• 한국안전학회지
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• 제11권2호
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• pp.16-24
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• 1996

In this study we simulate the fatigue test of a compact tension specimen and obtain the displacements, stresses and strains by using the finite element method. And we examine the path independency of $\Delta$J integral values and compare it with $\Delta$J integral values calculated from load-load line displacement curve. From the results of this study, we can find that $\Delta$J integral show the path Independency for saturated materials. We can also find that the path independency of $\Delta$J Is not satisfied when different material Is assumed near the crack tip, but the difference in $\Delta$J is small. And $\Delta$J integral values calculated from load-load line displacement is very analogous with those from integration path but always have lower values than those from integration paths. In the case of crack closing, we found that $\Delta$J integral values from load-load line displacement should be calculated with the load Increment values based on the crack opening point. The unsaturated material is also simulated and its $\Delta$J shows different values according to the path, but the difference is small.

• 대한교통학회지
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• 제33권2호
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• pp.192-203
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• 2015

보행자는 일반적인 보행로뿐만 아니라 건물을 통과하거나 넓은 공간을 가로지르는 등의 비정형적인 보행 경로를 통해 다양한 방식으로 이동한다. 본 연구는 이러한 보행 경로를 social path로 정의하여 보행 네트워크의 범주 안에 포함시켜 정의하였다. 기존의 보행 접근성 연구에서는 이러한 보행 경로를 고려하지 못해 대상지의 공간적 위계 수준과 각 가로의 연결성을 올바르게 평가하지 못하였다. 이를 개선하기 위해 본 연구는 대중교통의 요지임과 동시에 상업 시설이 밀집된 서울의 주요 대상지를 선정하여 social path의 효과 분석을 수행하였다. 이를 위해서는 네트워크 공간 분석에서 활용되는 space syntax 기법의 공간 통합도(Integration)를 평가 지표로 설정하였다. 분석 결과, social path로 인해 각 가로의 연결성이 변화됨과 동시에 보행자의 최적 경로가 합리적으로 바뀌는 것으로 나타났다. 특히, 대상지 내부의 주요 가로와 social path의 개선효과가 두드러졌다. 이러한 점을 통해 social path의 연결성이 뛰어나고 보행자의 최적 경로를 보다 현실적으로 구현할 수 있다는 점을 증명하였다.

• 대한전자공학회논문지TC
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• 제39권7호
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• pp.38-45
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• 2002

본 논문은 손실 매질 내에 매설된 선 전류 안테나에 의한 크기가 큰 완전도체 표적의 산란파를 해석하기 위한 전장적분식을 도출하였다. Sommerfeld 형태의 적분은 어떤 해석영역에 대하여 계산의 어려움과 제약들을 가지고 있으며, 많은 계산시간이 필요하다. 반면 최대 경사적분은 빠른 결과의 산출을 제공하였으며, 또한 그 계산 결과는 모든 해석 영역에 적용 가능하다. 임의의 완전도체 표적의 산란파는 최대경사적분법과 MOM 방법이 사용되었으며, 계산 결과는 가우시안 구적법과 GPOF 방법에 의해 비교되었다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권7호
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• pp.3393-3412
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• 2017

As a main challenge in network virtualization, virtual network embedding problem is increasingly important and heuristic algorithms are of great interest. Aiming at the problems of poor correlation in node embedding and link embedding, long distance between adjacent virtual nodes and imbalance resource consumption of network components during embedding, we herein propose a two-stage virtual network embedding algorithm NA-PVNM. In node embedding stage, resource requirement and breadth first search algorithm are introduced to sort virtual nodes, and a node fitness function is developed to find the best substrate node. In link embedding stage, a path fitness function is developed to find the best path in which available bandwidth, CPU and path length are considered. Simulation results showed that the proposed algorithm could shorten link embedding distance, increase the acceptance ratio and revenue to cost ratio compared to previously reported algorithms. We also analyzed the impact of position constraint and substrate network attribute on algorithm performance, as well as the utilization of the substrate network resources during embedding via simulation. The results showed that, under the constraint of substrate resource distribution and virtual network requests, the critical factor of improving success ratio is to reduce resource consumption during embedding.

• 로봇학회논문지
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• 제4권2호
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• pp.112-120
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• 2009

In this paper, a localization error recoverymethod based on bias estimation is provided for outdoor localization of mobile robot using different-type sensors. In the previous data integration method with DGPS, it is difficult to localize mobile robot due to multi-path phenomena of DGPS. In this paper, fault data due to multi-path phenomena can be recovered by bias estimation. The proposed data integration method uses a Kalman filter based estimator taking into account a bias estimator and a free-bias estimator. A performance evaluation is shown through an outdoor experiment using mobile robot.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2003년도 종합학술발표회 논문집 Vol.13 No.1
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• pp.64-68
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• 2003

For the purpose of the efficient derivation of the closed-form Green's functions by which MoM matrix elements can be analytically evaluated, the optimum approximation path which is deformed from the Sommerfeld integration path on the complex $k_{\rho}$-plane is proposed based upon the steepest descent method and three level approximation procedure.

• Nuclear Engineering and Technology
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• 제56권5호
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• pp.1603-1618
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• 2024

Emergency operation plans are indispensable elements for effective process safety management especially when unanticipated events occur under extreme situations. In the paper, a synthesis framework is proposed for the integration success path planning and performance analysis. Within the synthesis framework, success path planning is implemented through flow-directed signal tracing, renaming and reconstruction from a complete collection of Minimal Path Sets (MPSs) that are obtained using graph traversal search on GO-FLOW model diagram. The performance of success paths is then evaluated and prioritized according to the task complexity and probability calculation of MPSs for optimum action plans identification. Finally, an Auxiliary Feed Water System of Pressurized Water Reactor (PWR-AFWS) is taken as an example system to demonstrate the flow-directed MPSs search method for success path planning and performance analysis. It is concluded that the synthesis framework is capable of providing procedural guidance for emergency response and safety management with optimal success path planning under extreme situations.

• 한국정밀공학회지
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• 제18권6호
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• pp.19-26
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• 2001

• 대한수학회지
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• 제38권2호
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• pp.349-363
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• 2001

The analytic in mass operator-valued Feynman integral is related to integration with respect to unbounded set functions formed from the semigroup obtained by analytic continuation of the heat semigroup and the spectral measure of multiplication by characteristics functions.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 춘계학술대회 논문집
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• pp.573-577
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• 1995

An integration method for the hypersingular kernels, in the boundary integralequations used for the solution of crack-like problems in elasticity, has been developed. To isolate the stronger singularities, the actual boundaries are replaced by the smoothly curved auxiliary boundaries which provide the detoured, non-singular integration paths. The auxiliary boundary can be interpreted as a contracted form of the actual boundaries except for the singular element where the collocating point is located. For an optimal integration path for every singular collocation point, the auxiliary boundary may have different shape depending on the position of the collocation point on the singular element.