• 한국지리정보학회지
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• 제7권1호
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• pp.39-51
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• 2004

본 연구는 선형사상 일반화에서 사상들 간의 공간적 충돌, 벡터변위에 따른 위치변동 등의 문제를 개선하기 위해 새로운 Simoo 알고리즘을 제안하고자 하였다. Simoo 알고리즘의 원리는 단순화와 완만화를 채택하였다. Simoo 알고리즘에서 사용된 임계치는 수선길이, 편각, 평균 vertex 길이이다. Simoo 알고리즘은 축척별 적용 가능, 지도학적 세련미, 자료점의 위치 변동에 따른 논리적 오류 발생의 감소, 공간현상특징 유지 등의 특징을 갖는다. Simoo 알고리즘의 적용 결과는 Douglas-Peucker 알고리즘과 비교하였다. 그 결과 두 알고리즘에서 해안선과 하계망 길이는 97% 이상 유지되었으며, 자료점 제거율은 Simoo보다 Douglas-Pecuker 알고리즘이 효과적이었고, 사상들간의 충돌은 Simoo에서 최소화되었다. 선의 곡률과 완만화는 Simoo 적용시 축척에 따라 감소하였다. 결과적으로 Douglas-Peucker보다는 Simoo 알고리즘이 지도학적 일반화에 적합하다고 볼 수 있다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집D
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• pp.759-764
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• 2001

Heat (mass) transfer characteristics have been investigated on the endwall of a large-scale linear turbine cascade passage under a combustor-level high free-stream turbulence with a large length scale. Local heat (mass) transfer coefficients are measured by using the naphthalene sublimation technique. The result shows that local heat (mass) transfer on the endwall is greatly enhanced in the central region of the turbine passage, but there is no noticeable change in the local heat (mass) transfer in the region suffering severe heat load. Under the high free-stream turbulence, the local heat (mass) transfer coefficient shows more uniform distribution and its average value across the whole endwall region is increased by 26% of that at low turbulence condition. The heat (mass) transfer data on the endwall strongly supports that well-organized vortices near the endwall tends to suffer an suppression by the high free-stream turbulence.

• Journal of Computing Science and Engineering
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• 제2권2호
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• pp.200-219
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• 2008

The effective management of uncertainty is one of the most fundamental problems in medical decision making. According to the literatures review, most medical decision models rely on point estimates for input parameters. However, it is natural that they should be interested in the relationship between changes in those values and subsequent changes in model output. Therefore, the purpose of this study is to identify the ranges of numerical values for which each option will be most efficient with respect to the input parameters. The Nonhomogeneous Poisson Process(NHPP) was used for describing the behavior of aging chronic diseases. Three kind of failure models (linear, exponential, and power law) were considered, and each of these failure models was studied under the assumptions of unknown scale factor and known aging rate, known scale factor and unknown aging rate, and unknown scale factor and unknown aging rate, respectively. In addition, this study illustrated developed method with an analysis of data from a trial of immunotherapy in the treatment of chronic Granulomatous disease. Finally, the proposed design of Bayesian value of information analysis facilitates the effective use of the computing capability of computers and provides a systematic way to integrate the expert's opinions and the sampling information which will furnish decision makers with valuable support for quality medical decision making.

• 전자공학회논문지SC
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• 제39권5호
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• pp.8-17
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• 2002

본 논문에서는, 섭동과 제어기 이득 섭동을 갖는 이산 대규모 시간지연 시스템의 강인 비약성 제어기 설계에 관하여 논한다. 리아프보프 해석법을 의거하여 선형행렬 부등식으로 표현되는 주어진 시스템의 강인 안정화를 꾀하는 상태 궤환 제어기의 존재를 보장하는 조건 식을 구한다. 이 조건 식의 해로부터 각 부 시스템에서의 제어기의 이득 및 제어기의 비약성 지수도 얻을 수 있다. 제시된 선형행렬 부등식은 잘 알려진 최적화 기법으로 쉽게 풀 수 있으며, 예제를 통하여 제어기 설계 방법을 보인다.

• Smart Structures and Systems
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• 제13권4호
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• pp.501-515
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• 2014

This paper presents a linear computational homogenization framework to evaluate the effective (or generalized) electromechanical coupling coefficient (EMCC) of adaptive structures with piezoelectric structural fiber (PSF) composite elements. The PSF consists of a silicon carbide (SiC) or carbon core fiber as reinforcement to a fragile piezo-ceramic shell. For the micro-scale analysis, a micromechanics model based on the variational asymptotic method for unit cell homogenization (VAMUCH) is used to evaluate the overall electromechanical properties of the PSF composites. At the macro-scale, a finite element (FE) analysis with the commercial FE code ABAQUS is performed to evaluate the effective EMCC for structures with the PSF composite patches. The EMCC is postprocessed from free-vibrations analysis under short-circuit (SC) and open-circuit (OC) electrodes of the patches. This linear two-scale computational framework may be useful for the optimal design of active structure multi-functional composites which can be used for multi-functional applications such as structural health monitoring, power harvest, vibration sensing and control, damping, and shape control through anisotropic actuation.

• 대한한방부인과학회지
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• 제28권4호
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• pp.31-45
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• 2015

Objectives : The purpose of this study is to examine the relationship between the symptoms of primary dysmenorrhea and pulse energy of Chon, Gwan and Cheok. Methods The subjects of this study who had certain range of dysmenorrhea symptom. The degree of dysmenorrhea were assessed by Visual Analog Scale (VAS), Multidimensional Verbal Rating Scale (MVRS), Cox Menstrual Symptom Scale (CMSS) and measured by 3D Blood Pressure Pulse Analyzer(3D-MAC) tests at menstruation start date. Data analysis included descriptive statistics and multiple linear regression using the SPSS/WIN 18.0 program. Results : The induced results are as follows;The induced results are as follows 1. There were no significant relationship between the pulse energy and the sum values of VAS, MVRS and checking part of severity of CMSS. 2. The frequency domain of CMSS were significantly associated with pulse energy. 3. In linear regression models, the model of Left Chon had the especially highest value of explanatory power. (R ² = 0.517) Conclusions : The pulse energy changes are related to the symptoms of primary dysmenorrhea.

• Computers and Concrete
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• 제5권2호
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• pp.117-134
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• 2008

An experimental and numerical research was conducted to gain a deeper insight on the structural behaviour of deep-beams with indirect supports and to assess the size effects in the ultimate state behaviour. The experimental campaign focused on the influence of the reinforcement tie distribution height on the compression check of the support region and on the benefits of using unbonded prestressing steel. Three reduced scale specimens were tested and used to validate the results obtained with a nonlinear finite element model. As a good agreement could be found between the numerical and the experimental results, the numerical model was then further used to perform simulations in large scale deep-beams, with dimensions similar to the ones to be adopted in a practical case. Two sources of size effects were identified from the simulation results. Both sources are related to the concrete quasi-brittle behaviour and are responsible for increasing failure brittleness with increasing structural size. While in the laboratory models failure occurred both in the experimental tests as well as in the numerical simulations after reinforcement yielding, the numerically analysed large scale models exhibited shear failures with reinforcement still operating in the elastic range.

• 대한수학회지
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• 제51권2호
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• pp.267-288
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• 2014

We propose and analyze two-scale product approximation for semilinear heat equations in the mixed finite element method. In order to efficiently resolve nonlinear algebraic equations resulting from the mixed method for semilinear parabolic problems, we treat the nonlinear terms using some interpolation operator and exploit a two-scale grid algorithm. With this scheme, the nonlinear problem is reduced to a linear problem on a fine scale mesh without losing overall accuracy of the final system. We derive optimal order $L^{\infty}((0, T];L^2({\Omega}))$-error estimates for the relevant variables. Numerical results are presented to support the theory developed in this paper.

• Coupled systems mechanics
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• 제8권2호
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• pp.99-109
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• 2019

This work investigates the accuracy and performance of a $FE^2$ multi-scale implementation used to predict the behavior of composite materials. The equations are formulated assuming the small deformations solid mechanics approach in non-linear material models with hardening plasticity. The uniform strain boundary conditions are applied for the macro-to-micro transitions. A parallel algorithm was implemented in order to solve large engineering problems. The scheme proposed takes advantage of the domain decomposition method at the macro-scale and the coupling between each subdomain with a micro-scale model. The precision of the method is validated with a composite material problem and scalability tests are performed for showing the efficiency.

• 대한수학회지
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• 제33권1호
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• pp.69-79
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• 1996