• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.8
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• pp.1952-1966
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• 1994

The body segment parameters of twelve young male Korean were measured to compare with the results of foreign cadaver studies. A human body was assumed to have fourteen body segments. The mass of each segment was measured with a water immersion test and the mass center of a segment was determined on the balance platform by changing postures. In the case of Korean, because of the difference in body proportion, the mass center of whole-body is located further from the distal end of head(Korean : 44.9% vs. Caucasian : 41.2%), and the mass center of each segment also located in different proportional locations. The existing regression equations, which can estimate segment mass based upon the anthropometric dimensions, estimates segment mass (the mass of shank) for Korean with 13% error. Therefore, it is not recommended to estimate the mass, and the moment of inertia of body segment of Korean based on the existing equations. However, the density information of body constituents was similar enough to apply it to Korean density. It was validated by the comparison between the results of the direct immersion method and 3-dimensional volume reconstruction of segment form the cross sectional images of CT-scan. The average body density measured form twelve subjects was $1.035{\;}kg/m^3$ and showed deceasing trendency.

• 한국HCI학회:학술대회논문집
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• 2007.02c
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• pp.326-333
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• 2007

To simulate solid dynamics,a we must com-pute the mass, the center of mass, and the products of inertia about the axes of the body of interest. These mass property computations must be continuously re-peated for certain simulations with rigid bodies or as the shape of the body changes. We introduce a GPU-friendly algorithm to approximate the mass properties for an arbitrarily shaped body. Our algorithm converts the necessary volume integrals into surface integrals on a projected plane. It then maps the plane into a frame-buffer in order to perform the surface integrals rapidly on the GPU. To deal with non-convex shapes, we use a depth-peeling algorithm. Our approach is image-based; hence, it is not restricted by the mathematical or geometric representation of the body, which means that it can efficiently compute the mass properties of any object that can be rendered on the graphics hardware. We compare the speed and accuracy of our algorithm with an analytic algorithm, and demonstrate it in a hydrostatic buoyancy simulation for real-time applications, such as interactive games.

• Proceedings of the IEEK Conference
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• 2002.07b
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• pp.1216-1219
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• 2002

It is understood so far that the center of mass does not make any linear movement from the rotatory movement of a rigid body in the closed system. However, it has been found that the center of mass of the system could make a closed linear movement due to production of an instantaneous center of mass by the Coriolis force in the rotatory movement of a rigid body in the closed system. The nature of the closed linear movement in the non-inertial system and that of the open movement in the inertial system are different from each other. That is, the closed movement is described like the time integration of frictional forces, which is different from the open movement usually considered and described like the time integration of external forces. It is shown in this paper that the Coriolis forces, called a fictitious force in the classical mechanics, is similar to the frictional force so that it causes to move the center of mass of a closed system. In this paper, following an explanation of the closed linear movement of a non-inertial system and the open movement of an inertial system, the source of the closed linear movement phenomenon of a rotatory rigid body is presented.

• Journal of Korean Academy of Nursing
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• v.42 no.4
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• pp.517-524
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• 2012

Purpose: To compare and confirm the impact of prepregnancy body mass index on pregnancy outcome in women with a singleton conceived by assisted reproductive technology and spontaneously conceived pregnancy. Methods: A sample of 165 and 247 pregnant women with and without assisted reproductive technology were retrospectively recruited from electronic medical charts of C hospital. Results: There were significant differences between the two groups for maternal age, paternal age, length of marriage, prepregnancy body mass index, parity, spontaneous abortion experience, and preterm delivery. A prepregnancy body mass index of ${\geq}25$ was associated with higher risk for maternal and neonatal complication in the assisted reproductive technology group. Conclusion: The results indicate that a higher prepregnancy body mass index is associated with increased risks for adverse pregnancy outcomes for women using assisted reproductive technology. So these women need appropriate care to compensate for the risk.

• Tuberculosis and Respiratory Diseases
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• v.72 no.5
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• pp.433-440
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• 2012

Background: The pulmonary function test is the most basic test method to diagnosis lung disease. The purpose of this study was to research the correlation of the body mass index (BMI), the fat percentage of the body mass (fat%), the muscle mass, the fat-free mass (FFM) and the fat-free mass index (FFMI), waist-hip ratio (WHR), on the forced expiratory volume curve. Methods: Between March and April 2009, a total of 291 subjects were enrolled. There were 152 men and 139 female (mean age, $46.3{\pm}9.92$ years), and they were measured for the following: forced vital capacity (FVC), forced expiratory volume at 1 second ($FEV_1$), and forced expiratory flow during the middle half of the FVC ($FEF_{25-75}$) from the forced expiratory volume curve by the spirometry, and the body composition by the bioelectrical impedance method. Correlation and a multiple linear regression, between the body composition and pulmonary function, were used. Results: BMI and fat% had no correlation with FVC, $FEV_1$ in male, but FFMI showed a positive correlation. In contrast, BMI and fat% had correlation with FVC, $FEV_1$ in female, but FFMI showed no correlation. Both male and female, FVC and $FEV_1$ had a negative correlation with WHR (male, FVC r=-0.327, $FEV_1$ r=-0.36; p<0.05; female, FVC r=-0.175, $FEV_1$ r=-0.213; p<0.05). In a multiple linear regression of considering the body composition of the total group, FVC explained FFM, BMI, and FFMI in order ($r^2$=0.579, 0.657, 0.663). $FEV_1$ was explained only fat% ($r^2$=0.011), and $FEF_{25-75}$ was explained muscle mass, FFMI, FFM ($r^2$=0.126, 0.138, 0.148). Conclusion: The BMI, fat%, muscle mass, FFM, FFMI, WHR have significant association with pulmonary function but $r^2$ (adjusted coefficient of determination) were not high enough for explaining lung function.

• The Journal of Korea Robotics Society
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• v.11 no.3
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• pp.183-192
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• 2016

Generating motion of center of mass for biped robots is a challenging issue since biped robots can easily lose balance due to limited contact area between foot and ground. In this paper, we propose force control method to generate high-speed motion of the center of mass for horizontal direction without losing balancing condition. Contact consistent multi-body dynamics of the robot is used to calculate force for horizontal direction of the center of mass considering balance. The calculated force is applied for acceleration or deceleration of the center of mass to generate high speed motion. The linear inverted pendulum model is used to estimate motion of the center of mass and the estimated motion is used to select either maximum or minimum force to stop at goal position. The proposed method is verified by experiments using 12-DOF torque controlled human sized legged robot.

• Journal of Veterinary Clinics
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• v.35 no.6
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• pp.315-318
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• 2018

A 13-year-old spayed female Beagle dog was referred with high intraocular pressure, hyperemia, and exophthalmos of the left eye and underwent ultrasound, which revealed a mass in the ciliary body of the left eye. Magnetic resonance (MR) imaging was ordered to evaluate invasion of surrounding structures and metastasis to the brain via the optic nerve. On MR imaging, a single, well-defined, smoothly marginated, triangular-to-oval-shaped mass was found. The mass was hyperintense on T1-weighted images and hypointense on T2-weighted images, similar to a previous case of ocular melanoma. The mass originated from the ciliary body and extended from the anterior chamber to the posterior chamber. Slight enhancement was observed in the mass. There was no evidence of invasion into surrounding structures or the optic nerve, and no sign of metastasis to the brain. The mass was histopathologically diagnosed as benign uveal melanocytoma.

• Journal of Physiology & Pathology in Korean Medicine
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• v.20 no.3
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• pp.697-700
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• 2006

This study was aimed at finding out changes in body composition of obese patients, such as body weight, body fat mass and lean body mass. The subjects of this study are 33 females and 6 males who are from obesity clinic at Gunsan medical center. We measured body composition using BIA(Bioelectrical Impedence Analysis) to compare pre-treatment with post-treatment. The measured data were analyzed by paired t-test using SPSS. Differences were considered significant at P<0.05. Body weigh, body fat mass and lean body mass were reduced each by $3.76{\pm}23.41{\;}kg,{\;}2.29{\pm}1.96kg{\;}and{\;}1.59{\pm}1.38kg$ at a significant level after 4 week-treatment.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.12 no.1
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• pp.15-20
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• 2005

Purpose: This study was done to compare of adult body composition and body image before and after regular exercise program at a sports center. Method: The participants were 32 adults who were beginning regular exercise at a sports center in D city. The body composition was measured by body weight, soft lean mass, fat mass, percent body fat, fat distribution, degree of obesity and BMI, using the Inbody 3.0. Body image. Data were collected using structured questionnaires and analyzed using paired t-test. Results: 1. Significant improvement was shown in body composition. 2. The score for body image increased after the program, but the change was not statistically significant. Conclusion: The short-term exercise program was very effective in improving body composition, but changes in the evaluation of body image need long-term exercise. Also, we were concluded that it is very important to consider preference level when evaluating body composition and body image.

• Korean Journal of Applied Biomechanics
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• v.22 no.1
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• pp.43-53
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• 2012

The purpose of this study was to quantitatively examine the biomechanical variables of Fouette turns for expert and beginner ballet dancers and to determine the difference in the variables between the two groups. sixteen female ballet dancers participated in this study. They were divided into an expert group(age, $25.38{\pm}1.92$ years; height, $168.38{\pm}4.66$ cm; mass, $49.63{\pm}4.41$ kg) and a beginner group(age, $20.88{\pm}1.13$ years; height, $161.63{\pm}7.42$ cm; mass, $48.88{\pm}3.64$ kg) depending on their ballet experience. Descriptive data were expressed as mean ${\pm}$ standard deviation (SD) for all variables including the duration, displacement of the center of the body, velocity of the center of the body, angle of the body segments, angular velocity of the body segments, ground reaction force, lower extremity torque, muscle activity, body weight, age, and body mass. An independence t-test was conducted to determine how the following variables differed between the beginners and experts: duration, displacement of the center of the body, velocity of the center of the body, angle of the body segments, angular velocity of the body segments, ground reaction force, lower extremity torque, and muscle activity. All comparisons were made at the p<0.05 significance level. The results show that the experts scored high on the biomechanical variables, although all the variables were not significant. Significant differences were found in the angle of body segments, angular velocity of the body segments, lower extremity torque, and muscle activity(p<0.05). The findings of this study demonstrate that the experts have the required skill to make an improved Fouette turn. The findings may also help ballet dancers to learn and understand the Fouette turn.