• Title/Summary/Keyword: ICI

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Binding of IciA protein to the dnaA promoter region

  • Kim, Hakjung;Hwang, Deog-Su
    • Journal of Microbiology
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    • v.33 no.3
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    • pp.191-195
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    • 1995
  • IciA protein has been shown as an inhibitor for the initiation of E. coli chromosomal DNA replication at oriC. IciA protein binds the AT-rich region in oriC and then blocks the initiation of chromosomal DNA replication. Two binding sites for IciA protein were identified in dnaA gene, encoding the initiator for the E. coli chromosomal replication, promoter region by gel-shift assay and DNase I footprinting, One, named as IciA site I, is located upstream of the dnaA promoter 1P. The other, named as IciA site II, is located downstream of the dnaA promoter 2P. The sequence comparison of the regions protected from the DNase I cleavage did not result in a clear consensus sequence for the binding of IciA protein, suggesting that IciA protein may be a member of multimeric complex dsDNA binding proteins. This study provided information about the binding mode of IciA protein. Even though the IciA site II and IciA binding site in oriC seem to be composed of two IciA binding units, one binding unit is likely enough to cause the binding of IciA protein to the IciA site I. The binding of IciA protein to the dna4 promoter implies that IciA protein may involve not only the control of the initiation of chromosomal DNA replication but also the control of the dna4 gene expression.

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A Design of OFDM Signal for Reducing the ICI Caused by Phase Noise (위상잡음에 의한 ICI를 제거하기 위한 OFDM 신호 설계)

  • Li Yingshan;Hieu Nguyen Thanh;Ryu Heung-Gyoon;Jeong Young-Hoo;Hahm Young-Kown
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.16 no.3 s.94
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    • pp.319-326
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    • 2005
  • In the multi-carrier OFDM communication system for the high data rate transmission, the ICI caused by phase noise of transceiver local oscillator may degrade the system performance seriously. In this paper, a new ICI self-cancellation scheme using data-conjugate method is proposed to reduce the ICI caused by phase noise effectively. Then, the CPE, ICI and CIR are derived by the phase noise linear approximation method. Besides, to analyze the efficiency of system performance improvement, the proposed method is compared with the original OFDM and the conventional ICI self-cancellation scheme using data-conversion method. As results, the performance degradation caused by ICI can be mitigated effectively in the OFDM system with ICI self-cancellation scheme, and more performance improvement can be achieved by the proposed ICI self-cancellation scheme using data-conjugate method than the conventional ICI self-cancellation scheme using data-conversion method when phase noise exists.

Effects of Alternate Treatment of Estrogen Receptor Antagonist and Agonist on Morphology of Male Reproductive Organs of Adult Mice

  • Choi, Hayana;Seong, Chi Nam;Park, Mi Suk;Cho, Hyun Wook
    • Applied Microscopy
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    • v.43 no.3
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    • pp.103-109
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    • 2013
  • ICI 182,780 (ICI) is known as an estrogen receptor antagonist, whereas propyl pyrazole triol (PPT) is an estrogen receptor agonist. In this study, ICI or ICI added with PPT was injected into adult male mice. Body and reproductive organ weights were reduced in the ICI added with PPT group compared to the control group. Further, the ICI and ICI added with PPT groups both showed increases in luminal areas of the seminiferous tubules of the testis, whereas cell heights of efferent ductules and the initial segment of the epididymis were reduced. Sperm count in the caudal epididymis was reduced in the ICI and ICI added with PPT groups. These results show that reproductive tissues were more deeply affected in the ICI added with PPT group. We also demonstrated that treatment with ICI resulted in histological changes in the testis, efferent ductule, and epididymis. Further, alternate treatment with ICI and PPT induced abnormalities in reproductive organs. These results indicate that a high concentration of PPT together with ICI may cause histological abnormalities instead of histological restoration in reproductive organs.

Performance Analysis of OFDM Communication System Cancelling the ICI by Data Conversion Method (ICI를 Data Conversion 방식으로 상쇄하는 OFDM 통신시스템과 성능분석)

  • 허근재;이영선;유흥균;정두영
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.14 no.11
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    • pp.1191-1197
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    • 2003
  • In the multi-carrier OFDM communication system, the inter-carrier-interference(ICI) produced by phase noise in the transceiver local oscillator makes a severe influence on the system performance. In this paper, a new ICI self-cancellation scheme in the data-conversion type is proposed to reduce effectively the ICI. Also, the common phase error(CPE), ICI and carrier to interference power ratio(CIR) are found by the linear approximation of the phase noise. Then, the proposed method is compared with the conventional OFDM to analyze the efficiency of system performance improvement. When the number of subcarriers is 64, there are respectively the SNR gain of 0.6 ㏈ in the phase noise variance of 0.3 with QPSK and 1.5 ㏈ in the phase noise variance of 0.1 with 16 QAM at BER=10$\^$-3/. As a result, the performance degradation by ICI can be effectively lowered in the proposed system with ICI self. cancellation scheme, compared with the conventional OFDM system.

Performance Analysis of ICI reduction in OFDM system (OFDM시스템에서 ICI 감소 기술의 성능해석)

  • Jang, Eun-Young;Byon, Kun-Sik
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.11 no.6
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    • pp.1150-1155
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    • 2007
  • Orthogonal Frequency Division Multiplexing (OFDM) is an emerging multi-carrier modulation scheme, which has been adopted for several wireless standards such as IEEE 802.11a and HiperLAN2. A well-known problem of OFDM is its sensitivity to frequency offset between the transmitted and received carrier frequencies. This frequency offset introduces inter-carrier interference (ICI) in the OFDM symbol. This paper investigates three methods for combating the effects of ICI: ICI self-cancellation (SC), maximum likelihood (ML) estimation, and extended Kalman filter (EKF) method. These three methods are compared in terms of bit error rate performance.

Crystallization of Escherichia coli IciA Protein An Initiation of Chroirnsomal Replication (대장균 염색체 복제 개시 저해제, IciA 단백질의 결정화)

  • Song, Hyun-Kyu;Cha, Hoon;Yoo, Soon-Ji;Chung, Chin-Ha;Hwang, Deog-Su;Suh, Se-Won
    • Korean Journal of Crystallography
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    • v.5 no.1
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    • pp.20-23
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    • 1994
  • Specific binding to the oric region of E, coli chromsome by IciA protein inhibits initiation of chrorrnsomal replication in vitro by blocking the opening of this region effected by the initiator DnaA protein. The IciA protein has been suggested play a critical role in a key stage of the cell cycle. In order to study the structure-function relationship of IciA protein, we are determining the three-dimensional structure of IciA Votein by X-ray crystallography, As a first step toward its structure detumination E. coli IciA protein has been crystallized using sodium formate as a precipitant.

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A Recursive ICI Cancellation Technique for Cooperative STBC-OFDM Systems with Carrier Frequency Offsets (반송파 주파수 옵셋을 갖는 상호협력 STBC-OFDM 시스템을 위한 반복적 ICI 제거 기법)

  • Kim, Yeong-Jun;Woo, Kyung-Soo;Yoo, Hyun-Il;Lee, Hee-Soo;Cho, Yong-Soo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.32 no.10A
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    • pp.950-957
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    • 2007
  • In this paper, a recursive intercarrier interference (ICI) cancellation technique for cooperative space-time block coded orthogonal frequency division multiplexing (STBC-OFDM) with different carrier frequency offsets (CFOs) is proposed. Also, different CFOs existing in a cooperative STBC-OFDM system is shown to produce phase difference in the received signal, causing noise enhancement effect in the STBC decoding process. The performance degradation caused by the noise enhancement effect can be effectively reduced by a proposed ML-based recursive ICI cancellation technique. It is shown by computer simulation that the proposed recursive ICI cancellation technique is effective in reducing ICI, especially for STBC-OFDM systems with a large FFT size and large CFOs.

An Enhanced Iterative ICI Cancellation Method for Cooperative STBC-OFDM Systems (상호 협력 STBC-OFDM 시스템을 위한 개선된 반복적 ICI 제거 기법)

  • Won, Kyung-Hoon;Park, Hwan-Min;Choi, Hyung-Jin
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.34 no.9C
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    • pp.896-905
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    • 2009
  • In this paper, we propose an enhanced iterative ICI (Inter Carrier Interference) cancellation method for cooperative STBC-OFDM (Space Time Block Coded-Orthogonal Frequency Division Multiplexing) system. In cooperative STBC-OFDM system, ICI cancellation is necessary because ICI due to the independent local oscillators always exits. The conventional iterative ICI cancellation method has severe performance degradation due to the initial estimation error. Also the performance degradation increases as CFOs (Carrier Frequency Offsets) and modulation order increases. Therefore, in this paper, we propose an enhanced iterative ICI cancellation method which can reduce the initial estimation error by giving a priority to initial estimation and cancellation process. Through the complexity and performance comparisons, we verwey that the proposed method has better performance with approximately same complexity compared with the conventional method.

An Efficient ICI Self-Cancellation Method with Frequency Offset and Phase Noise in OPDM Systems (OFDM 시스템에서 주파수 오차와 위상 잡음에 의한 ICI를 제거하기 위한 효율적인 자가상쇄 기법)

  • Park, Jeong-Hwan;Kim, Hyung-Myung
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.34 no.2A
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    • pp.155-163
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    • 2009
  • OFDM System is a promising transmission technique due to its spectral efficiency But, a major disadvantage of the OFDM system is its sensitivity to frequency offset and phase noise that makes intercarrier interference (ICI), which degrades the system performance severely The ICI self-cancellation method has a good performance with frequency offset or phase noise. This paper proposed the N/2 spacing data-conjugate method that works well in large frequency offset and phase noise (normalized frequency offset=0.2-0.4, phase noise standard deviation=about lodes). Also, an efficiency ICI cancellation method using pilot was proposed. Simulation results confirm that performance of the proposed scheme is better than conventional schemes.

Phase Noise Compensation in OFDM Communication System by STFBC Method (OFDM 통신 시스템에서 STFBC 기법을 이용한 위상잡음 보상)

  • Li Yingshan;Ryu Heung-Gyoon;Jeong YoungHo
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.16 no.10 s.101
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    • pp.1043-1049
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    • 2005
  • In OFDM system suitable for high capacity high speed broadband transmission, ICI caused by phase noise degrades system performance seriously by destroying the orthogonality among subcarriers. In this paper, a new STFBC method combining ICI self cancellation scheme and antenna, time, frequency diversity is studied to reduce ICI effectively. CPE and ICI are analyzed by the phase noise linear approximation method in the proposed STFBC OFDM system. CIR, PICR and BER are discussed to compare the system performance degraded by phase noise of PLL. As results, STFBC method significantly reduces ICI. Furthermore, the SCI that usually happens in the traditional STBC, SFBC diversity coding method can be easily avoided.