• 한국게임학회 논문지
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• 제15권6호
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• pp.171-182
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• 2015

지형에 대한 기존의 침식 시뮬레이션은 주로 소규모의 지형 변화에 초점을 맞추고 있다. 이 논문에서는 물에 의한 침식과 열적 침식과정을 결합하여 강의 네트워크와 산들로 이루어진 자연스러운 대규모의 지형을 형성하는 방법을 제안한다. 물의 흐름에는 shallow water 시뮬레이션의 파이프 모델을 사용하며, 강물의 줄기가 쉽게 형성되게 하기 위해 속도에 의존하는 침식을, 강줄기 주변에 V자형 골짜기가 생성되게 하기 위해 열적 침식을 적용한다. 시뮬레이션 결과 $K_c$(퇴적물 수용상수)와 $K_v$(속도의존 침식강도)의 값이 적당한 범위에 있을 때만 목적한 모양의 지형이 생성되며, 이렇게 생성된 대표적인 자연스러운 모양의 지형을 예시한다. 또한 기존의 열적 침식 방법의 개선과 $K_c$가 큰 값일 때 발생하는 문제점을 해결할 방안을 제시한다.

• 한국환경과학회지
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• 제19권3호
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• pp.281-293
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• 2010

The present study explores time and spatial thermal environment for Daegu, which is a city built on a basin area, according to varying land cover conditions of the earth's surface by analyzing data derived from meteorological observation and satellite images. The study has classified land use by utilizing MODIS satellite images and analyzed land surface temperature. Also, by using data acquired from automatic weather system, the study has evaluated the effects of atmospheric heating caused by city pavements by analyzing the sensible heat flux between the city's land surface and the atmosphere. The results are as follows. 1) Classification of land use in the Daegu area shows 46.64% of urban and built-up area, 1.39% of watersides, 35.19% of forest, 11.43% of crops, and 5.37% grasslands. 2) During the weekdays throughout the year, the land surface temperature was high for Dalseogu, Bukgu, and Seogu regions where industrial complexes could be found. Comparatively, lower temperature could be observed in the woodlands. 3) While the land surface temperature displayed the effects of pushing air upwards during the weekdays in urban areas, the reverse was true for forest regions. During the night, the temperature did not exert any significant influence on air movement.

• Journal of Welding and Joining
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• 제17권1호
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• pp.104-115
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• 1999

판재의 비드 용접과정에서 열응력과 각변형의 발생기구 및 크기를 판재 단면에 대한 2차원 유한 요소해석을 통해 규명하고자 할 때 판재의 3차원 특성을 판재 길이의 크기효과로 간주하여, 구속경계조 건으로 설정함으로써 2차원 해석으로도 더욱 실제에 근접한 현상해석이 가능함을 제안하고자 하였다. 먼저 용접 입열에 의한 판재 내부의 천이 온도분포를 해석하였고, 이를 열응력 해석에 활용하였다. 2차 원 열응력 해석에 있어, 용접도중에 단면 전체가 길이 방향으로 동일한 크기의 변위를 한다고 가정하여 일정 변위를 길이 방향 경계조건으로 설정하고, 판재의 길이에 따라 각변형의 발생이 구속된다고 가정 하여, 판재의 길이에 의한 구속효과를 상당 구속력으로 간주하여 이를 단면 부재의 회전방향에 대한 경 계조건으로 설정함으로써 판재의 3차원 특성을 고려하고자 하였다. 제안된 방법에 의한 응력 분포 형태, 각변형 크기 등의 해석 결과가 기존의 2차원 해석 결과에 비해 실제에 더 근접함을 보여 주었다.

• 대한임베디드공학회논문지
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• 제17권1호
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• pp.33-40
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• 2022

With the recent increase in the development of military drones, they are adopted and used as the combat system of battalion level or higher. However, it is difficult to use drones that can be used in battles below the platoon level due to the current conditions for the formation of units in the Korean military. In this paper, therefore, we developed a program drones equipped with a thermal imaging camera and LiDAR sensor for reconnaissance and exploration that can be applied in battles below the platoon level. Using these drones, we studied the possibility and feasibility of drones for small-scale combats that can find hidden enemies, search for an appropriate detour through image processing and conduct reconnaissance and search for battlefields, hiding and cover-up through image processing. In addition to the purpose of using the proposed drone to search for an enemies lying in ambush in the battlefield, it can be used as a function to check the optimal movement path when a combat unit is moving, or as a function to check the optimal place for cover-up or hiding. In particular, it is possible to check another route other than the route recommended by the program because the features of the terrain can be checked from various viewpoints through 3D modeling. We verified the possiblity of flying by designing and assembling in a form of adding LiDAR and thermal imaging camera module to a drone assembled based on racing drone parts, which are open source hardware, and developed autonomous flight and search functions which can be used even by non-professional drone operators based on open source software, and then installed them to verify their feasibility.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2001년도 춘계학술대회 논문집
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• pp.379-386
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• 2001

Fluid viscous dampers have been used as energy dissipators or STU's (Shock Transmission Unit) in earthquake resistant designs for bridges. Viscous dampers have many advantages compared to other friction type or visco-elastic type of dampers. They do neither increase internal pier forces due to their out of phase response, nor produce reaction forces at the low velocities associated with thermal movements. Therefore, they anable the super structure to restore itself perfectly after a severe movement dut to seismic excitations. This paper investigates the response of bridges designed with viscous dampers in regard to damping coefficients, properties of dampers, and arrangements of dampers. For this purpose, time-history dynamic analyses have been performed using a very simple model relevant to a typical bridge example. Based on the results, it presents some design duidelines on how to determine a proper damping ratio and on how to arrange dampers. In usual cases, damping coefficients corresponding to about 0.2-0.3 of damping ratios seem to be very effective in bridge designs.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.660-663
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• 2001

There is a mechanical device between the superstructure and substructure of a bridge, which transmit vertical load of superstructure to the substructure and absorb horizontal displacement of super structure due to thermal, dynamic, load, etc. In order to meet two requirements at once, the structure of roller between plates is widely used, and this roller between plates is widely used, and this roller shoe system is known to have smaller horizontal movement resistance than any other type of bridge shoe. In this study, rolling friction resistance characteristics of roller-plate friction system is investigated according to roller dimension, vertical load, hardness and roughness of roller and plate. On the base of the results, the rolling friction resistance of large scale roller shoe is evaluated using model experiment.

• Journal of Advanced Marine Engineering and Technology
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• 제34권7호
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• pp.981-990
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• 2010

The main objective of this study is to investigate the fluid flow and the heat transfer characteristics of nanofluids using multi-phase thermal LBM and to realize theenhancement of heat transfer characteristics considered in the Brownian motion. In multi-phase, fluid component($H_2O$) is driven by Boussinesq approximation, and nanoparticles component by the external force gravity and buoyancy. The effect of Brownian motion as a random movement is modified to the internal velocity of nanoparticles(Cu). Simultaneously, the particles of both the phases assume the local equilibrium temperature after each collision. It has been observed that when simulating $H_2O$-Cu nanoparticles, the heat transfer is the highest, at the particle volume fraction 0.5% of the particle diameter 10 nm. The average Nusselt number is increased approximately by 33% at the particle volume fraction 0.5% of the particle diameter 10 nm when compared with pure water.

• 한국결정학회지
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• 제12권3호
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• pp.166-170
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• 2001

실리콘 기판에 도핑되어 있는 도판트는 종류에 따라 코발트와 실리콘 기판과의 반응에 영향을 준다. 인은 붕소나 비소에 비해 코발트와 실리콘과의 반응을 억제하여 저온 열처리 동안에 CoSi₂대신에 CoSi가 형성되도록 한다. CoSi층 내에서의 확산원소는 Si으로, CoSi 층은 Co/CoSi 계면에서 성장하며 반응에 참여하는Si 소모에 의해 생기는 기판의 빈 공간을 태우기 위해 Si 기판쪽으로 이동한다. 게이트 측벽에서는 접촉되어 있는 게이트 산화막과의 결합에 의해 CoSi층의 이동이 억제된다. 따라서 기판의 빈 공간을 태우지 못하게 되어 게이트 측벽 아래에 기공이 형성된다.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 추계학술발표회
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• pp.213-216
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• 2003

Efforts for better understanding of the interaction between groundwater recharge and thermal regime of the subsurface medium is gaining momentum for its diverse applications in water resources. A numerical model is developed to simulate temperature variations of the subsurface under time varying groundwater recharge. The model utilizes MacCormack scheme for finite difference approximation of the partial differential equation describing the conductive and advective heat transport. For the estimation of recharge rate, optimization of the model is realized by searching for the unknown parameters which minimize the root-mean-square error between simulated and measured temperatures. Simulation results for 22-year time series data of temperature measurements reveal that the proposed model can accurately simulate subsurface temperature variations resulting from the redistribution of the heat due to the movement of water and it can also estimate temporal variations of recharge. Seasonal variations of recharge and a linear relationship between precipitation and recharge are clearly reflected in the simulated results.

• KIEAE Journal
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• 제2권4호
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• pp.21-26
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• 2002

Modem architecture represent a great capitalistic, polishing, high-technology image to the public by design. As a result, glass architecture which show 'transmittance' in desinging play a leading part, consequently a role of machine is increasing in controlling an internal environment of building. These movement look like assisting an universal standard building disregarding a each nation's climate peculiarity, if glass building is applied by a proper external shading device. the shading device has a great effect on the reduction of cooling load energy, this research to propose the proper designing scheme of the fixed external shading device. The effect of proper external shading device on the cooling load is evaluated by the numeric simulation.