• Nuclear Engineering and Technology
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• 제28권6호
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• pp.522-531
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• 1996

The adoption of expert systems mainly as operator supporting systems is becoming increasingly popular as the control algorithms of system become more and more sophisticated and complicated. The verification phase of knowledge base is an important part for developing reliable expert systems, especially in nuclear industry. Although several strategies or tools have been developed to perform potential error checking, they often neglect the reliability of verification methods. Because a Petri net provides a uniform mathematical formalization of knowledge base, it has been employed for knowledge base verification. In this work, we devise and suggest an automated tool, called COKEP(Checker Of Knowledge base using Extended Petri net), for detecting incorrectness, inconsistency, and incompletensess in a knowledge base. The scope of the verification problem is expanded to chained errors, unlike previous studies that assume error incidence to be limited to rule pairs only. In addition, we consider certainty factor in checking, because most of knowledge bases have certainty factors.

• 한국전산유체공학회지
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• 제8권3호
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• pp.21-31
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• 2003

A non-dissipative and very accurate one-dimensional upwind leapfrog method is extended to higher-order and multi-dimensional advection and acoustic equations. The higher-order versions are developed by extending the stencils in space and time. The schemes are then successfully applied to the classical test cases for advection and acoustics.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 1995년도 추계 학술대회논문집
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• pp.126-131
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• 1995

In this paper we study steady capillary-gravity waves in a two-layer fluid bounded above by a free surface and below by a horizontal rigid boundary with a small obstruction, Two critical speeds for the waves are obtained. Near the smaller critical speed, the derivation of the usual forced KdV equation (FKdV) fails when the coefficient of the nonlinear term in the FKdV vanishes. To overcome this difficulty, a new equation called a forced extended KdV equation (FEKdV) governing interfacial wave forms is obtained by a refined asymptotic method. Various solutions and numerical results of this equation are presented.

• 대한설비공학회지:설비저널
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• 제17권6호
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• pp.675-685
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• 1988

The purpose of this paper is to present the fundamental information for setting up more accurate and easier heat loads analysis method by examing and comparing Modified Bin Method with Dynamic loads calculation and Extended Degree Day Method. For this comparison, monthly and annual loads calculation are performed in perimeter zones of model office building in Seoul by the above each Method. The results of Modified Bin Method are approximated to those of Dynamic loads calculation Method, and the correlations of the methods are specifically described in this paper.

• Journal of Ship and Ocean Technology
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• 제4권2호
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• pp.13-23
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• 2000

A low-order potential based boundary element method is applied to the prediction of the flow around the cavitating propeller in steady or in unsteady inflow. For given cavitation number, the cavity shape is determined in an iterative manner until the kinematic and the dynamic boundary conditions are both satisfied on the approximate cavity boundary. In order to improve the solution behavior near the tip region, a hyperboloidal panel geometry and a modified split panel method are applied. The method is then extended to include the analysis of time-varying cavitating flows around the propeller blades via a time-step algorithm in time domain. In the method, the steady state oscillatory solution is obtained by incremental stepping in the itme domain. Finally, the present method is validated through comparison with other numerical results and experimental data.

• 방송공학회논문지
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• 제17권5호
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• pp.781-788
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• 2012

HEVC에서는 움직임 예측 시, 복잡도를 줄이기 위해 고속 탐색 기법이 사용된다. 고속 탐색 기법에는 SAD 계산 복잡도를 줄인 부-화소 단위 SAD 계산 기법(sub-sampled SAD)과 양-예측시의 단-예측 반복횟수를 줄인 간소화된 양-예측 기법으로 이루어져 있다. 고속 탐색 기법으로 인해 복잡도는 크게 줄었지만 부호화 이득 역시 감소하였다. 본 논문에서는 감소된 부호화 효율을 보상하기 위해 간소화된 양-예측을 확장하였고 확장된 양-예측으로 증가된 복잡도를 줄이기 위해 예측 비용 기반의 복잡도 감소 기법들을 제안한다. 예측 비용 기반의 복잡도 감소 기법은 양-예측 조기 종료 기법과 양-예측 생략 기법으로 이루어져 있다. HM 6.0 참조 소프트웨어와 비교하여 확장된 양-예측 기법과 예측 비용 기반의 복잡도 감소 기법으로 복잡도의 증가 없이 평균 0.42%의 BD-bitrate을 감소시켰다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.740-745
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• 2003

The so-called boundary node method (or NDIF method) that was developed by the authors has been extended for free vibration analysis of arbitrarily shaped plates with free edges. Since the proposed method is based on the collocation method, no integration procedure is needed on boundary edges of the plates and only a small amount of numerical calculation is required. A special coordinate transformation has been devised to consider the complicated free boundary conditions at boundary nodes. By the use of the special coordinate transformation, the radius of curvature involved in the free boundary conditions can be successfully dealt with. Finally, verification examples show that natural frequencies obtained by the present method agree well with those given by exact method and other analytical methods.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1998년도 가을 학술발표회 논문집
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• pp.109-116
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• 1998

The method of vibration analysis used is the one developed by the senior author. He developed and reported, in 1974, a simple but exact method of calculating the natural frequency of beam and tower structures with irregular cross-sections and attached mass/masses. Since 1989, this method has been extended to two-dimensional problems with several types of given conditions and has been reported at several international conferences. This method uses the deflection influence surfaces. The finite difference method is used for this purpose, in this paper. In order to reduce the pivotal points required, the three simultaneous partial differential equations of equilibrium with three dependent variables, w, M$_{x}$, and $M_{y}$, are used instead of the one forth order partial differential equation. By neglecting the M$_{x}$ terms, the size of the matrices needed to solve the resulting linear equations are reduced to two thirds of the "non-modified" equations.tions.

• KSBB Journal
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• 제17권1호
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• pp.33-37
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• 2002

PLGA 미립구로부터 G-CSF의 방출 거동 양상을 향상 시키기 위하여 G-CSF를 분자량 5000인 methoxy polyethylene glycol-aldehyde로 PEGylation 시켰다. 대부분의 G-CSF는 mono-PEGylation 되었으며, 이를 SDS-PAGE, HPLC, 및 펩타이드 지도 분석을 통해 확인하였다. W/O/W 방법을 사용하여 G-CSF 및 PEGylated G-CSF의 PLGA 미립구를 제조하였으며, 이때 봉입율은 높은 상태였다. 미립구내로 더 많은 G-CSF를 봉입하기 위하여 액상의 G-CSF 및 PEGylated G-CSF을 농축하였고 native gel과 gel filtration 크로마토 그래피를 통하여 단백질이 안정함을 확인하였다. 이렇게 제조한 PLGA 봉입체의 in vitro 방출 거동을 조사한 결과 PEGylated G-CSF는 native G-CSF에 비하여 더 오랜 시간 동안 방출이 지속되었고 최대 방출량도 증가하였다.

• Structural Engineering and Mechanics
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• 제2권3호
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• pp.285-294
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• 1994

Based on a fast and accurate method for the stationary random seismic response analysis for discretized structures(Lin 1992, Lin et al. 1992), a Ritz method for dealing with such responses of continuous systems in developed. This method is studied quantitatively, using cantilever shear beams for simplicity and clarity. The process can be naturally extended to deal with various boundary conditions as well as non-uniform Bernoulli-Euler beams, or even Timoshenko beams. Algorithms for both proportionally and non-proportionally damped responses are described. For all of such damping cases, it is not necessary to solve for the natural vibrations of the beams. The solution procedure is very simple, and equally efficient for a white or a non-white ground excitation spectrum. Two examples are given where various power spectral density functions, variances, covariances and second spectral moments of displacement, internal force response, and their derivatives are calculated and analyses. Some Ritz solutions are compared with "exact" CQC solutions.