• Journal of Advanced Marine Engineering and Technology
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• 제28권4호
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• pp.603-610
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• 2004

Time delays are included in most of actual systems, and some of which are shown as time varying. To analyze the time varying time delay system in the time domain. a useful delay module to express the function as a tool is much helpful to get corresponding outputs under given conditions. A method is proposed here to design the algorithm of time delay module for simulation or control purposes, including the problems of initializing and reallocating data in buffer. After classifying the time varying time delay into the distributed mode and lumped mode, an object to describe delay module is configured and tested under the defined input signal and given time delay variation. The simulation results show that the output of module matches reasonably with the case of real system.

• 전자공학회논문지CI
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• 제41권6호
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• pp.23-37
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• 2004

자바의 쓰레드는 다중 처리 환경에서 하나의 프로그램 공간 내의 독립적인 프로세스로 취급되는 객체 요소이므로 병렬처리를 위한 독립적인 프로세스로 활용할 수 있다. 또한, 자바의 동기화 메커니즘과 쓰레드를 활용하면 병렬 처리를 수행하는 응용프로그램을 쉽게 작성할 수 있다. 이에 따라, 자바의 병렬 처리 지원 기능을 분산된 컴퓨팅 환경에 적용하기 위한 많은 연구 결과가 있다. 본 논문에서는 레거시 자바 프로그램에 포함된 쓰레드를 분산된 컴퓨팅 환경에서 병렬 수행 하도록 지원하는 시스템 환경을 제안한다. TORB(Transparent Object Request Broker)라고 명명된 본 시스템은 프로그래밍 투명성을 지원하므로 이미 작성된 레거시 자바 프로그램을 간단한 변환 과정을 거친 후 병렬 수행 하도록 지원한다. TORB는 본 연구팀에서 이미 발표한 분산 프로그래밍 도구의 기능을 확장한 것이며, 이는 지정된 기능을 지정된 컴퓨터에서 수행하도록 지원하는 전형적인 분산처리 기능만을 보유하고 있었다.

• 한국정보통신학회논문지
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• 제10권1호
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• pp.74-79
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• 2006

본 논문에서는 RMI와 JMF를 이용하여 분산 미디어 객체 실시간 스트리밍을 하기 위한 기법을 제시한다. 즉, 분산 객체의 복잡한 제어를 RMI를 사용하여 간소화 하고 멀티캐스트를 지원하지 않는 네트워크 환경에서 JMF를 사용하여 일대다 실시간 스트리밍을 하기 위한 기법을 다룬다. 자바 기반의 RMI와 JMF를 사용하여 전송과 제어를 분리 할 수 있으며 이를 응용하여 플랫폼에 독립적인 멀티미디어 서비스 애플리케이션의 개발에 사용 가능하다.

• 산업공학
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• 제15권1호
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• pp.10-19
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• 2002

New trends such as electronic commerce, virtual organizations, e-business applications, etc. increase the dependence of production management on information software systems and contribute to the needs for global, distributed object systems. This paper presents a component based approach for production management systems under the multi-tier distributed information system architecture using UML(Unified Modeling Language), CORBA(Common Object Request Broker Architecture) and XML(eXtensible Markup Language) technologies, and propose rules for mapping a UML class diagram to a XML DTD (Document Type Definition). And we adapt it to the prototype system implementation. The components are implemented by CORBA and we use XML messages for the information exchange between components.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제5권1호
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• pp.46-51
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• 2005

Intelligent Space(ISpace) is the space where many intelligent devices, such as computers and sensors, are distributed. According to the cooperation of many intelligent devices, the environment, it is very important that the system knows the location information to offer the useful services. In order to achieve these goals, we present a method for representing, tracking and human following by fusing distributed multiple vision systems in ISpace, with application to pedestrian tracking in a crowd. And the article presents the integration of color distributions into particle filtering. Particle filters provide a robust tracking framework under ambiguity conditions. We propose to track the moving objects by generating hypotheses not in the image plan but on the top-view reconstruction of the scene. Comparative results on real video sequences show the advantage of our method for multi-object tracking. Simulations are carried out to evaluate the proposed performance. Also, the method is applied to the intelligent environment and its performance is verified by the experiments.

• 한국정보처리학회논문지
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• 제6권11S호
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• pp.3340-3349
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• 1999

Supporting object group on distributed object system give merits such as load balancing, fault tolerance and high availability. In this paper, we describe a CORBA ORB that has been designed to support object group based on active replication. The ORB supports the operational model in which it uses the IIOP for communication between client and server and total ordered multicast protocol for consistency control among group members. And through extension of ORB, it provides functions required for support of object group. Since it provides transparency of object replication, the ORB is interoperable with the existing CORBA products. It make possible for existing server application to be easily extended to application supporting object group as adding interface functions which should be used for building applications is minimized. A prototype is implemented, and performance of the replicated object group is tested and compared with a single object invocation.

• 정보기술과데이타베이스저널
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• 제7권1호
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• pp.17-26
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• 2000

To provide highly available services in the distributed object system, it is required to support the object group. The state machine approach and primary-backup approach are proposed as two representative approaches for support of object group. The primary-backup approach does not only give merits such as transparency of object group and non-deterministic execution but also require less resource than state machine approach. This paper describes an extension of CORBA that is required to support of the primary-backup object group. In this paper, the state of backup is synchronized with primary through the atomic multicast protocol whenever the request of client is executed at primary. As a result, it does not require message logging and check pointing. The object group of this paper also provides fast response time in case of failure of the primary since it makes primary election unnecessary. And through an extension of IDL, it makes possible to avoid consistency control depending on characteristic of application. A prototype has been implemented and the performance of object group has been compared with a single object invocation.

• 한국전자거래학회지
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• 제4권1호
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• pp.145-157
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• 1999

The challenge is to maximize the time-to-market benefits of concurrent engineering while maintaining control of data and distributing it automatically to the people who need it when they need it. The way PDM systems cope with this challenge is that master data is held only once in a secure vault where its integrity can be assured and all changes to it monitored, controlled and recorded. The structure of PDM is various from vendor, but they have common module. That is PDM and it is most important. The goal is to design the workflow in PDM using object-oriented modeling method. The past methods have concentrated on the flow between workflow engine and agent, but this paper will focus on task. We will model task as individual object. This paper uses OMT(Object Modeling Technique) by James Rumbaugh for base modeling tool and uses DCOM(Distributed Component Object Model) for base ORB(Object Request Broker). Research object is to design the static object model, to design state change by dynamic model and to design data transition by functional model.

• 한국정보처리학회논문지
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• 제4권11호
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• pp.2721-2731
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• 1997

분산 프로그래밍은 분산 커뮤니케이션에 대한 언어적 지원을 기반으로 상당히 단순화 될 수 있다. 현재, 많은 웹 브라우저들은 다양한 형태의 액티브 객체들을 제공하고 있으며, 그 수와 유형은 빠른 속도의 증가 추세에 있다. 자바애플릿은 널리 알려진 웹 브라우저 관련 액티브 객체중의 하나이다. 이 논문은 인터넷 상에 분산되어 있으면서 서로 정보를 교환할 수 있는 분산 액티브 객체의 구현에 관하여 기술한다. 분산 액티브 객체를 구현함에 있어서, 접근방식이 다르고 상호 호환성이 결여된 주요한 두 프로그래밍 환경은 RMI와 CORBA IDL 방식이다. 분산 액티브 객체의 구현상 쟁점들을 명확하게 하기 위해서, RMI 메커니즘을 채택한 HORB와 CORBA를 채택한 OrbixWeb2.0.1 환경 하에서 하나의 어플리케이션 프로그램을 각각 구현하였다. 부산 객체 사이의 바인딩, 상속성. 다형성, 객체의 전달, 콜백은 구현상 중요한 쟁점들이었다. 실험결과는 분산 액티브 객체를 구현하는데 있어서 작은 차이가 분산 어플리케이션의 구성에 상당한 영향을 미칠 수 있음을 보여 주었다. 두 프로그래밍 환경 하에서 구현된 어플리케이션 간의 비교는 각각의 환경에서 구현된 어플리케이션 사이의 상호 변환 시스템을 구축하기 위한 기초 연구가 될 것이다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권5호
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• pp.1400-1420
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• 2012

Object detection and tracking using visual sensors is a critical component of surveillance systems, which presents many challenges. This paper addresses the enhancement of object detection and tracking via the combination of multiple visual sensors. The enhancement method we introduce compensates for missed object detection based on the partial detection of objects by multiple visual sensors. When one detects an object or more visual sensors, the detected object's local positions transformed into a global object position. Local and global information exchange allows a missed local object's position to recover. However, the exchange of the information may degrade the detection and tracking performance by incorrectly recovering the local object position, which propagated by false object detection. Furthermore, local object positions corresponding to an identical object can transformed into nonequivalent global object positions because of detection uncertainty such as shadows or other artifacts. We improved the performance by preventing the propagation of false object detection. In addition, we present an evaluation method for the final global object position. The proposed method analyzed and evaluated using case studies.