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两组率同为100%或0%时率差置信区间估计的SAS实现 被引量:1
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作者 黄耀华 唐欣然 +1 位作者 段重阳 陈平雁 《中国卫生统计》 CSCD 北大核心 2017年第1期11-14,共4页
目的通过SAS编程实现两组事件发生率均为0%或100%时率差置信区间的估计。方法针对事件发生率均为100%或0%时率差置信区间的估计问题,采用SAS9.4编程,使置信区间估计的Miettinen Nurminen法、Newcombe-Wilson法及校正New combe-Wilson法... 目的通过SAS编程实现两组事件发生率均为0%或100%时率差置信区间的估计。方法针对事件发生率均为100%或0%时率差置信区间的估计问题,采用SAS9.4编程,使置信区间估计的Miettinen Nurminen法、Newcombe-Wilson法及校正New combe-Wilson法等三种方法得以实现,并通过实例进行说明。结果所编程序实现了三种方法的置信区间估计,便于专业和非专业人员使用。实例中两组样本量分别为59,56,结果两组事件发生率均为100%,三种方法的95%置信区间:Miettinen Nurminen法为[-6.16%,6.47%];Newcombe法为[-6.11%,6.42%];校正Newcombe法为[-7.62%,8.00%]。结论本文所提供的SAS宏程序可以简便地实现两组事件发生率均为0%或100%时三种常用的率差置信区间的估计方法。 展开更多
关键词 置信区间 SAS宏程序 Newcombe法 Miettinen Nurminen法
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基于区块链的云数据完整性审计方案
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作者 高改梅 高茂林 +2 位作者 党伟超 刘春霞 白尚旺 《计算机工程与设计》 北大核心 2024年第8期2281-2289,共9页
针对云存储数据完整性审计效率低的问题,提出一种基于区块链的云数据完整性审计方案。以树结构保存证据信息,状态通道内完成审计“挑战-验证”,实现高效审计;通过局部置信率随机抽取数据块生成挑战,聚合数据物理性和逻辑性生成挑战对应... 针对云存储数据完整性审计效率低的问题,提出一种基于区块链的云数据完整性审计方案。以树结构保存证据信息,状态通道内完成审计“挑战-验证”,实现高效审计;通过局部置信率随机抽取数据块生成挑战,聚合数据物理性和逻辑性生成挑战对应验证证据,实现数据的逻辑性完整验证;智能合约将审计结果打包成交易并保存区块中,实现审计结果的可追踪性。实验结果表明,BCDIAS方案提供数据隐私保护,能抵御单体攻击,整体审计效率提升12.14%,对实际应用场景有一定参考价值。 展开更多
关键词 区块链 云数据存储 完整性审计 状态通道 局部置信率 挑战-验证 去中心化
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面向SAR目标识别深度网络可理解的类激活映射方法
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作者 崔宗勇 杨致远 +2 位作者 蒋阳 曹宗杰 杨建宇 《雷达学报(中英文)》 EI CSCD 北大核心 2024年第2期428-442,共15页
随着深度学习方法在合成孔径雷达(SAR)图像解译领域的广泛应用,SAR目标识别深度网络可理解性问题逐渐受到学者的关注。类激活映射(CAM)作为常用的可理解性算法,能够通过热力图的方式,直观展示对识别任务起作用的显著性区域。然而作为一... 随着深度学习方法在合成孔径雷达(SAR)图像解译领域的广泛应用,SAR目标识别深度网络可理解性问题逐渐受到学者的关注。类激活映射(CAM)作为常用的可理解性算法,能够通过热力图的方式,直观展示对识别任务起作用的显著性区域。然而作为一种事后解释的方法,其只能静态展示当次识别过程中的显著性区域,无法动态展示当输入发生变化时显著性区域的变化规律。该文将扰动的思想引入类激活映射,提出了一种基于SAR背景杂波特性类激活映射方法(SCC-CAM),通过对输入图像引入同分布的全局扰动,逐步向SAR识别深度网络施加干扰,使得网络判决发生翻转,并在此刻计算网络神经元输出激活值的变化程度。该方法既能解决添加扰动可能带来的扰动传染问题,又能够动态观察和度量目标识别网络在识别过程中显著性区域的变化规律,从而增强深度网络的可理解性。在MSTAR数据集和OpenSARShip-1.0数据集上的试验表明,该文提出的算法具有更加精确的定位显著性区域的能力,相比于传统方法,在平均置信度下降率、置信度上升比例、信息量等评估指标上,所提算法具有更强的可理解性,能够作为通用的增强网络可理解性的方法。 展开更多
关键词 SAR目标识别 网络可理解性 SAR杂波特性 类激活映射 面积约束置信度下降
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一种基于差分隐私保护的skyline查询方法
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作者 张丽平 杨玉 +2 位作者 金飞虎 李松 郝忠孝 《西南交通大学学报》 EI CSCD 北大核心 2022年第5期982-989,共8页
为了解决差分隐私保护机制中重复攻击会泄露用户隐私的问题,提出了一种基于动态页敏感度调节的skyline查询方法.首先,提出了依据最优主导页的计算页敏感度方法,提高页敏感度计算的效率;其次,为了合理设置隐私预算值,提出了基于置信率的... 为了解决差分隐私保护机制中重复攻击会泄露用户隐私的问题,提出了一种基于动态页敏感度调节的skyline查询方法.首先,提出了依据最优主导页的计算页敏感度方法,提高页敏感度计算的效率;其次,为了合理设置隐私预算值,提出了基于置信率的隐私预算值调节方法;最后,基于隐私预算值动态更新查询次数的上界,实现了基于差分隐私保护的skyline查询方法.实验结果表明:所提出方法在隐私预算值设定小于0.8时,隐私数据的泄露数由787个降低到423个. 展开更多
关键词 SKYLINE查询 页敏感度 置信率 动态隐私预算 最大范围查询
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2×2列联表在图书馆管理中的应用 被引量:1
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作者 魏曾甫 《图书馆学研究》 1982年第4期37-42,共6页
前言由于我国社会主义经济建设和科学技术的日益迅速发展,广大自然科学和社会科学工作者及工农兵群众对于图书资料的要求更为迫切,为了更好地为四个现代化服务,图书馆的管理科学必须跟上去。图书馆统计学也是为这一目的服务的,它主要研... 前言由于我国社会主义经济建设和科学技术的日益迅速发展,广大自然科学和社会科学工作者及工农兵群众对于图书资料的要求更为迫切,为了更好地为四个现代化服务,图书馆的管理科学必须跟上去。图书馆统计学也是为这一目的服务的,它主要研究图书馆现象过程中的数量规律性。但目前我国图书馆统计学还处于使用比较初等的统计方法的阶段,本文试图介绍一些比较现代化的数理统计方法来充实图书馆统计学的内容。 展开更多
关键词 列联表 图书馆统计 图书馆管理 研究对象 相互独立 拒借 置信率 社会主义经济建设 置信区间 指标
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建立炼油综合自用测算模型
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作者 况冶 《齐鲁石油化工》 1999年第2期104-106,共3页
提出了炼油厂重要的技术经济指标——炼油综合自用率的测算模型,对模型采用的测算方法和模型结构、功能进行了阐述。通过提出统计指标比照置信率的概念。
关键词 统计值 测算值 测算模型 置信率 炼油厂 能耗
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Mode Selection and Resource Allocation for Deviceto-Device Communications in 5G Cellular Networks 被引量:6
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作者 Fan Jiang Benchao Wang +2 位作者 Changyin Sun Yao Liu Rong Wang 《China Communications》 SCIE CSCD 2016年第6期32-47,共16页
To meet the increasing demand of wireless broadband applications in future 5G cellular networks, Device-to-Device(D2D) communications serve as a candidate paradigm to improve spectrum efficiency. Considering the chall... To meet the increasing demand of wireless broadband applications in future 5G cellular networks, Device-to-Device(D2D) communications serve as a candidate paradigm to improve spectrum efficiency. Considering the challenges after D2 D transmission is introduced for future cellular networks, this paper deals with mode selection and resource allocation issues related with D2 D communications. First, we propose a mode selection scheme which aims at guaranteeing the transmission of cellular users and also considering the potential interference. We analyze the condition under which D2 D underlay mode should be used. Second, we answer the question of "how to effectively reuse cellular resource once underlaying mode is adopted". We further present a resource allocation scheme that focuses on minimizing overall interference as well as a power control method to improve the performance of D2 D systems. Simulation results demonstrate that system parameters greatly affect the switching condition of mode selection and probability of choosing underlay mode. Furthermore, for D2 D underlaying scenario, the proposed resource allocation algorithm guarantees the transmission of cellular users with consideration of transmission requirements of D2 D users. Hence, the proposed scheme can achieve better user experience. 展开更多
关键词 device-to-device communication mode selection resource allocation power control
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基于多种约束条件的维修备件库存优化方法研究 被引量:3
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作者 毛宇 黄之杰 +4 位作者 李威 周扬 王威 刘信斌 刘慎洋 《数学的实践与认识》 北大核心 2018年第10期163-166,共4页
考虑了维修备件需求的随机性,以装备可用度、完好率置信度以及维修备件的保障程度为约束条件,运用概率论与数理统计方法,将维修备件保障费用达到最小值确定为目标函数,在此基础上,制定维修备件库存的最优方案,并通过示例验证了该... 考虑了维修备件需求的随机性,以装备可用度、完好率置信度以及维修备件的保障程度为约束条件,运用概率论与数理统计方法,将维修备件保障费用达到最小值确定为目标函数,在此基础上,制定维修备件库存的最优方案,并通过示例验证了该方法的有效性和科学性.方法可以为其它相关领域解决物资库存与费用问题提供理论依据. 展开更多
关键词 可用度 完好置信 保障程度 保障费用 库存优化
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Fluorocarbon paint on Daya Bay antineutrino detectors 被引量:1
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作者 WANG RuiGuang HENG YueKun +4 位作者 WANG Lan DING YaYun CAO Jun WANG YiFang YANG ChangGen 《Science China(Technological Sciences)》 SCIE EI CAS 2012年第6期1572-1575,共4页
The aim of the Daya Bay reactor antineutrino experiment is to determine the neutrino mixing angle 813 with a sensitivity of 0.01 or better at 90% confidence level. In order to improve the position resolution of both t... The aim of the Daya Bay reactor antineutrino experiment is to determine the neutrino mixing angle 813 with a sensitivity of 0.01 or better at 90% confidence level. In order to improve the position resolution of both the positron interaction and the neu- tron capture, the inside of the antineutrino detectors should be as unreflecting as possible. A black matt fluorocarbon paint is coated on the inner surface of the detectors made of 304L stainless steel to meet the physical requirement. This paint is com- patible with mineral oil, has low radioactivity, is easy to spray and fast curing at normal temperatures. The coating has excel- lent performance such as good adhesive force, uniformity, compact, scratch and wear resistance, and so on. It is the first appli- cation of such paint to large physical devices. 展开更多
关键词 NEUTRINO DETECTOR fluorocarbon paint REFLECTIVITY compatibility
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Pressure Fluctuation Generated by the Interaction of Blade and Tongue 被引量:4
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作者 ZHENG Lulu DOU Hua-Shu +2 位作者 CHEN Xiaoping ZHU Zuchao CUI Baoling 《Journal of Thermal Science》 SCIE EI CAS CSCD 2018年第1期8-16,共9页
Pressure fluctuation around the tongue has large effect on the stable operation of a centrifugal pump. In this paper, the Reynolds averaged Navier-Stokes equations (RANS) and the RNG k-epsilon turbulence model is em... Pressure fluctuation around the tongue has large effect on the stable operation of a centrifugal pump. In this paper, the Reynolds averaged Navier-Stokes equations (RANS) and the RNG k-epsilon turbulence model is employed to simulate the flow in a pump. The flow field in the centrifugal pump is computed for a range of flow rate. The simulation results have been compared with the experimental data and good agreement has been achieved. In order to study the interaction of the tongue with the impeller, fifteen monitor probes are evenly distributed circumferentially at three radii around the tongue. Pressure distribution is investigated at various blade positions while the blade approaches to and leaves the tongue region. Results show that pressure signal fluctuates largely around the tongue, and it is more intense near the tongue surface. At design condition, standard deviation of pressure fluctua- tion is the minimum. At large flow rate, the increased low pressure region at the blade trailing edge results in the increases of pressure fluctuation amplitude and pressure spectra at the monitor probes. Minimum pressure is obtained when the blade is facing to the tongue. It is found that the amplitude of pressure fluctuation strongly depends on the blade positions at large flow rate, and pressure fluctuation is caused by the relative movement between blades and tongue. At small flow rate, the rule of pressure fluctuation is mainly depending on the structure of vortex flow at blade passage exit besides the influence fTom the relative position between the blade and the tongue. 展开更多
关键词 centrifugal pump pressure fluctuation INSTABILITY numerical simulation
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An interval effective independence method for optimal sensor placement based on non-probabilistic approach 被引量:6
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作者 YANG Chen LU ZiXing 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2017年第2期186-198,共13页
This paper presents an interval effective independence method for optimal sensor placement, which contains uncertain structural information. To overcome the lack of insufficient statistic description of uncertain para... This paper presents an interval effective independence method for optimal sensor placement, which contains uncertain structural information. To overcome the lack of insufficient statistic description of uncertain parameters, this paper treats uncertainties as non-probability intervals. Based on the iterative process of classical effective independence method, the proposed study considers the eliminating steps with uncertain cases. Therefore, this method with Fisher information matrix is extended to interval numbers, which could conform to actual engineering. As long as we know the bounds of uncertainties, the interval Fisher information matrix could be obtained conveniently by interval analysis technology. Moreover, due to the definition and calculation of the interval relationship, the possibilities of eliminating candidate sensors in each iterative process and the final layout of sensor placement are both presented in this paper. Finally, two numerical examples, including a five-storey shear structure and a truss structure are proposed respectively in this paper. Compared with Monte Carlo simulation, both of them can indicate the veracity of the interval effective independence method. 展开更多
关键词 optimal sensor placement interval effective independence method non-probabilistic approach interval Fisher information matrix interval possibility
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