• Title/Summary/Keyword: Kappa distribution

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Enhanced spontaneous emissions from suprathermal populations in Kappa distributed plasmas

  • Kim, Sunjung
    • The Bulletin of The Korean Astronomical Society
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    • v.43 no.1
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    • pp.56.3-56.3
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    • 2018
  • The present study formulates the theory of spontaneously emitted electromagnetic fluctuations in magnetized plasmas containing particles with an anisotropic suparthermal (bi-Kappa) velocity distribution function. The formalism is general applying for an arbitrary wave vector orientation and wave polarization, and for any wave-frequency range. As specific applications, the high-frequency electromagnetic fluctuations emitted in the upper-hybrid and multiple harmonic electron cyclotron frequency range are evaluated. The fluctuations for low-frequency are also applied, which include the kinetic $Alfv\acute{e}n$, fast magnetosonic/whistler, kinetic slow mode, ion Bernstein cyclotron modes, and higher-order modes. The model predictions are confirmed by a comparison with particle-in-cell simulations. The study describes how energetic particles described by kappa velocity distribution functions influence the spectrum of high and low frequency fluctuations in magnetized plasmas. The new formalism provides quantitative analysis of naturally occurring electromagnetic fluctuations, and contribute to an understanding of the electromagnetic fluctuations observed in space plasmas, where kappa-distributed particles are ubiquitous.

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Bayesian Estimation of the Two-Parameter Kappa Distribution

  • Oh, Mi-Ra;Kim, Sun-Worl;Park, Jeong-Soo;Son, Young-Sook
    • Communications for Statistical Applications and Methods
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    • v.14 no.2
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    • pp.355-363
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    • 2007
  • In this paper a Bayesian estimation of the two-parameter kappa distribution was discussed under the noninformative prior. The Bayesian estimators are obtained by the Gibbs sampling. The generation of the shape parameter and scale parameter in the Gibbs sampler is implemented using the adaptive rejection Metropolis sampling algorithm of Gilks et al. (1995). A Monte Carlo study showed that the Bayesian estimators proposed outperform other estimators in the sense of mean squared error.

Comparison of Parameter Estimation Methods in A Kappa Distribution

  • Jeong, Bo-Yoon;Park, Jeong-Soo
    • 한국데이터정보과학회:학술대회논문집
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    • 2006.04a
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    • pp.163-169
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    • 2006
  • This paper deals with the comparison of parameter estimation methods in a 3-parameter Kappa distribution which is sometimes used in flood frequency analysis. The method of moment estimation(MME), L-moment estimation(L-ME), and maximum likelihood estimation(MLE) are applied to estimate three parameters. The performance of these methods are compared by Monte-carlo simulations. Especially for computing MME and L-ME, ike dimensional nonlinear equations are simplied to one dimensional equation which is calculated by the Newton-Raphson iteration under constraint. Based on the criterion of the mean squared error, the L-ME is recommended to use for small sample size $(n\leq100)$ while MLE is good for large sample size.

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Wall Heat Conduction and Convection Heat Transfer from a Cylinder in Cross Flow (원형 실린더 주위의 전도-대류 열전달)

  • 이상봉;이억수;김시영
    • Journal of Ocean Engineering and Technology
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    • v.15 no.3
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    • pp.1-8
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    • 2001
  • With uniform heat generation within the wall of the cylinder placed in a cross flow, heat flows by conduction in the circumferential direction due to the asymmetric nature of the fluid flow around the perimeter of the cylinder. The circumferential heat flow affects the wall temperature distribution to such an extent that in some cases significantly different results may be obtained for geometrically similar surfaces. In the present investigation, the effects of circumferential wall heat conduction on local convective heat transfer is investigated for the case of forced convection around horizontal cylinder in cross flow of air. Two-dimensional temperature distribution $T_w$/(${\gamma}$,${\theta}$) is presented through the numerical analysis. The one-dimensional and two-dimensional solutions are in good agreement with experimental results of local heat transfer coefficients.

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Distribution of the Equivalent Rectangular Stress Block for High-Strength Polymer Concrete Beams (고강도 폴리머 콘크리트보의 등가직사각형 응력분포)

  • 김관호;연규석;김남길;조규우
    • Proceedings of the Korea Concrete Institute Conference
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    • 2001.05a
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    • pp.915-920
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    • 2001
  • This study was conducted to analysis the distribution of the rectangular stress block for high-strength polymer concrete beam. C-shaped specimens were produced and tested to compute parameters of the rectangular stress block. They were $\kappa_{1}$ = 0.73, $\kappa_{3}$ = 0.94 and $\gamma$= 0.845, respectively. Experimental value of flexural strength of beam was same to be compared with theoretical value. But there is desirable to need many experimental data in order to exact design of polymer concrete structure.

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The Effects of Bangpungtongsungsan Extract to the Skin Damage on Mice Model after Atopic Dermatitis Elicitation (방풍통성산(防風通聖散)이 아토피 피부염을 유발한 동물모델의 피부 손상에 미치는 영향)

  • Son, Jung-Min;Hong, Seung-Ug
    • The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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    • v.20 no.1 s.32
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    • pp.99-114
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    • 2007
  • Objectives : Atopic dermatitis has a close relationship with damage of skin barrier function. To investigate the effects of Bangpungtongsungsan(BT) extract to the skin damage on mice model after atopic dermatitis elicitation, this study was done through forcing injury to mice's skin. Methods : The BALB/c mice were distributed into three groups: control(CON) group, atopic dermatitis(AD)-elicited group, Bangpungtongsungsan(BT)-treated group. AD-elicited and BT-treated group were caused AD according to the method of Christophers E., Mrowietz and Minehiro. The BT extract was administered for 48 hours to BT-treated group. We observed changes of external dermal formation, eosinophils in vasculature, lipid formation in stratum corneum, distribution of ceramide, distribution of capillary, $I{\kappa}B$ kinase(IKK) and induce nitric oxide synthase(iNOS) mRNA expression. We used the statistical methods of student t-test(p<0.05). Results : After dispensing BT extract into the AD-elicited group, the number of eosinophil as an atopic index in mice noticeably decreased and dermal injury decreased. Also the decrease of hyperplasia, degranulated mast cells, angiogenesis and substance P were shown. The lipid lamellae, lipid protect formation, were repaired and the distribution of ceramide which inhibit protein kinase C(PKC) activation increased, and the PKC caused inhibition of nuclear $factor(NF)-{\kappa}B$ activation. As a result of inhibition of $NF-{\kappa}B$ activation, iNOS production were inhibited and apoptotic cell were increased. Moreover the decrease of IKK and iNOS mRNA expression in BT-treated RAW 264.7 cell were noted. Conclusion : BT mitigated skin damage on mice model after atopic dermatitis elicitation through recovering skin barrier function and inhibiting nuclear $factor(NF)-{\kappa}B$ activation.

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The Effect of Seasoning on the Distribution of Nutrient Intakes by a Food-Frequency Questionnaire in a Rural Area (한 농촌 지역에서 식품섭취빈도조사로 측정된 영양소 섭취 분포에 유지류와 양념류가 미치는 영향)

  • Yun, Sung-Ha;Choi, Bo-Youl;Kim, Mi-Kyung
    • Journal of Nutrition and Health
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    • v.42 no.3
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    • pp.246-255
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    • 2009
  • The development of food frequency questionnaire (FFQ) is based on food use and/or dish use. Regardless of potential effect of oils and seasonings on chronic diseases, most of food-based FFQs do not include oils and seasonings in calculation of nutrient intake. This study examined the effect of added (seasoning) oils and seasonings on the distribution of subjects by relative nutrient intake using a dish-based FFQ. The subjects were 1,303 persons (men 478, women 825) aged over 20 years old, who completed FFQ composed of 121 items. Three types of daily nutrient intake were calculated; 1) total nutrient intake with oils and seasonings, 2) nutrient intake without oils, and 3) nutrient intake without oils and seasonings. The correlation and agreement of classification of subjects by relative nutrient intake were examined. All analyses were performed using absolute nutrient intakes and total energy-adjusted nutrient intakes by residual method. Comparing total nutrient intake with the nutrient intake without oils, energy, vegetable fat and vitamin E intake were significantly decreased and kappa values were 0.95 (${\kappa}{\omega}$ = 0.98), 0.64 (${\kappa}{\omega}$ = 0.81), and 0.59 (${\kappa}{\omega}$ = 0.79), respectively. Comparing total nutrient intake with the nutrient intake without oils and seasonings, most of nutrients intake except animal fat, animal protein, retinol and cholesterol were significantly decreased, and kappa values of vegetable fat (${\kappa}$ = 0.64, ${\kappa}{\omega}$ = 0.81), vitamin E (${\kappa}$ = 0.59, ${\kappa}{\omega}$ = 0.79) and sodium (${\kappa}$ = 0.61, ${\kappa}{\omega}$ = 0.80) were under 0.80. After total energy was adjusted, agreement was lower than before total energy adjustment. Excluding oils and seasonings to assess nutrient intake underestimated vegetable fat, vitamin E and sodium intake and affected the distribution of subjects by their relative nutrient intake. Therefore, we suggest that research focused on these nutrients need to be cautious about the interpretation of the results.

NATURAL CONVECTION BETWEEN TWO HORIZONTAL PLATES WITH SMALL MAGNITUDE NON-UNIFORM TEMPERATURE IN THE LOWER PLATE : Pr=0.7 (아래 평판이 미소한 불균일 온도를 갖는 두 수평 평판 사이에서의 자연 대류 : Pr=0.7)

  • Yoo, Joo-Sik
    • Journal of computational fluids engineering
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    • v.18 no.2
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    • pp.35-40
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    • 2013
  • Natural convection of air with Pr=0.7 between two horizontal plates with small magnitude non-uniform temperature distribution[${\in}{\Delta}Tsin({\kappa}X/H)$, H : gap width, X : horizontal coordinate] in the lower plate is numerically(${\in}=0.01$) investigated. In the conduction-dominated regime with $Ra{\leq}1700$, two upright cells are formed over one wave length($2{\pi}/{\kappa}$). For small wave number, the flow becomes unstable with increase of Rayleigh number, and multicellular convection occurs above a critical Rayleigh number. The flow patterns are classified by the number of eddies over one wave length. When ${\kappa}=1$, a transition of $2{\rightarrow}4{\rightarrow}6$ eddy flow occurs with increase of Rayleigh number, and no hysteresis phenomenon is observed. Dual and triple solutions are found for ${\kappa}=1$, and transitions of $10{\rightarrow}8$, $8{\rightarrow}6$, $6{\rightarrow}4{\rightarrow}2$ eddy flow occur with decrease of Rayleigh number.

The Comparative Study for NHPP Software Reliability Growth Model Based on Non-linear Intensity Function (비선형 강도함수를 가진 NHPP 소프트웨어 신뢰성장 모형에 관한 비교 연구)

  • Kim, Hee-Cheul
    • Convergence Security Journal
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    • v.7 no.2
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    • pp.1-8
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    • 2007
  • Finite failure NHPP models presented in the literature exhibit either constant, monotonic increasing or monotonic decreasing failure occurrence rates per fault (intensity function). In this paper, intensity function of Goel-Okumoto model was reviewed, proposes Kappa (2) and the Burr distribution, which maked out efficiency application for software reliability. Algorithm to estimate the parameters used to maximum likelihood estimator and bisection method. For model determination and selection, explored goodness of fit (the error sum of squares) The methodology developed in this paper is exemplified with a software reliability real data set introduced by NTDS (Naval Tactical Data System)

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Effect of $\kappa$-Carrageenan and Guar Gum as a Substitute for Inorganic Polyphosphate on Pork Sausages

  • Park, Ki-Soo;Choi, Yang-Il;Lee, Sang-Hwa;Kim, Chong-Hee;Auh, Joong-Hyuck
    • Food Science and Biotechnology
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    • v.17 no.4
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    • pp.794-798
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    • 2008
  • Guar gum and $\kappa$-carrageenan were investigated as a substitutes for phosphate in pork meat processing. Emulsion-type pork sausages were prepared in which 0.5% phosphate was used for the control, and either $\kappa$-carrageenan or guar gum were added at levels of 0.1 or 0.5% for comparison. The hydrocolloid compounds significantly enhanced water holding capacity and cooking loss. However, hardness, cohesiveness, and chewiness were not well-maintained when compared to the control; this was attributable to the altered water distribution as well as enhanced water holding capacity of the sausages by the addition of $\kappa$-carrageenan and guar gum. Furthermore, the phosphate-free sausages had similar storage stability as the phosphate-added sausage. Overall, the results suggest that $\kappa$-carrageenan or guar gum can be used in place of phosphate in conventional processing to successfully prepare phosphate-tree pork sausages.