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基于初始基准态的FAST反射面索网结构性能优化分析研究 被引量:5
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作者 罗斌 郭正兴 +1 位作者 王凯 肖全东 《土木工程学报》 EI CSCD 北大核心 2015年第12期12-22,共11页
500m口径射电望远镜FAST反射面索网结构,由短程线型面索网和下拉索构成,采用高强度预应力钢绞线束索,主动变位工作是其最大特点。索网优化设计采用容许应力法,基于索网为形控结构,提出标准球面基准态优化分析方法:根据主动变位工作基本... 500m口径射电望远镜FAST反射面索网结构,由短程线型面索网和下拉索构成,采用高强度预应力钢绞线束索,主动变位工作是其最大特点。索网优化设计采用容许应力法,基于索网为形控结构,提出标准球面基准态优化分析方法:根据主动变位工作基本要求和主动变位引起的面索应变变化幅值一定,首先确定下拉索初张力值和面索初应力上、下限值,通过找力分析确定面索初张力后,以初应力接近上限为原则确定面索截面规格。分析若干关键因素对索网结构性能的影响,结果表明:为避免工作态出现过低下拉索力,在面索弹性模量和容许应力一定的条件下,只能通过维持面索初应力水平,增大面索截面积来提高下拉索和面索初张力;周圈钢桁架宜采用滑动支座和较低刚度,并可采取周圈钢桁架沿径向预偏安装、边缘下拉索张拉固定后不参与主动变位的措施;钢索安全系数从2.5调低至2.0,可提高容许应力和面索初应力上限、减少材料和改善内力状况。另外,通过对比碳纤维索和钢索的力学特性,高强、低弹模、轻质量、抗疲劳的碳纤维索适合FAST索网结构。 展开更多
关键词 FAST 索网 初始基准态 结构性能 优化分析
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基于基准态的断路器可靠性分析方法 被引量:2
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作者 黄荣辉 李穆 吕启深 《电气工程学报》 2017年第1期33-39,共7页
利用基准态的概念,针对高压断路器的可靠性分析,提出了一套完整的理论方法。首先,根据基准态建立过程中选取的关键状态量,开展关键状态量分析技术,深入分析关键状态量性能的好坏。并引入电网强度、设备强度和设备老化程度3个维度的性能... 利用基准态的概念,针对高压断路器的可靠性分析,提出了一套完整的理论方法。首先,根据基准态建立过程中选取的关键状态量,开展关键状态量分析技术,深入分析关键状态量性能的好坏。并引入电网强度、设备强度和设备老化程度3个维度的性能,评判设备分性能状况,得到设备基准态值。接着,基准态预测过程作为基准态分析的延伸,以经典统计学理论获取预测模型,为设备基准态发展趋势提供参考。最后,可靠性分析则是基准态分析的最终目的和落脚点,利用经典可靠性理论,构建可靠度模型,绘制设备可靠性曲线。从曲线中可方便获取设备当前及未来的可靠度,为用户的运维及检修工作提供决策支持。 展开更多
关键词 基准态 预测 可靠性
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机载实时模型稳态基准值的修正方法研究 被引量:1
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作者 孙浩 郭迎清 李睿超 《航空计算技术》 2016年第1期123-126,130,共5页
发动机机载实时模型稳态基准值反映了当前发动机的工况,决定着实时模型的稳态精度。提出一种利用传感器测量数据修正机载实时模型稳态基准值的方法,具体采用多项式线性拟合技术、利用传感器近期测量数据修正机载实时模型的基准值,以适... 发动机机载实时模型稳态基准值反映了当前发动机的工况,决定着实时模型的稳态精度。提出一种利用传感器测量数据修正机载实时模型稳态基准值的方法,具体采用多项式线性拟合技术、利用传感器近期测量数据修正机载实时模型的基准值,以适应发动机稳态特性的改变、提高模型稳态精度。针对某民用大涵道比涡扇发动机构建的在线故障诊断仿真系统研究表明,在发动机发生性能退化的情况下,修正后的机载实时模型的稳态误差降低近1.8%。 展开更多
关键词 航空发动机 机载系统 实时模型 基准 模型修正
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基于瞬态基准实验的CAACS程序验证
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作者 于淼 刘国明 +3 位作者 霍小东 易璇 杨海峰 邵增 《核科学与工程》 CSCD 北大核心 2017年第6期1066-1070,共5页
核临界安全是核工业发展的特殊安全问题,其中临界事故的分析评价具有重要的学术意义和工程价值。CAACS程序是自主开发的圆柱形溶液系统临界事故分析程序,可以实现计算临界事故的裂变次数,裂变功率、温度随时间的变化等功能。为了验证自... 核临界安全是核工业发展的特殊安全问题,其中临界事故的分析评价具有重要的学术意义和工程价值。CAACS程序是自主开发的圆柱形溶液系统临界事故分析程序,可以实现计算临界事故的裂变次数,裂变功率、温度随时间的变化等功能。为了验证自主开发的CAACS程序,本文利用瞬态基准实验对程序进行验证,并于其他程序作了对比。结果表明:CAACS程序的计算结果与实验测量值符合较好,与国外同类程序具有相当的技术水平和精度,可为后处理厂建设提供事故分析的技术手段,为后续的临界瞬态研究奠定基础。。 展开更多
关键词 CAACS 溶液系统 临界事故 程序验证 基准实验
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超声波场强化解吸的机理分析 被引量:18
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作者 郭平生 华贲 李忠 《高校化学工程学报》 EI CAS CSCD 北大核心 2002年第6期614-620,共7页
在定域吸附的假定条件下,从能量的角度出发,由统计热力学理论得到了有外场作用的吸附平衡关系式。由此进一步讨论了超声波场强化解吸的机理,得到了在超声波场中吸附相分子比基准态分子获得更多的能量是导致吸附平衡等温线降低, 即强化... 在定域吸附的假定条件下,从能量的角度出发,由统计热力学理论得到了有外场作用的吸附平衡关系式。由此进一步讨论了超声波场强化解吸的机理,得到了在超声波场中吸附相分子比基准态分子获得更多的能量是导致吸附平衡等温线降低, 即强化解吸的主要原因。由于超声波的“聚能效应”使得吸附相分子比基准态分子能够获得更多的能量,这正是超声波对固液吸附系统能够强化解吸的本质所在,其理论研究与实验结果一致。研究结果还表明, 吸附相分子在超声波场中只要获得可与kT比拟或更高的能量,解吸效果就会明显,这体现了强化解吸中超声波场与温度场之间的协同作用。 关键词:能量公设;非热效应; 展开更多
关键词 超声波场强化解吸 机理 能量公设 非热效应 吸附平衡 场协同 基准态 聚能效应 吸附 分离
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输变电设备智能化运维系统研究与应用 被引量:22
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作者 李穆 卢文华 向冬冬 《电气工程学报》 2015年第7期71-77,共7页
针对输变电设备的运维管理工作,利用安全生产管理信息系统、电力GIS地理信息系统和EMS能量管理系统等业务系统,在其之上建立了一套输变电设备智能化运维系统。通过打破各业务系统的信息孤岛,提出了一种设备基准态分析方法评价设备的健... 针对输变电设备的运维管理工作,利用安全生产管理信息系统、电力GIS地理信息系统和EMS能量管理系统等业务系统,在其之上建立了一套输变电设备智能化运维系统。通过打破各业务系统的信息孤岛,提出了一种设备基准态分析方法评价设备的健康程度,并从设备重要度和健康度两个角度对设备进行管控分级。采用基于案例与基于规则的推理算法进行故障预测,确定设备故障模式。最终利用状态评价、风险评估、监测预警和故障预测模块的结果,给出差异化的运维建议。本系统通过某例变压器的诊断分析结果,证明了该系统能够为输变电设备提供科学、准确的诊断和决策建议。 展开更多
关键词 基准态分析 管控分级 推理诊断 差异化运维
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基于有色噪声模型的GPS速度场精度与时间序列长度相关性研究 被引量:5
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作者 张风霜 畅柳 《地震》 CSCD 北大核心 2017年第1期92-102,共11页
利用2010—2015年陆态网络GPS连续观测站的三维站坐标时序资料,在采用最大似然估计MLE方法计算得到云南地区GPS基准站三维站坐标分量最优噪声模型的基础上,进一步定量对比分析了有色噪声和白噪声模型下陆态网络GPS连续站速度场稳定性与... 利用2010—2015年陆态网络GPS连续观测站的三维站坐标时序资料,在采用最大似然估计MLE方法计算得到云南地区GPS基准站三维站坐标分量最优噪声模型的基础上,进一步定量对比分析了有色噪声和白噪声模型下陆态网络GPS连续站速度场稳定性与时间序列长度的关系。结果表明:在闪烁噪声模型下,中国大陆大部分地区GPS连续站1a时段的速度不确定度大。而随着时间的逐年累积,闪烁噪声模型下的速度不确定度与同时段白噪声模型下的差异逐步减小,闪烁噪声模型下3~4a时段的速度不确定度与同时段白噪声模型的差异小于0.2mm。研究说明在有色噪声模型下要获得高精度的速度场需要3~4a的观测数据,白噪声模型下GPS速度场精度可靠可信的前提是采用不少于3~4a的数据。 展开更多
关键词 GPS时间序列 噪声分析 极大似然估计 网络GPS基准
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酸碱滴定误差公式的探讨
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作者 王仰明 《榆林学院学报》 1996年第3期31-36,共6页
关于酸碱滴定误差公式推导的资料很多,有的用文字叙述方法,一般概念摸糊,效果欠佳;有的用公式推导,从理论方面做到了准确,但很繁烦、本文用简明的方法可导出各种类型的滴定误差公式.
关键词 滴定误差 化学计量点 基准态物质
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Quadratic Radical Function Better Than Fisher z Transformation 被引量:2
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作者 杨正瓴 段志峰 +3 位作者 王晶晶 王腾 宋延文 张军 《Transactions of Tianjin University》 EI CAS 2013年第5期381-384,共4页
A new explicit quadratic radical function is found by numerical experiments,which is simpler and has only 70.778%of the maximal distance error compared with the Fisher z transformation.Furthermore,a piecewise function... A new explicit quadratic radical function is found by numerical experiments,which is simpler and has only 70.778%of the maximal distance error compared with the Fisher z transformation.Furthermore,a piecewise function is constructed for the standard normal distribution:if the independent variable falls in the interval(-1.519,1.519),the proposed function is employed;otherwise,the Fisher z transformation is used.Compared with the Fisher z transformation,this piecewise function has only 38.206%of the total error.The new function is more exact to estimate the confidence intervals of Pearson product moment correlation coefficient and Dickinson best weights for the linear combination of forecasts. 展开更多
关键词 normal distribution cumulative distribution function error function confidence interval correlation coefficient combination of forecasts
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汽轮发电机导风环与风扇基座碰摩原因及处理 被引量:3
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作者 沈国栋 陈宇 夏博文 《中国设备工程》 2014年第12期48-49,共2页
针对秦山二期核电站汽轮发电机导风环与转子风扇基座存在摩擦问题,根据分析和测量的结果,采取了相应的措施,消除了发电机动静部分碰摩问题。
关键词 金属粉末 碰摩 热膨胀 收缩 基准 轴向间隙
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Preliminary aquatic life criteria development and ecological risk assessment of ammonia in seven major river basins in China
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作者 WANG Yi-zhe YAN Zhen-guang +3 位作者 ZHENG Xin ZHAO Ying ZHANG Ya-hui YANG Ni-yun 《Marine Science Bulletin》 CAS 2016年第1期55-68,共14页
Ammonia is one of the basin indices which are nation-controlled in the waterenvironmental management. In order to assess the differences of ammonia criteria indifferent basins, 7 major basins are used for the study ob... Ammonia is one of the basin indices which are nation-controlled in the waterenvironmental management. In order to assess the differences of ammonia criteria indifferent basins, 7 major basins are used for the study object, including Songhua River,Liaohe River, Haihe River, Yellow River, Huaihe River, Yangtze River and ZhujiangRiver, referring the water environmental criteria technology of the United StatesEnvironmental Protection Agency, based on the effects of water characteristics on theecotoxicity of ammonia, and in summer and non-summer situation, aquatic life criteriais derived for ammonia. The results showed that: (a) The differences between thecriteria values in different basins and different seasons were significant. The differencesbetween the criteria values in different basins were greater than 6 times, while those indifferent seasons in the same basin were greater than 2 times. (b) The summer acuteand chronic criteria for Huaihe River were 0.37 mg/L and 0.06 mg/L while thenon-summer values were 0.81 mg/L and 0.15 mg/L. Both the summer and thenon-summer values were lowest in all of the seven basins. (c) The preliminaryassessment of Ammonia exposure ecological risk indicated that was the lowest inZhujiang River, and it was much lower in Songhua River, Liaohe River and YangtzeRiver, and was higher in Yellow River, and the highest in both Haihe River and HuaiheRiver. Haihe River has 7 sections while 2 in high risk, and Huaihe River has 27 sectionswhile sixteen in high risk. According to the differences of the criteria values for ammoniain seven basins in different seasons and difference of ammonia ecological riskassessment, it is suggested that it should be managed by different policies. 展开更多
关键词 seven basins AMMONIA aquatic life criteria ecological risk assessment risk quotient
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Four-Parameter Scheme for Ground Level of Helium Atom
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作者 HU Xian-Quan XU Jie +1 位作者 MA Yong ZHENG Rui-Lun 《Communications in Theoretical Physics》 SCIE CAS CSCD 2006年第5期906-910,共5页
In this paper,the ground state wave function of four parameters is developed and expression of the ground state level is derived for the helium atom when the radial Schrodinger equation of the helium atom is solved. T... In this paper,the ground state wave function of four parameters is developed and expression of the ground state level is derived for the helium atom when the radial Schrodinger equation of the helium atom is solved. The ground energy is respectively computed by the optimized aJgorithms of Matlab 7.0 and the Monte Carlo methods. Furthermore, the ground state wave function is obtained. Compared with the experiment value and the value with the variation calculus in reference, the results of this paper show that in the four-parameter scheme, not only the calculations become more simplified and precise, but also the radial wave function of the helium atom meets the space symmetry automatically in ground state. 展开更多
关键词 helium atom ground state level variation calculus wave function
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Microscopic Study of Band Structures in^(98-102)Sr and^(100-104)Zr Isotopes
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作者 董国香 于少英 +1 位作者 刘艳鑫 沈彩万 《Communications in Theoretical Physics》 SCIE CAS CSCD 2011年第11期922-926,共5页
The properties of the high spin states of the neutron-rich 98-102Sr and 100-104Zr isotopes have been st udied using the projected shell model. In particular, the upbending phenomenon is investigated for these isotopes... The properties of the high spin states of the neutron-rich 98-102Sr and 100-104Zr isotopes have been st udied using the projected shell model. In particular, the upbending phenomenon is investigated for these isotopes along the yrast line. The results show that the occurrence of upbending phenomenon is attributed to the band crossing between ground state band and 2-qp neutron band having configuration 2vh11/2[-3/2, 5/2], K = 1. Furthermore, the neutron two-quasi-particle structure of side bands in 98SR-102Zr is discussed in this paper. 展开更多
关键词 projected shell model yrast band upbending side band
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Stable response of axisymmetric two-phase water-saturated soil 被引量:6
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作者 蔡袁强 孟楷 徐长节 《Journal of Zhejiang University Science》 EI CSCD 2004年第9期1022-1027,共6页
Biot's dynamic consolidation equations and Hankel transform were used to derive the integral solutions of stress and displacement for axisymmetric harmonic excitations in the two-phase saturated soil with subjacen... Biot's dynamic consolidation equations and Hankel transform were used to derive the integral solutions of stress and displacement for axisymmetric harmonic excitations in the two-phase saturated soil with subjacent rock-stratum. The influence of the coefficient of permeability and loading frequency on the soil displacement at the ground surface were studied. The results showed that higher loading frequency led to more dynamic characteristics; and that the effect of the soil permeability was more obvious at higher frequencies. 展开更多
关键词 Biot's dynamic consolidation Lamb's problem Saturated subsoil
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偶偶核结构相变的微观相互作用玻色子模型方案的分类与特征 被引量:1
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作者 汪红 石筑一 +1 位作者 童红 杨亚碧 《四川大学学报(自然科学版)》 CAS CSCD 北大核心 2012年第5期1060-1066,共7页
本文基于相互作用玻色子模型的微观方案,探讨了从自由价核子到构建出Arima哈密顿量的两次结构突变:核子配对成理想玻色子(玻色化)和理想玻色子集体化(有序化),据此将原子核相变划分为基准态重组型和玻色子破对型两类.最后,讨论了微观相... 本文基于相互作用玻色子模型的微观方案,探讨了从自由价核子到构建出Arima哈密顿量的两次结构突变:核子配对成理想玻色子(玻色化)和理想玻色子集体化(有序化),据此将原子核相变划分为基准态重组型和玻色子破对型两类.最后,讨论了微观相互作用玻色子模型研究原子核相变的特点与不足. 展开更多
关键词 偶偶核 微观IBM方案 原子核相变 基准态重组型相变 玻色子破对型相变
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Correction method for non-landing measuring of vehicle-mounted theodolite based on static datum conversion 被引量:6
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作者 LIU JinBo ZHANG XiaoHu +3 位作者 LIU HaiBo YUAN Yun ZHU ZhaoKun YU QiFeng 《Science China(Technological Sciences)》 SCIE EI CAS 2013年第9期2268-2277,共10页
During the non-landing measuring of vehicle mounted theodolite, especially under high-speed tracking measurement, the misalignment of theodolite's center of mass and spindle etc. will cause high-frequency vibratio... During the non-landing measuring of vehicle mounted theodolite, especially under high-speed tracking measurement, the misalignment of theodolite's center of mass and spindle etc. will cause high-frequency vibration of theodolite platform, increase the observation error of targets and even unbelievable results. In this paper, a correction method of non-landing measuring of theodolite based on static datum conversion is presented, which can effectively improve the observation accuracy of theodolite. The CCD camera is fixed to the theodolite platform to calculate the gesture shaking quantity of theodolite platform in geodetic coordinate system through the real time imaging of static datum. The observation results of theodolite are corrected by using such shaking quantity. The experiment shows that the correction accuracy exceeds 10 s of arc. The intrinsic parameter calibration technology of camera based on stellar angular distance and absolute conic put forward in this paper can prevent the estimated error of extrinsic parameters influencing the intrinsic parameter calibration and improve the intrinsic parameter calibration accuracy; the static datum conversion technology can reduce the influence of installation error of camera and theodolite platform on gesture measuring of the platform. The simulation experiment shows that when the shaking range of the platform is less than 30 min of arc, the influence of the three-axis installation error of camera within 3deg on the accuracy of correction results is less than 8 s of arc. The method in this paper can be extended to and used in the field of gesture shaking measuring and micro-structure deformation of various unstable platforms, therefore it is of important theoretical research significance and has wide engineering application prospect. 展开更多
关键词 vehicle-mounted theodolite non-landing Measuring error correction static datum conversion decoupling calibration
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A Lagrange-multiplier-based XFEM to solve pressure Poisson equations in problems with quasi-static interfaces 被引量:1
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作者 LIAO JianHui ZHUANG Zhuo 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2012年第4期693-705,共13页
The XFEM(extended finite element method) has a lot of advantages over other numerical methods to resolve discontinuities across quasi-static interfaces due to the jump in fluidic parameters or surface tension.However,... The XFEM(extended finite element method) has a lot of advantages over other numerical methods to resolve discontinuities across quasi-static interfaces due to the jump in fluidic parameters or surface tension.However,singularities corresponding to enriched degrees of freedom(DOFs) embedded in XFEM arise in the discrete pressure Poisson equations.In this paper,constraints on these DOFs are derived from the interfacial equilibrium condition and introduced in terms of stabilized Lagrange multipliers designed for non-boundary-fitted meshes to address this issue.Numerical results show that the weak and strong discontinuities in pressure with straight and circular interfaces are accurately reproduced by the constraints.Comparisons with the SUPG/PSPG(streamline upwind/pressure stabilizing Petrov-Galerkin) method without Lagrange multipliers validate the applicability and flexibility of the proposed constrained algorithm to model problems with quasi-static interfaces. 展开更多
关键词 XFEM pressure Poisson equation SINGULARITY Lagrange multiplier quasi-static flows
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Design and implementation of a platform for configuring clinical dynamic safety checklist applications
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作者 Shan NAN Xu-dong LU +4 位作者 Pieter VAN GORP Hendrikus H.M.KORSTEN Richard VDOVJAK Uzay KAYMAK Hui-long DUAN 《Frontiers of Information Technology & Electronic Engineering》 SCIE EI CSCD 2018年第7期937-946,共10页
In recent years, it has been demonstrated that checklists can improve patient safety significantly. To facilitate the effective use of checklists in daily practice, both the medical community and the informatics commu... In recent years, it has been demonstrated that checklists can improve patient safety significantly. To facilitate the effective use of checklists in daily practice, both the medical community and the informatics community propose to implement checklists in dynamic checklist applications that can be integrated into the clinical workflow and that is specific to the patient context. However, it is difficult to develop such applications because they are tightly intertwined with the content of specific checklists. We propose a platform that enables access to dynamic checklist applications by configuring the infrastructures provided in the platform. Then, the applications can be developed without time-consuming programming work. We define a number of design criteria regarding point of care and clinical processes by analyzing the existing checklist applications and the lessons learned from implementations.Then, by applying rule-based clinical decision support and workflow management technologies, we design technical mechanisms to satisfy the design criteria. A dynamic checklist application platform is designed based on these mechanisms. Finally, we build a platform in various design cycle iterations, driven by multiple clinical cases. By applying the platform, we develop nine comprehensive dynamic checklist applications with 242 dynamic checklists.The results demonstrate both the feasibility and the overall generic nature of the proposed approach. We propose a novel platform for configuring dynamic checklist applications. This platform satisfies the general requirements and can be easily configured to satisfy different scenarios in which safety checklists are used. 展开更多
关键词 CHECKLIST WORKFLOW Clinical decision support Process management Patient safety
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