• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.4B
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• pp.444-454
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• 2004

To support diverse transmission requirements of multimedia applications, Quality of Service (QoS) should be provided in the Internet, where only the best-effort service is available. In this paper, we describe our recent effort on the implementation and verification of an extendable and flexible QoS allocation and resource management system based on the bandwidth broker model for realizing the IETF differentiated service (DiffServ). Focusing on the bandwidth issue over single administrative domain, the implemented system provides real-time resource reservation and allocation, delayed call admission control, simple QoS negotiation between sewer and users, and simple resource monitoring. The implemented system is verified by evaluating the performance of a resource-intensive application over the real-world testbed network.

• Electronics and Telecommunications Trends
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• v.8 no.4
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• pp.130-142
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• 1993

본 고에서는 통신의 고속화와 다양한 사용자의 요구사항으로 인하여 트랜스포트 계층에서 현재 발생하고 있는 서비스의 정의와 QoS(Quality of Service) 에 대하여 알아보았다. 그리고 이를 토대로 하여 계속 발전하고 있는 하위계층의 요구 사항과 매우 다양해져 가는 상위계층의 요구 사항을 적극 수용할 수 있는 새로운 서비스와 QoS 를 정의하였다.

• Journal of Software Assessment and Valuation
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• v.15 no.1
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• pp.123-131
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• 2019

The Internet of Things (IoT) environment must be able to meet the needs of users by providing access to various services that can be used to develop diverse user applications. However, QoS issues arise due to the characteristics of the IoT environment, such as numerous heterogeneous devices and potential resource constraints. In this paper, we propose a QoS prediction method that reflects trust between users in SOA based IoT. In order to increase the accuracy of QoS prediction, we analyze the trust and distrust relations between users and identify similarities among users and predict QoS based on them. The centrality is calculated to enhance trust relationships. Experimental results show that QoS prediction can be improved.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.60 no.3
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• pp.155-160
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• 2011

IPTV functions not only as media player that does play the broadcasting industry's contents, also as the gateway is guaranteed of QoS(Quality of Service). This is for free contents-sharing that device stores contents using home network circumstance, and is for watching with seamless network service. Also this have required next QoS model that can handle stably as it may contain more data of the small computing device in next generation home system. We need ubiquitous-oriented QoS's design and development project that focuses on internal and external media service, not the existing QoS nor one-sided QoS of media sevice industry. This paper focuses on network module development. This supports IPTV in media industry and two-way capability of QoS highlighting multimedia service in network industry. In additional, this can handle stably the multiplex signal of USN/RFID as the representative ubiquitous and home network that services high-speed wire and wireless interface, and support the seamless u-QoS.

• Journal of Communications and Networks
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• v.9 no.4
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• pp.438-445
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• 2007

In this paper, we consider the problem of optimum selection of quality-of-service(QoS) classes in interworking between the networks in a next-generation-network(NGN) environment. After introducing the delay-cost and loss-cost characteristics, we discuss the time-invariant(TI) and time-variant(TV) scenarios. For the TI case, we show that under nearly lossless transmission condition, each network can make its own optimization regardless of other networks. For the TV case, we present sufficient conditions under which the optimum QoS class of each network can be considered fixed with respect to time without considerable degradation in the optimization target. Therefore, under the conditions presented in this paper, the QoS of a flow in each network can be determined solely by considering the characteristics of that network and this QoS class can be held fixed during the flow period.

• Journal of Communications and Networks
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• v.9 no.4
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• pp.356-367
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• 2007

In large networks, maintaining precise global network state information is impossible. The imprecise network state information has significant impacts on Quality-of-Service(QoS) routing and path establishment. In this paper, we develop analytical models for investigating the QoS routing schemes that are designed to tolerate imprecise network state information, and study the performance of various QoS routing schemes, including randomized routing, multi-path routing, and probability based routing, using both the models and simulations. We further propose a new mechanism, called local rerouting, that improves the effectiveness of QoS path establishment in the presence of imprecise global network state information. Local rerouting is orthogonal to existing schemes for dealing with imprecise state information and can be used in conjunction with them to alleviate the impacts of the imprecise information. The results of our performance study indicate that local rerouting is robust and effective.

• 한국정보통신설비학회:학술대회논문집
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• 2009.08a
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• pp.320-325
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• 2009

네트워크 서비스에 있어서 품질을 정확히 측정하고 품질지수를 도출하는 것은 매우 중요하다. 종래의 네트워크 서비스에 대한 품질지수는 QoS(Quality of Service)로서 많은 연구가 있어왔다. 하지만 QosS를 통한 사용자 품질지수는 실제 사용자의 서비스 만족도를 효과적으로 표현해 주지 못하였다. 그래서 본 연구에서는 QoE(Quality of Experience)라는 개념을 도입하여, 사용자가 실제로 느낀 서비스의 만족도를 도출하고자 하였다. 사용자의 서비스 만족도를 잘 표현해주는 QoE를 도출하기 위하여 본 연구에서는 QoE Framework를 제안한다. QoE Framework는 framework를 위해 동작하는 agent들로 구성된다. QoE Framework의 agent는 크게 서비스 제공자측과 서비스 사용자 측으로 나눌 수 있는데, 서비스 사용자 측의 agent는 서비스를 이용하다가 사용자가 서비스 불만족을 감지하였을 때, 서비스 제공자측 agent는 사용자측 agent로부터 받은 서비스 불만족에 대한 feedback으로부터 QoE도출 알고리즘을 사용하여 최적의 QoE를 도출하는 기능을 한다. 서비스 제공자측 agent의 QoE도출 알고리즘으로 GA(Genetic Algorithm)을 사용하여 최적의 값을 구하게 된다. QoE framework의 알고리즘에서는 불만족 feedbaek을 이루는 QoS 파라미터들간의 중요도와 관계를 도출하여, 주어진 서비스 개선 비용으로 최적의 QoE를 도출함으로써, 네트워크 서비스에 대한 사용자의 만족도를 최대로 높이는 결과를 도출하게 된다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.12B
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• pp.2320-2334
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• 1999

In this paper, we propose multiple IS-MMBS service schemes for very low power and micro-size RMIMS (radio-interfaced micro information monitoring system) terminals. In MMBS service area, when new arrival RMIMS terminals have real-time traffic characteristic or large traffic bandwidth, only single IS-MMBS service scheme can not guarantee RMIMS terminal's QoS(quality of service) such as buffer overflow or packet loss. In this case, the proposed multiple IS-MMBS service schemes can be effectively used for QoS service of RMIMS terminal. According to clustering method of RMIMS terminals and MMBS segment method, the proposed schemes can be divided into terminal segment method, region segment method, application based segment method, traffic type based segment method, overlapping segment method and hybrid segment method

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.9B
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• pp.802-812
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• 2008

This paper proposes QoS Model which has tested and analyzed the capabilities of provisioning multimedia service in high speed Internet environment. We have tested quality measurement test for VoIP/MoIP, VoD, IPTV services and analyzed the level of QoS and QoS degradation by constructing test laboratory consisted of 46 subscribers which provided by 3 telecom operators. Besides, We propose QoS Model to apply for BcN application based on analysis result and prove proposed model by constructing test lab in KOREN environment. It is expected that telecom will use this results as a valuable information to construct All-IP network based on NGN(NGN:Next Generation Network).This paper proposes QoS Model which has tested and analyzed the capabilities of provisioning multimedia service in high speed Internet environment. It is expected that telecom will use this results as a valuable information to construct All-IP network based on NGN.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.12
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• pp.18-26
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• 2003

In this paper, we design and implement a QoS control function in the SIP-based VoIP system. As a network infrastructure for VoIP service, we select the Intserv over Diffserv architecture where the network resources are managed by a call admission control mechanism. The SIP protocol extended to support QoS signaling procedure is modulized to operate independently with the infrastructure. The performance of the QoS-enabled VoIP system is verified by experiments.