Annual Symposium Reliability and Maintainability, 2004 - RAMS

26-29 Jan. 2004

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Displaying Results 1 - 25 of 125
  • A design tool for large scale fault-tolerant software systems

    Publication Year: 2004, Page(s):256 - 260
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (293 KB) | HTML iconHTML

    In order to assist software designers in the application of fault-tolerance techniques to large scale software systems, a computer-aided software design tool has been proposed and implemented that assess the criticality of the software modules contained in the system. This information assists designers in identifying weaknesses in large systems that can lead to system failures. Through analysis an... View full abstract»

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  • Reliability metrics and the REMM model

    Publication Year: 2004, Page(s):474 - 479
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (354 KB) | HTML iconHTML

    This paper discusses differences in the understanding and application of current reliability metrics across engineering disciplines within an aerospace environment. Differences in the interpretation of these metrics by designers, project managers and product support engineers within an organization may compromise the effectiveness of any technical or commercial decision-making that is based upon r... View full abstract»

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  • Accelerated stress testing to detect probabilistic software failures

    Publication Year: 2004, Page(s):249 - 255
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (328 KB) | HTML iconHTML

    This paper describes the advantages of accelerated stress testing and addresses the value of accelerated stressing to find probabilistic software failure modes. The value has been widely reported in discovery of traditional hardware-related failure modes, but has not been widely accepted as valuable in finding software errors. This paper provides a business case study in accelerated stressing to f... View full abstract»

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  • Determining evaluation criteria for a "seal of approval" process for probabilistic risk assessment analysis tools

    Publication Year: 2004, Page(s):466 - 473
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (431 KB) | HTML iconHTML

    This paper outlines initial work performed in the design of an approval process to meet the objective expectations, and initial work performed to define appropriate evidence to use in the process. The approval process in general to provide the framework for the discussion of the primary focus of the paper, the presentation of work performed to design and populate a proposed decision support tool, ... View full abstract»

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  • Computer aided software FMEA for unified modeling language based software

    Publication Year: 2004, Page(s):243 - 248
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (438 KB) | HTML iconHTML

    Model-based software development, particularly when it utilizes unified modeling language (UML) tools, provides artifacts that make programs more transparent. We use these capabilities to automate major steps in the generation of a software FMEA. Automation not only reduces the labor required but also makes the process repeatable and removes many subjective decisions that can impair the credibilit... View full abstract»

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  • Accelerated tests to determine the reliability of the cable-encapsulant interface

    Publication Year: 2004, Page(s):330 - 334
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (387 KB) | HTML iconHTML

    Encapsulants are mainly used with the cable in various outdoor products, to act as barriers against the operating environment. In some applications, the encapsulants can also be used to provide strain relief for the cable. The reliability of the cable-encapsulant interface is critical for product functionality as well as its long-term reliability. The reliability of this interface depends on the c... View full abstract»

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  • Requirements based system level risk modeling

    Publication Year: 2004, Page(s):500 - 506
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (364 KB) | HTML iconHTML

    Space exploration missions are often characterized by multiple phases and each phase in turn satisfies some objective or requirement. The success of the mission is measured by the degree to which these requirements are satisfied. Missions either aim to demonstrate a new technology, or to obtain new science data or a combination of both of these. During the mission design process, numerous trade st... View full abstract»

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  • Parametric fault trees with dynamic gates and repair boxes

    Publication Year: 2004, Page(s):459 - 465
    Cited by:  Papers (16)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (646 KB) | HTML iconHTML

    A new approach is proposed to include s-dependencies in fault tree (FT) models. With respect to previous techniques, the approach presented in this paper is based on two peculiar powerful features. First, adopting a parameterization technique, referred to as parametric FT (PFT), to fold equal subtrees (or basic events) in order to resort to a more compact FT representation. It is shown that parame... View full abstract»

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  • Nonparametric estimation of marginal failure distributions from dually censored automotive data

    Publication Year: 2004, Page(s):86 - 89
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (382 KB) | HTML iconHTML

    It is not uncommon that a component's reliability characteristics depend on two usage variables. As an example, for automotive components such variables are time in service and accumulated mileage. For certain airplane chassis components, these variables are accumulated flight hours and the number of landings. The problem of failure time distribution estimation from dually censored (at warranty li... View full abstract»

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  • Behavioural study of the general renewal process

    Publication Year: 2004, Page(s):237 - 242
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (430 KB) | HTML iconHTML

    This paper is intended to provide insights into the application of the GRP model. A repairable system model for the case of realistic maintenance, the so-called general renewal process (GRP), was introduced by allowing the goodness of repairs to be modelled from as-good-as-new (i.e. ORP) to same-as-old (i.e. NHPP). This is sometimes referred to as better-than-old-but-worse-than-new repair assumpti... View full abstract»

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  • A reliability block diagramming tool to describe networks

    Publication Year: 2004, Page(s):141 - 145
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (640 KB) | HTML iconHTML

    The proposed tool, using a novel "compression algorithm" is capable of reducing any complicated series-parallel system to a visible sequence of series and parallel blocks in a reliability block diagram (RBD) by first finding all existing paths, then algorithmically compressing all redundant component duplications and finally calculating an exact reliability and creating an encoding of the topology... View full abstract»

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  • Maintenance-oriented fault tree analysis of component importance

    Publication Year: 2004, Page(s):534 - 539
    Cited by:  Papers (4)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (344 KB) | HTML iconHTML

    In this paper we investigate and compare a set of existing component importance measures and select the most informative and appropriate one for guiding the maintenance of the system. Efficient methods to compute the selected measure are presented. An important concern in the traditional fault tree reliability analysis, common-cause failure, is also addressed in the component importance analysis u... View full abstract»

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  • Use of PSA tools and techniques in life cycle management of maintenance and operation of complex system

    Publication Year: 2004, Page(s):492 - 499
    Cited by:  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (914 KB) | HTML iconHTML

    This paper briefly discusses the uses of probabilistic safety analysis for life cycle optimization of maintenance and operation. The focus is on developing a time-dependent model for conditional failure intensity of component with incorporated effects of maintenance (major overhauls) that could be used in fault tree evaluations simulating various time points in the past or future. Likelihood funct... View full abstract»

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  • Accelerated stress testing for both hardware and software

    Publication Year: 2004, Page(s):346 - 351
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (294 KB) | HTML iconHTML

    Accelerated stress testing (AST) has been used in electronic, electromechanical, and mechanical systems to achieve robustness with high reliability primarily for hardware. For software products, the reliability program is often conducted separate from any hardware accelerated stress testing. Yet, many systems are consist of concurrent software and hardware issues. In addition, the stress testing p... View full abstract»

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  • Variation mode and effect analysis

    Publication Year: 2004, Page(s):364 - 369
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (469 KB) | HTML iconHTML

    In this paper, we introduce an engineering method, variation mode and effect analysis (VMEA) developed to systematically look for noise factors affecting key product characteristics (KPCs) early in product development. Conducted on a systematic basis, the goal of VMEA is to identify and prioritize noise factors that significantly contribute to the variability of KPCs and might yield unwanted conse... View full abstract»

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  • Criticality analysis of process systems

    Publication Year: 2004, Page(s):451 - 458
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (658 KB) | HTML iconHTML

    This paper presents a systematic methodology for formal criticality analysis of process systems, which properly accounts for process interactions, equipment failure, stochastic process variations and events related to process safety. Important extensions are also presented for the use of such criticality analysis tools for safety and maintenance considerations. In the first part a quantitative mea... View full abstract»

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  • Supporting maintenance decisions with expert and event data

    Publication Year: 2004, Page(s):593 - 599
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (361 KB) | HTML iconHTML

    A successful maintenance program incorporates planning and follow-up processes, including systematic feedback and data collection systems and routines. The aim of our study is to find methods for predicting the number of failures and the time to the next failure using expert data, which is updated with the collected event data. In this study, three methods for predicting the number of failures wer... View full abstract»

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  • Steady-state availability estimation using field failure data

    Publication Year: 2004, Page(s):81 - 85
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (368 KB) | HTML iconHTML

    This paper introduces a novel technique for computing confidence limits associated with steady-state availability estimation using field failure data. The proposed cumulative downtime distribution (CDD) method implements a simple, though powerful, availability inference procedure based on the statistical properties of the distribution of sample means of the cumulative system outage time. Another a... View full abstract»

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  • Modeling multiphased missions using stochastic Petri nets with aging tokens

    Publication Year: 2004, Page(s):232 - 236
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (531 KB) | HTML iconHTML

    Various aspects of reliability modeling for systems that undergo changes in configuration during their mission are investigated in the context of Petri nets. In general, the duration of each phase for such multiphase scenarios can be either instantaneous (e.g., failure to activate on demand), deterministic (e.g., takeoff, cruise, and landing phases of a given aircraft mission), or random (e.g., ti... View full abstract»

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  • Probabilistic structural analysis of ultra efficient engine technology ceramic matrix composite combustor liners

    Publication Year: 2004, Page(s):320 - 323
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (412 KB) | HTML iconHTML

    A probabilistic structural analysis of NASA's ultra efficient engine technology (UEET) ceramic matrix composite (CMC) combustor liners has been completed using the NESTEM Code. The purpose was to identify the maximum stress locations and perform a probabilistic structural analysis at these locations on the inner and outer liners for given thermal loadings to determine the probability of failure at... View full abstract»

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  • The challenge of space nuclear propulsion and power systems reliability

    Publication Year: 2004, Page(s):431 - 436
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (353 KB) | HTML iconHTML

    In October of 2002, The Power and Propulsion Office and The Risk Management Office of NASA Glenn Research Center in Cleveland, Ohio began developing the reliability, availability, and maintainability (RAM) engineering approach for the Space Nuclear Propulsion and Power Systems Project. The objective of the Space Nuclear Power and Propulsion Project is to provide safe and reliable propulsion and po... View full abstract»

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  • Effect of element initialization in synchronous networked control system to control quality

    Publication Year: 2004, Page(s):135 - 140
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (554 KB) | HTML iconHTML

    This paper presents some results on the modeling and analysis of networked control systems (NCS). The problem analyzed is the design of control systems whose elements are interconnected by a communication network. For modeling and simulations of NCS coloured Petri nets and design/CPN software tool were chosen. The simulation results of a simple tank system are presented, but within the research ac... View full abstract»

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  • Software complexity factor in software reliability assessment

    Publication Year: 2004, Page(s):190 - 194
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (508 KB) | HTML iconHTML

    A straightforward early-stage software reliability assessment method was proposed and applied to large-scale, software-intensive programs (M.L. Yin et al., 1998). In this method, software size (in KSLOC) was used as the primary complexity factor, due to the limitation of detailed information available during the early stage of a program. Now that failure data are available from those programs, our... View full abstract»

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  • Optimal design of a condition-based maintenance model

    Publication Year: 2004, Page(s):528 - 533
    Cited by:  Papers (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (257 KB) | HTML iconHTML

    System performance and associated gain can be improved by using efficient maintenance policies. The latest developments in maintenance models include condition-based maintenance strategies. This paper presents a condition-based maintenance model for a deteriorating system. Deterioration can be defined as a process where the important parameters of a system gradually worsen, and if left unattended,... View full abstract»

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  • Fleet performance under selective maintenance

    Publication Year: 2004, Page(s):571 - 576
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (339 KB) | HTML iconHTML

    Many organizations rely on the effective use of fleets of repairable equipment that must perform sets of sequential missions. Such fleets include production equipment used in manufacturing systems, material handling equipment used in warehousing, and transportation vehicles used in distribution. Unfortunately, most organizations do not possess sufficient maintenance resources to keep the fleet in ... View full abstract»

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