• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.11
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• pp.1267-1276
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• 2014

As the volume of internet rapidly increases, the number of IPv4 addresses available is quickly declining, while transition to IPv6 is being delayed. As a interim solution, Variable-Length Subnet Masking(VLSM) addressing scheme, which varies the length of each IP address allowing more efficient, is being used. This paper suggests effective example of network based on virtual network with topology designed using VLSM charting rather than usual theoretical approach in VLSM, which allows more efficient use of address space.

• Journal of the Korea Society of Computer and Information
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• v.13 no.2
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• pp.177-183
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• 2008

In this paper we suggest a hybrid MAC protocol for wireless sensor networks (WSN) to enhance network performance. The proposed MAC scheme is specifically designed for wireless sensor networks which consist of lots nodes. The contributions of this paper are: First, the proposed scheduling algorithm is independent of network topology. Even though the BS node has lots of one hop node in dense mode network, all the time slots can be assigned fully without increasing frequencies. Second, BS one hop nodes can use more than one time slots if necessary, so total network performance is increased. We compare the network performance of the proposed scheme with previous one, HyMAC [1].

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.3
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• pp.537-543
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• 2012

Smart home System is shirt-sleeve, the automatic control systems, computer network system and network communication technology in the integration of network intelligent home control system. Intelligent household will let users have a more convenient means to management of domestic equipment, for example, through the house, wireless remote control, touch screen phone and Internet or speech recognition control household devices, more can perform scene operation, make more equipment form linkage. In this paper, we propose the intelligent household various kinds of equipment within each other can communication, do not need to user command according to different state interactive operation, thus to bring the greatest degree of user efficient and convenient, comfortable and safe.

• Proceedings of the Korea Multimedia Society Conference
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• 2002.05d
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• pp.1012-1016
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• 2002

분산시스템에서 부하균형을 유지하기 위해서는 네트워크상의 각 노드는 다른 노드들의 부하상태정보를 가져야만 한다. 네트워크상에 ν개의 노드가 존재할 때 모든 노드간에 부하상태정보를 교환하기 위해서는 Ο(ν²)의 트래픽 오버헤드가 필요하게 된다. 이 논문에서는 분산된 노드간에 동기적으로 동작하는 부하균형 알고리즘을 제시한다. 이를 위해 먼저 SBIBD(symmetric balanced incomplete block design)에 근거하여 (ν,k,1)-configuration에 의해 ν=k²-k＋1개의 노드를 갖는 네트워크 토폴로지를 구성하였다. 이 망에서 동작하도록 고안된 부하상태정보 전파 알고리즘은 (equation omitted)의 메시지 오버헤드를 가지면서 각각의 노드가 ν개의 모든 노드에 대한 부하상태정보를 가지도록 한다. 또한 이 부하균형 알고리즘은 모든 링크가 부하상태정보 전송을 위해 동일한 트래픽을 갖도록 설계되었다.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10d
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• pp.391-394
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• 2006

무선 센서 네트워크에서 각 센서 노드는 에너지의 한계를 가지기 때문에, 에너지 소비문제는 매우 중요한 이슈이다. 조밀한 환경의 센서 네트워크에서 모든 노드들이 센싱에 참여한다면, 센싱영역의 중복영역이 커지게 되고, 이로 인해 불필요한 에너지를 소비하게 된다. 본 논문에서는 connectivity 와 coverage 를 보장할 수 있고, 효율적으로 활성화 노드를 선택할 수 있는 기법을 제안하여, 불필요한 센서 노드들의 에너지소비를 막아 전체적인 네트워크의 lifetime 을 연장시키고자 한다.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.157-158
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• 2006

무선 센서 네트워크에서 각 센서 노드는 에너지의 한계를 가지기 때문에, 에너지 소비문제는 매우 중요한 이슈이다. 조밀한 환경의 센서 네트워크에서 모든 노드들이 센싱에 참여한다면, 센싱영역의 중복영역이 커지게 되고, 이로 인해 불필요한 에너지를 소비하게 된다. 본 논문에서는 WSN 에서 connectivity 와 coverage 를 보장할 수 있는 효율적인 활성화 노드를 선택하는 기법을 제안하여, 불필요한 센서노드들의 에너지소비를 막고 전체적인 네트워크의 lifetime 을 연장시키고자 한다

• Proceedings of the Korea Information Processing Society Conference
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• 2010.04a
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• pp.95-98
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• 2010

OpenFlow 는 인터넷 스위치(라우터 포함)를 부분적으로 개선하여 연구자가 기존 네트워크의 정상적인 서비스를 간섭하지 않으면서 새로운 네트워킹 기술을 테스트할 수 있는 미래인터넷 (Future Internet) 연구를 위한 프로토콜이다. 하지만 OpenFlow 기반 테스트베드의 상태 정보를 확인하고 발생한 플로우들을 제어할 수 있는 도구(tool)가 부족하여, 연구자가 실험의 다양성을 제공 받기 어렵다. ENVI(Extensible Network Visualization & Control Framework)는 OpenFlow 네트워크 가시화를 위한 프레임워크로, 사용자의 목적에 맞는 인터페이스를 만들도록 제공해 준다. 본 논문에서는 OpenFlow 기반 테스트베드의 토폴로지 정보 및 플로우 상태를 쉽게 확인하고, 플로우 경로를 제어하는 OpenFlow 제어기 응용의 개발과 ENVI 의 확장을 설계하고 이를 구현을 통해 검증한다.

• Journal of KIISE:Information Networking
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• v.34 no.5
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• pp.328-339
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• 2007

Conventional topology-based routing protocols are not suitable for inter-vehicular communication, where frequent route updates are necessary due to continuous and abrupt changes in network topology Position-based routing protocols are widely accepted to better serve their purpose in such a scenario as they do not require path discovery or maintenance. However they have to deal with the overhead of the location service and inaccurate position information. This paper proposes the MMFP (Multi-hop MAC Forwarding Protocol) for inter-vehicle communication that relies on reachability information collected from received packets in making a forwarding decision without path discovery. The MMFP is designed as an extension to the IEEE 802.11 MAC layer to ensure accuracy in its time-critical operations. This paper also presents some simulation results that demonstrate the superior performance of the MMFP over AODV in a realistic inter-vehicular communication.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.6
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• pp.259-267
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• 2002

In this paper, we focus on comparison and analysis of performance for existing Topology Aggregation algorithm. For these, we designed and implemented PNNI routing simulator which contain various TA schemes, and evaluate performance of TA schemes by this simulator. The PNNI 1.0 specification of the ATM Forum is recommended that hierarchical routing protocol and topology information is aggregated in the network constructed hierarchically Aggregating topology information is known as TA(Topology Aggregation) and TA is very important for scalability and security in network. Therefore, the performance of PNNI network would vary with TA schemes and routing algorithm. PNNI routing simulator can be applied to develope Routing algorithm and TA algorithm and can be develope these algorithms in short period.

• The Journal of the Korea Contents Association
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• v.13 no.1
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• pp.40-47
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• 2013

To verify the condition of patients moving in the medical center like hospital needs to be consider the various wireless communication network protocols and network components. Wireless communication protocols such as the 802.11a, 802.11g, and direct sequence has their specific characteristics, and the various components such as the number of mobile nodes or the distance of transmission range could affects the performance of the network. Especially, the network topologies are considered the characteristic of the brain wave(EEG) since the condition of patient is detected from it. Therefore, in this paper, various wireless communication networks are designed and simulated with Opnet simulator, then evaluated the performance to verify the wireless network that transmits the patient's EEG data efficiently. Overall, the 802.11g had the best performance for the wireless network environment that transmits the EEG data. However, there were minor difference on the performance result depends on the components of the topologies.