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11.
There is widespread application of indicators to the assessment of environmental condition of streams. These indicators are intended for use by managers in making various comparative and absolute assessments and often have a role in resource allocation and performance assessment. Therefore, the problem of formally defining confidence in the results is important but difficult because the sampling strategies used are commonly based on a compromise between the requirements of statistical rigour and the pragmatic issues of access and resources. It is rare to see this compromise explicitly considered and consequently there is seldom quantification of the uncertainty that could affect the confidence a manager has in an indicator. In this paper, we present a method for quantitatively assessing the tradeoffs between sampling density and uncertainty in meeting various monitoring objectives. Assessments using judgement‐based representative reaches are shown to be unreliable; instead a sampling approach is recommended based on the random selection of measuring sites. A detailed dataset was collected along two streams in Victoria, Australia, and the effect of sampling density was assessed by subsampling from this dataset with precision related to the number of sites assessed per reach length and the intensity of the sampling at each site. The sampling scheme to achieve a given precision is shown to depend on the monitoring objective. In particular, three objectives were considered: (1) making a baseline assessment of current condition; (2) change detection; and (3) detection of a critical threshold in condition. Change detection is shown to be more demanding than assessing baseline condition with additional sampling effort required to achieve the same precision. Sampling to detect a critical threshold depends on nominating acceptable values of Type I and II error and the size of the effect to be detected. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
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本文介绍了大坝施工混凝土质量的评价系统软件的设计思路和设计成果。它利用现代计算机技术和应用模糊数学理论评价混凝土重力坝和拱坝单块和整体的质量。在采用模糊综合评价工程质量中,对不同工艺环节,对坝体不同部位,鉴于其质量要求的差异应赋予不同的权重,在权重的取值上采用了专家调查排序,定量转化的方法是比较适宜的。在程序设计中,评价数学模型采用了BASIC程序,访膜块通过*TXT文件实现了与整个大坝混凝土质量微机管理系统的接口及数据传递。操作运行方便灵活。 相似文献
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安全性评价是一种现代化的管理手段。开展安全性评价可以提高水电站的安全生产管理水平和设备安全稳定运行水平。结合工作实践,介绍了周宁水电站安全性评价工作的实施过程、主要措施和取得的初步成效。 相似文献
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应用突变多准则评价法对南水北调中线水源工程项目的多方案比选作出评价决策。该方法为专家决策系统提供一种数学方法 ,以便用计算机实现多目标、多层次、多方案的评价决策。 相似文献
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Practitioners and regulators are concerned that when auditors perceive management's attitude or character as indicative of low fraud risk, they are not sufficiently sensitive to high levels of incentive or opportunity risks in their overall fraud‐risk assessments. In this study, we examine whether a fraud‐triangle decomposition of fraud‐risk assessments (that is, separately assessing attitude, opportunity, and incentive risks prior to assessing overall fraud risk) increases auditors' sensitivity to opportunity and incentive cues when perceptions of management's attitude suggest low fraud risk. In an experiment with 52 practicing audit managers, we find that auditors who decompose fraud‐risk assessments are more sensitive to opportunity and incentive cues when making their overall assessments than auditors who simply make an overall fraud‐risk assessment. However, this increased sensitivity to opportunity and incentive cues appears to happen only when those cues suggest low fraud risk. When opportunity and incentive cues suggest high fraud risk, auditors are equally sensitive to those cues whether they use a decomposition or a holistic approach. We discuss and examine potential explanations for this finding. 相似文献
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基于生态需水、河流纳污能力、水环境容量等理论,分析研究大通河调水前后可能引起的河道生态环境各要素变化的程度和范围。结果表明,跨流域调水将引起不同河段水资源的剧烈变化,特别是天堂寺、享堂河段会产生断流,进而对河道内生态、水环境及河谷周边陆地生态产生显著影响。综合各方面需水要求,下泄月平均流量至少不小于1.1 m3/s。 相似文献
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本文分析了电力商标的实质内涵,总结了电力商标的基本特征,在此基础上对商标的评估模型进行了创新构建,新建模型有两大特点:一是将商标收益分割为两部分计量;二是用强度系数进行了调整强化,为电力商标的评估提供一种新思路。 相似文献