Real-time reliability evaluation based on damaged measurement degradation data

A method was proposed to evaluate the real-time reliability for a single product based on damaged measurement degradation data.Most researches on degradation analysis often assumed that the measurement process did not have any impact on the product's performance.However,in some cases,the measurement process may exert extra stress on products being measured.To obtain trustful results in such a situation,a new degradation model was derived.Then,by fusing the prior information of product and its own on-line degradation data,the real-time reliability was evaluated on the basis of Bayesian formula.To make the proposed method more practical,a procedure based on expectation maximization (EM) algorithm was presented to estimate the unknown parameters.Finally,the performance of the proposed method was illustrated by a simulation study.The results show that ignoring the influence of the damaged measurement process can lead to biased evaluation results,if the damaged measurement process is involved.

Belief reliability:a scientific exploration of reliability engineering

This paper systematically introduces and reviews a scientific exploration of reliability called the belief reliability.Beginning with the origin of reliability engineering,the problems of present theories for reliability engineering are summarized as a query,a dilemma,and a puzzle.Then,through philosophical reflection,we introduce the theoretical solutions given by belief reliability theory,including scientific principles,basic equations,reliability science experiments,and mathematical measures.The basic methods and technologies of belief reliability,namely,belief reliability analysis,function-oriented belief reliability design,belief reliability evaluation,and several newly developed methods and technologies are sequentially elaborated and overviewed.Based on the above investigations,we summarize the significance of belief reliability theory and make some prospects about future research,aiming to promote the development of reliability science and engineering.

Accurate measurement and influence on device reliability of defect density of a light-emitting diode

A method of accurately measuring the defect density of a high-power light-emitting diode （LED） is proposed. The method is based on measuring the number of emitting photons in the magnitude of 105 under the injection current as weak as nA and calculating the non-radiative recombination coefficient which is related to defect density. Defect density is obtained with the self-developed measurement system, and it is demonstrated that defect density has an important influence on LED optical properties like luminous flux and internal quantum efficiency （IQE）. At the same time, a batch of GaN-based LEDs with the chip size of 1 minx 1 mm are selected to conduct the accelerated aging tests lasting for 1000 hours. The results show that defect density exhibits a greater variation and is more sensitive to LED reliability than luminous flux during aging tests. Based on these results, it is concluded that for the GaN-based LED with a chip size of 1 mm ~ I mm, if its defect density is over 1017/cm3, the LED device performance suffers a serious deterioration, and finally fails.

A Bootstrapping Approach for Software Reliability Measurement Based on a Discretized NHPP Model

Discrete software reliability measurement has a proper characteristic for describing a software reliability growth process which depends on a unit of the software fault-detection period, such as the number of test runs, the number of executed test cases. This paper discusses discrete software reliability measurement based on a discretized nonhomogeneous Poisson process (NHPP) model. Especially, we use a bootstrapping method in our discrete software reliability measurement for discussing the statistical inference on parameters and software reliability assessment measures of our model. Finally we show numerical examples of interval estimations based on our bootstrapping method for the several software reliability assessment measures by using actual data.

Applied research on reliable increase measures of CNC lathes

According to the reliable data of sixteen CNC lathes, each reliable index of the serial CNC lathes is evaluated before tackling and after tackling. According to the failure analysis, reliable improvement measures of the serial CNC lathes are put forward.

Reliability of a Novel Cobb Protractor for Measuring the Cobb Angle of Radiograph in Scoliosis

Objective To introduce a novel Cobb protractor and assess its reliability and rapidity for measuring Cobb angle in scoliosis patients. Methods The novel Cobb protractor had two endplate markers. A measurement was performed just to align the two markers to each endplate of the curve. The Cobb angle on the posteroanterior radiographs of 24 patients clinically diagnosed with adolescent idiopathic scoliosis was measured by three orthopedic surgeons with both standard Cobb method and the new technique, and the time of measurement was recorded. Intraclass correlation coefficients(ICCs) were calculated to assess the reliability of the new method. Results The time for a measurement with the new tool was approximately 10 seconds less than the time that used to finish a measurement with the standard method(P<0.05). The overall mean Cobb angle for the major curve of the 24 patients was 47.8°. The mean overall intraobserver and interobserver ICC was 0.971 and 0.971 for the Cobb method group, while the overall intraobserver ICC and the interobserver was 0.985 and 0.979 for the new tool group. Conclusions The novel Cobb protractor could perform quick measurement and measure almost all forms of radiographs. The Cobb protractor might be an ideal instrument to measure the Cobb angle.

Optical Measurement System for Motion Characterization of Surface Mount Technology

Advanced testing methods for the dynamics of mechanical microdevices are necessary to develop reliable, marketable microelectromechanical systems. A system for measuring the nanometer motions of microscopic structures has been demonstrated. Stop-action images of a target have been obtained with computer microvision, microscopic interferometry, and stroboscopic illuminator. It can be developed for measuring the in-plane-rigid-body motions, surface shapes, out-of-plane motions and deformations of microstructures. A new algorithm of sub-pixel step length correlation template matching is proposed to extract the in-plane displacement from vision images. Hariharan five-step phase-shift interferometry algorithm and unwrapping algorithms are adopted to measure the out-of-plane motions. It is demonstrated that the system can measure the motions of solder wetting in surface mount technology(SMT).

Characteristics of Integrated Importance Measure for Whole Lifetime-Oriented System Performance Evaluation

Importance measures are being widely used to characterize the importance of component in systems.Focus on the integrated importance measure(IIM)of the whole lifetime measure based on the transition rates of component states.To describe the impact of each component in whole lifetime,the IIM is generalized in nonrepairable and repairable systems at first.Then,their formulas are computed in series and parallel systems.Finally,the characteristics of generalized IIM in typical series systems and parallel systems are analyzed.The results show that the generalized IIM of component can evaluate the expected effect of component state on the system performance in whole lifetime.

Measurements and analysis at 400MHz and 2600MHz in corridor radio channel

A propagation measurement campaign was performed at the 10 th floor corridor of Xingjian Building,Shanghai University,China.The channel was sounded by pseudo noise( PN) sequence at carrier frequencies of 400-and 2600-MHz respectively.In order to obtain large scale and small scale propagation characteristics in the corridor,the receiver was moved along the corridor every 1.02 meter to record the impulse response.More than 280,000 impulse responses were recorded in the campaign.This work first describes the principle of the measurement,and then how the recorded raw data are processed.The results show that path loss exponent is related to frequency.The relationship between the root-mean squared( RMS) delay spread and the T-R separation distance is analyzed.The RMS delay spread and the mean excess delay spread against path loss are also given,which explain why the 2600 MHz RMS delay spread is larger than that of 400 MHz.

Recursive Fourier Method and Its Application to AC Measurement

The Modified Recursive Fourier Meth(MRFM) is presented here and applied to DISA series integrated substation automation systems for AC measurement comparing with the other measure methods used in RTUs. The application shows its high accuracy, good real time response. And it can measure harmonic in real bine.

Lognormal Process Software Reliability Modeling with Testing-Effort

We propose a software reliability growth model with testing-effort based on a continuous-state space stochastic process, such as a lognormal process, and conduct its goodness-of-fit evaluation. We also discuss a parameter estimation method of our model. Then, we derive several software reliability assessment measures by the probability distribution of its solution process, and compare our model with existing continuous-state space software reliability growth models in terms of the mean square error and the Akaike’s information criterion by using actual fault count data.

海事卫星地面站RMS可用性评估模型

随着国际海事卫星通信系统(international maritime satellite communication system,INMARSAT)的不断发展,卫星地面站(satellite earth station,SES)的可用性评估具有重要意义。首先选取可靠性、维修性和保障性为指标,构建可靠性、维修性与保障性(reliability,maintainability and supportability,RMS)模型进行SES可用性评估;其次,以SES设备为研究对象,根据马尔可夫链得到设备有效性概率,并进一步推导出系统可靠性;然后,建立排队图解协调技术(queue-graphical evaluation and review technique,Q-GERT)网络以描述SES设备的维修保障过程,并基于AnyLogic软件进行建模仿真;最后,通过算例进行应用研究,基于RMS模型进行SES可用性评估,验证了该模型和评估方法的有效性与实用性。

An Uncertainty Analysis and Reliability-Based Multidisciplinary Design Optimization Method Using Fourth-Moment Saddlepoint Approximation

In uncertainty analysis and reliability-based multidisciplinary design and optimization(RBMDO)of engineering structures,the saddlepoint approximation(SA)method can be utilized to enhance the accuracy and efficiency of reliability evaluation.However,the random variables involved in SA should be easy to handle.Additionally,the corresponding saddlepoint equation should not be complicated.Both of them limit the application of SA for engineering problems.The moment method can construct an approximate cumulative distribution function of the performance function based on the first few statistical moments.However,the traditional moment matching method is not very accurate generally.In order to take advantage of the SA method and the moment matching method to enhance the efficiency of design and optimization,a fourth-moment saddlepoint approximation(FMSA)method is introduced into RBMDO.In FMSA,the approximate cumulative generating functions are constructed based on the first four moments of the limit state function.The probability density function and cumulative distribution function are estimated based on this approximate cumulative generating function.Furthermore,the FMSA method is introduced and combined into RBMDO within the framework of sequence optimization and reliability assessment,which is based on the performance measure approach strategy.Two engineering examples are introduced to verify the effectiveness of proposed method.

三维度生命意义感量表的中文版翻译及其信效度检验

引入三维度生命意义感量表(Three Dimensional Meaning in Life Scale,3DM),包含目标、重要性和一致性3个维度,检验其中文翻译版的信效度和测量等值性。样本1(544名大学生)用于探索性因素分析,样本2(559名成年人)用于验证性因素分析和测量等值性检验。选取生命意义感问卷作为效标效度,正性负性情绪量表和生活满意度量表作为聚合–区分效度。间隔1个月,对345人进行重测,考察重测信度。结果表明,探索性和验证性因素分析支持三维度结构,总量表及分量表的内部一致性系数在0.82~0.95之间,重测信度在0.71~0.83之间。3DM量表总分及分维度与拥有意义感、寻求意义感、正性情绪和生活满意度显著正相关,与负性情绪显著负相关。3DM量表具有跨性别与跨时间的测量等值性。研究结果证明,3DM量表具有良好的信效度,可以在中国用于测量生命意义感的不同成分。

中国青少年社会与情感能力第二轮测评技术报告

本技术报告基于中国济南参加2023年社会与情感能力(Survey on Social and Emotional Skills,SSES)的测评数据,对第二轮测评工具在中国文化下的心理测量学特征进行分析。本报告简要介绍了学生问卷的开发和实施过程、社会与情感能力指标体系、问卷主要组成部分、数据集的主要内容,并对数据质量进行了分析。分析结果表明,济南参试学生参试态度认真积极,参试率和有效应答率高,但是10岁组产生了高分翘尾现象;采用ω系数和α系数来衡量分量表的信度,结果表明绝大多数分量表信度良好;运用验证性因子分析逐一检验社会与情感能力各个分量表的效度,发现拟合度较为满意;多组验证性因子分析表明,这些分量表跨性别测量等值性好于跨年龄组等值性,故在考察青少年社会与情感子能力的年龄差异时,对于等值性较差的分量表数据应慎重使用。

基于“四象限模型”的医患信任测量量表构建及初步研究

目的 通过构建适宜我国应用的“四象限模型”医患信任测量量表,评价分析其效度及信度,为改善医患关系提供一定的帮助。方法 本文以国外学者研究的“四象限模型”为理论框架,通过文献回顾、访谈法、德尔菲专家咨询法等多种方式构建“四象限模型”医患信任测量量表,将某院作为实际研究的案例,对“四象限模型”医患信任测量量表的信度、效度进行检验。结果 “四象限模型”医患信任测量量表的总Cronbach’s α信度系数为0.912;分半信度R为0.863和0.932;内容效度Pearson相关系数0.38~0.81,均具有统计学意义;结构效度RMR为0.065,RMSEA为0.073,χ~2/df为2.236,GFI为0.791。结论 经过某医院的实证检验,“四象限模型”医患信任测量量表具有较高的信度和较好的效度,可为我国医患信任方面研究提供一个科学的、合理的、有效的并且符合我国国情的医患信任测量量表,在重构医患信任、改善医患关系方面有着广阔的应用前景。

基于蒙特卡洛仿真的航空用测控装置可靠性预计

文章研究了某面向航空应用的高可靠性测控装置的可靠性预计问题。根据测控装置设计原理图建立了可靠性框图,基于GJB/Z299C手册和应力分析法得到了元器件可靠性数据,建立了基于蒙特卡洛仿真方法的系统可靠性预计数学模型,预计了测控装置的可靠性指标,并通过分析查找可靠性薄弱环节,改进了设计方案,提高了可靠性,最终达到设计要求。文章研究表明,蒙特卡洛仿真方法对于混连复杂电子系统的可靠性预计具有较好的实用性。

肾结石患者报告结局测评量表的汉化及信效度检验

目的 汉化剑桥肾结石患者报告结局(PRO)测评量表(CReSP),并对其进行信效度检验,以期为临床评估肾结石PRO提供特异性量表。方法 对原量表进行翻译-回译-跨文化调试-预实验,形成中文版量表。于2021年8月-2022年4月选取我院420例肾结石患者作为研究对象进行调查研究,验证量表的信效度。结果 中文版CReSP共包括6个维度、14个条目。量表各条目的内容效度指数为0.80~1.00,量表内容效度指数为0.79;提取公因子共6个,方差累计贡献率为78.602%;Promax斜交旋转后各条目因子载荷量为0.650~0.989,验证性因子分析结果显示模型适配度良好。量表及各个维度Cronbach′s α系数为0.859~0.959;其重测信度为0.804~0.941。结论 中文版CReSP具有良好的信效度,可作为肾结石PRO的特异性评价工具。

桑皮勒水电站高程测量成果验证方法研究

介绍了水利工程高程测量的方法及GPS高程转换原理,并针对高海拔、大高差、通行条件差的地区水利工程水准测量成果难以复测及验证的问题,提出了采用GPS大地高进行转换获得水准点的正常高及高差用于验证水准测量成果可靠性的方法。工程应用结果表明,该水准测量成果可靠,不存在粗差,同时也说明了EGM2008在新疆西部高山区达不到其标称的全球精度,也达不到在我国内地地区的总体精度20 cm,但可以用联测已知高程点的方法消除系统差后用于水准粗差探测及精度要求不高的高程传递。

直升机RMS与测试性综合评估模型研究

通过对直升机可用性,可靠性、维修性、保障性(reliability&maintainability&supportability,RMS)和测试性的研究,提出对可用性进行综合评估,并说明在RMS基础上考虑测试性的必要性。首先,根据RMS与测试性的常用参数,建立了可用性综合评估指标体系;其次,在现有多种综合评估方法中,选择模糊层次分析法(即层次分析法(analytic hierarchy process,AHP)与模糊综合评估法(fuzzy comprehensive evaluation,FCE)相结合的方式)对直升机可用性进行评估,从而构建了总体综合评估模型;最后,应用Matlab平台对提出的评估模型进行仿真,并以直11型直升机为例对提出的方法进行验证,实现了评估的自动化与可视化。