System Safety, Risk Management, and Human Performance Improvement

System safety concept is the most important philosophy for improving the safety of the huge complex system. Every engineer knows well and always considers about “The local optimization would make the entire worst of the system”, and therefore understands importance of the system safety concept that well balanced design and operation are required. At present, the existing huge complex systems have been reduced in hardware risk through hardware countermeasures and quality assurance activities based on safety logic, so the remaining risk can be said to be events involving human factors. For this reason, risk reduction activities can be described as human performance improvement activities. Risk informed decision-making can be said a decision-making framework that improves human performance, based on the probabilistic risk assessment results. Furthermore, continuing this activity will eventually lead to the maintenance and improvement of the safety culture. In other words, what we want to emphasize here is that “system safety”, “risk reduction activities”, “human performance improvement activities”, “risk informed decision-making”, and “maintenance and improvement of safety culture” have similar purposes and contents.