• The KSFM Journal of Fluid Machinery
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• v.18 no.3
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• pp.46-52
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• 2015

Pump-turbine system is widely used by the hydropower industry for stabilizing the electrical grid in the vast growing economy of most developed countries. This study only investigates the Fluid-structure Interaction (FSI) analysis of the pump-turbine system at various operating conditions. The FSI analysis can show how reliable each component of the system is by providing the engineer with a better understanding of high stress and deformation points, which could reduce the lifespan of the pump-turbine. Pump-turbine components are categorized in two parts, pressurized static parts and movable stressed parts. The fixed parts include the spiral casing, top and bottom cover, stay vane and draft tube. The movable parts include guide vanes and impeller blades. Fine hexahedral numerical grids were used for CFD calculation and fine tetrahedral grids were used for structural analysis with imported load solution mapping greater than 90 %. The maximum equivalent stress are much smaller than the material yield stress, and the maximum equivalent stress showed an increasing tendency with the varying of operating conditions from partial to excessive at both modes. In addition, the total deformation of all the operating conditions showed a small magnitude, which have quite small influence on the structural stability. It can be conjectured that this system can be safely implemented.

• 한국지구물리탐사학회:학술대회논문집
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• 2008.10a
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• pp.79-84
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• 2008

Compared to conventional high resolution acoustic profiling, ultra high resolution shallow acoustic profiling is limited in penetration, yet it provides resolution suitable for detailed seabed investigation in the shallow waters. Possible applications include search of buried pipeline, ship wrecks, and other artificial objects through the detailed mapping of thickness and structure of the upper sedimentary layers. In this study, contaminated sediments were discriminated by the correlation of ultra high resolution profiles with geologic data. In addition, the burial depth of submarine cable was measured by the interpretation of acoustic anomalies in the profiles.

• Journal of the Korea Computer Graphics Society
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• v.26 no.3
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• pp.1-8
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• 2020

Ghosted illustration is an effective tool to simultaneously visualize interior and exterior structures while preserving clear shape cues. We propose a novel framework that combines 3D blending technique, which uses depth information of the target structure, with the conventional ghosted illustration framework. This combination facilitates natural blending effects tailored to the needs of ghosted illustration. Furthermore, we present how common manipulation techniques (e.g., masking) and illustrative rendering effects (e.g., silhouette mapping) can be integrated into the proposed framework to preserve both clear shape cues and depth cues. For the compositing techniques, we show and discuss the visual results obtained from various combinations of them. This demonstrates that the proposed framework can be an effective tool for ghost illustration.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.7
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• pp.1480-1487
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• 2004

This study is proposed the novel gesture recognition method for the remote camera robot control. To recognize the dynamics gesture, the preprocessing step is the image segmentation. The conventional methods for the effectively object segmentation has need a lot of the cole. information about the object(hand) image. And these methods in the recognition step have need a lot of the features with the each object. To improve the problems of the conventional methods, this study proposed the novel method to recognize the dynamic hand gesture such as the MMS(Max-Min Search) method to segment the object image, MSM(Mean Space Mapping) method and COG(Conte. Of Gravity) method to extract the features of image, and the structure of recognition MLPNN(Multi Layer Perceptron Neural Network) to recognize the dynamic gestures. In the results of experiment, the recognition rate of the proposed method appeared more than 90[%], and this result is shown that is available by HCI(Human Computer Interface) device for .emote robot control.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.93-96
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• 2017

DDS (Data Distribution Serivce) communication middleware is spreading to various private sector as well as the defense sector because it can obtain a very high application effect in a complex system environment in which a plurality of data producers and data consumers are connected by a network. However, application development using DDS middleware is an inefficient structure with a lot of repetitive codes because most users perform 1: 1 mapping with the message they want to exchange. Accordingly, the user has to perform unnecessary repetitive tasks as the topic increases. Therefore, a development support tool that identifies a series of processes required for using DDS middleware and automatically generates the classes that are repeated by Topic is required. In this paper, we propose a method for DDS communication by automatically generating a common class for efficient use of DDS middleware.

• Publications of The Korean Astronomical Society
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• v.30 no.2
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• pp.133-137
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• 2015

The Galactic center uniquely provides opportunities to resolve how star clusters form in neutral gas overdensities engulfed in a large-scale accretion flow. We have performed sensitive Green Bank 100m Telescope (GBT), Karl G. Jansky Very Large Array (JVLA), and Submillimeter Array (SMA) mapping observations of molecular gas and thermal dust emission surrounding the Galaxy's supermassive black hole (SMBH) Sgr $A^{\ast}$. We resolved several molecular gas streams orbiting the center on ${\gtrsim}10$ pc scales. Some of these gas streams appear connected to the well-known 2-4 pc scale molecular circumnuclear disk (CND). The CND may be the tidally trapped inner part of the large-scale accretion flow, which incorporates inflow via exterior gas filaments/arms, and ultimately feeds gas toward Sgr $A^{\ast}$. Our high resolution GBT+JVLA $NH_3$ images and SMA+JCMT 0.86 mm dust continuum image consistently reveal abundant dense molecular clumps in this region. These gas clumps are characterized by ${\gtrsim}100$ times higher virial masses than the derived molecular gas masses based on 0.86 mm dust continuum emission. In addition, Class I $CH_3OH$ masers and some $H_2O$ masers are observed to be well associated with the dense clumps. We propose that the resolved gas clumps may be pressurized gas reservoirs for feeding the formation of 1-10 solar-mass stars. These sources may be the most promising candidates for ALMA to probe the process of high-mass star-formation in the Galactic center.

• Journal of Ginseng Research
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• v.19 no.1
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• pp.56-61
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• 1995

Molecular cloning and restriction mapping on ATPase $\alpha$-subunit gene (atpA) were carried out to obtain genomic information concerned with the gene structure and organization in Korean ginseng mitochondria. Two different clones containing the homologous sequence of atpA gene were selected from SalI and PstI libraries of mitochondrial DNA (mtDNA) of Korean ginseng. The sizes of mtDNA fragments inserted in SalI and PstI clones were 3.4 kb and 13 kb, respectively. Southern blot analysis with [$^{32}P$] labelled Oenothera atPA gene probe showed that atpA gene sequence was located in 2.0 kb XkaI fragment in PstI clone and in 1.7 kb XbaI fragment in SalI clone. A partial sequening ascertained that the SalI clone included about 1.2 kb fragment from SalI restriction site to C-terminal sequence of this gene but about 0.3 kb N-terminal sequence of open reading frame was abscent. The PstI fragment was enough large to cover the full sequence of atpA gene. The same restriction pattern of the overlapped region suggests that both clones include the same fragment of atiA locus. Data of Southern blot analysis and partial nucleotide sequencing suggested that mtDNA of Korean ginseng has a single copy of atpA gene. Key words ATPase a-subunit, mitochondrial DNA, Panax ginseng.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.12
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• pp.2834-2851
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• 1997

In this paper, a design and implementation of VHDL compiler front-end, aims at supporting the full-set of VHDL '87 & '93 LRM and carring out the preprocessing of VHDL-to-C, is described. The VHDL compiler front-end includes 1)the symbol tree of analyzed data to represent the hierarchy, the scope and visibility, the overloading and homograph, the concurrent multiple stacks in VHDL, 2)the data structure and supportig routies to deal with the objects, the type and subtype, the attribute and operation in VHDL, 3)the analysis of the concurrent/sequential statements, the behavior/structural descriptions, of semantic token and the propagation of symbol & type to improve the registration and retrieval procedure of analyzed data. In the experiments with Validation Suite, the VHDL compiler front-end could support the full-set specification of VHDL LRM '87 & '93; and in the experiments to asses the performance of symantic token for the VHDL hierachy/visibility/concurrency/semantic checking, the improvement of about 20-30% could be achieved.

• Economic and Environmental Geology
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• v.34 no.2
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• pp.193-204
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• 2001

A geophysical survey was undertaken at Wiri area, Andong, to delineate subsurface structure and reveal the fault zone nearby which heaving of road and subsidence of slope occurred in 1997, especially in the heavy rainy season. Electrical resistivity methods of dipole-dipole array profiling and Schlumberger array sounding and seismic methods of refraction and reflection were performed for the mapping of clay layer, which was interpreted to be the major factor among the reasons of slope deformation. The clay layer was characterized by lower electrical resistivities (< $100{\Omega}{\cdot}m$) and lower seismic velocities (<400 m/s), respectively. The results of electrical and seismic surveys showed that subsidence of slope was probably associated with sliding of wet clay on 18SW/NNW trending fault plane, while heaving of road was probably caused by upward movement of the wet clay through subvertical NNE trending fault.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.397-397
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• 2010

Bone is considered as hierarchically organized biocomposites of organic (collagen) and inorganic (hydroxyapatite) materials. The precise structural dependence between hydroxyapatite (HAp, $Ca_{10}(PO_4)_6(OH)_2)$ crystals and collagen fibril is critical to unique characteristics of bone. To meet those conditions and obtain optimal properties, it is essential to understand and control the initial growth mechanisms of hydroxyapatite at the molecular level, such as other nano-structured materials. In this study, collagen fibrils were prepared by adsorbing native type I collagen molecules onto hydrophobic surface. Hydrophobicity was introduced on the Si wafer surface by using PECVD (plasma enhanced chemical vapor deposition) method and cyclohexane as a precursor. Biomimetic nucleation and growth of HAp on the self-assembled collagen nanofibrils were occurred through incubation of the sample in SBF (simulated body fluid). Chemical and morphological evolution of HAp nanocrystals was investigated by surface-sensitive analytical techniques such as ToF-SIMS (Time-of-Flight Secondary Ion Mass Spectrometry) and AFM (Atomic Force Microscopy) in the early growth stages (< 24 hrs). The very initial stages (< 12 hrs) of mineralization could be clearly demonstrated by ToF-SIMS chemical mapping of surface. In addition to ToF-SIMS and AFM measurement, scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction analysis were conducted to characterize the HAp layer in the late stages. This study is of great importance in the growth of real bone-like materials with a structure analogous to that of natural bones and the development of biomimetic nanomaterials.