• 전자공학회논문지
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• 제52권6호
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• pp.144-150
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• 2015

본 논문은 분산된 센서 디바이스의 리소스 오브젝트 연동 서비스 제공 시스템에 관한 것으로 서비스 전달 플랫폼을 기반으로 한다. 시스템은 서비스 전달 플랫폼(SDP: Service Delivery Platform)과 프록시로 구성되어 있다. 서비스 전달 플랫폼은 분산된 서비스 기능을 인에이블러로 설정하며 인에이블러들의 조합으로 융합서비스를 생성한다. 또한 생성된 서비스를 분산 환경에서 전달하는 역할을 한다. 프록시는 분산된 디바이스들과 서비스 전달 플랫폼을 연결하도록 설정되며 서비스 전달 플랫폼이 분산된 디바이스를 자원으로 인식하여 인에이블러로 정의할 수 있도록 한다. 개발된 시스템을 통하여 분산된 센서 기능이 인에이블러로 정의되어 일반 서비스 기능과 동일한 형태로 융합서비스의 생성 및 전달에 사용될 수 있다.

• 한국정보처리학회논문지
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• 제6권3호
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• pp.562-570
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• 1999

Information superhighway and improvement of computing power result in increase of the requirements for distributed multimedia applications. But, developer of applications needs much time and efforts because of the difficulties of development, enhancement and maintenance of distributed applications. To solve this problem, CORBA is used widely. But, the definitions of CORBA services are required for the brief developments of distributed multimedia applications. Especially, collaboration service is required because multiple users use distributed multimedia service. Collaboration service manages user and group information of applications and makes the interoperability between of multi users. In this paper, we designed collaboration service for CORBA based distributed multimedia applications. Collaboration service is able to maintain group information and to present the ability for collaborative works between of multi users. Application developers can develop the applications easily because the ability of collaborative works is offered by collaboration service.

• International Journal of Contents
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• 제2권2호
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• pp.29-31
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• 2006

Mobile Ad hoc network is a self configuring network of mobile nodes. It allows mobile nodes to configure network spontaneously and share their services. In these networks, service discovery is very important because all nodes do not have same resources in term of memory and computing power. Nodes need to use different services offered by different servers. Some service discovery protocols have been proposed in last couple of years but they include significant traffic overhead and for small scale MANETS. In this paper, we present extensible lookup service scheme based on distributed mechanism. In our scheme neighboring nodes of service provider monitor service provider and send notification to lookup server when the service provider terminates its services unexpectedly. Lookup server can find other service provider or other alternative services in advance because of advance notification method and can provide consistent lookup services. In our scheme neighboring nodes also monitor lookup server and send notification to network when lookup server terminates unexpectedly. Simulation results show that our scheme can reduce up to 70% and 30% lookup failure as compare to centralize and simple distributed mechanism respectively.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권2호
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• pp.577-594
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• 2020

Service Function Chaining (SFC) supports services through linking an ordered list of functions. There may be multiple instances of the same function, which provides a challenge to select available instances for all the functions in an SFC and generate a specific Service Function Path (SFP). Aiming to solve the problem of SFP selection, we propose an architecture consisting of distributed SFP algorithm and central control mechanism. Nodes generate distributed routings based on the first function and destination node in each service request. Controller supervises all of the distributed routing tables and modifies paths as required. The architecture is scalable, robust and quickly reacts to failures because of distributed routings. Besides, it enables centralized and direct control of the forwarding behavior with the help of central control mechanism. Simulation results show that distributed routing tables can generate efficient SFP and the average cost is acceptable. Compared with other algorithms, our design has a good performance on average cost of paths and load balancing, and the response delay to service requests is much lower.

• 한국멀티미디어학회논문지
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• 제12권7호
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• pp.883-892
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• 2009

분산서비스 객체들의 효율적인 연동을 제공하기 위해 제시된 WSDL기반의 SOAP메시지 방식이 제시되었으나, 이 방식에서 사용하는 SOAP메시지와 객체참조문서(WSDL)는 해당 객체의 개발환경에 의존적이므로 서로 다른 개발환경에서 개발된 객체들의 통합을 위해서는 SOAP 메시지와 객체참조문서(WSDL)의 개발환경 의존성을 해결하여야 한다. 본 논문에서는 이종 분산객체 환경에서 객체들의 통합을 지원하기 위해 SOAP Bridge, WBSB (WSDL, Based SOAP Bridge)를 제안, 구현하였다. 서비스 요청 메시지를 WSDL 저장소의 WSDL문서를 참조하여 해당 서비스 객체에 적합한 SOAP 메시지로 변경한 후, 이를 서비스 객체에게 전달하는 기능을 WBSB에서 수행함으로써 사용자는 사용하고자 하는 객체의 개발환경을 고려하지 않고도 해당 서비스를 이용할 수 있다.

• 품질경영학회지
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• 제39권3호
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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.

• 인터넷정보학회논문지
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• 제11권1호
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• pp.153-165
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• 2010

본 논문에서는 분산응용의 관점에서 네트워크 상에 응용을 구성하는 분산된 객체들을 효율적으로 관리하는 분산객체그룹 프레임워크를 기반으로 사용자 맞춤형 분산응용 서비스를 제공하는 프로액티브응용서비스엔진을 제안한다. 본 엔진은 물리계층, 미들웨어 계층, 응용 계층으로 구성되며, 사용자의 요청에 의해 하드웨어 기기로부터 수집된 데이터 및 응용을 구성하는 객체의 속성정보를 그룹으로 관리하는 그룹서비스와 수집된 데이터 및 객체에 대한 사용자의 권한별 접근을 관리하는 보안서비스, 수집된 데이터를 추출 및 가공하여 응용에 제공하는 필터링서비스, 과거의 데이터를 이용한 통계서비스, 수집된 데이터를 토대로 현재의 운영 상태를 진단하는 진단서비스, 통계서비스와 진단서비스를 통해 미래의 발생 가능한 상황을 예측하기 위한 예측서비스를 제공한다. 최종적으로 엔진이 제공하는 서비스의 수행성을 검증하기 위하여 유비쿼터스 농업 분야의 온실 자동제어 응용에 적용하여 결과를 확인했다.

• Journal of Communications and Networks
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• 제14권6호
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• pp.597-605
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• 2012

With the smart grid coming near, wide-area supervisory control and data acquisition (SCADA) becomes more and more important. However, traditional SCADA systems are not suitable for the openness and distribution requirements of smart grid. Distributed SCADA services should be openly composable and secure. Event-driven methodology makes service collaborations more real-time and flexible because of the space, time and control decoupling of event producer and consumer, which gives us an appropriate foundation. Our SCADA services are constructed and integrated based on distributed events in this paper. Unfortunately, an event-driven SCADA service does not know who consumes its events, and consumers do not know who produces the events either. In this environment, a SCADA service cannot directly control access because of anonymous and multicast interactions. In this paper, a distributed security framework is proposed to protect not only service operations but also data contents in smart grid environments. Finally, a security implementation scheme is given for SCADA services.

• 인터넷정보학회논문지
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• 제18권6호
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• pp.47-53
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• 2017

Recently, huge datasets have been generating rapidly in a variety of fields. Then, there is an urgent need for technologies that will allow efficient and effective processing of huge datasets. Therefore the problems of partitioning a huge dataset effectively and alleviating the processing overhead of the partitioned data efficiently have been a critical factor for scalability and performance in distributed database system. In our work we utilized multicore servers to provide scalable service to our distributed system. The partitioning of database over multicore servers have emerged from a need for new architectural design of distributed database system from scalability and performance concerns in today's data deluge. The system allows uniform access through a web service interface to concurrently distributed databases over multicore servers, using SQMD (Single Query Multiple Database) mechanism based on publish/subscribe paradigm. We will present performance results with the distributed database system built on multicore server, which is time intensive with traditional architectures. We will also discuss future works.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권9호
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• pp.2194-2212
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• 2013

The multicast routing architectures have become indispensable due to the increasing needs for extreme communication services anywhere and anytime. The most recent approaches are called hierarchical and fully distributed, what have been proposed by O. Said et al. in a previous work. These proposed architectures were introduced to enhance the service-centric approach. In this paper, NS2 is used to build a simulation environment to test the hierarchical and the fully distributed multicast architectures as regards the service-centric one. The results of simulation show that the performance of the hierarchical and the fully distributed architectures outperforms the service-centric architecture. Furthermore, the fully distributed architecture is found to have the best performance.