• Journal of KIISE:Computer Systems and Theory
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• v.33 no.9
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• pp.677-683
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• 2006

If a node stops functioning in an ad-hoc wireless network, routing paths involving the node will also fail, when construction of replacement routes is required. A major cause of node failure is energy exhaustion, and route replacements may in turn lead to successive node failures by making more nodes consume their energy. The result could be performance degradation of networks. Therefore it is important to ensure that nodes with limited remaining energy are not included in route construction from the beginning. In this paper we propose a new routing protocol, which takes residue energy of nodes into account in order to prevent node failures resulting from energy shortage. Our routing protocol examines the smallest value of node residue energy ($E_{m}$) from each of all possible routing paths and selects the path which has the largest value of $E_{m}$. We prove, through simulation, that our routing protocol extends the lifetime of nodes which have limited amount of energy, reducing chances of path replacement. It is also shown that our proposed protocol helps alleviate network performance degradation.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11a
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• pp.181-183
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• 2005

Network Reprogramming 에서는 코드 전파가 완료되기까지 걸리는 시간과 에너지 소모가 문제가 된다. 지금까지의 연구들은 에너지 소모를 줄이기 위해서 완료시간을 줄이는 방법에 초점을 두었지만 제한된 에너지를 사용해야 하는 센서 네트워크에서는 전송된 메시지에 의한 에너지 소모도 고려해야 한다. 본 논문에서는 코드 전파 시 전송 메시지 개수를 최소로 하는 DANP를 제시한다. DANP는 각 노드가 이웃 노드에 대한 정보를 이용하여 advertisement 주기를 적절히 늘려서 모든 경우의 Density에 대해서 코드 전파의 효율성을 높인다.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1998.05a
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• pp.49-56
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• 1998

최근 국내의 에너지 수요는 특히 전기에너지 분야에서 급격한 증가추세를 보여왔으며 그 결과 전력생산을 위한 화석연료 중 특히 석탄의 사용량은 해가 갈수록 증가하였으며 이에 따라 다량의 대기오염물질과 온실가스 등이 발생하고 있어서 미래의 석탄 연소시스템들은 높은 열효율과 최소의 대기오염물질 배출을 필요로 하고 있다. (중략)

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1985.04a
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• pp.40-43
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• 1985

• Bulletin of the Korean Space Science Society
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• 1995.10a
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• pp.39-39
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• 1995

• Food preservation and processing industry
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• v.2 no.1
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• pp.71-77
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• 2003

• The monthly packaging world
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• s.179
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• pp.84-87
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• 2008

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.11
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• pp.2022-2028
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• 2017

Recently, the energy shortage of sensors and the leakage of private information are considered as serious problems as the number of sensors is increasing due to the technological advance in Internet-of-Things. RF energy harvesting, in which sensors collect energy from external RF signals, and physical layer security become increasingly important to solve these problems. In this paper, we propose a time switching-based network analog coding for improving information security in wireless networks where the relay can harvest energy from source signals. We formulate 2-hop relay networks where an eavesdropper tries to overhear source signals, and find an optimal time switching ratio for maximizing the minimum required secrecy capacity using mathematical analysis. Through simulations under various environments, it is shown that the proposed scheme improves the minimum required secrecy capacity significantly, compared to the conventional scheme.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.8
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• pp.1444-1451
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• 2016

This paper proposes a Tabu search algorithm to minimize the required energy to send data between a source and a destination using the cooperative communication in wireless ad hoc networks. As the number of nodes in wireless ad hoc networks increases, the amount of calculation for establishing the path between nodes would be too much increased. To obtain the optimal cooperative path within a reasonable computation time, we propose a new Tabu search algorithm for a high-density wireless network. In order to make a search more efficient, we propose some efficient neighborhoods generating operations of the Tabu search algorithm. We evaluate those performances through some experiments in terms of the minimum energy required to send data between a source and a destination as well as the execution time of the proposed algorithm. The comparison results show that the proposed algorithm outperforms other existing algorithms.

• Journal of the Korean Institute of Gas
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• v.2 no.2
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• pp.55-60
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• 1998

In this study, we investigated the dust explosion characteristics by determining minimum ignition energy and explosion limit for this experiment, we used pine-tree dust which was used widely for the filler of thermosetting resin. The experiment was accomplished according to the variation of discharge gap, dust concentration, particle size and humidity. The result of this experiment are as follows; (1) The relation between the discharge gap and ignition energy was that ignition energy decreased according as the discharge gap became small, but increased when the discharge gap was below 4mm and suddenly became infinite when the discharge gap was below. So, we knew that this infinite value was limit discharge gap. (2) When the dust concentration increase and the particle size became microscopic it was easy to explore and in the same particle size, if the humidity increase the minimum ingnition energy decreased.