Proceedings 20th IEEE Real-Time Systems Symposium (Cat. No.99CB37054)

1-3 Dec. 1999

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  • Proceedings 20th IEEE Real-Time Systems Symposium (Cat. No.99CB37054)

    Publication Year: 1999
    Request permission for reuse | PDF file iconPDF (341 KB)
    Freely Available from IEEE
  • Timing anomalies in dynamically scheduled microprocessors

    Publication Year: 1999, Page(s):12 - 21
    Cited by:  Papers (112)  |  Patents (2)
    Request permission for reuse | Click to expandAbstract | PDF file iconPDF (83 KB)

    Previous timing analysis methods have assumed that the worst-case instruction execution time necessarily corresponds to the worst-case behavior. We show that this assumption is wrong in dynamically scheduled processors. A cache miss, for example, can in some cases result in a shorter execution time than a cache hit. Many examples of such timing anomalies are provided. We first provide necessary co... View full abstract»

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  • Analysis of the impacts of overestimation sources on the accuracy of worst case timing analysis

    Publication Year: 1999, Page(s):22 - 31
    Cited by:  Papers (1)
    Request permission for reuse | Click to expandAbstract | PDF file iconPDF (138 KB)

    To predict the worst case execution time (WCET) of real-time tasks, we should consider various factors (e.g., caching, pipelining, and infeasible paths) that affect the accuracy of the prediction. However some of them are inherently difficult to analyze statically, and thus may give rise to significant overestimation in WCET prediction. Therefore, for more accurate WCET prediction, we need to iden... View full abstract»

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  • Deriving deadlines and periods for real-time update transactions

    Publication Year: 1999, Page(s):32 - 43
    Cited by:  Papers (15)
    Request permission for reuse | Click to expandAbstract | PDF file iconPDF (200 KB)

    Typically, temporal validity of real-time data is maintained by periodic update transactions. In this paper we examine the problem of period and deadline assignment for these update transactions such that (1) these transactions can be guaranteed to complete by their deadlines and (2) the imposed workload is minimized. To this end, we propose a novel approach, named More-Less principle. By applying... View full abstract»

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  • QoS provisioning with qContracts in web and multimedia servers

    Publication Year: 1999, Page(s):44 - 53
    Cited by:  Papers (20)
    Request permission for reuse | Click to expandAbstract | PDF file iconPDF (119 KB)

    The advent of performance-critical services such as online brokerage and e-commerce, as well as QoS-sensitive services such as streaming multimedia, makes existing FIFO servers incapable of meeting application QoS requirements. Re-designing server code to support QoS provisioning, on the other hand, is costly and time-consuming. To remedy this problem, we propose a new QoS-provisioning approach th... View full abstract»

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  • Design and evaluation of a feedback control EDF scheduling algorithm

    Publication Year: 1999, Page(s):56 - 67
    Cited by:  Papers (97)
    Request permission for reuse | Click to expandAbstract | PDF file iconPDF (182 KB)

    Despite the significant body of results in real-time scheduling, many real world problems are not easily supported. While algorithms such as Earliest Deadline First, Rate Monotonic, and the Spring scheduling algorithm can support sophisticated task set characteristics (such as deadlines, precedence constraints, shared resources, jitter etc.), they are all "open loop" scheduling algorithms. Open lo... View full abstract»

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  • New results on fixed priority aperiodic servers

    Publication Year: 1999, Page(s):68 - 78
    Cited by:  Papers (35)
    Request permission for reuse | Click to expandAbstract | PDF file iconPDF (167 KB)

    The issue of using the sporadic server (SS) for scheduling aperiodic tasks has received new attention under the POSIX standard as it has been proposed in P1003.1 d, the additional real-time extensions to POSIX. The SS has been traditionally considered a better approach to the deferrable server (DS) due to its supposed higher achievable utilisation. However, SS also has higher implementation comple... View full abstract»

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  • Optimal reward-based scheduling of periodic real-time tasks

    Publication Year: 1999, Page(s):79 - 89
    Cited by:  Papers (36)  |  Patents (2)
    Request permission for reuse | Click to expandAbstract | PDF file iconPDF (213 KB)

    Reward-based scheduling refers to the problem in which there is a reward associated with the execution of a task. In our framework, each real-time task comprises a mandatory and an optional part, with which a nondecreasing reward function is associated. Imprecise Computation and Increased-Reward-with-Increased-Service models fall within the scope of this framework. In this paper we address the rew... View full abstract»

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  • Cooperative scheduling of multiple resources

    Publication Year: 1999, Page(s):90 - 101
    Cited by:  Papers (13)  |  Patents (6)
    Request permission for reuse | Click to expandAbstract | PDF file iconPDF (180 KB)

    Obtaining simultaneous and timely access to multiple resources is known to be an NP-complete problem. Complete resource decoupling is, therefore, often used for managing end-to-end delays in distributed real-time system where each processor is scheduled independent of the others. This decoupling approach unfortunately fails when multiple resources must be managed within a single node. Resources su... View full abstract»

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  • Specification and analysis of soft real-time systems: quantity and quality

    Publication Year: 1999, Page(s):104 - 114
    Cited by:  Papers (6)
    Request permission for reuse | Click to expandAbstract | PDF file iconPDF (302 KB)

    This paper presents a process algebra for specifying soft real-time constraints in a compositional way. For these soft constraints we take a stochastic point of view and allow arbitrary probability distributions to express delays of activities. The semantics of this process algebra is given in terms of stochastic automata, a variant of timed automata where clocks are initialised randomly and run b... View full abstract»

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  • High-level modeling and analysis of TCAS

    Publication Year: 1999, Page(s):115 - 125
    Cited by:  Papers (14)
    Request permission for reuse | Click to expandAbstract | PDF file iconPDF (168 KB)

    In this paper we demonstrate a high-level approach to modeling and analyzing complex safety-critical systems through a case study in the area of air traffic management. In particular, we focus our attention on the Traffic Alert and Collision Avoidance System (TCAS); an on-board conflict detection and resolution system which alerts pilots to the presence of nearby aircraft that pose a mid-air colli... View full abstract»

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  • On the use of formal techniques for analyzing dependable real-time protocols

    Publication Year: 1999, Page(s):126 - 135
    Cited by:  Papers (2)
    Request permission for reuse | Click to expandAbstract | PDF file iconPDF (284 KB)

    The effective design of composite dependable and real time protocols entails demonstrating their proof of correctness and, in practice, the efficient delivery of services. We focus on these aspects of correctness and efficiency, specifically considering the real time aspects where the need is to ensure satisfaction of stringent timing and operational constraints. We establish the use of mathematic... View full abstract»

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  • SRDE-application of data similarity to process control

    Publication Year: 1999, Page(s):136 - 145
    Cited by:  Papers (5)  |  Patents (1)
    Request permission for reuse | Click to expandAbstract | PDF file iconPDF (88 KB)

    The concept of data similarity was introduced by T.-W. Kuo and A.K. Mok (1996) to capture the semantics of real time applications where the consistency requirement of a transaction can be relaxed modulo a binary relation on the data space. Even though the notion of data similarity is naturally suited to many applications in the process control industry, its adoption is hampered by the lack of an e... View full abstract»

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  • On the efficient scheduling of non-periodic tasks in hard real-time systems

    Publication Year: 1999, Page(s):148 - 151
    Cited by:  Papers (13)
    Request permission for reuse | Click to expandAbstract | PDF file iconPDF (76 KB)

    The paper presents linear time, online algorithms which guarantee and jointly schedule firm aperiodic, hard sporadic and periodic tasks in fixed priority real time systems. We develop and capitalize on a methodology which computes the spare capacity Z(a,b) exactly in time /spl Theta/(n), for arbitrary schedule intervals (a,b), which, to the best of our knowledge, is the first linear time algorithm... View full abstract»

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  • Enabling deadline scheduling for Java real-time computing

    Publication Year: 1999, Page(s):152 - 153
    Cited by:  Papers (3)
    Request permission for reuse | Click to expandAbstract | PDF file iconPDF (26 KB)

    We present a scheduling architecture that enables the implementation of deadline based scheduling policies. The architecture is used to give real time capabilities to a custom Java virtual machine. This framework retains a clear separation between generic kernel mechanisms and upper level scheduling classes. A pure earliest deadline first algorithm can be implemented, but enhanced policies such as... View full abstract»

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  • A framework for scheduler synthesis

    Publication Year: 1999, Page(s):154 - 163
    Cited by:  Papers (35)
    Request permission for reuse | Click to expandAbstract | PDF file iconPDF (301 KB)

    We present a framework integrating specification and scheduler generation for real time systems. In a first step, the system, which can include arbitrarily designed tasks (cyclic or sporadic, with or without precedence constraints, any number of resources and CPUs) is specified as a timed Petri net. In a second step, our tool generates the most general non preemptive online scheduler for the speci... View full abstract»

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  • On scheduling tasks in reliable real-time control systems

    Publication Year: 1999, Page(s):164 - 165
    Cited by:  Papers (1)
    Request permission for reuse | Click to expandAbstract | PDF file iconPDF (82 KB)

    Feedback control is one of the most common applications of real time systems. However, the design of controller frequencies, task scheduling and reliability engineering are often done separately, resulting in suboptimal results. The article provides an overview of an integrated approach to reliable real time controller design by optimizing the system control performance subject to schedulability a... View full abstract»

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  • A framework for provisioning of temporal QoS in core-based multicast routing

    Publication Year: 1999, Page(s):168 - 178
    Cited by:  Papers (1)
    Request permission for reuse | Click to expandAbstract | PDF file iconPDF (358 KB)

    We develop and evaluate a set of member join/leave and state update/refresh procedures for QoS provisioning in core-based multicast routing with explicit member join and soft state refresh procedures. Specifically, in our prior work (Hung-Ying Tyan et al., 1999), we devised eligibility tests to verify whether or not a new member can join a multicast tree at adequate QoS while not violating the exi... View full abstract»

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  • Transport of MPEG video with statistical loss and delay guarantees in ATM networks using a histogram-based source model

    Publication Year: 1999, Page(s):179 - 189
    Cited by:  Papers (3)
    Request permission for reuse | Click to expandAbstract | PDF file iconPDF (158 KB)

    Unlike deterministic real time communication in which excessive resources may be required for absolute performance guarantees, statistical real time communication seeks to achieve both probabilistic performance guarantees and efficient resource sharing. We propose a framework for statistical real time communication in ATM networks that provides delay guaranteed transport of MPEG coded video traffi... View full abstract»

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  • Efficient delay computation methods for an ATM network with real-time video traffic

    Publication Year: 1999, Page(s):190 - 199
    Cited by:  Papers (1)
    Request permission for reuse | Click to expandAbstract | PDF file iconPDF (147 KB)

    Consider a real time communication application running on top of an ATM network; we require the connection to provide a transmission guarantee for the real time service. Such transmission guarantee can only be possible if there exists an absolute and deterministic worst case delay bound on all the ATM cells within the real time connection. We present our approach in finding this worst case cell de... View full abstract»

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  • Parallel switching in connection-oriented networks

    Publication Year: 1999, Page(s):200 - 209
    Cited by:  Papers (2)
    Request permission for reuse | Click to expandAbstract | PDF file iconPDF (201 KB)

    Packet switching in connection-oriented networks that may have multiple parallel links between pairs of switches is considered. An efficient packet scheduling algorithm that guarantees a deterministic quality of service to connections with real time constraints is proposed; this algorithm is a generalization of some recent multiprocessor scheduling algorithms, and offers real time performance guar... View full abstract»

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  • Remote controlled mobile imaging in a high temperature tunnel environment

    Publication Year: 1999, Page(s):212 - 213
    Request permission for reuse | Click to expandAbstract | PDF file iconPDF (64 KB)

    A custom remote controlled vehicle was developed and tested for imaging data acquisition in high-temperature environments (up to 300/spl deg/C.) Through a wireless remote control system, an operator can position the cameras to visually inspect and measure temperature distributions on any surface area of a 50 meter long underground tunnel. Feedback to the operator is provided through three wireless... View full abstract»

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  • HoneyWEB: embedded web-based control applications

    Publication Year: 1999, Page(s):214 - 217
    Cited by:  Patents (2)
    Request permission for reuse | Click to expandAbstract | PDF file iconPDF (106 KB)

    High performance monitoring and control of real-time environments over the Internet is of importance to many users. The general public, as well as professionals, desires the ability to remotely acquire real-time information at their fingertips. This paper presents a smart network design for real-time data acquisition. A streamlined web server designed specifically for embedded applications produce... View full abstract»

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  • IP security impact on system performance in a distributed real-time environment

    Publication Year: 1999, Page(s):218 - 219
    Cited by:  Patents (1)
    Request permission for reuse | Click to expandAbstract | PDF file iconPDF (37 KB)

    Information security in Naval shipboard platforms is becoming increasingly important with the move towards distributed computing, increased automation, and Commercial Off The Shelf (COTS) systems. Additionally, there are hard real-time requirements that must be met in a combat system, which is a critical component of the total shipboard platform. Information security services and real-time service... View full abstract»

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  • Time based Linux for real-time NOWs and MPI/RT

    Publication Year: 1999, Page(s):220 - 221
    Cited by:  Papers (4)
    Request permission for reuse | Click to expandAbstract | PDF file iconPDF (44 KB)

    The Real-Time Message Passing Interface (MPI/RT) is a communication layer middleware standard that is aimed at providing guaranteed Quality of Service for data transfers on high performance networks. It poses "middleout" requirements both on applications and on the operating system. In this paper, we consider the "middledown" issues by modifying a POSIX compliant operating system in order to suppo... View full abstract»

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