• Journal of the Earthquake Engineering Society of Korea
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• v.2 no.1
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• pp.63-69
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• 1998

A rotating shaft system subjected to seismic motions has been investigated for the various operating modes at start-up. During an earthquake excitation, the rotor may hit the stator of machines due to the excessive deformation of shaft, and thus the response of rotating shaft system of which foundation is supported by the vibration isolation devices has been simulated. In order to examine the transient response of the rotating shaft system at the start-up to both the various operating conditions and the seismic excitation simultaneously, nonlinear equations of motion are derived and solved numerically using Runge-Kutta method. The response of the rotating shaft system is calculated according to the operating modes as recommended by the machine and the system parameters such as the spring stiffness of isolation devices.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.28 no.1
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• pp.1-7
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• 2022

Purpose: The purpose of this study is to examine the unstable wall squat exercise and stable bridge exercise on posture in normal adults. Methods: The subjects of this study were 34 university students who were normal health adults, equally and randomly allocated to a unstable wall squat exercise group (male 7, female 10), an experimental group, and a stable bridge exercise group, a control group. Both did so for 30 minutes three times per week over a six-weeks period. Using Back Mapper, their trunk inclination (TIN), trunk imbalance (TIM), pelvic position (PPO), pelvic torsion (PTO), pelvic rotation (PRO) and the position of their scapula (PSA) were evaluated. Results: When the pre-test and post-test results of experimental group and control group were compared, statistically significant differences in TIN, PTO and PSA of experimental group were seen. Conclusion: Unstable wall squat exercise accompanied by abdominal drawing-in may be applied as a method to correct the posture in normal adults.

• Clinics in Shoulder and Elbow
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• v.12 no.1
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• pp.67-75
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• 2009

Purpose: This study evaluated the clinical outcomes of debridement arthroplasty using the posteromedial approach in elbow joints with pain and bony limitation of motion. Materials and Methods: This study involved 16 elbows in 16 patients with pain and bony limitation of motion, which were treated by debridement arthroplasty using the posteromedial approach from March 2005 to March 2008. The mean follow up period was 27.6 (13~52) months. The clinical outcomes were analyzed using the Visual Analogue Scale(VAS) for pain scale, the preoperative and postoperative range of motion and the Mayo Elbow Performance Scores(MEPS). Results: The VAS was decreased significantly from a preoperative mean of 4.5 to a postoperative mean 1.1 (p<0.001). The average arc of motion improved significantly from $61.6 (0~90)^{\circ}$ preoperatively to $109.4 (80-120)^{\circ}$ postoperatively (p<0.001). The MEPS also improved significantly from 59.4 to 85.6 postoperatively (p<0.001). There were no complications, such as hematoma and elbow instability. Conclusion: Debridement arthroplasty using the posteromedial approach is a useful surgical procedure in the elbow joint with pain and bony limitation of motion, where all compartments can be debrided, the ulnar nerve can be manipulated easily and damage to the medial collateral ligament can be minimized.

• Clinics in Shoulder and Elbow
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• v.12 no.2
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• pp.189-198
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• 2009

Purpose: We wanted to evaluate the clinical results of the Latarjet procedure for treating anterior shoulder instability combined with a glenoid bone defect. Materials and Methods: Between Oct. 2006 and May. 2007, fourteen patients underwent a Latarjet operation to treat their anterior shoulder instability combined with a glenoid bone defect. The mean follow-up period was 15 months (range: 12 to 19 months), and the average age at the time of surgery was 29.9-years-old (range: 19 to 44 years). There were 13 males and 1 female. Eight patients exhibited involvement of the right shoulder. The dominant arm was involved in 8 patients. Six patients had undergone a previous arthroscopic Bankart repair before their Latarjet operation and 2 patients had a history of seizure. Results: The average Rowe score improved from 51.8 to 80.2 with 9 excellent, 4 good, and 1 fair results. The average Korean shoulder score for instability improved from 61.6 to 82.1 postoperatively. The active forward flexion and external rotation at the side of the involved shoulder was an average of $8^{\circ}$ and $16^{\circ}$ less than that of the uninvolved shoulder. The muscle strength of the involved shoulder measured 78.7% in forward flexion and 82.5% in external rotation, as compared with that of the uninvolved shoulder. There was 1 case of dislocation, 1 transient subluxation, 2 fibrotic unions, 1 resorption of the transferred coracoid process, 1 intraoperative broken bone, 1 transient musculocutaneous nerve injury and 1 case of stiffness. Conclusion: The Latarjet procedure for treating anterior shoulder instability combined with a significant glenoid defect effectively restores function and stability through extending the articular arc at the expense of external rotation. We should be cautious to avoid or detect complications when performing coracoid transfer.

• The Journal of Korean Orthopaedic Ultrasound Society
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• v.1 no.2
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• pp.73-77
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• 2008

Purpose: The purpose of this study was to describe the method of dynamic sonographic measurements in the evaluation of the MCL injury of the knee joint while applying valgus and varus stress. Materials and Methods: Seven cases of MCL injury from January to April of 2008 was used for the study. For the evaluation of the medial instability, sonography was used immediately after injury, 6 weeks and 12 weeks after conservative treatment with limited motion brace. The length between the foot of the medial femoral epicondyle and the most proximal point of the tibial cortex was measured in 30 degrees flexion with valgus and varus stress of the knee joint. Results: The foot of the medial epicondyle and the starting point of the proximal tibial cortex underneath the round portion of the articular cartilage were always able to be seen on ultrasonography, even in varus and valgus stress with gravity in 30 degrees flexion of the knee joint. The results of measurements were always constant. Conclusion: Sonography can be used in evaluation of medial instability under the dynamic valgus and varus stress of the knee joint without further injury.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.3
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• pp.276-282
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• 2016

This study examined the effects of 8-weeks hip muscle training on the hip joint abductor muscle isokinetic strength and foot pressure distribution in elite players with chronic ankle instability (N=19). A total of 19 subjects had chronic ankle instability from at least 2 ankle sprains, and were given 8-weeks hip muscle training exercise. The hip muscle strength of the elite players with chronic ankle instability increased significantly, but the foot pressure distribution and ratio of the foot pressure distribution of the elite players with chronic ankle instability did not reach statistical significance and the ratio of the foot pressure distribution showed a similar trend. These results suggest that the strength and foot pressure distribution of the affected-side might increase to that of the unaffected-side. The 8-weeks hip muscle training helped improve the chronic ankle instability of the elite players. Therefore, the hip muscle strength and foot pressure distribution are the primary factors of a rehabilitation program on ankle sprains.

• Journal of Nutrition and Health
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• v.50 no.6
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• pp.603-614
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• 2017

Purpose: This study was performed to identify the health and nutritional status of Korean adults according to food security by age group. Methods: The subjects were 20~79 year old adults (n = 16,595) who participated in the fifth Korea National Health and Nutrition Examination Survey (2010~2012). Subjects were divided into three groups based on food security such as secure, mildly insecure, and moderately/severely insecure groups. Dietary intake was estimated by 24-hour dietary recall. As for mental health status, the data on mental stress, sleep hours, depression symptoms, and suicide ideation were used. Results: Korean adults who were exposed to high food insecurity typically had low income levels, lived alone, and were recipients of basic welfare. In the 20~39y group, people with higher food insecurity had lower concentrations of hemoglobin and higher iron-binding capacity. In the 40~59y group, people with higher food insecurity had lower HDL-cholesterol. In the 60~79y group, people with higher food insecurity had higher total cholesterol levels, more stress, more experiences of depression symptoms, and were more suicidal. Mean intakes of energy, protein, calcium, phosphorus, potassium, vitamin A, carotene, vitamin $B_1$, vitamin $B_2$, niacin, and vitamin C were lower in the food insecure groups. Amounts of vegetables, fruits, and seasoning intakes tended to be lower in people with higher food insecurity. The effects of food security on nutrition intake were greater in the 40~59y and 60~79y groups than the 20-39y group. Conclusion: Food insecurity was related to certain health indicators such as anemia and cholesterol levels and affected mental health. The effects of food insecurity on health and nutritional status were different by age group.

• Journal of the Korea Society of Computer and Information
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• v.27 no.1
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• pp.97-105
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• 2022

The purpose of this study was to analyze the effects of flossing band exercise on the range of motion and vertical jump for taekwondo demonstration athletes with ankle functional instability. The subjects of this study were 21 male Taekwondo Demonstration Team athletes enrolled at D University. They were divided into functional ankle instability group(FAIG, n=7), mild ankle instability group(MAIG, n=7), and ankle stability group(ASG, n=7). All groups performed a acute flossing band exercise program. The results of this study are as follows; dorsi flexion(p<.01), inversion(p<.01), eversion(p<.05) and vertical jump(p<.01) were significantly increased in the FAIG. Flossing band exercise of Taekwondo demonstration team with FAI increased joint range of motion and vertical jump. Therefore, it was confirmed that it could be an intervention that can improve performance and reduce the risk of ankle injury.

• Journal of Dental Rehabilitation and Applied Science
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• v.17 no.3
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• pp.189-193
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• 2001

교합조정은 비가역적인 술식이므로 예방적인 목적으로 사용하는 것은 바람직하지 않으며 환자가 증상을 호소하거나 환자의 구강검사시 교합간섭으로 인한 증상이 확인된 경우라도 자연치에서의 교합조정술은 반드시 신중을 기해야 한다. 교합조정술을 시행하기 전에 먼저 하악의 위치가 안정되어야 한다는 것을 명심하고 이를 위해 치과의사는 하악의 중심위에 대한 이해와 중심위로의 하악유도 방법에 대한 숙지도 필요하다. 또한 심한 악관절 장애나 통증 및 불안정한 하악의 위치를 보이는 경우 구강내 교합상이나 교합 안정장치가 선행되어야 하는 경우가 있다. 교합조정술을 시행해야 하는 치과의사 자신이 교합조정술에 대한 지식을 충분히 습득하고 있어야 하며, 교합조정술의 적응증을 분명하게 확인한 뒤 조심스럽고 정확하게 시술을 시행해야 한다. 즉, 잘못된 교합조정으로 오히려 교합간섭을 야기할 수도 있음을 명심해야 한다. 그러나 교합조정에 대해 올바로 이해하고 일반적인 교합조정의 원칙을 지켜 정확히 시행한다면 교합조정은 결코 환자에게 해를 주지 않고, 자유로운 하악운동을 가능케 하며, 교합의 안정성을 유지해 줄 것이다.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2007.04a
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• pp.349-352
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• 2007

본 논문은 계층적 공정 경쟁 유전자 알고리즘(Hierarchical Fair Competition-based Genetic Algorithms : HFCGAs)을 이용한 회전형 역 진자 시스템의 최적 2-자유도 제어기 설계를 제안한다. 비선형이며 불안정한 운동을 하는 회전형 역 진자 시스템은 회전지렛대(rotating arm) 위의 폴(pole)이 적당한 제어력이 없는 상황에서 중력에 의해 어느 한 쪽 방향으로 넘어지려고 할 때, 외부에서 회전지렛대에 힘을 가하여 회전지렛대의 특정위치와 폴의 각도를 유지시키는 시스템으로, 본 논문에서는 두 개의 피드백 제어루프를 갖는 2-자유도 제어기를 구성한다. 각각의 제어기는 PD 제어기로 구성하고, 조기수렴 문제를 내재하고 있는 기존의 유전자 알고리즘의 해결방안중 하나인 HFCGAs를 이용하여 최적의 제어기 파라미터들을 구한다. 마지막으로 실제 공정에 적용하여 설계된 제어기의 성능을 평가한다.