• 환경위생공학
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• 제11권3호
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• pp.29-35
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• 1996

Numerical solutions were obtained to the model equations for various parameters characterizing the pore structure, effective internal diffusion and the chemical reaction constant. The conversion was decreased with the cause of pore closure at the surface of reacting particles, reduction of porosity, surface area of reaction and effective diffusion coefficient in the solid with the progress of reaction. Total conversion was strongly depend on the local conversion at surface. According to the decreasing of impregnated concentration of the copper oxide and the increase of the flue gases concentration, total conversion was increased. And the conversion were affected by gas flow rate and pore size distribution of the reacting solid.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2002년도 정기총회 및 학술대회
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• pp.9-14
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• 2002

Direct-conversion receiver(DCR) architecture has superior advantages in size, cost, and power over superheterodyne receiver architectures. However, the use of direct-conversion receiver architecture has been limited due to the direct-current offset noise. The ac coupling, which is used to overcome the direct-current offset noise, causes an inter-symbol interference(ISI), whose effects can be effectively mitigated using an equalizer. In this paper, the performance of a direct-conversion receiver with ac coupling in the presence of direct-current offset is analyzed via computer simulation. The simulation result shows that by using decision feedback equalizer with LMS(Least Mean Square) algorithm, signal-to-noise ratio loss of the direct-conversion receiver compared to the idea receiver can be reduced to less than 1㏈ for corner frequencies as large as 10% of the symbol rate.

• 한국연소학회지
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• 제7권3호
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• pp.16-22
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• 2002

Combustion performance of an internally cycloned circulating fluidized bed for paper sludge was discussed through a series of batch type experiments. Operation parameters such as water content, feeding mass of sludge and secondary air injection rate were varied to find out the effect on the combustion performance, which was examined with carbon conversion rate and pollutant emission such as CO and NOx. A conventional solid fuel reaction was observed in the experiments of varying water content and feeding mass of the sludge, which is characterized with kinetic limited reaction zone, diffusion limited reaction zone and transition zone. Secondary air injection with swirl enhances the mixing of the gas phase as well as the solid phase, and improves combustion efficiency accompanied with higher carbon conversion rate and lower pollutant emission rate.

• Journal of Microbiology and Biotechnology
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• 제7권6호
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• pp.438-440
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• 1997

A continuous fermentation system employing immobilized cells of Zymomonas mobilis and Saccharomyces cerevisiae was studied for the mass production of ethanol. Ethanol production by cells immobilized with Ca-alginate was better than those by cells immobilized with K-carrageenan. Maximum ethanol production employing a continuous system by cells immobilized with Ca-alginate was 77.5 $g.l^{-1}h^{-1}$ at a dilution rate of 1.85 $h^{-1}$ with 82% conversion rate for Z. mobilis while that was 40.2 $g.l^{-1}h^{-1}$ at a dilution rate of 0.92 $h^{-1}$ with 85% conversion rate for S. cerevisiae. These results suggest that Ca-alginate is a better cell immobilization matrix than K-carrageenan and that immobilized cells of Z. mobilis are more efficient than S. cerevisiae for ethanol production.

• 한국위성정보통신학회논문지
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• 제9권4호
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• pp.13-15
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• 2014

10 GHz 이상의 주파수에서는 강우가 위성링크감쇠의 유력한 전달현상이다. 강우감쇠를 예측하기 위해서는 평균년의 0.01%를 초과하는 1분단위로 누적된 강우율이 필요하다. 대부분의 강우데이터는 60분 누적시간으로 측정되었기 때문에, 강우데이터를 다수의 누적시간으로부터 1분 누적시간으로 변환하는 연구가 많이 수행되었다. 이 논문은 새로운 변환 모델인 다중회기모형을 제안하며, 제안 방안은 기존 방안보다 우수한 성능을 보여 주었다.

• Journal of the Korean Data and Information Science Society
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• 제25권6호
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• pp.1361-1369
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• 2014

월세가격 동향을 살펴볼 수 있는 국가승인통계인 월세가격동향조사는 8개시도 (수도권 및 지방광역시)의 3,000개 월세표본에 대하여 매월 월세가격을 파악하여 지역별, 주택유형별, 규모별 월세가격지수 및 증감률, 그리고 월세이율을 공표하고 있다. 이 통계에서 제공되는 월세가격지수는 월세시장 동향을 파악하는데 매우 중요한 지표로서, 적절한 주택정책의 수립과 평가에 활용되고 있다. 월세가격지수는 보증금과 월세의 이원적인 가격자료를 전월세전환율을 이용하여 완전월세액이라는 하나의 가격자료로 환산하여 그 변화율을 측정함으로써 산정되는데, 적용되는 전월세전환율 종류에 따라 상이한 가격지수가 도출될 수 있다. 현재 적용되고 있는 전월세전환율 하에서는 임차인의 입장에서 월세부담이 상승했다 하다라도 전세금 수준이 더 많이 상승한 경우 전월세전환율이 낮아져서 결과적으로 월세가격지수가 하락하는 현상이 발생될 수 있다. 따라서 현행 월세가격지수의 변동률에 대한 해석에 유의할 필요가 있다. 본 논문에서는 월세가격지수의 변동률을 전월세전환율 변화에 기인한 부분과 그렇지 않은 부분을 구분하여 분석할 수 있는 틀을 제공하고자 한다. 이러한 방법을 통하여 현재와 같이 전세금이 급격하게 상승하는 시장에서 월세가격지수가 떨어지는 경우, 적용된 전월세전환율 효과에 기인하지 않는 실제 월세수준의 변동 흐름을 보다 정확하게 파악할 수 있다.

• 한국수소및신에너지학회논문집
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• 제33권6호
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• pp.786-794
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• 2022

Green ammonia is a promising renewable energy carrier. Green ammonia can be used in various energy conversion devices (e.g., engine, fuel cell, etc.). Ammonia has to be fed with hydrogen for start-up and failure protection of some energy conversion devices. Ammonia can be converted into hydrogen by decomposition and partial oxidation. Especially, partial oxidation has the advantages of fast start-up, thermally self-sustaining operation and compact size. In this paper, thermodynamics, start-up and operation characteristics of ammonia partial oxidation were investigated. O₂/NH₃ ratio, ammonia flow rate and catalyst volume were varied as operation parameters. In thermodynamic analysis, ammonia conversion was maximized in the O₂/NH₃ range from 0.10 to 0.15. Ammonia partial oxidation reactor was successfully started using 12 V glow plug. At 0.13 of O₂/HN₃ ratio and 10 LPM of ammonia flow rate, ammonia partial oxidation reactor showed 90% of ammonia conversion over commercial Ru catalyst. In addition, Increasing O₂/NH₃ ratio from 0.10 to 0.13 was more effective for high ammonia conversion than increasing catalyst volume at 0.10 of O₂/NH₃.

• Journal of Biosystems Engineering
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• 제24권5호
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• pp.425-430
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• 1999

Complex environmental control systems were developed, which control properly the pig's environment in windowless pig-housing based on the thermoregulatory behaviors of pigs and concentrations of noxious gases (CO2 and NH3). The this study was conducted to assess the performance of complex environmental control systems by raising weaned piglets and growing pigs under different seasonal conditions. Average daily gain of pigs in the experimental pig-housing was slightly higher than that of pigs in the conventional pig-housing. Average daily gain was not significantly different in winter and spring(P＞0.05), but was significantly different in summer(P＜0.05). Feed conversion rate of pigs in the experimental pig-housing was smaller than that of pigs in the conventional pig-housing. Feed conversion rate was not significantly different in environment for weaned piglets and growing pigs resulted in the improved daily gain, feed conversion rate, and carcass quality of the finishing pigs. These results showed that the performance of the complex environmental control systems in windowless pig-housing was excellent for weaned piglets and growing pigs.

• Journal of information and communication convergence engineering
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• 제9권2호
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• pp.201-206
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• 2011

FRUC (Frame Rate Up-Conversion) technique needs an effective frame interpolation algorithm using motion information between adjacent neighboring frames. In order to have good visual qualities in the interpolated frames, it is necessary to develop an effective detection and interpolation algorithms for occluded regions. For this aim, this paper proposes an effective occluded region detection algorithm through the adaptive forward and backward motion searches and also by introducing the minimum value of normalized cross-correlation coefficient (NCCC). That is, the proposed scheme looks for the location with the minimum sum of absolute differences (SAD) and this value is compared to that of the location with the maximum value of NCCC based on the statistics of those relations. And, these results are compared with the size of motion vector and then the proposed algorithm decides whether the given block is the occluded region or not. Furthermore, once the occluded regions are classified, then this paper proposes an adaptive interpolation algorithm for occluded regions, which still exist in the merged frame, by using the neighboring pixel information and the available data in the occluded block. Computer simulations show that the proposed algorithm can effectively classify the occluded region, compared to the conventional SAD-based method and the performance of the proposed interpolation algorithm has better PSNR than the conventional algorithms.

• 대한수의학회지
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• 제6권1호
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• pp.18-23
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• 1966

The protein-bound iodine-131, the concentration of iodine-131 in blood, and the excretion rate of I-131 through urine and feces were observed in nine Korean native goats, 3 months age, following administration of $3{\mu}C$ of I-131 per kg of body weight. No signiant differences were found due to sex and castration. 1. The average protein-bound iodine-131 conversion ratio of goats was 16.7% in 24 hours. In castrated group, the lowest proteinbound iodine-131 conversion ratio was observed. 2. The average concentration of iodine-131 in bleed, increased very rapidly by 2 hours(4.75%) and rapidly decreased within 6 hours(0.73%). 3. The average excretion rate of I-131 through urine was highest in 24 hours(19.00%) and decreased rapidly within 48 hours(5.32%). 4. The average excretion ration rate of I-131 though feces was highest in 24 hours(2.55%), and decreased slowly.