91,671 research outputs found

    FIESTA: An operational decision aid for space network fault isolation

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    The Fault Tolerance Expert System for Tracking and Data Relay Satellite System (TDRSS) Applications (FIESTA) is a fault detection and fault diagnosis expert system being developed as a decision aid to support operations in the Network Control Center (NCC) for NASA's Space Network. The operational objectives which influenced FIESTA development are presented and an overview of the architecture used to achieve these goals are provided. The approach to the knowledge engineering effort and the methodology employed are also presented and illustrated with examples drawn from the FIESTA domain

    The model and method of SCADA diagnostics as an object with partially defined parameters

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    Modern SCADA are widely spread all over the world to control technological processes in different industries such as power engineering, military, transport, etc. These systems have strict requirements to ensure their fault tolerance and reliability. Therefore, a very important problem is to perform real time self-diagnostics for mission critical SCADA. We propose a diagnostic model based on expert system methodology to solve this issue

    THE MODEL AND METHOD OF SCADA DIAGNOSTICS AS AN OBJECT WITH PARTIALLY DEFINED PARAMETERS

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    Modern SCADA are widely spread all over the world to control technological processes in different industries such as power engineering, military, transport, etc. These systems have strict requirements to ensure their fault tolerance and reliability. Therefore, a very important problem is to perform real time self-diagnostics for mission critical SCADA. We propose a diagnostic model based on expert system methodology to solve this issue

    Preliminary design of the redundant software experiment

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    The goal of the present experiment is to characterize the fault distributions of highly reliable software replicates, constructed using techniques and environments which are similar to those used in comtemporary industrial software facilities. The fault distributions and their effect on the reliability of fault tolerant configurations of the software will be determined through extensive life testing of the replicates against carefully constructed randomly generated test data. Each detected error will be carefully analyzed to provide insight in to their nature and cause. A direct objective is to develop techniques for reducing the intensity of coincident errors, thus increasing the reliability gain which can be achieved with fault tolerance. Data on the reliability gains realized, and the cost of the fault tolerant configurations can be used to design a companion experiment to determine the cost effectiveness of the fault tolerant strategy. Finally, the data and analysis produced by this experiment will be valuable to the software engineering community as a whole because it will provide a useful insight into the nature and cause of hard to find, subtle faults which escape standard software engineering validation techniques and thus persist far into the software life cycle

    Decoupling Simulated Annealing From Massive Multiplayer Online Role-Playing Games in RAID

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    End-users agree that compact technology are an interesting new topic in the field of electri- cal engineering, and physicists concur. In fact, few futurists would disagree with the deploy- ment of Byzantine fault tolerance, demonstrates the structured importance of cryptography. We construct a novel algorithm for the simulation of write-ahead logging (JDL), validating that Byzantine fault tolerance can be made peer-to- peer, classical, and stable. It is often an important mission but is supported by previous work in the field

    Formal specification of requirements for analytical redundancy-based fault -tolerant flight control systems

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    Flight control systems are undergoing a rapid process of automation. The use of Fly-By-Wire digital flight control systems in commercial aviation (Airbus 320 and Boeing FBW-B777) is a clear sign of this trend. The increased automation goes in parallel with an increased complexity of flight control systems with obvious consequences on reliability and safety. Flight control systems must meet strict fault-tolerance requirements. The standard solution to achieving fault tolerance capability relies on multi-string architectures. On the other hand, multi-string architectures further increase the complexity of the system inducing a reduction of overall reliability.;In the past two decades a variety of techniques based on analytical redundancy have been suggested for fault diagnosis purposes. While research on analytical redundancy has obtained desirable results, a design methodology involving requirements specification and feasibility analysis of analytical redundancy based fault tolerant flight control systems is missing.;The main objective of this research work is to describe within a formal framework the implications of adopting analytical redundancy as a basis to achieve fault tolerance. The research activity involves analysis of the analytical redundancy approach, analysis of flight control system informal requirements, and re-engineering (modeling and specification) of the fault tolerance requirements. The USAF military specification MIL-F-9490D and supporting documents are adopted as source for the flight control informal requirements. The De Havilland DHC-2 general aviation aircraft equipped with standard autopilot control functions is adopted as pilot application. Relational algebra is adopted as formal framework for the specification of the requirements.;The detailed analysis and formalization of the requirements resulted in a better definition of the fault tolerance problem in the framework of analytical redundancy. Fault tolerance requirements and related certification procedures turned out to be considerably more demanding than those typically adopted in the literature. Furthermore, the research work brought up to light important issues in all fields involved in the specification process, namely flight control system requirements, analytical redundancy, and requirements engineering
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