• Proceedings of the Computational Structural Engineering Institute Conference
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• 1993.04a
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• pp.117-124
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• 1993

The Neumann Expansion method has been used for evaluating the response variability of three dimensional truss structure resulting from the spatial variability of material properties with the aid of the finite element method, and in conjunction with the direct Monte Carlo simulation methods. The spatial variabilites are modeled as three-dimensional stochastic field. Yamazaki 〔1〕 has extended the Neumann Expansion method to the plane-strain problem to obtain the response variability of 2 dimensional stochastic systems. This paper presents the extension of the Neumann Expansion method to 3 dimensional stochastic systems. The results by the NEM are compared with those by the deterministic finite element analysis and by the direct Monte Carlo simulation method

• Hwankyungkyoyuk
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• v.22 no.3
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• pp.72-82
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• 2009

The purpose of this study was to develope experience-education program for elementary students which use environmental resources and learning sources of Jeju island. This study designed developing framework of environmental education program for using local resources and developed experience-education program on the basis of it. Especially this program consisted of direct experience, indirect experience, and local community learning. This program consisted of five activities -'Jeju's water', 'Mecca of wind power', 'Rushing jellyfish', 'Ramsar wetland', and 'Searching the fossil'. Each activity themes was to use environmental resources of Jeju island. And this program had relationship with science, social studies, and ethics in the curriculum. The result of this study will serve to activate environmental education program for using local resources if we solve program's problem through application process.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.9 no.4
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• pp.517-526
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• 1997

This study is focused on the development and selection of the optimal cool tube system to maximize its thermal performance. Cool tube is devised to reduce the heating and cooling load of building by preheating or refreshing of intake air with buried pipes. Finite volume method is adopted to solve the conduction problem between the cool tube and earth. We examine the cool tube system for two operating periods, a short term(12 hours) and a long term(3 months). The results of short term operations reveal that condensation significantly influences and raises the exit air temperature. For long term operations, optimum conditions of cool tube system are obtained with variations of flow-rate, depth, length and diameter of cool tube.

• KIEAE Journal
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• v.14 no.5
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• pp.67-73
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• 2014

This study aims at examining kinetic efficient shading systems and their implementation methods. These days, the importance of the shading devices are getting more significant due to the energy problem. Cordially, suitable shade designs are required as an important element for the exterior envelope of the building. This study employs the optimal shading design as an efficient shading method with the kinetic system that can be converted actively by the altitude of the sun. The proposed kinetic shading system works not only as a lightshelf in case the altitude of the sun is high but also as a vertical louver when the sun is getting lower in order to block the direct sunlight. This study has analyzed the thermal performance and shading coefficient of the kinetic shading system in comparison to existing fixed shading devices using the Ecotect. The results, in sum, conclude that the suggested kinetic shading system could decrease direct sunlights 26.2% more than the existing shading methods.

• Journal of Mechanical Science and Technology
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• v.15 no.11
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• pp.1572-1579
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• 2001

We investigate the possibility of application of the Goore Scheme to turbulence control for drag reduction. In Part I, we examine the performance of the original Goore Scheme by applying it to a si mple one-dimensional problem. For the application of the scheme to turbulence control, we extend the scheme's capability so that it can treat multi-dimensional problems and examine its validity theoretically. The convergence of the extended scheme with a dynamic memory is faster by an order of magnitude than the original scheme. In Part II, we apply the proposed scheme to reduce drag for turbulent channel flows through direct numerical simulation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.9B
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• pp.791-798
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• 2004

In case of failure in the IP network, services should be provided via a backup path which fully meets QoS requirements. In this regard, we in this paper suggest simple-PFC(s-PFC) to restore single link failure, iterative-PFC(i-PFC) for multiple link failures, and fault_node Avoidance-PFC(a-PFC) for failures of nodes such as routers. Taking the minimum cost rerouting problem into account, we compare and analyze performance of those three mechanisms carrying out Direct-destination Rerouting(DR).

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.1
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• pp.48-53
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• 2000

The novel integration method with programmable high-pass filter is suggested in order to solve the problem of integration for stator flux estimation in a stator flux oriented direct vector controlled induction motor drive system. The dc offset in a pure integrator is eliminated using high-pass filter with fixed time constant, and then time constant of programmable high-pass filter is controlled with a inverter frequency for integration in a wide frequency range, considering phase lag and attenuation due to both the hardware low-pass filter and high-pass filter. The proposed method is verified with the experimental results implemented by 32-bit DSP.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.10
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• pp.149-156
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• 2010

In this paper, the optimal design of a wind generator, implemented with the hybridized GA(Genetic Algorithm) and ES(Expert System), has been performed to maximize the AEP(Annual Energy Production) over the whole wind speed characterized by the statistical model of wind speed distribution. In particular, to solve the problem of calculation iterate, ES finds the superior individual and apply to initial generation of GA and it makes reduction of search domain. Meanwhile, for effective searching in reduced search domain, it propose Intelligent GA algorithm. Also, it shows the results of optimized model 500[kW] wind generator using hybridized algorithm and benchmark result of compare with GA.

• Proceedings of the KIEE Conference
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• 1993.07a
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• pp.373-375
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• 1993

In this paper we deal with the design and implementation problem of a robust adaptive controller for a direct drive manipulator with unmodeled dynamics. The proposed controller ensures that the closed loop system is stable and output errors are converged to some boundary. To validate the improved performance of the proposed controller experimental results are presented in this paper.

• Nuclear Engineering and Technology
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• v.49 no.6
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• pp.1189-1198
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• 2017

Computer-aided design (CAD)-based Monte Carlo radiation transport is of value to the nuclear engineering community for its ability to conduct transport on high-fidelity models of nuclear systems, but it is more computationally expensive than native geometry representations. This work describes the adaptation of a rendering data structure, the signed distance field, as a geometric query tool for accelerating CAD-based transport in the direct-accelerated geometry Monte Carlo toolkit. Demonstrations of its effectiveness are shown for several problems. The beginnings of a predictive model for the data structure's utilization based on various problem parameters is also introduced.