• 한국콘텐츠학회논문지
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• 제20권10호
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• pp.190-198
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• 2020

스마트폰 기술의 발전은 인간의 생활에 편리를 가져왔으나, 과도한 스마트폰 사용은 다양한 사고의 원인이 되기도 한다. 이 중 생명과 직결되는 대표적인 위험한 사고가 보행 중 부주의로 인한 안전사고이다. 본 연구에서는 보행 중 스마트폰을 사용할 때, 이러한 사고를 방지할 수 있도록 하는 애플리케이션 서비스 'Smombie Safe Go' UI(user interface)를 제안하고자 하였다. 이를 위해, 자료 조사와 사용자 관찰을 통해 보행자 여정맵을 작성하고 사용자 보행 중 안전에 필요한 주요 기능을 도출하였는데, 투명한 인터페이스를 비롯하여 장애물 위치 알림, 위험에 대한 주의와 경고 기능이 필요한 것으로 나타났다. 서비스 내용을 구체화하기 위하여 사용자 관찰을 통해 스마트폰을 사용하면서 보행 시에 맞닥뜨리는 위험상황을 세 가지로 - ① 전방에 장애물이 나타날 경우, ② 횡단보도에 신호등이 있는 경우, ③ 횡단보도에 신호등이 없는 경우- 구분하였다. 위험상황별 시나리오를 작성하고, 각 상황에서 위험을 경고하는 앱서비스 flow와 UI를 설계하였다. 또한 이 서비스 구현을 위해 V2N(Vehicle to Network), AI 3D 물체인식기술, 비콘(Beacon) 등의 기술들을 검토하고 활용방식을 제안하였다. 나아가 연구의 심화를 통해, 'Smombie Safe Go'는 일반 보행자 뿐 만 아니라, 시각 장애인들에게 안전한 보행을 지원할 수 있는 앱서비스로 활용이 가능할 것으로 예측된다.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2001년도 제22회 KOSCI SYMPOSIUM 논문집
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• pp.99-105
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• 2001

For the design of selective catalytic reactors of NOx by $NH_3$, engineering approach can be performed to determine the reactor shape, mixing device and $NH_3$ injection system. This study shows the optimization of guide vanes to improve the flow pattern near the catalyst layer of SCR in a untility boiler. By varying their spacings and shapes, flow performance of guide vanes was analyzed to achieve an uniform velocity distribution which increases the NOx convesion efficiency, and a flow direction normal to the layer which minimises the erosion by the dust in the flue gas. Including these results, experimental and numerical studies for the SCR design were discussed.

• International Journal of Contents
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• 제11권3호
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• pp.54-62
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• 2015

In this paper, we investigate the impacts of the following four influential factors on flow in digital reading: contents, platforms, motivations, and places. The contents factor was subdivided into "news articles" and "journal papers"; platforms is comprised of "mobile phones," "tablets," and "laptops"; motivations consists of "pleasure" and "assignments"; and "home," "on the go," and "out of home" are the subdivisions of the places factor. We conducted a questionnaire survey with the study's participants and the following results are shown: 1) The flow during the reading of news articles is influenced by motivations, whereas the flow during the reading of journal papers is influenced by platforms. 2) Regarding mobile phones, motivations significantly affected the flow, whereas content types significantly affected the flow for tablets; also, laptops provided the best flow and articles can be read on the platform regardless of motivations. 3) Reading for pleasure rather than for assignments positively influenced the flow for all of the platforms. 4) With respect to news articles, the places providing flow are different across platforms. However, for journal papers, the places out of home provided good flow. For tablets, the places for flow significantly depended on the content type, which is not the case for laptops.

• 한국연소학회지
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• 제11권1호
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• pp.1-10
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• 2006

Oil-fired power plant usually uses several burners and combustion air is supplied to each burner through the complicated duct which is called windbox. A windbox should be designed to supply combustion air to each burner uniformly but, due to the complicated duct shape, flow distribution in the windbox is unbalanced and non-uniform supplies of combustion air are induced by these unbalanced flows in the windbox. These flow patterns tend to make flame unstable, increase the formation of pollutants and lower the overall combustion efficiency. To prevent these disadvantages, flow patterns in the windbox should be investigated for the uniform flow distribution. In this study, computational simulation method was used to investigate the flow distribution in a windbox and measured the velocities at the exit of burners in a real windbox and model tests to compare with CFD results. The results show two significant flow patterns. One is that the flow rates of each burner are different from each other and this means that all burners operate in different conditions of air to fuel ratio. The other is that the flow distribution at the exit of each burner is not axi-symmetric although the burner shape is axi-symmetric. Additionally some modifications of windbox shape and installation of baffles were proposed to make the uniform flow in the windox.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2004년도 제28회 KOSCO SYMPOSIUM 논문집
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• pp.199-206
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• 2004

In the multi-burner power plant, uneven supplies of combustion air to multi-burner are induced by unbalanced flow distribution in the windbox. These flow patterns tend to make flame unstable, increase the formation of pollutants and lower the overall combustion efficiency. To prevent these disadvantages, flow patterns in the windbox should be investigated and made to be distributed uniformly, In this study, scaled windbox model was used for tests and measured the velocities at the exit of the each burner and compared those with the CFD results.

• 한국압력기기공학회 논문집
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• 제8권2호
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• pp.33-41
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• 2012

The component cooling water heat exchangers are critical components in a nuclear power plant. As the operation years of the heat exchanger go by, the maintenance costs required for continuous operation also increase. Most heat exchangers have carbon steel shells, tube support plates and flow baffles. The titanium tube is susceptible to flow induced vibration. The damage on carbon steel tube support rod and titanium tube around cooling water entrance area is inevitable. Therefore, analysis of internal flow around the component cooling water entrance and tube channel is a good opportunity to seek for failure prevention practice and maintenance method. The numerical study was carried out by FLUENT code to find out the causes of tube failure and its location.

• 마이크로전자및패키징학회지
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• 제26권3호
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• pp.81-88
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• 2019

본 연구에서는 그래핀 산화(graphene oxide, GO) 분말 첨가가 ball grid array(BGA) 패키지와 printed circuit board(PCB)간 Sn-3.0Ag-0.5Cu(SAC305) 무연솔더 접합부의 electromigration(EM) 수명에 미치는 영향에 대하여 보고 하였다. 솔더 접합 직후, Ni/Au표면처리된 패키지 접합계면에서는 $(Cu,Ni)_6Sn_5$가 생성되었으며 organic solderability preservative(OSP) 표면처리 된 PCB 접합계면에서는 $Cu_6Sn_5$ 금속간화합물(intermetallic compound, IMC)이 생성되었다. $130^{\circ}C$, $1.0{\times}10^3A/cm^2$ 전류밀도 하에서 EM 수명평가 결과, GO를 첨가하지 않은 솔더 접합부의 평균 파괴 시간은 189.9 hrs으로 도출되었고, GO를 첨가한 솔더 접합부의 평균 파괴 시간은 367.1 hrs으로 도출되었다. EM에 의한 손상은 패키지 접합계면에 비하여 pad 직경이 작은 PCB 접합계면에서 전자 유입에 의한 Cu의 소모로 인하여 발생하였다. 한편, 첨가된 GO는 하부계면의 $Cu_6Sn_5$ IMC와 솔더 사이에 분포하는 것을 확인하였다. 따라서, SAC305 무연솔더에 첨가된 GO가 전류 집중 영역에서 Cu의 빠른 확산을 억제하여 우수한 EM 신뢰성을 갖는 것으로 생각된다.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2006년도 제33회 KOSCO SYMPOSIUM 논문집
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• pp.137-144
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• 2006

Oil-fired power plants usually use several burners and the combustion air is supplied to each burner through the complicated duct which is called windbox. A windbox should be designed to supply combustion air to each burner evenly but, due to the complicated duct shape, flow distribution in the windbox is unbalanced and uneven supplies of combustion air to each burner are induced by these unbalanced flow distribution in the windbox. These flow patterns tend to make flame unstable, increase the formation of pollutants and lower the overall combustion efficiency. To prevent these disadvantages, flow patterns in the windbox should be investigated for the uniform flow distribution. In this study, computational simulation method was used to investigate the flow distribution in the windbox and measured the velocities at the exit of burners in the real windbox to compare with CFD results. The results show two significant flow patterns. One is that the flow rates of each burner are different from each other and this means that all burners operate in different conditions of air to fuel ratio. The other is that the flow distribution at the exit of each burner is not axi-symmetric although the burner shape is axi-symmetric and this increases the pollutant products like CO.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2005년도 제31회 KOSCO SYMPOSIUM 논문집
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• pp.85-92
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• 2005

Oil-fired power plants usually use several burners and the combustion air is supplied to each burner through the complicated duct which is called windbox. A windbox should be designed to supply combustion air to each burner evenly but, due to the complicated duct shape, flow distribution in the windbox is unbalanced and uneven supplies of combustion air to each burner are induced by these unbalanced flow distribution in the windbox. These flow patterns tend to make flame unstable, increase the formation of pollutants and lower the overall combustion efficiency. To prevent these disadvantages, flow patterns in the windbox should be investigated for the uniform flow distribution. In this study, computational simulation method was used to investigate the flow distribution in the windbox and measured the velocities at the exit of burners in the real windbox to compare with CFD results. The results show two significant flow patterns. One is that the flow rates of each burner are different from each other and this means that all burners operate in different conditions of air to fuel ratio. The other is that the flow distribution at the exit of each burner is not axi-symmetric although the burner shape is axi-symmetric and this increases the pollutant products like CO.

• Nuclear Engineering and Technology
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• 제34권5호
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• pp.502-516
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• 2002

Wolsong NPP are CANDU6 type reactors and there are 4 CANDU6 type reactors in commercial operation. CANDU type reactors require on-power refuelling by two remote controlled F/Ms (Fuelling Machines). Most of channels, fuel bundles are float by channel coolant flow and move toward downstream, however in about 30% of channels the coolant flow are not sufficient enough to carry fuel bundles to downstream. For those channels a special device, FARE (Flow Assist Ram Extension) device, is used to create additional force to push fuel bundles. It has been showing that during fuelling operation of some channels the channel coolant flow rate is reduced below specified limit (80% of normal), and consequently trip alarm signal turns on. This phenomenon occurs on selected channels that are instrumented for the channel flow and required to use the FARE device for refuelling. Hence it is believed that the FARE device causes the problem. It is also suspected that other channels that do not use the FARE device for refuelling might also go into channel flow low state. The analysis revealed that the channel How low occurs as the FARE device is introduced into the core and disappears as the FARE device is removed from the core. This paper presented the FARE device behavior, detailed fuelling operation sequence with the FARE device and effect on channel flow low phenomena. The FARE device components design changes are also suggested, such as increasing the number or now holes in the tube and flow slots in the ring orifice.