• The Journal of Engineering Research
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• v.2 no.1
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• pp.73-82
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• 1997

In this paper, we examine design trends in the development of distributed real-time system. Many real-time systems developed over the last ten years share common characteristics including use of communications, imprecise computations, the object-oriented paradigm, multiprocessor node hardware, dynamic time-driven scheduling and the inclusion of fault tolerance mechanisms. By examining the major design decisions made in previous systems, the best attributes of these systems can be coalesced together to form the "ideal" real-time system. This paper examines such a system and the advantages and disadvantages of the design decisions involved.

• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.17-21
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• 1989

6-DOE simulator system is designed to real-time processing for motion control, data acquisition, image generation and image processing etc.. In this paper, we introduce hardware and software design technologies for distributed processing, event-trapping, system monitoring and time scheduling procedure in 6-DOF simulator system design.

• Journal of KIISE:Computer Systems and Theory
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• v.31 no.8
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• pp.432-444
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• 2004

In this paper, we construct the TMO-based object group model on distributed environment, and analyze and evaluate the executability for distributed real-time service of our object group model by developing the distributed real-time application simulator applying the model. The Time-triggered Message-triggered Object(TMO) is a real-time server object having real-time property itself. The TMO-based object group is defined as a set of objects which logically reconfigured the physically distributed one or more TMOs on network by a given distributed application. For supporting group management of the server objects, the TMO-based object group we suggested provides the functions which register and withdraw the solver objects as a group member to an arbitrary object group, and also provides the functions which insert and delete the access rights of server objects from clients. Also, our model was designed and implemented to support the appropriate object selection and dynamic binding service for a single TMO as well as the duplicated TMOs, and to support the real-time scheduling service for the clients which are requesting the service. Finally, we developed the Defence System against Invading Enemy Planes(DSIEP) simulator as a practical example of distributed real-time application by applying our model, and evaluated the adaptability of distributed service strategies for the group components and the executability of real-time services that the TMO-based object group model provides.

• Proceedings of the KIEE Conference
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• 2006.10c
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• pp.151-153
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• 2006

When distributed powers are interconnected to the grid, lack of source stability may cause some events that should be measured and stored as soon as they occur. This paper presents a real-time hardware system that has been developed for quick and reliable monitoring of the distributed powers quality. The system is composed of a digital signal processor (MPC7410, Motorola) and a 16 bits A/D board (VMIVME3122, GE). To guarantee the real time operation, it is based on a real time OS (VxWorks). Hardware tests of the embedded system have been made to check the performances of the proposed system. Test signals of several events are generated by using a LabView (hardware) system. The tests show that the system complies with the desired IEEE standard for power quality monitoring.

• Journal of the Korea Society of Computer and Information
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• v.21 no.12
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• pp.115-124
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• 2016

In this paper, a method to generate the extended model automatically on the critical elements in enterprise system based real time distributed architecture as well as the platform specific model(PSM) for Microsoft(MS) .NET platform is proposed. The key ideas of this method are real time distributed architecture should performed with satisfying strict constraints on life cycle of object and response time such as synchronization, transaction and so on, and .NET platform is able to implement functionalities including before mentioned by only specifying Attribute Code and maximizing advantages of MDA. In order to realize the ideas, functionalities which should be considered enterprise system development are specified and these are to be defined in Meta Model and extended UML profile. In addition, after definition of UML profile for .NET specification, by developing and applying these into plug-in of open source MDA tool, and extended models are generated automatically through this tool. Accordingly, by using proposed specification technology, the profile and tools easily and quickly reusable extended model can be generated even though low level of detailed information for functionalities which is considered in .NET platform and real time distributed architecture. In addition, because proposed profile is MOF which is basis of standard extended and applied, UML and MDA tools which observed MOF is reusable.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.10
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• pp.911-917
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• 2000

As many sensors and actuators are used in various automated systems, the application of network to real-time distributed control system is gaining acceptance in many industries. In order to take advantages of networking, however, the network should be carefully designed to satisfy real-time distributed control. This paper presents an implementation method of closed-loop control using Profibus-FMS. In order to implement a closed-loop control system, we used industrial computers with Profibus-FMS network cards and a DC servo motor. Through various experiments, the step response of the control system with network was compared with the reference response without network.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.5
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• pp.114-120
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• 2002

In a distributed real-time control system, it is essential to confirm the timing behavior of all tasks because these tasks of each real-time controller have to finish their processes within the specified time intervals called a deadline. In order to satisfy this objective, the timing analysis of a distributed real-time system such as shcedulability test must be performed during the system design phase. In this study, a simple application of CAN fur a vehicle body network system is formulated to apply to a holistic scheduling analysis, and the worst-case execution time (WCET) and the worst-case end-to-end response time (WCRT) are evaluated in the point of holistic system view.

• Proceedings of the KIEE Conference
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• 2004.05a
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• pp.59-61
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• 2004

Researches about scheduling distributed real-time systems have some weak points, not scheduling both sporadic and periodic tasks and messages or being unable to guaranteeing the end-to-end constraints due to omitting precedence relations between sporadic tasks. This paper describes the application model of sporadic tasks with precedence constraints in a distributed real-time system. It is shown that existing scheduling methods such as Rate Monotonic scheduling are not proper to be applied to the system having sporadic tasks with precedence constraints. So this paper proposes an end-to-end laxity-based priority assignment algorithm which considers the practical laxity of a task and allocates a proper priority to a task.

• Journal of IKEEE
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• v.19 no.3
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• pp.357-365
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• 2015

Recently, embedded systems such as aircraft and automobilie, are developed as modular architecture instead of federated architecture because of SWaP(Size, Weight and Power) issues. In addition, partition operating system that support multiple logical node based on partition concept were recently appeared. Distributed recovery block is fault tolerance design scheme that applicable to mission critical real-time system to support real-time take over via real-time synchronization between participated nodes. Because of real-time synchronization, single-core based computer is not suitable for partition based distributed recovery block design scheme. Multi-core and AMP(Asymmetric Multi-Processing) based partition architecture is required to apply distributed recovery block design scheme. In this paper, we proposed design scheme of distributed recovery block on the multi-core based supervised-AMP architecture partition operating system. This paper implements flight control simulator for avionics to check feasibility of our design scheme.

• ETRI Journal
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• v.28 no.1
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• pp.31-44
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• 2006

In a packet switching network, congestion is unavoidable and affects the quality of real-time traffic with such problems as delay and packet loss. Packet fair queuing (PFQ) algorithms are well-known solutions for quality-of-service (QoS) guarantee by packet scheduling. Our approach is different from previous algorithms in that it uses hardware time achieved by sampling a counter triggered by a periodic clock signal. This clock signal can be provided to all the modules of a routing system to get synchronization. In this architecture, a variant of the PFQ algorithm, called digitized delay queuing (DDQ), can be distributed on many line interface modules. We derive the delay bounds in a single processor system and in a distributed architecture. The definition of traffic contribution improves the simplicity of the mathematical models. The effect of different time between modules in a distributed architecture is the key idea for understanding the delay behavior of a routing system. The number of bins required for the DDQ algorithm is also derived to make the system configuration clear. The analytical models developed in this paper form the basis of improvement and application to a combined input and output queuing (CIOQ) router architecture for a higher speed QoS network.