• 한국항행학회논문지
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• 제27권4호
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• pp.365-373
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• 2023

무인 항공기는 다양한 분야에서 널리 활용되고 있으며, 실시간 경로 재계획은 이들 기기의 안전성과 효율성을 향상하는 핵심 요소이다. 본 논문에서는 RRT*와 LOSPO를 기반으로 한 실시간 경로 재계획 기법을 제안한다. 제안된 기법은 먼저 RRT* 알고리즘을 활용하여 초기 경로를 생성하고, LOSPO를 이용하여 경로를 최적화한다. 또한 최적화된 경로를 궤적으로 변경하여 실제 시간과 항공기의 동적한계를 고려할 수 있다. 이 과정에서 환경 변화와 충돌 위험을 실시간으로 감지하고, 필요한 경우 경로를 재계획함으로써 안전한 운행을 유지한다. 이 방법은 시뮬레이션을 통한 실험을 통해 검증되었다. 본 논문의 결과는 무인 항공기의 실시간 경로 재계획에 관한 연구에 중요한 기여할 것으로 기대한다. 또한 이 기법을 다양한 상황에 적용함으로써 무인 항공기의 안전성과 효율성을 향상시킬 수 있다.

• 한국통신학회논문지
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• 제21권1호
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• pp.91-102
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• 1996

ATM(asynchronous transfer mode)망에서 멀티미디어 트래픽이 효율적으로 전송되기 위해서는 전송되는 트래픽의 특성이 충분한 고려된 경로설정이 이루어져야 한다. 본 논문에서는 ATM망의 가상경로/가상채널의 특성을 기반으로한 점 대 다중점 경로설정 알고리즘을 제안한다. 제안한 알고리즘은 가상경로 트리를 사용하며 경로설정시 가상경로/가상채널 스위칭의 특성이 반영된 비용함수를 사용하였다. 또한 비용함수는 링크 비용, 지연 및 지연에 대한 가중치로 구성되며 지연에 대한 가중치는 트래픽의 지연감도에 의해 결정된다. 제안한 알고리즘은 트래픽의 지연한계를 만족시킬 수 있는 경로를 설정할 뿐만 아니라, 동일한 경로설정 비용을 가지는 지연한계내의 경로중 지연을 최적화하는 경로를 선택할 수있다. 또한 지연에 대한 가중치를 조절하여 지연 및 비용에 최적화된 알고리즘에 근사한 성능을 가질 수있다. 시뮬레이션 결과, 제안된 알고리즘은 가중치가 0.8에서 1사이에 존재할 때 경로설정 비용측면에서는 비용에 최적화된 알고리즘의 성능에 근사하였으며, 종단간 지연측면에 있어서는 지연이 강하게 반영된 알고리즘의 성능에 근사되었다.

• 한국항해항만학회지
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• 제46권3호
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• pp.259-268
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• 2022

일반적인 구매자와 공급자 간의 관계와 달리, 구매자보다 공급자의 교섭력이 높은 경우가 있다. 이러한 관계는 특히 조선 산업에서 자주 찾아볼 수 있다. 본 연구는 Kraljic의 연구에서 제시된 전략품목(strategic items) 개념을 중심으로 연구하고자 한다. 본 연구는 공급자의 교섭력이 우위인 시장에서 구매자의 전략품목 구매에 영향을 미치는 요인을 살펴보는 것에 그 목적이 있다. 분석을 실시한 결과 환경요인과 신뢰요인 간의 경로계수가 가장 높은 것으로 나타났다. 또한 환경요인과 만족요인간의 경로계수도 차순위로 높은 것으로 나타났다. 또한 구매자가 지각하는 교섭력의 우열에 따른 인식차이가 존재하는지를 분석한 결과 일부 경로계수에서 유의한 결과를 발견하였다.

• 통상정보연구
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• 제9권1호
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• pp.23-41
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• 2007

This paper research the country image, the brand image, consumers' performances and the brand royalty with the path analysis on foreign automobile brands. Our empirical study testify the reliability analysis, the factor analysis and the path analysis with above variables by SPSS 12.0 and AMOS 4.0. The result of this research is that hypotheses H1, H3, H5 were significantly supported, whereas, hypotheses H2, H4 were rejected in the samples of American automobile. and in the samples of Japanese automobile, it was clearly revealed that hypotheses H2, H3, H4 were significantly supported, whereas, hypotheses H1, H5 were rejected. So, in Korean market, we should focus on the brand image strategy more than the country image to make the brand royalty with American automobile products. whereas, Japanese automobile products, another strategy is recommended.

• 한국자동차공학회논문집
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• 제4권3호
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• pp.112-121
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• 1996

Applications of bonded dissimilar materials such as metal/ceramics and resin/metal joints, are very increasing in various industry fields. It is required to find crack propagation direction and path applying to the fracture mechanics on the bonded joint of dissimilar meterials. In this paper, crack propagation direction and path were simulated numerically by using boundary element method. Crack propagation angle is able to easily determine based on the maximum stress concept. Fracture tests of Al/Epoxy dissimilar materials with an interface crack are carried out under various mixed mode conditions by using the specimens of bonded scarf joints. It is found that the experimental results are well coincide with the analysis results of boundary element method.

• 한국정밀공학회지
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• 제18권10호
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• pp.109-115
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• 2001

The compliance approach to the problem of load sharing between a cracked plate and multiple plate used to bridge the crack. The theory is validated by using calculated stress intensity factors for the multiple load path plate to reduce experimentally observed growth rate to a common base. Calculations are them made on the effect of multiple load path plate width on fatigue crack retardation in order to demonstrate the predictive capability of the technique.

• 한국멀티미디어학회논문지
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• 제21권11호
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• pp.1327-1332
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• 2018

An AGV(Automated Guided Vehicle) where is running on production automated system is related efficiency of production system similarly. On previous study proposed a path collision avoidance algorithms using shortest path of AGV. Running time about loading and unloading with shortest path of AGV is important factor to decide the production system efficiency. In this paper, we propose a method of shortest path and shortest time. Also propose the decision making method of collision avoidance position for setup a shortest runway for next command. To do verify the proposed method consist a simulation for AGV. Finally, we compare and analyse the proposed system between the existing system and show that our system can effectively the performance.

• 한국정밀공학회지
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• 제14권1호
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• pp.158-167
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• 1997

For the use of a mobile robot in dynamic environment, a collision-avoidance algorithm with moving obsta- cle is necessary. In this paper, a collsion-avoidance algorithm of a mobile robot is presented, when a mobile robot detects the collision with moving obstacle on the navigational path. Using reported positions of moving obstacle with sensors, the mobile robot predicts the next position of moving obstacle with possibility of collision. The velocity of moving obstacle is modeled as random walk process with Gaussian distribution. The optimal collision-avoidance path in which turning motion of the mobile robot is considered is generated with relative velocity between the mobile robot and moving obstacle. For the safety of collision-avoidance path, attractive potential with the safety factor is suggested. The simulation results using this algorithm show the mobile robot avoids collision with moving obstacle in many cases.

• Journal of information and communication convergence engineering
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• 제8권1호
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• pp.59-63
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• 2010

The shortest path between two points inside a simple polygon P is a minimum-length path among all paths connecting them which don't pass by the exterior of P. A linear time algorithm for computing the shortest path in a general simple polygon requires triangulating a given polygon as preprocessing. The linear time triangulating is known to very complex to understand and implement it. It is also inefficient in case that the input without very large size is given because its time complexity has a big constant factor. Two points of a polygon P are said to be L-visible from each other if they can be joined by a simple chain of at most two rectilinear line segments contained in P completely. An L-visible polygon P is a polygon such that there is a point from which every point of P is L-visible. We present the customized optimal shortest path algorithm for an L-visible polygon. Our algorithm doesn't require triangulating as preprocessing and consists of simple procedures such as construction of convex hulls and operations for convex polygons, so it is easy to implement and runs very fast in linear time.

• 한국정밀공학회지
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• 제29권6호
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• pp.640-647
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• 2012

Current electronic products are dominated by the laser processing and the application will be extended this time. Especially, demands for high precision laser processing with a large area has been increasing for a number of applications such as in solar cell battery, display parts, electronic component and automobile industry. In this paper we designed an on-the-fly system for ultrafast/high precision/large area laser processing. In addition, we have developed the path algorithm for large area. Expansion of the area in which laser processing is an important factor to handle the ultrafast/wide area processing, it will require a processing path. Processing path is path of 2- axis stage and stage of change in velocity can be smooth as possible. We proposed a path of the user concept using NURBS(Non-Uniform Rational B-Spline)method. Through our experiment with the chopper, was to prove the continuity of edge parts. Through basic shape experiments, we proved that large area can be processed using laser. We developed a simulation tool using Visual C++.