• Proceedings of the Korean Information Science Society Conference
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• 2007.10c
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• pp.90-95
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• 2007

유비쿼터스 환경에서는 서비스 사용자가 언제, 어디서나 모든 서비스를 사용할 수 있어야 한다. 즉, 디바이스나 서비스의 상태, 위치 정보 등 특성에 관계 없이 동질의 서비스를 제공해야 한다. 이를 위해 산재한 이질적인 서브네트워크의 상호운용성을 위한 다양한 분산 시스템의 네트워크 프로토콜과 디바이스간의 통신을 통합하기 위한 연구가 필요하다. 서브네트워크의 상호운용성을 위해서는 메시지 전송 및 변환 기능이 요구되며, 서브네트워크의 변화를 동적으로 감지하여 서비스 사용자에게 알려주어야 한다. 따라서 본 연구에서는 유비쿼터스 웹서비스를 지원하기 위한 Web Services on Universal Networks를 제안하였다. 제안하는 WSUN은 Universal Service Broker의 프레임워크를 통해 SOA 기반으로 접근하고 있으며 요구 사항을 정의하여 필요한 구성 요소에 대한 설계하였다. 또한, 동적인 서비스 검색을 위한 Universal Service Registry를 사용한다. 본 논문에서는 DPWS의 동작 시나리오를 통해 이질적인 서브네트워크의 상호운용성을 지원하기 위한 DPWS 어댑터를 설계한다.

• The KIPS Transactions:PartB
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• v.15B no.4
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• pp.315-322
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• 2008

It is important to retrieve effectively the visual media such as pictures and video in the internet, especially to the application areas such as electronic art museum, e-commerce, and internet shopping malls. It is also needed in these areas to have content-based or even semantic-based multimedia retrieval instead of simple keyword-based retrieval. In our earlier research, we proposed a semantic-based visual media retrieval framework for the effective retrieval of the visual media from the internet. It uses visual media metadata and ontology based on the web service to achieve the semantic-based retrieval. In this research, there are more than one visual media service providers and one central service broker. As a preliminary step to the visual media data retrieval, a method is proposed to retrieve the service providers effectively. The method uses the structure of the ontology tree to obtain the providers and their rankings. It also uses the size of sub nodes and child nodes in the tree. It measures the rankings of providers more effectively than previous method. The experimental results show the accuracy of the method while keeping compatible speed against the existing method.

• KIISE Transactions on Computing Practices
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• v.20 no.12
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• pp.664-669
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• 2014

As the prevalence of cloud computing increases, various cloud service types have emerged, such as IaaS, PaaS, and SaaS. The growth and diversification of these cloud services has also resulted in the development of technology for cloud service brokers (CSBs), which serve as intermediate cloud services that can assist cloud tenants (users) in deploying services that fit their requirements. In order to broker cloud services, CSBs require the specification of structural models in order to facilitate the analysis and search for cloud services. In this study, we propose a variability-based service analysis model (SAM) that can be used to describe various cloud services. This model is based on the concept of variability in the software product line and represents the commonality and variability of cloud services by binding variants to each variation point that exists in the specification, quality, and pricing of the services. We also propose a virtual cloud bank architecture as a CSB that serves as an intermediate to provides tenants with appropriate cloud services based on the SAM.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.2B
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• pp.105-116
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• 2003

The differentiated service architecture is based on a simple model by applying a per-class service in the core node of the network. However, due to the simplified network behavior, the network structure and provisioning were more complicated. If a service provider wants the dynamic provisioning or better bandwidth guarantee, signaling protocol with QoS parameters or admission control method should be deployed in DiffServ network. However, these methods increase the complexity. Therefore, we proposed DPM2 mechanism for admission control in the DiffServ network. In this paper, we describe and survey the admission control methods that are applicable to IP networks and propose also the dynamic provisioning mechanism based on the bandwidth broker and distributed measurement based admission control and movable boundary bandwidth management to support heterogeneous QoS services in differentiated service networks. For the performance evaluation for proposed mechanism, we used ns-2 simulator.

• The KIPS Transactions:PartC
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• v.13C no.6 s.109
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• pp.717-724
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• 2006

This paper describes the design and implementation of architecture for convergence of home network services and data broadcasting services based on UMB and ACAP middleware; the one is used for interoperability of home networked devices, and the other for data broadcasting services. The proposed architecture provides TV-centric user interface capable of managing home network services and data broadcasting services together using a remote controller and TV sets TV applying Java TV Xlet interface and HAVi user interface for home network services like data broadcasting services. Besides, we define the service proxy for accessing home network services in a set-top box and the service broker for providing data related to home network services in a home server. Finally, the application manager in ACAP middleware manages the lifecycle of home network services through service events from the service proxy to the application manager.

• The Transactions of the Korea Information Processing Society
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• v.5 no.4
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• pp.975-983
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• 1998

In these days, information communication systems are based on both open distributed computing technologies and object-oriented techniques like inheritance, encapsulation and object reuse to support various system configuration and application. As information systems are interconnected through unsecure networks, the need for the secure information exchange is more critical than before. In this paper, we have designed and implemented a transparent CORBA-basce Security infrastructure with authentication, security context association, access control and security information management to support a secure applications in distributed object environment. SESAME Ver. 4 was adopted as an external security service to manage user privilege attributes and to distribute keys for data encryption, decryption and integrity. Using filter and transformer with an interface to Object Request Broker, it provides a transparent security service to applications. The filter objects are special classes that allow additional parameters to be inserted into messages before they are sent and removed just after they are received. The transformer objects are special classes that allow direct access to the byte stream of every messages for encryption and decryption before it is sent and just after it is received. This study is to implement the access control interceptor(ACI) and the secure invocation interceptor(SII) of secure ORB defined in CORBA using filter and transformer.

• The KIPS Transactions:PartC
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• v.11C no.6 s.95
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• pp.799-806
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• 2004

A growing diversity of pervasive devices is gaming access to the Internet and other information. However, much of the rich multimedia contents cannot be easily handled by the client devices because of the limited communication, processing, storage and display capabilities. The in-tegration of voice, data and video service modified the target of networking technologies. Networks must have some the capabilities for in-tegration of various services and also for QoS support as required by each of those service. Because of these reasons, we developed EAGIS(Efficient ATM Gateway for real time Internet Service) to provide seamless multimedia service between the ATM network and the Internet. EAGIS consists of the interworking unit, content server, transcoding server, and the serveice broker to provide seamless multimedia service be-tween the ATM network and the Internet. In this paper, we design the architecture and transcoding service scenario of the EAGIS. When the RTP is used for the bi-directional communication, transcoding time is configured by the time-stamp of RTCP. When HTTP is used for unidirec-tional communication, self-timer is used. By using these reference time, standard transcoding method is applicable according to the frame trans-mission rate and network traffic load. And we can also assure the QoS of the multiple users` effective bandwidth by our algorithm.

• Proceedings of the CALSEC Conference
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• 2005.03a
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• pp.130-134
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• 2005

This research describes the comparison broker's role and its effectiveness measurement using a developed logical framework of comparison shopping service. And verifies that seller-led comparison challenge method provide comparison information of products to buyers more efficiently. In electronic commerce, buyer's satisfaction of purchase (S) can be defined as an interactive function between seller's competitiveness vector (P) of products that supplied to the market, and buyer's informed level vector (B) of products that is known from a lot of sources. Then the buyer's informed level can be changed through the information analysis among products by transformation process using comparison matrix (C). So the role of comparison shopping is to construct a comparison matrix and to serve it to the buyers, and to change the buyer's informed level. The changed informed level influences a buyer's satisfaction, that improved satisfaction of purchase is defined as the effectiveness of comparison shopping. As a perfect provision and usage of comparison matrix is impossible cause of cognitive limit, the most efficient method for improving the comparison effectiveness is the comparison challenge that detects the comparison elements of the largest buyer's information efficiency, and then to be compared between elementary products selectively. This research verifies the substantial superiority of comparison challenge through television market data experiments.

• Proceedings of the Korean Information Science Society Conference
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• 1999.10c
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• pp.200-202
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• 1999

이벤트 서비스는 멀티미디어 통신, 전자상거래, 트래픽 제어시스템 등과 같은 대용량의 분산 응용 시스템에서 발생하는 이벤트의 전송을 제어하기 위한 서비스이다. 하지만 기본의 이벤트 서비스는 분산 환경의 실시간 응용 서비스를 지원하기 위해 필요한 실시간 이벤트 필터링, 우선순위, 마감시간 등과 같은 실시간 QoS 지원 기능들이 결여되어 있어 이를 지원할 수 있는 실시간 이벤트 서비스 처리 방안이 요구된다. 본 논문에서 제안하는 RTES는 기존의 ORB 구조에 이벤트 필터링, 실시간 매니저 및 QoS 저장소를 포함시킨 실시간 이벤트 서비스 미들웨어이다. 특히, RTES는 이벤트 사용자의 실시간 요구사항을 분산 실시간 응용에 반영시키기 위하여 이벤트 필터링 기능을 실시간 처리에 맞게 강화 시켜 기존의 시스템에서 지원하지 못한 사용자의 실시간 요구 사항을 지원하는데 중점을 두었다. 실시간 이벤트 필터링은 사용자로부터 원하는 실시간 요구사항과 사용자가 원하는 자신만의 이벤트 필터링 정보를 입력받아 QoS 저장소에 저장하고, 실시간 이벤트 발생 시 사용자가 입력한 정보를 반영한 필터링을 통해 이벤트를 처리하는 메커니즘으로써 사용자는 자신이 원하는 실시간 요구조건에 맞게 필터링된 이벤트 처리결과를 얻게 되어 궁극적으로 보다 높은 서비스(QoS)를 제공받게 된다. 또한 이 과정을 통해 불필요한 이벤트가 필터링 됨으로써 전체적인 네트웍 트래픽(traffic)을 감소시키는 효과를 가져온다.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.05a
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• pp.297-300
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• 2005

최근 웹 관련 기술들의 개발 및 표준화로 인하여 서비스 지향 아키텍처(SOA: Service Oriented Architecture)기반의 비즈니스 어플리케이션 개발이 가능해짐에 따라 SOA 가 개발 방법의 새로운 패러다임으로 IT 분야의 주목을 받고 있다. 이와 관련하여 SOA 기반의 소프트웨어 개발에 대한 많은 연구가 진행되었으며, 이를 바탕으로 IT 분야에서 시장 형성이 진행되고 있다. 그러나 시장 측면에서 볼 때 SOA 기반의 비즈니스 어플리케이션 개발을 실제 적용하기에는 이용 가능한 서비스들이 아직은 부족한 상태이며, 사용자들에게 서비스 이용에 대한 신뢰성과 안정성에 대한 요구를 충족 시키지 못하고 있다는 점이다. 이는 SOC 환경의 활성화를 저해하는 결정적 장애요인이며, 더욱 심각한 문제는 대다수의 연구들이 서비스 시장에서 대체 서비스가 존재한다는 가정하에 진행되고 있어 웹 서비스의 도입 초기에 발생할 수 있는 대체 서비스가 존재하지 않는 문제점에 대해서는 간과하고 있는 점이다. 이러한 문제를 해결하기 위해 본 논문에서는 확장된 서비스 중개자(Extended Broker) 개념과 구현 방안을 제시함으로써 성숙되지 않은 웹 서비스 환경에서 서비스 요청자에게 제공되는 서비스 사용에 대한 안정성과 신뢰성을 보장하고자 한다.