• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권9호
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• pp.3120-3137
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• 2021

Small-sized IoT wireless sensing devices can be deployed with small aircraft such as drones, and the deployment of mobile IoT devices can be relocated to suit data collection with efficient relocation algorithms. However, the terrain may not be able to predict its shape. Mobile IoT devices suitable for these terrains are hopping devices that can move with jumps. So far, most hopping sensor relocation studies have made the unrealistic assumption that all hopping devices know the overall state of the entire network and each device's current state. Recent work has proposed the most realistic distributed network environment-based relocation algorithms that do not require sharing all information simultaneously. However, since the shortest path-based algorithm performs communication and movement requests with terminals, it is not suitable for an area where the distribution of obstacles is uneven. The proposed scheme applies a simple Monte Carlo method based on relay nodes selection random variables that reflect the obstacle distribution's characteristics to choose the best relay node as reinforcement learning, not specific relay nodes. Using the relay node selection random variable could significantly reduce the generation of additional messages that occur to select the shortest path. This paper's additional contribution is that the world's first distributed environment-based relocation protocol is proposed reflecting real-world physical devices' characteristics through the OMNeT++ simulator. We also reconstruct the three days-long disaster environment, and performance evaluation has been performed by applying the proposed protocol to the simulated real-world environment.

• 한국인터넷방송통신학회논문지
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• 제17권2호
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• pp.205-210
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• 2017

무선 센서 네트워크는 환경 모니터링, 감시 시스템, 무인 우주 탐사 등의 다양한 분야에서 활용 가능하다. 하지만 노드의 부적절한 배치로 인해 센싱할 수 없는 지역이 생기거나 특정 지역에 노드가 과도하게 중복 될 수도 있다. 이는 데이터 수집을 어렵게 하고, 에너지 낭비를 야기할 수 있다. 본 논문에서는 노드 재배치를 통해 이러한 배치 문제를 해결한다. 먼저 중복 배치된 노드를 찾고, 이 노드들을 센싱할 수 없는 지역으로 옮겨서 최대한 넓은 지역을 센싱할 수 있도록 한다. 본 논문에서는 이를 위해 필요한 효율적인 알고리즘을 제안하고 시뮬레이션을 통해 제안 방법을 검증하였다.

• 디지털산업정보학회논문지
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• 제16권4호
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• pp.9-17
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• 2020

When IoT sensor nodes are deployed in areas where data collection is challenging, sensors must be relocated if sensing holes occur due to improper placement of sensors or energy depletion, and data collection is impossible. The sensing hole's cluster header transmits a request message for sensor relocation to an adjacent cluster header through a specific relay node. However, since a specific relay node is frequently used, a member sensor located in a specific cluster area adjacent to the sensing hole can continuously receive the movement message. In this paper, we propose a method that avoids the situation in which the sensing hole cluster header monopolizes a specific relay node and allows the cluster header to use multiple relay nodes fairly. Unlike the existing method in which the relay node immediately responds to the request of the header, the method proposed in this paper solves a ping-pong problem and a problem that the request message is concentrated on a specific relay node by applying a method of responding to the request of the header using a timer. OMNeT++ simulator was used to analyze the performance of the proposed method.