• 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.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.4
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• pp.31-41
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• 2009

IEEE 802.11e proposed by IEEE 802.11 working group to guarantee QoS has contention based EDCA and contention free based HCCA. HCCA, a centralized polling based mechanism of 802.11e, needs a scheduling algorithm to allocate the network resource efficiently. The existing standard scheduler, however, is inefficient to support for QoS guarantee for real-time service having VBR traffic. To improve these limit, in this paper, we First, we propose priority polling algorithm which additionally considers the size of MSI and TXOP based on EDD algorithm to increase number of QSTAs. We also propose a dual token bucket TXOP allocation algorithm to reduce congestion caused by stations which enters network with considerable delay variance. TSPEC parameters, Maximum Burst Size (MBS) and Peak Data Rate (PR), are applied to design depth and token generation rate of two buckets. Simulation results show that the proposed algorithm has much higher performance compared with reference and SETT-EDD scheduler in terms of throughput and delay.

• Journal of Digital Contents Society
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• v.14 no.4
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• pp.429-437
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• 2013

Recently, wireless mesh network has been focused as a core technology for resolving the issues of shadow zone and distributed bypass route as it has broad service coverage as well as good scalability features. It, however, provides users with relatively lower QoS than infrastructure-based networks. In order for addressing this QoS issue and also enhancing the routing performance of mobile WiMax mesh network, this paper proposes a load sensing QoS routing (LSQR) scheme. In the proposed LSQR, each node figures out network congestion status and selects a bypass route accordingly. With this scheme, we can expect good load balancing effect by changing the routing paths from centralized links to distributed links under a heavy traffic condition. From the simulation results using NS-2, it has been verified that the LSQR shows lower packet loss rates and data transmission delays than the existing representative routing schemes.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.2
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• pp.455-461
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• 2008

Enhanced Distributed Channel Access (EDCA) is a channel access scheme adopted by the IEEE 802.11e draft standard for QoS-enabled wireless local area networks. It classifies traffic into separate Access Categories (ACs) and achieves service differentiation by allowing each AC to have its own values of channel access parameters. This paper proposes a scheme to dynamically adapt the EDCA parameters to traffic environment so that they both maximize the throughput of non real-time traffics and meet the delay and throughput constraints of real-time traffics. For this purpose, we develop a design algorithm for efficient exploration of the EDCA parameter space. Using the algorithm, we derive a Pareto curve fur delay-throughput trade-off in each anticipated traffic environment. The Pareto database can then be used to optimally adjust the parameter according to the traffic environment and administrative policies. Simulation results show that compared with the default parameter configuration, the proposed scheme is better for delay, throughput guarantee and can improve the throughput of non real-time traffics by 12% on average.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.5B
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• pp.430-441
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• 2006

As the various A/V devices and home networks are delivered to users, home networks are changing to an entertainment network. It is expected that the required network bandwidth and the amount of usage of media content in home entertainment networks will be increased. Although the access networks and home networks becoming a high speed network, there remains the problems for QoS-guaranteed media content transfer in home networks. Also, in the home network, there can be network traffic caused by applications like video conferencing, video telephone, and VoIP(voice over IP) as well as inner network traffic of home network. Since media content transfer requires the real-time delivery, it is very important and basic requirement that is to transfer media content to A/V device user wants while keeping the media quality. Even though there are many middleware protocol for home networking, they provide basic device discovery and control or simple functions for QoS-guaranteed media content transfer that are not enough to provide QoS-guaranteed media transfer service that user wants. Thus, in this paper, we propose the technique based on UPnP(universal plug and play) protocol for QoS-guaranteed media content transfer in the home network. The proposed technique is compatible with UPnP and can be used with UPnP as additional functions. In this paper, we utilize VideoLAN application to verify the proposed technique. We add the additional modules that support the proposed technique's function to VideoLAN and we verify the its functions through various test scenarios.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04a
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• pp.595-597
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• 2004

인터넷 트래픽 관리(ITM： Internet Traffic Management)는 네트워크의 물리적인 속도의 한계를 논리적인 기술을 적용해 극복하고자 하는 목적을 가지고 있다. 멀티미디어 서비스 수요의 증가와 서비스 품질(QoS) 보장을 위해서 효율적인 콘텐츠 라우팅 설계는 매우 중요하다. 콘텐츠 라우팅 기술의 핵심 기능은 서비스 사용자에게 최적의 경로를 선정해 서비스 속도 향상과 콘텐츠 제공자에게는 콘텐츠를 분산 장애가 발생시 서비스의 우회에 있다. 본 논문에서는 웹 서비스를 지원하는 XML 기반의 복수의 능동 에이전트를 이용해서 효율적인 트래픽 관리를 제공함으로써 QoS를 보장하는 설계를 제안한다.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04a
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• pp.637-639
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• 2004

GFR 서비스는 ATM 네트워크에서 인터넷 트래픽을 효과적으로 처리하기 위하여 ATM 포럼에서 정의되었다. 단순 FIFO 기반 GFR 구현 기법은 가상 연결 단위의 계수기나 분리된 버퍼 관리가 필요치 않아 실용적이지만, QoS가 만족스럽지 않다. 본 논문은 이 구현 기법의 QoS를 개선할 수 있는 방안을 찾기 위해, 이 구현 기법의 문제점을 명확히 하고자 컴퓨터 시뮬레이션을 수행하고 그 결과를 분석하였다. TCP 트래픽에 따른 성능 평가를 위해 Tahoe와 New-Reno 두 버전을 각각 적응하였다.

• Journal of Korea Multimedia Society
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• v.16 no.3
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• pp.290-301
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• 2013

The hospital network requires the effective transmission of multimedia PCAS data for medical treatment. But the network traffic has happened frequently in consultation hours because of the limited resources of hospital network and high capacity of PACS data. This is major interruption for the medical treatment. This problem can be solved by the adaptive QoS. In this paper, we design the middleware based QoS architecture in hospital network for controlling the contribution system. Our virtual simulation verifies that our middleware assures QoS of the priority PACS data of audio and image compared with the conventional hospital network.

• Proceedings of the Korea Multimedia Society Conference
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• 2001.06a
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• pp.223-227
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• 2001

인터넷의 발전에 따라 서비스에 대한 사용자 요구가 다양해지는 동시에 서비스 품질에 대한 요구가 높아지고 있다. 멀티미디어 서비스는 대량의 데이터로 구성되어 네트워크에 트래픽 부하를 증가시키며 이로 인한 지연, 동기, 패킷 손실과 칼은 문제가 발생되나 서비스의 품질을 협상할 수 있다는 특성도 가지고 있다. 이 연구에서는 인터넷에서 제한된 대역폭의 사용 효율성을 높이면서 멀티미디어 서비스의 품질(QoS)을 보장하기 위한 기법으로 동기화된 멀티미디어 서비스의 QoS와 통계에 기반을 둔 지수적 무게 이동 평균 기법을 제안하였고, 협상을 위한 모듈을 설계하였다.

• Journal of Korea Multimedia Society
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• v.7 no.3
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• pp.399-407
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• 2004

As the number of IP-users are increasing, it is getting so important for service providers to check the state of the current Internet and their service quality by measuring the traffic quality. We describe a general concept of measurement architecture and internet QoS (Quality of Service) parameters, and we review measurement tools. To meet these requirements, we design and implement the Internet traffic management system.