• Title/Summary/Keyword: $k-{\varepsilon}$

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The Role of Linguistic Knowledge in the Perception of English Stops after /s/

  • Kim, Dae-Won
    • Speech Sciences
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    • v.3
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    • pp.71-82
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    • 1998
  • Five sets of nonsense acoustical stimuli {$[sp{\varepsilon},st{\varepsilon},sk{\varepsilon}],\;[p{\varepsilon},t{\varepsilon},k{\varepsilon}],\;[sb{\varepsilon},sd{\varepsilon},sg{\varepsilon}],\;[b{\varepsilon},d{\varepsilon},g{\varepsilon}],\;['{\varepsilon}b{\varepsilon},'{\varepsilon}d{\varepsilon},'{\varepsilon}g{\varepsilon}]$} were presented for identification of English stops to native speakers of English, Chinese, and Korean. The English speakers perceived stops after /s/ as /p, t, k/; in other contexts as /b, d, g/. In the languages where other distinctions exist, however, the evaluation was different. The results suggest that in English the cue for stops after /s/ was syllable structure constraint: After initial /s/ always /p, t, k/ follow; the cue for the initial stops was aspiration. On the basis of the results, it was concluded that in English we should classify the unaspirated voiceless stops in initial /s/-stop clusters into the phoneme where [$p^{h},t^{h},k^{h}$] are in, and that perception is not only language specific but also context specific.

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The Numerical Analysis on In-cylinder Flow Fields of an Axisymmetric Engine Using $K-{\varepsilon}-{\tau}$ Turbulence Model ($K-{\varepsilon}-{\tau}$ 난류모델을 이용한 축대칭 엔진 실린더내 유동장의 수치해석)

  • 최재성
    • Journal of Advanced Marine Engineering and Technology
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    • v.23 no.5
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    • pp.711-718
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    • 1999
  • Current turbulence models including modified $K-{\varepsilon}-{\tau}$ turbulence model do not predict compression effect on turbulence accurately in an internal combustion engine. The $K-{\varepsilon}-{\tau}$ turbulence model was suggested to improve the predictability of compression effect by We et al. In this paper a numeri-cal study was performed to clarify the applicability of the $K-{\varepsilon}-{\tau}$ turbulenc model to the calculation of the in-cylinder flow of an axisymmetric engine. THe results using $K-{\varepsilon}-{\tau}$ turbulence model are compared to those from the modified $K-{\varepsilon}-{\tau}$ turbulence model and experimental data. The mean veloc-ity and rms velocity profiles using $K-{\varepsilon}-{\tau}$ turbulence model showed a better agreement with an experimental data than those of modifid $K-{\varepsilon}-e$ turbulence model.

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Flow Analysis with a Port/Valve Assembly and Cylinder Using a RNG k-$\varepsilon$ Model (RNG k-$\varepsilon$모델을 이용한 포트/밸브계 및 실린더내의 유동해석)

  • 양희천
    • Journal of Advanced Marine Engineering and Technology
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    • v.22 no.4
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    • pp.436-444
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    • 1998
  • Applicability of the RNG k-$\varepsilon$ model to the analysis of unsteady axisymmetric turbulent flow of a reciprocating engine including port/valve assembly is studied numerically. The governing equations based on non-orthogonal including port/valve assembly is studied numerically. The governing equations based on a non-orthogonal coordinate formulation with Cartesian velocity components are used and discretised by the finite volume method with non-staggered variable arrangements. The predicted results using the RNG k-$\varepsilon$ model of the unsteady axisymmetric turbulent flow within a cylinder of reciprocating model engine including port/valve assembly are compared to these from the modified k-$\varepsilon$ model and experimental data. Using the RNG k-$\varepsilon$ model seems the have some potential for the simulations of the unsteady turbulent flow within a port/valve-cylinder assembly over the modified k-$\varepsilon$model.

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A GENERALIZATION OF FUZZY SUBSEMIGROUPS IN SEMIGROUPS

  • Kang, Mee Kwang;Ban, Hee Young;Yun, Sang Wook
    • The Pure and Applied Mathematics
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    • v.20 no.2
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    • pp.117-127
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    • 2013
  • As a generalization of fuzzy subsemigroups, the notion of ${\varepsilon}$-generalized fuzzy subsemigroups is introduced, and several properties are investigated. A condition for an ${\varepsilon}$-generalized fuzzy subsemigroup to be a fuzzy subsemigroup is considered. Characterizations of ${\varepsilon}$-generalized fuzzy subsemigroups are established, and we show that the intersection of two ${\varepsilon}$-generalized fuzzy subsemigroups is also an ${\varepsilon}$-generalized fuzzy subsemigroup. A condition for an ${\varepsilon}$-generalized fuzzy subsemigroup to be ${\varepsilon}$-fuzzy idempotent is discussed. Using a given ${\varepsilon}$-generalized fuzzy subsemigroup, a new ${\varepsilon}$-generalized fuzzy subsemigroup is constructed. Finally, the fuzzy extension of an ${\varepsilon}$-generalized fuzzy subsemigroup is considered.

A Study on the Statistical Evaluation of Apolipoprotein E Genotype and Alzheimer's Disease (Apolipoprotein E 유전자형과 알츠하이머형 치매의 통계적인 고찰)

  • Jung, An Na;Lee, Yoen Ju;Choi, Sam Kyu;Park, Jung Oh;Woo, Myoung Soo;Yu, Kyong Nae
    • Korean Journal of Clinical Laboratory Science
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    • v.36 no.2
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    • pp.110-114
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    • 2004
  • Apolipoprotein E is the major lipid-carrier protein in the brain, and several studies provided evidence that apolipoprotein E(ApoE) epsilon4 allele can be considered a genetic risk factor for Alzheimer's disease(AD). Inheritance of the APOE gene has three alleles: ${\varepsilon}2$, ${\varepsilon}3$ and ${\varepsilon}4$. There are six possible genotypes: ${\varepsilon}2/{\varepsilon}2$, ${\varepsilon}3/{\varepsilon}3$, ${\varepsilon}4/{\varepsilon}4$, ${\varepsilon}2/{\varepsilon}3$, ${\varepsilon}2/{\varepsilon}4$, ${\varepsilon}3/{\varepsilon}4$. AD is characterized by a progressive loss of function and death of nerve cells in several areas of the brain. The ${\varepsilon}4$ allele is associated with a risk for developing AD. People with the ${\varepsilon}4/{\varepsilon}4$ genotype have the highest risk, but people with the ${\varepsilon}2/{\varepsilon}4$ or ${\varepsilon}3/{\varepsilon}4$ genotypes are also likely to develop the disease. 64.3% of people carry the is ${\varepsilon}3/{\varepsilon}3$ genotype, 22.1% carry the second ${\varepsilon}3/{\varepsilon}4$ genotype but, ${\varepsilon}2/{\varepsilon}2$ genotype is not usually found of people carry the 3.6% is ${\varepsilon}4/{\varepsilon}4$ genotype in a total of a test group of 140 people. The ratio of ${\varepsilon}4/{\varepsilon}4$ genotype related directly with AD is less than the ${\varepsilon}3/{\varepsilon}3$ genotype, but the ${\varepsilon}2/{\varepsilon}4$ and ${\varepsilon}3/{\varepsilon}4$ genotype ratio of indirect AD risk is 25.7% in the group of people, regardless. Thus, we have referred to the benefit from the treatment of AD through apoE genotype diagnosis.

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Dependence of Damping Capacity on Volume Fractions of Thermal and Deformation-induced ${\varepsilon}$ Martensites in an Fe-Mn Alloy (Fe-Mn 합금에서 열적 ${\varepsilon}$ 마르텐사이트와 변형유기 ${\varepsilon}$ 마르텐사이트 부피분율에 대한 진동감쇠능의 의존성)

  • Jun, Joong-Hwan;Hong, Kwon-Pyo;Choi, Chong-Sool
    • Journal of the Korean Society for Heat Treatment
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    • v.15 no.6
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    • pp.272-278
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    • 2002
  • The changes in damping capacity with volume fractions of thermal and deformation-induced ${\varepsilon}$ martensites were compared and analyzed in an Fe-23%-Mn alloy. The volume fraction of thermal ${\varepsilon}$ martensite increased with decreasing cooling temperature, whereas that of deformation-induced ${\varepsilon}$ martensite increased steeply up to 10%- of cold rolling and nearly saturated in further cold rolling. In the case of thermal ${\varepsilon}$ martensite, the damping capacity increased linearly with the increase in ${\varepsilon}$ martensite content. For the deformation-induced ${\varepsilon}$ martensite, however, the damping capacity increased continuously up to 70%- of ${\varepsilon}$ martensite, over which it decreased suddenly. TEM microstructures showed that the deterioration of damping capacity above 70%- of deformation-induced ${\varepsilon}$ martensite is ascribed to the introduction of perfect dislocations, which play a important role in inhibiting the movement of damping sources such as stacking fault boundaries inside ${\varepsilon}$ martensite, ${\varepsilon}$ martensite variant boundaries and ${\gamma}/{\varepsilon}$ interfaces.

Numerical Simulations of Open-Channel Flow using Non-Linear k-$\varepsilon$ Turbulence Model (비선형 k-$\varepsilon$ 난류모형을 이용한 개수로 흐름 해석)

  • Choi, Seong-Wook;Kang, Hyeong-Sik;Choi, Sung-Uk
    • Proceedings of the Korea Water Resources Association Conference
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    • 2012.05a
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    • pp.566-570
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    • 2012
  • 본 연구에서는 비선형 k-$\varepsilon$ 모형을 이용하여 직사각형 개수로에서 평균흐름과 난류구조를 모의하였다. 표준 k-$\varepsilon$ 난류모형은 난류의 등방성을 가정하여 국부적 평형상태에서 계산하기 때문에 유선에 따른 레이놀즈 응력의 변형이 큰 경우나 이방성이 강한 경우 이를 계산하지 못한다. 이를 보완하기 위하여 제시된 것이 비선형 k-$\varepsilon$ 난류모형이다. 본 연구에서는 표준 k-$\varepsilon$ 모형과 비선형 k-$\varepsilon$ 모형에 의한 모의결과를 비교하였다. 난류모형을 검증하기 위하여 직사각형 개수로에 흐름을 완전 발달된 등류로 가정하여 해석하였다. 지배방정식을 해석하기 위해 Patankar와 Spalding (1972)이 제시한 SIMPLER 알고리즘을 사용하였고 유한체적법을 이용하여 이산화하고 엇갈린 격자체계를 사용하여 계산에서 발생하는 과도한 진동을 줄였다. 또한 차분기법은 Patankar (1980)가 제시한 Power-law 기법을 채택하였으며 경계조건으로 2층 벽법칙 모형과 Hossain과 Rodi (1993)의 모형을 이용하였다. 두 모형의 적용성을 검증하기 위하여 실측자료를 이용하여 비교하였고 그 결과 비선형 k-$\varepsilon$ 모형이 표준 k-$\varepsilon$ 모형에 비해 좀 더 실측지에 가깝게 모의하는 것을 볼 수 있었다.

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Measurement of Volume Fraction of ${\varepsilon}$ Martensite using Specific Volume Difference in Fe-Mn Based Alloys (Fe-Mn 계 합금에서 비부피 차를 이용한 ${\varepsilon}$ 마르텐사이트의 부피분율 측정)

  • Jee, K.K.;Han, J.H.;Jang, W.Y.
    • Journal of the Korean Society for Heat Treatment
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    • v.16 no.4
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    • pp.211-215
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    • 2003
  • In this work, a new way of measuring the volume fraction of e martensite in Fe-based alloys has been proposed. Since the specific volume of ${\varepsilon}$ martensite, depending on alloy composition, is smaller than that of austenite i.e ${\gamma}$ phase, volume expansion takes place during ${\varepsilon}{\rightarrow}{\gamma}$ reverse transformation. As the amount of the volume expansion is proportional to the product of specific volume difference times the volume fraction of ${\varepsilon}$ martensite, the volume fraction of ${\varepsilon}$ martensite can be calculated by measuring the volume expansion and the specific volume difference. Such a relationship was confirmed in Fe-21Mn and Fe-32Mn-6Si alloys which undergo ${\gamma}{\rightarrow}{\varepsilon}$ martensitic transformation on cooling and by cold rolling, respectively. It was also found that the former has isotropic ${\varepsilon}$ martensite while the latter has anisotropic ${\varepsilon}$ martensite.

Prediction of Turbulent Flows with Separation and Swirl Using the RNG K-$\varepsilon$ Turbulence Model (RNG k-$\varepsilon$ 난류모델을 이용한 유동박리 및 선회를 가지는 난류유동의 예측)

  • 김성구;오군섭;김용모;이창식
    • Transactions of the Korean Society of Automotive Engineers
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    • v.4 no.5
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    • pp.119-129
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    • 1996
  • This study is concerned with the critical evaluation of predicative capability of a k-$\varepsilon$ turbulence model using the Renormalization Group(RNG) theory. The present numerical model for solution of the Navier-Stokes System is based on the modified PISO algorithms. Computations have been performed with the RNG-based K-$\varepsilon$ model for the two-dimensional flow over a backward-facing step, a confined coaxial jet, and a swirling flow in a swirl combustor. Numerical results are compared with experimental data in terms of mean flow velocities, turbulent kinetic energy, and turbulent stresses. Numerical results clearly indicate that the RNG-based K-$\varepsilon$ turbulence model shows a significant improvement over a standard K-$\varepsilon$ model in predicting the turbulent flows with flow separation and swirl.

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Numerical Computations of Turbulent Flow in a $90^{\circ}$ Curved Duct Using a Modified Extended $k-\varepsilon$ Turbulence Model (수정된 Extendel $k-\varepsilon$ 난류모델을 사용한 $90^{\circ}$곡관 내의 난류유동에 관한 수치해석적 연구)

  • 정수진;김태훈;조진호
    • Transactions of the Korean Society of Automotive Engineers
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    • v.4 no.3
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    • pp.139-146
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    • 1996
  • An extended $k-\varepsilon$ tuebulence model modified by considering the streamline curvature effect and standard $k-\varepsilon$ turbulence model have been applied for three dimensional analysis of turbulece flow in a $90^{\circ}$ curved duct. By comparision of the results with the experimental data, the modified extended $k-\varepsilon$ model gave closer agreement with experimental data than the results from standard $k-\varepsilon$ model owing to an extra time scale of the production rate and parameter describing effects of streamline curvature included in the dissipation rate equation.

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