Reliability Analysis Considering Items Related to Human Error on Functional Design Applications of Marine Safty Systems

随着混合国籍船员的技术能力下降，发生碰撞、搁浅或船舶火灾等海上事故的频率也有逐渐增加的趋势。近年来，人们对预防人为失误引起的海上事故的可靠性分析方法的发展越来越感兴趣，本文提出了一种在海上安全系统功能设计应用中估计事故发生概率的分析方法。这个概率估计过程分为三个阶段。首先利用故障树对设计中的功能系统进行可靠性定性分析。接下来，通过使用不安全程度来确定功能系统中人为错误的概率和设备故障的频率;该程度被定义为与基于工程师的经验和独创性的感觉尺度相似。最后，在使用布尔函数进行计算时，采用了改进的项目选择方法，降低了功能系统中的风险事故概率。基于故障树分析和模糊理论，对所采取的对策效果进行了定量预测。作为一个实际例子，在船舶火灾过程中，使用所提出的方法研究减少发生率的火灾蔓延。

With the deterioration of the technical ability of crew members of mixed nationalities, the frequency of incidence of marine accidents such as collisions, running agrounds or ship fires ; also tends to increase gradually. The development of a methodology for the reliability analysis of the means available for the prevention of marine accidents originating from human errors is becoming highly desirable in recent years.This study presents an analytical method for the estimation of the incidence probability of accidents during the functional design applications of marine safty systems. This process of probability estimations is divided into three stages. Firstly, the qualitative analysis of the reliability of the functional system under design is carried out using the fault tree. Next, the probability of human error and the frequency of device failure in the functional system are decided by using a degree of unsafeness ; which is defined as similar to the sense scale based on the experience and ingenuity of engineers. Lastly, the improved choice of items are used in the calculation using the Boolian function to reduce the risk of accident probability in the functional system. The effects of countermeasures adopted are predicted quantitatively in the calculation based on the fault tree analysis and the fuzzy theory. As a practical example, the conditions for reducing the incidence of fire spreads during a ship fire are investigated using the proposed method.