• Journal of environmental and Sanitary engineering
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• v.11 no.3
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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.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2002.11a
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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.

• Journal of the Korean Society of Combustion
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• v.7 no.3
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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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• v.7 no.6
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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.

• Journal of Satellite, Information and Communications
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• v.9 no.4
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• pp.13-15
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• 2014

At frequencies above 10 GHz, rain is a dominant propagation phenomenon on satellite link attenuation. The prediction of rain attenuation is based on the point rainfall rate for 0.01 % of an average year with one minute integration time. Most of available rain data have been measured with 60 minutes integration time, and many researchers have been studying on converting the rainfall rate data from various integration times to one minute integration time. This paper proposes a new Multiple Regression model for the conversion, and the proposed schemes show better performance than the existing schemes.

• Journal of the Korean Data and Information Science Society
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• v.25 no.6
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• pp.1361-1369
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• 2014

This research is for analyzing the change rate of housing rent price index produced by KAB (Korea Appraisal Board) in the monthly periodical, Survey on Housing Monthly Rent. The index is a very important and useful indicator to understand and diagnose the house rental market. However, the index is criticized in that it tends to decline when the price level of Jeonse (i.e., a typical type of dwellings in Korea, generally leased on a deposit basis for 1 or 2 years) is highly going up, which is inconsistent with the actual economic sentiment of tenants. We verify the reason why such phenomenon occurs and suggest a simple but novel method to analyze properly the change rate of the index. The main findings are as follows. The key factor to trigger the problem is the use of the conversion rate for Jeonse-to-monthly rent for constructing the rent price indexes. We separate the effect of the conversion rate out of the change rate of the index and quantify the adjusted real change rate showing an increase of the rent price level which is masked by the conversion rate before.

• Journal of Hydrogen and New Energy
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• v.33 no.6
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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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• v.24 no.5
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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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• v.9 no.2
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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.

• Korean Journal of Veterinary Research
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• v.6 no.1
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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.