,以VC ++6 .0对话框作为参数输入、实验结果输出和帮助界面。同时利用OpenGL开发了一个Active控件以实现汽轮机转子的转动。     

连铸机二冷设计中喷嘴的选择和测试

从连铸机喷嘴的分类入手,对各种喷嘴的特性进行了简要说明并结合研究实践,对某板坯连铸机选用的D25型系列喷嘴的测试做了探讨,包括测试内容、测试结果以及高差对水喷嘴喷水量的影响情况等。     

基于代价敏感学习的钢铁企业转炉煤气柜柜位预测

钢铁企业转炉煤气柜柜位的准确预测可为煤气系统调度提供重要依据,然而鉴于转炉煤气(Linz Donawitz gas, LDG)回收的冲击性,调度人员对柜位的超上限问题尤为关注。为此,依托大量系统运行数据,提出了一种基于代价敏感学习支持向量机(support vector machine, SVM)的转炉煤气柜柜位预测方法,可提高对柜位超上限情况的预报精度。该方法以LDG回收流量、LDG消耗流量等作为输入,以未来柜位值作为输出,利用KKT方程,将原约束条件转化为等式约束,对煤气柜位超限误报和未超限误报设定了不同的代价;最终通过最小化模型漏报误差,将原预测问题转化为一系列线性方程并求解。针对国内某钢铁厂数据的仿真实验结果表明,所提方法将LDG柜位超限状况的漏报率降低至0.16%,可为调度人员制定合理的调度策略提供更快速有效的指导。     

一种用于铝合金材料的多频涡流测试技术

研究了基于多频涡流测量的铝合金材料检测方法。试验中采用放置式参量传感器(探头),并采用Walsh函数进行信号处理,以降低检测误差。以特制的铝镁合金试块为检测对象,得到缺陷处的Hodograph曲线。研究模拟了材料中检测面下不同深度处的表面缺陷对Hodograph曲线形态的影响。定量描述了不同缺陷处的Hodograph曲线相对于无缺陷区域的位移变化。根据缺陷和探头之间的距离的位移变化量,可确定缺陷位置并评价其埋藏深度。试验表明,此方法对于监测和发现和铝合金材料的缺陷具有较高的准确性和适用性。     

丹麦开发出一种可用于产品防伪识别的新技术

正丹麦研究人员近日开发出一种利用稀土元素的光学特性给产品打上"指纹"的新技术,从而可以实现对商品的防伪识别。丹麦哥本哈根大学的研究人员在新一期美国学术刊物《科学进展》上发表的论文说,研究人员将分别添加了稀土元素铕、铽和镝的三堆沙粒混合起来,然后随机取出部分沙粒,嵌入需要防伪的产品所用材料中,例如可嵌入皮革、玻璃或金属中。这三种稀土元素分别会在特定波长的光照射下发光,所以制造商可对产品中嵌入沙粒部位在不同波长下各拍     

用于开路非晶薄带动态磁性测试的一种新方法

本文叙述了基于叠加原理在5kHz到200kHz及中等磁感下测试开路非晶薄带动态磁性的一种新方法。该方法除简化了对试样的要求外,具有操作方便的优点。文章提供了实验方法和实验细节,讨论了测试误差及测试结果。     

一种改进的最大相关最小冗余选择性贝叶斯分类器

利用K均值聚类和增量学习算法扩大训练样本规模,提出一种改进的mRMR SBC.一方面,利用K均值聚类预测测试样本的类标签,将已标记的测试样本添加到训练集中,并在属性选择过程中引入一个调节因子以降低K均值聚类误标记带来的风险.另一方面,从测试样本集中选择有助于提高当前分类器精度的实例,把它加入到训练集中,来增量地修正贝叶斯分类器的参数.实验结果表明,与mRMR SBC相比,所提方法具有较好的分类效果,适于解决高维且含有较少类标签的数据集分类问题.     

一种同时炼铅锌的新技术

开发了一种同时炼铅锌的新技术,利用富氧侧吹(或底吹)炉和密闭富氧侧吹炉代替了传统技术中使用的烧结机和密闭鼓风炉。该技术改善了传统技术中存在的高焦率、低空污染、烟气含硫低、大量返尘等问题,具有可行性和潜在市场。     

中低合金钢化学成分能力验证样品制备及均匀性检验流程探讨

选取和制备在测试水平、基质等方面与参加者日常检测样品相同或相似,且均匀性优良的能力验证样品,一直是成功开展实验室能力验证活动的关键。通过具有典型意义的中低合金钢能力验证项目运作和实施,探讨并给出此类能力验证项目在样品选材、加工、制备,以及样品均匀性检验方面的一般原则和方法,并对中低合金钢能力验证样品制备及均匀性检验相关问题进行探讨。希望此研究能够对从事相关能力验证工作的人员具有一定的帮助和指导作用。     

Revival of test bias research in preemployment testing.

We developed a new analytic proof and conducted Monte Carlo simulations to assess the effects of methodological and statistical artifacts on the relative accuracy of intercept- and slope-based test bias assessment. The main simulation design included 3,185,000 unique combinations of a wide range of values for true intercept- and slope-based test bias, total sample size, proportion of minority group sample size to total sample size, predictor (i.e., preemployment test scores) and criterion (i.e., job performance) reliability, predictor range restriction, correlation between predictor scores and the dummy-coded grouping variable (e.g., ethnicity), and mean difference between predictor scores across groups. Results based on 15 billion 925 million individual samples of scores and more than 8 trillion 662 million individual scores raise questions about the established conclusion that test bias in preemployment testing is nonexistent and, if it exists, it only occurs regarding intercept-based differences that favor minority group members. Because of the prominence of test fairness in the popular media, legislation, and litigation, our results point to the need to revive test bias research in preemployment testing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

High stakes testing in higher education and employment: Appraising the evidence for validity and fairness.

The authors review criticisms commonly leveled against cognitively loaded tests used for employment and higher education admissions decisions, with a focus on large-scale databases and meta-analytic evidence. They conclude that (a) tests of developed abilities are generally valid for their intended uses in predicting a wide variety of aspects of short-term and long-term academic and job performance, (b) validity is not an artifact of socioeconomic status, (c) coaching is not a major determinant of test performance, (d) tests do not generally exhibit bias by underpredicting the performance of minority group members, and (e) test-taking motivational mechanisms are not major determinants of test performance in these high-stakes settings. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

多元体系铂饰品校正样品的研制及在X射线荧光无损检测中应用

研制了成分为Pt,Pd,Au,Ag,Cu,Zn,Ni,Co的多元体系的铂饰校正样品,并用于多元体系铂饰品的X射线荧光光谱无损检测,结果令人满意。测量结果误差<1.0%,符合GB/T18043-2000国家标准规定的允许差,方法RSD小于3.0%。     

Responses to issues raised about validity, bias, and fairness in high-stakes testing.

We are pleased that our article (see record 2008-05553-001) prompted this series of four commentaries and that we have this opportunity to respond. We address each in turn. Duckworth (see record 2009-06923-012) and Kaufman and Agars (see record 2009-06923-013) discussed, respectively, two broad issues concerning the validity of selection systems, namely, the expansion of the predictor domain to include noncognitive predictors of performance and the expansion of the criterion domain to include additional criteria (e.g., creativity). We agree with these arguments, noting that they expand on points made in our original article. Wicherts and Millsap (see record 2009-06923-014) rightly noted the distinction between measurement bias and predictive bias and the fact that a finding of no predictive bias does not rule out the possibility that measurement bias still exists. They took issue with a statement we cited from Cullen, Hardison, and Sackett (2004) that if motivational mechanisms, such as stereotype threat, result in minority group members obtaining lower observed scores than true scores (i.e., a form of measurement bias), then the performance of minority group members should be under predicted. Our characterization of Cullen et al.’s (2004) statement was too cryptic; what was intended was a statement to the effect that if the regression lines for majority and minority groups are identical at the level of true predictor scores, then a biasing factor resulting in lower observed scores than true scores for minority group members would shift the minority group regression line to result in under prediction for that group. We do agree with Helms’s (see record 2009-06923-015) call for studying the reasons why racial- group differences are found and encourage this line of research; however, we view the study of racial-group differences and the study of determinants of those differences as complementary. We thank the authors for contributing these commentaries and for stimulating this discussion. Duckworth (2009) and Kaufman and Agars (2009) discussed important issues regarding expanding the predictor and criterion domains. Wicherts and Millsap (2009) correctly noted distinctions between predictive and measurement bias and used stereotype threat as a mechanism to discuss these issues. Helms (2009) raised several issues regarding the validity and fairness of standardized tests. In all cases, we welcomed the opportunity to discuss these topics and provide more detail on issues relating to high-stakes standardized testing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

冶金标准样品在分析测试领域中的应用

介绍了标准样品研制工作程序、制取、加工等,并阐述了标准样品在分析测试领域中的应用。     

能力验证活动在济钢的实践探索

根据实验室实际应用的经验及相关标准,分析了组织和设计能力验证活动时需考虑的因素,总结了参加能力验证活动时需遵循的基本原则,对类似实验室有效开展能力验证活动具有一定的指导意义。     

Testing for adverse impact when sample size is small.

Adverse impact evaluations often call for evidence that the disparity between groups in selection rates is statistically significant, and practitioners must choose which test statistic to apply in this situation. To identify the most effective testing procedure, the authors compared several alternate test statistics in terms of Type I error rates and power, focusing on situations with small samples. Significance testing was found to be of limited value because of low power for all tests. Among the alternate test statistics, the widely-used Z-test on the difference between two proportions performed reasonably well, except when sample size was extremely small. A test suggested by G. J. G. Upton (1982) provided slightly better control of Type I error under some conditions but generally produced results similar to the Z-test. Use of the Fisher Exact Test and Yates's continuity-corrected chi-square test are not recommended because of overly conservative Type I error rates and substantially lower power than the Z-test. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparability of Wonderlic test forms in industrial testing.

Are the 5 forms of the Wonderlic Personnel Test really equivalent? "Sixteen groups consisting of 590 male applicants for apprenticeship programs in a large manufacturing company were tested using all 5 forms of the Wonderlic Personnel Test (Forms A, B, D, E and F… . it is recommended that Form B of the Personnel Test not be regarded as directly equivalent to any of the other four forms of the test and that Form D not be regarded as directly equivalent to Form F in industrial testing situations similar to the one in the present study." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

金矿石加工及测试质量过程控制

金矿石样品加工、测试质量过程控制是获得分析结果准确度的重要前提。在大量生产实践基础上,总结了样品加工、测试中影响分析结果准确度的重要要素。根据不同金矿石类型制定了不同加工制备流程,分析了影响样品加工制备质量的要素;论述了取样量选择、试样焙烧、测试方法选择、不同类型标准曲线等因素对测定结果的影响。实践证明,加强金矿石加工、测试质量过程控制,就能够取得满意的分析结果。