• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.587-589
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• 2003

국내 전력 산업은 과거 수직통합적 독점구조에서 부문별 기능분할 및 경쟁도입을 점진적으로 추진하고 있으며 먼저 발전회사간 경쟁을 도입하기 위하여 한국전력의 발전부문을 6개의 발전회사로 분할 하였다. 2004년부터는 본격적으로 양방향 도매전력시장을 도입하여 운영할 계획에 있다. 도매전력시장의 도입으로 발생할 수 있는 가장 큰 시장 위험요소로는 시장가격의 수준 및 변동성에 대한 불확실성을 들 수 있다. 이는 시장참여자 모두에게 위험요소가 될 수 있으며 이를 위하여 정부주도하에 경쟁시장 이행기 동안의 과도기적 위험관리 도구를 제공하게 되며 발전회사와 판매회사 사이의 강제적 계약인 베스팅 계약이 포함될 것으로 예상된다. 여러가지의 베스팅 계약 중에서 Two-way 베스팅 계약은 발전회사와 판매회사와의 계약량, 계약가격을 정부 또는 관련기관에서 지정하는 것으로 이러한 Two-way 베스팅 계약은 도매전력시장의 초기에 발전회사의 손실을 최소화하는 역할을 할 것으로 예상되지만 반대로 수익을 제한하는 요소로도 작용할 수 있다. 따라서 본 연구에서는 베스팅 계약 중에서 Two-way 베스팅 계약에 대한 분석을 수행하고 이를 토대로 하여 베스팅 계약 하에서 발전회사의 수익을 최적화 할 수 있는 전략에 대한 연구를 수행하였다.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.6
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• pp.461-466
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• 2012

Recently, building energy systems with solar collector and solar module have increased to improve energy problem, a heat island, a global warming and carbon dioxide emissions. In this study, value of solar radiation in areas was analyzed using TRNSYS simulation, and the optimum tilt and orientation angle for installing a photovoltaic module was examined. Average values of the weather data in the past twenty years in areas were used as input data. The results show that the tilt angle of a photovoltaic module for gaining the annual maximum solar radiation varies in different localities, and values of the annual solar radiation gained by using the variable photovoltaic module increased by 2.5 percent as compared with that gained by using the fixed photovoltaic module. When fixed photovoltaic module is installed, it should be examined the tilt and orientation angle for installing a photovoltaic module was examined.

• Korean Journal of Soil Science and Fertilizer
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• v.36 no.4
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• pp.239-246
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• 2003

We examined the relationships among community composition, microbial population, and microbial biomass to determine whether different land use leads to differences in microbial community composition. And also the relationships between soil characteristics and microbial community composition were investigated. There was no difference in pH between uncultivated and cultivated soils, but electrical conductivity, and contents of organic matter, available P and exchangeable cations were greater in the cultivated soil compared to the uncultivated soil. A linear correlation ($r^2=0.557$, n=18, p<0.01) was found between biomass-C estimated with fumigation extraction technique and total amount of fatty acids. An increase of fatty acid methyl esters (FAMEs) for bacteria, actinomycetes, fungi and protozoa was observed in cultivated soil.

• Korean Journal of Soil Science and Fertilizer
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• v.29 no.2
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• pp.181-189
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• 1996

Several phosphate-solubilizing microorganisms were isolated in order to enhance the availability of insoluble phosphates accumulated in soils. Among the microorganisms, Aspergillus niger was selected and identified for this study. The phosphate-solubilizing activity. the phosphorus uptake by plants and the changes in soil microbial biomass by inoculation of Aspergillus niger were investigated. The uptake amounts of phosphorus by lettuce and pimiento were increased by inoculation of Aspergillus niger in all experimental treatments. There was negative correlation between the soil microbial biomass P and the soil phosphorus content. However the soil available phosphorus ($Y=-0.0007X^2+0.7126X^2-29.46$, $R=0.8283^{**}$) and the phosphorus absorption of plants ($Y=0.0049X^2-2.2352X+326.34$, $R=0.6350^*$) were significantly correlated to soil microbial biomass C on the positive section of quadric curve.

• Journal of Mushroom
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• v.12 no.3
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• pp.232-235
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• 2014

This study was carried out to investigated optimum mixing ratio of Korean natural Rhus verniciflua for production of functional oyster mushroom. Mycerial growth was some fast at addition of R. verniciflua sawdust, and not significant difference by increase of R. verniciflua substrate. Yields of fruiting body show the highest to 150.2 g/850 ml of medium which are addition 20% of R. verniciflua sawdust, and diameter of pileus and thick of stipes were the highest at addition 10% of R. verniciflua sawdust. The L value of stipes were the highest at addition 10% of R. verniciflua sawdust and the L value of pileus were decreased by increase of R. verniciflua substrate, but there was no significant difference in the a-value and the b-value.

• Korean Journal of Soil Science and Fertilizer
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• v.35 no.4
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• pp.243-252
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• 2002

To develop indicators for soil health evaluation, biological characteristics of native soils from the different parent materials were studied. Survival rate of fluorescent Pseudomonas in soils was the lowest as 0.1% while those of thermophilic Bacillus and alkaliphilic bacteria were over the 90% by the soil drying stress. There was positive relationship between soil microbial biomass and organic carbon exudated from the microbial biomass by the treatment. The average air-drying effect of soils was 39.7% with ranges of 9.7~95.0%. The propagules of mesophilic Bacillus and Gram negative bacteria were increased by the re-wetting of dried soils. Soil pH affected positively to the recovering rate of microbial number. Average recovering rate of microbes was 65.3%, and there was positive relationship between microbial biomass recovery and fluorescent Pseudomonas population.

• Journal of Mushroom
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• v.10 no.3
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• pp.129-135
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• 2012

This study was carried out to investigated optimum mixing ratio of Korean natural Cudrania tricuspidata for production of functional oyster mushroom. Total nitrogen and carbon source of Cudrania tricuspidata was 0.27% and 40.9%, respectively and C/N ratio was 152. Total nitrogen source and pH of substrates mixed with Cudrania tricuspidata were 2.7~2.8 and 4.9~5.1, respectively. The contents of $P_2O_5$, CaO, MgO and $Na_2O$ were no significant difference. Mycerial growth was faster at Cudrania tricuspidata 10% than that of control, but the other treatment was slower. Yields of fruiting body was the highest at Cudrania tricuspidata 20%, and diameter and thick of pileus were no significant difference to increase of Cudrania tricuspidata addition ratio. The L value of pileus was the highest at the Cudrania tricuspidata 20% during mushroom harvest, but there was no significant difference in the a-value and the b-value. Chemical contents of fruiting body were the highest at the Cudrania tricuspidata 30%.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.4
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• pp.257-265
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• 2009

The long-term effects of soil management history on microbial communities are still poorly understood. Our objectives were to determine the impact of long-term application of soil amendments on microbial communities in rice paddy fields. The treatments selected were control where crops were grown without any nutrient application (CON); nitrogen-phosphorus-potassium (NPK); NPK plus compost (CNPK); NPK plus lime (LNPK); and NPK plus silicate (WNPK). The long-term addition of organic and inorganic amendments significantly changed soil chemical properties. The amount of organic carbon increased in the treatments with fertilizer and amendments over that in the soil without inputs. However, we could not observe the differences of bacterial population among the treatments, but the number of aerobic bacteria increased by the addition of amendments. Isolates from the rice paddy soils before irrigation were Dactylosporangium, Ewingella, Geobacillus, Kocuria, Kurthia, Kytococcus, Lechevalieria, Micrococcus, Micromonospora, Paenibacillus, Pedobacter, Pseudomonas, Pseudoxanthomonas, Rhodococcus, Rothia, Sphingopyxis, Stenotrophomonas, and Variovorax. Dominant genera were Arthrobacter, Kocuria, Kurthia, and Bacillus in the long-term field. Microbial biomass was the highest in the compost treatment (CNPK), and was the lowest in the CON. Dehydrogenase activity in soils treated with rice compost straw was the highest and the activity showed an increasing trend according to treatment as follows: CON < WNPK < NPK = LNPK < CNPK. These results demonstrate that soil management practice, such as optimal application of fertilizer and amendment, that result in accumulations of organic carbon may increase microbial biomass and dehydrogenase activity in long-term rice paddy soils.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.10 no.1
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• pp.5-11
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• 1999

Background and Objectives : Recently, many people suffering from voice change visit otolaryngologist. So, it is important to study vocal function in patients with glottic or laryngeal disease. Aerodynamic investigation is valuable information about the efficiency of the larynx in translating air pressure to acoustic signal. The purpose of this study was to investigate the aerodynamic data in patients with vocal polyp, compare this data with that of the normal Korean. Materials and Methods : In aerodynamic study, maximum phonation time, mean air flow rate, phonatory flow volume and subglottal pressure were tested by using Aerophone II voice function analyzer in 157 normal korean and 143 patients with vocal polyp, aged from 20 to 69 years randomly selected. Results and Conclusion : In vocal polyp, maximum phonation time was significantly decreased and mean air How rate was increased. Phonatory flow volume was significantly decreased and subglottic pressure was increased only in female with vocal polyp. These data will be served as basic data of evaluation after treatment and postoperative assessment of the patients with vocal polyp.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.5
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• pp.231-237
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• 2017

This paper presents an implementation of a smart flowerpot which can adjust humidity and illumination automatically after monitoring the temperature, humidity, and illumination. We made a container of the flowerpot with a 3D printer and embedded a NodeMCU micro controller in it. We attached a temperature sensor, a humidity sensor, an illumination sensor, and a water pump to the NodeMCU. We developed a control program that adjusts humidity and illumination and ran it on the NodeMCU. Also we developed an Android application and set up an MQTT server. Using the MQTT server, the NodeMCU and the Android application can exchange messages which keep sensor values and commands. Using the Android application. the user can send the proper temperature, humidity, and illumination to the smart flowerpot and monitor the sensor values.