• Title/Summary/Keyword: time scales

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PRACTICAL ${\phi}_0$-STABILITY FOR IMPULSIVE DYNAMIC SYSTEMS WITH TIME SCALES AND INITIAL TIME DIFFERENCE

  • Chen, Weisong;Han, Zhenlai;Sun, Shurong;Li, Tongxing
    • Journal of applied mathematics & informatics
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    • v.29 no.3_4
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    • pp.891-900
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    • 2011
  • In this paper, we study the impulsive dynamic systems on time scales with initial time difference. By employing cone-valued Lyapunov functions, some comparison theorems and several practical ${\phi}_0$-stability criteria for impulsive system on time scales with initial time difference are obtained.

A Study on Image Pixel Classification Using Directional Scales (방향성 정보 척도를 이용한 영상의 픽셀분류 방법에 관한 연구)

  • 박중순;김수겸
    • Journal of Advanced Marine Engineering and Technology
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    • v.28 no.4
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    • pp.587-592
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    • 2004
  • Pixel classification is one of basic issues of image processing. The general characteristics of the pixels belonging to various classes are discussed and the radical principles of pixel classification are given. At the same time, a pixel classification scheme based on image information scales is proposed. The proposed method is overcome that computation amount become greater and contents easily get turned. And image directional scales has excellent anti-noise performance. In the result of experiment. good efficiency is showed compare with other methods.

CONVERGENCE THEOREMS FOR THE HENSTOCK DELTA INTEGRAL ON TIME SCALES

  • Park, Jae Myung;Kim, Young Kuk;Lee, Deok Ho;Yoon, Ju Han;Lim, Jong Tae
    • Journal of the Chungcheong Mathematical Society
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    • v.26 no.4
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    • pp.879-885
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    • 2013
  • In this paper, we de ne an extension $f^*:[a,b]{\rightarrow}\mathbb{R}$ of function $f^*:[a,b]_{\mathbb{T}}{\rightarrow}\mathbb{R}$ for a time scale ${\mathbb{T}}$ and prove the convergence theorems for the Henstock delta integral on time scales.

Characteristization of Spray Combustion and Turbulent Flame Structures in a Typical Diesel Engine Condition (디젤 엔진 운전 조건에서 분무 연소 과정과 난류 화염 구조 특성에 대한 해석)

  • Lee, Young-J.;Huh, Kang-Y.
    • Journal of the Korean Society of Combustion
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    • v.14 no.3
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    • pp.29-36
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    • 2009
  • Simulation is performed to analyze the characteristics of turbulent spray combustion in a diesel engine condition. An extended Conditional Moment Closure (CMC) model is employed to resolve coupling between chemistry and turbulence. Relevant time and length scales and dimensionless numbers are estimated at the tip and the mid spray region during spray development and combustion. The liquid volume fractions are small enough to support validity of droplets assumed as point sources in two-phase flow. The mean scalar dissipation rates (SDR) are lower than the extinction limit to show flame stability throughout the combustion period. The Kolmogorov scales remain relatively constant, while the integral scales increase with decay of turbulence. The chemical time scale decreases abruptly to a small value as ignition occurs with subsequent heat release. The Da and Ka show opposite trends due to variation in the chemical time scale. More work is in progress to identify the spray combustion regimes.

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Oscillatory Behavior of Linear Neutral Delay Dynamic Equations on Time Scales

  • Saker, Samir H.
    • Kyungpook Mathematical Journal
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    • v.47 no.2
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    • pp.175-190
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    • 2007
  • By employing the Riccati transformation technique some new oscillation criteria for the second-order neutral delay dynamic equation $$(y(t)+r(t)y({\tau}(t)))^{{\Delta}{\Delta}}+p(t)y(\delta(t))=0$$, on a time scale $\mathbb{T}$ are established. Our results as a special case when $\mathbb{T}=\mathbb{R}$ and $\mathbb{T}=\mathbb{N}$ improve some well known oscillation criteria for second order neutral delay differential and difference equations, and when $\mathbb{T}=q^{\mathbb{N}}$, i.e., for second-order $q$-neutral difference equations our results are essentially new and can be applied on different types of time scales. Some examples are considered to illustrate the main results.

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EXISTENCE OF SOLUTION FOR IMPULSIVE FRACTIONAL DYNAMIC EQUATIONS WITH DELAY ON TIME SCALES

  • GAO, ZHI-JUAN;FU, XU-YANG;LI, QIAO-LUAN
    • Journal of applied mathematics & informatics
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    • v.33 no.3_4
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    • pp.275-292
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    • 2015
  • This paper is mainly concerned with the existence of solution for nonlinear impulsive fractional dynamic equations on a special time scale.We introduce the new concept and propositions of fractional q-integral, q-derivative, and α-Lipschitz in the paper. By using a new fixed point theorem, we obtain some new existence results of solutions via some generalized singular Gronwall inequalities on time scales. Further, an interesting example is presented to illustrate the theory.

Application of Seo Dongil's Voice Technique in Patient with Adductor Spasmodic Dysphonia: A Case Study (내전형 경련성 발성장애인에서 서동일 음성치료 기법의 적용 1례)

  • Seo, Dong-Il;Yoo, Jae-Yeon;Jeong, Ok-Ran;Choi, Hong-Shik
    • Speech Sciences
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    • v.9 no.4
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    • pp.39-47
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    • 2002
  • The purpose of this study was to investigate the effects of Seo Dongil's voice technique on voice quality in patient with adductor spasmodic dysphonia. One patient participated in the study. The subject was assessed acoustically (Ave Fo, Ave Int, percent speech time, percent silence time, percent voice time, percent voiceless time) and perceptually (GRBAS scales) in the first and last session. Dr. Speech (version 4.0, Tiger-DRS) was used to compare acoustic parameters of pre-and post-treatment. Seo Dongil's voice technique consisted of relaxation, breathing exercise and phonation exercise. The results were as follows: First, Seo Dongil's voice technique tented to be effective on decreasing voice break and voice stoppage in patient with adductor spasmodic dysphonia. Second, GRBAS scales showed that Seo Dongil's voice technique was effective on improving voice quality of patient with adductor spasmodic dysphonia.

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OSCILLATION OF SECOND-ORDER FUNCTIONAL DYNAMIC EQUATIONS OF EMDEN-FOWLER-TYPE ON TIME SCALES

  • Saker, S.H.
    • Journal of applied mathematics & informatics
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    • v.28 no.5_6
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    • pp.1285-1304
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    • 2010
  • The purpose of this paper is to establish some sufficient conditions for oscillation of solutions of the second-order functional dynamic equation of Emden-Fowler type $\[a(t)x^{\Delta}(t)\]^{\Delta}+p(t)|x^{\gamma}(\tau(t))|\|x^{\Delta}(t)\|^{1-\gamma}$ $sgnx(\tau(t))=0$, $t\;{\geq}\;t_0$, on a time scale $\mathbb{T}$, where ${\gamma}\;{\in}\;(0,\;1]$, a, p and $\tau$ are positive rd-continuous functions defined on $\mathbb{T}$, and $lim_{t{\rightarrow}{\infty}}\;{\tau}(t)\;=\;\infty$. Our results include some previously obtained results for differential equations when $\mathbb{T}=\mathbb{R}$. When $\mathbb{T}=\mathbb{N}$ and $\mathbb{T}=q^{\mathbb{N}_0}=\{q^t\;:\;t\;{\in}\;\mathbb{N}_0\}$ where q > 1, the results are essentially new for difference and q-difference equations and can be applied on different types of time scales. Some examples are worked out to demonstrate the main results.

TIME-DEPENDENT DUST FORMATION IN NOVAE

  • Suh, Kyung-Won
    • Journal of Astronomy and Space Sciences
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    • v.8 no.1
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    • pp.1-10
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    • 1991
  • The dust formation processes in novae are investigated with close attention to recent infrared observations. Using mainly the classical nucleation theory, we have calculated the time scales of dust formation and growth in the environments of novas. Those time scales roughly the typical observations. We have classified the dust-forming novae into three classes according to their explosion properties and the thermodynamic properties of dust grains. Oxygen grains form much later than carbon grains because of their thermodynamic properties. The effect of grain formation to the efficiency of stellar winds to drive the material outward is tested with newly obtained Planck mean values of dust grains.

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