• 한국데이터정보과학회:학술대회논문집
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• 한국데이터정보과학회 2005년도 추계학술대회
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• pp.189-202
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• 2005

Recently, the decrease of the number of a high-school graduate influences the number of limit matriculation. Based on the resident registration population, we forecast for the number of a high-school graduate until 2022 year in Daegu city. Most college and universities in Daegu city have to reduce the 37.5% of the number of limit matriculation until 2022 year to avert a disaster by prompt action.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1999년도 전력전자학술대회 논문집
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• pp.354-357
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• 1999

This paper is proposed Single phase Multi-Level AC-DC Converter. This is consist of diode bridge and switches. The number of the supply current levels depends on the number of the individual converter's current level. In this converter circuit the number of the levels is equal to 2(M+1) -1, where M is the number of Switching-Leg's number. In this paper is introduced converter with 31 current Level. If the number of current level is increased, smoother sinusoidal waveform can be obtained. The feasibility of the circuit is verified by computer simulation using PSIM

• International Journal of Air-Conditioning and Refrigeration
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• 제9권2호
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• pp.94-101
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• 2001

Fin effectiveness and efficiency of a thermally asymmetric rectangular fin are represented as a function of non-dimensional fin length, width, fip tip surface Biot number and the ratio of fin bottom surface Biot number to top surface Biot number. For this analysis, three dimensional separation of variables method is used. One of the results shows that fin effectiveness can be increased or decreased depending on the fin length as the fin tip surface Biot number increases while fin efficiency decreases without depending on that as the fin tip surface Biot number increases.

• East Asian mathematical journal
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• 제28권1호
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• pp.101-107
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• 2012

For each dimension exceeds 1, determining the number of multi-dimensional partitions of a positive integer is an open question in combinatorial number theory. For n ${\leq}$ 14 and d ${\geq}$ 1 we derive a formula for the function ${\wp}_d(n)$ where ${\wp}_d(n)$ denotes the number of partitions of n arranged on a d-dimensional space. We also give an another definition of the d-dimensional partitions using the union of finite number of divisor sets of integers.

• Kyungpook Mathematical Journal
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• 제61권1호
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• pp.205-212
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• 2021

We show that the forbidden detour move, essentially introduced by Kanenobu and Nelson, is an unknotting operation for virtual knots. Then we define the forbidden detour number of a virtual knot to be the minimal number of forbidden detour moves necessary to transform a diagram of the virtual knot into the trivial knot diagram. Some upper and lower bounds on the forbidden detour number are given in terms of the minimal number of real crossings or the coefficients of the affine index polynomial of the virtual knot.

• Journal of Mechanical Science and Technology
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• 제20권1호
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• pp.158-166
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• 2006

Extended Graetz problem in microtube is analyzed by using eigenfunction expansion to solve the energy equation. For the eigenvalue problem we applied the shooting method and Galerkin method. The hydrodynamically isothermal developed flow is assumed to enter the microtube with uniform temperature or uniform heat flux boundary condition. The effects of velocity and temperature jump boundary condition on the microtube wall, axial conduction and viscous dissipation are included. From the temperature field obtained, the local Nusselt number distributions on the tube wall are obtained as the dimensionless parameters (Peclet number, Knudsen number, Brinkman number) vary. The fully developed Nusselt number for each boundary condition is obtained also in terms of these parameters.

• 전자공학회논문지CI
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• 제40권6호
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• pp.1-8
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• 2003

Global carry propagation이 없는 redundant signed number에 의한 CORDIC 회로를 제안하였다. 이 number format은 Booth recording과 유사한 새로운 receding scheme을 가지고 가감산에서 carry 전파의 문제를 효과적으로 해결하였다. 여기서는 상수 scale factor를 갖고 삼각함수 계산을 하는 pipeline구조를 채택하였다. 이 CORDIC 회로의 동작시간은 채택한 operand bit에 상관없이 일정하다.

• 한국대기환경학회지
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• 제21권5호
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• pp.547-555
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• 2005

In this study, an analytical expression for aerosol mass transfer at spherical collector in the low Knudsen number region was obtained. Happel's zero shear stress cell model was extended in the low Knudsen number region and the result was compared with numerical solution results. The zero vorticity model based on the Kuwabara's cell model was also extended in the low Knudsen number region and compared with Happel's results. The results showed that both analytic and numerical solution agree very well with each other in low Knudsen number region. Happel's zero shear stress model also agrees with Kuwabara's zero vorticity model without significant loss of accuracy. The obtained solution converges to the original solution of Lee et al. (1999) when Knudsen number approaches to zero. Subsequently, this study derived most general type of analytic solution for aerosol mass transfer of spherical collector including the finite Knudsen number region.

• 한국분무공학회지
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• 제4권2호
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• pp.47-52
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• 1999

The prediction of the critical Reynolds number in the stability curie of liquid jet was mainly analyzed by the empirical correlations and the experimental data through the literature. The factors affecting the critical Reynolds number include Ohnesorge number, nozzle length-diameter ratio, ambient pressure and nozzle inlet type. The nozzle inlet type was divided into two groups according to the dependence of the critical Reynolds number on the length-to-diameter ratio of nozzle. The empirical correlations for the critical Reynolds number as a function of above factors mentioned are newly proposed.

• 한국병원경영학회지
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• 제21권1호
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• pp.43-50
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• 2016

The public medical centers are required to make efficient and profitable operation. The efficiency is usually measured by DEA(data envelopment analysis), and profitability is measured by medical income rate. But DEA is measured by relative, not absolute value. So, profitability rate is used alternatively for DEA. This study want to analyze the interchangeability between DEA ranking and medical income rate ranking among public medical centers. The return on total assets is same ranking with DEA on bed number, employee number and total asset, but 60-70% relationship with DEA on bed number and employee number, as input resources. The operating margin is similar ranking with DEA on bed number and employee number, but 50-60% relationship with DEA on bed number, employee number and total asset, as input resources.