• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제9권1호
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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.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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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.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1999년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall
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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.

• 건축역사연구
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• 제3권2호
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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.

• 한국학교수학회논문집
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• 제16권2호
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• pp.363-381
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• 2013

수학학습양식의 4가지 구성요인은 인지적 학습양식에서 정보인식 유형과 정보처리 유형이고 정의적 학습양식에서 수학학습에 대한 태도와 수학학습 환경에 대한 태도이다. 각 요인은 대립하는 두 개의 양식으로 구분되며 정보인식 유형은 시각적 양식과 언어적 양식으로, 정보처리 유형은 전체적 양식과 분석적 양식으로, 수학학습에 대한 태도는 권위목표형과 실용오락형으로, 수학학습 환경에 대한 태도는 내부지향형과 외부지향형으로 나눌 수 있다. 총 8가지의 수학학습양식의 조합에 의하여 16가지 수학학습유형으로 분류된다. 본 연구는 중학교 3학년 학생들을 대상으로 수학학습양식과 수학학습유형에 대한 선호도를 분석하여 학습자의 개인차를 인식하고 효과적인 수업전략을 모색하는데 시사점을 제공하고자 한다.

• 한국전산구조공학회논문집
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• 제13권2호
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• pp.231-244
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• 2000

본 연구에서는 지하철구조물, 터널구조물 및 제방 등과 같은 2차원 지반-구조계의 지진응답해석을 위한 주파수영역 동적해석법을 제시하였다. 제시한 방법에서는 구조물과 구조물 주변 근역지반은 유한요소를 이용하고 원역지반은 주파수종속 동적무한요소를 이용하여 모형화하였다. 지진입력은 입력지진파를 수직으로 입사하는 P-파와 SV-파로 가정하여 자유장응답을 구하였으며 외부고정경계법을 적용하여 등가지진하중을 산정하였다. 본 연구기법의 검증을 위하여, 층상 자유장지반과 균질 반무한지반에 매입된 원동형 공동에 대하여 지진응답을 수행하였다. 이들을 다른 기법에 의한 해와 비교한 결과, 본 연구의 기법이 매우 정확함을 알 수 있었다. 마지막으로 지하철 역사의 지진응답해석 예제를 제시하여 본 연구의 적용성을 보였다.

• 항공우주시스템공학회지
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• 제13권3호
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• pp.32-39
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• 2019

항공기 외부에 장착되어 전술임무에 사용되는 센서 포드는 운용기간 동안 예상되는 하중 스펙트럼에 대한 피로수명이 확보되어야 한다. 센서 포드와 같은 임무장비는 해석의 효율성을 고려하여 동적 진동 환경조건을 적용한 주파수 영역의 피로수명 예측방법이 선호되어 왔다. 본 논문에서는 실제 비행체 하중 스펙트럼을 고려하여 정적 및 동적 하중에 의한 응력을 합성한 주파수 영역에서의 피로수명 예측방법을 제안하였다. 기존 해석방법과 비교한 결과 제안된 해석방법은 피로수명이 보수적으로 예측되었다. 그리고 제안된 방법으로 해석한 결과 설계된 센서 포드는 피로수명 요구조건을 만족하였다.

• 한국주거학회논문집
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• 제22권5호
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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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• 제2권3호
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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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• 제1권4호
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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.