• 한국컴퓨터산업학회논문지
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• 제7권1호
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• pp.23-32
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• 2006

컴퓨터와 네트워크를 활용한 사이버 강좌는 언제 어디서나 학습할 수 있고 빠른 피드백, 역동적인 학습형태를 이루어 낼 수 있는 장점이 있어 활발한 연구가 진행되고 있다. 그러나 대부분의 연구들은 사이버 대학의 운영 현황의 문제점, 사례연구, 활성화 연구에 초점을 두고 있어 학습의 주체자인 학습자들에 대한 요구사항을 반영한 연구는 미비한 상태이다. <중략> 설문 분석 결과, 이들이 선호하는 콘텐츠 유형은 텍스트+이미지+동영상이라는 것을 알 수 있었으며 불만 사항으로는 학습난이도, 강의분량, 시스템접속, 출석 등이 있는 것으로 분석되었다. 이러한 불만 요소를 제거하기 위해 개선 방안을 수립하여 이를 새로운 사이버 강좌에 반영한 후 학업 성취도를 검증한 결과 전체 평균 17.3점이 향상되어 매우 높은 학업 성취도를 보여주었다. 이러한 성취도결과는 교수자의 관점에서 교수설계도 중요하지만 학습자의 관점에서도 교수 설계도 필요하다는 것을 의미한다.

• Journal of Nutrition and Health
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• 제37권8호
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• pp.645-654
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• 2004

This study examined the effect of excess calcium (Ca) on the iron (Fe) bioavailability and bone growth of marginally Fe deficient animals. Two groups of weanling female SD rats were fed either normal Fe (35 ppm) or Fe deficient diet (8 ppm) for 3 weeks. Then each group of animals were assigned randomly to one of three groups and were fed one of six experimental diets additionally for 4 weeks, containing normal (35 ppm) or low (15 ppm) Fe and one of three levels of Ca as normal (0.5%), high (1.0%), or excess (1.5%). Feces and urine were collected during the last 3 days of treatment. After sacrifice blood, organs, and femur bone were collected for analysis. Final body weight and average food intake were not affected by either the levels of dietary Ca or Fe. Low Fe diet significantly reduced the level of serum ferritin, however, for Hb, Hct, and TIBC no difference was shown than those in the normal Fe group. TIBC increased slightly by high and excess Ca intake in low Fe groups. For both normal and low Fe groups, high and excess Ca intakes reduced the apparent absorption of Fe and Fe contents of liver significantly (p < 0.05). Calcium contents in kidney and Femur of rats that were fed high and excess levels of Ca were significantly greater than those of normal Ca groups. However, weight, length, and breaking force of the bone were not affected by increased Ca intakes. Both in control and low Fe groups, high and excess intakes of Ca decreased the apparent absorption of Ca. These results indicate that the excess intakes of calcium than the normal needs would be undesirable for Fe bioavailability and that the adverse effects be more serious in marginally iron deficient growing animals. In addition bone growth and strength would not be favorably affected by high Ca intakes, though, the long term effect of increased Ca contents in bone requires further examination.

• 한국항공우주학회지
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• 제48권11호
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• pp.903-910
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• 2020

본 논문은 AESA 레이다를 탑재한 항공기가 비행 중 발생하는 바람과 진동에 의해 받는 영향을 평가하기 위한 시뮬레이터를 소개한다. AESA 레이다는 항공기의 노즈콘(nose cone)에 탑재하며, 비행 시 공기의 저항력에 의한 진동이 발생한다. 이 진동은 AESA 레이다의 거동에 영향을 주며, 수신한 신호의 위상 오차를 야기할 수 있다. 시뮬레이터는 레이다의 위치와 자세를 정확하게 모의하기 위해 강체 동역학, 평균 바람/난류, 그리고 모드/환경 진동에 대한 수학적 모델과 노즈콘에 대한 기하모델을 고려한다. 일련의 테스트 시나리오에 기반한 연구가 개발된 시뮬레이터의 효율성을 입증하기 위해 수행되었다.

• KSBB Journal
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• 제25권1호
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• pp.85-90
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• 2010

An ion selective microelectrode (ISME) was fabricated to measure concentrations of ammonium (${NH_4}^+$-N) and nitrate (${NO_3}^-$-N) according to the depth of nitrifying biofilm. The limits of detectability and validity of results were investigated to evaluate the ISME. The electromotive force (EMF) was directly proportional to the ion concentration, and average detection limits of ${NH_4}^+$ and ${NO_3}^-$ ISME were $10^{-5.14}$ and $10^{-5.18}$ M, respectively. The concentrations of ${NH_4}^+ $-N and ${NO_3}^-$-N in various depths on the nitrifying biofilm were measured by the ISME. When a modified Ludzack-Ettinger (MLE) process was operated at an HRT of 6 h, concentration gradients of ${NH_4}^+$-N in the bulk solution and biofilm at depths of $100\;{\mu}m$ decreased by $70\;{\mu}M$, while ${NO_3}^-$-N increased by $101\;{\mu}M$ and remained constant thereafter. At an HRT of 4 h, concentration gradients of ${NH_4}^+$-N at depths of $500\;{\mu}m$ decreased by $160\;{\mu}M$ and ${NO_3}^-$-N increased by $162;{\mu}M$ and remained constant thereafter. As HRT decreased, the concentration gradients of ${NH_4}^+$-N and ${NO_3}^-$-N between bulk solution and biofilm was higher due to the increase of nitrogen load. Also, the concentration gradients of the ${NH_4}^+$-N and ${NO_3}^-$-N of biofilm in the second aerobic tank were lower than those of the first aerobic tank, suggesting differences of nitrogen load and concentrations of DO between the first and second aerobic tank.

• 대한족부족관절학회지
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• 제17권1호
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• pp.34-39
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• 2013

Purpose: To evaluate the effectiveness of intraoperative stress test for diagnosis of occult Lisfranc injury. Materials and Methods: Between April 2009 and October 2012, 21 patients with occult Lisfranc injuries underwent intraoperative stress test and internal fixation. There were 11 males and 10 females with an average age of 45.3 years (range, 23~79 years). Injuries were caused by traffic accident in 10 cases, indirect force (twisting injury) in 8 cases, and crush in 2 cases, falling from a height in 1 case. Unstable injuries on stress radiograph in occult injury of Lisfranc joint were treated by open reduction or closed reduction and fixation with cannulated screw or K-wire. Radiological evaluation was assessed according to preoperative and postoperative diastasis between $1^{st}$ and $2^{nd}$ metatarsal base. Results: Assoicated injuries were 9 cases of metatarsal fractures, 6 cases of cuneiform fractures and 6 cases of both metatarsal and cuneiform fractures. Medial and middle column fixation was in 13 cases, and three columns fixation was in 8 cases. Initial diastasis between $1^{st}$ and $2^{nd}$ metatarsal base was 2.8 mm (1.3~4.7 mm) on AP radiograph and postoperative diastasis between $1^{st}$ and $2^{nd}$ metatarsal base was 1.2 mm (0.5~2.4 mm) on AP radiograph. Conclusion: Even there is no sign of clear Lisfranc injury, it is necessary to pay attention and give evaluation on circumstances of occult Lisfranc injuries with metatarsal or cuneiform fractures. Intraoperative stress test is helpful to diagnose an occult Lisfranc injury. For unstable injuries on stress radiographs of occult Lisfranc joint injury, operative treatment with open or closed reduction and internal fixation is useful method.

• Archives of Plastic Surgery
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• 제36권1호
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• pp.118-121
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• 2009

Purpose: Constricted ear, which is named by Tanzer includes lop ear, cup ear, and sort of prominent ear. It has classified three groups by Tanzer, especially grou I and IIA have been corrected by banner flap, Musgrave's technique, tumbling concha - cartilage flap, reversed banner flap and others. However, these techniques were too invasive for correcting mild degree of deformity. Therefore, we corrected the ear with mattress suture which is simple and less invasive. Method: The operations were done against 5 patients from 2005 March to 2008 April. All the cases were unilateral ears with constriction included helix and scaphoid fossa without difference in length between both ears. Though a posterior auricular skin incision, the folded cartilage is exposed and two parallel incisions on superior crus were made. After mattress suturing in cartilage, the superior crus of antihelix was formed and its force enables the folded portion to be in a normal anatomic position. Result: All of 5 patients got satisfactory results. There were no complications like hematoma or skin necrosis, and no recurrence during follow - up period(the average period was 9 months). And we couldn't recognize the difference between height of both auricles. Conclusion: Mattress suture is simple, less invasive, and suitable on correcting mild deformity of constricted ear with better result, so here we suggest the method.

• Archives of Plastic Surgery
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• 제41권4호
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• pp.325-329
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• 2014

Background Liposuction is a procedure to reduce the volume of subcutaneous fat by physical force. Intracellular storage fat is composed of triglyceride, whereas circulating fat particles exist as cholesterol or triglycerol bound to carrier proteins. It is unavoidable that the storage form of fat particles enters the circulation system after these particles are physiologically destroyed. To date, however, no studies have clarified the fatal characteristics of fat embolism that occurs after the subclinical phase of free fat particles. Methods A mixture of human lipoaspirate and normal saline (1:100, 0.2 mL) was injected into the external jugular vein of rats, weighing 200 g on average. Biopsy specimens of the lung and kidney were examined at 12-hour intervals until postoperative 72 hours. The deposit location and transport of the injected free fat particles were confirmed histologically by an Oil Red O stain. Results Inconsistent with previous reports, free fat particles were transported from the intravascular space to the parenchyma. At 24 hours after infusion, free fat particles deposited in the vascular lumen were confirmed on the Oil Red O stain. At 72 hours after infusion, free fat particles were accumulated compactly within the parenchymal space near the perivascular area. Conclusions Many surgeons are aware of the fatal results and undiscovered pathophysiologic mechanisms of free fat particles. Our results indicate that free fat particles, the storage form of fat that has been degraded through a physiological process, might be removed through a direct transport mechanism and phagocytotic uptake.

• 한국운동역학회지
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• 제22권1호
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• pp.17-24
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• 2012

This study is for providing fundamental data of sport biomechanics in GRF & plantar pressure of stepping foot of skilled & unskilled players' at the soccer instep shooting moments. Wearing Pedar-x of Novel, the study has drawn the following conclusion after measuring and analyzing the impact on the GRF and plantar pressure of stepping foot at the instep shooting moments. First, maximum vertical GRF showed higher in the skilled group than in the unskilled group. The results showed significantly different. This study reached the conclusion that the players in the skilled group performed faster and stronger stepping foot motions that the ones in the unskilled(p<.01). Second, since the plantar pressure of the skilled group appeared significantly higher than that of the unskilled, it has brought us to the conclusion that the skilled group performed faster and stronger stepping foot motions than the unskilled group (p<.05). Third, at the moment of instep kicking, the skilled group's average maximum plantar foot pressure of stepping foot was higher than the unskilled. Though the difference was not statistically significant, it can be concluded that the skilled group performed faster and stronger stepping foot motions than the unskilled group(p>.05). Fourth, for the COP moving route of stepping foot while instep kicking, the skilled people performed accurate and strong shooting motions directly toward the target direction with stable postures, no matter how it's left, right, front or back.

• 생명과학회지
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• 제18권12호
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• pp.1775-1778
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• 2008

본 연구는 태권도 전문 기능화 개발을 위한 제안으로서 고급기술의 사용과 기능을 고려하여 회전력이 강화된 전문태권도화의 운동역학적인 특징을 분석하고자 하였다. 연구방법은 2가지 태권도화 종류를 이용하여, 텐션마찰계수 측정계와 지면반력기를 이용하여 얻은 결론은 다름과 같다. 정적마찰계수 비교는 A사 0.60, M사 0.61로 나타났다. 모멘트(회전 마찰력) 비교는 M사 태권도화가 회내(3.23Nm), 회외(2.70Nm) 모두 A사 태권도화 회내(3.20Nm), 회외(2.62Nm) 보다 높게 나타났다. 지면반력 비교는 Fz의 값은 세가지 조건에서 각각 유의한 차이가 있는 것으로 나타났으며(p<0.05), Fy의 최고의 힘은 세가지 조건에서 유의한 차이가 없는 것으로 나타났다. Fx 보다 앞서 나타나는 피크의 형태를 보여주고 있다.

• Earthquakes and Structures
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• 제19권4호
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• pp.303-313
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• 2020

Spacious experimental and numerical investigation has been conducted by researchers to increase the ductility and energy dissipation of concentrically braced frames. One of the most widely used strategies for increasing ductility and energy dissiption, is the use of energy-absorbing systems. In this regard, the cyclic behavior of a chevron bracing frame system equipped with multi-pipe dampers (CBF-MPD) was investigated through finite element method. The purpose of this study was to evaluate and improve the behavior of the CBF using MPDs. Three-dimensional models of the chevron brace frame were developed via nonlinear finite element method using ABAQUS software. Finite element models included the chevron brace frame and the chevron brace frame equipped with multi-pipe dampers. The chevron brace frame model was selected as the base model for comparing and evaluating the effects of multi-tube dampers. Finite element models were then analyzed under cyclic loading and nonlinear static methods. Validation of the results of the finite element method was performed against the test results. In parametric studies, the influence of the diameter parameter to the thickness (D/t) ratio of the pipe dampers was investigated. The results indicated that the shear capacity of the pipe damper has a significant influence on determining the bracing behavior. Also, the results show that the corresponding displacement with the maximum force in the CBF-MPD compared to the CBF, increased by an average of 2.72 equal. Also, the proper choice for the dimensions of the pipe dampers increased the ductility and energy absorption of the chevron brace frame.