• Proceedings of the KAIS Fall Conference
• /
• 2010.05a
• /
• pp.45-48
• /
• 2010

에너지 효율성이 중요한 무선 센서 네트워크에서 클러스터링 기술은 클러스터 헤드 노드가 클러스터 멤버 노드의 데이터를 병합하여 싱크노드로 전송함으로써 센서노드들과 싱크노드 사이의 통신 횟수를 줄여 에너지 효율을 얻는다. 이와 관련된 연구로 LEACH(Low Energy Adaptive Clustering Hierarchy) 프로토콜은 센서 네트워크의 데이터 처리 및 전송 부하를 센서 노드 전체에 분산 시켜 무선 센서 네트워크의 수명을 연장 하였다. 본 논문에서는 분산형 클러스터링 라우팅 기법 중 가장 대표적인 LEACH의 클러스터 헤드 결정 방법에 대한 고찰과 이를 토대로 새로운 확률적 클러스터 헤드 결정 방법의 도출을 이루어 내고자 한다.

• Journal of Internet Computing and Services
• /
• v.10 no.1
• /
• pp.159-173
• /
• 2009

Locations of positioned nodes as well as gathered data from nodes are very important because generally multiple nodes are deployed randomly and data are gathered in wireless sensor network. Since the nodes composing wireless sensor network are low cost and low performance devices, it is very difficult to add specially designed devices for positioning into the nodes. Therefore in wireless sensor network, technology positioning nodes precisely using low cost is very important and valuable. This research proposes Cooperative Positioning System, which raises accuracy of location positioning and also can find positions on multiple sensors within limited times. And this research verifies this technology is excellent in terms of performance, accuracy, and scalability through simulation.

• Journal of KIISE
• /
• v.42 no.1
• /
• pp.114-121
• /
• 2015

Large-scale wireless sensor networks are constructed by using a large number of sensor nodes that are non-uniformly deployed over a wide area. As a result, the data collected by the sensor nodes are similar to that from one another since a high density of the sensor nodes may cause an overlap. As a result of the characteristics of the traffic, data is collected from a plurality of sensor nodes by a sink node, and when the sensor nodes transmit their collected data to the sink node, the sensor nodes around the sink node have a higher amount of traffic than the sensor nodes far away from the sink node. Thus, the former sensor encounter bottlenecks due to traffic congestion and have an energy hole problem more often than the latter ones, increasing energy consumption. This paper proposes a congestion control scheme that considers traffic flows in order to control traffic congestion of the sensor nodes that are non-uniformly deployed over a large-scale wireless sensor network.

• Journal of KIISE:Information Networking
• /
• v.34 no.6
• /
• pp.446-457
• /
• 2007

In wireless sensor network, to provide the proper responses quickly for diverse events, wireless sensor nodes have to cooperate with each other. For successful cooperation, the time synchronization among sensor nodes is an important requirement for application execution. In the wireless sensor network, the message packets including time information are used for the time synchronization. However, the transmission of many message packets will exhaust the battery of wireless sensor nodes. Since wireless sensor nodes works on the limited battery capacity, the excessive transmission of message packets has an negative impact upon their lifetime. In this paper, the Reference Interpolation Protocol (RIP) is proposed to reduce the number of message packets for the time synchronization. The proposed method performs the time interpolation between the reference packet's time and the global time of the base station. The proposed method completes the synchronization operation with only 2 message packets when compared to the previous Reference Broadcast Synchronization (RBS) technique. Due to the simple synchronization procedure, our method greatly reduces the number of synchronization messages and showed the 12.7 times less power consumption than the RBS method. From the decrease in the transmission of message packets, the convergence time among wireless sensor nodes is shortened and the lifetime of wireless sensor nodes is also prolonged as much as the amount of saved battery energy.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2014.10a
• /
• pp.96-98
• /
• 2014

Wireless Sensor Network(WSN) is a wireless real-time information(Acquired from the sensor nodes that have the computing power and wireless communication capabilities.) collected, and to take advantage of processing techniques. Currently it is very diverse, such as environmental monitoring, health care, security, smart home, smart grid applications is that. Thus it is required in the wireless sensor network, the algorithm for the efficient use of the limited energy capacity. Suggested by the algorithm for selecting a cluster head node for a hybrid type and clustered, by comparing the amount of energy remaining and a connection between the nodes In this paper, we aim to increase efficiency and accuracy of the wireless sensor network.

• Journal of the Institute of Electronics Engineers of Korea CI
• /
• v.46 no.3
• /
• pp.123-129
• /
• 2009

It is important to locate nodes in the research of wireless sensor network. In this paper, we propose a method that estimates the positions of nodes by using adjacent node information and signal strength in wireless sensor network. With this method, we can find positions of nodes easily because we use Information that nodes have. And we can make a map for all the nodes because we can measure a relative position for an node whose position is not known based on anchor nodes whose positions are already known. In addition, we can confirm whether nodes are placed appropriately. We confirmed that we can locate positions of unknown nodes with small error through verifying the proposed method.

• Proceedings of the Korean Information Science Society Conference
• /
• 2006.10d
• /
• pp.728-733
• /
• 2006

본 논문은 홈 네트워크 환경에서 무선 센서 네트워크를 이용하여 홈 네트워크 서비스를 제공하는 서비스 모델을 제안한다. 제안된 서비스 모델은 댁내에 고정 센서 노드들을 배치하고 사용자에게 부착 가능한 센서 노드로 무선 센서 네트워크를 구성한다. 홈 서버에는 등록된 사용자 선호도 프로파일과 센서 노드들로부터 수집된 데이터를 데이터베이스로 구축한다. 이 데이터를 상황정보로 분석하여 사용자 개개인의 선호도에 따라 댁내 가전기기들을 자동 설정하고 자동 제어하는 서비스를 제공한다. 제안된 방식은 리눅스 환경에서 MySQL 데이터베이스가 내장된 홈 서버와 TinyOS가 탑재된 센서 노드들을 사용하여 구현하고 서비스를 테스트한다.

• Proceedings of the KIEE Conference
• /
• 2007.07a
• /
• pp.1817-1818
• /
• 2007

무선센서네트워크는 컴퓨텅 기술능력과 무선 통신 능력을 지닌 센서 노드들을 이용하여 자율적으로 네트워크를 형성하고 상호간에 정보를 전달한다. 최근 무선센서네트워크 기술이 유비쿼터스 사회의 핵심 기술로 부각되면서 넓은 범위의 지역에서 센싱된 데이터를 활용하는 부분에 많은 연구가 진행되고 있다. 이러한 센서네트워크에서 확장성을 고려하기 위하여 위치기반의 라우팅 기법이 사용된다. 실제위치를 이용한 방법은 GPS를 사용하여 노드의 위치를 파악한다. 그러나 이 방법은 센서노드의 프로세서 및 메모리의 용량을 초과하고, 실내에서 사용할 수 없다는 단점이 있다. 따라서 본 논문에서는 가상좌표(Virtual coordinates) 개념을 이용하여 특정 비콘노드로 부터의 홉수를 계산하여 센서노드의 위치를 계산하고, Greedy 방식의 라우팅을 통하여 실제 위치를 이용한 방법과 비교한다.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.11 no.4
• /
• pp.1272-1277
• /
• 2010

Target detection and tracking wireless sensor network must have various signal processing ability. Wireless sensor nodes need to light weight signal processing algorithm because of energy constraints and communication bandwidth constraints. General signal processing algorithm of wireless sensor node consists of de-noising, received signal strength computation, feature extraction and signal compression. Wireless sensor network life-time and performance of target detection and classification depend on sensor node signal processing. In this paper, we propose energy efficient signal processing algorithm using wavelet transform. The proposed method estimates exact target position.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2008.05a
• /
• pp.477-480
• /
• 2008

In this paper, we design the TCP-Light protocol for directly connecting a sensor network with Internet. When we are monitoring the data and controlling of the sensor node, the sensor network must be connected to Internet. But TCP in wireless networks has a number of performance problems which is high bit-error rates and a hardware constraint. Moreover, the end-to-end acknowledgment and retransmission scheme employed by TCP causes expensive retransmissions along every hop of the path between the sender and the receiver. This paper introduces The TCP-Light protocol which increases TCP performance in wireless sensor networks, decreases the number of end-to-end retransmissions and decreases memory consumption.