• 천문학회보
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• 제38권1호
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• pp.52.1-52.1
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• 2013

We present preliminary results of the photometric variability analysis in SDSS r, i and z bands for a newly confirmed FU Orionis-type object, HBC 722. We observed HBC 722 from 2011 April to 2012 November, with Camera for Quasars in Early uNiverse (CQUEAN) attached to the 2.1m Otto Struve telescope at McDonald Observatory, USA. The rapid cadence monitoring observations (minute timescale) were conducted in chosen photometric nights during observation campaigns to get adequate number of samples for short term period analysis. As this object is in active state, temperature at the inner disk/stellar surface can be characterized by the colors between r, i and z bands. Also, It is theorized that a sudden cataclysmic accretion associated with FU Orionis-type outburst can give rise to detectable "hot spots" on the central star and rotational asymmetries in the disk instability region. Thus the periodic variabilities of three bands would trace the stellar rotation or Keplerian rotation at the instability region of the inner accretion disk. Additionally, the range of instabilities could be estimated on the assumption of a temperature distribution for the HBC 722 disk. This analysis can provide a clue for understanding enhanced disk accretion of Class II young stellar object.

• 천문학회보
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• 제39권1호
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• pp.53.2-53.2
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• 2014

IGRINS, the Immersion GRating INfrared Spectrometer, is a near-infrared wide-band high-resolution spectrograph jointly developed by the Korea Astronomy and Space Science Institute and the University of Texas at Austin. IGRINS employs three HAWAII-2RG focal plane array (FPA) detectors. The mechanical mounts for these detectors serves a critical function in the overall instrument design: Optically, they permit the only positional compensation in the otherwise "build to print" design. Thermally, they permit setting and control of the detector operating temperature independently of the cryostat bench. We present the design and fabrication of the mechanical mount as a single module. The detector mount includes the array housing, a housing for the SIDECAR ASIC, a field flattener lens holder, and a support base. The detector and ASIC housing will be kept at 65 K and the support base at 130 K. G10 supports thermally isolate the detector and ASIC housing from the support base. The field flattening lens holder attaches directly to the FPA array housing and holds the lens with a six-point kinematic mount. Fine adjustment features permit changes in axial position and in yaw and pitch angles. We optimized the structural stability and thermal characteristics of the mount design using computer-aided 3D modeling and finite element analysis. Based on the computer simulation, the designed detector mount meets the optical and thermal requirements very well.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제39권
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• pp.23.1-23.8
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• 2017

Background: The aim of this study is to validate a new three-dimensional craniofacial stereophotogrammetry imaging system (3dMDface) through comparison with manual facial surface anthropometry. The null hypothesis was that there is no difference between craniofacial measurements using anthropometry vs. the 3dMDface system. Methods: Facial images using the new 3dMDface system were taken from six randomly selected subjects, sitting in natural head position, on six separate occasions each 1 week apart, repeated twice at each sitting. Exclusion criteria were excess facial hair, facial piercings and undergoing current dentofacial treatment. 3dMDvultus software allowed facial landmarks to be marked and measurements recorded. The same measurements were taken using manual anthropometry, using soluble eyeliner to pinpoint landmarks, and sliding and spreading callipers and measuring tape to measure distances. The setting for the investigation was a dental teaching hospital and regional (secondary and tertiary care) cleft centre. The main outcome measure was comparison of the craniofacial measurements using the two aforementioned techniques. Results: The results showed good agreement between craniofacial measurements using the 3dMDface system compared with manual anthropometry. For all measurements, except chin height and labial fissure width, there was a greater variability with the manual method compared to 3D assessment. Overall, there was a significantly greater variability in manual compared with 3D assessments (p < 0.02). Conclusions: The 3dMDface system is validated for craniofacial measurements.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제39권
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• pp.4.1-4.7
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• 2017

Background: This study is a quantitative evaluation of the influence of the mentolabial angle on perceived attractiveness and threshold values of desire for surgery. Methods: The mentolabial angle of an idealized silhouette male Caucasian profile image was altered incrementally between $84^{\circ}$ and $162^{\circ}$. Images were rated on a Likert scale by pretreatment orthognathic patients (n = 75), lay people (n = 75) and clinicians (n = 35). Results: A mentolabial angle of approximately $107^{\circ}$ to $118^{\circ}$ was deemed the most attractive, with a range of up to $140^{\circ}$ deemed acceptable. Angles above or below this range were perceived as unattractive, and anything outside the range of below $98^{\circ}$ or above $162^{\circ}$ was deemed very unattractive. A deep mentolabial angle ($84^{\circ}$) or an almost flat angle ($162^{\circ}$) was deemed the least attractive. In terms of threshold values of desire for surgery, for all groups, a threshold value of ${\geq}162^{\circ}$ and ${\leq}84^{\circ}$ indicated a preference for surgery, although clinicians were least likely to suggest surgery. The clinician group was the most consistent, and for many of the images, there was some variation in agreement between clinicians and lay people as to whether surgery is required. There was even more variability in the assessments for the patient group. Conclusions: It is recommended that in orthognathic and genioplasty planning, the range of normal variability of the mentolabial angle, in terms of observer acceptance, is taken into account as well as threshold values of desire for surgery. The importance of using patients as observers in attractiveness research is stressed.

• 천문학논총
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• 제30권2호
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• pp.405-407
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• 2015

We describe a survey of quasars in the early universe, beyond z ~ 5, which is one of the main science goals of the Infrared Medium-deep Survey (IMS) conducted by the Center for the Exploration of the Origin of the Universe (CEOU). We use multi-wavelength archival data from SDSS, CFHTLS, UKIDSS, WISE, and SWIRE, which provide deep images over wide areas suitable for searching for high redshift quasars. In addition, we carried out a J-band imaging survey at the United Kingdom InfraRed Telescope with a depth of ~23 AB mag and survey area of ${\sim}120deg^2$, which makes IMS a suitable survey for finding faint, high redshift quasars at z ~ 7. In addition, for the quasar candidates at z ~ 5.5, we are conducting observations with the Camera for QUasars in EArly uNiverse (CQUEAN) on the 2.1m telescope at McDonald Observatory, which has a custom-designed filter set installed to enhance the efficiency of selecting robust quasar candidate samples in this redshift range. We used various color-color diagrams suitable for the specific redshift ranges, which can reduce contaminating sources such as M/L/T dwarfs, low redshift galaxies, and instrumental defects. The high redshift quasars we are confirming can provide us with clues to the growth of supermassive black holes since z ~ 7. By expanding the quasar sample at 5 < z < 7, the final stage of the hydrogen reionization in the intergalactic medium (IGM) can also be fully understood. Moreover, we can make useful constraints on the quasar luminosity function to study the contribution of quasars to the IGM reionization.

• Journal of Animal Science and Technology
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• 제63권5호
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• pp.1098-1113
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• 2021

Maturation process of alfalfa (Medicago sativa L.) could be prevented by the reduction of lignin content in terms of conventional breeding or transgenic technology. Alfalfa could exhibit higher leaf/stem ratio, with a concern of yield loss. The objective of this study was to compare forage yield and nutritive value of low lignin alfalfa and two reference varieties subjecting to two harvest intervals and three seeding rates. The experimental design was a randomized complete block in a split-split plot arrangement with four replicates, where harvest intervals (28-day and 35-day) were assigned to whole plots, seeding rates were subplots, and varieties were sub-subplots. The weighted mean nutritive value was applied to two production years of 2016 and 2017. Hi-Gest 360 (low lignin alfalfa) provided similar yield potential and increased nutritive value compared to two reference varieties. Over a two-year production period, alfalfa harvested at every 28-day interval provided more economic returns than those at 35-day interval. For the seeding year and first production year, five cuts made by the 28-day interval produced more yield than four cuts by the 35-day interval. Due to limited rainfall in May 2017, a sharp drop of the first cutting overturned the advantage of the five-cut system. Shorter intervals between harvests generally increased crude protein (CP) concentrations. The differences of relative feed value (RFV) between two harvest intervals tended to be great during the first and second cuttings. Overall, harvest interval had a large effect on nutritive value and a more significant effect on alfalfa dry matter yield than variety selection. Seeding rate did not affect alfalfa yield and nutritive value.

• Journal of Animal Science and Technology
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• 제63권4호
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• pp.799-814
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• 2021

Information is lacking about the effect of date of a fall cut of alfalfa (Medicago sativa L.) on dry matter yield (DMY), forage nutritive value, and stands persistence. The objective of this study was to determine the effect of timing of a fall cut on DMY, forage nutritive value and stand persistence of three alfalfa varieties: low-lignin Hi-Gest 360, Roundup Ready Tonica, and conventional Gunner in Northeastern Kansas in the United States. The field study was carried out by splitting plot in randomized complete block design with four replications. The harvesting data of different maturity stages were collected in each year from 2015 to 2018. Three cuts were harvested based on the stage of maturity, and the last (fourth) cut was done on September 15, September 30, October 15, and October 30 of each year. The persistence of the alfalfa stands was determined each fall after the last cut, and each spring after the first cut, by counting the number of live plants in a randomly placed quadrat in each plot. Alfalfa cut on September 15 and September 30 had a higher stand persistence compared to alfalfa cut on October 15 and October 30. The DMY of the first cut in 2016 was significantly higher in roundup ready than the low-lignin alfalfa variety. In the second cut, DMY was significantly higher in conventional alfalfa than the roundup ready. There were no significant differences in DMY between alfalfa varieties in the rest of seasonal cuttings in 2016 and 2017 and annual total yield in both years. In general, low lignin alfalfa variety had higher crude protein and relative feed value and lower acid detergent fiber and neutral detergent fiber contents than those in roundup ready and conventional alfalfa varieties. On average, nutritive value of alfalfa was generally affected by last cutting dates in 2017. Based on 3-year data the last cutting of alfalfa in the fall could be done by September 30-October 15 without harmful effect on DMY.

• 한국빅데이터학회지
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• 제3권2호
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• pp.35-49
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• 2018

대한민국에서 치킨집은 전 세계 맥도날드 매장 수보다 많을 정도로 자영업의 큰 비중을 차지하는 창업 업종이다. 치킨집은 꾸준히 생겨나고 있지만, 소상공인의 창업 후 폐업률은 3년 62%, 5년 71%에 육박하는 것으로 나타났다. 특히, 숙박 및 음식점의 경우 70%가 3년을, 82%가 5년을 버티지 못하는 것으로 집계되었다. 이에 본 연구는 '서울 치킨집 폐업 예측 모형'을 개발하여, 예비창업자가 개업 후보지를 선정하는 의사결정 과정에 도움을 주고자 하였다. 먼저 행정자치부 지방행정 인허가 데이터의 업소별 개 폐업 신고 일자를 중심으로 다양한 변수를 수집하였다. 이후 다양한 분류 알고리즘을 적용하고, 예측 모형의 성능을 비교하였다. 그 결과, 인공신경망(Neural Networks)이 가장 높은 정확도를 보였지만 특이도와 민감도가 불균형적이었다. 이에 비해 유연판별분석(FDA)은 인공신경망보다 정확도는 낮지만, 상대적으로 균형적인 예측 성능을 보였다.

• 천문학회보
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• 제43권2호
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• pp.38.3-38.3
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• 2018

We present the results of high-resolution near-IR spectral mapping toward the Orion KL outflow. In this study, we used the Immersion Grating Infrared Spectrometer (IGRINS) on the 2.7 m Harlan J. Smith Telescope at McDonald Observatory. IGRINS's large wavelength coverage over the H & K bands and high spectral resolving power (R ~ 45,000) allowed us to detect over 35 shock-excited ro-vibrational H2 transitions and to measure directly the gas temperature and velocity of the dense outflows. In our previous study toward the H2 peak 1 region in the Orion KL outflow, we identified 31 outflow fingers from a datacube of the H2 1-0 S(1) $2.122{\mu}m$ line and constructed a three-dimensional map of the fingers. The internal extinction (${\Delta}AV$ > 10 mag) and overall angular spread of the flow argue for an ambient medium with a high density (105 cm-3). In this presentation, we show preliminary results of additional mapping toward a remarkable chain of bows (HH 205 - HH 207) farther from the ejection center, and obtain a more clear view of the shock physics of a single isolated bullet that improves on the knowledge gained from observations of the more complex peak 1 region in our earlier study.

• Journal of Animal Science and Technology
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• 제63권2호
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• pp.305-318
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• 2021

Alfalfa (Medicago sativa L.) is an important forage legume grown in Kansas, USA and its productivity with cool-season grasses however is unknown. The objective of this study was to determine the dry matter yield (DMY) and forage nutritive value of alfalfa-grass mixtures compared to those of alfalfa and grasses grown in monoculture with and without nitrogen fertilization. Three different alfalfa varieties were planted (reduced-lignin alfalfa, Roundup Ready, and conventional alfalfa) and two kinds of cool-season grasses (smooth brome, Bromus inermis Leyss, and tall fescue, Festuca arundinacea Schreb) were planted as a monoculture or in alfalfa-grass mixtures. Nitrogen fertilizer (urea) was applied at green-up at a rate of 56 kg/ha and after the second cutting at a rate of 56 kg/ha in 2016 and 2017, respectively. and control treatments received no nitrogen. DMY was significantly higher in monoculture alfalfa and alfalfa-grass mixtures than in grass monocultures. Between alfalfa monoculture and alfalfa-grass mixtures, no significant differences in DMY were found. For all treatments, nitrogen application significantly increased DMY compared to the control. In 2016 and 2017, the low-lignin alfalfa monoculture had the lowest acid detergent fiber (ADF) and the grass monocultures had the highest ADF. In 2016 and 2017, neutral detergent fiber (NDF) in smooth bromegrass and tall fescue was higher than in other species treatments. A low-lignin alfalfa monoculture had significantly lower NDF concentration compared to alfalfa-grass mixtures. When averaged over 2016 and 2017, relative feed value (RFV) was highest in low-lignin alfalfa and lowest in the grass monocultures. In both years, nitrogen fertilizer application did not affect nutritive values.