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Development of the Near Infrared Camera System for Astronomical Application

  • Moon, Bong-Kon
    • The Bulletin of The Korean Astronomical Society
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    • v.35 no.1
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    • pp.39.2-39.2
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    • 2010
  • In this paper, I present the domestic development of near infrared camera systems for the ground telescope and the space satellite. These systems are the first infrared instruments made for astronomical observation in Korea. KASINICS (KASI Near Infrared Camera System) was developed to be installed on the 1.8m telescope of the Bohyunsan Optical Astronomy Observatory (BOAO) in Korea. KASINICS is equipped with a $512{\times}512$ InSb array enable L band observations as well as J, H, and Ks bands. The field-of-view of the array is $3.3'{\times}3.3'$ with a resolution of 0.39"/pixel. It employs an Offner relay optical system providing a cold stop to eliminate thermal background emission from the telescope structures. From the test observation, limiting magnitudes are J=17.6, H=17.5, Ks=16.1 and L(narrow)=10.0 mag at a signal-to-noise ratio of 10 in an integration time of 100 s. MIRIS (Multi-purpose InfraRed Imaging System) is the main payload of the STSAT-3 in Korea. MIRIS Space Observation Camera (SOC) covers the observation wavelength from $0.9{\mu}m$ to $2.0{\mu}m$ with a wide field of view $3.67^{\circ}{\times}3.67^{\circ}$. The PICNIC HgCdTe detector in a cold box is cooled down below 100K by a micro Stirling cooler of which cooling capacity is 220mW at 77K. MIRIS SOC adopts passive cooling technique to chill the telescope below 200K by pointing to the deep space (3K). The cooling mechanism employs a radiator, a Winston cone baffle, a thermal shield, MLI of 30 layers, and GFRP pipe support in the system. Opto-mechanical analysis was made in order to estimate and compensate possible stresses from the thermal contraction of mounting parts at cryogenic temperatures. Finite Element Analysis (FEA) of mechanical structure was also conducted to ensure safety and stability in launching environments and in orbit. MIRIS SOC will mainly perform the Galactic plane survey with narrow band filters (Pa $\alpha$ and Pa $\alpha$ continuum) and CIB (Cosmic Infrared Background) observation with wide band filters (I and H) driven by a cryogenic stepping motor.

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A Study of Galactic Molecular Clouds through Multiwavelength Observations

  • Park, Sung-Joon;Min, Kyoung-Wook;Seon, Kwang-Il;Han, Won-Yong;Lee, Dae-Hee;Edelstein, Jerry;Korpela, Eric;Sankrit, Ravi
    • The Bulletin of The Korean Astronomical Society
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    • v.35 no.1
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    • pp.68.1-68.1
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    • 2010
  • We focus on two Galactic molecular clouds that are located in wholly different environments and both are observed by FIMS instrument onboard STSAT-1. The Draco cloud is known as a translucent molecular cloud at high Galactic latitude. The FUV spectra show important ionic lines of C IV, Si IV+O IV], Si II* and Al II, indicating the existence of hot and warm interstellar gases in the region. The enhanced C IV emission inside the Draco cloud region is attributable to the turbulent mixing of the interacting cold and warm/hot media, which is supported by the detection of the O III] emission line and the $H{\alpha}$ feature in this region. The Si II* emission covers the remainder of the region outside the Draco cloud, in agreement with previous observations of Galactic halos. Additionally, the H2 fluorescent map is consistent with the morphology of the atomic neutral hydrogen and dust emission of the Draco cloud. In the Aquila Rift region near Galactic plane, FIMS observed that the FUV continuum emission from the core of the Aquila Rift suffers heavy dust extinction. The entire field is divided into three sub-regions that are known as the- "halo," "diffuse," and "star-forming" regions. The "diffuse" and "star-forming" regions show various prominent H2 fluorescent emission lines, while the "halo" region indicates the general ubiquitous characteristics of H2. The CLOUD model and the FUV line ratio are included here to investigate the physical conditions of each sub-region. Finally, the development of an infrared imaging system known as the MIRIS instrument onboard STSAT-3 is briefly introduced. It can be used in WIM studies through $Pa{\alpha}$ observations.

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Ionized Fe Objects in UWIFE survey and IGRINS

  • Kim, Yesol;Koo, Bon-Chul;Pyo, Tae-Soo
    • The Bulletin of The Korean Astronomical Society
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    • v.42 no.1
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    • pp.54.1-54.1
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    • 2017
  • The UKIRT Wide-field Infrared survey for Fe+(UWIFE) is an unbiased survey of the first Galactic quadrant, with narrow-band filter centered on $1.644{\mu}m$. This survey covers $7^{\circ}$ < l < $62^{\circ}$ and |b| < $1.5^{\circ}$, where active interaction of stars and interstellar medium is expected. With median seeing of 0.8 arcsec, 5 - sigma detection limit of 18.7 mag and surface brightness limit of $8.1{\times}10^{-20}W\;m^{-2}arcsec^{-2}$, this survey gives an opportunity to statistically study Galactic [Fe II] - emitting sources for the first time. In order to identify Ionized Fe Objects (IFOs) in survey area systematically, we conducted visual inspection and automatic detection simultaneously. Total of ~300 extended IFOs are identified, most of them are found out to be part of supernova remnants (SNRs), young stellar objects, HII regions and planetary nebulae. The majority of IFOs are new discoveries which reveal shocked structures in high-extinction region. Spatial distribution of IFOs suggest that they trace Galactic structure. As a part of spectroscopic follow-up, we observed SNR candidate IFO J183740.829-061452.41 with IGRINS (Immersion Grating Infrared Spectrograph, Yuk+2010), mounted on 2.7m Harlan Smith telescope. This unknown arc-like, 6'-long IFO is coincident with inner part of radio continuum loop G25.8+0.2, which has been known as HII region. However, interior of this radio shell is filled with diffuse soft X-ray emission, and possible association of hard X-ray pulsar / pulsar wind nebula makes the nature of the IFO unclear. The H and K-band 2D spectrum shows shock-ionized [Fe II] filaments, which is apart from photoionized HII filaments. In this presentation we present basic statistics of newly identified IFOs, as well as the follow-up study of IFO J183740.829-061452.41.

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Do Galaxy Mergers Enhance Star Formation Rate in Nearby Galaxies?

  • Lim, Gu;Im, Myungshin;Choi, Changsu;Yoon, Yongmin
    • The Bulletin of The Korean Astronomical Society
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    • v.42 no.1
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    • pp.50.1-50.1
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    • 2017
  • We present our study of the correlation between star formation rate(SFR) and merging activities of nearby galaxies(d<150Mpc). Our study uses 265 UV-selected galaxies which are not classified as AGN. The UV selection is made using the GALEX Atlas of Galaxies (Gil de Paz+07) and the updated UV catalog of nearby galaxies (Bai+15). We use deep R band optical images reaching to $1{\sigma}$ surface brightness detection limit ${\sim}27mag/arcsec^2$ to classify merger features by visual inspection. We also estimated unobscured SFR($SFR_{NUV}$) and obscured SFR($SFR_{W4}$) using Near-UV continuum and 22 micron Mid-IR luminosity respectively as a indicator of star forming activity. The fraction of galaxies with merger features in each SFR bin is obtained to see if how the fraction of galaxies with merging features($F_m$) changes as a function of SFR. As a result, for 203 late type galaxies(LTGs), we found that merger fraction increases from ~8% up to 50% with $SFR_{W4}$, while for 229 LTGs $SFR_{NUV}$ shows relatively consistent fraction(~18%) of merger fraction. For early type galaxies(ETGs), we could also find no significant correlation between $F_m$ and SFR(both $SFR_{NUV}$ and $SFR_{W4}$). This result suggests that a main driver of star forming activity of UV bright galaxies, especially for obscured late types, is mergers.

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Crack Propagation in Earth Embankment Subjected to Fault Movement (단층 운동시 댐 파괴 거동 해석)

  • 손익준
    • Proceedings of the Korean Geotechical Society Conference
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    • 1988.06c
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    • pp.3-67
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    • 1988
  • Model studies on the response of homgeneous earth embankment dams subjected to strike-slip fault movement have been penomed via centrifuge and finite element analysis. The centrifuge model tests have shown that crack development in earth embankment experiences two major patters: shear failure deep inside the embankment and tension failure near the surface. The shear rupture zone develops from the base level and propagates upward continuously in the transverse direction but allows no open leakage chnnel. The open tensile cracks develop near the surface of the embankment, but they disappear deep in the embankment. The functional relationship has been developed based on the results of the centrifuge model tests incorporating tile variables of amount of fault movement, embankment geometry, and crack propagation extent in earth des. This set of information can be used as a guide line to evaluate a "transient" safety of the duaged embankment subjected to strike-slip fault movement. The finite element analysis has supplemented the additional expluations on crack development behavior identified from the results of the centrifuge model tests. The bounding surface time-independent plasticity soil model was employed in the numerical analysis. Due to the assumption of continuum in the current version of the 3-D FEM code, the prediction of the soil structure response beyond the failure condition was not quantitatively accurate. However, the fundamental mechanism of crack development was qualitatively evaluated based on the stress analysis for the deformed soil elements of the damaged earth embankment. The tensile failure zone is identified when the minor principal stress of the deformed soil elements less than zero. The shear failure zone is identified when the stress state of the deformed soil elements is at the point where the critical state line intersects the bounding surface.g surface.

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Treatise on the Continuum of Spaces, Society of Interiors - Focused on The Continuous Rapport of Space between Architecture and The City, and Architecture and The Countryside ('연속된 공간, 내부 사회'에 관한 논고 - 건축과 도시 그리고 건축과 전원/시골의 연속적인 공간 관계를 중심으로)

  • Kim, Myungshig
    • Korean Institute of Interior Design Journal
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    • v.24 no.2
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    • pp.100-107
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    • 2015
  • The paper begins with the idea of the society of the continued rooms that building connects architectural space (building interior) and urban open space (urban interior) or countryside/rural open space (territorial interior). It gives an account of, through literature review, a theoretical possibility of integrating not only architecture and urbanism but also architecture and countryside/rural planning. The first site explores the continuously articulated and connected spaces between building interior, urban interior, and territorial interior, in understanding Alberti's analogy, "A house is a little city." (1452) The second site illustrates architecture as an open boundary and a spatial medium which makes building, urban, and territorial interiors connect and makes them continuous. There is an opportunity of reading the continued relations and the continua of spaces. The third site deals with the form of building that architecture creates for building interior (society of rooms) and urban interior (society of urban rooms), and moderates the interiors. The last site clarifies the territorial interior (society of countryside/rural rooms) that constitutes homogeneous spatiality moderated by architecture between building interior and urban interior. The paper discusses the society of the continued interiors(building/urban/territorial interiors) that ought to be a fundamental truth in the field of every project which deals with a unit of space. It logically clarifies the society of the interiors, not isolated and blocked off but multilayered and continued. It comes to the conclusion that the territorial interior should be subsumed under the design field and the society of the continued rooms ought to be considered as a united object of space in the fields of interior architecture/design, architecture, landscape, urbanism and countryside/rural planning. Ultimately, it aims at offering a departing point of discourse and a theoretical foundation for the future studies on urban interior and territorial interior.

A Numerical Study on Safety According to the Excavation Step for Large Cross Section Tunnel (대단면 터널굴착에 있어서 굴착순서에 따른 수치해석적 안정성 검토)

  • Jung, Hee-sun;Yoon, Ji-sun
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.7 no.4
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    • pp.335-341
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    • 2005
  • In construction of a large cross section NATM tunnel, to keep the tunnel face stability by the ground itself bench cut method is commonly used. In order to necessity of partial face excavation method, we have to look for more enhanced method that can maintain better stress intensity. This paper presents a stress distribution of the Center Diaphragm Method from the partial face excavation methods, with the numerical analysis, and induced the optimal face distance, which is minimizing stress concentration and the optimal excavation step. Commerical 3 dimensional continuum analyzing FLAC-3D Ver. 2.1 program is used for the analysis. Analyses were performed to investigate ground behavior for tunnels with variable bench-length varying from 2m to 40m.

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Multiple Stakeholder Perspectives on Cancer Stigma in North India

  • Gupta, Adyya;Dhillon, Preet K;Govil, Jyotsna;Bumb, Dipika;Dey, Subhojit;Krishnan, Suneeta
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.14
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    • pp.6141-6147
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    • 2015
  • Background: Cancer is a leading cause of death worldwide. A large proportion of cancer deaths are preventable through early detection but there are a range of social, emotional, cultural and financial dimensions that hinder the effectiveness of cancer prevention and treatment efforts. Cancer stigma is one such barrier and is increasingly recognized as an important factor influencing health awareness and promotion, and hence, disease prevention and control. The impact and extent of stigma on the cancer early detection and care continuum is poorly understood in India. Objectives: To evaluate cancer awareness and stigma from multiple stakeholder perspectives in North India, including men and women from the general population, health care professionals and educators, and cancer survivors. Materials and Methods: A qualitative study was conducted with in-depth interviews (IDIs) and focus group discussions (FGDs) among 39 individuals over a period of 3 months in 2014. Three groups of participants were chosen purposively - 1) men and women who attended cancer screening camps held by the Indian Cancer Society, Delhi; 2) health care providers and 3) cancer survivors. Results: Most participants were unaware of what cancers are in general, their causes and ways of prevention. Attitudes of families towards cancer patients were observed to be positive and caring. Nevertheless, stigma and its impact emerged as a cross cutting theme across all groups. Cost of treatment, lack of awarenes and beliefs in alternate medicines were identified as some of the major barriers to seeking care. Conclusions: This study suggests a need for spreading awareness, knowledge about cancers and assessing associated impact among the people. Also Future research is recommended to help eradicate stigma from the society and reduce cancer-related stigma in the Indian context.

Development of Degenerated Beam Elements Using Higher-Order Displacement Profile (고차(高次) 변위(變位)를 고려(考慮)한 요소(要素)의 해석(解析))

  • Shin, Young Shik
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.2 no.3
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    • pp.75-86
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    • 1982
  • The degeneration of two classes of thick beam elements has been conducted, one (DB6) based on the conventional Timoshenko beam assumptions whereas the other (DB7) based on the assumed cubic axial displacement profile. While an adjustable shear correction factor is required for the DB 6 element to compensate for the unrealistic distribution of shear strain across the thickness, the DB 7 element assumes the more realistic quadratic profile of shear strain at the outset. With the plane-stress continuum solution as reference, solutions obtained by these two element models are compared with the analytical Timoshenko solution, the analytical thin beam solution and several available solutions of other existing beam elements. The result indicates that the performance of the higher order beam element DB 7 is consistently superior to any others. This is true for the whole range of aspect ratios of beam, in both static and free vibration analyses.

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Numerical estimation for safety factors of tunnels considering the failure of supports (지보재 파괴를 고려한 터널 안전율의 수치해석적 산정 연구)

  • You, Kwang-Ho;Park, Yeon-Jun;Hong, Keun-Young;Lee, Hyun-Koo;Kim, Jea-Kwon
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.7 no.1
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    • pp.37-49
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    • 2005
  • In a tunnel, failure of its supports can cause failure of the tunnel. Therefore it is important to estimate safety factor of the tunnel which the failure of its supports is taken into account. In previous studies, supports of tunnels were usually modelled as beam elements. The failure of the supports was decided by comparing the allowable stress and the calculated bending stresses inside the beam elements in estimating safety factor of the tunnel considering the failure of its supports. In this study, it is suggested how to model the supports properly. To this end, supports of a tunnel were modelled by both beam (elastic) elements and continuum (elasto-plastic) elements in two dimensional numerical analyses. Meanwhile, it was analyzed how rock mass class, coefficient of lateral pressure, shotcrete thickness, the existence of rock bolt, and excavation method had an effect on the safety factor of a tunnel.

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