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Anne F. Marrelli 《Performance Improvement》2007,46(9):43-47
This ninth article in the Performance Technologist's Toolbox series explores the data collection method of unobtrusive measures, which offer a diverse set of tools to reduce measurement reactivity. Their application in performance technology is outlined, the advantages and disadvantages of employing unobtrusive measures are summarized, and several basic guidelines are provided for their use. 相似文献
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Vasant Natarajan 《Resonance》2001,6(8):44-59
We trace the evolution of standards for weights and measures from olden days to their modern scientific definitions. Even in the era of modern science, standards till recently used to be defined by artifacts. It is only in the last few decades that we have gone over to definitions based on fundamental constants of nature. This has made the standards universally reproducible. The present standards for time, length, and electrical units are all based on physical constants. The mass standard, represented by the prototype kilogram, is the only remaining artifact, but there are promising proposals to replace that in the near future. 相似文献