• Journal of the Ergonomics Society of Korea
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• v.32 no.1
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• pp.145-152
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• 2013

Objective: The aim of this study is to develop an ergonomic office chair that has an alarm function for the unbalanced sitting postures. Background: Contrary to expectation, it is reported that office workers sit on their chairs much more in unbalanced postures during daily work. Even though an office worker uses an ergonomically good-designed chair and begins their work in a good sitting posture, his/her posture is likely to shift to the unbalanced bad posture. Therefore, a posture alarm system would be very helpful in keeping office workers' good postures. Method: We developed a prototype chair with four load cells under a seat pan and one load cell beneath a backrest. Through some experiments, we set the criteria for unbalanced bad postures then implemented the criteria into the alarm system of the prototype chair. The chair called e-BASE chair could detect unbalance postures and show alarms for chair users. We also enhanced back support by developing a step-wised folding backrest. Results: The e-BASE chair showed better performance in interface pressure distributions and balanced posture ratio in VDT work. Conclusion: The ergonomic chair with posture alarm function(e-BASE chair) was developed. It showed better performance in seat pressure distribution and in keeping good posture during office work. Application: The posture alarm system and folding backrest can be applied to the new models of office chair.

• Journal of Auto-vehicle Safety Association
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• v.12 no.1
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• pp.52-61
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• 2020

In recent years, the increasing interest in health-care requires the industrial products to be well-designed ergonomically. In the commercial vehicle industry, several researchers have demonstrated the driver's posture has great effect on the orthopedic desease such as fatigue, back pain, scoliosis, and so on. However, the existing sensor systems developed for measuring the driver posture in real time have suffered from inaccuracy and low reliability issues. Here, we suggest our smart vehicle seat system capable of real-time driver posture monitoring by using the air bag sensor package with high sensitivity and reliability. The ergonomic numerical model which can evaluate a driver's posture has been developed on the basis of the human body segmentation method followed by simulation-based validation. Our experimental analysis of obtained pressure distribution of a vehicle seat under the different driver's postures revealed our smart vehicle system successfully achieved the driver's real-time posture data in great agreement with our numerical model.

• Journal of Auto-vehicle Safety Association
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• v.15 no.3
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• pp.59-65
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• 2023

As advanced driving assistance system (ADAS) and autonomous driving performance continue to improve, existing crash accidents and crash types are changing. Accordingly, the collision angle and the seating posture of the occupant are changed. It is necessary to study how the occupant injury mechanism changes according to these different crash types. In this regard, a representative crash test mode was derived when the automatic emergency braking system (AEB), one of the autonomous driving performance, was applied to the representative car-to-car crash scenario in Korea. The derived crash test mode was used to analyse the mechanisms of collision injuries according to both impact angle and the occupant seating posture (reclined seat-back angle). The results obtained through this study can be utilized as reference data for the development of new crash evaluation methods and improvements in crash restraint systems for enhancing crash safety.

• Journal of Auto-vehicle Safety Association
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• v.15 no.4
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• pp.48-57
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• 2023

With the advance of autonomous vehicle technology various sitting posture is possible like relax position (inclined seating posture). Parametric study was done with MADYMO, a mutibody dynamics solver, to investigate the effect of sitting posture in different frontal crash modes, full frontal, 40% offset, and angled rigid barrier crash as well as various impact speeds. Hybrid III 50th male and 5th female dummies were used to figure out the difference induced by occupant weight and dimension. Restraint system parameters complying to current safety protocols like NCAP are studied if they still work effectively in relax position which is feasible with autonomous vehicles.

• Journal of the Korea Safety Management & Science
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• v.11 no.4
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• pp.77-83
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• 2009

The purpose of this study was to examine the relative effectiveness of immediate feedback and informational prompt on safe sitting behaviors that may cause VDT syndromes. Participants were three white color workers and an ABCB within-subject design was adopted. Safety Posture System was developed specifically for the present study. The system could detect participants' unsafe sitting postures using sensors and provide feedback and prompt on the computer monitors. The results indicated that both immediate feedback and informational prompt considerably increased safe sitting behaviors. More importantly, the immediate feedback was more effective than the informational prompt in increasing safe sitting behaviors.

• Journal of the Korean Society of Safety
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• v.26 no.6
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• pp.97-103
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• 2011

This study compared the effects of different frequencies of self-monitoring on safe sitting postures. Participants were four office workers. The dependent variable was the safety percentage for four body positions. The independent variable was self-monitoring frequency: high and low self-monitoring frequencies. Results showed that the safety percentage increased when self-monitoring was introduced. However, the effects of the two different self-monitoring frequencies on safe performance were not statistically different.

• Journal of the Korea Safety Management & Science
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• v.23 no.2
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• pp.25-30
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• 2021

The possibility of developing musculoskeletal disorders increases with the length of service of the worker. Musculoskeletal disorders can occur when performing repetitive and forceful movements. Therefore, Cargo drivers operate repeatedly in the wrong posture for a long time. When loading and unloading a cargo, the cargo driver works repeatedly with force. Cargo operators are also exposed to musculoskeletal disorders in the working environment due to poor posture and repetitive movements. In this study, we are going to conduct a study on the level of awareness and prevention of the possibility of musculoskeletal disorders in cargo drivers for long periods of time. As a result of the study, the factors that cause musculoskeletal disorders in each group can occur during the long-term operation and preparation of drivers.

• Journal of Korean Society of Forest Science
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• v.110 no.2
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• pp.210-216
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• 2021

Musculoskeletal disorders affect workers' safety in most industries, and forest operations are classified as a musculoskeletal burden according to the Occupational Safety and Health Act in South Korea. In particular, felling and delimbing operations are mainly conducted by manpower, and then, it is necessary to evaluate ergonomic risk assessment for safety of felling and delimbing workers. Three ergonomic risk assessment methods, such as Ovako Working posture Analysis System (OWAS), Rapid Upper Limb Assessment (RULA), and Rapid Entire Body Assessment (REBA), are available for assessing exposure to risk factors associated with timber harvesting operations. Here, three ergonomic risk assessment methods were applied to examine ergonomic risk assessments in chainsaw felling and delimbing operations. Additionally, exposure to risk factors in each method was analyzed to propose an optimal working posture in felling and delimbing operations. The risk levels of these operations were evaluated to be highest in the RULA method, followed by the OWAS and REBA methods, and most of the exposed working postures were examined with a low-risk level of two and three without requiring any immediate working posture changes. However, two significant working postures, including the bending posture of the waist and leg in felling operation and standing posture on the fallen trees in delimbing operation, were assessed as the high-risk level and needed immediate working posture changes. Low-risk work levels were examined in the squatting posture for felling operation and the straightened posture of the waist and leg for delimbing operation. Moreover, the slope in felling operation and the tree height in delimbing operation significantly affected risk level assessment of working posture. Therefore, our study supports that felling and delimbing workers must operate with low-risk working postures for safety.

• Journal of the Korea Safety Management & Science
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• v.14 no.2
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• pp.11-22
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• 2012

The purpose of this study was to compare drivers' postures with different car pedal systems and skilled levels. Fourteen subjects participated in this experiment and for three-dimensional analyses, six cameras (Proreflex MCU-240, Qualisys) were used to acquire raw data. The parameters were calculated and analyzed with Visual-3D. In conclusion, the patterns of pelvic, hip, knee and ankle joint angles were different as to pedal systems and skilled levels, and distal joints ROA pelvis have large angles. ROA(range of angle) of a double pedal system was small, but ROA of a single pedal system was large. These findings suggested that we should improve a present single pedal system.

• Journal of the Ergonomics Society of Korea
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• v.32 no.5
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• pp.475-480
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• 2013

Objective: In this study, virtual reality was adopted to consider ergonomic factors in yacht design. Virtual human which is the same actual human was created in virtual environment using Digital Human Modeling which has been used in the manufacturing communities to design better workplaces and maximize the safety of workers. Background: During the past 40 years yachting has expanded from being, generally speaking, a minority sport - too expensive for the large majority of people - into a major recreational activity practiced by millions all over the world. Many new yacht designs have appeared and number of professional, as well as amateur designers has increased steadily. But they had not considered ergonomic factors in yacht design. Method: Worker's posture, traffic line and workload had been analyzed in sailing yacht. After the caution level was evaluated, we pointed out clues which had high workload and interference. To reduce workload, we applied ergonomic principles for improving working conditions and environments in Digital Human Model. Results: We found the space problems and workload of postures. Conclusion: (1) Unnatural posture of crews was sustained. (2) Workload that occurs in the human body was overloaded. (3) Crew's work space was very narrow. Application: This study will be applied the new ergonomic design of yacht.