Revealing success factors of safe ship operations of experienced captains to assess functional requirements of Maritime Autonomous Surface Ships using FRAM

It is essential to reveal skills of experienced captains in order to define functional requirements of Maritime Autonomous surface ships(MASS).While textbooks,manuals,and laws define rules for captains and officers to follow,there are lots of other tacit knowledge,which are not written in documents,for safe ship operations.In this respect,it is essential to take into account complex dependencies among tasks/subtasks to build"an experienced captain's model".In order to accomplish this goal,we adopted a function-based modeling methodology which can support rich environmental factors for analyzing ship management operation.In this research,we conducted the following two steps to identify functional requirements of MASS,i.e.,1)modelling the skills of officers of the watch(OoW)from literature reviews,2)analyzing the actions of OoWs from the data acquired with gaze movements. Firstly,we performed modellings of OoWs'skills by utilizing FRAM.FRAM provides a way to describe how systems work in given working environment by using a characteristic functional representation of the systems as a diagram;each function of the systems is defined with six aspects,visually represented as a hexagon whose vertexes correspond to each of them,and eventually the systems are represented as a network of the six aspects.This representation provides complex dependencies among functions,and moreover,deeper insights about how the systems are successfully functioning.Secondly,we analyzed actions of OoWs observed in the simulator trial s,using data obtained from an eye-tracker,videos,and a wearable device to measure heart rate variability.Then we have examined relationships between the variety of the OoWs'actions and the heart rate variability.This study will contribute to define functional requirements of MASS for safety ship operations and assess the functions of MASS to develop.