• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.3B
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• pp.453-461
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• 2010

A critical issue in wireless sensor networks is an energy-efficiency since the sensor batteries have limited energy power and, in most cases, are not rechargeable. The most practical manner relate to this issue is to use a node wake-up scheduling protocol that some sensor nodes stay active to provide sensing service, while the others are inactive for conserving their energy. Especially, CTC (Connected Target Coverage) problem has been considered as a representative energy-efficiency problem considering connectivity as well as target coverage. In this paper, we propose a new energy consumption model considering multiple-targets and create a new problem, CMTC (Connected Multiple-Target Coverage) problem, of which objective is to maximize the network lifetime based on the energy consumption model. Also, we present SPT (Shortest Path based on Targets)-Greedy algorithm to solve the problem. Our simulation results show that SPT-Greedy algorithm performs much better than previous algorithm in terms of the network lifetime.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.29 no.4
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• pp.75-82
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• 2006

The main objective of this study is to find out the shortest path of the vehicle routing problem with time window constraints by using both genetic algorithm and heuristic. Hard time constraints were considered to the vehicle routing problem in this suggested algorithm. Four different heuristic rules, modification process for initial and infeasible solution, 2-opt process, and lag exchange process, were applied to the genetic algorithm in order to both minimize the total distance and improve the loading rate at the same time. This genetic algorithm is compared with the results of existing problems suggested by Solomon. We found better solutions concerning vehicle loading rate and number of vehicles in R-type Solomon's examples R103 and R106.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2003.09a
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• pp.252-255
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• 2003

In this paper, we suggest the method for a service robot to move safely from an initial position to n goal position in the wide environment like a building. There is a problem using odometry encoder sensor to estimate the position of n mobile robot in the wide environment like a building. Because of the phenomenon of wheel's slipping, a encoder sensor has the accumulated error of n sensor measurement as time. Therefore the error must be compensated with using other sensor. A vision sensor is used to compensate the position of a mobile robot as using the regularly attached light's panel on a building's ceiling. The method to create global path planning for a mobile robot model a building's map as a graph data type. Consequently, we can apply floyd's shortest path algorithm to find the path planning. The effectiveness of the method is verified through simulations and experiments.

• Annual Conference of KIPS
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• 2001.04b
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• pp.1165-1168
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• 2001

최단경로문제(Shortest Path Problem)는 네트???p에서 하나 혹은 그 이상의 노드들의 쌍 사이에서 가장 짧은 경로, 가장 저렴한 경로 또는 가장 신뢰할 만한 경로를 찾을 때 고려된다. 컴퓨터나 통신망들은 edge-weighted 그래프로 대치될 수 있으며 그렇게 함으로써 최단 경로를 찾아줄 수 있다. 통신 링크는 실제 실패할 수도 있고, 또한 전송될 데이터의 양에 따라 전달되는 시간이 달라지기도 하므로, 가장 신뢰할만한 경로 중에서 가장 빠른 경로(The Quickest Most Reliable Path) 문제와 가장 빠른 경로 중에서 가장 신뢰할만한 경로(The Most Reliable Quickest Path) 문제는 최단경로문제보다 더 현실적이다[1]. 이 논문에서는 그 중 '가장 신뢰할만한 경로 중에서 가장 빠른 경로' 문제를 자바를 사용하여 시각화함으로써 가변 상황에 따라 다른 경로를 찾아주는 과정을 보여준다.

• Journal of the Korean Society of Industry Convergence
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• v.20 no.2
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• pp.89-95
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• 2017

In this paper, we suggest the method for a mobile robot to move safely from an initial position to a goal position in the wide environment like a building. There is a problem using odometry encoder sensor to estimate the position of a mobile robot in the wide environment like a building. Because of the phenomenon of wheel's slipping, a encoder sensor has the accumulated error of a sensor measurement as time. Therefore the error must be compensated with using other sensor. A vision sensor is used to compensate the position of a mobile robot as using the regularly attached light's panel on a building's ceiling. The method to create global path planning for a mobile robot model a building's map as a graph data type. Consequently, we can apply floyd's shortest path algorithm to find the path planning. The effectiveness of the method is verified through simulations and experiments.

• Journal of The Korean Association of Information Education
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• v.20 no.3
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• pp.243-254
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• 2016

This study has produced a checker of the shortest path search problem with a total of 19 questions as a web-based computer evaluation based on the 'TRAFFIC' questions of PISA 2012. It is because the computer has been settled as an indispensable and significant instrument in the process of solving the problems of everyday life and as a media that is underlying in assessment. Therefore, information gifted students should be able to solve the problem using the computer and give clear enough commands to the computer so that it can perform the procedure. In addition, since it is the age that the computational thinking is affecting every sectors, it should give students new educational stimuli. The relationship between the rate of correct answers and the time took to solve the problem through the shortest route search process showed a significant correlation the variable that affected the problem solving as the difficulty of the question rises due to the increase of nodes and edges turned out to be the node than the edge. It was revealed that information gifted students went through algorithmic thinking in the process of solving the shortest route search problem. And It could be confirmed cognitive characteristics of the information gifted students such as 'ability streamlining' and 'information structure memory'.

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

• Proceedings of the Korea Multimedia Society Conference
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• 2002.05d
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• pp.565-569
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• 2002

본 논문에서는 방향그래프의 특정한 두 정점 사이의 최단 시간 및 최단 경로를 구하는 과정을 EMFG를 이용하여 수학적으로 해석하였다. 특정한 두 정점 사이의 최단 시간 및 최단 경로를 구하기 위해 방향그래프를 EMFG로 변환하는 방법과 접속행렬을 이용한 EMFG의 수학적 해석[10]을 적용한 최단 경로 알고리듬을 제안한다. 제안된 알고리듬을 시스템에 적용하여 알고리듬이 올바르게 동작하는 것을 확인하였으며, 방향그래프를 EMFG로 변환하여 해석하면 최단 시간 및 최단 경로를 파악하는 시스템의 분석 및 설계가 용이하여 시스템의 성능향상에 도움이 될 것으로 기대된다.

• Journal of the Korea Society of Computer and Information
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• v.21 no.4
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• pp.25-30
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• 2016

We consider energy efficient transmit and receive strategy for a delay sensitive data. More specifically, we investigate an energy optimum scheduling characteristics for the 2 user interference channel where each user interferes to each other. First, we determine the optimum transmission rate region each individual user may have for optimum transmission. Next, we consider the optimum transmission region of two users together. Shortest path algorithm can be used for further reduction of search space. Eventually, we can reduce computational complexity. We then examine the performance of the optimum transmission strategy for various system environments.

• Proceedings of the IEEK Conference
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• 2000.11c
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• pp.59-62
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• 2000

In this paper, We propose the new interconnection network which is designed to edge numbering method using inorder traversal a Fibonacci trees and its jump sequence is Fibonacci numbers. It has a simple (shortest path)routing algorithm, diameter, node degree. It has a spaning subtree which is Fibonacci tree and it is embedded Fibonacci tree. It is compared with Hypercube. We improve diameter compared with Hypercube on interconnection network measrtes.