• ETRI Journal
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• 제30권2호
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• pp.216-226
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• 2008

This paper proposes a novel transport network architecture for the next generation network (NGN) based on the optical burst switching technology. The proposed architecture aims to provide efficient delivery of various types of network traffic by satisfying their quality-of-service constraints. To this end, we have developed a soft-state bandwidth reservation mechanism, which enables NGN transport nodes to dynamically reserve bandwidth needed for active data burst flows. The performance of the proposed mechanism is evaluated by means of numerical analysis and NS2 simulation. Our results show that the packet delay is kept within the constraint for each traffic flow and the burst loss rate is remarkably improved.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권4호
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• pp.784-799
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• 2013

This paper presents an adaptive rate control scheme for streaming-based content sharing service. This scheme delivers multimedia contents from a user device to another device or seamlessly redirects streaming service across heterogeneous user devices. In the proposed scheme, a streaming server adjusts video quality level according to the network and client status. Our scheme is different from other rate control schemes, because the video quality at the server is decided not only based on the available bandwidth, but also based on the device characteristics and bandwidth requirement at the access network. We also propose a bandwidth estimation method to achieve more equitable bandwidth allocations among streaming flows competing for the same narrow link with different Round Trip Times (RTTs). Through the simulation, we prove that our scheme improves the network stability and the quality of streaming service by appropriately adjusting the quality of the video stream. The simulation results also demonstrate the ability of the proposed scheme in ensuring RTT-fairness while remaining throughput efficient.

• Journal of information and communication convergence engineering
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• 제3권3호
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• pp.123-130
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• 2005

This study performed five methods of tests and measurements to verify the improvement of connection time and bandwidth efficient of FSS (fixed satellite service) TCP/IP network by means of the cash function and the spoofing function. Tests and measurements are performed with; 1. Not to apply the cash and spoofing function 2. Apply the cash function 4. Apply both cash and spoofing function in HUB station and VSAT 5. In a typical commercial terrestrial Internet with LAN. The study results in this paper show that application of the spoofing and cash function greatly improves the bandwidth efficiency to FSS TCP/IP Internet service.

• 산업기술연구
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• 제24권B호
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• pp.177-186
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• 2004

The main bottleneck for a VOD system is bandwidth of storage or network I/O due to the high bandwidth requirements and long-lived nature of digital video. Patching is one of the most efficient techniques to overcome the bottleneck of the VOD system through the use of multicast scheme. In this paper, we propose a new patching scheme, P2P proxy patching, for improving the typical patching technique by jointly using the proxy prefix caching scheme and the P2P proxy. In our proposed scheme, each client play a role in a proxy for multicasting a regular stream to other clients that request the same stream. Due the use of the P2P proxy and the prefix caching, the server bandwidth is required significantly less than that of the typical patching technique. In the performance study, we show that our patching scheme can reduce the server bandwidth requirements compared with the existing patching techniques.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2013년도 춘계학술대회
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• pp.747-748
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• 2013

본 논문에서는 XGPON1 (10-Gbps-capable passive optical network stage 1) 시스템에 사용 가능한 새로운 동적 polling 방법을 제안한다. XGPON1 시스템은 상향 2.5 Gbps, 하향 10 Gbps 속도를 지원한다. XGPON1 시스템에서는 polling 빈도가 높으면 동적대역할당의 효율이 증가하지만 상향대역폭이 낭비되는 문제가 발생된다. 제안된 polling 방법은 polling에 사용되는 상향 대역폭 낭비를 줄이고 동시에 polling 횟수를 효율적으로 향상시킨다.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 2002년도 춘계공동학술대회
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• pp.402-408
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• 2002

Multicast technology allows the transmission of data from one source node to a selected group of destination nodes. Multicast routes typically use trees, called multicast routing trees, to minimize resource usage such as cost and bandwidth by sharing links. Moreover, the quality of service (QoS) is satisfied by distributing data along a path haying no more than a given number of arcs between the root node of a session and a terminal node of it in the routing tree. Thus, a multicast routing tree for a session can be represented as a hop constrained Steiner tree. In this paper, we consider the hop-constrained multicast route packing problem with bandwidth reservation. Given a set of multicast sessions, each of which has a hop limit constraint and a required bandwidth, the problem is to determine a set of multicast routing trees in an arc-capacitated network to minimize cost. We propose an integer programming formulation of the problem and an algorithm to solve it. An efficient column generation technique to solve the linear programming relaxation is proposed, and a modified cover inequality is used to strengthen the integer programming formulation.

• ETRI Journal
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• 제27권6호
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• pp.802-805
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• 2005

A dynamic bandwidth allocation (DBA) scheme, an inter -optical network unit (ONU) bandwidth scheduling, is presented to provide quality of service (QoS) to different classes of packets in Ethernet passive optical networks (EPONs). This scheme, referred to as TADBA, is based on efficient threshold reporting from, and adaptive polling order rearranging of, ONUs. It has been shown that the network resources are efficiently allocated among the three traffic classes by guaranteeing the requested QoS, adaptively rearranging the polling orders, and avoiding nearly all fragmentation losses. Simulation results using an OPNET network simulator show that TADBA performs well in comparison to the available allocation scheme for the given parameters, such as packet delay and channel utilization.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2018년도 추계학술대회
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• pp.431-433
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• 2018

본 논문은 광대역 음성의 음질 향상을 위해 시간 영역에서 인공대역 확장 기술을 사용하여 초광대역 음성신호를 출력하여 사용자에게 개선된 음질의 음성을 제공하는 시스템을 제안한다. 시간 영역에서 소스필터 모델에 기반하여 광대역 여기신호 및 LSP를 추출하고, 각각의 대역폭 확장 알고리즘을 적용였고, 초광대역 여기신호 및 LSP를 추론하여 초광대역 음성신호를 합성한다. 주관적인 테스트를 통해 광대역 음성신호보다 초광대역 음성신호의 음질을 더 선호하는 결과를 도출하였다.

• 한국정보과학회논문지:정보통신
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• 제37권6호
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• pp.415-419
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• 2010

본 논문에서는 이동 셀룰러 네트워크 환경에서 한정된 자원인 무선대역폭을 효율적으로 사용하기 위해 게임이론을 이용한 대역폭 예약 기법을 제안하였다. 제안된 기법에서는 게임 이론의 협상 해법 중 대표적인 NBS 기법을 이용하여 전체 시스템의 효용을 극대화하는 최적의 대역폭 대여량과 예약량을 계산한다. 성능평가 결과 제안된 기법이 다양한 네트워크의 상황에 탄력적으로 대응할 수 있었기에 기존에 제안된 기법에 비해 뛰어난 성능을 보임을 확인할 수 있었다.

• 한국멀티미디어학회논문지
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• 제7권8호
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• pp.1078-1085
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• 2004

SARLM(Source Adaptive Receiver-Driven Multi-Layered Multicast)은 레이어 병합과 분할을 통해 수신자의 이질적인 대역폭 문제를 개선하고자 하였다. 그러나 이 기법은 레이어 병합 시에 상위 레이어의 수신자가 하위 레이어로 드롭되어 가용 대역폭의 이용률이 저하되는 문제가 있다. 본 논문에서는 수신자의 손실률 정도를 고려한 멀티캐스트 재그룹 기법을 제안한다. 제안 기법은 손실률에 따라 가중치를 부여하여, 상위 레이어와 하위 레이어 중 여유 대역폭이 많은 수신자를 그룹화하고, 하위 레이어와 상위 레이어 중 손실률이 높은 수신자를 그룹화한다. 실험 결과, 상위 레이어 수신자가 높은 전송률을 유지함으로써 수신자의 가용 대역폭 이용률이 향상됨을 알 수 있다.