• Title/Summary/Keyword: Translational control

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Analysis on Regular Rotational Gait of a Quadruped Walking Robot

  • Kim, Whee-Kuk;Whang Cho;Yi, Byung-Ju
    • Transactions on Control, Automation and Systems Engineering
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    • v.4 no.2
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    • pp.147-155
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    • 2002
  • In this paper, the regular rotational gaits of the quadruped crawling robot are studied. It is assumed that the proposed regular rotational gaits starts from one of six support patterns in a translational gaits and end up with one of six support patterns in a translational gaits. Noting that six support patterns in a regular translational gait belong to two different groups with respect to regular rotational gait, the static stability margin and the maximum rotational displacement during one rotational stride period for the two representative support patterns are investigated. It is expected that the proposed regular rotational gaits will enhance the omni-directional characteristics of the quadruped crawling robot.

Control of asymmetric cell division in early C. elegans embryogenesis: teaming-up translational repression and protein degradation

  • Hwang, Sue-Yun;Rose, Lesilee S.
    • BMB Reports
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    • v.43 no.2
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    • pp.69-78
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    • 2010
  • Asymmetric cell division is a fundamental mechanism for the generation of body axes and cell diversity during early embryogenesis in many organisms. During intrinsically asymmetric divisions, an axis of polarity is established within the cell and the division plane is oriented to ensure the differential segregation of developmental determinants to the daughter cells. Studies in the nematode Caenorhabditis elegans have contributed greatly to our understanding of the regulatory mechanisms underlying cell polarity and asymmetric division. However, much remains to be elucidated about the molecular machinery controlling the spatiotemporal distribution of key components. In this review we discuss recent findings that reveal intricate interactions between translational control and targeted proteolysis. These two mechanisms of regulation serve to carefully modulate protein levels and reinforce asymmetries, or to eliminate proteins from certain cells.

Improvement of Visual Path Following through Velocity Variation (속도 가변을 통한 영상교시 기반 주행 알고리듬 성능 향상)

  • Choi, I-Sak;Ha, Jong-Eun
    • Journal of Institute of Control, Robotics and Systems
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    • v.17 no.4
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    • pp.375-381
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    • 2011
  • This paper deals with the improvement of visual path following through velocity variation according to the coordinate of feature points. Visual path follow first teaches driving path by selecting milestone images then follows the route by comparing the milestone image and current image. We follow the visual path following algorithm of Chen and Birchfield [8]. In [8], they use fixed translational and rotational velocity. We propose an algorithm that uses different translational velocity according to the driving condition. Translational velocity is adjusted according to the variation of the coordinate of feature points on image. Experimental results including diverse indoor cases show the feasibility of the proposed algorithm.

Near Minimum-Time Trajectory Planning for Wheeled Mobile Robots with Piecewise Constant Voltages

  • Park, Jong-Suk;Kim, Munsang;Kim, Byung-Kook
    • 제어로봇시스템학회:학술대회논문집
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    • 2001.10a
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    • pp.30.6-30
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    • 2001
  • We build near minimum-time trajectory planning algorithm for Wheeled mobile robots (WMRs) With Piece-Wise Constant control voltages satisfying i) initial and final postures and velocities as well as ii) voltage constraints We consider trajectory planning problem for cornering motion with a path-deviation requirement for obstacle avoidance. We divide our trajectory planning algorithm for cornering motion into five ordered sections: translational, transient, rotational, transient, and translational sections. Transforming dynamics into uncorrelated form with respect to translational and rotational velocities, we can make controls for translation/rotational velocities to be independent. By planning each section with constant voltages, and integrating five sections with adjustment of numbers of steps, the overall trajectory is planned. The performance is very close to the minimum-time solution, which is validated via simulation studies.

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Position control fo a flexible gantry robot arm using smart actuators (스마트 작동기를 이용한 갠트리형 유연로봇팔의 위치제어)

  • 한상수;최승복
    • 제어로봇시스템학회:학술대회논문집
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    • 1997.10a
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    • pp.1800-1803
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    • 1997
  • This paper presents new feedback actuators to achieve an accurate position control of a flexible gnatry robot arm. the translational motion in the plane is generated by two d.c.motors and controlled by emplying elecor-rheological(ER) clutch acutators. The generated motion can be continuously controlled by controlling the intensity of lectric field imposed to the ER fluid domain which tunes the transmitted torque of the ER clutch. n the other hand, during control action of the translational motion a flexible arm attached to the moving mass produces undesirable oscillatins due to its inherent flexibility. The oscillations are actively suppressed by applying feedback voltages to piezoceramic acutators bonded on the surface of the flexible arm. The control electric fields to be applied to the ER clutch and the control voltage for the piezoceramic actuator are determined via the loop shaping esign procedures(LSDP) in the H.inf. control technique. Comsequently, an accuate positiion control at the end-point of the flexible am is achieved during planar motion.

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Comparative proteomic analysis of peripheral blood mononuclear cells from atopic dermatitis patients and healthy donors

  • Kim, Won-Kon;Cho, Hyun-Ju;Ryu, Su-In;Hwang, Hyang-Ran;Kim, Do-Hyung;Ryu, Hye-Young;Chung, Jin-Woong;Kim, Tae-Yoon;Park, Byoung-Chul;Bae, Kwang-Hee;Ko, Yong;Lee, Sang-Chul
    • BMB Reports
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    • v.41 no.8
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    • pp.597-603
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    • 2008
  • Atopic dermatitis (AD) is a chronic inflammatory skin disease that induces changes in various inflammatory skin cells. The prevalence of AD is as high as 18% in some regions of the world, and is steadily rising. However, the pathophysiology of AD is poorly understood. To identify the proteins involved in AD pathogenesis, a comparative proteomic analysis of protein expression in peripheral blood mononuclear cells isolated from AD patients and healthy donors was conducted. Significant changes were observed in the expressions of fourteen proteins, including the vinculin, PITPNB, and Filamin A proteins. Among the proteins, $\alpha$-SNAP and FLNA decreased significantly, and PITPNB increased significantly in AD patients compared with control subjects; these findings were further confirmed by real-time PCR and Western blot analysis. The comparative proteome data may provide a valuable clue to further understand AD pathogenesis, and several differentially regulated proteins may be used as biomarkers for diagnosis and as target proteins for the development of novel drugs.

Recent Trends in the Treatment of Voice Disorders: Evidence-based Practice and Translational Biology Research (음성 장애 치료 연구의 최근 동향: 증거에 기초한 임상 치료 및 전이 생물학적 연구)

  • Choi, Seong-Hee
    • Phonetics and Speech Sciences
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    • v.2 no.1
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    • pp.99-112
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    • 2010
  • This study attempted to review the recent, high-quality evidence-based practical research related to the treatment effectiveness of voice disorders which focus on randomized controlled trials (RCTs) and translational research of vocal fold tissue engineering for vocal fold regeneration. Methodology including PICO (P; Populations or Patients, I; Interventions, C; Comparison group (control, placebo, gold standard), O; Outcomes or measures made) information for RCTs and animal models (species), regenerative therapy method, and outcomes of translational research for clinical application was summarized and discussed for future voice disorder research.

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Tip position control of translational 1-link flexible arm with tip mass (Tip mass를 갖는 병진운동 1-링크 탄성암 선단의 위치제어)

  • 이영춘;방두열;이성철
    • 제어로봇시스템학회:학술대회논문집
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    • 1993.10a
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    • pp.1036-1041
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    • 1993
  • The tip of the flexible robot arm has to be controlled by the active control reducing vibration because it has residual vibration after getting to desired position. This paper presents an end-point position control of a 1-link flexible robot arm having tip mass by the PID control algorithm. The system is composed of a flexible arm with tip mass, dc servomotor and ballscrew mechanism under translational motion. The feedback signal composed of the tip displacement measured by laser sensor, estimated velocity and acceleration is used to control the base motion. Theoretical results are obtained by applying the Laplace transform and the numerical inversion method to the governing equations. After the flexible robot arm reaches to. the desired position, the residual vibration is controlled by the PID algorithm. This paper gives the simulation and experimental results of end-point responses according to changing tip-mass and arm length. And this algorithm shows good effects of reducing the residual vibration. Approximately, theoretical response is in good agreement with experimental one.

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Gpx3-dependent Responses Against Oxidative Stress in Saccharomyces cerevisiae

  • Kho, Chang-Won;Lee, Phil-Young;Bae, Kwang-Hee;Kang, Sung-Hyun;Cho, Sa-Yeon;Lee, Do-Hee;Sun, Choong-Hyun;Yi, Gwan-Su;Park, Byoung-Chul;Park, Sung-Goo
    • Journal of Microbiology and Biotechnology
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    • v.18 no.2
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    • pp.270-282
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    • 2008
  • The yeast Saccharomyces cerevisiae has defense mechanisms identical to higher eukaryotes. It offers the potential for genome-wide experimental approaches owing to its smaller genome size and the availability of the complete sequence. It therefore represents an ideal eukaryotic model for studying cellular redox control and oxidative stress responses. S. cerevisiae Yap1 is a well-known transcription factor that is required for $H_2O_2$-dependent stress responses. Yap1 is involved in various signaling pathways in an oxidative stress response. The Gpx3 (Orp1/PHGpx3) protein is one of the factors related to these signaling pathways. It plays the role of a transducer that transfers the hydroperoxide signal to Yap1. In this study, using extensive proteomic and bioinformatics analyses, the function of the Gpx3 protein in an adaptive response against oxidative stress was investigated in wild-type, gpx3-deletion mutant, and gpx3-deletion mutant overexpressing Gpx3 protein strains. We identified 30 proteins that are related to the Gpx3-dependent oxidative stress responses and 17 proteins that are changed in a Gpx3-dependent manner regardless of oxidative stress. As expected, $H_2O_2$-responsive Gpx3-dependent proteins include a number of antioxidants related with cell rescue and defense. In addition, they contain a variety of proteins related to energy and carbohydrate metabolism, transcription, and protein fate. Based upon the experimental results, it is suggested that Gpx3-dependent stress adaptive response includes the regulation of genes related to the capacity to detoxify oxidants and repair oxidative stress-induced damages affected by Yap1 as well as metabolism and protein fate independent from Yap1.