• The Journal of Korean Institute of Communications and Information Sciences
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• v.37B no.9
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• pp.767-777
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• 2012

Topology control increases channel efficiency by controlling transmission power of a node, and as a result, network lifetime and throughput are increased. However, reducing transmission range causes a network connectivity problem, especially in mobile networks. When a network loses connectivity, the network topology should be re-configured. However, topology re-configuration consumes lots of energy because every node need to collect neighbor information. As a result, network lifetime may decrease, even though topology control is being used to prolong the network lifetime. Therefore, network connectivity time needs to be increased to expend network lifetime in mobile networks. In this paper, we propose an Adaptive-Redundant Transmission Range (A-RTR) algorithm to address this need. A-RTR uses a redundant transmission range considering a node status and flexibly changes a node's transmission range after a topology control is performed.

• Journal of the Korean Institute of Intelligent Systems
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• v.21 no.1
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• pp.49-54
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• 2011

In this paper, we represent a mobile robot which can recognize chemical odor, measure concentration, and track its source indoors. The mobile robot has the function of smell that can sort several gases in experiment such as ammonia, ethanol, and their mixture with neural network algorithm and measure each gas concentration with fuzzy rules. In addition, it can not only navigate to the desired position with vision system by avoiding obstacles but also transmit odor information and warning messages earned from its own operations to other nodes by multi-hop communication in wireless sensor network. We suggest the way of odor sorting, concentration measurement, and source tracking for a mobile robot in wireless sensor network using a hybrid algorithm with vision system and gas sensors. The experimental studies prove that the efficiency of the proposed algorithm for odor recognition, concentration measurement, and source tracking.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.10
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• pp.2473-2492
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• 2012

Energy conservation is a vital issue in wireless sensor networks. Recently, employing mobile sinks for data gathering become a pervasive trend to deal with this problem. The sink can follow stochastic or pre-defined paths; however the controlled mobility pattern nowadays is taken more into consideration. In this method, the sink moves across the network autonomously and changes its position based on the energy factors. Although the sink mobility would reduce nodes' energy consumption and enhance the network lifetime, the overhead caused by topological changes could waste unnecessary power through the sensor field. In this paper, we proposed EEDARS, an energy-efficient dual-sink algorithm with role switching mechanism which utilizes both static and mobile sinks. The static sink is engaged to avoid any periodic flooding for sink localization, while the mobile sink adaptively moves towards the event region for data collection. Furthermore, a role switching mechanism is applied to the protocol in order to send the nearest sink to the recent event area, hence shorten the path. This algorithm could be employed in event-driven and multi-hop scenarios. Analytical model and extensive simulation results for EEDARS demonstrate a significant improvement on the network metrics especially the lifetime, the load and the end-to-end delay.

• The KIPS Transactions:PartC
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• v.16C no.1
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• pp.91-100
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• 2009

Given the increased interest in ubiquitous computing, wireless sensor network has been researched widely. The localization service which provides the location information of mobile user, is one of important service provided by sensor network. Many methods to obtain the location information of mobile user have been proposed. However, these methods were developed for only one mobile user so that it is hard to extend for multiple mobile users. If multiple mobile users start the localization process concurrently, there could be interference of beacon or ultrasound that each mobile user transmits. In the paper, we propose IAL, the localization technique with interference avoidance for multiple mobile nodes in mobile wireless sensor networks. In IAL, interference is prevented by forcing the mobile node to get the permission of localization from anchor nodes. For this, we define LIP packet type for localization initiation by mobile node and LGP packet type for localization grant by anchor node. LRP packet type is used to reject localization by anchor node for interference avoidance. The experimental result shows that the number of interference between nodes are increased in proportion to the number of mobile nodes and IAL provides efficient localization.

• International journal of advanced smart convergence
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• v.1 no.2
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• pp.1-11
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• 2012

IP-based Wireless Sensor Networks (IP-WSNs) are gaining importance for their broad range of applications in health care, home automation, environmental monitoring, industrial control, vehicle telematics, and agricultural monitoring. In all these applications, a fundamental issue is the mobility in the sensor network, particularly with regards to energy efficiency. Because of the energy inefficiency of network-based mobility management protocols, they can be supported via IP-WSNs. In this paper, we propose a network-based mobility-supported IP-WSN protocol called mSFP, or the mSFP: "Multicasting-supported Inter-Domain Mobility Management Scheme in Sensor-based Fast Proxy Mobile IPv6 Networks". Based on [8,20], we present its network architecture and evaluate its performance by considering the signaling and mobility cost. Our analysis shows that the proposed scheme reduces the signaling cost, total cost, and mobility cost. With respect to the number of IP-WSN nodes, the proposed scheme reduces the signaling cost by 7% and the total cost by 3%. With respect to the number of hops, the proposed scheme reduces the signaling cost by 6.9%, the total cost by 2.5%, and the mobility cost by 1.5%. With respect to the number of IP-WSN nodes, the proposed scheme reduces the mobility cost by 1.6%.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.3
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• pp.119-124
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• 2014

In this paper, we propose the active rule system applying with emotional margin for power saving control. The proposed system in this paper is a part of the system which derives smart power saving by adjusting the illuminance using active rules within compromising the user's emotion. For this, we set the specific range of standard illuminance and the lower bound of user's emotional margin of illuminance based on measurements and analysis, and use these data in design of active rules. And then, we design and implement the active rule system using mobile agent. The mobile agent in the proposed system migrates to the destination sensor nodes, acquires and transmits sensor data according to the purpose and needs through the active rules, and directly executes the actions corresponding to the optional events(changed sensor data and/or time etc.). And then, we show the potential applicability of the proposed active rule system in various active sensor network applications through the interaction with the rule base and mobile sensor network middleware system.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.5
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• pp.203-210
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• 2011

The current sensor network analyzes the data collected by the sensing of fixed sensor nodes and provides a service. However, this method cannot actively handle the state and the change in the position of people, 'the target for sensing and the change in the environment', including home automation, building automation and real-time road & weather information, and healthcare environment, etc. To support a dynamic situation which is appropriate for an individual in this diverse environment, it is necessary to provide actively differentiated specific information according to the movement of people and the changes in the environment. In this study, a individualized sensor mobile agent middleware which provides the individualized information (the location of fire incidence and the trace for the path of spread), has been realized through the sensor network environment constructed by the installation of wireless sensor nodes mounted with mobile agent middlewares in buildings.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.5B
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• pp.833-839
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• 2010

Mobility of sensor node is one of the rising issues in Wireless Sensor Networks (WSN). However, current security researches on WSN only consider static environments. Thus they are not sufficient to be deployed in the dynamic environment where the resource is limited. In this paper, we propose the efficient node authentication and key exchange protocol that reduces the overhead in node re-authentication.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10d
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• pp.431-434
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• 2006

센서 네트워크(Sensor Network)는 항공기(Aircraft)로 살포되는 센서 노드(Sensor Node)들로 구성된다. 자연적인 장애물 즉, 바람, 나무 등이나 빌딩과 같은 조형물로 인해 적절한 위치에 센서 노드들이 배치되지 못하여 불필요한 에너지 소비와 전송 지연 등이 발생하게 된다. 본 논문에서는 기존 논문에서 사용하던 고정 노드(Static Node) 뿐만 아니라 이동 노드(Mobile Node)를 센서 필드(Sensor Field)에 배치 할 것이다. 각 센서 노드의 정보를 싱크(Sink)노드가 수집 분석 후 본 논문에서 제시한 제안에 따라 이동 노드 위치 변경하여 센서 네트워크 라우팅(Routing)의 성능을 향상시키는 방법을 제안한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.1077-1080
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• 2009

Dense meteorological data are hard to be collected on the limited urban areas because of vest cost which is required to install the corresponding sensors on the areas. Recently, to overcome this problem, the sensor network technique comes to the fore. This paper studies an application to service the meteorological map using mobile phone sensors. A design results for system implementation are introduced in this paper.