An Evaluation of Task Network Modeling for Use in Simulating Situation Awareness

Abstract

To achieve its mission of regulating the commercial nuclear power industry, the U.S. Nuclear Regulatory Commission (NRC) periodically commissions research studies to investigate potential safety issues. These include operational studies involving operator and crew performance. A main objective of these research projects is to provide information and knowledge that can be used in the development of regulation, regulatory guidance, and improved methods for collecting and analyzing personnel performance data to assist in regulatory inspections, investigations, and evaluations. The Halden Man-Machine Laboratory (HAMMLAB) in Halden, Norway recently conducted a study using professional nuclear power plant operators to investigate the effect of different alarm systems and display types on operator performance. Dependent variables in the Halden Alarm study included a mix of plant performance measures, operator task performance measures, operator cognitive processes, and subjective evaluations. Operator cognitive process measures included measures of Situation Awareness (SA) using an adaptation of the Situation Awareness Global Assessment Technique (SAGAT). Through the NRC, Micro Analysis and Design was allowed access to the work being performed at Halden in order to evaluate the use of Task Network Modeling (TNM) to simulate human behavior in a nuclear power plant. The alarm system, a turbine trip scenario and data from Halden were used as the basis for the model developed in this project. For part of this project, we also developed a model to simulate SA that was representative of how it was measured in the Halden Alarm study. This model was then integrated into our model that represented a disturbance scenario at a nuclear power plant. Data generated by the task network simulation was then compared to data collected from the nuclear power plant simulator at the HAMMLAB.Statistical tests showed no significant differences between the SA scores of actual operators and those SA scores predicted by the model. Thus, results indicate that a simple representation of SA within TNM can be used to accurately predict situation awareness given this measuring technique.Implications of this finding and recommendations for improving the model are discussed.

Trends in HFE Methods and Tools and Their Applicability to Safety Reviews

“…Other applications have included the prediction of operator response to disturbance scenarios (Yow et al, 2005) and the prediction of situation awareness (Walters & Yow, 2000).…”

Using fuzzy cognitive mapping techniques to model situation awareness for army infantry platoon leaders

“…First, cognitive architectures, such as ACT-R (Anderson and Lebiere 1998;Anderson et al 2004;Anderson 2007), Soar (Newell 1990), COGNET (Zachary and Le Mentec 1999), R-CAST (Fan et al 2005), andCoJACK (Evertsz et al 2009) use computational processes to describe the structural properties of cognitive behaviors, including the formation of operator SA. Second, cognitive models, which are generally designed to describe a single cognitive phenomenon (and in certain cases, are built from a cognitive architecture) include the MIDAS SA model (Shively et al 1997), SACRI-based model on SAGAT (Walters and Yow 2000), TacAir-Soar agents (Jones et al 1999), dTank models (Ritter et al 2007), and MicroSaint task network models (Archer et al 2000). Lastly, intelligent agent-based systems, such as the Beliefs, Desires, and Intentions (BDI; Bratman 1987) framework, generally employ intentions, agent's beliefs, inferences, behaviors, and rules to describe SA.…”

Applying Human-performance Models to Designing and Evaluating Nuclear Power Plants: Review Guidance and Technical Basis

“…In an earlier study with the same simulator data, Walters and Yow (2000) had developed a model to predict situation awareness. During pauses in the simulation, the operators were asked to recall whether selected process parameters were increasing, decreasing, or unchanging.…”