• 한국전산유체공학회:학술대회논문집
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• 2008.03a
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• pp.221-226
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• 2008

Numerical simulation is performed for microdroplet deposition on a pre-patterned micro-structure. The level-set method for tracking the liquid-gas interface is extended to treat the immersed (or irregular-shaped) solid surface. The no-slip condition at the fluid-solid interface as well as the matching conditions at the liquid-gas interface is accurately imposed by incorporating the ghost fluid approach based on a sharp-interface representation. The method is further extended to treat the contact angle condition at an immersed solid surface. The present computation of a patterning process using microdroplet ejection demonstrates that the multiphase characteristics between the liquid-gas-solid phases can be used to improve the patterning accuracy.

• 한국전산유체공학회:학술대회논문집
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• 2008.10a
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• pp.221-226
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• 2008

Numerical simulation is performed for microdroplet deposition on a pre-patterned micro-structure. The level-set method for tracking the liquid-gas interface is extended to treat the immersed (or irregular-shaped) solid surface. The no-slip condition at the fluid-solid interface as well as the matching conditions at the liquid-gas interface is accurately imposed by incorporating the ghost fluid approach based on a sharp-interface representation. The method is further extended to treat the contact angle condition at an immersed solid surface. The present computation of a patterning process using microdroplet ejection demonstrates that the multiphase characteristics between the liquid-gas-solid phases can be used to improve the patterning accuracy.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.1
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• pp.63-70
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• 2009

Proposed in the paper is an algorithm to generate tool-path for sculptured surface machining. The proposed algorithm computes tool path by slicing offset triangular mesh, which is the CL-surface (Cutter Location surface). Since the offset triangular mesh includes invalid triangles and self-intersections, it is necessary to remove invalid portions. For the efficient removal of the invalid portions, we extended the sweep line algorithm. The extended sweep line algorithm removes invalid portions very efficiently, and it also considers various degeneracy cases including multiple intersections and overlaps. The proposed algorithm has been implemented and tested with various examples.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.1
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• pp.30.2-30.2
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• 2021

The extended Lyα nebulae (also known as Lyα blobs or LABs) observed at z=2-6 can provide clues to galaxy formation in the early universe. The connection of LABs with the overdensities of compact Lyα emitters suggests that they are associated with matter density peaks in the universe and thus likely to evolve into the present-day groups and clusters of galaxies. However, the mechanism powering the extended Lyα emission in LABs is remained controversial. The detection of polarization signals that follow the theoretically predicted trend is interpreted as strong evidence supporting that the LABs are caused primarily by the resonance scattering of Lyα originating from star-forming galaxies and AGNs. However, Trebitsch et al. (2016) claimed that the radial profile of polarization could be better explained by the scenario in which Lyα photons are produced in the cooling gas surrounding galaxies and then self-scattered by the gas, rather than by the scattering scenario of photons originating from the central galaxies. In this presentation, using LaRT, a state-of-art Lyα radiative transfer code, it is demonstrated that the observed polarization pattern can be reproduced even with the scattering scenario.

• Journal of Digital Convergence
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• v.14 no.4
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• pp.407-418
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• 2016

The purpose of this study was to investigate the effect of career preparation program on self-esteem, self-efficacy related career decision-making and career development readiness in university students. The structured career development program was given in 124 participants, Sep.~Dec, 2014 in D city. SPSS/Win 18.0. was used. The 1.06 points were decreased in self-esteem(t=3.39, p=.00) than before. The 14.22 points, 17.36 points were increased in self-efficacy(t=-12.41, p=.00), and career development readiness(t=-13.85, p=.00) than before. It showed the program was effective. Three variables showed correlation with one another. We suggested this structured career preparation program would be applied and extended more in career development for the college students. And the follow-up studies about self esteem and relating factors will be needed.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.7
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• pp.140-145
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• 1989

In this paper, we present an effective circuit placement method called SOAP (self-organization assisted placement) for rectilinear or arbitrarily-shaped region arised form the layout of ASIC (application specific integrated circuit). Self-organization is a learning algorithm for neural networks proposed by [1] which adjusts weights of synapses connected to neurons such that topologically close neurons are sensitive to inputs that are physically similar. In SOAP, we obtain a good circuit placement result in arbitrarily-shaped region by replacing the block of circuit and the position (x, y coordinates) of the block with the neuron and the weight pair of synapses connected to the neuron, respectively. This method can also be extended to the circuit placement over the nonplanar surface.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.10
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• pp.955-961
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• 2006

The global ultrasonic system for the self-localization of a mobile robot consists of several ultrasonic transmitters fixed at some reference positions in the global coordinates of robot environment. By activating the ultrasonic transmitters, the mobile robot is able to get the distance to the ultrasonic transmitters and compute its own position in the global coordinate. Due to the limitation on the ultrasonic signal strength and beam width as well as the environmental obstacles however, the ultrasonic signals from some generator may not be transmitted to the robot. Thus, instead of activating the all ultrasonic transmitters, it is necessary to select some ultrasonic generators to activate based on the current robot position. In this paper, we propose a selective activation algorithm for self-localization with the global ultrasonic system. The selective activation algorithm gets the meaningful ultrasonic data at every sampling instants, which results in the faster and more accurate response of the self-localization than the conventional sequential activation. Through the self-localization and path following control, we verify the effectiveness of the proposed selective activation algorithm.

• The Korean Journal of Applied Statistics
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• v.18 no.1
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• pp.129-135
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• 2005

Representative observations are useful to express explicitly the distributional variation of the data by a few selected observations corresponding to the quantiles in the univariate situation. Jones and Rice(1992) extended it to the multidimensional case by the principal component based method. This study introduces a modified version of Jones and Rice exploiting the self-consistency of principal components in expressing the chosen observation vectors. Compared to that of Jones and Rice, the suggested method tends to provide with less susceptible representative observations to the sampling variation of the data and the resulted vectors benefits from the self-consistency.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.8
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• pp.1893-1898
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• 1998

We have redefined the $\alpha$ -parameter of the extended transmitters in the presence of self-phase modulation (SPM) induced chirp. The $\alpha$ -parameter is effectively lowered to about 1, when the SPM effect with the launching power of 12.5dBm (maximum launching power to avoid stimulated Brillouin scattering(SBS)) is included, compared to the $\alpha$ -parameter of the transmitter algone. The lowered $\alpha$ -parameter has improved the transmission performance significantly regardless the transmitter is operated with positive or negative chirp. The SPM-induced effective $\alpha$ -parameter can be used as a design parameter for the high speed (10 Gbps) transmission systems.

• Journal of Information Technology Services
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• v.14 no.3
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• pp.163-182
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• 2015

The spread of mobile commerce due to popularization of smartphones not only broke down the boundary between online and offline, but also changed the consumer life, and hence brought change of commerce paradigm that creates new demand. The success of innovative information technology such as mobile shopping can be defined as an individual accepting the technology and continuously using it, but the studies on the usage behavior after the acceptance have been done in very restrictively, despite its importance. In this study, in order to empirically investigate the factors that influence the continuance in mobile shopping usage experience and its causal relationship, Social Cognitive Theory and Habit Theory were applied to IS Continuance Model, and the extended IS Continuance Model was suggested and proved. As a result, the usefulness, enjoyment, and self-efficacy perceived in usage experience significantly influence satisfaction, and usefulness, self-efficacy, and satisfaction influence habit. Also, usefulness, self-efficacy, satisfaction, and habit significantly influence continuance intention. This study provides a valuable asset in providing an opportunity to understand the usage behavior of mobile shopping service users after the acceptance, and furthermore proving directionality in improving customer loyalty.