Myung-Chul Jung

The Identification of Uncomfortable Operating Device of Truck by Delphi Survey and AHP

As the industry develops, the growth of the transportation industry is steadily increasing. A truck is a means of occupying most of the land transport. Therefore, the ergonomic design considering the usability and safety of the truck has become as important as mechanical performance and quality. Thus, it is important to based user experience systematically find uncomfortable operating device of truck. Operating devices of truck commonly applied to most trucks were selected through literature surveys and user interviews, and their discomfort was evaluated by Delphi survey for 40 participants. Then, operating devices of truck were prioritized in terms of discomfort by using AHP (Analytic Hierarchy Process) analysis. The uncomfortable operating devices of truck found in this study can be useful for drivers engaged in transportation business and truck improvement. †

The Evaluation of Lower-limb Muscular Fatigue during Walking on Industrial Grating Type

Industrial grating has been widely used the work surface of manufacturing, plants, and shipyards due to excellent drainage and durability. The purpose of this study is to evaluate the localized muscle fatigue in lower limb by the grating type during walking. Six subjects were male industrial workers who participated in this study. This study considered four independent variables which were grating type, bar type, spacing and muscle. Surface electromyography signals from tibialis anterior (TA), peroneus longus (PL), gastronemius medialis (GM), and gastrocnemius lateralis (GL) were recorded to determine muscle fatigue. To assess fatigue, mean power frequency (MPF) drop rate of each experimental condition was obtained by using initial MPF (the initial 10 second) and last MPF (the last 10 second) and defined by percent decrease. As a results of Friedman test, grating type showed statistically significant difference (p=0.0317). The MPF drop rate of steel grating analyzed significantly higher 1.5%p than top grating. There were not significantly differences in bar type (p=0.0758), spacing (p=0.7630), and muscle (p=0.2803). It means that top grating evaluated low muscle fatigue than steel grating. That is why top grating should be not only having higher walking stability but also psychological safety due to a firmly structure and less exposed under grating. This study could be recommended to ergonomic work surface by grating to improve walking stability and safety.