• 대한인간공학회지
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• 제31권3호
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• pp.437-444
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• 2012

The purpose of this study was to suggest appropriate human model for ergonomic evaluation considering working postures on 3D space. Background: Traditionally extreme design rules have been widely utilized at the stage of designing products. Body size of 5th percentile and 95th percentile in stature has been generally selected for controllability and clearance evaluation, respectively. However, these rules had limitations in reflecting working posture in ergonomic evaluation. Method: In order to define working posture on 3D space, not only sagittal plane but also lateral plane was considered. Kinematic linkage body model was utilized for representation of working posture. By utilizing the anthropometric data of 2,836 South Korean male populations, the point cloud for end points of linkage models was derived. The individuals who were lacking in certain controllability were selected as human models for the evaluation. Result: In case of standing posture it was found that conventional approach is proper for all controllability evaluations. Contrary to standing posture, tall people had less controllability on control location below shoulder point in sitting posture. Conclusion: From the derived proper range on controllability, ergonomic evaluation rule was suggested according to working posture especially in standing and sitting. Application: The results of the study are expected to aid in selection of appropriate human model for ergonomic evaluation and to improve the usability of products and work space.

• 대한산업공학회지
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• 제28권2호
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• pp.216-222
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• 2002

The ergonomic human model can be considered as a tool for the evaluation of ergonomic factors in vehicle design process. The proper anthropometric data on driver's postures are needed in order to apply a human model to vehicle design. Although studies on driver's posture have been carried out for the last few decades, there are still some problems for the posture data to be applied directly to the human model due to the lack of fitness because such studies were not carried out under the conditions for the human model application. In the traditional researches, the joint angles were evaluated by the categorized data, which are not appropriate for the human model application because it is so extensive that it can not explain the posture evaluation data in detail. And the human models require whole-body posture evaluation data rather than joint evaluation data. In this study a postural evaluation function was developed not by category data but by the concept of the loss function in quality engineering. The loss was defined as the discomfort in driver's posture and measured by the magnitude estimation technique in the experiment using a seating buck. Four loss functions for the each joint - knee, hip, shoulder, and elbow were developed and a whole-body postural evaluation function was constructed by the regression analysis using these loss functions as independent factors. The developed postural evaluation function shows a good prediction power for the driver's posture discomfort in validation test. It is expected that the driver's postural evaluation function based on the loss function can be used in the human model application to the vehicle design process.

• 대한인간공학회지
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• 제24권1호
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• pp.37-41
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• 2005

Work related musculoskeletal disorders became a hot issue in Korea since many workers reported musculoskeletal disorder problems. Korean government enacted a law to require companies to take measures to prevent musculoskeletal disorders at work. This study found workers' WMSDs symptoms in squatting work posture which the rate of the occurrence was relatively high among work types to bring about WMSDs in railroad cars maintenance works and analyzed to compare the hazardous jobs in the industrial safety health law in South Korea with the caution jobs in Washington State in U.S. The hazardous jobs in South Korea were more effective in squatting work posture from this study result and this study data will be a great help to plan and carry out an effective prevention program about WMSDs.

• 대한인간공학회지
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• 제30권3호
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• pp.409-418
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• 2011

Objective: This study was performed to evaluate the child-care teachers' job in relation to physical work. Background: Child-care teacher is directly related to the quality of child care. And their physical activity is higher than general education teachers because the proportion of day care is high. But analyzes of child-care teachers' job burdens and the work environment associated with physical activity is not well established. Method: To conduct this study, the child-care teachers' job was classified into 18 physical works. After classification, posture was evaluated by ergonomic posture evaluation schemes of OWAS, RULA, REBA and evaluated for each physical part. Next, musculoskeletal subjective symptoms were analyzed. Results: The results showed the following: The highest assessment on the posture evaluation was "helping children to ride a school bus", "feeding: meal/snack", "brushing children's teeth" and "arrangement of nap-stuff". The rank of high-risk assessment on the neck/trunk/leg part was arranged by: "feeding: meal/snack", "helping children to ride a school bus", "making nap", "arrangement nap-stuff" and "brushing children's teeth". The rank of high-risk assessment on the upper limbs part was arranged by: "helping children to ride a school bus", "the bust - group activity", "meal/snack time - preparing, feeding, arrangement", "nap time - preparing, arrangement", "brushing children's teeth", and "using the toilet". According to the results of each musculoskeletal subjective symptom, teachers ordered the pain area as follows: waist, shoulder, leg/feet, and neck, and they showed more pain on trunk than the upper limbs. Conclusion: To sum up the results from ergonomic posture evaluation and a subjective symptom, the following are high working pressures: "feeding: meal/snack", "the bust - group activity", "making nap", "brushing children's teeth" with deep bending and waist twisting, "helping children to ride a school bus", "brushing children's teeth" with lifting shoulder; "meal/snack time - preparing, arrangement", "nap time - preparing, arrangement", and "using the toilet" with moving or an up-down position in their job. Application: The results of this study might be information for improvement of the child-care teachers' job environment.

• 대한안전경영과학회지
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• 제22권2호
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• pp.31-38
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• 2020

The study evaluated the accuracy and intra-rater reliability for OWAS (Ovako Working posture Analysing System), RULA (Rapid Upper Limb Assessment), REBA (Rapid Entire Body Assessment) to improve their evaluation accuracy and reliability. Participants (n = 163) with undergraduate degree were recruited in this study and trained for 6 hours about the ergonomic assessment methods. Ergonomic assessments were conducted using OWAS, RULA, and REBA for a representative work with dynamic posture found in manufacturing industries. The study compared action categories (overall level) and detailed evaluation scores for individual body part. Action categories of the participants significantly differed from the golden reference defined by ergonomic experts. The participants underrated or omitted scores for truck (37.4% of the participants) and legs (52.8%) in OWAS. Similarly, the participants underrated or omitted additional scores for all body parts except the hand and wrist in RULA (53.5%) and REBA (54.8%). On the other hand, the participants overrated scores for the hand and wrist in RULA (55.2%) and REBA (39.9%). The results found in this study can help of selecting focus points and parts during assessment and education to improve accuracy and reliability of the ergonomic assessment methods.

• 대한인간공학회지
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• 제30권3호
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• pp.419-426
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• 2011

Objective: The objective of this study was to evaluate a work of guards, using an ergonomic method(work analysis and posture analysis). Background: Most studies about guards were conducted in the field of medical, problems of shift, and the physical problems of old workers and social problems. But, guards consist of vulnerability group so it needs an ergonomic research in musculoskeletal disorders. Method: A head of an ergonomic estimation was work analysis(determination of combined task, work tool, work time and frequency of combined task) and posture analysis(upper body and lower body) of workers based on the video. Results: The result showed that combined task of guards was classification of patrolling, security, cleaning and waiting. The security indicated the highest ratio in the work time of combined tasks. The results of posture analysis for guards indicated high value in neutral. But, lower arm indicated high value in bending(left: 59%, right: 50%). Conclusion: The results of ergonomic methods indicated that guards' physical work load was not high during work, but comfortable work environment would be required for old guards. Application: If an ergonomic rule can be integrated into existing work environments, the risk of occupational injuries and stress will be reduced.

• 한국안전학회지
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• 제20권1호
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• pp.148-152
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• 2005

The purpose of this paper is to investigate risk factors and ergonomically improve the manufacturing lines of compressors for prevention of work-related musculoskeletal disorders, enhancement of productivity, and workers satisfaction We executed questionnaire survey, ergonomic risk factors investigation of manufacturing lines and ergonomic intervention of work methods, workplace and hand tools. The results of the questionnaire showed that $7.9\%$ of respondents were positive in WMSDs symptom survey. In ergonomic evaluation, the analysis methods such as RULA and NIOSH lifting equation were used and 28 processes in the lines were evaluated to be potentially hazardous. We ergonomically improved the processes to reduce potential WMSDs hazards : manual material handling, carts, work tables, transport methods, working posture and hand tools.

• 산업공학
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• 제11권2호
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• pp.125-137
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• 1998

A new vehicle design approach coupled with an ergonomic human model was proposed in the study. The seating package layout of a vehicle is very important to the driving comfort, and it has been one of the primary ergonomic research areas since the past 30 years. The diverse and interrelated design factors of seating package layout in the limited workspace make designers often neglect many parameters related with drivers which differ in their anthropometric characteristics. It is due to the lack of the proper tools by which the designer can easily apply several ergonomic design guidelines to the vehicle design. In this study. an iterative package layout procedure was developed, and the effectiveness of an ergonomic human model was examined in this procedure. A discomfort function was developed for the quantitative evaluation of the driving posture. This study clearly demonstrates that the package layout using an ergonomic human model is very helpful to improve the usability and driving comfort of the drivers or passengers.

• 산업공학
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• 제24권4호
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• pp.387-395
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• 2011

This study was aiming to examine work time, frequency, work environment, and postures of retail grocery store workers to evaluate the risk of musculoskeletal disorders. An ergonomic evaluation was conducted using job analysis and posture analysis. The four most time-consuming tasks were inspecting (27.4%), arranging (21.4%), cutting (17.6%), and displaying (15.6%). The height and length of the shelves evaluated in the field was inappropriate for workers. The most common posture was a standing posture with neutral back, and bent head, right upper arm, lower arms, and hands. Finally, this paper concluded that 'arranging,' 'cutting,' and 'displaying' seemed more stressful than other operations. The result of the ergonomic evaluation would contribute to design a better workspace in ergonomics.

• 한국안전학회지
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• 제14권4호
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• pp.168-175
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• 1999

The objective of this research is to review the ergonomic keyboard developed to prevent musculo-skeletal disorders from being occurred during keyboard work. It was studied by comparing it with the traditional keyboard after analyzing and comparing the typing performance and work advantages both the two keyboards. Twelve male subjects with no history of musculo-skeletal disorders participated in the experiment. The quantitative data such as typing speed, accuracy, performance time, and the number of typing errors were obtained from the HTT software that was adjusted for this experiment. RULA worksheet and the degrees of extension and ulnar deviation on right and left wrist were used to analyze the upper body postures. The experiment results showed that the typing performance of the ergonomic keyboard decreased a little, but no significant difference statistically, compared with that of the traditional keyboard. On the work posture, the ulnar deviation during typing decreased in case of the ergonomic keyboard. But, the wrist extension was increased unexpectedly. Therefore, it can be regarded as these results occur due to the shape of wrist rest and the overall height of keyboard on a table. As a result, the reconsideration and redesign on the ergonomic keyboard are requested.