• Title/Summary/Keyword: Shortest distance

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A Combined Heuristic Algorithm for Preference-based Shortest Path Search (선호도 기반 최단경로 탐색을 위한 휴리스틱 융합 알고리즘)

  • Ok, Seung-Ho;Ahn, Jin-Ho;Kang, Sung-Ho;Moon, Byung-In
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.47 no.8
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    • pp.74-84
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    • 2010
  • In this paper, we propose a preference-based shortest path algorithm which is combined with Ant Colony Optimization (ACO) and A* heuristic algorithm. In recent years, with the development of ITS (Intelligent Transportation Systems), there has been a resurgence of interest in a shortest path search algorithm for use in car navigation systems. Most of the shortest path search algorithms such as Dijkstra and A* aim at finding the distance or time shortest paths. However, the shortest path is not always an optimum path for the drivers who prefer choosing a less short, but more reliable or flexible path. For this reason, we propose a preference-based shortest path search algorithm which uses the properties of the links of the map. The preferences of the links are specified by the user of the car navigation system. The proposed algorithm was implemented in C and experiments were performed upon the map that includes 64 nodes with 118 links. The experimental results show that the proposed algorithm is suitable to find preference-based shortest paths as well as distance shortest paths.

A study on pedestrian path search based on the shortest distance algorithm using Map API (Map API를 활용한 최단 거리 알고리즘 기반 보행자 경로 탐색 연구)

  • Jeon, Sung-woo;Kim, Yunbae;Kim, Junyoung;Park, Seonyoung;Jung, Heo-kyung
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2022.10a
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    • pp.219-221
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    • 2022
  • In recent summer, as it is concentrated, even in mountainous areas, flooding and flooding cause casualties in pedestrian evacuation situations. To compensate for this, a system that detects the occurrence of flooding and allows pedestrians to evacuate safely is required. Therefore, in this paper, we propose a research on pedestrian path search based on the shortest distance algorithm using Map API. The pedestrian route search system outputs a map using the T Map API, selects nearby buildings as shelters, and stores data. A shelter close to the pedestrian's current location is selected, and the shortest route is output and the distance and time are provided. If there is a problem with the current route during evacuation, another shelter route is provided from the current location. Therefore, it is thought that the pedestrian route search evacuation system proposed in this paper will prevent accidents during evacuation.

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Intelligent Optimal Route Planning Based on Context Awareness (상황인식 기반 지능형 최적 경로계획)

  • Lee, Hyun-Jung;Chang, Yong-Sik
    • Asia pacific journal of information systems
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    • v.19 no.2
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    • pp.117-137
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    • 2009
  • Recently, intelligent traffic information systems have enabled people to forecast traffic conditions before hitting the road. These convenient systems operate on the basis of data reflecting current road and traffic conditions as well as distance-based data between locations. Thanks to the rapid development of ubiquitous computing, tremendous context data have become readily available making vehicle route planning easier than ever. Previous research in relation to optimization of vehicle route planning merely focused on finding the optimal distance between locations. Contexts reflecting the road and traffic conditions were then not seriously treated as a way to resolve the optimal routing problems based on distance-based route planning, because this kind of information does not have much significant impact on traffic routing until a a complex traffic situation arises. Further, it was also not easy to take into full account the traffic contexts for resolving optimal routing problems because predicting the dynamic traffic situations was regarded a daunting task. However, with rapid increase in traffic complexity the importance of developing contexts reflecting data related to moving costs has emerged. Hence, this research proposes a framework designed to resolve an optimal route planning problem by taking full account of additional moving cost such as road traffic cost and weather cost, among others. Recent technological development particularly in the ubiquitous computing environment has facilitated the collection of such data. This framework is based on the contexts of time, traffic, and environment, which addresses the following issues. First, we clarify and classify the diverse contexts that affect a vehicle's velocity and estimates the optimization of moving cost based on dynamic programming that accounts for the context cost according to the variance of contexts. Second, the velocity reduction rate is applied to find the optimal route (shortest path) using the context data on the current traffic condition. The velocity reduction rate infers to the degree of possible velocity including moving vehicles' considerable road and traffic contexts, indicating the statistical or experimental data. Knowledge generated in this papercan be referenced by several organizations which deal with road and traffic data. Third, in experimentation, we evaluate the effectiveness of the proposed context-based optimal route (shortest path) between locations by comparing it to the previously used distance-based shortest path. A vehicles' optimal route might change due to its diverse velocity caused by unexpected but potential dynamic situations depending on the road condition. This study includes such context variables as 'road congestion', 'work', 'accident', and 'weather' which can alter the traffic condition. The contexts can affect moving vehicle's velocity on the road. Since these context variables except for 'weather' are related to road conditions, relevant data were provided by the Korea Expressway Corporation. The 'weather'-related data were attained from the Korea Meteorological Administration. The aware contexts are classified contexts causing reduction of vehicles' velocity which determines the velocity reduction rate. To find the optimal route (shortest path), we introduced the velocity reduction rate in the context for calculating a vehicle's velocity reflecting composite contexts when one event synchronizes with another. We then proposed a context-based optimal route (shortest path) algorithm based on the dynamic programming. The algorithm is composed of three steps. In the first initialization step, departure and destination locations are given, and the path step is initialized as 0. In the second step, moving costs including composite contexts into account between locations on path are estimated using the velocity reduction rate by context as increasing path steps. In the third step, the optimal route (shortest path) is retrieved through back-tracking. In the provided research model, we designed a framework to account for context awareness, moving cost estimation (taking both composite and single contexts into account), and optimal route (shortest path) algorithm (based on dynamic programming). Through illustrative experimentation using the Wilcoxon signed rank test, we proved that context-based route planning is much more effective than distance-based route planning., In addition, we found that the optimal solution (shortest paths) through the distance-based route planning might not be optimized in real situation because road condition is very dynamic and unpredictable while affecting most vehicles' moving costs. For further study, while more information is needed for a more accurate estimation of moving vehicles' costs, this study still stands viable in the applications to reduce moving costs by effective route planning. For instance, it could be applied to deliverers' decision making to enhance their decision satisfaction when they meet unpredictable dynamic situations in moving vehicles on the road. Overall, we conclude that taking into account the contexts as a part of costs is a meaningful and sensible approach to in resolving the optimal route problem.

Development of Evolutionary Algorithms for Determining the k most Vital Arcs in Shortest Path Problem (최단경로문제에서 k-치명호를 결정하는 진화 알고리듬의 개발)

  • 정호연;김여근
    • Journal of the Korean Operations Research and Management Science Society
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    • v.26 no.2
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    • pp.47-58
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    • 2001
  • The purpose of this study is to present methods for determining the k most vital arcs (k-MVAs) in shortest path problem (SPP) using evolutionary algorithms. The problem of finding the k-MVAs in SPP is to find a set of k arcs whose simultaneous removal from the network causes the greatest increase in the shortest distance between two specified nodes. Generally, the problem of determining the k-MVAs in SPP has been known as NP-hard. Therefore, to deal with problems of the real world, heuristic algorithms are needed. In this study we present three kinds of evolutionary algorithms for finding the k-MVAs in SPP, and then to evaluate the performance of proposed algorithms.

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Development of Shortest Path Searching Network Reduction Algorithm (최단경로 탐색영역 축소 알고리즘 개발)

  • Ryu, Yeong-Geun
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.12 no.2
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    • pp.12-21
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    • 2013
  • This study developed searching network reduction algorithm for reduce shortest path searching time. Developed algorithm is searching nodes that have the including possibility of less weights path than temporal path that consists minimum number of nodes and minimum sum of the straight line distances. The node that has the including possibility of shortest path is the node that the sum of straight line distance from start node and straight line distance to target node is less than the value that temporary path's weights divided by minimum weights units. If searching network reconstitutes only these nodes, the time of shortest path searching will be reduced. This developed algorithm has much effectiveness that start node and target node is close in large network.

An Anti-Collision System for Vessels Based on Smartphone (스마트폰 기반의 선박 충돌방지 시스템)

  • Cho, Hong-Rae;Lee, Sung-Jong;Park, Jang-Sik;Kim, Hyun-Tae;Yu, Yun-Sik
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2011.10a
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    • pp.470-471
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    • 2011
  • As the increase in maritime traffic and leisure, the marine accident risk has increased in the domestic coast. In this paper, we propose an anti-collision system between vessels using the shortest distance and the time to reach the distance in maritime. the shortest distance and the time to reach the distance calculated with vector analysis using AIS information, a prototype is implemented for smartphone application.

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Computation of the Shortest distance and Forecasting movement distance for Y/T Multi-Cycle System (Multi-Cycle 작업을 위한 Y/T 최단거리 및 예상 이동거리 계산)

  • Park, Tae-jin;Kim, Han-soo;Kim, Cheeyong
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2009.05a
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    • pp.127-130
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    • 2009
  • In this paper, we introduce a Y/T(Yard Tractor) Multi-Cycle System on the basis of RTLS that improves a low efficient loading and unloading. In the proposed approach, we apply the best suited algorithm looking for seeking of the optimum path and the shortest movement distance. In this paper, Our experiment results show that rate of a driving distance is reduced more than 12% compared to the average value, and that is reduced more than 23% compared to the maximum value.

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A Polynomial-time Algorithm for Choosing the Shortest Transportation Path of Logistic Material (최적 보급수송로 선정을 위한 다항시간 알고리듬)

  • 서성철;정규련
    • Journal of the military operations research society of Korea
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    • v.23 no.2
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    • pp.103-119
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    • 1997
  • This paper considers the shortest path problem combined with Min-Min-Sum objective for solving the problem of the military logistics. This paper develops a polynomial-time algorithm for the optimal solution. To analyze the real combat situation, the ability time and distance time of communication line are considered. The complexities of algorithm between previous study and the algorithm developed in this paper is presented. Finally we provide a simple example of application with randomly generated problem.

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A Point-to-Point Shortest Path Search Algorithm in an Undirected Graph Using Minimum Spanning Tree (최소신장트리를 이용한 무방향 그래프의 점대점 최단경로 탐색 알고리즘)

  • Lee, Sang-Un
    • Journal of the Korea Society of Computer and Information
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    • v.19 no.7
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    • pp.103-111
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    • 2014
  • This paper proposes a modified algorithm that improves on Dijkstra's algorithm by applying it to purely two-way traffic paths, given that a road where bi-directional traffic is made possible shall be considered as an undirected graph. Dijkstra's algorithm is the most generally utilized form of shortest-path search mechanism in GPS navigation system. However, it requires a large amount of memory for execution for it selects the shortest path by calculating distance between the starting node and every other node in a given directed graph. Dijkstra's algorithm, therefore, may occasionally fail to provide real-time information on the shortest path. To rectify the aforementioned shortcomings of Dijkstra's algorithm, the proposed algorithm creates conditions favorable to the undirected graph. It firstly selects the shortest path from all path vertices except for the starting and destination vertices. It later chooses all vertex-outgoing edges that coincide with the shortest path setting edges so as to simultaneously explore various vertices. When tested on 9 different undirected graphs, the proposed algorithm has not only successfully found the shortest path in all, but did so by reducing the time by 60% and requiring less memory.

Finding the shortest distance between all pairs of nodes in circular sparse networks by decomposition algorithm (Circular sparse network에서 분할법을 이용한 최단거리 결정)

  • Jun-Hong Kim;Young-Bae Chung
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.26 no.1
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    • pp.47-53
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    • 2003
  • 이 논문은 환(環)을 형성하는 부분네트웍들로 이루어진 sparse network의 특수한 형태에서 최단거리 결정을 위한 효율적인 앨고리즘을 제안한다. 제시된 앨고리즘은 소위 비환(非換) 형태의 sparse network에 대한 최단거리 결정 앨고리즘의 확장이라 할 수 있다. 도우넛 형태를 갖는 sparse network에 대해 최단거리 결정을 위한 접근법으로 하나는 정점제거 방법이고, 다른 하나는 선분제거 방법이다. 여기서 제안된 앨고리즘은 일반적인 n-degree circular sparse network으로 확대될 수 있다.