• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.843-845
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• 2003

Shortest Path Problems are among the most studied network flow optimization problems, with interesting applications in various fields. One such field is the route determination service, where various kinds of shortest path problems need to be solved in location-based service. Our research aim is to propose a route technique in real-time locationbased service (LBS) environments according to user’s route preferences such as shortest, fastest, easiest and so on. Turn costs modeling and computation are important procedures in route planning. There are major two kinds of cost parameters in route planning. One is static cost parameter which can be pre-computed such as distance and number of traffic-lane. The other is dynamic cost parameter which can be computed in run-time such as number of turns and risk of congestion. In this paper, we propose a new cost modeling method for turn costs which are traditionally attached to edges in a graph. Our proposed route determination technique also has an advantage that can provide service interoperability by implementing XML web service for the OpenLS route determination service specification. In addition to, describing the details of our shortest path algorithms, we present a location-based service system by using proposed routing algorithms.

• 한국국방경영분석학회지
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• 제18권2호
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• pp.140-150
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• 1992

In this paper, we consider the shortest path problem of a Robot car moving in a workspace which consists of some obstacles. The motion of the Robot car is considered to have initial and final directions with some restrictions in the curvature of the path. At first we consider the problem in the case of having no obstacles and we give an analytical solution. Then wre present an algorithm to find a feasible path in the case of having obstacles and a method to improve this feasible path into a minimal path. Some computational results using Graph theory and Linear programming have been included.

• 한국정보처리학회논문지
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• 제7권6호
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• pp.1778-1784
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• 2000

We consider the weighted shortest path updating problem, that is, the problem to reconstruct the weighted shortest paths in response to topology change of the network. This appear proposes a distributed algorithms that reconstructs the weighted shortest paths after several processors and links are added and deleted. its message complexity and ideal-time complexity are O(p$^2$+q+n') and O(p$^2$+q+n') respectively, where n' is the number of processors in the network after the topology change, q is the number of added links, and p is the total number of processors in he biconnected components (of the network before the topology change) including the deleted links or added links.

• 한국ITS학회 논문지
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• 제4권3호
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• pp.9-22
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• 2005

교통망에서 경로의 총 통행비용은 통행비용과 인지비용으로 구분된다. 출발지와 도착지간에 상이하게 인지되는 비용을 고려하여 경로를 탐색하는 것은 전체경로를 열거해야 하는 문제 때문에 현실 적용에 한계가 있다. 따라서 현재 활용되고 있는 첨단교통정보체계(ATIS)에서 경로정보를 제공할 때 통행비용 만을 고려하여 경로를 탐색하는 기법을 적용하는 것이 일반적이다. 본 연구는 경로열거문제 없이 상이한 링크인지비용을 반영하는 최적 및 K 경로탐색기법을 제안한다. 이를 위해 링크를 경로의 최소단위로 정의하고, 따라서 두 링크의 비교가 경로의 비교로 확대되는 링크표지기반경로탐색기법을 활용하며, 도착지를 기반으로 후방향 최적링크인지경로트리를 구축한 후 출발지기반으로 전방향 최적의 링크총비용 경로트리를 구축하는 수식과 알고리즘을 제안한다.

• 한국컴퓨터정보학회논문지
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• 제17권12호
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• pp.199-207
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• 2012

본 논문에서는 사진에 포함된 위치정보를 이용하여 최단경로 알고리즘을 적용한 최적화된 경로를 설정할 수 있는 서비스를 제안하였으며 제안한 서비스를 제공하기 위한 시스템을 설계 및 구현하였다. 사진 안에 있는 EXIF 정보에 포함된 GPS정보를 추출하여 출발지점, 경유지점, 도착지점을 설정한 후 설정된 경로정보에 최단경로 알고리즘(shortest path algorithm)을 적용하여 최적화된 경로를 탐색한다. 구해진 최적화된 경로정보는 야후 맵 API를 활용하여 웹 지도상에 표시된다. 이를 위해 사진 속 위치정보 추출방법, 최단경로 알고리즘을 활용한 경로 정렬(sort) 방법 그리고 야후 맵 API를 이용한 이용자 UI를 활용하여 경로탐색 시스템을 설계하고 이를 바탕으로 GPS정보가 있는 사진 파일을 이용한 최적화된 경로탐색 시스템을 구현하였다.

• Journal of Communications and Networks
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• 제17권4호
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• pp.384-393
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• 2015

This paper proposes an insect behavior-inspired routing algorithm for large-scale wireless mesh networks. The proposed algorithm is adapted from the behavior of an insect called Bombyx mori, a male silkmoth. Its unique behavior is its flying technique to find the source of pheromones. The algorithm consists of two steps: the shortest-path algorithm and the zigzag-path algorithm. First, the shortest-path algorithm is employed to transmit data. After half of the total hops, the zigzag-path algorithm, which is based on the movement of the male B. mori, is applied. In order to adapt the biological behavior to large-scale wireless mesh networks, we use a mesh topology for implementing the algorithm. Simulation results show that the total energy used and the decision time for routing of the proposed algorithm are improved under certain conditions.

• Journal of Communications and Networks
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• 제4권3호
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• pp.246-255
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• 2002

Constrained minimum Steiner tree (CMST) problem is a key issue in multicast routing with quality of service (QoS) support. Bounded shortest path algorithm (BSMA) has been recognized as one of the best algorithms for the CMST problem due to its excellent cost performance. This algorithm starts with a minimumdelay tree, and then iteratively uses a
-shortest-path (KSP) algorithm to search for a better path to replace a “superedge” in the existing tree, and consequently reduces the cost of the tree. The major drawback of BSMA is its high time complexity because of the use of the KSP algorithm. For this reason, we investigate in this paper the possibility of more efficient implementations of BSMA by using different methods to locate the target path for replacing a superedge. Our experimental results indicate that our methods can significantly reduce the time complexity of BSMA without deteriorating the cost performance.

• Journal of Information Processing Systems
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• 제7권2호
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• pp.241-260
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• 2011

In earlier days, most of the data carried on communication networks was textual data requiring limited bandwidth. With the rise of multimedia and network technologies, the bandwidth requirements of data have increased considerably. If a network link at any time is not able to meet the minimum bandwidth requirement of data, data transmission at that path becomes difficult, which leads to network congestion. This causes delay in data transmission and might also lead to packet drops in the network. The retransmission of these lost packets would aggravate the situation and jam the network. In this paper, we aim at providing a solution to the problem of network congestion in mobile ad hoc networks [1, 2] by designing a protocol that performs routing intelligently and minimizes the delay in data transmission. Our Objective is to move the traffic away from the shortest path obtained by a suitable shortest path calculation algorithm to a less congested path so as to minimize the number of packet drops during data transmission and to avoid unnecessary delay. For this we have proposed a protocol named as Congestion Aware Selection Of Path With Efficient Routing (CASPER). Here, a router runs the shortest path algorithm after pruning those links that violate a given set of constraints. The proposed protocol has been compared with two link state protocols namely, OSPF [3, 4] and OLSR [5, 6, 7, 8].The results achieved show that our protocol performs better in terms of network throughput and transmission delay in case of bulky data transmission.

• 대한전자공학회논문지TC
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• 제47권8호
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• pp.53-60
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• 2010

본 논문은 무선센서 망에서 소스 노드와 모바일 싱크 노드 간 데이터 전송경로를 효율적으로 관리하는 방법을 제안한다. 제안하는 방법은 최단거리 전송경로를 보장하며, 기존에 형성되었던 경로를 최대한 이용함으로써 경로재설정을 위한 비용을 줄일 수 있다. 실험 결과는 제안하는 방법이 기존 대표적 경로재설정 방법인 CODE와 EADA에 비해 경로 재설정 비용을 약 60% 감소시켰음을 보여준다.

• 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.