• Journal of the Korean Society of Physical Medicine
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• v.4 no.3
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• pp.175-182
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• 2009

Purpose：The purpose of this study is to investigate the effects of Taekwondo training causing leg-muscular strength for elementary school children. Methods：The subjects were Taekwondo group (n=20) and non-Taekwondo group (n=20) from 5-6 graders of elementary school. The Tkd group exercised Taekwondo and the non-Taekwondo group exercised free gymnastics. The subjects were measured 3 times(pre, mid and after)during the 8weeks program. The leg muscular strength peak torque and average power were measured. And the extension-flection of angular speed 60 deg/sec and 180 deg/sec was measured. Results：The results of this study can be summarized as follows: 1. Compared with the Tkd group, the non-Tkd group showed no significant difference in tests statistically in case of right-left of pre-4weeks. The leg muscle's peak torque did not show significant difference in the extension angular 60 deg/sec(p>.05). 2. The score of flection angular speed 60deg/sec was not different in tests leg strength of right-left to pre-4weeks(p<.05), but the muscle was increased according to the amount of time spent in case of the 4-8weeks. 3. Compared with the Tkd group, the non-Tkd group showed no significant difference in tests statistically in case of right-left of pre-4weeks. The leg muscle's peak torque did not show significant difference in the extension angular 180deg/sec(p>.05). The right leg muscular strength was increased in case of the 4-8weeks. The left leg showed no difference. 4. Leg muscular strength was increased in the case of the pre-4weeks in the right of flection angular speed 180deg/sec. The left did not show difference. The right leg muscle in case of the 4-8weeks showed no difference. The left showed significant difference. Conclusion：Taekwondo training is effective for leg-muscular strengthing for elementary school children.

• Journal of Power Electronics
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• v.14 no.5
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• pp.1069-1078
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• 2014

This study presents the design and implementation of a web-based remote laboratory for a multi-mode single-leg power converter, which is a topic in advanced power electronics course. The proposed laboratory includes an experimental test rig with a multi-mode single-leg power converter and its driver circuits, a measurement board, a control platform, and a LabVIEW-based user interface program that is operated in the server computer. Given that the proposed web-based remote laboratory is based on client/server architecture, the experimental test rig can be controlled by a client computer with Internet connection and a standard web browser. Although the multi-mode single-leg power converter can work at four different modes (main boost, buck-boost, boost-boost, and battery boost modes), only the buck-boost mode is used in the experiment because of page limit. Users can choose the control structure, control parameters, and reference values, as well as obtain graphical results from the user interface software. Consequently, the feedbacks received from students who conducted remote laboratory studies indicate that the proposed laboratory is a useful tool for both remote and traditional education.

• Korean Journal of Poultry Science
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• v.33 no.1
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• pp.7-14
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• 2006

The effects of aerobic and vacuum packaging of fresh duck meat on meat qualities including color, cooking loss, shear force, lipid oxidation and fatty acid composition during cold storage were investigated. The result showed that pH of the samples were decreased as increasing storage time, and leg meat showed significantly (p<0.05) higher than breast meat. Redness showed significantly (p<0.05) higher value in breast meat compared to leg meat as increasing the storage time. However, TBARS value showed significantly (p<0.05) higher in breast meat compared to leg meat as increasing storage time. This result suggested that the lower pH affected lipid oxidation and discoloration of the meat samples. However, fatty acid composition of 1 day storage time showed that aerobic packaging of leg meat had lower (p<0.05) ratio of palmitic acid and higher (p<0.05) ratio of linoliec acid, whereas vacuum packaging of leg meat showed higher (p<0.05) ratio of palmitic acid at 7 days storage time than other treatments. Therefore, this data speculated that saturated fatty acid like palmitic acid and unsaturated fatty acid like linoleic acid were affected by lipid oxidation at different storage time. Finally, aerobic packaging meat accelerated lipid oxidation compared to vacuum packaging meat, hence self life was no longer better than vacuum packaging meat without relation of different type of meat from duck.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.12
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• pp.1193-1200
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• 2015

An effective swing trajectory of legged robots is different from the swing trajectories of humans or animals because of different dynamic characteristics. Therefore, it is important to find optimal parameters through experiments. This paper proposes a real-time nonlinear programming (RTNLP) method for optimization of the swing trajectory of the legged robot. For parameterization of the trajectory, the swing trajectory is approximated to parabolic and cubic spline curves. The robotic leg is position-controlled by a high-gain controller, and a cost function is selected such that the sum of the motor inputs and tracking errors at each joint is minimized. A simplified dynamic model is used to simulate the dynamics of a robotic leg. The purpose of the simulation is to find the feasibility of the optimization problem before an actual experiment occurs. Finally, an experiment is carried out on a real robotic leg with two degrees of freedom. For both the simulation and the experiment, the design variables converge to a feasible point, reducing the cost value.

• Journal of Power Electronics
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• v.14 no.6
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• pp.1178-1188
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• 2014

This study proposes a finite-state model predictive controller to regulate the load current and balance the DC-link capacitor voltages of a four-leg neutral-point-clamped converter. The discrete-time model of the converter, DC-link, inductive filter, and load is used to predict the future behavior of the load currents and the DC-link capacitor voltages for all possible switching states. The switching state that minimizes the cost function is selected and directly applied to the converter. The cost function is defined to minimize the error between the predicted load currents and their references, as well as to balance the DC-link capacitor voltages. Moreover, the current regulation performance is improved by using a two-step prediction horizon. The feasibility of the proposed predictive control scheme for different references and loads is verified through real-time implementation on the basis of dSPACEDS1103.

• The Journal of Korean Physical Therapy
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• v.29 no.3
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• pp.135-141
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• 2017

Purpose: This study was to identify the anticipatory postural adjustment (APA) mechanism which is represented by the onset time of trunk muscles and the displacement of the center of pressure (COP) according to the different base of support (BOS) during upper extremity movement. Methods: Thirty healthy subjects (14 males, 16 females) participated in this study. The movement was performed for 10 trials during each of various BOS (shoulder - width double leg stance, narrow base double leg stance, tandem stance, non-dominant single leg stance) at the 1.2 Hz frequency. Electromyography was used to measure muscle onset time and biorescue was used to measure characteristics of the displacement of COP. Surface bipolar electrodes were applied over the right deltoid anterior, right latissimus dorsi, both rectus abdominis, both internal oblique and both erector spinae. The data were analyzed by repeated one-way ANOVA and Duncan's post hoc test. Results: The study has revealed following. There were significant differences with muscle onset time in each BOS (p<0.01). There were significant differences in characteristics of the COP in each BOS (p<0.01). Conclusion: The study found that the more narrowed the basis requires the more rapid anticipatory postural control in contralateral postural muscle when the upper extremity movement is performed.

• Journal of The Korean Society of Integrative Medicine
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• v.7 no.3
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• pp.61-69
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• 2019

Purpose : The purpose of this study was to investigate the effects of Straight leg lifts (SLL) and double leg lowering (DLL) exercise on abdominal muscle activity, visual analog scale (VAS), and flexibility in patients with chronic low back pain (LBP). Methods : A total of 30 LBP patients were divided into two groups: those with SLL exercise group 15 (male=8, female=7) and those with DLL exercise group 15 (male=7, female=8). Before the intervention, the abdominal muscle activity, VAS, and flexibility were measured. After 4 weeks of intervention, the above variables were measured in the same way. The SLL exercise bends the leg $45^{\circ}$ in the supine position, and the DLL exercise was performed as opposed to SLL. At this time, the pressure biofeedback unit (PBU) was placed behind the lumbar to reduce the instability of the pelvis and muscles. The subjects were instructed to use the PBU to maintain the target pressure determined (40 mmHg) during the exercise. Results : The external oblique (EO), internal oblique (IO), and transverse abdominis (TrA) were significantly different in the SLL and DLL group, and EO, IO, and TrA activity improved more significantly increased in the DLL than SLL group (p<.05). The results on the VAS and flexibility were significantly different both group (p<.05). However, there was no significant difference between the groups (p>.05). Conclusion : SLL and DLL exercises in patients with LBP were able to confirm the increased activity of the abdominal muscles, decreased pain, and increased flexibility of the waist. In addition, DLL exercise is more effective in patients with LBP in terms of muscle activity.

• Animal Bioscience
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• v.37 no.2
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• pp.315-322
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• 2024

Objective: The aim of this study was to evaluate the effect of pre-slaughter fasting time on carcass yield, meat quality, blood parameters and glucose metabolism in broilers. Methods: Four hundred and fifty Arbor Acres (AA) broilers at 42 days of age were divided into 5 groups with 6 replicates in each group and 15 chickens as one replicate. Following this period, broilers from each group were distributed among five groups according to preslaughter fasting period as 4, 8, 12, 16, or 20 h. Results: With increasing fasting time, the carcass yield (p<0.01), the breast muscles yield (p<0.01) and the thigh yield (p<0.01) of the broilers were all linearly increased. With increasing fasting time, the L^* values (p<0.01), cooking loss (p = 0.020), moisture content (p<0.01) in the leg muscles linearly downregulated, while the drip loss (p = 0.043), pH_{45 min} (p<0.01) and pH_{24 h} (p<0.01) were linearly upregulated. A trend for a lower (p = 0.071) shear force in the leg muscles was also observed in broilers fasted for longer time. Similar results were also found in breast muscles. The different fasting treatments did not influence the breast muscles glycogen content (p>0.10), while the increase of fasting time resulted in a linear decrease of the blood glucose (p = 0.021) and, more specifically, the glycogen content of the liver and leg muscles (p<0.001). With increasing fasting time, the aspartate transaminase (p<0.01), uric acid (p<0.01), and triglycerides (p<0.01) in serum linearly downregulated, while the alanine aminotransferase was linearly upregulated. Conclusion: The results of this study show a significant influence of fasting time on carcass yield and meat quality in broilers. Moderate fasting (8 to 12 h) before slaughter can reduce the weight loss of broilers. Prolonged fasting (≥16 h) increased body weight loss, decreased slaughtering performance and fluctuating blood indexes of broilers.

• Archives of Plastic Surgery
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• v.36 no.5
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• pp.583-590
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• 2009

Purpose: In the cases of a vascular compromised condition in an injured lower extremity, soft tissue coverage with free tissue transfer presents a challenging problem to the reconstructive surgeon. For this reason, cross - leg flaps are still used in unusual circumstances. Advances in surgical technique has made the cross - leg free flap possible although it may require long operation time along with significant donor site morbidity. Therefore, a pedicled cross - leg muscle flap may be an alternative treatment modality when local flap or free flap is not possible. Methods: Twelve patients(9 males and 3 females) underwent the operation between October of 2001 and December of 2008. The patients' age ranged from 6 to 82 years. The unusual defects included the regions such as the knee, popliteal fossa, distal third of the tibia, dorsal foot, and the heel. Indications for the cross - leg gastrocnemius flap are inadequate recipient vessels for free flap(in eight cases), extensive soft tissue injuries(in three cases) and free flap failure(in one case). The muscle flap was elevated from contralateral leg and transferred to the soft tissue defect on the lower leg while both legs were immobilized with two connected external fixator systems. Delay procedure was performed 2 weeks postoperatively, and detachment was done after the establishment of the adequate circulation. The average period from the initial flap surgery to detachment was 32 days (3 to 6 weeks). Mean follow - up period was 4 years. Results: Stable coverage was achieved in all twelve patients without any flap complications. Donor site had minimal scarring without any functional and cosmetic problems. No severe complications such as deep vein thrombosis or flap necrosis were noted although mild to moderate contracture of the knee and ankle joint developed due to external fixation requiring 3 to 4 weeks of physical treatment. All patients were able to walk without crutches 3 months postoperatively. Conclusion: Although pedicled cross - leg flaps may not substitute free flap surgery, it may be an alternative method of treatment when free flap is not feasible. Using this modification of the gastrocnemius flap we managed to close successfully soft tissue defects in twelve patients without using free tissue transfers.

• Journal of the Korean Society for Marine Environment & Energy
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• v.17 no.3
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• pp.174-181
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• 2014

Design procedure of LEG(Linear Electric Generator) is introduced by performing the time-domain analysis for the heaving motion of a floating buoy coupled with LEG. A vertical truncated buoy is selected as a point absorber and a double-sided Halbach array mover and cored slotless stator is adopted as a linear electric generator. LEG with a double-sided Halbach array mover and cored slotless stator is designed with the input data such as the heave motion velocity and wave exciting forces in time-domain. The validity of designed LEG is confirmed by performing generating-characteristic-analysis under the sinusoidal motion of a buoy, based on the numerical techniques such as FE(Finite Element) analysis. In particular, an ECM(Equivalent Circuit Method) is employed as the design tool for the prediction of generating characteristics under irregular wave conditions. Finally, we confirm that the ECM gives reasonable and fast results without sacrifice of accuracy.