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Real-Time Systems Symposium, 1991. Proceedings., Twelfth

Date 4-6 Dec. 1991

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  • Proceedings. Twelfth Real-Time Systems Symposium (Cat. No.91CH3090-8)

    Publication Year: 1991
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    Freely Available from IEEE
  • Clairvoyance, capricious timing faults, causality, and real-time specifications

    Publication Year: 1991, Page(s):254 - 263
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (816 KB)

    The authors examine the issues of satisfiability, clairvoyance, the demonstrable existence of timing faults, and event causality, all in the context of formal methods for real-time systems. Representative languages and logics are introduced to illustrate the points. The authors introduce SRSL, a simplified specification language used to illustrate the issues involved. They examine these issues in ... View full abstract»

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  • Specification and verification of real-time embedded systems using time-constrained reactive automata

    Publication Year: 1991, Page(s):244 - 253
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (848 KB)

    The authors briefly review the time-constrained reactive automata (TRA) model and its use in the specification and verification of real-time embedded systems. Among its salient features is a fundamental notion of space and time that restricts the expensiveness of the model in a way that allows the specification of only reactive, spontaneous, and causal computation. Using the TRA formalism, there i... View full abstract»

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  • Earliest deadline scheduling for real-time database systems

    Publication Year: 1991, Page(s):232 - 242
    Cited by:  Papers (71)  |  Patents (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (872 KB)

    A new priority assignment algorithm called adaptive earliest deadline (AED) is given that stabilizes the overload performance of the earliest deadline policy in a real-time database system (RTDBS) environment. The AED algorithm uses a feedback control mechanism to achieve this objective and does not require knowledge of transaction characteristics. Using a detailed simulation model, the authors co... View full abstract»

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  • MACS: a predictable architecture for real time systems

    Publication Year: 1991, Page(s):296 - 305
    Cited by:  Papers (6)  |  Patents (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (752 KB)

    The MACS (multiple active context system) architecture is a high-performance, multiple context, cacheless processor designed around the goal of predictability. Multiple contexts provide highly predictable memory and pipeline performance, while at the same time allowing multiple threads to execute with independent timing characteristics. The design emphasis is on provable execution speed and indepe... View full abstract»

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  • RTC: language support for real-time concurrency

    Publication Year: 1991, Page(s):43 - 52
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (816 KB)

    Language constructs for the expression of timing and concurrency requirements in distributed real-time programs are presented. The approach to concurrent real-time programming is to explicitly express real-time concurrency constraints in a program and allow the run-time system to enforce them. To define these constraints precisely, the authors develop a real-time concurrency model that combines an... View full abstract»

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  • Enhancing real-time DBMS performance with multiversion data and priority based disk scheduling

    Publication Year: 1991, Page(s):222 - 231
    Cited by:  Papers (13)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (788 KB)

    Real-time multiversion concurrency control algorithms are proposed, to: increase concurrency, adjust the serialization order dynamically and work without an estimate of a transaction's runtime. The authors also propose disk scheduling algorithms which consider not only the transactions which request input/output (I/O) but also those affected by I/O. They consider transactions which are directly af... View full abstract»

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  • The transient server approach to scheduling time-critical recovery operations

    Publication Year: 1991, Page(s):286 - 295
    Cited by:  Papers (11)  |  Patents (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (808 KB)

    A scheduling approach is given for servicing the nondeterministic workload demands of time-critical recovery operations triggered by the detection of errors in periodic real-time workloads. This approach, referred to as the transient server, has been developed within the context of fixed-priority preemptive systems. For these systems, it is proved that deadline monotonic scheduling is optimal in m... View full abstract»

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  • Run-time monitoring of real-time systems

    Publication Year: 1991, Page(s):74 - 83
    Cited by:  Papers (41)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (748 KB)

    A model and an implementation of a run-time environment for specifying and monitoring properties of real-time systems are presented. The proposed approach supports annotating real-time programs with events that are recorded and examined at run-time. The authors provide two general methods for synchronous or asynchronous monitoring of real-time constraints. In the synchronous case, a system constra... View full abstract»

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  • Towards an automatic synthesis system for real-time software

    Publication Year: 1991, Page(s):34 - 42
    Cited by:  Papers (10)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (768 KB)

    An automatic synthesis system for real-time software is described. It is argued that the presence of strict operation requirements, such as task-level timing constraints and compiler and target platform constraints, guides synthesis. An automatic software synthesis system, RT-SYN, integrates platform characteristics to synthesize real-time software which meets hard deadline design requirements. Th... View full abstract»

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  • On using priority inheritance in real-time databases

    Publication Year: 1991, Page(s):210 - 221
    Cited by:  Papers (22)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (944 KB)

    The authors investigate solutions to the priority inversion problem in a real-time database where two-phase locking is employed for concurrency control. They examine two basic schemes for addressing the priority inversion problem, one based on priority inheritance and the other based on priority abort. The authors also study a new scheme, called conditional priority inheritance, which attempts to ... View full abstract»

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  • A priority ceiling protocol for multiple-instance resources

    Publication Year: 1991, Page(s):140 - 149
    Cited by:  Papers (6)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (680 KB)

    A systematic optimization process for multiple-instance resource sharing in real-time systems is presented. The authors derive the schedulability condition for systems with such resources and present an algorithm which can be used to divide a resource pool into smaller groups in order to improve the worst-case blocking behavior. They present the system model used and review some related work. The ... View full abstract»

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  • Using objects and actions to provide fault tolerance in distributed, real-time applications

    Publication Year: 1991, Page(s):276 - 285
    Cited by:  Papers (7)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (668 KB)

    An object-oriented model is developed for structuring distributed real-time applications. Atomic atoms (atomic transactions) and exception handling techniques are used to introduce fault tolerance. Additional techniques are then developed to permit application and device specific commit and abort processing. Objects can be replicated to increase their availability. The authors examine the reasons ... View full abstract»

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  • A partial evaluator for the Maruti hard real-time system

    Publication Year: 1991, Page(s):64 - 73
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (708 KB)

    The use of high-level programming constructs makes it difficult to estimate at compile-time the execution time and resource requirements of a program. The authors contend that partial evaluation provides a solution to this problem. They describe the application of partial evaluation to programming languages for hard-real-time systems and give examples of programs handled by the techniques. They di... View full abstract»

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  • Efficient synchronization of clocks in a distributed system

    Publication Year: 1991, Page(s):22 - 31
    Cited by:  Papers (5)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (820 KB)

    A probabilistic clock synchronization algorithm is proposed where processors in the system exchange time stamps and synchronize to a common clock value. Most of the previous algorithms for this problem have been based on a master-slave approach where all the slave processors synchronize to the clock value of a master. These algorithms are not distributed in nature and some of the assumptions made ... View full abstract»

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  • Real-time features for Ada 9X

    Publication Year: 1991, Page(s):172 - 180
    Cited by:  Papers (5)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (856 KB)

    Ada 9X is a revision of the Ada programming language standard. This revision includes some changes that are intended to improve Ada's usefulness for real-time applications. The changes under consideration include multiple clocks, new forms of delay statements, a new low-level data synchronization scheme based on a limited form of priority inheritance, and a mechanism for asynchronously controlling... View full abstract»

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  • Hartstone distributed benchmark: requirements and definitions

    Publication Year: 1991, Page(s):199 - 208
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (724 KB)

    A series of benchmark requirements, the Hartstone distributed benchmark (HDB), to be used in testing the ability of real-time distributed systems (RTDSs), to handle real-time applications, is defined. The HDB experiments deliver figures of merit for the end-to-end scheduling of messages, which integrates the processor scheduling domain and the communication scheduling domain. In the HDB experiment... View full abstract»

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  • On non-preemptive scheduling of period and sporadic tasks

    Publication Year: 1991, Page(s):129 - 139
    Cited by:  Papers (156)  |  Patents (14)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (824 KB)

    A fundamental problem in the theory of real-time scheduling is examined: scheduling a set of periodic or sporadic tasks on a uniprocessor without preemption and without inserted idle time. The authors give a necessary and sufficient set of conditions C for a set of periodic or sporadic tasks to be schedulable for arbitrary release times of the tasks. They show that any set of periodic or ... View full abstract»

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  • A requirements specification method for adaptive real-time systems

    Publication Year: 1991, Page(s):264 - 273
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (688 KB)

    A method for facilitating the specification and analysis of semihard real-time systems is described. The authors introduce the notion of an activity, the fundamental unit of computation upon which the methodology is based. They present a notation for creating an integrated requirements model which addresses the functional, behavioral, temporal, and information aspects of a semihard real-time syste... View full abstract»

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  • The diffusion model based task remapping for distributed real-time systems

    Publication Year: 1991, Page(s):2 - 11
    Cited by:  Papers (2)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (700 KB)

    A fault-tolerant architecture for loosely coupled distributed real-time systems is considered and a distributed task management method that aims at network-wide fault tolerance, compatible with flexible resource utilization is proposed. The task management method includes a checkpoint data transfer mechanism and an adaptive task remapping mechanism. A policy of task remapping is based on the therm... View full abstract»

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  • Program representation and translation for predictable real-time systems

    Publication Year: 1991, Page(s):53 - 63
    Cited by:  Papers (29)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (960 KB)

    A basic approach to the problem of program translation for systems using explicit plan scheduling is described. One of the goals is to establish a source language, Spring-C, that can serve as a target for many languages. The author discusses a method for deriving behavioral predictions while translating between the programming and run-time representations used by the Spring system. A graph represe... View full abstract»

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  • An object oriented model for parallel and reactive systems

    Publication Year: 1991, Page(s):84 - 93
    Cited by:  Papers (30)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (692 KB)

    MO2 is an object-oriented model which integrates features of database management systems (DBMSs) and features of real-time systems. It allows for the definition of different kinds of relationships between objects: generalization/specialization, aggregation, and association. Its principal feature is the ability to distinguish passive objects and active objects. The passive objects react only throug... View full abstract»

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  • Optimization in real time

    Publication Year: 1991, Page(s):150 - 159
    Cited by:  Papers (1)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (732 KB)

    A search algorithm called real-time search (RTS) for solving combinatorial optimization problems under real-time constraints is presented. The algorithm aims at finding the best possible solution within a given deadline. Since this objective is generally not achievable without first solving the problem, the authors use an alternative heuristic objective that looks for the solution with the best as... View full abstract»

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  • Building a predictable avionics platform in Ada: a case study

    Publication Year: 1991, Page(s):181 - 189
    Cited by:  Papers (60)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (776 KB)

    In an effort to promote the use of Ada in embedded system development, a realistic avionics application model whose hard real-time properties are fully predictable has been generated. This was done starting with a rate monotonic analysis of a set of typical fully synchronized periodic and aperiodic avionics tasks drawn from an idealized attack aircraft mission computer. The authors describe this a... View full abstract»

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  • Version selection schemes for hard real-time communications

    Publication Year: 1991, Page(s):12 - 21
    Cited by:  Papers (4)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (760 KB)

    Version selection schemes for hard real-time communications in multiaccess networks are studied. Two classes of version selection schemes are proposed: those that are based on message time constraints and those that are based on the network traffic. The authors discuss the design and implementation of both classes of version selection schemes used in conjunction with a window-based media access pr... View full abstract»

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