• Proceedings of the Korean Society of Food Hygiene and Safety Conference
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• 2004.05a
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• pp.232-232
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• 2004

• Journal of the Korea institute for structural maintenance and inspection
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• v.7 no.1
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• pp.131-138
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• 2003

This paper presents an analytical prediction of the prestress losses of prestressed concrete bridges. In this study a numerical procedure and computer program is developed to analyze the behavior of prestressed concrete bridges considering the time-dependent properties of material. It accounts for the aging, creep and shrinkage of concrete and the stress relaxation of prestressed steel. The structural model uses two dimensional plane frame elements with three nodal degree of freedom and is analyzed based on the finite element method. Member cross section can consist of concrete, reinforcement and prestressing steel. Two different set of equations for the prediction of time-dependent material properties of concrete are presented, which are ACI, CEB-FIP. The proposed numerical method for the prestress losses of prestressed concrete bridges is verified by comparison with reliable experimental results.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.224-224
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• 2014

최근 기존의 아연 도금 강판의 성능을 향상시키기 위하여 다른 금속과의 합금 박막의 연구가 활발히 진행 중에 있다. 기존 아연 도금 강판에 비해 Mg를 함유한 Zn-Mg 합금 박막이 내식성이 우수하다고 알려져 있으며, 본 연구에서는 다양한 Mg 함량의 Zn-Mg 합금 타겟을 사용하여 Zn-Mg 박막을 합성하였다. 합성된 박막들의 내식성을 평가하기 위해서 Electrochemical Impedance Spectroscopy (EIS) 분석을 실시하였으며, 도출된 Nyquist plot 과 Bode phase angle plot 결과를 등가회로 피팅과 시뮬레이션을 실시하여 Mg 함량에 따른 Zn-Mg 박막의 내식성을 비교 분석하였다. Zn-Mg 박막은 Mg 함량이 증가할수록 내식성 또한 증가하였으며, 이는 Mg 함량에 따라 치밀해지는 미세구조에 의한 것으로 판단된다.

• Journal of Korea Foundry Society
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• v.13 no.6
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• pp.555-562
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• 1993

A study was investgated the relationship between fracture characteristics and microstructure changes according to Cu addition and heat treatment methods on the ductile cast iron. According to increment of Cu addition pearlite volume fraction was increased due to the deffect of anti-ferritizing of Cu. At the case of austempering heat treatment, fracture toughness of Cu contained specimen was decreased. The reason for the results seems to be responsible for decrement of plastic zone size at the crack tip. It was observed that the excellent fracture toughness can be obtained at the condition of normalizing and the specimen was not contained Cu. Under the such conditions, fractographs is composed of dimple pattern and fracture toughness 71.6MPa $\sqrt{m}$, tensile strength determined as the value of 961.6MPa, respectively.

• Proceedings of the KIEE Conference
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• 1998.07b
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• pp.750-753
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• 1998

This paper gives a simple parameterization of all stable unbiased filters to solve the suboptimal mixed $H_2/H_{\infty}$ filtering problem. Using the central filter, mixed $H_2/H_{\infty}$ filter is designed which minimizes the upper bound for the $H_2$ norm of the transfer matrix from a white noise to the estimation error subject to an $H_{\infty}$ norm constraint on the transfer matrix from an energy-bounded noise to the estimation error. The problem of finding suitable estimator gain can be converted into a convex optimization problem involving linear matrix inequalities.

• Proceedings of the KIEE Conference
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• 1998.07b
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• pp.436-439
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• 1998

In this paper, we propose a centralized $H^{\infty}$ state estimator for the multi state estimation problem using the result suboptimal $H^{\infty}$ filter is a special form of Ka filter whose state equations are defined in md inner product spaces. Con- ventional decentr filters are based on Kalman filter assumes precesses and measurements noises are w Gaussian noise. Therefore, Kalman based decent filter design hasn't robust performance in situation. Simulation results show that decent $H^{\infty}$ filter has robust perfotmance in worst case sensor fault situation.

• Proceedings of the Safety Management and Science Conference
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• 2011.04a
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• pp.177-183
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• 2011

Korea has performed strategies for the third industrial accident prevention in order to minimize industrial accident. However, the occupational fatality rate and industrial accident rate appears to be stagnated for 11 years. Therefore, this paper forecasts the occupational fatality rate and industrial accident rate for 10 years. Also, this paper applies regression method (RA), exponential smoothing method (ESM), double exponential smoothing method (DESM), autoregressive integrated moving average (ARIMA) model and proposed analytical function method (PAFM) for trend of industrial accident. Finally, this paper suggests fundamental strategies for industrial accident prevention by forecasting of industrial accident rate in the long term.

• Bulletin of the Korean Chemical Society
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• v.33 no.1
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• pp.159-166
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• 2012

We have introduced the Pickering emulsion systems to generate novel confining geometries for the selforganization of monodisperse polymer microspheres using nanoparticle-stabilized emulsion droplets encapsulating the building block particles. Then, through the slow evaporation of emulsion phases by heating, these microspheres were packed into regular polyhedral colloidal clusters covered with nanoparticle-stabilizers made of silica. Furthermore, polymer composite colloidal clusters were burnt out leaving nonspherical hollow micro-particles, in which the configurations of the cluster structure were preserved during calcination. The selfassembled porous architectures in this study will be potentially useful in various applications such as novel building block particles or supporting materials for catalysis or gas adsorption.

• Proceedings of the Korean Society of Computer Information Conference
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• 2018.07a
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• pp.411-414
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• 2018

식정보사회로 전환되고 있는 현대 사회에서 국가 경쟁력을 기르기 위해 소프트웨어 교육이 중시되고 있고 이에 우리나라 교육부는 '2015 개정 교육과정'에 소프트웨어 교육을 포함시키고 있다. 초등학교에서는 건전한 정보윤리의식과 태도를 갖고 실생활 다양한 문제를 해결하는 절차를 이해하여 컴퓨팅 사고에 대한 기초 역량을 기르는 것을 목표로 하나 교육과정에서 확보된 17시간의 시수로는 정보윤리의식과 컴퓨팅 사고력 모두를 함양시키기는 어렵다. 이에 본 논문에서는 선행연구들을 통해 도덕성의 4구성요소와 컴퓨팅 사고력에 대해 알아보고 이 두 이론 모두 문제해결과정에 초점을 두고 있다는 공통점을 활용하여 초등 소프트웨어 융합교육을 통해 정보윤리의식과 컴퓨팅 사고력 모두 함양할 수 있는 지도의 실제를 연구해 보기로 하였다.

• Journal of the military operations research society of Korea
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• v.18 no.2
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• pp.44-55
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• 1992

According to the plan on Defense Computer Network, hundreds of troops and ten thousands of end users will be joined in the Defense Computer Networn the near future. Thus, we need hierarchical addressing methods between source station and destination station in order to send a message efficiently. On the basis of the above background, we proposed the addressing methods for both TCP/IP environment which is a current standard protocol and OSI environment which will be a future protocol in this paper. The network interface. routings and address management have considered in our proposed addressing methods.