共查询到17条相似文献,搜索用时 93 毫秒
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本文描述了顾客满意度抽样调查的估计值的精度,对影响抽样调查估计值精度的因素进行了分析;用案例说明了计算抽样样本量的方法,对调查组织确认精度时需要考虑的因素进行了简述; 提出了确认抽样样本量还应考虑的时间和资金等因素。 相似文献
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全文分析了GPS高程系统与我国现行高程系统的区别与联系;叙述了GPS高程拟合常用方法,对影响GPS高程拟合精度的因素进行了分析,提出了提高精度的方法。 相似文献
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作为全球低功耗FPGA供应商,莱迪思有着近40年的历史。2018年9月,董事会从AMD聘请Jim Anderson担任莱迪思CEO,从而组建了新的管理团队,团队中很多成员都是FPGA业界的精英。与此同时,新的管理团队也对公司产品、市场、运营战略、远景规划等进行了调整,这些调整得到了华尔街的正面肯定,公司股价开始大幅上涨,与2019年9月相比,股价有4倍多的增长,这也反应出投资人和市场对莱迪思的高度期望。 相似文献
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通过论述GPS控制网布设和全站仪三角高程测量方法,分析了高坎子电站测量过程中应遵守的测量限差要求及高程测量、GPS控制网的计算精度;然后对GPS控制网布设于山区水利工程的可靠性进行了验证,同时对四等水准测量精度能够采用全站仪测量的规定进行检验。 相似文献
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围岩变形预测是隧道安全评价及其指导后期施工的重要依据,为提高变形预测精度,结合工程实践,提出了PSO-SVM-BP预测模型的思路。首先,利用三次样条插值及二次平滑法对变形数据进行预处理,为后期变形预测奠定基础;其次,利用粒子群算法对支持向量机进行参数优化,建立PSO-SVM模型,并对围岩变形进行初步预测;最后,利用BP神经网络进行误差修正,达到综合预测的目的,并利用工程实例进行检验,以验证预测模型的有效性。结果表明:初步预测结果的相对误差均小于5%,而误差修正后的预测精度被提高到0.97%,预测精度较高,验证了预测模型的有效性,可为类似研究提供参考。 相似文献
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在FPGA实验教学和课程设计中,逻辑分析仪是最重要的调试工具。但由于高校经费紧张,难以配置齐全设备,而且逻辑分析仪I/O引脚引出困难,引脚数量有限,连线复杂,对内部信号的获取和分析也较困难。为此介绍一种SignalTapⅡ嵌入式逻辑分析仪,它成本低廉,升级方便,能对所有内部信号和外部引脚信号进行探测。通过对电路进行模块化的分析,合理设置触发条件,实现更有效、更准确的电路调试和排错。最后以PS2键盘接口电路的FPGA设计为例,阐明建立、配置和运行SignalTapⅡ的一些具体方法和步骤。 相似文献
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《Food Policy》2019
Previous studies on the adoption and impacts of improved crop varieties have relied on self-reported adoption status of the surveyed households. However, in the presence of weak variety maintenance and poorly functioning seed certification system, measurement errors in self-reported adoption status can be considerable. This paper investigates how such measurement errors can lead to biased welfare estimates. Using DNA-fingerprinting based varietal identification as a benchmark, we find that misclassification in self-reported adoption status is considerable, with significant false negative and positive response rates. We empirically show that such measurement errors lead to welfare estimates that are biased towards zero and substantially understate the poverty reduction effects of adoption. While the empirical evidence suggests attenuation bias, our theoretical exposition and simulations demonstrate that upward bias and sign reversal effects are also possible. The results point to the need for improved monitoring of the diffusion process of improved varieties through innovative adoption data collection approaches to generate robust evidence for prioritizing and justifying investments in agricultural research and extension. 相似文献
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Robert M. Yawson Wisdom K. Amoa-Awua Alistair J. Sutherland David R. Smith Seewu K. Noamesi 《R&D Management》2006,36(2):161-172
Research institutions in Ghana are facing various challenges. It is the contention that viable research and development institutions are needed for achieving sustainable change in areas of national importance. A key aspect of institutional viability is strong performance management. This implies clear and workable approaches to performance measurement. This paper looks at the initial experiences in a collaborative effort to develop a performance measurement framework for the Food Research Institute (FRI) and the application of the Balanced Score Card (BSC) at institutional level. The process of diagnosing and analysing institutional monitoring and evaluation capacity and systems is described using a mix of diagnostic tools. Stages in applying the BSC approach are documented and the added value of the scorecard perspectives in highlighting focal areas for performance measurement and management within FRI. These are placed in the context of ongoing changes in the external environment posing both threats and opportunities. Changes implied by the introduction of the concept are discussed in the context of current constraints and the way forward is mapped out in terms of enhancing FRIs' impact orientation through the application of improved performance measurement and management. 相似文献
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随着超声流量计在天然气计量领域的广泛应用,其自诊断技术也不断得到改进,为流量计现场计量的准确、可靠提供了保障。详细阐述了超声流量计的主要技术指标,以及波形图、增益值、信号质量、信噪比、流速特性等主要自诊断方法,还对声速核查法进行了介绍。有效利用超声流量计的自诊断与维护技术,不仅能确保流量计处于良好的运行状态、准确计量,也可核查计量系统中压力、温度和组分变化。 相似文献
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通过分析长庆油田技术监测中心计量技术机构目前的现状和存在的问题,根据计量服务保障能力达到的目标,提出了提升计量服务保障能力需做的主要工作是逐步完善量值传递与量值溯源体系、不断加强计量保障资源的配置、加强石油专用计量器具的管理与检测和构建计量管理信息服务平台。通过这些工作来提高计量检定站的计量服务保障能力,为大油田未来的发展提供坚强有力技术支持和服务保障。 相似文献
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