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Ammonia and Hydrogen Sulfide Removal from Swine House Exhaust Air Using a Dip Injection Wet Scrubber
Myeongcheol Shin,Seunghun Lee,Jisoo Wi,Heekwon Ahn 한국토양비료학회 2017 한국토양비료학회지 Vol.50 No.6
This study was conducted to evaluate the odor reduction efficacy of the dip injection wet scrubber (DIWS) using tap water as washing fluid. The NH₃ and H₂S removal efficiency of 7 day batch operated DIWS was evaluated twice over a total of 14 days of experiment. The NH3 removal efficiency ranged from 26 to 37%. The H₂S removal efficiency was between 22 and 30%. The pH of the washing fluid maintained below 8 and the NH₄<SUP>+</SUP> concentration tended to keep constant around 350 ppm after 5 days of washing-fluid replacement. Therefore, the 5-day washing fluid replacement interval is more preferable than the 7-day interval. The NH₄ <SUP>+</SUP> concentration and the electrical conductivity (EC) showed a high correlation. The EC measurement can be used as an alternative to conventional NH₄ <SUP>+</SUP> concentration measurement method for real time monitoring of washing fluid condition.
An Efficient Multimode Quantized Precoding Technique for MIMO Wireless Systems
Myeongcheol Shin,Sangheon Kim,Jiwon Kang,Lee, C. IEEE 2009 IEEE Transactions on Vehicular Technology VT Vol.58 No.2
<P>Multimode quantized precoding (QP) can provide full diversity gain or high capacity gain by adapting the number of substreams, as well as the precoding matrix, according to the instantaneous channel condition with low-rate feedback. Conventional multimode QP (MM-QP), however, does not consider the adaptive rate allocation among substreams; thus, it cannot have the additional gain by adaptive modulation. Furthermore, it is computationally complex since exhaustive matrix inversions are required to determine the optimal mode. In this paper, we propose an efficient MM-QP system that improves the performance of a conventional system in terms of error rate and has a lower computational complexity than the conventional system. First, we define the rate-partitioning vector as the mode and control the rate among substreams and the number of substreams according to the channel instantaneous condition. Second, to reduce the computational complexity for the receiver to determine the optimal mode, the simplified mode-selection technique using estimates of the modal metric is proposed. In the proposed mode-selection technique, the optimal mode can be obtained by several multiplication and division operations. Finally, the mode-reduction technique eliminating the less-frequently used modes is proposed, which leads to a significant reduction of the feedback information with negligible performance loss. In numerical experiments, it was verified that the proposed MM-QP system gives a better error-rate performance than the conventional system, with much less computational complexity for the same amount of feedback information.</P>
An Efficient Searching Algorithm for Receive Minimum Distance in MIMO Systems with ML Receiver
SHIN, Myeongcheol,KANG, Jiwon,YOO, Byungwook,LEE, Chungyong The Institute of Electronics, Information and Comm 2009 IEICE TRANSACTIONS ON COMMUNICATIONS - Vol.92 No.1
<P>A modified Schnorr-Euchner sphere decoding (SE-SD) algorithm to search for the receive minimum distance is presented. In the proposed algorithm, the visit to negative symmetric vectors of already spanned vectors is avoided by using a biased spanning, and the redundant processes to visit the all-zero vector are also eliminated. A numerical experiment shows that the modified SE-SD algorithm is much more efficient than the conventional algorithm in terms of average computational complexity.</P>
Ammonia and Hydrogen Sulfide Removal from Swine House Exhaust Air Using a Dip Injection Wet Scrubber
Shin, Myeongcheol,Lee, Seunghun,Wi, Jisoo,Ahn, Heekwon 한국토양비료학회 2017 한국토양비료학회지 Vol.50 No.6
This study was conducted to evaluate the odor reduction efficacy of the dip injection wet scrubber (DIWS) using tap water as washing fluid. The $NH_3$ and $H_2S$ removal efficiency of 7 day batch operated DIWS was evaluated twice over a total of 14 days of experiment. The $NH_3$ removal efficiency ranged from 26 to 37%. The $H_2S$ removal efficiency was between 22 and 30%. The pH of the washing fluid maintained below 8 and the $NH_4{^+}$ concentration tended to keep constant around 350 ppm after 5 days of washing-fluid replacement. Therefore, the 5-day washing fluid replacement interval is more preferable than the 7-day interval. The $NH_4{^+}$ concentration and the electrical conductivity (EC) showed a high correlation. The EC measurement can be used as an alternative to conventional $NH_4{^+}$ concentration measurement method for real time monitoring of washing fluid condition.
Effect of LSP in Phosphor-Converted WLEDs by Application of Ag NPs With/Without Silica Shell
Kim, Myeongcheol,Shin, Jeong Bin,Choi, Kyung Cheol IEEE 2016 Photonics Technology Letters Vol.28 No.17
<P>We report improved efficiency of a phosphor (Lu3Al5O12: Ce3+) by exploiting the plasmonic effect of silver nanoparticles (Ag NPs) for white light-emitting diodes (WLEDs). In a position close to the Ag NPs, the phosphor leads to higher quantum efficiency. Ag NPs are synthesized in various shapes for different spectral overlaps, and coated with a dielectric material to enhance the localized surface plasmon resonance. We present a new method that can improve the efficiency of WLEDs at appropriate concentrations of Ag NPs.</P>
Efficient Green Organic Light-Emitting Diodes by Plasmonic Silver Nanoparticles
Jeong Bin Shin,Se-Woong Baek,Seong Min Lee,Myeongcheol Kim,Jung-Yong Lee,Kyung Cheol Choi IEEE 2016 IEEE photonics technology letters Vol.28 No.3
<P>The resonance effect between the localized surface plasmon mode and the excited excitons in organic materials can enhance the optical and electrical performances of organic light-emitting diodes (OLEDs). Here, we show an enhancement in the luminescence efficiency of a green OLED by employing silver nanoparticles without an optical microcavity effect. The enhanced photoluminescence and exciton decay rate support the idea that the improved luminescence efficiency is due to the increased spontaneous emission rate of the emitter. Our results indicate that the plasmonic near-field interaction of the light-matter can be a strong engineering tool for high-efficiency organic optoelectronic devices in the display industry.</P>
An Efficient Code-Timing Acquisition for MIMO-CDMA Systems
Kwon, Yoonjoo,Shin, Myeongcheol,Kim, Kyung-Ho,Lee, Chungyong IEEE 2007 IEEE Transactions on Vehicular Technology VT Vol.56 No.5
<P> Two efficient algorithms are proposed for estimating code timing in a code-division multiple-access system in which multiple antennas are used at the transmitter and receiver. One of the algorithms is a pilot data transmission technique; while pilots in a conventional method are transmitted continuously, they are cyclically transmitted over each transmit antenna in the proposed algorithm. Hence, when compared to the conventional method, code allocation efficiency and more powerful transmission for unmodulated pilot channels could be achieved. The other is a weighted average (WA) method in which code-timing acquisition is achieved by averaging the estimated delays by weight. In addition, we propose two efficient code-timing estimators based on the proposed algorithms. Based on the analysis in this paper, the performance of the WA method is better than the equal-gain average method. Simulation results show that the two code-timing estimators based on the proposed methods provide a better code-timing acquisition performance than the conventional method. </P>
Plasmonically Enhanced Optical Characteristics From Europium Organometallic Complex
Jeong Bin Shin,Seong Min Lee,Myeongcheol Kim,Donghyuk Kim,Duk Young Jeon,Kyung Cheol Choi IEEE 2013 Photonics Technology Letters Vol.25 No.23
<P>We demonstrated that the plasmonic effect can enhance the photoluminescence of the europium organometallic complex in conventional organic light emitting diodes stack from an anode to emissive layer with solution processing. The aggregated gold nanoparticles (A-Au NPs) were incorporated in poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) layer to increase the luminescent quantum efficiency of the emissive layer. An enhancement of 31% was achieved in the emission intensity at 614 nm for samples with A-Au NPs. The reduced exciton lifetime measured by time-resolved photoluminescence comply with the Purcell effect. These improvements are attributed to the localized surface plasmon of A-Au NPs increasing the electric dipole transition rate from Eu<SUP>3+</SUP> ions.</P>
MIMO OFDM 시스템을 위한 향상된 채널 추정 기법
신명철,이학주,심세준,이충용,Shin Myeongcheol,Lee Hakju,Shim Seijoon,Lee Chungyong 대한전자공학회 2004 電子工學會論文誌-TC (Telecommunications) Vol.41 No.6
MIMO OFDM 시스템에서 comb형태의 훈련심볼을 사용하는 기존의 채널 추정방식은 가장자리 반송파 영역에서 채널 추정의 MSE(Mean Squared Error)가 큰 단점이 있다. 본 논문에서는 이러한 문제점을 해결하기 위해 순환구조를 갖는 comb형태 훈련심볼을 제안한다. 제안된 순환구조에서는 모든 종류의 comb 훈련심볼이 각 안테나로부터 순환 전송되며 수신 단에서는 각 comb 형태의 훈련심볼들을 이용해 채널을 추정한 후, MSE로부터 구해진 최적의 가중치를 곱함으로써 채널 주파수 응답을 추정한다 모의실험을 통해 제안된 방식이 기존의 comb 형태의 훈련심볼에 비해 높은 성능을 나타냄을 확인하였다. In MIMO-OFDM systems, conventional channel estimation techniques using comb type training symbols give relatively large mean squared errors(MSEs) at the edge subcarriers. To reduce the MSEs at these subcarriers, a cyclic comb type training structure is proposed. In the proposed cyclic training structure, all types of training symbols are transmitted cyclically at each antenna. At the receiver, the channel frequency responses that are estimated using each training symbol are averaged with weights obtained from the corresponding MSEs. Computer simulations showed that the proposed cyclic training structure gives more SNR gain than the conventional training structure.