Physical workload reduction is a significant factor in product design. However, experimental bioinstrumentation measurements involve substantial time and costs. This study proposed a simulation based ergonomic design method with digital human modeling (DHM) to accomplish efficient ergonomic product design. DHM simulation was applied to evaluate the joint moment ratios (JMRs). The product design for physical workload reduction was formulated as a minimization of the average and maximum JMRs to determine the optimal solution. The proposed method was applied to a problem of designing the forward distance of a handrail to support the sit-to-stand (STS) movement. The STS motion, the force exerted on the handrail, and the subjective perceived workload were measured for nine subjects. The STS motions and exerted force of the DHMs were predicted from the measured data, and physical workload simulation was performed with multiple DHMs to reflect anthropometric diversity. The response surfaces of the average and maximum JMRs were predicted as functions of the forward distance, and Pareto frontiers of each DHM condition were determined. The findings revealed that there were no trade-offs between the average and maximum JMRs, and that the optimal forward distance was in the range of 345-400 mm.

Approximately 60％ of accidents that happen on railway platforms in Japan resulting in injury or deaths are caused by drunken passengers. This study was designed to identify patterns of falls from platforms experienced by drunken passengers, as well as premonitory behaviors before falls and before making contact with moving train cars. Images collected from security cameras recording such accidents were analyzed. Results indicated （1） patterns of falls experienced by drunken passengers just before accidents could be classified into three types. （2） Premonitory behaviors displayed by drunken passengers on platforms and in concourses before having an accident could be classified into five types, and we calculated the incidence of these behaviors. Furthermore, 90％ of drunken passengers fell, or made contact with moving train cars after a few seconds of commencing to walk. It is suggested that station staff who observes drunken passengers displaying premonitory behaviors should call out to them and ensure their safety.

This study aims to develop a questionnaire to assess the interactive system based on user experience（UX）including usability and utility. The questions are the result of discussion and alpha version trial performed by ergonomics experts, psychologist, UX designers, and quality engineers. The alpha version was based on UX concepts and UX factors obtained from related standards, papers, previous research, and analysis of user episodes. Finally we developed the questionnaire beta version that consist of 19 questions including usability, utility, and empathy aspects. We are using the questionnaire in our practice and continue improving it while obtaining continuous feedback.