• KSCE Journal of Civil and Environmental Engineering Research
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• v.11 no.4
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• pp.27-35
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• 1991

This paper presents a numerical analysis procedure and a characteristics for vibration and buckling of the cylinderical panels. The panels with simply-simply or simply-clamped edge supports are subjectes to circumferential compressive or flexural stresses. The differential equations governing vibration and buckling for these panels are derived by using the fundamental differential equation of the Love-Timoshenko and are solved numerically via the Galerkin method. The panel with simply-clamped edge supports is used a trigonometric function or a eigen function of a beam as a trial function and the effects of trial functions on numerical solutions are displayed. Numerical results are presented to demonstrate the effects of the flexural parameters in natural frequencies and coefficients of critical buckling and some typical mode shapes of vibration and buckling are also presented.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.31 no.7 s.262
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• pp.581-587
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• 2007

At present time, LNG demand of the world is increasing and the piping line for NG transportation has been already installed in Korea. The air fm vaporizer is, however, required because of the transportation for remotely local areas. This paper numerically investigates on the heat transfer characteristics of relevant geometric variations of air-fin vaporizer which is heated by air not by sea water. This vaporizer must be designed in consideration of both efficiency and economics because air is relatively a little heat source. In this study, the pipe and the longitudinal fins are fundamental geometric considerations. Main parameters of geometry are the number, the thickness, and the length of the fins. Finally, the results of heat transfer effects are investigated with the characteristics of each parameter variation.

• Journal of Fashion Business
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• v.19 no.6
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• pp.28-41
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• 2015

Properties of textile fabrics influence the appearance, aesthetics, and performance of garment. Drape and related properties of fabrics affect profoundly the static and dynamic appearance during wearer's movement. The three dimensional shape of the folded structure often deforms with time or with subtle vibration around the fabric specimen during the drape measurement. Due to the uneven and complex nature of fabrics, the overall shape of the fabric specimen on the drape tester often becomes unstable. There is a need to understand the fundamental mechanisms of how draping may generate pleasing forms. Two drape test methods, conventional Cusick drape test, and in-built drape tester, based on a depth camera, are compared. Fabric specimens including cotton, linen, silk, wool, polyester, and rayon are investigated for the fabric drape and other physical/mechanical parameters. Drape coefficient values of fabric specimens are compared based on the final drape images, together with the intermediate 3D drape images of the specimens during elevation process of the drape tester equipped with a stepper motor system. The correlation coefficient between the data based on the two methods is reasonably high. Another advantage from the depth camera system is that it allows further analysis of three-dimensional information regarding the fabric drape shape, including the shape of nodes or crest and trough.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.1
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• pp.41-47
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• 2012

The LDS(Laser Direct Structuring) is one of the new direct writing methods to fabricate conductive patterns by energy beam. It uses thermoplastic polymers with an additive compound that serves as plating seed after the activation by laser. The advantages of LDS include the miniaturization of electrical components, design flexibility, and a reduced number of production steps. The purpose of this study is to investigate the fundamental mechanism for LDS and the characteristics of conductive patterns by laser parameters. These results were studied by SEM, EDX, and XPS analysis. We have used a 20W pulse-modulated fiber laser and copper electroless plating to fabricate conductive patterns on polymer. The result showed that electroless copper plating seed caused the laser cracking of additive compound. In particular, the additive compound contained in copper metal oxides atoms will be changed to copper metal elements. Also, the characteristics of conductive patterns were dependent on laser parameter, especially laser fluence.

• Korean Journal of Remote Sensing
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• v.29 no.3
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• pp.293-306
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• 2013

Hydrometeor type and Drop Size Distribution (DSD) in cloud are the fundamental properties that may help explain the rain formation processes and determine the parameters of radar meteorology. This study presents a preliminary analysis of hydrometeor types and DSD data of cloud measured with a PARSIVEL (PARticle SIze and VELocity) optical disdrometer at the site of Cloud Physics Observation System (CPOS, $37^{\circ}41^{\prime}N$, $128^{\circ}45^{\prime}E$, 843 m from sea level) in Daegwallyeong mountainside of Korea. The method has been validated by comparing the observed rainfall rates with the computed ones from the fitted distribution, using the physical data such as DSD, terminal velocity, and rain intensity which were measured by a Micro-Rain Radar (MRR) and a PARSIVEL optical disdrometer. The analysis period started in three cases: on rainy days with light rain (15.5 mm), moderate rain (76 mm), and heavy rain (121 mm), from March to November 2007, respectively.

• Journal of Korea Water Resources Association
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• v.32 no.1
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• pp.49-59
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• 1999

In order to understand the present situation of bridge scouring and to provide the fundamental information for bridge design, in-situ measured data is analyzed for bridge scours at small and medium streams in the heartland of Korea. The physical parameters affecting the bridge scouring such as flow depth, velocity, pier length and width, scouring depth, and the angle between flow and pier are extensively surveyed and measured. According to the locality and the pier type data are classified to analyze. With these data, some important factors for the scour depth such as flow depth, angle and Froude number are investigated and applied to existing formulas proposed by many researchers. In addition, the computational results are compared with the measured and some of the applicable formulas in this region are recommended.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1548-1549
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• 2011

High voltage cryogenic insulation issues need to be addressed in order to promote the commercialization of high temperature superconducting (HTS) equipment. As a fundamental step in the development of the optimum bushings for HTS devices, the breakdown characteristics of liquid nitrogen mixed with liquefied insulating gases such as $N_2$, $SF_6$, and $CF_4$ have been investigated. In order to investigate the possibility of substituting $CF_4$ gas for $SF_6$ gas for the bushings of HTS electrical equipment, AC withstanding voltage tests have been performed. In this paper, finding the maximum electric field $E_{max}$ using utilization factor ${\eta}$. This result is applicable to developing the real scale HTS equipment of the design parameters.

• Journal of the Korean Mathematical Society
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• v.52 no.6
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• pp.1253-1270
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• 2015

Let (R, m) be a commutative Noetherian local domain, M a non-zero finitely generated R-module of dimension n > 0 and I be an ideal of R. In this paper it is shown that if $x_1,{\ldots },x_t$ ($1{\leq}t{\leq}n$) be a sub-set of a system of parameters for M, then the R-module $H^t_{(x_1,{\ldots },x_t)}$(R) is faithful, i.e., Ann $H^t_{(x_1,{\ldots },x_t)}$(R) = 0. Also, it is shown that, if $H^i_I$ (R) = 0 for all i > dim R - dim R/I, then the R-module $H^{dimR-dimR/I}_I(R)$ is faithful. These results provide some partially affirmative answers to the Lynch's conjecture in [10]. Moreover, for an ideal I of an arbitrary Noetherian ring R, we calculate the annihilator of the top local cohomology module $H^1_I(M)$, when $H^i_I(M)=0$ for all integers i > 1. Also, for such ideals we show that the finitely generated R-algebra $D_I(R)$ is a flat R-algebra.

• Journal of the Korean Society of Safety
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• v.33 no.2
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• pp.152-157
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• 2018

The degradation and damage of the components for ballasted track could be caused a serious problem for railway safety. Therefore, the integrity evaluation of ballasted track condition is important to ensure and predict that the track safety and track maintenance. Various track components such as rail pad, ballast, sleeper, and rail that are widely used in Republic of Korea and represent a range of physical properties have been selected for this research. In this study, the experimental modal analysis was performed by the non-destructive testing. Modal test results were obtained from the field test and used to assess the condition of the track components. From the field test, the system of ballasted track was found to be simplified as a two-degree-of-freedom(2DOF) dynamic system. The condition of track component was found to directly affect the dynamic response of ballasted tracks. As the results, the dynamic properties of the track component was depend on the track condition and was distributed more roughly and over a wider range than its initial design values. Further, the methodology presented in this study is possible to determine experimentally the fundamental track parameters which are required in the numerical analysis, and also are useful for the safety assessment of track condition.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.12
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• pp.2943-2948
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• 2015

Run 3D reconstruction using a single camera, based on the information, we are advancing research on driving assistance apparatus or can be informed how to pass the obstacle existing ahead the driver. As a result depth information falls but it is possible to provide information that can pass through an obstacle on the straight. For 3D reconstruction by measuring the internal parameters, it calculates the Fundamental matrix and matching to find the feature points obtained by executing the triangulation on the basis of this. When the through experiments try to confirm the results, the depth information is present error information in the X and Y axes which can determine whether or not to pass through an obstacle has reliability.