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Guaranteeing Real-Time Services for Industrial Wireless Sensor Networks With IEEE 802.15.4
Seong-eun Yoo,Poh Kit Chong,Daeyoung Kim,Yoonmee Doh,Minh-Long Pham,Eunchang Choi,Jaedoo Huh IEEE 2010 IEEE transactions on industrial electronics Vol.57 No.11
<P>Industrial applications of wireless sensor networks require timeliness in exchanging messages among nodes. Although IEEE 802.15.4 provides a superframe structure for real-time communication, a real-time message-scheduling algorithm is still required to schedule a large number of real-time messages to meet their timing constraints. We propose a distance-constrained real-time offline message-scheduling algorithm which generates the standard specific parameters such as beacon order, superframe order, and guaranteed-time-slot information and allocates each periodic real-time message to superframe slots for a given message set. The proposed scheduling algorithm is evaluated and analyzed extensively through simulations. In addition, a guaranteed time service is implemented in a typical industrial sensor node platform with a well-known IEEE 802.15.4-compliant transceiver CC2420 and ATmega128L to verify the feasibility of the guaranteed time service with the schedule generated by the proposed scheduling algorithm. Through experiments, we prove that the real system runs accurately according to the schedule calculated by the proposed algorithm.</P>
Seong Hoon Kim,Poh Kit Chong,Daeyoung Kim IEEE 2014 IEEE transactions on parallel and distributed syst Vol.25 No.12
<P>In this paper, we propose a novel semi-directional flooding (SDF) algorithm for on-demand routing in IEEE 802.15.4-based low-rate wireless mesh networks (LRWMNs). The novelty of our work is that the proposed routing algorithm enables route discovery request (RREQ) packets to be semi-directionally flooded, with respect to a source-destination pair, in a fully distributed manner without either physical or virtual location information. The idea behind this is to exploit the hierarchical addressing structure that allows each router node to compute logical tree distances between source-destination pairs, which approximately mirrors relative hop distance between the pairs, without message exchanges. By exploiting tree distances with a given target address, the SDF algorithm enables RREQ packets to be flooded over a small area, directed towards the destination. We also apply SDF to a lightweight on-demand routing algorithm like AODVjr, and propose two techniques of adaptive timers and route repair that reduces path setup delays and overheads during route rediscovery, respectively. We carry out extensive simulations and quantitatively show that SDF significantly reduces flooding overhead of network-wide flooding (NWF). We compare SDF-based AODVjr with both NWF-based AODVjr and enhanced hierarchical routing protocol (EHRP) for on demand routing and demonstrate that SDF-based AODVjr drastically reduces route discovery overhead by up to about 95 percent while still providing comparable or better performance than NWF-based AODVjr and EHRP.</P>
One-Hop Neighbor Based Broadcast Scheduling in Wireless Sensor Networks
KIM, Taehong,KIM, Daeyoung,KIT, Chong Poh The Institute of Electronics, Information and Comm 2011 IEICE TRANSACTIONS ON COMMUNICATIONS - Vol.eb94 No.1
<P>For wireless sensor networks in which resources are limited and network topology dynamically changes, we propose the one-hop neighbor based broadcast scheduling (ONBS) algorithm to provide reliable delivery service of broadcast packets. The proposed algorithm reduces the scheduling overhead by allowing each joining node to decide its broadcast schedule based on only its one-hop neighbor information in an on-line and distributed manner. Also, once the broadcast schedule is decided, it is not changed to accommodate a newly joining node in order to prevent the consecutive changes of existing schedules. The network simulation results show that the proposed algorithm provides low latency and high reachability despite low overhead and on-line algorithm design.</P>
'하르방' 프로젝트: USN 임베디드 시스템 기반의 재난재해 방지 서비스
김대영,김재언,유성은,성종우,김도현,김형순,Kim Dae-Yeong,Kim Jae-Eon,Do Thu Thuy,Chong Poh Kit,Yu Seong-Eun,Seong Jong-U,Lopez Tomas Sanchez,Kim Do-Hyeon,Kim Hyeong-Sun 한국통신학회 2006 정보와 통신 Vol.23 No.5
본 논문에서는 USN 임베디드 시스템을 활용한 재난재해 방지 서비스의 설계 및 실증 시험내용을 기술한다. '하르방' 프로젝트로 명명된 본 연구에서는 최근 활발하게 연구되고 있는 USN 기술을 한라산 국립공원의 등산로에 적용함으로써, 고정밀의 기상 정보를 실시간으로 제공하고 재난재해 상황 감시 및 상황 발생을 실시간으로 알려 조기에 상황 대응이 가능하도록 하였다. 현재 독자적으로 연구개발이 이루어지고 있는 BcN, IPv6, USN 기술을 하나로 융합한 차세대 유비쿼터스 네트워크의 구조 연구는 향후 관련산업을 선도함은 물로, 실제 응용에서도 범국가적인 정밀하고 광범위한 기상예보와 재난재해 방지 시스템으로서의 역할을 수행할 것으로 예상된다.