• 대한의용생체공학회:의공학회지
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• 제25권5호
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• pp.377-382
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• 2004

본 연구에서는 건강한 남성 13명을 대상으로 최대자발 근수축의44%, 55%, 66%에 해당하는 40, 50, 60kg의 부하를 주었으며 초당 48$^{\circ}$의 속도로 요추신전 운동을 반복함으로써 근피로를 유발 시켰으며, 피검자의 왼쪽 척추기립근에 표면전극을 부착하여 근전도 신호를 측정하였다. 웨이브렛을 이용하여 '시-주파수'영역에서 근전도 신호를 주파수대역별로 분리하여 근피로도를 측정하고 중앙주파수를 이용하여 얻은 결과를 비교하였다. 본 연구에서는 중앙주파수가 시간에 따라 더 맞은 주파수 영역으로 천이되며 단지 대표 주파수의 경향만 나타냄을 확인할 수 없었다. 그러나 웨이브렛을 이용한 근피로도 분석 방법은 중앙주파수와는 달리 근육의 피로함에 따라 고주파수 대역의 신호(375～438Hz)는 일정하거나 감소하고 저주파영역의 신호(0∼125Ha)는 증가하는 경향이 확인되어 웨이브렛 분석을 통해서 근피로를 정량화할 수 있음을 알 수 있었다. 본 연구를 통해 동 적운동 시 웨이브렛을 이용한 분석방법이 중앙주파수 보다 근피로도를 분석하는데 있어 더욱 유용함을 확인할 수 있었다.확인할 수 있었다.

• 농업과학연구
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• 제47권3호
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• pp.533-544
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• 2020

In this paper, we conducted a dynamic ex-post assessment on the grape business cessation support System. Based on the analysis results, in the short term, there was an increase in grape price due to a decrease in production and accompanying increases in the prices of consumption substitution items. However, in the long run, grape prices fell again due to an increase in grape production because of the entry of new grape farmers and the growth of adult grape trees. In addition, the analysis showed that the balloon effect caused by the conversion of crops caused indirect damage such as an increase in the production volume of substitution crops and a decrease in prices. When analyzing the social welfare measurement, the results showed that the support system for business cessation increased the overall social welfare due to an increase in producer welfare because of a price increase in the short term, but in the long term, both producer and consumer welfare decreased. In the end, it is necessary to review the system because the government's intervention may cause market distortion and inefficient resource allocation. Above all, it is necessary to minimize the indirect effect of the industry's contraction and balloon effect due to excessive business cessation. For this, conditional support should be provided in parallel with post management rather than unconditional support. In addition, it is necessary to provide a strategic support system that considers substitution items in addition to those items to be supported.

• The Journal of Korean Physical Therapy
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• 제33권5호
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• pp.238-244
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• 2021

Purpose: Menstruation is associated with menstrual symptoms like pain and balance problems which have an impact on the quality of life. Pilates increases pelvic stability and reduces menstrual pain by inducing abdominal muscle contraction. This study was done to evaluate the effects of Pilates on menstrual pain, symptoms, balance, and quality of life when compared to aerobic exercise. Methods: Thirty-nine women with menstrual pain were randomly divided into the Pilates group (n=13), aerobics group (n=13), and control group (n=13). The Pilates group performed lumbar-pelvic stabilization exercises, while the aerobic group ran on a treadmill. The control group did not undergo any intervention. The experimental groups exercised for four weeks (12 sessions) and did not exercise during menstruation. The Y-balance test was performed on the second day of menstruation to evaluate dynamic balance. The questionnaires administered immediately after menstruation were the visual analog scale (VAS), Korea Oswestry Disability Index (ODI), and the modified Menstrual Distress Questionnaire (MDQ). The paired t-test was used to compare the effect of exercise within the three groups and a oneway analysis of variance was used to compare between groups. Results: VAS and MEDI-Q scores significantly decreased in the Pilates group after 4 weeks compared with those in the aerobic and control groups. Moreover, ODI and Y-balance scores increased in the Pilates group compared with those in the aerobic and control groups (p<0.05). Conclusion: The Pilates stabilization exercises are effective and help in improving menstrual pain, balance and other menstrual symptoms assessed through ODI, and MEDI-Q, compared to aerobic exercises.

• 한국해양공학회지
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• 제32권6호
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• pp.419-426
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• 2018

Recently, in an effort to reduce the energy efficiency design index (EEDI), studies on energy saving devices (ESDs) have been conducted. In this study, we designed a post-device suitable for a KRISO container ship (KCS) using computational fluid dynamics (CFD). In order to increase the efficiency of the post-device, a twisted rudder was used, which has a proven performance (showing a 1.34% reduction in DHP compared to the bare hull at 24 knots) in previous research at Pusan National University. In addition, an increase in efficiency was expected by the use of a rudder bulb, including the discontinuous section of the twisted rudder and a divergent propeller cap to prevent the contraction of the wake. The optimization criterion was the case where the delivery power was the least compared with the bare hull. We analyzed the cause of the efficiency increase through an analysis of the self-propulsion factor. The case study for optimization was divided into 4 types (1. clearance of the bulb and cap, 2. shape of the bulb, 3. size of the bulb and cap, and 4. asymmetric bulb). Finally, with a clearance of 50 mm from the ship, a spherical bulb with the cap having an angle of $5^{\circ}$, and an asymmetric rudder bulb with a bulb diameter of 1.2HH/1.4H (horizontal/vertical) showed a 2.05% reduction in DHP compared to the bare hull at 24 knots. We will fabricate a post-device that will be optimized in the future and verify the performance of the post-device through model tests.

• 대한물리치료과학회지
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• 제26권1호
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• pp.54-60
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• 2019

Background: This study hypothesized that increased muscle activity and balancing ability of the gluteus maximus during toe-tap exercise. Design: Cross sectional Study. Methods: After hearing the explanation of the experiment, the subjects performed a Star excursion balance test and measured the Maximum Voluntary Isomeric Contraction (MVIC). After toe-tap exercise, the MVIC was measured again and the Star excursion balance test was measured. Results: There was no significant difference in activity of gluteus muscle before and after the toe-tap exercise. There was a significant difference in the balance ability in the lateral, posterolateral, and posterior sides of the non-superior foot, but there was no significant difference in the anterior, anterolateral, posteromedial, medial, and anteromedial sides. In the case of superior foot, there were significant differences in six directions, with the exception of anterolateral and lateral sides. Conclusion: The pelvic stabilizing "gluteus maximus" exercises for balance, which is currently on the table, has many high-level exercises that are hard to do unless you're an athlete. But the Toe-tap exercise is also possible for the elderly and weak women.

• 한국정보통신학회논문지
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• 제23권12호
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• pp.1720-1725
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• 2019

본 논문에서는 불연속 네트워크(discontiguous network)의 라우팅 축약기능(summary) 알고리즘에 대한 방식의 효율화에 대해 고찰을 한다. 서로 다른 전체의 서브넷 정보를 업데이트하여 전송하는 것보다 네트워크 정보를 축약하여 축약된 업데이트 정보만 전송하면 라우팅 테이블의 축약으로 라우터의 자원의 효율화가 이루어 지며 네트워크 안정과 성능을 향상시킬 수 있다. 그러나 네트워크 설계과정에서 불연속적인 네트워크가 구성될 경우 네트워크 축약 기능으로 문제가 발생되며 근본적인 라우터의 효율화의 결과를 가져오지 못한다. 본 논문에서 제안하는 알고리즘은 자동 축약 알고리즘의 단점을 보완한 알고리즘으로, 이로 인해 라우팅 테이블의 안정성을 높이고 그 결과 네트워크 장비의 CPU Utilization을 기존 16.5%에서 6.5%까지 낮추어 효율화가 구현됨을 확인하였다.

• The Journal of Korean Physical Therapy
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• 제34권1호
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• pp.12-17
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• 2022

Purpose: Ankle dorsiflexion is an essential element of normal functions, including walking, activities of daily living and sport activities. The tibialis anterior (TA) muscle functioned as a dorsiflexor and as a dynamic stabilizer of the ankle joint during walking and jumping. This study aimed to compare TA muscle thickness using ultrasonography according to the four different toe and ankle postures for the selective TA strengthening exercise. Methods: This study were recruited 26 (males: 15, females: 11) aged 20-30 years, with no injury ankle and calf in the medical history, had normal dorsiflexion and inversion range of motion (ROM). The thickness of the TA muscle was measured by ultrasonography in the four different toe and ankle postures: 1. Ankle dorsiflexion with all toe extension and ankle inversion (ITEDF); 2. Ankle dorsiflexion with all toe flexion and ankle inversion (ITFDF); 3. Ankle dorsiflexion with all toe extension and neutral position (NTEDF); 4. Ankle dorsiflexion with all toe flexion and neutral position (NTFDF). One-way repeated analysis of variance (ANOVA) and Bonferroni correction were used to confirm the significant difference among conditions. The level of statistical significance was set at α=0.01. Results: TA muscle thickness with ITFDF was significantly greater than in any other ankle positions, including ITEDF, NTFDF, and NTEDF (p<0.01). Conclusion: Among the four toe and ankle postures, isometric contraction in ITFDF postures showed the greatest increase in thickness of TA rather than ITEDF, NTEDF, and NTFDF postures. Based on these results, ITFDF can be recommended in an efficient way to selectively strengthen TA muscle.

• The Journal of Korean Physical Therapy
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• 제36권2호
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• pp.71-77
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• 2024

Purpose: The prolonged use of digital devices has led to the widespread adoption of poor postures, particularly rounded shoulder posture (RSP), associated with shoulder impingement and pain. This study investigates the effects of neuromuscular electrical stimulation (NMES) on RSP in healthy adults. Methods: Thirty adults with RSP were randomly assigned to NMES only, exercise only, or NMES with exercise groups. NMES was applied to the lower trapezius, which was the target muscle in this study, for a total of 2 weeks, 5 times per week, 20 minutes per session. The exercise program included pectoralis minor stretching, wall-slide exercise, dynamic hug exercise with band, and Brugger stretching for upper body with band, which were performed for a total of 2 weeks, 5 times per week, 20 minutes per session. Outcome measures, including the Supine Method (SM) for posture and surface electromyography (EMG) of the lower trapezius for muscle activity, were assessed before the intervention, after 5 sessions, and after 10 sessions. Results: All the groups showed significant changes in the SM and % maximal voluntary isometric contraction (%MVIC) over time (p<0.05). The NMES group had significantly reduced SM at 1 week, while the exercise and combined groups had reduced SM at 2 weeks (p<0.017). All the groups had increased %MVIC at 2 weeks (p<0.017), with no significant differences observed between groups. Conclusion: NMES alone can be as effective as exercise in improving RSP. NMES combined with exercise also showed positive outcomes, thus offering diverse treatment options for this condition.

• 한국터널지하공간학회 논문집
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• 제20권1호
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• pp.39-53
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• 2018

일반적으로 터널 내 총환기저항계수는 입출구 손실계수, 벽면마찰계수 그리고 급격한 확대나 축소단면 등에 의해 발생하는 부차적 손실계수의 총합으로 구성된다. 개통 전 터널의 경우는 가동 중인 환기팬을 중단하게 되면, 터널 내 풍속은 총환기저항력에 의해 감소하는 현상이 나타난다. 즉, 속도감쇄법은 개통 전 터널에서 비교적 안정적이면서도 손쉽게 터널 내 벽면마찰계수를 추정하는 방법이다. 그러나 기존의 선행연구에서 환기팬의 가동을 중단 후 수렴되는 풍속이 음수일 경우는 속도감쇄법에 따른 벽면마찰계수의 추정이 곤란한 특성이 있다. 반면 교통환기력이 작용하는 공용 중인 터널에서는 좀더 복잡한 과정을 거치지만, 합리적인 벽면마찰계수를 추정할 수 있다. 본 연구에서는 교통환기력의 측정변수를 최소화할 수 있는 방법을 제안하였고, 공용 중 터널에 적용할 수 있는 방법을 고찰하였다. 또한 환기팬 정지 후 터널 내 풍속이 감소하는 동안에 외부 자연풍의 급격한 변화가 발생하여도 교통환기력이 일정할 경우에 대하여, 교통환기력의 증분을 계산할 수 있는 방법과 터널 내 벽면마찰계수를 추정할 수 있도록 동적 시뮬레이션이 가능한 프로그램 로직을 개발하였다.

• 한국전문물리치료학회지
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• 제11권4호
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• pp.19-29
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• 2004

Many muscles of the trunk and hip are capable of contributing to the stabilization and protection of the lumbar spine. To have optimal effectiveness, a training program should include dynamic back/stomach/hip exercises. This study was designed to assess the L5 level paraspinal, external abdominal oblique, and gluteus maximus muscle activities during various low back stabilization exercises. Participants were 26 healthy adults (13 males, 13 Females), aged 21 to 28 years. The surface electromyography (EMG) was recorded from the L5 level paraspinal, external abdominal oblique, and gluteus maximus muscles. The recorded signal was averaged and normalized to the maximal electromyographic amplitude obtained during the maximal voluntary contraction. The measurements were taken during 3 low back stabilization exercises. One-way analysis of variance with repeated measures was used to examine the difference, and a post hoc test was performed with least significant difference. A level of significance was set at p<.05. The significance of difference between men and women, and between the electromyographic recording sites was evaluated by an independent t-test. The EMG activity for the externus oblique and gluteus maximus muscles had significant differences among 3 exercises (p<.05). In males, the EMG activity for the external abdominal oblique muscle had significantly increased differences during exercises 1 and exercise 2 (p<.05). The gluteus maximus muscle had significantly increased differences during exercise 2 and exercise 3 (p<.05). In females, the multifidus muscle had significantly increased difference during exercise 3 (p<.05), the external abdominal oblique muscle had significantly increased difference during exercise 1 (p<.05). and the gluteus maximus muscle had significantly decreased difference during exercise 3 (p<.05). The results were that the external abdominal oblique muscle was apparently activated during the curl-up exercise in females and males, and the multifidus muscle was apparently activated during the bridging exercise in females and during the sling exercise in males and females.1)In comparison of the %MVC between males and females, exercise 2 and exercise 3 apparently activated of the multifidus and gluteus maximus muscles in both males and females (p<.05). The EMG activity of the gluteus maximus muscle of the males significantly increased during exercise 2 and exercise 3 (p<.05). The EMG activity the multifidus muscle of the females was significantly increased during exercise 2 and exercise 3 (p<.05). More research is needed to understand the nature of motor control problems in the deep muscles in patients with low back pain.