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

• Journal of Korean Society of Transportation
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• v.22 no.5
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• pp.61-73
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• 2004

The efficiency of the real-time route guidance system(RGS) depends largely on the quality of route search algorithms. In this paper, we implement the coarse grid method(CGM) in mathematical programming for finding a good quality route of real-time RGS in large-scale networks. The proposed CGM examines coarser and wider networks as the search phase proceeds, in stead of searching the whole network at once. Naturally, we can significantly reduce computational efforts in terms of search time and memory requirement. We demonstrate the practical effectiveness of the proposed CGM with nationwide real road network simulation.

• Journal of Korean Society of Transportation
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• v.17 no.3
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• pp.73-85
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• 1999

In metropolitan area, intersections having turn Prohibitions are often found and it is important to consider them in path planning. This Paper presents a new path planning method road networks having turn prohibitions. A new road network model is proposed in which an alter-native route for each turn-Prohibition is constructed in off-line using U-turn or P-turn and then Put into road network database. The proposed network model is efficient since it requires no virtual nodes that are usually used in the conventional road networks to represent turns at intersections. In order to find a shortest path with the proposed network, a new shortest path algorithm is proposed. A knot for the turn-Prohibited node is newly defined and is used in comparing the cost of the alternative route with that of the other path.

• The Journal of the Korea Contents Association
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• v.7 no.7
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• pp.1-10
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• 2007

In this paper, we propose an indexing method for efficiently updating current positions of moving objects on road networks. The existing road network models increase update costs when objects move to adjacent road segments because their connectivity is not preserved. We propose an intersection based network model and a new index structure to solve this problem. The proposed intersection based network model preserves network connectivity through splitting road networks to contain intersection nodes always. The proposed index structure In our experiments, we show that our method is about 3 times faster than an existing index structure in terms of update costs.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10a
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• pp.724-726
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• 2004

본 논문에서는 L$_1$평면상에 도로망이 주어져 있어서 여행자들이 그 도로들을 이용하여 더욱 빠르게 이동할 수 있는 가정 하에서 가장 기초적인 기하문제 중에 하나인 두 점 사이의 최단 경로를 찾는 문제를 다룬다. 이 때, 두 점 사이의 거리는 L$_1$ 거리가 아닌 주어진 도로들을 이용하여 두 점 사이를 이동할 때 필요한 최소시간으로 측정한다. 단순한 평면상에서의 최단경로와는 달리 도로망이 설치되어 있는 경우는 그것을 해결하기가 일반적으로 쉽지 않다. 본 논문에서는 도로망이 있는 평면에 대한 깊은 관찰과 이해를 통해 도로망이 설치되어 있는 L$_1$ 평면상에서의 최단경로 문제를 해결하는 효율적인 알고리즘을 제시한다. 덧붙여, 본 논문에서 제시하는 문제 해결 방법은 L$_1$ 평면뿐만 아니라 유클리드 평면에도 어렵지 않게 적용할 수 있으며 보로노이 다이어그램으로의 일반화도 간단하다.

• Journal of Korean Society of Transportation
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• v.17 no.2
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• pp.127-135
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• 1999

Most existing progression bandwidth models maximize the single or multi weighted sum of bandwidths in the both directions to improve traffic mobility on an arterial, but they cannot be applied to general networks. Even though a few models formulating a looped network problem cannot be applied to networks have not loops. Also they have some defects in optimizing phase sequences. Therefore, the objective of this study is to develope a mathematical formulation of the synchronization problem for a general traffic network. The goal is achieved successfully by introducing the signal phasing for each movement and expanding the mixed integer linear programming of MAXBAND. The experiments indicate that the proposed model can formulate the general traffic network problem mere efficiently than any other model. In conclusion, this model may optimize signal time to smooth progression in the general networks.

• 한국도로학회지:도로
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• v.19 no.1
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• pp.15-24
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• 2017

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

• Journal of Korean Society of Transportation
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• v.23 no.1
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• pp.55-66
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• 2005

Association of South East Asian Nations(ASEAN) has recently decided to develop ASEAN Highway Network to connect member countries by road in an attempt to achieve a goal of closer economic integration in the region. This entailed the necessity to newly construct or upgrade some 5,481 km of road sections to make ASEAN Highway Network functional. This study offers haw we can prioritize development of these road sections using the Analytic Hierarchy Process. Particularly, it shows how individual road sections can be prioritized considering the importance of corridor or road group where the individual road section lies. It also develops how values of different evaluation criteria can be compared in the same scale. This new approach can be useful in prioritizing highway development in such cases where candidate road sections are widely scattered around the region, so detailed benefit and cost analysis is practically too demanding to carry out.

• Journal of the Institute of Convergence Signal Processing
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• v.2 no.2
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• pp.7-12
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• 2001

In this paper, an estimation method of hybrid feature was proposed to detect linear feature such as the road network from SAR(synthetics aperture radar) images that include speckle noise. First we considered the mean intensity ratio or the statistical properties of locality neighboring regions to detect linear feature of road. The responses of both methods are combined to detect the entire road network. The purpose of this paper is to extract the segments of road and to mutually connect them according to the identical intensity road from the locally detected fusing images. The algorithm proposed in this paper is to define MRF(markov random field) model of the priori knowledge on the roads and applied it to energy function of interacting density points, and to detect the road networks by optimizing the energy function.