• Title/Summary/Keyword: Technology 수렴성

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복합재료 블레이드 단면 해석 프로그램(KSec2D-AE) 신뢰성 검증

  • Kim, Hyeon-Sik;Bae, Jin-Gyu;Im, Tae-Hyeon;Hwang, Jae-Min
    • Proceeding of EDISON Challenge
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    • 2017.03a
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    • pp.282-289
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    • 2017
  • 본 연구에서는 유한요소법 기반의 단면 특성치 해석 프로그램인 EDISON Software 'KSec2D-AE'의 정확성을 검증함으로써, 학부 수준의 비행체 구조해석 및 설계 시 활용가능성을 제시하고자 한다. 이를 위하여, 다양한 요소를 적용해가며 'KSec2D-AE'로부터 계산된 단면강성계수 결과의 요소개수에 따른 수렴성을 확인하였다. 또한 상용 구조해석프로그램인 'MSC NASTRAN'으로부터 구한 하중-변위 계산식을 통해 얻어진 강성계수와 비교하고, 하중을 적용하였을 시 각 중심치(tension center, shear center, principal bending axes)의 특성에 부합하게 구조물이 거동하는지 확인함으로써 'KSec2D-AE'의 단면강성계수 및 중심치 결과를 검증하였다. 그 결과를 통하여 'KSec2D-AE' 프로그램의 유용성을 확인하였다.

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A Boundary Integral Approximation for Bending of Elastic Plates (탄성평판 굽힘문제를 위한 경계적분 근사해)

  • Kim, Jin Woo
    • Journal of the Korea Institute of Military Science and Technology
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    • v.5 no.4
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    • pp.57-66
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    • 2002
  • 본 연구는 굽힘 하중하에서 탄성평판 구조 해석을 위한 경계적분방법 구성을 주목적으로 하고 체계적인 모듈화시스템 개발의 첫 이론 부분을 확립하였다. 굽힘 문제에서의 4개의 고유변수인 처짐, 기울기, 굽힘모우멘트, 상당 전단력의 항으로 경계적분방정식을 구성하였다. 물리적인 의미를 갖는 두 새로운 핵함수 도입으로 구성된 이들 적분방정식은 경계요소 구성시 나타나는 특이거동의 문제점을 간단한 두 탄성해에 의해 정규화 시켰으며 수치 적분 과정도 Cauchy 주치 적분 수렴성에서의 특별취급과는 달리 효율적으로 일반화시켰다. 경계적분식의 수치해석방법을 서술하였으며 집중하중하의 비대칭문제의 근사수치해를 도시하였다.

Blockchain E-voting System and Governance: The Case of Korean National Pension Service (블록체인 기술을 활용한 전자투표시스템과 지배구조: 국민연금 사례를 중심으로)

  • Chung, Hae Jin
    • The Journal of Society for e-Business Studies
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    • v.24 no.4
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    • pp.1-16
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    • 2019
  • Blockchain technology prevents tampering of central authorities that manage voting process, enhancing trust in the vote results. This technology enables citizens to participate more directly in the areas where delegation was inevitable due to the difficulties in polling fair and trustworthy public opinions. There are many projects around the world proposing to implement voting system for public decision making using blockchain technology. The blockchain voting system is expected to work as a transparent and fair channel for polling public opinions, which will transform the public decision-making process and governance. Korean National Pension Service (NPS) recently introduced stewardship code to better represent the interest of beneficiaries. However, because of the mistrust in governance of NPS, introduction of stewardship code is facing criticism for potential misuse of their voting rights against the interest of beneficiaries and for government's interference with corporate management. This study proposes a voting system applying blockchain technology for polling the opinions of National Pension Fund's beneficiaries to support public decision-making, and discusses social and institutional conditions for implementation of the proposed system.

An adaptive controller with fuzzy compensator for nonlinear time-varying systems (비선형 시변 시스템을 위한 퍼지 보상기를 가진 적응 제어기)

  • Park, Geo-Dong;Jeon, Wan-Su;Kim, Jong-Hwa;Lee, Man-Hyeong
    • Journal of Institute of Control, Robotics and Systems
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    • v.3 no.2
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    • pp.149-155
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    • 1997
  • 본 논문에서는 비선형 시변 시스템을 제어할 경우 제어시스템의 안정성을 보장하고 성능을 향상시키기 위한 새로운 적응제어 구조를 전개하였다. 주어진 플랜트가 선형 시불변이라는 가정하에 표준 기준 모델 적응제어기가 적용될 경우 발생되는 출력오차는 플랜트의 비선형 시변특성으로 인하여 점근적으로 0에 수렴되지 않는다. 이때 미지의 출력오차를 점근적으로 0에 수렴시키는 방법으로 퍼지보상기를 사용하였으며 결과적으로 플랜트의 비선형 시변 특성을 보상하는 효과를 얻을 수 있었다. 퍼지 보상기로는 출력오차등의 조건에 따라 이득이 변하는 퍼지 PID 보상기를 도입하여 안정하게 설계되도록 노력하였다. 또한 출력오차를 점근적으로 0에 수렴시키는 것은 표준 기준 모델 적응제어기 내부의 모든 파라미터와 신호가 유한하게 됨을 의미하기 때문에, 제어시스템 전체의 안정도를 보장할 뿐만 아니라 결과적으로 과도응답 성능을 향상시킬 수 있게 되었다. 몇가지 예제를 대상으로 시뮬레이션을 수행하고 그 결과를 분석함으로써 비선형 시변 시스템을 제어할 경우 본 논문에서 전개된 새로운 적응제어 구조의 타당성을 확인하였다.

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On Lp(T2)-Convergence and Móricz (Lp(T2)-수렴성과 모리츠에 관하여)

  • LEE, Jung Oh
    • Journal for History of Mathematics
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    • v.28 no.6
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    • pp.321-332
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    • 2015
  • This paper is concerned with the convergence of double trigonometric series and Fourier series. Since the beginning of the 20th century, many authors have studied on those series. Also, Ferenc $M{\acute{o}}ricz$ has studied the convergence of double trigonometric series and double Fourier series so far. We consider $L^p(T^2)$-convergence results focused on the Ferenc $M{\acute{o}}ricz^{\prime}s$ studies from the second half of the 20th century up to now. In section 2, we reintroduce some of Ferenc $M{\acute{o}}ricz^{\prime}s$ remarkable theorems. Also we investigate his several important results. In conclusion, we investigate his research trends and the simple minor genealogy from J. B. Joseph Fourier to Ferenc $M{\acute{o}}ricz$. In addition, we present the research minor lineage of his study on $L^p(T^2)$-convergence.

Analysis I of Operator Adaptive Characteristic in the Noisy-Blurred Images: Gaussian blurred and additive 20dB noise (훼손된 영상에서의 연산자 적응 특성 분석 I : 가우시안으로 흐려지고 20dB 잡음이 추가된 훼손된 영상)

  • Jeon, Woo-Sang;Han, Kun-Hee
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.11 no.5
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    • pp.1685-1692
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    • 2010
  • The Laplacian operator is usually used as a regularization operator which may be used as any differential operator in the regularization iterative processing. In this paper, several kinds of differential operator and proposed operator as a regularization operator were compared with each other performance. For noisy gaussian-blurred images, proposed operator worked better in the edge, while in flat region the conventional operator resulted better. In regularization, smoothing the noise and restoring the edges should be considered at the same time, so the regions divided into the flat, the middle, and the detailed, which were processed in separate and compared.

Relative Sweetness of Sucralose in Beverage Systems and Sensory Properties of Low Calorie Beverages Containing Sucralose (음료 system에서 수크랄로스의 상대당도 및 수크랄로스를 함유한 저열량 음료의 관능적 특성)

  • Kim, Mi-Young;Cho, Hea-Young;Park, Jae-Yeon;Lee, Soh-Min;Suh, Dong-Soon;Chung, Seo-Jin;Kim, Hee-Sup;Kim, Kwang-Ok
    • Korean Journal of Food Science and Technology
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    • v.37 no.3
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    • pp.425-430
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    • 2005
  • Relative sweetness of sucralose, an intensive sweetener, to sucrose or fructose in binary model solution and beverage systems was examined. Sensory properties of sucralose solution, orange flavored beverage and sports drink containing sucralose were evaluated at the equi-sweetness to sucrose or fructose. Consumer acceptability tests were performed on orange flavored beverage. Relative sweetness of sucralose to sucrose was 350 and 500 in binary model solution and orange flavored beverage, respectively, while that of sucralose to fructose in sports drink was 550. All the sensory properties, except astringency, of sucralose solution examined were similar to those of sucrose solution. The sensory properties of orange flavored beverage, in which 50% sucrose was replaced with sucralose, were very close, and showed comparable or higher overall acceptability to that containing sucrose only. When fructose was replaced with sucralose in sports drink sour, salty and bitter tastes, metallic flavor, and astringency slightly increased.

Analysis of Correlation between Geometry Elements for the Efficient Use of Satellite Stereo Images (효율적인 스테레오 위성자료 활용을 위한 기하요소 간 상관성 분석)

  • Jeong, Jaehoon
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.34 no.5
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    • pp.471-478
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    • 2016
  • This paper proposes the results of analysis of correlation between satellite geometry elements for an effective use of satellite images. To achieve accurate positional information, stereo images have normal range of convergence and BIE (BIsector Elevation) angles which are greatly influenced by azimuth and elevation angle of individual image. In this paper, the variations of convergence and BIE angles are estimated according to azimuth angle differences between two images and each elevation angle. The analysis provided strong support for predicting stereo geometry without complex analysis of epiploar geometry or mathematics. The experiment results showed that more than 150°, 130°, and 100° azimuth angle differences need to be constructed when elevation angle of two images is 50°, 60°, and 70°, respectively, in order to make the convergence and BIE angle within normal range. The results are expected to be fully used for various application using stereo images.

기상 탑재체의 Star Sensing 기능을 이용한 정지궤도 위성의 궤도결정 기술 연구

  • Kim, Bang-Yeop;Lee, Ho-Hyung
    • Aerospace Engineering and Technology
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    • v.4 no.2
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    • pp.88-93
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    • 2005
  • A conceptual study about the angle information based orbit determination technique for a geostationary satellite was performed. With an assumption that the simultaneous observing of the earth and nearby stars is possible, we confirmed that the view angles between the earth and stars can be use as inputs for orbit determination process. By the MATLAB simulation with least square method, the convergence is confirmed. This conceptual study was performed with the COMS for instance. This technique will be able to use as a back-up of ground station's orbit determination or a part of autonomous satellite operation.

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R&D기반 성장모형의 실증분석

  • 조상섭;정동진;장송자
    • Journal of Technology Innovation
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    • v.10 no.2
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    • pp.91-105
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    • 2002
  • This paper extends the empirical analysis on R&D based growth model so that the nonstationary panel unit root testing methods can be used to distinguish the exogenous growth model and R&D based growth model for the 1981-1999 period with fourteen OECD economies including Korea. Our results show that first, using U.S. and Group mean as benchmarking, the stochastic R&D productivity convergence to benchmarking is not supported in our data set. Second, the empirical results for stochastic nonconvergence to the U.S. or group mean also are robustness to panel unit root methods. We, therefore, find strong support for the implications for R&D based growth model.

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