• 한국연소학회:학술대회논문집
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• 2003.12a
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• pp.57-61
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• 2003

In the combustion modeling of non-premixed flames, the mixture fraction conserved scalar approach is widely utilized because reactants are mixed at the molecular level before burning and atomic elements are conserved in chemical reactions. In the mixture fraction approach, combustion process is simplified to a mixing problem and the interaction between chemistry and turbulence could be modelled by many sophisticated combustion models including the flamelet model and CMC. However, most of the mixture fraction approach is restricted to one mixture system. In this study, the flamelet model based on the two-feed system is extended to the multiple fuel-feeding systems by the two mixture fraction conserved scalar approach.

• Journal of Energy Engineering
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• v.24 no.2
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• pp.17-21
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• 2015

Restriction orifices in the feed and bleed circuit of nuclear power plant are designed using computer program capable of handling multiple hole cascade orifice assembly. Single hole stages of orifice assembly are alternated with multihole stages where necessary. The distance between stages is such that it allows full pressure recovery. The minimum static pressure is higher than vapor pressure at the operating temperature so that cavitation does not occur. Piping sizes are reviewed and increased if necessary to improve rigidity.

• Journal of Korean Society of Water and Wastewater
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• v.29 no.1
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• pp.1-9
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• 2015

A combined treatment system using multiple source water is becoming important as an alternative to conventional water supply for small-scale water systems. In this research, combined water treatment systems were investigated for simultaneous use of multi-source water including rainwater, ground water, river water, and reclaimed wastewater. A laboratory-scale system was developed to systematically compare various combinations of water treatment processes, including sand filtration, microfiltration (MF), granular activated carbon (GAC), and nanofiltration (NF). Results showed that the efficiency of combined water treatment systems was affected by the quality of feed waters. In addition, a simply approach based on the concept of linear combination was suggested to support a decision-making for the optimum water treatment systems with the consideration of final water quality.

• Journal of Power Electronics
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• v.16 no.3
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• pp.1236-1243
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• 2016

This paper presents the analysis and design of an active electromagnetic interference (EMI) filter (AEF) for the common-mode (CM) noise reduction of switching power converters. The features of the several types of AEFs are discussed and compared in terms of implementation. The feed-forward AEF with a voltage-sensing and voltage-cancellation (VSVC) structure is implemented for an LLC resonant converter to replace a multiple-stage passive EMI filter and thereby reduce CM noise. The characteristics and performance of the VSVC-type AEF are investigated through theoretical and experimental works.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.1
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• pp.130-133
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• 2020

Smart pig farm which is based on IoT has been widely adopted by many pig farmers. In order to achieve optimal control of smart pig farm, the relation between environmental conditions and performance metric should be characterized. In this study, the relation between multiple environmental conditions including temperature, humidity and various performance metrics, which are daily gain, feed intake, and MSY, is analyzed based on data obtained from 55 real pig farm. Especially, based on preprocessing of data, various regression based machine learning algorithms are considered. Through performance evaluation, we show that the performance can be predicted with high precision, which can improve the efficiency of management.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.2
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• pp.253-260
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• 2018

The acoustic communication channel in shallow underwater is typically shown as time-varying multipath fading channel characteristics. The received signal through channel transmission cause inter-symbol interference (ISI) owing to multiple components of different time delay and amplitude. To compensate for this, several techniques have been used, and one of them is acoustic equalizer. In this study, we used four equalizers - feed forward equalizer (FFE), decision directed equalizer (DDE), decision feedback equalizer (DFE) and combination DDE with DFE to compensate ISI. And we applied two adaptive algorithms to adjust coefficient of equalizers - normalized least mean square algorithm and recursive least square algorithm. As result, we found that it has a significant performance improvement over 6 dB on SNR in nonlinear equalizer. By combination of DFE and DDE has almost best performance in any case.

• Korean Business Review
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• v.21 no.2
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• pp.171-194
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• 2008

In this study, specific review for the recent trend both in technical parts and the contents of IFE will be revealed. At the same time, how the passenger's satisfaction on IFE will lead to make an intention of repurchase and create the transmission of positive feed backs on the concerned airline has been thoroughly studied. In order to do the above, 250 air traveling passengers has participated the survey and 235 survey forms has been analyzed by Multiple Regression Analysis. According to the analysis, the physical environmental Improvement in aircraft system helps to Increase the satisfaction degree on IFE. The convenience is revealed as the most effective factor in the satisfaction degree on IFE while the atmosphere and design is regarded as the similarly Important factor. The contents of IFE are obviously affecting the satisfaction degree in positive side. Consequently, the customers' satisfaction on IFE positively affects to the repurchase intention especially to the transmission of the feed back.

• Journal of Advanced Navigation Technology
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• v.20 no.4
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• pp.352-360
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• 2016

In this paper, a novel multiple multicast feed-back scheme for improving multimedia multicast and broadcast system based on IEEE 802.11. The proposed scheme improves multicast PPDU delivery ratio of next generation wireless LAN by utilizing multicast feed-back information. By using the proposed scheme, regardless of its size of multicast group, an AP STA could collect transmission failure information by receiving simultaneous NAK frame. The proposed scheme shows large performance enhancement in broadcast or multicast system of Intelligent Transport System and Passenger Entertainment Service. According to the analysis results, the proposed scheme could enhance wireless LAN multicast and broadcast performance significantly.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.9
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• pp.1336-1342
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• 2005

The present research work was conducted to evaluate the beneficial effects as well as the safety aspects of lactobacilli as probiotic. Lactobacilli were isolated from poultry faecal samples, feed samples and from some known preparations procured from poultry feed manufacturers. L. acidophilus and L. sporogenes were tested for the antibacterial activity against four poultry pathogens viz. Escherichia coli, Salmonella spp., Proteus spp. and Pseudomonas aeruginosa. Cell free supernatant (CFS) of L. acidophilus exhibited significantly higher antibacterial activity against Salmonella spp. at original pH (4.50${\pm}$0.02). At the adjusted pH (6.50${\pm}$0.02) significantly higher antibacterial activity was recorded against indicator organism except for P. aeruginosa. Likewise, L. sporogenes exhibited similar antibacterial activity at original as well as adjusted pH except for E. coli. Antibacterial activity against E. coli was significantly higher at adjusted pH than at original pH of CFS. The competitive exclusion of E. coli by lactobacilli over the intestinal epithelial cells (IEC) was checked. L. acidophilus strain I, which was of poultry origin, exhibited maximum attachment over IEC as compared to other three strains of non-poultry origin viz. L. acidophilus strain II, L. sporogenes strain I and II. Overall, L. acidophilus exhibited higher competitive exclusion as compared to L. sporogenes. All the lactobacilli of poultry origin were most sensitive to penicillin G, amoxycillin, ampicillin and chloramphenicol, least sensitive to sulphamethizole, ciprofloxacin, neomycin, norfloxacin and pefloxacin and resistant to metronidazole and nalidixic acid. The isolates from probiotic preparations were most sensitive to ampicillin, amoxycillin and tetracycline, least sensitive to sulphamethizole, norfloxacin, neomycin and ceftriazone and resistant to nalidixic acid and metronidazole. Eight of the multiple drug resistant lactobacilli isolates were studied for the presence of plasmids. Plasmids could be extracted from six isolates of lactobacilli. These plasmids could be responsible for bacteriocin production or for antibiotic resistance of the strains. The lactobacilli need further studies regarding their safety for use in the probiotic preparations.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.12
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• pp.1708-1716
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• 2013

The objective of the trial was to study the relationship between the methane ($CH_4$) production and the Cornell Net Carbohydrate and Protein System (CNCPS) carbohydrate fractions of feeds for cattle and the suitability of CNCPS carbohydrate fractions as the dietary variables in modeling the $CH_4$ production in rumen fermentation. Forty-five rations for cattle with the concentrate/roughage ratios of 10:90, 20:80, 30:70, 40:60, and 50:50 were formulated as feed samples. The Menke and Steingass's gas test was used for the measurement of $CH_4$ production. The feed samples were incubated for 48 h and the $CH_4$ production was analyzed using gas chromatography. Statistical analysis indicated that the $CH_4$ production (mL) was closely correlated with the CNCPS carbohydrate fractions (g), i.e. CA (sugars); $CB_1$ (starch and pectin); $CB_2$ (available cell wall) in a multiple linear pattern: $CH_4=(89.16{\pm}14.93)$ $CA+(124.10{\pm}13.90)$ $CB_1+(30.58{\pm}11.72)$ $CB_2+(3.28{\pm}7.19)$, $R^2=0.81$, p<0.0001, n = 45. Validation of the model using 10 rations indicated that the $CH_4$ production of the rations for cattle could accurately be predicted based on the CNCPS carbohydrate fractions. The trial indicated that the CNCPS carbohydrate fractions CA, $CB_1$ and $CB_2$ were suitable dietary variables for predicting the $CH_4$ production in rumen fermentation in vitro.