• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.12
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• pp.3081-3099
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• 2012

We propose a new multipath-based reliable routing protocol on MANETs, Multipath-based Reliable routing protocol with Fast-Recovery of failures (MRFR). For reliable message transmission, MRFR tries to find the most reliable path between a source and a destination considering the end-to-end packet reception reliability of the routes. The established path consists of a primary path that is used to transmit messages, and the secondary paths that are used to recover the path when detecting failures on the primary path. After establishing the path, the source transmits messages through the primary path. If a node detects a link failure during message transmission, it can recover the path locally by switching from the primary to the secondary path. By allowing the intermediate nodes to locally recover the route failure, the proposed protocol can handle the dynamic topological change of the MANETs efficiently. The simulation result using the QualNet simulator shows that the MRFR protocol performs better than other protocols in terms of the end-to-end message delivery ratio and fault-tolerance capability.

• Proceedings of the Korean Statistical Society Conference
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• 2002.11a
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• pp.129-132
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• 2002

네트워크를 설계하거나 평가하는데 있어 중요한 문제 중 하나는 그 네트워크를 구성하는 요소들간의 상대적 중요도(importance)에 관한 문제이다. 이런 중요도를 나타내는 여러 가지 측도들 중 하나인 Joint Reliability Importance(JRI)는 Hong & Lie(1993)에 의해 소개되었으며, 네 가지 파생된 서브그래프의 신뢰성을 구하여 JRI를 계산하는 방법이 제시되었다. 본 연구에서는 minimal path set을 이용하여 파생되는 서브 그래프 신뢰성 계산에서의 중복되는 계산과정을 줄임으로써 JRI를 보다 효율적으로 구하는 방법을 제시하고자 한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.12A
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• pp.1917-1921
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• 1999

In this paper, we studied the method of path distribution in order to increase reliability of the network by reducing path congestion, solving the problems of increasing blocking statistics, and increasing the utilization of network resource. A scheme of efficient path calculation which can reduce the traffic congestion in an arbitrary link is proposed by path calculation equations considering link occupation rates. A rapid method of establishing a connection which can efficiently cope with accidental connection failure are studied.

• IEMEK Journal of Embedded Systems and Applications
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• v.18 no.6
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• pp.327-333
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• 2023

Existing studies on the UAV (Unmanned Aerial Vehicle)-based CPS (Cyber Physical System) environment lack forest fire monitoring and forest fire reconnaissance using real-world UAVs. So, it is necessary to monitor forest fires early through CPS based on real-world UAVs with high reliability and resource management efficiency. In this paper presents an MFG (Misstion File Generater) that automatically generates a flight path of an UAV for forest fire monitoring in a CPS environment. MFG generates flight paths based on a hiking trail with a high fire probability due to a true story of an entrant. We have confirmed that the flight path generated by MFG can be applied to the UAV. Also, we have verified that the UAV flies according to the flight path generated by MFG in simulation, with a negligible error rate.

• Journal of Applied Reliability
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• v.6 no.2
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• pp.187-194
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• 2006

In this paper, We presented the algorithm for estimating a reliability between nodes in wireless communication network such as RBN and MANET To estimate the reliability between nodes, we first modeled RNB and MANET as probability graph. Branches of the graph are always reliable and the probability of node failure is independent. After all possible simple path which can be established between two nodes are examined, we perform sharp arithmetic to remove repetition event between two nodes. Using probability for each variable of the minimized Boolean equation, we present the reliability formula.

• Journal of Applied Reliability
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• v.6 no.4
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• pp.297-306
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• 2006

In this paper, We presented the algorithm for estimating a reliability between nodes in wireless distributed sensor networks (DSN). To estimate the reliability between nodes, we first modeled DSN as probability graph. Links of the graph are always reliable and the probability of node failure is independent. After all possible simple path which can be established between two nodes are examined, we perform sharp operation to remove repetition event between two nodes. Using probability for each variable of the minimized Boolean equation, we present the reliability formula.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.1085-1092
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• 2022

Travel distance is a parameter mainly used in the objective function of Construction Site Layout Planning (CSLP) automation models. To obtain travel distance, common approaches, such as linear distance, shortest-distance algorithm, visibility graph, and access road path, concentrate only on identifying the shortest path. However, humans do not necessarily follow one shortest path but can choose a safer and more comfortable path according to their situation within a reasonable range. Thus, paths generated by these approaches may be different from the actual paths of the workers, which may cause a decrease in the reliability of the optimized construction site layout. To solve this problem, this paper adopts reinforcement learning (RL) inspired by various concepts of cognitive science and behavioral psychology to generate a realistic path that mimics the decision-making and behavioral processes of wayfinding of workers on the construction site. To do so, in this paper, the collection of human wayfinding tendencies and the characteristics of the walking environment of construction sites are investigated and the importance of taking these into account in simulating the actual path of workers is emphasized. Furthermore, a simulation developed by mapping the identified tendencies to the reward design shows that the RL agent behaves like a real construction worker. Based on the research findings, some opportunities and challenges were proposed. This study contributes to simulating the potential path of workers based on deep RL, which can be utilized to calculate the travel distance of CSLP automation models, contributing to providing more reliable solutions.

• The Journal of Korea Robotics Society
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• v.19 no.1
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• pp.23-30
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• 2024

This paper studies a GPS error filtering method that takes into account the continuity of the ongoing path to enhance the safety of autonomous agricultural mobile robots. Real-Time Kinematic Global Positioning System (RTK-GPS) is increasingly utilized for robot position evaluation in outdoor environments due to its significantly higher reliability compared to conventional GPS systems. However, in orchard environments, the robot's current position obtained from RTK-GPS information can become unstable due to unknown disturbances like orchard canopies. This problem can potentially lead to navigation errors and path deviations during the robot's movement. These issues can be resolved by filtering out GPS information that deviates from the continuity of the waypoints traversed, based on the robot's assessment of its current path. The contributions of this paper is as follows. 1) The method based on the previous waypoints of the traveled path to determine the current position and trajectory. 2) GPS filtering method based on deviations from the determined path. 3) Finally, verification of the navigation errors between the method applying the error filter and the method not applying the error filter.

• Journal of the Korea Society of Computer and Information
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• v.16 no.1
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• pp.89-99
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• 2011

In this paper, we propose an routing algorithm for ultra low power and high reliable transmission in WBAN environment. This algorithm is to minimize energy consumption and to maximize the life and reliability for medical devices. Also, this algorithm is not only medical devices but also non-medical devices is to minimize energy consumption and to maximize the life of device. The combination of the distance from the previous node and residual energy calculates weight. The calculated weight is used to calculate the weight of full path by cumulative weights. The full path to the smallest of the weights are set to the path. Also this algorithm is able to select another path to avoid the error path by determining the link status between nodes, when occurs link error and congestion. In this paper, we show that WSN routing algorithm based on shortest hop count routing algorithm and EAR routing algorithm compared to ensure high reliability and low power characteristic of WBAN to be verified through simulations.

• Journal of the Korean Society of Safety
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• v.11 no.1
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• pp.27-38
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• 1996

The aim of this paper is to develop more fast algorithm for evaluation of the reliability of networks and system. It is illustrated with examples. This paper derived the algorithm to calculate the acyclic directed graph G(deals with the problem of the s-t graph). The language PASCAL was used to implement the algorithm. Three Examples are calculated and the calculation time is shorter than the time by program in $\ulcorner$21$\lrcorner.