• Journal of the Ergonomics Society of Korea
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• v.23 no.4
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• pp.45-56
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• 2004

The purpose of this study is to evaluate perceived discomfort of working postures in terms of upper body (back, shoulder, and elbow) flexions when an external load varies. Eighteen subjects participated in an experiment of appraising perceived discomfort of varying upper body postures with three levels of external loads given. The ANOVA results showed that the perceived discomfort of upper body postures was significantly affected by the external load. It was also apparent that the interactions between external load and upper body posture were significant (p< 0.001). The result implies that a new posture classification scheme for workload assessment methods may be in need to reflect such interactions between external load and upper body posture. In order to support the statement, a regression model of perceived discomfort of upper body postures obtained from the experiment was developed and compared to that of perceived discomfort of seven work-related postures found in automobile assembly operations. The correlation coefficient between predicted and actual values of perceived discomfort was about 0.96. It is expected that the result help to properly estimate the body stress resluting from worker's postures and external loads and can be used as a valuable design guideline on preventing work-related musculoskeletal diseases in industry.

• 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 the Institute of Convergence Signal Processing
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• v.24 no.1
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• pp.15-20
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• 2023

In general, maintaining an incorrect sitting posture for a long time is widely known to adversely affect the spine. Recently, several researchers have been interested in the causal relationship between incorrect sitting posture and spinal diseases, and have been studying methods to precisely measure changes in sitting or standing posture to prevent spinal diseases. In previous studies, we have developed a sensor device capable of measuring real-time posture change, applied a momentum calculation algorithm to improve the accuracy of real-time posture change measurement, and verified the accuracy of the postural change measurement sensor. In this study, we developed a posture measurement and analysis device that considers changes in the center of body pressure through the developed sitting pressure measurement, and it confirmed the sensor as an auxiliary tool to increase the accuracy of posture correction training with improving the user's visual feedback.

• Fashion & Textile Research Journal
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• v.13 no.5
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• pp.728-733
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• 2011

U.S. apparel brands are being imported to Korea more than any other country's apparel brands. Against this backdrop, this study intends to verify the fitness of U.S. apparels for Korean people in terms of size. To this end, the authors selected 25 American and 25 Korean women in their twenties and studied the differences of these two groups with regard to the size of their lower body parts. In addition, the authors analyzed how the size of each part of the lower body changes according to different postures. All the study subjects were required to be able to wear medium-sized pants of the U.S. apparel. The results of the present study are shown below. The American women were bigger than the Korean counterparts in leg length, hip circumference, thigh circumference, and all height-related sizes. However, the Koreans were bigger than their peers in lengths from waist to crotch; crotch length, body rise and the length from front waist point to hip line. Standing posture was used as a yardstick, when the changes in size according to the different postures were examined. The results indicate that hip and knee circumferences increased in the sitting posture. In particular, hip circumference significantly increased in the American women group. Regarding length-related sizes, increases and decreases in sizes for different lower body parts differed according to the posture. For a walking posture with ordinary strides, the front crotch length decreased while the back crotch length increased. This tendency was more notably observed for Korean women. The American woman clearly showed a decrease in outside leg length for all postures. The Korean women obviously presented an increase in the front center leg length for the sitting posture and for the posture where the knees were bent at $120^{\circ}$. The length from the front waist point to the hip line significantly declined in the Korean woman for the sitting posture and for the walking posture with ordinary strides.

• Journal of computational fluids engineering
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• v.21 no.3
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• pp.71-76
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• 2016

In speed skiing, aerodynamic forces play an important role in determining performance of the skier. To predict aerodynamic effects of the posture of the skier on alpine downhill skiing, we constructed equation of motion of the skier and performed the corresponding CFD simulations. Comparing drag and lift of three different skier postures, it has been shown that drag decreases significantly by tucking upper body to lower body and stretching arms forward. Also, aerodynamic lift which worked as downforce in standing posture worked upward in tuck posture, reducing friction force between snow and ski. This indicates that tuck posture have advantages over standing posture in dual mechanism, namely by reducing drag and also increasing lift. By this two-dimensional initial study we could reveal the general tendency of the aerodynamic force over the skier's body. This study not only provides a theoretical foundation for the athletes to understand the aerodynamic effects of skier postures but also shed a light on towards more accurate and rational three-dimensional CFD simulation of skiers in the near future study.

• Journal of Korean Medicine Rehabilitation
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• v.24 no.4
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• pp.177-185
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• 2014

Objectives This study analyzed the correlation between body parameters measured using X-ray and Chuna posture analysis system to determine their clinical value in diagnosing and evaluating skeletomuscular diseases. Methods X-ray and Chuna posture analysis system were performed for 105 patients to measure physical characteristics such as Interacromial angle, Pelvic obliquity angle, Structural leg length discrepancy (SLLD), Midpatella-midtalus angle (MMA) and Q-angle, Anterior head translation (AHT), Anterior superior iliac spine to posterior superior iliac spine angle (ASIS-PSIS angle), Interscapular angle, Scoliotic angle and Cobb's angle. Statistical analysis using statistical analysis techniques and Pearson correlation coefficients was performed to assess the body parameters obtained by X-ray and Chuna posture analysis system. Results Significant correlations were observed between the values for Interacromial angle, Pelvic obliquity angle, SLLD, MMA and Q-angle, AHT, ASIS-PSIS angle, Interscapular angle, Scoliotic angle and Cobb's angle obtained by X-ray and Chuna posture analysis system. Significant correlations were also observed between right MMA and left Q-angle as well as between left MMA and right Q-angle. Conclusions Chuna posture analysis system can be used instead of X-ray measure body parameters and perform posture analysis in clinical practice. This study's findings are expected to serve as a basis for further research on the clinical application of Chuna posture analysis system.

• The Journal of the Society of Korean Medicine Diagnostics
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• v.10 no.2
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• pp.121-131
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• 2006

Background : As each human has a look in the face of oneself, he or she has a look of him or herself in the shape of the body also. And for the shape of the body which gives a big clue in diagnosis in musculoskeletal disorders. Therefor many means are used and developed for diagnosis through body shape or posture analysis for musculoskeletal disorders. X-ray, CT, MRI has been used for diagnosis through image in this way to tell about the inside of the human body. On the other side, moire topography was used for information about the exterior of the human body, but yet only minimal information such as the number of contour lines in each side was available. Therefor there were a few studies to use moire topography or other methods to get information about the surface of the human body in numeric values. The instrument used in this study which is a laser projection moire, is another trial to get numeric data about the surface of the human body. The instrument is composed of laser projector and a computer software to recompose and analyse the image data into depth, height, angle and length. Objectives : The study was focused on whether the instrument is reliable for clinic use, and to seek the proper environment and posture for the examination, and among the data the software provides, which items are more reliable and useful. Methods : For reproductivity and repeatability, 4 testers tested 2 persons. And to how if the body shape changes according to the posture and which posture gives the most reliable data, the test was performed in 6 different positions. Results : Result, the instrument showed sufficient repeatability and reproductivity for clinical use. And among the items the software provides, the length of the back, the angle of the back in the sagittal and coronal plane showed reliable results. And there was difference in the results according to the posture, and Therefor, in following studies using this instrument or similar type of posture analysing instruments, the length of the back, the angle of the back in the sagittal and coronal plane could be reliable item to use.

• Journal of the Ergonomics Society of Korea
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• v.24 no.3
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• pp.43-52
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• 2005

A two-dimensional posture measurement system was developed to evaluate the risks of work-related musculoskeletal disorders(MSDs) easily on various conditions of work. The posture measurement system is an essential tool to analyze the workload for preventing work-related musculoskeletal disorders. Although several posture measurement systems have been developed for workload assessment, some restrictions in industry still exist because of its difficulty on measuring work postures. In this study, an image recognition algorithm was developed based on a neural network method to measure work posture. Each joint angle of human body was automatically measured from the recognized images through the algorithm, and the measurement system makes it possible to evaluate the risks of work-related musculoskeletal disorders easily on various working conditions. The validation test on upper body postures was carried out to examine the accuracy of the measured joint angle data from the system, and the results showed good measuring performance for each joint angle. The differences between the joint angles measured directly and the angles measured by posture measurement software were not statistically significant. It is expected that the result help to properly estimate physical workload and can be used as a postural analysis system to evaluate the risk of work-related musculoskeletal disorders in industry.

• Journal of International Academy of Physical Therapy Research
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• v.6 no.1
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• pp.809-814
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• 2015

This study was conducted to identify how a flexi-bar exercise influences body alignment and balance in adults who have asymmetry in their right or left body. In total, 20 participants were separated into the experimental group and the comparison group. Those in the experimental group participated in a flexi-bar exercise for 6 weeks and based on the coronal plane before and after exercise, their body alignment and balance were measured behind the body. The result was those who had participated in a flexi-bar exercise significantly improved their angle of acromion on both sides, the difference in the angle and height of the posterior superior iliac spine on both sides(p<.05), and the balance of the center sagittal plane(p<.05). Through this study, it could be said that participating in a flexi-bar exercise would improve postural alignment and balance of the shoulder and pelvis in adults with asymmetric posture.

• Proceedings of the ESK Conference
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• 1997.10a
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• pp.437-440
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• 1997

The association of poor body postures with pains or symptoms of musculoskeletal discorders has been reported by many researchers. An ergonomic evaluation of postural stresses as well as biomechanical stresses is also important especially when a job involves highly repetitive or prolonged poor body postures. The human body is divided into five parts: shoulder/upper arm, lower arm/wrist, back, neck, lower extremities. A work-sampling based macropostural classification system was developed to characterize various postures in this study. Application of the posture classification schema developed in this study to 7 automobile assembly tasks showed that the schema can be used as a tool to didntify the operation and tasks involving highly stressful body postures. This posture classification schema can also be applied as a basis for quantitive evaluating the workload of manual task.