• Title/Summary/Keyword: delta-function

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ON THE CONFORMAL DEFORMATION OVER WARPED PRODUCT MANIFOLDS

  • YOON-TAE JUNG;CHEOL GUEN SHIN
    • The Pure and Applied Mathematics
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    • v.4 no.1
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    • pp.27-33
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    • 1997
  • Let (M = B$\times$f F, g) be an ($n \geq3$ )-dimensional differential manifold with Riemannian metric g. We solve the following elliptic nonlinear partial differential equation (equation omitted). where $\Delta_{g}$ is the Laplacian in the $\Delta$g-metric and ($h(\chi)$) is the scalar curvature of g and ($H(\chi)$) is a function on M.

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ATP and GTP Hydrolytic Function of N-terminally Deleted Annexin I

  • Hyun, Young-Lan;Park, Young-Min;Na, Doe-Sun
    • BMB Reports
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    • v.33 no.4
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    • pp.289-293
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    • 2000
  • Annexin I is a 37 kDa member of the annexin family of calcium-dependent phospholipid binding proteins. Annexin I plays regulatory roles in various cellular processes including cell proliferation and differentiation. Recently we found that annexin I is a heat shock protein (HSP) and displays a chaperone-like function. In this paper we investigated the function of annexin I as an ATPase using 1 to 32 amino acids deleted annexin I (${\Delta}-annexin$ I). ${\Delta}-Annexin$ I hydrolyzed ATP as determined by thin layer chromatography. The ability of ATP hydrolysis was inhibited by ADP, GTP and GDP, but not by the AMP, GMP and cAMP. In view of the ATP hydrolyzing function of HSP, the results support the function of annexin I as a HSP.

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Improved Learning Algorithm with Variable Activating Functions

  • Pak, Ro-Jin
    • Journal of the Korean Data and Information Science Society
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    • v.16 no.4
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    • pp.815-821
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    • 2005
  • Among the various artificial neural networks the backpropagation network (BPN) has become a standard one. One of the components in a neural network is an activating function or a transfer function of which a representative function is a sigmoid. We have discovered that by updating the slope parameter of a sigmoid function simultaneous with the weights could improve performance of a BPN.

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Involvement of Protein Kinase C-δ in Vascular Permeability in Acute Lung Injury

  • Ahn, Jong J.;Jung, Jong P.;Park, Soon E.;Lee, Minhyun;Kwon, Byungsuk;Cho, Hong R.
    • IMMUNE NETWORK
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    • v.15 no.4
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    • pp.206-211
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    • 2015
  • Pulmonary edema is a major cause of mortality due to acute lung injury (ALI). The involvement of protein kinase C-${\delta}$ (PKC-${\delta}$) in ALI has been a controversial topic. Here we investigated PKC-${\delta}$ function in ALI using PKC-${\delta}$ knockout (KO) mice and PKC inhibitors. Our results indicated that although the ability to produce proinflammatory mediators in response to LPS injury in PKC-${\delta}$ KO mice was similar to that of control mice, they showed enhanced recruitment of neutrophils to the lung and more severe pulmonary edema. PKC-${\delta}$ inhibition promoted barrier dysfunction in an endothelial cell layer in vitro, and administration of a PKC-${\delta}$-specific inhibitor significantly increased steady state vascular permeability. A neutrophil transmigration assay indicated that the PKC-${\delta}$ inhibition increased neutrophil transmigration through an endothelial monolayer. This suggests that PKC-${\delta}$ inhibition induces structural changes in endothelial cells, allowing extravasation of proteins and neutrophils.

Determination of Nonstoichiometry$(\delta)$and Phase Stability Region of $(Mg_{0.29}Fe_{0.71})_{3-}\deltaO_4$ by a Coulometric Titration Method (전하적정법에 의한 $(Mg_{0.29}Fe_{0.71})_{3-}\deltaO_4$ 훼라이트의 Nonstoichiometry$(\delta)$와 상안정 영역 결정)

  • 강선호;유한일;강대석;유병두
    • Journal of the Korean Ceramic Society
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    • v.31 no.12
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    • pp.1491-1500
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    • 1994
  • Nonstoichiometry($\delta$) and the phase stability region of a ferrite spinel (Mg0.29Fe0.71)3-$\delta$O4 have been investigated by a coulometric titration method as a function of temperature(T) and oxygen partial pressure(Po2). It has been found that the spinel is thermodynamically stable in the ranges -8.0$\leq$log(PO2/atm)$\leq$-2.4, -7.0$\leq$log(PO2/atm)$\leq$-1.7 respectvely at 100$0^{\circ}C$. The nonstoichiometry extends over the ranges of -0.004$\leq$$\delta$$\leq$0.007, -0.008$\leq$$\delta$$\leq$0.006, -0.033$\leq$$\delta$$\leq$0.004 at 100$0^{\circ}C$, 120$0^{\circ}C$, respectvely. The observed PO2-dependence of $\delta$ suggests that the majority ionic defects are cation interstitials in the low PO2 region and cation vacancies in the high PO2 region.

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Initiation and Propagation Behaviors of Micro-Surface-Fatigue Cracks under In-Plane Tension Fatigue Tests (引張 軸荷重 疲勞 에 의한 微小表面 균열 의 發생 . 成長擧動)

  • 서창민
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.9 no.1
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    • pp.1-9
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    • 1985
  • In-plane tension fatigue tests (R = 0.05) were carried out to investigate the initiation and propagation behaviors of micro-surface-fatigue cracks on smooth surfaces of a mild steel. Also, the investigations of saturated cyclic strain which can be obtained by the fatigue tests have been made via the cyclic strain intensity factor, .DELTA. $K_{\epsilon}$/, for the purpose of unifying two approaches of the study of fatigue; the one approach is based on the fracture mechanics concept and the other on lowcycle fatigue concept. Some of the results are as follows; The growth rate, d(2a)/dN, of small cracks cannot be represented by one straight line as a function of .DELTA.K for various of the nominal stress range, .DELTA..sigma., and is higher than that of a larger through crack. The rearrangement of the d(2a)/dN by .DELTA..epsilon..root..pi.s( = .DELTA. $K_{\epsilon}$/) with the stress range .DELTA..epsilon. in .DELTA.K replaced by .DELTA..epsilon., strain range, gives one straight line of the .DELTA. $K_{\epsilon}$-d(2a)/dN relation for various values of stress range .DELTA.$_{\epsilon}$../.X>../.

Auto-Tuning Method of Learning Rate for Performance Improvement of Backpropagation Algorithm (역전파 알고리즘의 성능개선을 위한 학습율 자동 조정 방식)

  • Kim, Joo-Woong;Jung, Kyung-Kwon;Eom, Ki-Hwan
    • Journal of the Institute of Electronics Engineers of Korea CI
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    • v.39 no.4
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    • pp.19-27
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    • 2002
  • We proposed an auto-tuning method of learning rate for performance improvement of backpropagation algorithm. Proposed method is used a fuzzy logic system for automatic tuning of learning rate. Instead of choosing a fixed learning rate, the fuzzy logic system is used to dynamically adjust learning rate. The inputs of fuzzy logic system are ${\Delta}$ and $\bar{{\Delta}}$, and the output is the learning rate. In order to verify the effectiveness of the proposed method, we performed simulations on a N-parity problem, function approximation, and Arabic numerals classification. The results show that the proposed method has considerably improved the performance compared to the backpropagation, the backpropagation with momentum, and the Jacobs' delta-bar-delta.

Performance Improvement of Backpropagation Algorithm by Automatic Tuning of Learning Rate using Fuzzy Logic System

  • Jung, Kyung-Kwon;Lim, Joong-Kyu;Chung, Sung-Boo;Eom, Ki-Hwan
    • Journal of information and communication convergence engineering
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    • v.1 no.3
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    • pp.157-162
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    • 2003
  • We propose a learning method for improving the performance of the backpropagation algorithm. The proposed method is using a fuzzy logic system for automatic tuning of the learning rate of each weight. Instead of choosing a fixed learning rate, the fuzzy logic system is used to dynamically adjust the learning rate. The inputs of fuzzy logic system are delta and delta bar, and the output of fuzzy logic system is the learning rate. In order to verify the effectiveness of the proposed method, we performed simulations on the XOR problem, character classification, and function approximation. The results show that the proposed method considerably improves the performance compared to the general backpropagation, the backpropagation with momentum, and the Jacobs'delta-bar-delta algorithm.

A Design on Robust Model Following Servo System Using $\delta$--Operator ($\delta$-연산자를 이용한 강인한 모델 추종형 서보 제어 시스템의 구성에 관한연구)

  • Kim, Chung-Tek;Hwang, Hyun-Joon
    • Journal of Institute of Control, Robotics and Systems
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    • v.6 no.2
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    • pp.121-126
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    • 2000
  • In the fast sampling limit the delta operator model tends to the analog system model. This fundamental property of the delta operator model unifies continuous and discrete time control system. In this paper we study robust linear optimal model following servo system in the presence of disturbances and parameter perturbations. A technique to directly design the generalized differential operator based unified control system that covers both differential operator based continuous time and delta operator based discrete time case is presented. The quadratic criterion function for a linear system is used to design the robust unified servo control system The characteristics of the proposed servo system are analysed and simulated to verify the robustness.

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A Design on Robust Model Following Servo System using $\delta$- Operator ($\delta$- 연산자를 이용한 강인한 모델 추종형 서보 시스템의 구성에 관한 연구)

  • Kim, Jeong-Taek;Lee, Hwa-Seok;Park, Seong-Jun;Chu, Yeong-Bae;Hwang, Hyeon-Jun;Lee, Yang-U;Park, Jun-Ho
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.48 no.6
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    • pp.747-752
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    • 1999
  • In the fast sampling limit, the delta operator model tends to the analog system model. This fundamental property of the delta operator model unifies continuous and discrete time control system. In this paper, we study robust linear optimal model following servo system in the presence of disturbances and parameter perturbations. A technique to directly design the generalized differential operator based unified control system that convers both differential operator based continuous time and delta operator based discrete time case is presented. The quadratic criterion function for a linear system is used to design the robust unified servo control. The characteristics of the proposed servo system are analysed and simulated to verify the robustness.

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