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Replication and Pathogenesis of the Pandemic (H1N1) 2009 Influenza Virus in Mammalian Models
권동혁,Kyeongcheol Shin,Seungtae Kim,하윤철,Jang-Hoon Choi,Jeong Seon Yang,Joo-Yeon Lee,채찬희,Hee-Bok Oh,Chun Kang 한국미생물학회 2010 The journal of microbiology Vol.48 No.5
This study aimed to characterize the replication and pathogenic properties of a Korean pandemic (H1N1) 2009 influenza virus isolate in ferrets and mice. Ferrets infected with A/Korea/01/2009 (H1N1) virus showed mild clinical signs. The virus replicated well in lungs and slightly in brains with no replication in any other organs. Severe bronchopneumonia and thickening of alveolar walls were detected in the lungs. Viral antigens were detected in the bronchiolar epithelial cells, in peribronchial glands with severe peribronchitis and in cells present in the alveoli. A/Korea/01/2009 (H1N1) virus-infected mice showed weight loss and pathological lung lesions including perivascular cuffing, interstitial pneumonia and alveolitis. The virus replicated highly in the lungs and slightly in the nasal tissues. Viral antigens were detected in bronchiolar epithelial cells, pneumocytes and interstitial macrophages. However, seasonal H1N1 influenza virus did not replicate in the lungs of ferrets, and viral antigens were not detected. Thus, this Korean pandemic (H1N1) 2009 isolate infected the lungs of ferrets and mice successfully and caused more pathological lesions than did the seasonal influenza virus.
Dong-Min Shin,Hansul Cho,Kyeongcheol Yang IEEE 2012 IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY Vol.61 No.2
<P>The symbol error rate (SER) and bit error rate (BER) of the multiple-input-multiple-output (MIMO) system with decision-feedback detection (DFD) are analyzed over a Rayleigh fading channel. By using the concepts of “event” and “state” related to error propagation due to the decision-feedback process, we present general closed-form expressions for the SER and BER of each layer over quadrature-amplitude modulation (QAM) or phase-shift keying (PSK) for an arbitrary number of transmit and receive antennas. We also derive the asymptotic BER and SER performances of each layer. Numerical results show that our analysis matches very well with the Monte Carlo simulation. Our approach can be extended to the exact performance analysis of various wireless communication systems.</P>
Mapping Selection and Code Construction for 2^m-ary Polar-Coded Modulation
Dong-Min Shin,Seung-Chan Lim,Kyeongcheol Yang IEEE 2012 IEEE communications letters Vol.16 No.6
<P>This paper proposes a mapping strategy and a code construction method for 2<SUP>m</SUP>-ary polar-coded modulation. In order to find a good mapping for a polar code in an efficient way, we reduce a search space for mapping patterns by exploiting the properties of its polarizing matrix. Once a mapping is selected, the set of unfrozen information bits to define a polar code is automatically determined. Numerical results show that our approach can provide a performance gain of about 0.3-0.5 dB over a conventional approach using random mapping and the polar code optimized for binary phase-shift keying (BPSK) modulation, when pulse-amplitude modulation (PAM) with Gray labelling is employed.</P>
Dong-Min Shin,Kyeongcheol Yang IEEE 2012 IEEE TRANSACTIONS ON COMMUNICATIONS Vol.60 No.7
<P>The diversity-multiplexing tradeoff (DMT) of a multiple-input multiple-output (MIMO) multiple-access system is analyzed, where a successive cancellation (SC) receiver is employed. In order to analyze the asymptotic performance of each user in a practical MIMO multiple-access system, we derive the per-user DMT considering error propagation due to imperfect cancellation of the SC process. The diversity gain of each user is shown to be expressed as a simple function of the multiplexing gains of the previously detected users as well as its own multiplexing gain. Also, we show that the diversity gain of each user who suffers from error propagation is strictly smaller than that under the assumption of perfect cancellation in a range of multiplexing gains of the users. Numerical results show that our DMT analysis matches well with the performance of practical multiple-access systems.</P>
Design of Length-Compatible Polar Codes Based on the Reduction of Polarizing Matrices
Dong-Min Shin,Seung-Chan Lim,Kyeongcheol Yang IEEE 2013 IEEE TRANSACTIONS ON COMMUNICATIONS Vol.61 No.7
<P>Length-compatible polar codes are a class of polar codes which can support a wide range of lengths with a single pair of encoder and decoder. In this paper we propose a method to construct length-compatible polar codes by employing the reduction of the 2<SUP>n</SUP> × 2<SUP>n</SUP> polarizing matrix proposed by Arikan. The conditions under which a reduced matrix becomes a polarizing matrix supporting a polar code of a given length are first analyzed. Based on these conditions, length-compatible polar codes are constructed in a suboptimal way by codeword-puncturing and information-refreezing processes. They have low encoding and decoding complexity since they can be encoded and decoded in a similar way as a polar code of length 2<SUP>n</SUP>. Numerical results show that length-compatible polar codes designed by the proposed method provide a performance gain of about 1.0 - 5.0 dB over those obtained by random puncturing when successive cancellation decoding is employed.</P>
Lee, Hyo-Jin,Shin, Dong-Min,Yang, Kyeongcheol IEEE 2010 IEEE TRANSACTIONS ON COMMUNICATIONS Vol.58 No.8
<P>In this paper we first analyze some mathematical properties of ergodic capacity and outage capacity functions of the layers in Bell labs layered space-time (BLAST) architectures employing successive decoding and interference cancellation. We then present statistical rate allocation and power allocation methods that optimize the asymptotic performance of BLAST architectures. Since the methods are developed by using ergodic capacity and outage capacity functions of the layers, the allocated rates and powers depend only on a given channel statistic. Finally, we prove that the rate allocation yields a better asymptotic performance than the power allocation. Numerical results show that BLAST architectures with the rate and power allocation perform better by 4 dB and 3 dB, respectively, than a BLAST architecture with the same rate and power in all layers.</P>