• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.9 no.1
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• pp.63-77
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• 2005

The Dirichlet-Neumann problem for the dissipative Helmholtz equation in a connected plane region bounded by closed curves and containing cuts is studied. The Neumann condition is given on the closed curves, while the Dirichlet condition is specified on the cuts. The existence of a classical solution is proved by potential theory. The integral representation of the unique classical solution is obtained. The problem is reduced to the Fredholm equation of the second kind and index zero, which is uniquely solvable. Our results hold for both interior and exterior domains.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.949-953
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• 2004

In this paper, Power Flow Boundary Element Method(PFBEM) is studied as the numerical method for the vibration and sound predictions of complex structures in medium-to-high frequency ranges. NASPFA, the sound analysis software based on PFBEM, is developed and is used for the vibro-acoustic analysis. And also the developed software is used for the prediction of interior and exterior sound fields of vibrating structures and for the analysis of the multi-domain problems. To verify the accuracy, NASPFA is applied to the prediction of the energy distribution in the simple structures, and its results are compared with exact PFA solutions. And various practical vehicle systems are modeled and the distributions of the acoustical energy density are successfully predicted.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1999.10a
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• pp.83-90
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• 1999

This paper presents a method of seismic analysis for a cylindrical liquid storage structure on horizontally layered half-space considering the effects of the interior fluid and exterior soil medium in the frequency domain. the horizontal and rocking motions of the structures are included in this study. The fluid motion is expressed in terms of analytical velocity potential function which can be obtained by solving the boundary value problem including the sloshing behavior of the fluid as well as deformed configuration of the structure. The effect of the fluid is included in the equation of motion as the impulsive added mass and a frequency-dependent convective added mass along the nodes on the wetted boundary with structure. The soil medium is presented using the 3-D axisymmetric finite elements and dynamic infinite elements. The present method can be applied to the structures embedded in ground as well as on ground since it models the soil medium directly as well as the structure. For the purpose of vertification dynamci characteristics of a tank on homogeneous half-space is analyzed. Comparison of the present results with those by others shows good agreement.

• Journal of architectural history
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• v.3 no.2 s.6
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• pp.29-46
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• 1994

The KAMYOUNG is the supreme local government office in CHOSEON dynasty. This study aims to propose the new methodology on research of local government office's prototype in CHOSEON dynasty. Especially this study is the zoning plan of the KAMYOUNG in the late CHOSEON dynasty, It is meant to present the first trial that pursue to total frame of local government in CHOSEON dynasty through the new methodology. The 18th century is the transitional era when the system of norm was deconstructed. The institution and organization of the supreme lacal government office(KAMYOUNG) was united nationwidely and at the same time its deconstruction was carried out in the 18th century. The domain of the governer has fixed in the 18th century, though the scale of 街e KAMYOUNG was enlarged. These domain expressed a strong symbolization according to hierarchy in exterior appearance of the traditional architecture. With the entire execution of a local government coming soon, the concerns about the localization have been increased rapidly. Under this time situation, as the discussion centered on the creation or change of the local self-governing community, so the concerns regarding the traditional aspects of a local government office have been increasing. Hower, without the recognition of this history, as the research of these existing historical materials has been progressed, so the misunderstanding is still left. Especially, because the government office of CHOSEON is a Confucian nation thinking much of a hierarchy based on Yae - Jae, the hierarchy of this architecture has a deep correlation with the organization of an office. The method of this study is like following: Firstly, prescribed characteristic of KAMYOUNG tough syudys of hierarchy in a local government system, human and material composition. secondly, as the changing progress of KAMYOUNG is compared and analyzed with organization of an office in the center. So characteristics of KAMYOUNG are abstracted. And finally, from this, the interpretation methodology of KAMYOUNG is revealed, with a deep correlation between specific characters of organization and architectural structurals. And also, with these methodologies, the interpretation method of the local government office and normative frame in CHOSEON dynasty are suggested.

• Journal of the Korean School Mathematics Society
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• v.16 no.2
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• pp.363-381
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• 2013

The constituents of math learning styles are information recognition and information processing in the cognitive domain and attitudes toward math learning and environments of math learning in the affective domain. Each of the constituents has two opposing styles; there are the visual style and verbal style in information recognition; and there are the whole style and analytical style in information processing. And as for attitudes toward math learning, there are two styles which are the authoritative and goal-oriented style and the practical and entertaining style. Also as for attitudes toward environments of math learning, there are two styles which are the interior-oriented style and exterior-oriented style. There can be classified into 16 types of mathematics learning by the combination of a total of 8 styles of mathematics learning. The purpose of this study was to analyze the preference of the students from three middle schools located in Daegu Metropolitan City to the styles and types of mathematics learning.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.13 no.2
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• pp.231-244
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• 2000

This paper presents a dynamic analysis technique for a 2-D soil-structure interaction problem in the frequency domain, which can directly be applied as an analysis tool for seismic response analyses of underground structures, tunnels, embankments, and so on. In this method, the structure and near-field soil is modeled by the standard finite elements, while the unbounded far-field soil is represented using the dynamic infinite elements in the frequency domain. The earthquake-input motion is regarded as traveling P and SV waves which are incident vertically from the far-field of underlying half-space to the near-field of layered medium. The equivalent earthquake forces are then calculated utilizing so-called fixed-exterior-boundary-method and the free-field responses including displacements and tractions. For the verification of the present study, seismic response analyses are carried out for a multi-layered half-space free-field soil medium and a cylindrical cavity embedded in a homogeneous half-space. Comparisons of the present results with solutions by other approaches indicate that the proposed methodology gives accurate estimates. Finally, an application example of seismic response analysis for a subway station is presented, which demonstrates the applicability of the present study.

• Journal of Aerospace System Engineering
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• v.13 no.3
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• pp.32-39
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• 2019

Sensor pods mounted on the exterior of the aircraft used for tactical missions should have a fatigue life based on the expected load spectrum during operation. For mission equipment such as the sensor pod, the frequency fatigue life prediction method which applies the dynamic vibration environment condition is preferred due to the efficiency of the analysis. In this paper, a fatigue life prediction method in the frequency domain where stress due to static and dynamic loads is synthesized based on the actual flight load spectrum is proposed. After comparison with the existing analysis method, the fatigue life of the proposed analysis method was predicted conservatively. The proposed sensor pods satisfy the requirements of the fatigue life.

• Journal of the Korean housing association
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• v.22 no.5
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• pp.37-46
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• 2011

Residential space has come to maintain a degree of specialization dependent upon the division of space according to function, while roles and functions have either expanded or ceased to exist corresponding to shifts in social values. However, various human behaviors connected to lifestyle habits and values are in fact becoming obsolete. This research will examine the mental, social, and functional aspects of the relationship between residential work spaces in modern homes and the sarangche as well as the communal space of daily and social life of the Chosun Dynasty to enhance the value and function of traditional residential space. As the boundary between family and work blurs with the home office environment of today, we are experiencing a deterioration of health and seeing problems in securing family domain as well as the prolonging of overwork. While the function of the traditional sarangchae encompassed a wider variety of activities than today's homes, the sarangchae achieved an efficient use of space divisions between rooms according to the particular purpose and situation. Accordingly, a reinterpretation of modern residential work space is needed through its connection to the sarangchae with consideration to the philosophy and values of the life of the noble class and the habits of our traditional lifestyle that have previously taken place within the sarangchae in an exterior space.

• International Journal of Naval Architecture and Ocean Engineering
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• v.2 no.3
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• pp.146-154
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• 2010

In the present study, the wave excitation forces acting on an array of porous circular cylinders are examined based on diffraction problems. To calculate the wave forces, the fluid domain is divided into three regions i.e. a single exterior region, N interior regions and N beneath regions, and the diffraction in each fluid region is expressed by an eigenfunction expansion method with using 3-dimension liner potential theory (Williams and Li, 2000). Especially, the present method is extended to the case of an array of truncated porous circular cylinders to calculate the heave forces as well as surge and sway forces. To verify this method, the numerical results obtained by eigenfunction are compared with these results obtained by higher order boundary element method (Choi et al., 2000). The numerical results obtained by this study are in good agreement with those results. By changing the numbers of porous circular cylinders, the angle of incident wave and the porosity rate of circular cylinders, the wave excitation forces such as surge, sway and heave on an array of truncated porous circular cylinders are investigated.

• Ocean Systems Engineering
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• v.1 no.4
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• pp.337-353
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• 2011

In the present study, an offshore platform having large partial porous cylindrical members, which are composed of permeable and impermeable cylinders, is suggested. In order to calculate the wave force on large partial porous cylindrical members, the fluid domain is divided into three regions: a single exterior region, N inner regions and N beneath regions, and the scattering wave in each fluid region is expressed by an Eigen-function expansion method. Applying Darcy's law to the porous boundary condition, the effect of porosity is simplified. Wave excitation forces and wave run up on the structures are presented for various wave conditions. For the idealized three-dimensional platform having large partial porous cylindrical members, the dynamic response evaluations of the platform due to wave forces are carried out through the modal analysis. In order to examine the effects of soil-structure interaction, the substructure method is also applied. The displacement and bending stress at the selective nodal points of the structure are computed using various input parameters, such as the shear-wave velocity of soil, the wave height and the wave period. Applying the Monte Carlo Simulation (MCS) method, the reliability evaluations at critical structure members, which contained uncertainties caused by dynamic forces and structural properties, are examined by the reliability index with the results obtained from MCS.