• 한국수소및신에너지학회논문집
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• 제20권5호
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• pp.384-389
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• 2009

KEPRI (Korea Electric Power Research Institute) has studied planar type solid oxide fuel cell (SOFC) stacks using anode-supported cells and kW class co-generation systems for residential power generation. In this work, a 1 kW SOFC system consisted of a hot box part, a cold BOP (balance of plant) part, and a hot water reservoir. The hot box part contained a SOFC stack made up of 48 cells, a fuel reformer, a catalytic combustor, and heat exchangers. Thermal management and insulation system were especially designed for self-sustainable operation in that system. A cold BOP part was composed of blowers, pumps, a water trap, and system control units. When the 1 kW SOFC stack was tested using hydrogen at $750^{\circ}C$, the stack power was about $1.2\;kW_e$ at 30 A and $1.6\;kW_e$ at 50 A. Turning off an electric furnace, the SOFC system was operated using hydrogen and city gas without any external heat source. Under self-sustainable operation conditions, the stack power was about $1.3\;kW_e$ with hydrogen and $1.2\;kW_e$ with city gas respectively. The system also recuperated heat of about $1.1\;kW_{th}$ by making hot water.

• 한국전자파학회논문지
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• 제27권8호
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• pp.725-734
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• 2016

5세대 이동통신 시스템에서 스펙트럼 효율을 향상시키기 위한 새로운 후보 변조기술들이 제안되고 있다. 후보 변조기술로 다중반송파 기반의 UFMC(Universal Filtered Multi-Carrier), FBMC(Filter Bank Multi-Carrier)가 큰 주목을 받고 있으며, 최근 저복잡도 처리가 가능한 W(Weighted)-OFDM(Orthogonal Frequency Division Multiplexing) 시스템 또한 주목받고 있다. 본 논문에서는 기본적인 OFDM 시스템과 함께 UFMC, FBMC, W-OFDM 시스템에 HPA(High Power Amplifier) 비선형 특성이 고려되었을 경우, 각 시스템의 스펙트럼 특성과 BER(Bit Error Rate) 특성을 종합적으로 평가하여 보다 유력한 시스템을 찾는다. 시뮬레이션 결과로, 동일한 비선형 HPA 환경에서는 UFMC, FBMC, W-OFDM 시스템이 모두 유사한 스펙트럼 특성과 BER 특성을 보이는 것을 확인할 수 있다. 이러한 이유로 비선형 HPA 환경에서는 시간영역에서 저복잡도의 Windowing 처리만을 요구하는 W-OFDM 시스템이 다른 시스템에 비하여 유리함을 확인할 수 있다.

• International Journal of Naval Architecture and Ocean Engineering
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• 제3권2호
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• pp.150-158
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• 2011

Present study aims to investigate the influence of relative breakwater width W/L (W=width of breakwater, L=wavelength), wave steepness $H_i/gT^2$ (Hi=incident wave height, T=wave period) and relative wave height d/W (d=water depth) on forces in the moorings of horizontal interlaced multi-layered moored floating pipe breakwater (HIMMFPB) model. Studies were conducted on scaled down physical models having three layers of Poly Vinyl Chloride (PVC) pipes, wave steepness $H_i/gT^2$ varying from 0.063 to 0.849, relative width W/L varying from 0.4 to 2.65 and relative spacing S/D=2 (S=horizontal centre-to-centre spacing of pipes, D=diameter of pipes). Peak mooring forces were also measured and data collected is analyzed by plotting non-dimensional graphs depicting variation of $f_s/{\gamma}W^2$ ($f_s$=Sea side Mooring force, ${\gamma}$=specific weight of water) & $f_l/{\gamma}W^2$ ($f_l$=Lee side Mooring force) with $H_i/gT^2$ for d/W varying from 0.082 to 0.276 and also variation of $f_s/{\gamma}W^2$ and $f_l/{\gamma}W^2$ with W/L for $H_i$/d varying from 0.06 to 0.400.

• 한국세라믹학회지
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• 제45권12호
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• pp.772-776
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• 2008

The Korea Electric Power Research Institute (KEPRI) has been developing planar solid oxide fuel cells (SOFCs) and power systems for combined heat and power (CHP) units. The R&D work includes solid oxide fuel cell (SOFC) materials investigation, design and fabrication of single cells and stacks, and kW class SOFC CHP system development. Anode supported cells composed of Ni-YSZ/FL/YSZ/LSCF were enlarged up to $15{\times}15\;cm^2$ and stacks were manufactured using $10{\times}10\;cm^2$ cells and metallic interconnects such as ferritic stainless steel. The first-generation system had a 37-cell stack and an autothermal reformer for use with city gas. The system showed maximum stack power of about $1.3\;kW_{e,DC}$ and was able to recover heat of $0.57{\sim}1.2\;kW_{th}$ depending on loaded current by making hot water. The second-generation system was composed of an improved 48-cell stack and a prereformer (or steam reformer). The thermal management subsystem design including heat exchangers and insulators was also improved. The second-generation system was successfully operated without any external heat source. Under self-sustainable operation conditions, the stack power was about $1.3\;kW_{e,DC}$ with hydrogen and $1.2\;kW_{e,DC}$ with city. The system also recuperated heat of about $1.1\;kW_{th}$ by making hot water. Recently KEPRI manufactured a 2kW class SOFC stack and a system by scaling up the second-generation 1kW system and will develop a 5kW class CHP system by 2010.

• 한국실내디자인학회논문집
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• 제41호
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• pp.104-111
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• 2003

Most residential buildings in Korea are preferred to have maximum interior spaces, rather than consider its original design, overall building performance, and any other aspects since early 1990's. Especially in high-rise apartment buildings, balcony has been merged to living room to get more interior spaces and this renovation trends have been producing deep and narrow shapes of living rooms that was not initially intended by architects. On the other hand, the same gross area of each unit does not necessarily mean same width and depth ratio of each residential unit. Generally, we can categorize it to the deep or wide unit based on its width and depth ratio. Under these circumstances, this study analyzes the room usage pattern changes based on the space width and depth ratio and the effect of expansion of room space to the balcony. This study also includes about 180 apartments plan case studies to find out the relationships among w/d ratio changes, furniture arrangement types, and room configurations. In this research, general apartment room w/d ratios are 0.97 ∼ 1.23; 0.7(south facing sitting room), 1.23(south facing bed room), and 0.95(north facing bedroom). But, after expanding room space to balcony w/d ratio increased as follows; sitting room become 1.31, general south facing bedroom become 1.23, and north facing bedroom become 1.45. In addition to user preference of w/d ratio, many people prefer rectangular room shape a little(w/d ratio is 0.9 or 1.2) than square style (w/d ratio is 1.0) or very deep room style (w/d ratio Is more over 1.5). Accordingly, expanding the room space to balcony may make unsatisfactory room w/d ratio. Expanding room space to balcony should be considered by existing room w/d ratio.

• 한국산학기술학회논문지
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• 제19권6호
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• pp.628-633
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• 2018

GNSS의 정확도는 사용되는 장비에서부터 자료처리에 이르기까지 여러 가지 요인에 의해 그 정확도가 달라진다. 이것은 GNSS에 의한 위치결정이 요구되는 정확도에 따라 다르게 활용될 수 있기 때문이다. 높은 정확도를 요구하는 기준점 측량의 경우는 상대측위 방식으로 측량을 수행하게 되며, 기준점의 등급에 따라 관측시간과 자료처리 s/w가 다르게 사용되고 있다. 그러나 학술용 s/w는 사용자의 숙련도에 따라 그 정확도가 크게 좌우될 수 있어 기선거리가 짧은 경우에는 상업용 s/w를 사용하는 것이 효율성 측면에선 더 나을 수도 있다. 이에 본 연구에서는 GNSS측량 데이터에 대해 학술용 s/w와 상업용 s/w를 이용 자료처리를 수행 그 결과를 비교하였다. 연구 결과 수평위치에서는 2cm 미만의 차이를 나타냈으며, 높이 성과에 있어서는 5cm 미만의 차이를 나타냈다. 이러한 차이는 통합기준점 측량 규정에서 명시하고 있는 오차 범위에 존재하는 것으로 나타났다. 이상의 결과를 토대로 장기선이 아닌 중단기선에서는 상업용 s/w를 활용하여 GNSS 자료처리에 사용할 수 있다는 것을 입증할 수 있었다.

• Asian-Australasian Journal of Animal Sciences
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• 제33권4호
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• pp.662-669
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• 2020

Objective: This study was conducted to evaluate the effect of red glasswort (RG) (Salicornia herbacea L.) curing on the physicochemical, textural and sensory properties of cooked pork loin ham (M. longissimus thoracis et lumborum). Methods: All treatments were cured with different salt and RG powder levels. RG0 treatment was prepared with only 4% NaCl (w/w) as a control, and RG25, 3% NaCl:1% RG (w/w); RG50, 2% NaCl:2% RG (w/w); RG75, 1% NaCl:3% RG (w/w); RG100, 0% NaCl:4% RG (w/w) treatments were prepared sequentially. All samples were individually vacuum packaged in polyethylene bags and stored for 7 d at 3℃±1℃. Results: The results showed that as the rate of RG substitution increased, pH value, redness, myofibrillar protein solubility, and myofibrillar fragmentation index increased (p<0.05), but salt concentration and shear force decreased (p<0.05). However, there were no significant differences in cooking loss and moisture content. In terms of sensory evaluation, RG100 exhibited higher scores in tenderness and juiciness than RG0 (p<0.05). Conclusion: The partial substitution of NaCl by RG could improve the physicochemical properties, textural and sensory characteristics of cooked pork loin. Therefore, it is suggested that RG as a natural salt replacer could be an effective ingredient for developing low-sodium cured hams.

• 한국초등수학교육학회지
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• 제2권1호
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• pp.61-80
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• 1998

원격 교육에 관한 연구는 교육 공학의 일반적 관점에서 볼 때 비교적 활발히 이루어지고 있는 편이지만, 수학 교육과 관련해서는 관련 연구를 찾아보기 어렵다, 열린 교육과 관련하여 원격 교육은 기본적으로 ① 원거리 교실 모델, ② front-end 체제 설계의 두 가지 수업 유형을 고려할 수 있으며, 여기에 새로운 원격 교육 모델로서 ③ 지식 구축 모델, ④ 자료에 기초한 교육모델로 나누어 볼 수 있다. 원격 수학 학습 시스템의 구성 요소는 크게 나누어 S/W, C/W와 H/W로 구분할 수 있다. 원격 교육 시스템이 보다 높은 질의 수학 교수-학습의 효과를 거두게 하기 위하여서는 기본적인 강의를 보조하는 text는 물론 graphics, animation, video, audio 등의 복합적인 다중모드(multimode)의 정보 매체로 표현된 자료를 제공하는 multimedia를 활용하는 H/W와 S/W가 절대적으로 필요하다. 원격 교육 시스템에 멀티미디어를 적용한 실제 예를 들어보면 MIPOS, SDS의 원격 교육 시스템, 내촌 초등학교의 원격 교육 시스템, 두레 멀티미디어 응용 개발 플랫폼 등을 들 수 있다.

• 한국연초학회지
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• 제17권2호
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• pp.177-183
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• 1995

This study was conducted to develop the most precise NIR(near infrared spectrometric) calibration for rapid determination of chemical composition in ground samples of toasted burley tobacco using stepwise, stepup, principal component regression(PCR), partial least square(PLS) and modified partial least square(MPLS) calibration method. The number of wavelength(W) selected by stepup multiple linear regression using: second derivative spectra was as follows: total sugar(TS)-4 W, nicotine-9 W, total nitrogen(TN)-2 W, ash-8 W, total volatile base(TVB)-5 W, chlorine4 W, L of color-6 W, a of color-6 W and b of color-7 W. Comparing the calibration equations followed by each chemical components, the most precise calibration equation was MPLS for 75, a and b of color, PLS for nicotine, ash, TVB, chlorine and L of color and stepup for TN. The standard error of calibration(SEC) and standard error of performance(SEP) between result of near infrared analysis and standard laboratory analysis were 0.18, 0.40% for 75, 0.06, 0.08% for nicotine, 0.18, 0.16% for TN, 0.33, 0.46% for ash, 0.04, 0.03% for TVB, 0.08, 0.06% for chlorine, 0.54, 0.58 for L of color, 0.22, 0.22 for a of color and 0.27, 0.27 for b of color, respectively. The SEC and SEP of ash and TVB were within allowable error of standard laboratory analysis, nicotine, TN and chlorine were 1.2-2.0 times and 75 were 2.1-4.0 times larger than allowable error of standard laboratory analysis. The ratio of SEC and SEP to mean were 1.5, 1.6% for L of color, 3.7, 3.8% for a of color and 1.8, 1.8% for b of color, respectively. Key words : burley tobacco chemistry, near infrared spectroscopy.

• 생명과학회지
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• 제29권12호
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• pp.1345-1350
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• 2019

한약재로 쓰이는 용담(Gentiana scabra)의 열수 추출물(GS-W)을 정상 마우스에 경구 투여할 경우 in vivo 위장관이송률(ITR)이 유의적이고 용량 의존적으로 증가한다는 사실이, 최근 본 연구진에 의해 보고된 바 있다. 이에 본 연구에서는, in vivo 실험적 위장관 운동 기능 저해(GMD) 마우스 모델에서는 GS-W가 ITR에 어떠한 영향을 미치는지 검정하고자 하였다. GS-W는 5 g/kg의 고용량 경구 투여 시에도 정상 마우스에서 급성 독성을 나타내지 않았고, GMD 마우스에서 ITR을 유의적이고 용량 의존적으로 증가시켰으며, 특히 1 g/kg 경구 투여 시의 ITR은 cisapride 투여 시보다 수치 상으로 높았다. 이러한 결과들은, 1990년대까지 임상적으로 널리 처방되었으나 치명적인 부작용으로 인해 2000년 이후 시장에서 철수된 약물인 cisapride를 GS-W가 대체하여, 인간의 다양한 GMD 상황을 예방하거나 그 증상을 완화시킬 수 있는 잠재력이 있음을 시사한다.