• Journal of the Korea Computer Industry Society
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• v.5 no.1
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• pp.101-108
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• 2004

As the dependency to network system and demands of efficient storage systems rapidly grows in every networking filed, the current trends initiated by explosive networked data grow due to the wide-spread of internet multimedia data and internet requires a paradigm shift from computing-centric to data-centric in storagesystems. Furthermore, the new environment of file systems such as NAS(Network Attached Storage) and SAN(Storage Area Network) is adopted to the existing storage paradigm for Providing high availability and efficient data access. We describe the design issues and system components of SANiqueTM, which is the cluster file system based on SAN environment. SANiqueTM has the capability of transferring the user data from the network-attached SAN disk to client applications directly We, especially, present the protocol and functionality of the global buffer manager in our cluster file system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.7B
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• pp.641-649
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• 2004

We propose a dynamic traffic management model which uses adaptive priority reassignment algorithm to deliver service differentiation in home networks, and implement adaptive priority reassignment algorithm using FPGA. The proposed architecture is designed to handle home network traffic without the need for signaling protocol. We categorize home network traffic into three kinds of traffic class: control data traffic class, the Internet data and non-real-time data traffic class, and multimedia data traffic class (include non-real-time and real-time multimedia data traffic). To support differential service about these kinds of traffic class, we designed and implemented a traffic management framework that dynamically change each traffic class priority depending on bandwidth utilization of each traffic class.

• Proceedings of the KIEE Conference
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• 2006.07d
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• pp.1793-1794
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• 2006

네트워크 전력계측 장치는 전국의 수용가 측에 설치되며 전력품질을 감시할 수 있는 단말기와 표준화된 이더넷망(유무선)을 사용한 네트워크 환경과 전국의 전력품질 데이터를 수집할 수 있는 서버로 크게 구성된다. 본 논문에서는 128 샘플링으로 계측되는 전력품질계측 단말기를 구현하고 전력품질 분석 알고리즘을 고안하였으며 이더넷망을 이용하여 전력품질 데이터를 수집하고 수집데이터를 분석하여 전력 품질에 대한 분석을 하였다. 뿐만아니라 전력품질에 영향을 주는 고조파신호들과 OVER/UNDER 전압과 전류 및 주파수, SAG, SWELL, INTERRUPT등을 인식하여 해당 데이터를 메모리에 저장하는 일련의 알고리즘을 연구하였으며 이렇게 저장된 정보를 이더넷망에서 무결성과 신뢰성이 있게 고속으로 전송받을 수 있는 통신 프로토콜에 관한 연구가 수행하였다. 뿐만 아니라 응용프로그램에서 소프트에웨어적인 필터링 기법과 분석알고리즘을 연구하여 이상신호에 대한 원인 판단이 가능하도록 연구한다. 본 논문은 네트워크(인터넷/이더넷)와 전력품질계측 관련 방법론과 SERVER개념을 도입한 유비쿼터스에서 센서네트워크 기법을 전력산업에 융합하려는 연구에 그 요점이 있다.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.1
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• pp.21-28
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• 2009

In this paper, we consider the Femtocell based enterprise wireless network using 2G/3G/4G cellular network technologies. And, we apply the open network service API which enable an easy development of ISP or enterprise services to P2P enterprise services. Based on the proposed scheme, enterprise services can be always connected at anywhere and anytime via heterogeneous devices. By using a qualitative analysis, we evaluate the performance of the proposed scheme and compare with that of the famous P2P service - Skype. Results show that the proposed scheme requests smaller servers and flows with enhanced service quality.

• 한국정보통신설비학회:학술대회논문집
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• 2009.08a
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• pp.81-85
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• 2009

본 논문은 VoIP, IPTV, VoD 등의 실시간 서비스 품질을 네트워크 노드에서 모니터링함으로써네트워크에서 발생한 품질이상을 분석할 수 있는 스위치 칩을 설계하였다. 인터넷 서비스의 특성상 단대단 서비스에 기반한 실시간서비스는 품질이상이 발생한 위치를 정확하게 분석할 수 없기 때문에 유지보수에 어려움이 있다. 이러한 문제를 해결하기 위해 본 논문에서는 실시간서비스에 해당하는 플로우를 등록하고 해당 플로우가 장치내에서 발생한 패킷손실, RTP 시퀀스 넘버를 참조하여 이전 장치에서의 패킷손실, 패킷의 IAT(Inter Arrival Time), 대역폭, 그리고 장치내 지연을 실시간으로 측정할 수 있는 기능을 가진 AVB(Audio/Video Bridge)칩을 구현하기 위해 IEEE802.1AS를 기만한 시간동기 프로토콜의 정확성을 시뮬레이션하고, FPGA를 이용하여 구현한 AVB 스위치칩에서 타임스템프의 정확성을 확인함으로써 실시간서비스의 품질을 네트워크에서 실시간으로 모니터링 할 수 있는 가능성을 확인하였다.

• The KIPS Transactions:PartC
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• v.9C no.3
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• pp.367-374
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• 2002

IPsec offers not odd Internet security service such as Internet secure communication and authentication but also the safe key exchange and anti-replay attack mechanism. Recently IPsec is implemented on the various operating systems. But there is no existing tool that checks the servers, which provide IPsec services, work properly and provide their network security services well. In this paper, we design and implement the rule based security evaluation system for IPsec engine. This system operated on Windows and UNX platform. We developed the system using Java and C language.

• Journal of the Korea Computer Graphics Society
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• v.3 no.1
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• pp.29-36
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• 1997

Most Virtual Reality Systems have been developed to support only a single user on a stand-alone system. With increasing availability of Internet, many people are taking strong interests in distributed Virtual Reality : the virtual environment is shared by many paticipants interacting over the network. To support sharing virtual environment and interactions on a network, we developed novel contributions to 3D world description and a network model. Interactive 3D world description is based on VRML, which is extended to support multi-user interactions. Then network model in our system consists of an architecture and a set of protocols for realizing a multi-user interactive shared 3D environment in IP multicast environment.

• 대한공업교육학회지
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• v.33 no.2
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• pp.248-258
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• 2008

Current Internet uses HTTP (Hyper Text Transfer Protocol) as an application layer protocol and TCP (Transmission Control Protocol) as a transport layer protocol to provide web service. SCTP (Stream Control Transmission Protocol) is a recently proposed transport protocol with very similar congestion control mechanisms as TCP, except the initial congestion window during the slow start phase. In this paper, we present a mathematical model of object transfer latency during the slow start phase for HTTP over SCTP and compare with the latency of HTTP over TCP. Validation of the model using experimental result shows that the mean object transfer latency for HTTP over SCTP during the slow start phase is less than that for HTTP over TCP by 11%.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.990-994
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• 2003

This paper describes the VoIP(Voice over Internet Protocol) SoC(System on Chip) Design and the test board development for the function verification to support voice communication services using Internet. To implement the simple system of configuration, we designed the VoIP SoC which have ARM922T of 32bit microprocessor, IP network interface, voice signal interface, various user interface function. Also we developed test program and communication protocol to verify the function of this chip. We used several tools of design and simulation, developed and tested a test board with Excalibur which includes ARM922T microprocessor and FPGA.

• The KIPS Transactions:PartC
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• v.11C no.1
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• pp.89-98
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• 2004

AQM (Active Queue Management) techniques such as RED (Random Early Detection) which be proposed to solve the congestion of internet perform congestion control effectively for TCP data. However, in the situation where TCP and UDP share the bottleneck link, they can not solve the problems of the unfairness and long queueing delay. In this paper, we proposed an simple queue management algorithm, called PSRED (Protocol Sensitive RED), that improves fairness and decreases queueing delay. PSRED algorithm improves fairness and decreases average queue length by distinguishes each type of flow in using protocol field of packets and applies different drop functions to them respectively.