• 한국재료학회:학술대회논문집
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• 한국재료학회 2010년도 춘계학술발표대회
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• pp.37.2-37.2
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• 2010

Recently $Li_{1.2}Ni_{0.2}Mn_{0.6}O_2$ has been consistently examined and investigated by scientists because of its high lithium storage capacity, which exceeds beyond the conventional theoretical capacity based on conventional chemical concepts. Consequently, $Li_{1.2}Ni_{0.2}Mn_{0.6}O_2$ is considered as one of the most promising cathode candidates for next generation in Li rechargeable batteries. Yet the mechanism and the origin of the overcapacity have not been clarified. Previously, many authors have demonstrated simultaneous oxygen evolution during the first delithiation. However, it may only explain the high capacity of the first charge process, and not of the subsequent cycles. In this work, we report a clarified interpretation of the structural evolution of $Li_{1.2}Ni_{0.2}Mn_{0.6}O_2$, which is the key element in understanding its anomalously high capacity. We identify how the structural evolution of $Li_{1.2}Ni_{0.2}Mn_{0.6}O_2$ occurs upon the electrochemical cycling through careful study of electrochemical profiles, ex-situ X-ray diffraction (XRD), HR-TEM, Raman spectroscopy, and first principles calculation. Moreover, we successfully separated the structural change at subsequent cycles (mainly cation rearrangement) from the first charge process (mainly oxygen evolution with Li extraction) by intentionally synthesizing sample with large particle size. Consequently, the intermediate states of structural evolution could be well resolved. All observations made through various tools lead to the result that spinel-like cation arrangement and lithium environment are created and embedded in layered framework during repeated electrochemical cycling.

• 기술경영경제학회:학술대회논문집
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• 기술경영경제학회 1997년도 제11회 하계학술발표회 논문집
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• pp.124-159
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• 1997

This paper examines a significant example of accumulation of technology in post war Japan - the development process of the videocasstte recorder (VCR) for home use, and the dynamic evolution process of the mass market. The purpose of analyzing the Japanese home VCR industry is to clarify how and why only the Japanese makers had succeeded in developing home VCR and dominated. the global mass market and to make clear the dynamic process of industrial evolution. This study found out the following facts; 1) Japanese inter-firm interactions in the VCR have been carried out by the structure of "the competition and cooperation among the engaged players" form the initial stage, to growing, and maturing stage. 2) The process of competition and cooperation produced the revolutionary innovation through a continuous systematic development process in the R&D phase. 3) The process of competition and cooperation accelerated the speed of technological progress and the rapid growth of the industry in the growing and maturing stage.

• Journal of Information Processing Systems
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• 제15권6호
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• pp.1422-1437
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• 2019

With the rapid development of the Internet and the Mobile Internet, social communication based on the network has become a life style for many people. WeChat is an online social platform, for about one billion users, therefore, it is meaningful to study the spreading and evolution mechanism of the rumor on the WeChat social circle. The Rumor was injected into the WeChat social circle by certain individuals, and the communication and the evolution occur among the nodes within the circle; after the refuting-rumor-information injected into the circle, subsequently,the density of four types of nodes, including the Susceptible, the Latent, the Infective, and the Recovery changes, which results in evolving the WeChat social circle system. In the study, the evolution characteristics of the four node types are analyzed, through construction of the evolution equation. The evolution process of the rumor injection and the refuting-rumor-information injection is simulated through the structure of the virtual social network, and the evolution laws of the four states are depicted by figures. The significant results from this study suggest that the spreading and evolving of the rumors are closely related to the nodes degree on the WeChat social circle.

• Corrosion Science and Technology
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• 제19권3호
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• pp.156-162
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• 2020

The objective of this study was to investigate delayed oxygen evolution and localized corrosion resistance of titanium alloys by performing potentiodynamic polarization, potentiostatic polarization, and Mott-Schottky measurements. Delayed oxygen evolution was compared among titanium alloys, 316 stainless steel, and platinum. Difference in delayed oxygen evolution between titanium alloys and other metals was attributed to specific surface characteristic of each metal. Delayed oxygen evolution of titanium alloys resulted from the predominant process of ionic conduction over electronic conduction. The effect of oxygen evolution on localized corrosion of titanium alloys was investigated using electrochemical critical localized corrosion temperature (E-CLCT) technique. Mott-Schottky measurement was performed to clarify the difference in film properties between titanium alloys and stainless steels. Titanium alloys were found to have much lower donor density than stainless steels by 1/28. These results indicate that delayed oxygen evolution has little influence on the concreteness of passive film and the resistance to localized corrosion of titanium alloys.

• 소성∙가공
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• 제17권2호
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• pp.113-116
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• 2008

Computer simulation of microstructure evolution during hot forging process is of great interest in recent years. Recrystallization model and grain growth model which use a phenomenological approach were summarized. The upsetting and cogging processes of waspaloy were simulated using $DEFORM^{TM}$ and the change in grain size were investigated in each deformation procedure.

• 한국초등과학교육학회지:초등과학교육
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• 제25권4호
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• pp.352-362
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• 2006

학생들의 개념이 정규 교육 과정에서 배우기 이전의 경험에 의해 선개념이 형성하게 되며 선개념중 오개념들은 과학적 개념을 습득하는 것을 방해한다. 생물학에서 중요한 진화 개념은 특히 오개념이 많은 개념 중 하나이다. 진화에 대한 오개념의 형성 과정에서 TV만화와 아동 과학 도서의 영향이 있을 것으로 판단하여 분석해 보았다. TV 만화의 영향을 확인하기 위하여 TV 만화 속에 등장하는 캐릭터를 활용하여 검사지를 제작하고 초등학생 146명, 중학생 161명, 고등학생 156명에겐 투입하여 분석하고 아동 과학 도서는 16권의 책을 수집하여 진화적 설명이 어떤 형태로 되어 있는지 분석하였다. 연구 결과 아동은 TV 만화 속에서 진화라고 부르는 '성장', '변태' 과정을 진화로 알고 있었다. 그리고 진화의 의미로 '자라면서 변하는 것'의 응답이 매우 높았으며 이는 TV 만화의 영향을 해석된다. 일부 아동 과학 도서에서는 돌연변이, 자연 선택과 같은 개념을 포함시킨 도서도 있었지만 대부분의 아동 과학 도서에서는 진화적 설명으로 목적론적 설명, 내부 의지적 설명, 용불용설적 설명의 형태를 많이 사용하였다. 이는 진화 개념에서 학생들이 많은 오개념을 가지게 된 이유로 TV 만화와 아동 과학 도서 등을 통하여 유입된 잘못된 개념이 원인일 수 있다는 주장을 뒷받침한다. 그리고 TV 만화와 아동 과학 도서에 대한 검정 과정의 필요성을 인식하게 해준다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2007년도 춘계학술대회 논문집
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• pp.282-284
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• 2007

The hardening and the constitutive equation based on the crystal plasticity are introduced for the numerical simulation of hemispherical sheet metal forming. For calculating the deformation and the stress of the crystal, Taylor's model of the crystalline aggregate is employed. The hardening is evaluated by using the Taylor factor, the critical resolved shear stress of the slip system, and the sum of the crystallographic shears. During the hemispherical forming process, the texture of the sheet metal is evolved by the plastic deformation of the crystal. By observing the texture evolution of the BCC sheet, the texture evolution of the sheet is traced during the forming process. Deformation texture of the BCC sheet is represented by using the pole figure. The comparison of the strain distribution and punch force in the hemispherical forming process between crystal plasticity and experiment shows the verification of the crystal-based formulation and the accuracy of the hardening and constitutive equation obtained from the crystal plasticity.

• 기술혁신연구
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• 제31권2호
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• pp.83-110
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• 2023

이 연구는 정부의 사회문제 해결형 연구개발사업 진화과정을 통해 사회문제 해결형 R&D 모델이 한국 사회에 자리 잡는 과정을 분석한다. 기업, 과학기술계, 시민사회에도 없었던 사회문제 해결형 R&D 모델이 정부연구개발사업을 통해 형성되고 이 모델에 따라 혁신활동을 수행하는 조직공동체가 전개되는 과정을 살펴볼 것이다. 이를 위해 새로운 혁신모델인 사회문제 해결형 R&D 모델, 그것을 지원·수행하는 조직공동체, 새 모델을 지원하는 제도가 공진화하는 과정을 분석하는 개념적 틀을 제시한다. 그리고 이 틀을 기반으로 사회문제 해결형 연구개발사업이 진행되면서 새로운 혁신모델이 형성·발전되는 과정을 살펴보고 그 의미를 논의할 것이다. 종합에서는 사회문제 해결형 R&D 모델의 활성화를 위한 과제와 정책 방안을 다룬다.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2009년도 정보통신설비 학술대회
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• pp.221-224
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• 2009

In this paper, we deal with the development of an optimal design program for a dual-band of 0.92 GHz and 2.45 GHz with shorting pin and slot by using evolution strategy. the optimal shorting pin, coaxial feed and H-shaped patch are determined by using an optimal design program based on the evolution strategy. To achieve this, an interface program between a commercial EM analysis tool and the optimal design program is constructed for implementing the evolution strategy technique that seeks a global optimum of the objective function through the iterative design process consisting of variation and reproduction. The resonance frequencies of the dual-band antenna yielded by the optimal design program are 0.92 GHz and 2.45 GHz that show a good agreement to the design target values.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.165.1-165
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• 2001

The evolution strategy is a good evolutionary algorithm to find the global optimum of a real-valued function. Since many engineering problems can be formulated as real valued function optimization, the evolution strategy is frequently employed in engineering fields. However, in many engineering optimization problems, an optimization parameter is often restricted in the bounded region between two specified values, the minimum and the maximum limit, respectively. Since an offspring individual is generated randomly around a parent individual during mutation process of the evolution strategy, an individual outside the search region can be generated even if the parent is inside the search region. This paper proposes two new boundary-handling techniques for evolution strategies. One is the ...