• 한국통신학회논문지
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• 제21권9호
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• pp.2385-2401
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• 1996

ATM망의 단대단 통신로 추적관리를 위한 모델과 추적 알고리즘을 제시하고 시뮬레이션을 통하여 이 알고리즘의 성능을 분석하였다. 제안 모델은 TINA(Telecommunication Information Networking Architecture)구조와 ODP(Open Distributed Processing)의 계산객체를 기본으로 하였다. 계산객체는 ATM 라우팅 기능을 수행하는 계산객체와 경로 추적을 수행하는 계산객체로 구성하였으며, 이들간의 관계를 기본으로 하는 수행절차를 설정하였다. 이 수행 절차는 연결된 ATM 경로를 추적함으로써 단대단 통신로를 식별하고 이러한 통신로 식별 데이타를 수집하는 과정으로 수행된다. 제안한 단대단 통신로 추적관리는 NML(Networking Management Level) 관점에서 수행되며, 이를 위한 알고리즘으로 실시간 속성과 추적기능의 무결성을 고려하여 broadeasting-with-synchronized-control과 GTM(Global Ticket Method)을 제안하였다.

• 경영과학
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• 제19권1호
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• pp.55-66
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• 2002

Given a directed network, a designated arc, and lowers and upper bounds for the distance of each arc, the preprocessing shortest path problem Is a decision problem that decides whether there is some choice of distance vector such that the distance of each arc honors the given lower and upper bound restriction, and such that the designated arc is on some shortest path from a source node to a destination notre with respect to the chosen distance vector. The preprocessing shortest path problem has many real world applications such as communication and transportation network management and the problem is known to be NP-complete. In this paper, we develop an algorithm that solves the problem using the structural properties of shortest paths.

• 한국경영과학회지
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• 제16권2호
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• pp.103-117
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• 1991

Two important sensitivity issues over shortest path problems have been discussed. One is the problem of updating shortest paths when nodes are added and when the lengths of some arcs are increased or decreased. The other is the problem of calculating arc tolerances, that is the maximum increase of decrease in the length of a single arc without changing a given optimal tree. In this paper, assuming that there exists a parameter of interest whose perturbation causes the simultaneous changes in arc lengths, we find the invariance condition on these simultaneous changes such that the shortest path between two specified nodes remains unchanged.

• 한국경영과학회지
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• 제20권1호
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• pp.35-54
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• 1995

Routing in ATM network is set up by combination of both virtual path routing and virtual channel routing. While virtual channel is similar concept to virtual circuit of data networks, virtual path is a special concept which is not used in traditional data networks. Virtual path can rearrange in structure and size by simply changing virtual path routing tables and giving the network the capability to eash allocate network resources according to the demand needs. This paper provides reconfiguration models of virtual path network which give the bandwidth of link and the routing path for each traffic class. The reconfiguration models are network optimization problems of multicommodity network flow type. The numerical examples are also included.

• 디지털산업정보학회논문지
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• 제10권3호
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• pp.197-205
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• 2014

In applications of adaptive noise control or active noise control, the presence of a transfer function in the secondary path following the adaptive controller and the error path, been shown to generally degrade the performance of the Least Mean Square (LMS) algorithm. Thus, the convergence rate is lowered, the residual power is increased, and the algorithm can become unstable. In general, in order to solve these problems, the filtered-x LMS (FX-LMS) type algorithms can be used. But these algorithms have slow convergence speed and weakness in the environment that the secondary path and error path are varied. Therefore, I present the new algorithm called the "Bi-directional Filtered-x (BFX) LMS" algorithm with nearly equal computation complexity. Through experimental study, the proposed BFX-LMS algorithm has better convergence speed and better performance than the conventional FX-LMS algorithm, especially when the secondary path or error path is varied and the impulsive disturbance is flow in.

• Management Science and Financial Engineering
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• 제12권2호
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• pp.87-110
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• 2006

In a hierarchical road network, all roads can be classified according to their attributes such as speed limit, number of lanes, etc. By splitting the whole road network into the subnetworks of the highlevel and low-level roads, we can reduce the size of the network to be calculated at once, and find a path in the way that drivers usually adopt when searching out a travel route. To exploit the hierarchical property of road networks, we define a convenient path and propose an algorithm for finding convenient paths. We introduce a parameter indicating the driver's tolerance to the difference between the length of a convenient path and that of a shortest convenient path. From this parameter, we can determine how far we have to search for the entering and exiting gateway. We also propose some techniques for reducing the number of pairs of entries and exits to be searched in a road network. A result of the computational experiment on a real road network is given to show the efficiency of the proposed algorithm.

• Journal of Forest and Environmental Science
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• 제37권3호
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• pp.260-268
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• 2021

This study was conducted to grasp users' preferences and behavior of forest paths and to provide basic data for forest path construction in the future. Among forest path users, males and females over 20 years old were surveyed on forest path preferences, motives for visiting, using time and distance, companions, and sources for obtaining information on forest paths. A total of 587 people participated in the questionnaire, and cross-analysis was conducted simultaneously using the SPSS statistical program. In analyzing the preference of forest paths, it was found that male and the general public preferred trekking path for activities while female and foresters preferred forest path for relaxation and healing (p<0.05). As for the motives for visiting forest paths, the response that they visited for a walk/rest was the highest in gender, occupation, and age group. As for the number of annual visits, less than 5 was the highest in overall, and foresters tended to visit forest path more often than the general public, and the number of visits to the forest paths increased with age (p<0.01). The most common route to acquire information about forest paths is the Internet, while the Internet use is relatively low in those over 60s (p<0.05). The response ratio of accompanying their family in visiting forest paths were the highest, while the response in their 20s and 60s was the most in accompanying their friends (p<0.05).

• 경영과학
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• 제15권2호
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• pp.229-237
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• 1998

This paper presents a new algorithm for the K Shortest Paths Problem which is developed with a Double Shortest Arborescence and an inward arc breaking method. A Double Shortest Arborescence is made from merging a forward shortest arborescence and a backward one with Dijkstra algorithm. and shows us information about each shorter path to traverse each arc. Then K shorter paths are selected in ascending order of the length of each short path to traverse each arc, and some paths of the K shorter paths need to be replaced with some hidden shorter paths in order to get the optimal paths. And if the cross nodes which have more than 2 inward arcs are found at least three times in K shorter path, the first inward arc of the shorter than the Kth shorter path, the exposed path replaces the Kth shorter path. This procedure is repeated until cross nodes are not found in K shorter paths, and then the K shortest paths problem is solved exactly. This algorithm are computed with complexity o($n^3$) and especially O($n^2$) in the case K=3.

• 한국경영과학회지
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• 제16권1호
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• pp.1-12
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• 1991

This paper studies an optimal algorithm for the Maximum Origin-Destination Flor Path (MODFP) in an acyclic transportation network. We define a Pseudo-Flow each are so that it can give an upper bound to the total flow of a given path. And using the K-th Shortest Path algorithm we obtain upper bound of MODF which is decreasing as the number of searched path grows. Computational Complexity of optimal algorithm is O(K + m) $n_{2}$), K being the total number of searched path. We proved that the problem complexity of finding MODFP in an acyclic network is NP-hard, showing that the-satisfiability problem can be polynomialy reduced to this problem. And we estimated the average of the number K as being (m/n)$^{1,08}$ Exp (0.00689gm) from the computational experiments.

• 산업경영시스템학회지
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• 제34권3호
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• pp.90-96
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• 2011

Finding the critical path (or the longest path) on acyclic directed graphs, which is well-known as PERT/CPM, the ambiguity of each acr's length can be modeled as a range or an interval, in which the actual length of arc may realize. In this case, the min-max regret criterion, which is widely used in the decision making under uncertainty, can be applied to find the critical path minimizing the maximum regret in the worst case. Since the min-max regret critical path problem with the interval arc's lengths is known as NP-hard, this paper proposes a heuristic algorithm to diminish the maximum regret. Then the computational experiments shows the proposed algorithm contributes to the improvement of solution compared with the existing heuristic algorithms.