• Journal of The Korean Astronomical Society
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• v.36 no.spc1
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• pp.125-133
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• 2003

New Jersey Institute of Technology (NJIT), in collaboration with the University of Hawaii (UH), is upgrading Big Bear Solar Observatory (BBSO) by replacing its principal, 65 cm aperture telescope with a modern, off-axis 1.6 m clear aperture instrument from a 1.7 m blank. The new telescope offers a significant incremental improvement in ground-based infrared and high angular resolution capabilities, and enhances our continuing program to understand photospheric magneto-convection and chromospheric dynamics. These are the drivers for what is broadly called space weather - an important problem, which impacts human technologies and life on earth. This New Solar Telescope (NST) will use the existing BBSO pedestal, pier and observatory building, which will be modified to accept the larger open telescope structure. It will be operated together with our 10 inch (for larger field-of-view vector magnetograms, Ca II K and Ha observations) and Singer-Link (full disk H$\alpha$, Ca II K and white light) synoptic telescopes. The NST optical and software control design will be similar to the existing SOLARC (UH) and the planned Advanced Technology Solar Telescope (ATST) facility led by the National Solar Observatory (NSO) - all three are off-axis designs. The NST will be available to guest observers and will continue BBSO's open data policy. The polishing of the primary will be done in partnership with the University of Arizona Mirror Lab, where their proof-of-concept for figuring 8 m pieces of 20 m nighttime telescopes will be the NST's primary mirror. We plan for the NST's first light in late 2005. This new telescope will be the largest aperture solar telescope, and the largest aperture off-axis telescope, located in one of the best observing sites. It will enable new, cutting edge science. The scientific results will be extremely important to space weather and global climate change research.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.2
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• pp.48.3-49
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• 2016

We have five different types of observation modes with regard to the Deep Ecliptic Patrol of the Southern Sky (DEEP-South); Opposition Census (OC) for targeted photometry, Sweet Spot Survey (S1) for discovery and orbit characterization of Atens and Atiras, Ecliptic Survey (S2) for asteroid family studies and comet census, NEOWISE follow-up (NW) for near simultaneous albedo measurements in the visible bands, and Target of Opportunity (TO) observation for follow-up either for unpredictable events or targets of special interests. Different exposures with such different modes result in a wide range of background noise level, the number of background stars and the mover's projected speed in each image. The Moving Object Detection Program (MODP) utilizes multiple mosaic images being taken for the same target fields at different epochs at the three KMTNet sites. MODP employs existing software packages such as SExtractor (Source-Extractor) and SCAMP (Software for Calibrating Astrometry and Photometry); SExtractor generates object catalogs, while SCAMP conducts precision astrometric calibration, then MODP determines if a point source is moving. This package creates animated stamp images for visual inspection with MPC reports, the latter for checking whether an object is known or unknown. We evaluate the astrometric accuracy and efficiency of MODP using the year one dataset obtained from DEEP-South operations.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.2
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• pp.49.2-49.2
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• 2016

The number of discovery of asteroids with peculiar rotational states has recently increased, and hence a novel approach for lightcurve analysis is considered to be critical. In order to investigate objects such as Non-Principal Axis (NPA) rotator, we selected a NPA candidate, (5247) Kryolv as our target considering its Principal Axis Rotation (PAR) code and the visibility in early 2016. The observations of Krylov were made using Korea Microlensing Telescope Network (KMTNet) 1.6 m telescopes installed at the three southern sites with TO (Target of Opportunity) observation mode. We conducted R-band time-series photometry over a total of 51 nights from January to April 2016 with several exposures during each allocated run. The ensemble normalization photometry was employed using the AAVSO Photomtric All-Sky Survey (APASS) catalog for the standardization. We successfully confirmed its NPA spin state based on the deviation from the reduced lightcurve, and thus Krylov is recorded as the first NPA rotator of its kind in the main-belt, with its precession and rotation periods, $P{\varphi}=81.18h$ and $P_{\Psi}=67.17h$, respectively. In this paper, we present the spin direction, the 3D shape model and taxonomy of the newly confirmed NPA asteroid (5247) Krylov.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.1
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• pp.41.2-41.2
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• 2018

EL CVn-type eclipsing binaries are composed of a massive A-type main-sequence primary star and a hotter B-type secondary one. These are worthy of particular attention because the secondary stars are rare objects to be extremely low-mass white dwarf precursors (ELM proto-WD) with the mass of ${\leq}0.2M_{\odot}$, evolving to higher effective temperatures and higher surface gravities. A few of them were discovered to show multi-periodic pulsations in one or both components. We monitored one of these rare and interesting objects, J0247-25 (=1SWASP J024743.37-251549.2), at two KMTNet sites of SAAO in South Africa and SSO in Australia. The observations were performed with the KMTNet 1.6m telescopes and pre-science 4K CCD cameras during the system test run from July to November 2014. Using the photometric data obtained for a total of 23 nights, we constructed well-defined eclipsing light curves in B/V-bands and derived absolute parameters (mass and radius, etc.) of each binary component. After subtracting model eclipsing curves from the data, we detected seven frequencies with 33~53 cycles per day (c/d) and identified them to be Delta Sct-type pulsations originated from the A-type primary component. Five frequencies were turned out to be excited by rotational splitting of non-radial pressure modes, enabled us to investigate rotational properties. We could not detect any frequency higher than 100 c/d, implying that pulsation amplitudes of the proto-WD secondary decrease greatly.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.1
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• pp.75.4-76
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• 2016

DEEP-South (Deep Ecliptic patrol of the Southern sky) is one of the secondary science projects of KMTNet (Korea Microlensing Telescope Network). The objective of this project is twofold, the physical characterization and the discovery of small Solar System bodies, focused on NEOs (Near Earth objects). In order to achieve the goals, we are implementing a software package to detect and report moving objects in the $18k{\times}18k$ mosaic CCD images of KMTNet. In this paper, we present preliminary results of the moving object detection experiments using the prototype MODP (Moving Object Detection Program). We utilize multiple images that are being taken at three KMTNet sites, towards the same target fields (TFs) obtained at different epochs. This prototype package employs existing softwares such as SExtractor (Source-Extracto) and SCAMP (Software for Calibrating Astrometry and Photometry); SExtractor generates catalogs, while SCAMP conducts precision astrometric calibration, then MODP determines if a point source is moving. We evaluated the astrometric accuracy and efficiency of the current version of MODP. The plan for upgrading MODP will also be mentioned.

• Acta Via Serica
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• v.1 no.1
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• pp.69-93
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• 2016

This article compares two Iranian towers (burj) of the Saljuq period (c.1037-1194) with two Chinese Pagodas (t'a) of the Song dynasty (c.960-1279) in order to identify common cultural trends in medieval Iranian and Chinese architecture. To this end, the Iranian towers of Tuqrul in Rayy and Chihil Dukhtar in Damghan are compared with their Chinese counterparts of the Iron Pagoda in Kaifeng and the Pizhi Pagoda in Changqing. The two Iranian towers have much simpler architectural decorations compared to the splendid Song pagodas, which are decorated with statues and colorful paintings. The similarities in form, however, suggest common functions provided by the architecture. Both the Saljuq and Song towers had astronomical and military functions, position identification for travelers, and symbolic meanings, as well as their main functions as tombs. By applying comparative studies on the forms and functions of the Tuqrul and Chihil Dukhtar towers on the one hand, and the Iron and Pizhi Pagodas, on the other hand, this article aims to contribute new insights regarding common social trends shared by the medieval Iranian and Chinese and illustrated by their architecture. Extensive and distinguished publications on the general subject of art and architecture during the reign of the two dynasties under discussion already exist, as fully referenced below, but the specific comparative themes regarding the individual sites discussed here are the first in any study of this kind.

• Journal of Wetlands Research
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• v.8 no.1
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• pp.83-96
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• 2006

In this study, hydraulic flood routing is performed by 1-Di. unsteady flow model, FLDWAV on the downstream of Nakdong river. For input information, KOWACO Rainfall-Runoff Model is used and resonable boundary condition is constructed. As the result of the application about the past flood event, good agreement of comparison with observed and calculated values are show in the interesting sites, Jindong and Samrangjin. Additionally, estuary barrage's WSL evaluation procedure is enhanced to accurate calculation, and it is defined by downstream boundary condition in Nakdiong river. The new regressive equation to calculate the predicted tide value is developed by considering the astronomical tide and past observed tide value at Nakdong estuary barrage. The guideline's construction of the new application and flood forecasing system of other river basins is possible by using this studied results.

• Economic and Environmental Geology
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• v.47 no.6
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• pp.589-599
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• 2014

This study selected optimal sites in Myeongsasimni located in west coast of Korea for stratigraphic research containing extreme climate event during quaternary period by spatio-temporal analyses of changes in sedimentary environment and land use employing 1918 topographic map, 2000 digital terrain map, 1976 and 2012 air photographies. The study area shows no significant changes in topographic characteristics that hilly areas with relatively large variations in elevation are distributed over north and south part of the study area, and sand dues are developed along the coast line. Moreover, flat low lying areas are located at the back side of the sand dues. The movement of surface run off and sediment loads shows two major trends of inland direction flow from back sides of sand dunes and outland direction flow from high terrains inland, and the two flows merge into the stream located in the center of the study area. Two sink with individual area of $0.2km^2$ are observed in Yongjeong-ri and Jaryong-ri which are located in south central part and south part of the study area, respectively. In addition, sea level change simulation reveals that $3.4km^2$ and $3.64km^2$ are inundated with 3 m of sea level rise in 1918 and 2000, respectively, and it would contribute to chase sea level change records preserved in stratigraphy. The inundated areas overlaps well with sink areas where it indicates the low lying areas located in south cental and south part of the study area are identical for sediment accumulation. The areas with minimal human impact on sediment records over last 100 years are $3.51km^2$ distributed over central and south part of the study area with the land use changes of mud and rice field in 1918 to rice field in 2012. The candidate sites of $0.15km^2$ in central part and $0.09km^2$ in south part are identified for preferable locations of geologic record of extreme climate events during quaternary period based on the overlay analysis of optimal sedimentary environment and land use changes.

• Korean Journal of Heritage: History & Science
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• v.47 no.1
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• pp.66-81
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• 2014

Burnt down during the Imjin War(壬辰倭亂) of 1592, Gyeongbokgung Palace(景福宮) remained in ruins until 1865, when in the second year of King Gojong's(高宗) reign, reconstruction work began. At the time, a royal protocol(uigwe, 儀軌) for the reconstruction was not produced. Instead, the Gyeongbokgung Palace Construction Diary(Gyeongbokgung yeonggeon ilgi, 景福宮營建日記) records the reconstruction process from June to September of 1865. The contents of this diary reveal that the stone used in the construction was obtained from Ganghwa(江華), the Yeongpung field(映楓亭) just beyond Dongdaemun, and Samcheongdong(三淸洞), among other sites. In addition, selected stone remaining from the original Gyeongbokgung Palace site - such as that from the palace astronomical observatory(ganuidae, 簡儀臺) - as reused, while a number of buildings and stonework from Gyeonghuigung Palace(慶熙宮) were moved to Gyeongbokgung Palace. As a result, a number of $17^{th}$ and $18^{th}$ century stonework are currently located at Gyeongbokgung Palace. The Gyeongbokgung Palace Construction Diary contains a record indicating that the bronze dragon(靑銅龍) excavated from the lotus pond at the palace's Gyeonghoeru Pavilion(慶會樓) was created by special technician byeolganyeok(別看役) Kim Jae-su(金在洙) in 1865 for the symbolic purpose of protecting the palace from fire. The diary also reveals that among Kim Jae-su and the other special technicians(byeolganyeok) tasked with the installation and oversight of the palace stonework was Lee Se-ok(李世玉) - aid to have created the haechi statue at Gwanghwamun Gate. This indicates that there were men of court painter(hwawon, 畵員) background among the construction special technicians(byeolganyeok). Moreover, the diary records the names of the stoneworkers(seokjang, 石匠) who worked under these special technicians to actually carve the stonework. These included Jang Seong-bok(張聖福), who participated in the creation of the Geunjeongjeon Hall(勤政殿); and Kim Jin-myeong(金振明), who took part in the construction of Gwanghwamun Gate(光化門). Based on these results, it is possible to identify a number of special iconographic features of the scale-covered animal form(insuhyeong, 鱗獸形) auspicious animal statues at Gyeongbokgung Palace. These include a protruding mouth and large nose, formalized ears, and a mane along the back. Comparing these iconographic features with those found in the stonework of Joseon tombs makes it clear that these palace statues were created in the latter half of the $19^{th}$ century - the period corresponding to Gojong's palace reconstruction. This study was able to confirm that this iconography was taken up by the Gyeongbokgung Palace construction special technicians(byeolganyeok) and stoneworkers(seokjang) as they worked on tomb stonework earlier in their careers.