• 제목/요약/키워드: logarithm function

검색결과 108건 처리시간 0.021초

컬러 이미지 화질 개선을 위한 Retinex 기반의 로그변환 기법 (Retinex-based Logarithm Transformation Method for Color Image Enhancement)

  • 김동형
    • 한국산학기술학회논문지
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    • 제19권5호
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    • pp.9-16
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    • 2018
  • 광원 자체의 밝기가 낮거나 그림자 등의 이유로 어두운 영역을 포함하는 이미지는 Retinex 기반의 영상화질 개선기법을 통해 주관적 화질을 높일 수 있다. Retinex 이론은 인간의 시각 시스템이 장면을 인식할 때 특정 위치에서의 장면의 밝기를 인식하는 것이 아니라 주변과의 상대적인 밝기를 인식하는 특징을 적용한 방법으로 크게 SSR, MSR, MSRCR의 방법으로 나눌 수 있다. 제안하는 방법은 컬러복원단계를 포함하고 있는 MSRCR에 기반한 방법으로 크게 3단계로 구성되어 있다. 첫 번째 단계에서는 기존의 MSRCR 방법을 적용하고 두 번째 단계에서 MSRCR 출력의 동적 영역을 이미지의 히스토그램분포에 따라 조정한다. 마지막 단계에서는 인간의 시각특성을 고려한 로그변환함수를 이용하여 Retinex 출력 값을 디스플레이 동적영역으로 변환한다. 실험결과 제안하는 알고리즘은 전체적으로 어두운 이미지뿐만 아니라 밝은 영역과 어두운 영역을 모두 포함하는 이미지에서도 주관적 화질을 효과적으로 증가시키는 것을 볼 수 있다. 특히 낮은 밝기를 갖는 이미지의 경우 제안한 알고리즘은 기존의 방법들 보다 높은 성능향상을 보였다.

ON THE RATES OF THE ALMOST SURE CONVERGENCE FOR SELF-NORMALIZED LAW OF THE ITERATED LOGARITHM

  • Pang, Tian-Xiao
    • 대한수학회보
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    • 제48권6호
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    • pp.1137-1146
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    • 2011
  • Let {$X_i$, $i{\geq}1$} be a sequence of i.i.d. nondegenerate random variables which is in the domain of attraction of the normal law with mean zero and possibly infinite variance. Denote $S_n={\sum}_{i=1}^n\;X_i$, $M_n=max_{1{\leq}i{\leq}n}\;{\mid}S_i{\mid}$ and $V_n^2={\sum}_{i=1}^n\;X_i^2$. Then for d > -1, we showed that under some regularity conditions, $$\lim_{{\varepsilon}{\searrow}0}{\varepsilon}^2^{d+1}\sum_{n=1}^{\infty}\frac{(loglogn)^d}{nlogn}I\{M_n/V_n{\geq}\sqrt{2loglogn}({\varepsilon}+{\alpha}_n)\}=\frac{2}{\sqrt{\pi}(1+d)}{\Gamma}(d+3/2)\sum_{k=0}^{\infty}\frac{(-1)^k}{(2k+1)^{2d+2}}\;a.s.$$ holds in this paper, where If g denotes the indicator function.

Studies on the Reaction Mechanism of Azo Dyes with Cetyltrimethylammonium Bromide

  • Kim, Bak-Kwang;Sim, Kyl-Soon;Lee, Wang-Kyu
    • Journal of Pharmaceutical Investigation
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    • 제12권4호
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    • pp.101-111
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    • 1982
  • The effect of salt addition to MO-CTB mixed micelle was studied. The logarithm of cmcs obtained from above experiment is a linear function of the logarithm of the sum of the cmc and the concentration of added salt. In order to investigate the relation of the color change and the structure, the measurement of conductance to the mixed micelle has been carried out. To see the color change and conductance data obtained in the present study, structure A is more probable one to the micelles having the ${\lambda}_{max}$ 376nm.

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CHARACTERIZATION OF POOL-RIFFLE SEQUENCES IN SOLUTE TRANSPORT MODELING OF STREAMS

  • Seo, Il-Won;Yu, Dae-young
    • Water Engineering Research
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    • 제1권3호
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    • pp.171-185
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    • 2000
  • A mathematical model to adequately predict complex mixing characteristics of sorptive polluants in natural streams with pools-and-riffes has been developed. In this model, sorption of pollutants onto the bed sediment as well as mass storage and exchange in the storage zones were incorporated into one-dimensional mass balance equatins. The geometric and hydraulic characteristics of the pool-riffle sequences were properly conceptualized. Simulations with parameters of pool-and-riffle streams better fit the measured data in overall shape and peak concentration than simulations with parameters for uniform channels. The analyses on the characteristics of the storage zone model parameters reveal that a linear relationship between the logrithm of the storage zone volume ratio and a function of the friction factor exists. A linear relatiohship might also be tenatively assumed between the logarithm of the dimensionless mass exchange coefficient and the logarithm of the aspect ratio of the storage zone if some of the high values of the dimensionless mass exchange coefficient collected on the successive bed forms are excluded.

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SYMMETRIC IDENTITIES FOR DEGENERATE q-POLY-BERNOULLI NUMBERS AND POLYNOMIALS

  • JUNG, N.S.;RYOO, C.S.
    • Journal of applied mathematics & informatics
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    • 제36권1_2호
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    • pp.29-38
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    • 2018
  • In this paper, we introduce a degenerate q-poly-Bernoulli numbers and polynomials include q-logarithm function. We derive some relations with this polynomials and the Stirling numbers of second kind and investigate some symmetric identities using special functions that are involving this polynomials.

IDENTITIES INVOLVING THE DEGENERATE GENERALIZED (p, q)-POLY-BERNOULLI NUMBERS AND POLYNOMIALS

  • JUNG, N.S.
    • Journal of applied mathematics & informatics
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    • 제38권5_6호
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    • pp.601-609
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    • 2020
  • In this paper, we introduce degenerate generalized poly-Bernoulli numbers and polynomials with (p, q)-logarithm function. We find some identities that are concerned with the Stirling numbers of second kind and derive symmetric identities by using generalized falling factorial sum.

Superior and Inferior Limits on the Increments of Gaussian Processes

  • Park, Yong-Kab;Hwang, Kyo-Shin;Park, Soon-Kyu
    • Journal of the Korean Statistical Society
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    • 제26권1호
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    • pp.57-74
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    • 1997
  • Csorgo-Revesz type theorems for Wiener process are developed to those for Gaussian process. In particular, some results of superior and inferior limits for the increments of a Gaussian process are differently obtained under mild conditions, via estimating probability inequalities on the suprema of a Gaussian process.

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A LAW OF ITERATED LOGARITHM FOR OCCUPATION TIME BROWNIAN IN ι$_2$

  • Cho, Nhan-Sook
    • 대한수학회논문집
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    • 제14권3호
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    • pp.569-579
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    • 1999
  • We consider a random measure defined by the occupation time of Brownian motion in $l_2$. If it is normalized ${\lambda}^2$log then we show that its cluster set as ${\lambda}{longrightarrow}\infty$ can be represented by Ι-function on $\sigma$-finite measure in $l_2$.

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General Laws of the Iterated Logarithm for Levy Processes

  • Wee, In-Suk;Kim, Yun-Kyong
    • Journal of the Korean Statistical Society
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    • 제17권1호
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    • pp.30-45
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    • 1988
  • Let ${X(t) : 0 \leq t < \infty}$ be a real-valued process with stationary independent increments. In this paper, we obtain necesary and sufficint condition for there to exist a positive, nondecreasing function $\beta(t)$ so that $0 < lim sup $\mid$X(t)$\mid$/\beta(t) < \infty$ a.s. both as t tends to zero and infinity. When no such $\beta(t)$ exists we give a simple integral test for whether $lim sup $\mid$X(t)$\mid$/\beta(t)$ is zero or infinity for a given $\beta(t)$.

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MgO.$P_2O_5$ 유리의 전기전도도에 미치는 수분의 영향 (Effects of Water on the Electrical Conductivity of Magnesium Metaphosphate Glasses)

  • 강은태;박용완
    • 한국세라믹학회지
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    • 제23권4호
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    • pp.85-89
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    • 1986
  • Electrical conductivity have been measured as function of temperature in MgO.$P_2O_5$ glasses containing small amounts of water. Conduction was due to the contribution of $H^+$ and the mobility of protons in the glass increased linearly with increasing its concentration. The conductivity was pro-portional to the square of the proton concentration and the activation energy decreased linerly with increasing logarithm of the proton concentration, And $$\sigma$_0$ and $A_0$ was independent of the proton concentration but not on glass compositions.

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