Proceedings Sixth Euromicro Workshop on Real-Time Systems

15-17 June 1994

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  • Proceedings Sixth Euromicro Workshop on Real-Time Systems

    Publication Year: 1994
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    Freely Available from IEEE
  • Animation in CONRAD: informal analysis of timing properties

    Publication Year: 1994, Page(s):220 - 225
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (404 KB)

    It is suggested that timing restrictions are the fundamental part of the specification of a time-critical system (limiting the possible design solution space), because most of the timing restrictions have been objectively determined by the object to be controlled and thus cannot be changed arbitrarily. Timing correctness in real-time systems means that process activations, data production and cons... View full abstract»

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  • Relating specified time tolerances to implementation performances

    Publication Year: 1994, Page(s):226 - 233
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (688 KB)

    Real-time systems require that the high-level control constructs used by the designer have a rigorously defined semantics specifying their actual temporal behavior, which unfortunately depends on implementation details that the high-level view tends to hide from the user. Moreover the real implementations only approximate the typical ideal properties; in some systems these approximations cannot be... View full abstract»

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  • Scheduling in a hard real-time system with shared resources

    Publication Year: 1994, Page(s):234 - 239
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (500 KB)

    Hard real-time systems are those systems in which correctness depends on logical results of the computations as well as the times at which these results are produced. In a real-time context, concurrency control protocols for shared resources (as databases) must not only maintain the consistency constraints but also satisfy timing requirements of transactions. So, several protocols have been propos... View full abstract»

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  • Simple and robust: fuzzy for antislip

    Publication Year: 1994, Page(s):240 - 245
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    The authors present the design of an intelligent control for industrial off road vehicles with hydrostatic power transmission to prevent wheel slippage. Timing and robustness were of particular interest. The authors employed a system of interconnected wheel processors, which house a two level local/global fuzzy control algorithm View full abstract»

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  • On-line sporadic task scheduling in hard real-time systems

    Publication Year: 1994, Page(s):186 - 191
    Cited by:  Papers (1)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (460 KB)

    We propose a set of scheduling procedures for dealing with the sporadic task scheduling in a dynamic periodic system. For this we mean a system in which periodic tasks change their parameters dynamically (at run-time), in an unpredictable way. So, the off-line periodic task set will be different from the current periodic task set. It means that the task schedulability tests in such systems have to... View full abstract»

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  • Determining the worst-case blocking sequences for distributed real-time programs

    Publication Year: 1994, Page(s):4 - 9
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (340 KB)

    For detecting timing errors in a distributed real-time program (distributed real-time debugging) it is essential to know all combinations of execution paths where a given path experiences a worst-case blocking time through communication (server calls) among the subprograms. In this paper we deal with the subproblem of blocking sequences of server call pairs between 2 paths. For determining their w... View full abstract»

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  • Object-based design of embedded software using real-time operating systems

    Publication Year: 1994, Page(s):194 - 198
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (320 KB)

    Embedded systems are used in everyday electronic consumer products and industrial equipment, e.g. television sets, radios, cars, and mobile phones. Rapid developments which have taken place in computer hardware and software technologies have led to the increased complexity of embedded systems. Promising results have been achieved in the development of complex information processing systems using o... View full abstract»

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  • Application objects and modularity in real time graphical modelling

    Publication Year: 1994, Page(s):10 - 15
    Cited by:  Papers (2)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (348 KB)

    LACATRE is a graphical language intended to help in the design of applications requiring the use of multitasking real time executives. Within the software life cycle, LACATRE covers both preliminary and detailed design. After a brief description of the LACATRE basic objects, this paper presents the use of the application objects (or high level objects) such as agency and process, associated to the... View full abstract»

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  • Supporting real-time update of an environment representation for autonomous mobile robots

    Publication Year: 1994, Page(s):34 - 39
    Cited by:  Papers (1)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (440 KB)

    A model of the environment is a mandatory requirement for the autonomy of a mobile robot. As the environment may change over time, methods are necessary to update the model information, keeping pace with the sensor frame rate. Our approach to cope with this real time problem is to predict virtual sensor images, which are then compared against the real perceptions. Two alternative methods are detai... View full abstract»

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  • Guaranteed deadlines with dynamic recovery blocks in distributed systems

    Publication Year: 1994, Page(s):199 - 204
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (468 KB)

    In a hard real-time system, a timing fault is said to occur when a real time task delivers its results too late. An deadline mechanism has been proposed to avoid timing faults in uniprocessor machines. Under this approach, every task is implemented with two algorithms: on one hand, a primary program produces a good quality service but in an unknown and possibly infinite length of time due to softw... View full abstract»

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  • Modular specification of real-time systems

    Publication Year: 1994, Page(s):16 - 21
    Cited by:  Papers (1)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (348 KB)

    Duration Calculus, a real-time interval logic, has been embedded in the Z specification language to provide a notation for real-time systems that combines the modularisation and abstraction facilities of Z with a logic suitable for reasoning about real-time properties. In this article the notation is presented through a top-level specification of requirements for a simple air traffic monitoring sy... View full abstract»

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  • Enhancing real-time object-oriented analysis methods

    Publication Year: 1994, Page(s):104 - 109
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (488 KB)

    Discusses the application of object-oriented concepts to the development of real-time systems, focusing mainly on the requirements engineering phase. Shortcomings of existing real-time specification methods are identified. A proposal to overcome these shortcomings is presented. Our approach enhances existing object-oriented analysis (OOA) methods concerning a high-level description and consistency... View full abstract»

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  • The modular multimicroprocessor system architecture for the power turbine control

    Publication Year: 1994, Page(s):124 - 127
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (288 KB)

    The modular multimicroprocessor control system (MMCS) architecture for turbine control is presented. The turbine features which are produced by “Metalicheskiy Zavod” plc (St.-Petersburg) are considered. The multilayered MMCS system organization for these turbines is described. The architecture of distributed modular multimicroprocessor control system (MMCS) for turbo-unit technological... View full abstract»

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  • Realtime-learning on an autonomous mobile robot with neural networks

    Publication Year: 1994, Page(s):40 - 44
    Cited by:  Papers (3)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (360 KB)

    We discuss the usage of neural network clustering techniques on a mobile robot, in order to build qualitative topologic environment maps. This has to be done in realtime, i.e. the internal world-model has to be adapted by the flow of sensor-samples without the possibility to stop this data flow. Our experiments are done in a simulation environment as well as on a robot, called ALICE View full abstract»

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  • Algorithms for scheduling computations with secondary deadlines to minimize penalty

    Publication Year: 1994, Page(s):143 - 148
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (464 KB)

    In many real-time applications, some job allows part of its computation to be executed after its primary deadline but before an extended, or secondary deadline. We study the scheduling issues for real-time computations with secondary deadlines. We call the part of a computation which must be completed before the primary deadline its hard part, and the rest its soft part. The soft part of a computa... View full abstract»

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  • Formal specification and verification of a real-time kernel

    Publication Year: 1994, Page(s):205 - 211
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (412 KB)

    The paper presents a case study of application of the VDM formal method to specification and verification of a simple real-time kernel. Specifications of selected external services of the kernel are presented. Then the verification methodology is introduced by demonstrating its basic steps in relation to verification of a selected function-a process waiting for a signal on a condition variable. Th... View full abstract»

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  • Integration of RTL and precedence graphs with a static scheduler as verifier

    Publication Year: 1994, Page(s):22 - 25
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (300 KB)

    We present an approach to specification and verification of distributed hard real-time systems. By integrating RTL and precedence constraints, we combine the comprehensiveness of precedence graphs with the expressive power and proofability of RTL. Thus, our approach allows easy comprehension by the human designer and formal correctness. We propose to use a static scheduling algorithm based on heur... View full abstract»

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  • Implementing real-time applications with concurrent objects

    Publication Year: 1994, Page(s):92 - 97
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (444 KB)

    Presents a novel extension to the C++ programming language, allowing powerful expression of concurrency and synchronization in an object-oriented environment. The principal advantages of this extension over existing alternatives are its powerful, yet simple expression, its ease of use, and the strict parsimony of additions made to the C++ syntax. The concurrent and object-oriented capabilities of ... View full abstract»

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  • A software architecture for complex real-time systems

    Publication Year: 1994, Page(s):110 - 115
    Cited by:  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (484 KB)

    The increasing use of computer-based control systems in complex applications requires modelling techniques which make it easier to develop and maintain these systems. One promising approach is to use object-orientation. The difficulty is that a traditional object-oriented programming language is most suitable for use in small projects and therefore is not directly scalable to a heterogeneous and d... View full abstract»

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  • A dynamic scheduling algorithm for semi-hard real-time environments

    Publication Year: 1994, Page(s):130 - 137
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (620 KB)

    In many real-time systems, it is crucial for the application tasks to meet their specified deadlines, otherwise the tasks cause catastrophic results. Every task is generally periodic, and the value of its period depends on the dynamics of the process it controls. In addition, some additional time-critical tasks said to be sporadic can occur and require to be processed at unpredictable times. The p... View full abstract»

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  • Clock synchronization in virtual rings

    Publication Year: 1994, Page(s):72 - 77
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (488 KB)

    A probabilistic algorithm for external clock synchronization is proposed. The algorithm works under the assumption that it is possible to identify a virtual ring among the servers involved, and does not require an upper bound to message transmission delays. The approach is probabilistic, since clock synchronization is not guaranteed, but the probability of success can be made arbitrarily close to ... View full abstract»

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  • Modeling and scheduling real-time control systems with relative consistency constraints

    Publication Year: 1994, Page(s):46 - 52
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (504 KB)

    Control applications control and monitor an external physical environment. Process control and manufacturing systems are examples of such applications. In such systems the temporal relationship between the external environment and the control system plays an important role. In this paper, the temporal relationship of data within the control system and the external environment, known as data tempor... View full abstract»

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  • On using epsilon serializable locking protocol for concurrency control in real-time databases

    Publication Year: 1994, Page(s):150 - 155
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (388 KB)

    New non-serializable protocols based on incorporating epsilon serializability (ESR) into the real-time concurrency control protocol, Hybrid Two Phase Locking (Hb2PL) are proposed. The protocols try to maximize the values of the transactions by making a compromise between meeting transaction deadlines and maintaining consistent transaction view. Two different ways of incorporating ESR into Hb2PL ar... View full abstract»

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  • Timing analysis and conditional scheduling in a real-time system design environment

    Publication Year: 1994, Page(s):214 - 219
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (524 KB)

    This paper presents an approach to carry out timing analysis and scheduling in a real-time system design environment for flexible manufacturing systems. It is built based on a formal model for specifying real-time systems using extended timed Petri nets. The designer uses the model to specify a design at a given level. The functional characteristics as well as timing properties of the design can t... View full abstract»

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