Before revision:  The experimental results indicate that some features, such as task execution time and user head movements, are good indexes for skill level and provide valuable information that can be applied to obtain an effective task model. Operators with varying knowledge and operating habits demonstrate different operational features, which can contribute to the design of user-specific guidance .
After revision:  The experimental results indicate that some features, such as task execution time and user head movements, are good indexes for skill level evaluation, and provide useful information for integrating various records corresponding to different skill levels and behavioral characteristics. Integrating operation records with operating habits allowed developing a rich inclusive task model that could be used to flexibly adapt to various user-specific guidance .