• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 ITC-CSCC -2
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• pp.723-726
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• 2000

In this paper, we present an abstract object-oriented plat-form model .suitable for the real-time distributed telecommunication system. The proposed platform is constructed upon the extended version of the real-time, distributed operating system, SROS(Scalable Real-time Operating System), that is developed at ETRI and successfully operated in the ATM switching system for several years. The object-oriented software development and maintenance methodology will resolve the current software crisis in the area of telecommunication and switching systems due to the everlasting maintenance about the huge amount of the existing software and the ever increasing needs for the better and new communication services. In general, an object-oriented software platform realizes the object-oriented methodology and possesses many good aspects like high productivity, better reusability, easy maintenance, et at. The platform is also designed to present the distributed multimedia service in addition to real-time event delivery. Recently, we have been implementing a couple of prototype bated on the proposed platform. Reflecting the evaluation results from these prototypes, the final platform specification will be determined.

• 한국국방경영분석학회지
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• 제25권1호
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• pp.199-214
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• 1999

The Constructive Battle Simulation Model is very important to the recent military training for the substitution of the field training. However, real battlefield systems operate under real-time conditions, they are inherently distributed, concurrent and dynamic. In order to reflect these properties by the computer-based simulation systems which represent real world processes, we have been developing constructive simulation model for several years. Conventionally, scheduling and resource allocation activities which have timing constraints, we elaborated on these issues and developed the simulation system on commercially available hardware and operating system with lock-free resource allocation scheme and rate monotonic scheduling.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -3
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• pp.1752-1755
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• 2002

The world wide web (WWW) already accounts f3r more Internee network traffic than any other application, including il and simple file transfer. It is also a collaborative technology in a weak sense of the word - it allows people to share information. Synchronous collaboration is where an interactive activity is simultaneous and in teal-time. Computer based real time collaborative systems like shared whiteboards. collaborative editor etc. are only beginning to emerge recently. These applications invoking more than two users exchanging information, require Multicast communication. Multicast communication is a transmission mode that is now supported by a variety of local and wide area networks. Multicasting enables multiparty communication across a wide area to sparsely distributed groups by minimizing the network load. Multicasting itself is one of the key technologies in the nut generation of the Internet This paper describes the technical issues from the aspect of multicast communication and its reliability in synchronous collaborative application.

• International Journal of Internet, Broadcasting and Communication
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• 제8권1호
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• pp.64-68
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• 2016

These fields are integrated to visualize and finalize the proposed development, in simulation environment. SCADA (supervisory control and data acquisition) systems and distributed control systems (DCSs) are widely deployed in all over the world, which are designed to control the industrial infrastructures, in real ways. To supervise and control the various parts of designed systems; trends to require a deep knowledge to understand the overall functional needs of industries, which could be a big challenge. Industrial field devices (or network sensors) are usually distributed in many locations and are controlled from centralized site (or main control center); the communication provides various signs of security issues. To handle these issues, the research contribution will twofold: a method using cryptography is deployed in critical systems for security purposes and overall transmission is controlled from main controller site. At controller site, multimedia components are employed to control the overall transmission graphically, such as system communication, bytes flows, security embedded parameters and others, by the means of multimedia technology.

• Journal of Electrical Engineering and Technology
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• 제8권4호
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• pp.712-718
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• 2013

With the development of industry and the improvement of living standards, better quality in power electric service is required more than ever before. This paper deals with the optimal algorithms for voltage regulation in the case where Distributed Storage and Generation (DSG) systems are operated in distribution systems. It is very difficult to handle the interconnection issues for proper voltage managements, because the randomness of the load variations and the irregular operation of DSG should be considered. This paper proposes the optimal on-line real time voltage regulation methods in power distribution systems interconnected with the DSG systems. In order to deliver suitable voltage to as many customers as possible, the optimal sending voltage should be decided by the effective voltage regulation method by using artificial neural networks to consider the rapid load variation and random operation characteristics of DSG systems. The simulation results from a case study show that the proposed method can be a practical tool for the voltage regulation in distribution systems including many DSG systems.

• 제어로봇시스템학회논문지
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• 제10권2호
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• pp.197-203
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• 2004

A real-time network in a distributed control system plays an important role for the reliable data transmission. Compared to the field-buses used in the past, TCP/IP protocol on the top of Ethered provides a compatibility between applications as well as an economical method to develop softwares. This paper proposes a modified TCP/IP structure for IEEE-1394 network, with which asynchronous and isochronous data transmission is selectively used for the real-time data transmission in a distributed control system. This paper also shows the performance of the proposed protocol by experiments.

• 스마트미디어저널
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• 제12권11호
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• pp.145-153
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• 2023

피어들의 접속과 이탈이 빈번한 P2P 기반의 분산 저장 시스템에서 실시간 제약 조건을 가지는 비디오 파일에 대해 데이터 가용성뿐만 아니라 재생 시 로컬 저장 장치에서 제공하는 수준의 품질을 보장하는 것이 필수적이다. 또한, 분산 저장 시스템 기반의 클라우드 저장 서비스에서는 각 사용자가 자신의 파일을 다른 사용자와 공유하는 기능을 제공하기 때문에 여러 사용자가 동일한 비디오 파일에 대해 동시에 재생을 요청하는 경우 모든 재생이 실시간으로 끊김 없이 지원되어야 한다. 따라서, 본 논문에서는 파일 공유를 지원하는 P2P 기반의 분산 저장 시스템에서 데이터 가용성뿐만 아니라 각 비디오 파일에 대해 동시에 요청되는 여러 재생들을 실시간 처리할 수 있는 기법을 제안한다. 이 기법은 각 비디오 파일에 대한 사용자의 재생 요청 수에 맞게 이레이져 코딩으로 인코딩된 중복 데이터의 양을 조절하여 실시간 동시 재생을 지원할 수 있으며 저장 공간을 효율적으로 사용할 수 있다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 A
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• pp.311-314
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• 2003

In recent years, distributed control systems(DCS) using fieldbus such as CAN have been applied to process systems but it is very difficult to design the DCS while guaranteeing the given end-to-end constraints such as precedence constraints, time constraints, and periods and priorities of tasks and messages. This paper presents a scheduling method to guarantee the given end-to-end constraints considering aperiodic, periodic and non-real-time message and task simultaneously. The presented scheduling method is the integrated one considering both tasks executed in each node and messages transmitted via the network and is designed to be applied to a general DCS that has multiple loops with several types of constraints, where each loop consists of sensor nodes with multiple sensors, actuator nodes with multiple actuators and controller nodes with multiple tasks.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제7권6호
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• pp.602-613
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• 2001

최근의 컴퓨팅은 이질적인 클라이언트와 서버들간의 상호 운용성을 요구하는 분산 어플리케이션을 위한 프로그래밍 파라다임을 지원하기 위한 분산 객체 컴퓨팅 환경으로 발전되고 있다. 여기에는 복잡한 네트워킹과 다양한 멀티미디어 응용 서비스를 위한 객체지향 기술들이 접목되고 있다. 이러한 분산 컴퓨팅 환경에서 처리되는 어플리케이션들의 실시간 서비스 지원을 위해 요구되는 실시간 특성과 분산 객체들의 관리의 어려움을 해결하기 위하여 본 논문에서는 실시간 객체그룹 플랫폼을 구축한다. 기존의 연구들은 실시간 CORBA를 사용하거나 또는 ORB를 수정하거나 실시간 운영체제상에 특정 CORBA 제품군을 사용하여 분산 환경의 특정 영역의 성능향상만을 도모하고 있다. 그러므로, 본 논문은 ORB의 수정 없이 표준 CORBA 상에서 실시간 특성을 지원할 수 있는 실시간 객체그룹 플랫폼을 설계한다. 본 논문의 실시간 객체그룹 구조는 객체들의 관리적인 측면과 실시간 어플리케이션 서비스 지원 측면에 대한 요구사항들을 분석하여 정립한 모델이며, 구성요소들의 기능을 관리와 서비스로 분리하여 각각의 기능 수행시에 발생하는 객체간의 상호작용이 다른 역할에 영향을 미치지 않도록 한다. 또한 구축된 플랫폼은 실시간 어플리케이션 개발자에게 실시간 특성 파라미터의 표현화 처리에 대한 투명성을 부여하여 어플리케이션에 유연성과 확장성을 제공하기가 용이하도록 한다. 따라서, 본 논문은 실시간 객체그룹 플랫폼의 구성요소들에 대한 역할을 정의하고 기능을 정립하며, 각 구성요소들을 설계하고 구현하였으며, 구현되어진 실시간 객체그룹 플랫폼의 기능과 수행 성능을 검증한다.

• 상하수도학회지
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• 제27권6호
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• pp.711-721
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• 2013

Optimal operation of a combined sewer network with distributed storage facilities aims to use the whole retention capacity of all reservoirs efficiently before overflows take place somewhere in the considered network system. An efficient real-time network control (RTNC) strategy has been emerging as an attractive approach for reducing substantially the overflows from a sewer network compared to the conventional fixed or manually adjusted gate setting method, but the related concrete framework for RTC development has not been throughly introduced so far. The main goal of this study is to give a detailed description of the RTNC systems via reviewing several guidelines published abroad, and finally to suggest methods for the proper application of RTNC on distributed storage facilities. Especially, this study is focused on emphasizing the importance of hierarchical structure of RTNC system that consists of three control layers (management, global control and local control). Further, with regard to the global control layer which is responsible for the central overall network control, the wide-ranging details of two components (adaption and optimization layers) are also presented. This study can provide the valuable basis for the RTNC implementation in the particular sewer network with distributed multiple storage facilities.