• 농촌계획
• /
• 제4권2호
• /
• pp.128-137
• /
• 1998

The objective of this study is to approach on the spatial boundary of rural development protect by areal classification technique with spatial reference to searching of areal homogeneities in two hierachial administrative units, Ri Eup/Myun. In this study, a criterion for judging areal homogeneities is the degree of agriculture and urbanizing. Variables selected by these two criteria are analysed with the method of fator analysis. The results of areal analysis are as follows: first, generally, the importance of agricultural factors in areal analysis is getting less. Second, areal classification by Myun, Ri in Ansong City is revealed variously because of urban factors. Urban factors make areal heterogeneities become greater, Therefore urban factors are important when analyzing areal characteristics. Third, lately, in areas near by Chung- cheong Do and areas with bad road's condition, areal heterogeneities have been also getting greater. The results of analysis about areal characteristics of Myun and Ri are different from each other. In addition, urban factors are more influential on the areal characteristics than agricultural factors. Therefore, the establishment of rural development project for inindle spatial boundary between Myun unit and Ri unit is needed.

• Earthquakes and Structures
• /
• 제17권6호
• /
• pp.557-566
• /
• 2019

The evaluation of the seismic hazard for a given site is to estimate the seismic ground motion at the surface. This is the result of the combination of the action of the seismic source, which generates seismic waves, the propagation of these waves between the source and the site, and site local conditions. The aim of this work is to evaluate the sensitivity of dynamic response of extended structures to spatial variable ground motions (SVGM). All factors of spatial variability of ground motion are considered, especially local site effect. In this paper, a method is presented to simulate spatially varying earthquake ground motions. The scheme for generating spatially varying ground motions is established for spatial locations on the ground surface with varying site conditions. In this proposed method, two steps are necessary. Firstly, the base rock motions are assumed to have the same intensity and are modelled with a filtered Tajimi-Kanai power spectral density function. An empirical coherency loss model is used to define spatial variable seismic ground motions at the base rock. In the second step, power spectral density function of ground motion on surface is derived by considering site amplification effect based on the one dimensional seismic wave propagation theory. Several dynamics analysis of a curved viaduct to various cases of spatially varying seismic ground motions are performed. For comparison, responses to uniform ground motion, to spatial ground motions without considering local site effect, to spatial ground motions with considering coherency loss, phase delay and local site effects are also calculated. The results showed that the generated seismic signals are strongly conditioned by the local site effect. In the same sense, the dynamic response of the viaduct is very sensitive of the variation of local geological conditions of the site. The effect of neglecting local site effect in dynamic analysis gives rise to a significant underestimation of the seismic demand of the structure.

• 한국공간구조학회논문집
• /
• 제5권2호
• /
• pp.81-87
• /
• 2005

The Space structures may have large freedom in scale and form. And especially Hybrid structures are received much attention from the view points of their light weight and aesthetics. Hybrid systems are stable structures which are reticulated spatial structures composed of compressive straight members, struts and cables and Membranes. In this paper, The Hybrid Unit System are suggested using the Membrane and Cable elements based on the Tensegrity Unit system. Also, The Hybrid System of double-layered single curvature is presented. We analyze the force density method allowing form-finding for Tensegrity systems. And We analyze the shape analysis by the LARSH which is the program for nonlinear analysis.

• 한국컴퓨터정보학회논문지
• /
• 제11권1호
• /
• pp.27-34
• /
• 2006

최근 공간 정보들을 효과적으로 이용할 수 있는 기술에 대한 연구가 활발하게 이루어지고 있다. 효율적인 지식 탐사를 위해 다양한 기존의 데이터 마이닝 방법들이 확장되어 공간 데이터 마이닝에 사용되고 있다. 그러나 기존의 공간 연관 규칙 탐사 시스템들은 프레디킷 간의 연산을 통해 규칙을 발견함에 따라 질의 결과에 다양한 비공간 속성들을 반영하지 못하는 문제점을 가지고 있다. 본 논문에서는 이러한 문제점을 해결하기 위해 공간 데이터베이스에서 사용되는 질의를 확장하고, 위상정보에 따른 데이터를 구성한 후 비공간 객체 속성간의 연관 규칙을 발견하는 시스템을 제안한다. 특히 지리 정보 시스템에 적용 가능한 모델을 구현하였다. 이렇게 구현된 시스템은 사용 중인 공간 데이터베이스를 확장하므로 이식성이 뛰어나고, 공간 속성뿐만 아니라 다양한 비공간 속성을 고려함으로써 좀 더 실생활에 유용한 공간 연관 규칙을 발견할 수 있다.

• Spatial Information Research
• /
• 제17권3호
• /
• pp.277-285
• /
• 2009

효율적으로 데이터를 관리, 분석, 유지하기 위해서는 각 시스템의 목적에 맞는 데이터 모델이 필요하다. 데이터 모델에 따라 해당하는 활용 시스템의 활용 범위가 결정되며, 각각의 활용 시스템에 맞는 데이터 모델이 개발되고 있는 상황이다. GIS 분야에서도 각 GIS 응용시스템에 맞는 다양한 공간정보 데이터 모델들이 개발 되었으며, 제공하고자 하는 서비스에 따라 공간정보 데이터 모델이 만들어지고 있다. 어플리케이션의 효율적인 활용을 위해서는 공간정보 데이터의 정확성과 최신성등이 중요하지만 특히 공간정보 데이터 구조를 만드는 데이터 모델링이 중요하다. 그러므로 본 연구는 1)국내외 공간정보 데이터 모델의 공간정보를 표현하는데 있어 기하학적 모델, 위상학적 모델과 3차원 공간정보 가시화 방법 등의 항목별로 비교하고 2)각각의 데이터 구조를 분석하여 데이터 모델의 특징을 비교한다. 마지막으로 3)공간정보 데이터 모델을 선정하여 정량적인 분석을 통해 데이터 구조에 따른 특징을 분석한다.

• Structural Engineering and Mechanics
• /
• 제73권6호
• /
• pp.651-666
• /
• 2020

In this study, the spatial variation mechanisms of large far-field earthquakes at engineering scales are first investigated with data from the 2008 Ms 8.0 Wenchuan earthquake. And a novel 'coherency cut-off frequency' is proposed to distinguish the spatial variations in ground motions in the low-frequency and high-frequency ranges. Then, a practical piecewise coherency model is developed to estimate and characterize the spatial variation in earthquake ground motions, including the effects of source-to-site distances, site conditions and neighboring topography on these variations. Four particular earthquake records from dense seismograph arrays are used to investigate values of the coherency cut-off frequency for different source-to-site distances. On the basis of this analysis, the model is established to simulate the spatial variations, whose parameters are suitable for both near- and far-field earthquake conditions. Simulations are conducted to validate the proposed model and method. The results show that compared to the existing models, the proposed model provides an effective method for simulating the spatial correlations of ground motions at local sites with known source-to-site distances.

• ETRI Journal
• /
• 제43권5호
• /
• pp.941-949
• /
• 2021

In this study, a spatial spectrum method is proposed to cope with the pilot spoofing attack (PSA) problem by exploiting the of uplink-downlink channel reciprocity in time-division-duplex multiple-input multiple-output systems. First, the spoofing attack in the uplink stage is detected by a threshold derived from the predefined false alarm based on the estimated spatial spectrum. When the PSA occurs, the transmitter (That is Alice) can detect either one or two spatial spectrum peaks. Then, the legitimate user (That is Bob) and Eve are recognized in the downlink stage via the channel reciprocity property based on the difference between the spatial spectra if PSA occurs. This way, the presence of Eve and the direction of arrival of Eve and Bob can be identified at the transmitter end. Because noise is suppressed by a spatial spectrum, the detection performance is reliable even for low signal-noise ratios and a short training length. Consequently, Bob can use beamforming to transmit secure information during the data transmission stage. Theoretical analysis and numerical simulations are performed to evaluate the performance of the proposed scheme compared with conventional methods.

• 연구논문집
• /
• 통권34호
• /
• pp.101-112
• /
• 2004

In order to analyze the motion errors of the aerostatic stage, it is necessary to consider the influence of the moment variation occurredinside the pads. In this paper, a motion error anaysis method utilizing the transfer functions on the reaction force and moment is proposed, and general characteristics of the transfer functions are discussed. Calculated motion errors by the proposed method show good agreement with the ones calculated by Multi Pad Method, which is considered the entire table as an analysis object. Also, by the introduction of the transfer function of motion errors, which represent the relationship between the spatial frequency components of the rail form error and motion errors, motional characteristics of the porous aerostatic stage can be generalized. In detail, the influence of the spatial frequencies is analyzed quantatively, and the patterns of the insensitive frequencies which almost do not affect the linear motion error or angular motion error according to the rail length ratio and the number of the pad are verified. The relationship between the moment variation occurred inside the pads and the motion errors is also verified together.

• 한국콘텐츠학회논문지
• /
• 제12권2호
• /
• pp.461-471
• /
• 2012

본 논문의 목적은 공간적탐색기법을 이용한 부산 주택시장 다이나믹스 분석으로써 MATLAB toolbox M-file을 이용하였다. 본 연구에서 사용된 자료는 2006년부터 2009년 2분기까지 공개된 부산지역 아파트 실거래가 64,530개 자료를 기준으로 법정동을 분류하여 각 평균값을 분석에 이용하였다. 주택시장분석에 많이 이용되는 헤도닉가격 모형은 도시주택경제 분야에서 주택시장 다이나믹스를 설명하는데 강력한 분석기법의 하나이다. 그럼에도 불구하고 전통적인 헤도닉가격 모형은 공간적자기상관의 영향력을 반영하지 않는 단점이 있다. 따라서 본 논문에서는 공간자기상관 관계를 반영한 다양한 공간계량모형, 예를 들어, 공간자기회귀모형(SAR), 공간오차모형(SEM), 일반공간모형(SAC) 등을 보통최소자승법을 이용한 전통적 헤도닉가격 모형과 비교하고자 한다. 이를 위해 결정계수($R^2$), 분산(${\sigma}^2$), 우도함수(Likelihood)의 값 등의 지표들을 이용하였다. 분석결과 공간자기상관을 고려한 공간계량모형이 전통적 헤도닉모형에 비해 높은 설명력을 보여주고 있다. 공간계량모형에서는 공간오차모형(SEM)과 일반공간모형(SAC)이 공간자기회귀모형(SAR) 보다 우수한 설명력을 보이고 있다.

• 대한원격탐사학회지
• /
• 제28권1호
• /
• pp.39-54
• /
• 2012

본 연구의 목적은 KOMPSAT-2 위성영상에 가장 일반적으로 적용 가능한 영상융합기법을 제시하는 것이다. 가장 널리 사용되는 영상융합기법인 HPF, modified IHS, pan-sharpened, wavelet을 지역적, 계절적 특성이 서로 다른 4장의 KOMPSAT-2 위성영상에 적용하였고, 각각의 융합결과를 공간적, 분광적으로 비교분석하였다. 영상융합기법의 품질평가는 시각적 분석과 정량적 분석을 병행하여 수행하였으며, 정량적 분석에는 spatial ERGAS, spectral ERGAS, SAM, Q4가 사용되었다. 종합적인 분석결과를 고려할 때, pan-sharpened가 색상정보와 공간정보의 균형적인 보존 측면에서 다른 융합기법들에 비해, 상대적으로 우수한 결과를 나타냈다. modified-IHS의 경우, 공간정보는 잘 보존하였지만 다소 큰 색상 왜곡이 발생되었고, HPF와 wavelet은 색상 왜곡은 적었지만, 공간정보의 왜곡이 발생하였다.