• Journal of The Korean Astronomical Society
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• v.40 no.1
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• pp.1-7
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• 2007

About 10 percent of quasars are known to exhibit deep broad absorption troughs blueward of prominent permitted emission lines, which are usually attributed to the existence of outflows slightly above he accretion disk around the supermassive black hole. Typical widths up to 0.2c of these absorption roughs indicate the velocity scales in which special relativistic effects may not be negligible. Under he assumption of the ubiquity of the broad absorption line region in quasars, the broad emission line flux will exhibit Thomson scattered components from these fast outflows. In this paper, we provide our Monte Carlo calculation of linear polarization of singly Thomson scattered line radiation with the careful considerations of special relativistic effects. The scattering region is approximated by a collection of rings that are moving outward with speeds ${\upsilon}=c{\beta}<0.2c$ near the equatorial plane, and the scattered line photons are collected according to its direction and wavelength in the observer's rest frame. We find that the significantly extended red tail appears in the scattered radiation. We also find that the linear degree of polarization of singly Thomson scattered line radiation is wavelength-dependent and hat there are significant differences in the linear degree of polarization from that computed from classical physics in the far red tail. We propose that the semi-forbidden broad emission line C III]1909 may be significantly contributed from Thomson scattering because this line has small resonance scattering optical depth in the broad absorption line region, which leads to distinct and significant polarized flux in this broad emission line.

• Journal of Astronomy and Space Sciences
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• v.5 no.2
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• pp.129-141
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• 1988

Using the numerical solution in the plane restricted problem of three bodies, abut 490 periodic orbits are computed numerically around the $L_5$ of Sun-Jupiter and about 1600 periodic orbits also be done around the $L_5$ of Sun-Jupiter system. But, in Earth-Moon system, the complex shapes and dents appear around the $L_5$ and periodic orbits intersect one another in the place where dents are shown. And there is a region that three different periodic orbits exist with the same period in this system. The increase of energy is in inverse proportion to that of period in the part of this region. The regions can exist around the $L_5$ of Sun-Jupiter system where periodic orbit can be unstable by perturbation of other force besides the gravitational force of Jupiter. These regions which is close to $L_5$ are a~5.12 AU. The Trojan asteroids that have a small eccentricity and inclination can not exist in this region.

• Bulletin of the Korean Space Science Society
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• 2009.10a
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• pp.36.2-36.2
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• 2009

We present GALEX (Galaxy Evolution Explorer) far (FUV) and near (NUV) ultraviolet imaging of 34 nearby early-type galaxies from the SAURON representative sample of 48 E/S0 galaxies, all of which have ground-based optical imaging from the MDM Observatory. The surface brightness profiles of nine galaxies (~26 per cent) show regions with blue UV-optical colours suggesting recent star formation. Five of these (~15 per cent) show blue integrated UV-optical colours that set them aside in the NUV integrated colour-magnitude relation. These are objects with either exceptionally intense and localised NUV fluxes or blue UV-optical colours throughout. They also have other properties confirming they have had recent star formation, in particular Hbeta absorption higher than expected for a quiescent population and a higher CO detection rate. This suggests that residual star formation is more common in early-type galaxies than we are used to believe. NUV-blue galaxies are generally drawn from the lower stellar velocity dispersion (sigma_e <200 km/s) and thus lower dynamical mass part of the sample. We have also constructed the first UV Fundamental Planes and show that NUV blue galaxies bias the slopes and increase the scatters. If they are eliminated the fits get closer to expectations from the virial theorem. Although our analysis is based on a limited sample, it seems that a dominant fraction of the tilt and scatter of the UV Fundamental Planes is due to the presence of young stars in preferentially low-mass early-type galaxies.

• The Journal of Fisheries Business Administration
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• v.25 no.2
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• pp.115-145
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• 1994

The objetives of this study are to find the economic feasibility of the polyculture and to give the economic information of the polyculture for aquaculture fishermen. The polyculture is defined as the rearing of several species together to make more efficient use of the growing space and the total ground environment. The economic feasibility analysis in the polyculture involves the profitability, the productivity, and the risk reduction effect. The results of the economic feasibility analysis in the polyculture are as follows; First, in the profitability analysis, the solid utilization of ground in the polyculture is more profitable than the monoculture. The profitability owing to the plane utilization of the ground in the polyculture is positioned between those of the monoculture of each speices. Second, in the productivity analysis, oyster and sea squirt are diminishing returns to scale. Third, the variation on the average rate of return in the polyculture products is smaller than that of the monoculture. Finally, the result of comparison between the polyculture and the monoculture shows that the polyculture in coastal area is more profitable and more efficient than the monoculture. Most of cultivating species are selective in their diet Thus, stocking different kinds of cultivating species will efficiently utilize space and food It seems that polyculture is more appropriate for those species that live in different ecological niches. We think that the production per unit of ground can be increased, and the fixed cost per unit of output be reduced, so the polyculture is more profitable than the monoculture. Based on the above results, we concludes that the polyculture is economically feasible when profitability and productivity are increased and simultaneously the variation of average rate of return in the polyculture is smaller than that of the monoculture.

• Journal of the Earthquake Engineering Society of Korea
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• v.1 no.4
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• pp.59-68
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• 1997

In analysis of underground structures, the effects of artificial boundary conditions are considered as one of the major reasons for differences from experimental results. These phenomena can be overcome by using the boundary elements which satisfy the multi-layered half space conditions. The fundamental solutions of multi-layered half-space for boundary element method is formulated satisfying the transmission and reflection of waves at each layer interface and radiation conditions at bottom layer. The governing equations can be obtained from the displacements at each layer which are expressed in terms of harmonic functions. All types of waves can be included using the complete response from semi-infinite integrals with respect to horizontal wavenumbers using expansion of Fourier series and Hankel transformation. Two dimensional Green's functions are derived from cylindrical Navier equations and potentials performing infinite integration in y-direction. In this case, it is effective to transform into two dimensional problem using semi-analytical integration and sinusoidal Bessel function. Some verifications are given to show the accuracy and efficiency of the developed method, and numerical examples to demonstrate the dynamic behavior of underground with various properties.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.1
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• pp.49.2-49.2
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• 2014

The MIRIS (Multi-purpose InfraRed Imaging System) is a compact IR space Telescope, which has been developed by KASI since 2008 as the main payload of Korean STSAT-3. It was launched successfully by a Dnepr Rocket at Yasny Launch site, Russia in November 2013. After the launch, the STSAT-3 successfully settled down at Sun synchronous orbit with altitude of ~ 600km. Communications were regularly made between the ground station and the MIRIS with other secondary payload. We made a series of tests of the MIRIS during the verification period and found that all functions including the passive cooling are working as expected. The MIRIS has a wide-field of view $3.67{\times}3.67$ degrees and wavelength coverage from 0.9 to 2.0 micro-meter with the angular resolution of 51.6 arcsec. The main science missions of the MIRIS are (1) mapping of the Galactic plane with Paschen-alpha line (1.88 micro-meter) for the study of warm interstellar medium and (2) the measurement of large angular fluctuations of cosmic near infrared background radiation with I (1.05 micro meter) and H (1.6 micro meter) bands to identify their origin. We present the results of MIRIS initial operation in this paper.

• Korean Institute of Interior Design Journal
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• v.26 no.6
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• pp.53-61
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• 2017

Cityschumers experience the urban with the visual perception while walking an average speed of 4km per hour. At this time, recognition of the color field accounts for more than 70%. Therefore, in this paper the environmental color of urban street is examined by dividing the pedestrian visual field area. In the urban street, the area of the visual field area of the pedestrian is divided into Ground Plane, Roadside, Canopy and Building Wall. In addition, we observe and color survey the environmental color of Exhibition Road, which is the northern side space of South Kensington in London, which adopted the world's first shared space. The color of the visual filed area was dominated as YR, GY, Y, PB. The Ground Pland was dominated by the YR. The reason for this is that the color of the floor has changed due to the shadows of surrounding architecture and facilities. Roadside was dominated in various ways such as GY, BG, PB, B and P. Canopy was mainly composed of PB, GY, etc. It was found that the material color of the lower part of the architecture was reflected. The architecture wall was affected by the reflectance and absorption rate of the transparent material. The first image that comes to mind when thinking about the urban is the street where pedestrians walk, feel and enjoy themselves. Therefore, it is suggested that various policy frameworks for managing and managing urban planning professionals may be different from the perceptions of pedestrians active in mega cities.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.122-122
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• 2012

Geosynchronous electron flux dropouts are most likely due to fast drift loss of the particles to the magnetopause (or equivalently, the "magnetopause shadowing effect"). A possible effect related to the drift loss is the radial diffusion of PSD due to gradient of PSD set by the drift loss effect at an outer L region. This possibly implies that the drift loss can affect the flux levels even inside the trapping boundary. We recently investigated the details of such diffusion process by solving the diffusion equation with a set of initial and boundary conditions set by the drift loss. Motivated by the simulation work, we have examined observationally the energy spectrum and pitch angle distribution near trapping boundary during the geosynchronous flux dropouts. For this work, we have first identified a list of geosynchronous flux dropout events for 2007-2010 from GOES satellite electron measurements and solar wind pressures observed by ACE satellite. We have then used the electron data from the Time History of Events and Macroscale Interactions during Substorms (THEMIS) spacecraft measurements to investigate the particle fluxes. The five THEMIS spacecraft sufficiently cover the inner magnetospheric regions near the equatorial plane and thus provide us with data of much higher spatial resolution. In this paper, we report some case studies showing energy dependence during magnetopause shadowing effect.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.816-819
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• 2005

This paper proposes a coordinate correction technique using the transformation of 3D parabolic coordinate function and BP(Back Propagation) neural network in order to solve space distortion problem caused by using catadioptric camera. Although Catadioptric camera can obtain omni-directional image at all directions of 360 degrees, it makes an image distorted because of an external form of lens itself. Accordingly, To obtain transformed ideal distance coordinate information from distorted image on 3 dimensional space, we use coordinate transformation function that uses coordinates of a focus at mirror in the shape of parabolic plane and another one which projected into the shape of parabolic from input image. An error of this course is modified by BP neural network algorithm.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.2
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• pp.17-25
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• 2006

In the present study, a 2-D chimera technique for overlapped bodies in relative motion is developed using unstructured triangular meshes. The solid boundary nodes located next to the intersecting point between bodies are merged to the intersecting point to assure accurate representation of the intersecting region. In order to assign proper value of flow variables at the nodes located out of the computational field, interpolation is conducted for non-active nodes. For validation, the motions of a NACA64A006 airfoil and a NACA0012 airfoil with a plane flap are computed and the results are compared with other simulations. The motion of a launching missile ejected from a NACA0012 airfoil is also simulated.