• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.30 no.3
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• pp.295-303
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• 2012

Clarify wind energy productivity depends on three factors: the wind probability density function(PDF), the turbine's power curve, and the air density. The wind PDF gives the probability that a variable will take on the wind speed value. Wind shear refers to the change in wind speed with height above ground. The wind speed tends to increase with the height above ground. also, Wind PDF refers to the change with height above ground. Wind analysts typically use the Weibull distribution to characterize the breadth of the distribution of wind speeds. The Weibull distribution has the two-parameter: the scale factor c and the shape factor k. We can use a linear least squares algorithm(or Ln-least method) and moment method to fit a Weibull distribution to measured wind speed data which data was located same site and different height. In this study, find that the scale factor is related to the average wind speed than the shape factor. and also different types of terrain are characterized by different the scale factor slop with height above ground. The gross turbine power output (before accounting for losses) was caculated the power curve whose corresponding air density is closest to the air density. and air desity was choose two way. one is the pressure of the International Standard Atmosphere up to an elevation, the other is the measured air pressure and temperature to calculate the air density. and then each power output was compared.

• Journal of Korean Society of Steel Construction
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• v.21 no.4
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• pp.375-384
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• 2009

The application of the diagrid structural system has increased of late, but cyclic loadings such as winds and earthquakes cannot be fully understood through only an analytical study due to the difficulty of considering its welding property. In this study, diagrid nodes that had been scaled down to 1/5 of their full sizes were tested to find out their structural behavior under seismic or wind loads. Four specimens were used with five parameters, including the welding method and the design details. Cyclic loading tests were carried out, where a tensile load was applied to one brace member and a compression load to the other. The major failure modes in the tests were only failure of bending with tensile stress and tension failure. The welding method and the design details had no effect on the initial stiffness and yielding stress but play a significant role in the failure mode and energy dissipation, respectively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.6 no.3
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• pp.273-277
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• 2005

We prepared $0.25\~l.5um$ poly silicon gate array test group with $SiO_2$ spacers in order to employ NiCo composite salicide process from 15nm Ni/15nm Co/poly structure. We investigate the residual metal shape evolution by varying the rapid thermal silicide anneal temperature from $700^{\circ}C\;to\;1100^{\circ}C$. We observed the residual metals agglomerated into maze type and line type on $SiO_2$ field and silicide gate, respectively as temperature increased. We propose that lower silicide temperature would be favorable in newly proposed NiCo salicide in order to lessen the agglomeration causing the leakage and scum formation.

• Journal of the Korean GEO-environmental Society
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• v.16 no.8
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• pp.45-49
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• 2015

Using 2D numerical analysis that covers the largest section of the dam body, a process is generally performed when evaluating its stability against seepage. The quantity of seepage is first obtained by assuming that its bottom topography is in the simple form of a rectangle, it is then calculated by reflecting its sectional shape during this process of analyzing the seepage quantity. Considering that various forms of dams are being constructed on various types of ground, thanks to more recent technological advances, it is judged more appropriate to draw a conclusion by means of the results on reflecting the realistic shape and topographical conditions of the dam body through 3D numerical analysis. Therefore, this study intends to present a method designed to carry out safety management by evaluating the correct quantity of water leakage that passes only through the dam body, having excluded other factors that include the amount of rainfall through the 3D FEM analysis.

• Journal of the Korea Convergence Society
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• v.12 no.11
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• pp.291-299
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• 2021

Recently, due to environmental problems caused by densification and high rise of urban areas, interests in air flow is increasing and appropriate shape and layout design of buildings is required. Therefore, in this study, we intend to propose an experimental method that can observe the air flow around a building using thermochromic pigment. Thermochromic pigments have limitations in observing precise temperature changes due to the characteristic that the color changes only with respect to a specific temperature, but they have the advantages of easy configuration of experimental equipment and short time required for experiments. In this study, the air flow tendencies around a building was examined by performing CFD analysis for a simple model and then compared with the thermochromic experiment results in order to review the usefulness of the proposed experimental method. As a result of the experiment, it was possible to observe the formation of separated flow and vortex region generated by buildings using the charateristics of thermochromic pigment and it was confirmed that the proposed method can be useful for buildings design and urban city planning.

• Journal of the Korean Geotechnical Society
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• v.23 no.10
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• pp.121-131
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• 2007

This study is to investigate the damage assessment of adjacent structures due to excavation in urban environment. Model tests were carried out for 2 story masonry building and frame structures in various shapes and locations. The damage level of adjacent structures were very differently estimated in accordance with the shape ratio (L/h) of structures, construction stages, and various locations. Therefore the most weak part (bay) of structure must be heavily instrumented and monitored in more details at early stage of constructions. The progressive crack development mechanism at various construction stages was revealed through model tests and crack size indicated more conservative side of damage level on the damage level graph.

• Journal of the Korean Institute of Gas
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• v.20 no.3
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• pp.73-77
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• 2016

This paper presents the displacement behavior safety of hollow shafts with an equivalent volume for various cross sectional area using a finite element method. The FEM results indicate that the hollow shafts with X-type or Y-type columns between outer tube, middle tube and inner tube may reduce a maximum displacement at the middle length of hollow shafts. Especially, the load-bearing column of X-type or Y-type hollow shaft is directly connected between outer tube and inner tube without a shift for reducing the vertical displacement. And increased thickness of a load-bearing column is recommended for reducing the vertical displacement and increasing the displacement behavior safety for an equivalent volume of a hollow shaft.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.1716-1720
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• 2006

침투는 지반이 충적토로 구성되어 있는 제방의 파괴를 야기하는 중요한 원인이다. 침투 해석 수치모형은 제방 침투와 관련된 문제 해석과 방지기법 설계에 있어 매우 유용한 방법이나, 각각의 수치모형은 적용상 한계와 문제점을 내포하고 있다. 실제 지하수 흐름은 간극률, 입자형상 및 크기, 포화도 등과 같은 토질특성, 내부침식과 같은 역학적 특성, 점성과 동결융해 같은 열역학적 특성, 그리고 화학적 특성 등 다양한 인자의 영향을 받는다. 이러한 물리적 인자 이외에도 침투 수치해석은 외력조건, 격자 크기(element size), 그리고 시간 간격(time step interval) 등 입력조건에 영향을 받기 때문에 이들 설정에 대한 검토를 시행하여야 한다. 본 연구에서는 침투 수치모형의 적절한 입력조건 범위를 검토하였으며, 격자크기는 계산시간과 해석결과 등 수치모의의 효율성을 고려하였을 때 홍수위 혹은 제방고의 1/10이하로 결정하면 타당할 것으로 판단된다. 그리고 침투수치모형의 시간 간격은 외력조건을 고려하여 1시간 이내로 설정하는 것이 바람직할 것으로 판단된다. 본 연구결과는 침투해석 수치모의의 유의사항을 검토하여 해석결과에 대한 불확실성과 위험요소를 제거하는데 도움이 될 것으로 판단된다.

• The Journal of the Acoustical Society of Korea
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• v.19 no.2
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• pp.3-7
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• 2000

This paper is on the sensitivity characteristics of a concentric composite mandrel type fiber optic acoustic sensor with inclusion of an air cavity With the finite element method, we have analyzed sensitivity variation of the sensor in relation to its geometrical factors such as thickness of the air cavity, thickness of the foaming layer, and the ratio of inner diameter/outer diameter of the mandrel. Results of the analysis suggest a thicker air cavity, a thinner foaming layer, and a smaller ratio of the inner diameter/outer diameter of the mandrel to be desirable for higher sensitivity. The sensor structure designed with the above rules provides the sensitivity of about 0.8dB higher than that of a normal concentric composite mandrel sensor without the inherent air cavity.

• Korean Architects
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• no.8 s.352
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• pp.57-57
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• 1998

오늘날의 수원은 도청소재지로서, 서울의 인접도시로서, 수도권의 주요도시로서 다양한 가치를 가지고 존재하고 있다. 이 땅의 어느 곳에나 먼 옛날부터 여러가지 사연들을 가지고 사람들이 살아왔겠지만, 수원은 200년전 어떠한 사연으로 여기에 사람들이 모여 살게 되었고, 도시의 구조는 어떻게 구성되었으며, 오늘까지 어떻게 지내왔는가 하는 것이 다른 도시보다 정확하게 기록되어 있는 드문 도시로서 그 탄생과 성장의 역사를 후손들이 들추어 볼 수 있어, 많은 사람들의 관심을 끌어 왔다. 더구나 1997년에는 유네스코 인류문화유산으로 수원의 화성이 등록되면서 다시 성곽이라는 물리적 요소와 200년이라는 세월 속에 이루어진 공간과 역사는 이 도시의 존재가치와 앞으로 걸어가야 할 길을 진지하게 모색하도록 하였다. 조선조말에 접어들면서 이 땅에서 우리 나름대로 근대의 싹이 돋아 나오던 시절, 새로운 바람이 지식인들과 통치자들 사이에 일어, 수원에 계획도시를 건설하였다. 새로운 사회와 체제를 시도하고 이에 대한 도전을 찬찬히 진행하면서 이 도시의 형상을 갖추어 갔다. 중앙으로부터 시작된 개혁과 변화는 큰 힘을 얻지 못하였고 정조 이후의 수원은 서울과 지방을 잇는 통과도시로서만 역할을 하였다. 근대화하는 과정에서는 농업기술개발의 중심지로서, 산업화 과정에서는 섬유ㆍ전자산업의 본산으로서 도시의 세를 넓혀 나갔다. 최근 들어 우리들의 삶이 문화에 눈을 돌릴 정도로 성숙해져서 이 고장의 정체성에 대해 논하고 많은 사람들이 찾아내려는 노력을 하고 있다. 일상생활과 상관없던 시민들이 생각하고, 새로 맞는 또한 세기에는 화성과 맞먹는 이 시대의 수원다움을 만들어 나가야 하는 것이 이 시대를 사는 사람들의 과제일 것이다. 숱한 과제가 건축사들에게 주어져 있지만 언제나 힘겨운 것이었고 시원한 답을 만들지 못하였다. 그만큼 우리는 눈을 늦게 떴고, 그러는 사이에 도시는 풀어내기 어려운 상태로 변화되어 갔다. '건축사'의 기획 시리즈 수원편을 통하여 지나온 과거를 정리하고 현재의 모습을 살펴보고, 이제부터 우리가 해야 할 일들에 대하여 생각해 보았다.