• 태양에너지
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• 제12권1호
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• pp.103-108
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• 1992

• 태양에너지
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• 제11권3호
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• pp.89-95
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• 1991

• 한국해양공학회지
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• 제23권6호
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• pp.67-70
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• 2009

Nesting and cutting path optimization have a great effect on the improvement of productivity in many industries such as shipbuilding, automotive, clothing, and so on. However, few researches have been carried out for the optimization of a cutting path algorithm. This study proposed a new method for cutting optimization using gravity center of cutting pieces and a genetic algorithm. The proposed method was tested for a sample plate including many different shapes of cutting pieces and compared to 2 other conventional methods. The test results showed that the new method had the shortest cutting path and the best effectiveness among the 3 methods.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권2호
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• pp.678-690
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• 2014

The current networks do not disclose information about a management domain due to scalability, manageability and commercial reasons. Therefore, it is very hard to calculate an optimal path to the destination. Also, due to poor information sharing, if an error occurs in the intermediate path, it is very difficult to re-search the path and find the best path. Hence, to manage each domain more efficiently, an architecture with top-level path computation node which can obtain information of separate nodes are highly needed This study aims to investigate a federation of a united network around NRN(National Research Network) that could allow resource sharing between countries and also independent resource management for each country. Considering first the aspects that can be accessed from the perspective of a national research network, ICE(Information Control Element) and GFO(Global Federation Organizer)-based architecture is designed as a top-level path computation element to support traffic engineering and applied to the multi-domain network. Then, the federation for the independent management of resources and resource information sharing among national research networks have been examined.

• 한국컴퓨터정보학회논문지
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• 제14권1호
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• pp.9-15
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• 2009

개미 집단 시스템은 조합 최적화 문제를 해결하기 위한 메타 휴리스틱 탐색 방법이다. 기존 개미 집단시스템은 전역갱신과정에서 탐색된 전역 최적 경로에 대해서만 페로몬 갱신을 수행하는데, 전역 최적 경로가 탐색되지 않으면 페로몬 증발만 일어나며 주어진 종료 조건을 만족할 때까지 아무리 많은 반복 수행에도 페로몬 강화가 일어나지 않는다. 본 논문에서 제안된 개선된 개미 집단시스템은 전역 최적 경로의 길이가 주어진 반복 사이클 횟수 동안 더 이상 향상되지 못하면 국부최적에 빠졌다고 평가하고 상태전이 규칙에서 파라미터 감소를 통해 다음 노드를 선택하게 하였다. 이로 인해, 상태전이 규칙에서 파라미터 감소에 의한 다양화 전략으로 탐색하는 결과가 최적 경로 탐색뿐만 아니라, 평균 최적 경로 탐색과 평균 반복횟수의 성능이 우수함을 보여 주었으며, 실험을 통해 그 성능을 평가하였다.

• 한국통신학회논문지
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• 제31권5B호
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• pp.397-404
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• 2006

최근 광네트워크 기반 IP 서비스가 증가함에 따라 GMPLS 관리 프레임워크는 더욱 중요해지고 있다. 본 논문에서는 이러한 GMPLS 네트워크의 장애 요인들 중 다중 경로 장애 시 사용자의 트래픽 엔지니어링 복구 요구조건을 만족하고 최적의 서비스에 대한 대체 경로를 찾을 수 있는 동적 GMPLS 경로 관리 알고리즘을 제안한다. 구체적으로 GMPLS 네트워크에서 복구 조건을 만족하는 대체 경로의 가용성 조건들을 도출하고 있다. 또한 고속 대체 경로 설정 알고리즘을 제안하여 사용자의 복구 요구조건을 만족하고 서비스의 중지를 최소한으로 막을 수 있게 한다.

• Journal of Positioning, Navigation, and Timing
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• 제10권4호
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• pp.371-377
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• 2021

This research proposes the best combination of tropospheric delay models for Korean Positioning System (KPS). The overall results are based on real observation data of Japanese Quasi-Zenith satellite system (QZSS), whose constellation is similar to the proposed constellation of KPS. The tropospheric delay models are constructed as the combinations of three types of zenith path delay (ZPD) models and four types of mapping functions (MFs). Two sets of International GNSS Service (IGS) stations with the same receiver are considered. Comparison of observation residuals reveals that the ZPD models are more influential to the measurement model rather than MFs, and that the best tropospheric delay model is the combination of GPT3 with 5 degrees grid and Vienna Mapping Function 1 (VMF1). While the bias of observation residual depends on the receivers, it still remains to be further analyzed.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권9호
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• pp.2154-2172
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• 2013

A centralized cognitive radio (CR) network is proposed and its system capacity is studied. The CR network is designed with power control and multi-user scheduling schemes to support best-effort traffics under peak interference power constraints. We provide an analytical framework to quantify its system capacity, taking into account various key factors such as interference constraints, density of primary users, cell radius, the number of CR users, and propagations effects. Furthermore, closed-form formulas are derived for its capacities when only path loss is considered in the channel model. Semi-analytical expressions for the capacities are also given when more realistic channel models that include path loss, shadowing, and small-scale fading are used. The accuracy of the proposed analytical framework is validated by Monte Carlo simulations. Illustrated with a practical example, the provided analytical framework is shown to be useful for the strategic planning of centralized CR networks.

• Journal of applied mathematics & informatics
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• 제17권1_2_3호
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• pp.1-23
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• 2005

The shortest-paths problem is a fundamental problem in graph theory and finds diverse applications in various fields. This is why shortest path algorithms have been designed more thoroughly than any other algorithm in graph theory. A large number of optimization problems are mathematically equivalent to the problem of finding shortest paths in a graph. The shortest-path between a pair of vertices is defined as the path with shortest length between the pair of vertices. The shortest path from one vertex to another often gives the best way to route a message between the vertices. This paper presents an $O(n^2)$ time sequential algorithm and an $O(n^2/p+logn)$ time parallel algorithm on EREW PRAM model for solving all pairs shortest paths problem on circular-arc graphs, where p and n represent respectively the number of processors and the number of vertices of the circular-arc graph.

• 한국생산제조학회지
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• 제22권2호
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• pp.256-262
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• 2013

This paper presents a linear path control algorithm for NeuroMate robot in a skull drilling system. For the path control inverse kinematics of the robot is analyzed and a linear interpolation algorithm is presented. A geometric approach is used for solving inverse kinematic equations for the robot. Four feasible solutions are found through the approach. The approach gives geometric insights for selecting the best solution from the feasible solutions. The presented linear interpolation algorithm computes a next position considering current velocity and remaining distance to the target position. Presented algorithm is implemented and tested in a skull drilling system.