• Journal of the Society of Naval Architects of Korea
• /
• v.31 no.3
• /
• pp.100-111
• /
• 1994

This study was carried out for understanding the characteristics of the spray around high speed vessels. Prismatic planing hull made of an acrylate board was used to the tests. The distribution of local spray velocity were estimated from the analysis of the spray visualization. A new test system for measuring the spray thickness is proposed, and was used to estimate the local spray thickness in the model. The pressure distributions on the bottom of the hull are measured and integrated to estimate the pressure drag of the model in the towing tests. Finally. the spray drag/lift component is separated from the total drag/lift on the prismatic hull. These test results show that the spray drag component on high speed vessels is relatively large and important in total drag.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2023.05a
• /
• pp.131-131
• /
• 2023

지하수는 담수-염수 경계면의 형성 및 변동 특성, 지하수위 분포 및 변동특성에 따라 기저지하수, 준기저지하수, 상위지하수 등으로 구분된다. 이 중, 기저지하수는 담수(1,000g/cm³)와 염수(1,025g/cm³)의 비중 차이에 의해 담수가 염수 상부에 Ghyben-Herzberg 원리에 의해 부존한다. 본 연구에서는 부존 형태에 따른 지하수위 변동을 보고자 하였다. 먼저 이상화된 지형에서 부존형태에 따른 지하수위 변동의 영향을 확인하고자, OpenGeoSys 모형을 이용하여 3차원 수치모의를 수행하였다. 그 결과 상위지하수의 지하수위보다 기저지하수 조건에서의 지하수위가 낮아진 것을 확인할 수 있었다. 이는 부존 형태의 차이로 인해 발생되는 담수-염수 비중 차이가 지하수위 변동에 영향을 미친다는 것을 파악할 수 있었다. 또한, 실제 지형에 적용하여 지하수위의 변동성을 분석하기 위해서, 제주 남부 중서귀 유역을 대상으로 수치모의를 수행하였다. 모형 검증은 범위 내 4개의 관측지점에서의 2022년 지하수위 자료를 이용하였다. 검증된 모델에 염분 농도 조건을 추가하여 기저지하수를 형성하여 모의를 수행했다. 따라서 본 연구는 부존 형태의 차이로 인해 발생되는 담수-염수 비중 차이가 지하수위에 끼치는 영향을 파악할 수 있었다. 향후, 상위지하수에서 염수가 침입했을 때, 수위 저하에 따라 감소되는 지하수위량을 예측할 수 있을 것이라 기대된다.

• Journal of Korean Society of Steel Construction
• /
• v.10 no.3 s.36
• /
• pp.437-449
• /
• 1998

In order that the steel girder and the concrete slab act as a composite structure, the connectors must have adequate strength and stiffness. If there are no horizontal or vertical separations at the interface, the connectors are described as rigid, and complete interaction can be said to exist under these idealized circumstances. However, all connectors are flexible to some extent, and therefore incomplete interaction always exists. This paper presents a practical structural analysis of composite girders with incomplete interaction by three methods. One is the stiffness matrix method derived from the general solutions of differential equation, another is the finite element analysis that alternate method of solution treats the structure as a frame and defines the spring as an additional member, and the other is the finite element analysis using principle of virtual work. The deflection characteristic of composite girder is investigated using these three methods. Also, this paper propose a simplified procedure of estimating a degree of imperfection for a composite girder with incomplete interaction using the sectional properties of girder and spring constants of shear connectors.

• Korean Journal of Social Welfare
• /
• v.64 no.3
• /
• pp.203-229
• /
• 2012

This study aims to analyze fundamental dilemmas of welfare-to-work programs, which aim to introduce labor market principles to the welfare system. Through a qualitative case study of a South Korean welfare-to-work program (the self-sufficiency program), this study demonstrates that various institutional problems are an inevitable consequence of such welfare-to-work programs because they have tried to combine two contradictory values and principles of the labor market system and the social welfare system in one policy. The analysis of the collisions between social welfare and market labor in the self-sufficiency program suggests that not only institutional reforms, but also profound debates on the values and principles underlying welfare-to-work programs are necessary to solve the phenomenal conflicts and problems with such programs.

• Proceedings of the Korea Society of Costume Conference
• /
• 2001.04a
• /
• pp.42-43
• /
• 2001

색상특성은 각 계열별로 차이가 있었으나 전반적 으로 고명도.저채도 중심으로 황색계열과 청색계열 은 고명도 위주의 분포특성을 보였다. 이어 반하여 적색계열은 비교적 색조의 영역이 넓었으며 고채도 의 분포특성이 두드러졌다. 자색계열은 저명도.중 채도, 녹색계열은 고명도.저채도 중심이었다. 남.녀복의 색조유형으로서 여복에서는 white보다는 tone 중심의 색조특성이 나타났으며. 남복에서는 white를 제외한 tint의 색조유형이 많았다. 이는 당시대인의 백색지향 의식을 대변하는 것으로 사료된다. 음양오행론의 배색원리에 의해 검토한 결과 여복 은 상생이 남복보다 낮게 집계되었으며, 반대로 파버 비렌의 색채조화의 배색원리에 의한 검토 철과는 남 복보다 여복의 적용수치가 높았다. 이것은 감각적인 색채조화 보다는 의례적인 성향이 좀 더 징한 남복이 서구의 색채조화의 척도에 적합하지 않은 결과로 추측된다. 전통복의 배색특성은 남녀가 매우 다른 양상을 보 이고 있었다. 여복의 기본 복식구조인 저고리/치마 는 백/청색계열, 백/황색계열과의 배색이 중심으로서 면적대비 및 명도대비에 의한 조화가 이루어지고 있었다. 반면에 저고리의 배색은 유채색과 백색계열 의 배색으로 채도대비의 성향이 강했다. 남복은 황/백색계열. 백/청색계열로 명도의 차가 크지 않았다. 포/띠의 의복 구성에 있어서는 흑색 또 는 적.자색 등의 세조대(細條帶)로 인해 채도대비, 면적대비, 명도대비의 배색효과를 찾아볼 수 있었다. 이상과 같은 분석결과를 통한 한국인의 색사용의 특정은 복식의 전면에 등장하는 백색지향과 음양오 행설을 그 배경으로 하고 있다. 백색위주의 색사용은 인공미가 배제된 자연미의 추구에 기인한 것으로 토착화된 한국의 색으로 볼 수 있다. 백색은 여러 색을 통합하고 배색된 색채착화된 한국의 색으로 볼 수 있다. 백색은 여러 색을 통합하고 배색된 색채들을 담하게 만드는 것이 특징 으로 한국전통 복식의 배색특성을 주도하고 있었다. 마지막으로 본 연구는 회화자료를 근거한 것으로 풍속화의 변색 및 탈색에 의해 당시대의 정확한 색채규명이 어려우며, 실물작품이 아닌 도판을 통한 측 색으로 색의 오차가 발생할 수 있음을 연구의 한계 점으로 언급하고자 한다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.17 no.2
• /
• pp.117-128
• /
• 1999

A Simple tree-structured line simplification method, which exactly follows the Douglas-Peucker algorithm, has a strength for its simplification index to be involved into the hierarchical data structures. However, the hierarchy of simplification index, which is the core in a simple tree method, may not be always guaranteed. It is validated that the local property of line features in such global approaches as Douglas-Peucker algorithm is apt to be neglected and the construction of hierarchy with no thought of locality may entangle the hierarchy. This study designed a new approach, CALS(Convex hull Applied Line Simplification), a) to search critical points of line feature with convex hull search technique, b) to construct the hierarchical data structure based on these critical points, c) to simplify the line feature using multiple trees. CALS improved the spatial accuracy as compared with a simple tree method. Especially CALS was excellent in case of line features having the great extent of sinuosity.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.17 no.4
• /
• pp.95-106
• /
• 2017

In this paper, we investigate the conventional topological interference management (TIM) with proposed network topology such as 8 trigram (8 user networks). The key observation is that optimal symmetric degree of freedom (DoF) can be achieved for 8 user network with different channel coherence times by adaptively selecting the interference alignment scheme via controlling the alignment feasibility of the transmitted signals. However, this yields a very complex problem, for which we use the combination of different schemes such as interference avoidance and repetition coding. In addition to the above schemes, we propose a triangular transmit cooperation (TTC) algorithm for 8 user networks to achieve the optimal symmetric DoF. And We apply the principle of complementarity of 8 trigram to remove the interferences, and correspond the concepts of win-win and conflict to direct and indirect signals of transmit and receive respectively. We find that the principle of complementarity comes out from the trigram of I Ching. That is, we apply the relation of confrontation and coexistence to 8 transmitters and receivers, and get the results of symmetric DoF of 4/3.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.37 no.7
• /
• pp.629-636
• /
• 2013

Pneumatic levitation is based upon Bernoulli's principle. However, this method is known to require a large gas flow rate that can lead to an increase in the cost of products. In this case, the gas flow rate should be increased, and the compressible effects of the gas may be of practical importance. In the present study, a computational fluid dynamics method has been used to obtain insights into Bernoulli levitation flows. Three-dimensional compressible Navier-Stokes equations in combination with the SST k-${\omega}$ turbulence model were solved using a fully implicit finite volume scheme. The gas flow rate, workpiece diameter,and clearance gap between the workpiece and the circular cylinder were varied to investigate the flow characteristics inside. It is known that there is an optimal clearance gap for the lifting force and that increasing the supply gas flow rate results in a larger lifting force.

• Journal of Korean Society of societal Security
• /
• v.1 no.3
• /
• pp.77-81
• /
• 2008

In this paper, we introduce a multi purpose environmental monitoring system developed as a commercially available standard using the technique of hetero-core spliced fiber optic sensor. The monitoring system has been tested and evaluated in a possible outdoor condition in view of the full scaled operation at actual sites to be monitored. Additionally, the developed system in this work conveniently provides us with various options of sensor modules intended for monitoring such physical quantities as displacement, distortion, pressure, binary states, and liquid adhesion. Two channels of optical fiber line were monitored, in each of which three displacement sensor modules were connected in series, in order to examine the performance to a pseudo-cracking experiment in the outdoor situation, and to clarify temperature influences to the system in terms of the coupling of optical connectors and the OTDR stability. The pseudo-cracking experiment successfully observed the actually given cracks by means of calculation based on the detected displacement values and their geometrical arrangement of the used sensor modules. And the robustness to the temperature is verified in the various temperature change.

• Archives of design research
• /
• v.11 no.1
• /
• pp.153-160
• /
• 1998

User, contents exchanged between user and computer system, and media are axes among the vanous factors related to multimedia interface. The points of contact resulted by three mam factors bring many design problems. User factor is most important among and its cognitive constraints become mam design principle for multi-modality features of multimedia. Because media could be understood differently depending on the level of information delivery, it is necessary that various characteristics and representation mode of media are clarified. This thesis develops design evaluation process that tells multimedia interface as a entity integrated with contents, media, and representation elements and assesses its sub elements whether they are correspond with design principal.