• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.1
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• pp.177-182
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• 2014

In this paper, we propose an energy efficient sink node based MAC protocol for Wireless Sensor Networks (WSNs). The proposed sink node-based MAC (SB-MAC) protocol uses a RB(rapid beacon) frame to save sender's energy consumption and to reduce transmission delay. The RB frame is a modified IEEE 802.15.4 beacon frame. The RB frame contains the length of the sender nodes data. Using this information other nodes except sender and receiver nodes can be stay sleep mode long time to reduce energy consumption. Results have shown that the SB-MAC protocol outperformed other protocols like X-MAC and RI-MAC in terms of packet delivery delay and energy consumption. The SB-MAC protocol is especially energy efficient for the networks with one sink node and many senders.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.11
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• pp.2435-2441
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• 2010

A global healthcare system based on M2M technology is proposed to support a good mobility, flexibility and scalability to the patients in 6LoWPAN. Sensor nodes integrated with wearable sensors are linked to gateway with IEEE 802.15.4 protocol and 6LoWPAN protocol for data acquisition and transmission purpose via external network. In the server, heart rate variability signals are obtained by signal processing and used for time and frequency domain performance analysis to evaluate the patient's health status. Our approach for global healthcare system with non-invasive and continuous IP-based communication is managed to process large amount of biomedical signals in the large scale of service range accurately.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.364-367
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• 2007

We combined CC2431(Chipcon, Norway), as the platform for the Indoor Location Tracking, which follows Zigbee/IEEE802.15.4 standards in RSSI (Received Signal Strength Indicator) and Base Station Node and then, embodied Indoor Location Tracking System. CC2431 is composed of the Reference Node that transfer its current position at the designated place and the Blind Node. The Blind node receives the current position(X and Y coordinates) of the Reference Node fields which are being contiguous and also, calculates its current position and transfers it to the Base Station Node. The base station node is used for receiving the current position of blind node and passing its data to the PC as a gateway. We can make sure where is the Blind Node not only from the out-of-the-way place of the server side but from the outside in a real-time.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.5
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• pp.1-11
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• 2008

Wireless Sensor Networks is applied to improvement of life convenience or service like U-City as well as environment pollution, tunnel and structural health monitoring, storm, and earthquake diagnostic system. To increase the usability of sensor data and applicability, mobile devices and their facilities allow the applications of sensor networks to give mobile users and actuators the results of event detection at anytime and anywhere. In this paper, we present MUSNEMO(Multi-sensor centric Ubiquitous Smart sensor NEtwork using Mobile devices) developed system for providing more efficient and valuable information services with a variety of mobile devices and network camera integrated to WSN. Our system is performed based on IEEE 802.15.4 protocol stack. To validate system usability, we built sensor network environments where were equipped with five application sensors such magnetic, photodiode, microphone, motion and vibration. We also built and tested proposed MUSNEMO to provide a novel model for event detection systems with mobile framework.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.2
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• pp.106-113
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• 2009

Recently, due to many industrial accidents at construction sites, a variety of researches for structural health monitoring (SHM) of buildings are progressing. For real site application of SHM, one of the advanced technologies has blown as wireless sensor networks (WSN). In this paper, we proposed WIVA(WSN Monitoring framework based on 3D Visualization and Augmented Reality in Mobile Devices) system that applies 3D visualization and AR technology to mobile devices with camera based on WSN in order to expand the extent of information can observe. Moreover, we performed experiments to validate effectiveness in 3D and AR mode that utilize WSN data based on IEEE 802.15.4. In real implementation scenario, we demonstrated a fire occurrence test in 3-story building miniature.

• Journal of the Korea Society of Computer and Information
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• v.14 no.10
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• pp.101-110
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• 2009

The 6LoWPAN(IPv6 Low-power Wireless Personal Area Network) performs IPv6 header compression, TCP/UDP/IGMP header compression, packet fragmentation and re-assemble to transmit IPv6 packet over IEEE 802,15.4 MAC/PHY. However, from the point of view of security. It has the existing security threats issued by IP packet fragmenting and reassembling, and new security threats issued by 6LoWPAN packet fragmenting and reassembling would be introduced additionally. If fragmented packets are retransmitted by replay attacks frequently, sensor nodes will be confronted with the communication disruption. This paper analysis security threats introduced by 6LoWPAN fragmenting and reassembling, and proposes a re-transmission mechanism that could minimize re-transmission to be issued by replay attacks. Re-transmission procedure and fragmented packet structure based on the 6LoWPAN standard(RFC4944) are designed. We estimate also re-transmission delay of the proposed mechanism. The mechanism utilizes timestamp, nonce, and checksum to protect replay attacks. It could minimize reassemble buffer overflow, waste of computing resource, node rebooting etc., by removing packet fragmentation and reassemble unnecessary.

• Proceedings of the Korea Information Processing Society Conference
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• 2007.05a
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• pp.818-821
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• 2007

무선 센서 네트워크에서 특정 지역에 분포된 센서들은 데이터를 감지하고, 싱크 노드는 소스 노드들에게서 데이터를 수집한다. 현재, 여러 연구기관 및 기업에서 무선 센서 네트워크를 구현하고 실용화하기 위해 연구하는 중이며, 대표적인 예로 IEEE Standards의 IEEE 802.15.4와 이를 하위 계층으로 사용하는 ZigBee Alliance 의 ZigBee 가 있다. 본 논문에서는, ZigBee 기반의 네트워크에서 감지된 데이터들을 수집하기 위한 이동성을 지원하는 게이트웨이의 정보처리 메커니즘을 설계한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.10B
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• pp.639-647
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• 2005

When a DEV associates with an existing WPAN, the PNC checks the capabilities of the new DEV to see if it is more capable to be the PNC of the piconet based on the criteria defined in the IEEE Std 802.15. If the new DEV is more capable and the current security policies allow it, then the PNC has the option of handing over control of the piconet to the DEV that has just joined. And, If the PNC is shutting down or wants to leave the WPAN, it also uses the handover process to give control to another DEV in the piconet. However, IEEE 802.15.3 checks only DEV capability information for more PNC capable. For PNC selection, it should consider the radio coverage of new PNC capable DEVs. So, we propose the method of PNC selection with accessibility check. This method manages PNC candidate list in the current piconet. In this paper, we analyze accessibility problems for PNC selection in section 2. In section 3, we explain CI(Configuration Inquiry) process which is proposed by Sony Corporation and propose PCI(PNC Candidate Inquiry) process. Also, we perform numerical analysis to compare PCI process with CI process in section 4. Finally, we conclude in section 5.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.10
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• pp.20-28
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• 2007

Zigbee sensor network base on IEEE802.15.4 has local address of 2 byte on transmit packet data which is pick up the address for each sensor node. Sensor network is requested low power, low cost, many nodes at hues physical area. There for Zigbee is very good solution supporting for next Ubiquitous generation but the Zigbee sensor network has address allocation problem of each sensor node. Is established standard from Zigbee Alliance, to the address allocation method uses Cskip algorithm. The Cskip algorithm use the hazard which allocates an address must blow Hop of the maximum modification and child node number. There is to address allocation and from theoretically it will be able to compose a personal 65536 sensor nodes only actual with concept or space, only 500 degree will be able to compose expansion or the low Zigbee network. We proposed an address allocation method using coordinate value for Zigbee sensor network.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.10
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• pp.2465-2472
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• 2015

Wireless Medium Access Control (MAC) and routing technologies are the basic building blocks making it possible the Internet of Things (IoT). These technologies have been the focus of substantial research in the last decade. Nevertheless, as new networking standards for IoT are being proposed and different solutions are patched together, evaluating the performance of the network becomes unclear. In this paper, a new overview of MAC and routing protocols for IoT and new interactions are given. The IEEE 802.15.4 MAC and Routing Protocol for Low-power Lossy Network (RPL) routing protocols are taken as reference to exemplify and illustrate the discussion. Experimental results show that contention-based access MACs may hurt the routing, unless these two are carefully designed together.