【摘 要】 指出了目前用模糊评价法确定系统的安全等级所存在的问题和不足之处。分别运用模糊随机变量理论和模糊集理论而提出了安全等级模糊随机特征量和安全等级模糊特征量的概念及其计算方法。安全等级特征量及安全等级变量,均为安全等级取值论域上的模糊子集,而并非是一个确定的点。还给出了安全等级的绝对可能性和相对可能性的计算方法。实例表明,笔者所提出的安全等级特征量及可能性的计算方法是科学的、合理的。
【关键词】 安全等级 评价 模糊随机特征量 模糊特征量 可能性 characteristic quantity of safety grade and its calculation method
xu kaili chen baozhi
( school of resource and civil engineering, northeast university)
chen quan
(center for accident investigation and analysis, state economic and trade commission)
abstract using the method of fuzzy evaluation, existing problems and shortcomings are pointed out as the time of system safety grade being defined. by using fuzzy random variable theory and fuzzy set theory, the concept and its calculation method of fuzzy random characteristic quantity of safety grade are put forward. both characteristic quantity of safety grade and its variable are the value obtained from the fuzzy sub-set of safety grade on domain, and are not a definite point. calculation method of absolute and relative possibility is also given. system safety in future can be evaluated and forecasted in a definite condition by the calculation method of fuzzy random characteristic quantity of safety grade. examples demonstrate that calculation method of characteristic quantity of safety grade and the possibility pointed out in this paper are scientific and rational.
key words: safety grade evaluation fuzzy random characteristic quantity
fuzzy characteristic quantity possibility
1 系统安全等级的模糊性
在评价系统的安全水平或等级时,人们常用“极其安全”、“十分安全”、“十分危险”和“极其危险”等不确定性的语言表达方式。LOcalhOsT这是因为安全和危险是相对的,两者具有亦此亦彼的过渡性质,即具有模糊性。因此,要准确、客观地描述系统的安全等级却十分困难,只能尽可能地使评价结果符合客观实际。其原因是影响系统安全性的因素众多而复杂,且具有模糊性。例如,机械设备可靠性及安全管理水平的“高”与“低”,环境条件的“优”与“劣”,人、机配合的“好”与“差”,等等。在进行评价时,所获得的原始数据也具有模糊性。当然,也不能排除在某些系统中,影响其安全的因素具有确定性,
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