• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.4C
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• pp.295-307
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• 2002

The IEEE 1394 protocol is a de facto standard in multimedia digital home network. It supports several advanced features such as hot plugging, dynamic network reconfiguration, isochronous transmission and so on. Since the IEEE 1394 was adapted in the field of multimedia service with QoS guarantee, back bone network protocol with reel-time digital instrumentation and control sub networks, and physical layer protocol for real-time middleware such as real-time CORBA, the additional real-time features has been required in device driver implementation because of the necessity of the predictability enhancement. To guarantee the real-time features, the device driver of the IEEE 1394 should support the priority based packet processing and also need a isochronous buffer management mechanism to deal with the periodic isochronous communication. In this paper, we proposed a new software architecture of the IEEE 1394 device driver for supporting the real-time characteristics such as priority based packet processing, priority based scheduling and so on.

• The Transactions of the Korea Information Processing Society
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• v.6 no.7
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• pp.1897-1908
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• 1999

Multimedia services(i.e. teleconferencing and Video on demand) have been developed on MBone. The video and audio data of them require Real-Time service using QoS(Quality of Service) guarantees. RSVP(Resource reSerVation Protocol) on the Internet has been suggested to support QoS guarantees. But currently, it has two problems : complexity and scalability. To solve these problems, this paper describes the design and implement of teleconferencing system with QoS guarantees by simplifying the resource reservation processing to solve the RSVP's complexity and scalability.

• Journal of Internet Computing and Services
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• v.3 no.2
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• pp.79-85
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• 2002

In open communication architecture, application systems consist of objects distributed in lots of computing nodes. To reduce complexity of development. and management of distributed software, to manage efficiently distributed objects and to provide realtime service, the mechanisms for object group management and communication are needed in distributed environment. In this paper we compose object groups and provide reliable group communication mechanism based on CORBA which can adopt a new service without lots of changes on existing system. Group consist of some subgroups that subgroup manager manages for improving the efficiency of group management and message ordering is kept by using sequencer, Communication method among groups uses multicast based on paint to point communication as well as IP multicast and we provide high performance by using selective retransmission of message through message history, We analyze the performance of the proposed mechanism through simulation in distributed environment.

• The Transactions of the Korea Information Processing Society
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• v.7 no.4
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• pp.1062-1072
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• 2000

The applications developing in distributed object computing enviroments are faced with the difficulties for managing various lots of distributed objects. Also, because the most multimedia service, like video, audio, and so forth, must be satisfied itself with real-time constraints, the users also are feeling with necessary to apply real-time mechanisms to distributed multimedia services. The goal of this paper is to solve the problems for managing distributed objects, and to be easy to develop complex applications that can provide real-time services. To do this, we designed and implemented a real-time object group platform that can be placed between applications and CORBA. This platform is extended the existing object group model[13,14] added to the scheduler and timer object components for supporting real-time concept. We designed the components for platform by using James Rumbaugh object modeling technology that consists of object, function, and dynamic model. And then we described the detailed interfaces of the components by IDL, and implemented our real-time object group's platform using OrbixMT 22 which is the IONA Technologies' ORB product. Finally, we showed the execution procedures of the schduler object of each components in a real-time object group platform.

• Journal of the Korea Society of Computer and Information
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• v.8 no.3
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• pp.53-60
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• 2003

In these day, Digital Contents is authorized in forms of HTML and various kind of multi-media by an enterprise and/or organization. At this circumstances, it is very hard or impossible to search a contents between them. Futhermore, you may have to change your contents service systems to extend to cover more user services needs. On this paper, we propose a new architecture to get extendability and empowered interoperability without any maintenance, update or changes. And we introduce the OMG's CORBA to make fault resilient system and to provide a load balancing using a distributed process mechanism. Even more, we adopted the SyncML specification. It can help us to make it real to synchronize between DBMS at real-time. So all these are support easy content synchronization and user-friendness.

• The Transactions of the Korea Information Processing Society
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• v.6 no.5
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• pp.1241-1252
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• 1999

It is proposed in TINA, the open information telecommunication network architecture, that the definition of object group which is collection of objects provides a decrease of complex networking and a facility of object managing by service executing of application on distributed computing environment. Based on a new distributed object group model[13] we have been researched according to TINA specification, this paper proposed the object group model with the scheduler object and objects management mechanisms that can support real-time services on CORBA. To do this, we described the definition of object grouping and the requirements to suggest the object group model supporting real-time service, designed the object group structure and functional components containing in an object group using James Rumbaugh's modelling[12], and showed a class diagram of components in an object group. This paper designed IDLs of an object group manager and scheduler among the components, and finally showed the procedures of management and service interconnections between objects in the different object groups vi ETD.

• 한국IT서비스학회:학술대회논문집
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• 2003.11a
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• pp.637-642
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• 2003

현재 각 기업 및 기관에서 구축하고 있는 디지털 콘텐츠는 HTML을 비롯한 다양한 형식의 멀티미디어로 작성되어 있다. 따라서 타 기관에 전시된 콘텐츠 정보를 검색하거나 연동하기는 불가능하다. 뿐만 아니라 시스템을 확장하기 위해서는 전체 시스템을 교체해야하는 문제도 파생될 수 있다. 그러나 본 연구에서 제안하는 플랫폼은 기존 레거시(Legacy) 어플리케이션을 수정하지 않더라도 쉽게 신 시스템과 연동이되고 타 시스템과도 연동이된다. 또한 CORBA에 기반한 부하 분산 기법과 분산 처리기법을 도입하여 하나의 시스템에 과부하가 발생하여 전체시스템의 성능이 저하되는 문제를 방지하고 안정성을 보장하기 위하여 Fail-over 기능을 제공한다. 또한 SyncML 기법을 도입하여 여러 종류의 DBMS를 사용하는 타 기관과의 콘텐츠 실시간 공유를 지원한다. 이로써 콘텐츠를 쉽게 저장 및 유통할 수 있는 기반 환경을 제공한다.

• The KIPS Transactions:PartD
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• v.10D no.1
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• pp.109-116
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• 2003

In this paper, a CORBA-based collaborative medical image analysis and visualization system, which provides high accessibility and usability of the system for the users on distributed environment is introduced. The system allows us to manage datasets and manipulates medical images such as segmentation and volume visualization of computed geometry from biomedical images in distributed environments. Using Bayesian classification technique and an active contour model the system provides classification results of medical images or boundary information of specific tissue. Based on such information, the system can create real time 3D volume model from medical imagery. Moreover, the developed system supports collaborative work among multiple users using broadcasting and synchronization mechanisms. Since the system is developed using Java and CORBA, which provide distributed programming, the remote clients can access server objects via method invocation, without knowing where the distributed objects reside or what operating system it executes on.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.6A
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• pp.1019-1033
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• 2001

본 논문에서는 멀티미디어 스트리밍을 위한 표준 프로토콜과 미디어 포맷을 지원하고, 실시간 객체지향형 멀티미디어 데이터베이스(BeeHive)를 지원하는 통합 멀티미디어 스트리밍 서비스 프레임워크(ISSA)를 제안한다. ISSA의 핵심 구성요소는 세션의 생성과 스트림 제어를 담당하는 세션 관리자, 스트리밍 데이터의 전송을 담당하는 전송 관리자, 미디어의 압축과 복원 및 재생을 담당하는 미디어 관리자, 그리고 데이터베이스와의 연동을 담당하는 데이터베이스 커넥터이다. ISSA는 스트림의 제어를 위하여 IETF에서 제안한 RTSP, 스트림과 세션의 표현과 초기화를 위해 SDP와 SIP, 스트림 데이터의 실시간 전송을 위하여 RTP 및 TCP, UDP를 지원한다. 또한, ISSA는 VOD, MOD, 웹캐스팅을 위한 개발과 라이브러리를 제공하며, 웹서버와 CORBA A/V 스트리밍 서비스와의 연동을 위한 게이트웨이도 제공한다. ISSA는 운영체제 환경에서 플랫폼에 독립적으로 작동하고, 객체지향 멀티미디어 데이터베이스 서비스를 지원한다. 그리고 멀티캐스팅, 웹캐스팅, 멀티미디어 통신을 위한 표준 프로토콜을 지원하며, 상용 코덱인 Microsoft 사의 Direct Show를 지원할 수 있는 RTP 소스필터를 가지고 있다. 마지막으로, 기존의 다양한 표준 미디어 포맷을 지원할 뿐만 아니라, 새로운 미디어 포맷도 쉽게 수용할 수 있도록 설계되어 있다.

• Journal of Advanced Navigation Technology
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• v.13 no.5
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• pp.705-713
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• 2009

This paper proposes CORBA-based visual servoing system of humanoid robot. To effectively control the humanoid robot which is connected to network, it needs to define necessary services for visual servoing as distribution object, and realize them in the middleware. For realizing it following services should be addressed. Naming service for searching a necessary service with unique name assigned to each object, image service for supplying image obtained from stereo camera. In the experiment, we show the result of balloon tracking and bursting that the robot tracks balloons as target objects in the real time, and if a balloon stop for a certain time, then the robot bursts the balloon.