Safety Versus Reliability: Different or Equal!?

摘要

In this paper, we want to highlight and discuss the relationship between "reliability" and "safety". Although everyone involved in any of the two disciplines can immediately give definitions of the terms and explain their differences, we doubt that all professionals come up with the same conclusion. Quite in contrast, there would probably be many different opinions. The last System Safet / Conference included two presentations by two renowned experts in their field who had essentially opposit opinions. One expert argued that safety and reliability are completely unrelated, while the other expert arg led that safety depends on reliability. We want to discuss the reasons for these controversies to better understand the differences and similarities between the two concepts, and therefore to be able to choose the most effective methods to achieve high reliability and a high safety integrity. We will then show the application of reliability and safety techniques for a voice communication system in air traffic control and discuss if- in this special case - improving one property has a influence on the other property. We will show that the meaning of safety and reliability strongly depends on the domain (or the system) where the terms are used.