• The Bulletin of The Korean Astronomical Society
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• v.35 no.2
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• pp.72.1-72.1
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• 2010

We present infrared and millimeter observations of the active star-forming complex W51. A $1.25\;deg\times1.00\;deg$ region that includes the W51 complex was covered in the J = 2 - 1 transition of the $^{12}CO$ and $^{13}CO$ molecules with the University of Arizona Heinrich Hertz Submillimeter Telescope. We use a statistical equilibrium code to estimate physical properties of the molecular gas. Using Spitzer data we identify young stellar objects (YSOs) and fit model spectral energy distributions to these sources and constrain their physical properties. We compare the molecular cloud morphology with the distribution of infrared and radio continuum sources and find associations between molecular clouds and YSOs. We estimate that about 1% of the cloud mass is currently in YSOs.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.1
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• pp.51.1-51.1
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• 2017

The galaxy cluster Abell 115 shows ongoing merger features, which suggest that it might be in an intermediate phase of dynamical evolution. As merging clusters often show, the characteristic hints of A115's merging activities include radio relics, double X-ray peaks, and large offsets between the cluster member galaxies and the X-ray distributions. To constrain the exact stage of the merger, it is necessary to obtain its dark matter distribution. In this study, we carry out a precision weak lensing study of this interesting system based on Subaru images. We present our mass reconstruction together with descriptions on our core procedure of the analysis: Subaru data reduction, galaxy shape measurement, and source selection. We find that Abell 115 consists of two massive dark matter clumps, which closely follow the cluster galaxies. Our weak lensing mass estimate is a few factors lower than the published dynamical mass obtained from velocity dispersion. This large mass discrepancy may be attributed to a significant departure from dynamical equilibrium.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.1
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• pp.49.3-50
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• 2017

Metallicity is one of the most important properties in understanding galaxy evolution. However, measuring metallicity is limited to low redshift (z<3.5) due to the faintness of the metallicity indicators in normal galaxies. For high redshift universe, active galactic nuclei (AGN) can be used to constrain the host galaxy metallicity. Previous studies investigated AGN metallicity using emission line flux ratios (i.e., NV/CIV and FeII/MgII), finding no evolution up to z~6. Those results might be due to selection effect since previous studies are based on very luminous AGNs. The observed luminosity-metallicity relation of AGNs (e.g., Nagao et al. 2006) suggests that luminous AGNs may be already matured at the observed epoch. Considering the luminosity-metallicty relation, we focused on low luminosity AGNs to find young AGNs (i.e., low metallicity). Through the Gemini/GNIRS observation in 2012A and 2015A (K-GMT GN-2015A-Q-203 PI: Shin, J.), we obtained the Gemini/GNIRS data for 7 high redshift AGNs (3.0

• The Bulletin of The Korean Astronomical Society
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• v.43 no.1
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• pp.61.2-61.2
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• 2018

ZwCL 1447.2+2619 is a merging galaxy cluster at z=0.37 with clear substructures in X-ray emission and galaxy distribution. In addition, the system possesses distinct radio relics. In order to constrain the merger scenario, it is necessary to measure both the distribution and mass of the cluster dark matter. We perform weak lensing analysis of ZwCL 1447.2+2619 using Subaru imaging data. We detect clear lensing signal from the cluster after carefully addressing instrumental systematics. In this poster, we present our preliminary results on our mass reconstruction and discuss the comparison with X-ray and radio results.

• Journal of applied mathematics & informatics
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• v.6 no.1
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• pp.203-216
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• 1999

In this paper a rational cubic interpolant spline with linear denominator has been constructed and it is used to constrain interpolation curves to be bounded in the given region. Necessary and sufficient conditions for the interpolant to satisfy the constraint have been developed. The existence conditions are computationally efficient and easy to apply. Finally the approximation properties have been studied.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.04a
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• pp.103-107
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• 2003

The objective of this thesis is to develop the optimal design of composite links containing complicated cross-section. To accomplish this objective, a composite links structural analysis program was developed. The method of calculating effective modulus of composite beam containing complicated cross-section is proposed. Genetic algorithm was implemented for the optimization method to manipulate the discrete ply angles as the design variables and to utilize its high reliability to find the global optimum. The design variables were the number of plies, the fiber orientations and the stacking sequence. The optimal design of composite links was performed by genetic algorithm to minimize the weight of the structure and to constrain ply failure

• Journal of Mechanical Science and Technology
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• v.18 no.1
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• pp.122-131
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• 2004

A constraint equation-based control law design for large angle attitude maneuvers of flexible spacecraft is addressed in this paper The tip displacement of the flexible spacecraft model is prescribed in the form of a constraint equation. The controller design is attempted in the way that the constraint equation is satisfied throughout the maneuver. The constraint equation leads to a two-point boundary value problem which needs backward and forward solution techniques to satisfy terminal constraints. An observer-based tracking control law takes the constraint equation as the input to the dynamic observer. The observer state is used in conjunction with the state feedback control law to have the actual system follow the observer dynamics. The observer-based tracking control law eventually turns into a stabilized system with inherent nature of robustness and disturbance rejection in LQR type control laws.

• Journal of Advanced Marine Engineering and Technology
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• v.30 no.8
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• pp.934-940
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• 2006

The aims of this study is to develop working robot for a installed trolley cable of an electric train and objective of this paper is to implement mobile control of working robot. In this paper an approach to method for scheme of a mobile control system is presented in a dynamic hybrid velocity/tension control of working robot. The working robot is composed the velocity and tension controllers using the concept of two-degrees-of-freedom servo-controller. This robot moved at same time a certain distance to constrain a constant tension and installed a trolley cable of an electric train. To move the robot the velocity control system have design and implemented. Simulation and experimental results are presented to illustrate the validity of designed mobil scheme.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.9C
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• pp.743-747
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• 2010

This paper presents an iterative adaptive hybrid image restoration algorithm for fast convergence. The local variance, mean, and maximum value are used to constrain the solution space. These parameters are computed at each iteration step using partially restored image at each iteration, and they are used to impose the degree of local smoothness on the solution. The resulting iterative algorithm exhibits increased convergence speed and better performance than typical regularized constrained least squares (RCLS) approach.

• Communications for Statistical Applications and Methods
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• v.23 no.2
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• pp.93-103
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• 2016

In the paper, we discuss dimension reduction of predictors ${\mathbf{X}}{\in}{{\mathbb{R}}^p}$ in a regression of $Y{\mid}{\mathbf{X}}$ with a notion of sufficiency that is called sufficient dimension reduction. In sufficient dimension reduction, the original predictors ${\mathbf{X}}$ are replaced by its lower-dimensional linear projection without loss of information on selected aspects of the conditional distribution. Depending on the aspects, the central subspace, the central mean subspace and the central $k^{th}$-moment subspace are defined and investigated as primary interests. Then the relationships among the three subspaces and the changes in the three subspaces for non-singular transformation of ${\mathbf{X}}$ are studied. We discuss the two conditions to guarantee the existence of the three subspaces that constrain the marginal distribution of ${\mathbf{X}}$ and the conditional distribution of $Y{\mid}{\mathbf{X}}$. A general approach to estimate them is also introduced along with an explanation for conditions commonly assumed in most sufficient dimension reduction methodologies.