• the USERS
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• s.47
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• pp.32-33
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• 2006

정부는 2006년 1월 정보통신 R&D 사업을 확정하고 IT839 전략의 가속화를 중점 추진하는 내용의 투자계획안을 확정하였다. 이를 위해 기술개발에 7,067억원, 인력양성 부문에 1,145억원, 표준화에 335억원, 연구기반조성에 1,078억원 등 전년대비 10.1% 증가한 통 9,634억원을 투입할 계획이다.

• Journal of the Korean Mathematical Society
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• v.52 no.4
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• pp.839-851
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• 2015

A *-ring R is called (strongly) *-clean if every element of R is the sum of a projection and a unit (which commute with each other). In this note, some properties of *-clean rings are considered. In particular, a new class of *-clean rings which called strongly ${\pi}$-*-regular are introduced. It is shown that R is strongly ${\pi}$-*-regular if and only if R is ${\pi}$-regular and every idempotent of R is a projection if and only if R/J(R) is strongly regular with J(R) nil, and every idempotent of R/J(R) is lifted to a central projection of R. In addition, the stable range conditions of *-clean rings are discussed, and equivalent conditions among *-rings related to *-cleanness are obtained.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.8
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• pp.839-844
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• 2009

In this paper, a real-time eye tracking method using fast face detection is proposed. Most of the current eye tracking systems have operational limitations due to sensors, complicated backgrounds, and uneven lighting condition. It also suffers from slow response time which is not proper for a real-time application. The tracking performance is low under complicated background and uneven lighting condition. The proposed algorithm detects face region from acquired image using elliptic Hough transform followed by eye detection within the detected face region using Haar-like features. In order to reduce the computation time in tracking eyes, the algorithm predicts next frame search region from the information obtained in the current frame. Experiments through simulation show good performance of the proposed method under various environments.

• Smart Structures and Systems
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• v.18 no.5
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• pp.839-864
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• 2016

This paper presents an efficient method for updating the structural finite element model. Model updating is performed through minimizing the difference between the recorded acceleration of a real damaged structure and a hypothetical damaged one. This is performed by updating physical parameters (module of elasticity in this study) in each step using iterative process of modified nonlinear conjugate gradient (M-NCG) and modified Broyden-Fletcher-Goldfarb-Shanno algorithm (M-BFGS) separately. These algorithms are based on sensitivity analysis and provide a solution for nonlinear damage detection problem. Three illustrative test examples are considered to assess the performance of the proposed method. Finally, it is demonstrated that the proposed method is satisfactory for detecting the location and ratio of structural damage in presence of noise.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.8
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• pp.839-846
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• 2007

Nd:YAG pulse laser fillet welding of stainless steel plate was simulated to find welding condition by using commercial finite element code MARC. Full model of AISI 304 stainless steel plate was considered and user subroutines were applied to boundary condition for the heat transfer. Material properties such as conductivity, specific heat, mass density and latent heat were given as a function of temperature. As results, Three dimensional heat source model for pulse laser beam conditions of fillet welding has been designed by the comparison between the finite element analysis results and experimental data on AISI 304 stainless steel plate. Nd:YAG laser welding for AISI 304 stainless steel was successfully simulated and it should be useful to determine optimal welding condition.

• Korean Journal of Metals and Materials
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• v.49 no.11
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• pp.839-844
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• 2011

We examined the effects of alloying elements such as Fe, Ga, In, Sn, Mg, and Mn on the electrochemical characteristics of Al-based alloys for Al-air batteries by potentiodynamic polarization tests and electrochemical impedance spectroscopy. The corrosion potential of an Al anode was lowered by the addition of Ga and Sn, resulting in an increase in the cell voltage compared with a pure Al electrode. Fe was not beneficial to improve the electrochemical properties of the Al anode in that it caused a decrease in the cell voltage and reduced corrosion rate slightly. In, Mn, Sn, and Mg decreased the corrosion rate of the Al alloys, while Ga enhanced corrosion significantly and accelerated consumption of the anode.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.11a
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• pp.839-840
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• 2009

지능 로봇 분야의 발전은 빠른 속도로 성장하고 있으며 여러 환경에서 문제 해결을 할 수 있는 로봇에 대한 연구 또한 활발하게 이루어지고 있다. 지능 로봇을 구현하기 위해서는 주변 환경을 받아들이기 위한 센서 조작이 반드시 필요한데, 비용 면이나 생산량의 한계 등의 이유로 이러한 센서들을 일반 교육자, 학생이 접하기가 쉽지 않다. 본 논문에서는 3D 시뮬레이션 환경에서 다중 센서를 이용한 문제해결 로봇을 구현하는 개발 방법을 제안하고자 한다. 만약 3D 시뮬레이션 환경에서 손쉽게 센서의 생성과 조작이 가능하다면 지능 로봇 연구분야, 특히 지능로봇 교육분야에 큰 도움이 될 것으로 기대한다.

• Structural Engineering and Mechanics
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• v.47 no.6
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• pp.839-856
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• 2013

Metallic annular discs with their outer boundary fully constrained are studied with newly derived semi-analytical solutions for the effects of thickness variations under thermal loading and unloading. The plane stress and axisymmetric assumptions were adopted, and the thickness of the disk depends on the radius hyperbolically with an exponent n. Furthermore, it is assumed that the stress state is two dimensional and temperature is uniform in the domain. The solutions include the elastic, elastic-plastic and plastic-collapse behavior, depending on the values of temperature. The von Mises type yield criterion is adopted in this work. The material properties, Young's modulus, yield stress and thermal expansion coefficient, are assumed temperature dependent, while the Poisson's ratio is assumed to be temperature independent. It is found that for any n values, if the normalized hole radius a greater than 0.6, the normalized temperature difference between the elastically reversible temperature and plastic collapse temperature is a monotonically decreasing function of inner radius. For small holes, the n values have strong effects on the normalized temperature difference. Furthermore, it is shown that thickness variations may have stronger effects on the strain distributions when temperature-dependent material properties are considered.

• IT SoC Magazine
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• s.10
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• pp.33-39
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• 2006

정보통신부 IT839 차세대성장동력 사업중 IT SoC 및 부품 분야의 2006년도 선도과제 신규기획 방향을 소개한다. 본문에서는 신규과제의 추진배경 및 관련산업의 현황분석을 간략히 다루고, 이에 따른 기획방향 및 추진과제에 대해 기술한다. 관련 산업체/연구소/대학의 많은 참여로 경쟁력 있는 수행기관이 선정되고, 성공적인 R&D를 위한 힘찬 출발이 될 수 있기를 기대한다. (2006년 1월 11일경 사업공고 예정)

• Korea Information Processing Society Review
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• v.11 no.4
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• pp.83-88
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• 2004

최근 정부의 839 프로젝트(8개의 비즈니스모델, 3개의 인프라, 9개의 핵심기술)와 정보통신부 9대 신성장 동력산업에 텔레매틱스가 포함되면서 IT, 전자, 통신, 자동차 업계를 중심으로 텔레매틱스에 대한 관심이 높아지고 있다. 더욱이 텔레매틱스가 컨버전스 산업의 전형적인 대표 모델로 손꼽히고 있어 이러한 관심은 더 나아가 기술 및 산업의 활성화로 이어질 가능성이 매우 높을 것으로 생각된다. (중략)