• The Journal of the Korea Contents Association
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• v.15 no.10
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• pp.150-159
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• 2015

This study attempted to test the scale effect of MAUP, particularly focusing on the spatial autocorrelation of sex crime, correlations among neighborhood structural variables, and causal mechanism leading to sex crime. Analysis results of nation-wide Eup-Myon-Dong and Si-Gun-Gu data discovered that the spatial autocorrelation, correlations among independent variables, and determinant coefficient of multiple regression of Si-Gun-Gu level were generally bigger and stronger than those of Eup-Myon-Dong, which appeared to be due to the averaging effect. Regarding the causal effect to sex crime, two interesting results were found: First, the ratio of non-apartment residency lowered sex crime at both levels contrary to the hypothesis. Second, the ratio of food and lodging increased sex crime only at Eup-Myon-Dong level. These suggested that future research need to perform more detailed analyses dividing data into subsets such as urban vs. rural and/or economically advantaged vs. disadvantaged areas.

• Journal of the Korean GEO-environmental Society
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• v.14 no.2
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• pp.13-17
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• 2013

Clogging phenomenon in drainage system is one of the important problems and this phenomenon would be bad effect to structure of tunnel, so it needs a remedy urgently. Recently, scale in drainage pipe is removed by water jet cleaning and other treatment. But these treatments need much cost and regular management. In this study, magnetic device was used to solve this problem and an effect of prohibiting scale in accordance with array of magnetic device was investigated. Analysis method was visual analysis and measuring weight of each pipes. As a result, interior top and out-bottom (CASE II) was the most effective array to prohibit scale. and interior left and right (CASE III), interior top and bottom (CASE I) was effective for prohibiting scale in order.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.11
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• pp.5930-5938
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• 2013

The sigmoid functionally graded mateiral(S-FGM) theory is reformulated using the nonlocal elatictiry of Erigen. The equation of equilibrium of the nonlocal elasticity are derived. This theory has ability to capture the both small scale effects and sigmoid function in terms of the volume fraction of the constituents for material properties through the plate thickness. Navier's method has been used to solve the governing equations for all edges simply supported boundary conditions. Numerical solutions of biaxial buckling of nano-scale plates are presented using this theory to illustrate the effects of nonlocal theory and power law index of sigmoid function on buckling load. The relations between nonlocal and local theories are discussed by numerical results. Further, effects of (i) power law index, (ii) length, (iii) nonlocal parameter, (iv) aspect ratio and (v) mode number on nondimensional biaxial buckling load are studied. To validate the present solutions, the reference solutions are discussed.

• The Journal of the Korea Contents Association
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• v.14 no.3
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• pp.11-21
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• 2014

Multi-scale image segmentation is important in many applications such as image stylization and medical diagnosis. This paper proposes a novel segmentation algorithm based on MSER(maximally stable extremal region) which captures multi-scale structure and is stable and efficient. The algorithm collects MSERs and then partitions the image plane by redrawing MSERs in specific order. To denoise and smooth the region boundaries, hierarchical morphological operations are developed. To illustrate effectiveness of the algorithm's multi-scale structure, effects of various types of LOD control are shown for image stylization. The proposed technique achieves this without time-consuming multi-level Gaussian smoothing. The comparisons of segmentation quality and timing efficiency with mean shift-based Edison system are presented.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.1
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• pp.436-444
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• 2013

This article presents the dynamic response of nano-scale plates using the nonlocal continuum theory and higher-order shear deformation theory. The nonlocal elasticity of Eringen has ability to capture the small scale effects and the higher-order shear deformation theory has ability to capture the quadratic variation of shear strain and consequently shear stress through the plate thickness. The solutions of transient dynamic analysis of nano-scale plate are presented using these theories to illustrate the effect of nonlocal theory on dynamic response of the nano-scale plates. The relations between nonlocal and local theories are discussed by numerical results. Also, the effects of nonlocal parameters, aspect ratio, side-to-thickness ratio, size of nano-scale plate and time step on dynamic response are investigated and discussed. The amplitude and cycle increase when nonlocal parameter increase. In order to validate the present solutions, the reference solutions are used and discussed. The theoretical development as well as numerical solutions presented herein should serve as reference for nonlocal theories as applied to the transient dynamic analysis of nano-scale structures.

• Journal of the Korean Applied Science and Technology
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• v.34 no.4
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• pp.908-914
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• 2017

In this study, we developed a system that automatically removes the scale in the piping by using electrolysis principle in order to solve the cooling performance of the refrigeration and air conditioning system by acting as heat resistance in the heat transfer process by forming the scale in the heat exchanger for refrigeration air conditioning. We want to check the performance through experiments. Therefore, by circulating the treated water using the principle of electrolysis without stopping the system, Ca, Mg and $SiO_2$ are precipitated in the form of solids and discharged to the outside of the pipe system, thereby preventing scale formation in the pipe and removing the scale. Thereby maintaining the heat transfer performance of the pipe. As a result of the experiment, the heat transfer rate of the scaled pipe was 86.66% when the heat transfer rate of the new pipe was 100, and the heat transfer rate was recovered to 90.5% when the scaled pipe was operated for 1 month. The heat transfer rate recovered to 97.86% when driving for two months and to 98.72% for three months. It was confirmed that the scaling effect of the scale formed in the piping was understood in a relatively short experiment period, and the heat transfer performance was also influenced.

• Proceedings of the IEEK Conference
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• 2001.09a
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• pp.59-63
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• 2001

기존 스케일러빌러티(scalability) 동영상 부호화 알고리듬 의 문제점을 개선하기 위하여 본 논문에서는 다중 레퍼런스 프레임 방법을 기저 계층(base layer)과 확장 계층(enhancement layer)의 움직임 보상시 사용하여, 부호화 효율 및 드리프트 현상을 현저히 감소시키는 효과를 가져온다. 전산 모의 실험을 통하여 제안 알고리듬은 기존의 H.263+ 알고리듬에 비해 스케일러빌러티 모드를 작동하였을 때와 작동하지 않았을 경우 모두에 대해 더 나은 부호화 효율을 보여 주고, 이전 레퍼런스 확장 계층이 네트웍 사정으로 전송되지 않았을 경우에도 제안하는 알고리듬은 거의 화질의 손실이 없이 복원할 수 있음을 보여준다.

• Proceedings of the Acoustical Society of Korea Conference
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• 1998.06e
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• pp.181-184
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• 1998

웨이브렛 변환은 신호나 영상을 분석하기 위한 다해상도 분해기법으로 사용되어 왔다. 웨이브렛 변환영역에서 신호는 스케일과 위치상의 크기로 표현된다. 이 변환영역에서는 신호나 영상의 주파수 성분들이 각각의 스케일에 따라서 분리되어 나타난다. 또한 각 변환영역은 신호나 영상의 공간적인 특성을 상당부분 포함하고 있다. 이러한 웨이브렛 변환의 특성은 푸리에 변화에 기초한 방법과는 달리, 에지와 잡음성분을 효과적으로 분리할 수 있는 정보를 우리에게 제공해 준다. 본 논문에서는 웨이브렛 변환영역의 각 스케일 특성과 공간적인 특성을 이용하여 영상의 잡음성분을 제거하였다. 잡음제거 기법의 성능평가를 위해 Wiener 필터링 방법과 비교하였다.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2011.04a
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• pp.127-130
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• 2011

본 연구에서는 나노입자와 고분자 기지 간에 공유결합을 형성시킨 나노복합재의 계면특성과 탄성계수에서 나타나는 크기효과를 고려하기 위해 분자동역학과 미시역학모델을 순차적으로 연계하는 멀티스케일 해석모델을 제안하였다. 나노입자의 체적분율이 동일한 5개의 나노복합재 셀에 대해, 입자의 표면 원자와 고분자 기지 간에 탄소로 구성된 공유결합을 생성시킨 후 분자동 역학 전산모사를 통해 탄성계수를 예측하였고, 공유결합이 존재하지 않는 나노복합재의 탄성계수와 이를 비교하여 계면의 물성증가와 탄성계수에서 나타나는 입자의 크기효과를 규명하였다. 향상된 계면의 특성을 연속체 해석 모델에서 고려하기 위해 분자동역학 해석결과와 미시역학 모델을 연계하는 순차적 브리징 기법을 적용하였고, 이로부터 계산된 계면의 물성의 타당성을 유한요소 해석을 통해 검증하였다. 그 결과 입자와 기지 간 공유결합을 통해 나노복합재가 보다 넓은 범위에 걸친 크기효과를 나타냈으며, 제안된 브리징 모델을 통해서 물리적으로 타당한 계면의 탄성계수 값을 계산할 수 있었다.

• Proceedings of the Korean Fiber Society Conference
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• 1998.10a
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• pp.114-117
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• 1998

양모의 수축은 양모를 습윤 처리할 때 양모 스케일의 모근과 모단방향의 마찰계수가 다르기 때문에 일어나는 현상이므로 양모의 스케일을 화학적으로 개질하여 두 방향의 마찰계수의 차를 감소시키면 양모의 수축을 감소시킬 수 있다. 이와 같은 원리로 방축효과를 주는 양모의 방축 가공제로는 90% 이상이 염소 또는 염소를 발하는 물질인데 이 가공으로 인한 폐수는 환경문제를 일으키는AOX를 함유하고 있어서 이를 대체하고자 하는 연구가 여러 곳에서 진행되고 있다. (중략)