• The Bulletin of The Korean Astronomical Society
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• v.41 no.1
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• pp.72.2-72.2
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• 2016

The SDSS-IV extended Baryon Oscillation Spectroscopic (eBOSS) will provide new photometry and spectroscopy of an unprecedented number of quasars in a novel redshift range, along with some re-observations of SDSS DR12 objects. We present here an observational study of the geometry, spatial distribution, luminosity function, and clustering of a sample of low- and high-z quasars obtained from the first SDSS-IV data release (DR13). In particular, we characterize the amount of overlapping between different data releases, and then focus on the synergy among high- and low-z quasars as tracers of the cosmic web, particularly considering their cross-correlations and cosmological implications.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.1
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• pp.77.3-77.3
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• 2016

In our previous study, we showed that the peculiar globular cluster M22 contains two distinct stellar populations with different physical properties, having different chemical compositions, spatial distributions and kinematics. We proposed that M22 is most likely formed via a merger of two GCs with heterogeneous metallicities in a dwarf galaxy environment and accreted later to our Galaxy. In their recent study, Mucciarelli et al. claimed that M22 is a normal mono-metallic globular cluster without any perceptible metallicity spread among the two groups of stars, which challenges our results and those of others. We devise new strategies for the local thermodynamic equilibrium abundance analysis of red giant branch stars in globuar clusters and show there exists a spread in the iron abundance distribution in M22.

• Korean Institute of Interior Design Journal
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• v.15 no.2 s.55
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• pp.118-126
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• 2006

This study aims at analyzing the characteristics and trends of future workplace in reference to the case for Digital Nomad Space (DNS). For this study, it has been investigated how to converge meanings of the digital environment and physical office space by which surveys to potential digital nomads were fulfilled. As a result, the types and the properties of future workplace in digital environment have been obtained. This study also includes general characteristics and design aspects of the time-based ubiquitous rental workplace followed by investigating future trends of the digital era. Thus, suggestions of spatial requirements of the digitalized office towards the practical level in the architectural interior design is proposed, and DNS has special features such as the cultural complex and ICT-based facilities with free accessibility to existing information and data over the air.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.755-757
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• 2009

We developed a novel patterning method of organic light emitting materials using a laser-inscribed sacrificial layer for fabricating high-resolution pixels in organic light emitting displays (OLEDs). Our patterning process is capable of achieving high spatial resolution of about 10 ${\mu}m$. Moreover, it has no detrimental effect on the electrical properties of organic materials. This patterning approach is expected to be applicable for patterning and integrating a wide range of organic materials for organic electronic and optoelectronic devices.

• ETRI Journal
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• v.26 no.5
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• pp.467-474
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• 2004

In a High Altitude Platform (HAP) cellular communications network, each cell may be served by a dedicated spot-beam antenna. The antennas' beam properties and their spatial overlap control the co-channel interference. In prior literature, radiation patterns have been approximated by a main lobe followed by a constant sidelobe floor. A network of 121 cells has been studied and the method is here extended to the use of more realistic radiation patterns based on the theoretical aperture antenna patterns. This allows for the comparison of the effect of different aperture field tapers, which lead to reduced sidelobe levels and hence higher system capacity but also a more massive antenna payload.

• Steel and Composite Structures
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• v.11 no.6
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• pp.489-504
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• 2011

This paper presents a theoretical investigation in free vibration of sigmoid functionally graded beams with variable cross-section by using Bernoulli-Euler beam theory. The mechanical properties are assumed to vary continuously through the thickness of the beam, and obey a two power law of the volume fraction of the constituents. Governing equation is reduced to an ordinary differential equation in spatial coordinate for a family of cross-section geometries with exponentially varying width. Analytical solutions of the vibration of the S-FGM beam are obtained for three different types of boundary conditions associated with simply supported, clamped and free ends. Results show that, all other parameters remaining the same, the natural frequencies of S-FGM beams are always proportional to those of homogeneous isotropic beams. Therefore, one can predict the behaviour of S-FGM beams knowing that of similar homogeneous beams.

• Computers and Concrete
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• v.7 no.1
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• pp.39-51
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• 2010

The system of pores of autoclaved aerated concrete (AAC) is described by the so-called cherry-pit model, a random system of partially interpenetrating spheres. For the simulation of fracture processes, the solid phase is approximated by an irregular spatial network of beams obtained by means of the so-called radical tessellation with respect to the pore spheres. FE calculations using standard software (ANSYS) yield the strain energies of the beams. These energies are used as fracture criterion according to which highly loaded beams are considered as broken and are removed from the network. The paper investigates the relationship between mean fracture strength and microstructure for structures close to real AAC samples and virtual structures with particular geometrical properties.

• Journal of the Korea Society of Computer and Information
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• v.21 no.9
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• pp.37-43
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• 2016

This paper introduces a method for video shot group detection needed for efficient management and summary of video. The proposed method detects shots based on low-level visual properties and performs temporal and spatial clustering based on visual similarity of neighboring shots. Shot groups created from temporal clustering are further clustered into small groups with respect to visual similarity. A set of representative shot frames are selected from each cluster of the smaller groups representing a scene. Shots excluded from temporal clustering are also clustered into groups from which representative shot frames are selected. A number of video clips are collected and applied to the method for accuracy of shot group detection. We achieved 91% of accuracy of the method for shot group detection. The number of representative shot frames is reduced to 1/3 of the total shot frames. The experiment also shows the inverse relationship between accuracy and compression rate.

• Bulletin of the Korean Chemical Society
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• v.28 no.6
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• pp.995-998
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• 2007

Pentacene moiety has been widely studied in Organic Thin-Film Transistor (OTFT) device as a channel layer because of high carrier mobility. In this study, we have fabricated vertical type Organic Static Induction Transistors (SITs) using pentacene, 6,13-Dinaphthalen-1-ly-Pentacene (1-DNP, 3), and 6,13-Dinaphthalen-2- ly-Pentacene (2-DNP, 4). 1-DNP and 2-DNP have same naphtyl group with pentacene, but different linked position and spatial arrangement. We have checked the static characteristics of materials in vertical type SITs device. We found that pentacene has as on/off ratio of 14.56, 1-DNP and 2-DNP shows as on/off ratio of 36.58 and 6.61 at VDS = 2V in SIT, respectively.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.72.2-72.2
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• 2012

We analyzed the properties of shock waves in galaxy clusters, by using the data of simulations for the large-scale structure of the universe with the spatial resolution of up to 25 kpc/h. In a substantial fraction of clusters, we found that strong shocks with Mach number of several or larger exist in outskirts within the virial radius. They are produced by the accretion of warm gas flowing from filaments to clusters, and generate large cosmic-ray fluxes. The cosmic rays advect into cluster cores, but may temporally induce the population inversion, that is, larger population at larger radius, suggested by recent radio and ${\gamma}$-ray observations.