• Title/Summary/Keyword: Global Time

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GLOBAL EXISTENCE OF SOLUTIONS TO THE PREY-PREDATOR SYSTEM WITH A SINGLE CROSS-DIFFUSION

  • Shim, Seong-A
    • Bulletin of the Korean Mathematical Society
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    • v.43 no.2
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    • pp.443-459
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    • 2006
  • The prey-predator system with a single cross-diffusion pressure is known to possess a local solution with the maximal existence time $T\;{\leq}\;{\infty}$. By obtaining the bounds of $W\array_2^1$-norms of the local solution independent of T we establish the global existence of the solution. And the long-time behaviors of the global solution are analyzed when the diffusion rates $d_1\;and\;d_2$ are sufficiently large.

ASYMPTOTIC BEHAVIOR OF STRONG SOLUTIONS TO 2D g-NAVIER-STOKES EQUATIONS

  • Quyet, Dao Trong
    • Communications of the Korean Mathematical Society
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    • v.29 no.4
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    • pp.505-518
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    • 2014
  • Considered here is the first initial boundary value problem for the two-dimensional g-Navier-Stokes equations in bounded domains. We first study the long-time behavior of strong solutions to the problem in term of the existence of a global attractor and global stability of a unique stationary solution. Then we study the long-time finite dimensional approximation of the strong solutions.

Global Asymptotic Stability of a Class of Nonlinear Time-Delay Systems (일종의 비선형 시간 지연 시스템에 대한 광역 점근적 안정성)

  • Choi, Joon-Young
    • Journal of Institute of Control, Robotics and Systems
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    • v.13 no.3
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    • pp.187-191
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    • 2007
  • We analyze the stability property of a class of nonlinear time-delay systems. We show that the state variable is bounded both below and above, and the lower and upper bounds of the state are obtained in terms of a system parameter by using the comparison lemma. We establish a time-delay independent sufficient condition for the global asymptotic stability by employing a Lyapunov-Krasovskii functional obtained from a change of the state variable. The simulation results illustrate the validity of the sufficient condition for the global asymptotic stability.

A Stability Analysis Scheme for a Class of First-Order Nonlinear Time-Delay Systems (일종의 일차 비선형 시간 지연 시스템을 위한 안정성 분석 방법)

  • Choi, Joon-Young
    • Journal of Institute of Control, Robotics and Systems
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    • v.14 no.6
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    • pp.554-557
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    • 2008
  • We analyze the stability property of a class of nonlinear time-delay systems with time-varying delays. We present a time-delay independent sufficient condition for the global asymptotic stability. In order to prove the sufficient condition, we exploit the inherent property of the considered systems instead of applying the Krasovskii or Razumikhin stability theory that may cause the mathematical difficulty of analysis. We prove the sufficient condition by constructing two sequences that represent the lower and upper bound variations of system state in time, and showing the two sequences converge to an identical point, which is the equilibrium point of the system. The simulation results illustrate the validity of the sufficient condition for the global asymptotic stability.

COMPARISON OF GLOBAL SEA SURFACE TEMPERATURE PRODUCTS

  • Kubota, Masahisa.;Iwasaki, Shinzuke
    • Proceedings of the KSRS Conference
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    • v.2
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    • pp.993-996
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    • 2006
  • NOAA operational bulk SST product (Reynolds et al, 2002) is very popular global SST data sets and is extensively used for various studies. However, the original time resolution is weekly and relatively large. On the other hand, there exist many new global SST data sets at present. In this study, we compare many global SST data sets including NOAA operational bulk SST product, CAOS OI SST product, Microwave Optimum Interpolation (MWOI) SST, Real Time Global (RTG) SST and JMA merged satellite and in situ Global Daily (MGD) SST.

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Empirical Prediction Models of 1-min Rain Rate Distribution for Various Integration Time

  • Jung, Myoung-Won;Han, Il-Tak;Choi, Moon-Young;Lee, Joo-Hwan;Pack, Jeong-Ki
    • Journal of electromagnetic engineering and science
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    • v.8 no.2
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    • pp.84-89
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    • 2008
  • In a wireless channel above microwave frequency, rain attenuation is very important. In order to predict rain attenuation, 1-min. rain rate distribution is required. This paper discusses appropriate conversion methods to estimate 1-minute rain rate from that of other integration time. Based on the measurement data filed in ITU-R WP3J including ETRI data for 6 consecutive years, distributions of rain rate with 1-, 5-, 10-, 20-, 30-minute integration time were analyzed, both on the global and regional basis, and the parametric relationship between the statistical characteristics of 1-minute and other measurement data were investigated to deduce the conversion methods. It is shown that the global model works good with good accuracy for 5-, 10-, 20-min integration time, and the global model is also applicable globally with good accuracy for 5-, 10-, 20-min integration time. The global conversion model was adopted last year as an ITU-R document for new recommendation. The regional conversion model would also be very useful for locations of similar climatic zone.

A Study on the GSCM Strategy and Business Performance - Focus on DOOLEE VISION Case - (GSCM전략과 사업성과에 관한 연구 -두리비전 사례를 중심으로-)

  • Kim, Chang-Bong
    • International Commerce and Information Review
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    • v.8 no.1
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    • pp.325-336
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    • 2006
  • This paper examines the global supply chain management strategy and business performance of Doolee Vision Co. Ltd.. Based on the analysis of eighty-seven cases, the following results were found. First, it was found that just-in-time of GSCM strategy of firm have a positive influences on the business performance in transformation sector. Second, just-in-time of GSCM strategy of firm have a positive influences on the business performance in custody sector. Third, just-in-time of GSCM strategy of firm have a positive influences on the business performance in order response and support sector. Forth, just-in-time of GSCM strategy of firm have a positive influences on the business performance in customs sector. Fifth, just-in-time of GSCM strategy of firm have a positive influences on the business performance in customer service sector. However, several limitations, such as measurement for intra-industry homogeneity, measurement for flexibility of global supply chain management strategy, and measurement for business performance of global supply chain management, that make the preceding conclusions be considered preliminary.

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The Effect of Yukilsunki-tang extracts on Global Cerebral Ischemia in mice (육일순기탕(六一順氣湯) 추출물(抽出物)이 생쥐의 전뇌허혈(全腦虛血)에 미치는 영향(影響))

  • Jeong, Sung-Hyun;Shin, Gil-Cho;Lee, Won-Chul
    • The Journal of Dong Guk Oriental Medicine
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    • v.7 no.2
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    • pp.149-154
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    • 1999
  • The effect of Yukilsunki-tang extracts on global cerebral ischemia were investigated in this study. The multiple parameters of global cerebral ischemia assessed in mice included the duration of KCN-induced(1.8mg/kg i.v.) coma, the survival time of KCN-induced(3.0mg/kg i.v.) coma, the survival time exposed to hypoxia induced by vacuum pump. In the case of global cerebral ischemia International Cancer Research mice were used and divided into two groups at random Group A, normal control, was treated after oral administration of normal saline. Group B, experimental control, was treated after oral administration of 13.2mg/20g of Yukilsunki-tang extracts. Each treatment was KCN-induced(1.8mg/kg i.v.) coma, KCN-induced(3.0mg/kg i.v.) coma and exposure to hypoxia induced by vacuum pump. The results were obtained as follows ; In global cerebral ischemia, Yukilsunki-tang extracts significantly prolonged the duration of KCN-induced(1.8mg/kg i.v.) coma, the survival time of KCN-induced(3.0mg/kg i.v.) coma and the survival time of exposure to hypoxia induced by vacuum pump in mice. Conclusion Yukisunki-tang extracts had a significant effect on Global cerebral ischemia.

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Time Series Evaluation of Visual Fatigue and Depth Sensation Using a Stereoscopic Display

  • Kim, Sang-Hyun;Kishi, Shinsuke;Kawai, Takashi;Hatada, Toyohiko
    • Journal of Information Display
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    • v.10 no.4
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    • pp.188-194
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    • 2009
  • Conventional stereoscopic (3D) displays using binocular parallax generate unnatural conflicts between convergence and accommodation. These conflicts can affect the observer's ability to fuse binocular images and may cause visual fatigue. In this study, time series changes in visual fatigue and depth sensation when viewing stereoscopic images with changing parallax were examined. In particular, the physiological changes, including the subjective symptoms of visual fatigue, when viewing five parallax conditions, were examined. Then a comparative analysis of the 2D and 3D conditions was performed based on the visual function. To obtain data regarding the visual function, the time series changes in the spontaneous-blinking rate before and during the viewing of 3D images were measured. The time series change results suggest that 2D and 3D images cause significantly different types of visual fatigue over the range of binocular disparity.

NEW CONDITIONS ON EXISTENCE AND GLOBAL ASYMPTOTIC STABILITY OF PERIODIC SOLUTIONS FOR BAM NEURAL NETWORKS WITH TIME-VARYING DELAYS

  • Zhang, Zhengqiu;Zhou, Zheng
    • Journal of the Korean Mathematical Society
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    • v.48 no.2
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    • pp.223-240
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    • 2011
  • In this paper, the problem on periodic solutions of the bidirectional associative memory neural networks with both periodic coefficients and periodic time-varying delays is discussed. By using degree theory, inequality technique and Lyapunov functional, we establish the existence, uniqueness, and global asymptotic stability of a periodic solution. The obtained results of stability are less restrictive than previously known criteria, and the hypotheses for the boundedness and monotonicity on the activation functions are removed.