• 한국멀티미디어학회논문지
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• 제11권1호
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• pp.44-52
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• 2008

본 논문은 Grade Of Services Steiner Minimum Tree 문제 해결을 위한 우리의 휴리스틱의 개선에 관한 것이다. 이 문제는 멀티미디어 통신에서 응용할 수 있는 여러 등급의 서비스를 각기 제공할 수 있는 네트워크를 설계하는데 적용할 수 있다. NP-Hard 문제로 알려진 이 문제는 주어진 터미널 노드를 모두 연결하고 G-Condition을 만족하는 네트워크 중에서 가장 적은 구축비용을 만족하는 네트워크를 찾는 것이다. 우리의 이전 연구에서 이 문제를 해결하기 위한 몇 개의 휴리스틱을 제안했다. 본 논문에서는 이 휴리스틱의 성능을 개선하기 위해 G-Condition 검사 순서 및 방법에 대한 전략을 제안한다. 이 전략을 반영한 개선된 휴리스틱들에 관한 실험은 이전 것들에 비해 평균적으로 실행시간은 71.9%, 스타이너 포인트의 수는 28.9%, 네트워크 구축비용은 1.1%의 감소의 결과를 얻었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.86-88
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• 2004

As the rapid incensement of the number of internet users has occurred recently, many multimedia application services have been emerging. To improve quality of service, traffic can be suggested to be classified with priority in EPON(Ethernet Passive Optical Network), which is supporting the multimedia application services. In this paper, multimedia application services treat bandwidth classifying device in serving both delay sensitive traffic for real-time audio, video and voice data such as VoIP(Voice over Internet Protocol), and nonreal-time traffic such as BE(Best Effort). With looking through existing mechanisms, new mechanism to improve the quality will be suggested. The delay performances and packet losses of traffic achieved by supporting bandwidth allocation of upstream traffic in suggested mechanism will be analyzed with simulation.

• Journal of Information Processing Systems
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• 제6권3호
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• pp.359-374
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• 2010

The Future Internet that includes Real World Objects and the Internet of Things together with the more classic web pages will move communications from a nodecentric organization to an information-centric network allowing new a paradigm to take place. The 4WARD project initiated some works on the Future Internet. One of them is the creation of a Network of Information designed to enable more powerful semantic searches. In this paper, we propose a security solution for a model of information based on a semantic description and search of objects. The proposed solution takes into account both the access and the management of both objects and their descriptions.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 신호처리소사이어티 추계학술대회 논문집
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• pp.255-258
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• 2003

TCP is taking over 95％ among the Internet traffics. Recently the demands of multimedia services in the Internet has been increasing. These multimedia services mostly need real-time deliverly, and then RTP has been a de facto to transmission protocol for these real-time multimedia services. RTP uses UDP as its underlying transport protocol, and thus it does not support any rate and congestion control. Thus, for fair use of the Internet bandwidth with TCP traffics. RTP also needs a rate control. One constraint of RTP is that the feedback information(delivered by, RTP's twin protocol, RTCP) is recommended to be sent no less than 5 seconds. In this paper, we propose a TCP-friendly RTP rate control which use only RTCP feedback information at every 5 seconds. The experiment results show that our proposed algorithm works. But, it is found that we need more time to test the effects of parameters and policies of the algorithms, which will be reported later.

• 전기전자학회논문지
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• 제4권2호
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• pp.281-287
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• 2000

A mobile ad-hoc network is composed of only mobile nodes, which are distributed dynamically, without any wired backbone or centralized entities. Since the existing works on ad-hoc routing protocol are mostly biased toward a military application, we need a new routing scheme for a support of multimedia services in mobile ad-hoc networks. Therefore, we propose a novel scheme that can support a variety of traffic attributes and can be applicable to high-speed and multimedia data services in mobile ad-hoc networks by using adaptive transmission power level. As a result of simulation, the proposed scheme has better performance than conventional method, which is performed with uniform transmission power level, in view of route query delay time.

• 한국콘텐츠학회논문지
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• 제6권2호
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• pp.9-16
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• 2006

본 논문은 광대역 무선 통신망의 물리계층 OFDMA시스템 구조에서 멀티미디어 패킷 서비스의 효율적인 처리를 위한 스케줄링 알고리즘을 제안한다. 스케줄링 알고리즘은 무선 채널 상태 정보 추정을 이용하고 클래스 및 우선권 정책 기반 전송 순위 결정과 이에 의한 전송률 할당을 한다. 그 결과로 제안된 스케줄링 알고리즘은 실시간 서비스에 대해선 최대 트래픽 처리량과 jitter의 최소화를 만족하고 비실시간 서비스에 대해 공평한 트래픽 처리를 수행한다. 제안 된 스케줄링 알고리즘은 기존의 라운드 로빈 스케줄링 방식과 시뮬레이션을 통한 비교를 통해서 보다 우수한 성능을 보인다.

• 한국멀티미디어학회논문지
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• 제20권7호
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• pp.1030-1037
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• 2017

Traffic flows of real-time multimedia services such as Internet phone and IPTV are bounded on the end-to-end delay. Packets violating their delay limits will be dropped at a router because of not useful anymore. Service providers promise the quality of their providing services in terms of SLA(Service Level Agreement), and they, especially, have to guarantee the packet loss rates listed in the SLA. This paper is about a method to guarantee the required packet loss rate of each traffic flow keeping the high network resource utilization as well. In details, it assures the required loss rate by adjusting adaptively the timestamps of packets of the flow according to the difference between the required and measured loss rates in the lossy Weighted Fair Queuing(WFQ) scheduler. The proposed method is expected to be highly applicable because of assuring the packet loss rates regardless of the fluctuations of offered traffic load in terms of quality of services and statistical characteristics.

• 한국통신학회논문지
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• 제23권9A호
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• pp.2249-2257
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• 1998

In this paper, we propose the enhanced priority control algorithm that adaptively controls the cell service ratio according to the relative cell occupancy ratio of buffer. The asynchronous transfer mode (ATM) provides the means to support various multimedia services in broadband networks. To support multimedia services, various data traffics of different priorities should be controlled effectively. And also it needs congestion control functions required in the netowrk to carry out the control operation. To accomplish this in a flexible and effective manner, priority classes for the different services ar ecommonly used. The proposed enhanced priority control mechanism have two service calsses of the delay sensitive class and the loss sensitive class. The simulation results show that te proposed control mechanism improves the QoS, the charateristics of cell loss probability and mean cell delay time, by selecting propeor relativ ecell occupancy ratio of buffer and the average arrival rate.

• 대한의용생체공학회:의공학회지
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• 제17권1호
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• pp.33-42
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• 1996

A multimedia remote ultrasound image transfer system for tole-medical services was implemented. The image data of the ultrasound scanner system of the slave is compressed using image compression system. It is transferred to the master PC via ISDN UNI(User-Network Interface) and decompressd by image decompression system. The total system is composed of three parts; first, the image capture card which transfers bidirection- al data between ultrasound scanner system and PC, second, image compression and decompression card, finally, ISDN TA(Terminal Adaptor) card for transferring the image. This system has a easy user interface because it is executed on the basis of MS-WINDOWS. So it is capable of serving medical services at a remote place.

• Journal of Communications and Networks
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• 제8권3호
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• pp.297-305
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• 2006

High-rate wireless personal area network (HR-WPAN) has been standardized by the IEEE 802.15.3 task group (TG). To support multimedia services, the IEEE 802.15.3 TG adopts a time-slotted medium access control (MAC) protocol controlled by a central device. In the time division multiple access (TDMA)-based wireless packet networks, the packet scheduling algorithm plays a key role in quality of service (QoS) provisioning for multimedia services. In this paper, we propose an adaptive cross-layer packet scheduling method for the TDMA-based HR-WPAN. Physical channel conditions, MAC protocol, link layer status, random traffic arrival, and QoS requirement are taken into consideration by the proposed packet scheduling method. Performance evaluations are carried out through extensive simulations and significant performance enhancements are observed. Furthermore, the performance of the proposed scheme remains stable regardless of the variable system parameters such as the number of devices (DEVs) and delay bound.