• 한국정보통신설비학회:학술대회논문집
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• 2005.08a
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• pp.313-317
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• 2005

The network ingress filtering is a simple and efficient method for preventing IP source spoofing of fixed nodes. Since mobile hosts cannot communicate with its correspondent nodes if the network ingress filtering is configured in mobile IPv4 network, reverse tunneling was considered as a method for avoiding network ingress filtering. But, unfortunately this method does not solve IP source spoofing of mobile nodes. In this paper, we propose a simple and efficient method for preventing IP source spoofing of mobile nodes assuming that only the mobile hosts connected to foreign agents and the network that foreign agent manages is small.

• 한국정보통신설비학회:학술대회논문집
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• 2003.08a
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• pp.240-243
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• 2003

본 논문에서는 Agere Systems사의 네트워크 프로세서를 사용한 고성능 IP-DiffServ/IP-MPLS 시스템의 구조를 제안하고 성능을 분석한다. 제안한 시스템은 기가비트 이더넷 뿐만 아니라 ATM과 POS 등 다양한 인터페이스를 제공하며 코어 및 에지 라우터로서 MPLS LER 또는 LSR로의 역할을 수행한다. 성능분석은 OPNET을 사용하여 시스템을 모델링한 후 입력 트래픽에 대해서 DiffServ 클래스별 지연시간과 지연의 주된 원인을 분석한다. 그리고 이를 바탕으로 시스템의 성능을 극대화할수 있는 네트워크 프로세서의 최적 파라메터를 도출한다. 성능분석 결과, 시스템이 각 서비스 클래스에 대해서 원활한 서비스를 제공하기 위해서는 프리미엄 서비스에는 최고의 우선순위를 부여하여 큐에 데이터 블럭들이 찰 때 마다. 즉시 서비스해 주어야 한다는 것을 알 수 있었다. 그리고 트래픽이 특정 출구 라인카드로 몰리는 핫스팟이 발생할 경우 트래픽의 지연이 증가하게되는데 이 지연의 주요 원인은 출구 라인카드에서의 큐잉에 의한 것임을 알 수 있었다.

• Journal of the Korea Institute of Military Science and Technology
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• v.11 no.1
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• pp.25-32
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• 2008

In this paper, we propose how to efficiently apply IP and TDL(Tactical Datalink) protocol to the Link-K network for using their applications on the host system. We classify 3 kinds of communication method between IP network and TDL network. We explain the concepts of Like-to-Like communication (Link-K over IP, IP over Link-K) and Any-to-Any communication. We describe the characteristics and the implementation range of tactical datalink processor for each communication method.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.2
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• pp.143-149
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• 2010

Bandwidth and Buffer are critical network resources to determine the end-to-end quality of service. In this paper, we investigate several techniques on bandwidth and buffer management and classify them according to the types they used for controlling the throughput of a TCP/IP network. Moreover, in this paper, it present a new approach for modeling the active bandwidth and buffer control mechanisms for TCP/IP networks.

• Speech Sciences
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• v.11 no.4
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• pp.67-73
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• 2004

Packet loss, jitter, and delay in the Internet are caused mainly by the shortage of network bandwidth. It is due to queuing and routing process in the intermediate nodes of the packet network. In the Internet whose bandwidth is changing very rapidly in time depending on the number of users and data traffic, controlling the peak transmission bit-rate of a VoIP. system depending on the channel condition could be very helpful for making use of the available network bandwidth. Adapting packet size to the channel condition can reduce packet loss to improve the speech quality. It has been shown in [1] that a VoIP system with an AMR speech codec provides better speech quality than VoIP systems with fixed rate speech codecs. With the adaptive codec mode assignment. algorithm proposed in [1], in this paper, we performed the voice transmission experiments using the wireless LAN through the real Internet environment. Experimental results are analyzed and discussed with our findings.

• Proceedings of the Korea Contents Association Conference
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• 2004.11a
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• pp.275-279
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• 2004

In this paper, a large-scale, wide-area storage system based on IP is proposed which is under development. OASIS is a storage system enforced with very high-scalability up to hundreds and thousands of clients over IP network, and it is able to extend the service to the wide area network. For this purpose, we adopt an storage interconnection technology based on IP, the object based storage technology and a clustered server architecture which provides high-scalability and availability to our system. This system can be utilized to provide network storage service which gains more reality with the incoming FTTH and WiBro services.

• The Journal of the Korea Contents Association
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• v.2 no.3
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• pp.119-126
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• 2002

The QoS(Quality of Service) guarantee mechanism is one of critical issues in the wireless network. Real-time applications like VoIP(Voice over IP) in All-IP networks need smooth handoffs in order to minimize or eliminate packet loss as a Mobile Host(MH) transitions between network links. In this paper, we design a new multicasting algorithm using DB(Dynamic Buffering) mechanism for Mobile-IPv6. A key feature of the new protocol is the concepts of the DB and MRA(Multicast Routing Agent) to reduce delivery path length of the multicast datagram. Particularly, the number of tunneling and average routing length of datagram are reduced relatively, the multicast traffic load is also decreased.

• Journal of Advanced Navigation Technology
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• v.13 no.5
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• pp.749-755
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• 2009

This paper described the design and implementation of the FRA(Fault Recovery Agent) for home network environment based on IP-USN. This system consists of a FDA, FSA, and FRA. FDA is an agent that detects an fault by hooking techniques for multimedia distance education based on IP-USN environment. FSA is an agent that is an fault sharing system for multimedia distance education based on IP-USN environment. FRA is a system that is suitable for recovering software fault for multimedia distance education running on home network environment based on IP-USN. It is necessary for the system to be protected by reactivity of media service instance instead of breaking process of session. This system is limited only for FRA modeling.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.5
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• pp.1115-1122
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• 2012

VoIP service is steadily growing due to the spread of smartphones, enhanced network, and various VoIP applications. But, VoIP has many security vulnerabilities because it is based on IP network. This paper analyzes the important weight of VoIP security checklists for incident prevention and response using AHP. The results of AHP analysis showed that network security, incident response, and access control were the most important in technical, administrative, physical standpoint. This study proposes factor analysis of VoIP security checklist at first time. By doing this, it will be used helpfully when VoIP service providers establish their own security policies and inspect their VoIP environment according to their security policies.

• Annual Conference of KIPS
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• 2010.04a
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• pp.581-584
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• 2010

Based on superspeed nation-wide communication infrastructure, high speed and high quality ALL IP communication network is created. It is a point in time where such infrastructure allows residential and commercial phones to be ported from PSTN to IP network. The problem experienced on IP phones in ALL IP environment and IMS server products are not easily approachable and dealt with. Therefore, this paper discusses approaches used in analyzing and resolving problems before they actually occur. This paper first discusses briefly the IP phones used in IMS network and their related problems. Then next topic deals with characteristics of these problems and current status. Last but not least, the causes of the problems are analyzed and solutions to these problems are introduced. Also discussed are solutions to possible future issues followed by conclusion.