• 한국공간구조학회논문집
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• 제22권2호
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• pp.57-64
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• 2022

In this paper, the physical model and governing equations of a shallow arch with a moving boundary were studied. A model with a moving boundary can be easily found in a long span retractable roof, and it corresponds to a problem of a non-cylindrical domain in which the boundary moves with time. In particular, a motion equation of a shallow arch having a moving boundary is expressed in the form of an integral-differential equation. This is expressed by the time-varying integration interval of the integral coefficient term in the arch equation with an un-movable boundary. Also, the change in internal force due to the moving boundary is also considered. Therefore, in this study, the governing equation was derived by transforming the equation of the non-cylindrical domain into the cylindrical domain to solve this problem. A governing equation for vertical vibration was derived from the transformed equation, where a sinusoidal function was used as the orthonormal basis. Terms that consider the effect of the moving boundary over time in the original equation were added in the equation of the transformed cylindrical problem. In addition, a solution was obtained using a numerical analysis technique in a symmetric mode arch system, and the result effectively reflected the effect of the moving boundary.

• 한국측량학회지
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• 제17권2호
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• pp.177-187
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• 1999

현재까지 GSIS를 이용하는 많은 응용분야에서 각종 공간자료의 추출 및 분석을 위해 벡터형 공간중첩(spatial overay)이나 격자형 공간연산(spatial algebra)기능이 주로 사용되었다. 하지만 이런 방법에 내재하고 있는 개념은 전통적인 보통집합이론에 근거하고 있기 때문에 많은 종류의 공간자료들이 구간설정에 있어서 예리한 경계로 분할되는 것으로 다루어지고 있다. 이것은 현실 세계에 존재하는 실제 자료들의 공간분포패턴과 일치하지 않는다. 즉, 공간상에 일정영역이나 실체들이 오직 한가지 속성으로 한정되는(one-entity-one-value)오류를 그대로 포함하고 있다. 본 연구는 이러한 보통집합의 개념하에서 공간자료를 다루어 왔던 종래의 방식을 개선하기 위해서 공간자료가 지니는 모호함 내지 경계의 애매성을 잘 표현할 수 있는 퍼지집합의 개념을 두 가지 방법을 통해 공간중첩과정에 도입하였다. 첫 번째 방법은 공간적으로 연속성을 갖는 자료에 대해서 퍼지부분집합에 의한 퍼지구간분할법이며, 두 번째 방법은 범주형 자료에 대해서 적용한 퍼지경계집합법이다. 사례연구로서 신시가지 개발입지선정을 위한 적지분석을 수행을 함으로서 기존의 부울분석방법과 퍼지 공간 중첩법의 결과를 비교하였으며 그 결과, 퍼지공간중첩법에 의한 적합도면이 신시가지 개발입지에 대한 보다 타당성 있는 정보를 제공하며, 더불어 정보표현측면에서도 더욱 적절한 형태임을 알 수 있었다.

• 대한건축학회논문집:계획계
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• 제35권5호
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• pp.3-10
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• 2019

This study is purposed to analyze of House Vision exhibition and projects in Japan. The contemporary residence has been planned and designed with fixed territory and boundary of rooms. According to the symposium of House Vision, the spatial boundary can be studied in the aspect of territory that molds the experience of residents. So, this study reviews Aldo van Eyck's concept of 'in-between'. Through the analysis, House Vision exhibition is revealed that the housing models present architectural characteristics of middleware and third place. The cognition of internal and external boundary stems from movements and activities of residents. That is the dwelling and residential space determined by users and residents. In this regard, 'in-between' of House Vision has structures(multilayer) causing various relationships to be perceived, so as to connect with the dwelling and activities of residents. As a result, it has relational meanings of sharing, as well as makes possible other community life to be done. According to the projects of House Vision, the units and cores have created the new connections and relationships between privacy and publicity. In conclusion, this research shows a new direction of the spatial strategies on House Vision exhibition in Japan.

• Spatial Information Research
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• 제18권5호
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• pp.27-36
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• 2010

본 연구에서는 툰드라-타이가 경계영역의 변화를 확인하기 위해 식생의 분포 변화를 관측하였다. 툰드라-타이가 경계영역은 인간 활동 혹은 기후 변화에 따른 신호로 나타나는 식생패턴의 이동을 관측하기 위해 사용된다. 극지의 툰드라-타이가 경계영역은 조금의 변화에 대해서도 두드러진 반응을 관찰 할 수 있으므로 다른 곳에 비해 기후변화에 대한 반응과 확인이 명확하다. 연구 자료로서 2000년에서 2009년까지 총 10년간 매년 8월을 Terra위성 MODIS(MODerate resolution Imaging Spectroradiometer) 센서로부터 취득한 LAI(Leaf Area Index) 8-Day 자료를 사용하였고, 보조 자료로서 기후지도와 GLC 2000(Global Land Cover 2000)토지피복 지도를 사용하였다. 본 연구에서는 엽면적 지수의 10년치 장기간 자료를 이용하여 시 공간 분석과 식생의 밀도가 저조한 지역을 중심으로 위도대 별, 토지피복 별분석을 시행하였다. 연구대상 지역에 대하여 엽면적 지수의 기준값을 바탕으로 한 분석에서 2000년에서 2009년까지 LAI의 변화를 확인하였다. 툰드라 기후에서 식생의 감소가 일어난 면적($22,372km^2$) 보다 식생의 성장을 보인 면적은 $730,325km^2$ 로서 식생의 발달을 확인할 수 있었다. 또한 위도대 별 면적 분석을 통해 위도 $62^{\circ}$ N의 주위와 위도 $64^{\circ}$ N~$66^{\circ}$ N을 중심으로 면적 증가가 나타났으며, 툰드라-타이가 경계영역의 식생은 2000년부터 2009년까지 전반적인 증가 추세가 나타났다. 전체적으로 식생 감소가 일어나는 면적 변화는 다소 적은 것에 비해 식생의 성장과 발달이 일어나는 곳의 면적은 크게 증가하는 것을 확인하였다.

• Spatial Information Research
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• 제15권1호
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• pp.53-65
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• 2007

지상라이다는 고정도의 3차원 영상을 제공하고 레이저빔을 현장이나 대상물에 발사하여 짧은 시간에 수백만점의 3차원좌표를 기록할 수 있는 최신 측량장비로서 다양한 응용분야에서 두각을 나타내고 있다 본 연구에서는 지상라이다를 이용한 아파트 건축물의 3차원 경계 추출을 다루었다. 실험측량결과 지상라이다로 아파트건축물의 3차원 경계를 신속하게 추출할 수 있었지만 지상기반시스템이므로 건축물 지붕 그리고 나무, 전주 때문에 건축물 저층부에서는 이것이 쉽지 않았다. 향후 토탈스테이션, 지상라이다, 항공라이다와 항공사진측량과의 결합을 통해 효율적인 3차원공간정보 획득이 가능할 것으로 기대된다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집B
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• pp.585-590
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• 2000

The hydrodynamic instability of the three-dimensional boundary layer on a rotating disk introduces a periodic modulation of the mean flow in the form of stationary cross flow vortices. Detailed numerical values of the growth rates, neutral curves and other characteristics of the two instabilities have been calculated over a wide range of parameters. Presented are the neutral stability results concerning the two instability modes by solving new linear stability equations reformulated not only by considering whole convective terms but by correcting some errors in the previous stability equations. The present stability results are agree with the previously known ones within reasonable limit. The flow is found to be always stable for a disturbance whose dimensionless wave number at Re=1200 is greater than 0.75. Also, the spatial amplification contours have been calculated for the moving disturbance wave, whose azimuth angle is between ${\varepsilon}=15^{\circ}$ and $12.5^{\circ}$.

• Wind and Structures
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• 제7권6호
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• pp.373-392
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• 2004

This paper presents a methodology for spatial extrapolation of wind-induced pressure time series from a corner bay to roof locations on a low building away from the corner through the application of proper orthogonal decomposition (POD). The approach is based on the concept that pressure time series in the far field can be approximated as a linear combination of a series of modes and principal coordinates, where the modes are extracted from the full roof pressure field of an aerodynamically similar building and the principal coordinates are calculated from data at the leading corner bay only. The reliability of the extrapolation for uplift time series in nine bays for a cornering wind direction was examined. It is shown that POD can extrapolate reasonably accurately to bays near the leading corner, given the first three modes, but the extrapolation degrades further from the corner bay as the spatial correlations decrease.

• Journal of applied mathematics & informatics
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• 제32권5_6호
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• pp.585-598
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• 2014

In this paper we consider the nonlinear parabolic problems with mixed boundary condition. Under comparatively mild conditions of the coefficients related to the problem, we construct the discontinuous Galerkin approximation of the solution to the nonlinear parabolic problem. We discretize spatial variables and construct the finite element spaces consisting of discontinuous piecewise polynomials of which the semidiscrete approximations are composed. We present the proof of the convergence of the semidiscrete approximations in $L^{\infty}(H^1)$ and $L^{\infty}(L^2)$ normed spaces.

• 한국공간구조학회논문집
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• 제1권2호
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• pp.101-110
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• 2001

A large floating structure is attracting great attention in recent years from the view of ocean space utilization. Its huge scale in the horizontal directions compared with the wavelength and relatively shallow depth make this type of floating structure flexible and its wave-induced motion be characterized by the elastic deformation. In this paper, a boundary integral equation method is proposed to predict the wave-induced dynamic response mat-like floating offshore structure. The structure is modeled as an elastic plate and its elastic deformation is expressed as a superposition of free-vibration modes in air. This makes it straightforward to expand the well-established boundary integral technique for rigid floating bodies to include the hydroelastic effects. In order to validate the theoretical analysis, we compare with the experimental result of reduced model test. Satisfactory agreement is found between theory and experiment.

• 한국공간구조학회논문집
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• 제2권3호
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• pp.71-79
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• 2002

The purpose of this paper is to study the buckling characteristics of elliptical latticed domes under conservative loading conditions. The latticed domes are usually designed in geometrically spherical shape. For this type of latticed domes, many researchers have researched and even the simplified estimation codes for the buckling load level have been available. However, geometrically elliptical latticed domes have been often constructed, and show different buckling characteristics following with geometrical parameters as rise-to-span ratio and so on. Therefore, it is necessary to investigate the general tendency of buckling characteristics of the elliptical latticed domes. In this paper, to find out some buckling characteristics of elliptical latticed domes, height, boundary configuration and gap are used as the shape coefficients. For each model with different parameters, the eigen values and the buckling loads are evaluated.