• Title/Summary/Keyword: Shortest Path Algorithm

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An Action Selection Mechanism and Learning Algorithm for Intelligent Robot (지능로봇을 위한 행동선택 및 학습구조)

  • Yoon, Young-Min;Lee, Sang-Hoon;Suh, Il-Hong
    • Proceedings of the KIEE Conference
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    • 2004.11c
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    • pp.496-498
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    • 2004
  • An action-selection-mechanism is proposed to deal with sequential behaviors, where associations between some of stimulus and behaviors will be learned by a shortest-path-finding-based reinforcement team ins technique. To be specific, we define behavioral motivation as a primitive node for action selection, and then sequentially construct a network with behavioral motivations. The vertical path of the network represents a behavioral sequence. Here, such a tree fur our proposed ASM can be newly generated and/or updated. whenever a new sequential behaviors is learned. To show the validity of our proposed ASM, some experimental results on a "pushing-box-into-a-goal task" of a mobile robot will be illustrated.

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Supervisory controller design technique for multiple-AGV systems (다수 무인운반차 시스템을 위한 관리제어기 설계 기법)

  • Lee, J. H.;Choi, M. H.;Lee, B.H.;Kim, J. D.;Park, H.
    • 제어로봇시스템학회:학술대회논문집
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    • 1993.10a
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    • pp.82-87
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    • 1993
  • A supervisory controller design technique for multiple-AGV systems is presented in this paper. The guidepath is represented in the form of a network, and its modifications are easily tested. The network has two-layered structure, where the path sets between each two nodes are made in advance using the K-shortest path algorithm. Occupation times for all links are stored in link-occupation table, and are updated after the dispatching time. Dispatching and scheduling for each AGV are optimized in terms of minimum-time objectives. In all times, the paths are guaranteed to be conflict-free and deadlock-free. The simplicity and flexibility on this control scheme make the supervisory suitable for real applications.

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Performance Analysis of an Adaptive Link Status Update Scheme Based on Link-Usage Statistics for QoS Routing

  • Yang, Mi-Jeong;Kim, Tae-Il;Jung, Hae-Won;Jung, Myoung-Hee;Choi, Seung-Hyuk;Chung, Min-Young;Park, Jae-Hyung
    • ETRI Journal
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    • v.28 no.6
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    • pp.815-818
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    • 2006
  • In the global Internet, a constraint-based routing algorithm performs the function of selecting a routing path while satisfying some given constraints rather than selecting the shortest path based on physical topology. It is necessary for constraint-based routing to disseminate and update link state information. The triggering policy of link state updates significantly affects the volume of update traffic and the quality of services (QoS). In this letter, we propose an adaptive triggering policy based on link-usage statistics in order to reduce the volume of link state update traffic without deterioration of QoS. Also, we evaluate the performance of the proposed policy via simulations.

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A Study on VLSI-Oriented 2-D Systolic Array Processor Design for APP (Algebraic Path Problem) (VLSI 지향적인 APP용 2-D SYSTOLIC ARRAY PROCESSOR 설계에 관한 연구)

  • 이현수;방정희
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.30B no.7
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    • pp.1-13
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    • 1993
  • In this paper, the problems of the conventional special-purpose array processor such as the deficiency of flexibility have been investigated. Then, a new modified methodology has been suggested and applied to obtain the common solution of the three typical App algorithms like SP(Shortest Path), TC(Transitive Closure), and MST(Minimun Spanning Tree) among the various APP algorithms using the similar method to obtain the solution. In the newly proposed APP parallel algorithm, real-time Processing is possible, without the structure enhancement and the functional restriction. In addition, we design 2-demensional bit-parallel low-triangular systolic array processor and the 1-PE in detail. For its evaluation, we consider its computational complexity according to bit-processing method and describe relationship of total chip size and execution time. Therefore, the proposed processor obtains, on which a large data inputs in real-time, 3n-4 execution time which is optimal o(n) time complexity, o(n$^{2}$) space complexity which is the number of total gate and pipeline period rate is one.

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A Via Point Generation Method for Road Navigation of Unmanned Vehicles (무인 차량의 도로주행을 위한 경유점 생성 방법)

  • Choi, Hyuk-Doo;Park, Nam-Hun;Kim, Jong-Hui;Park, Yong-Woon;Kim, Eun-Tai
    • Journal of the Korean Institute of Intelligent Systems
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    • v.22 no.2
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    • pp.161-167
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    • 2012
  • This research deals with generating via points for autonomous navigation on a roadway for unmanned vehicles. When a vehicle plans a path from a starting point to a goal point, it should be able to map out which lane on which road it passes by. For this purpose, we should organize positional information of roads and save it as a database. This paper presents methods to save the database and to plan a shortest path to the goal by generating via points in consideration of the moving direction and the lane directions. Then we prove that the proposed algorithm can find the optimal path on the road through simulations.

A Study of Ant Colony System Design for Multicast Routing (멀티캐스트 라우팅을 위한 Ant Colony System 설계에 대한 연구)

  • Lee, Sung-Geun;Han, Chi-Geun
    • The KIPS Transactions:PartA
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    • v.10A no.4
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    • pp.369-374
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    • 2003
  • Ant Algorithm is used to find the solution of Combinatorial Optimization Problems. Real ants are capable of finding the shortest path from a food source to their nest without using visual informations. This behavior of real ants has inspired ant algorithm. There are various versions of Ant Algorithm. Ant Colony System (ACS) is introduced lately. ACS is applied to the Traveling Salesman Problem (TSP) for verifying the availability of ACS and evaluating the performance of ACS. ACS find a good solution for TSP When ACS is applied to different Combinatorial Optimization Problems, ACS uses the same parameters and strategies that were used for TSP. In this paper, ACS is applied to the Multicast Routing Problem. This Problem is to find the paths from a source to all destination nodes. This definition differs from that of TSP and differs from finding paths which are the shortest paths from source node to each destination nodes. We introduce parameters and strategies of ACS for Multicasting Routing Problem.

Facility Location Problem for Blood Logistics Center (혈액 물류센터 위치 선정 문제)

  • Lee, Sang-Un
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.12 no.2
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    • pp.135-143
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    • 2012
  • This paper suggests the optimal blood distribution center algorithm that satisfies the minimum total transportation cost and within the allowable distribution time $T^*$. Zhang and Yang proposes shifting the location of each point that has less than the average distance of two maximum distance points from each point. But they cannot decide the correct facility location because they miscompute the shortest distance. This algorithm computes the shortest distance $l_{ij}$ from one area to another areas. Then we select the $v_i$ area to thecandidate distribution center location such that $_{max}l_{ij}{\leq}L^*$ and the $v_i$ such that $l_{ij}-L^*$ area that locates in ($v_i,v_k$) and ($v_j,v_l$) from $P_{ij}=v_i,v_k,{\cdots},v_l,v_j$ path and satisfies the $_{max}l_{ij}{\leq}L^*$ condition. Finally, we decide the candidate distribution area that has minimum transportation cost to optimal distribution area.

A Study on Bicycle Route Selection Considering Topographical Characteristics (지형적 특성을 고려한 자전거 경로 선정에 관한 연구)

  • Yang, Jung Lan;Jun, Chul Min
    • Journal of Korean Society for Geospatial Information Science
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    • v.21 no.3
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    • pp.3-9
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    • 2013
  • As interest in green growth picks up, the importance of bicycles which are an environment friendly means of communication has been magnified. However, bicycle routes which are the base of bicycles are designed without considering topographic elements and thus many users are experiencing inconvenience in using bicycles. The present study presents a routing technique to select optimal routes when selecting routes in commuting to school utilizing bicycles. To this end, a formula for optimum route calculation considering slope and intersections was drawn and a method to select optimum routes by applying modified Dijkstra Algorithms was studied. According to the results, the bicycle routes for commuting to school should be selected by the shortest time rather than the shortest distances to the destination, because it required reach the destination faster. Therefore when selecting the routes, it must be based on the shortest time considering waiting time due to crosswalks or crossroads and speed variations due to slopes.

A schedule-based Public Transit Routing Algorithm for Finding K-shortest Paths Considering Transfer Penalties (환승 저항을 고려한 운행시간표 기반 대중교통 다중 경로 탐색 알고리즘)

  • Jeon, Inwoo;Nam, Hyunwoo;Jun, Chulmin
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.17 no.3
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    • pp.72-86
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    • 2018
  • Schedule-based public transit routing algorithm computes a single route that calculated minimum travel time using the departure and arrival times for each stop according to vehicle operation plan. However, additional factors such as transfer resistance and alternative route choice are not reflected in the path finding process. Therefore, this paper proposes a improved RAPTOR that reflected transfer resistance and multi-path searching. Transfer resistance is applied at the time of transfer and different values can be set according to type of transit mode. In this study, we analyzed the algorithm's before and after results compared with actual route of passengers. It is confirmed that the proposed algorithm reflects the various route selection criteria of passengers.

Minimum Cost Path for Private Network Design (개인통신망 설계를 위한 최소 비용 경로)

  • Choe, Hong-Sik;Lee, Ju-Yeong
    • Journal of KIISE:Computer Systems and Theory
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    • v.26 no.11
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    • pp.1373-1381
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    • 1999
  • 이 논문에서는 통신망 설계 응용분야의 문제를 그래프 이론 문제로써 고려해 보았다. 개별 기업체가 서로 떨어진 두 곳을 연결하고자 할 때 공용통신망의 회선을 빌려 통신망을 구축하게 되는데 많은 경우 여러 종류의 회선들이 공급됨으로 어떤 회선을 선택하느냐의 문제가 생긴다. 일반적으로 빠른 회선(low delay)은 느린 회선(high delay)에 비해 비싸다. 그러나 서비스의 질(Quality of Service)이라는 요구사항이 종종 종단지연(end-to-end delay)시간에 의해 결정되므로, 무조건 낮은 가격의 회선만을 사용할 수는 없다. 결국 개별 기업체의 통신망을 위한 통로를 공용 통신망 위에 덮어씌워(overlaying) 구축하는 것의 여부는 두 개의 상반된 인자인 가격과 속도의 조절에 달려 있다. 따라서 일반적인 최소경로 찾기의 변형이라 할 수 있는 다음의 문제가 본 논문의 관심사이다. 두 개의 지점을 연결하는데 종단지연시간의 한계를 만족하면서 최소경비를 갖는 경로에 대한 해결을 위하여, 그래프 채색(coloring) 문제와 최단경로문제를 함께 포함하는 그래프 이론의 문제로 정형화시켜 살펴본다. 배낭문제로의 변환을 통해 이 문제는 {{{{NP-complete임을 증명하였고 {{{{O($\mid$E$\mid$D_0 )시간에 최적값을 주는 의사선형 알고리즘과O($\mid$E$\mid$)시간의 근사 알고리즘을 보였다. 특별한 경우에 대한 {{{{O($\mid$V$\mid$ + $\mid$E$\mid$)시간과 {{{{O($\mid$E$\mid$^2 + $\mid$E$\mid$$\mid$V$\mid$log$\mid$V$\mid$)시간 알고리즘을 보였으며 배낭 문제의 해결책과 유사한 그리디 휴리스틱(greedy heuristic) 알고리즘이 그물 구조(mesh) 그래프 상에서 좋은 결과를 보여주고 있음을 실험을 통해 확인해 보았다.Abstract This paper considers a graph-theoretic problem motivated by a telecommunication network optimization. When a private organization wishes to connect two sites by leasing physical lines from a public telecommunications network, it is often the cases that several categories of lines are available, at different costs. Typically a faster (low delay) lines costs more than a slower (high delay) line. However, low cost lines cannot be used exclusively because the Quality of Service (QoS) requirements often impose a bound on the end-to-end delay. Therefore, overlaying a path on the public network involves two diametrically opposing factors: cost and delay. The following variation of the standard shortest path problem is thus of interest: the shortest route between the two sites that meets a given bound on the end-to-end delay. For this problem we formulate a graph-theoretical problem that has both a shortest path component as well as coloring component. Interestingly, the problem could be formulated as a knapsack problem. We have shown that the general problem is NP-complete. The optimal polynomial-time algorithms for some special cases and one heuristic algorithm for the general problem are described.