17th IEEE Real-Time Systems Symposium

4-6 Dec. 1996

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  • 17th IEEE Real-Time Systems Symposium

    Publication Year: 1996, Page(s):iii - vii
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    Freely Available from IEEE
  • Bounding completion times of jobs with arbitrary release times and variable execution times

    Publication Year: 1996, Page(s):2 - 12
    Cited by:  Papers (19)
    Request permission for reuse | Click to expandAbstract | PDF file iconPDF (1135 KB)

    In many real-time systems, the workload can be characterized as a set of jobs with linear precedence constraints among them. Jobs often have variable execution times and arbitrary release times. We describe three algorithms that can be used to compute upper bounds on completion times of such jobs scheduled on a priority-driven basis. The algorithms have different performance and complexity. Simula... View full abstract»

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  • On task schedulability in real-time control systems

    Publication Year: 1996, Page(s):13 - 21
    Cited by:  Papers (229)
    Request permission for reuse | Click to expandAbstract | PDF file iconPDF (826 KB)

    Most real-time computer-controlled systems are built in two separate steps, each in isolation: controller design and its digital implementation. Computational tasks that realize the control algorithms are usually scheduled by treating their execution times and periods as unchangeable parameters. Task scheduling therefore depends only on the limited computing resources available. On the other hand,... View full abstract»

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  • A multiframe model for real-time tasks

    Publication Year: 1996, Page(s):22 - 29
    Cited by:  Papers (58)
    Request permission for reuse | Click to expandAbstract | PDF file iconPDF (766 KB)

    The well-known periodic task model of Liu and Layland (1973) assumes a worst-case execution time bound for every task and may be too pessimistic if the worst-case execution time of a task is much longer than the average. We give a multiframe real-time task model which allows the execution time of a task to vary from one instance to another by specifying the execution time of a task in terms of a s... View full abstract»

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  • Middleware for distributed industrial real-time systems on ATM networks

    Publication Year: 1996, Page(s):32 - 38
    Cited by:  Papers (12)  |  Patents (3)
    Request permission for reuse | Click to expandAbstract | PDF file iconPDF (784 KB)

    We address the problem of middleware design for constructing ATM LAN based distributed industrial plant monitoring and control systems. In particular, we present a real-time client-server programming model based on a uniform ATM network. This model is being realized in our middleware called MidART. The middleware provides a set of industrial application specific but network transparent programming... View full abstract»

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  • Analysing APEX applications

    Publication Year: 1996, Page(s):39 - 44
    Cited by:  Papers (16)
    Request permission for reuse | Click to expandAbstract | PDF file iconPDF (571 KB)

    The next generation of civil aircraft may be produced using Integrated Modular Avionics (IMA). A component of IMA is APEX, a standard operating system interface. This supports a two-level scheduling scheme consisting of fixed priority scheduling within a statically generated cyclic schedule. This paper illustrates how APEX applications can be analysed for their response times and shows that there ... View full abstract»

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  • Operating system extensions for dynamic real-time applications

    Publication Year: 1996, Page(s):45 - 50
    Cited by:  Papers (11)  |  Patents (10)
    Request permission for reuse | Click to expandAbstract | PDF file iconPDF (691 KB)

    Current general purpose operating systems are unable to support a new class of applications that have the same requirements as conventional applications but with additional real-time constraints. We introduce a new real-time process abstraction to model such applications. We show how an operating system can support these processes by having an admission policy to ensure that all of the processes' ... View full abstract»

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  • Approximate reachability analysis of timed automata

    Publication Year: 1996, Page(s):52 - 61
    Cited by:  Papers (17)
    Request permission for reuse | Click to expandAbstract | PDF file iconPDF (906 KB)

    A promising approach to formal verification of real-time systems is to use timed automata to model systems, and then to check whether certain "unsafe" states are reachable. Although theoretically appealing, this approach has significant practical problems because it requires expensive computation of reachable states. Fortunately computing a superset of reachable states is sometimes much cheaper. R... View full abstract»

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  • Correctness of vehicle control systems-a case study

    Publication Year: 1996, Page(s):62 - 72
    Cited by:  Papers (4)
    Request permission for reuse | Click to expandAbstract | PDF file iconPDF (1063 KB)

    Several example vehicle deceleration manoeuvres arising in automated transportation systems are specified, and their correctness verified, using the hybrid I/O automaton model of (Lynch et al., 1995). All system components are formalized using hybrid I/O automata, and their combination described using automaton composition. The proofs use invariant assertions, simulation mappings, and differential... View full abstract»

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  • Reducing the number of clock variables of timed automata

    Publication Year: 1996, Page(s):73 - 81
    Cited by:  Papers (30)
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    Freely Available from IEEE
  • Predictability of real-time systems: a process-algebraic approach

    Publication Year: 1996, Page(s):82 - 91
    Cited by:  Papers (1)  |  Patents (1)
    Request permission for reuse | Click to expandAbstract | PDF file iconPDF (831 KB)

    This paper presents a testing-based semantic preorder that relates real-time systems given in the process description language TPL on the basis of the predictability of their timing behavior. This predictability is measured in terms of the amount of variability present in processes' "activity-completion times". The semantic preorder is shown to coincide with an already existing, well-investigated ... View full abstract»

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  • A framework for implementing objects and scheduling tasks in lock-free real-time systems

    Publication Year: 1996, Page(s):94 - 105
    Cited by:  Papers (14)  |  Patents (5)
    Request permission for reuse | Click to expandAbstract | PDF file iconPDF (1214 KB)

    We present an integrated framework for developing real time systems in which lock-free algorithms are employed to implement shared objects. There are two key objectives of our work. The first is to enable functionality for object sharing in lock-free real time systems that is comparable to that in lock based systems. Our main contribution toward this objective is an efficient approach for implemen... View full abstract»

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  • Optimizing a FIFO, scalable spin lock using consistent memory

    Publication Year: 1996, Page(s):106 - 114
    Cited by:  Papers (2)  |  Patents (1)
    Request permission for reuse | Click to expandAbstract | PDF file iconPDF (770 KB)

    The paper presents a FIFO queue based, scalable spin lock (FSSL) that: (1) uses only one atomic swap operation; (2) is scalable as it requires a constant amount of communication; (3) runs without a coherent cache support; and (4) provides a timing guarantee suitable for real time applications. The algorithm is optimal in the number of atomic operations required to solve the scalable mutual exclusi... View full abstract»

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  • The MSP.RTL real-time scheduler synthesis tool

    Publication Year: 1996, Page(s):118 - 128
    Cited by:  Papers (16)
    Request permission for reuse | Click to expandAbstract | PDF file iconPDF (1044 KB)

    MSP.RTL is a tool for producing real time schedulers for a wide variety of timing constraints. The input to MSP.RTL can be customized for different application domains, as long as their timing semantics can be expressed in RTL (real time logic). The scheduler synthesis algorithm treats the real time scheduling problem as a temporal constraint satisfaction problem with additional resource constrain... View full abstract»

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  • Tool support for the construction of statically analysable hard real-time Ada systems

    Publication Year: 1996, Page(s):129 - 135
    Cited by:  Papers (1)
    Request permission for reuse | Click to expandAbstract | PDF file iconPDF (737 KB)

    The paper maintains that fixed priority process based preemptive scheduling is, arguably, more convenient, flexible and responsive than conventional cyclic scheduling for the construction of new generation software intensive satellite control systems. Predictable usage of preemptive priority based scheduling, however, demands the support of mature static analysis techniques. Worst case response ti... View full abstract»

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  • High availability in the real-time publisher/subscriber inter-process communication model

    Publication Year: 1996, Page(s):136 - 141
    Cited by:  Papers (4)  |  Patents (4)
    Request permission for reuse | Click to expandAbstract | PDF file iconPDF (705 KB)

    The real time publisher/subscriber (RT P/S) communications model has been proposed as a flexible and powerful interprocess communication model for distributed real time systems (R. Rajkumar et al., 1995). It can also be used as the underlying framework for supporting building blocks such as extensible cells and replaceable software units far building evolvable distributed real time systems. Howeve... View full abstract»

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  • Structuring communication software for quality-of-service guarantees

    Publication Year: 1996, Page(s):144 - 154
    Cited by:  Papers (15)  |  Patents (3)
    Request permission for reuse | Click to expandAbstract | PDF file iconPDF (1369 KB)

    We propose architectural mechanisms for structuring host communication software to provide QoS guarantees. In particular, we present and evaluate a QoS sensitive communication subsystems architecture for end hosts that provides real time communication support for generic network hardware. This architecture provides services for managing communication resources for guaranteed QoS (real time) connec... View full abstract»

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  • Multirate scheduling for guaranteed and predictive services in ATM networks

    Publication Year: 1996, Page(s):155 - 164
    Cited by:  Papers (6)
    Request permission for reuse | Click to expandAbstract | PDF file iconPDF (907 KB)

    We propose a multirate service mechanism that allows a network session to be served at different rates at different times. Applications generating bursty data, such as VBR video, can take advantage of multirate service by requesting a high rate of service for brief periods of bursty arrivals and a lower rate of service at other times. Consequently, an application can improve its delay performance ... View full abstract»

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  • Message transmission with timing constraints in ring networks

    Publication Year: 1996, Page(s):165 - 174
    Cited by:  Papers (1)
    Request permission for reuse | Click to expandAbstract | PDF file iconPDF (1021 KB)

    We consider the message transmission problem in unidirectional slotted ring networks. We consider two operation modes: 1) the evacuation mode, in which all messages arrive before system initialization and no new message arrives during system operation; and 2) the continuation mode, in which new messages may arrive after system initialization. We study the performance of several message scheduling ... View full abstract»

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  • On supporting time-constrained communications in WDMA-based star-coupled optical networks

    Publication Year: 1996, Page(s):175 - 184
    Cited by:  Papers (6)
    Request permission for reuse | Click to expandAbstract | PDF file iconPDF (1186 KB)

    We devise a preallocation based single hop wavelength division multiple access (WDMA) scheme to support time constrained communication in star coupled optical networks. We consider a star coupled broadcast and select network architecture in which N stations are connected to a star coupler with W different wavelength channels. Each of the W wavelength channels is slotted and shared by the N station... View full abstract»

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  • Real-time queueing theory

    Publication Year: 1996, Page(s):186 - 195
    Cited by:  Papers (69)
    Request permission for reuse | Click to expandAbstract | PDF file iconPDF (1025 KB)

    The paper presents an approach to real time system scheduling. The approach, called real time queueing theory, includes customer timing requirements into queueing models. With real time queueing models, one is able to explicitly characterize the dynamic behavior of the customer lead time profile process where lead time=deadline minus current time. In spite of the infinite dimensionality of these p... View full abstract»

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  • An optimal pinwheel scheduler using the single-number reduction technique

    Publication Year: 1996, Page(s):196 - 205
    Cited by:  Papers (16)  |  Patents (11)
    Request permission for reuse | Click to expandAbstract | PDF file iconPDF (833 KB)

    Several pinwheel schedulers have been reported previously for scheduling real-time systems in which the temporal distances between consecutive executions of tasks must be less than their respective distance constraints. The scheduler Sr has been used for task sets with real number distance constraints and execution times. Sr transforms the distance constraints in a system into harmonic values with... View full abstract»

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  • Integrated scheduling of multimedia and hard real-time tasks

    Publication Year: 1996, Page(s):206 - 217
    Cited by:  Papers (26)  |  Patents (8)
    Request permission for reuse | Click to expandAbstract | PDF file iconPDF (1247 KB)

    An integrated platform which is capable of meeting the requirements of both traditional real-time control processing and multimedia processing has enormous potential for accommodating various kinds of new applications. However, except for the simplest of situations, few, if any, research or commercial systems successfully provide architectural and OS mechanisms which can efficiently support both h... View full abstract»

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  • Commit processing in distributed real-time database systems

    Publication Year: 1996, Page(s):220 - 229
    Cited by:  Papers (24)
    Request permission for reuse | Click to expandAbstract | PDF file iconPDF (970 KB)

    We investigate the performance implications of supporting transaction atomicity in a distributed real-time database system. Using a detailed simulation model of a firm-deadline distributed real-time database system, we profile the real-time performance of a representative set of commit protocols. A new commit protocol that is designed for the real-time domain and allows transactions to "optimistic... View full abstract»

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  • Value-cognizant admission control for RTDB systems

    Publication Year: 1996, Page(s):230 - 239
    Cited by:  Papers (16)
    Request permission for reuse | Click to expandAbstract | PDF file iconPDF (1152 KB)

    Admission control and overload management techniques are central to the design and implementation of real-time database systems. We motivate the need for these mechanisms and present protocols for adding such capabilities to real-time databases. In particular, we present a novel admission control paradigm, we describe a number of admission control strategies and contrast (through simulations) thei... View full abstract»

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