Integrated ship controlsystems can be designed as robust, distributed, autonomous controlsystems. The EU-funded ATOMOS I and ATOMOS II projects involve both technical and non-technical aspects of this process. Resul...
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Integrated ship controlsystems can be designed as robust, distributed, autonomous controlsystems. The EU-funded ATOMOS I and ATOMOS II projects involve both technical and non-technical aspects of this process. Results of the work includes: a reference modeling concept giving an outline of a generic ISC system covering the network and the equipment connected to it, a framework for the verification of network functionality and performance by simulation, and a general distribution platform for ISC systems as well as the ATOMOS network. (C) 1998 Elsevier Science Ltd. All rights reserved.
This paper proposes an extended TCP/IP protocol, LAN-TCP, that can be used for distributed soft real-time systems connected through an Ethernet-based local area network. Since LAN-TCP shows soft real-time performance,...
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This paper proposes an extended TCP/IP protocol, LAN-TCP, that can be used for distributed soft real-time systems connected through an Ethernet-based local area network. Since LAN-TCP shows soft real-time performance, while maintaining compatibility and interoperability with the standard TCP/IP, the existing application software can be used without any modification. LAN-TCP also provides a periodic transmission mode (PTM), with which periodic data collection and the updating of the control signals can be efficiently implemented with relatively small traffic overhead. This paper includes a computer simulation and experimental results for the proposed protocol. (C) 1998 Elsevier Science Ltd. All rights reserved.
This paper addresses the problem of delivering real-time messages, both periodic and aperiodic, over a Fibre Channel Arbitrated Loop or FC-AL. Periodic messages typically have hard real-time constraints, whereas aperi...
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This paper addresses the problem of delivering real-time messages, both periodic and aperiodic, over a Fibre Channel Arbitrated Loop or FC-AL. Periodic messages typically have hard real-time constraints, whereas aperiodic messages are delivered as soon as possible. The deadlines of periodic messages are guaranteed by limiting the packet size under the access fairness algorithm defined in FC-AL. The aperiodic messages are delivered using a global server scheme based on the full duplex communication and transfer state facilitated in FC-AL. The algorithm presented in this paper is optimal in that it fully utilizes network bandwidth, while guaranteeing the respective deadlines of periodic messages. (C) 1998 Elsevier Science Ltd. All rights reserved.
Real-Time systems must often handle several independent periodic macro-tasks, each one represented by a general tasks graph, including communications and precedence constraints. The implementation of such applications...
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ISBN:
(纸本)0818686464
Real-Time systems must often handle several independent periodic macro-tasks, each one represented by a general tasks graph, including communications and precedence constraints. The implementation of such applications on a distributed system communicating via a bus, requires tasks assignment and scheduling, as well as the taking into account of the communication delays. As periodicity implies macro-tasks deadlines, the problem of finding a feasible schedule is critical. This paper addresses this NP-hard problem resolution, by using a genetic algorithm, under offline and non-preemptive scheduling assumptions. This algorithm performances are evaluated on a large simulation set, and compared to classical list-bused algorithms, a simulated annealing algorithm and a specific clustering algorithm.
The DeSiDeRaTa project is producing technology to enable the engineering of the emerging generation of distributed real-time systems. Such systems have rigorous Quality of Service (QoS) objectives. They must behave in...
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The DeSiDeRaTa project is producing technology to enable the engineering of the emerging generation of distributed real-time systems. Such systems have rigorous Quality of Service (QoS) objectives. They must behave in a dependable manner, respond to threats in a timely fashion and provide continuous availability, even within hostile and unknown environments. To provide the desired QoS in such a context, the DeSiDeRaTa project focuses on QoS specification, dynamic QoS management middleware, and benchmarking of dynamic real-time systems. This paper discusses each of these aspects, and presents experimental results of applying DeSiDeRaTa technology to a dynamic realtime benchmark system.
Train Communication Network (TCN) standardized by IEC is designed for the railway applications, which addresses the real-time, availability and integrity requirements of the critical on-board train control functions. ...
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Train Communication Network (TCN) standardized by IEC is designed for the railway applications, which addresses the real-time, availability and integrity requirements of the critical on-board train control functions. It has a hierarchical structure consisting of Wired Train Bus (WTB) and Multi-function Vehicle Bus (MVB). These TCN buses provide two major services: real-time communication for time-critical process data and non-real-time but reliable communication for message data. This paper evaluates the performance of TCN applied to Korean High Speed Train(KHST). The evaluation results proposed in this paper can be used for adjusting the medium allocation and the scheduling schemes for TCN network.
Object-oriented models and multimedia user interfaces are of growing importance for modern distributed automation systems. An object-oriented communication system is introduced, based on an implementation of the CORBA...
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Object-oriented models and multimedia user interfaces are of growing importance for modern distributed automation systems. An object-oriented communication system is introduced, based on an implementation of the CORBA 2.0 standard, which is applicable to any distributed process control system in basic industries. The object concept allows user interface objects and automation objects to be integrated into one common model. Therefore the author is investigating and developing methods and utilities that provide an object-oriented integration of multimedia functions into distributed process controlsystems. A first prototype of the communication system allows a periodic exchange of still images between a supervising camera at one computer and a remote computer via a small-band ISDN telephone line.
This paper presents an extension of a real-time operating system for the implementation of robots control architectures. This software, called NEXUS, provides facilities for connecting and intercommunicating the compo...
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This paper presents an extension of a real-time operating system for the implementation of robots control architectures. This software, called NEXUS, provides facilities for connecting and intercommunicating the components of a robotic application. It is a distributed, robust and real-time framework. NEXUS consists of two subsystems: the Task-Dependent Subsystem that may vary from one architecture to another, and the Management Subsystem, that maintains the structural information about the architecture and supports the communications. NEXUS has been tested implementing a simple architecture for the RAM-2 mobile robot. It has demonstrated its robustness and its simple, well-defined interface for integrating diverse algorithms.
In this paper, we analyse the ability of Profibus fieldbus to cope with the real-time requirements of a distributedcomputercontrol System (DCCS), where messages associated to discrete events must be made available w...
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In this paper, we analyse the ability of Profibus fieldbus to cope with the real-time requirements of a distributedcomputercontrol System (DCCS), where messages associated to discrete events must be made available within a maximum bound time. Our methodology is based on the knowledge of real-time traffic characteristics, setting the network parameters in order to cope with timing requirements. Since non-real-time traffic characteristics are usually unknown at the design stage, we consider an operational profile where, constraining non-real-time traffic at the application level, we assure that realtime requirements are met.
Advanced information processing technologies are providing advanced controllers with capabilities to tackle control problems of intrinsic complexity. Methods to cope with the software-intensive control system developm...
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Advanced information processing technologies are providing advanced controllers with capabilities to tackle control problems of intrinsic complexity. Methods to cope with the software-intensive control system development are needed, because quality issues in control software are of extreme importance. Architecture based development provides a clear pathway to quality, focusing on component based control system development. In the case of intelligent controllers, advanced control modules (expert, fuzzy, neural, etc.) can be built to be reusable. In the ideal situation, application construction would be a matter of plugging in the controllers and then making a customization work of them.
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