• Journal of the Korean Applied Science and Technology
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• v.30 no.4
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• pp.726-739
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• 2013

Fischer-Tropsch synthesis (FTS) converts synthesis gas (CO and $H_2$) into longer chain hydrocarbons by a surface polymerization reaction. Cobalt- or iron-based catalysts normally show excellent activity for syngas conversion to petroleum products leading to super clean diesel fuels. The catalytic activities of the catalysts in FTS depend on the number of active sites on the surface. The number of active site was determined by the active metal particle size, loading amount, reduction degree and support-active metal interaction. The investigation adopts new methodology in preparing FT catalyst, which contains the controlled synthesis of active metal. The main focus of this paper is to give an overview of the types of catalysts, also including their preparation and reduction; the types of FT reactors; and also including the reaction conditions.

• Proceedings of the Korea Technology Innovation Society Conference
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• 2017.11a
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• pp.569-589
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• 2017

최근 정부는 변화하는 환경에 조응하기 위한 혁신적인 국가 R&D 시스템의 도입 및 성과평가 준거 틀의 전환을 시도하고 있다. 이에 연구자 중심의 "정부 R&D 혁신방안(2015)"을 제안하고 기존의 추격형 R&D체제에서 벗어나 질적 우수성 추구로 패러다임 전환과 창의 도전적 R&D에 초점을 맞춘 평가방식, 그리고 행정시스템 간소화 등을 해결해야 할 주요 과제로 제안하고 있다. 하지만, 다양한 이해관계자가 제시한 지속적인 의견 등을 고려할 때, 변화 이슈에 대한 장기적인 R&D 시스템 전개방향은 공감되나, 실행단계에서 실효적 적용은 많은 논의가 필요해 보인다. 특히, 특정 집단의 이해관계를 벗어나기 힘든 경우, 편향된 이슈 및 정책 제안이 제시되거나, 제안된 정책 간 일관성 있는 논리를 설정하기 어렵거나, 불특정 다수의 이해관계자 집단 간 이익 대변 혹은 현실을 벗어나는 이상적인 방향을 제안하는 경우도 있다. 따라서 이해관계자를 넘어서는 통합적 관점에서 사회 전체적 여건을 고려하는 혁신적 국가 R&D 시스템에 대한 정책적 실행방안을 고민해 볼 필요성이 제기된다. 본 연구에서는 우리나라의 과학기술 혁신정책 및 R&D 성과, 주요국 관련 동향 등을 살펴보고 현행 R&D 추진 시스템을 사회 시스템 차원에서 바라보며, 제기되는 관련 이슈에 대한 비판적 담론과 쟁점을 정리 및 분석하였다. 또한, R&D 혁신주체 간 상호작용 및 추진 시스템 효율성 측면의 핵심 이슈를 분석하여 R&D 추진 시스템 중장기 구축방향과 한계도 체계적으로 살펴보았으며, 이를 정리한 실행전략을 제시하였다.

• Journal of Aerospace System Engineering
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• v.9 no.1
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• pp.12-18
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• 2015

The inter-conversion between different control laws in flight has a lot of risk. The SWM(Switching Mechanism) including logic and stand-by mode is designed to analyze the transient response of aircraft during inter-conversion between different control laws, based on the in-house software for non-real-time and real-time simulation. The SWM applies the fader logic of TFS(Transient Free Switch) to minimize the transient response of an aircraft during the inter-conversion, and applies the reset '0' type of the stand-by mode to prevent surface saturation due to integrator effect in the disengaged flight control law. The transition time is also important to minimize the objectionable transient response in the inter-conversion, as well as the transition control law design. This paper addresses the results of non-real-time simulation for the characteristics of transient response to different transition time to select the adequate transient time, and the real-time pilot evaluation, using SSWM(Software Switching Mechanism) and HSWM(Hardware Switching Mechanism), which is met for Level 1 flying qualities and assures safety of flight.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.1
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• pp.189-194
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• 2012

This paper is about frequency allocation of LTE Base Station(BS) in the spare band which is generated by DTV transition. In the case of frequency allocation of LTE BS in adjacent band with DTV channel 51 among the spare band, the guard bands that requires for no interference between LTE and DTV system were calculated. As a result, 5.5 MHz of guard band for LTE BS and 2 MHz of guard band for DTV receiver were suggested based on interference analysis between LTE BS and DTV BS, respectively.

• Journal of the Economic Geographical Society of Korea
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• v.17 no.3
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• pp.567-584
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• 2014

This paper attempts to analyze labor politics under the Kim Young-Sam regime. The labor politics transformed from conflictual pluralism to social partnership. The transition was triggered by the 'IMF economic crisis,' and the transitional direction was determined by the character of political regime and the pattern of social coalitions. These findings imply that the transitional direction of labor politics is not determined by an economic crisis or international pressure, but by the relational dynamics of social coalitions forcing social actors to new perception and strategic choice.

• 한국벤처창업학회:학술대회논문집
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• 2022.11a
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• pp.83-88
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• 2022

디지털 전환은 기존 산업의 진입장벽 파괴에 따른 새로운 비즈니스 기회 확대, 자산의 디지털화에 따른 초기창업비용의 축소 등 창업 및 기업가적 활동 측면에서 중대한 환경적 변화를 초래하고 있다. 이러한 변화로 인해 기존의 기업가정신 이론으로 기업가들이 새로운 비즈니스 기회를 인식하고 기업가적 가치를 추구하는 일련의 과정을 이해하기에는 충분치 않으며, 기업가정신의 특성 및 효과에 대한 새로운 접근이 필요하다는 문제의식을 바탕으로 최근 디지털 경제 환경에서의 기업가정신을 조망하는 새로운 이론적 틀로서 '디지털 기업가정신'이라는 개념 및 관련 연구분야가 부상하고 있다. 본 연구에서는 국가 단위에서 디지털 기업가정신의 고용효과를 탐색적으로 파악하기 위하여 국제 기업가정신 관련 조사인 「글로벌 기업가정신 모니터(GEM)」 데이터를 활용한 상관 관계 분석을 실시하였다. 연구 결과, 기업가적 활동에 있어서의 디지털 기술 활용 의지, 창업 의지, 6인 이상의 고용창출 의지 등이 상호 간 긍정적인 관련성을 가지는 것으로 나타났다. 이는 디지털 기술에 기반한 창업 또는 기업가적 활동에 대한 의지가 일자리 창출과 긍정적인 관계를 가진다는 의미다. 해외 학자들을 중심으로 이루어지고 있는 디지털 기업가정신 연구는 기업가정신 및 창업 프로세스에 대한 디지털화의 영향이나 디지털 기술의 혁신 및 새로운 벤처의 탄생에 의해 창출된 기업가적 기회에 대한 논의가 주를 이루고 있는 데 반하여, 본 연구에서는 디지털 기업가정신에 의해 창출되는 성과에 대해 살펴본다는 점에서 차별성이 있다. 또한 국내에서 많이 다루지 않은 디지털 기업가정신 관련 연구를 수행하고 그 결과를 발표함으로써 동 분야에 대한 국내 학계의 관심을 촉진할 것으로 기대된다는 점에서도 학술적 의의가 있다.

• 한국HCI학회:학술대회논문집
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• 2009.02a
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• pp.1069-1074
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• 2009

Public displays are evolving from a one-way display to an interactive medium which contains dynamic transition of various media. This study focuses on the interaction between human and digital technology-based art on public display from a HCI point of view, while several viewpoints exist on interactive public displays. We present a new interaction model which suggests different interactions depending on the viewer's distance and direction so that public display could offer rich media experiences. We have also and built an installation art to examine the efficacy of our interaction model. As such, we introduced two methodologies from HCI to derive our final interaction model. First of all, we analyze previous distance-dependent interaction models for public display in terms of context analytic approach, and propose an effective model for human-digital art interaction. Second, we introduce the concept of aura in HCI as user analytic approach to redefine interaction depending on the viewer's direction of attention. Thus, this study aims to suggest a new interaction model based on the previous two analyses to improve interaction between human and digital technology-based art on public display.

• Applied Chemistry for Engineering
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• v.27 no.1
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• pp.92-100
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• 2016

Low-temperature conversion of nitrogen oxides using plasma-assisted hydrocarbon selective catalytic reduction of (HC-SCR) was investigated. Plasma was created in the catalyst-packed bed so that it could directly interact with the catalyst. The effect of the reaction temperature, the shape of catalyst, the concentration of n-heptane as a reducing agent, the oxygen content, the water vapor content and the energy density on $NO_x$ removal was examined. $NO_x$ conversion efficiencies achieved with the plasma-catalytic hybrid process at a temperature of $250^{\circ}C$ and an specific energy input (SIE) of $42J\;L^{-1}$ were 83% and 69% for one-dimensional Ag catalyst ($Ag\;(nanowire)/{\gamma}-Al_2O_3$) and spherical Ag catalyst ($Ag\;(sphere)/{\gamma}-Al_2O_3$), respectively, whereas that obtained with the catalyst-alone was considerably lower (about 30%) even with $Ag\;(nanowire)/{\gamma}-Al_2O_3$ under the same condition. The enhanced catalytic activity towards $NO_x$ conversion in the presence of plasma can be explained by the formation of more reactive $NO_2$ species and partially oxidized hydrocarbon intermediates from the oxidation of NO and n-heptane under plasma discharge. Increasing the SIE tended to improve $NO_x$ conversion efficiency, and so did the increase in the n-heptane concentration; however, a further increase in the n-heptane concentration beyond $C_1/NO_x$ ratio of 5 did not improve the $NO_x$ conversion efficiency any more. The increase in the humidity affected negatively the $NO_x$ conversion efficiency, resulting in lowering the $NO_x$ conversion efficiency at the higher water vapor content, because water molecules competed with $NO_x$ species for the same active site. The $NO_x$ conversion efficiency increased with increasing the oxygen content from 3 to 15%, in particular at low SIE values, because the formation of $NO_2$ and partially oxidized hydrocarbon intermediates was facilitated.

• Journal of The Korean Association For Science Education
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• v.20 no.3
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• pp.455-467
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• 2000

The purpose of this study was to investigate the characteristics of formative assessments practiced in middle school science teaching from a constructivist perspective. In order to examine the practices of formative assessments in science teaching, 7 science classes were observed and video-taped for each of 2 instructions. We also interviewed the teachers and 3 students per each class with semi-structured questions. The findings indicated that 3 types of formative assessments were generally used in science teaching; planned, interactive, and transitional from planned to interactive. Teachers tended to assess students' personal, social, and scientific developments through formative assessments. The assessment of scientific development was the most frequent pattern and was classified into the assessments of content, process, and context. However, formative assessments concerning content covered in class were dominant. The processes of formative assessments consisted of three interdependent stages; getting informations from students, judging their responses, and giving feedbacks to them. The types of questions and feedbacks used were also influenced by the extent of interactions between the teachers and the students.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.2
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• pp.98-112
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• 2018

Intentional aggressive driving (IAD) is a very dangerous driving behavior that threatens to attack the adjacent vehicles. Most existing studies have focused on the independent driving characteristics of attack drivers. However, the identification of interactions between the offender and the victim is necessary for the traffic safety analysis. This study established multi-agent driving simulation environments to systematically analyze vehicle interactions in terms of traffic safety. Time-to-collision (TTC) was adopted to quantify vehicle interactions in terms of traffic safety. In addition, a exponential decay function was further applied to compare the overall pattern of change in crash potentials when IAD events occurred. The outcome of this study would be useful in developing policy-making activities to enhance traffic safety by reducing dangerous driving events including intentional aggressive driving.