• Title/Summary/Keyword: domain dynamics

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A Modelling of magnetization reversal characteristics in magneto-optic memory system (광자기 기억장치에서의 자화반전 특성 모델링)

  • 한은실;이광형;조순철
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.19 no.10
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    • pp.1849-1860
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    • 1994
  • Domain wall dynamics in thin film of amorphous Rare Earth-Transistion Metal alloys were investigated using numerical integration of the Landau-Lifshitz-Gilbert equation. The thin film was divided into a two-dimensional square lattice ($30\times30$) of dipoles. Nearest-neighbor exchange interaction magnetic anisotropy, applied magnetic field, and demagnetiing field of interacting anisotropy, applied magnetic field, and demagnetizing field of interacting dipoles were considered. It was assumed that the film had perfect uniaxial anisotropy in the perpendicular direction and the magnetization reversal existed in the film. The time of domain wall creation and the thickness of the wall were investigated. Also the motion of domain walls under an applied field was considered. Simulation results showed that the time of domain wall creation was decreased significantly and the average velocity of domain wall was increased somewhat when the demagnetizing field was considered.

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Functional Role of a Conserved Sequence Motif in the Oxygen-dependent Degradation Domain of Hypoxia-inducible Factor 1α in the Recognition of p53

  • Chi, Seung-Wook
    • Genomics & Informatics
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    • v.6 no.2
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    • pp.72-76
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    • 2008
  • Hypoxia-inducible factor $1{\alpha}\;(HIF1{\alpha})$ is a transcription factor that plays a key role in the adaptation of cells to low oxygen stress and oxygen homeostasis. The oxygen-dependent degradation (ODD) domain of $HIF1{\alpha}$ is responsible for the negative regulation of $HIF1{\alpha}$ in normoxia. The interactions of the $HIF1{\alpha}$ ODD domain with partner proteins such as von Hippel-Lindau tumor suppressor (pVHL) and p53 are mediated by two sequence motifs, the N- and C-terminal ODD(NODD and CODD). Multiple sequence alignment with $HIF1{\alpha}$ homologs from human, monkey, pig, rat, mouse, chicken, frog, and zebrafish has demonstrated that the NODD and CODD motifs have noticeably high conservation of the primary sequence across different species and isoforms. In this study, we carried out molecular dynamics simulation of the structure of the $HIF1{\alpha}$ CODD motif in complex with the p53 DNA-binding domain (DBD). The structure reveals specific functional roles of highly conserved residues in the CODD sequence motif of $HIF1{\alpha}$ for the recognition of p53.

Inverse Compensation of Hysteresis in Ferromagnetic Materials (강자성체의 히스테리시스 역 보상 모델)

  • 박영우;한광섭
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2004.10a
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    • pp.1470-1474
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    • 2004
  • This paper addresses the development of inverse compensation techniques for a class of ferromagnetic transducers including magnetostrictive actuators. In this work, hysteresis is modeled through the domain wall theory originally proposed by Jiles and Atherton[1]. This model is based on the quantification of the energy required to translate domain walls pinned at inclusions in the material with the magnetization at a given field level specified through the solution of an ordinary differential equation. A complementary differential equation is then employed to compute the inverse which can be used to compensate for hysteresis and nonlinear dynamics in control design.

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A Study on the Relationship Dynamics of Perpetration and Victimization in Early Adult Couples according to the Types of Dynamics in Dating Violence (성인 초기 커플의 데이트폭력 유형에 따른 가해와 피해에 대한 관계 역동 연구)

  • Kyung Eun Park
    • Korean Journal of Culture and Social Issue
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    • v.29 no.4
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    • pp.497-536
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    • 2023
  • This study was conducted with the purpose of exploring the relationship dynamics of couples who experienced dating violence. For this purpose, interviews were conducted with 15 couples who experienced dating violence. The collected data was analyzed using the consensual qualitative research(CQR) method. As a result, 3 domains, 13 categories, and 30 subcategories were derived. Domain 1 was about "the direction of the dynamics of perpetration and victimization, types of violence, and experience level," and found that the dynamics of perpetration and victimization are bidirectional, and that there are situational and controlling types of violence. For domain 2, we explored "major conflict themes, unique perceptions, and psychological dynamics of violence" and identified "other and communication issues" and "interference and personality issues" as major conflict themes, "gender stereotypes" and "violence permissive beliefs" as unique perceptions, and "attribution styles," "major emotions," and "coping styles" as psychological dynamics of violence. For domain 3, we looked into the 'changes in commitment and satisfaction as well as relationship maintenance factors' and presented changes in commitment and satisfaction, and found that the relationship maintenance factors were divided into positive and negative factors. These results are significant in that dating violence consists of mutual abuse and that it empirically revealed the detailed elements of the psychological dynamics of male and female. This was compared and analyzed with previous studies, and limitations and future research were also presented.

Iterative learning control of robot manipulators (로봇 매니퓰레이터의 반복 학습 제어)

  • 문정호;도태용;정명진
    • 제어로봇시스템학회:학술대회논문집
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    • 1996.10b
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    • pp.470-473
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    • 1996
  • This paper presents an iterative learning control scheme for industrial manipulators. Based upon the frequency-domain analysis, the input update law of the learning controller is given together with a sufficient condition for the convergence of the iterative process in the frequency domain. The proposed learning control scheme is structurally simple and computationally efficient since it is independent joint control depending only on locally measured variables and it does not involve the computation of complicated nonlinear manipulator dynamics. Moreover, it is capable of canceling the unmodeled dynamics of the manipulator without even the parametric model. Several important aspects of the learning scheme inherent in the frequency-domain design are discussed and the control performance is demonstrated through computer simulations.

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DOMAIN WALL DYNAMICS AND EQUIVALENT CIRCUTTS IN FERROMAGNETIC MATERIALS

  • Valinzuela, R.
    • Proceedings of the Materials Research Society of Korea Conference
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    • 1992.05a
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    • pp.8-8
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    • 1992
  • The study of magnetic properties of ferro and ferri-magnetic materials has shown that, due to their different time constants, magnetisation mechanisms (domain wall displacement, spin rotation and wall bulging) can be separated by using the complex permeability formalisms, they exhibit characteristic features in $\mu$′ versus $\mu$" plots. In many cases. the elements (inductances, resistances and capacitances) of the equivalent circuit representing the friquency behaviour, can also be associated with physical parameters of the sample [1-3]. In a different approach, domain wall dynamics can be represented by a motion equation with mass, damping and restoring force terms [4]. In this paper, we show that these two approaches are consistent and how they are related.

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Dynamic and structural responses of a submerged floating tunnel under extreme wave conditions

  • Jin, Chungkuk;Kim, MooHyun
    • Ocean Systems Engineering
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    • v.7 no.4
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    • pp.413-433
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    • 2017
  • The dynamic and structural responses of a 1000-m long circular submerged floating tunnel (SFT) with both ends fixed under survival irregular-wave excitations are investigated. The floater-mooring nonlinear and elastic coupled dynamics are modeled by a time-domain numerical simulation program, OrcaFlex. Two configurations of mooring lines i.e., vertical mooring (VM) and inclined mooring (IM), and four different buoyancy-weight ratios (BWRs) are selected to compare their global performances. The result of modal analysis is included to investigate the role of the respective natural frequencies and elastic modes. The effects of various submergence depths are also checked. The envelopes of the maximum/minimum horizontal and vertical responses, accelerations, mooring tensions, and shear forces/bending moments of the entire SFT along the longitudinal direction are obtained. In addition, at the mid-section, the time series and the corresponding spectra of those parameters are also presented and analyzed. The pros and cons of the two mooring shapes and high or low BWR values are systematically analyzed and discussed. It is demonstrated that the time-domain numerical simulation of the real system including nonlinear hydro-elastic dynamics coupled with nonlinear mooring dynamics is a good method to determine various design parameters.

Time-domain Approaches for Input Disturbance Observer

  • Kim, Kyung-Soo
    • 제어로봇시스템학회:학술대회논문집
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    • 2005.06a
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    • pp.22-25
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    • 2005
  • In the paper, algorithms for disturbance observers are newly presented in the time-domain. Attention is paid to observing a ramp disturbance by introducing an integral term to the output equation of a constant disturbance observer. In order to reduce the sensitivity to the measurement noise, the disturbance observer is combined with the state observer. It will be shown that the estimation dynamics can be arbitrarily chosen by assigning the eigenvalues of a characteristic equation. Also, we provide the analysis of observer behaviors subject to non-ramp-style disturbances. Finally, we propose the generalized disturbance observer that accurately estimates disturbances of higher order in time series expansion.

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