CMS-BN: A cognitive modeling and simulation environment for human performance assessment, part 2 — Application

Human operators play a critical role in the operation of complex engineered systems, in particular under abnormal conditions. It is important to assess human performance under conditions of interest and to improve upon the performance by taking effective measures. In this paper we present the application of a previously developed cognitive modeling and simulation environment to address these two problems. The developed environment simulates how a human operator dynamically interacts with the external system, with focus on the operator’s cognitive activities. Based on the Three Mile Island accident, specifically the stuck-open failure of the pilot operated relief valve, we demonstrate how the developed environment can be used for human reliability analysis and human performance improvement. For human reliability analysis, besides providing a single human error probability value the proposed environment allows us to examine in detail how an operator reached a decision or missed an action. For human performance improvement, the proposed environment provides an easy approach for investigating the effects of changes, for example, in operator training and system design, on human performance and therefore identifying the most effective changes to improve human performance.