• Proceedings of the Korea Society for Simulation Conference
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• 2005.05a
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• pp.1-4
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• 2005

Information communication environment integrates communication, broadcasting and internet, and Digital Convergence service emerges in result. Thus, the effective routers are needed so that they can transmit a huge number of data to core internet through appropriate base center. Therefore, the network guaranteeing QoS in transport layer supports interoperability with different wireless networks. So as to users receive necessary information anywhere seamlessly, the network architecture focuses on packet transmission and it is efficient for the control layer switches and controls packets between different networks. Since individual users take advantage of different services and data, the effective router architecture must be designed. Hence in this paper we design monitoring technique to solve security problem and to support premium service to ultimate users. Thereafter, we run opnet simulation and show the improvement of proposed router architecture.

• Broadcasting and Media Magazine
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• v.20 no.1
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• pp.31-42
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• 2015

근래의 무선망 및 인터넷의 초고속화에 따라 다양한 멀티미디어 서비스가 활성화되고 있으며, 특히 방송 통신 융합망의 등장으로 인해 압축 부호화 기술만을 개발하던 시기와 달리 멀티미디어의 생성, 전송 및 소비 환경의 다양한 조건들에서 QoS(Quality of Service)를 보장하기 위해 비디오 부호화의 스케일러빌러티를 제공하기 위한 연구가 활발히 진행되고 있다. 본 고에서는 스케일러블 비디오 부호화의 개요에 대해 설명하고, 차세대 압축 표준인 HEVC(High Efficiency Video Coding)를 기반으로 시간적, 공간적, 화질적 스케일러빌러티를 제공하는 SHVC(Scalable HEVC)의 표준화와 이를 이용한 기술 개발 동향을 소개한다.

• Journal of Korea Multimedia Society
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• v.13 no.2
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• pp.279-286
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• 2010

Unbalanced traffic load offered to the nodes making up a path in the network guaranteeing quality-of-service has been known as a main cause deteriorating the capability of the path in admitting traffic flows. Several path load balancing methods have been developed to resolve this problem which used a feedback control scheme that adjusts the delay budget of a flow allocated to each node according to the conditions of available resource in the path. Because of no consideration about the probabilistic characteristics of the service quality, it is impossible for them to prevent in advance a bottleneck on the path which leads to a native restriction in the improvement of the capability being deteriorated. This paper proposes a preventive intra-path load balancing method applicable to the RSVP system which is based on the probabilistic characteristics of the quality-of-service of the offered load. The results of the simulation of the proposed method on a simple evaluation network showed that it provides the gain of 4~22% compared to the legacy one in terms of the number of admitted flows.

• Proceedings of the Korea Multimedia Society Conference
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• 2002.11b
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• pp.690-693
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• 2002

차세대 인터넷에서 DiffServ 네트워크는 서비스 품질(QoS: Quality of Service) 제공을 위한 확장성이 높은 구조를 제시하고 있다. 차세대 네트워크에서는 음성이나 비디오 전송 같은 많은 응용들을 지원하기 위하여 QoS 보장 서비스가 필요하다. 차세대 인터넷에서 QoS 제공을 위하여 RSVP(Resource Reservation Protocol), MPLS(Multi-Protocol Label Switching), DiffServ 및 QoS 라우팅 등의 기법이 개발되고 표준화되고 있다. 원격 교육 역시 주로 인터넷이 주도하고 있다는 면에서는 QoS의 문제를 피해 갈 수 없는 것이다. 그러나, 국내에서는 이러한 QoS 능력을 안전하게 제공하기 위한 기법에 대한 연구가 거의 없는 실정이다. 따라서, 본 논문에서는 QoS를 안전하게 제공하기 위한 보안 기법을 DiffServ 네트워크를 중심으로 제시하고 원격교육에 적용시의 문제들을 고려하고자 한다.

• Korean Management Science Review
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• v.16 no.1
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• pp.25-38
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• 1999

기존의 데이터망과는 달리 B-ISDN은 데이터, variable-rate 비디오 등과 같은 bursty하고 variable bit rate를 갖는 트래픽원으로부터 smooth하고 constant bit rate를 갖는 트래픽원까지 광범위한 계층의 트래픽을 모두 수용해야만 한다. 게다가 이 망은 다양한 계층의 트래픽에게 일정 수준 이상의 품질, 즉 QoS(Quality of Service)를 보장해 주어야만 한다. 셀 손실이나 지연시간 그리고 지연시간 jittere등을 포함하는 QoS 성능척도들은 응용서비스 별로 서로 다를 것이고 특히 실시간(real-time) 응용 서비스를 지원하는 망에서의 QoS문제는 특별히 중요성을 더하게 된다. 따라서 통계적 다중화에 의해 얻어지는 망자원의 효율성을 확보하면서 end-to-end QoS 보장을 해주는 문제는 B-ISDN에서 매우 중요하나 아직 대부분 미해결 문제로 남아 있는 분야이다. 본 연구에서는 end-to-end 분석에 가장 큰 에로점으로 부각되는 multi-hop망 환경하에서 트래픽 분석에 초점을 맞추어 기존 연구결과등을 폭넓게 비교 분석하고 최근 연구 동향 및 추후 연구 사항을 제시하고자 한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.7
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• pp.4878-4883
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• 2015

The IP Multimedia Subsystem(IMS) is a framework that provides access to the content of Internet and Telecom services anytime and anywhere with guaranteed Quality of Service(QoS) and manageability by separating control functions from bearer and services. The Service Delivery Platform(SDP) provides common interfaces and protocols to deploy existing or new services in an efficient way. Therefore SDP over IMS plays a role of bridge between established network and new IMS network by simplifying the interaction among application services. In order to enrich the multimedia network communication, we try to deploy the Push-to-talk over Cellular(PoC) service which is considered as the outstanding and distinguished half-duplex Voice over IP(VoIP) application service among deployable candidate services over mobile network. In this paper we investigate the advantages of PoC service and PoC architecture firstly, and then focus on the its practical implementation for the prototype to validate the feasibility of its deployment and realization.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.9C
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• pp.836-841
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• 2002

Packet scheduling is an essential function to guarantee a quality of service by differentiating services in the Internet. Scheduling algorithms that have been suggested so far can be devided into Round-Robin methods and Fair Queueing methods Round-Robin methods have the advantage of high-speed processing through simple implementations, while Fair Queueing methods offer accurate services. Fair queueing algorithms, however, have problems of computational overheads and implementation complexity as their schedulers manage the states of every flow. This paper suggests a new method in which each flow performs the calculation in a distributed way to decide the service order. Our algorithm significantly reduces the scheduler's computational overheads while providing the same level of accuracy with the previous Fair Queueing algorithms.

• Journal of Internet Computing and Services
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• v.10 no.2
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• pp.161-169
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• 2009

The development of Wireless Multimedia Sensor Networks(WMSNs) is getting realized in accordance with the increased demands to provide multimedia data transmission service such as CCTV movie, image chapter information, audio information based on wireless sensor network. It is very important to provide the differentiated quality assurance of service. In this paper, we propose a sensor medium access control protocol based on DSMAC, which provides differentiated Quality of Service(QoS) for delay. A proposed protocol is able to reduce the delay without increasing the energy consumption by adaptively changing the duty cycle according to the buffer occupancy. Simulation results show that the new MAC protocol performs better in terms of latency than S-MAC and DSMAC.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.5C
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• pp.435-444
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• 2002

In this paper, a novel packet scheduling algorithm, so-called the CSL algorithm is discussed, whereby the firewall property as well as the deterministic delay bound guarantee are supported in session level. Lots of simulation studies validate those properties of the CSL algorithm. The CSL algorithm is distingushable from the well- known EDD scheme in terms of the firewall property. Regarding the implementation complexity, the CSL algorithm turns out to be of 0(1) besides the sorting overhead. Owing to the maintained generic fair queueing structure in the CSL algorithm, a various fair queueing schemes can be applied with minor modification. For the TCP/IP network which is vulnerable to the misbehaving traffic sources, the firewall property of the CSL algorithm is quite useful for the advanced quality of services.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.6
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• pp.1177-1186
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• 2003

The multimedia ad hoc wireless network is quite an attractive issue since it offers a flexible solution to enable delivery of multimedia services to mobile end users without fixed backbone networks. However, with the unique design challenges of ad hoc wireless networks, it is a non-trivial issue to provide bounded delay guarantee, with fair share of resources. In this paper, we implemented the delay guaranteed fair queueing (DGFQ) scheme distributively. Through the results of performance evaluation, we can conclude that DGFQ also performs well to control bounded delay in multimedia ad hoc wireless networks.