利用遗传算法进行软件可靠性增长模型参数估计

为解决利用传统数值方法估计软件可靠性增长模型参数值时存在的问题 ,笔者讨论了利用遗传算法进行求解的相关策略 ;提出了一种新的编码方式及变异算子 ;通过涉及多个模型的实验 ;采用实际数据 ,对所提出算法的效果与传统数值方法进行了对比。实验与对比分析结果显示 :该算法针对这些模型表现出了良好的普适性。     

提高冷拔内模使用可靠性的研究

用安全学科的观点 ,对冷拔内模进行宏观痕迹分析和磨损失效模式的确定 ,并结合摩擦学精典的磨损理论 ,对冷拔内模进行微观磨损机理分析 ,从而为提高冷拔内模使用可靠性提供了理论依据和有效措施。     

生态足迹模型在村庄层面应用的探索

以广西铜匠村的生态足迹模型为例探讨了生态足迹法在村庄层面应用的适用性。结论表明,生态足迹模型在衡量村庄生态状况时有着更为可靠的准确性,但也存在4种因素限制其精确性,数据获取较难、外出务工者较多、生态效益较大以及土地"兼职"较广。针对外出务工者的影响,提出了其时间折算法,对于其他缺陷则阐明了在模型完善方面的研究现状。     

Using data mining technology to explore causes of inaccurate reliability data and suggestions for maintenance management

Reliability data reflects equipment safety and provides a reference for setting inspection period, thereby serving as crucial information for the implementation of equipment integrity management policies. The calculation foundation of reliability data is maintenance records of adequate data quality. However, maintenance records of doubtful quality are common. Despite excluding poor quality recodes and using only the remaining maintenance recodes to calculate the reliability data, the calculated results generally lack a sufficient degree of confidence. This study applied data mining technology, including quality metrics, the association rule, and clustering, to explore the cause of low-quality maintenance data. The results revealed that the low data quality of maintenance records was due to ineffective maintenance policies, the low integrity of key system columns, nonadherence to the policy, and misunderstanding of column definitions. The proposed method successfully identified the causes of low-quality maintenance records. By incorporating the method into the function module of a CMMS, operators can equip the system with self-diagnosis, self-supervision, and continuous optimization functions.     

空调器印剧电路板(PCB)无铅焊点寿命评估研究

由于无铅焊料的应用,无铅焊点的可靠性问题得到了关注.本文针对无铅焊点的空调器印刷电路板(PCB),结合实际使用条件,采用加速寿命的方式,测试了焊点的寿命.并针对温度循环条件下的焊点,使用有限元模拟技术计算测定了其寿命,并与实验的结果进行了比较,取得了较吻合的结果.     

可靠性分析在矿柱回采研究中的应用

通过对某铜矿水平矿柱回采中的结构稳定性问题的研究,探讨了有限元计算结合结构可靠性分析的研究方法。研究表明,这对矿山工程的可靠性分析提供了新的思路和方法。     

影响重量法测定工业废水石油类准确性的几个因素

就影响重量法测定工业废水中石油类准确性的几个因素进行了讨论。     

First-trimester genetic diagnosis in multiple pregnancy: Principles and potential pitfalls

Both the principles of first-trimester genetic diagnosis in multiple pregnancy and the special considerations required to avoid potential diagnostic pitfalls are presented. The experience consisted of 65 cases of twins and one case of quadruplets. Dichorionic twins were recognized by sonography in 54 cases. Transabdominal aspiration was generally preferred to trans-cervical for obtaining chorionic tissue, although in two cases both approaches were used. Diagnostic error following erroneous sampling was reported in 3 out of 54 sets of dichorionic twins (5.5 per cent). When like-sex dichorionic twins cannot be differentiated by cytogenetic or DNA polymorphism studies, amniocentesis should be recommended to confirm the reliability of the result on chorionic tissue.     

废水处理设施设计参数的探讨

从废水治理设施设计标准方面对水处理工艺出水不达标的原因进行了分析，结果表明，在考虑废水治理设施可靠性的条件下，设计参数取值低于国家排放标准才能满足水处理的要求。     

人因可靠性分析方法

回顾了人因可靠性分析 (HRA)的发展历史 ;汇总了近几十年来的各种人因可靠性分析方法 ;详细介绍了人的失误率预测技术 (THERP)、人的认知可靠性模型 (HCR)、成功似然指数法 (SL IM)的背景、使用步骤、特性等 ;分析了 THERP+ HCR的优势 ,并给出了一个应用实例。最后 ,指出了目前 HRA方法的不足并预测了 HRA的发展趋势