Safety Reliability Analysis Considering Accidents Originating from Human Error on Preventive Design of Marine Man-Machine Systems

人为事故的系统可靠性分析是近年来研究的热点之一。本研究主要包括以下三个部分，在船舶人机系统功能设计中考虑人为失误事故的安全性和可靠性分析。第一部分提出了船舶系统功能设计中事故发生概率估计的分析方法。首先，采用故障树（FT） ^<1)>对设计功能系统的可靠性进行定性分析。其次，在功能系统中，人为错误的概率和设备故障的频率是通过使用忧虑度来确定的，忧虑度被定义为类似于基于工程师经验和聪明才智的感知尺度。最后，利用布尔逻辑进行改进项的选择，以降低功能系统的事故概率风险。在计算中，基于故障树分析和模糊理论，定量预测了自适应对策的效果。第二部分描述了一些事件的不可测性和事故对策的可测可靠性。采用事件树分析法（ETA）对船舶系统功能设计的可靠性进行评价。一般来说，ETA通过考虑导致事故的每个扬尘事件的发生概率来估计事故的发生概率。与人为错误有关的粉尘事件的准确估计通常很难找到，因为这些事件包括几个不可测量的因素，并且结果可能具有很大的误导性。在这一部分中，提出了一种考虑人为错误等粉尘事件可测性的可靠性分析方法。这种可测信度的估计过程是基于对所发生事件的确信程度，并采用信度度量或似度度量进行模糊积分评价。第三部分是海洋暴露作业空间中人体热应力的特点及对策研究。为了掌握人体热应激与热环境因素之间的关系，利用人体热平衡模型，建立了热应激计算公式，以期计算人体的蓄热量。该公式由温度、风速、代谢热和服装热阻组成，可定义为人体基础温度变化超过固定阈值时设定极限时间的临界工作时间。运用现有的判断方法，评价了几种补偿设备对工人在严重暴露环境下防护的必要性。少

The development of system reliability analysis of marine accidents originating from human error is regarded as being of major importance in recent years. This study, that consists of the following three parts, presents the safety and reliability analysis considering accidents originating from human error on the functional design of marine man-machine systems.The first part presents an analytical method for the estimation of the incidence probability of accidents during the function design of marine systems. Firstly, the qualitative analysis of the reliability of the functional system under design is carried out using the fault tree(FT) ^<1)>. Next the probability of human error and the frequency of device failure in the functional system are decided by using a degree of apprehensive, which is defined as similar to the sensible scale based on the experience and ingenuity of engineers. Lastly, the selection of improved items are executed by the calculation using Boolian logic to reduce t … More he risk of accident probability in the functional system. The effects of adapting countermeasures are predicted quantitatively in the calculation based on the fault tree analysis and the fuzzy theory.The second part describes un-measurability of some events and the measurable reliability of accident countermeasures. The event tree analysis(ETA) is used to evaluate reliability of the functional designs of marine systems. Generally, the ETA estimates the incidence probability of an accident by considering the incidence probability of every duster event leading to the accident. The exact estimation of duster event related to human errors is generally difficult to find, since those include several un-measurable factors, and the results could be highly misleading. In this part, a method of reliability analysis considering the measurability of some duster events like human error is proposed. This estimation process of measurable reliability is based on the firm degree of belief of the occurred event and an evaluation by a fuzzy integral using Belief measure or Plausibility measure.The third part is a characteristic study on thermal stress and countermeasures for human body in marine exposure working space. In order to grasp the relation between the heat stress of human body and the thermal environmental factors, a formula for heat stress is established with a view of calculating the quantity of heat storage using the heat balance model of human body. This formula that is consisted of temperature, wind velocity, metabolic heat and clothes heat resistance, can be defined to be the critical working hours to lay down the limit time when a variation of body foundation temperature exceeds the fixed threshold value. The necessity of several kinds of compensated equipment for the protection of workers against severe exposure environment is evaluated by use of present judgment method. Less