• Title/Summary/Keyword: Sky condition

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Detection of Yellow Sand Dust over Northeast Asia using Background Brightness Temperature Difference of Infrared Channels from MODIS (MODIS 적외채널 배경 밝기온도차를 이용한 동북아시아 황사 탐지)

  • Park, Jusun;Kim, Jae Hwan;Hong, Sung Jae
    • Atmosphere
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    • v.22 no.2
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    • pp.137-147
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    • 2012
  • The technique of Brightness Temperature Difference (BTD) between 11 and $12{\mu}m$ separates yellow sand dust from clouds according to the difference in absorptive characteristics between the channels. However, this method causes consistent false alarms in many cases, especially over the desert. In order to reduce these false alarms, we should eliminate the background noise originated from surface. We adopted the Background BTD (BBTD), which stands for surface characteristics on clear sky condition without any dust or cloud. We took an average of brightness temperatures of 11 and $12{\mu}m$ channels during the previous 15 days from a target date and then calculated BTD of averaged ones to obtain decontaminated pixels from dust. After defining the BBTD, we subtracted this index from BTD for the Yellow Sand Index (YSI). In the previous study, this method was already verified using the geostationary satellite, MTSAT. In this study, we applied this to the polar orbiting satellite, MODIS, to detect yellow sand dust over Northeast Asia. Products of yellow sand dust from OMI and MTSAT were used to verify MODIS YSI. The coefficient of determination between MODIS YSI and MTSAT YSI was 0.61, and MODIS YSI and OMI AI was also 0.61. As a result of comparing two products, significantly enhanced signals of dust aerosols were detected by removing the false alarms over the desert. Furthermore, the discontinuity between land and ocean on BTD was removed. This was even effective on the case of fall. This study illustrates that the proposed algorithm can provide the reliable distribution of dust aerosols over the desert even at night.

The Analysis of Optimal Site Condition for Photovoltaic System and Green Roof Planting through Sunlight Component Simulation of Rooftop Area (옥상공간의 태양광 자원 해석을 통한 PV 시스템 및 녹화식재에 대한 적지조건분석)

  • Kim, Tae Han;Park, Dae Keun;Kwan, Ji Young
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.16 no.4
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    • pp.27-40
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    • 2013
  • These day morden cities have serious climatic problems due to enviornmental load caused by excessive development of urbanization. As technological improvement to answer to various ecological disasters and climate changes are also called on the field of construction, inter-disciplinary studies linked to the estabilishment of sustainable energy generation systems and enviornmental control is needed in a consilient point of view. This study aims to analyse optimal site conditions for photovoltaic system and green roof planting through solar radiation simulation in a integrated perspective. In so doing, it seeks to proffer basic study for developing a sound use of roof area that is sustainable in environmental and resources aspects. A computer simulation showed that, in the case of total seasonal solar radiation, summer season resulted 312.5kWh in 35% of total annual solar radiation. This season indicated the lowest radiation rate of the year for direct sunlight in 45.8% of total seasonal solar radiation. Due to such solar radiation simulation, at the largest optimal planting area, Glechoma hederacea var. longituba secured $719.16m^2$ of gross roof area.

The Chair-of-Chair-Guided Floor Control for Sharing Objects without Collision in a Multi-Session Collaborative Authoring Environment (다중세션 공동저작 환경에서의 충돌 없는 객체 공유를 위한 대표의장 방식의 플로어 제어)

  • Shin, Seong-Woon;Oh, Sam-Kweon
    • The KIPS Transactions:PartA
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    • v.12A no.5 s.95
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    • pp.433-440
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    • 2005
  • The sharing of objects for authoring frequently occurs among participating users in a cooperative authoring system where many users can collaborate. Floor control is therefore needed not only for minimizing the race condition during object accesses but also for ensuring the exclusive use of objects. h floor is a temporary access right that is given to a participating user who wants to use a shared object. Although the floor control methods for a single session environment can be found in various literature, those methods for a multi-session environment can hardly be found. In a multi-session environment, an object can be shared by multiple sessions. As a solution to the problems due to object sharing in such an environment, this paper presents a floor control method based on the chair-of-chair guidance. This method is an extension of those based on traditional chair guidance; the chair-of-chair elected among session chairs exists in this method.

Infrared Spectral Signatures of Dust by Ground-based FT-IR and Space-borne AIRS (지상 및 위성 고분해 적외스펙트럼 센서에서 관측된 황사 특성)

  • Lee, Byung-Il;Sohn, Eun-Ha;Ou, Mi-Lim;Kim, Yoon-Jae
    • Atmosphere
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    • v.19 no.4
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    • pp.319-329
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    • 2009
  • The intensive dust observation experiment has been performed at Korea Global Atmosphere Watch Center (KGAW) in Anmyeon, Korea during each spring season from 2007 to 2009. Downward and upward hyper-spectral spectrums over the dust condition were measured to understand the hyper-spectral properties of Asian dust using both ground-based Fourier Transform Infrared Spectroscopy (FT-IR) and space-borne AIRS/Aqua. To understand the impact of the Asian dust, a Line-by-Line radiative transfer model runs to calculate the high resolution infrared spectrum over the wave number range of $500-500cm^{-1}$. Furthermore, the radiosonde, a $PM_{10}$ Sampler, a Micro Pulse Lidar (MPL), and an Aerodynamic Particle Sizer (APS) are used to understand the vertical profile of temperature and humidity and the properties of Asian dust like concentration, altitude of dust layer, and size distribution. In this study, we found the Asian dust distributed from surface up to 3-4 km and volume concentration is increased at the size range between 2 and $8{\mu}m$ The observed dust spectrums are larger than the calculated clear sky spectrums by 15~60K for downward and lower by around 2~6K for upward in the wave number range of $800-1200cm^{-1}$. For the characteristics of the spectrum during the Asian dust, the downward spectrum is revealed a positive slope for $800-1000cm^{-1}$ region and negative slope over $1100-1200cm^{-1}$ region. In the upward spectrum, slopes are opposed to the downward one. It is inferred that the difference between measured and calculated spectrum is mostly due to the contribution of emission and/or absorption of the dust particles by the aerosol amount, size distribution, altitude, and composition.

A Study on Secondary School Students' Recognition on Weather Proverbs and Application to Science Teaching (일기속담에 대한 중.고등학생들의 인식과 과학수업에의 이용)

  • Kook, Dong-Sik;Lee, Cheol-Woo
    • Journal of the Korean Society of Earth Science Education
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    • v.1 no.1
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    • pp.85-98
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    • 2008
  • Though the investigation of the suggested references proverbs related weather were collected and considered the probability of the usage on science instruction. The results are as follows. 130 proverbs related to weather were collected through the investigation of the suggested references. Most of weather proverbs are based on the states of sky, clouds, wind, precipitation, actions of animal, states of plants and the condition of people in daily life. they were classified according to weather types, natural phenomena and seasons. According to the results of analysing the students' recognition and interests on weather proverbs, most of students heard weather proverbs in their elementary school years firstly through their parents, books, and teachers. However they have only heard a few. Also many students also tend to think weather proverbs have a scientific base because weather proverbs have been told by many people through the ancient time and correspond to their personal experiences. Students responded that weather proverbs are useful for science learning on weather and can teach heritage and wisdom. After reading the suggested weather proverbs, their interests on weather proverbs were increased more than before reading. This is one of reasons why weather proverbs can be introduced to science classes. Weather proverbs were considered related to science curriculum. The third grade has a Unit "Fine days and Cloudy days", the fifth grade, "Unit of Weather Change", the Sixth grade, "Unit of Weather Forecast" , the Ninth grade, "Unit of Water cycle and Weather Change" and the tenth grade has "Unit of Earth". So the author consider that weather proverb materials can be used so effectively to bring about interest and motive in science learning.

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Distribution of Midday Air Temperature and the Solar Irradiance Over Sloping Surfaces under Cloudless Condition (맑은 날 한낮의 사면 기온분포와 일사 수광량 간 관계)

  • Kim, Soo-Ock;Yun, Jin I.
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.15 no.4
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    • pp.291-297
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    • 2013
  • Automated weather stations were installed at 9 locations with, three different elevations, (i.e., 50m, 100m, and 300m a.s.l.) with different slope and aspect in a small watershed ($50km^2$ area). Air temperature at 1500 LST and solar radiation accumulated for 1100-1500 LST were collected from January to December 2012. Topography of the study area was defined by a $30{\times}30$ m digital elevation model (DEM) grid. Accumulated solar irradiance was calculated for each location with the spatially averaged slope and aspect of surrounding circles with 5, 10, 15, 20, 25, and 30 grid cell radii, respectively. The 1500 LST air temperature from clear sky conditions with zero cloud amount was regressed to the 1100-1500 LST solar irradiance at 9 locations. We found the highest coefficient of determination ($r^2$ = 0.544) at 25 grid cell radius and the temperature variation in this study was explained by Y = 0.8309X + 0.0438, where Y is 1500 LST temperature (in $^{\circ}C$) and X is 1100-1500 LST accumulated solar irradiance (in $MJ/m^2$).

Numerical Simulation and Comparison of Particle Dispersion and Air Quality with Domain Setting of Gwangyang Bay Area (광양만 권역의 영역 설정에 따른 입자확산 및 대기질 수치모의 비교)

  • Lee, Hyun-Mi;Lee, Hwa-Woon;Lee, Soon-Hwan
    • Journal of Korean Society for Atmospheric Environment
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    • v.26 no.6
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    • pp.591-605
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    • 2010
  • Recirculation of airmass in coastal region occurs because of the change from land to sea breeze and was shown to produce a contrary result on air quality. This study examines the numerical simulation to analyze the effect of recirculation flow in Gwangyang Bay, Korea. For this purpose two case studies are performed by the WRF-FLEXPART-CMAQ modeling system, each for a different Meso-Synoptic Index. Additionally this research make a comparative study of large domain (Domain L) and small domain (Domain S). The horizontal wind fields are simulated from WRF. Changes in the land-sea breeze have an effect on the particle dispersion modeling. The numerical simulation of air quality is carried out to investigate the recirculation of ozone. Ozone is transported to eastward under strong synoptic condition (Case_strong) because of westerly synoptic flow and this pattern can confirm in all domain. However ozone swept off by the land breeze and then transported to northward along sea breeze under conditions of clear sky and weak winds (Case_weak). In this case re-advected ozone isn't simulate in Domain S. The study found that recirculation of airmass must be concerned when numerical simulation of air quality is performed in coastal region, especially on a sunny day.

DETECTING VARIABILITY IN ASTRONOMICAL TIME SERIES DATA: APPLICATIONS OF CLUSTERING METHODS IN CLOUD COMPUTING ENVIRONMENTS

  • Shin, Min-Su;Byun, Yong-Ik;Chang, Seo-Won;Kim, Dae-Won;Kim, Myung-Jin;Lee, Dong-Wook;Ham, Jae-Gyoon;Jung, Yong-Hwan;Yoon, Jun-Weon;Kwak, Jae-Hyuck;Kim, Joo-Hyun
    • The Bulletin of The Korean Astronomical Society
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    • v.36 no.2
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    • pp.131.1-131.1
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    • 2011
  • We present applications of clustering methods to detect variability in massive astronomical time series data. Focusing on variability of bright stars, we use clustering methods to separate possible variable sources from other time series data, which include intrinsically non-variable sources and data with common systematic patterns. We already finished the analysis of the Northern Sky Variability Survey data, which include about 16 million light curves, and present candidate variable sources with their association to other data at different wavelengths. We also apply our clustering method to the light curves of bright objects in the SuperWASP Data Release 1. For the analysis of the SuperWASP data, we exploit a elastically configurable Cloud computing environments that the KISTI Supercomputing Center is deploying. Two quite different configurations are incorporated in our Cloud computing test bed. One system uses the Hadoop distributed processing with its distributed file system, using distributed processing with data locality condition. Another one adopts the Condor and the Lustre network file system. We present test results, considering performance of processing a large number of light curves, and finding clusters of variable and non-variable objects.

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Fog Sensing over the Korean Peninsula Derived from Satellite Observation of MODIS and GOES-9

  • Yoo, Jung-Moon;Jeong, Myeong-Jae;Yoo, Hye-Lim;Rhee, Ju-Eun;Hur, Young-Min;Ahn, Myoung-Hwan
    • Korean Journal of Remote Sensing
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    • v.22 no.5
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    • pp.373-377
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    • 2006
  • Seasonal threshold values for fog detection over the ten airport areas in the Korean Peninsula have been derived, using the satellite-observed data of polar-orbit (Aqua/Terra MODIS) and geostationary (GOES-9) during two years. The values are obtained from reflectance at $0.65{\mu}m\;(R_{0.65})$ and the difference in brightness temperature between $3.7{\mu}m\;and\;11{\mu}m\;(T_{3.7-11})$. In order to examine the discrepancy between the threshold values of two kinds of satellites, the following parameters have been analyzed under the condition of daytime/nighttime and fog/clear-sky, utilizing their simultaneous observations over the Seoul Metropolitan Area. The parameters are the brightness temperature at $3.7{\mu}m\;(T_{3.7})$, the temperature at $11{\mu}m\;(T_{11}$, and $T_{3.7-11}$ for day and night. The $R_{0.65}$ data are additionally included in the daytime. The GOES-9 thresholds over the seven airport areas except the Cheongju airport have revealed the accuracy of 50% in the daytime and 70% in the nighttime, based on statistical verification for the independent samples as follows; FAR, POD and CSI. However, the accuracy decreases in the foggy cases with twilight, precipitation, short persistence, or the higher cloud above fog.

An analysis of the production conditions for small-sized women's jacket products - Focusing on young contemporary brands for spring/summer 2021 - (여성복 스몰사이즈 재킷 제품 생산실태- 2021년 S/S 영컨템포러리 브랜드를 중심으로 -)

  • Lee, Yujin;Jang, Jeongah
    • The Research Journal of the Costume Culture
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    • v.29 no.6
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    • pp.849-864
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    • 2021
  • This study analyzed product conditions in terms of "size system," "clothing construction depending on fit," "details," "colors," and "prices," with an emphasis on young contemporary brands for spring/summer 2021, in order to provide basic data for the development of small-sized women's jackets. Out of 96 domestic and foreign brands, the study analyzed 254 small-sized jacket products from 23 brands that produce size-XS jackets. First, when examining the sizes for women's jackets, we found that 8 out of the 23 brands offer a size-XXS option. After conducting tree analysis to analyze the factors affecting the production of size-XXS, the study found significant results in the areas of "distinction between domestic and foreign brands" and "product price." Second, after categorizing small-sized women's jackets into 3 categories-fit-slim, basic, and straight-the study analyzed clothing construction elements depending on fit. This seasons mainly feature straight-fit's hip-line length jacket, a 4-panel pattern, and a panel without a waist dart. Third, the study, through the analysis of the colors of small-sized women's jackets, found a higher frequency of colors in the order of black (23.0%), white (13.3%), and beige tones (10.1%), with additional colors such as sky blue, rose pink, and aquamarine in production, which exhibit the senses of the seasons. Price analysis revealed that small-sized jackets constituted a price range at the mid-to-low end, as in ₩50,000-100,000 (30.3%), ₩100,000-150,000 (19.3%), and ₩150,000-200,000 (11.8%).