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1.
A method for estimating long-term distributions of exposure based on repeated short-term measurements within the same population is developed. If the short-term measurements span seasonal variation, and if the distributions are log-normal or nearly so, then long-term distributions can be estimated from as few as two visits to the same population. The method is illustrated using examples drawn from EPA's TEAM Study of exposures to volatile organic compounds. 相似文献
2.
随着经济的不断发展,开展同业税负研究测算的意义也愈显重要.传统行业税负计算方法没有考虑非正常样本对计算结果的影响,所得到的税负平均值往往低于行业税负的正常值.本文首次将C4.5数据挖掘算法引入到行业税负测算过程中,有效避免了传统测算方法中的不足,并结合税收领域知识对该算法进行了改进应用;通过对算法测算结果进行验证表明,利用该算法选出的企业样本代表了真实的行业税负水平,具有很高的可信度. 相似文献