• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.6
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• pp.683-693
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• 2010

In this paper, we propose a new parallel mechanism for the legs of biped robots and the control of the robot's locomotion. A leg consists of two 3-DOF parallel platforms linked serially: one is an orientation platform for a thigh and the other is the 3-DOF asymmetric parallel platform for the shank. The desired locomotion trajectory is generated on the basis of the Gravity-Compensated Inverted Pendulum Mode (GCIPM) in the sagittal direction and the Linear Inverted Pendulum Mode (LIPM) in the lateral direction, respectively. In order to simulate the ground reaction force, a 6-DOF elastic pad model is used underneath each of the soles. The performance and effectiveness of the proposed parallel mechanism and locomotion control are shown by the results of computer simulations of a 12-DOF parallel biped robot using $SimMechanics^{(R)}$.

• IE interfaces
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• v.18 no.3
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• pp.288-296
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• 2005

Many jobs and activities in our daily lives require squatting postures. The fore part includes housekeepers, farmers, and welders and the latter includes a wide variety of activities such as housekeeping; planting, cultivating and harvesting various agricultural products; grinding, welding, etc. It is speculated that prolonged squatting postures without any supporting stool would gradually cause musculoskeletal injuries to workers. This study is conducted to examine the proper height of stools according to the position of the working materials and to develop wearable stools for workers with squatting posture. Forty male and female subjects participated in the experiment to find the proper height of stools according to the position of the working materials. Subjects were asked to squat and work with 3 different working positions: floor level; ankle level; shank level of 3 different stool height conditions: 10cm height; 15cm height; and 20cm height. After 5 minutes of maintaining a squatting work posture while sitting on the different height stools, Likert summated rating method as well as pairwise ranking test was applied to evaluate the user preferences for provided stools under the conditions of different working positions. The results of statistical analysis show that the subjects preferred 10cm height stool for floor level, 15cm height stool for ankle level, 20cm height stool for knee level. We thus strongly recommend to use appropriate height stools in accordance with the different working positions. Moreover, a prototype wearable stool was designed such that workers with squatting posture do not need to move the stool while they are moving about. The purpose of developing wearable stool was to decrease the physical stress and hence promote worker's health who work with squatting posture.

• Korean Journal of Applied Biomechanics
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• v.16 no.1
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• pp.139-149
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• 2006

This study is to analyze the kinematic variables of inward $1{\frac{1}{2}}$ somersault in platform diver. For the manner, 3 people form the national diving team in the year 2000were chosen as the subjects and two S-VHS video cameras set in 60frames/sec were used for recording their motions. Coordinated raw positions data through digitizing are smoothing by butter-worth's low-pass filterin method at a cut off frequency 6.0Hz. and the direct linear transformation(DLT) method was employed to obtain 3-D position coordinates. The conclusions were as follows. However, horizontal distance which is the change of the COG, form the point of the jump to the point of Event 3 where the player is out of the board range completely, Subject B showed 105.1cm and 71.1cm of the vertical distance which are shorter horizontal distance and higher vertical distance, thus, took a great advantage of the position to prepare for the entry. Therefore, if a player takes higher position by speeding up the vertical velocity at the moment of the jumping off the board, and stays in the air longer, the player can have more time to show his skill. Because of the use of the characteristics of the inward somersault, keeping the safe distance form the board is important but in order to higher the completeness, it is ideal to keep the horizontal distance little over 100cm. Also, the angles of shoulder and elbow from Event 1 to 4, depending on swing of the arms, motions in the air, getting ready for the entry, showed some difference individual by individual, according to the velocity of the thigh and shank showed much difference while getting ready and take-off, and it's because of the individual's different bending and straightening for horizontal and vertical distance.

• Physical Therapy Korea
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• v.3 no.1
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• pp.1-11
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• 1996

The purpose of this study was to analyse the subtalar joint movement characteristics in human stance phase. The data of subtalar joint movement patterns are collected by CTA(calcaneus to tibia angle) measurements. CTA is defined as a angle formed between the bisect of the posterior shank and bisect of the posterior heel, as determined by placement of the retroreflective markers. The angle measured in degrees. The participants are 74 healthy individuals (37 men and 37 women) who have no orthopedic and neurological impairment, aged from 19 to 29 years(mean 22.95). Prior to participation, each subjecct informed the procedures of experiment from researcher and assistant researcher. The equipments of this study are walking grid, marking tapes, goniometer, video camera, monitor and ink for foot print are used in the study. In order to determine the statistical significance of result, the paired t-test and Pearson correlation were applied at the 0.05 level of significance. The results were as follows : 1. The reliability of measured CTA value are showed a high correlation, ranged from .86 - .94. 2. The mean value of step width are 7.67cm in men and 6cm in women. So, significant difference between men and women in 0.05 level of significance. 3. There was significant difference between man and women's TOA(toe out angle)(p<0.05). 4. The CTA of female's is more higher than male's one, however not statistical difference between man and women(p>0.05). 5. The CTA is reduced according to increasing TOA(p<0.05).

• Journal of Korean Society of Steel Construction
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• v.10 no.4 s.37
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• pp.749-758
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• 1998

The evaluation of shear stiffness of shear connection in composite bridges with CIP concrete deck is analysed. Shear stiffness of shear connection in full-depth precast concrete deck bridges is obtained from experiments. 3-dimensional finite element analyses of push-out specimen are carried out to investigate the effects of characteristics of filling material strength in shear connection on shear stiffness and local stress distribution. The load-slip relations obtained from the analyses are compared with those of experiments. The equation of initial shear stiffness of shear connection in precast concrete deck bridge is proposed. Linear analyses are performed to evaluate the effects of the shank diameter of shear connector and the strength of mortar on the characteristics of deterioration and failure load obtained by the failure criterions of each material. The failure loads are estimated and compared with test results.

• Journal of the Korean Society of Clothing and Textiles
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• v.23 no.1
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• pp.3-13
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• 1999

This study was performed for purpose of getting fundamental information requisite to wear velvet clothes that is more comfortable for the human body and also the environment. It was carried out in a human wearing test and thermal manikin test at the same time in a controlled-condition chamber. The experimental environment had a ambient temperature of 15$\pm$0.5$^{\circ}C$ with the relative humidity at 5$^{\circ}C$$\pm$5% and with air velocity at less that than 0.2m/sec. Velvet differ from common plain weaves in thermal properties because it's constructed in two parts one is ground part and the other part is pile part. In order to investigate the thermal resistance of velvet eight different combination of 4 velvet kinds and 2 lings kinds as experimental clothes. [(4 velvet kinds : Acetate cuprammoium Rayon Cotton Wool) (2 lining kinds : acetate viscose rayon)longrightarrow8 combination: Aa, Av, Ra, Rv, Ca, Cv, Wa, Wv: the simplified character] The results of this study can be summarized as follows : 1. For the regional thermal resistance the differences in eight clothes as well as differences in each part were significant. As a whole the breast part showed the highest thermal resistance and the leg part was higher than the shank part. The rank of the total thermal resistance was put at Wa>Wv>Ca>Cv>Aa>Av>Ra>Rv in this order. 2. Considered clothing microclimate microclimate temperature has a similar tendency to the total thermal resistance. It showed a significance in the differences of eight clothes and each parts. the belly part was highest in every combination. On the other hand for clothing humidity there was a significance between back and breast part only in the human wearing test. 3. It was indicated that CLO value was highly positively correlated with the clothings' weight and showed a high negative correlation with the air permeability.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.8
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• pp.62-69
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• 2010

Internal lathe machining with a boring bar is weak with respect to vibration because the bar is long and slender. Therefore, it is important to study the dynamic characteristics of a boring bar. The purpose of this study was to identify the effects of overhang and cutting conditions on the dynamic response characteristics of a boring bar. For an efficient experiment, an $L_g(3^3)$ orthogonal array was applied and the results were quantitatively analyzed by ANOVA. Overhang, feed per revolution, and depth of cut were selected as independent variables. Meanwhile, dynamic stiffness, damping ratio, damping coefficient, and acceleration were chosen as dependent variables. The vibration signal was obtained from an accelerometer attached to the boring bar, followed by visualization by a signal analyzer. The effect of overhang was found to have a significant effect on the dynamic stiffness, damping ratio, and damping coefficient, but the other variables did not. As the length of the overhang increased, the dynamic stiffness decreased and the damping ratio increased. In addition, the damping coefficient increased until the length of the overhang was 4D (where D is the shank diameter), after which it remained constant. The acceleration decreased until the overhang length was 4D, and then increased sharply when the overhang was increased further. From these results, the behavioral trend of the damping characteristics changed when its overhang length was 4D. Consequently, there is a critical point that the dynamic characteristics of boring bar change.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.6
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• pp.767-777
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• 2014

Characterizing local chicken types and their mostly rural production systems is prerequisite for designing and implementing development and conservation programs. This study evaluated the management practices of small-scale chicken keepers and the phenotypic and production traits of their chickens in Oman, where conservation programs for local livestock breeds have currently started. Free-range scavenging was the dominant production system, and logistic regression analysis showed that socio-economic factors such as training in poultry keeping, household income, income from farming and gender of chicken owners influenced feeding, housing, and health care practices (p<0.05). A large variation in plumage and shank colors, comb types and other phenotypic traits within and between Omani chicken populations were observed. Male and female body weight differed (p<0.05), being $1.3{\pm}0.65$ kg and $1.1{\pm}0.86$ kg respectively. Flock size averaged $22{\pm}7.7$ birds per household with 4.8 hens per cock. Clutch size was $12.3{\pm}2.85$ and annual production $64.5{\pm}2.85$ eggs per hen. Egg hatchability averaged $88{\pm}6.0%$ and annual chicken mortality across all age and sex categories was $16{\pm}1.4%$. The strong involvement of women in chicken keeping makes them key stakeholders in future development and conservation programs, but the latter should be preceded by a comprehensive study of the genetic diversity of the Omani chicken populations.

• Korean Journal of Applied Biomechanics
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• v.19 no.3
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• pp.603-610
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• 2009

The purpose of this study was to determine how spandex pants affect impact force and muscle activities in the lower extremity. Seven pairs of surface electrodes were attached to the right-hand side of the body. Paired t-test was performed to test if significant difference exist between two conditions(p< .05). The average IEMG activities in the TA, BF, and GM during the landing phase reduced significantly with spandex pants compared to regular pants. All peak IEMG activities except the RF in wearing spandex pants group were significantly greater than the corresponding values in wearing regular pants one. The greater muscle activity recorded in wearing spandex pants can be attributed to the greater motor unit recruitment needed to decelerate and stabilized their bodies. Impact force and loading rate were not significantly decreased with wearing spandex pants. Since the spandex pants used in this study were not custom-fit based on girth of each participants thigh and shank, compression and elasticity for the pants could not be optimized.

• Journal of the Korean Dietetic Association
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• v.16 no.3
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• pp.270-278
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• 2010

We examined whether visual perception related to consumption norms could influence food consumption and satiety by using modified soup bowls with elevated bottoms. Twenty-six healthy women (BMI 19.9 $kg/m^2$ Age 24 yr) participated in the study once a week for 2 weeks. The subjects were served beef shank soup in one of two soup bowls (180 g soup in the modified bowl or 250 g soup in the normal bowl). The results showed that subjects who ate from the modified soup bowl consumed less soup (135.3 kcal vs 180.0 kcal, P<0.001) and had lower total energy intake (390.6 kcal vs 438.1 kcal, P<0.01) than those who ate from the normal soup bowl. However, despite consuming fewer calories, satiety levels of those who ate from the modifed soup bowl were not significantly different from those using the normal soup bowl. In conclusion, these results indicate that the modified soup bowl which created a distorted visual perception ot the amount of soup in the bowl leads to decreased soup intake and total energy intake without altering satiety. The reduced amount of soup in the modified soup bowl may also implicitly suggest what might be interpreted as an appropriate amount to consume, and also in essence suggest reduced consumption norm.