• Wind and Structures
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• v.12 no.2
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• pp.103-120
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• 2009

Articulated tower platforms due to its compliant nature are more susceptible to the dynamic effects of wind than conventional fixed platforms. Dynamic response analysis of a double hinged articulated tower excited by low frequency wind forces with random waves is presented in this paper. The exposed super structure of the platform, housing the drilling and production facilities is subjected to mean and fluctuating wind loads, while the submerged portion is acted upon by wind driven waves. The fluctuating component of the wind velocity is modeled by Emil Simiu's spectrum, while the sea state is characterized by Pierson-Moskowitz spectrum. Nonlinearities in the system due to drag force, added mass, variable submergence and instantaneous tower orientation are considered in the analysis. To account for these nonlinearities, an implicit time integration scheme (Newmark's-${\beta}$) has been employed which solves the equation of motion in an iterative fashion and response time histories are obtained. The power spectra obtained from random response time histories show the significance of low frequency responses.

• Hwankyungkyoyuk
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• v.20 no.3
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• pp.125-133
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• 2007

The purpose of this study is to improve environmental education policy through analysing environmental education policy in Seoul. According to the results, it should be considered in suggesting improvement of Environmental Education policy in Seoul as follows. First, according to the analyses of paradigm of environmental education policy, it does not in part depend on implication of education for sustainable development. Second, according to the analyses of driving force on the environmental education policy, The state of integration between formal education and non formal education has not been mature yet. Third, according to the current state on the environmental education policy, it is urgent to strategic approach to activate school environmental education. Consequently, It is necessary to indicate a new paradigm shifts for review and revisions of policy and practice in support of sustainable regional development in Seoul. It is also desirable to provide new infra structure which included basic framework, guideline, practical programme so as to enhance environmental education. Thus it would be possible to contribute to activating education for sustainable development.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1995.03a
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• pp.196-202
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• 1995

Drawbead formulation is the first process together with a binder wrap process in a sheet metal forming process. The purpose of a drawbead is to control the flow of the metal into the die in panel press forming. To simulate the drawbead formation process, an elasto-plastic finite element formulation is derived from the equilibrium equation an drelated boundary conditions considering the proper contact conditons. The developed finite element program is applied to drawbead formation in the plane strain condition. The simulation of drawbead formation produces the distribution fo stress and strain along the bead and the resultant elongation of the sheet in the cavity region with respect to various cavity dimensions of the sheet as well as the punch force of a drawbead and the amount of draw-in with respect to the stroke fo a drawbead. The numerical resutls provides the fundamental information as a boundary condition to analyze the complex binder wrap phenomena and panel press forming in simple way.

• Steel and Composite Structures
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• v.25 no.5
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• pp.557-569
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• 2017

Moment-thrust-curvatures ($M-P-{\Phi}$ curves) are fundamental quantities for detailed descriptions of basic properties such as stiffness and strength of a section under axial loads required for accurate computation of the deformations of reinforced concrete or composite columns. Currently, the finite-element-based methods adopting small fibers for analyzing a section are commonly used for generating the $M-P-{\Phi}$ curves and they require large amounts of computational time and effort. Further, the conventional numerical procedure using the force-control method might encounter divergence problems under high compression or tension. Therefore, this paper proposes a divergence-free approach, combining the use of the displacement-control and the Quasi-Newton scheme in the incremental-iterative procedure, for generating the $M-P-{\Phi}$ curves of arbitrary sections. An efficient method for computing the strength from concrete components is employed, where the stress integration is executed by layer-based algorithms. For easy modeling of residual stress, cross sections of structural steel components are meshed into fibers for strength resultants. The numerical procedure is elaborated in detail with flowcharts. Finally, extensive validating examples from previously published research are given for verifying the accuracy of the proposed method.

• Fashion & Textile Research Journal
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• v.19 no.4
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• pp.373-384
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• 2017

This research has its significance on contributing to the establishment of sustainable fashion industry ecosystem of Seongsu area based on the creativity which is the driving force of economic growth in the 21st century. This study reviewed the major activities and processes of Seongsu-dong's regional specialized industries project and the social economic organizations's creation of fashion clusters by using specialized books, previous research, press releases such as newspapers, magazines, and the specialized internet site(www.seoul.go.kr). Also street casual-style clothes were designed based on work-wear that themed Seongsu-dong's industrial scene and social problems. The results of this study are as follows. Seongsu-dong represents the political and economic characteristics of a typical semi-industrial area in which the automobile repair, printing, textile, leather, and handmade industries are concentrated in accordance with the government's business and policy, and shows the technical characteristics through the internal complete industrial ecosystem integration of the handmade industries. In addition, social and cultural characteristics such as various local activities based on creativity are shown by social enterprises, and cultural artists. Based on the results of analyzing the regional characteristics of Seongsu-dong according to political, economic, technological, socio-cultural characteristics, eight fashion designs were made as motifs reflecting the regional characteristics of Seongsu-dong.

• Structural Engineering and Mechanics
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• v.64 no.4
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• pp.515-526
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• 2017

Dynamic response of functionally graded Carbon nanotubes (FG-CNT) reinforced pipes conveying viscous fluid under accelerated moving load is presented. The mixture rule is used for obtaining the material properties of nano-composite pipe. The radial force induced by viscous fluid is calculated by Navier-Stokes equation. The material properties of pipe are considered temperature-dependent. The structure is simulated by Reddy higher-order shear deformation shell theory and the corresponding motion equations are derived by Hamilton's principal. Differential quadrature (DQ) method and the Integral Quadrature (IQ) are applied for analogizing the motion equations and then the Newmark time integration scheme is used for obtaining the dynamic response of structure. The effects of different parameters such as boundary conditions, geometrical parameters, velocity and acceleration of moving load, CNT volume percent and distribution type are shown on the dynamic response of pipe. Results indicate that increasing CNTs leads to decrease in transient deflection of structure. In accelerated motion of the moving load, the maximum displacement is occurred later with respect to decelerated motion of moving load.

• Proceedings of the KSME Conference
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• 2000.11a
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• pp.510-515
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• 2000

Dynamic stability of a flying structure undertaking constant and pulsating axial forces is investigated in this paper. The equations of motion of the structure, which is idealized as a free-free beam, are derived by using the hybrid variable method and the assumed mode method. The structural system includes a directional control unit to obtain the directional stability. The analysis model presented in this paper considers the nonlinear effect due to rigid body motion of the beam. Dynamic stability of the system is influenced by the nonlinear effect. In order to examine the nonlinear effect, first the unstable regions of the linear system are obtained by using the method based upon Floquet's theory, and dynamic responses of the nonlinear system in the unstable region are obtained by using direct time integration method. Dynamic stability of the nonlinear system is determined by the obtained dynamic responses.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.421.1-421.1
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• 2014

Top-down processes based on photolithography technology have been developed by using light sources with short wavelength, however, the processes are expected to meet their limits in higher integration of semiconductor integrated circuits. To overcome the limits, researches on bottom-up processes have been proceeded. One of those, fabrication of nanodevices by using nanoparticles has been on research. But it is difficult to align nanoparticles at appropriate positions. To resolve this, studies has been proceeded to form nanowires by bonding DNA molecules which have self-assembly property and positive-charged functionalized gold nanoparticles. There are negative-charged phosphates in backbones of DNA molecules. By using the attractive force between the negative charge of the phosphates and the positive charge of gold nanoparticles, the Au-DNA nanowires are made. However, bonding Au nanoparticles only on DNA molecules, not other nanoparticles, is to be solved. So we studied to resolve this problem. In the formation of Au nanoparticles, we changed the charge of Au nanoparticles by adding HCl to control pH of the functionalized nanoparticles, measured zeta potential. Then we bonded the nanoparticles and DNA molecules and made observation by using FE-SEM and AFM.

• The KIPS Transactions:PartD
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• v.13D no.4 s.107
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• pp.625-632
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• 2006

A Datawarehouse, which extracts and saves the massive analysis data from the operating servers, is a decision support tool in which data quality and processing time are very important. Thus, it is necessary to standardize and improve datawarehouse development process in order to stabilize data quality and improve the productivity. We propose a novel improved process for datawarehouse development by applying the configuration management of CMMI (Capability Maturity Model Integration) which has become a major force in software development process improvement. In addition, we specify some matrices for evaluating datawarehouse development process. Through the comparison analysis with other existing processes, we show that our proposal is more efficient in cost and productivity as well as improves data quality and reusability.

• Journal of Navigation and Port Research
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• v.42 no.5
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• pp.347-356
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• 2018

The presence of the Fourth Industrial Revolution is omniscient, led by full force emergence of technologies that make biological, physical, and digital worlds borderless. All industries which jump on the bandwagon, can observe convergence and merging of bushiness happening within, between and across industries. As the shipping and port logistics industry is said to be in eye of this storm, the purpose of this study is to investigate the shipping and port logistics industry's awareness regarding 4th IR, as well to identify necessary countermeasures in responding to progression of this trend. Analytic Hierarchy Process (AHP) methodology was then used to compare the importance of four phases of countermeasures, reviewed by experts in the field. Results showed that countermeasures should be first orchestrated to the 'Merging and Integration of Inter-industry', then followed by 'P reemptive Introduction of Advanced Technology', 'Expansion of Intra-industry Businesses', and eventually 'Automation, Unmanned Technology'. Last but not least, four phases of countermeasures which should be introduced and executed one phase after another, are outlined for the shipping and port logistics industry to boost its competitiveness in addressing this progressive trend.