柔性版市场热销数字版材——美国FTA调查披露数字柔版呈增长趋势

北美的各印前贸易市场传来的反馈信息表明,数字革命时代已经来临。美国柔印技术协会(FTA)根据对其所属的印前贸易市场和被调查单位的调查结果预计,数字版材的市场份额将从目前的15.8%在未来4年内增长到53.2%。“当人们了解到第一代产品的优势以后,数字版材就为柔印创造了良好的发展机遇”,多年从事柔印生产的楞姆斯·赫哈尼克经理说:“就柔印所具有的效率和利益来说,数字版材可以与高水平的平印和凹印相媲美。”目前,这项调查表明每个供应商经营数字版材与普通版材的平均百分比为15.8%(数字版)∶84.2%(普通版),大部分供应商相信这个比率会…     

Selection of minimal tripping times for distance protection using fault trees with time dependencies

Correct coordination between protection relays is an essential requirement to maintain stability and integrity of electrical power systems. Time settings of protection relays have to be adapted to time characteristics of electrical power systems and time settings of other protections. In the paper, fault trees with time dependencies (FTTD) are used for selecting time delay settings of remote back-up distance protections. In FTTD, events and gates are characterized by time parameters, which are derived from time characteristics of protection devices and the inherent delays of protection equipment. Two case studies are presented. First, the coordination of protections for the simple transmission line composed of two identical sections is studied. Next, the transmission line that contains two sections of different lengths and transformer between them is analyzed. In both cases, formulae for time delays of protections are derived. According to calculations executed for the first case, our method gives time delays that often are significantly smaller than values suggested by generally recommended and accepted rules.     

基于三角模糊数的化工生产事故FTA模型

针对化工生产模糊系统,基于三角模糊数和事故树建立事故定量分析模型。运用该模型进行案例分析,确定储油罐体发生火灾爆炸事故的概率分布,得出基本事件的模糊重要度,明确该化工系统危险源分布的状态,指出导致事故发生的最危险路径,以上为企业管理人员制定安全措施提供重要的参考依据。     

基于故障树分析的航天发射场电力保障技术的研究

针对发射场某供电回路故障,应用故障树分析法建立故障树模型,并进行定性和定量分析。讨论了故障最小割集、各底事件的概率重要度和相对重要度,通过短路电流计算,验证了故障树模型及分析的正确性。该方法在电力保障及故障分析定位中发挥了较大作用。     

金属矿山供电系统安全性分析及事故预防对策

本文介绍了某金属矿山供电系统概况,对该矿供电系统常见危险因素进行分析,并采用事故树分析法对供电系统进行安全评价,最后指出电气事故的预防措施。     

SMV model-based safety analysis of software requirements

Fault tree analysis (FTA) is one of the most frequently applied safety analysis techniques when developing safety-critical industrial systems such as software-based emergency shutdown systems of nuclear power plants and has been used for safety analysis of software requirements in the nuclear industry. However, the conventional method for safety analysis of software requirements has several problems in terms of correctness and efficiency; the fault tree generated from natural language specifications may contain flaws or errors while the manual work of safety verification is very labor-intensive and time-consuming. In this paper, we propose a new approach to resolve problems of the conventional method; we generate a fault tree from a symbolic model verifier (SMV) model, not from natural language specifications, and verify safety properties automatically, not manually, by a model checker SMV. To demonstrate the feasibility of this approach, we applied it to shutdown system 2 (SDS2) of Wolsong nuclear power plant (NPP). In spite of subtle ambiguities present in the approach, the results of this case study demonstrate its overall feasibility and effectiveness.     

船载时间统一系统GPS跳秒问题研究与改进

介绍了船载时间统一系统的组成和GPS模块的工作原理。指出了现有时间统一系统存在的GPS跳秒问题。针对船载时间统一系统GPS跳秒问题,建立FTA故障树分析模型,分析故障底事件,定位了GPS跳秒问题的故障部位是GPS定时接收机,并深入分析GPS接收机关于闰秒的相关原理,进一步精确定位了GPS跳秒问题的原因是GPS接收机的闰秒修正软件算法存在缺陷。为了解决该问题,采用在GPS解码程序中增加GPS跳秒检测机制的方法,检测GPS芯片是否发生跳秒现象来避免产生器误同步,从而避免GPS跳秒问题导致的系统时间异常。通过搭建GPS模块程序验证平台和设计GPS验证测试软件进行测试,结果表明改进后的GPS解码程序在检测到GPS定时接收机跳秒后,能使GPS定时接收机复位,并设置GPS信息不可用,避免产生器误同步,从而有效解决了GPS跳秒问题。     

一种基于FTA技术的制造过程质量体系诊断与控制方法

提出了一种基于故障树分析(FTA)技术的制造过程质量体系诊断与控制方法,给出了质量体系缺陷树及其结构函数的建立与分析方法,采用定性分析与定时计算的方法确定了质量体系的关键因素。     

Risk analysis using fault-tree analysis (FTA) and analytic hierarchy process (AHP) applicable to shield TBM tunnels

In this paper, the potential risk of undesirable events occurring during tunneling with application of a shield tunnel boring machine (TBM) method is discussed along with the risk analysis which can systematically assess overall risk levels. Potential risks and typical scenarios pertaining to shield TBM tunnels have been investigated based on previous case histories and correspondence with experts. The relevant risks from undesirable events were categorized into four groups: cutter-related malfunction, machine blockage or hold-up, mucking problems that hinder transporting excavated materials, and segment defects. A fault-tree set was constructed by grouping risk factors (or causes) into geological, design and construction/management factors. Risk analysis was performed by adopting fault-tree analysis (FTA) and an analytic hierarchy process (AHP) with consideration of the probability and impact of the risks. In addition, the proposed method was reliably validated by comparison with field observation, and thus indicates its applicability to risk management for shield TBM tunneling.     

M-LVDS总线FPGA软件安全性测试

随着FPGA(现场可编程门阵列)在航空航天、核能、轨道交通等领域中的广泛应用,由FPGA软件设计引起的安全问题日益突出。通过借鉴软件安全性分析方法,结合FTA、FMEA两种安全性分析技术,将这两种分析方法综合应用,对M-LVDS总线FPGA软件进行了安全性分析。采用仿真故障注入方式设计测试用例,对易引发系统高危失效的事件进行充分的安全性分析与测试,有效提高了M-LVDS总线FPGA软件的测试质量,同时为FPGA软件设计中常见的典型接口类应用安全性分析与测试提供了有益的探索和参考。