• 제목/요약/키워드: LTR

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Genomic Features of Retroelements and Implications for Human Disease

  • Kim, Heui-Soo
    • Genomics & Informatics
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    • v.3 no.4
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    • pp.133-141
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    • 2005
  • Most of the endogenous retroviral genes integrated into the primate genome after the split of New World monkeys in the Oligocene era, approximately 33 million years ago. Because they can change the structure of adjacent genes and move between and within chromosomes they may play important roles in evolutionas well as in many kinds of disease and the creation of genetic polymorphism. Comparative analysis of HERVs (human endogenous retroviruses) and their LTR (long terminal repeat) elements in the primate genomes will help us to understand the possible impact of HERV elements in the evolution and phylogeny of primates. For example, HERV-K LTR and SINE-R elements have been identified that have been subject to recent change in the course of primate evolution. They are specific elements to the human genome and could be related to biological function. The HERV-M element is related to the superfamily of HERV-K and is integrated into the periphilin gene as the truncated form, 5'LTR-gag-pol-3'LTR. PCR and RT-PCR approaches indicated that the insertion of various retrotransposable elements in a common ancestor genome may make different transcript variants in different primate species. Examination of the HERV-W elementrevealed that env fragments were detected on human chromosomes 1, 3-7, 12, 14, 17, 20, and X, whilst the pol fragments were detected on human chromosomes 2-8, 10-15, 20, 21, X, and Y. Bioinformatic blast search showed that almost full-length of the HERV-W family was identified on human chromosomes 1-8, 11-15, 17, 18, 21, and X. Expression analysis of HERV-W genes (gag, pol, and env) in human tissues by RT-PCR indicated that gag and pol were expressed in specific tissues, whilst env was constituitively expressed in all tissues examined. DNA sequence based phylogenetic analysis indicated that the gag, pol and env genes have evolved independently during primate evolution. It will thus be of considerable interest to expand the current HERV gene information of various primates and disease tissues.

Robust Autopilot Design for Nonsquare Flight Systems (비정방 비행 시스템에 대한 강인한 자동조종장치 설계)

  • 김종식;정성훈
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.17 no.5
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    • pp.1123-1131
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    • 1993
  • A robust controller is proposed to design a flight autopilot for lateral motion control. The control system has two control loops in order to meet the performance and to maintain the stability-robustness for a nonsquare flight system with uncertain aerodynamic variations and disturbance. One is designed via linear quadratic Gaussian with loop transfer recovery(LQG/LTR) design methodology for the inner loop. The other is designed via proportional controller design method for the outer loop. To show the effectiveness of this control system, it is compared with the LQG/LTR control system for a square flight system and is analyzed for the performance/stability-robustness to model uncertainties and disturbance via wind gusts. It is found that the proposed control system has good heading command-following performance under allowable sideslip angle in spite of model uncertainties and disturbance.

Characterization of the Bovine Endogenous Retrovirus β3 Genome

  • Xiao, Rui;Kim, Juhyun;Choi, Hojun;Park, Kwangha;Lee, Hoontaek;Park, Chankyu
    • Molecules and Cells
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    • v.25 no.1
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    • pp.142-147
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    • 2008
  • We recently used degenerate PCR and locus-specific PCR methods to identify the endogenous retroviruses (ERV) in the bovine genome. Using the ovine ERV classification system, the bovine ERVs (BERVs) could be classified into four families. Here, we searched the most recently released bovine genome database with the partial nucleotide sequence of the pro/pol region of the BERV ${\beta}3$ family. This allowed us to obtain and analyze the complete genome of BERV ${\beta}3$. The BERV ${\beta}3$ genome is 7666 nucleotides long and has the typical retroviral organization, namely, 5'-long terminal repeat (LTR)-gag-pro-pol-env-LTR-3'. The deduced open reading frames for gag, pro, pol and env of BERV ${\beta}3$ en- code 507, 271, 879 and 603 amino acids, respectively. BERV ${\beta}3$ showed little amino acid similarity to other betaretroviruses. Phylogenetic analysis showed that it clusters with HERV-K. This is the first report describing the genetic structure and sequence of an entire BERV.

Evolutionary course of CsRn1 long-terminal-repeat retrotransposon and its heterogeneous integrations into the genome of the liver fluke, Clonorchis sinensis

  • Bae, Young-An;Kong, Yoon
    • Parasites, Hosts and Diseases
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    • v.41 no.4
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    • pp.209-219
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    • 2003
  • The evolutionary course of the CsRn1 long-terminal-repeat (LTR) retrotransposon was predicted by conducting a phylogenetic analysis with its paralog LTR sequences. Based on the clustering patterns in the phylogenetic tree, multiple CsRn1 copies could be grouped into four subsets, which were shown to have different integration times. Their differential sequence divergences and heterogeneous integration patterns strongly suggested that these subsets appeared sequentially in the genome of C. sinensis. Members of recently expanding subset showed the lowest level of divergence in their L TR and reverse transcriptase gene sequences. They were also shown to be highly polymorphic among individual genomes of the trematode. The CsRn1 element exhibited a preference for repetitive, agenic chromosomal regions in terms of selecting integration targets. Our results suggested that CsRn1 might induce a considerable degree of intergenomic variation and, thereby, have influenced the evolution of the C. sinensis genome.

Design of the flexible switching controller for small PWR core power control with the multi-model

  • Zeng, Wenjie;Jiang, Qingfeng;Du, Shangmian;Hui, Tianyu;Liu, Yinuo;Li, Sha
    • Nuclear Engineering and Technology
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    • v.53 no.3
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    • pp.851-859
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    • 2021
  • Small PWR can be used for power generation and heating. Considering that small PWR has the characteristics of flexible operating conditions and complex operating environment, the controller designed based on single power level is difficult to achieve the ideal control of small PWR in the whole range of core power range. To solve this problem, a flexible switching controller based on fuzzy controller and LQG/LTR controller is designed. Firstly, a core fuzzy multi-model suitable for full power range is established. Then, T-S fuzzy rules are designed to realize the flexible switching between fuzzy controller and LQG/LTR controller. Finally, based on the core power feedback principle, the core flexible switching control system of small PWR is established and simulated. The results show that the flexible switching controller can effectively control the core power of small PWR and the control effect has the advantages of both fuzzy controller and LQG/LTR controller.

Robust Control of Two-axes Precise Stage Using LMI Optimization (LMI 최적화를 이용한 2축 정밀 스테이지의 강인제어)

  • Kim, Yeung-Shik;Park, Heung-Seok;Kim, In-Soo
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.22 no.5
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    • pp.845-851
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    • 2013
  • In this paper, a robust optimization approach is applied to the two-axes stage using a piezoelectric actuator for precise motion tracking. Robust control is based on LQG/LTR (linear quadratic Gaussian control with loop transfer recovery) control. Further, an LMI (linear matrix inequality) is used to find the optimal parameter in the loop transfer recovery step, instead of a trial and error method. A decoupler in the shape of FIR filter is added to reduce the coupling effect between the motions of the two axes, and hence, the feedback control loop is designed independently for each axis motion. The experimental result shows that the proposed control scheme can be applied effectively for motion control of the two-axes stage.

A design on model following optimal boiler-turbine H$\infty$control system using genetic algorithm (유전 알고리즘을 이용한 모델 추종형 최적 보일러-터빈 H$\infty$ 제어시스템의 설계)

  • 황현준;김동완;박준호;황창선
    • 제어로봇시스템학회:학술대회논문집
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    • 1997.10a
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    • pp.1460-1463
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    • 1997
  • The aim of this paper is to suggest a design method of the model following optimal boiler-turbine H.inf. control system using genetic algorithm. This boiler-turbine H.inf. control system is designed by applying genetic algortihm with reference model to the optimal determination of weighting functions and design parameter .gamma. that are given by Glover-Doyle algornithm whch can design H.inf. contrlaaer in the sate. space. The first method to do this is ghat the gains of weightinf functions and .gamma. are optimized simultaneously by genetic algroithm. And the second method is that not only the gains and .gamma. but also the dynamics of weighting functions are optimized at the same time by genetic algonithm. The effectiveness of this boiler-turbine H.inf. control system is verified and compared with LQG/LTR control system by computer simulation.

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Critical Control Systems Design via LTR Technique

  • Ishihara, Tadashi;Imai, Minoru;Ono, Takahiko;Inooka, Hikaru
    • 제어로봇시스템학회:학술대회논문집
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    • 2003.10a
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    • pp.19-24
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    • 2003
  • A new method for designing critical control systems is proposed in this paper. The controller structure is chosen as a Davison type integral controller with an observer. The proposed method consists of two steps. First, the state feedback critical control system is designed using a quadratic performance index with tunable parameters. Second, the observer gain matrix is determined by the formal LTR procedure using a Riccati equation. Consequently, the search space can be reduced considerably compared with the conventional approach. Although the proposed method sacrifices a large freedom for the choice of controller structure provided by the principle of matching, the controller structure used in this paper is not excessively complex and can be used for most applications. An illustrative design example is presented.

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Development of an Unmanned Vechile Driving System by the MPC sensors

  • Shin, Taek-Young;Ha, Sung-Ki;Jeong, Seung-Gweon;Kim, Chang-Sub;Lee, Man-Hyoung
    • 제어로봇시스템학회:학술대회논문집
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    • 2003.10a
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    • pp.1207-1210
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    • 2003
  • In this paper, studied traveling by ummaned vehicles using MPC sensor.Explain what is MPC sensor and also is threaded how on vehicles. Made use of PID controller and LQG/LTR controller that is used much in present industrial circles for control of this.

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