• IE interfaces
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• v.11 no.2
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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.

• Journal of Biomedical Engineering Research
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• v.45 no.2
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• pp.75-80
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• 2024

This research investigates the influence of chair tilt functionality on biometric signals and user comfort, addressing the ergonomic challenges posed by modern sedentary lifestyles. Through an experimental study involving eight male participants, the impact of chair tilt on electromyography (EMG), heart rate, metabolic rate, pressure distribution, and distance between the lumbar spine and the lumbar support part of the chair was measured across different seating postures. The study utilized chairs with both synchronous and non-synchronous tilt mechanisms to explore how adjustments in chair design affect user comfort and physiological responses during prolonged sitting. Key findings suggest that chair tilt functionality can significantly reduce muscle activity and energy expenditure, enhancing user comfort and potentially mitigating health risks associated with prolonged sedentary behavior. Notably, the study revealed a preference among participants for chairs that aligned the rotational center of the tilt with the hip joint, highlighting the importance of this ergonomic feature in enhancing user comfort. Additionally, the research proposes a novel methodology for assessing seating comfort through the analysis of both biometric and physical signals, providing valuable insights for the development of ergonomic chair designs focused on user health and comfort.

• Journal of Korean Institute of Industrial Engineers
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• v.41 no.1
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• pp.74-78
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• 2015

A bus seat is required to be ergonomically designed in terms of its shape and physical properties to increase seating comfort. The present study is intended to develop a systematic bus seat evaluation protocol based on seating comfort. A total of 48 participants evaluated 12 parts (seat belt, recliner, armrest, headrest, upper-back support, lumbar support, seatback bolster, seatback overall, hip support, thigh support, seatpan bolster, and seatpan overall) of 12 bus seats with 17 subjective comfort measures (e.g., convenience of control, suitability of size, and overall comfort). Lastly, ergonomic features of shape and physical properties of each seat part were identified based on the subject evaluation analysis results. The developed bus seat evaluation protocol can be applied to evaluate various types of seats.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.874-881
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• 2011

Driver's cab shall be designed ergonomically to provide the comfort for a driver to gather the information from the equipments and to operate the equipments effectively. The typical three design factors effected on the comfort are the access of driver's cab, freedom of movement inside the cabs and visibility condition. All control equipments shall be arranged so that those which are most often used or are of critical importance are the most convenient to the driver. The layout of driver's cab shall maximize the use of available space to be rugged and easily maintained. The visibility for the running direction along the track shall be secured. The visibility condition apply the seating position of the driver. Not only the environment condition(temperature, humidity, rattle, etc) but also the construction of driver's cab can be ergonomic design factor.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.8 no.1
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• pp.59-64
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• 2015

This study focuses on the dimensions of tractor seat, which is one of the important link between the tractor and the operator based on ergonomic approach in the design process. 7 anthropometric data sets were introduced from Korean and US anthropometric database for adult male and female including length of buttock to back of knee (sitting), height of lowest point of shoulder blade (sitting), underside elbow height (sitting), and so on. Design factor for the tractor seat included dimensions of seating surface, dimensions of backrest surface, and the location of armrest. The shape of spinal curve and clothing correction should be also considered during the design process. The result of this study can be used as a guideline for the design process of tractor seat.

• Journal of Korean Institute of Industrial Engineers
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• v.28 no.2
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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.

• Journal of Biomedical Engineering Research
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• v.44 no.2
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• pp.157-165
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• 2023

The purpose of this study was to evaluate the importance of developing slim seats with ergonomic design to improve seat comfort and expand the interior space. Two seats were used for the experiment: a sample seat designed based on hip shape and spinal alignment and a normal seat with a flat design without curves. Subjects sat in both the sample seat and a normal seat applied to the vehicle simulator and the experiment was conducted. The next part of the experiment was conducted in two different postures: a driving posture and a relaxed posture. The subjects filled out a comfort questionnaire immediately after sitting and after 30 minutes. The results showed that the comfort in the sample seat was found to be more comfortable than the normal seat. However, no significant difference was noted for the relaxation posture. Pressure distribution was also recorded immediately after sitting and after 30 minutes. In the case of pressure distribution, it was confirmed that the pressure in the sample seat was more evenly distributed in both the driving and relaxed postures than in the normal seat. The results showed that the ergonomically designed sample seat greatly improved seating comfort and pressure distribution compared to the normal seat, which is a general vehicle seat design.

• Journal of the Ergonomics Society of Korea
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• v.29 no.1
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• pp.61-66
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• 2010

The objective of this paper is to study the usability of the ingress/egress of elderly people, and analyze the physiological workload electromyography (EMG). We investigated the factors of discomfort while the elderly people are using the ingress/egress. Experiments were performed using a seating buck with 22 elderly participants (over 65 years old). The results showed that different muscles are activated during ingress and egress. A system called "easy access" was found which helps to access easily when a driver gets into a car. The current easy access was compared a newly proposed one. It was found that elderly people use less muscle during in/egress in the new easy access system.

• Journal of the Ergonomics Society of Korea
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• v.34 no.2
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• pp.151-165
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• 2015

Objective: This study aims to develop and scientifically investigate the efficacy of the Spine S-curve Reactive Backrest that responds to the spine curvature of the user when seated, and maintains and enhances the natural S-curve of the lower back, thereby helping to relieve fatigue, correct posture and prevent spine deformities. Background: The focus of current development, design guidelines and/or standards for office chairs is mainly placed on the chair's dimensions, incline angle, adjusting features and lumbar support. Research and development was called for developing a chair backrest that maintains and improves the S-curve of the full spine. Method: The Spine S-curve Reactive Backrest was ergonomically designed to maintain correct posture and enhance user comfort. When leaned on, the backrest responds to the user's spine line and the whole lower back sits closely against the backrest, thereby aligning the user's lower back and backrest as one to maintain and improve the natural S-curve formation of the spine. In order to evaluate the efficacy of the newly designed chair (new design) and the comparison target (chair), five male college students of standard body type with normal spine curvature were selected as test subjects, and a motion analyzer and electromyography were utilized to measure S-curve and erector spinae muscle activity when seated. Results: The spine S-curve was better maintained and improved when sitting in the new design than in the comparison chair. Particularly notable was the greater displacement gap of the thoracic spine than the cervical spine, and also that of the lumbar more than the thoracic spine, with the increase of the backrest tilting angle. Furthermore, the electromyogram results showed the new design caused a lower fatigue level of the erector spinae muscles compared to the comparison chair, and also earned a higher preference in the subjective opinion results. Conclusion: The newly designed chair in this study responds to the user's spine curvature and maintains and enhances the lower back's natural S-curve, and thereby relieves fatigue, promotes better posture, and helps to prevent spine deformities better than existing office chairs. There is a need to widely introduce and supply this new design. Application: The new design is applicable to office and student chairs, and is expected to improve concentration and work efficiency.

• IE interfaces
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• v.23 no.2
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• pp.100-107
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• 2010

For proper ergonomic evaluation using a digital human model simulation (DHMS) system such as $RAMSIS^{(R)}$, the postures of humanoids for designated tasks need to be predicted accurately. The present study (1) evaluated the accuracy of driving postures of humanoids predicted by RAMSIS, (2) proposed a method to improve its accuracy, and (3) examined the effectiveness of the proposed method. The driving postures of 12 participants in a seating buck were measured by a motion capture system and compared with their corresponding postures predicted by RAMSIS. Significant discrepancies ($8.7^{\circ}$ to $74.9^{\circ}$) between predicted and measured postures were observed for different body parts and driving tasks. Two methods (constraints addition and user-defined posture) were proposed and their effects on posture estimation accuracy were examined. Of the two proposed methods, the user-defined posture method was found preferred, reducing posture estimation errors by 11.5% to 84.9%. Both the posture prediction accuracy assessment protocol and user-defined posture method would be of use for practitioners to improve the accuracy of predicted postures of humanoids in virtual environments.