• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.203-206
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• 2009

Because the meteorological observation towers are scattered over large area, the collected meteorological data are very sparse. Therefore, the need for data collection on the limited urban areas like a specific building or subway area brings about vest cost which is required to install the corresponding sensors on the areas. Recently, to overcome this problem, the sensor network technique comes to the fore. This paper studies an application to service the meteorological map using mobile phone sensors.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.1077-1080
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• 2009

Dense meteorological data are hard to be collected on the limited urban areas because of vest cost which is required to install the corresponding sensors on the areas. Recently, to overcome this problem, the sensor network technique comes to the fore. This paper studies an application to service the meteorological map using mobile phone sensors. A design results for system implementation are introduced in this paper.

• Proceedings of the Korea Information Processing Society Conference
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• 2010.11a
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• pp.929-932
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• 2010

센서의 특징은 사람이 측정하기 힘든 지역이나 장시간 측정해야 할 지역의 정보를 수집하기에 효과적이다. 이런 센서의 특징은 산불지역의 예방 및 방재에 사용하기에 알맞다. 산불 감시는 광범위한 지역 및 장시간을 감시해야 하는 특징을 갖고 있다. 산불감시의 특징과 센서의 특징은 어떻게 보면 같은 특징을 갖는 것을 알 수 있다. 본 논문에서는 센서들 간의 네트워크를 구축하여 서로의 정보를 교환하여 산불의 발화점 및 앞으로 산불이 일어날 지역을 예측을 통하여 초기 진압에 대한 센서 네트워크 구조를 제시한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.938-941
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• 2009

디지털 선박 건조에 관심이 높아짐에 따라 선박 내에 USN(Ubiquitous Senser Network)의 구축이 요구되며, 센서 노드와 서버의 응용 프로그램 사이에서 중간 역할을 담당하는 선박USN 미들웨어가 필요하다. 일반 USN 미들웨어와는 달리 선박USN 미들웨어는 선박이라는 특수환경을 고려하여 설계되어야 한다. 선박은 해상운송수단이므로, 보다 높은 안전성의 확보가 필요하고 제한된 자원의 공급으로 인해 효율적인 자원 관리가 필요하기 때문이다. 본 논문에서는 이러한 요소들을 고려한 선박USN 미들웨어를 설계한다. 설계한 USN 미들웨어는 상황인식을 통해 데이터의 거짓 유무를 판별하여 불필요한 데이터 전송을 차단하여 에너지 효율적인 특성을 갖는다.

• Convergence Security Journal
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• v.12 no.6
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• pp.25-30
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• 2012

As the network composed of numerous sensor nodes, sensor network conducts the function of sensing the surrounding information by sensor and of the sensed information. Our military has also developed ICT(Information and Communication Technology) along with the methods for effective war by sharing smooth information of battlefield resources through network with each object. In this paper, a sensor network is clustered in advance and a cluster header (CH) is elected for clusters. Before deployment, a certificate is provided between the BS and the sensor nodes, and after clustering, authentication is done between the BS and the sensor nodes. Moreover, inter-CH authentication technique is used to allow active response to destruction or replacement of sensor nodes. Also, because authentication is done twice, higher level of security can be provided.

• The Journal of the Korea Contents Association
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• v.12 no.3
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• pp.55-66
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• 2012

In wireless sensor networks, a positioning scheme is one of core technologies for sensor applications such as disaster monitoring and environment monitoring. The One of the most positioning scheme, called DV-HOP does not consider non-uniform sensor networks that are actual distributed environments. Therefore, the accuracy of the existing positioning scheme is low in non-uniform network environments. Moreover, because it requires many anchor nodes for high accuracy in non-uniform network environments, it is expensive to construct the network. To overcome this problem, we propose a novel sensor positioning scheme using density probability models in non-uniform wireless sensor networks. The proposed scheme consists of the density probability model using the deployment characteristics of sensor nodes and the distance refinement algorithm for high accuracy. By doing so, the proposed scheme ensures the high accuracy of sensor positioning in non-uniform networks. To show the superiority of our proposed scheme, we compare it with the existing scheme. Our experimental results show that our proposed scheme improves about 44% accuracy of sensor positioning over the existing scheme on average even in non-uniform sensor networks.

• The Journal of the Korea Contents Association
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• v.13 no.2
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• pp.52-61
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• 2013

In wireless sensor networks, the geographical positioning scheme is one of core technologies for sensor applications such as disaster monitoring and environment monitoring. For this reason, studies on range-free positioning schemes have been actively progressing. The density probability scheme based on central limit theorem and normal distribution was proposed to improve the location accuracy in non-uniform sensor network environments. The density probability scheme measures the final positions of unknown nodes by estimating distance through the sensor node communication. However, it has a problem that all of the neighboring nodes have the same 1-hop distance. In this paper, we propose an efficient sensor positioning scheme that overcomes this problem. The proposed scheme performs the second positioning step through the sensing range control after estimating the 1-hop distance of each node in order to minimize the estimation error. Our experimental results show that our proposed scheme improves the accuracy of sensor positioning by about 9% over the density probability scheme and by about 48% over the DV-HOP scheme.

• The Journal of the Korea Contents Association
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• v.12 no.4
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• pp.60-68
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• 2012

In recent years, the requirements on the high quality environment monitoring by using the sensor nodes which can handle the multimedia data in WSN have been increased. However, because the volume of multimedia data is tremendous, the limited bandwidth of a wireless channel may incur the bottleneck of a system. To solve such a problem, most of the existing distributed multi-path routing protocols based on multimedia data just focused on overcoming the limited bandwidth in order to enhance the energy efficiency and the transmission rate. However, because the existing methods can not apply a key-based technique to encrypt the multimedia data, they are very weak for the security. In this paper, we propose a secure disjointed multipath routing scheme for multimedia data transmission. Since our proposed scheme divides multimedia data(eg. image) into pixels and sends them through disjointed multipath routing, it can provide security to the whole network without using the key-based method. Our experimental results show that our proposed scheme reduces about 10% the amount of the energy consumption and about 65% the amount of the missed data packets caused by malicious nodes over the existing methods on average.