• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.909-913
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• 2009

수자원의 60% 이상을 지표수로부터 충당해야 하는 국내 여건 상 하천수로부터의 취수가 불가피하므로 자연하천에서의 동수역학적 흐름 해석은 지천 합류량 뿐만 아니라 취수장으로부터 유출되어 빠져나가는 취수량을 함께 고려해야 한다. 본 연구에서는 상류단 경계조건으로 입력되는 본류 유량에 생성과 소멸로 작용하는 지천유입량과 취수량을 포함하여 지천유입량 및 취수량이 하천흐름 유속분포에 미치는 영향을 살펴보기 위하여 팔당댐 직하류부터 잠실수중보 구간에 RMA-2 모형을 적용하였다. 취수장에서 빠져나가는 유량을 포함하여 모의한 경우 구의, 자양, 풍납취수장 부근에서 취수에 의한 유량 손실로 인하여 유속구조가 심하게 교란되었으며 취수를 고려하지 않은 경우에 비해 유속은 평균 25 % 낮게, 수위는 1.5 cm 높게 나타났다. 자연하천의 흐름해석 결과는 오염확산 및 하상변동을 위한 입력자료로 활용되는 경우가 많으므로 취수량을 반영한 유속구조의 해석이 필요하다.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1584-1585
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• 2011

분자의 전리(ionization)작용과 이온의 해리(dissociation)작용에 의한 유전체 내 방전해석을 위해서 전자, 양이온, 음이온의 생성과 소멸, 전자부착, 재결합 과정을 포함한 전하연속방정식, 전계에 의한 푸아송 방정식, 유전체 온도에 관한 열확산 방정식을 결합하여 해석하였다. 전계 방출 조건과 열전자 방출 조건이 경계조건으로 부여되었고 에너지 최소화 정류조건을 따르는 유한요소법(finite element method)을 이용하여 해석하였다. 비교적 작은 값을 가지는 확산성을 무시하고 대류성에 역점을 두어 발생하는 수치적 불안정은 인공확산항(artificial diffusion technique)을 도입하여 안정화하였다. 본 논문에서는 IEC standard 60897의 표준규격에 따른 2차원 축대칭 침-구 전극에 적용하여 제안된 다중물리해석기법의 타당성을 입증하였다.

• 한국전산유체공학회:학술대회논문집
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• 1999.11a
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• pp.127-138
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• 1999

In this study steady state solutions of cavity flows driven by two moving walls are studied. The north and east walls of the cavity are movable where as the remaining two walls are fixed in space. Numerical experiments for three different driving schemes for moving walls are done at two different Reynolds numbers of Re=40 and 400. The first scheme is to accelerate north and east walls simultaneously. In the second one, the north wall is started first and the east wall is accelerated later. In the third one the east wall starts first. It is usually expected that all these three cases yield the same steady state solution after sufficiently long time. However, present numerical experiments show that such a usual belief is valid only when the Reynolds number is low enough (Re=40). At higher Reynolds number (Re=400), the flow develops to three different steady states depending on the history of the boundary condition change.

• Korean Journal of Remote Sensing
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• v.28 no.1
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• pp.1-9
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• 2012

The diurnal variation in pollen vertical distributions in the atmosphere was observed by a surface-based lidar remote sensing technique. Aerosol extinction coefficient and depolarization ratio at 532 nm were obtained from lidar measurements in spring ($4^{th}$ May - $2^{nd}$ June) 2009 at Gwangju Institute of Science & Technology (GIST) located in Gwangju, Korea ($35.15^{\circ}E$, $126.53^{\circ}N$). Unusual variations of depolarization ratio were observed for six days from $4^{th}$ to $9^{th}$ May. Depolarization ratios varied from 0.08 to 0.14 were detected at the low altitude in the morning. The altitude with those high depolarization ratios was increased up to 1.5 - 2.0 km at the time interval between 12:00 and 14:00 LT and then decreased. The temporal variations in high values of depolarization ratios from lidar measurements show good agreement in patterns with the sampled pollen concentrations measured using the Burkard trap sampler. This study demonstrates that the pollen distribution data obtained by lidar measurements can be a useful tool for investigating spatial and temporal characteristic of pollen particles.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.31 no.3
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• pp.12-24
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• 2013

The cities of Joseon dynasty had weak structure against fire. Fires have resulted in damage on property and life. But they gave a chance to development various policies, planning tools, techniques and facilities for minimizing the damages of fire. This study aims to understand the progression of fire control policy in Joseon dynasty. Fire control policies can be divided into four categories ; fire prevention, prohibition of fire spreading, fire extinguishing and rescue system. The progression of fire control policies can be divided into three steps. In the first step, from Taejong to Moonjong, various policy, such as regal & administrative system, planning tools, fire control works & appliances have been built and executed. In the second step, from Danjong to Hyunjong, fire control work have taken the central place of fire control policy. In the third step, from Sookjong to Sunjong, development of fire control appliances have taken the central place of fire control policy.

• The Research Journal of the Costume Culture
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• v.23 no.5
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• pp.861-875
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• 2015

This study examines the formative characteristics of Fold architecture and how its properties are shown in the fashion of the modern work of Issey Miyake through analysis. In this research, the Fold classification criteria for analysis features that appeared in Issey Miyake fashion features were established through research literature on Fold architecture and leading research. Empirical data collection was conducted for Issey Miyake's work and collection by collecting photo materials, and design concepts and the results are analyzed in terms of features. Study ranges of Issey Miyake's creative design development are Pleats Please, A-POC, 132.5 project, and collections from 2000 to 2014. The conclusion is as follows. First, design concepts presented in the Issey Miyake fashion features of Fold are Hybrid, topology, and uncertainty. Hybrid look for the meaning of fashion, which is the interaction between the wearer and garments. The concept of topology designs clothing, focusing on interrelationship of the body and clothing, and pays no attention to absolute size or the form of the clothing. The concept of uncertainty is an uncertain form that is infinitely expandable because all the elements have openness and uncertainty due to the determined incomplete state by the creator. Second, in the results presented in the Issey Miyake fashion features is the destruction of the boundary and diagram form. The destruction of the boundary is free from traditional clothing. The diagram form is a geometric form which does not create a Dart or Princess line.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.5
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• pp.505-513
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• 2010

The tribrachial flame has attracted interest as a basic structure of the flame edge. This flame structure helps understand stabilization of laminar flames and re-ignition of turbulent flames. A number of analytical and experimental studies have been carried out on the tribrachial flame. However, the effect of the variation of the flammability limits on the structure of the tribrachial flame has not been studied in detail. In this study, the effect of non-symmetric flammability limits on the flame structure was investigated by adopting a simple numerical scheme based on several laminar flame theories. A fixed velocity field was considered and boundary matching algorithm was used on the premixed branch. The variation of the diffusion branches under the non-symmetric flammability limits and heat loss was investigated. The formation and extinction of the diffusion branch behind the premixed branch were successfully described. This basic study can help understand the fundamental structure of the flame and can form the basis of subsequent detailed studies.

• The Journal of Korean Orthopaedic Ultrasound Society
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• v.5 no.1
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• pp.1-8
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• 2012

Purpose: The purpose of this study is to report the preliminarily result of the radiologic disappearance of the calcific material, regardless of the size, type or location, on one-time ultrasonographic (US) assisted needling for calcific tendinitis of the shoulder. Materials and Methods: From March to August 2011, 46 patients (47 shoulders) with symptomatic calcific tendinitis were treated by one-time US assisted needling. Initially, a diagnostic US was performed with patient to determine the locations, numbers and sizes of calcific deposits. After 1% lidocaine local anesthesia, the calcific material was punctured with an 18-gauge needle under US monitoring. If no calcific material was aspirated after 2 or 3 additional attempts, the deposits was performed multiple puncture to achieve decompression. And then all patients were performed subacromial corticosteroid injection. All patients were followed up 4 weeks after procedure. To assess the radiologic disappearance after one-time US assisted needling, simple radiographs of the treated shoulder were performed and size, dense, and morphology of the calcific deposits were compared with those in baseline radiographs. For clinical evaluations, visual analogue scale for pain and function (PVAS and FVAS), and American Shoulder and Elbow Surgeons (ASES) score were assessed. Results: There were 11 male and 35 female patients with the mean age of 53.8 years (28-71). The morphology of the calcific deposits were 31 type A and 16 type B by French Arthroscopic Society classification and mean size was $2.9{\pm}6.7$ mm before the procedure. At 4 weeks after the index procedure, the radiographic unchanged group was included in 10 cases and changed group was 37 cases. No intergroup difference for the clinical results after the procedure was evident, but group FAS classification before the procedure was significantly different (p=0.011). Conclusion: At 4 weeks after one-time US assisted needling for calcific tendinitis of the shoulder, the radiographic size- or dense-changed cases were showed in 79%, regardless of the size, type or location of the calcific material. But the radiographic nearly or complete disappearance were showed in only 21%.

• Journal of Navigation and Port Research
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• v.34 no.6
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• pp.429-434
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• 2010

The experimental study of the hull surface roughness on a developing turbulent boundary layer which exposed to a variety of operating environments were investigated by performing particle image velocimetry(PIV) in a circulating water channel. The Reynolds number based on the width of roughness was about Re=1000. the roughness elements used were periodically arranged two-dimensionally. the flow visualization, time-mean velocity fields and vorticity fields to measure the flow characteristics were obtained. The investigation shows that the vortex generation and its progress inside the walls. And the center of the vortex was located at the middle of the height of the surface roughness.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.23 no.3
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• pp.215-224
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• 1990

Finite element model capable of solving coupled deformation-fluid diffusion equations for the fully saturated porous medium was developed using Galerkin's residual method. This model was used to study the mechanical and hydraulic behaviors of unconsolidated sediment near South Harbor, Pusan. The vertical displacement of top surface clay sediment, when subjected to the external load, is significantly affected by the excessive pore pres- sure buildup and its decay due to the pore fluid diffusion. The sand deposit overlain by the much less permeable clay layer serves as a flow channel. Consequently, the fluid diffusion due to pore pressure difference is significantly facilitated, which also affects the diffusion-dependent sediment deformation.