• Proceedings of the KIEE Conference
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• 1993.07a
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• pp.489-491
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• 1993

Many optimization problem or multiple attribute, multiple alternative decision making problem may have fuzzy evaluation factors. In this case, fuzzy number operation technique is needed to evaluate and compare object functions which become fuzzy sets. Generally, fuzzy number operations can be defined by extension principle of fuzzy set theory, but it is tedious to do fuzzy number operations by using extension principle when the membership functions are defined by complex functions. Many fast methods which approximate the membership functions such as triangle, trapezoidal, or L-R type functions are proposed. In this paper, a fast fuzzy number operation method is proposed which do not simplify the membership functions of fuzzy numbers.

• IE interfaces
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• v.13 no.2
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• pp.273-280
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• 2000

Time-tradeoff measures and healthy years equivalents were assessed and compared through an empirical study based on Multi-attribute utility theory. The study included 33 student subjects as a pilot study, and 54 end-stage renal disease patients in Wisconsin. The two outcome measures were compared with the survival duration of 1, 5, and 10 years. The results of the study show that the time-tradeoff method and the two-stage method did not lead to the same numerical quantities, although they aim to measure the same quantities (equivalent numbers of healthy years) theoretically. The healthy years equivalents involved more inconsistencies, and were less reliable than the time-tradeoff measures. Overestimation of the healthy years equivalents was observed. This seemed to be caused by the complex procedure of the two-stage method as well as by the preferences assessment biases. Based on the study experiences, the time-tradeoff measure would be recommended for problems involving generic medical applications and health policies.

• Journal of Welding and Joining
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• v.20 no.1
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• pp.83-90
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• 2002

Metal Transfer in gas metal arc (GMA) welding is a complex phenomenon affected by many parameters of the welding conditions and material properties. In this research, the correlation equation between the welding condition and detaching droplet size and detaching velocity in GMA welding was studied via recession analysis on the results of numerical analysis using the volume-of-fluid (VOF) method. Welding parameters and material properties were grouped into three dimensionless numbers and detaching droplet size was expressed as the function of them. Second order and exponential multi-variable correlation forms were assumed, and the coefficients of these equations were calculated for globular and spray modes as well as entire transfer modes. Applying correlation equation into available experimental data, it shows good agreement.

• Journal of Marine Bioscience and Biotechnology
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• v.3 no.1
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• pp.48-53
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• 2008

Tanzania is a coastal state on the western Indian Ocean in Africa. In an artisanal or small scale fishery, the combination of large numbers of fishers and landing places, mixed gears and migrant fishers makes fisheries management an often complex task. Lack of capital, low level of technology, poverty and high cost of transport are major socio-economic problems in Tanzanian fisheries. The combined approach of community-based management and provision of education and training for extension workers and fishers themselves are required. It is also necessary to build the capacity of fisheries institutions to meet the human resources development challenge.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.3 s.246
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• pp.230-237
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• 2006

Flows in the cavity with pump out vane are calculated using the CFX-Tascflow CFD code. flow calculations are performed for different values of vane height, numbers, leakage flow rate, and rotational speed. The flow is very complex and three dimensional with strong vortex and leakage flow over the vane. The variations of pressure coefficient and K-factor with these parameters and resulting effects on the thrust and torque are studied. The present study contributes to showing the capability of flow simulation of back cavity with pump-out vane. The calculated results are good enough to be used back cavity design.

• Communications of the Korean Mathematical Society
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• v.16 no.4
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• pp.585-594
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• 2001

Let η be the complex upper half plane, let h($\tau$) be a cusp form, and let $\tau$ be an imaginary quadratic in η. If h($\tau$)$\in$$\Omega$( $g_{2}$($\tau$)$^{m}$ $g_{3}$ ($\tau$)$^{ι}$with $\Omega$the field of algebraic numbers and m. l positive integers, then we show that h($\tau$) is integral over the ring Q[h/$\tau$/n/)…h($\tau$+n-1/n)] (No Abstract.see full/text)

• Journal of the Korean Mathematical Society
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• v.43 no.3
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• pp.529-538
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• 2006

In this paper we derive the central limit theorem for ${\sum}^n_{i=l}\;a_{ni}{\xi}_{i},\;where\;\{a_{ni},\;1\;{\le}\;i\;{\le}n\}$ is a triangular array of non-negative numbers such that $sup_n{\sum}^n_{i=l}\;a^2_{ni}\;<\;{\infty},\;max_{1{\le}i{\le}n\;a_{ni}{\to}\;0\;as\;n{\to}{\infty}\;and\;{\xi}'_{i}s$ are a linearly positive quadrant dependent sequence. We also apply this result to consider a central limit theorem for a partial sum of a generalized linear process of the form $X_n\;=\;{\sum}^{\infty}_{j=-{\infty}}a_{k+j}{\xi}_{j}$.

• Bulletin of the Korean Mathematical Society
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• v.53 no.2
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• pp.387-398
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• 2016

Let X be a vector space over a field K of real or complex numbers and $k{\in}{\mathbb{N}}$. We prove the superstability of the following generalized Golab-Schinzel type equation $f(x_1+{\limits\sum_{i=2}^p}x_if(x_1)^kf(x_2)^k{\cdots}f(x_{i-1})^k)={\limits\prod_{i=1}^pf(x_i),x_1,x_2,{\cdots},x_p{\in}X$, where $f:X{\rightarrow}K$ is an unknown function which is hemicontinuous at the origin.

• Applied Chemistry for Engineering
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• v.30 no.4
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• pp.445-452
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• 2019

Shear thickening is an intriguing phenomenon in the fields of chemical engineering and rheology because it originates from complex situations with experimental and numerical measurements. This paper presents results from the numerical modeling of the particle-fluid dynamics of a two-dimensional mixture of colloidal particles immersed in a fluid. Our results reveal the characteristic particle behavior with an application of a shear force to the upper part of the fluid domain. By combining the lattice Boltzmann and discrete element methods with the calculation of the lubrication forces when particles approach or recede from each other, this study aims to reveal the behavior of the suspension, specifically shear thickening. The results show that the calculated suspension viscosity is in good agreement with the experimental results. Results describing the particle deviation, diffusivity, concentration, and contact numbers are also demonstrated.

• Bulletin of the Korean Mathematical Society
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• v.56 no.1
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• pp.45-56
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• 2019

The aim of this paper is to investigate the problems of meromorphic functions sharing values concerning periodicities and shifts. In this paper we prove the following result: Let f(z) and g(z) be two nonconstant entire functions, let $c{\in}{\mathbb{C}}{\setminus}\{0\}$, and let $a_1$, $a_2$ be two distinct finite complex numbers. Suppose that ${\mu}(f){\neq}1$, ${\rho}_2(f)<1$, and f(z) = f(z+c) for all $z{\in}{\mathbb{C}}$. If f(z) and g(z) share $a_1$ CM, $a_2$ IM, then $f(z){\equiv}g(z)$. Moreover, examples are given to show that all the conditions are necessary.