• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.11a
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• pp.481-481
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• 2004

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.11a
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• pp.7-7
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• 2004

• Proceedings of the IEEK Conference
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• summer
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• pp.395-399
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• 2004

We present modality conversion as an effective means for QoS management. We show that modality conversion, in combination with content scaling, would give a wider range of adaptation to support QoS at media level. Here, we consider modality conversion with respect to resource constraint and human factor. To represent modality conversion as well as content scaling, we present the overlapped content value (OCV) model that relates the content value of different modalities with resources. The specification of user preference on modality conversion is divided into qualitative and quantitative levels. The user preference is then integrated into the OCV model so that modality conversion correctly reflects the user's wishes. For the conversion of multiple contents, an optimization problem is formulated and solved by dynamic programming. The experiments show that the proposed approach is efficient to be applied in practice.

• Journal of the Korean Operations Research and Management Science Society
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• v.28 no.3
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• pp.169-184
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• 2003

In the IS-95 packet service system, the radio channels are generally classified into the dedicated and the common traffic channels. In this paper, a common traffic channel access method is proposed for the COMA packet service system to enhance the radio resource utilization while guaranteeing QoS to the users. The proposed method is based on the permission probability for the common traffic channel user. To derive permission probability, optimization models are developed for two different QoS constraints. Approximation methods are also developed.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2006.05a
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• pp.1055-1059
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• 2006

가입자망의 구현 형태의 하나인 EPON(Ethernet Passive Optical Network)에서의 대역할당 방식을 다룬다. EPON의 서비스 성능은 상향 트래픽을 어떻게 처리해주는 가에 영향을 많이 받는데, 본 논문에서는 4가지 등급으로 구분된 서비스 트래픽에 대한 QoS(Quality of Service)를 고려한 데이터 전송 서비스를 위한 알고리즘을 하나 제시하고, 이에 대한 성능 분석을 위해 시뮬레이션을 한다.

• The KIPS Transactions:PartC
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• v.15C no.6
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• pp.557-566
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• 2008

NGN(Next Generation Network) is a communication network which can make use of broadband and QoS-enabled transport technologies. One of the main service issues over NGN is a multimedia service, such as IPTV, using a multicast method. And overlay multicast technology is one of the promising solutions instead of traditional multicast technology which has a few problems, and supports flexibility and scalability for multicast services. Also, the main controversial topic in NGN and overlay multicast is QoS. In the present paper, we designed an agent in each receiver's network, and a manager which is in a source network and which manages the whole multicast network. Both of them are communicating with each other and applying resource policies to their multicast network. This mechanism enables overlay multicast to support QoS, focusing on RACF(Resource and Admission Control Functions) in NGN QoS architecture.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.12
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• pp.17-24
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• 2005

Traditional Internet applications such as FIP and E-mail are increasingly sharing bandwidth with newer, more demanding applications such as Web browsing, IP telephony, video conference and online games. These new applications require Quality of Service (QoS), in terms of delay, loss and throughput that are different from QoS requirements of traditional applications. Unfortunately, current Active Queue Management (AQM) approaches offer monolithic best-effort service to all Internet applications regardless of the current QoS requirements. This paper proposes and evaluates a new AQM technique, called MCDT that provides dynamic and separated buffer threshold for each Applications, those are FTP and e-mail on TCP traffic, streaming services on tagged UDP traffic, and the other services on untagged UDP traffic. Using a new QoS metric, our simulations demonstrate that MCDT yields higher QoS in terms of the delay variation and a packet loss than RED when there are heavy UDP traffics that include streaming applications and data applications. MCDT fits the current best-effort Internet environment without high complexity.

• Journal of the Korea Society of Computer and Information
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• v.12 no.6
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• pp.1-9
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• 2007

We propose a novel framework for distributed resource management. The framework has the following novel features. First, the resource management system is distributed using resource content information that is characterized by system properties. We argue that a distributed system based on resource content is sufficient to satisfy specific scheduling requests for Quality of Service(QoS) considering workload balance across a grid. Second, the distributed system constructs a hierarchical peer-to-peer network. This peered network provides an efficient message routing mechanism. The simulation results demonstrate that the proposed framework is proficient to satisfy QoS in distributed environment.

• Journal of Korean Society for Quality Management
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• v.39 no.3
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• pp.412-421
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• 2011

In this paper, we introduce Quality of Service(QoS) analytic model of a distributed system that decentralizes the process nodes performing each task and communicates through a network for cooperation. The model advances a service reliability model of Dai et a1.(2003) by means of considering the processing time. The service is assumed to be provided by a centralized heterogeneous distributed system which is composed of some subsystems managed by a control center. The QoS is defined as the probability that a service is provided successfully in an allowed time, we consider the hardware/software reliability and the processing time which include program execution time, data transfer time. We derive the processing time distribution for a required service through convolution of corresponding probability density function. An application example is used to explain the procedure of computing quality of service.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.05a
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• pp.1083-1088
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• 2005

통신서비스의 QoS에 대한 관심이 증가하면서 서비스품질보증협약(SLA)의 중요성도 증대하고 있다. 통신사업자는 기업 사용자들의 QoS에 대한 요구수준을 만족시켜 주기 위해서 SLA의 제공을 확대하고 있으나, 여전히 통신사업자의 입장에서 SLA의 제공 내용을 설계하는 경향이 있다. SLA의 제공을 통해 달성하고자 하는 목적이 기업 사용자들의 통신서비스에 대한 서비스품질의 개선과 이를 통한 로열티 개선에 있다고 하면 이와 같은 접근과 시도는 앞으로 개선되어야 할 것으로 판단된다. 이와 같은 문제점을 극복하기 위해서 SLA의 제공과 관련, 기업 사용자에 대한 설문조사를 통해 요구사항과 개선방향을 파악해 보는 것은 현재 시점에서 SLA 제공 과정에서 적절한 시도라고 판단된다. 이에 본 논문에서는 SLA 제공과정에서 통신사업자가 고려해야 하는 사항에 대해 주로 서비스품질보증항목 (SLO), 측정(Measurement), 보상(Penalty) 등 SLA의 주요 구성요소 와 차세대 네트워크의 구축에 따라 향후 추가적으로 요구될 수 있는 요소들에 대해 점검해 보고자 한다. 이를 통해 QoS 보장에 대한 가장 유용한 도구로서의 SLA 제공의 활용성과 극대화를 기대해 본다.