• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2006년도 추계학술대회
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• pp.60-66
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• 2006

This paper presents a new algorithm for the K shortest path problem in a directed network. After a shortest path is produced with Dijkstra algorithm, detouring paths through inward arcs to every vertex of the shortest path are generated. A length of a detouring path is the sum of both the length of the inward arc and the difference between the shortest distance from the origin to the head vertex and that to the tail vertex. K-1 shorter paths are selected among the detouring paths and put into the set of K paths. Then detouring paths through inward arcs to every vertex of the second shortest path are generated. If there is a shorter path than the current Kth path in the set, this path is placed in the set and the Kth path is removed from the set, and the paths in the set is rearranged in the ascending order of lengths. This procedure of generating the detouring paths and rearranging the set is repeated for the K-1 st path of the set. This algorithm can be applied to a problem of generating the detouring paths in the navigation system for ITS and also for vehicle routing problems.

• 경영과학
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• 제25권2호
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• pp.81-88
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• 2008

This paper presents a new algorithm for the K shortest paths problem in a network. After a shortest path is produced with Dijkstra algorithm. detouring paths through inward arcs to every vertex of the shortest path are generated. A length of a detouring path is the sum of both the length of the inward arc and the difference between the shortest distance from the origin to the head vertex and that to the tail vertex. K-1 shorter paths are selected among the detouring paths and put into the set of K paths. Then detouring paths through inward arcs to every vertex of the second shortest path are generated. If there is a shorter path than the current Kth path in the set. this path is placed in the set and the Kth path is removed from the set, and the paths in the set is rearranged in the ascending order of lengths. This procedure of generating the detouring paths and rearranging the set is repeated until the $K^{th}-1$ path of the set is obtained. The computational results for networks with about 1,000,000 nodes and 2,700,000 arcs show that this algorithm can be applied to a problem of generating the detouring paths in the metropolitan traffic networks.

• Journal of the Korean Statistical Society
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• 제29권3호
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• pp.297-306
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• 2000

An efficient method of constructing $textsc{k}$-minimal path sets to evaluate the reliability of a flow network is presented. The network is considered to be in a functioning state if it can transmit a maximum flow which is greater than or equal to a specified amount of flow, $textsc{k}$say, and a $textsc{k}$-minimal path set is a minimal set of branches that satisfies the given flow constraint. In this paper, under the assumption that minimal path sets of the network are known, we generate composite paths by adding only a minimal set of branches at each iteration to get $textsc{k}$-minimal path sets after possibly the fewest composition, and compute maximum flow of composite paths using only minimal path sets. Thereby we greatly reduce the possible occurrence of redundant composite paths throughout the process and efficiently compute the maximum flow of composite paths generated. Numerical examples illustrate the method.

• 정보처리학회논문지A
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• 제8A권2호
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• pp.179-188
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• 2001

We analyze the property of candidate node set in the network graph, and propose an algorithm to decrease shortest path-finding computation time by using multiple dynamic-range queue(MDRQ) structure. This MDRQ structure is newly created for effective management of the candidate node set. The MDRQ algorithm is the shortest path-finding algorithm that varies range and size of queue to be used in managing candidate node set, in considering the properties that distribution of candidate node set is constant and size of candidate node set rapidly change. This algorithm belongs to label-correcting algorithm class. Nevertheless, because re-entering of candidate node can be decreased, the shortest path-finding computation time is noticeably decreased. Through the experiment, the MDRQ algorithm is same or superior to the other label-correcting algorithms in the graph which re-entering of candidate node didn’t frequently happened. Moreover the MDRQ algorithm is superior to the other label-correcting algorithms and is about 20 percent superior to the other label-setting algorithms in the graph which re-entering of candidate node frequently happened.

• International Journal of CAD/CAM
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• 제8권1호
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• pp.45-53
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• 2009

As the point sampling technology evolves rapidly, there has been increasing need in generating tool path from dense point set without creating intermediate models such as triangular meshes or surfaces. In this paper, we present a new tool path generation method from point set using Euclidean distance fields based on Algebraic Point Set Surfaces (APSS). Once an Euclidean distance field from the target shape is obtained, it is fairly easy to generate tool paths. In order to compute the distance from a point in the 3D space to the point set, we locally fit an algebraic sphere using moving least square method (MLS) for accurate and simple calculation. This process is repeated until it converges. The main advantages of our approach are : (1) tool paths are computed directly from point set without making triangular mesh or surfaces and their offsets, and (2) we do not have to worry about no local interference at concave region compared to the other methods using triangular mesh or surface model. Experimental results show that our approach can generate accurate enough tool paths from a point set in a robust manner and efficiently.

• 정보과학회 논문지
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• 제42권1호
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• pp.86-92
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• 2015

레벨 셋 트리는 다차원에 정의된 확률 밀도 함수를 표현하는데 유용하다. 복잡한 데이터의 구조를 트리 형태로 시각화하여 데이터의 형태를 효율적으로 파악할 수 있으며 클러스터링 분석에 효과적으로 이용할 수 있다. 본 논문에서는 미지의 확률 밀도 함수에서 생성된 데이터 샘플로부터 레벨 셋 트리를 생성하는 알고리즘을 제안한다. 제안된 알고리즘은 레벨을 0에서부터 무한대로 증가시키며 밀도 함수의 각 레벨 셋을 추정하고, 이로부터 레벨 셋 트리를 생성한다. 이를 위해 본 논문에서는 one-class 서포트 벡터 머신 (OC-SVM)을 이용하여 직접적으로 레벨 셋을 추정한다. 이때 다양한 레벨 값에 대해 OC-SVM 학습을 반복해야 하는데, OC-SVM 솔루션 path 알고리즘을 통해 빠른 시간 안에 모든 레벨값에 해당하는 레벨 셋를 추정할 수 있다.

• 소성∙가공
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• 제17권7호
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• pp.491-495
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• 2008

Incremental forming path to manufacture a thick concave steel plate using the line array roll set is designed. To find the optimum forming path, the forming processes are simulated by the finite element method. A general-purpose commercial software, MSC MARC is used. A modeling with 8-node hexahedral elastic-plastic solid is performed to predict accurate springback and the analysis process was composed of 18 passes. The proposed forming paths are verified through experiments carried out in the prototype line array roll set. It is found that the process can be successfully applied to the fabrication of the dual curvature ship hull plate.

• 한국시뮬레이션학회논문지
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• 제10권2호
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• pp.61-74
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• 2001

The reliability evaluation of the large scale network becomes very complicate according to the growing size of network. Moreover if the reliability is not constant but follows probability distribution function, it is almost impossible to compute them in theory. This paper studies the network evaluation methods in order to overcome such difficulties. For this an efficient path set algorithm which seeks the path set connecting the start and terminal nodes efficiently is developed. Also, various variance reduction techniques are applied to compute the system reliability to enhance the simulation performance. As a numerical example, a large scale network is given. The comparisons of the path set algorithm and the variance reduction techniques are discussed.

• 한국정보과학회논문지:시스템및이론
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• 제35권8호
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• pp.385-393
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• 2008

사용자가 가능한 센서 가까이에서 이동하는 문제를 최단거리유지 문제(Best Coverage Problem)라 하며, 무선 연결의 안정성을 높이기 위해서 두 개의 센서로부터 최대한 가까이 위치하며 움직이는 이동경로를 차선거리유지 경로(Second Best Coverage Path)라고 한다. 이 논문에서는 센서들의 집합 U와 시작점 s, 끝점 t가 주어질 때, s에서 t까지 이르는 모든 경로 중에서, 가장 가까운 두 개의 센서까지 거리 중 큰 값이 최소가 되는 차선거리유지 경로를 찾는 O(n logn)-시간 알고리즘을 제시하며, 차선거리유지 경로를 따라 움직일 때가 최단거리유지 경로를 따라 움직일 때 보다, 네트워크에의 연결이 보다 안정적임을 보여주는 실험결과도 또한 제시한다.

• 대한전자공학회논문지SD
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• 제47권2호
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• pp.51-59
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• 2010

드모르간 및 재대입 논리변환은 unate gate network (UGN)을 보다 일반적인 balanced inversion parity (BIP) network으로 전환하는데 충분하다. 이러한 회로계층에 대해서도 자세히 논의하고 있다. 우리는 드모르간 및 재대입 논리변환이 경로지연고장 테스트집합을 유지한다는 것을 증명하였다. 본 논문의 결과를 이용하여 함수 z를 구현하는 모든 UGN에서 모든 경로지연고장을 검출하는 상위수준 테스트집합은 함수 z의 어떠한 BIP realization에서도 모든 경로지연고장을 검출한다는 것을 보일 수 있다.