• Proceedings of the Korean Information Science Society Conference
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• 1999.10b
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• pp.482-484
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• 1999

본 논문에서는 매개변수 없이 입력 문서 영상을 최대 동질 영역들로 분할한 다음, 각 동질 영역을 텍스트, 그림, 표 그리고 선으로 자동 분류하는 새로운 방법을 제안한다. 다단계 분석과 하향식 접근 방법을 사용하기 위하여 문서 영상을 피라미드 구조로 계층화하였으며, 어떤 영역을 분할할 지의 여부를 결정하기 위하여 그 영역의 주기성을 이용하여 판단하였다. 이러한 주기성 정보를 이용함으로써, 어떠한 매개변수 없이도 활자체 크기와 행간에 무관하게 텍스트 영역을 정확히 분석할 수 있었으며, 피라미드 구조를 만드는데 걸리는 시간이 질감 분석 접근방법보다 빠른 방법으로 설계되었다. Washington 대학의 문서 영상 데이터베이스를 이용한 실험 결과, 제안된 방법이 기존의 방법들보다 더 정확하게 문서 영상을 분할 및 분류할 수 있음을 확인할 수 있었다.

• Proceedings of the Korea Water Resources Association Conference
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• 1984.07a
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• pp.115-117
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• 1984

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.4
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• pp.93-101
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• 2004

A face boundary can be approximated by an ellipse with five-dimensional parameters. This property allows an ellipse detection algorithm to be adapted to detecting faces. However, the construction of a huge five-dimensional parameter space for a Hough transform is quite unpractical. Accordingly, we Propose a selectively attentional Hough transform method for detecting faces from a symmetric contour in an image. The idea is based on the use of a constant aspect ratio for a face, gradient information, and scan-line-based orientation decomposition, thereby allowing a 5-dimensional problem to be decomposed into a two-dimensional one to compute a center with a specific orientation and an one-dimensional one to estimate a short axis. In addition, a two-point selection constraint using geometric and gradient information is also employed to increase the speed and cope with a cluttered background. After detecting candidate face regions using the proposed Hough transform, a multi-layer perceptron verifier is adopted to reject false positives. The proposed method was found to be relatively fast and promising.

• The Journal of the Convergence on Culture Technology
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• v.8 no.3
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• pp.239-244
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• 2022

In this study, the key parameters affecting the deterioration of each track type were derived based on field inspections and laboratory tests. The existing track deterioration model was limited to the ballasted tracks, and the deterioration evaluation of concrete tracks was insufficient. In this study, the laboratory test was performed to evaluate the performance and condition of track components to derive the deterioration factors reflecting the characteristics of various track structures. In addition, through analysis of track maintenance history data, parameters affecting track deterioration and maintenance were derived. The key parameters for presenting a track deterioration model based on the track performance of ballasted and concrete tracks through field inspection, track maintenance history data analysis, and performance test of track components using on-site specimens were identified as track support stiffness, Ballast gravel, track settlement and Resilience pad were presented.

• Composites Research
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• v.16 no.1
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• pp.13-18
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• 2003

Prediction of composite fatigue life is not a straightforward matter, depending on various failure modes and their interactions. In this paper, a methodology is presented to predict fatigue life and residual strength of composite materials based on Phenomenological Model(non-linear fatigue damage model). It is assumed that the residual strength is a monotonically decreasing function of the number of loading cycles and applied fatigue stress ratio and the model parameters(strength degradation parameter and fatigue shape parameter) are assumed as function of fatigue life. Then S-N curve is used to extract model parameters that are required to characterize the stress levels comprising a randomly-ordered load spectrum. Different stress ratios (${\sigma}_{min}/{\;}{\sigma}_{max}$) are handled with Goodman correction approach(fatigue envelope) and the residual strength after an arbitrary load cycles is represented by two parameter weibull functions.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.45-45
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• 2015

고전전인 천수방정식을 적용한 도시침수 해석모형에서 건물의 영향을 고려한 정확한 해석을 수행하기 위해서는 고해상도 격자가 요구되며 이는 계산시간의 증가가 야기된다. 고전 천수방정식을 적용한 도시침수해석 모형의 이러한 문제점을 극복하기 위해서 본 연구에서는 도시지역에 존재하는 건물 체적에 레이놀즈 이송이론을 적용한 수정 천수방정식을 제안하고, 제안 천수방정식을 이용한 효율적인 2차원 도시침수해석 모형을 개발하였다. 도시지역의 침수 모델링을 위해 고전 천수방정식은 건물을 고려하기 위해 고해상도 격자를 사용하는 것과 달리 수정 천수방정식은 건물의 영향을 매개변수화함으로서 저해상도 격자의 사용에도 고전 천수방정식과 유사한 정확도를 얻을수 있다. 건물의 영향을 매개변수화하기 위해서는 건물로 인한 저류와 흐름방향의 변화를 지배방정식이 고려할 수 있도록 수정하였다. 즉. 수정 천수 방정식은 고전 천수방정식을 기본으로 하여 건물의 저류영향을 고려하기 위해 각 계산격자에 적용되는 체적 매개변수와 건물의 흐름방향을 고려하기 위해 흐름방향과 직각방향에 위치한 선분(격자를 구성하고 있는 경계선)에 적용되는 면적 매개변수가 추가된다. 수정 천수방정식을 검증하기 위해 개발모형을 건물이 균일하게 위치한 실험하도와 비균일하게 위치한 실험하도에 적용하고 그 결과를 고전 천수방정식을 사용한 계산결과 및 계산시간과 비교함으로서 개발모형의 정확성과 효율성을 검증하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.11
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• pp.1343-1350
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• 2019

Converting boundary images to time-series makes it feasible to perform boundary matching even on a very large image database, which is very important for interactive and fast matching. In recent research, there has been an attempt to perform fast matching considering partial denoising by converting the boundary image into time series. In this paper, to improve performance, we propose an index-building method considering all possible arbitrary denoising parameters for removing arbitrary partial noises. This is a challenging problem since the partial denoising boundary matching must be considered for all possible denoising parameters. We propose an efficient single index-building algorithm by constructing a minimum bounding rectangle(MBR) according to all possible denoising parameters. The results of extensive experiments conducted show that our index-based matching method improves the search performance up to 46.6 ~ 4023.6 times.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1993.10a
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• pp.21-27
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• 1993

매개변수가진에 종속되는 현의 횡방향진동을 시간영역에서 필터작업, 힐버트 변환과 순간주파수 개념을 도입하여 해석함으로서 종방향의 순간진동변위를 추정하는 방법이 제시되었다. 그리고, 실험을 통하여 이론의 타당성을 검증 하였다. 또한, 모의 실험의 결과 일반적인 현구동계에 있어서는 넓은 적용변 수의 선\ulcorner영역에서 종변위가 횡변위와 분리(decoupling) 되어서 공간적으로 길이에 따르는 선형적인 증가성과 시간적으로 조화적인 주기성을 가진다는 것을 확인함으로서 임의의 위치에서의 종변위를 파악함이 가능하였다.

• Journal of Advanced Marine Engineering and Technology
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• v.41 no.1
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• pp.111-117
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• 2017

The arrival time of rescue ships is very important in the event of distress. This paper presents the development of experimental data to calculate the arrival time of rescue ships. The ship's traffic probability distribution was used. Mokpo Port was selected as the area of study, and AIS data for a 1 year period were used. For the ship's traffic probability distribution, a gateline was established. The lateral range distribution was calculated and fitted to the normal distribution and two Gaussian mixture distributions (GMD2), and each parameter was extracted. After the locations of ${\mu}$, ${\mu}{\pm}1{\sigma}$ of the normal distribution and ${\mu}_1$ of the two Gaussian mixture distribution(GMD2) were set as waypoints, the location and probability were determined. A scenario was established in relation to each type of parameter. Thus, the arrival time can be calculated.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.21 no.4
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• pp.169-174
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• 2011

Nanoscale-biodegradable behaviors of synthesized biphasic calcium phosphates (BCP) powders were characterized using X-ray diffraction (XRD), lattice parameter, and field emission microscopy (FE-SEM). The calcined BCP powders in vitro tested in Hank's balanced salt solution (pH = 7.4, $36.5^{\circ}C$) for 3 weeks. The calculated unit cell parameters for BCP have shown lattice distortion and expansion as irregular changes in the a and c-axis after in vitro.