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
    Request permission for commercial reuse | PDF file iconPDF (16 KB)
    Freely Available from IEEE
  • 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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  • 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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  • 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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  • 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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  • 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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  • 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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  • 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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  • The sequencing of data flow tasks in SIGNAL: application to active vision in robotics

    Publication Year: 1994, Page(s):80 - 85
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (476 KB)

    Many applications of real-time systems feature a combination of “continuous” (possibly sampled) and discrete (sequencing and task control) behaviors, both reactive to the evolutions of the execution environment. In particular, robotics applications involve the programming of the control functions for each task, and the sequencing of such tasks at a higher level. In the framework of the... View full abstract»

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  • UltraSMART: a scalable multiprocessor architecture for real time

    Publication Year: 1994, Page(s):118 - 123
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (532 KB)

    Concurrent Computer Corporation's UltraSMART (scalable multiprocessor architecture for real time) architecture is a busless distributed shared memory multiprocessor architecture that enables higher levels of performance and better real-time behavior than can be obtained with bus-based global shared memory multiprocessors. The paper describes UltraSMART, the UltraSMART-based MAXION multiprocessor s... 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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  • Scheduling in a hard real-time system with shared resources

    Publication Year: 1994, Page(s):234 - 239
    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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  • Object-oriented enhancement of real-time software using a heterogeneous re-engineering approach

    Publication Year: 1994, Page(s):98 - 103
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (460 KB)

    A technique for incremental modernisation and enhancement of an existing procedural real-time software to an object-oriented one is presented. The incremental enhancement enables the real-time system designer to make use of the advantages of object-oriented paradigm: the resulting re-engineered software is more maintainable, reusable and configurable. In this approach, the object structure and add... 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 (2)
    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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  • 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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  • Can production systems be applied to hard real-time applications?

    Publication Year: 1994, Page(s):167 - 172
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (396 KB)

    Efficient match algorithms have influenced the acceptance of production systems in the industrial world. However, in embedded control systems they have not been applied intensively because of their non-deterministic run-time behavior. Until recently no method was known yielding rigorous upper bounds for run-time on match algorithms. Although the already published MLR (Micro Level Reasoner) method ... 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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  • 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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  • On-line sporadic task scheduling in hard real-time systems

    Publication Year: 1994, Page(s):186 - 191
    Cited by:  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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  • A resynchronization method for real-time supervision

    Publication Year: 1994, Page(s):66 - 71
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (536 KB)

    Real-time supervision is one technique used to improve the perceived reliability of software systems. A real-time supervisor observes the inputs and outputs of the system and reports failures that occur. The approach presented in this paper uses the specification of external behavior of the system to detect failures. Failures are reported in real-time. In addition, the approach permits the assessm... View full abstract»

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  • Animation in CONRAD: informal analysis of timing properties

    Publication Year: 1994, Page(s):220 - 225
    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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  • A software architecture for telerobotics

    Publication Year: 1994, Page(s):86 - 90
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (280 KB)

    Describes a currently developed software architecture for telerobotics, based on a high-level and interpreted language, PILOT (Programming and Interpreted Language Of actions for Telerobotics), allowing one to plan the actions of a robot. Such a language allows the operator to modify a mission during its execution. A software architecture is developed for this language, and is composed of four mod... 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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  • Dynamic scheduling for mobile robots

    Publication Year: 1994, Page(s):28 - 33
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (388 KB)

    This research concerns efficient multiprocessor threads-based implementation of reactive navigation for mobile robots. We present two important results: 1) Performance is improved significantly when CPU time allocated to individual navigational threads is adjusted dynamically according to a heuristic measure of their importance. 2) To implement this strategy, we present a multiprocessor scheduler ... 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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