• International Area Studies Review
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• v.13 no.3
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• pp.309-330
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• 2009

This paper analyzes comparatively the effects of changes in real effective exchange rates on the business fluctuations of the cases of Korea and Japan employing structural vector auto-regression(S-VAR) model which uses quarterly data for the five variables of real effective exchange rates, GDP gap, real interest rates, oil prices, inflation rates for the period of 1980-2006. The paper employes impulse-response analysis and variance decompositions. The paper finds that real exchange rate depreciations are contractionay for the case of Korea while they are expansionary for the case of Japan. These results are consistent with the prevailing empirical results that real exchange rate depreciations are contractionary for developing countries while expansionary for advanced countries.

• Journal of Korean Society of Steel Construction
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• v.13 no.5
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• pp.587-597
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• 2001

The structural system that discreterized continuous shells is frequently used to make dome-type structures and these structures show the unstable phenomena by snap-through or bifurcation when a load level reaches certain critical value. The characteristic structural behaviour of a cable dome shows a strong nonlinearity and very sensitive according to the initial imperfection. In this study the shape finding problem by applying initial tension stress is investigated and using this the unstable phenomena of perfectly shaped and initially imperfected shape model by external forces are examined to grasp the unstable behavior of cable dome using the Geiger-type model.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.14-24
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• 2018

Several typical hyper-elastic constitutive models that encompass both conventional and advanced ones were investigated for the application of instability problems, including the biaxial tension of a rubber patch and inflation of spherical or cylindrical balloons. The material models included the neo-Hookean model, Mooney-Rivlin model, Gent model, Arruda-Boyce model, Fung model, and Pucci-Saccomandi model. Analyses can be done using membrane equations with particular strain energy density functions. Among the typical strain energy density functions, Kearsley's bifurcation for the Treloar's patch occurs only with the Mooney-Rivlin model. The inflation equation is so generalized that a spherical balloon and tube balloons can be taken into account. From the analyses, the critical material parameters and limit points were identified for material models in terms of the non-dimensional pressure and inflation volume ratio. The bifurcation was then identified and found for each material model of a balloon. When the finite element method was used for the structural instability problems of rubber-like materials, some careful treatments required could be suggested. Overall, care must be taken not only with the analysis technique, but also in selecting constitutive models, particularly the instabilities.

• Proceedings of The KACE
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• 2018.01a
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• pp.79-82
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• 2018

최근 유치원생과 초등학교 저학년생을 대상으로 프로그래밍 경험을 제공하기 위한 목적으로 다양한 텐저블 프로그래밍 도구들이 개발되고 있다. 개발된 텐저블 프로그래밍 도구들은 순차, 분기, 반복 등의 프로그래밍 개념을 손으로 조립하거나 쌓는 등의 구체적인 조작을 통해 프로그래밍 활동을 체험하도록 설계되었다. 하지만, 텐저블 프그래밍 도구가 순차, 반복, 분기, 변수, 함수 등의 프로그래밍의 개념을 일부만 반영하고 있어 프로그래밍 개념에 대한 체험이 완전하게 이루어지지 않고 있다. 본 연구는 기존에 개발한 텐저블 프로그래밍 도구인 B-Bricks에 조건에 따른 분기와 반복 개념을 추가하여 설계하는 연구로, B-Bricks를 사용하여 조건문과 반복문을 설계하였다.

• Journal of Software Engineering Society
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• v.25 no.3
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• pp.59-62
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• 2012

We propose a novel metric for quantitatively comparing different clustered results generated from software clustering algorithms. A quantitative evaluation of software clustering helps understanding of architectural changes of software. The concept of split, which has been used for analysis of genetic characters in bio-informatics, is applied in the analysis of software architecture.

• The Korean Journal of Applied Statistics
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• v.22 no.1
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• pp.75-88
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• 2009

Gross Regional Domestic Product (GRDP) is regarded as an essential information to understand regional economy. However, GRDP is hardly used for establishment of regional economic plan and related statistical research due to its late and yearly publication. Therefore, it is necessary to estimate quarterly GRDP to grasp the current regional economy faster In this study, considering the comovement between GDP and GRDP for the same industry, reference series are made. Quarterly GRDP is estimated the following two steps; First, preliminary quarterly GRDP is estimated using Chow-Lin's method based on the reference series to eliminate temporal discrepancies. Second, preliminary quarterly GRDP is adjusted using Denton's multivariate method to eliminate contemporaneous discrepancies.

• Journal of Korean Association for Spatial Structures
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• v.4 no.3 s.13
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• pp.103-109
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• 2004

The lowest load when the equilibrium condition becomes to be unstable is defined as the buckling load. The primary objective of this paper is to be analyse stability boundaries for star dome under combined loads and is to investigate the iteration diagram under the independent loading parameter. In numerical procedure of the geometrically nonlinear problems, Arc Length Method and Newton-Raphson iteration method is used to find accurate critical point(bifurcation point and limit point). In this paper independent loading vector is combined as proportional value and star dome was used as numerical analysis model to find stability boundary among load parameters and many other models as multi-star dome and arch were studied. Through this study we can find the type of buckling mode and the value of buckling load.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.28 no.3
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• pp.309-316
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• 2015

A state-based peridynamic model is able to describe a general constitutive model from the standard continuum theory. The response of a material at a point is dependent on the deformation of all bonds connected to the point within the nonlocal horizon region. Therefore, the state-based peridynamic model permits both the volume and shear changes of the material which is promising to reproduce the complicated dynamic brittle fracture phenomena, such as crack branching, secondary cracks, cascade cracks, crack coalescence, etc. In this paper, the two-dimensional state-based peridynamic model for a linear elastic plane stress solid is employed. The damage model incorporates the energy release rate and the peridynamic energy potential. For brittle glass materials, the impact of the crack-parallel compressive stress waves on the crack branching pattern is investigated. The peridynamic solution for this problem captures the main features, observed experimentally, of dynamic crack propagation and branching. Cascade cracks under strong tensile loading and secondary cracks are also well reproduced with the state-based peridynamic simulations.

• Journal of KIISE:Computer Systems and Theory
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• v.28 no.12
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• pp.685-697
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• 2001

Cache memories are small fast memories used to temporarily hold the contents of main memory that are likely to be referenced by processors so as to reduce instruction and data access time. In this paper, we represent analytical models of instruction fetch process for four types of instruction cache structures that can be used for superscalar processors. In the models, we define various kinds of architectural parameters and take cache miss and branch misprediction into consideration. To prove the correctness of the proposed models, we performed extensive simulations and compared the results with the analytical models. Simulation results showed that the proposed model can estimate the instruction fetch rate accurately within 10% error in most cases. Both analytical model and simulation show that the increase of cache misses reduces the instruction fetch rate more severely than that of branch misprediction does. However, the analytical model can explain the causes of performance degradation which cannot be uncovered by the simulation method only. The model is also able to provide exact relationship between cache miss and branch misprediction for instruction fetch analysis.

• Journal of the Korean Society for Railway
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• v.18 no.3
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• pp.175-185
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• 2015

Generally, in the train area, switch tracks have required high reliability because this system is directly associated with derailment. Especially, switch tracks of Maglev vehicles must be moved in terms of the whole geometric characteristics, in which the bogies are encased in the switch track. For this reason, switch track was constructed with steel lighter than concrete girders. But, the steel switch track was weak because of structural vibration as well as structural deformation. Therefore, it is important to predict the levitation stability when a vehicle passes over flexible switch track. The aims of this paper are to develop a coupled dynamic model to describe the relationship between a Maglev vehicle and switch track and to predict the levitation stability. In order to develop the coupled dynamic model, a three dimensional vehicle model was developed based on multibody dynamics; a switch model was made using the modal superposition method. And, the developed model was verified using comparison measured data.