Analysis of Incomplete Data of Accelerated Life Testing with Competing Failure Modes

Data obtained from accelerated life testing （ALT） when there are two or more failure modes, which is commonly referred to as competing failure modes, are often incomplete. The incompleteness is mainly due to censoring, as well as masking which might be the case that the failure time is observed, but its corresponding failure mode is not identified. Because the identification of the failure mode may be expensive, or very difficult to investigate due to lack of appropriate diagnostics. A method is proposed for analyzing incomplete data of constant stress ALT with competing failure modes. It is assumed that failure modes have s-independent latent lifetimes and the log lifetime of each failure mode can be written as a linear function of stress. The parameters of the model are estimated by using the expectation maximum （EM） algorithm with incomplete data. Simulation studies are performed to check＇model validity and investigate the properties of estimates. For further validation, the method is also illustrated by an example, which shows the process of analyze incomplete data from ALT of some insulation system. Because of considering the incompleteness of data in modeling and making use of the EM algorithm in estimating, the method becomes more flexible in ALT analysis.

Landscape Design Mode Based on the Integration of Ecology, Production and Life

Taking landscape design of Suburban Park in Yulin City for example, this paper applied the design thoughts of integrating multiple planning, defining concepts and objectives, specified the design strategies of restoring ecology, improving life and promoting production, and disclosed the landscape design mode based on the integration of ecology, production and life in which ecological landscapes, productive landscapes and living landscapes promote and coexist harmoniously with each other.

基于Second Life的情境体验式教学模式设计

从情境认知理论和沉浸理论出发,在深入剖析Second Life构成要素的基础上,利用Second Life的情境性和交互性的优势,设计Second Life环境中的情境体验式教学模式。

青少年抑郁障碍患者防御方式和生活事件对心理健康的影响

目的 了解青少年抑郁障碍患者的防御方式和生活事件与心理健康的关系,为青少年抑郁障碍的防治提供依据。方法 选取我院门诊及住院的青少年抑郁障碍患者作为研究组共161例,健康体检者及在校学生作为对照组共180例,采用心理健康症状自评量表(SCL-90)、防御方式问卷(DSQ)及青少年生活事件量表(ASLEC)进行评估。两组所得量表数据使用SPSS 22.0进行统计分析。结果 研究组的ASLEC与SCL-90总分均高于对照组(P<0.05);青少年抑郁障碍患者DSQ中不成熟型防御机制评分与SCL-90和ASLEC评分呈显著正相关(P<0.05);成熟型防御机制与SCL-90和ASLEC评分呈负相关(P<0.05);中间型防御机制与SCL-90和ASLEC评分无明显相关性(P>0.05)。结论 青少年抑郁障碍患者的不良生活事件发生频率高于同龄健康人群,其心理健康水平明显低于同龄健康人群。不成熟防御机制是影响心理健康情况的高危因素,而成熟防御机制是心理健康情况的良好保护因素,中间型防御机制和掩饰因子对心理健康情况无直接影响关系。

基于微信平台的延续性护理模式对尿路结石患者术后生活质量的影响

目的探讨基于微信平台的延续性护理模式对尿路结石患者术后生活质量的影响。方法选取2022年1月—2023年1月于曹县人民医院行手术治疗的尿路结石患者60例,依据随机数字表法分为两组,对照组(n=30)采用常规护理模式干预,观察组(n=30)采用基于微信平台的延续性护理模式干预。比较两组干预前后自护能力、生活质量评分以及并发症发生情况。结果干预后,观察组自我护理能力量表(ESCA)、健康调查量表36(SF-36)评分均高于对照组(P<0.05);观察组并发症总发生率低于对照组(P<0.05)。结论基于微信平台的延续性护理模式可提高尿路结石患者的术后自护能力,改善其生活质量,且能够降低并发症总发生率,值得应用。

Second Life在中小学信息技术教学中的应用初探

对中小学信息技术课程教学存在的问题进行深入分析,力求挖掘源于学习主体、课程自身特点、教学方式等方面的制约因素,结合Second Life自身良好的教育特征,探讨Second Life在解决中小学信息技术课程教学中存在的问题的可能性,以促进中小学信息技术课程教学的最优化。

康复前移模式护理对直肠癌造口手术患者的影响

目的:探究康复前移模式护理对直肠癌造口手术患者的影响。方法:选取2022年6月—2024年3月厦门大学附属第一医院收治的80例直肠癌造口手术患者。根据随机数表法随机将其分为对照组和观察组,各40例。对照组实施常规护理,观察组在对照组基础上实施康复前移模式护理。比较两组入院时、术后1 d心理状况,病耻感,入院时、出院3个月后生活质量和自护水平,造口相关并发症。结果:术后1 d,两组焦虑自评表(SAS)、抑郁自评表(SDS)评分均降低,观察组SAS评分、SDS评分均低于对照组,差异有统计学意义(P<0.05)。出院时,观察组社会排斥、社会隔离、经济歧视和内在羞耻感评分均低于对照组,差异有统计学意义(P<0.05)。出院3个月后,两组生活质量综合问卷(GQOL-74)、自我护理能力量表(ESCA)评分均升高,观察组GQOL-74评分、ESCA评分均高于对照组,差异有统计学意义(P<0.05)。观察组造口相关并发症发生率为2.50%,低于对照组的17.50%,差异有统计学意义(P<0.05)。结论:康复前移模式护理在减轻直肠癌造口手术患者不良心理、病耻感方面有显著的优势,可提升患者的生活质量、自护能力,对减少造口并发症发生有积极的意义。

Impact of personality and coping mechanisms on health-related quality of life in liver transplantation recipients

With the great development of liver transplantation in China, long survival and quality of life after liver transplantation have been matters of growing interest. This study was designed to investigate the impact of personality and coping skills on the quality of life after liver transplantation. METHODS:Fifty-five outpatients who had been followed up after liver transplantation at our center were assessed by general quality of life inventory (GQOLI-74 ), a medical coping modes questionnaire (MCMQ), an eysenck personality questionnaire (EPQ), and a general condition questionnaire (GCQ). RESULTS: The score for material well-being was the lowest (63.22±12.67) and for psychological well-being the highest (73.43±12.60) in 4 dimensions of the GQOLI in post transplantation patients. Their main coping method was confrontation (21.40±3.70). The main characteristics of their personality were extraversation (E score 12.96±4.13) and neuroticism (N score 8.20±4.90) . The total score of the GQOLI was positively correlated with confrontation and E score, and it was negatively correlated with acceptance and N score. The physical well-being positively associated with the E score. The psychological well-being was positively correlated with confrontation and L score, and was negatively correlated with acceptance, P and N score. Social well-being was positively correlated with confrontation and E score, and was negatively correlated with acceptance and N score. Material well-being was not correlated with coping methods and personality. CONCLUSION:The quality of life in post liver transplantation patients is associated with their psychological characteristics.

医学生-病友参与式健康管理对合并2型糖尿病的脑梗死患者生活质量的影响

目的探讨医学生-病友参与式健康管理对合并2型糖尿病的脑梗死患者生活质量的影响。方法选取首次发作、美国国立卫生研究院卒中量表(National Institute of Health stroke scale,NIHSS)评分为1~4分且合并2型糖尿病的脑梗死患者随机分为对照组(49例)和研究组(47例),对照组行常规健康管理,研究组在此基础上,结合Learns模式,引入医学生和病友参与。对比管理前后2组患者血糖水平、生活质量、Barthel指数(Barthel Index,BI)等变化。采用Spearman相关性分析探讨SF-36评分与BI评分的相关性。结果干预前,2组FBG、2 h PG、HbA1c、BI评分比较差异无统计学意义(P>0.05);干预后,研究组FBG、2 h PG、HbA1c、BI评分均优于对照组(P<0.05)。研究组SF-36评分的8个维度评分均优于对照组(P<0.05)。Spearman相关性分析结果显示:干预后研究组精力、社会活动、情感职能与BI正相关(r分别为0.469、0.758、0.453,P<0.01)。结论医学生-病友参与式健康管理能够改善合并2型糖尿病的脑梗死患者的血糖水平、改善生活质量、日常生活活动能力;关注患者的精力、社会活动、情感职能有助于提高其生活质量。

Casing life prediction using Borda and support vector machine methods

Eight casing failure modes and 32 risk factors in oil and gas wells are given in this paper. According to the quantitative analysis of the influence degree and occurrence probability of risk factors, the Borda counts for failure modes are obtained with the Borda method. The risk indexes of failure modes are derived from the Borda matrix. Based on the support vector machine （SVM）, a casing life prediction model is established. In the prediction model, eight risk indexes are defined as input vectors and casing life is defined as the output vector. The ideal model parameters are determined with the training set from 19 wells with casing failure. The casing life prediction software is developed with the SVM model as a predictor. The residual life of 60 wells with casing failure is predicted with the software, and then compared with the actual casing life. The comparison results show that the casing life prediction software with the SVM model has high accuracy.

The Toxicity, Persistence and Mode of Actions of Selected Botanical Pesticides in Africa against Insect Pests in Common Beans, P. vulgaris: A Review

Common beans are affected by many insect pests such as bean leaf beetle, aphids, legume pod borer and bean beetles. Traditional and cultural practices such as site selection, crop rotation, intercropping and seed selection, sowing date are used to reduce the infestation of insect pests of common beans in the field and in storage rooms. Natural enemies such as predators, parasitoids and pathogens can control the insect pests. Synthetic pesticides such as cypermethion, carbaryl, and lambda-cyhalothrin have reported to be effective, but are toxic to people, destroy natural enemies and contaminate the environment. Botanical pesticides are the promising alternatives. This review paper explains toxicity, persistence and mode of actions of active ingredients of botanical pesticides. Rotenone from T. vogelii has the oral lethal dose (LD50) of 132 - 1500 mg/kg to mammals. It delays the electron transport chain in mitochondria of the insects and limits the cellular energy production. Azadirachtin is antifeedant and growth disruptor of insects. It has low toxicity to mammals. The oral LD50 in mammals is greater than 3540 mg/kg. Azadirachtin displays strong effects on chemoreceptors of the insects. Pyrethrins are axonic poisons and have repellent effects to insects. It is less toxic to mammals with the LD50 of about 1500 mg/Kg. It attacks the nervous systems of insects. Sesquiterpene lactones from T. diversifolia, Pentacyclic triterpenoids from Lantana camara, Vernodalin, Vernodalol and Epivernodalol from V. amygdalina have repellent and feeding deterrents chemicals which discourage the insects from feeding the crop. Most active ingredients of botanical pesticides have short life span in the environment.

Residual Fatigue Life Prediction of Ball Bearings Based on Paris Law and RMS

Paris law can reflect the failure mechanism of materials and is usually used to be a method to predict fatigue life or residual fatigue life.But the variable which can represent the health of machine is hardly measured on line.To a degree,the difficulty of on-line application restricts the scope of application of Paris law.The relationship between characteristic values of vibration signals and the variable in the Paris equation which can describe the health of machine is investigated by taking ball bearings as investigative objects.Based on 6205 deep groove ball bearings as a living example,historical lives and vibration signals are analyzed.The feasibility of describing that variable in the Paris equation by the characteristic value of vibration signals is inspected.After that vibration signals decomposed by empirical mode decomposition（EMD）,root mean square（RMS） of intrinsic mode function（IMF） involving fault characteristic frequency has a consistent trend with the diameter of flaws.Based on the trend,two improved Paris models are proposed and the scope of application of them is inspected.These two Paris Models are validated by fatigue residual life data from tests of rolling element bearings and vibration signals monitored in the process of operation of rolling element bearings.It shows that the first improved Paris Model is simple and plain and it can be easily applied in actual conditions.The trend of the fatigue residual life predicted by the second improved Paris model is close to the actual conditions and the result of the prediction is slightly greater than the truth.In conclusion,after the appearance of detectable faults,these improved models based on RMS can predict residual fatigue life on line and a new approach to predict residual fatigue life of ball bearings on line without disturbing the machine running is provided.

基于模态分解和神经网络的锂电池RUL预测

为了准确地预测锂电池剩余使用寿命(RUL)的整体退化趋势和局部容量恢复现象,此处提出了一种将改进的自适应噪声完备集合经验模态分解(ICEEMDAN)与卷积神经网络(CNN)和双向长短期记忆(BiLSTM)神经网络相融合的模型。首先选取电池容量数据作为输入量,利用ICEEMDAN将本征模态分量和残余模态分量进行分离,然后根据两种分量的特征分别选取BiLSTM神经网络和CNN进行预测,最后将两者进行叠加得到预测结果。采用某机构数据集进行RUL预测实验,与单一模型进行对比实验。实验结果表明,基于模态分解的混合神经网络预测模型具有更高的稳定性和精确度;采用NASAPCoE数据集进行泛化性实验,验证了该模型在不同型号电池的RUL预测中都具有良好的准确性,可以被广泛使用。

传统村落居民非遗日常生活实践中情感交换模式演变过程及机制——以皇都村侗族大歌为例

随着中国乡村振兴战略的推进,传统村落居民的情感受到越来越多学者的关注,而传统村落非物质文化遗产是其居民情感的重要载体,传统村落城镇化、旅游化的过程中,其非物质文化遗产承载的情感及其交换模式也在不断的演变。文章基于日常生活实践理论,以皇都村侗族大歌为案例,采用半结构化访谈和参与式观察等质性研究方法,通过构建“日常生活实践-情感交换”的分析框架,探讨传统村落居民在非遗日常生活实践中情感交换模式的演变过程及动力机制。研究发现:1)根据侗族大歌实践中的权力博弈演变,可将皇都村日常生活实践分为4个阶段:原始平衡阶段、被动妥协阶段、主动抵制阶段、融合再生阶段;2)皇都村居民非遗日常生活实践中情感交换模式的演变经过从互惠型依次向一般型、协商型和生产型转变的过程;3)传统村落居民非遗日常实践中情感交换模式演变具有系统性,外缘系统的演变推动内核系统调适,推动力、牵引力和支撑力构成其演变的动力机制。情感交换模式的演变过程展现居民在面对非遗资本化时的抵制策略与情感调适过程,对非遗保护实践中情感治理具有借鉴意义。

基于放电电压平台研究的蓄电池寿命状态评估

为解决传统动车组镍镉蓄电池的返修方法导致部分蓄电池在触发返修条件前已性能劣化,同时大量已达返修标准的蓄电池性能并未过度衰退的问题,设计单体镍镉蓄电池全寿命加速老化实验并获取相关实验数据。首先,采用集成经验模态方法建立单体电池全寿命健康状态类别划分模型,然后运用离散小波变换消除放电电压平台数据的奇异值,进而利用极限学习机算法预测蓄电池寿命状态,最终实现对蓄电池全生命周期寿命的准确预测与健康状态评估功能。实验结果表明:相较于传统的蓄电池寿命阈值分类方法,运用集成经验模态建立的健康状态类别划分模型能有效避免蓄电池寿命末端出现误警情况。作为融合算法模型输入的放电电压平台数据易获取,基于离散小波变换的数据预处理方法可提升算法准确率近3%,最终可达到96%~98%。此外,相对于传统的神经网络模型,融合算法模型不涉及迭代,因而能兼顾算法的预测精度与计算效能。蓄电池识别健康状态的F1值为0.976 3,识别老化阶段的F1值为0.950 9,识别故障阶段的F1值为0.939 394。相较于传统的依据动车组运营里程和使用年限进而决定蓄电池是否返修的方法,融合算法模型提供了显著的评判标准,能判别蓄电池是否应该返修,并有效地识别蓄电池的健康状态,降低了动车组的运营成本,保障动车组运营安全,为电池寿命评判和检修策略的优化提供参考。

基于有限元分析的连续油管寿命研究及预测模型

目前针对连续油管的寿命预测研究较少,但在实际的生产中连续油管的突然失效会造成极大安全隐患,急需解决方案。针对此问题,本文使用有限元仿真方法,针对三种规格的CT80连续油管在不同工况下进行有限元分析,得到了连续油管的受力、形变和疲劳寿命。用疲劳试验对有限元分析进行验证,证明了有限元分析的疲劳寿命的准确性。将连续油管的直径、壁厚、内压、弯曲半径参数转化为外壁应变和环向应力,通过数据拟合建立了关于外壁应变、环向应力和疲劳寿命之间的全经验公式,得到连续油管疲劳寿命预测模型。并用试验得出的结果与疲劳寿命预测模型进行比较,误差较小,可用于CT80连续油管的疲劳寿命预测,最后通过疲劳试验得到了连续油管在二级加载下的疲劳寿命模型,该模型可预测油管在第二级载荷下的剩余疲劳寿命。

粤北地区社会心理因素对妊娠期妇女分娩方式选择及生存质量的影响

目的探究粤北地区社会心理因素对妊娠期妇女分娩方式选择及生存质量的影响。方法选取2022年1月—2023年5月在粤北人民医院住院的1000例单胎头位产妇为研究对象,根据选择的分娩方式将其分为镇痛阴道分娩组(412例)、普通阴道分娩组(286例)、剖宫产组(302例)。对比三组的社会-心理学特征,包括焦虑自评表(SAS)、抑郁自评量表(SDS)、艾森克问卷调查表(EPQ-RSC)、日常生活活动能力评定表(ADL)、生存质量评定量表(WHOQOL-BREF)的评分;对比三组的VAS评分以判定疼痛效应;对比三组的产程时间、产后2h内出血量以及住院天数。结果镇痛阴道分娩组的SAS、SDS与EPQ-ESC评分最低,剖宫产组的SAS、SDS与EPQ-ESC评分最高,组间差异有统计学意义(P<0.05);镇痛阴道分娩组的WHOQOL-BREF评分明显高于普通阴道分娩组与剖宫产组,差异有统计学意义(P<0.05);普通阴道分娩组与剖宫产组的WHOQOL-BREF评分差异无统计学意义(P>0.05);三组的ADL评分差异无统计学意义(P>0.05);镇痛阴道分娩组与普通阴道分娩组的宫缩间歇期与产后的VAS评分差异无统计学意义(P>0.05);镇痛阴道分娩组在宫口开3cm、宫口开7~8cm以及宫口开全时期的VAS评分均明显低于普通阴道分娩组,差异有统计学意义(P<0.05);镇痛阴道分娩组与普通阴道分娩组的住院时间差异无统计学意义(P>0.05);镇痛阴道分娩组的产程时间与产后2h出血量均明显小于普通阴道分娩组,差异有统计学意义(P<0.05)。结论粤北地区的社会心理因素对妊娠期妇女的分娩方式选择和生存质量有显著影响,没有精神心理因素(如焦虑抑郁)影响的更愿意选择镇痛阴道分娩;而受精神心理因素(如焦虑抑郁)影响较大的,易选用剖宫产,且镇痛阴道分娩孕妇的生存质量明显高于常规阴道分娩与剖宫产孕妇。

理解人类文明新形态的生态向度

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