• The KIPS Transactions:PartC
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• v.12C no.6 s.102
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• pp.773-780
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• 2005

Recently, the telecommunication network is in a transition toward the BcN (Broadband convergence Networks) that integrates the Internet, the telecommunication and the broadcasting. The BcN makes it possible to provide of 4he third-party application by using the Open API The Parlay X API is an example of the Open API and the Parlay X API is grafted in the Web Service and is abstracted from the Parlay API. So, the Parlay X API does not only have advantages of a Web Service, but also disadvantages of the Web Service. The main disadvantage of the Web Service is that it does not support the any QoS mechanism. In this paper, we propose the architecture that solves the reliability among the QoS issues for the Web Service. The proposed mechanism adopts the Asynchronous architecture for the reliable Web Service and improves the performance of the retransmission between the client and the server using the expected response time. We perform the performance evaluation through the simulation in older to compare with the existing mechanism. Consequently, we can confirm that the performance of the proposed mechanism performs better than the existing mechanism.

• Journal of KIISE:Computer Systems and Theory
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• v.31 no.9
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• pp.527-535
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• 2004

Handling mixed workload in digital set-top box or streaming server becomes an important issue as integrated file system gets momentum as the choice for the next generation file system. The next generation file system is required to handle real-time audio/video playback while being able to handle text requests such as web page, image file, etc. Legacy file system provides only best effort I/O service and thus cannot properly support the QoS of soft real-time I/O. In this paper, we would like to present our experience in developing the file system which fan guarantee the QoS of multimedia stream. We classify all application I/O requests into two category: periodic I/O and sporadic I/O. The QoS requirement of multimedia stream could be guaranteed by giving a higher priority to periodic requests than sporadic requests. The proto-type file system(Qosfs) is developed on Linux Operating System.

• Journal of KIISE:Computer Systems and Theory
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• v.30 no.7_8
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• pp.426-433
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• 2003

Management policies of Web Proxy Cache, for the QoS of Web users, are mainly focused on the page replacement and the data consistency policy. But the two subjects have been studied independently to each other regardless of its possibility of cooperation. In this paper, we introduce the performance improvement obtained by adapting the characteristic of LMF used in data consistency policy to LRU, thus taking the better performance synergy as a result of complementary cooperation. Various policies for the management of Web Proxy Cache are in progress, this study can be a way of performance guide to increase cache hit ratio and reduce the transmission overhead of Web Server.

• The KIPS Transactions:PartA
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• v.10A no.5
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• pp.487-492
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• 2003

To satisfy the requirements for QoS of Users using multimedia content stream service, it is required to control mechanism for QoS based on class priority, URFA classifies the user by two classes (super class, base class) and controls the admission ratio of user's requests by user's class information. URFA increases the admission ratio class and utilization ratio of stream server resources.

• The Transactions of the Korea Information Processing Society
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• v.7 no.11S
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• pp.3651-3667
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• 2000

Recently, in the distributed multimedia environments based on internet, as radical growing technologies, the most of researchers focus on both streaming technology and distributed object thchnology, Specially, the studies which are tried to integrate the streaming services on the distributed object technology have been progressing. These technologies are applied to various stream service mamgements and protocols. However, the stream service management mexlels which are being proposed by the existing researches are insufficient for suporting the QoS of stream services. Besides, the existing models have the problems that cannot support the extensibility and the reusability, when the QoS-reiatedfunctions are being developed as a sub-module which is suited on the specific-purpose application services. For solving these problems, in this paper. we suggested a QoS Integrated platform which can extend and reuse using the distributed object technologies, and guarantee the QoS of the stream services. A structure of platform we suggested consists of three components such as User Control Module(UCM), QoS Management Module(QoSM) and Stream Object. Stream Object has Send/Receive operations for transmitting the RTP packets over TCP/IP. User Control ModuleI(UCM) controls Stream Objects via the COREA service objects. QoS Management Modulel(QoSM) has the functions which maintain the QoS of stream service between the UCMs in client and server. As QoS control methexlologies, procedures of resource monitoring, negotiation, and resource adaptation are executed via the interactions among these comiXments mentioned above. For constmcting this QoS integrated platform, we first implemented the modules mentioned above independently, and then, used IDL for defining interfaces among these mexlules so that can support platform independence, interoperability and portability base on COREA. This platform is constructed using OrbixWeb 3.1c following CORBA specification on Solaris 2.5/2.7, Java language, Java, Java Media Framework API 2.0, Mini-SQL1.0.16 and multimedia equipments. As results for verifying this platform functionally, we showed executing results of each module we mentioned above, and a numerical data obtained from QoS control procedures on client and server's GUI, while stream service is executing on our platform.

• IE interfaces
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• v.21 no.1
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• pp.65-74
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• 2008

In the future, the ubiquitous computing environment will provide users with context-aware services, intelligently interacting with omnipresent resources and surrounding environments at any location and time. Therefore, the ubiquitous computing environment requires context-aware applications in order to gather and analyze context information in various situations. However, existing context-aware applications have mainly focused on providing services and adapting themselves to users based on user related contexts. But this environment requires not only user related contexts but also Quality-of-Service (QoS) related contexts. In this paper we propose a frame-work for supporting user-oriented QoS in ubiquitous environments. The proposed approach adopts a semantic ontology and a neural network algorithm in order to reason about explicit and uncertain contexts. We also show the possibility of applying the framework to real environments such as collaborative engineering service, automobile maintenance service and ubiquitous home service.

• Information and Communications Magazine
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• v.22 no.12
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• pp.105-119
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• 2005

광대역 유선통신망과 무선통신망이 통합되고, 통신과 방송이 융합되는 BcN 환경에서는 서비스 품질(QoS)이 보장되는 다양한 종류의 멀티미디어 서비스가 제공될 수 있어야하며, 다수의 통신방사업자가 제공하는 BcN들 간에 QoS 보장형 차별화서비스 제공을 위한 inter-domain 트래픽 엔지니어링 기능이 제공되어야한다. 특히, BcN 구축 초기 단계에서는 각 통신망 사업자가 개별적으로 구축 및 운영하는 BcN의 NNI signaling과 망운용관리 기능에 많은 차이점이 존재할 것으로 예상되기 때문에, 이들을 효율적으로 연동시킬 수 있는 inter-domain networking 기능 구현방안이 상세히 연구되어야한다. 본 논문에서는 BcN 환경에서의 QoS 보장형 차별화서비스제공을 위한 inter-domain 네트워킹 기술에 대하여 각 영역별로 살펴보며, 상용 BcN간 연동에 적용될 수 있는 트래픽 엔지니어링 및 관련 구현 기술에 대하여 살펴본다. Inter-domain networking 기능 모델로는 유럽연합(EU)의 IP Premium 프로젝트의 일환으로 개발된 MESCAL (Management of End-to-End Quality of Service Across the Internet at Large)을 분석하며, 세부 기능 구현 방안으로 MPLS NNI signaling 기반의 제어정면 연동방안, Web service 구조와 XML 기반의 망운용관리 평면 연동기능 구현 방안에 대하며 살펴본다.

• Annual Conference of KIPS
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• 2007.11a
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• pp.433-435
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• 2007

웹 서비스에 대한 이용과 관심이 증가함에 따라 웹 서비스 어플리케이션을 통해 효율과 유용성을 증가시키기 위한 노력이 이루어지고 있다. 그러나, 웹 서비스를 통해 제공되는 서비스는 기능적인 요구사항을 만족할 뿐 그 외 비기능적인 요소(이용성, 접근성, 비용, 보안 등)을 고려하지 않는다. 본 논문에서는 동적으로 변화하는 현재의 웹 서비스 환경에서 빠른 속도를 고려하며 QoS 를 고려하여 사용자에게 적합한 서비스를 제공해 줄 수 있는 QoS 에이전트 구조를 제안한다.

• Annual Conference of KIPS
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• 2007.05a
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• pp.79-82
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• 2007

XML 기반의 웹 서비스의 활용이 증가 하면서 동일한 기능을 가진 웹 서비스의 개발 또한 날로 증가하고 있다. 따라서 서비스 소비자의 요청에 부합하는 서비스의 검색을 제공하는 문제가 이슈가 되고 있다. 하지만 현재의 웹 서비스 검색은 UDDI에 등록 되어있는 서비스 기능적인 측면 만을 고려한 매칭을 수행 하고 있어, 다양한 소비자의 요구에 만족스러운 결과를 주기 어렵다. 본 논문에서는 이러한 문제점을 개선하고자, 제공된 서비스의 기능적 측면과 비기능적 측면을 모두 고려하고, 사용자 질의에 자주 포함되는 추가적인 QoS 요소를 동적으로 반영함으로써 사용자의 서비스 검색 만족도를 향상시킨다. 또한 서비스 제공자에게 매칭 QoS 요소를 공개함으로써 사용자의 요청에 부합할 수 있는 방안을 제시한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.1B
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• pp.34-44
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• 2003

As the recent rapid development of internet technology and the wide spread of multimedia communications, massive increase of network traffic causes some problems such as the lack of network paths and the bad quality of service To resolve these problems, this paper presents a web-based traffic control system which supports QoS of realtime packet transmission for the multimedia communication The traffic control system presented in this paper applies the integrated service model and provides QoS of packet transmission by means of determining the packet transmission rate according to the policies of network manager and the optimal resource allocation considering the end-to-end traffic load It also provides QoS for the realtime packet transmission through the admission controller and the packet scheduler by the modified $WF^2Q^+$ algorithm support asynchronous and class-based queuing.