• Journal of the Korean Data and Information Science Society
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• v.28 no.2
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• pp.395-406
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• 2017

The purpose of this study is to identify the pattern of daily electricity demand through clustering and classification. The hourly data was collected by KPS (Korea Power Exchange) between 2008 and 2012. The time trend was eliminated for conducting the pattern of daily electricity demand because electricity demand data is times series data. We have considered k-means clustering, Gaussian mixture model clustering, and functional clustering in order to find the optimal clustering method. The classification analysis was conducted to understand the relationship between external factors, day of the week, holiday, and weather. Data was divided into training data and test data. Training data consisted of external factors and clustered number between 2008 and 2011. Test data was daily data of external factors in 2012. Decision tree, random forest, Support vector machine, and Naive Bayes were used. As a result, Gaussian model based clustering and random forest showed the best prediction performance when the number of cluster was 8.

• Journal of Energy Engineering
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• v.26 no.3
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• pp.97-104
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• 2017

In this study, waste tire rubbers were pyrolyzed in a lab-scale pyrolysis plant equipped with a fluidized bed reactor in a temperature ranges of $450-650^{\circ}C$. The main object of this work is to investigate the properties of pyrolysis oil with reaction temperatures and the behavior of sulfur in the products when waste polypropylene was added for co-pyrolysis. The maximum yield of oil was about 52wt.% at the reaction temperature of $456^{\circ}C$. From GC-MS analysis, the pyrolysis oils consisted mainly of limonene, toluene, xylene, styrene, trimethylbenzene, methylnaphthalenes and some heteroatom(sulfur and nitrogen)-containing compounds. The addition of waste polypropylene resulted in decrease in sulfur contents of the pyrolysis oils.

• The Journal of the Korea Contents Association
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• v.12 no.12
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• pp.304-312
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• 2012

In this study, for behavior clinical signs and blood tests when autumn sudden fevered disease, Tsutsugamushi Disease is Single infected with mixing hemorrhagic fever with renal syndrom.221 positive patients, who have antibody titer more than 1:80 in serologic examination of Tsutsugamushi Disease in a general hospital, Jeollanam-do province, were adopted as a Analysis. in respect of frequency. Single infection patients of Tsutsugamushi Disease were 183 and mixed infection patients with Hemorrhagic Fever with Renal Syndrome were 38. In respect of age, patients over the 70's were mostly infected. In respect of sex, male patients were 70(31.7%) and female patients were 151(66.8%) Women were more infected than men. In respect of outbreak time, the more than 70% disease occurrence of all was charged in October and November and it also occurred in spring. In the clinical signs, fever(p=0.028), urtication(p=0.000) and muscle pain(p=0.000) of mixed infection was more higher than single infection. And in the blood tests, AST(p=0.000), ALT(p=0.000), blood urea nitrogen(p=0.002), total bilirubin(p=0.000) value of mixed infection was more higher than single infection.

• Magazine of the Korea Concrete Institute
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• v.10 no.5
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• pp.177-187
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• 1998

최근 국내에서 해양 구조물, 장대 교량의 하부구조물, LNG저장탱크 등 매스콘크리트의 증가추세에 따라 구조물의 고내구성과 관련하여 시멘트의수화열에 의한 온도균열의 발생을 최소화 시킬 수 있는 3성분계 혼합형 저발열시멘트가 개발되어 실 구조물의 적용단계에 있으나, 저발열시멘트가 개발되어 실 구조물의 적용단계에 있으나 저발열시멘트의 특성에 대한 전반적인 연구보고가 국내에서는 미진한 실정이다. 따라서 본 연구에서는 3성분계 혼합형 저발열시멘트의 특성 및 코\ulcorner리트의기초물성을 1종 보통포틀랜트 시멘트, 5종 내황산염시멘트, 슬래그시멘트와 비교하였다. 글 결과 저발열 콘크리트의 찹축강도는 초기재령에서 강도발현률이 적은 반면 장기강도발현률은 상당히 큰 경향을 보였다. 또한 수화열은 1종시멘트를 사용한 콘크리트에 비하여 1/3~1/2정도로 매스콘크리트의 수화열을 대폭적으로 저감시킬 수 있을 뿐만 아니라 염소이온에 대한 저항성이 상대적으로 높게 나타나 거대 해양 구조물의 적용에 매우 유리한 시멘트로 판단되었다.

• Korean Journal of Food Science and Technology
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• v.23 no.4
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• pp.465-470
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• 1991

In order to investigate the thermal and oxidative stability of different frying oils including soybean oil, palm oil, two blended oils of soybean-palm (5 : 5 and 7 : 3) and shortening, physico-chemical properties such as acid value, peroxide value, TBA value, degree of coloring, refractive index and specific gravity of the frying oils were measured during the preparation of French fried potatoes by repeated frying. The instability of soybean oil against thermal and oxidative degradation could be lessened by using blended oils in which the ratio of palm oil to soybean oil is more than 50%.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2001.05a
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• pp.45-52
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• 2001

The study on the heat exchanger with catalytic combustion was performed as the development of the catalytic combustion applications. This study tried to achieve the both goals-the mixture preheating and the heat transfer to working fluid simultaneously by using the steady state catalytic combustion. The combustion characteristics were investigated with the quantitative, qualitative experimental variants of the mixture. In addition, the temperature distribution of catalytic layer was investigated to investigate the correlation between the combustion characteristics and the heat balance of the catalytic layer. As a result, the steady state reaction within the appropriate range of temperature is the critical factor in catalytic applications. To get this, the sensible control of both the mixture flow and the heat balance of catalytic layer were required.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.453-456
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• 2011

An experimental investigation of the heat transfer characteristics of stretched premixed flames using Synthetic gas has been performed. Hydrogen and carbon mon-oxide which could be extracted from coal gasification process are the main fuel of synthetic-gas. Heat flux at the stagnation point was increased as global strainrate was increased, then the heat flux was decreased when a global strainrate reached a sudden point. Heat flux at the stagnation point is also affected by nozzle to impingement distance. Heat flux was increased as nozzle to impingement place distance was increased. This study is a foundation study of practical use of secondary gases from coals.

• Journal of Korea Foresty Energy
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• v.21 no.2
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• pp.62-68
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• 2002

Adiabatic property of plywood wall panel was examined to evaluate their thermal conductivities. The amount of heat loss was investigated through overall heat transmission experiment. Styroform and grass wool showed less heat loss. However, yellowsoil board and laminated lumber showed high volume specific heat capacity. When the changes of indoor and outdoor temperature were checked in model house, wall manufactured with styroform and grass wool was affected easily by the changes of outdoor temperature. Yellowsoil, the mixed board of yellowsoil and sawdust, and laminated lumber, which have high volume specific heat capacity, were not affected much. The rates of overall heat transmission were much better in styroform and grasswool, but the adiabatic properties were much higher in yellowsoil board and the mixed board of yellowsoil and sawdust. The results showed that the insulating material can be developed using yellowsoil and wood, which are nature friendly materials.

• Journal of Energy Engineering
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• v.23 no.4
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• pp.223-229
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• 2014

This study investigated the explosion characteristics of HCNG fuel using a simulation tool. The damage caused by the storage container explosion and vapor cloud explosion in a gas station was predicted. In case of an vapor cloud explosion in the HCNG station, 50~200kPa explosion pressure was predicted inside the station. When the cylinder explosion was occurred, in case of hydrogen, the measured influential distance of overpressure was 59m and radiant heat was 75m. In case of CNG, influential distance of overpressure was 89m and radiant heat was 144m would be estimated. In case of 30% HCNG that was blended with hydrogen and CNG, influential distance of overpressure was 81m and radiant heat was 130m were measured. The damage distance that explosive overpressure and radiant heat influenced CNG was seen as the highest. HCNG that was placed between CNG and hydrogen tended to be seen as more similar with CNG.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.7
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• pp.1465-1472
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• 2009

The effect of heat loss rate on NOx formation of $CH_4/air$premixed flame were examined numerically in a perfectly stirred reactor. The following conclusions were drawn. Under the adiabatic wall condition, an increase in the residence time causes a remarkable increases in NOx emission. Under the heat loss conditions, however, NOx decreases significantly as the heat transfer coefficient and residence time increase. As the heat loss rate increases, Thermal NO mechanism and Re-burning NO mechanism play an important role in the NOx reduction, but Prompt NO mechanism and $N_2O$-intermediate NO mechanism lead to the increase in NOx production. Although the NOx formation is actually related to complex NOx mechanism with the changes in the heat transfer coefficient and residence time, it was found that NOx concentration can be represented by independent Thermal NO mechanism. From these results, new NOx correlation combined with the heat loss rate and residence time was suggested for predicting the NOx concentration in a practical $CH_4/air$premixed combustor.