Investigation on the Factors of VTS Operators' Mental Workload: Case of Japanese Operators

摘要

The level of VTS Operators' (VTS-Os') Mental Workload (MWL) was clarified in the previous experimental studies by utilising physiological and subjective approaches.The objective of this paper is to determine the factors to cause and increase VTS-Os' MWL.For this purpose,the questionnaire was prepared and submitted to the Japanese VTS operators who have been employed at different VTS areas;such as Akashi MARTIS,Kurushima MARTIS,Bisan Seto MARTIS and Kanmon MARTIS.The questionnaire consisted of multiple aspects of operators' mental workload such as ergonomics,occupational stress,physical and social conditions and environmental aspects,etc.operators evaluated all variables related to their tasks based on affecting to increase their mental workload by using a five-point Likert scale ranging from "Never" through to "Always".The higher score of the questionnaire item,the more effect on operators' mental workload.Then,Exploratory Factor Analysis was performed by using SPSS v.13.0 to obtain significant mental workload factors.The reliability of factor model was also tested by Cronbach's Alpha and it was determined a powerful internal consistency.In the further analyses,VTS-Os' MWL factors were tested whether they had similar effects or not,and the root of these differences was investigated.Moreover,the relationship between MWL factors and profile variables (such as age,marital situation,sea experience,VTS experience,educational level and competency) was investigated by using proper statistics techniques (e.g.one-way ANOVA and post hoc tests).The results revealed that the proposed factor model could explain Japanese VTS Operators' MWL by 82% and some differences among the operators were determined as significantly.