Chi-ang Yu

Foot surface area database and estimation formula.

The purpose of this study is to establish a foot surface area (FSA) database and estimation formula based on 3-D foot scan data. For each gender, 135 subjects stratified in five statures and three body weights were drawn. The foot was measured using a high-resolution 3-D foot scanner, of which the precision and accuracy is within 1%. The FSA was computed by the triangular mesh summation method and five 1-D foot measurements were extracted automatically to be used as candidate estimators for FSA estimation formula. The results of the FSA measurements are tabulated on fifteen strata for the Male, the Female and the Total (the two genders combined). The comparison of these FSA measurements with previous studies shows that previous studies underestimated the FSA approximately 4.06% for the Total (for the Male, 6.93%; for the Female, 0.82%). Regression analyses using these five 1-D foot measurements were performed. The results show that foot-length and ball-girth are effective estimators of FSA for the total (FSA=1.043 x foot-length x ball-girth, R(2)=95.4%). A test on the necessity of gender-specific formula indicated that no gender-specific formula is needed, and the formula for the total is good for both genders.

Determination of hand surface area as a percentage of body surface area by 3D anthropometry

This study investigates the hand surface area (HSA) and palm surface area (PSA) percentages of body surface area (BSA). The HSA and PSA of 135 men and 135 women were measured by scanner and incorporated into an existing BSA database to derive %HSA/BSA and %PSA/BSA using five stature heights and three body weights in accordance with population distribution. Allowing for various degrees of specificity, the mean %HSA/BSA and mean %PSA/BSA were found to be 2.29% (0.24%) and 0.89% (0.09%), respectively. Gender and body weight group were significant factors.

Ergonomic Interventions in the Workplace: A Case Study

The purpose of this study was to assess the physical workloads for packing tasks in a printing ink manufacturing factory located in northern Taiwan, with an aim to lower the risk of musculoskeletal disorders (MSDs) among the workers. The BRIEF checklist and Key Indicator Method (KIM) were used to evaluate and identify the MSD risk factors associated with the ink packing tasks. The data collected include material weights, work posture, work pace, vertical distances, vertical lifting displacement, and lifting frequency. The ink-filling operator averagely filled 2000 1-kg ink cans per day and the ink-packing operator totally lifted 4166 times per day and the average lifting weight was 1.44 kg/lift. The BRIEF analysis results show that both of the operators have high possibility of developing MSDs. The KIM risk scores were evaluated as 40 (median high load) and 50 (high load) for the ink-filling and ink-packing operators, respectively. To reduce MSD risks for this work, a redesign worktable was suggested to replace the original one. This hardware intervention can allow the operators to move the ink cans more smoothly and efficiently without bending their backs as they pack the cans. Further, the estimated KIM risk scores were reduced to 20 and 30 for the ink-filling and ink-packing operators, respectively. This suggested change has been adopted by the ink company and will be implemented in the packing area.