期刊文献+
共找到7篇文章
< 1 >
每页显示 20 50 100
强余震持续时间的早期估计 被引量:3
1
作者 周翠英 王红卫 +1 位作者 王梅 张宇霞 《中国地震》 CSCD 北大核心 1997年第2期164-171,共8页
本研究旨在解决地震序列中强余震持续时间的早期估计问题。文中首先给出了强余震的震级定义,指出:主震型与强震群型序列的强余震持续时间存在差异。使用模式识别方法对主震型序列中强余震持续时间大于1天、小于1天及无强余震等3种... 本研究旨在解决地震序列中强余震持续时间的早期估计问题。文中首先给出了强余震的震级定义,指出:主震型与强震群型序列的强余震持续时间存在差异。使用模式识别方法对主震型序列中强余震持续时间大于1天、小于1天及无强余震等3种情况进行划分之后,给出了两类序列的强余震持续时间与序列第一大震震级的粗略相关关系。最后,给出了对于不同序列类型进行强余震持续时间估计的判断依据。 展开更多
关键词 余震 持续时间 模式识别 早期估计 地震群 强震
下载PDF
形式化规范在软件可靠性早期估计中的应用研究
2
作者 吕闽晖 吕敏蓉 《微型机与应用》 2011年第11期7-9,共3页
随着软件的广泛应用,特别是软件在尖端领域的应用,软件可靠性成为一个非常重要的问题。形式化规范在软件可靠性研究中能够起到的作用是多方面的。本文针对非形式化统计使用测试的不足,结合已有的早期可靠性估计方法,设计了优化算法,并... 随着软件的广泛应用,特别是软件在尖端领域的应用,软件可靠性成为一个非常重要的问题。形式化规范在软件可靠性研究中能够起到的作用是多方面的。本文针对非形式化统计使用测试的不足,结合已有的早期可靠性估计方法,设计了优化算法,并提出了即使在设计中采用了形式化规范仍然需要测试的结论。 展开更多
关键词 形式化规范 软件可靠性 早期估计 测试
下载PDF
基于人口流动大数据的传染病初期感染人数估计:以新冠肺炎为例
3
作者 韩鸿渐 谭索怡 +1 位作者 陈洒然 吕欣 《指挥与控制学报》 CSCD 北大核心 2024年第4期469-478,共10页
基于运营商提供的匿名、累计手机定位大数据,提取全国人口在春节期间的出行信息,并基于爆发地区人口流动情况构建模型推算武汉感染患者数量以及增长趋势。研究结果表明,截止武汉“封城”前,基于湖北省外50座城市感染情况构建DPNA-M模型... 基于运营商提供的匿名、累计手机定位大数据,提取全国人口在春节期间的出行信息,并基于爆发地区人口流动情况构建模型推算武汉感染患者数量以及增长趋势。研究结果表明,截止武汉“封城”前,基于湖北省外50座城市感染情况构建DPNA-M模型估计武汉感染人数为26464人,与依据境外检出概率的估计结果接近。与现有的估计方法相比,该模型不严格依赖于疫区统计数据,估计结果更准确,在模型稳健性与应用普适性方面更具优势。 展开更多
关键词 感染人数 早期估计 新冠肺炎 人口流动 检出概率
下载PDF
产时头位异常诊断与处理 被引量:1
4
作者 张秋侠 杨跃华 《医学研究通讯》 2001年第8期63-64,共2页
随着围生医学的进展,横位、臀位等异常胎位的发生率已明显下降,在头先露中,头位难产约占分娩总数的20%,多发生在分娩过程中,且易被忽略,因此,产时早期发现与正确处理头位异常是目前降低围生期母婴发病率的关键.头位难产临床表现为持续... 随着围生医学的进展,横位、臀位等异常胎位的发生率已明显下降,在头先露中,头位难产约占分娩总数的20%,多发生在分娩过程中,且易被忽略,因此,产时早期发现与正确处理头位异常是目前降低围生期母婴发病率的关键.头位难产临床表现为持续性枕后位、枕横位、胎头高直位、前不均倾位、颜面位、额位等异常头位. 展开更多
关键词 围生医学 异常胎位 头位异常 早期估计 诊断 临床表现 预防
下载PDF
Scientists Use Palaeobotanical Evidence to Estimate Early Miocene Elevation in Northern Tibet
5
《Bulletin of the Chinese Academy of Sciences》 2015年第4期239-240,共2页
The area and elevation of the Tibetan Plateau over time has directly affected Asia’s topography,the characteristics of the Asian monsoon,and modified global climate—but in ways that are poorly understood.Charting th... The area and elevation of the Tibetan Plateau over time has directly affected Asia’s topography,the characteristics of the Asian monsoon,and modified global climate—but in ways that are poorly understood.Charting the uplift history is crucial for understanding the mechanisms that link elevation and climate irrespective of time and place.While some palaeoelevation data are available for southern and central Tibet,clues to the uplift history of northern Tibet remain sparse and largely circumstantial.Lately, 展开更多
关键词 Tibet Miocene uplift Plateau elevation sparse understood poorly fossil monsoon
下载PDF
Early Stage CAD-Compliant Energy Performance Assessment Method
6
作者 Jarek Kumitski Targo Kalamees Teet Tark 《Journal of Energy and Power Engineering》 2013年第9期1662-1668,共7页
A simple calculator for early stage energy performance assessment in residential buildings was developed and partially validated in this study. The calculator is based on the correlation of heat loss and energy need f... A simple calculator for early stage energy performance assessment in residential buildings was developed and partially validated in this study. The calculator is based on the correlation of heat loss and energy need for heating and has fixed internal heat gains as intended for compliance assessment. With the calculator, the effect of any parameter implemented can be immediately seen on delivered and primary energy. Because of simple equations, it is suitable for implementation into CAD (computer aided design) design tools including basic BIM (building information modeling) data. Results showed that the accuracy of the correlation for the cases with practical relevance was not worse than 14% of the energy need of space heating. This applies for passive house insulation level; for less insulated building envelopes, the deviations were smaller. This 14% equals to only 3 kWh/(m2.a), i.e., the percentage difference in the total delivered and primary energy was much lower because of other components in the energy balance. The deviations determined were implemented in the calculator as safety margin. Results prove that simple energy performance assessment based on specific heat loss coefficient is well justified for early stage energy analyses as well as for compliance assessment implemented in Estonian regulation. 展开更多
关键词 Energy performance specific heat loss energy calculator early stage energy assessment compliance assessment.
下载PDF
Ovarian Cancer Screening Based on Mixture Change-Point Model
7
作者 ZOU Chenchen FANG Xiangzhong ZHAI Guanghe 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2015年第2期471-488,共18页
Ovarian cancer is one of the most deadly female genital malignant tumors in many regions while an effective early screening strategy can save numerous lives.CA125 and HE4 are tumor markers validated efficacious as wel... Ovarian cancer is one of the most deadly female genital malignant tumors in many regions while an effective early screening strategy can save numerous lives.CA125 and HE4 are tumor markers validated efficacious as well as most commonly used in recent screening research of ovarian cancer.In this paper,the authors construct a change-point and mixture model on the basis of longitudinal CA125 and HE4 levels and estimated parameters using maximum likelihood method with the preclinical duration assumed right-censored,which is more adaptive and yields comparable results in comparison to the Bayesian approach raised by Skates.Consistency of estimators is proved.The authors also run a 5-year simulation of sequential screening by calculating the risk of cancer and hypothesis testing the true incidence time respectively.Results show that diagnosis based on hypothesis test performs better in early detection. 展开更多
关键词 Change-point mixture model longitudinal data analysis maximum likelihood estimation ovarian caner screening.
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部