• Proceedings of the Korean Information Science Society Conference
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• 2002.04a
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• pp.565-567
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• 2002

인터넷과 무선 이동통신 등이 보편화되면서 두 기술을 접목한 WAP (Wireless Application Protocol)[1]이 등장하였으며, 다수의 사용자 요구를 동시에 효율적으로 처리하면서 다양한 무선 단말기로부터 요청을 신속하게 처리할 수 있는 WAP 게이트웨이(gateway)에 대한 연구가 여러 연구 그룹에서 수행되고 있다. 본 논문에서는 Java의 기본적인 서비스인 멀티쓰레드를 이용하고, 컨테이너 유효 리소스의 효율적 관리를 위해 접속 풀링(connection pooling) 기능과 우선순위 큐를 적용하여 WTP (Wireless Transaction Protocol)[2]를 구현한다. 우선순위에 입각하여 구현된 트랜잭션 서비스를 시뮬레이션을 통하여 성능을 분석한다.

• ETRI Journal
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• v.32 no.5
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• pp.819-822
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• 2010

Supporting QoS over multihop wireless mesh networks is difficult because end-to-end delay increases quickly with the increasing number of hops. This paper introduces a novel multichannel time-division multiple-access media access control (McTMAC) protocol that can help to efficiently reduce delay over multihop networks. Performance evaluation results demonstrate that McTMAC outperforms existing alternative protocols. The max-delay can be reduced by as much as 60% by using McTMAC.

• Journal of The Korean Radiological Technologist Association
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• v.30 no.1
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• pp.77-89
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• 2004

I. 목적 : 의료용 초음파 장비의 성능 관리 중 최적 화질의 기본이 되는 심부 투과 깊이에 대해 검증이 미흡한 장비 회사의 protocol setting 값이 현재 대부분의 병원에서 사용되고 있는 실정이다. 이러한 protocol에서 벗어나 국내 여러 모델의 장치에 공통적으로 환자 검사에 실제로 사용하고 있는 algorithm 인 parameters를 사용하여 초음파 영상에 영향을 미치는 빔 투과 깊이의 변화에 따른 최적영상을 평가하고자 한다. II.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.6
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• pp.1382-1390
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• 2010

A multicast session protocol in wireless networks reduces the session delay of multicast delivery caused by moving of mobile host. A hand-off scheme, called MSDR (multicast session delay reduction), in mobile networks is proposed. MSDR protocol that minimizes the delay of a session re-establishment uses the basic unicast routing function of the IETF mobile IP and the DFA (designated foreign agent) to provide multicast services for mobile hosts. Proposed MSDR protocol allows the mobile hosts to continuously receive packets when they move across the basic sets during hand-off. Discrete-event simulation carried out for performance evaluation of MSDR protocol, and simulation results indicated that our scheme can offer a better performance of multicast session delay reduction in terms of signalling cost than that of IETF.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.9
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• pp.1283-1294
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• 1993

The conventional transport protocols, developed on top of the low-bandwidth high-error network services, exhibit poor performances when operating in the new high-bandwidth low-error networks. A new transport protocol HSTP(High Speed Transport Protocol) was proposed to take advantage of the new network environment. This paper gives a performance evaluation by simulation technique of the proposed HSTP and conventional TP4(Transport Protocol class 4) in their data trans-fer characteristics. The performance variation by HSTP and TP4 are investigated when their various error control techniques are employed, three different techniques for HSTP, and two for TP4. The performance enhancement in HSTP is also evaluated when the rate control technique is used as part of the flow control mechanisms.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.7A
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• pp.727-734
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• 2004

Collision Management Protocol (CMP) efficiently resolves collisions when data frames are transmitted in networks consisting of HomPNA 3.0 asynchronous MAC mode device with random access. Unlike Distributed Fair Priority Queueing (DFPQ) algorithm in HomePNA 2.0 or Binary Exponential Backoff (BEB) algorithm in IEEE 802.11, order of retransmission is decided according to Collision Signaling Sequence (CSS) values allocated to each device. Thus, CMP can minimize the number of mean collisions because order of retransmission is decided in a deterministic way. In this paper. we evaluate the saturation performance of CMP in HomePNA 3.0 using an analytic method.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.8
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• pp.1805-1824
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• 2013

Recently, the use of wireless body area networks (WBAN) has been increasing rapidly in medical healthcare applications. WBANs consist of smart nodes that can be used to sense and transmit vital data such as heart rate, temperature and ECG from a human body to a medical centre. WBANs depend on limited resources such as energy and bandwidth. In order to utilise these resources efficiently, a very well organized medium access control (MAC) protocol must be considered. In this paper, a new, adaptive and energy-efficient MAC protocol, entitled isMAC, is proposed for WBANs. The proposed MAC is based on multi-channel communication and aims to prolong the network lifetime by effectively employing (i) a collision prevention mechanism, (ii) a coordinator node (WCN) selection algorithm and (iii) a transmission power adjustment approach. The isMAC protocol has been developed and modelled, by using OPNET Modeler simulation software. It is based on a networking scenario that requires especially high data rates such as ECG, for performance evaluation purposes. Packet delay, network throughput and energy consumption have been chosen as performance metrics. The comparison between the simulation results of isMAC and classical IEEE 802.15.4 (ZigBee) protocol shows that isMAC significantly outperforms IEEE 802.15.4 in terms of packet delay, throughput and energy consumption.

• The KIPS Transactions:PartC
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• v.15C no.1
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• pp.51-60
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• 2008

Micro-mobility protocols have been developed to reduce the control message overhead due to movements of mobile nodes. With the spread of mobile devices, services using mobile nodes are increasing and multicast services are becoming more important in providing multimedia services. In this paper we propose a new multicast protocol suitable for micro-mobility environments. The proposed protocol is designed to maintain optimal multicast routing paths and continue to provide multicast services without disruption in spite of frequent handoffs due to movements of mobile nodes. We used simulation to evaluate the proposed protocol, compared its performance with existing multicast protocols for mobile environments including bi-directional tunneling, remote subscription, and MMA, and observed that the proposed protocol exhibited better performance in terms of transmission success ratio and overhead on the network.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.16 no.5
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• pp.35-46
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• 2006

The current Internet Key Exchange protocol(IKE) which has been used for key exchange of security system was pointed out the faults of scalability, speed, efficiency and stability. In this research, we tried to resolve those faults, and implemented the newly designed IKEv2 protocol in the IPsec test bed system. In the trend of network expansion, the current Internet Key Exchange protocol has a limitation of network scalability, so we implemented the new Internet Key Exchange protocol as a recommendation of RFC proposal, so as to resolve the fault of the key exchange complexity and the speed of authentication process. We improved the key exchange speed as a result of simplification of complex key exchange phase, and increased efficiency with using the preexistence state value in negotiation phase.

• International Journal of Computer Science & Network Security
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• v.22 no.3
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• pp.236-244
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• 2022

Network Mobility Basic Support (NEMO BS) protocol has been accredited and approved by Internet Engineering Task Force (IETF) working group for mobility of sub-networks. Trains, aircrafts and buses are three examples of typical applications for this protocol. The NEMO BS protocol was designed to offer Internet access for a group of passengers in a roaming vehicle in an adequate fashion. Furthermore, in NEMO BS protocol, specific gateways referred to Mobile Routers (MRs) are responsible for carrying out the mobility management operations. Unfortunately, the main limitations of this basic solution are pinball suboptimal routing, excessive signaling cost, scalability, packet delivery overhead and handoff latency. In order to tackle shortcomings of triangular routing and Quality of Service (QoS) deterioration, the proposed scheme (Diff-FH NEMO) has previously evolved for end-users in moving network. In this sense, the article focuses on an exhaustive analytic evaluation at Home Agent (HA) entity of the proposed solutions. An investigation has been conducted on the signaling costs to assess the performance of the proposed scheme (Diff-FH NEMO) in comparison with the standard NEMO BS protocol and MIPv6 based Route Optimization (MIRON) scheme. The obtained results demonstrate that, the proposed scheme (Diff-FH NEMO) significantly improves the signaling cost at the HA entity in terms of the subnet residence time, number of mobile nodes, the number of DMRs, the number of LFNs and the number of CNs.