• 한국지리정보학회지
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• 제8권3호
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• pp.84-95
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• 2005

본 논문은 가시권역의 최대화를 만족하는 가시권 분석에 있어 지형요소가 어떻게 이용될 수 있으며 이러한 최적 다중 가시점 탐색 문제에 있어 지형요소의 이용이 얼마나 효과적인지를 살펴보는 연구이다. 이를 위하여 다양한 지형상태를 반영하는 지역의 DEM 자료와 각 DEM자료에 대한 지형요소 (peak, pass, pit)의 특정을 반영한 여섯 종류의 탐색방법을 제시하고 전통적인 공간 휴리스틱 (spatial heuristic)과의 비교 분석 (계산 시간과 총 가시권역 크기)을 통해서 지형요소를 이용한 방법의 효율성과 적용 가능성을 살펴보았다. 연구결과로써, 가시구역의 중복을 최소화하기 위해 제시된 버퍼링을 이용한 방법의 경우, 비록 공간 휴리스틱 방법에 비해 적은 가시구역 면적을 제시하였지만, 컴퓨팅 시간적인 측면에서 많은 이점을 제공하고 있음을 볼 수 있다. 또한 연구지역의 DEM상의 각각의 개별 그리드 셀을 대상으로 전체 DEM에 대해 계산된 가시구역을 이용한 방법의 경우, 비록 부가적인 계산 시간이 소요됨에도 불구하고 단순한 지형요소를 이용한 방법보다 향상된 분석 결과를 제시하였음을 알 수 있다.

• 약학회지
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• 제23권3_4호
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• pp.147-152
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• 1979

Experiments were carried out to investigate for the interaction between FAD solution and synthetic resin containers made of polyvinylchloride(PVC), polyethylene(PE), and polycarbonate(PC), and for the effect of glycyrrhizine or malic acid on stabilization of FAD in aqueous solution by accelerated stability analysis. Analysis of FAD was determined by means of spectrometer and by separating by paper chromatography and metal ions were detected by atomic absorption spectrophotometer, which were extracted from containers by means of Food and Additive Regulation Standard. The thermal decomposition of FAD in aqueous solution was pseudo first order reaction and it was inhibited by adding glycyrrhizine or malic into the solution. PVC, PE and PC containers accelerated the decomposition of FAD in solution. It is assumed that bivalent heavy metals in resin containers may catalize the hydrolysis of FAD. The metals detected from the containers were Ca, Zn, Cu, Fe, Pb and Cd. And the total amounts of detected metals from PVC were 6.2mcg/cm$^{2}$, PE, 5.5mcg/cm$^{2}$, and PC, 2.7mcg/cm$^{2}$ which were proportional to the rate constant of FAD decomposition in aqueous solution.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 춘계학술대회 논문집
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• pp.603-607
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• 1995

Static and dynamic response of a mechanical system can be easily and readily obtained using an approximate method such as the Finite Element Method. However, FE solution cannot be totally trusted, since there are many numerical uncertainies inherent in an FE analysis. FE solution error can be estimated based on FE analysis result. Error estimator shows the quality of the FE solution, and helps FE users to enhance the accuracy of the FE solution.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2000년도 춘계학술발표대회 논문집
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• pp.38-42
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• 2000

In this study, the low velocity impact behavior of the composite laminates has been described by using 3 dimensional nonlinear finite elements. To describe the geometric nonlinearity due to large deformation, the dynamic contact problem is formulated using the exterior penalty finite element method on the base of Total Lagrangian formulation. The incremental decomposition is introduced, and the converged solution is attained by Newton-Raphson Method. The Newmark's constant-acceleration time integration algorithm is used. To make verification of the finite element program developed in this study, the solution of the nonlinear static problem with occurrence of large deformation is compared with ABAQUS, and the solution of the static contact problem with indentation is compared with the Hertz solution. And, the solution of low velocity impact problem for isotropic material is verificated by comparison with that of LS-DYNA3D. Finally the contact force of impact response from the nonlinear analysis are compared with those from the linear analysis.

• 한국환경과학회지
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• 제29권10호
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• pp.951-959
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• 2020

This study aimed to re-establish the conservation area reflecting landscape ecological value through scenario program, targeting Odaesan National Park. The basic data were mapped in watershed planning units, which were set considering topographical and ecological values. The framework of Marxan with Zones, using an indexation process, was using the mapped indicators. Each best solution according to the scenarios was assessed through sensitivity analysis, and a final solution was selected among the best solutions, considering criteria including area ratio of conservation area and grouping. Lastly, the final solution was verified in the overlap analysis with recent zonation. As a result, through the framework of Marxan with Zones, the best solution of scenario 1, which was set by the highest conservation criteria was selected as the final solution, and the area ratio of conservation area and grouping was excellent. As for the overlap analysis, the suggested conservation area was improved compared to recent zonation in terms of the area ratio (39.4%), biotope grade I (35.6%) and the distribution points (7 places) of legally protected species.

• 한국구조물진단유지관리공학회 논문집
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• 제2권1호
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• pp.129-135
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• 1998

The characteristic of load-distribution is investigated by using nonlinear analysis with a field loading test of existing bridge In this study, nonlinear load-distribution technique for quantitative analysis was adopted. The results were compared with linear solution technique with data from failure test at existing RCT-girder bridge and examine the adequacy of the failure mode. The results of this study showed that the linear solution technique and the proposed nonlinear solution technique agreed well in linear region but did not matched well in nonlinear region because of load-redistribution, and that the effect of load-redistribution was considered to analysis of nonlinear region by linear solution.

• Advances in Computational Design
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• 제9권2호
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• pp.81-96
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• 2024

Modeling and analyzing the dynamic behavior of fluid-soil-structure interaction problems are crucial in structural engineering. The solution to such coupled engineering systems is often not achievable through analytical modeling alone, and a numerical solution is necessary. Generally, the Finite Element Method (FEM) is commonly used to address such problems. However, when dealing with coupled problems with complex geometry, the finite element method may not precisely represent the geometry, leading to errors that impact solution quality. Recently, Isogeometric Analysis (IGA) has emerged as a preferred method for modeling and analyzing complex systems. In this study, IGA based on Non-Uniform Rational B-Splines (NURBS) is employed to analyze the seismic behavior of concrete gravity dams, considering fluid-structure-foundation interaction. The performance of IGA is then compared with the classical finite element solution. The computational efficiency of IGA is demonstrated through case studies involving simulations of the reservoir-foundation-dam system under seismic loading.

• 대한한방부인과학회지
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• 제19권2호
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• pp.34-48
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• 2006

Purpose : This study was conducted to investigate the inhibitory effects of Dangguijakyaksan on cell proliferation in HeLa cells. Methods : Human uterine cervical carcinoma HeLa cells were cultured in the 1%, 5% and 10% concentration of Dangguijakyaksan extract solution for 24 hours, 48 hours and 72 hours for the direct inhibitory effects of Dangguijakyaksan. Afterwards, we executed the analysis of the effect of Dangguijakyaksan extract solution on cell proliferation inhibition using XTT assay, molecular biological method through MAP kinase activity and FACS analysis of caspase activity in the HeLa cells. Results : After 24, 48 and 72 hours cultivation, Dangguijakyaksan extract solution group showed significant decrease of HeLa cells except 1% solution after 24 hours compared with the control group. In the FACS analysis, Dangguijakyaksan extract solution groups showed increase of caspase activity except 1% solution after 48 hours compared with the control group. In the XTT assay, the caspase-3 activities were increased in Dangguijakyaksan extract solution groups except 1% solution after 24 hours in a dose-dependent manner. In the XTT study, cell activities were significantly decreased in 10% Dangguijakyaksan extract solution groups after 48 and 72 hours cultivation compared with the control group. In all Dangguijakyaksan extract solution groups, The activities of MAP kinase were decreased after 24, 48 and 72 hours cultivation compared with the control group. Conclusion : It could be concluded that Dangguijakyaksan is available to the inhibition of proliferation of human cervical carcinoma cell line in vitro.

• 한국표면공학회지
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• 제42권1호
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• pp.53-57
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• 2009

Recovery of heavy-metallic component from a waste solution of factory was undertaken by the solar cell electricity. The solution was obtained from an electrolytic etching process of 316L stainless steel. The electrolysis of the solution for recovery of heavy metallic components was made with platinum plated titanium mesh anode and copper plate cathode. Analysis for the solution and electro-winned materials were made by EDS, XRD and SEM. Iron, chromium, and sulfur components were recovered on the cathode from the solution. Result of EDS analysis for the electro-winned materials revealed that some metal oxide were contained in the recovered material. The recovered materials were expected to have metallic form only by the electrolysis, but metal compounds were contained because of weak solar cell power. Nickel and manganese component in the solution doesn't recovered by this electrolysis process, but they made a sludge with phosphoric acid in the solution.

• 한국소음진동공학회논문집
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• 제17권10호
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• pp.946-949
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• 2007

This paper discusses the lateral vibration of a beam with boundary condition of one end fixed and the other end free. The uniform beam has a solution by summation of some simple exponential functions. But if its shape is not uniform, its solution could be by Bessel's function or mathematical solution could not exist. Even if the solution of Bessel's function exists, as Bessel function is a series function, we must get the solution by numerical method. Author had proposed the solution of the matrix method by Ritz's method and a new mode shape function, and had earned the good results for a wedge beam. Hereby a vibration analysis for the tapered beam with circle cross section was executed, and so good results were showed.