• Journal of KIISE:Computer Systems and Theory
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• v.30 no.11
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• pp.675-690
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• 2003

In this paper, we present the virtual dancing studio for distributed virtual environment. In this system, geographically distributed user shares the virtual dancing hall and interacts with each other. The participating object can be a graphical avatar or a live video stream. It allows the coexistence of graphic objects and real images in the shared virtual space. One of the main technical challenges in developing the distributed virtual environment is to handle excessive network traffic. In an effort to effectively reduce the network traffic, we propose a scheme to adjust the QoS of each object with respect to the distance from the observer in the virtual space. The server maintains the QoS vector for each client's shared space and controls the packet traffic to individual clients based on its QoS vectors. We develop a proto-type virtual dancing environment. Java based development enables the client to be platform independent. The result of experiment shows that the adoption of hierarchical QoS management significantly reduces the overall network traffic.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.11b
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• pp.1439-1442
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• 2002

MPLS 기술은 빠른 패킷스위칭 뿐아니라 VPN 이나 QoS를 보장하기에 적절한 기술로 알려져 있다. 본 논문에서는 QoS 보장 서비스를 제공하기 위한 MPLS 시스템의 소프트웨어 구조를 제시하고자 한다. 먼저 각 블록 별로 요구되는 기능들에 대해 정의하고, 블록간의 인터페이스 기능들을 정의한다. 또한 구현 측면에서 고려되어야 할 부분들을 검토하고 전체적인 소프트웨어 구조를 제시하고자 한다.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04d
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• pp.635-637
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• 2003

복잡한 소프트웨어가 필요한 응용분야에 기존에 보유하고 있는 컴퓨팅 자원을 사용하여 구축될 수 있는 클러스터 시스템을 적용할 수 있다. 하지만 제공되는 서비스의 질을 예측하여 가용성과 성능 요구사항을 만족하기 위한 QoS 인지 클러스터 시스템 구조에 관한 연구가 필요하다. 따라서 본 논문에서는 차별화 된 서비스 제공과 의존도 요구사항을 만족하기 위해 다양한 메커니즘을 장착한 클러스터 시스템 구조를 도출하고 실제 상용 서비스를 제공하는 웹 서버의 로그 분석을 통한 작업 부하 모델링을 수행하여 얻은 시스템 운영 조건에 대한 성능 분석 실험을 수행하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.8B
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• pp.514-524
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• 2005

In optical burst switching(OBS) networks, the ingress edge router assembles packets in the same class queue into the appropriate size of burst. A burst control packet(BCP) is generated for channel reservation of corresponding data burst and sent earlier than the corresponding data burst with an offset time. Offset time is determined considering the number of hops from source to destination and the required quality of service(QoS). After offset time, the burst data is passed through tile pre-configured optical switches without any O/E/O conversion. But a failure in OBS networks may lead to the loss of bursts until the ingress nodes receive the failure indication signal. This results in a significant degradation in QoS. Therefore, in this paper, we propose a fault-tolerant node architecture based on sub-carrier multiplexing to reduce the effects of failure in OBS networks. The Performance of the proposed fault-tolerant node architecture exhibits considerable improvement as compared with the previous ones.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.1
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• pp.9-19
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• 1999

An increase of the number of the real time applications and the Internet hosts make the Internet architecture changed. Current Internet architecture has some problems to process the real time traffics. To solve these problem, a new Internet architecture is proposed as the Integrated Service model. In the current Internet, as multicast protocols, the QoS multicast and the best-effort multicast have been studied in their separate network environments. But, the Integrated Service Packet Network is a heterogeneous network composed of the QoS delivery domain and the best-effort delivery domain. Thus, those separated multicast protocols have limitations in an ISPN. In this paper, we propose a multicast protocol for the ISPN with the QoS and the best-effort multicasting, and analyze the performance of this protocol. As a result, we find that the packet losses are same for hybrid multicast and best-effort multicast when the bandwidth is sufficient. But, if there exist some background traffics, the hybrid multicast has less packet loss than of the best-effort multicast.

• Proceedings of the IEEK Conference
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• summer
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• pp.31-34
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• 2004

In an IP network, various types of traffics are statistically multiplexed to utilize efficiently the network resources. The DiffServ-aware-MPLS supports a wide variety of communication services with different QoS requirements. The DiffServ-aware-MPLS based on QoS architecture had become one of the most promising ways to guarantee QoS Multi-service IP network. But how to manage IP network with QoS guarantee is still an open issue. In this paper, we propose DiffServ-aware-MPLS buffer management technique using the specified policing, queuing, and scheduling

• Proceedings of the IEEK Conference
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• summer
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• pp.57-60
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• 2004

Next generation wireless network is evolving toward IP-based network that can various provide multimedia services. A challenge in wireless mobile Internet is support of quality of service over wireless access networks. DiffServ architecture is proposed for evolving wireless mobile Internet. In this paper we propose an algorithm for optimal buffer partitioning which requires the minimal channel capacity to satisfy the QoS requirements of input traffic. We used a partitioned buffer with size B to serve a layered traffic at each DiffServ router. We consider a traffic model with a single source generates traffic having J $(J\geq2)$ quality of service (QoS) classes. QoS in this case is described by loss probability $\varepsilon_j$. for QoS class j. Traffic is admitted or rejected based on the buffer occupancy and its service class. Traffic is generated by heterogeneous Markov-modulated fluid source (MMFS).

• ETRI Journal
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• v.30 no.2
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• pp.205-215
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• 2008

Many control schemes have been proposed for flow-level traffic control. However, flow-level traffic control is implemented only in limited areas such as traffic monitoring and traffic control at edge nodes. No clear solution for end-to-end architecture has been proposed. Scalability and the lack of a business model are major problems for deploying end-to-end flow-level control architecture. This paper introduces an end-to-end transport architecture and a scalable control mechanism to support the various flow-level QoS requests from applications.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.4 no.4
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• pp.380-386
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• 2003

As Internet is spreaded widely, the virtual communities among people with the same interest and hobby are dynamically created. The exchange of fruitful opinion and information makes them to be closed, not only with the help of the messaging system but also wireless terminals. The messaging system is a core technology supporting the global community services like chatting, messenger, short message services, and file sharing services. The paper focus on the design of software architecture for messaging system and the engineering model for QoS support.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.07a
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• pp.272-272
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• 2004