• 천문학회보
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• 제36권1호
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• pp.53.2-53.2
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• 2011

A small number of active galactic nuclei are known to exhibit prominent double peak emission profiles indicating the presence of a relativistic accretion disk model. Using a Monte Carlo technique, we compute the linear polarization of a double peaked broad emission line. A Keplerian accretion disk is adopted for the double peak emission line region and the Schwarzschild geometry is assumed in the emission region. Far from the accretion disk where flat Minkowski geometry is appropriate, we place a scattering region in the shape of a spherical shell sliced. We generate a line photon in the accretion disk in an arbitraray direction in the local rest frame and follow the geodesic of the photon until it hits the scattering region. The profile of the polarized flux is mainly determined by the relative location of the scattering region with respect to the emission source. When the scattering region is in the polar direction, the linear degree of polarization also shows a double peak structure. Under a favorable condition we show that up to 1% of linear degree of polarization may be obtained.

• 한국해양학회지
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• 제24권1호
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• pp.29-38
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• 1989

동해 해수순환의 특징은 대한해협으로부터 유입된 난수가 동한난류를 형성하여 한국연안을 따라 북상한 후 다시 외해로 분리되어 나간다는 것과 북쪽에서부터 연안을 따라 남하하는 북한한류가 형성하는 반시계 방향의 순환류가 동해 북부에 존재한다는 사실일 것이다. 본 논문에서는 이러한 사실을 설명하기 위하여 간단한 역학적 모델을 수립하였다. 동해 해수순환을 기본적으로 유입-유출 형태라 한 후 여기에 해양-대기 열 교환을 적용하였으며 해수혼합에 의한 열의 소멸, 마찰에 의한 운동량의 소멸도 고려하였다. 결과에 의하면, 상기의 순환특징은 열역학적 요인에 의하여 기인됨이 밝혀졌다. 또한, 열교환의 정도에 따라 여러가지 순환형태가 나타날 수 있음도 보였다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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• pp.75-80
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• 2002

The mainly used technique to rectify satellite images with distortion is to develop a mathematical relationship between the pixel coordinates on the image and the corresponding points on the ground. By defining the relationship between two coordinate systems, a polynomial model is designed and various linear transformations are used. These GCP based geometric correction has performed overall plane to plane mapping. In the overall plane mapping, overall structure of a scene is considered, but local variation is discarded. The highly variant height of region is resampled with distortion in the rectified image. To solve this problem this paper proposed the TIN-based rectification on a satellite image. The TIN based rectification is good to correct local distortion, but insufficient to reflect overall structure of one scene. So, this paper shows the experimental result and the analysis of each rectification model. It also describes the relationship GCP distribution and rectification model. We can choose a geometric correction model as the structural characteristic of a satellite image and the acquired GCP distribution.

• Earthquakes and Structures
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• 제24권6호
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• pp.393-404
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• 2023

This paper presents the application of hybrid-simulation-based adapter elements for the non-linear two-scale analysis of reinforced concrete frames with masonry infills under seismic-like demands. The approach provides communication and distribution of the computations carried out by two or more remote or locally distributed numerical models connected through the OpenFresco Framework. The modeling consists of a global analysis formed by macro-elements to represent frames and walls, and to reduce global degrees of freedom, portions of the structure that require advanced analysis are substituted by experimental elements and dimensional couplings acting as interfaces with their respective sub-assemblies. The local sub-assemblies are modeled by solid finite elements where the non-linear behavior of concrete matrix and masonry infill adopt a continuum damage representation and the reinforcement steel a discrete one, the conditions at interfaces between concrete and masonry are considered through a contact model. The methodology is illustrated through the analysis of a frame-wall system subjected to lateral loads comparing the results of using macro-elements, finite element model and experimental observations. Finally, to further assess and validate the methodology proposed, the paper presents the pushover analysis of two more complex structures applying both modeling scales to obtain their corresponding capacity curves.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 B
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• pp.923-928
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• 1993

Genetic algorithms are powerful optimization methods based on the mechanism of natural genetics and natural selection. Genetic algorithms reduce chance of searching local optima unlike most conventional search algorithms and especially show good performances in complex nonlinear optimization problems because they do not require any information except objective function value. This paper presents a new model based on sexual reproduction in nature. In the proposed Sexual Reproduction model(SR model), individuals consist of the diploid of chromosomes, which are artificially coded as binary string in computer program. The meiosis is modeled to produce the sexual cell(gamete). In the artificial meiosis, crossover between homologous chromosomes plays an essential role for exchanging genetic informations. We apply proposed SR model to optimization of the design parameters of Single-sided Linear Induction Motor(SLIM). Sequential Unconstrained Minimization Technique(SUMT) is used to transform the nonlinear optimization problem with many constraints of SLIM to a simple unconstrained problem, We perform optimal design of SLIM available to FA conveyer systems and discuss its results.

• 한국정보과학회논문지:소프트웨어및응용
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• 제36권10호
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• pp.816-824
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• 2009

얼굴영상 공간에서 얼굴영상들은 조명이나 포즈에 의해 비선형적 분포를 갖는다. 이들을 선형모델에 기반을 둔 AAM으로 모델링 하는 것은 한계가 있다. 본 논문에서는 얼굴영상에 대한 몇 개의 군집이 주어졌다고 가정하고, 각 군집 별로 지역적인 AAM 모델을 구축하여 정합과정 중에 적합한 모델이 선택되도록 한다. 정합과정에서 발생하는 모델변경에 따른 모델간의 정합 인자 갱신의 문제는 인자 공간에서 모델간의 선형 관계를 미리 학습하여 해결한다. 심각한 정합 실패에 따른 잘못된 모델 선택을 줄이기 위해 점진적으로 모델변경이 이루어지도록 한다. 실험에서는 제안하는 방법을 Yale-B 조명얼굴 영상에 적용하여 모델을 생성하고 기존 방법과 정합 성능을 비교한다. 제안 방법은 심각한 그림자가 발생하는 강도 높은 조명얼굴 영상에서 성공적인 정합 결과를 보여주었다.

• 제어로봇시스템학회논문지
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• 제7권1호
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• pp.1162-1170
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• 2001

This paper proposes a practical gain-scheduling control law considering robust stability and performance of Linear Parameter Varying(LPV) systems in the presence of nonlinearities and uncertainties. The proposed method introduces LMI-based pole placement synthesis and also associates with a recently developed fuzzy control system based on Takagei-Sugenos fuzzy model. The sufficient conditions for robust controller design of linearized local dynamics and robust stabilization of fuzzy control systems are reduced to a finite set of Linear Matrix inequalities(LMIs) and solved by using co-evolutionary algorithms. The proposed method is applied to the longitudinal acceleration control of high performance aircraft with linear and nonlinear simulations.

• 한국가구학회지
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• 제21권1호
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• pp.26-39
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• 2010

This is a leading study to replace the structural analysis methodology on the specific traditional joint by a numerical analysis. Tests were carried out to test the compressive methodologies with the numerical results. The Japanese larch was used as a sample. The Orthotropic property of wood was specifically considered for the finite element numerical analysis. Linear numerical analysis and non-linear numerical analysis for the BEAM element and the two SOLID elements of ANSYS were used to analyze the compressive performance. In addition, more finely divided elements were used to raise the accuracy of the numerical result. Finally, the statistically significant differences were tested between that of the analytical and numerical results. It could be concluded that the SOLID 64 element shows the most optimum result when the non-linear analysis with the more finely divided element was used. However, finely dividing of the element is a considerable time consuming process, and it is quite difficult to raise the accuracy of the non-linear numerical analysis. Therefore, if considering the vertical displacement to be of the only interest, the BEAM element is more efficient than the SOLID element because the BEAM element is reflected as a simple line, which is less time consuming and difficult in dividing the elements. But, the BEAM element cannot accurately model the knot as a strength defect factor which is an important property in the orthotropic property of wood. Therefore, the SOLID element should be used to model the strength defect factor, knot, as it can be efficiently applied on the structural size flexure member which could be more strongly effected by the knot. In addition, it is useful at times when the failure types of members are to be more closely investigated, as the SOLID element is able to examine the local stress distribution of the member. The conclusion drawn by this study is of the good concordance between analytical results and numerical results of compressive wood members, but how orthotropic properties should only be considered. The numerical analysis on the specific Korean traditional joints will be based on the current study results.

• 농촌계획
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• 제10권2호
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• pp.43-49
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• 2004

According to the growing concerns of the public with efficiency and effects of regional policies, their assessment works have become an important issue. Up to now, several studies have been carried out on economic effects of policies using conventional cost/benefit analysis, while there have been few studies on assessment of amenity oriented policies. From the above consideration, this study tried to develop An Annual Expenditure Assessment Model (AEAM) for amenity-oriented policy-making in rural area. As a pre-work for model development, the hierarchical indices system for rural development and the classification system of expenditure were designed. Being based on high significant relationship between rural amenities and local government expenditure, a linear optimization model for maximization of regional amenity was constructed. Through a case study of Sunchang-gun, Chonbuk-province, the model applicability was ascertained.

• 전자공학회논문지SC
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• 제42권1호
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• pp.13-21
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• 2005

본 논문에서는 시간지연과 입력포화를 갖는 카오스 시스템에 대한 퍼지 모텔 기반의 동기화 기법을 제안한다. 시간지연을 갖는 카오스 마스터 시스템과 슬레이브 시스템을 모델링하기 위해 Takagi-Sugeno(T-S) 퍼지 모델을 이용한다. 특히 슬레이브 시스템은 제어 입력이 제한되는 입력포화 특성을 갖는다고 가정한다. 선형 오차 피드백과 병렬 분상 보상(PDC) 방법에 따라 퍼지 카오스 동기화 시스템을 설계하고 동기화 오차 시스템의 국소 안정도 조건을 해석한다. 신호 전송 채널에는 시간지연이 항상 존재하므로 채널 시간지연 또한 고려한다. 입력포화와 시간지연을 갖는 퍼지 동기화 시스템의 국소 안정도에 대한 충분 조건은 Lyapunov-Krasovskii 이론을 적용하여 선형 행렬 부등식 (LMI) 문제의 해를 통해 얻어진다. 제안된 동기화 기법의 효과를 확인하기 위해서 모의 실험을 수행한다.