• Journal of Institute of Control, Robotics and Systems
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• v.14 no.11
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• pp.1117-1123
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• 2008

This paper implements dual-kernel system using standard Linux and real-time embedded Linux for the real-time control of intelligent robot systems. Such system provides more useful services including standard Linux thread that is easy to implement complicated tasks and real-time tasks for the deterministic response to velocity control. Here, an open source real-time embedded Linux, XENOMAI, is ported on embedded target board. And for interfacing with motor controller we adopted a real-time serial device driver. The real-time task was implemented with a priority to keep the cyclic control command for trajectory control. In order to validate deterministic response of the proposed system, the performance measurement of the delay in performing trajectory control with feedback loop is evaluated with non real-time standard Linux. The proposed software architecture is anticipated to take advantage of features in both standard Linux and real-time operating systems for the intelligent robot systems.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.89-89
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• 2000

The Current CORBA has many drawbacks to be deployed successfully in real-time system applications. Recently, OMG adopted Real-Time CORBA specification. In this paper, we report our efforts on an implementation of Priority Model of Real-Time CORBA spec., which is one of the most important components in Real-Time CORBA spec. The improvement of real-time performances of our implementation is verified experiments.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.487-487
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• 2000

The scheduling of real-time tasks needs both correctness and timeliness. But it is not easy to schedule real-time tasks having different characteristics in a single system. In this paper we solve the problem through an approach using the performance evaluation of real-time tasks through fuzzy-random variables. Using the performance evaluation through fuzzy-random variable, we can achieve flexible and efficient scheduling for real-time systems.

• IEMEK Journal of Embedded Systems and Applications
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• v.10 no.4
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• pp.233-239
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• 2015

This paper describes a method that is integrated trace for real-time virtualization environment. This method has solved the problem that the performance trace may not be able to analyze integrated method between heterogeneous operating systems which is consists of real-time operating systems and general-purpose operating system. In order to solve this problem, we have attempted to reuse the performance analysis function in general-purpose operating system, thereby real-time operating systems can be analyzed along with general-operating system. Furthermore, we have implemented a prototype based on ARM Cortex-A15 dual-core processor. By using this integrated trace method, real-time system developers can be improved productivity and reliability of results on real-time virtualization environment.

• Journal of Institute of Control, Robotics and Systems
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• v.3 no.1
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• pp.77-88
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• 1997

Fieldbus is the lowest level communication network in factory automation and process control systems. Performance of factory automation and process control systems is directly affected by the data delay induced by network traffic. Data generated from several distributed field devices can be largely divided into three categories: sporadic real-time, periodic real-time and non real-time data. Since these data share one fieldbus network medium, the limited bandwidth of a fieldbus network must be appropriately allocated to the sporadic real-time, periodic real-time and non real-time traffic. This paper introduces a new fieldbus design scheme which allocates the limited bandwidth of fieldbus network to several different kinds of traffic. The design scheme introduced in this study not only satisfies the performance requirements of application systems interconnected into the fieldbus but also fully utilizes the network resources. The design scheme introduced in this study can be applicable to cyclic service protocols operated under single-service discipline. The bandwidth allocation scheme introduced in this study is verified using a discrete-event/continuous-time simulation experiment.

• Journal of the Korean Society of Systems Engineering
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• v.2 no.2
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• pp.21-26
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• 2006

In modern systems technology, increasingly more systems are anticipated to operate in real-time environment. These systems are usually complex to implement since it is not easy to satisfy the real-time requirement for both hardware and software components simultaneously. In this paper, we first review an object-oriented development process that was proposed earlier for software-intensive real-time system using the Unified Modeling Language (UML). We then study how to improve the problems that the UML approach might have. Applying the systems engineering(SE) process yields useful results which include : 1) an improved requirements management over the whole system life-cycle ; 2) a detailed scenario on how to carry out the SE process ; and 3) a conversion process from the text-based requirements to the UML-based graphic ones.

• Journal of the Korea Institute of Military Science and Technology
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• v.16 no.3
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• pp.260-267
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• 2013

A combat system for navy's battleship is a system of systems who supports naval indigenous operations by integrating and inter-operating many different kind of weapon and non-weapon systems, which has characteristics of large-scale complex computing system. This paper considers a characteristics of naval combat system which has been developed by domestic technology and suggests a way to improve future naval combat system in terms of computing architecture by applying commercial real-time operating system technologies. This paper also provides an evaluation criteria for combat system adaptability of real-time operating systems.

• Journal of Information Technology Services
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• v.16 no.3
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• pp.103-111
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• 2017

The real time scheduling is a key research area in high performance computing and has been a source of challenging problems. A periodic task is an infinite sequence of task instance where each job of a task comes in a regular period. The RMS (Rate Monotonic Scheduling) algorithm has the advantage of a strong theoretical foundation and holds out the promise of reducing the need for exhaustive testing of the scheduling. Many real-time systems built in the past based their scheduling on the Cyclic Executive Model because it produces predictable schedules which facilitate exhaustive testing. In this work we propose hybrid scheduling method which combines features of both of these scheduling algorithms. The original rate monotonic scheduling algorithm didn't consider the uniform sampling tasks in the real time systems. We have enumerated some issues when the RMS is applied to our hybrid scheduling method. We found the scheduling bound for the hard real-time systems which include the uniform sampling tasks. The suggested hybrid scheduling algorithm turns out to have some advantages from the point of view of the real time system designer, and is particularly useful in the context of large critical systems. Our algorithm can be useful for real time system designer who must guarantee the hard real time tasks.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.3
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• pp.318-325
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• 2008

In this paper, a dynamic backoff adjustment method of IEEE 802.15.4 is proposed for time-critical sporadic data in a noisy factory environment. For this, a superframe of IEEE 802.15.4 is applied to a real-time mixed data (periodic data, sporadic data, and non real-time message) transmission in factory communication systems. To guarantee a channel access of real-time sporadic(non-periodic) data, a transmission method using the dynamic backoff is applied to wireless control networks. For the real-time property, different initial BE, CW parameters are used for the dynamic backoff adjustment method. The simulat-ion results show an enhancement of the real-time performance of sporadic emergency data. The proposed method provides the channel access of real-time sporadic data efficiently, and guarantee real-time transmission simultaneously within a limite-d timeframe.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.7
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• pp.602-610
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• 2000

In communication networks used in safety-critical systems such as control systems in nuclear power plants there exist three types of data traffic : urgent or asynchronous hard real-time data hard real-time periodic data and soft real-time periodic data. it is necessary to allocate a suitable bandwidth to each data traffic in order to meet their real-time constraints. This paper proposes a method to meet the real-time constraints for the three types of data traffic simultaneously under a timer-controlled token bus protocol or the IEEE 802.4 token bus protocol and verifies the validity of the presented method by an example. This paper derives the proper region of the high priority token hold time and the target token rotation time for each station within which the real-time constraints for the three types of data traffic are met, Since the scheduling of the data traffic may reduce the possibility of the abrupt increase of the network load this paper proposes a brief heuristic method to make a scheduling table to satisfy their real-time constraints.