• Journal of the Society of Naval Architects of Korea
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• v.29 no.3
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• pp.59-70
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• 1992

A Finite volume method for the computation of the two-dimensional, incompressible, steady, laminar Navier-Stokes equation is developed using a non-staggered grid system in a general curvilinear coordinate. The numerical pressure fluctuations, usually encountered when the non-staggered grid system is used, is suppressed by the momentum interpolation method. Flows around a NACA0012 foil section have been computed by the present method and the results show good agreements with other experimental and numerical ones.

• Journal of Intelligence and Information Systems
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• v.13 no.3
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• pp.141-160
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• 2007

User interface has been regarded as a crucial issue to increase the acceptance of mobile services. In special, even though to what extent the machine as speaker communicates with human as listener in a timely and polite manner is important, fundamental studies to come up with these issues have been very rare. Hence, the purpose of this paper is to propose a methodology of estimating politeness level in a certain context-aware setting and then to design a context-aware system for polite mobile interface. We will focus on Korean language for the polite level estimation simply because the polite interface would highly depend on cultural and linguistic characteristics. Nested Minkowski aggregation model, which amends Minkowski aggregation model, is adopted as a privacy-preserving similarity evaluation for case retrieval under distributed computing environment such as ubiquitous computing environment. To show the feasibility of the methodology proposed in this paper, simulation-based experiment with drama cases has performed to show the performance of the methodology proposed in this paper.

• Journal of the Society of Naval Architects of Korea
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• v.34 no.2
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• pp.27-38
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• 1997

This paper is concerned with the calculation of the wave resistance for SWATH ships based on a low order Rankine source panel method. Two types of free surface boundary conditions, Dawson type (double model approximation) and Kelvin type (free stream approximation) are used. For the free surface boundary calculation, an analytic differentiation is employed instead of implementing a finite difference scheme. Then, the radiation condition is satisfied by, so called, the panel shift method. The numerical results using the above two methods are compared with those using the thin ship/modified slender body approximation and also with the experimental results. The SWATH models considered are a single strut SWATH and a twin strut SWATH together with the variations of two demihull separation distance. In order to prove the validity of the program developed, the numerical calculations for a Wigley mono hull and Wigley twin hulls are compared with the available experimental results.

• Korean Journal of Optics and Photonics
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• v.33 no.6
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• pp.275-286
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• 2022

As a first step in the optical design process, we derive a recursive numerical calculation method that can give a solution to the Gaussian equation that the paraxial rays satisfy. Given the refractive power, the angle of incidence to the first principal plane of the lens, the angle of exit to the second principal plane of the lens, and the distance between the principal planes, the radii of curvature of the front and back surfaces of a lens can be obtained by applying the recursive numerical calculation method proposed in this paper according to the thickness of the lens. If a module consists of two or more lenses, the thickness and radius of curvature of each lens can be similarly determined after selecting the distance between the principal planes of the lens under the condition of the design specification while increasing the number of lenses one by one.

• Journal of Teachers' Pension
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• v.1
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• pp.189-241
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• 2016

1991년 사학연금제도에 재정계산제도가 도입되었으나 법적 근거만이 존재할 뿐 이를 위한 구체적인 시행주체 및 절차, 재정계산의 역할과 범위 등 주요 내용에 대한 명확한 규정이 결여되어 있다. 이에 따라 시기별로 재정계산 추진방법이 다소 상이한 측면이 있었으며, 결과적으로 사학연금 재정계산 실시의 일관성(coherency)과 신뢰성(credibility) 확보에 어려움이 노정되었다. 이러한 상황에서, 본 연구에서는 사학연금 재정계산 시행현황과 그 문제점을 살펴보고 국내·외 공적연금의 재정계산제도 시행사례를 비교·분석함과 동시에 정책적 시사점을 모색하였다. 이에 기초하여 우리나라 사학연금 재정계산제도의 향후 정책과제 및 개선 기본방향을 ①재정평가 및 재정계획 체계, ②재정계산 실시내용, ③재정계산보고서, ④담당주체 및 보고절차, ⑤재정계산 법적 근거 등을 위주로 하여 정책제언(政策提言)하였다. 이 글이 사학연금의 발전적인 재정계산 정책수립에 이바지하고 나아가서는 우리나라 공적연금의 지속가능한 재정정책 수립에도 중요한 밑거름이 되기를 기대한다.

• Proceedings of the Korea Contents Association Conference
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• 2014.11a
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• pp.41-42
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• 2014

대형 안테나 해석에서 큰 화두는 안테나 수치 계산 속도를 높이는 것이다. 현재 인기를 얻고 있는 병렬 처리 방식인 OpenMP, MPI, CUDA를 이용하여 안테나 수치 계산을 병렬화할 경우 발생하는 단점을 제시하고, 각 병렬 처리법의 장점도 소개한다.

• Journal of Korea Foundry Society
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• v.22 no.6
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• pp.299-303
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• 2002

수정된 SIMPLE법과 VOF의 결합으로 predictor-two step corrector-VOF라고 불리는 새로운 알고리즘이 주조 시 용탕 충전과정을 해석하기 위해 개발되었다. 운동량보존으로부터 유도된 새 2단계 속도 경계조건 처리법은 용탕의 자유표면을 추적하는 데 사용되었다. 본 연구에서는 2개의 예제 계산을 통해 계산정확도와 속도에 대한 Courant 수의 영향을 살펴보았다. 그 결과 적당한 Courant 수의 증가는 계산 정확도의 감소 없이 용탕 계산 속도를 향상시킬 수 있는 것으로 나타났다. 또한 만족할 만한 계산 정확도와 효율이 이 알고리즘의 실제 제품 해석을 통해 얻어졌다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.6
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• pp.625-632
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• 2011

The ignition characteristics of a $CH_4$/hot air counterflow diffusion flame were investigated numerically using a flame-controlling continuation method. For the chemical reactions, the GRI-v1.2 reaction mechanism was used in the simulation. The maximum flame temperature was presented in the space of the inverse global strain rate, and showed S-curve-type behavior. The flame temperatures and velocities of the upper and middle branches were compared for different global strain rates. In addition, the global strain rate was compared with the local strain rates defined at the flame surface and the boundaries of the fuel and oxidizer sides of the fuel/air mixing layer. These local strain rates correlated well with the global strain rate.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.39 no.1
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• pp.27-32
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• 2003

Under the assumption of potential flow, free-surface flow around a hydrofoil is calculated by the high-order spectra1!boundary-integral method, This method is one of the most efficient numerical methods by which the nonlinear interactions between hydrofoil and free-surface can be simulated in time-domain. In this method. the wave potential which represents the nonlinear evolution of free-surface is solved by the high-order spectral method and the body potential which provides the effects of hydrofoil and shed vortex is solved by the boundary-integral method. The calculated free-surface profiles which are generated by a uniformly translating hydrofoil are compared with other experimental results. And they show relatively good agreements each other. As another example, free-surface flow generated by a heaving and translating hydrofoil is calculated and discussed.

• Applied Chemistry for Engineering
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• v.17 no.3
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• pp.317-320
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• 2006

The optimum mobile phase condition for analysis of the six purine derivatives (caffeine, guanine, hypoxanthine, purine, theobromine, and theophylline) were determined by a HCI program. Reversed-phase HPLC system was used with the binary mobile phase, water and methanol. Three retention models (Snyder, Langmuir, and Binary polynomial) were considered to predict the retention factors. The elution profiles were calculated by the plate theory based on the binary polynomial retention model. From the final calculated results, the binary polynomial retention model showed the best agreements between the calculated and experimental data. In the isocratic mode, the optimum mobile phase composition of water/methanol is 93/7(v/v). However, we used step-gradient mode to decrease the run-time ($1^{st}$ mobile phase : water/methanol = 93/7 (v/v), gradient time : 5 min, $2^{nd}$ mobile phase : water/methanol = 75/25 (v/v)). The experimental and simulated profiles of above the two conditions show a good agreement.