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
  • 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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  • 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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  • 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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  • Using ObjectCharts to specify and design electronic systems

    Publication Year: 1995, Page(s):169 - 174
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (448 KB)

    A novel object-oriented description formalism is described which covers both time-discrete and time-continuous behavior. It can be used to describe hardware/software systems on various levels of abstraction. Allowing users to model their own virtual machine supports development on several abstraction levels at the same time. So different implementation configurations can easily be considered and a... View full abstract»

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  • A synchronous real-time knowledge-based system

    Publication Year: 1995, Page(s):205 - 212
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (708 KB)

    We propose a framework for the construction of real-time knowledge-based systems, under the production system paradigm and following the synchronous approach. This approach assumes that the inputs and outputs of a system are synchronous events, i.e. zero-time reaction systems. The proposed formalism which is used in this paper is based on a paraconsistent prepositional temporal logic, extended by ... View full abstract»

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  • An integrated technique for developing real-time systems

    Publication Year: 1995, Page(s):236 - 243
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (616 KB)

    The integration of conceptual modeling techniques, formal specification, and compositional verification is considered for real time systems within the knowledge engineering context. We define constructive transformations from a conceptual meta model to a real time specification language and give rules for compositional refinement steps. The ideas are illustrated by the design of a mine pump contro... View full abstract»

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  • Stochastic Petri net evaluation techniques in plant automation: tuning performance indices for distributed applications

    Publication Year: 1995, Page(s):294 - 301
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (748 KB)

    We report the results of an investigation aiming at experimenting the use of Generalized Stochastic Petri Nets (GSPN), a formal method which allows to model a concurrent application with an explicit representation of timing constraints, and to evaluate its performance over a target parallel architecture. We focus on the definition and use of a set of indices suitable to characterise an application... View full abstract»

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  • A layered architecture for real time applications

    Publication Year: 1995, Page(s):11 - 16
    Cited by:  Papers (1)
    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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  • 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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  • 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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  • 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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  • 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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  • Transforming designs towards implementations

    Publication Year: 1995, Page(s):197 - 204
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (668 KB)

    We are interested in constructing safety-critical systems from their requirements specification. Our approach is the following: we start with requirements formalized in Duration Calculus (DC). These requirements are transformed to another form in DC, expressing the design of the system. The design is then transformed to a joint action system expressed in DisCo language. The specifications in DC em... 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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  • StarBase: a firm real-time database manager for time-critical applications

    Publication Year: 1995, Page(s):317 - 322
    Cited by:  Papers (1)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (532 KB)

    Previous work in real-time database management systems (RT-DBMS) has primarily focused on simulation. This paper discusses how current real-time technology has been applied to architect an actual RT-DBMS on a real-time microlevel operating system. A real RT-DBMS must confront many practical issues which simulations typically ignore: race conditions, concurrency, and asynchrony. The challenge of co... View full abstract»

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  • Increasing schedulability in distributed hard real-time systems

    Publication Year: 1995, Page(s):99 - 106
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (900 KB)

    We present a study of the effects caused in distributed real time systems by jitter in the activation of tasks and messages. We show that although jitter has usually a small impact on the schedulability of single processor systems, in distributed architectures the worst case response times are significantly delayed. Reducing or eliminating jitter in these systems can increase the schedulability of... 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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  • A scheduling problem language

    Publication Year: 1995, Page(s):57 - 61
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (376 KB)

    A language for specification of the details of a scheduling problem is presented. First experiments indicate that the language can be used to express actual scheduling problems. Some deficiencies were detected but they can be fixed while keeping the general structure of the language View full abstract»

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  • MicroFaultTolerant (μFT)-a system for achieving cost effective fault tolerance in microcontroller based equipment

    Publication Year: 1995, Page(s):344 - 351
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (624 KB)

    MicroFaultTolerant (μFT) is a method for designing and implementing microcontroller based equipment which interacts with its environment and has a risk connected to its operation thus making fault-tolerance and fail-to-safe properties necessary. We are especially concerned about systems where the “safe” states change at non-deterministic intervals with describing values changing con... View full abstract»

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  • Property decomposition to speed up analysis

    Publication Year: 1995, Page(s):147 - 154
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (988 KB)

    The complexity and criticity of many real time systems suggest that the temporal reachability analysis technique can find a role in the industrial development of such systems. Unfortunately, the costs of time reachability analysis inhibits the systematic application of this kind of analysis in the early stages of development, when long verification sessions slow down the development process. Moreo... View full abstract»

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