• Korean Journal of Heritage: History & Science
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• v.45 no.4
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• pp.92-103
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• 2012

The Cheomsungdae was built in the Silla dynasty during the reign of queen Seondeok. It has a round cylindrical structure with a flowing curved fa ade. The identity of the Cheomsungdae has not been revealed since there is not much historical evidence or documents about the building. This study is trying to investigate the building technique and method from the technical point of view of the past when it was constructed. There have been much work and studies done for the Cheomsungdae, but not much were focusing on the technical aspects of the building. In addition there are many questions and doubts about the hypothesis of the building technique of Cheomsungdae since there aren't any remaining documents or historical evidence supporting it. Among many questions, we think that the discussion on falsework technique is not considering traditional construction method of the Dujabee (a traditional construction technique using various tools and equipment for the stability of the building) technique. Therefore, it is hard to identify them as reliable historical facts. As the result of the study, we want to provide the basic data on the construction techniques of Korean traditional architecture and broaden the study scope of technical history by narrowing the errors. The study could be summarized into three points. 1. The historical architecture Cheomseongdae was constructed by using traditional crane techniques such as a Noklo (pulley ladder). Cheomseongdae was re-evaluated as a high level technology for the history of architecture. 2. The benchmark method on Cheomseongdae construction has been applied with a precise scientific method based on the geometrical principals using the central axis. 3. In terms of the history of Korean traditional architecture technology, as there aren't many studies done we proposed various basic data for the traditional crane techniques and criteria of Korean traditional architecture technology. We could expect various and active studies for the technical approach of the history of architecture.

• Journal of Astronomy and Space Sciences
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• v.22 no.1
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• pp.1-12
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• 2005

The Korean VLBI Network (KVN) will open a new field of research in astronomy, geodesy and earth science using the newest three Elm radio telescopes. This will expand our ability to look at the Universe in the millimeter regime. Imaging capability of radio interferometry is highly dependent upon the antenna configuration, source size, declination and the shape of target. In this paper, imaging simulations are carried out with the KVN system configuration. Five test images were used which were a point source, multi-point sources, a uniform sphere with two different sizes compared to the synthesis beam of the KVN and a Very Large Array (VLA) image of Cygnus A. The declination for the full time simulation was set as +60 degrees and the observation time range was -6 to +6 hours around transit. Simulations have been done at 22GHz, one of the KVN observation frequency. All these simulations and data reductions have been run with the Astronomical Image Processing System (AIPS) software package. As the KVN array has a resolution of about 6 mas (milli arcsecond) at 220Hz, in case of model source being approximately the beam size or smaller, the ratio of peak intensity over RMS shows about 10000:1 and 5000:1. The other case in which model source is larger than the beam size, this ratio shows very low range of about 115:1 and 34:1. This is due to the lack of short baselines and the small number of antenna. We compare the coordinates of the model images with those of the cleaned images. The result shows mostly perfect correspondence except in the case of the 12mas uniform sphere. Therefore, the main astronomical targets for the KVN will be the compact sources and the KVN will have an excellent performance in the astrometry for these sources.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.2
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• pp.73.4-74
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• 2021

한국천문연구원은 2017년 제1차 구술채록사업에 이어 2020년 제2차 사업을 진행하면서 최초로 원외 원로에 대한 구술채록을 시도하였다. 국가 대표 천문연구의 산실로서 연구원 존재 의의를 확립하기 위하여 원내 원로에 국한되었던 구술자 대상을 확장한 것이다. 그 첫 외부 구술 대상자로 방득룡 전임 노스웨스턴 천문학과 교수를 선정하여 2020년 7월부터 준비단계에 들어갔다. 방득룡 전(前)교수가 첫 번째 한국천문연구원 원외 인사 구술자로 선정된 이유는, 그가 우리나라 천문대1호 망원경 구매 선정에 개입한 서신(1972년)이 자료로 남아있었기 때문이다. 한국천문연구원에서 2017년에 수행한 제1차 구술채록사업에서 구술자로 참여한 오병렬 한국천문연구원 원로가 기증한 사료들은 대부분 연구원 태동기 국립천문대 구축과 망원경 구매 관련 자료였으며 이 가운데 1972년 당시 과학기술처 김선길 진흥국장에게 Boller and Chivesns(사(社))의 반사경을 추천한 방득룡 전(前)교수의 서신은 한국 천문학 발전사에서 중요한 사료였다. 연구진은 이 자료를 시작으로, 방득룡 전(前)교수의 생존 여부와 문서고의 공기록물들에서 그의 흔적을 찾아가기 시작했다. 놀랍게도 그는 실제 세계와 한국천문연구원 문서고 깊숙이 기록물들 모두에서 상존하고 있었다. 1927년생인 방득룡 전(前)교수, Dr. John D. R.은 미국 플로리다 한 실버타운에서 건강한 정신으로 생존하여 있었고 연구진의 인터뷰에 흔쾌히 응했다. 2020년 9월 16일에 한국천문연구원 본원 세종홀 2층 회의실에서 영상통신회의로 그와의 구술인터뷰가 진행되었다. 이 구술인터뷰는 원외 인사가 대상이란 점 외에도 방법적으로는 전형적인 대면 방식이 아닌 영상 인터뷰였다는 점에서 코로나 시대의 대안이 되는 실험적 시도였다. 현대 한국천문학 발전사의 재조명 측면에서도 의미가 있었다. 1960년대 초반부터 1992년 정년퇴임까지 30년을 미국 유수 대학교 천문학과 교수로 재직하며 활발한 활동을 해 온 한국계 천문학자가 우리나라 최초 반사망원경 구매 선정에 적극 개입하였던 역사는, 공문서 자료들과 서신 사료들에 이어 그의 육성으로 나머지 의구심의 간극이 채워졌다. 또 구술자 개인이 주관적으로 중요하다고 여기는 '기억'이 중요한 아카이빙 콘텐츠 확장의 단초가 될 수 있다는 것을 보여줌으로써 구술사 연구에 있어서도 중요한 관점을 주었다. 애초 연구진이 방득룡 전(前)교수의 공식 기록에서 아카이빙의 큰 줄기로 잡았던 것은 1948년 도미, 1957년 위스콘신 대학교 천문학 박사학위 취득, 1962년부터 노스웨스턴 대학(일리노이주 에반스턴)의 천문학 교수진, 1992년 은퇴로 이어진 생애였다. 그러나 그와의 구술 준비 서신 왕래와 구술을 통하여 알게 된 그가 인생에서 중요시 여겼던 지점은, 1948년 도미 무렵 한국의 전쟁 전 상황과 당시 비슷한 시기에 유학한 한국 천문학자들의 동태, 그리고 1957년부터 1962년까지 프린스턴 대학교에서 M. Schwarzschild 교수와 L. Spitzer 교수를 보조하며 Stratoscope Project를 연구하였던 경험이었다. 기록학적 의미에서도, 전자를 통해서 그와 함께 동시대 한국 천문학을 이끌었던 인재들의 맥락정보를 얻을 수 있었으며, 후자를 통해서는 세계 천문학사에 큰 영향을 미친 석학에 대한 아카이브 정보와의 연계 지점과 방득룡 전(前)교수의 연구 근원을 찾을 수 있었다. 이들은 추후 방득룡 콘텐츠 서비스 시에 AIP, NASM, Lyman Spitzer 콘텐츠, 평양천문대, 화천조경천문대, 서울대와 연세대, 그리고 한국천문연구원까지 연계되어 전 세계 폭넓은 이용자들의 유입을 유도할 수 있는 검색 도구가 될 수 있다. 이번 방득룡 구술사 연구에서 구술자 개인의 주관적인 소회가 공식 기록이 다가갈 수 없는 역사적 실체에 일정 부분 가까울 수 있다는 것, 그리고 이를 통하여 개인의 역사는 공동체의 역사로 확장될 수 있다는 사실을 발견할 수 있었다. 또 연구진은 방득룡 전(前)교수의 회상을 통하여 구술자 개인의 시각으로 한국과 미국 천문학계의 공동체 역사를 재조명할 수 있었고, 이것을 아카이브 콘텐츠 확장 서비스에 반영할 수 있다는 기대를 가지게 되었다. 무엇보다 이 연구를 통하여 다양한 주제의 아카이브로 연동될 수 있는 주제어와 검색도구를 구술자 개인의 회상으로부터 유효하게 도출할 수 있다는 것을 확인하였다. 그리고 향후 한국천문 구술아카이브의 확장을 통하여 보다 다양한 활용과 연구 재활용의 선순환이 가능하다는 것도 알 수 있었다. 이는 최근 기록학계에서 대두되고 있는 LOD(Linked Open Data)의 방향성과도 흡사하여 한국천문학 구술사연구의 차세대 통합형 기록관리의 미래모형을 기대케 하는 대목이다.

• Journal of the Korean earth science society
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• v.39 no.2
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• pp.193-207
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• 2018

The purpose of this study was to analyze trends in conceptual change research in the field of Earth Science education conducted in Korea and to provide them as basic data of future concept change research. The trends of conceptual change research were analyzed in terms of keywords, year of publication, source of research, purpose of research, subject, area of research, and research method. This study was carried out on a total of 126 conceptual change papers of Earth Science education published from 1989 to July 2017. This study showed the following conclusions: First, the conceptual change research papers used more the term 'conceptual change' than 'misconceptions' and 'preconceptions'. Second, the conceptual change paper has achieved a large amount of growth in the 2000s. Third, conceptual change research tended to proceed to the subject of master's dissertation. Fourth, there were a lot of researches to find out the misconceptions and change them into the right concept, the conceptual change paper used free response test for misconceptions, and cognitive conflict instruction model and CAI (Computer Assisted Instruction) teaching strategy for misconceptions. Fifth, elementary school students were studied the most. Sixth, the study of conceptual changes in the field of Earth Science was high in the astronomical and atmospheric areas. Finally, although quantitative analysis methods were used in the early days of research, in the 2010s, qualitative analysis methods were widely used. In this paper, we proposed research on conceptual change for pre- and in-service teachers, expansion of research on conceptual changes in various fields such as geology, oceanography, atmosphere in Earth Science, investigation of causes of misconception in Earth Science and research on individual's affective factors, and so on.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.5
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• pp.455-461
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• 2017

The Hebei Spirit oil spill incident occurred in December 7, 2007 and caused approximately $12,547k{\ell}$ of crude oil spillage along 370km off the west coast of Korea. Due to the astronomical and irrecoverable damage to the marine ecosystems and the overall living standards of the residents, the oil spill incident has been notoriously named as the "worst oil spill incident" occurred in Korea. Nevertheless, though almost a decade has passed since the tragic incident in Korea, it appears that compensation and recovery efforts seem not close to satisfaction and the local residents are still struggling with various negative impacts incurred by the incident because of critical cleavage among the interests of the relevant parties to the incident. In this paper, the analysis of Hebei Spirit oil spill incident regarding two aspects was carried out; First, meticulously analyze the practical and statistical data of the incident to precisely examine the fundamental causes for its occurrence to further prevent the reoccurrence of such disastrous incident; and the second, comprehensively inspect reasons for the protracted and inefficient damage recovery and victim-oriented compensation. To be specific, this study observed the levels of compensation against damages from the incident, and the adequacy of it in terms of ultimately and inclusively addressing financial, social and ecological aspects based primarily upon the legal verdicts, and statistical and empirical surveys.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.5
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• pp.531-541
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• 2020

In this study, a computed tide of a real tide was introduced to improve the numerical solutions for tides and tidal flow simulations. The real tide was defined considering the nodal modulation amplitude, phase correction factor, astronomical argument, and tidal harmonic constants of all the constituents. The numerical simulation was performed using the real tide parameters for the west-south coastal waters of Korea, where the observation data for tides, tidal currents, waves, and winds over two seasons exist. The tidal flow simulation of the real tide was simulated successfully. The correlation coefficient between the observed and calculated values was 1.0, which indicated both accurate amplitude and phase. The U- and V-components of the tidal current obtained for the real tide had average valid correlations of 0.83 and 0.936, respectively. The speed error for the residual current was 0.006 m/s on the average, which indicated an insignificant difference, and the directional behavior of the residual current was very similar. In addition, the velocity error was attributed to various weather effects, such as high waves and wind storms. Therefore, this model is expected to improve current solutions provided that weathering forces, such as waves and winds, are considered.

• Journal of the Korean earth science society
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• v.30 no.3
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• pp.344-353
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• 2009

By measuring the brightness of night sky, we have investigated light pollution around the observatory in the College of Education, Seoul National University. As a result of measuring the extinction coefficient and photometric constants by standardization, in January 28, 2009, the extinction coefficient found to be $k_B$=0.359 and photometric constant was $C_B$=4.397. In March 27, 2009, extinction coefficients were $k_B$=0.896 and $k_V$=0.725, and photometric constants were $C_B$=6.235 and $C_V$=6.027. Brightness of the night sky was measured from east, west, south, and north each by altitude of $20^{\circ}$, $40^{\circ}$, $60^{\circ}$, $75^{\circ}$ and $90^{\circ}$. Data reduction and analysis was based on IRAF. Seeings for the each day of observation were 5.1 and 5.7 arcseconds in January 28 and March 27, respectively. Night sky spanned the magnitude range of $16{\leq}m_V$, $m_B{\leq}18$ We found that the brightness of night sky located at downtown was twice to four times brighter. On these observational conditions, limiting magnitude within 40cm-telescope becomes 11-13 magnitudes. Compared with Jan 28 and Mar 27, night sky brightness of January is 1 magnitude fainter than that of March in B filter.

• Korean Journal of Heritage: History & Science
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• v.52 no.4
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• pp.264-271
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• 2019

Cheomseongdae in Gyeongju, known as an astronomical observatory, is a cultural monument with great historical, academic, and artistic value, as its unique shape is preserved well in its original form. The outer structure, ground stability, and seismic reliability of Cheomseongdae have been assessed by numerous researchers through various scientific methods, but research on the underground structure has been insufficient. This paper contains detailed models of the underground structure of Cheomseongdae interpreted in 2D and 3D images based on the data acquired through GPR surveys conducted of features in and around the base of Cheomseongdae. As a result, the existence of twelve small features arranged in a circle, although only about half of them remain, was confirmed at a depth of 0.4 - 0.6m. Furthermore, a structure three bays long (north-south direction) and four bays wide (east-west direction) was detected beneath Cheomseongdae at the depth of 0.7 - 1.0m. Other than 2 layers of foundations as is known, a square structure with the dimensions of 7m × 7m is situated at a depth of 0.6m, directly under Cheomseongdae, and what is reading that is expected to be the foundation structure of Cheomseongdae was detected and confirmed. This foundation structure is circular with a diameter in the east-west direction of 11m and in the north-south direction of 12m. The northern, western, and eastern edges of this foundation structure are about 1m away from the foundation of Cheomseongdae, whereas the the south side extends to about 5m wide.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.23 no.4
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• pp.313-325
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• 2011

Finite element grid system using h-refinement on the Yellow Sea was constructed based on previous study (Suh, 1999b) from 14 K to 210 K and special attention was concentrated on refining the coastal zone. In grid generation, depth change between adjacent points and non-dimensional tidal wave length ratio were considered. As a result approximately a quarter of the total nodes are located nearby 5 m of shallow area. Accurate bathymetry data using 30's and ETOPO1 with open boundary conditions of 8 major tidal constituents extracted automatically from FES2004 have been applied. In tidal simulation a 3-dimensional nonlinear harmonic model was setup and tidal amplification due to changes in vertical turbulent and bottom friction were simulated. In this study not only 8 major tidal constituents but also nonlinear shallow tides $M_4,$, $MS_4$ and long period $M_f,$, $M_{sf}$ were reproduced. It is found that implication of spatial variation of friction coefficient plays a very important role in reproduction of astronomical and shallow tides which are computed by iterative computation of nonlinear terms. Also it should be considered differently with respect to tidal periods. To understand the distribution of tidal asymmetry, amplitude ratio of $M_4/M_2$ and phase differences $2g(M_2)-g(M_4)$ were calculated. Tidal distortion ratio marks up to 0.2 on the west coast showing shallow coastal characteristics and somewhat wide range of ebb-dominances in front of Mokpo area are reproduced.

• Journal of the Korean Association of Geographic Information Studies
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• v.22 no.3
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• pp.65-81
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• 2019

The twenty-four Solar Terms are Chinese traditional astronomical divisions that describe seasonal cycles of the year. Based on the analyses of meteorological data during 1979~2018, study results showed that the temperatures of the Solar Terms had increased in general in the Korean Peninsula. In North Korea, temperature increases were observed on 21 Solar Terms, and their seasonal mean temperatures were increased by $0.87^{\circ}C$, $1.19^{\circ}C$, $1.45^{\circ}C$, and $0.64^{\circ}C$ on average in spring, summer, fall, and winter, respectively. The duration of summer has lengthened due to the temperature rise in fall, and the magnitude of temperature change was greater in summer compared to winter. As for South Korea, increases in temperature were observed on 18 Solar Terms, and the temperature changes were more pronounced in fall and winter than spring and summer. The Great Snow temperature decreased more than any other Solar Terms during the study period, and this temperature change was observed both in North and South Koreas. The Great Cold, which represents the coldest day of the year, showed a significant temperature increase of $3.08^{\circ}C$, while the Slight Heat had a marginal temperature increase of $0.29^{\circ}C$. The hottest day and the first day of frost tended to come later than the Great Heat and the Frost's Decent. By contrast, the coldest day tended to occur later than the Great Cold in the study area. On average over the entire study period, the climatic fitness of the Great Heat and the Frost's Decent was higher in North Korea, and that of the Great Cold was higher in South Korea, respectively.