• Proceedings of the Korean Information Science Society Conference
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• 2008.06d
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• pp.145-149
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• 2008

센서 네트워크는 수많은 센서 노드로 구성된 센서 필드와 센서 노드로부터 데이터를 수집하는 싱크 노드로 이루어져 있으며, 유비쿼터스에서 중요한 부분을 차지하고 있다. 현재 까지 연구 되어온 센서 네트워크에 대한 연구의 중요한 이슈중 하나는 센서 노드가 제한 자원을 가지기 때문에 한정된 에너지를 최대한으로 사용하여 네트워크의 수명을 연장하는 것이다, 그러나 기존 연구 대부분이 고정된 상태의 싱크 노드를 고려하기 때문에 본 연구에서는 이동성을 가진 싱크노드가 다수가 존재하는 경우 센서 필드에서 수집된 데이터가 이동 싱크 노드까지 끊임없이 전송 될 수 있으며 효율적인 데이터 보급을 제공하는 계층적 라우팅 프로토콜을 제안한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.11a
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• pp.1105-1108
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• 2005

U-Healthcare 서비스는 서비스 이용자가 서비스의 인지없이 이용자의 생체정보와 위치, 주변의 온도와 습도 정보를 수집하고 이를 분석, 가공하여 이용자에게 여러 서비스를 제공하는 것으로 이의 구현을 위해서는 무선 센서 네트워크가 필요하다. 이러한 무선 센서 네트워크에 요구되는 것은 이동성이 있는 모바일 센서 노드의 네트워크 자기 구성과 라우팅에 관한 효율적인 알고리즘이다. 이를 위해 본 논문에서는 실내에 존재하는 여러 이동성이 없는 고정 센서 노드를 기반으로 네트워크 내에 셀을 구성하여, 이 셀을 통해 인접한 이동 모바일 센서 노드의 데이터 전송을 지원하는 계층적 무선 센서네트워크 자기 구성 알고리즘을 제안하였다

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.7 s.349
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• pp.1-13
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• 2006

In this paper, we introduce a novel key management scheme that is based on the key pre-distribution but provides the key re-distribution method, in order to manage keys for message encryption and authentication of lower-layer sensor nodes on hierarchical mobile sensor networks. The characteristics of our key management are as follows: First, the role of key management is distributed to aggregator nodes as well as a sink node, to overcome the weakness of centralized management. Second, a sink node generates keys using regression model, thus it stores only the information for calculating the keys using the key information received from nodes, but does not store the relationship between a node and a key, and the keys themselves. As the disadvantage of existing key pre-distributions, they do not support the key re-distribution after the deployment of nodes, and it is hard to extend the key information in the case that sensor nodes in the network enlarge. Thirdly, our mechanism provides the resilience to node capture(${\lambda}$-security), also provided by the existing key pre-distributions, and fourth offers the key freshness through key re-distribution, key distribution to mobile nodes, and scalability to make up for the weak points in the existing key pre-distributions. Fifth, our mechanism does not fix the relationship between a node and a key, thus supports the anonymity and untraceability of mobile nodes. Lastly, we compare ours with existing mechanisms, and verify our performance through the overhead analysis of communication, computation, and memory.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.1B
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• pp.48-57
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• 2008

Wireless sensor networks are composed of a lot of sensor nodes and they are used to monitor environments. Since many studies on wireless sensor networks have considered a stationary sink node, they cannot provide fully ubiquitous applications based on a mobile sink node. In those applications, routing paths for a mobile sink node should be updated while a sink node moves in order to deliver sensor data without data loss. In this paper, we propose a method to continuously update routing paths for a mobile sink node which can be extended on hierarchical multi-hop routing protocols in wireless sensor networks. The efficiency of the proposed scheme has been validated through comparing existing method using a location based routing protocol by extensive computer simulation.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.1019-1022
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• 2005

본 논문에서는 현재 활발한 연구개발이 이루어지고 있는 유비쿼터스 컴퓨팅, 센서 네트워크 기술을 적용한 무인 감시/추적 시스템을 제시한다. 본 논문의 무인 감시/추적 시스템은 센서네트워크 기술, 다중센서 융합에 의한 탐지 및 위치 인식기술, 무인 감시/추적 알고리즘으로 구성되어 있다. 센서네트워크는 센싱 데이터를 실시간으로 전송하기 위해 노드의 주소를 기반으로 하는 계층적 멀티홉 라우팅 기법을 제안하였다. 침입자와 추적자의 위치 인식은 자기센서 및 초음파센서를 가진 센서모듈들로부터 얻어진 센싱 정보를 융합하고, 이를 확률적으로 침입자 및 추적자의 위치를 결정하는 Particle Filter를 적용한 위치인식 알고리즘을 통해 이루어진다. 추적 알고리즘은 무인 자율 추적을 위해 이동벡터에 기반한 알고리즘이다.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.1
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• pp.22-30
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• 2008

Warehouse has many changes for the stocks by entering and taking. Management about the stocks is important. To manage, sensor network based on RFID is deployed in warehouse. Sensor network uses fluster based on energy and hierarchical routing. Supporting mobility between clusters makes guarantee connectivity for mobile nodes.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37C no.12
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• pp.1328-1336
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• 2012

Compared to terrestrial RF communications, underwater acoustic communications have several limitations such as limited bandwidth, high level of fading effects, and a large underwater propagation delay. In this paper, in order to tackle those limitations of underwater communications and to make it possible to form a large underwater monitoring systems, we propose a hierarchical underwater network architecture, which consists of underwater sensors, clusterheads, underwater/surface sink nodes, autonomous underwater vehicles (AUVs). In the proposed architecture, for the maximization of packet delivery ratio and the minimization of underwater sensor's energy consumption, a hybrid routing protocol is used. More specifically, cluster members use Tree based routing to transmit sensing data to clusterheads. AUVs on optimal trajectory movements collect the aggregated data from clusterhead and finally forward the data to the sink node. Also, in order to minimize the maximum travel distance of AUVs, an Integer Linear Programming based algorithm is employed. Performance analysis through simulations shows that the proposed architecture can achieve a higher data delivery ratio and lower energy consumption than existing routing schemes such as gradient based routing and geographical forwarding. Start after striking space key 2 times.

• Proceedings of the Korean Information Science Society Conference
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• 2007.10d
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• pp.488-493
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• 2007

헬스케어 응용서비스를 위란 센서 네트워크를 구성하는 노드들은 주로 사람 또는 이동성을 가진 사물이며, 이들간의 상호작용을 통한 헬스케어 응용서비스를 지원하기 위해서는 노드의 동적 기능변경, 동적 자기구성, 에너지 효율성을 고려하여 개발되어야 한다. 이러한 요구사항들은 노드 상에 해당 기능을 수행하는 에이전트를 두어 대상의 이동에 따른 에이전트 전이를 통해 동적 기능변경을 수행 및 처리하고, 이동성을 지원하는 계층적 클러스터링 알고리즘을 적용하여 노드의 이동에 따른 동적 자기구성, 제한된 에너지의 효율성 등을 해결할 수 있다. 본 논문에서는 노드간 에이전트 전이를 통해 동적 기능 변경을 보장하는 Agilla모델 기반 Healthcare Mobility Agent Middleware를 설계하고, 정보 전달의 효율성과 노드의 이동성을 보장하기 위해 LEACH 프로토콜 기반 LEACH_Mobile 프로토콜을 제안한다. 또한 여기서 제안하는 LEACH_Mobile 프로토콜과 Healthcare Mobility Agent Middleware를 연동하기 위한 인터페이스와 LEACH_Mobile 프로토콜을 수행하기 위한 라우팅 모듈을 설계하였다.

• 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.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.4
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• pp.40-48
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• 2007

MANET constructs a network that is free and independent between sensor nodes without infrastructure. Also, there are a lot of difficulties to manage data process, control etc.. back efficiently from change of topology by transfer of sensor node that compose network. Especially, because each sensor node must consider mobility certainly, problem about energy use happens. To solve these problem, mechanisms that compose cluster of cluster header and hierarchic structure between member were suggested. However, accompanies inefficient energy consumption because sensing power level of sensor node is fixed and brings energy imbalance of sensor network and shortening of survival time. In this paper, I suggested intelligent clustering mechanism for efficient energy management to solve these problem of existent Clustering mechanism. Proposed mechanism corresponds fast in network topology change by transfer of sensor node, and compares in existent mechanism in circumstance that require serial sensing and brings elevation survival time of sensor node.Please put the abstract of paper here.