• Physical Therapy Korea
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• v.24 no.1
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• pp.86-96
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• 2017

Background: Scapular dyskinesis is characterized by altered scapular position and motion. Specifically, excess activation of the Upper trapezius (UT) combined with decreased Lower trapezius (LT) and Serratus anterior (SA) have been observed. The Standard push-up plus exercise (SPP) is considered as a therapeutic exercise for increasing SA activity and maintaining the scapular kinematics. In addition, Using the Sling surface can lead to higher muscle activity. However, the advantage of an unstable surface has been uncertatin. Objects: To compare the activation of the UT, LT, and lower serratus anterior (LSA) muscles during various push-up plus exercises with and without sling in subjects with scapular dyskinesis. Methods: Total 18 male subjects with scapular dyskinesis were recruited. The UT, LT, and LSA electromyographic activities and the UT/LSA and UT/LT EMG activity ratios were measured during three push-up plus exercises with and without sling. Two-way repeated of analysis of variance was used to determine the statistical significance. Results: The UT activity was significantly lower in all postures without sling than that with sling. In addition, the LSA activity was significantly greater without than with sling, and significantly large in SPP, Low back supported push-up plus (LSPP), and Quadruped push-up plus. Additionally, the UT/LSA and UT/LT activity ratios were lower in SPP and LSPP without sling than with the other four push-up plus exercises. Conclusion: The push-up plus without sling were considered to decrease UT and increase LSA activity compared with exercises with sling. Furthermore, SPP without sling seems to be a more effective exercise for increasing LSA activity and lowering the UT/LSA and UT/LT activity ratios in scapular dyskinesis subjects.

• The Research Journal of the Costume Culture
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• v.22 no.2
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• pp.290-299
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• 2014

This research sought to analyze the characteristics of breast movement at the treadmill activity levels. It also examined the effect of wearing a sports bra in reducing breast displacement. The subjects for the data collection were females in their 20s (n=2) with C-cup size breast. The experimental conditions were three different moving speeds (4 km/h, jogging: 7 km/h, and sprinting: 10 km/h) and two types of sports bras. Three dimensional breast displacement was measured. The displacement of the right nipple point was measured with a 3D motion analyzer. The results show that the breasts were greatly displaced from the walking speed (4 km/h) when subjects did not wear any bra. Whereas their breast displacement distance decreased remarkably when they wore sports bras. The nipple point moved 42~44 mm in the vertical direction at walking speed with naked condition. But it was reduced by 80% after wearing sports bras. When subjects running (7 km/h, 10 km/h) without any bra, the nipple point moved 122~141 mm. However it was reduced by 60~70% when they wore sports bras. The apartment time (time delay) between at the highest point of the upper body and the nipple was 0.25 seconds at the running speeds (7 km/h, 10 km/h) without wearing any bra. After wearing sports bras, the time delay was cut to 0.06~0.12 seconds. These results implies that without wearing any bra the skin surrounding the breasts might be seriously pulled at running activity. The functional sports bra suppress breast movement. It might prevent the sagging of breasts by preventing the damage of the Cooper's ligaments.

• Korean Journal of Applied Biomechanics
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• v.20 no.2
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• pp.239-243
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• 2010

The putting stroke accounts for 40~50% of total stroke for a golf rounding and most golfers have difficulties on the puting. Studies for the putting stroke have been conducted by analyzing various factors such as kinematics, kinetics, psychologic and physiologic parameters. A lot of devices were developed to support the studies. However there was no appropriate method to measure the position of the ball quantitatively. In this study, we developed a new measurement system to measure and evaluate the putting result. The developed system uses a USB camera to take the 2-dimensional image of the surface including the hole cup at the center of the image and the ball. The position of the ball is extracted as a set of distance and angle in polar coordinate system. We evaluated the new system with an indoor set-up for putting experiments and the system provided accurate measurement results. The proposed system can be combined with the other measurement systems such as 3D motion capture system and force plate without any restriction.

• Journal of Digital Contents Society
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• v.5 no.1
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• pp.22-27
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• 2004

To handle the high level radioactive materials such a spent fuel, the master-slave manipulaters (MSM) are wide1y used as a remote handling device in nuclear facilities such as the hot cell with sealed and shielded space. In this paper, the Digital Mockup which simulates the remote operation of the Advanced Conditioning Process(ACP) is developed. Also, the workspace and the motion of the slave manipulator, as well as, the remote operation task should be analyzed. The process equipment of ACP and Maintenance/Handling Device are drawn in 3D CAD model using IGRIP. Modeling device of manipulator is assigned with various mobile attributes such as a relative position, kinematics constraints, and a range of mobility. The 3D graphic simulator using the extermal input device of spare ball displays the movement of manipulator. To connect the exterral input device to the graphic simulator, the interface program of external input device with 6 DOF is deigned using the Low Level Tele-operation Interface(LLTI). The experimental result show that the developed simulation system gives much-improved human interface characteristics and shows satisfactory reponse characteristics in terms of synchronization speed. This should be useful for the development of work`s education system in the environment.

• The Journal of the Acoustical Society of Korea
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• v.13 no.2
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• pp.30-37
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• 1994

Since the morden targets are of high speed and getting quiet in both active and passive mode, the necessities of developing advanced SONAR system capable of performing target motion analysis (TMA) and target classification are evident. In order to develop such a system, the scattering mechanism of complex bodies needs to be, some extent, fully understood and modeled. In this paper, MOving Spread Target(MOST) signal simulation model is presented and discussed. The model is based on the highlight distribution method, and simulates pulse elongation of spread target, doppler effect due to kinematics of the target as well as SONAR platform, and distribution target strength of each highlight point (HL) with directivity. The model can be used in developing and evaluating advanced SONAR system through system simulation, and can also be used in the development of target state estimation algorithm.

• Journal of The Korean Astronomical Society
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• v.28 no.2
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• pp.139-146
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• 1995

The bright part of the halo luminosity function is derived from a sample of the 233 NLTT propermotion stars, which are selected by the 220 km/ see of cutoff velocity in transverse to rid the contamination by the disk stars and corrected for the stars omitted in the sample by the selection criterion. It is limited to the absolute magnitude range of $M_v=4-8$, but is based on the largest sample of halo stars up to now. This luminosity function provides a number density of $2.3{\cdot}10^{-5}pc^{-3}$ and a mass density of $2.3{\cdot}10^{-5}M_{o}pc^{-3}$ for 4 < $M_v$ < 8 in the solar neighborhood. These are not sufficient for disk stability. The kinematics of the sample stars are < U > = - 7 km/sec, < V > = - 228 km/sec, and < W > = -8 km/sec with (${\sigma_u},{\sigma_v},{\sigma_w}$) = (192, 84, 94) km/sec. The average metallicity of them is [Fe/H] = $- 1.7{\pm}0.8$. These are typical values for halo stars which are selected by the high cutoff velocity. We reanalyze the luminosity function for a sample of 57 LHS proper-motion stars. The newly derived luminosity function is consistent with the one derived from the NLTT halo stars, but gives a somewhat smaller number density for the absolute magnitude range covered by the LF from NLTT stars. The luminosity function based on the LHS stars seems to have a dip in the magnitude range corresponding to the Wielen Dip, but it also seems to have some fluctuations due to a small number of sample stars.

• Publications of The Korean Astronomical Society
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• v.30 no.2
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• pp.119-120
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• 2015

We report results of the measurement of the trigonometric parallax of an $H_2O$ maser source in IRAS 22555+6213 with the VLBI Exploration of Radio Astrometry (VERA). The annual parallax was determined to be $0.278{\pm}0.019$ mas, corresponding to a distance of $3.66^{+0.30}_{-0.26}kpc$. Our results confirm that IRAS 22555+6213 is located in the Perseus arm. We computed the peculiar motion of IRAS 22555+6213 to be ($U_{src}$, $V_{src}$, $W_{src}$) = ($0{\pm}1$, $-32{\pm}1$, $9{\pm}1$) $km\;s^{-1}$, where $U_{src}$, $V_{src}$, and $W_{src}$ are directed toward the Galactic center, in the direction of Galactic rotation and toward the Galactic north pole, respectively. IRAS 22555+6213, NGC7538 and Cepheus A lie along the same line of sight, and are within $2^{\circ}$ on the sky. Their parallax distances, with which we derived their absolute position in the Milky Way, show that IRAS 22555+6213 and NGC7538 are associated with the Perseus arm, while Cepheus A is located in the Local arm. We compared the kinematic distances of IRAS 22555+6213 derived with flat and non-flat rotation curve with its parallax distance and found the kinematic distance derived from the non-flat rotation assumption ($-32km\;s^{-1}$ lag) to be consistent with the parallax distance.

• Korean Journal of Applied Biomechanics
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• v.32 no.3
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• pp.87-93
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• 2022

Objective: The purpose of this research was to investigate the age-related changes in whole-body motor variability during sit-to-stand (STS) task. It has been reported that children perform motor tasks less accurately with greater variability as compared to adults. However, it is still unknown how they utilize the abundant degrees of freedom and accomplish voluntary actions. Uncontrolled manifold (UCM) analysis has been used to partition motor variabilities into two independent variability components, task-relevant variability (V_ORT) and task-irrelevant variability (V_UCM). We investigated what differences exist between children and adults with respect to these two motor variability components in relation to motor development stages. Method: Ten 6-year-old children (height: 116.2 ± 4.3 cm, weight: 23.1 ± 3.9 kg, motor development assessment percentile score: 77.5 ± 18.6%), ten 10-year-old children (height: 138.7 ± 7.2 cm, weight: 35.8 ± 10.3 kg, motor development assessment percentile score: 73.9 ± 12.7%), and ten young adults (age: 23 ± 1.6 year-old, height: 164.3 ± 11.4 cm, weight: 60.8 ± 12.0 kg) participated in this study. Each participant performed STS ten times, and a motion capture system was used to capture the whole-body kinematics. Each segment centers of mass and the whole-body center of mass were calculated, and UCM analysis was used to quantify motor variabilities, V_ORT and V_UCM. One-way ANOVA was used for statistical analysis. Results: We found that children produced more motor variabilities in V_ORT and V_UCM in all three dimensions, anterior-posterior, medial-lateral, and vertical. As age increased, both, V_ORT and V_UCM significantly decreased (p<.05). Conclusion: The greater V_ORT found in children compared to adults indicates that the repeatability over repetitions improves through development, while the greater V_UCM found in children suggests that children better utilize the abundant degrees of freedom during STS compared to adults.

• Physical Therapy Korea
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• v.30 no.2
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• pp.110-119
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• 2023

Background: Osteoarthritis is a common condition with an increasing prevalence and is a common cause of disability. Osteoarthritic pain decreases the quality of life, and simple gait training is used to alleviate it. Knee osteoarthritis limits joint motion in the sagittal and lateral directions. Although many recent studies have activated orthotic research to increase knee joint stabilization, no study has used patellar tendon straps to treat knee osteoarthritis. Objects: This study aimed to determine the effects of patellar tendon straps on kinematic, mechanical, and electromyographic activation in patients with knee osteoarthritis. Methods: Patients with knee osteoarthritis were selected. After creating the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), leg length difference, Q-angle, and thumb side flexion angle of the foot were measured. Kinematic, kinetic, and muscle activation data during walking before and after wearing the orthosis were viewed. Results: After wearing the patellar tendon straps, hip adduction from the terminal stance phase, knee flexion from the terminal swing phase, and ankle plantar flexion angle increased during the pre-swing and initial swing phases. The cadence of spatiotemporal parameters and velocity increased, and step time, stride time, and foot force duration decreased. Conclusion: Based on the results of this study, the increase in plantar flexion after strap wearing is inferred by an increase due to neurological mechanisms, and adduction at the hip joint is inferred by an increase in adduction due to increased velocity. The increase in cadence and velocity and the decrease in gait speed and foot pressure duration may be due to joint stabilization. It can be inferred that joint stabilization is increased by wearing knee straps. Thus, wearing a patellar tendon strap during gait in patients with knee osteoarthritis influences kinematic changes in the sagittal plane of the joint.

• Korean Journal of Agricultural Science
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• v.50 no.4
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• pp.941-952
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• 2023

The metabolites of agrichemicals, such as organophosphorus pesticides, are known to be more hazardous than their parent pesticides. 3,5,6-trichloro-2-pyridinol (TCP) is a major degradation product of chlorpyrifos, one of the organophosphate insecticides widely used in agriculture. In vivo or in vitro exposure to chlorpyrifos has been known to interfere with male reproductive functions, leading to reduced fertility in mammals. Therefore, this study was performed to examine the changes in the fertilization competence of boar spermatozoa exposed to TCP. Sperm samples were subjected to varying concentrations of TCP (10, 50, 100, 200 µM) and different periods of incubation. Sperm motility, motion kinematics, viability, acrosome integrity, intracellular reactive oxygen species (ROS) production, and gene expression levels (ODf2, ZPBP2, AKAP3 and AKAP4) were evaluated after exposure of the sperm to TCP. A significant dose-dependent reduction in motility was observed in sperm samples incubated with TCP compared to the controls after both incubation periods. Sperm viability was significantly decreased in samples incubated with 50, 100, and 200 µM TCP in both incubation periods. A significantly lower percentage of normal acrosomes and gene expression levels were observed in sperm samples exposed to 50, 100, and 200 µM TCP after both incubation periods, compared to the controls. There was a significant increase in the ROS production in spermatozoa incubated with 100 - 200 µM TCP after both incubation periods. Consequently, the direct exposure of boar spermatozoa to TCP interferes with sperm functions and leads to decreased fertilization. In order to identify and address the various causes of reproductive decline, the impact of chemical metabolites needs to be discussed in depth.