• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.7
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• pp.1721-1736
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• 2013

Black and gray hole attack is one kind of routing disturbing attacks and can bring great damage to the network. As a result, an efficient algorithm to detect black and gray attack is important. This paper demonstrate an adaptive approach to detecting black and gray hole attacks in ad hoc network based on a cross layer design. In network layer, we proposed a path-based method to overhear the next hop's action. This scheme does not send out extra control packets and saves the system resources of the detecting node. In MAC layer, a collision rate reporting system is established to estimate dynamic detecting threshold so as to lower the false positive rate under high network overload. We choose DSR protocol to test our algorithm and ns-2 as our simulation tool. Our experiment result verifies our theory: the average detection rate is above 90% and the false positive rate is below 10%. Moreover, the adaptive threshold strategy contributes to decrease the false positive rate.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06d
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• pp.308-310
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• 2012

최근 무선 센서 네트워크 환경에서 대용량 멀티미디어 데이터에 대한 요구가 증가하면서 통신 대역폭 및 한정적인 에너지의 한계를 극복하기 위한 대안으로 데이터 분할 및 다중 경로 기법들이 제안되었다. 기존 기법들은 데이터 전송 시에 발생하는 부하의 분산을 통해 네트워크의 성능을 향상시킬 수 있다는 것을 증명하였지만, 데이터의 효율적인 분할과 악의적인 공격에 의한 보안성 문제에 대해서 고려하지 않았다. 이러한 문제점을 해결하기 위해 본 논문에서는 비트평면 분할 기반의 보안성 있는 비-중첩 다중경로 라우팅 기법을 제안한다. 제안하는 기법은 멀티미디어 데이터를 비트평면 단위로 분할하여 다중 경로로 전송함으로써 기존의 키 기반의 암호화 기법을 사용하지 않고도 전체 네트워크에 대한 보안성을 향상 시켰다. 또한 경로 상 노드들의 잔여 에너지를 고려하여 데이터 전송을 수행함으로써 전체 네트워크의 에너지 효율성을 향상시켰다. 성능평가 결과, 제안하는 기법은 기존 기법에 비해 노드의 생존율이 평균 50% 이상 향상되었고, 데이터가 노출되더라도 해당 패킷을 가지고 본래 이미지를 복구하는 것이 불가능하기 때문에 높은 보안성을 제공한다.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06d
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• pp.199-201
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• 2012

무선 멀티미디어 센서 네트워크를 활용하기 위한 응용에서는 대용량 멀티미디어 데이터 저장 및 처리 기술, 데이터 전송 기술 등과 같은 다양한 기반 기술들이 요구된다. 특히, 응용을 실제 환경에 적용하기 위해서는 대용량 데이터에 대한 데이터 보안 기술은 필수적이다. 본 논문은 여러 해킹 기술 중 하나인 스니핑 공격으로부터 원천적인 방어를 위해, 데이터 전송 경로를 위험 요소로부터 물리적으로 회피시키기 위한 다중 경로 라우팅 기법을 제안한다. 제안하는 기법은 위험 요소의 감지 반경과 움직임을 토대로 위험 요소의 인근에 위치한 센서 노드에 준비태세 단계를 설정한다. 이를 기반으로 데이터의 우선 순위를 설정하여 데이터 라우팅 과정에서 준비태세 단계와 데이터의 우선 순위를 고려하여 우선순위에 맞는 안전한 경로를 통해 위험요소 우회 다중 경로 라우팅을 수행한다. 시뮬레이션을 통해 제안하는 기법의 구현 가능성을 제시하였으며, 준비태세를 기반으로 효과적인 위험요소 우회 다중 경로 라우팅을 보였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.5B
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• pp.762-770
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• 2010

The researches about energy efficieny of wireless sensor MAC protocol is an issue in present days. Therefore, MAC and routing protocols for reducing energy consumption at sensor nodes is needed. In this study, a low-power MAC protocol for sensor network is proposed, which in based on X-MAC by exploiting virtual synchronization. The virtual synchronization technique lets senders postpone packet transmission until receivers' wake-up time, so that senders transmit only one or two short preambles. Using NS-2, a proposed MAC protocol improve the energy efficiency by 10% compared with the X-MAC protocol.

• Water for future
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• v.27 no.4
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• pp.95-104
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• 1994

The sinuosity model has been developed to simulate to developed to simulate the floodwave in meandering channels by solving the extended Saint-Venant equation with the Preissmann scheme. The suggested model is compared with three conventional floodplain routing methods in terms of governing equations, mass conservation error and floodwave analysis. The sinuosity model produces the mass conservation error of 1.5-1.8%, however the separate channel model produces 9.1% and 27.4% for sinuosity of 1.5 and 2.0, respectively. The model has been used to simulate flow in an idealized meandering river with a floodplain. The attenuation ratio and the travel time ratio are found to increase as the floodplain roughness and width increase and as the sinuosity factor decreases. The model is expected to contribute the floodwave analysis in sinuous channel with compound corss sections.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.10 no.4
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• pp.121-127
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• 2011

Many peer-to-peer (p2p) systems have been studied in distributed, ubiquitous computing environments. Distributed hash table (DHT)-based p2p systems can improve load-balancing even though locality utilization and user mobility are not guaranteed. We propose a mobile locality-based hierarchical p2p overlay network (MLH-Net) to address locality problems without any other services. MLH-Net utilizes mobility features in a mobile environment. MLH-Net is constructed as two layers, an upper layer formed with super-nodes and a lower layer formed with normal-nodes. Because super-nodes can share advertisements, we can guarantee physical locality utilization between a requestor and a target during any discovery process. To overcome a node failure, we propose a simple recovery mechanism. The simulation results demonstrate that MLH-Net can decrease discovery routing hops by 15% compared with JXTA and 66% compared with Chord.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.6
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• pp.1187-1193
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• 2003

The interest for IPv6, which is next generation IP, increases, while the difficulty for adopting it into IT industries also increases too. We also expect that Internet technologies develop on basis of All-IP networks, which include various heterogeneous networks. Therefore, it is necessary for network to support mobility and multicast capability to create applications with wide-variety. In this paper, we propose a new mobile multicasting protocol called Mobile IPv6 Multicast Protocol(MIMP). The proposed scheme satisfies no packet losses from roaming and optimal routing efficiency.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.2
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• pp.77-83
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• 2010

Vehicular Ad Hoc Networks are self-organizing Peer-to-Peer networks that typically have highly mobile vehicle nodes, moving at high speeds, very short-lasting and unstable communication links. VANETs are formed without fixed infrastructure, central administration, and dedicated routing equipment, and network nodes are mobile, joining and leaving the network over time. So, VANET-security is very vulnerable for the intrusion of malicious and misbehaving nodes in the network, since VANETs are mostly open networks, allowing everyone connect, without centralized control. In this paper, we propose a rough set based anomaly detection method that efficiently identify malicious behavior of vehicle node activities in these VANETs, and the performance of a proposed scheme is evaluated by a simulation in terms of anomaly detection rate and false alarm rate for the threshold ${\epsilon}$.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.6
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• pp.528-534
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• 2013

The energy consumption problem should be taken into consideration in wireless sensor network. Many studies have been proposed to address the energy consumption and delay problem. In this paper, we propose BISA(Bio-inspired Scheduling Algorithm) to reduce the energy consumption and delay in wireless sensor networks based on biological system. BISA investigates energy-efficient routing path and minimizes the energy consumption and delay using multi-channel for data transmission by multiplexing data transmission path. Through simulation, we confirm that the proposed scheme guarantees the efficient energy consumption and delay requirement.

• Journal of the Korean Society of Marine Environment & Safety
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• v.11 no.2 s.23
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• pp.9-17
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• 2005

In the present maritime traffic conditions of Gwangyang harbor, there exists many hazardous factors which may lead to huge accidents including marine oil pollution. To mitigate the danger to vessels in Gwangyang harbor and to secure the safety of maritime environment, we established one way traffic between No.3 Route and No.4 Route, Designed of deep water line on No.3 route, Extended one-way route for Myo-Do Passage etc.