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Proceedings Seventh Euromicro Workshop on Real-Time Systems

14-16 June 1995

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  • Proceedings Seventh Euromicro Workshop on Real-Time Systems

    Publication Year: 1995
    Request permission for commercial reuse | PDF file iconPDF (195 KB)
    Freely Available from IEEE
  • HyperReal One: the implementation, the environment and an example

    Publication Year: 1995, Page(s):17 - 24
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (813 KB)

    HyperReal One (HR1) is an experimental platform for hard real time (HRT) systems which has been developed in the context of the HyperReal project. It is focused on the experimentation of architectural abstractions related to configuration and timing or deeply embedded applications. HR1 introduces actors and connectors as basic components, plus a set of components (virtual clocks, plans, controller... View full abstract»

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  • Architectural abstractions and time modelling in HyperReal

    Publication Year: 1995, Page(s):222 - 228
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (776 KB)

    This paper describes the foundation of the HyperReal project. It is centred on the definition of architectural abstractions that permit designing modular RT systems. Basic components are reactive agents manipulating data and connectors supporting interactions among agents. Such components are not aware of the system configuration nor of the control strategy, which are managed by a configurator and... View full abstract»

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  • One solution for the non-determinism problem in the SCEPTRE 2 fault tolerance technique

    Publication Year: 1995, Page(s):352 - 358
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (457 KB)

    SCEPTRE 2 is a normative report on the basic mechanisms of the real-time executive kernels. No fault tolerance technique exists in its current version. So, in order to develop fault tolerant real time applications, redundancy management service must be provided. In this paper we present the difficulties we have found during the implementation of fault tolerance in SCEPTRE 2. These difficulties are... View full abstract»

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  • Index of authors

    Publication Year: 1995
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    Freely Available from IEEE
  • A dedicated digital unit for event recognition and centroiding in photon counting intensified CCDs

    Publication Year: 1995, Page(s):71 - 78
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (536 KB)

    A dedicated digital electronic system for real time acquisition and processing of data arrays with input rate as high as 20 MHz is presented. The system identifies and determines the center coordinates, to sub-pixel accuracy of events produced by a photon counting intensified CCD. Each photon event is represented, on the CCD matrix, by a charge distribution of approximately Gaussian profile. Ident... View full abstract»

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  • Dynamic replacement of software in hard real-time systems: practical assessment

    Publication Year: 1995, Page(s):26 - 33
    Cited by:  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (580 KB)

    There are systems that cannot be stopped without losses. However, these systems require modifications during their operational life. Dynamic software replacement is a mechanism that allows components updating without stopping the whole system. The paper deals with dynamic replacement in hard real time systems. A protocol for dynamic replacement of software components in embedded hard real time sys... View full abstract»

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  • Fuzzy-control with a PEARL-based multi-loop controller

    Publication Year: 1995, Page(s):66 - 70
    Cited by:  Papers (1)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (424 KB)

    To serve the demand for fuzzy control components in automation systems, manufacturers extend the function block libraries of their multi loop and PLC software by respective function blocks. Other demands are for the openness of PLC software and its adaptation to the IEC 1131 standard which, for the first time, gives recommendations with respect to a task model and task communication. The unique id... View full abstract»

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  • Towards refinement in realtime programming

    Publication Year: 1995, Page(s):244 - 251
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (628 KB)

    The objective of the research presented is the development of an approach for developing real time programs by successive refinement of abstract specifications. It is based on the approach by C. Morgan (1994), which assures the correctness of non real time sequential programs on the basis of the `method of construction'. The consideration of time, however, makes the refinement a more complex task,... View full abstract»

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  • Hybrid specification and formal distributed heterogeneous prototyping of distributed real-time systems

    Publication Year: 1995, Page(s):191 - 196
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (548 KB)

    The Boehm spiral model is a generic risk-driven software development model. The design of low level risk elements is postponed until the high risk elements are stabilized. The Spiral model accommodates to rapid prototyping to solve various risk kinds. It also accommodates to incremental distributed heterogeneous prototyping to support concurrent engineering, which may be organized around subsystem... View full abstract»

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  • Simulation of real time scheduling at design levels

    Publication Year: 1995, Page(s):140 - 146
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (680 KB)

    Real time systems (RTS) development adds-at least-two complexity factors to the traditional development tasks: time and resource constraints, and differences between development and final architecture. They make the development cycle longer. The paper presents one use of the well known formalism called High Level Time Petri nets (HLTPN) applied to the design of RTS in the form of subnets that can ... View full abstract»

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  • Real-time recursive procedures

    Publication Year: 1995, Page(s):229 - 235
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (464 KB)

    The purpose of the paper is to show that recursive procedures can be used for implementing real time applications without harm, if a few conditions are met. These conditions ensure upper bounds for space and time requirements can be derived at compile time. Moreover they are simple enough such that many important recursive algorithms can be implemented, for example Mergesort or recursive tree trav... View full abstract»

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  • SIGNAL GTi: implementing task preemption and time intervals in the synchronous data flow language SIGNAL

    Publication Year: 1995, Page(s):176 - 183
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (668 KB)

    This paper presents SIGNAL GTi, the encoding and implementation of an extension to the reactive data flow language SIGNAL with constructs for hierarchical task preemption. Tasks are defined as the association of a data-flow process with a time interval on which it is executed. The motivation for introducing these preemption structures is the need for the specification of different modes of interac... View full abstract»

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  • MMS and time

    Publication Year: 1995, Page(s):124 - 131
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (704 KB)

    This paper addresses MMS and real time issues. The requirements for real time systems are introduced. The paper also presents briefly MAP, and in particular, the MMS standard in real time environments, emphasising its weaknesses and goes on to show our approach to making MMS more suitable for a real time context. The approach consists of modifying the existing objects, services and protocol to sat... View full abstract»

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  • A multi-agent distributed real-time system for a microprocessor field-bus network

    Publication Year: 1995, Page(s):302 - 307
    Cited by:  Papers (2)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (648 KB)

    A new conception of a multi agent distributed real time system (MAD-RTS) is presented, comprising compiler, operating system kernel and communication tools. It allows for a uniform programming of complex process control systems on a microprocessor field bus network. The key idea is to decompose the whole control task into small execution units, called agents which communicate by sending and execut... View full abstract»

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  • A Q-model approach to decomposition and aggregation of specifications of real-time systems

    Publication Year: 1995, Page(s):213 - 219
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (524 KB)

    New application areas and the increasing complexity of problems to be solved with real-time systems have led to a corresponding decrease in the probability of designing a correct solution. In this paper a Q-model approach to the problem of dealing with complexity of the specification process, specifically some aspects of decomposition and aggregation, is discussed. The evolutionary development of ... View full abstract»

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  • A distributed implementation of a mode switching control program

    Publication Year: 1995, Page(s):164 - 168
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (336 KB)

    A distributed implementation of a mode switched control program for a robot is described. The design of the control program is given by a set of real-time automatons. One of them plans a schedule for switching between a fixed set of control functions, another dispatches the control functions according to the schedule, and a final one monitors the system for exceptions that shall lead to a halt. Th... View full abstract»

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  • A performance study of several CSMA protocols for time constrained applications

    Publication Year: 1995, Page(s):108 - 115
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (472 KB)

    The paper compares the performance of several CSMA/CD protocols that can be easily implemented using the Intel microcontroller 83C152. These protocols are: CSMA/CD, CSMA/DCR and CSMA/CD with priorities. The behavior of these protocols was studied using typical workloads for time constrained applications that includes different kinds of data View full abstract»

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  • Scheduling complex real-time tasks in an embedded distributed system

    Publication Year: 1995, Page(s):62 - 65
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (328 KB)

    Most current real time scheduling algorithms allocate the processing unit independently of other resources. Some of them integrate processing unit and passive resource allocation to avoid deadlocks or data coherency failures, but the proposed mechanisms often rely on the access to shared control variables (e.g. semaphores) and have been mainly implemented in monoprocessor contexts. Moreover, they ... View full abstract»

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  • Meeting hard-real-time constraints using a client-server model of interaction

    Publication Year: 1995, Page(s):286 - 293
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (584 KB)

    The Ster environment integrates programming languages with scheduling strategies to support the development of flexible and predictable distributed systems. Ster application objects can establish a client-server relationship, and clients may specify sequences of services that should be treated as atomic multiservice accesses. The core of Ster's scheduling strategy is an offline scheduler that sear... View full abstract»

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  • Kernel services approach to fault-masking in real-time applications

    Publication Year: 1995, Page(s):336 - 343
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (656 KB)

    The N-Modular Redundancy (NMR) architecture has shown to perform fault-masking with acceptable cost and performance. The restriction to the majority voting imposed by many of its implementation models often discourages its use in real-time applications with sensors' data. Its implementation in real applications also exhibits time overhead, and synchronization problems beside the increase in hardwa... View full abstract»

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  • A layered architecture for real time applications

    Publication Year: 1995, Page(s):11 - 16
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (512 KB)

    The paper argues that real time control systems should be structured in abstraction layers in provide adequate instruction formalisms for both task specification and for low level control, and that the design information used when specifying the system should be included in the encoding of the abstraction barrier. When this design information is available, describing the semantics of the abstracti... View full abstract»

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  • Pessimistic Deadline Ceiling Protocol: a concurrency control protocol under earliest deadline first scheduling

    Publication Year: 1995, Page(s):80 - 86
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (540 KB)

    Priority inversion is one of the major sources which makes the real-time system unpredictable. The Stack Resource Policy (SRP) and the Dynamic Priority Ceiling Protocol (Dpcp) are two representative protocols that solve the priority inversion problem under earliest deadline first scheduling (EDF). Dpcp yields better performance but incurs more overhead than SRP. We propose a new algorithm called t... View full abstract»

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  • Measuring the real-time operating system performance

    Publication Year: 1995, Page(s):34 - 40
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (496 KB)

    Tests for measuring the real time operating system performance belong to the software technology. They give quantitative measures for the most important characteristics and allow the implementer to compare the efficiency of various operating systems. The paper presents a set of simple tests for measuring the real time operating system characteristics. The tests require no specialized hardware, and... View full abstract»

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  • Hybrid algorithms for dynamic schedulability testing

    Publication Year: 1995, Page(s):254 - 261
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (716 KB)

    The paper describes an investigation into the performance of a variety of algorithms for dynamic schedulability testing. A real time node may run its own set of resident periodic tasks and may also receive aperiodic requests for computations to be completed within hard deadlines. In order to decide whether each request is schedulable, and can therefore be accepted, the node may use a guarantee alg... View full abstract»

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