• 대한기계학회논문집A
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• 제32권12호
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• pp.1102-1106
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• 2008

Microfluidics deals with the behavior, precise control and manipulation of fluids at a micro scale. It has become increasingly prevalent in various applications such as biomedical applications (diagnostics, therapeutics, and cell/tissue engineering), inkjet head, and fuel cells etc. The issue of inspection and characterization of microfluidics has emerged as a major consideration in design, fabrication, and detection of microfluidic devices. In this paper, we characterize a diffusion based mixing in Y-microchannel using a fluorescent optical scanner based on a DVD pick-up module, which is widely used in optical storages. Using fluorescent dye, we measure the fluorescent intensity that represents the mixing patterns in Y-microchannel. We also compare these experimental results with computational fluid dynamics (CFD) simulation ones. It is shown that the proposed optical scanner can be used as an alternative measurement system with high performance and cost-effectiveness, compared to conventional optical tools such as epifluorescent microscopes using high resolution CCD camera and confocal microscopes with photomultiplier (PMT) detectors.

• 한국콘텐츠학회논문지
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• 제2권4호
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• pp.67-75
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• 2002

최근 지식기반사회에 접어들면서 정보의 양은 폭발적으로 증가하고 있으며, 인터넷과 디지털 컨텐츠의 확산으로 인해 정보의 접근성 또한 매우 향상되었다. 이로 인해 세계적으로 방대한 정보의 체계적인 관리와 효율적인 분석이 큰 이슈가 되고 있다. 또한, 정보의 패러다임이 정보의 접근시대에서 정보의 분석시대로 전환되고 있으며, 이에 대비하여 기술정보를 통한 기술트렌드의 분석과 이를 시스템적으로 구현하는 방법의 정립이 시급한 실정이다. 따라서, 본 연구에서는 기술정보 DB의 검색결과를 온라인상에서 시스템적으로 신속하게 분석함으로써 연구개발 및 기술개발의 방향설정에 기여하며 정보수집 및 분석에 소요되는 노력과 시간을 획기적으로 단축시킬 수 있는 정보분석시스템을 개발하였다.

• 상하수도학회지
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• 제30권4호
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• pp.417-425
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• 2016

Desalination is a key technology to overcome water shortage problem in a near future. High energy consumption is an Achilles' heel in desalination technology. Osmotically driven membrane processes like forward osmosis(FO) was introduced to address this energy issue. Characterizing membrane properties such as water permeability(A), salt permeability(B), and the resistance to salt diffusion within the support layer($K_{ICP}$) are very important to predict the performance of scaled-up FO processes. Currently, most of researches reported that the water permeability of FO membrane was measured by reverse osmosis(RO) type test. Permeating direction of RO and FO are different and RO test needs hydraulic pressure so that several problems can be occurred(i.e. membrane deformation, compaction and effect of concentration polarization). This study focuses on measuring water permeability of FO membrane by FO type test results in various experimental conditions. A statistical approach was developed to evaluate the three FO membrane properties(A, B, and $K_{ICP}$) and it predicted test result by the internal and external concentration polarization model.

• 한국환경과학회지
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• 제19권7호
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• pp.901-905
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• 2010

Emissions of leachate, odor, and landfill gas(LFG) from an open-dumping landfill site do harm to public health by contaminating neighboring soil, underground water, and rivers. Particularly, methane($CH_4$) and carbon dioxide($CO_2$), the main components of LFG, are especially noted as the causing material of the global warming that become seriously recognized worldwide issue. As one of alternatives in managing LFG, incineration of inflammable wastes that are generated during excavation process at an open-dumping landfill has been evaluated. Standard on stabilization for evaluation, neither $CH_4$ density nor $CO_2$ density could not Because meet 'less than 5%' criterion and so it is right to install a gas collection system during landfill renewal to prevent diffusion of odor and collect it. Because it shows considerable heating value, incineration of inflammable wastes might be the reasonable solution from the result of our study.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.277-279
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• 2005

The imbalance of energy demand and supply caused by rapid industrialization around the world and the associated environmental issues require and alternative energy source with possible renewable fuels. Political instability and depletion of cruel oils are other factors that cause fluctuation of oil price. Securing a new alternative energy source for the next century became an urgent issue that our nation is confronting with. As a matter of fact, the fuel cell technology can be widely used as next generation energy regardless of regions and climate. Specially, the ability of expansion and quick installation enable one to apply it for distributed power, where the technology is already gaining remarkable attentions for the application. Particularly, leading industrialized nations are focusing on the PEM fuel dell with anticipation that this technology will find their place of applications in the vehicles and homes. In this study, demonstrate the multi physics modeling of a proton exchange membrane(PEM) fuel cell with interdigitated flow field design. The model uses current balances, mass balance(Maxwell-Stefan diffusion for reactant, water and nitrogen gas) and momentum balance(gas flow) to simulate the PEM fuel cell behavior.

• International Journal of Advanced Culture Technology
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• 제8권2호
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• pp.146-158
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• 2020

As one of the successful brand activism ad campaigns in recent years, the current study focuses on the Always #LikeAGirl campaign that took on the issue of girls and female empowerment. As a viral video marketing campaign with YouTube as their main vehicle for campaign dissemination, this study examined how Always brand activism campaigns spread on YouTube by conducting a network analysis of YouTube video networks generated by the #LikeAGirl campaign spanning across five campaign periods. Quantifiable data (i.e., views, comments, likes, dislikes, user-generated videos) and structural network patterns show that the Always #LikeAGirl campaign was successful by both standards. Although the follow-up campaign periods were not as successful as the initial campaign, the substantial amount of views, comments, likes, and user-generated content showed that the consecutive campaigns still had impact. As shown through the network patterns, the main campaign ads were central in the diffusion of the campaign during the earlier periods but that role was passed onto the user-generated contents in the later periods. Implications of the findings and future social network analysis studies in brand advertising and brand activism campaigns are further discussed.

• 정보화정책
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• 제20권3호
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• pp.43-62
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• 2013

이 연구는 공공부문 스마트워크센터 사용자에 대한 AHP 설문을 이용하여 정책의 지속적 사용 및 확산을 위한 우선 정책 과제를 도출하고, 분석결과를 토대로 대응 방안을 모색하는 것을 목적으로 한다. AHP 설문을 위한 정책과제의 대분류는 기술 인프라 개선, 제도 개선, 인식 개선의 세 가지로 구성하였다. 기술 인프라는 스마트워크 기술개선과 스마트 워크 시설개선으로, 제도 개선은 법제도 개선과 추진체계 개선으로, 인식개선은 조직문화 개선과 사용자 인식개선으로 각각 중분류하였다. 총 12개의 정책과제 중 조직문화 개선이 중요성과 긴급성 측면에서 가장 우선적인 정책과제로 분석되었으며, 인사복무규정 개선, 정책결정자의 리더십, 사용자의 인식 개선 과제 등이 우선적으로 해소되어야 할 것으로 나타났다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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• pp.945-948
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• 2006

Chloride penetration into concrete is a hot issue of concern all over the world, notwithstanding, very few attempts have been conducted to explore the effect of cracks on choride penetration. Cracks provoke to lose a main function of watertightness of concrete and lead to reduce the service life of concrete. For this reason, it is necessary to define a critical crack width to prevent a quick chloride penetration through crack. In this study, experiment is focused on establishing a critical crack width in terms of chloride penetration. Concrete specimens with different crack widths I crack lengths have been subjected to rapid chloride migration testing. In a side of analytical solution, a simple approach to quantify the chloride diffusion coefficient of only crack zone excluding sound concrete was proposed. The result clearly showed a critical crack width of 0.03 mm. Based on the experimental results, a phenomenological model was proposed to explain the meaning of critical crack width in practical engineering. In this model, cracked concrete zone was divided into three zones. These zones corresponded to a wide crack, a zone with micro-cracks and an uncracked zone.

• 한국위성정보통신학회논문지
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• 제12권2호
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• pp.71-78
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• 2017

망 중립성은 ISP가 이용자에게 비차별성, 상호접속성, 접근성을 보장하여 누구든지 통제나 간섭 없이 동등한 서비스를 받을 수 있도록 하는 개념이다. 그러나 현재 인터넷 망은 P2P 서비스 확산과 실시간 대용량 비디오 스트리밍 서비스와 같이 버퍼링에 민감한 서비스에서 트래픽이 급증하고 있다. 이를 관리하기 위해 ISP가 서비스를 간섭, 변경, 통제하는 등 망 중립성을 훼손하면서, 망 중립성에 대한 논쟁이 끊임없이 발생하고 있다. 따라서 본 논문에서는 망 중립성의 원칙과 개념, 이에 대한 국내외의 입법 정책현황을 비교 분석하고, 이를 기반으로 국내 망 중립성 가이드라인의 쟁점사항과 개선방안을 제시한다.

• Nuclear Engineering and Technology
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• 제49권6호
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• pp.1157-1164
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• 2017

The Monte Carlo criticality simulation of decoupled systems, as for instance in large reactor cores, has been a challenging issue for a long time. In particular, due to limited computer time resources, the number of neutrons simulated per generation is still many order of magnitudes below realistic statistics, even during the start-up phases of reactors. This limited number of neutrons triggers a strong clustering effect of the neutron population that affects Monte Carlo tallies. Below a certain threshold, not only is the variance affected but also the estimation of the eigenvectors. In this paper we will build a time-dependent diffusion equation that takes into account both spatial correlations and population control (fixed number of neutrons along generations). We will show that its solution obeys a traveling wave dynamic, and we will discuss the mechanism that explains this biasing of local tallies whenever leakage boundary conditions are applied to the system.