• 전자공학회논문지SC
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• 제43권6호
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• pp.1-8
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• 2006

이동로봇의 경로 설정과 장애물 회피에 관한 문제는 이동로봇을 제어하기 위한 기본적인 문제로서 지금까지 많은 연구가 진행되어 오고 있다. 다양한 센서들로부터 얻어지는 정보는 로봇이 진행하기 위한 경로에 대한 결정과 장애물에 대한 정보를 제공해준다. 대부분의 연구들은 제한 조건이 존재하는 경우에서 그 상황에 알맞은 방법들이 대부분이며, 다른 상황을 해결하기에는 어려움이 있다. 또한, 최적화된 경로에 대한 좋은 결과를 만들기 위해서는 복잡한 계산 과정을 통해서 시간 지연이 발생하게 된다. 이와 같은 처리 방법은 움직이는 장애물의 회피와 같이 빠른 처리를 필요로 하는 상황에서 단점으로 작용한다. 본 논문에서는 장애물과 이동 가능한 경로들의 영역을 작은 영역들이 분포하는 공간으로 변형하고 이와 같이 구성된 공간에서 밀도와 연결 상태를 통해 이동 로봇이 진행 할 수 있는 최단 경로를 결정하는 방법을 제안한다. 제안된 방법에서 작은 영역들은 자신의 번호를 가지게 되며, 주변 영역들의 개수를 통해 이동 경로를 결정하게 된다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권4호
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• pp.1256-1275
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• 2014

As one of the new self-organizing and self-configuration broadband networks, wireless mesh networks are being increasingly attractive. In order to solve the load balancing problem in wireless mesh networks, this paper proposes a novel multi-path routing algorithm based on clustering (Cluster_MMesh) for wireless mesh networks. In the clustering stage, on the basis of the maximum connectivity clustering algorithm and k-hop clustering algorithm, according to the idea of maximum connectivity, a new concept of node connectivity degree is proposed in this paper, which can make the selection of cluster head more simple and reasonable. While clustering, the node which has less expected load in the candidate border gateway node set will be selected as the border gateway node. In the multi-path routing establishment stage, we use the intra-clustering multi-path routing algorithm and inter-clustering multi-path routing algorithm to establish multi-path routing from the source node to the destination node. At last, in the traffic allocation stage, we will use the virtual disjoint multi-path model (Vdmp) to allocate the network traffic. Simulation results show that the Cluster_MMesh routing algorithm can help increase the packet delivery rate, reduce the average end to end delay, and improve the network performance.

• Journal of applied mathematics & informatics
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• 제32권1_2호
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• pp.255-266
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• 2014

For a connected graph G = (V,E) of order at least two, a set S of vertices of G is a monophonic set of G if each vertex v of G lies on an x - y monophonic path for some elements x and y in S. The minimum cardinality of a monophonic set of G is the monophonic number of G, denoted by m(G). Certain general properties satisfied by the monophonic sets are studied. Graphs G of order p with m(G) = 2 or p or p - 1 are characterized. For every pair a, b of positive integers with $2{\leq}a{\leq}b$, there is a connected graph G with m(G) = a and g(G) = b, where g(G) is the geodetic number of G. Also we study how the monophonic number of a graph is affected when pendant edges are added to the graph.

• 한국해양공학회지
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• 제23권6호
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• pp.146-155
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• 2009

This paper considers the path tracking problem in a horizontal plane for underactuated (or non-holonomic) autonomous underwater vehicles (AUVs). Underwater mapping has been an important mission for AUVs. Recently, underwater docking has also become a main research field of AUVs. These kinds of missions basically require accurate attitude and trajectory control performance. However, the non-holonomic problem should be solved to achieve accurate path tracking for the torpedo-type of AUVs. In this paper, resolved motion and acceleration control (RMAC) is considered as a path tracking controller for an underactuated torpedo-shaped AUV, ISiMi. A set of numerical simulations is carried out to illustrate the effectiveness of the proposed RMAC scheme, and experimental data with ISiMi100 and discussions are presented.

• 대한전자공학회논문지TC
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• 제40권12호
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• pp.38-45
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• 2003

최근에 글로벌 QoS 라우팅방식의 약점을 개선하려는 노력으로 로컬 QoS 라우팅 방식이 제시되었다. 글로벌 라우팅과는 다르게 로컬 QoS 라우팅에서는 라우터간의 상태교환을 수행하지 않고 virtual capacity를 사용하여 라우터가 독자적으로 라우팅을 수행한다. 로컬 QoS 라우팅에서는 소스와 목적간의 경로가 효과적으로 선택되어야만 좋은 성능을 보장받을 수 있다. 본 논문에서는 효과적인 경로 선택을 위하여 몇몇의 휴리스틱을 제시하고 이를 활용한 경로 선택 알고리즘을 제안하였다. 제안된 알고리즘은 시뮬레이션과 함께 분석되었으며 경로선정방식에 따라 로컬 QoS 라우팅의 성능이 매우 큰 영향을 받는다는 것을 확인하였다.

• 대한전기학회논문지:시스템및제어부문D
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• 제49권10호
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• pp.582-590
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• 2000

A fast optimal path planning algorithm using the analog Cellular Nonlinear Circuits(CNC) is proposed. The analog circuits based optimal path planning is very useful since most of the optimal path planning problems require real time computation. There has already been a previous study to implement the dynamic programming with analog circuits. However, it could not be applied for the practically large size of problems since the algorithm employs the mechanism of reducing its input current/voltage by the amount of cost, which causes outputs of distant cells to become zero. In this study, a subgoal-based dynamic programming algorithm to compute the optimal path is proposed. In the algorithm, the optimal paths are computed regardless of the distance between the starting and the goal points. It finds subgoals starting from the starting point when the output of the starting cell is raised from its initial value. The subgoal is set as the next initial position to find the next subgoal until the final goal is reached. The global optimality of the proposed algorithm is discussed and two different kinds of simulations have been done for the proposed algorithm.

• 한국컴퓨터정보학회논문지
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• 제19권5호
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• pp.89-98
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• 2014

본 논문은 NP-난제 문제로 알려진 단일모델 단방향 조립라인 균형문제에 대해 휴리스틱 알고리즘을 제안하였다. 조립라인 균형문제는 주로 메타휴리스틱 방법들을 적용하고 있는 추세이다. 제안된 알고리즘은 최종제품이 생산될 때까지 가장 많은 공정으로 조립되는 경로를 주경로로 설정하고, 주경로를 따라가면서 각 작업자에게 순환시간 조건을 만족하는 작업량을 배정하는 군집화 알고리즘을 제안하였다. 제안된 알고리즘은 최소의 작업자수를 결정하고, 순환시간도 단축시키는 결과를 얻었다. 9개의 다양한 실험 데이터에 제안된 주경로 군집화 휴리스틱 알고리즘을 적용한 결과 메타휴리스틱 방법들에 비해 보다 좋은 성능을 갖고 있음을 보였다.

• 한국정보과학회논문지:시스템및이론
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• 제36권1호
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• pp.40-51
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• 2009

그래프 G의 쌍형 다대다 k-서로소인 경로 커버(쌍형 k-DPC)는 k개의 서로 다른 소스-싱크 쌍을 연결하며 그래프에 있는 모든 정점을 지나는 k개의 서로소인 경로 집합이다. 이 논문에서는 재귀원형군 G($cd^m$,d), $d{\geq}3$과 토러스에서 서로소인 경로 커버를 고려하여, 이분 그래프가 아니고 분지수가 $\delta$인 재귀원형군과 토러스는 고장 요소(정점이나 에지)가 f개 이하일 때 $f+2k{\leq}{\delta}-1$을 만족하는 임의의 f, $k{\geq}1$에 대하여 쌍형 k-DPC를 가짐을 보인다.

• 한국환경과학회지
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• 제27권11호
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• pp.1073-1081
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• 2018

In this study, an operational data set was analysed by establishing a path model to figure out the actual cause-effect relationship of a wastewater treatment plant (WWTP); in particular, for the effluent concentrations of T-N and T-P. To develop the path models, data sets of operational records including effluent concentrations and operational factors were obtained from a field scale WWTP of $680,000m^3$ of treatment capacity. The models showed that the relationship networks with the correlation coefficients between variables for objective expressions indicated the strength of each relationship. The suggested path models were verified according to whether the analyzation results matched known theories well, but sophisticated minute theoric relationships could not be cropped out distinctly. This indicates that only a few paths with strong theoric casual relationships were represented as measured data due to the high non-linearity of the mechanism of the removal process in a biological wastewater treatment.

• 대한간호학회지
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• 제52권4호
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• pp.363-377
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• 2022

Purpose: This study aimed to test a hypothetical model of Korean nurses' patient safety management activities using meta-analytic path analysis. Methods: A systematic review, meta-analysis, and meta-analytic path analysis were conducted following the PRISMA and MOOSE guidelines. Seventy-four studies for the meta-analysis and 92 for the meta-analytic path analysis were included. The R software program (Version 3.6.3) was used for data analysis. Results: Four variables out of 49 relevant variables were selected in the meta-analysis. These four variables showed large effect sizes (ESr = .54) or median effect sizes (ESr = .33~.40) with the highest k (number of studies) in the individual, job, and organizational categories. The hypothetical model for the meta-analytic path analysis was established using these variables and patient safety management activities. Twelve hypothetical paths were set and tested. Finally, the perception of the importance of patient safety management and patient safety competency directly affected patient safety management activities. In addition, self-efficacy, the perception of the importance of patient safety management, patient safety competency, and patient safety culture, indirectly affected patient safety management activities. Conclusion: Self-efficacy, the perception of the importance of patient safety management, patient safety competency, and the organization's patient safety culture should be enhanced to improve nurses' patient safety management activities.