• Journal of the Korean earth science society
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• v.45 no.2
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• pp.111-120
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• 2024

Cloud coverage is a key factor in determining whether to proceed with observations. In the past, human judgment played an important role in weather evaluation for observations. However, the development of remote and robotic observation has diminished the role of human judgment. Moreover, it is not easy to evaluate weather conditions automatically because of the diverse cloud shapes and their rapid movement. In this paper, we present the development of a cloud monitoring program by applying a machine learning-based Python module "cloudynight" on all-sky camera images obtained at Miryang Arirang Astronomical Observatory (MAAO). The machine learning model was built by training 39,996 subregions divided from 1,212 images with altitude/azimuth angles and extracting 16 feature spaces. For our training model, the F1-score from the validation samples was 0.97, indicating good performance in identifying clouds in the all-sky image. As a result, this program calculates "Cloudiness" as the ratio of the number of total subregions to the number of subregions predicted to be covered by clouds. In the robotic observation, we set a policy that allows the telescope system to halt the observation when the "Cloudiness" exceeds 0.6 during the last 30 minutes. Following this policy, we found that there were no improper halts in the telescope system due to incorrect program decisions. We expect that robotic observation with the 0.7 m telescope at MAAO can be successfully operated using the cloud monitoring program.

• Proceedings of the KSRS Conference
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• 2006.03a
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• pp.87-90
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• 2006

인천-제주 정기여객선에 수온, 클로로필 및 탁도계 등의 센서를 설치하여 해양환경 모니터링 시스템을 구축하였으며, 여객선 항로를 따라 2001년부터 2004년까지 18회에 걸쳐 자동관측과 함께 20-30분 간격으로 30여개의 정점에서 해수를 채수하여 분석하였다. 연구의 목적은 채수된 해수를 직접 분석하여 여객선에 설치된 자동측정 센서가 신뢰성 있는 자료를 생산하는지 비교 분석하는 것과 서해 한반도 연안의 해수특성을 전체적으로 이해함으로서 계절적인 변동을 파악하는 것이다. 2001-2003년 초까지 사용된 YSI 센서는 수온, 염분, 탁도와 클로로필 농도 등을 종합적으로 측정할 수 있는 멀티센서이나, 설치하여 운용해 본 결과 정밀도에서 많은 문제점이 발생하였다. 따라서 2004년 이후 클로로필과 탁도 자동 측정을 위한 단일 센서들로 교체되었으며 이들 센서는 멀티센서 보다 좋은 결과를 보였다. 비록 자동측정 장치에 문제는 있었으나, 18회에 걸친 서해 연안의 실시간 모니터링을 통하여 해수환경의 계절별 특성을 이해할 수 있었다. 부유퇴적물의 경우, 경기만과 목포 주변의 남쪽 해안은 농도가 모든 계절에서 높게 나타났으며 특히 가을 겨울철에 가장 높은 값을 나타냈다. 클로로필의 농도도 경기만 중심지역과 남쪽 해안에서 여름과 가을철에 걸쳐 0.4 - 6.0 $mg/m^3$ 정도의 분포를 보였으나 겨울철에는 2.6 $mg/m^3$ 미만으로 나타났다.

• Journal of the Korean Association of Geographic Information Studies
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• v.22 no.4
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• pp.229-240
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• 2019

3D geo-spatial model have been widely used in the field of Civil Engineering, Medical, Computer Graphics, Urban Management and many other. Especially, the demand for high quality 3D spatial information such as precise road map construction has explosively increased, MMS and UAV techniques have been actively used to acquire them more easily and conveniently in surveying and geo-spatial field. However, in order to perform 3D modeling by integrating the two data set from MMS and UAV, its so needed an proper registration method is required to efficiently correct the difference between the raw data acquisition sensor, the point cloud data generation method, and the observation accuracy occurred when the two techniques are applied. In this study, we obtained UAV point colud data in Yeouido area as the study area in order to determine the automatic registration performance between MMS and UAV point cloud data using ICP(Iterative Closet Point) method. MMS observations was then performed in the study area by dividing 4 zones according to the level of overlap ratio and observation noise with based on UAV data. After we manually registered the MMS data to the UAV data, then compared the results which automatic registered using ICP method. In conclusion, the higher the overlap ratio and the lower the noise level, can bring the more accurate results in the automatic registration using ICP method.

• Bulletin of the Korean Space Science Society
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• 2002.10a
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• pp.38.2-38
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• 2002

• 한국지구과학회:학술대회논문집
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• 2002.02a
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• pp.43-43
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• 2002

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.447-447
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• 2022

하굿둑 실증시험 및 개방 시 하굿둑으로부터 해안지역 대수층의 지하수 내 염분침투를 예방하고 지속가능한 지하수자원 이용과 관리를 위해서 담수(freshwater)와 염수(saltwater)의 경계면 변동 및 분포를 추적하기 위해 지화학적·물리적 접근 연구는 매우 중요하다. 해안 및 하굿둑 주변지역의 담·염수 경계면 특성에 관한 조사 및 분석은 직·간접적 관측방법으로 이뤄진다. 직접 관측방법에는 심도별 전기전도도(Electrical condutivity, EC) 측정 방법으로 1개 정밀센서(CTD-Diver)를 와이어에 연결하여 수동으로 측정하는 방식과 자동 관측센서(CTD-Diver)를 공내 여러 관심심도에 이격거리에 따른 관측센서를 여러 개 설치하여 특정 관심심도별 연속적인 상태를 파악하는 방법이다. 간접 관측방법에는 관심심도별 또는 특정 심도의 지하수 수질을 채취하여 지화학 분석하는 방법이 있다. 직·간접적 관측방법에는 관심심도별 구간의 이격거리와의 공백과 조사시기에 대수층의 해수침투를 파악할 수 있으나 연속적 관측과 예측은 매우 어렵다. 직접적 관측방법 중 1개 정밀센서와 와이어를 이용한 특정 시·공간에 대한 연직 프로파일링 관측은 가능하나, 연속적 관측과 예측 또한 매우 어렵다. 따라서 본 연구는 물리적 방법을 기반으로, 하굿둑 인근의 담수(freshwater)와 염수(saltwater)와의 경계면 분포특성에 관한 연구는 하굿둑 실증시험 시 지하수 내 염분침투에 따른 지하수 환경 등에 대한 전반적 특성 등을 분석하였다. 하구언 일대의 지하수 내 염분침투 및 지하수 오염관리를 위해 실증실험 등 인위적인 요소와 강우, 태풍, 가뭄 등 자연적인 요소에 의해 여러 형태의 분포특성을 보이는 담수와 염수의 분포 및 혼합대의 특성에 따른 담염수의 경계면 형태별 분석을 하는데 목적을 두었다. 해수침투의 예방과 지하수 오염 방지를 위해 심도별 자동 수질측정 장치를 개발하고, 이를 이용한 염지하수의 프로파일링 감시 시스템을 제안하였다.

• KCID journal
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• v.12 no.1
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• pp.60-68
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• 2005

The purpose of this study is to develop the reservoir water monitoring system with automatic level meter. Until now, installation of water level meter for reservoir stage monitoring were not widely spread in agricultural area. This has several reason : to

• Journal of the Korean earth science society
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• v.30 no.4
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• pp.478-484
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• 2009

A web page was developed to enhance students' learning experience in studying meteorological phenomena. After collecting the meteorological elements observed with automatic weather observation system (AWS), it serve real-time meteorological information on demand. Past meteorological information as well as real-time current information can be retrieved because the web page can save and accumulate observed information in its data base. The completed web page was successfully applied in school settings in teaching students meteorology research sections of earth science. The results show that students experienced authentic and meaningful learning through the real-time meteorological information from the web page. In addition, large scale of time was required to observe meteorological phenomena and it hindered practical meteorological research in earth science classes. However, it is expected that the time limitation can be overcome by utilizing accumulated meteorological information of the web page.

• Journal of Astronomy and Space Sciences
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• v.20 no.2
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• pp.143-152
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• 2003

We constructed the photometric observation system with a small semi-automatic telescope for the systematic observations of eclipse timings of eclipsing binary stars. The system is consisted of a Paramount GT-1100s mount system, a Celestron 14 optical system, and a SBIG ST-8 camera. We developed the OBSTOOL S/W which controls the telescope and the CCD camera using the COM(Component Object Model) supported by the softwares, The Sky and MaximDL. The system performs photometric observations of a variable, comparison and check stars by moving the telescope to the chosen star separately in a similar way such as the method of photoelectric observation. We wrote pert scripts which enable a data handling pipeline for the obtained data to be classified by each of date, object and filter. And thus the images are easily preprocessed using the IRAF S/W package. Eclipse light curves of some eclipsing binary stars observed with this system are presented.

• Journal of Korean Society of Forest Science
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• v.89 no.3
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• pp.405-413
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• 2000

This study was conducted to develop an on-line monitoring system for a forest hydrological environment and its meteorological condition, such as temperature, wind direction and speed, rainfall and water level on V-notch, electrical conductivity(EC), potential of hydrogen(PH) by the motor drive sensor unit and measurement with a single-chip microprocessor as controller. These results are summarized as follows ; 1. The monitoring system consists of a signal process unit, motor drive sensor unit, radio modem unit and power supply. 2. The motor drive sensor unit protects the sensor from swift current or freezing and can constantly maintain fixed water level during measurements. 3. This monitoring system can transfer the data by radio modem. Additionally, this system can monitor hydrological conditions in real time. 4. The hardware was made of several modules with an independent CPU. They can be mounted, removed, repaired and added to. Their function can be changed and expanded. 5. These are the result of an accuracy test, the values of temperature, EC and pH measured within an error range of ${\pm}0.2^{\circ}C$, ${\pm}1{\mu}S$ and ${\pm}0.1pH$ respectively. 6. This monitoring system proved to be able to measure various factors for a forest hydrological environment in various experimental stations.