Probabilistic Analysis of a Robot System with Redundant Safety Units and Common-Cause Failures

This paper presents reliability and availability analyses of a model representing a system having one robot and n-redundant safety units with common-cause failures. At least k safety units must function successfully for the robot system success. The robot and other failure rates and the partially failed system repair rates are assumed constant and the failed robot-safety system repair time is assumed arbitrarily distributed. Markov and supplementary variable methods were used to perform mathematical analysis of this model. Generalized expressions for state probabilities, system availabilities, reliability, mean time to failure, and variance of time to failure are developed. Plots of some resulting expressions are shown.

The Study for the Causes of Pragmatic Failure

This paper,based on the questionnaire,deduces the causes of pragmatic failure which are summarized into four:The different value orientation between the two cultures,consisting individualism versus collectivism,power distance,connotation versus denotation,and orientation towards time,negative transfer of equivalent structures and behaviors,insufficient or improper teaching and the scarcity of universal knowledge for communication.

A hospital based study on causes peculiar of congestive cardiac failure(CCF)

Objective:To determine the frequency of risk factors of congestive cardiac failure in a tertiary care hospital of Peshawar.Methods:This retrospective observational study was conducted in department of Cardiology,Postgraduate Medical Institute,Lady Reading Hospital Peshawar,from March 2005 to September 2007.Relevant information regarding the risk factors of congestive cardiac failure were recorded on questionnaire prepared in accordance with the objectives of the study.Results:1 019 patients with established diagnosis of cardiac failure (based on clinical findings and relevant investigations) were included.Out of total sampling 583 (57.12%) were males and 436(42.78%) were females.The age range of the patients was from 6 years to 82 years with mean age of 48.5 years and mode of age was 45 years.The distribution of causative factors of CCF was:ischemic heart disease(IHD) 36.31%,hypertension 26.30%,dilated cardiomyopathy 10.10%,obstructve and restrictive cardiomyopathies 5.39%,valvular heart diseases(VHD) 9.32%,congenital heart disease like ventricular septal defects(VSD) 4.41%,atrial septal defects(ASD) 0.58%,atrial fibrillation (AF) 2.25%,constrictive pericardidtis 1.07%.Pericardial effusion 0.68%,chronic obstructive pulmonary disease and pulmonary hypertension 1.47%,thyrotoxicosis 0.68%,complete heart block 0.29%and paget disease in 0.09%cases.Conclusion:Ischemic heart disease,hypertension,cardiomypathies,valvular heart disease and congenital heart disease are major contributor to CCF in our patients.

Analysis of Potential Causes of Safety Failure of New Energy Vehicle Power Batteries

The aim of this paper is to analyze the potential reasons for the safety failure of batteries for new-energy vehicles.Firstly,the importance and popularization of new energy batteries are introduced,and the importance of safety failure issues is drawn out.Then,the composition and working principle of the battery is explained in detail,which provides the basis for the subsequent analysis.Then,the potential impacts of factors such as overcharge and over-discharge,high and low temperature environments,internal faults,and external shocks and vibrations on the safety of the batteries are analyzed.Finally,some common safety measures and solutions are proposed to improve the safety of new energy batteries,in hopes of improving the safety of batteries for new-energy vehicle.

慢性心力衰竭患者社会衰弱现状及其影响因素可解释性分析研究

背景心力衰竭(简称心衰)合并衰弱的综合管理对衰弱评估提出了多维需求,然而作为心衰患者不良健康结局的增量预测因子,衰弱的社会维度尚未得到充分关注。目的分析慢性心衰患者社会衰弱现状及其影响因素。方法采用便利抽样法,选取2022年9月—2023年7月在南京医科大学第一附属医院心血管内科住院治疗的慢性心衰患者作为调查对象。采用一般资料调查表、社会衰弱量表(HALFT量表,评估社会衰弱)、中文简化版孤独感量表(评估孤独感)、简化版双向社会支持量表(评估社会支持)、个人掌控感量表(PMS,评估个人掌控感)、患者健康问卷(PHQ-9,评估抑郁情况)进行调查。采用单因素分析、支持向量机-特征递归消除进行特征筛选,构建支持向量机分类模型,引入SHAP值进行影响因素分析。结果本研究筛选患者228例,其中8例拒绝填写,共计发放问卷220份,回收有效问卷213份,有效问卷回收率为96.81%。慢性心衰患者中社会衰弱前期及社会衰弱人数占比分别为46.0%(98/213)、17.8%(38/213)。不同社会衰弱情况的慢性心衰患者文化程度、居住地、工作状态、疾病经济负担、个人月收入、病程、运动习惯、就医满意度、交通出行、孤独感量表得分、简化版双向社会支持量表得分、PMS得分、PHQ-9得分比较,差异有统计学意义(P<0.05)。支持向量机-特征递归消除模型性能最佳时,采用最优特征子集(以3∶7拆分样本作为测试集和训练集)构建分类模型后进行SHAP值可解释性分析,模型预测准确率在训练集和测试集中分别为0.73和0.63,此时特征重要性排序及影响方向从高到低为无运动习惯(+)、个人掌控感(-)、疾病经济负担重(+)、双向社会支持(-)、抑郁(+)、孤独感(+)、无业(+)。结论慢性心衰患者中社会衰弱占60%以上,医护人员应对患者的社会功能予以重视,关注患者缺失的社会资源属性及其上游因素,通过强化外部支持系统、培养患者内在信念、克服负性情绪体验,统筹制订管理方案,整合医疗资源实施干预延缓或逆转患者社会衰弱进程,改善其预后及生活质量。

Causes and statistical characteristics of bridge failures:A review

Bridge failure, which is generally associated with serious economic and life losses, is defined as the incapacity of a constructed bridge or its components to perform as specified in the design and construction requirements. This paper presents an overview of current researches on the typical characteristics and causes of bridge failures based on 10 former investigations. Principal causes can be divided into internal causes and external causes or natural factors and human factors. Design error, construction mistakes, hydraulic, collision, and overload are the top 5 leading causes of bridge failures, resulting in more than70% of the bridge failures. Causes of bridge failures are closely related to regional economy,structural type, type of use, material type, and service age. The failure rate is very high for steel bridges, which is inseparable from excessive emphasis on structure strength but lack of consideration on structure stability and fatigue in early years. Researchers need to strengthen their research on the stability and fatigue of steel bridges, as well as inspection and maintenance. Extreme loads such as flood, collision, and overload contribute to a large number of bridge failures because of the lack of extreme loads data and design theory defects. It is critical for such bridges to have sufficient redundancy and capacity protection measures to reduce the probability of bridge failure due to extreme loads. Previous statistical methods and classification methods for the characteristics and causes of bridge failures lack unified standards, and a more scientific method needs to be established. A comprehensive electronic database on bridge damage and failures needs to be developed to establish damage models and conduct forensic studies to improve the design theory and specifications.

Reliability Analysis of Systems with Common Cause Failure Based on Stress-Strength Interference Model

Many mechanical systems have the characteristics of multiple failure modes and complex failure mech- anisms. On the basis of stress-strength interference （SSI） model, this paper takes the mechanical system with common cause failure （CCF） as the research object. The relationship between the stress distribution and the strength distribution is studied, and the failures of components are independent of each other under the determin- istic stress. Then, the concept of conditional reliability is introduced to build the system reliability models under the action of one-stress and multi-stress for both series and parallel systems. Finally, the corresponding properties of the DrODosed methods are discussed to show their advantages.

Reliability of IEC 61850 based substation communication network architecture considering quality of repairs and common cause failures

Mission-critical IEC 61850 system architectures are designed to tolerate hardware failures to achieve the highest reliability performance.Hence,multi-channel systems are used in such systems within industrial facilities to isolate machinery when there are process abnormalities.Inevitably,multi-channel systems introduce Common Cause Failure(CCF)since the subsystems can rarely be independent.This paper integrates CCF into the Markov reliability model to enhance the model flexibility to investigate synchronous generator intra-bay SCN architecture reliability performance considering the quality of repairs and CCF.The Markov process enables integration of the impact of CCF factors on system performance.The case study results indicate that CCF,coupled with imperfect repairs,significantly reduce system reliability performance.High sensitivity is observed at low levels of CCF,whereas the highest level of impact occurs when the system diagnostic coverage is 99%based on ISO 13849-1,and reduces as the diagnostic coverage level reduces.Therefore,it is concluded that the severity of CCF depends more on system diagnostic coverage level than the repair efficiency,although both factors impact the system overall performance.Hence,CCF should be con-sidered in determining the reliability performance of mission-critical communication networks in power distribution centres.

Fault Tree Analysis of Feeding Control System for Computer Numerical Control Heavy-Duty Horizontal Lathes with Multiple Common Cause Failure Groups

The lathes are basic machine tools for manufacturing cylindrical parts. In recent years, the DLseries computer numerical control(CNC) heavy-duty horizontal lathes(HDHLs) have been widely used in the transportation, energy and aviation industries. High availability of the CNC heavy-duty lathes is demanded to guarantee the efficiency and benefit of these manufacturing industries. As one of the key subsystems of the HDHLs, the feeding control system is studied in this paper on reliability modeling and reliability analysis. The fault tree analysis(FTA) method is used for reliability modelling of the feeding control system. Considering the multiple common cause failure groups(CCFGs) existing in the system, a modified beta factor parametric model is introduced to model the common cause failure(CCF) in system. The reliability of feeding control system is then obtained and the effect of CCF on the reliability of the whole system is studied as well.

基于数理统计和文本挖掘的埋地钢制燃气管道失效分析

近年来燃气管道事故频发,严重威胁周边人民群众生命财产安全。为准确认识埋地钢制燃气管道失效特征及致因,针对性开展风险管控,以某管道燃气公司2018—2021年共计1338条埋地钢制燃气管道失效记录为分析蓝本,采用数理统计方法分析失效总体趋势及管道敷设位置、压力等级、外防腐层类型、失效原因、管龄对应的失效特征;采用文本挖掘技术共计提取26项埋地钢制燃气管道潜在失效致因,通过词云可视化方式分析高频失效致因;构建失效致因共现网络探索不同致因之间的耦合关系,并根据特征向量中心性辨识主要失效致因。结果表明:中压庭院管道是风险管理的重点;腐蚀失效频次与管龄总体呈正相关,且从第4 a开始失效频次快速增长,在第19 a左右达到峰值;土壤腐蚀、防腐层破损、杂散电流、未安装阴极保护系统、管道服役年限较长、管体缺陷、防腐层老化和敷设环境发生变化是埋地钢制燃气管道失效主要致因,是风险管控的关键点。

基于Reason模型的SIF-Q260型电子小肠镜故障原因分析

根据武汉大学中南医院内窥镜中心SIF-Q260型小肠镜故障率高且维修成本高的情况,应用Reason模型,从环境影响、不安全监督、不安全行为前兆及不安全行为4个层面分析造成SIF-Q260小肠镜故障的原因,针对各个层面故障原因,从定期培训以规范内窥镜的洗消及使用、设置专人管理内窥镜并定期对内窥镜使用洗消的规范性进行监督及评价、完善内窥镜监管系统3方面拟定改进措施,堵住系统“漏洞”,为内窥镜质量控制措施的制定提供依据,可预防和减少内窥镜故障的发生。

汽车跑偏故障原因分析及解决方案

对造成汽车跑偏的故障原因进行了详细的分析,并针对各种影响因素提出相应的解决方案。

动车组列控车载子系统故障机理建模与分析

针对传统Petri网(P/T系统)无法根据后继标识确定系统失效部位的问题,采用着色Petri网(Colored Petri Net,CPN)建立动车组列控车载子系统的故障传播模型。首先,通过CPN与传统Petri网理论的对比说明采用CPN建模的可行性。其次,根据车载子系统的结构组成及工作模式建立故障树模型,并通过Petri网描述故障树逻辑门事件之间的逻辑关系,给出故障树的Petri网表示方法,建立车载子系统的P/T系统模型;进一步根据CPN理论确定托肯染色方法、权函数等模型参数,将P/T系统转化为着色网系统,并举例说明后继标识的计算规则。最后,通过与传统Petri网推理及故障识别过程的对比,证明了采用CPN分析系统故障机理的正确性及在故障识别过程中的高效性。所提方法可为车载子系统的故障识别提供一定依据。

2型糖尿病对冠心病伴HFpEF预后影响及因素分析

目的探讨2型糖尿病(T2DM)对冠心病伴射血分数保留心力衰竭(HFpEF)病人预后影响。方法采用病例对照研究方法,选取2021年8月—2023年1月在中国人民解放军第3201医院治疗的合并T2DM的冠心病伴HFpEF病人65例为观察组,同时以年龄、性别配比1∶2选取未合并T2DM的冠心病伴HFpEF病人130例为对照组,比较两组临床基线资料、实验室检查、超声心动图检查以及主要心血管不良事件(MACE)发生率等指标,分析影响MACE发生的危险因素。结果观察组血清甘油三酯(TG)、左室后壁厚度(LVPWD)和MACE发生率等均明显高于对照组(t=4.227、5.508,χ^(2)=10.543,P<0.05)。已发生MACE病人年龄、血清TG和N端脑钠肽的前体(NT-proBNP)含量及并发糖尿病构成比等均明显高于未发生者(t=4.855、5.590,Z=-3.432,χ^(2)=10.543,P<0.05)。Logistic回归分析显示,年龄(OR=2.748,95%CI=1.671~4.521)、NT-proBNP(OR=3.755,95%CI=2.025~6.962)和糖尿病(OR=2.428,95%CI=1.565~3.766)等变量是影响冠心病伴HFpEF病人发生MACE的危险因素(P<0.05)。结论T2DM并发冠心病伴HFpEF病人MACE发生率显著升高,T2DM是影响冠心病伴HFpEF病人不良预后的风险因素,临床应早期干预以降低MACE的发生。

基于震后复旧工程的断裂带区域轨道设计借鉴

针对兰新高铁震后轨道伤损评估及复旧工程设计无章可依且无经验可借鉴的情况,基于震后复旧工程设计,对断裂带区域轨道结构选型与设计有关经验进行分析。除大梁隧道F5断裂外,钢轨扭曲变形及扣件破坏主要发生在硫磺沟大桥上,是由地震荷载下桥梁支座螺栓剪断后梁体移位落梁,相邻梁体变形差异大引起。道床板存在局部1~2 m范围碎裂,主要与地震横波、纵波传递过程中的叠加有关。个别段落出现轨道不平顺超限的情况,主要是受线下基础类型和地质条件差异等因素影响。震后复旧工程应首先基于基准点的测设与平差开展区域性线形重构与拟合;断裂带区域轨道设防长度根据有砟轨道养护维修最小段落长度确定,不能满足震后轨道结构的调整需求,建议结合预估错位量及线路拟合范围、轨道调整能力综合确定;近断裂带区域无砟轨道建议采用无挡肩轨枕,在地震情况下使扣件弹条或者锚固螺栓发生破坏,而轨枕保持完整,以降低震后复旧工程难度及代价;为确保特殊条件下的整治效果,建议采取特种整治措施。

贵州晴隆红寨大型古滑坡复活变形特征及成因分析

2020年9月17日,贵州省晴隆县鸡场镇红寨村发生滑坡灾害,导致134栋房屋严重损毁,127户569人紧急避险。通过调查发现,红寨滑坡是一处规模达6.25×106 m^(3)的深层大型滑坡,地表房屋及基础设施破坏严重,但整个滑坡运动距离极短。通过对地形地貌和岩土体结构及物质成分组成的分析、水系变动判断及钻孔揭露的多层滑面等综合分析认为,红寨滑坡是一处顺层的复活古滑坡。为分析研究该滑坡的变形特征和复活成因,采用无人机航测、工程地质调查、岩土体勘查、地球物理勘探等手段,获取了详细的灾害发育特征、影响因素及古滑坡的辨识特征等数据。分析结果表明:红寨滑坡可根据变形破坏特征及应力传递方向分为A、B、C、D 4个分区,其中B区又根据相对滑移量分为B1、B2亚区;滑坡的变形复活是在高陡的地形地貌、复杂的岩体结构、软弱的工程岩组和持续地表水入渗等共同作用下发生的;滑坡后缘圈椅状地形、滑体与周围岩土体的物质差异、断层切割前缘及水系堆积物的变迁等多方面特征验证了古滑坡的事实。

基于医疗失效模式与效应分析框架的社区2型糖尿病临床惰性形成原因及对策研究

背景自2009年起,社区2型糖尿病(T2DM)健康管理作为国家基本公共卫生服务项目在全国得到推广实施,但由于临床惰性(即发现问题未能及时采取干预措施)的影响,造成患者血糖长期控制效果不佳,因此如何克服临床惰性以提高血糖控制率是优化糖尿病健康管理所面临的一项重要而紧迫的任务。目的识别社区T2DM健康管理过程中临床惰性发生的关键失效模式,系统分析关键失效模式的发生原因,并提出相应的干预对策措施。方法立足社区实情,以医疗失效模式与效应分析(HFMEA)框架为指导,通过实地调研、访谈及文献归纳分析法初步明确社区T2DM健康管理流程、临床惰性发生的原因及干预措施。文献检索时间为2020-01-01—2023-06-30。在此基础上,应用德尔菲法,选择16名专家于2022-01-10—02-25期间进行两轮专家咨询,最终确定社区T2DM健康管理过程中临床惰性发生的关键失效模式、发生原因和干预措施。结果第一轮和第二轮专家权威系数分别为0.791和0.729。最终通过计算风险优先指数(RPN)量化确定了社区T2DM健康管理过程中临床惰性发生的10个关键失效模式,按RPN从大到小,依次为未(及时)胰岛素治疗、未(及时)戒酒、未(及时)常规转诊、未(及时)戒烟、未(及时)紧急转诊、未(及时)三联治疗、未(及时)控制体质量、未(及时)调整膳食结构、未(及时)二联治疗和未(及时)发现低血糖,并从患者、医生及卫生系统层面阐明了关键失效模式形成的根本原因,制定了针对性的干预措施。结论制定的临床惰性干预措施具有较高的科学性和权威性,为优化社区T2DM健康管理模式奠定了基础。

多维高斯贝叶斯算法造纸机械设备故障自动检测优化设计

信息技术进步发展背景下,各行业已经开始使用机械化设备进行生产,进而提升生产质量。虽然造纸设备能大幅度的提升整体生产的效率,但由于其整体的复杂性,在生产运动过程中会出现故障。基于此,设计多维高斯贝叶斯算法造纸机械设备故障信息诊断系统;利用完整的框架结构设计客户机/服务器模式,联合服务器与信息查询模块,实现造纸机械设备故障信息诊断系统的体系结构搭建;在此基础上,计算故障信息的松弛度数值,通过判定迭代门限的方式,实现对多维系数信号的处理,完成多为高斯贝叶斯算法造纸机械设备故障自动检测功能。最后结合造纸机械设备故障情况提出同步维修、分步维修、易维修设计等方法,为造纸机械设备的正常平稳运行提供了技术保障。

胰岛素抵抗代谢评分与慢性心力衰竭患者不良预后的相关性研究

背景胰岛素抵抗(IR)与心血管疾病的发生、发展关系密切,目前多项研究已经证实了IR在心力衰竭(HF)患者中非常普遍,并与不良心血管结局有关,而反映IR的指标——胰岛素抵抗代谢评分(Mets-IR)与慢性心力衰竭(CHF)患者不良预后之间的关联目前尚不明确。目的分析Mets-IR与CHF患者不良预后之间的相关性。方法本研究为回顾性研究,选取2020年1月—2021年1月在郑州大学第二附属医院心血管内科确诊为CHF的患者313例为研究对象。根据是否发生全因死亡将患者分为两组:全因死亡组(61例)和对照组(252例)。将Mets-IR作为分类变量进行分析,以中位数将Mets-IR分为两类:低水平Mets-IR(Mets-IR<37.28)和高水平Mets-IR(Mets-IR≥37.28)。收集患者基线资料,其中包括Mets-IR及其年龄、血清生物标志物和超声心动图指标,随访截至2022-12-31。通过本院电子病历系统或电话随访收集患者预后情况,主要终点事件为全因死亡,次要终点事件为因HF再入院。不同水平Mets-IR患者全因死亡及因HF再入院的生存曲线采用Kaplan-Meier图和Log-rank检验进行分析。应用Cox比例风险回归模型分析Mets-IR与全因死亡及因HF再入院风险的相关性。构建受试者工作特征(ROC)曲线,分析Mets-IR对CHF患者全因死亡及因HF再入院风险的预测价值。结果中位随访时间25.0(9.0,28.5)个月,313例CHF患者中出现全因死亡61例(19.5%)、因HF再入院121例(38.7%)。全因死亡组患者年龄、BMI、空腹血糖、Mets-IR、N末端B型钠尿肽前体、血尿酸、中性粒细胞计数、红细胞分布宽度、心房颤动、高血压、利尿剂、醛固酮受体拮抗剂、美国纽约心脏病学会分级高于对照组,三酰甘油、高密度脂蛋白胆固醇、低密度脂蛋白胆固醇、白蛋白、血红蛋白、血钠、左心室射血分数、血管紧张素转化酶抑制剂/血管紧张素受体拮抗剂/血管紧张素受体-脑啡肽酶抑制剂低于对照组(P<0.05)。Log-rank检验结果显示,高水平Mets-IR患者的全因死亡率及因HF再入院率均高于低水平Mets-IR患者(P<0.001)。调整多个混杂因素后的Cox比例风险回归分析结果显示,与低水平Mets-IR患者相比,高水平Mets-IR患者全因死亡风险(HR=2.90,95%CI=1.51~5.54,P=0.001)、因HF再入院风险(HR=1.55,95%CI=1.04~2.30,P=0.030)均升高。Mets-IR预测全因死亡风险、因HF再入院风险的ROC曲线下面积分别为0.68(95%CI=0.62~0.75)、0.62(95%CI=0.55~0.68)。结论Mets-IR水平升高可能会增加CHF患者的全因死亡及因HF再入院风险,可用于CHF患者的危险分层。

基于FMEA和RCA的适老化智能家电产品交互设计研究

目的为了进行智能家电产品的适老化升级,提升老年人的用户体验。方法提出基于失效模式与效应分析(FMEA)和根本原因分析(RCA)的适老化智能家电产品交互设计方法。首先,通过构建老年人使用智能家电的用户旅程图识别失效模式,利用FMEA对失效模式进行分析并评估风险优先指数;其次,根据风险优先指数绘制帕累托图确定重点失效模式,并运用石川图分析其发生的根本原因;再次,围绕根本原因对智能家电产品交互设计进行改良;最后,对改良后的设计进行测试并评估改良效果。结论选取智能洗衣机作为案例进行研究,结果表明所提出方法能够有效识别老年人使用智能家电时发生的失效模式,并对其发生的根本原因进行分析,可为适老化智能家电产品的设计优化提供方法参考,帮助老年人享受技术红利,跨越数字鸿沟。