• ETRI Journal
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• v.36 no.3
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• pp.396-406
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• 2014

We have designed and investigated a new congestion control scheme, called optimal and fully explicit (OFEX) controller. Different from existing relatively explicit controllers, this new scheme can provide not only optimal bandwidth allocation but also a fully explicit congestion signal to sources. It uses the congestion signal from the most congested link instead of the cumulative signal from the flow path. In this way, it overcomes the drawback of relatively explicit controllers exhibiting bias toward multi-bottlenecked users and significantly improves their convergence speed and source throughput performance. Furthermore, our OFEX-controller design considers a dynamic model by proposing a remedial measure against the unpredictable bandwidth changes in contention-based multi-access networks. Compared with former works/controllers, this remedy also effectively reduces the instantaneous queue size in a router and thus significantly improves queuing delay and packet loss performance. We have evaluated the effectiveness of the OFEX controller in OPNET. The experimental comparison with the existing relatively explicit controllers verifies the superiority of our new scheme.

• Journal of computational fluids engineering
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• v.4 no.3
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• pp.44-51
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• 1999

A modified version of SST turbulence model is suggested to simulate unsteady separated flows over oscillating airfoils. The original SST model, which shows good performance in predicting various steady flows, often results in oscillatory behavior of aerodynamic loads in large separated flow regions. It is shown that this oscillatory behavior is due to the adoption of the absolute value of vorticity in generalizing the original model. As a remedy, a modification is made such that the vorticity in the original SST model is replaced by strain rate. The present model is verified for a mild separated airfoil flow at fixed angle of incidence and for unsteady flowfields about oscillating airfoils. The results are compared with BSL model and original SST model. It is illustrated that the present model gives a better agreement with the experimental results than other two models.

• The Mathematical Education
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• v.44 no.4 s.111
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• pp.525-534
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• 2005

The purpose of this study is to analyze difficulties in the density word problem solving process of seventh graders and to search for the way to increase their problem solving ability in the density word problem. The results of this study could help teachers diagnose students' difficulties involved in density word problem and remedy the understanding of the concept of density, algebraic expressions, and algebraic symbols.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.22 no.1
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• pp.32-43
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• 2014

Worldwide, air transport demand of this century is expanding rapidly, and each countries' demand is also increasing. Thus a number of low-cost carriers emerged in existing air transportation business sector and airman qualification check work regarding aviation safety management is increasing too. As the remedy for the result of aviation safety audit by ICAO and FAA in 2001 that governmental activity for aviation safety had been performed by a small number of aviation safety inspectors, airman qualification inspection system implemented by airlines was improved and the government has established the system that authorized airman qualification inspectors check airmen qualification with airlines according to the international trend. This study suggests the need of improvement of airman qualification inspection system that existing inspection system as the means of safety management can be transferred to Operations Safety Inspection(OSI) activity which is compliant with international standards.

• Journal of Physiology & Pathology in Korean Medicine
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• v.25 no.5
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• pp.773-776
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• 2011

This study was focused on a certain clinical symptom, which could applicated by Pyeongwi-san, and the radical treatment. Pyeongwi-san is applicable to dampness retention in the spleen and stomach, accompanied by abdominal fullness, anorexia, nausea and regurgitation. Main action of Pyeongwi-san is to dry dampness, invigorate the spleen, promote the flow of gi, and regulate the stomach. The herbal remedy drying dampness like Pyeongwi-san however, is just indicatio symptomatica therefore radical treatment must be used together. Jeunginmaegchi, a medical book written by Gyeong-Myeong Jin, who was lived in Myeong dynasty. This book contains many clinical applicable symptoms and constituents derived from Pyeongwi-san. The herbal prescriptions composing Pyeongwi-san is composed of Changchul, Hubak, Jinpi, Gamcho. The major action of these herbs is drying dampness. Therefore, it shoud be seriously consider that curative therapy must eliminate the cause of endogenous dampness.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.502-504
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• 2003

The main objective of this study is to examine the effectiveness of newly available high spatial resolution satellite images, in evaluating vegetation environment of the urban areas. In doing so, we have used satellite images from QuickBird and selected some areas of Fukuoka City, Kyushu Japan, as study area. The results of the study revealed that, high resolution images are more effective in close monitoring of the vegetation status and green plants should be planted in open spaces and roofs of urban areas to increase vegetation, which will in turn act as a remedy to reduce heat island phenomenon.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.108-111
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• 2005

The Communication Ocean, Meteorological Satellite (COMS) as the one of the national space program has been developed by Korea Aerospace Research Institute (KARl). The Geostationary Ocean Color Imager (GOCI) is one of the main payloads ofCOMS which will provide consistent monitoring of ocean-colour around the Korean Peninsula from geostationary platforms. The ocean color observation from geostationary platform is required to remedy the coverage constraints imposed by polar orbiting platforms. In this paper the main characteristics of GOCI are described and compared with the current ocean color sensors. The GOCI will provide the measurement data of 6 visible channels and 2 nearinfrared channels (40Onm - 900nm). The high radiometric sensitivity is essential of ocean color sensor because of the weak water leaving radiance.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.12
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• pp.1045-1052
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• 2000

In this paper, we propose a method to apply the Input Shaping Technique (IST) to multi-input multi-output (MIMO) systems. In MIMO systems, there is a high possibility of multi-mode residual vibration. The IST filter designed for this multi mode may need a longer time to suppress the residual vibration. Previous works prove that we can shorten the time lag by using negative sequence. This negative sequence, however, causes another problem - it requires excessive control input. In this paper, we provide a remedy to reduce the size of control input by limiting the reference input by limiting the reference input and its derivative. The result of simulations and experiments on a 2 link flexible arm confirmed the effectiveness of the proposed method.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1636-1637
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• 2011

본 논문에서는 전자파를 이용한 하지정맥류 치료를 위하여 균일한 온도 분포를 갖는 도파관 안테나를 제안하였다. 제안된 안테나는 일반 도파관 안테나보다 균일한 전계 분포를 가지므로 보다 균일하고 넓은 온도 분포를 갖는다. 제안된 안테나는 도파관 개구부에 파장의 1/4 길이의 철사를 설치하여 전계가 가운데로 몰리지 않도록 설계하였다. 정맥류 치료를 위해, 제안된 안테나를 이용하여 인체와 비슷한 돼지 피부에 적용하여 실험하였고, 이를 통해 보다 균일하게 피부의 온도를 올릴 수 있다는 것을 확인하였다.

• Korean Journal of Pharmacognosy
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• v.32 no.1 s.124
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• pp.1-5
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• 2001

The Chinese crude drug, 'Yong Dam (龍膽)' which is derived from the root of Gentiana plants of the family Gentianaceae, has been used as remedy for stomachic, intestinal catarrh, convulsion, etc. With regard to the botanical origin of 'Yong Dam', it has been considered to be Gentiana species of Gentianaceae, especially Gentiana scabra, but there has no pharmacognostical confirmation on it. To clarify the botanical origin of 'Yong Dam' from Korea, we studied on the anatomical characteristics of Gentiana species growing wild in Korea i.e. Gentiana scabra var. buergeri, G. uchiyamai, G. triflora, G. axillariflora var. coreana and of 'Yong Dam' from Korea on Korean market. Through our studies, the botanical origin of 'Yong Dam' from Korea was proved to be Gentiana scabra var. buergeri and Gentiana axillariflora var. coreana.