• Proceedings of the Korean Information Science Society Conference
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• 2012.06d
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• pp.404-406
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• 2012

최근 네트워크 기술의 발달과 모바일 기기 성능의 향상으로 대화형 멀티미디어 서비스에 대한 요구가 증가하고 있다. 대화형 멀티미디어 서비스는 음성과 영상을 실시간으로 주고받는 서비스로 지연에 민감한 특성을 가진다. 따라서 대화형 멀티미디어 서비스의 품질을 보장하기 위해서는 재생 지연한계를 고려해야 한다. 본 논문에서는 대화형 멀티미디어 서비스의 단대단 지연한계를 보장하기 위해서 네트워크와 송신버퍼 그리고 수신버퍼에서 발생하는 지연을 고려하여 전송률을 조절하는 기법을 제안한다. 제안하는 기법은 송신버퍼와 수신버퍼에 지연한계를 설정하고 이를 보장하기 위해 전송률을 조절함으로써 지연한계와 재생의 연속성을 보장하였다. 실험을 통해 본 논문이 대화형 멀티미디어 서비스의 단대단 지연한계를 보장함을 보였다.

• Journal of KIISE:Information Networking
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• v.37 no.6
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• pp.483-488
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• 2010

Due to the prevalence of various mobile devices and wireless broadband networks, there has been a significant increase in interest and demand for multimedia streaming services. Moreover, the user can service the participatory video broadcasting service in the mobile device and it can be used to deliver the real-time news and more variety information in the user side. Live multimedia service of user participation should consider not only the video quality but also the delay bounds and continuity of video playback for improving the user perceived QoS (Quality of Service) of streaming service. In this paper, we propose an adaptive rate control scheme, called DeBuG (Delay Bounds Guaranteed), to guarantee the delay bounds and continuity of video playback for the real-time streaming in mobile devices. In order to provide those, the proposed scheme has a quality adaptation function based on the transmission buffer status and network status awareness. It also has a selective frame dropper, which is based on the media priority, before the transmission video frames. The simulation results demonstrate the effectiveness of our proposed scheme.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.6A
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• pp.1008-1018
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• 2001

본 논문에서는, 트래픽으로부터 요구된 지연한계를 보장하는 스케줄링 알고리즘으로서, \"클래스별 서비스 차등제공\" 알고리즘을 제안하였다. 제안된 알고리즘은, 공평 큐잉과 우선순위 제어 개념의 절충형 패킷 스케줄링 알고리즘이다. 다수의 트래픽 클래스 환경에서, 각 클래스별 서비스 커브를 정의하며, 클래스별 지연 한계를 충족시키기 위한 각 서비스 커브의 형태, 그리고 서비스 커브간의 관계에 근거하여, 클래스별 차등 서비스를 제공한다. 또한, 동일한 클래스 내의 세션간에는 공평 큐잉을 제공함으로써, 세션별 최소한의 대역폭이 보장될 수 있도록 한다. 지연 제어를 위해 새로 정의된 변수는, 시스템 상태에 따라 그 값이 조정됨으로써, 자원의 효율적 활용을 가능하게 한다. 제안된 알고리즘은 가상적 fluid-flow 모델에서 디자인되었으며, 이를 실질적인 패킷 모드에서 구현하는 방안이 제시되었다. 아울러, 제안된 스케줄링 알고리즘에 수반되는, 결정적 형태의 지연 보장을 위한 호 수락 제어조건을 유도함으로써, 수용된 세션들의 지연 성능이 확정적으로 보장될 수 있도록 하였다.수 있도록 하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.7
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• pp.1618-1626
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• 2013

Virtualization service processes all operation including the data creation, storing, and disposal in a server and transmits processed data as the streaming media form. Therefore, client can use the same environment as the traditional desktop environment without considering the type of device. Virtualization service should consider not only the video quality but also the delay bounds and continuity of video playback for improving the user perceived Quality of Service(QoS) of streaming service. In this paper, we propose a network-adaptive transmission architecture that focuses on guaranteeing QoS requirements for virtualization service. In order to provide those, the proposed architecture have the transmission rate adaptation function based on available bandwidth and the content bit-rate control function based on sender buffer state. Through each function, proposed architecture guarantee the delay bounds and continuity of virtualization contents playback. The simulation results show that proposed network-adaptive transmission architecture provides a improve performance of throughput and transmission delay.

• Journal of KIISE:Information Networking
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• v.30 no.5
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• pp.641-648
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• 2003

In this paper, we propose a general analysis tool that derives guaranteed delay bounds for real-time sessions when those sessions pass through heterogeneous schedulers in general packet networks. This tool characterizes each different scheduler by a homogeneous service curve server. We show that service curve servers can characterize a strictly larger class of schedulers than LR servers. That is, we can characterize not only all LR servers but also RC-EDF and SC scheduler by service curve servers. Even with such advantage over LR servers, service curve servers provide accurate analysis results. We prove mathematically that if we analyze a network that can be analyzed by both LR servers and service curve servers,,both cases yield the same delay bound.

• Proceedings of the Korean Information Science Society Conference
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• 2010.06a
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• pp.218-219
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• 2010

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.2
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• pp.236-247
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• 2002

We propose a cell－multiplexing scheme for the real－time communication service in ATM network and a new service discipline guarantee end-to-end delay based on pseudo-isochronous cell switching. The proposed scheme consists of two level frame hierarchy, upper and lower frame, which is used to assign the bandwidth and to guarantee the requested delay bound, respectively. Since the Proposed algorithm employs two level frame hierarchy, it can overcome the coupling problem which is inherent to the framing strategy It can be comparatively reduce the complexity, and still guarantee the diverse delay bounds of end-to-end. Besides, it consists of two components, traffic controller and scheduller, as the imput traffic description model and regulates the input traffic specification. The function of the traffic controller is to shape real -time traffic to have the same input pattern at every switch along the path. The end-to-end delay is bounded by the scheduller which can limit the delay variation without using per-session jitter controllers, and therefore it can decrease the required buffer size. The proposed algorithm can support the QoS's of non-real time traffic as well as those of real time traffic.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10e
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• pp.649-651
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• 2002

이동 컴퓨팅 환경에서 양질의 멀티미디어 서비스를 제공하기 위해서는 트래픽에 대한 QoS가 보장되어야 한다. 그러나 기존의 자원 예약 기법은 유선 네트워크를 위해 설계된 것이므로 무선 이동 네트워크에서의 QoS 보장 문제를 상당부분 해결하지 못하고 있는 실정이다. 또한 최근에는 마이크로 셀들로 구성된 네트워크가 증가함에 따라 빈번한 핸드오프로 인한 전송지연 문제와 이동호스트(MN: Mobile Node)의 위치 이동을 신속하게 제어해야 하는 문제 등이 발생하고 있다. 따라서 이러한 마이크로 셀룰러 환경에서는 기존의 Mobile IP와 RSVP 연동기법을 사용하는 것만으로는 한계가 있다. 본 논문에서는 마이크로 셀룰러 네트워크에서 QoS를 보장하기 위해 CRSVP(Cellular RSVP Protocol)라는 새로운 프로토콜을 제안한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.5C
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• pp.445-453
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• 2002

We propose a cell-multiplexing scheme for the real-time communication service in ATM network and a new service discipline guarantee end-to-end delay based on pseudo-isochronous cell switching. The proposed scheme consists of two level frame hierarchy, upper and lower frame, which is used to assign the bandwidth and to guarantee the requested delay bound, respectively. Since the proposed algorithm employs two level frame hierarchy, it can overcome the coupling problem which is inherent to the framing strategy. The proposed scheme consists of two components, traffic controller and scheduller, as the imput traffic description model and regulates the input traffic specification. The function of the traffic controller is to shape real-time traffic to have the same input pattern at every switch along the path. The end-to-end delay is bounded by the scheduller which can limit the delay variation without using per-session jitter controllers, and therefore it can decrease the required buffer size. The proposed algorithm can support the QoS's of non-real time traffic as well as those of real time traffic

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.8A
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• pp.1134-1143
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• 2000

We propose a scheduling algorithm, Bandwidth Allocation Scheme (BAS), that guarantees bounded delay in a switching node. It is based on the notion of the GPS (Generalized Processor Sharing) mechanism, which has clarified the concept of fair queueing with a fluid-flow hypothesis of traffic modeling. The main objective of this paper is to determine the session-level weights that define the GPS sewer. The way of introducing and derivation of the so-called system equation' implies the approach we take. With multiple classes of traffic, we define a set of service curves:one for each class. Constrained to the required profiles of individual service curves for delay satisfaction, the sets of weights are determined as a function of both the delay requirements and the traffic parameters. The schedulability test conditions, which are necessary to implement the call admission control, are also derived to ensure the proposed bandwidth allocation scheme' be able to support delay guarantees for all accepted classes of traffic. It is noticeable that the values of weights are tunable rather than fixed in accordance with the varying system status. This feature of adaptability is beneficial towards the enhanced efficiency of bandwidth sharing.