• Proceedings of the Korea Information Processing Society Conference
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• 2014.04a
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• pp.130-132
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• 2014

저 전력 기술에 기반한 무선 센서 네트워크 (Wireless Sensor networks, WSN) 기술은 유비쿼터스 사회의 중요한 핵심 기술 중 하나이다. 본 논문에서는 이러한 WSN에 기반한 응용으로서 국경 감시 및 제어 시스템을 제안한다. 시스템은 센서노드, 게이트웨이, 서버, 모바일 애플리케이션으로 구성된다. 모바일 애플리케이션은 사용자모드와 관리자모드로 나뉘어, 일반 사람들도 스마트폰을 통해 국경침범을 감시하고 주변 환경에 대한 정보를 얻을 수 있다. 관리자모드에서는 센서노드의 유동적 작동을 위해 원격으로 소프트웨어 업데이트를 할 수 있다. 또한 저 전력 센서노드의 확장성을 위해 멀티 홉 라우팅 프로토콜을 적용하여 구현하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2022.05a
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• pp.441-442
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• 2022

교통사고 예측은 차량의 블랙박스 동영상을 통해 사고 발생을 최대한 빨리 예측하는 것을 목표로 한다. 이는 안전한 자율주행 시스템을 보장하는 데 중요한 역할을 한다. 다양한 교통 상황과 카메라의 제한된 시야로 인해 프레임에서 사고 가능성을 조기에 관찰하는 것은 어려운 도전이다. 예측의 핵심 기술은 객체의 시공간 관계를 학습하는 것이다. 본 논문에서는 블랙박스 동영상에서 사고 예측을 위한 계산 모델을 제안한다. 이것을 사용하여 사고 예방을 강화한다. 이 모델은 사고 위험에 대한 운전자의 시각적 인식에서 영감을 받았다. 객체 탐지기는 동영상 프레임에서 다양한 객체를 탐지한다. 탐지한 객체는 노드 생성기와 특징 추출기 동시에 통과한다. 노드 생성기에서 생성한 노드는 GCN 실행기를 사용한다. GCN 실행기는 각 프레임에 대한 객체의 3D 위치 관계를 계산한 후 공간 특징을 취득한다. 동시에 공간 특징과 특징 추출기에서 얻은 객체의 특징은 GRU 실행기로 보내진다. GRU 실행기 안에 시공간 특징을 암기하고 분석하여 교통사고 확률을 예측한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.12A
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• pp.1188-1197
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• 2010

A most important thing in a connected dominating set(CDS)-based routing in a wireless ad-hoc network is to select a minimum number of dominating nodes and then build a backbone network which is made of them. Node failure in a CDS is an event of non-negligible probability. For applications where fault tolerance is critical, a traditional dominating-set based routing may not be a desirable form of clustering. It is necessary to minimize the frequency of reconstruction of a CDS to reduce message overhead due to message flooding. The idea is that by finding alternative nodes within a restricted range and locally reconstructing a CDS to include them, instead of totally reconstructing a new CDS. With the proposed algorithm, the resulting number of dominating nodes after partial reconstruction of CDS is not changed and also its execution time is faster than well-known algorithm of construction of CDS by 20~40%. In the case of high mobility situation, the proposed algorithm gives better results for the performance metrics, packet receive ratio and energy consumption.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.8
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• pp.1505-1510
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• 2008

In large-scale wireless sensor networks, the deployed nodes cannot be replaced or recharged after first deployment. Also, dead nodes maγ lead to the partition of whole networks. While performing data dissemination under a battery power constraint, energy efficiency is a key design factor of routing protocol. As a solution for the efficient data dissemination, in this paper, we propose a protocol namely Hierarchical Data Dissemination (HDD) which provides scalable and efficient data delivery to multiple sources and mobile sinks. HDD uses the facts that sink nodes are central gathering Points and source-centric data forwarding paths are constructed and it is maintained with two-tier communications. The performance of HDD is compared with TTDD about the energy consumption, data delivery time and data success ration. The extensive simulation results show that HDD Routing Protocol outperforms TIDD by more than $1.5{\sim}3times$ on energy consumption.

• ETRI Journal
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• v.11 no.2
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• pp.51-63
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• 1989

본고에서는 융통성있고 경제적인 디지틀 통신망 구성에 필수적으로 소요되는 망노드에서의 디지틀 다중 및 회선 분기/분배 기술에 대하여 살펴보고 미래의 동기식 전송망에서 핵심이 될 광대역 회선 분기/분배 기술을 실현하기 위한 장치의 구성 방안, 동기 방식, 소요 기능 요구사항, 그리고 응용영역에 대해 고찰하였다.

• 정보화사회
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• s.175
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• pp.48-51
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• 2005

초고속인터넷, 무선통신의 보급과 유비쿼터스 환경으로 발전하면서 기반기술인 임베디드 시스템의 중요성이 커지고 있다. 임베디드 SW는 휴대폰, 디지털 TV, 셋톱박스, 홈네트워크는 물론 스마트카드, RFID, 센서노드 등 광범위한 분야에서 활용된다. 향후 임베디드 SW의 개발 경쟁력은 국가 경쟁력의 지표가 될 전망이어서 중요성이 더욱 커질 것으로 보인다.

• The KIPS Transactions:PartC
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• v.13C no.2 s.105
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• pp.195-202
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• 2006

For applying sensor networking technology for our daily life, security service is essential, and pairwise key establishment is the key point for security. In this paper, we propose fairwise key establishment mechanism for secure coumunication in sensor networks. In the mechanism, we cluster the network field before deployment and predistribute key materials to normal sensor nodes and clusterheads. For clusterheads, more key materials are predistributed, and after deployment, sensor nodes which need to establish pairwise keys with other sensor nodes in different clusters make request for related key materials to their own clusterheads. Our proposal reduces the memory requirements for normal sensor nodes by distributing more information to clusterheads, and it raises the security level and resilience against node captures. In addition, it guarantees perfect pairwise key establishments for every pair of neighboring nodes and provides efficient and secure sensor communications.

• Journal of KIISE:Information Networking
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• v.34 no.6
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• pp.423-434
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• 2007

Vehicular ad-hoc network (VANET), a kind of mobile ad-hoc network (MANET), is a key technology for building intelligent transportation system (ITS). VANET is automatically and temporarily established through vehicle-to-vehicle communication without network infrastructure. It has the characteristics that frequent changes of network topology and node density are occurred and messages are disseminated through several relay nodes in the network. Due to frequent change of network topology and node density, however, VANET requires an effective relay node selection scheme to disseminate messages through the multi-hop broadcast. In this paper, we propose a contention window based multi-hop broadcast scheme for VANET. Each node has an optimized contention window and competes with each other for a relay node. The experimental results show that the proposed scheme has a better performance than the distance-based deterministic broadcast scheme in terms of message propagation delay and network traffic.

• KIPS Transactions on Computer and Communication Systems
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• v.4 no.1
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• pp.11-14
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• 2015

WSN (Wireless Sensor Network) based on low-power is one of the core technologies in the ubiquitous society. In this paper, we present a border surveillance and control system in WSN environment. The system consists of static sensor node, mobile sensor node, static gateway, mobile gateway, server and mobile application. Mobile applications are divided into user mode and manager mode. So users monitor border surveillance through mobile phone and get information of border network environment without time and space constraints. In manager mode, for the flexible operation of nodes, manager can update to the software remotely and adjust the position of the mobile node. And also we implement a suitable multi-hop routing protocol for scalable low-power sensor nodes and confirm that the system operates well in WSN environment.

• Journal of IKEEE
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• v.20 no.4
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• pp.449-453
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• 2016

Failures would occur because of the hostile nature environment in Wireless Sensor Networks (WSNs) which is deployed randomly. Therefore, considering faults in WSNs is essential when we design WSN. This paper classified fault model in the sensor node. Especially, this paper proposed new error correcting code scheme and fault recovery algorithm in the CH(Cluster Head) node. For the range of the small size information (<16), the parity size of the proposed code scheme has the same parity length compared with the Hamming code, and it has a benefit to generate code word very simple way. This is very essential to maintain reliability in WSN with increase power efficiency.