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Proceedings of Third Workshop on Parallel and Distributed Real-Time Systems

25-25 April 1995

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  • Proceedings of Third Workshop on Parallel and Distributed Real-Time Systems

    Publication Year: 1995
    Request permission for commercial reuse | PDF file iconPDF (126 KB)
    Freely Available from IEEE
  • Atomic broadcast: a case study in locative temporal logic

    Publication Year: 1995, Page(s):175 - 183
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (576 KB)

    Locative temporal logic (LTL) has been developed for the specification and verification of distributed real time systems. It is a two-sorted modal logic in the sense that linear time temporal logic has been extended by a locative sort modelling communication networks. In its intended application area, LTL is more intuitive and adequate than other observer-based approaches because it is moulded aft... View full abstract»

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  • Verification of schedulability of real-time systems with extended time Petri nets

    Publication Year: 1995, Page(s):185 - 192
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (528 KB)

    Most verification algorithms for schedulability of real-time systems are based on an approximate computation which only considers worst cases. Although they always find correct schedulings, in which any task never violates its deadline, those schedulings are sometimes too strict. In this paper, in order to verify schedulability more precisely we propose a verification method based on the state spa... View full abstract»

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  • Timing insensitive binary-to-binary migration across multiprocessor architectures

    Publication Year: 1995, Page(s):193 - 194
    Cited by:  Papers (2)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (188 KB)

    TIBBIT is a method of performing a binary to binary translation of an application from one architecture (source) to another (target) while maintaining the timing behavior of the code, even when it depends upon the speed (e.g. clock rate) of the host processor. Translated applications are scheduled under a real-time operating system on the target system such that processor-speed dependent behavior ... View full abstract»

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  • The peer tasking design method

    Publication Year: 1995, Page(s):20 - 29
    Cited by:  Papers (2)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (972 KB)

    This paper is a preliminary report of an ARPA sponsored study. It focuses on designing real-time command and control or battle management systems for parallel and distributed architectures. Due to delays in other ARPA programs, the targeted architectures were not available during the time frame of the study. The results of the study were, however, tested on more conventional sequential and paralle... View full abstract»

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  • Scheduling tasks in real-time systems using evolutionary strategies

    Publication Year: 1995, Page(s):195 - 196
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (160 KB)

    Finding feasible schedules for tasks running in hard, real-time distributed computing systems is generally NP-hard. This paper describes a heuristic algorithm using evolutionary strategies. Our results indicate that the evolutionary strategies can find feasible schedules (assuming they exist) in very short periods of time View full abstract»

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  • Runtime reallocation of divisible load under processor execution deadlines

    Publication Year: 1995, Page(s):30 - 31
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (168 KB)

    We examine the problem of optimizing the reallocation and execution of divisible load originating in different amounts at the sites of an interconnected set of heterogeneous processors characterized by their load computing speeds and I/O speeds. Each processor imposes, a priori, a hard deadline on its allocated task completion. The objective of load retasking and redistribution, which is implement... View full abstract»

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  • Optimized priority assignment for tasks and messages in distributed hard real-time systems

    Publication Year: 1995, Page(s):124 - 132
    Cited by:  Papers (41)  |  Patents (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (548 KB)

    Recent advances in the analysis of distributed realtime systems have made it possible to predict if hard realtime requirements will be met. However, it is still difficult to find a feasible priority assignment when the utilization levels of the CPUs and communication networks are pushed near to their limits. This paper presents a new heuristic algorithm for optimizing the assignment of priorities ... View full abstract»

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  • Distributed and parallel execution in Ada 83

    Publication Year: 1995, Page(s):52 - 61
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (856 KB)

    Since the standardization of the Ada programming language in 1989, much research has gone into the distribution of Ada programs across a number of separate processors. However, no standard for distribution of Ada 89 programs has emerged. A new language standard, known as Ada 95, includes explicit support for the distribution of Ada programs. This paper describes the techniques and a graphical tool... View full abstract»

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  • Model-based system development

    Publication Year: 1995, Page(s):2 - 3
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (168 KB)

    Reactive systems, i.e. systems reacting to events in their environment, base their operation on models of the objects of interest in the environment. In the current practice these models are implemented as algorithms ultimately relating observations to actions. This approach results in systems that are rather inflexible and sometimes difficult to maintain. In addition, the different uses made of t... View full abstract»

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  • Avoiding deadline decay under transient overloads

    Publication Year: 1995, Page(s):198 - 200
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (252 KB)

    Deadline scheduling policies based on stochastic computation times perform well in average but fail in presence of transient overloads, causing already scheduled tasks to miss their deadline. This paper presents an approach using medium-term scheduling policies to cope with the problem of transient overload in dynamic real-time systems. The proposed approach has been implemented in a Real-Time Dis... View full abstract»

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  • Design of a communication scheme for a distributed controller architecture using stochastic Petri nets

    Publication Year: 1995, Page(s):147 - 154
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (536 KB)

    This paper describes a modeling project which was established to support the design of a distributed controller system. An anthropomorphic robot hand is the target system. Stochastic Petri net models for different communication schemes were developed in order to predict the performance of the considered systems. For a given workload a bus communication can not be used, but two alternative ring str... View full abstract»

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  • Real-time networking over HIPPI

    Publication Year: 1995, Page(s):76 - 83
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (540 KB)

    HIPPI provides a very-high-speed communication medium, which is very well suited for a large number of bandwidth-demanding distributed applications. Unfortunately, its circuit-switched nature makes it very difficult to provide real-time guarantees when connections contend for network resources. We present a time-division-multiplex access scheme designed to give timing guarantees to high-speed conn... View full abstract»

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  • Partitioning Ada programs for distributed platforms

    Publication Year: 1995, Page(s):33 - 34
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (140 KB)

    Few work has been done in the past which has dealt with programming for loosely coupled distributed systems. However, distributed execution is becoming increasingly important for real time systems, since most of them are implemented with distributed processors. Programming multiprocessors through a single program approach offers many advantages from a software engineering point of view like, abstr... View full abstract»

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  • SATURNE: a reactive-anytime programming model for intelligent embedded real-time systems

    Publication Year: 1995, Page(s):134 - 135
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (196 KB)

    One of the major challenge of next embedded systems is to involve intelligence while preserving the classical real-time properties: (a) reactivity, i.e. the capability to react continuously towards asynchronous inputs, and (b) predictability. Furthermore, one of the main property which is requested in this kind of systems operating in a highly non-deterministic outside environment, is adaptability... View full abstract»

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  • Object-oriented programming with protected types in Ada 95

    Publication Year: 1995, Page(s):62 - 68
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (340 KB)

    Integrating concurrent and object-oriented language facilities is currently an active research area. There are a few experimental languages which attempt to combine various models of concurrency within an OOP framework. Most of these suffer from the so called inheritance anomaly where a concurrent object's synchronisation code needs to be modified if the object is extended. Ada 95 has avoided some... View full abstract»

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  • On the modeling of distributed real-time systems

    Publication Year: 1995, Page(s):4 - 5
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (188 KB)

    This paper discusses the requirements for the modeling of distributed real-time systems, both from an engineering and a reengineering point of view. A suitable extension of the object-oriented paradigm with execution graphs, modeled as partial orders, is briefly described. The objects and execution graphs are attended with annotations suitable for the description of non-fictional system properties... View full abstract»

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  • Real-time computing cornerstones: a system engineer's view

    Publication Year: 1995, Page(s):8 - 9
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (184 KB)

    Common attributes are found in both military and commercial real-time systems. The existence of these common threads suggests that there may be key quantitative system design considerations that undergird large scale, real-time system design. Identifying and quantifying these key aspects early in a program is important in insuring the success of a design. This paper suggests a candidate list of su... View full abstract»

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  • A study of network routers for real-time parallel computers

    Publication Year: 1995, Page(s):202 - 203
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (156 KB)

    A candidate network function is accurately defined for real-time parallel computers. A concise, time-driven, flit-based, priority-driven, wormhole-routed, network simulator has been designed. Experimentation is performed by monitoring the latency and the throughput with variations in different network parameters. Initially the destination address, message length and message priority are generated ... View full abstract»

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  • The challenge of the increased use of COTS: a developer's perspective

    Publication Year: 1995, Page(s):155 - 159
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (420 KB)

    Standard hardware performance and cost concerns are increasingly driving designers of real-time systems toward the use of Commercial Off-The-Shelf (COTS) components. There are many difficulties with this transition yet there is a perceived lack of interest in the subject. It is speculated that the community is not fully aware of the problems being encountered in utilizing COTS components. This pap... View full abstract»

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  • Real-time multimedia network system using VLIW hardware stack processor

    Publication Year: 1995, Page(s):84 - 89
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (336 KB)

    We propose a multimedia network system using VLIW hardware stack processors, which supports mainly the presentation layer of OSI protocol and fits various real-time applications including intelligent processing View full abstract»

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  • A specification language for parallel real-time systems

    Publication Year: 1995, Page(s):165 - 174
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (692 KB)

    Parallel high-performance computing is gaining momentum as a computing platform for many applications. In recent years, the research in software support for parallel computers has mainly addressed scientific and information processing applications. Very little attention has been paid to real-time embedded system requirements on parallel machines. This research investigates some important issues re... View full abstract»

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  • On building distributed soft real-time systems

    Publication Year: 1995, Page(s):13 - 19
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (488 KB)

    When building a distributed real-time system, one can either build the whole system from scratch, or from pre-existing standard components. Although the former allows better scheduling design, it may not be economical in terms of the cost and time of development. This paper studies the performance of distributed soft real-time systems that use standard components with various scheduling algorithms... View full abstract»

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  • Drawing execution graphs by parsing

    Publication Year: 1995, Page(s):113 - 122
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (668 KB)

    We present an algorithm for drawing execution graphs. Such graphs represent the control flow in a program. The fact that a program is constructed according to a grammar is reflected in the corresponding execution graph. Therefore, we introduce graph production rules that are based on generally used programming language constructs. Each rule is applied to a certain class of topologies of the graph.... View full abstract»

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  • On the use of Ada tasking in the building of satellite control software

    Publication Year: 1995, Page(s):44 - 51
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (544 KB)

    An increasing proportion of the critical control activities performed on board of modern satellite systems is nowadays being implemented in software. The resulting software systems have thus to accommodate a large spectrum of processing requirements, which shows an increasing demand for event-driven activities. Hence, process-oriented preemptive priority-based scheduling is most suited for use in ... View full abstract»

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