• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.11B
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• pp.1363-1372
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• 2011

Flooding based routing protocols are usually used to disseminate information in wireless sensor networks. Those approaches, however, require message retransmissions to all nodes and induce huge collision rate and high energy consumption. In this paper, HoGoP (Hop based Gossiping Protocol) in which all nodes consider the number of hops from sink node to them, and decide own gossiping probabilities, is introduced. A node can decide its gossiping probability according to the required average reception percentage and the number of parent nodes which is counted with the difference between its hop and neighbors' ones. Therefore the decision of gossiping probability for network topology is adaptive and this approach achieves higher message reception percentage with low message retransmission than the flooding scheme. Through simulation, we compare the proposed protocol with some previous ones and evaluate its performance in terms of average reception percentage, average forwarding percentage, and forwarding efficiency. In addition, average reception percentage is analyzed according to the application requirement.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.43 no.4 s.310
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• pp.15-22
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• 2006

Nowadays, there is called energy saving, that it is accomplished with a lot study and application development as according to demand of all around world. It is using to network device of wire or wireless such as internet, lan, plc, and zigbee and that we should be accomplished to study about method that spending a little cost to fatal error in control system that be expected of frequent occurrence on network, and that have method to do construction a little bit tried out. Also, in that such a embedded system with network function case, there is important thing that it is remote management to network node and control methods to trust because firmware upgrade have the advantage of more than the other device. In this paper, we have verified through a result of experiment for efficient remote management and control method as previously stated in this paper, that it is area of the PLC for sensor node and doing management to relay, and implementation of the LACC which is core part of the ESS, and in order to get a result to trust from doing analysis of capacity and test.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.5
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• pp.79-85
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• 2009

A sink node and its neighbor nodes spend more energy than other nodes since a stationary sink node collects data from wireless sensor networks(WSNs). For larger WSNs, the unbalanced energy of nodes causes the operation of WSNs to stop rapidly. This paper proposes a data gathering method by adapting the mobile sink to prolong the life time of large WSNs. After partitioning a network into several clusters, a mobile sink visits each cluster and collects data from it. An efficient algorithm is proposed to improve the energy efficiency by delivering the message from the mobile sink to the cluster head as well as to reduce the data gathering delay, which is the disadvantage of the mobile sink. Also, The algorithm is analyzed for the energy consumption and the data gathering delay. The validity of the ananlysis result is confirmed by the simulation.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11a
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• pp.397-399
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• 2005

무선 센서노드를 활용한 다양한 네트워크 설계 기술은 실생활의 각종 정보 수집에서부터 환경 모니터링까지 폭넓은 활용범위를 바탕으로 저전력 노드 설계 기술, 노드간 라우팅 프로토콜, 초소형 운영체제 및 미들웨어기술 등 관련 연구가 활발히 수행되고 있으며, 실내 센서네트워크에 분포된 노드의 절대위치를 측정하는 위치인식 시스템은 노드의 이동성, 다수성 그리고 환경의 제약성으로 인해 이를 보완할 시스템이 요구되고 있다. 이에 본 논문에서는 고정 센서노드의 배치밀도에 따라 위치정보를 선별적으로 처리하는 위치데이터 처리기와 다중 위치데이터의 발생을 원천적으로 차단하는 노드간 라우팅 기법을 통해, 센서노드의 이동성과 다중성을 효과적으로 보완하는 실내 이동객체 위치인식 시스템을 설계하고 서비스 구현을 위한 센서네트워크 플랫폼을 제안한다.

• Journal of the Korea Society of Computer and Information
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• v.22 no.9
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• pp.91-97
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• 2017

IoT (Internet of Things) systems are based on heterogeneous hardware systems of different types of devices interconnected each other, ranging from miniaturized and low-power wireless sensor node to cloud servers. These IoT systems composed of heterogeneous hardware utilize data sets collected from a particular set of sensors or control designated actuators when needed using open APIs created through abstraction of devices' resources associated to service applications. However, previously existing IoT services have been usually developed based on vertical platforms, whose sharing and exchange of data is limited within each industry domain, for example, healthcare. Such problem is called 'data silo', and considered one of crucial issues to be solved for the success of establishing IoT ecosystems. Also, IoT services may need to dynamically organize their services according to the change of status of connected devices due to their mobility and dynamic network connectivity. We propose a way of dynamically composing IoT services under the concept of WoT (Web of Things) where heterogeneous devices across different industries are fully integrated into the Web. Our approach allows developers to create IoT services or mash them up in an efficient way using Web objects registered into multiple standardized horizontal IoT platforms where their resources are discoverable and accessible. A Web-based service composition tool is developed to evaluate the practical feasibility of our approach under real-world service development.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.2
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• pp.514-537
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• 2020

Wireless sensor network (WSN) is a distributed network composed of many sensory nodes. It is precisely due to the clustering unevenness and cluster head election randomness that the energy consumption of WSN is excessive. Therefore, a many-objective optimization WSN energy balance model is proposed for the first time in the clustering stage of LEACH protocol. The four objective is considered that the cluster distance, the sink node distance, the overall energy consumption of the network and the network energy consumption balance to select the cluster head, which to better balance the energy consumption of the WSN network and extend the network lifetime. A many-objective optimization algorithm to optimize the model (LEACH-ABF) is designed, which combines adaptive balanced function strategy with penalty-based boundary selection intersection strategy to optimize the clustering method of LEACH. The experimental results show that LEACH-ABF can balance network energy consumption effectively and extend the network lifetime when compared with other algorithms.

• Korean Journal of Materials Research
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• v.17 no.12
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• pp.660-663
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• 2007

Piezoelectric energy harvesting from our surrounding vibration has been studied for driving the wireless sensor node. To change the vibration energy into the electric-energy efficiently, the natural frequency of cantilever needs to be adjusted to that of a vibration source. When adding 6.80g mass on the end of the fabricated cantilever, a natural frequency shifts from 136 Hz into 49.5 Hz. In addition, electro-mechanical coupling factor increased from 10.20% to 11.90% and resulted in the 1.18 times increase of maximum output power.

• Proceedings of the KAIS Fall Conference
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• 2009.12a
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• pp.953-956
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• 2009

무선 센서 네트워크에서 이동하는 표적의 위치를 추정하기 위한 연구는 센서 노드의 에너지가 제한 되어 있어 센서 노드 상호간의 협력적인 신호처리 기법이 필수적이다. 기존의 무선 센서 네트워크에서 이동 표적의 위치를 추정하는 방법은 각 센서 노드에서 이동 표적으로부터 수신된 신호를 이용해 수신신호강도, 잡음제거, 압축 등의 신호처리를 수행하고 기지국으로 전송하는 형태이다. 이런 기존의 기법은 애드 호크 방법의 무선 센서 네트워크에는 적용이 어렵고, 각 센서 노드에서 신호처리 및 통신에 의한 에너지 소모가 크기 때문에 무선 센서 네트워크의 생존 시간이 짧아지게 된다. 본 논문에서는 웨이블릿 기반의 무선 센서 네트워크의 협력적 신호 처리 방법을 제안한다. 제안된 방법은 웨이블릿 변환을 이용한 센서노드에서의 에너지 효율적 특징추출을 수행하고 각 센서 노드간의 특징 전송을 통해 표적의 위치를 추정한다.

• Proceedings of the KAIS Fall Conference
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• 2011.12b
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• pp.697-700
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• 2011

무선센서네트워크 (WSN, Wireless Sensor Network) 시스템의 활용분야가 다양해짐에 따라 기존 WSN의 문제점을 개선하기 위한 연구가 활발히 이루어지고 있으며, 한정된 배터리 자원 문제는 반드시 해결해야하는 주요한 과제이다. 이러한 문제점을 해결하기 위하여 원격에서 무선 전송 기술을 통하여 에너지를 전송하는 자기유지 지원 기술이 주목받고 있다. 자기유지 지원 기술은 센서 노드의 배터리 교체 및 에너지가 열악한 환경에서 동작 가능한 에너지를 전송하는 기술로서 건물상태 모니터링, 전장 감시 등과 같은 다양한 분야에서 활용되고 있다. 이러한 자기유지 지원 기술은 WSN을 구성하는 센서 노드들 전원 상태를 확인하는 것이 매우 중요하며, 이에 따라 에너지를 공급해야 한다. 따라서 본 논문에서는 자기유지지원을 위한 노드 전원 관리 모니터링 시스템을 설계 한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.703-706
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• 2007

The real-time monitoring about the activity of the human provides useful information about the activity quantity and an ability. This study developed a system for human physical activity assessment in ambulatory monitoring using portable sensing device combining a tri-axial accelerometer and wireless sensor node. This real-time system is able to identify several postures, posture transitions and movements with classification algorithm. In addition, this system also features fall detection capability. The results of the assessment for evaluating the performance of the system show high identification accuracy.