• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1307-1311
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• 2007

Three-dimensional transient keyhole profile is numerically analyzed for the case of stationary laser keyhole welding. Volume of fluid (VOF) method is adopted to track the free surface of molten metal based on the three governing equations which are continuity, momentum and energy equations. Multiple reflections of laser beam at the keyhole walls are also included in analysis through a real-time ray tracing technique. In this simulation, especially, polarization of laser is considered as an energy absorption mechanism following the Fresnel reflection theory. Both cases of linearly and circularly polarized beam are simulated and compared. The results show that the theoretically generated keyhole is asymmetrically stretched along the direction of polarization which is already observed experimentally before.

• Advances in nano research
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• v.2 no.4
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• pp.199-210
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• 2014

Carbon nanotubes have exceptional mechanical, thermal and electrical properties, and are considered for high performance structural and multifunctional composites. In the present study, the natural frequencies of aligned single walled carbon nanotube (CNT) reinforced composite beams are obtained using shear deformable composite beam theories. The Ritz method with algebraic polynomial displacement functions is used to solve the free vibration problem of composite beams. The Mori-Tanaka method is applied to find the composite beam mechanical properties. The continuity conditions are satisfied among the layers by modifying the displacement field. Results are found for different CNT diameters, length to thickness ratio of the composite beam and different boundary conditions. It is found that the use of smaller CNT diameter in the reinforcement element gives higher fundamental frequency for the composite beam.

• Bulletin of the Korean Mathematical Society
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• v.51 no.1
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• pp.221-227
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• 2014

Our goal is to relax a sufficient condition for the exponential almost sure stability of a certain class of stochastic differential equations. Compared to the existing theory, we prove the almost sure stability, replacing Lipschitz continuity and linear growth conditions by the existence of a strong solution of the underlying stochastic differential equation. This result is extendable for the regime-switching system. An explicit example is provided for the illustration purpose.

• Korean Parent-Child Health Journal
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• v.18 no.1
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• pp.39-45
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• 2015

Purpose: This study aimed to analyze the women's health nursing curriculum in Korean nursing baccalaureate education. Methods: This study was conducted with women's health nursing curriculum from one nursing school. Data were collected through one nursing school in A city, Korea from November to December, 2014. Data were analyzed using 4 domain of Posner's curriculum analysis. Results: Curriculum documentation and origins were based on the nursing standard from Korean Accreditation Nursing Board Education and the learning goal of maternal nursing from Korean Nursing Association. The purpose and content of the curriculum were composed with cognitive, affective, and psychomotor domains. The curriculum was organized deductively and multidisciplinary. Conclusion: The continuity, sequence, integration, and articulation were advantage of the curriculum. The concept map of women's health nursing curriculum can contribute to share the objectives between teachers and learners.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.5
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• pp.85-93
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• 1996

The far-zone scattered field patterns of a hyperbolic reflector antenna are analyzed by using uniform geometrical theory of diffraction(UTD). The main objective of this paper is to obtain the higher order diffraction contributions which provide the continuity over the shadow boundaries of the first order solution. to obtain the scattered magnetic field characteristics, the scattered field components of the secodn-order diffraction, diffraction-reflection, diffraction-reflection-diffraction terms are added to the result of the previous research. The results of the present research are compared to those of the first order solution and the method of moments. One can observe the improvemtn of the current approach over the first order solution. also, the results of the present method agree very well with those of the moment methods especially in the transition regions near the first order diffraction shadow boundaries.

• 한국공간정보시스템학회:학술대회논문집
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• 2004.05a
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• pp.190-196
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• 2004

Thick composite laminated plates is considered in 3D finite-element. To consider continuity of transverse stresses and displacement field, mixed finite-element has been developed by using layerwise theory and the minimum potential energy principle. Mixed finite-element has been enforced through the thick direction, Z, of a laminated plate by considering six degree-of-freedoms per node. Six degree-of-freedoms are three displacement components in the coordinate axes directions and three transverse stress components ${\sigma}_z,\;{\tau}_{xz},\;{\tau}_{yz}$. The model maintain the fundamental elasticity relations that are stress-strain relation and displacement-strain relation, because the transverse stress components invoked as nodal degrees of freedom by using the fundamental elasticity relationship between th components of stress and displacement. Random vibration analysis of the model is performed by computing consistent mass matrix and computing covariance in frequency domain technique.

• Steel and Composite Structures
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• v.24 no.5
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• pp.537-548
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• 2017

In this paper presents bending characteristic of single wall carbon nanotube reinforced functionally graded composite (SWCNTRC-FG) plates. The finite element implementation of bending analysis of laminated composite plate via well-established higher order shear deformation theory (HSDT). A seven degree of freedom and $C^0$ continuity finite element model using eight noded isoperimetric elements is developed for precise computation of deflection and stresses of SWCNTRC plate subjected to sinusoidal transverse load. The finite element implementation is carried out through a finite element code developed in MATLAB. The results obtained by present approach are compared with the results available in the literatures. The effective material properties of the laminated SWCNTRC plate are used by Mori-Tanaka method. Numerical results have been obtained with different parameters, width-to-thickness ratio (a/h), stress distribution profile along thickness direction, different SWCNTRC-FG plate, boundary condition, through the thickness (z/h) ratio, volume fraction of SWCNT.

• Korean Journal of Child Studies
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• v.13 no.1
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• pp.125-138
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• 1992

The purpose of the present study was to examine the development of embedding through relative clause formation in the first language acquisition of Korean. Results are reported from the study of the spantaneous natural speech of 36 young Korean children ranging from 16 months to 45 months in age acquiring Korean as their first language in Chinju, Korea. The results revealed a developmental order in the first language acquisition of Korean relative clause structures. Namely, a free or headless relative clause appears to be acquired first, before lexically headed restrictive relative construction. This order is consistent with one evidenced in English (and also Chinese) first language acquisition, 'free' relatives appear to provide a developmentally early stage in the acquisition of restrictive relative clauses. The Korean data provided additional evidence for an intermediary stage with an overt complementizer as well as an overt lexical head. Implications for the results are disscused with regard to a continuous theory of universal grammar in the first language acquisition.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2003.05a
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• pp.231-239
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• 2003

A Digital Wave Tank simulation technique based on a finite-difference method and a modified marker-and-cell (MAC) algorithm is applied to investigate the characteristics of nonlinear Tsunami propagations and their interactions with a 2D sloping beach and Ohkushiri island, and to predict maximum wave run-up around the island. The Navier-Stokes (NS) and continuity equation are governed in the computational domain and the boundary values updated at each time step by a finite-difference time-marching scheme in the frame of rectangular coordinate system. The fully nonlinear kinematic free-surface condition is satisfied by the modified marker-density function technique. The Nearshore Tsunami is assumed to be a solitary wave and generated from the numerical wavemaker in the developed Digital Wave Tank. The simulation results are compared with the experiments and other numerical methods based on the shallow-water wave theory.

• Korean Institute of Interior Design Journal
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• v.21 no.5
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• pp.77-84
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• 2012

Single formative language created by the standardization of industrial society carries a cell constructive aspect. Such space structural form made gigantic buildings, which has a symbolism as an independent object. Such space shows a morphological symbolism by public preference but it did not establish essential meaning of a shape or concentrated relation. In this regard, this paper tries to show organic similarity of structural formality of small commercial space (patterned space), which was made by the continuity of concentrated patterns not an object of dualistic unit features. Therefore, this study analyzed the cultural, commercial and public space based upon systematical concept and features. Systematical space formality that makes multilateral relation between human, environment and a thing is a concentrated view point by relational features not by the cluster displayed by hierarchical features. Systematical space of small patterned space emphasized its appropriateness of expansion and creating diversified spaces unlike gigantic symbolic buildings.