• Korean Journal of Agricultural and Forest Meteorology
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• v.15 no.1
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• pp.9-16
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• 2013

Coastal sand dune area is an important ecosystem as an ecotone which is located between coastal area and terrestrial area. In order to understand the sand dune ecosystem in terms of its habitat characteristics, micrometeorological analysis was carried out in a coastal sand dune in Hakampo, Taeanhaean National Park, Korea. Micrometeorological measurements were made to monitor air and soil temperatures, relative humidity, soil water content, rainfall, solar radiation, wind speed, and wind direction. In contrary to a forest ecosystem, the coastal sand dune grassland ecosystem was relatively hotter and very humid with heavy rainfalls concentrated between June and July. The seasonal change of daily mean soil temperature was greater than that of air temperature by $2{\sim}3^{\circ}C$. Daily mean soil water content was less than 10% throughout the year. Also, the maximum wind speed of 156.7 m $s^{-1}$ was recorded on 7 October 2011. The observed seasonal wind direction was different from those observed at Seosan by KMA (Korea Meteorological Administration). To better understand the habitat characteristics in a costal sand dune grassland ecosystem, long-term multi-year measurements are needed.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2014.06a
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• pp.17-19
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• 2014

해양사고 발생 직후 2차적인 피해로의 확산을 방지하기 위한 조치로 사고선박을 안전한 장소로 이동하게 된다. 사고선박의 크기와 상태 그리고 해상조건을 고려하여 예선의 크기와 척수가 결정된다. 이 과정에서 사고선박의 선체저항을 계산하게 되는데, 기존의 이론식을 적용하여 계산하고 이에 대한 검증 단계로 예인실험을 실시하였다. 대상선박은 목포해양대학교 실습선 새유달호이며, 장력계, 외력 측정장치 등 실험장치는 실습선에 탑재하여 계측하였다. 실험장소는 목포해양대학교 인근 묘박지이며, 당시 풍속은 7m/s, 조류는 0.7m/s 전후이었으며, 횡방향 예인, 전방 2척 예인, 전 후방예인, 프로펠러고착, 예인속력의 변화 등 다양한 시나리오에 대하여 실험을 실시하였다. 장력의 계측은 예선의 예인삭을 사용하였으며, 실습선 선수미 비트에 장력계를 연결하여 측정하였고, 장력계의 최대측정 범위는 20톤을 사용하였다. 예인속력은 정지에서 3m/s까지 단계적으로 증가시키면서 해당 속력별 장력을 계측하여 속력증가에 따른 예인력을 확인하였다. 최종적으로 이론계산 결과와 실선실험 결과를 상호 비교하여 이론계산식의 유효성을 검증하였다.

• KOREAN POULTRY JOURNAL
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• v.36 no.7 s.417
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• pp.70-74
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• 2004

최근 육종개량의 발전과 성과로 인하여 대형화되었지만 고밀도 사육에 의해서 하절기 열사병과 심한 더위로 인한 생산성 저하가 큰 문제로 혹서기에 대두되고 있어 그 대응책을 반드시 세워야 할 것이다. 하절기 온도관리 대책으로서는 계사내의 공기유통을 좋게 하는 것이 가장 기본이므로 충분한 환기에 의해 닭의 체감온도를 낮추어 주게 되는 것이다. 그러나 우리나라와 같이 여름철의 기후 특성이 고온다습한 경우는 습도가 높아지게 되면 체감온도는 낮아지지 않는다. 그러므로 계사내의 습도를 저하시키기 위해서 환기휀 등을 이용해 깔짚과 계분을 건조시키는 것도 한가지방법이다. 일반적으로 열사병 대책으로 실시하고 있는 방법으로서는 입기구에 물 분무, 지붕에 물 분무, 계사내의 미세한 분무냉각 등 물을 이용하는 방법이나, 환풍기의 설치, 닥트송풍을 이용한 방법, 거칠고 얇은 그물에 의한 차광 등의 방법으로 온도를 낮게 할 수가 있다. 특히 산란계의 경우 여러 연구보고 자료에 의하면 산란계를 고온 환경에서 사육할 경우 난각질이 저하된다고 하는 보고가 많이 있다. 1일 중에 환경온도를 주기적으로 변화시킨 경우는 일정하게만 유지해 주는 환경온도에 비해서 난각질과 난각강도는 낮아지게 된다. 또한 산란계에 있어서 간헐점등에 대해서는 에너지 수준을 줄이는 기술, 또는 사료절감을 유도하는 방법은 계속 연구되고 있다. 따라서 다음은 하절기 산란$\cdot$육계사의 적온유지를 위한 온도관리 사례에 대하여 이야기하고자 한다.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.597-600
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• 2010

본 연구에서는 한강 상 교량인 올림픽대교를 대상으로 첨단 무선센서를 구조물 주요 부재에 설치하고 본 센서를 통해 취득되는 데이터를 활용하여 실시간 구조 건전도 모니터링 시스템을 구축하는 것을 목적으로 하였다. 본 시스템은 유비쿼터스 센서 네트워크(USN, Ubiquitous Sensor Network)기술을 적용하여 림픽대교 주요 구조 부재 모니터링을 위한 센서 및 데이터 로깅 시스템으로 구성되어 운영된다. 본 연구에서는 1축 가속도계, 3축가속도계, 온도계, 경사계, 풍향풍속계 5종의 무선 센서를 총 10개 설치하였으며, 센서의 전원은 태양광 자가 전원공급 시스템으로 하였다. 데이터는 시스템 구축완료 후 9월1일부터 9월 7일까지의 일주일간의 데이터를 활용하여, 기존에 설치되어 있던 유선시스템으로부터 취득된 데이터와 비교분석하였으며, 이를 통행 USN 기반의 교량 계측시스템에 대한 실용성을 검증하였다.

• Journal of the KSME
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• v.29 no.5
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• pp.507-519
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• 1989

랜덤 신호의 앙상블 통계 처리 방법은 학교 실험실에서나 연구소 실험실 및 산업계 현장의 계측 시스템에 있어서 그 적용 가능성이 매우 커 이에 대한 파급성이 매우 증가할 것으로 생각된다. 특히 본 방법은 값싼 계측 기자재 등으로 구성하여 보다 정확한 자료를 추출함에 있어 최대의 효과를 내고자 한 점이 가장 크게 평가될 수 있을 것으로 사료된다. 한편 열. 유체 유동중 난류 계측에 본 방법을 적용하였을 경우 얻을 수 있는 결과들은 무엇보다도, 열선풍속계, A/D변환기, 컴퓨터 등으로 온라인이 가능하여 유동장내 임의 한 위치에서 분석에 필요한 많은 데이터들은 랜덤신호의 동시 계측 및 연산을 통해 쉽게 얻을 수 있으므로, 한 점을 통과하는 난류 랜덤 신 호로부터 통계학적인 난류 유동 특성의 거동을 보다 쉽게 분석할 수 있다는 점이다. 또한 본 방법을 이용하면, 압력 변환기 및 열전대에서 발생되는 랜덤 신호로부터 열. 유체 유동 등을 통 계학적으로 보다 광범위하게 분석할 수 있게 된다. 끝으로 본 연구에서 언급한 랜덤 신호의 앙 상블 개념의 통계 처리 방법은 현재 널리 보급된 소형 컴퓨터 IBM-ST/AT급에서도 쉽게 적용이 가능하기 때문에 많은 이용이 될 것으로 기대되는 바이다.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.40 no.2
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• pp.138-143
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• 2004

This experimental paper deals with the performance of tanks that are turned the active A.R.T(Anti-Rolling Tank) when the fluid transfers from wing tank to the opposite tank by the power developed by the automatic control system (INTERING Stabilizer), which was installed in the fishery training ship T/S. A - RA (G/T:990 tons) of Cheju National University. In this paper, the author has tested the performance of INTERING Stabilizer for the signals obtained by the inclinometer in irregular waves and compared with the results obtained in passive mode operation at stop and at various ship speeds. The performances of the system were confirmed the results as follows through the tests: 1. The average amplitude and significant roll (${\pi}$1/3) of the passive and active mode operations in the condition of stoped engine and underway were obtained 8.30$^{\circ}$, 4.37$^{\circ}$, 8.30$^{\circ}$, 4.37$^{\circ}$, and 5.01$^{\circ}$, 4.36$^{\circ}$, 5.50$^{\circ}$, 5.10$^{\circ}$, respectively. 2. The rates of performance of active mode operations were carried out during a sea trial in the condition of stop engine and underway resulted in 47.5%, 12.7%, respectively, therefore the active mode operation estimated to be improved more than passive mode operation. 3. Active - A.R.T by INTERING Stabilizer didn't affect the amplitude of pitching.

• Korean Journal of Agricultural and Forest Meteorology
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• v.15 no.4
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• pp.210-218
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• 2013

The sea breeze shows different characteristics compared to land breeze, such as high wind speed and more rapider shift period. One of the major factors affecting plant early growth is wind speed. In the early growth stage, tree growth-rates rise with decreasing wind speed. Thus, the study was performed to identify wind break effects on wind characteristics and tree growth. The wind break used in this study was about 130 meters length and 3 meters height, made up with poly-ethylene (with 40% openness). We installed one vane and fifteen anemographs at three different heights (1, 2 and 3 meters) on the inner and outer wind break areas. The wind characteristic and plant growth data were collected from Jun. 2011 to Oct. over 2012. The wind rose of the Saemangum seawall area presented the north (21.5%) and it was followed by north-west (18.1%), east (14.9%) and north-east (13.7%) and the remainder with other directions. Wind speeds at height were different. The tree height was 159.6 cm at inside and 129.6 cm at outside. The diameter at root-collar was 36.9 mm at inside and 32.6 mm at outside from wind break.

• Journal of the Korean Society of Hazard Mitigation
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• v.6 no.3 s.22
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• pp.47-56
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• 2006

With the aim to develop the monitoring technology on background atmosphere and climate change over Korean Peninsula, observations and studies on chemical, physical and optical properties of the atmospheric aerosols are made. Aerosol number concentration are measured with Optical Particle Counter from 2001 to 2003 at Gosan for 8 size intervals from 0.3 to $25{\mu}m$ diameter range. For the seasonal variation, the number concentration of coarse particles in spring at Gosan was higher than other seasons due to the influence of sand storm in spring. There is no significant correlations between fine particles ($0.3{\sim}0.5{\mu}m$) and meteorological parameters, such as relative humidity, wind speed and visual range, while the correlation between the number concentration of small particles ($0.5{\sim}2.23{\mu}m$) and relative humidity showed a positive value. This trend was inversed for the case of wind speed: aerosol number concentration showed a small decreasing tendency with increasing wind speed for small particles but the high wind speed in winter season increased coarse particle concentration. Finally, Particles most efficient in light extinction were found to be at the size of about $0.5{\sim}1{\mu}m$.

• Korean Journal of Remote Sensing
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• v.36 no.6_3
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• pp.1643-1652
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• 2020

To investigate the characteristics of detailed flows in a building-congested district, we coupled a computation fluid dynamics (CFD) model to the local data assimilation and prediction system (LDAPS), a current operational numerical weather prediction model of the Korea Meteorological Administration. For realistic numerical simulations, we used the meteorological variables such as wind speeds and directions and potential temperatures predicted by LDAPS as the initial and boundary conditions of the CFD model. We trilinearly interpolated the horizontal wind components of LDAPS to provide the initial and boudnary wind velocities to the CFD model. The trilinearly interpolated potential temperatures of LDAPS is converted to temperatures at each grid point of the CFD model. We linearly interpolated the horizontal wind components of LDAPS to provide the initial and boundary wind velocities to the CFD model. The linearly interpolated potential temperatures of LDAPS are converted to temperatures at each grid point of the CFD model. We validated the simulated wind speeds and directions against those measured at the PKNU-SONIC station. The LDAPS-CFD model reproduced similar wind directions and wind speeds measured at the PKNU-SONIC station. At 07 LST on 22 June 2020, the inflow was east-north-easterly. Flow distortion by buildings resulted in the east-south-easterly at the PKNU-SONIC station, which was the similar wind direction to the measured one. At 19 LST when the inflow was southeasterly, the LDAPS-CFD model simulated southeasterly (similar to the measured wind direction) at the PKNU-SONIC station.

• Journal of Environmental Impact Assessment
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• v.32 no.6
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• pp.437-449
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• 2023

This study measured PM₁₀ concentrations and wind speeds in buffer green spaces and neighborhood parks located along the road, and compared them with roadside measurementresults to understand the effect of mitigating PM₁₀ concentrations by type of green space and the influence of wind speeds on it. As a result of the analysis, the effect of mitigating PM₁₀ concentration was different depending on the type of roadside green space, and an increase in wind speed had a significant effect on reducing PM₁₀ concentration. In buffer green areas with high planting density, wind speed was low and PM₁₀ stagnated inside, resulting in the highest concentration. On the other hand, green areas in neighborhood parks with relatively low planting density had high wind speeds and the lowest PM₁₀ concentration. The non-green area within the neighborhood park recorded the highest wind speed, which was advantageous for the spread of PM₁₀, but the concentration was higherthan that of the green area. Therefore, in orderto reduce PM₁₀ concentration in roadside green space, it is necessary to create green space with good ventilation, and the combined effect of green space and wind speed seems to be more advantageous in reducing PM₁₀ concentration. Green spaces capture and remove PM inside, contributing to reducing the concentration of PM outside. In order to manage PM in the entire city and on roads, it is necessary to increase planting density and leaf area in roadside green spaces, such as buffer green spaces, so that PM can be removed within the green spaces. However, in green spaces such as neighborhood parks that are actively used by city residents, in orderto minimize damage to users due to PM, it is desirable to create green spaces with a structure that allows PM to spread to the outside rather than stagnate inside.