• Title/Summary/Keyword: Self-stabilizing

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A B-Spline Higher Order Panel Method for Analysis of Three Dimensional Potential Flow (B-스플라인 고차패널법에 의한 3차원 포텐셜 유동 해석)

  • Gun-Do. Kim;Ui-Sang Hwang;Chang-Sup Lee
    • Journal of the Society of Naval Architects of Korea
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    • v.37 no.2
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    • pp.57-69
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    • 2000
  • A higher order panel method based on representation for both the geometry and the velocity potential is developed for the analysis of steady flow around marine propellers. The self-influence functions due to the normal dipole and the source are desingularized through the quadratic transformation, and then the singular part is integrated analytically whereas the non-singular part is integrated using Gaussian quadrature. A null pressure jump Kutta condition at the trailing edge is found to be effective in stabilizing the solution process and in predicting the correct solution. Numerical experiments indicate that the present method is robust and predicts the pressure distribution around lifting bodies with much fewer panels than existing low order panel methods.

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ERUPTION GUIDANCE OF MAXILLARY PREMOLARS WITH DELAYED DEVELOPMENT (지연발육 상악 소구치의 맹출 유도)

  • Ha, Na;Kim, Youngjin;Kim, Hyunjung;Nam, Soonhyeun
    • The Journal of Korea Assosiation for Disability and Oral Health
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    • v.13 no.1
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    • pp.6-13
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    • 2017
  • Premolars show the greatest variation in development and eruption. The present case report identified characteristics of eruption of maxillary premolars with delayed development. Multiple maxillary premolars with delayed development were found to have a palatal ectopic eruption pattern, which was self-corrected through eruption guidance by extraction of preceding primary teeth at the stage of root development when eruption force was maximal. In addition, delayed eruption due to delayed development was substantially improved by eruption guidance. Early erupted premolars with less than 1/3 of root development were induced to have normal root development using stabilizing appliance. The maxillary premolars with delayed development reported in the present study showed no complications such as impaction, space loss by delayed eruption, or insufficient root development.

Effects of Imagery on Stress, Anxiety, and Immune Cells in Patients with Acute Leukemia Receiving Chemotherapy (심상요법이 항암화학요법을 받는 급성 백혈병 환자의 스트레스, 불안 및 면역세포에 미치는 효과)

  • Shim, Soo Kyung;Kim, Nam-Cho
    • Korean Journal of Adult Nursing
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    • v.19 no.5
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    • pp.115-126
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    • 2007
  • Purpose: The present study is a quasi-experimental research for examining the effects of imagery on stress, anxiety and immune cells in acute leukemia patients receiving chemotherapy and utilizing the therapy for their self control and stress management. Methods: The subjects were 60 patients who were diagnosed with acute leukemia and scheduled to receive chemotherapy at A hospital in Seoul during the period from November 2006 to March 2007. After the start of chemotherapy, the experimental group received imagery for 4 weeks, three sessions a week, so a total of 12 sessions and 156 minutes. Results: The decrease of stress was larger in the experimental group than in the control group. Systolic blood pressure decreased significantly more in the experimental group than in the control group. In the experimental group, state anxiety decreased significantly in the 2nd week of the experiment and after the final stage of the experiment. The total number of white blood cells, and the absolute number of neutrophils and lymphocytes were showing significant differences between the time points. Conclusion: Imagery is an effective intervention for reducing stress and state anxiety and stabilizing blood pressure in acute leukemia patients receiving chemotherapy.

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Vibration Control a Flexible Single Link Robot Manipulator Using Neural Networks (신경회로망을 이용한 유연성 단일 링크 로봇 매니퓰레이터의 진동제어)

  • 탁한호;이상배
    • Journal of the Korean Institute of Navigation
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    • v.21 no.3
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    • pp.55-66
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    • 1997
  • In this paper, applications of neural networks to vibration control of flexible single link robot manipulator are ocnsidered. The architecture of neural networks is a hidden layer, which is comprised of self-recurrent one. Tow neural networks are utilized in a control system ; one as an identifier is called neuro identifier and the othe ra s a controller is called neuro controller. The neural networks can be used to approximate any continuous function to any desired degree of accuracy and the weights are updated by dynamic error-backpropagation algorithm(DEA). To guarantee concegence and to get faster learning, an approach that uses adaptive learning rates is developed by introducing a Lyapunov function. When a flexible manipulator is ratated by a motor through the fixed end, transverse vibration may occur. The motor torque should be controlle dinsuch as way, that the motor is rotated by a specified angle. while simulataneously stabilizing vibration of the flexible manipulators so that it is arrested as soon as possible at the end of rotation. Accurate vibration control of lightweight manipulator during the large body motions, as well as the flexural vibrations. Therefore, dynamic models for a flexible single link manipulator is derived, and LQR controller and nerual networks controller are composed. The effectiveness of the proposed nerual networks control system is confirmed by experiments.

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Conformational Preference of Pseudo-Proline Dipeptide in the Gas Phase and Solutions

  • Park, Hae-Sook;Kang, Young-Kee
    • Proceedings of the Korean Biophysical Society Conference
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    • 2003.06a
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    • pp.74-74
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    • 2003
  • We report here the results on N-acetyl-N'-methylamide of oxazolidine (Ac-Oxa-NHMe) calculated using the ab initio molecular orbital method with the self-consistent reaction field (SCRF) theory at the HF level of theory with the 6-3l+G(d) basis set. The displacement of the $\square$-CH$_2$ group in proline ring by oxygen atom has affected the structure of proline, cis$\^$∼/ trans equilibrium, and rotational barrier. The up-puckered structure is found to be prevalent for the trans conformers of the Oxa amide. The higher cis populations of the Oxa amide can be interpreted due to the longer distance between the acetyl methyl group and the 5-methylene group of the ring for the trans conformer of the Oxa amide than that of the Pro amide. The changes in charge of the prolyl nitrogen and the decrease in electron overlap of the C$\^$∼/ N bond for TS structures seem to play a role in lowering rotational barriers of the Oxa amide compared to that of the Pro amide. The calculated preferences for cis conformers in the order of Oxa > Pro amides and for trans-to-cis rotational barriers in the order of Pro > Oxa amide in water are consistent with experimental results on Oxa-containing peptides. The pertinent distance between the prolyl nitrogen and the N$\^$∼/ H amide group to form a hydrogen bond might indicate that this intramolecular hydrogen bond could contribute in stabilizing the TS structures of Oxa and Pro amides and play a role in prolyl isomerization.

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Surface Coating and Electrochemical Properties of LiNi0.8Co0.15Al0.05O2 Polyaniline Composites as an Electrode for Li-ion Batteries

  • Chung, Young-Min;Ryu, Kwang-Sun
    • Bulletin of the Korean Chemical Society
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    • v.30 no.8
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    • pp.1733-1737
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    • 2009
  • A new cathode material based on Li$Ni_{0.8}Co_{0.15}Al_{0.05}O_2$ (LNCA)/polyaniline (Pani) composite was prepared by in situ self-stabilized dispersion polymerization in the presence of LNCA. The materials were characterized by fourier transform infrared spectroscopy (FT-IR), ultraviolet-visible spectroscopy (UV-Vis), X-ray diffraction (XRD), and scanning electron microscopy (SEM). Electrochemical properties including galvanostatic charge-discharge ability, cyclic voltammetry (CV), capacity, cycling performance, and AC impedance were measured. The synthesized LNCA/Pani had a similar particle size to LNCA and exhibited good electrochemical properties at a high C rate. Pani (the emeraldine salt form) interacts with metal-oxide particles to generate good connectivity. This material shows good reversibility for Li insertion in discharge cycles when used as the electrode of lithium ion batteries. Therefore, the Pani coating is beneficial for stabilizing the structure and reducing the resistance of the LNCA. In particular, the LNCA/Pani material has advantageous electrochemical properties.

Analysis of Two-dimensional Hydrofoil Problems Using Higher Order Panel Method based on B-Splines (B-스플라인 고차패널법에 의한 2차원 수중익 문제 해석)

  • Chung-Ho Cho;Gun-Do Kim;Chang-Sup Lee
    • Journal of the Society of Naval Architects of Korea
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    • v.36 no.4
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    • pp.9-20
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    • 1999
  • A higher order panel method based on B-spline representation for both the geometry and the velocity potential is developed for the solution of the flow around two-dimensional lifting bodies. The self-influence functions due to the normal dipole and the source are separated into the singular and nonsingular parts, and then the former is integrated analytically whereas the latter is integrated using Gaussian quadrature. A null pressure jump Kutta condition at the trailing edge is found to be effective in stabilizing the solution process and in predicting the correct solution. Numerical experiments indicate that the present method is robust and predicts the pressure distribution around lifting foils with much fewer panels than existing low order panel methods.

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Application of High Order Panel Method for Improvement of Prediction of Marine Propeller Performance (프로펠러 단독성능해석 향상을 위한 고차패널법의 적용)

  • Kim, Gun-Do;Lee, Chang-Sup
    • Journal of the Society of Naval Architects of Korea
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    • v.42 no.2 s.140
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    • pp.113-123
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    • 2005
  • A higher order panel method based on B-spline representation for both the geometry and the solution is developed for the analysis of steady flow around marine propellers. The self-influence functions due to the normal dipole and the source are desingularized through the quadratic transformation, and then shown to be evaluated using conventional numerical quadrature. By selecting a proper order for numerical quadrature, the accuracy of the present method can be increased to the machine limit. The far- and near-field influences are shown to be evaluated based on the same far-field approximation, but the near-field solution requires subdividing the panels into smaller subpanels continuously, which can be effectively implemented due to the B-spline representation of the geometry. A null pressure jump Kutta condition at the trailing edge is found to be effective in stabilizing the solution process and in predicting the correct solution. Numerical experiments indicate that the present method is robust and predicts the pressure distribution on the blade surface, including very close to the tip and trailing edge regions, with far fewer panels than existing low order panel methods.

Ceramic Foams by the Self-Blowing of Polymer (고분자의 자체발포를 이용한 세라믹 다공질체)

  • 백종원;김득중
    • Journal of the Korean Ceramic Society
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    • v.41 no.7
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    • pp.555-559
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    • 2004
  • Ceramic foams were prepared by a self-blowing process of a polysiloxane with A1$_2$O$_3$ as a filler. The release of water and ethanol vapor during the condensation reaction of the polymer triggered the pores in the polymer melt. The size. interconnectivity and shape of the pores in the ceramic foams were strongly dependent on the viscosity of the polymer melt, which could be varied by the content and size oi the filler. When the content of the filler inceased and the size of the filler decreased. the size of the pores were decreased and the thickness between the pores were increased. In the addition, the viscosity of polymer melt increased by the pretreatment at 130$^{\circ}C$ for Ire intermolecular cross linking thereby stabilizing the foam structure. The density and compressive strength of the ceramic foams were affected by the heating rate during the blowing process.

Robert Southey, Colonialism, and the East: The Case of Thalaba the Destroyer (로버트 사우디, 식민주의, 그리고 동양 -『파괴자 탈라바』를 중심으로)

  • Cho, Heejeong
    • Journal of English Language & Literature
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    • v.58 no.5
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    • pp.859-880
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    • 2012
  • This paper aims at analyzing Robert Southey's Thalaba the Destroyer in relation to cultural colonialism of the British Romantic period and investigating the ways in which this text portrays the Other through its literary representation of the East. Especially, this paper attempts to show that the Oriental world constructed in Southey's text reveals the imperial subject's self-conscious awareness of its unstable relation with the unknown Other. For this purpose, this paper attends to the formal aspects of Thalaba the Destroyer, examining the process by which the reader's generic expectations about the "epic" undergo complex revisions and frustrations through reading this text. The epic elements contained in Thalaba the Detroyer include the battle between good and evil and the hero's moral epiphany arising from his struggle against malicious enemies. Yet, Thalaba the Destroyer constantly destabilizes the distinction between self and other by leading the reader to recognize the uncomfortable similarity between the poem's tyrannical figures and imperialistic monarchs in the Western civilization. Thus, when the hero enacts a revolution against despotism, the resistant power points not only to the imagined false kingdom within the text, but to the core of the real Empire that seeks to construct its own "garden" in the global scene. In addition, Southey's "panoramic" description of Oriental objects and stories in his footnotes lacks a framing perspective, erasing and de-stabilizing subject/object distinctions. In these footnotes, he exposes his profound attraction to the culture of "Other" and also conveys his aspiration to transforming Eastern myths and stories into profitable literary texts. Southey's attitude to the East in the footnotes appears to be partially grounded upon the interest of mercantile capitalists of the West, who need to discover potential commodities. Yet, simultaneously, he reveals a sense of moral hesitation about his own desire for the materiality of the East, along with deep anxiety arising from the fear of punishment.