• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.9
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• pp.782-787
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• 2008

First, the effect of the geometry such as the curved shape of the struts composing the truss structure of WBK is elaborated. Then, analytic solutions for the material properties of WBK and the maximum loads of a WBK-cored sandwich panel under bending are derived. A design optimization with the face sheet thickness and the core height selected as the design variables is presented for given slenderness ratios of the WBK core. Unless the face sheet thickness is limited, the optimal design to give the maximum load per weight is always found at a confluence of three failure modes, namely, face sheet yielding, indentation plastic, and core shear modeB plastic.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1998.06b
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• pp.122-127
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• 1998

In this paper, we focus on the information retrieval of human individuals who are recorded on the video database. Our purpose is to index persons by their faces or voice and to retrieve their existing time sections on the video data. The database system can track as well as extract a face or voice of a certain person and construct a model of the individual person in self-organization mode. If he appears again at different time, the system can put the mark of the same person to the associated frames. In this way, the same person can be retrieved even if the system does not know his exact name. As the face and speaker modeling, a subspace method is employed to improve the indexing accuracy.

• Composites Research
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• v.16 no.3
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• pp.18-24
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• 2003

Sandwich structures have been widely used in the applications of vessel industry, where high structural stiffness is required with small addition of weight. It is so significant to think of the effect of the variables in the design process of the sandwich structure for the concentrated loads. This paper describes the influence of design variables, such as core density, core thickness and face thickness ratio, on the strength of sandwich beam. The theoretical failure loads based on the 2-D elasticity theory agree well with the experimental yield or failure loads, which are measured at the three point bending laboratory test using AS4/3501-6 facing and polyurethane foam core sandwich beam. The comparison of those yield or failure loads was also done with the ratio of the top to bottom face thickness. The theoretical optimum condition is obtained by finding the intersection point of failure modes involved, which gives optimum core density of the sandwich beam for strength and stiffness. In the addition, the effect of unequal face thickness for the optimized and off-optimized sandwich beams for the strength was compared with the ratio of loading length to beam length, and the variations of strength and stiffness were discussed with the relative ratio of core to face mass.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.156.2-156.2
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• 2016

The variation of the surface structure of the Al adsorbed W(110) planes according to the coverage and the substrate temperature has been investigated using LEED and ISS When the Al atoms were adsorbed on the W(110) surface at room temperature, a p($1{\times}1$) of the fcc (111) face were found at the coverage higher than 4 ML. When the substrate temperature was kept at 900 K during Al adsorption and the coverage was 1.0 ML, the surface revealed a p($1{\times}1$) of the bcc(110) face and when the coverage is 1.5 ML, the surface showed a p($1{\times}1$) of the bcc (110) face together with a p($1{\times}1$) double domain structure (fcc (111) face) rotated ${\pm}3^{\circ}$ from the [100] direction of the W(110) surface. When Al atoms were adsorbed on the W(110) surface at the substrate temperature of 1000 K and the coverage was higher than 1.0 ML, the surface revealed a p($1{\times}1$) of the bcc(110) face together with p($1{\times}1$) double domain structure(fcc(111) face) rotated ${\pm}3^{\circ}{\sim}5^{\circ}$ from the [100] direction of the W(110) surface. When Al atoms were adsorbed on the W(110) surface at the substrate temperature of 1100 K and the coverage was 0.5 ML, Al atoms formed a p($2{\times}1$) double domain structure When the coverage was 1.0 ML, the double domain hexagonal structure (fcc(111) face) rotated ${\pm}5^{\circ}$ from the [100] direction of the W(110) surface and another distorted hexagonal structure was found. Low-energy electron diffraction results along with ion scattering spectroscopy results showed that the Al atoms followed the Volmer-Weber growth mode at high temperature.

• International Journal of Human Ecology
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• v.16 no.1
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• pp.11-23
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• 2015

Although Korean international students/scholars are among the largest groups of international students/scholars on most campuses in the United States, little is known about what types of demands their families face and how they adapt successfully in the face of demands. The purpose of this study was to explore family resilience, which consists of family demands, capabilities, and adaptation, perceived by Korean international student/scholar families, being theoretically guided by the Family Adjustment and Adaptation Response (FAAR) model. Data were collected through face-to-face interviews with couple informants. Following procedures of theory-based content analysis, data were analyzed using key FAAR concepts. Findings showed that most informants reported normative types of family demands such as hardships due to childcare; primary family capabilities were "maintaining social integration," "affective and instrumental communication," and "family cohesiveness," and "nurturance, education, and socialization" was the primary family adaptation mode. New categories under family capabilities, "religious commitment" and "transnational family support" were developed. The results suggest that there is a unique set of family capabilities that contribute to the successful adaptation of Korean international student/scholar families. Implications and limitations are discussed.

• Journal of the Korean Institute of Landscape Architecture
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• v.28 no.1
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• pp.19-28
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• 2000

The purposes of this study are two folds: a) to introduce conjoint choice model to research the choice behavior of theme park users, and b) to suggest the strategies to strengthen the competitiveness of theme parks. The major four theme parks in Seoul metropolitan areas were selected as study areas. A leading polling agency was employed to select 432 respondents by probability sampling and to conduct face-to-face interview. Both alternative generating and choice set generating fractional factorial design were conducted simultaneously to meet the necessary and sufficient conditions for calibration of the conjoint choice model. Dummy coding was used to represent the attribute levels, and the alternative-specific model was calibrated. The goodness-of-fit of the model was quite satisfactory($\rho$$^2$=0.47950), and most parameters values had to expected sign and magnitude. Car was preferred transport mode to shuttle bus for visiting theme parks ; however the most ideal attribute levels only were estimated significantly. Most attribute levels of shuttle bus were estimated significantly except the Dream Land, which is the least attractive park among study areas. Simulation results showed that the shuttle bus was a mode worth providing to switch the current car dominant visiting pattern of theme parks, which will be one the effective strategies to attract more patrons, especially for potential users adjacent to parks. Several ideals were suggested for future researches, in terms of utilization of more general utility function and new base alternative, and inclusion of more salient attributes such as constraints in the model.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.4
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• pp.30-37
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• 1997

This thesis is concerned with the study on the characteristics of the tool failure occuring at the beginning of cutting in finish machining of hardened steels such as carbon tool steel and alloy tool steel by a ceramic tool (Al$_{2}$O$_{3}$+TiC) with nose radius. In the machining of hardened carbon steel STC3, the wear mechanism on the flank face of the ceramic tool is abrasion wear. The mode of tool failure is developed into catastropic fracture with flaking. It is thought that the fracture caused by FeO and TiO$_{2}$ results from the oxidation of Fe in the workpice and TiC in the ceramic tool and the deposit of Fe formed on the surface of the ceramic tool. In the machining of hardened alloy steel STD11, the wear mechanism on the flank face of the ceramic tool is that abrasion and adhesion wear exist simultaneously. The mode of tool failure at the beginning of cutting features is DOC notch wear. It is thought that the DOC notch wear caused by FeO and TiO$_{2}$results from the oxidation of Fe and TiC in the workpiece and ceramic tool, respectively.

• International Journal of Railway
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• v.5 no.2
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• pp.71-76
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• 2012

Recently, axle load, operating speed and traffic density on railroads have had a tendency to increase and thereby cause additional pressure applied on used track. These operating conditions frequently result in service failure due to wear caused by wheel-rail contact and fatigue damage under cyclic loading. Among rail defects, the transverse crack, which has been the most dangerous type of fatigue damages, is developed from the subsurface crack near the rail running face and grows perpendicular to the rail surface. Therefore, it is necessary to investigate systematically the growth behavior of transverse crack for rail steel under mixed mode. In this study, the fatigue crack growth behavior of the transverse crack in rail steel was experimentally investigated under mixed-mode variable amplitude loadings.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1998.10a
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• pp.150-155
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• 1998

Sliding mode control is a powerful control methodology for the control of uncertain systems. However, it and its variations have some disadvantages such as chattering and imprecise tracing performance. A novel scheme of the sliding mode control is presented for the accurate tracking control of the uncertain systems. The fuzzy logic-baced control law maintaining stability and consistent performance in the face of modeling imprecise is derived and simulation results showing its effectiveness are presented.

• Proceedings of the KIEE Conference
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• 2007.11a
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• pp.96-97
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• 2007

A stator of ultrasonic motor of high torque with a new configuration is proposed. The stator designed newly is two sided vibrator consisting of toothed metal disk with piezoelectric ceramic ring bonded on both face of disk. which generates a flexural traveling wave along the circumference of disk. it produces a large vibrating force and amplitude because the vibrator is sandwiched by two piezoelectric ring. The finite element method was used to compute the vibration mode of the stator with a outer diameter of 48mm. A 6th vibration mode was chosen as operation mode with resonance frequency about 72kHz. According to the design, the prototype stator was fabricated and its performance was measured.