• 대한토목학회논문집
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• 제29권3B호
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• pp.269-279
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• 2009

대유역에서 계획홍수량 추정은 ARF, 강우 시공간분포 및 강우-유출 모형의 매개변수 등에서 많은 불확실성이 발생한다. 과거 동시 강우사상을 이용한 계획홍수량의 추정은 이들 불확실성을 개선할 수 있다. 본 연구는 과거 동시 강우사상과 저류 함수모형을 이용하여 대유역의 홍수량을 추정하는 방법을 제시하였다. 과거 동시 강우사상의 시공간분포를 이용하여 계획 강우량과 강우의 시공간분포를 산정하였고 비선형 강우-유출 반응을 재현할 수 있는 저류함수모형을 이용하여 홍수량을 추정하였다. 추정된 계획홍수량은 실측홍수량에 의한 빈도분석 결과와 비교하여 본 연구에서 제시한 홍수량 추정기법의 적용성을 평가하였다. 본 연구의 결과는 실측홍수량의 빈도해석과 비슷한 결과를 얻었으며 이는 대유역의 홍수량 추정에서 본 연구의 홍수량 추정과정을 충분히 이용할 수 있음을 보여준다.

• Spatial Information Research
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• 제4권1호
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• pp.55-74
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• 1996

본 연구는 대도시지역의 공간구조를 결정하는 가장 중요한 도시기능인 상업업무기능이 집적되는 요인을 규명하고자 하는데 그 목적이 있다. 상업업무기능이 집적되는 데 작용하는 요인들은 매우 다양하다. 본 연구는 지리정보시스템(GIS)를 활용함으로써 그동안의 선행연구들이 기구축된 자료의 부족으로 인해 부분적으로만 고려하였던 요인들을 분석변수로 포함시켜 상업업무기능의 분포특성을 파악하고자 하였다. 본 연구는 행정동을 기초로 설정한 서울시 409개 분석단위지역을 대상으로 1981년 및 1991년의 상업업무기능 집적수준을 입지 및 접근성, 지형, 인구분포특성, 도시정책 등과 관련시켜 상호관계를 규명하였다. 연구결과 그동안 보편적으로 받아들여졌던 여러 가지 요인들이 상당한 수준에서 상업기능집적에 영향을 미치는 것으로 밝혀졌다. 분석과정에서 활용한 지리정보시스템은 도시공간계획에서 매우 유용한 수단을 제공함으로써 향후에 더욱 심도있는 연구가 진행될 것으로 전망된다.

• 천문학논총
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• 제7권1호
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• pp.231-253
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• 1992

A model for the distribution of stars in the disk and the spheroid of our Galaxy is reexamined from an edge-on view of the Galaxy obtained by selecting infrared sources from the IRAS Point Source Catalog. The sources are counted as a function of galactic latitude. longitude and $12{\mu}m$ apparent magnitude. The source counts are reasonably separated into the disk component and the spheroid component contributions and each of the contributions is further interpreted as a convolution of a spatial density distribution and a luminosity function based on the least-square fit method. The spatial density of the disk component has an exponential radial scale length of $h_R{\sim}2.6\;kpc$ and the vertical distribution follows a canonical $sech^2$ law with a scale height $h_z{\sim}240\;pc$. The distribution of the spheroid component can be represented by an oblate spheriod with an axis ratio $k{\sim}0.61$ and a de Vaucouleurs' $r^{1/4}$ law with an effective radius of $R_e{\sim}120\;pc$. The steep density gradient of the spheroid component is consistent with that of late M giants in the central bulge. The luminosity functions of the disk and the spheroid component stars resemble respectively those of the K luminosity function of disk M giants (Garwood and Jones 1986) and the bolometric luminosity function of M giants in bulge fields (Frogel et al, 1990).

• Spatial Information Research
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• 제18권1호
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• pp.89-99
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• 2010

기존 축제정보 웹사이트에서 지리 정보가 텍스트 중심으로 제공되어 지리정보의 효율적인 전달이 이루어지지 않는다는 문제점이 있었다. 이를 극복하기 위해 지도를 기반으로 축제관련 최신기사를 위치기반으로 매쉬업하여 표출하는 축제정보 사이트를 구현하였다. 축제관련 신문 기사 제공방법으로 GeoRSS 기능을 활용함으로써 신문기사를 통해 최근 축제정보를 지도를 기반으로 한눈에 파악할 수 있도록 하였다. 축제정보를 지도기반으로 재조직함으로써 정보전달이 효율적으로 이루어지는 것을 확인할 수 있었고, 지도기반 최신정보 제공의 가능성과 GeoRSS 기술의 활용가능성을 확대하였다.

• 한국공간구조학회논문집
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• 제18권1호
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• pp.77-84
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• 2018

The identification of damping ratios in buildings is a well-known problem and appears to be of important and crucial interest in the safety and serviceability design. When compared to an estimation of the stiffness, i.e. natural frequency, and mass, the damping ratio is the most difficult quantity to determine. Many previous studies have examined the characteristics of damping ratios from ambient vibration, but the measurement time is roughly within 2 hours. In this paper, characteristics of damping ratios and natural frequencies of 4 story RC building were investigated using long-term ambient vibration. Free vibrations were obtained using random decrement technique, and damping ratios were evaluated by the envelop function, continuous wavelet transform, and logarithmic decrement. It was found that although the natural frequencies show little variations with time, the damping ratios show some variations with time and the largest variations found in the damping ratios obtained from the continuous wavelet transform. The damping ratios from the envelop function showed the smallest mean and standard deviation. And the probability distribution of damping ratios seems to follow the logarithmic normal distribution.

• 한국공간구조학회논문집
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• 제19권2호
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• pp.101-108
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• 2019

In this paper, the characteristic of intrinsic mode function(IMF) and its orthogonalization of ensemble empirical mode decomposition(EEMD), which is often used in the analysis of the non-linear or non-stationary signal, has been studied. In the decomposition process, the orthogonal IMF of EEMD was obtained by applying the Gram-Schmidt(G-S) orthogonalization method, and was compared with the IMF of orthogonal EMD(OEMD). Two signals for comparison analysis are adopted as the analytical test function and El Centro seismic wave. These target signals were compared by calculating the index of orthogonality(IO) and the spectral energy of the IMF. As a result of the analysis, an IMF with a high IO was obtained by GSO method, and the orthogonal EEMD using white noise was decomposed into orthogonal IMF with energy closer to the original signal than conventional OEMD.

• Journal of Information Processing Systems
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• 제17권3호
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• pp.645-657
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• 2021

Along with the rapid development of the economy, the urban scale has extended rapidly, leading to the formation of different types of urban function districts (UFDs), such as central business, residential and industrial districts. Recognizing the spatial distributions of these districts is of great significance to manage the evolving role of urban planning and further help in developing reliable urban planning programs. In this paper, we propose an automatic UFD division method based on big data analysis of point of interest (POI) data. Considering that the distribution of POI data is unbalanced in a geographic space, a dichotomy-based data retrieval method was used to improve the efficiency of the data crawling process. Further, a POI spatial feature analysis method based on the mean shift algorithm is proposed, where data points with similar attributive characteristics are clustered to form the function districts. The proposed method was thoroughly tested in an actual urban case scenario and the results show its superior performance. Further, the suitability of fit to practical situations reaches 88.4%, demonstrating a reasonable UFD division result.

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

• Nuclear Engineering and Technology
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• 제54권6호
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• pp.2204-2212
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• 2022

Recently, the demand for alpha imaging detectors for quantifying the distributions of alpha particles has increased in various fields. This study aims to reconstruct a high-resolution image from an alpha imaging detector by applying a super-spatial resolution method combined with the maximum-likelihood expectation maximization (MLEM) algorithm. To perform the super-spatial resolution method, several images are acquired while slightly moving the detector to predefined positions. Then, a forward model for imaging is established by the system matrix containing the mechanical shifts, subsampling, and measured point-spread function of the imaging system. Using the measured images and system matrix, the MLEM algorithm is implemented, which converges towards a high-resolution image. We evaluated the performance of the proposed method through the Monte Carlo simulations and phantom experiments. The results showed that the super-spatial resolution method was successfully applied to the alpha imaging detector. The spatial resolution of the resultant image was improved by approximately 12% using four images. Overall, the study's outcomes demonstrate the feasibility of the super-spatial resolution method for the alpha imaging detector. Possible applications of the proposed method include high-resolution imaging for alpha particles of in vitro sliced tissue and pre-clinical biologic assessments for targeted alpha therapy.

• 의료ㆍ복지 건축 : 한국의료복지건축학회 논문집
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• 제28권3호
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• pp.17-26
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• 2022

Purpose: The purpose of this study is to classify space types according to the operating system of health examination centers and compare and analyze their sizes. Methods: Seven examination centers under the K Medical Research Institute with the same operating system and similar examination types and functional spaces are the subject of the investigation. Research is conducted through field investigation, user surveys, and drawing analysis. Results: The operating method of the health examination center can be largely divided into the function dispersed type and the function central type. The function dispersed type was planned as a vertical type, and the function central type was planned as a horizontal type. In the case of the function dispersed type, since the examinees move vertically to use the endoscope center and special examination center, the efficiency of the vertical movement must be considered when planning the function dispersed type of facility. The function dispersed type plans to increase work and manpower efficiency by arranging the areas used at the start and end of the examination. Because the function central type horizontally arranges related functions by area, it should be planned in a structure that makes it easy for examinees to find their way. Implications: Through this study, it is judged that it is possible to suggest architectural planning considerations that vary depending on the operation system of the examination center.