在进行多中心临床试验研究或大规模流行病学调查之前,需要通过小规模的重复测量来评价测试者(或仪器、量表、方法等)的信度与效度,以决定在大规模调查时控制测量误差的策略。这就涉及到一致性检验(test of concordance,test of agreeme...在进行多中心临床试验研究或大规模流行病学调查之前,需要通过小规模的重复测量来评价测试者(或仪器、量表、方法等)的信度与效度,以决定在大规模调查时控制测量误差的策略。这就涉及到一致性检验(test of concordance,test of agreement)问题。初学者往往对其中的一些用法、统计量及计算等存在混淆,本文就如何选择一致性检验方法及利用有关统计软件等予以简要介绍。1 测量误差与一致性检验 测量误差是调查研究中偏倚(bias)的主要来源,它有时可导致与事实相悖的结论。因此选择或发展准确的测量工具是研究中至关重要的一步。评价测量工具的准确性或其“展开更多
针对基于加速模型参数不变、基于统计方法及基于试验观察3种常见的失效机理一致性检验方法进行研究,发现3种方法均需要加速试验数据来对失效机理一致性进行检验,不能事先为加速试验提供理论指导;提出了一种基于灰色理论的失效机理一致...针对基于加速模型参数不变、基于统计方法及基于试验观察3种常见的失效机理一致性检验方法进行研究,发现3种方法均需要加速试验数据来对失效机理一致性进行检验,不能事先为加速试验提供理论指导;提出了一种基于灰色理论的失效机理一致性检验方法,该方法可用预试验数据进行失效机理一致性检验,为加速试验制定最高应力台阶提供理论指导;结合某型光电编码器预试验数据对该方法进行实例验证,得出175℃附近为失效机理变化点,并与基于统计的方法进行对比;最后,对产品进行失效机理分析,利用扫描电镜分析(SEM,Scanning Electron Microscope)结果验证该方法的正确性.展开更多
This paper addresses the issue of checking consistency in information models. A method based on constraint programming is proposed for identifying inconsistency or proving consistency in information models. The system...This paper addresses the issue of checking consistency in information models. A method based on constraint programming is proposed for identifying inconsistency or proving consistency in information models. The system described here checks information models written in the ISO standard information modelling language EXPRESS. EXPRESS is part of the ISO STEP standard used in the manufacturing and process industries. This paper describes the checking procedure, including EXPRESS model formalization, constraint satisfaction problem (CSP) derivation from the formalized model and satisfaction checking of the derived CSPs. This paper shows a new domain in which constraint programming can be exploited as model verification and validation.展开更多
Four rapid spectral comparison methods are introduced in mobile labs.They are conformity test method,general correlation coefficient method,reverse correlation coefficient method and correlation coefficient method usi...Four rapid spectral comparison methods are introduced in mobile labs.They are conformity test method,general correlation coefficient method,reverse correlation coefficient method and correlation coefficient method using characteristic spectral ranges.The first method is used for tracking the movements of drugs in the distribution channels;the second is used for quickly identify new counterfeit drugs;the last two are used to screen drugs illegally added in Traditional Chinese Medicine （TCM）.The applicability of the four methods is evaluated with counterfeit and authentic drugs.Our results show that these methods can be quickly constructed and used to identify counterfeit drugs accurately.展开更多
文摘在进行多中心临床试验研究或大规模流行病学调查之前,需要通过小规模的重复测量来评价测试者(或仪器、量表、方法等)的信度与效度,以决定在大规模调查时控制测量误差的策略。这就涉及到一致性检验(test of concordance,test of agreement)问题。初学者往往对其中的一些用法、统计量及计算等存在混淆,本文就如何选择一致性检验方法及利用有关统计软件等予以简要介绍。1 测量误差与一致性检验 测量误差是调查研究中偏倚(bias)的主要来源,它有时可导致与事实相悖的结论。因此选择或发展准确的测量工具是研究中至关重要的一步。评价测量工具的准确性或其“
文摘针对基于加速模型参数不变、基于统计方法及基于试验观察3种常见的失效机理一致性检验方法进行研究,发现3种方法均需要加速试验数据来对失效机理一致性进行检验,不能事先为加速试验提供理论指导;提出了一种基于灰色理论的失效机理一致性检验方法,该方法可用预试验数据进行失效机理一致性检验,为加速试验制定最高应力台阶提供理论指导;结合某型光电编码器预试验数据对该方法进行实例验证,得出175℃附近为失效机理变化点,并与基于统计的方法进行对比;最后,对产品进行失效机理分析,利用扫描电镜分析(SEM,Scanning Electron Microscope)结果验证该方法的正确性.
文摘This paper addresses the issue of checking consistency in information models. A method based on constraint programming is proposed for identifying inconsistency or proving consistency in information models. The system described here checks information models written in the ISO standard information modelling language EXPRESS. EXPRESS is part of the ISO STEP standard used in the manufacturing and process industries. This paper describes the checking procedure, including EXPRESS model formalization, constraint satisfaction problem (CSP) derivation from the formalized model and satisfaction checking of the derived CSPs. This paper shows a new domain in which constraint programming can be exploited as model verification and validation.
基金National Key Technologies R&D Program Foundation of China(Grant No.2008BAI55B06).
文摘Four rapid spectral comparison methods are introduced in mobile labs.They are conformity test method,general correlation coefficient method,reverse correlation coefficient method and correlation coefficient method using characteristic spectral ranges.The first method is used for tracking the movements of drugs in the distribution channels;the second is used for quickly identify new counterfeit drugs;the last two are used to screen drugs illegally added in Traditional Chinese Medicine （TCM）.The applicability of the four methods is evaluated with counterfeit and authentic drugs.Our results show that these methods can be quickly constructed and used to identify counterfeit drugs accurately.
