• Proceedings of the Korean Society of Propulsion Engineers Conference
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• v.y2005m4
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• pp.259-264
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• 2005

Measurements of heat release are very important for controling combustion instabilities, which are closely connected with combustion instabilities. $OH^{\ast}$ images were acquired through a ICCD in this study, which were in use as indicating index of the reacting region, global and local heat release rate in the lean premixed combustion. The objectives of this study are to see the effect of equivalence ratio on global heat release rate and local Rayleigh index distribution. The local Rayleigh index distribution was acquired by information from central section of flame. This information was from the line-of-sight images which were inverted by the Abel de-convolution. In each condition, the mean value of heat release increased exponentially with equivalence for a periodic time. Local Rayleigh index distribution cleary showed the region of amplifying or damping the combustion instability as the equivalence ratio increased. This could provide an insight on the region of combustion instability and the structure of flames on the equivalence ratio.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.304-309
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• 2008

기존의 태풍예측과 관련된 연구들은 전 지구적인 흐름이 직접적으로 계산되지 않은 중규모 기상모형이나 태풍모형들을 이용하여왔다. 하지만 최근 전 세계적으로 전구 규모의 모형들이 40km 이하의 고해상도 모형들이 개발되어 20km이하의 초고해상도 시물레이션이 가능해짐에 따라 지역적인 기상현상들을 전구모형을 통해서 재현해 내고 있다. 따라서 본 연구에서는 고해상도 전구모형을 이용하여 태풍 실험을 하고자 하며, 독일기상청에서 개발된 Icosahedral-hexagonal 격자체계의 GME전구 모형을 이용한 태풍모의 결과를 기상청 태풍 best track과 비교 분석 하였다. 실험에 사용된 모형 분해능은 연직 47layer (7 soil layer 포함), 수평 약 40km와 20km으로 구성되었다. 최근 3년($2005{\sim}2007$)간의 동아시아지역을 지나간 태풍을 대상으로 하였다. 태풍모의 시작시간은 각 TD(Tropical Depression)발생 24시간 전 자료를 이용하였으며, 각 태풍의 소멸 24시간 후까지 모의하였다. GME 모형을 이용한 태풍모의 결과에서 best track의 경우 모의 시작 후 약 168시간 forcast 결과가 매우 유사한 경로를 따라 진행해 가고 있으며, 태풍의 전향이 이루어지는 시각은 ${\pm}3$시간 내외의 오차를 보이고 있다. 태풍경로의 경우 40km 결과에 비해 20km 모의 결과가 best track에 더 가까운 결과를 보이고 있다. 중심기압변화의 경우 40km의 결과가 20km 결과에 비해 변화경향이 유사한 형태를 보이고 있으며, 20km 결과의 경우 중심기압의 변화가 다소 급하게 나타나는 경향을 보이는 특성을 가지고 있지만 40km결과에 비해 최저 중심기압이 더욱 뚜렷하게 나타나고 있으며 특히, MANYI case의 경우 관측값 930hPa보다 더 낮은 911.4hPa의 결과를 보이고 있다. 풍속의 경우도 중심기압변화와 유사한 결과를 보이고 있으나, 최대 풍속의 경우 40km 결과에 비해 20km결과가 관측과의 오차범위가 $2{\sim}3\;m/s$ 내외로 나타나고 있다. 그리고 GME모형의 경우 태풍(TD) 발생 약168시간 이전에 예측이 가능한 결과를 보인다. 이 연구의 결과는 다른 기상모형에서 태풍 강도가 약하게 모의되던 현상이 상당히 개선된 것을 알 수 있으며, 이는 20km 고해상도 GME 모형이 태풍예측모형으로 활용이 간능 할 것으로 사료 된다.

• Journal of Energy Engineering
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• v.14 no.1
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• pp.24-29
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• 2005

In order to evaluate the performance of fire-protection foams used to protect structures from heat and fire damages, the thermal characteristics of them are experimentally investigated. This research focuses on the destruction of a fire-fighting foam subjected to heat radiation. A simple repeatable test apparatus for fire-protection foams subjected to fire radiation is developed. It involves a foam generation equipment, a fire source for heat generation, repeatable test procedures, and data acquisition techniques. Results of the experimental procedure indicated that each thermocouple within the foam responded in a similar manner and gradually to a temperature of 115℃～20℃. At this point, each trace generally rises to a temperature of approximately 90℃. The temperature gradient in the foam as time passes increases with increasing the foam expansion ratio. In addition, it is found that the temperature gradient along the foam for depth decreases with increasing the foam expansion ratio.

• Fire Science and Engineering
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• v.29 no.6
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• pp.13-19
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• 2015

This study was performed to test the combustive properties of Pinus rigida specimens treated with phosphorus (P) and nitrogen (N) additives. Each Pinus rigida specimen was painted three times with 15 wt% P-N additive solutions at room temperature. After drying the treated specimens, the combustion properties were examined using a cone calorimeter (ISO 5660-1). The time to ignition (TTI) for the treated specimens was 90 to 148 s except for the specimen treated with PP/$4NH_4^+$, and the time to flameout (TF) was 556 to 633 s, which was longer than that of virgin plate. While the The specimens treated with P-N additives showed 12.5 to 43.4% higher mean heat release rate ($HRR_{mean}$) and 11.8 to 43.1% higher total heat release (THR) than virgin plate. The effective heat of combustion (EHC) was by 2.9 to 17.5% lower than that of virgin plate. It can thus be concluded that the combustion-retardation properties were partially improved compared to those of virgin plate.

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.1
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• pp.137-142
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• 1994

The present paper was carried out to investigate the inhibition of carcinogenic N-nitrosodimethylamine(NDMA) formation by Maillard reactiion products and nondialyzable melanoidins, obtiane dfrom the glucoseamino acids(Lys, Gly, Arg, His) model systems under different pH conditions(pH 1.2, 4.2 and 6.0). Maillard raction products and nondialyzable melanoidins, produced from the 4 model systems, had a inhibitory action of N-nitrosodimethylamine formation. The inhibitiondegree by the nondialyzable mealanoidins. at pH 1.2 was similar to that at pH 4.2 and that by ascorbic acid at pH 1.2 . Inhibitory action of N-nitrosodimehylamine formation by the reduced Maillard reaction products and nondialyzable melanoidins were lower than that of original samples. Accordingly, it is assumed that the inhibition of N-nitrosodimehtylamine formation of Maillard reaction products is due to their reducing powers.

• Solar Energy
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• v.12 no.3
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• pp.60-69
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• 1992

Heat transfer characteristics and heat storage rate for vertical cylinder packed with paraffin as a latent heat storage material were theoretically studied. Conduction and convection mechanism were applied to the solid and liquid phase, respectively, and the results were compared with that of pure conduction model. The effects of heating temperature, initial solid temperature and aspect ratio on rate of storage were also studied. In the initial stage of melting, the natural convection is nearly restricted by the friction at the wall and the phase boundary. But it is generated when about 40% of solid melts and again it shrinks by the hot liquid situated on the upper part of the cylinder. So overall melting rate is higher then that for pure conduction model. The increase in heating temperature and aspect ratio activates the natural convection, so melting rate becomes higher. And the larger the aspect ratio, the greater the difference between upper and lower size of the solid. In the initial stage of melting, the initial temperature of solid paraffin has great effect on the melting rate, but as melting proceeds its effect lessens gradually.

• The KIPS Transactions:PartB
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• v.17B no.1
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• pp.79-84
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• 2010

Matching spots between two sets of 2-dimensional electrophoresis can make it possible to find out the generation, extinction and change of proteins. Generally protein spots are separated by 2-dimensional electrophoresis. This process makes the position of the same protein spot a little different according to the status of the tissue or the experimental environment. Matching the spots shows that the relation of spots is non-uniform and non-linear transformation. However we can also find that the local relation preserves the topology. This study proposes a matching method motivated by the preservation of the topology. To compare the similarity of the topology, we compared the distance and the angle between neighbour spots. Experimental result shows that the proposed method is effective.

• KDI Journal of Economic Policy
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• v.17 no.1
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• pp.51-79
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• 1995

본 연구는 겸업은행(兼業銀行)과 전업은행(專業銀行)의 장단점에 대한 논의 중에서 충분히 취급되지 못한 문제라 볼 수 있는 은행(銀行)의 산업자본참여(産業資本參與)와 경제성장(經濟成長)간의 관계를 역사적으로 조명하고 이를 이론적인 모형과 실증분석을 통해 살펴본다. 역사적으로 보았을 때 겸업은행제도, 특히 그 제도의 핵심인 은행(銀行)의 산업(産業)에 대한 자본참여(資本參與)는 산업자금조달(産業資金調達)을 용이하게 만듦으로써 일찍이 산업혁명을 일으켰던 영국에 비해 후진국이었던 독일(獨逸)이나 일본(日本)을 선진국으로 발돋움하게 만들었던 중요한 금융혁신(金融革新)이다. 본 연구의 모형에서는 은행의 대출시장과 경쟁적으로 작용하는 잘 발달된 자본시장(資本市場)이 있기 전까지는 은행(銀行)에 의한 산업기업(産業企業)의 주식보유(株式保有)가 은행의 이익을 기업의 이익과 동일시 하도록 함으로써 기업의 투자(投資) 및 성장(成長)을 높인다는 것을 보인다. 그러나 모형(模型)의 이러한 효과는 자본시장이 발달하여 대출시장과 자본시장에서 기업이 자금조달에 무차별하게 되면 소멸된다. 한편 은행의 산업기업주식보유와 반대로 기업(企業)이 은행(銀行)의 주식(株式)을 보유할 수도 있는데, 본 모형에 따르면 이는 기업의 투자 및 성장에 영향을 미치지 못하는 것으로 나타난다. 이러한 결과를 실증분석을 통해 살펴보면 자본시장(資本市場)의 발달(發達)이 비교적 뒤떨어졌다고 판단되는 대륙형(大陸型) 금융제도를 갖고 있는 나라의 경우 은행의 기업주식보유는 성장에 정(正)의 효과를 주는 반면, 영미형(英美型) 금융제도를 갖고 있는 나라의 경우 이러한 효과는 발견되지 않는 것으로 나타나 모형의 결론을 지지한다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.2 no.4
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• pp.583-592
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• 1998

In this paper, the cell loss rate is analyzed in terms of the input traffic stream of different speed in ATM network. The cell loss rate is calculated by birth-death process of Leaky-Bucket mechanism as the representative algorithm of usage parameter control. The cell loss rate assumed 2-state MMPP input process to be birth-death process by considering the character of token pool about finite capacity queue. The results from numerical analysis show that the cell loss rate decreases abruptly according to the buffer size increase. The computer simulation by SIMSCRIPT II.5 has been done and compared with on/off input source case to verify the analysis results.

• Journal of Labour Economics
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• v.28 no.3
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• pp.111-139
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• 2005

This study analyzed employment instability, defining the increase of employment instability as 'a greater possibility of losing a job and a declining possibility of re-employment'. Flow variable measurements showed that the extent of employment instability was higher post 2000 compared to the period of before financial crisis. When considering the status of workers, such an increase in employment instability can be characterized by a greater possibility of unemployment for daily workers. If this is examined in conjunction with job creation and destruction, employment instability is increased not because there are less jobs being created but because there is an actual decline in the number of jobs and also because the jobs that are being created are mostly temporary. On the other hand the increased instability is due to the large-scaled public work policy under the financial crisis.