The Japanese Journal of Ergonomics

Featured article

Volume 52 (2016) Issue 1 Pages 40-48

Posture Stability Evaluation Based on Maximum Reach and Working Posture on a Stepladder

Atsushi SUGAMA, Akihiro OHNISHI

A fall accident from a stepladder is often due to loss of balance while in a working posture. The purpose of this study was to evaluate posture stability, while standing on a stepladder, based on working posture and maximum reach distance. Ten male subjects reached forward as far as possible on a stepladder at shoulder height. The test involved combinations of 4 standing positions and 5 reach directions. The maximum reach distance on the horizontal plane, working posture, center of pressure (COP) location, and subjective assessment on posture instability were recorded. The horizontal distance from the center of a stepladder to the index fingertip was defined as the maximum reach distance, while COP location at these extreme distances determined the stability limit. The results showed that stability limit at two-steps below the platform was longer than that at one-step below the platform or on the platform. Maximum reach distance had no significant difference between on the platform and at two-steps below the platform. These results suggest that posture stability was improved at two-steps below the platform without a decrease of maximum reach distance.

Volume 51 (2015) Issue 5 Pages 358-364

Children's Comprehension of Hierarchical GUI Menu Operations

Fumiko SAKANO, Akira OKADA

The comprehension of hierarchical GUI menu operations was investigated in children in the process of developing their cognitive functions. Participants were 120 children aged 3-6 years. They were asked to select a target item presented on a computer screen, according to figures, colors, and patterns on menus constructed of two and three hierarchical structures. Their degree of comprehension was estimated on the basis of the success rate of selection tasks. For 3- to 5-year-old children, the success rate significantly increased with the two-structure menu than with the three-structure menu. Limited processing capacity of their short term memories, difficulty of voice-encoding, and undeveloped verbalization might have influenced their low success rates in the three-structure menu. The 6-year-old children had a success rate near 100%, which suggests that hierarchical menu images can be constructed in 6-year-old children as well as in adults. The points at which the success rate increased rapidly were observed both in the two- and three-structure menus. This suggests the existence of a critical period in the comprehension of hierarchical menus.

View the past featured articles

2018 Volume 54 Issue Supplement

S9-2　University-driven Ergonomics Research Collaboration Yoshihiro SHIMOMURA, Megumi SHIMURA, Yali XIA
1A1-4　Comparison of Relaxation Effect from Watching Images Between 2D and Head-Mounted Displays Yoshiki KOINUMA, Michiko OHKURA
[title in Japanese] [in Japanese], [in Japanese]
S11-2　An experience of applying the action checklist at Sozai industry workplaces Koya KISHIDA

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