• 충청수학회지
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• 제23권4호
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• pp.773-784
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• 2010

The existence of solutions in Besov spaces for nonlinear heat equations having transcendental nonlinearity: $$\frac{\partial}{{\partial}t}u-{\Delta}u=F(u)$$ is investigated. In particular, it is proved the local existence and blow-up phenomena of the solutions in Besov spaces for nonlinear heat equations corresponding to two transcendental nonlinear functions $F(u){\equiv}{\mid}u{\mid}e^{u^2}$ and $F(u){\equiv}e^u$ of rapid growth.

• 한국언론정보학보
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• 제52권
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• pp.27-47
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• 2010

본 연구에서는 시장 환경적 특성과 함께 조직 내부의 재원 구성 및 조직 구성의 특성을 분석하고, 이 과정에서 조직과 환경, 조직과 조직, 조직 내부의 상호작용 특성과 문제점 등을 종합적으로 조망하고자 하였다. 이를 위해 지역 방송에서의 시장 환경적 특성과 조직 내부 구조, 그리고 재원 구조의 특성은 최근 3년간 발간된 각종 통계 자료를 평균하여 현실에서의 환경 요인을 분석하고자 하였으며, 이러한 외적인 환경과 내부 구조적 특징과 더불어 외부 환경과 타 조직, 그리고 조직 내부 상호작용 특성 및 각종 문제점 등을 내부 구성원들에 대한 심층 인터뷰를 통해 지역 방송사 조직과 외부환경과의 상호작용 특성과 그 문제점 등을 탐사적으로 분석하였다. 분석 결과, 제한된 지역 시장 환경에 경쟁 체제가 도입되고, 재원 확보 및 조직 구조가 열악한 속에서 지역 방송사 조직은 시장 환경의 확장과 조직 간, 조직 내 상호작용방식 전환을 통해 조직의 내적 역량의 열악함을 극복하고자 하지만, 상호작용 과정에서 발생하는 다양한 불확실성과 이해관계의 첨예한 대립 등으로 인해 적지 않은 어려움을 겪고 있는 것으로 분석되었다. 시장 환경의 불확실성과 한계를 극복하기 위한 제도적 방안이 제 효과를 발휘하지 못함에 따라, 역량 강화를 위한 투자와 장기적인 인사 정책 수립이 어렵게 되고, 이는 시점에 따른 인력 구조의 편중과 더불어 방송사 조직 내부의 불안정을 가져오는 주요한 구조적요인으로 작용하고 있는 것으로 해석 가능하다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권8호
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• pp.3435-3454
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• 2016

Device-to-device (D2D) communication is a potential solution to the incessant increase in data traffic on cellular networks. The greatest problem is how to control the interference between D2D users and cellular mobile users, and between D2D users themselves. This paper proposes a solution for this issue by putting the full control privilege in cellular network using the software-defined networking (SDN) concept. A software virtual switch called Open vSwitch and several components are integrated into mobile devices for data forwarding and radio resource mapping, whereas the control functions are executed in the cellular network via a SDN controller. This allows the network to assign radio resources for D2D communication directly, thus reducing interference. This solution also brings out many benefits, including resource efficiency, energy saving, topology flexibility, etc. The advantages and disadvantages of this architecture are analyzed by both a mathematical method and a simple implementation. The result shows that implementation of this solution in the next generation of cellular networks is feasible.

• Journal of Advanced Marine Engineering and Technology
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• 제29권5호
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• pp.509-518
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• 2005

Liquid film thickness in laminar film condensation for flow over a flat plate generally is so thin that both fluid acceleration and thermal convection within the liquid film can be neglected. An integral solution method is proposed to solve the conjugate problems of laminar film condensation and heat conduction in a solid wall. It is found that approximate solutions of the governing equations involve four physical parameters to describe the conjugate heat transfer problem for laminar film condensation. It is shown that the effects of interfacial shear. mass transfer and local heat transfer are strongly dependent on the thermo-physical properties of the working fluids and the Jacob number.

• 전기학회논문지
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• 제56권3호
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• pp.451-456
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• 2007

This paper presents a problem that reconfigure distribution power system using branch exchange method. Optimal reconfiguration problem calculates line loss, voltage condition about system states of all situations that become different according to line On/off status, and search for optimum composition of these. However, result is difficult to be calculated fast. Because radiated operation condition of system is satisfied using many connection and sectionalize switches in the distribution power system. Therefore, in this paper, optimization method for reducing system total loss and satisfying operating condition of radial and constraints condition of voltage is proposed using the fastest branch exchange. And optimal solution at branch exchange algorithm can be wrong estimated to local optimal solution according to initial operating state. Considering this particular, an initial operating point algorithm is added and this paper showed that optimal solution arrives at global optimal solution.

• 대한수학회보
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• 제46권3호
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• pp.409-434
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• 2009

In this paper, we consider a generalized Riemann problem of the first order hyperbolic conservation laws. For the case that excludes the centered wave, we prove that the generalized Riemann problem admits a unique piecewise smooth solution u = u(t, x), and this solution has a structure similar to the similarity solution u = $U{(\frac{x}{t})}$ of the correspondin Riemann problem in the neighborhood of the origin provided that the coefficients of the system and the initial conditions are sufficiently smooth.

• 대한기계학회논문집B
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• 제32권12호
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• pp.945-953
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• 2008

Laminar film condensation of saturated vapor in forced flow over a flat plate is analysed. The problem is formulated as exact boundary-layer solution and integral approximate solution. From numerical solutions of the governing equations, it is found that the energy transfer by convection and the effect of inertia term in the momentum equation in negligibly small for low pressure but quite important for high pressure. The condensate rate, liquid-vapor interfacial shear stress and local heat transfer are strongly dependent on the reduced pressure $P_r$ and the modified Jacob number Ja/Pr.

• Nuclear Engineering and Technology
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• 제49권6호
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• pp.1326-1338
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• 2017

The continuous energy Monte Carlo neutron transport code, MC21, was coupled to the CTF subchannel thermal-hydraulics code using a combination of Consortium for Advanced Simulation of Light Water Reactors (CASL) tools and in-house Python scripts. An MC21/CTF solution for VERA Core Physics Benchmark Progression Problem 6 demonstrated good agreement with MC21/COBRA-IE and VERA solutions. The MC21/CTF solution for VERA Core Physics Benchmark Progression Problem 7, Watts Bar Unit 1 at beginning of cycle hot full power equilibrium xenon conditions, is the first published coupled Monte Carlo neutronics/subchannel T-H solution for this problem. MC21/CTF predicted a critical boron concentration of 854.5 ppm, yielding a critical eigenvalue of $0.99994{\pm}6.8E-6$ (95% confidence interval). Excellent agreement with a VERA solution of Problem 7 was also demonstrated for integral and local power and temperature parameters.

• 한국전산구조공학회논문집
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• 제35권5호
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• pp.249-257
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• 2022

본 논문은 직접해법 기반 FETI 알고리즘의 개선 방안을 제시하였다. 개선 대상은 FETI-local로, 해당 알고리즘은 국부 Lagrange 승수를 통해 부영역 간 경계 문제를 정의한다. 부영역 경계 강성 및 하중 계산 단계의 경우, 전체 역행렬 계산 등 과도한 비용을 요구했던 기존 알고리즘을 Boolean 행렬 특성을 활용한 선택적 역행렬 성분 계산으로 개선하였다. 전역 경계 행렬식 계산 단계의 경우, 기존 단일 프로세서 연산을 다중 프론탈 기법 기반 병렬 연산으로 대체하였다. 제시된 FETI-local 알고리즘의 성능 개선은 64만 자유도 수치 예제를 통해 검증되었으며, 기존 대비 최대 97.8%의 계산 시간 감소가 달성되었다. 또한, 기존 대비 안정적이고 개선된 확장성이 가속 지표를 통해 확인되었다. 추가로, 432만 자유도의 대용량 계산 성능 비교가 제시된 알고리즘과 상용 프로그램인 ANSYS 간에 수행되었다. 그 결과, 계산 시간 측면에선 ANSYS가 우수하였으나, 프로세서 수에 따른 가속 성능 증가율 측면에선 제시된 알고리즘이 우수한 것이 확인되었다.

• Toxicological Research
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• 제18권1호
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• pp.79-85
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• 2002

YHB216 is one of new recombinant human erythropoietins (rHu-EPO) developed by Yuhan Research Institute. The rHu-EPO products are widely being used for the treatment of various types of anemia. As a series of safety studies on YHB216, we performed the local irritation test (dermal & ocular application) in male New Zealand White rabbits and micronucleus test in male ICR mice. In the skin irritation test, 0.5 ml of YHB216 10,000 IU/ml solution was applied to the back skin of rabbits for 24 hours and sub-sequent observation was performed. There was no induced response after the treatment and the primary irritation index (P.I.I.) was‘0’. In the eye irritation test, 0.1 ml of YHB216 10,000 IU/mL solution was instilled into the conjunctiva of the eye. No treatment-related reaction was observed at the cornea, iris, and conjunctiva. In the micronucleus test, YHB216 was administered intravenously to male mice (6 mice per group) at dose levels of 0, 6,250, 12,500, and 25,000 IU/kg. Bone marrow cells were collected at 24 hours after the treatment. YHB216 treated groups showed no significant difference in the P/N (polychromatic erythrocyte/ normochromatic erythrocyte) ratio and in the number of micronucleated polychromatic erythrocyte com-pared with the control. In conclusion, YHB216 was found to be a non-irritating material up to 10,000 IU/ml in the local irritation test and to be a non-mutagen up to 25,000 IU/kg in the micronucleus test.