• KIEAE Journal
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• 제13권5호
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• pp.89-96
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• 2013

Green roofs can reduce surface water runoff, provide a habitat for wildlife moderate the urban heat island effect, improve building insulation and energy efficiency, improve the air quality, create aesthetic and amenity value, and preserve the roof's waterproofing. Green roofs are mainly divided into three types : intensive, simple-intensive, and extensive. Especially, extensive roof environment is a harsh one for plant growth; limited water availability, wide temperature fluctuations, high exposure to wind and solar radiation create highly stressed environment. This study, aimed at extensive green roof, was carried out on the rooftop of the library at Seoul Women's Univ. from October to November, 2012 and from March to August, 2013. To suggest the most effective vegetation model for biodiversity and heat island mitigation, surface temperatures were monitored by each vegetation model. We found that herbaceous plants of Aster sphathulifolius, Aceriphyllum rossii and Belamcanda chinensis, shrub of Syringa patula 'Miss Kim', Thymus quinquecostatus var. japonica, Sedum species can mixing each other. Among them, the vegetation models including Sedum takesimense, Aster sphathulifolius, Thymus quinquecostatus var. japonica was more effective on the surface temperature mitigation, because the species have the tolerance and high ratio of covering, and also in water. Especially, in the treatment of bark mulching, they helped to increase the temperature of vegetation models. In the case of summer, temperature mitigation of vegetation models were no significant difference among vegetation types. Compared to surface temperature of June, July and August were apparent impact of temperature mitigation, it shows that temperature mitigation are strongly influenced by substrate water content.

• 설비공학논문집
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• 제28권10호
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• pp.402-407
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• 2016

Ground-coupled heat pump systems have been widely used, as they are regarded as a renewable energy source and ensure a high annual efficiency. Among the system components, borehole heat exchangers (BHE) play an important role in decreasing the entering water temperature (EWT) to heat pumps in the cooling season, and consequently improve the COP. The optimal sizing of the BHEs is crucial for a successful project. Other than the existing sizing methods, a simulation-based design tool is more applicable for modern complex geothermal systems, and it may also be useful since design and engineering works operate on the same platform. A simulation-based sizing method is proposed in this study using the well-known Duct STorage (DST) model in Trnsys. TRNOPT, the Trnsys optimization tool, is used to search for an optimal value of the length of BHEs under given ground loads and ground properties. The result shows that a maximum EWT of BHEs during a design period (10 years) successfully approaches the design EWT while providing an optimal BHE length. Compared to the existing design tool, very similar lengths are calculated by both methods with a small error of 1.07%.

• 설비공학논문집
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• 제20권12호
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• pp.802-807
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• 2008

A Study on Typical Rates of Water-use for School Facilities has been carried out in this work. Water supply system is given much weight in school facilities. Therefore, it set up a basis efficiency using of water sources to calculate typical rates of water use. The results are summarized as follows; 1) On the whole, typical rates of water-use was founded out 15 L/stu. d in pirmary school, 10 L/stu. d in middle school and 30 L/stu. d in high school smaller than the existing it. It was rate of water-use change as season and Max. Rates of water-use was July. 2) I deem that school hours are 5 hour's in primary school, 7 hour's in middle school and 8 hour's in high school. It the concept of 1 hour that is lesson time 40 minutes and resting time 10 minutes in primary school, lesson time 45 minutes and resting time 10 minutes in middle school and lesson time 50 minutes and resting time 10 minutes in high school. 3) It is desired that we calculate the volume of pump and water tank throughout this concept and the size of water tank should be 1.5 times with taking peak load into consideration by this study on typical rate of water-use. 4) The amount of using water increases in gradually and I consider the life cycle of facilities is more than 10 years. As a result, I can forecast that the size will be insufficiency but I deem that if we devise a plan about parallel pumping on water tank space, we can cope with it. Also, it is expected that we can cut back the transport energy by controlling pump volume.

• 융합정보논문지
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• 제8권2호
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• pp.233-238
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• 2018

중소기업 및 영세기업들은 생산관리 뿐만 아니라 설비, 안전, 에너지 관리 측면에서 중소기업의 운영 관리를 위해서 다양한 시도를 하고 있다. 그러나, 중소기업은 투자 여력이 없어 중소기업의 경영 개선과 생산성 향상을 위한 스마트팩토리 구축이 쉽지 않은 상황이다. 본 논문에서는 중소기업에서 현재 운영 중인 공장 장비를 부분적으로 연동하는 스마트팩토리를 구축 알고리즘을 제안한다. 제안 알고리즘은 중소기업의 스마트팩토리 환경을 단계적으로 구축하여 운영할 수 있도록 전체 제조 공정 중 제품 정보와 출시 정보를 IoT 장치에 이용하여 수집 보관 관리 처리 하도록 하고 있다. 또한, 제안 알고리즘은 장치간 인증 정보를 중앙의 서버가 중앙집중식으로 관리함으로써 IoT 장치 수에 상관없이 IoT간 연계를 자동화하는 특징이 있다. 성능평가 결과, 제안 알고리즘은 스마트팩토리 환경을 구축하기 전의 공장 프로세스와 효율성을 평가한 결과 13.7% 향상된 결과를 얻었고, 공장 내 제품 처리 시간도 19.8% 향상된 결과를 얻었다. 또한, 공정 프로세스에 투입된 인력 투입 비용도 37.1% 감소된 결과를 얻었다.

• KIEAE Journal
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• 제11권2호
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• pp.105-111
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• 2011

Aims of this study is to investigate the daylighting control strategy of venetian blind system was performed as a function of ratio of shading height to window and slat angles in the preliminary stage of the parametric study. Floor-to-ceiling window walls of living spaces are used widely in apartment buildings since the Korean government has legally allowed elimination of the balcony area. Enlarging living area by balcony elimination, the larger glass area of window is exposed to the direct sunlight. As a common sunlight controlling device, blind system can be used in all orientations and all latitudes and it may obstruct, absorb, reflect and transmit solar radiation to building by proper adjusting. However, blind system can produce discomfort in occupant and less energy efficiency, if it has not been controlled optimally. The simulation model was based on the unit module of typical living space with balcony elimination. The room dimension was $6.0m(w){\times}6.9m(d){\times}2.7m(h)$ with floor to ceiling height of 2.5m. The blind system was simulated at five slat angles (horizontal, $30^{\circ}$, $45^{\circ}$ upward and downward tilted) and the four ratio of shading height to window (fully closed, partly opened, no-blind) using the Desktop RADIANCE 2.0 program. The series of simulation results indicates that the advantages of available daylight and outside of view can be improved by proper adjusting blind system.

• 한국재료학회지
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• 제22권10호
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• pp.504-507
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• 2012

Synthesis of RGO (reduced graphene oxide)-CdS composite material was performed through CBD (chemical bath deposition) method in which graphene oxide served as the support and Cadmium Sulfate Hydrate as the starting material. Graphene-based semiconductor photocatalysts have attracted extensive attention due to their usefulness for environmental and energy applications. The band gap (2.4 eV) of CdS corresponds well with the spectrum of sunlight because the crystalline phase, size, morphology, specic surface area and defects, etc., of CdS can affect its photocatalytic activity. The specific surface structure (morphology) of the photocatalyst can be effective for the suppression of recombination between photogenerated electrons and holes. Graphene (GN) has unique properties such as a high value of Young's modulus, large theoretical specific surface area, excellent thermal conductivity, high mobility of charge carriers, and good optical transmittance. These excellent properties make GN an ideal building block in nanocomposites. It can act as an excellent electron-acceptor/transport material. Therefore, the morphology, structural characterization and crystal structure were observed using various analytical tools, such as X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and Raman spectroscopy. From this analysis, it is shown that CdS particles were well dispersed uniformly in the RGO sheet. Furthermore, the photocatalytic property of the resulting RGO-CdS composite is also discussed in relation to environmental applications such as the photocatalytic degradation of pollutants. It was found that the prepared RGO-CdS nanocomposites exhibited enhanced photocatalytic activity as compared with that of CdS nanoparticles. Therefore, better efficiency of photodegradation was found for water purification applications using RGO-CdS composite.

• 한국인터넷방송통신학회논문지
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• 제21권6호
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• pp.91-97
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• 2021

마이크로서버는 컴퓨팅 서버의 일종으로 2개 이상의 CPU 소켓을 별도의 컴퓨팅 보드에 구현하고, 다수 개의 컴퓨팅 보드를 메인 보드에 집적하는 형태를 지닌다. 클러스터 시스템을 구축하는데 있어서, 마이크로서버를 사용하면 기존의 서버를 여러 대 랙에 장착하는 방법에 비해, 에너지 효율, 상면, 관리 용이성 측면에서 이점이 있다. 또한, 마이크로서버는 컴퓨팅 보드내 CPU 소켓들, 혹은 컴퓨팅 보드끼리 별도의 내부 연결망을 사용할 수 있어서 성능 측면에서도 이점이 존재한다. 본 논문에서 제안된 마이크로서버는 4개의 CPU 소켓을 지닌 컴퓨팅 보드를 메인보드에 총 16개 장착할 수 있는 서버로 Serial-RapidIO (SRIO)를 내부 연결망으로 사용한다. 마이크로서버의 핵심 성능 이슈인 내부 연결망 측면에서의 성능 비교 분석을 위해, 상용 마이크로서버와 내부 연결망 성능을 비교하고 정량화한다. 시험 결과, 내부 연결망을 활용한 데이터 전송 시 대역폭 측면에서 최대 7배 높은 성능을 보였다. 아울러, 실제 클라우드 컴퓨팅에 사용되는 벤치마크 프로그램 적용 시험에서도 유사 CPU 성능 마이크로서버 대비 60%의 수행시간 감소 효과를 얻었다.

• Nuclear Engineering and Technology
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• 제53권10호
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• pp.3344-3351
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• 2021

The Rare Isotope Science Project was launched in 2011 in Korea toward constructing the Rare isotope Accelerator complex for ON line experiments (RAON). RAON will house several experimental systems, including the Muon Spin Rotation/Relaxation/Resonance (μSR) facility in High Energy Experimental Building B. This facility will use 600-MeV protons with a maximum current of 660 pμA and beam power of 400 kW. The key μSR features will facilitate projects related to condensed-matter and nuclear physics. Typical experiments require a few million surface muons fully spin-polarized opposite to their momentum for application to small samples. Here, we describe the design of a muon transport beam line for delivering the requisite muon numbers and the electromagnetic-component specifications in the μSR facility. We determine the beam-line configuration via beam-optics calculations and the transmission efficiency via single-particle tracking simulations. The electromagnet properties, including fringe field effects, are applied for each component in the calculations. The designed surface-muon beamline is 17.3 m long, consisting of 2 solenoids, 2 dipoles affording 70° deflection, 9 quadrupoles, and a Wien filter to eliminate contaminant positrons. The average incident-muon flux and spin rotation angle are estimated as 5.2 × 10⁶ μ⁺/s and 45°, respectively.

• 융합정보논문지
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• 제9권1호
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• pp.116-122
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• 2019

최근 중소기업은 세계적인 경쟁력을 갖추기 위해서 공정/품질/에너지 데이터 집계가 자동 또는 실시간으로 처리할 수 있는 산업 구조로 급격하게 변화하고 있다. 특히, 중소기업 생산 공정에서 생산되는 실시간 정보 분석은 중소기업의 유의미한 성과들을 분석, 예측, 처방 및 이행하는 새로운 공정 프로세스 형태로 진화해 가고 있다. 본 논문에서는 중소기업에서 생상되는 데이터를 고도화할 수 있도록 중소기업의 자동화 생산 정보 시스템을 빅데이터화 할 수 있는 플랫폼 구축 모델을 제안한다. 제안 모델은 스마트한 중소기업의 데이터 수집을 위해 중소기업에서 생산되는 제품의 기본 정보에 대한 다양한 데이터를 활용해 중소기업의 운영 효율화(컨설팅 및 교육 등) 및 전략적 의사결정을 지원할 수 있는 기능이 있다. 또한, 제안 모델은 종소기업의 정보 공유 및 시스템 연계가 원활하게 서로 다른 지역적 특성 및 분야를 가지는 중소기업들간에 긴밀한 협조가 가능한 것이 특징이다.

• 한국정보통신학회논문지
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• 제24권9호
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• pp.1158-1164
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• 2020

국내의 경우 수입 에너지에 대한 의존도가 매우 높아 낭비되는 전력을 저하시키고 전력 효율성을 향상시키기 위해 저전력 기술인 Zigbee를 기반으로 대기전력 저감 연구가 이루어지고 있다. 그러나 Zigbee는 IoT 표준 프로토콜이 아니고, 네트워크 기반이 아니기 때문에 별도의 게이트웨이를 두어 네트워크를 구축해야 하며, 국제적으로 제시하고 있는 기기 전력 소비량에 대한 기준도 모호하기 때문에 대기전력에 대한 연구는 미흡한 상태이다. 따라서 본 논문에서는 기존 Zigbee 기술에 IoT 표준 프로토콜인 MQTT를 적용하여 별도의 게이트웨이 없이 네트워크망을 구축하고, 대기전력 저하 및 사용자의 패턴을 수집하는 대기전력 저감 시스템을 설계 및 구현하였다. 기존 시스템과 평가한 결과 기존 시스템 대비 약 7.11%의 대기전력이 소모된 것을 확인하였다.