• 한국대기환경학회지
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• 제16권4호
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• pp.327-338
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• 2000

complexity in atmospheric environment coupled with shoreline and complex terrain often causes local variations of meteorology that are distinct from those representative over larger surrounding area, These kinds of local variations are less significant in usual long-term environmental impact analyses dealing with continuous plume. The variations could however be crucial in predicting dispersion of toxic substance released in a relatively small area for a short duration. In the present paper the effects of spatial and temporal resolution of diagnostic wind field on the dispersion of the released substance are investigated by using a puff model. A hypothetical release scenario assumes that a substance is released from a location in the Yochon Industrial Estate and passively dispersed within a few-kilometer distance for an hour. The results show that diagnostic analysis could resolve more spatial variations to some extent by employing smaller grid size. The peak concentrations and puff trajectories obtained from spatially -and/or tmeporally -varing diagnostic wind field are found appreciably different from those obtained from uniform wind field. Attention to high-resolution wind field in the both spatial and temporal spaces is called in the consequence analysis of toxic substance release.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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• pp.242-242
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• 2002

The Earth's magnetic field acquired from KOMPSAT-1's TAM (Three-Axis Magnetometer) between June 19th and 21st 2000 was analyzed. The TAM, one of the KOMPSAT-1's Attitude and Orbit Control Subsystems, plays an important role in determining and controlling the satellite's attitude. This also can provide new insight on the Earth's magnetic field. By transforming the satellite coordinate from ECI to ECEF, spherical coordinate of total magnetic field was achieved. These data were grouped into dusk (ascending) and dawn (descending) data sets, based on their local magnetic times. This partitioning is essential for performing 1-D WCA (Wavenumber Correlation Analysis). Also, this enhances the perception of external fields in the Kompsat-1's TAM magnetic maps that were compiled according to different local. The dusk and dawn data are processed independently and then merged to produce a total field magnetic anomaly map. To extract static and dynamic components, the 1-D and 2-D WCAs were applied to the sub-parallel neighboring tracks and dawn-dusk data sets. The static components were compared with the IGRF, the global spherical harmonic magnetic field model. The static and dynamic components were analyzed in terms of corefield, external, and crustal signals based on their origins.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.1225-1230
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• 2004

The effects of substrate material on the local heating performance of microheaters are studied by both numerical analysis and experiment. Transient conduction analysis shows that the substrate material with low thermal conductivity is critical to the local heating and fast response. A measurement technique for surface temperature field in microscale is newly proposed, which uses temperature sensitive fluorescent dye coated on the surface. The measured surface temperature fields on microheater arrays fabricated on different substrates are presented.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.1298-1303
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• 2008

In Korea, the management and remedial system of the slope near national road and highway has been studied actively. But in case of the slopes exist at the residential area and local government, there is not exact record of them. So in this study, we carried out analysis about nearly 14000 slopes which were reported by local government as the dangerous area. and went to the field work some of them.

• 한국환경과학회지
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• 제9권2호
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• pp.101-108
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• 2000

Through numerical experiment using simplified OSU-1D PBL(Oregon State University One-Dimensional Planetary Boundary Layer) model and field measurement, we studied the impacts of vegetation canopy on heat island that was one of the characteristics of local climaate in urban area. it was found that if the fraction of vegetation was extended by 10 percent, the maximum air temperature and the maximum ground temperature can come down about 0.9${\circ}C$, 2.3${\circ}C$, respectively. Even though the field measurement was done under a little unstable atmospheric condition, the canopy air temperature was lower in the daytime, and higher at night than the air and ground temperature. This result suggests that the extention of vegetation canopy can bring about more pleasant local climate by causing the oasis, the shade and the blanket effect.

• Computers and Concrete
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• 제1권3호
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• pp.227-248
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• 2004

A combined experimental-computational study of a double edge-notched stone specimen subjected to tensile loading is presented. In the experimental part, the load-deformation response and the displacement field around the crack tip are recorded. An Electronic Speckle Pattern Interferometer (ESPI) is used to obtain the local displacement field. The experimental results are used to validate a numerical model for the description of fracture using finite elements. The numerical model uses displacement discontinuities to model cracks. At the discontinuity, a plasticity-based cohesive zone model is applied for monotonic loading and a combined damage-plasticity cohesive zone model is used for cyclic loading. Both local and global results from the numerical simulations are compared with experimental data. It is shown that local measurements add important information for the validation of the numerical model. Consequently, the numerical models are enhanced in order to correctly capture the experimentally observed behaviour.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2007년도 제28회 춘계학술대회논문집
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• pp.212-216
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• 2007

Predicting microcracking properties of the composite laminates in nonuniform stress conditions was the subject in this paper. The uniform stress field meant the stresses were independent of the width direction. The material was the 954-2A/IM7 laminates containing a central hole. Microcracks initiated at the edge of the hole and propagated into the laminate. Because the tensile stress concentration decreased with distance, the microcracks were arrested before the edge of the laminate. Because carbon fiber composites were opaque, a x-ray method was used to detect the length of the propagating microcracks. The microcracking at the near edge of the hole could be reasonably predicted by considering the local laminate stresses and the microcracking toughness measured in unnotched laminates. However, the date away from the hole did not agree with the predictions. The local microcrack density was always much higher than that predicted by the local laminate stress.

• Progress in Superconductivity
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• 제13권1호
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• pp.34-39
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• 2011

본 연구를 통해서 초전도 선재 시료의 국소적인 영역에 대한 전류 밀도의 공간적인 분포를 시료의 손상 없는 비파괴적인 방법으로 LTSHPM을 통해서 1차원 2차원으로 형상화해 보았다. 그 결과 외부자기장에 의한 차폐전류의 흐름을 분석할 수 있었다. 또한 MPMS에서 외부자기장에 따른 자기모멘트를 측정한 결과와 LTSHPM을 통해 전류 밀도 분포를 분석한 결과를 비교해 볼 때 외부자기장에 의한 반자성의 크기와 자기모멘트로 인해 생기는 차폐전류가 100 Oe에서 최댓값을 가지는 일치하는 결과를 얻을 수 있었다. 그리고 세 가지의 평행한 브릿지에 흐르는 차폐전류를 2차원적으로 분석해 본 결과 시료 전체적으로 가장 바깥쪽으로 차폐전류가 흐르는 공통점을 확인해 볼 수 있었다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
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• pp.277-280
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• 2007

Field emission-back light unit (FE-BLU) was fabricated using carbon nanotube (CNT) emitter. Local dimming and local brightening techniques were achieved, which results in very high contrast ratio. In addition, the motion blur phenomenon, one of the serious problems of liquid crystal display (LCD) with cold cathode fluorescent lamp (CCFL)-BLU, was removed from LCD-TV by using FE-BLU.

• 국제초고층학회논문집
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• 제11권4호
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• pp.287-300
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• 2022

Unconventional structures are getting more popular in recent days. Large-span roofs are used for many structures, such as airports, stadiums, and conventional halls. Identifying the pressure distribution and wind load acting on those structures is essential. This paper offers a collaborative study of computational fluid dynamics (CFD) simulations and wind tunnel tests for assessing wind pressure distribution for a building with a combined slender curved roof. The hybrid turbulence model, Improved Delayed Detached Eddy Simulation (IDDES), simulates the open terrain turbulent flow field. The wind-induced local pressure coefficients on complex roof structures and the turbulent flow field around the structure were thus calculated based upon open terrain wind flow simulated with the FLUENT software. Local pressure measurements were investigated in a boundary layer wind tunnel simultaneous to the simulation to determine the pressure coefficient distributions. The results predicted by CFD were found to be consistent with the wind tunnel test results. The comparative study validated that the recommended IDDES model and the vortex method associated with CFD simulation are suitable tools for structural engineers to evaluate wind effects on long-span complex roofs and plan irregular buildings during the design stage.