• Journal of Environmental Science International
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• v.14 no.3
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• pp.311-325
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• 2005

Elements of atmospheric environment, temperature, humidity and wind, at the compus of KNU(Kyungpook National University) were investigated by the observations. The observed data were compared with those of DWS (Daegu Weather Station). The simulations of wind field and dispersions of polluted gases were conducted by MUKLIMO under the various conditions. The results show that the atmospheric environment of KNU are suitable but the campus does not play role as a heat sink in the city. The simulations of wind field show the air flows and wind channels in the campus clearly. The exhausted gases by motor vehicles on the northside street of campus affect very much to the campus with $NW(300^{\circ})$ wind. The running cars in the campus are also pollute much on the campus with the various wind directions. The characteristics of environmental conditions, various meteorological fields, wind channels, and dispersion of exhausted gases at the campus of KNU were understood quantitatively in the study.

• Journal of Astronomy and Space Sciences
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• v.29 no.2
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• pp.97-101
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• 2012

Monitoring sunspots consistently is the most basic step required to study various aspects of solar activity. To achieve this goal, the observers must regularly calculate their own correction factor $k$ and keep it stable. Relatively recently, two observing teams in South Korea have presented interesting papers which claim that revisions that take the yearly-basis $k$ into account lead to a better agreement with the international relative sunspot number $R_i$, and that yearly $k$ apparently varies with the solar cycle. In this paper, using artificial data sets we have modeled the sunspot numbers as a superposition of random noise and a slowly varying background function, and attempted to investigate whether the variation in the correction factor is coupled with the solar cycle. Regardless of the statistical distributions of the random noise, we have found the correction factor increases as sunspot numbers increase, as claimed in the reports mentioned above. The degree of dependence of correction factor $k$ on the sunspot number is subject to the signal-to-noise ratio. Therefore, we conclude that apparent dependence of the value of the correction factor $k$ on the phase of the solar cycle is not due to a physical property, but a statistical property of the data.

• Publications of The Korean Astronomical Society
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• v.22 no.4
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• pp.169-175
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• 2007

The international cooperation project CIBER (Cosmic Infrared Background ExpeRiment) is a rocket-borne instrument, of which the scientific goal is to measure the cosmic near-infrared extra-galactic background to search for signatures of primordial galaxy formation. CIBER consists of a wide-field two-color camera, a low-resolution absolute spectrometer, and a high-resolution narrow-band imaging spectrometer. Currently, all the subsystems have been built, and the integration, testing, and calibration of the CIBER system are on process for the scheduled launch in June 2008.

• Journal of the Korean earth science society
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• v.23 no.3
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• pp.207-220
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• 2002

The purpose of this study was to verify the trends of Korean students' achievement of earth science, especially the gender differences, in recent two international comparative studies, TIMSS-R (The Third International Mathematics and Science Study-Repeat) and PISA 2000 (Programme for International Student Assessment). To achieve this purpose, the 33 earth science items in TIMSS-R and 13 earth and environmental science items in PISA 2000 were analyzed. As a result of the comparison between Korean- and international percent correct, Korean students showed especially higher achievement in close-ended items or items required 'understanding of simple information.' Korean students, in particular Korean male students, also showed higher achievement in items of data interpretation. On the other hand, Korean students, in particular Korean female students, showed relatively lower achievement in astronomy items. The serious gender differences occurred in all aspects of items, regardless of item content, item format, and performance expectations.

• Journal of Astronomy and Space Sciences
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• v.24 no.4
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• pp.275-284
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• 2007

For the application to the numerical weather prediction (NWP) in active service, it is necessary to ensure that the GPS precipitable water vapor (PWV) data has less than one hour latency and three millimeter accuracy. The comparison and the verification between the daily products from GPS measurement by using the IGS final ephemeris and the conventional meteorological observation has been done in domestic researches. In case of using IGS final ephemeris, GPS measurements can be only post processed in daily basis in three weeks after the observation. Thus this method cannot be applied to any near real-time data processing. In this paper, a GPS data processing method to produce the PWV output with three mm accuracy and one hour latency for the data assimilation in NWP has been planned. For our new data processing strategy, IGS ultra-rapid ephemeris and the sliding window technique are applied. And the results from the new strategy has been verified. The GPS measurements during the first 10 days of January, April, July and October were processed. The results from the observations at Sokcho, where the GPS and radiosonde were collocated, were compared. As the results, a data processing strategy with 0.8 mm of mean bias and 1.7 mm of standard deviation in three minutes forty-three seconds has been established.

• Publications of The Korean Astronomical Society
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• v.32 no.1
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• pp.235-237
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• 2017

The AKARI NEP Deep Field Survey is an international multiwavelength survey over $0.4deg^2$ of the sky. This is the deepest survey made by the InfraRed Camera (IRC) of the infrared astronomical satellite AKARI with 9 filters continuously covering the $2-25{\mu}m$ range, including three filters in the Spitzer gap between the IRAC and MIPS coverages. This enabled us to make sensitive MIR detection of AGN candidates at z~ 1, based on hot dust emission in the AGN torus. It is also efficient in detecting highly obscured Compton-thick AGN population. In this article, we report the first results of X-ray observations on this field. The field was covered by 15 overlapping Chandra ACIS-I observations with a total exposure of ~300 ks, detecting ${\approx}450$ X-ray sources. We utilize rest-frame stacking analysis of the MIR AGN candidates that are not detected individually. Our preliminary analysis shows a marginal detection of the rest-frame stacked Fe $k{\alpha}$ line from our strong Compton-thick candidates.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.6
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• pp.1097-1108
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• 2019

In VLBI(Very Long Baseline Interferometry), the observed data created in many observatories which are far away from each other should be collected in correlation center for data analysis. Traditionally, observed data is moved by transportation such as car or airplane. But it is replaced with data transfer over the network rapidly as the advancement of information technology, and therefore, international cooperative research is also now more widely expanding. e-KVN(electronic Korean VLBI Network) has been upgraded two times so the network interface of KVN has been evolved to the highest specification of 100GbE. During this time period, the portion of network usage for VLBI observations and experiments in KVN has been increased exponentially. In this paper, we describe KVN VLBI system and network technology for the performance upgrade and advanced status monitoring between three radio astronomy observatories and Daejeon correlation center with KREONET(Korea Research Environment Open NETwork). Furthermore, future plan of e-KVN for the implementation of wide band VLBI observation will be also briefly discussed.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.1
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• pp.64.4-65
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• 2018

We present a study of citizen science performed at Korean Minjok Leadership Academy (KMLA). The importance of citizen involvements in scientific studies has been increasing, with remarkable results and performances. For instance, the discovery of an impact scar near Jupiter's south polar region (A. Wesley, 2009) led to an international campaign of professional observations to understand the asteroidal collision responsible for the scar. Citizen science at KMLA has been and will be mainly conducted by members of the astronomical observation club 'Apple-Pie' through amateur telescopes. Members of 'Apple-Pie' are specialized in various fields related to astronomy, from planetary science to cosmology. The spectrum not only includes fields that are directly related to astronomy but also fields such as computer science and astrophotography. The scheduled construction of a new observatory will further enable students to participate in higher level projects such as planetary monitoring over long timescales and the observation and detection of solar system bodies and exoplanets. In addition, a new supervisor with expertise and research experience in galactic astronomy, planetary science, and meteorology has joined the school faculty. He will supplement students with fundamental theoretical backgrounds and essential research techniques to enhance astronomical research at KMLA. KMLA's ultimate goal is to deploy a remote-controlled observatory available to aspiring scientists around the world to create a network of citizen science system. The prime observational conditions of KMLA and the willingness of the students and faculty members will provide a competitive edge for KMLA over other similar institutes in Korea.

• Journal of Astronomy and Space Sciences
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• v.29 no.2
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• pp.181-189
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• 2012

To broaden the understanding of classical Cepheid structure, evolution and atmospheres, we have extended our continuing secret lives of Cepheids program by obtaining XMM/Chandra X-ray observations, and Hubble space telescope (HST) / cosmic origins spectrograph (COS) FUV-UV spectra of the bright, nearby Cepheids Polaris, ${\delta}$ Cep and ${\beta}$ Dor. Previous studies made with the international ultraviolet explorer (IUE) showed a limited number of UV emission lines in Cepheids. The well-known problem presented by scattered light contamination in IUE spectra for bright stars, along with the excellent sensitivity & resolution combination offered by HST/COS, motivated this study, and the spectra obtained were much more rich and complex than we had ever anticipated. Numerous emission lines, indicating $10^4$ K up to ${\sim}3{\times}10^5$ K plasmas, have been observed, showing Cepheids to have complex, dynamic outer atmospheres that also vary with the photospheric pulsation period. The FUV line emissions peak in the phase range ${\varphi}{\approx}0.8-1.0$ and vary by factors as large as $10{\times}$. A more complete picture of Cepheid outer atmospheres is accomplished when the HST/COS results are combined with X-ray observations that we have obtained of the same stars with XMM-Newton & Chandra. The Cepheids detected to date have X-ray luminosities of log $L_X{\approx}28.5-29.1$ ergs/sec, and plasma temperatures in the $2-8{\times}106$ K range. Given the phase-timing of the enhanced emissions, the most plausible explanation is the formation of a pulsation-induced shocks that excite (and heat) the atmospheric plasmas surrounding the photosphere. A pulsation-driven ${\alpha}^2$ equivalent dynamo mechanism is also a viable and interesting alternative. However, the tight phase-space of enhanced emission (peaking near 0.8-1.0 ${\varphi}$) favor the shock heating mechanism hypothesis.

• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.55.3-56
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• 2020

유구한 전통을 배경으로 우리나라는 유네스코 세계기록유산을 세계 4위, 아시아 1위로 등재하여 기록물의 가치를 국제적으로 인정받고 있다. 이제는 세계 기록유산 16건이라는 등재 수량을 넘어, 활용도 증진을 통한 명실상부 질적 차원의 우수 세계 기록유산 보유국가로 성장해야 할 시기를 맞고 있다. 이러한 측면에서 기록유산의보편적 접근과 활용의 증진을 목적으로 하는 국제기록유산센터(ICDH, International Centre for Documentary Heritage)의 2019년 청주시 유치는 시사하는 바가 크다. 또 정부가 세계 기록유산의 다양한 활용 제고를 위한 지자체 협업 사업을 지원하기 시작한 것도 유의할만하다. 그러나 한국 천문학 분야에서는 세계 기록유산이 한 건도 지정되지 않아 우리나라의 우수한 과학적 성취가 담긴 사료들은 알려지지 않고 있으며, 체계적인 관리·보존도 미비한 상태다. 이에 이 연구는 한국 천문학 기록자원의 세계 기록유산 발굴과 등재 및 등재 이후 활용 증진을 위한 아웃리치 서비스의 방법론을 제언하는 데 목적을 가지며 다음 기획론을 제시하고자 한다. 먼저 한국 천문학 기록자원의 세계 기록유산 발굴을 위하여 유네스코의 등재평가기준과 참고할만한 등재과정의 선행사례를 분석한다. 다음으로, 등재 이후 정·관·학 협업의 체계적 관리보존과 공유체계를수립하는 방안을 모색하고자 한다. 이를 위하여 소장처와협업체간 분쟁의 소지가 될 수 있는 저작권 등 위험 요소와 참고할만한 국내외 협업의 선진사례를 분석한다. 마지막으로 한국 천문학계의 요구와 현실에 부합하는 기록학적방법론을 분석하여 한국 천문학 분야 세계 기록유산의 아웃리치서비스 방안을 제언하고자 한다. 이 연구는 천문학 분야에서 망실·훼손될 수 있는 기록 자원을 발굴하는 계기를 세계 기록유산에서 찾아, 천문학계에 새로운 연구의 장(場)을 창출하는 선순환을 도모했다는 점에서 의의가 있다. 그러나 선험적 기획이므로 과정상 발생할 수 있는 변수의 대처 방안과 유의성 분석 등 연구 결과 검증에는 한계가 있다. 향후 한국 천문학과의 협업으로 세계 기록유산과 관련한 사료 발굴과 가치 고증 등 학술적 이론 검증을 이어나가 다양한 학제 간 연구로 심화하길 기대한다.