• Proceedings of the Korea Information Processing Society Conference
• /
• 2009.04a
• /
• pp.336-339
• /
• 2009

본 논문에서는 최단 경로 탐색 및 거리 계산의 필요성을 가지고 근사 인덱싱 방법의 후처리 부분을 제안한다. 근사 인덱싱 방법이란 오프라인에서 네트워크 공간상의 객체들을 유클리드 공간 상의 절대 좌표로 사상하여 인덱싱한 후, k-최근접 이웃 질의를 처리하는 방법이다. 그러나 기존 연구는 질의 점으로부터 각 정적 객체까지의 경로를 탐색해주지 않을 뿐만 아니라 착오 기각이 발생한다. 따라서 본 논문에서는 질의 점으로부터 k개의 정적 객체까지의 경로를 효과적으로 탐색할 수 있는 방법을 제안한다. 또한, 이 방법을 통하여 착오 기각 역시 완화시킬 수 있는 방법을 제안한다. 실험을 통하여 제안하는 방법이 기존 경로 탐색 기법들에 비해 노드 탐색 횟수 및 실행 성능이 크게 향상시킨 것으로 나타났다.

• Journal of KIISE:Computer Systems and Theory
• /
• v.29 no.11
• /
• pp.634-639
• /
• 2002

A Shortest Path Algorithm is the method to find the most efficient route among many routes from a start node to an end node. It is based on Labeling methods. In Labeling methods, there are Label-Setting method and Label-Correcting method. Label-Setting method is known as the fastest one among One-to-One shortest path algorithms. But Benjamin[1,2] shows Label-Correcting method is faster than Label-Setting method by the experiments using large road data. Since Graph Growth algorithm which is based on Label-Correcting method is made to find One-to-All shortest path, it is not suitable to find One-to-One shortest path. In this paper, we propose a new One-to-One shortest path algorithm. We show that our algorithm is faster than Graph Growth algorithm by extensive experiments.

• Journal of The Korean Association of Information Education
• /
• v.2 no.2
• /
• pp.252-259
• /
• 1998

Vehicle navigation systems employ a certain route planning algorithm that provides the shortest path between the starting point and the destination point. The performance of a given route planning algorithm is measured through the degree of optimal route selection and the time cost to complete searching an optimal path. In this paper, various route planning algorithms are evaluated through computer simulation based on a real digital map database. Among those algorithms evaluated in this paper, the Modified Bi-directional A${\ast}$ algorithm is found to be the best algorithm for use in vehicle navigation systems.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.17 no.5
• /
• pp.654-659
• /
• 2007

This paper proposes the effective method for classifying the working spates and modelling the environments, when complex working environments of AGVS(Automated Guided Vehicle System) ate changed. And, we propose the shortest path searching algorithm using the A* algorithm of graph search method. Also, we propose the methods for finding each AGV's travel time of shortest path. Finally, a simple example is included for visualizing the feasibility of the proposed methods.

• Journal of Korean Society for Geospatial Information Science
• /
• v.10 no.1 s.19
• /
• pp.59-66
• /
• 2002

The rapid change of industrial structure causes to increase distribution cost and requires necessity of physical distribution system urgently. Traffic situation is getting extremely worse and traffic jam has led to increasing expense of physical distribution delivery which dominates 20% of distribution cost. In this situation, the shortest and most suitable path search system is required by modern people who must waste a lot of time for moving with a car or on the street as well as many companies. for these reasons, we developed the shortest-path-searching system applying the dijkstra algorithm which is one of the effective shortest path algorithm to GIS, and it was constructed by considering realistic urban traffic and the pattern of street in a physical situation. Also, this system was developed to be updated weight data automatically, considering the dynamic change of traffic situation such as a traffic information service which will be served in real time. Finally, we designed this system to serve on web by using MapObjects IMS.

• The KIPS Transactions:PartB
• /
• v.18B no.3
• /
• pp.157-164
• /
• 2011

This paper presents a fast and scalable re-routing algorithm that adapts to dynamically changing networks. The proposed algorithm integrates Dijkstra's shortest path algorithm with the genetic algorithm. Dijkstra's algorithm is used to define the predecessor array that facilitates the initialization process of the genetic algorithm. After that, the genetic algorithm re-searches the optimal path through appropriate genetic operators under dynamic traffic situations. Experimental results demonstrate that the proposed algorithm produces routes with less traveling time and computational overhead than pure genetic algorithm-based approaches as well as the standard Dijkstra's algorithm for large-scale networks.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.10 no.11
• /
• pp.2002-2007
• /
• 2006

The path search method in the telematics system should consider traffic flow of the roads as well as the shortest time because the optimal path with minimized travel time could be continuously changed by the traffic flow. The existing path search methods are not able to cope efficiently with the change of the traffic flow. The search method to use traffic information also needs more computation time than the existing shortest path search. In this paper, a method for efficiency improvement of path search is implemented and its performance is evaluated. The method employs the fixed grid for adjustable heuristic to traffic flow. Moreover, in order to simplify the computation of estimation values, it only adds graded decimal values instead of multiplication operation of floating point numbers with due regard to the gradient between a departure and a destination. The results obtained from the experiments show that it achieves the high accuracy and short execution time as well.

• Proceedings of the Korean Information Science Society Conference
• /
• 1999.10a
• /
• pp.183-185
• /
• 1999

주행 경로 안내는 최근 국내에서도 활발히 연구되고 있는 지능형 교통 시스템(ITS)의 주요 기능 중 하나이다. 주행 경로 안내를 위해서는 대규모 도로망에서 신속하게 경로를 찾는 방법과 찾은 경로를 음성 또는 기호로 운전자에게 효율적으로 안내하는 방법등이 필요하다. 본 논문에서는 도로망의 계층성을 휴리스틱 정보로 활용하여 최단시간 경로를 효율적으로 찾는 방법을 제안한다. 제안된 방법은 고속국도, 국도 등의 고속 주행용 도로만으로 소규모 상위 계층 도로망을 만들고 이를 기존 도로망에 덧붙이는 방식으로 통합한다. 이 통합망에 상위 계층 도로망을 우선적으로 찾도록 구성한 A* 알고리즘을 수행하여 최단시간 경로를 찾는다. 또 경로 탐색용 그래프가 디스크에 저장된 경우에, 디스크 접근을 최적화하기 위한 데이터베이스 설계 및 디스크 접근 방법을 기술한다. 제안된 방법의 효율성을 검증하기 위해 서울시 도로망 데이터를 이용하여 실험한 결과, 제안된 방법을 통해 경로 탐색 소요 시간, 디스크 입출력 회수, 메모리 사용량 등을 75%이상 줄일 수 있었다.

• The Transactions of the Korea Information Processing Society
• /
• v.13 no.6
• /
• pp.269-277
• /
• 2024

With the advancement of modern IT technologies, the operation of autonomous vehicles is becoming a reality, and route planning is essential for this. Generally, route planning involves proposing the shortest path to minimize travel distance and the quickest path to minimize travel time. However, the quality of these routes depends on the topological characteristics of the road network graph. If the connectivity structure of the road network is not rational, there are limits to the performance improvement that routing algorithms can achieve. Real drivers consider psychological factors such as the number of turns, surrounding environment, traffic congestion, and road quality when choosing routes, and they particularly prefer routes with fewer turns. This paper introduces a simple path algorithm that seeks routes with the fewest turns, in addition to the traditional shortest distance and quickest time routes, to evaluate the characteristics of road networks. Using this simple path algorithm, we compare and evaluate the connectivity characteristics of road networks in 20 major cities worldwide. By analyzing these road network characteristics, we can identify the strengths and weaknesses of urban road networks and develop more efficient and safer route planning algorithms. This paper comprehensively examines the quality of road networks and the efficiency of route planning by analyzing and comparing the road network characteristics of each city using the proposed simple path algorithm.

• Proceedings of the KIEE Conference
• /
• 2008.07a
• /
• pp.1837-1838
• /
• 2008

최단 경로란 유향(有向) 또는 무향(無向) 그래프에서 어떤 두 점 사이를 맺는 유향 또는 무향 경로 중 가장 짧은 것, 즉 가지의 길이 합을 최소로 하는 것을 구하는 문제. 그래프가 평면 접속인 경우에는 쌍대(雙對) 그래프의 최대 흐름을 구하는 문제와 등가이다. 본 논문에서는 최단 경로 문제를 풀기 위하여 Dijkstra의 장점은 살리고 단점을 보완하는 방향성을 가지는 Dijkstra 알고리즘을 제안하였다. 사례연구를 통하여 제안한 알고리즘은 출발점에서 도착점까지 최단 경로를 빠른 시간에 찾아가는 것을 보였다.