• 의료ㆍ복지 건축 : 한국의료복지건축학회 논문집
• /
• 제28권4호
• /
• pp.89-97
• /
• 2022

Purpose: Because of the recent COVID-19 pandemic, there have been many cases of using portable negative pressure unit to convert general wards into temporary negative pressure isolation wards. The purpose of this study is to analyze the indoor environment of the switching type wards. Methods: Field measurements and experiments were conducted in a medical facility. Air volume, wind speed and pressure difference were measured in non-occupant state. Dispersion tests were performed with gas and particle matter. Results: The pressure difference between the wards and the corridor was higher than -2.5 Pa in normal situation. However, in the gas and particle dispersion tests, it was found that there were concerns about the spread through leakages in low-airtight walls or ceilings. In addition, it was confirmed that the pressure imbalance in ducts through the non-sealed diffusers could cause back flow during portable unit operation. Furthermore, when there was a pressure difference between adjacent wards planned to be at same pressure level, the possibility of the spread through the leakages was found. Implications: When using portable units for making switching type wards, it is necessary to create airtight space and seal the non-operation diffusers. In case of operating the air handling unit, T.A.B must be performed to adjust the duct balancing.

• International Journal of Naval Architecture and Ocean Engineering
• /
• 제13권1호
• /
• pp.599-616
• /
• 2021

The semi-submersible with three circular columns is an original concept of efficient multifunctional platform, which can be used for marginal oil, gas field, and Floater of Wind Turbines (FOWT). However, under certain flow conditions, especially in uniform current with specific velocities, the eddies will alternatively form and drop behind columns, resulting in the fluctuating lift force and drag force. Consequently, the semi-submersible will subject to the Flow-Induced Motions (FIM). Based on the Detached Eddy Simulation (DES) method, the numerical studies were carried out to understand the FIM characteristics of the three-column semi-submersible at two different parameters, i.e., current incidences (0°, 30°, and 60°-incidences) and reduced velocities (4 ≤ U_r ≤ 14). The results indicate that the lock-in range of 6 ≤ U_r ≤ 10 for the transverse motions is presented, and the largest transverse non-dimensional nominal amplitude is observed at 60°-incidence, with a value of A_y/D = 0:481. The largest yaw amplitude A_yaw is around 3.0° at 0°-incidence in the range of 8 ≤ U_r ≤ 12. The motion magnitude is basically the same as that of a four-column semi-submersible. However, smaller responses are presented compared to those of the three-column systems revealing the mitigation effect of the pontoon on FIM.

• Journal of Astronomy and Space Sciences
• /
• 제40권4호
• /
• pp.199-215
• /
• 2023

The Korea Pathfinder Lunar Orbiter (KPLO), the first South Korea lunar exploration probe, successfully arrived at the Moon on December, 2022 (UTC), following a 4.5-month ballistic lunar transfer (BLT) trajectory. Since the launch (4 August, 2022), the KPLO magnetometer (KMAG) has carried out various observations during the trans-lunar cruise phase and a 100 km altitude lunar polar orbit. KMAG consists of three fluxgate magnetometers capable of measuring magnetic fields within a ± 1,000 nT range with a resolution of 0.2 nT. The sampling rate is 10 Hz. During the originally planned lifetime of one year, KMAG has been operating successfully while performing observations of lunar crustal magnetic fields, magnetic fields induced in the lunar interior, and various solar wind events. The calibration and offset processes were performed during the TLC phase. In addition, reliabilities of the KMAG lunar magnetic field observations have been verified by comparing them with the surface vector mapping (SVM) data. If the KPLO's mission orbit during the extended mission phase is close enough to the lunar surface, KMAG will contribute to updating the lunar surface magnetic field map and will provide insights into the lunar interior structure and lunar space environment.

• 대기
• /
• 제34권2호
• /
• pp.83-95
• /
• 2024

Atmospheric rivers (ARs) are closely related to local precipitation which can be both beneficial and destructive. Although several studies have evaluated their predictability, there is a lack of studies on East Asian ARs. This study evaluates the prediction skill of East Asian ARs in the Korean Integrated Model (KIM) for 2020~2022 summer. The spatial distribution of AR frequency in KIM is qualitatively similar to the observation but overestimated. In particular, the model errors greatly increase along the boundary of the western North Pacific subtropical high as the forecast lead time increases. When the prediction skills are quantitatively verified by computing the Anomaly Correlation Coefficient and Mean Square Skill Score, the useful prediction skill of daily AR around the Korean Peninsula is found up to 5 days. Such prediction limit is primarily set by the wind field errors with a minor contribution of moisture distribution errors. This result suggests that the improved prediction of atmospheric circulation field can improve the prediction of East Asian summer ARs and the associated precipitation.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 1999년도 춘계학술대회 논문집
• /
• pp.183-192
• /
• 1999

The derivative equation measured of a MV=Kp8{(EVn-EVn-1)+Ki/S/1* EVn+(Kd/s)*(2PVn-1-{PVn-PVn-1)}(원문이미지참조) is used on the machine apparatus of industrial field, but this par doesn\`t able to educate now, because we didn\`t have the implementation device of PID module, so the principle implementation system of the PID Module is manufactured and developed. Through this system, the implementation system of PID Module is practiced with that the SV and the set of P, I, D is set on the derivative equation measured of PID. A things to be known of this experiment result is flow. 1)PID module is known that had to be used with the module of A/D and D/A. 2) In process of PV is approached to the SV to follow Kp, Ti and Td to cause a constant of set value on the MVp=Kp*EV, Mv=Ki/1 EVdt, MVd+tDBT/D EV(원문이미지참조) the variable rate of E and Kp, Td, Ti in that table 1 is analysed, is same as flow. ①If Kp is high, PV is near fast to the SV, but Kp is small, PV is near slowly to the SV. ②If Ki is shot, PV is close fast to the SV, but Ti is high, PV is close slowly to the SV ③If Td is high, the variable rate of E press hardly when because it doesn\`t increase, but Td is small, the variable rate of E press not hardly, upper with 1),2), PID module is supposed that be able to do the A/S and an implementation of that apparatus, and getting a success of aim that an engineer want, on control of temperature, tension, velocity, amount of flow, power of wind end so on, to get the principle of automatic implementation in industrial field with cooperation of A/D and D/A module.

• 한국해안·해양공학회논문집
• /
• 제32권4호
• /
• pp.273-283
• /
• 2020

2012년 서해에 내습한 태풍 볼라벤에 의해 발생한 폭풍해일과 파랑을 일본 기상청의 JMA-MSM 기상 예보 자료를 이용하여 수치모의하고, 계산된 해일고를 전국 해안의 항만에서 관측된 폭풍해일 자료와 비교하였다. 폭풍해일과 동시에 발생하는 파랑에 대해서는 해양조사원과 기상청에서 운영하는 해상 파고부이 자료와 비교하여 검증하였다. 기상자료에 따른 폭풍해일과 파랑의 특성을 파악하기 위해 미국 합동태풍경보센터인 JTWC에서 제공하는 best track을 이용하여 생성된 기압장과 바람장을 이용한 수치모의를 수행하고 비교하여 분석하였다. JMA-MSM 기상장은 지형과 선행 배경 기상장이 잘 반영되어 태풍 통과 전후의 전 기간에 걸쳐 파랑과 폭풍해일을 비교적 잘 재현한 반면, JTWC best track을 이용하여 생성된 기상장은 태풍 영향 구역이 협소하여 파랑과 해일고의 시간적 변화 등 전반적인 추세를 반영하지 못하는 등 한계가 있었다. 이 연구를 통하여 폭풍해일과 파랑을 추산하기 위해 신뢰도 높은 기상장이 필수적임을 알 수 있었다.

• 한국해안·해양공학회논문집
• /
• 제32권5호
• /
• pp.351-362
• /
• 2020

2003년 남해안에 내습한 태풍 매미에 의해 발생한 폭풍해일과 파랑을 JMA-MSM 예보기상자료, NCEP-CFSR 재분석 기상자료, ECMWF-ERA5 재분석 기상자료, JTWC의 최적경로를 이용한 기상자료를 이용하여 수치모의하고, 계산된 해일고를 전국 해안의 항만에서 관측된 폭풍해일 시계열 자료와 비교하였다. 폭풍해일과 동시에 발생하는 파랑에 대해서는 계산된 유의파고를 관측 자료와 비교하였다. 이 비교를 통해 태풍 매미에 대한 각종 기상장의 신뢰도를 평가하였다. 그 결과 JMA-MSM 기상자료가 가장 신뢰도가 높았고, JTWC의 최적경로를 이용한 기상자료도 상당히 우수하게 나타났다. ECMWF-ERA5 기상자료는 전반적으로 해일고나 파고의 크기가 작게 나타났으며, NCEP-CFSR 기상자료는 태풍 매미의 특정 경우에 대해 신뢰도가 가장 낮게 나타났다. 이 연구를 통하여 폭풍해일과 파랑을 추산하기 위해 신뢰도 높은 기상장이 필수적임을 알 수 있었다.

• Animal cells and systems
• /
• 제3권2호
• /
• pp.161-165
• /
• 1999

Nephila clavata, a golden orb-web spider, was studied at two different field sites with respect to web size, height, and orientation. A majority of spiders at Site 1 (a band of shrub bush) built their webs parallel or nearly parallel to the edge of the bush. Similarly, at Site 2 (near a pond), most webs were aligned with the shoreline of the pond. Among the possible determining factors for the observed patterns of web orientation, wind and light did not appear important. Instead, the movement direction of insect prey appeared largely responsible. Disproportionately more webs faced outside the bush and toward the pond than inside the bush and away from the pond at Site 1 and 2, respectively. Such trend was more apparent for larger spiders with larger webs.

• Journal of Mechanical Science and Technology
• /
• 제17권3호
• /
• pp.440-448
• /
• 2003

In the present paper, numerical simulations of buoyant plume dispersion in a neutral and stable atmospheric boundary layer have been carride out. A Lagrangian Stochastic Model (LSM) with a Non-Linear Eddy Viscosity Model (NLEVM) for turbulence is used to generate a Reynolds stress field as an input condition of dispersion simulation. A modified plume-rise equation is included in dispersion simulation in order to consider momentum effect in an initial stage of plume rise resulting in an improved prediction by comparing with the experimental data. The LSM is validated by comparing with the prediction of an Eulerian Dispersion Model (EDM) and by the measured results of vertical profiles of mean concentration in the downstream of an elevated source in an atmospheric boundary layer. The LSM predicts accurate results especially in the vicinity of the source where the EDM underestimates the peak concentration by 40% due to inherent limitations of gradient diffusion theory. As a verification study, the LSM simulation of buoyant plume dispersions under a neutral and stable atmospheric condition is compared with a wind-tunnel experiment, which shows good qualitative agreements.

• 한국태양에너지학회 논문집
• /
• 제26권2호
• /
• pp.43-51
• /
• 2006

New renewable energy information becomes one of the greatest issues all over the world because of serious environment problems and limited fossil resources. The new renewable energy source information system is treated seriously for efficient management and distribution as dealing with these energy problems. However, it is difficult to manage and utilize new renewable energy information because gathering and surveying information is progressed individually in each research field. Therefore this paper will establish ISP(Information Strategy Planning) and propose the basic management system based-on GIS to analyze new renewable energy such as solar energy, wind power, small hydro, biomass, geothermal etc. and build the integration management system. The proposed integration management system can provide spatial analysis using thematic map, data search, data import/export and interpolation about users' queries.