http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : 추민기 (검색결과 29 건)
- 무료
- 기관 내 무료
- 유료
-
MODIS 시계열 위성영상을 이용한 한라산과 지리산 구상나무 식생 변동 추세 분석
추민기,유철희,임정호,조동진,강유진,오현경,이종성 대한원격탐사학회 2023 대한원격탐사학회지 Vol.39 No.3
Korean fir (Abies koreana Wilson) is one of the most important environmental indicatortree species for assessing climate change impacts on coniferous forests in the Korean Peninsula. However, due to the nature of alpine and subalpine regions, it is difficult to conduct regular field surveysof Korean fir, which is mainly distributed in regions with altitudes greater than 1,000 m. Therefore,this study analyzed the vegetation change trend of Korean fir using regularly observed remote sensingdata. Specifically, normalized difference vegetation index (NDVI) from Moderate Resolution ImagingSpectroradiometer (MODIS), land surface temperature (LST), and precipitation data from GlobalPrecipitation Measurement (GPM) Integrated Multi-satellitE Retrievalsfor GPM from September 2003to 2020 for Hallasan and Jirisan were used to analyze vegetation changes and their association withenvironmental variables. We identified a decrease in NDVI in 2020 compared to 2003 for both sites. Based on the NDVI difference maps, areas for healthy vegetation and high mortality of Korean fir were selected. Long-term NDVI time-series analysis demonstrated that both Hallasan and Jirisan had adecrease in NDVI at the high mortality areas (Hallasan: –0.46, Jirisan: –0.43). Furthermore, whenanalyzing the long-term fluctuations of Korean fir vegetation through the Hodrick-Prescott filter-appliedNDVI, LST, and precipitation, the NDVI difference between the Korean fir healthy vegetation and highmortality sitesincreased with the increasing LST and decreasing precipitation in Hallasan. Thissuggeststhat the increase in LST and the decrease in precipitation contribute to the decline of Korean fir inHallasan. In contrast, Jirisan confirmed a long-term trend of declining NDVI in the areas of Korean firmortality but did not find a significant correlation between the changes in NDVI and environmentalvariables (LST and precipitation). Further analyses of environmental factors, such as soil moisture,insolation, and wind that have been identified to be related to Korean fir habitats in previous studiesshould be conducted. This study demonstrated the feasibility of using satellite data for long-termmonitoring of Korean fir ecosystems and investigating their changes in conjunction with environmentalconditions. Thisstudy provided the potential forsatellite-based monitoring to improve our understandingof the ecology of Korean fir.
-
전산유동가시화를 활용한 웨이퍼 이송장치의 복사열전달에 관한 연구
추민기,정지홍,손동기,고한서 한국가시화정보학회 2022 한국가시화정보학회지 Vol.20 No.3
The high heat emitted from the process module and heat jacket may cause errors in semiconductor process equipment. Barriers were designed to reduce the temperature of surface on transfer module. A designed barrier was compared and analyzed by numerical analysis using ANSYS Fluent. The average temperature of barrier and effect of radiation heat transfer were also compared through absorbed radiative heat flux of the barrier. The adoption of the barrier had an effect on the radiative heat transfer reduction of the transfer module rod. The effect of the angles of barrier from 50° to 90° on the heat transfer was investigated using the absorbed radiative heat flux with the average temperature. The angle of barrier of 50° reduced the temperature up to 9.6 %.
-
-
-
-
상변화물질과 맥동형 히트 파이프를 이용한 배터리 열 관리 시스템에 대한 수치해석적 연구
박승현,추민기,손동기,고한서 한국가시화정보학회 2024 한국가시화정보학회지 Vol.22 No.2
To effectively control heat generation resulting from advancements in fast discharging technology for electric vehicle batteries, hybrid Battery Thermal Management Systems (BTMS) are gaining attention. In this study, a BTMS combining Phase Change Material (PCM) with Oscillating Heat Pipe (OHP) was designed. During the phase change process of the PCM, the maximum battery temperature increased slowly. Additionally, due to the excellent heat transfer capability of the OHP, the PCM/OHP BTMS delayed the time when the maximum battery temperature exceeded 50 ℃ by 810 s compared to the PCM/copper fin BTMS, resulting in the maximum battery temperature that was 41.29 ℃ lower at 3600 s. Furthermore, in the section where the latent heat of the PCM had the greatest impact, the slope of the battery temperature difference was 0.0017 lower than that of the PCM/copper fin BTMS. Therefore, the PCM/OHP BTMS demonstrates its potential as a viable hybrid BTMS.
-
-
기계학습법을 이용한 동해 울릉분지의 봄과 여름 순군집생산 추정
함도식,이인희,추민기 한국해양학회 2024 바다 Vol.29 No.1
동해 남서부해역은 대마난류나 연안 용승에 의한 영양염 공급 등으로 동해 북부나 동부에 비해 일차생산력이 높은 것으로 알려져 있지만, 이 해역의 생물 펌프에 관한 연구는 제한적이다. 본 연구에서는 O2/Ar 측정으로 산출한 고해상도 순군집생산 현장 관측 결과와 기계학습 모형을 결합하여 시공간 해상도가 8일 간격, 4 km인 봄과 여름 순군집생산 시계열 자료를 추정하였다. 기계 모형의 예측과 실측의 평균 제곱근 오차는 6 mmol O2 m-2 d-1로 관측값 평균의 15%에 해당했다. 울릉분지 중앙부의 순군집생산은 3월에 49 mmol O2 m-2 d-1로 가장 높았고, 6월과 7월에 18 mmol O2 m-2 d-1로 가장 낮았다. 이 같은 계절 변화는 3He 기체교환율로 추정한 질산염 공급률이나 234Th 비평형법으로 추정한 입자유기탄소 방출률과 유사하였다. 봄과 여름의 순군집생산 추정으로 한정된 이 연구방법을 가을과 겨울로 확대하기 위해서는 아표층수의 표층 혼입에 따른 O2/Ar 순군집생산의 오차를 보정하는 연구가 필요하다. The southwestern part of the East Sea is known to have a high primary productivity compared to those in the northern and eastern parts, which is attributed to nutrients supplies either by Tsushima Warm Current or by coastal upwelling. However, research on the biological pump in this area is limited. We developed machine learning models to estimate net community production (NCP), a measure of biological pump, with high spatial and time scales of 4 km and 8 days, respectively. The models were fed with the input parameters of sea surface temperature, chlorophyll-a, mixed layer depths, and photosynthetically active radiation and trained with observed NCP derived from high resolution measurements of surface O2/Ar. The root mean square error between the predicted values by the best performing machine model and the observed NCP was 6 mmol O2 m-2 d-1, corresponding to 15% of the average of observed NCP. The NCP in the central part of the Ulleung Basin was highest in March at 49 mmol O2 m-2 d-1 and lowest in June and July at 18 mmol O2 m-2 d-1. These seasonal variations were similar to the vertical nitrate flux based on the 3He gas exchange rate and to the particulate organic carbon flux estimated by the 234Th disequilibrium method. To expand this method, which produces NCP estimate for spring and summer, to autumn and winter, it is necessary to devise a way to correct bias in NCP by the entrainment of subsurface waters during the seasons.
-
-
ScienceON
KISS연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
