The industrial societies face difficulty applying traditional work-related musculoskeletal disorder (WMSD) risk assessment methods in practical applications due to in-situ task dynamics, complex data processing, and the need of ergonomics professionals. This study aims to develop and validate a wearable inertial sensors-based automated system for assessing WMSD risks in the workspace conveniently, in order to enhance workspace safety and improve workers’ health. Both postural ergonomic analysis (RULA/REBA) and two-dimensional static biomechanical analysis were automatized as two toolboxes in the proposed system to provide comprehensive WMSD risk assessment based on the kinematic data acquired from wearable inertial sensors. The effectiveness of the developed system was validated through a follow-up experiment among 20 young subjects when performing representative tasks in the heavy industry. The RULA/REBA scores derived from our system achieved high consistency with experts’ ratings (intraclass correlation coefficient ≥0.83, classification accuracy >88%), and good agreement was also found between low-back compression force from the developed system and the reference system (mean intersystem coefficient of multiple correlation >0.89 and relative error <9.5%). These findings suggested that the wearable inertial sensors-based automated system could be effectively used for WMSD risk assessment of workers when performing tasks in the workspace.

The aim of this study was to investigate the effect of different loading symbols and loading durations on online video viewers’ perception of waiting time. Sixty young adults participated in this study and their subjective ratings on waiting time perception for forty-eight different loading symbols (4 progress functions × 2 shapes × 2 embellishments × 3 durations) were obtained through a 7-point Likert scale. Each participant chose the best loading symbols in terms of waiting time perception at the end of the experiment. Results showed that duration and the progress function practically affect the viewers’ waiting time perception, and shape and embellishment do not. Loading symbols of power and inverse power progress functions are perceived as shorter than those of the repetitive and linear progress functions. It is recommended to show loading progress and use manipulated progress functions, and design factors such as shape and embellishment are considered to be less important for designing a better loading symbol. The findings of this study may serve as a useful input for video service providers and symbol designers in creating shortly perceived loading symbols.