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Reliability and Maintainability Symposium, 2008. RAMS 2008. Annual

Date 28-31 Jan. 2008

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Displaying Results 1 - 25 of 109
  • [Front cover]

    Publication Year: 2008 , Page(s): c1
    Save to Project icon | Request Permissions | PDF file iconPDF (77 KB)  
    Freely Available from IEEE
  • Dawn to dusk - life cycle prescriptions

    Publication Year: 2008 , Page(s): c2
    Save to Project icon | Request Permissions | PDF file iconPDF (189 KB)  
    Freely Available from IEEE
  • Annual ISSN relaibility and maintainability symposium

    Publication Year: 2008 , Page(s): i
    Save to Project icon | Request Permissions | PDF file iconPDF (201 KB)  
    Freely Available from IEEE
  • [Copyright and reprint permission]

    Publication Year: 2008 , Page(s): ii
    Save to Project icon | Request Permissions | PDF file iconPDF (125 KB)  
    Freely Available from IEEE
  • Symposium Management Committee

    Publication Year: 2008 , Page(s): iii
    Save to Project icon | Request Permissions | PDF file iconPDF (130 KB)  
    Freely Available from IEEE
  • Past symposia & general chairs

    Publication Year: 2008 , Page(s): iv
    Save to Project icon | Request Permissions | PDF file iconPDF (137 KB)  
    Freely Available from IEEE
  • The R. A. Evans - P. K. McElroy Award for the 2007 Best Paper

    Publication Year: 2008 , Page(s): v - vi
    Save to Project icon | Request Permissions | PDF file iconPDF (382 KB)  
    Freely Available from IEEE
  • Previous recipients [The R. A. Evans ?? P. K. McElroy Award]

    Publication Year: 2008
    Save to Project icon | Request Permissions | PDF file iconPDF (159 KB)  
    Freely Available from IEEE
  • The R.A. Evans - P.K. McElroy Award for 2007 Best Paper [biography of Ralph A. Evans]

    Publication Year: 2008
    Save to Project icon | Request Permissions | PDF file iconPDF (190 KB)  
    Freely Available from IEEE
  • The R. A. Evans ?? P. K. McElroy Award for 2007 Best Paper

    Publication Year: 2008
    Save to Project icon | Request Permissions | PDF file iconPDF (139 KB)  
    Freely Available from IEEE
  • Tutorial sessions Dawn to dusk - life cycle prescriptions

    Publication Year: 2008 , Page(s): x
    Save to Project icon | Request Permissions | PDF file iconPDF (118 KB)  
    Freely Available from IEEE
  • Technical program sessions and moderators

    Publication Year: 2008 , Page(s): xi - xii
    Save to Project icon | Request Permissions | PDF file iconPDF (177 KB)  
    Freely Available from IEEE
  • Technical papers

    Publication Year: 2008 , Page(s): xiii - xvii
    Save to Project icon | Request Permissions | PDF file iconPDF (146 KB)  
    Freely Available from IEEE
  • Technical Papers.2

    Publication Year: 2008 , Page(s): xviii
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    Freely Available from IEEE
  • Author index

    Publication Year: 2008 , Page(s): xix - xxi
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    Freely Available from IEEE
  • Reliability evaluation and application for systems with different phases

    Publication Year: 2008 , Page(s): 1 - 7
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (491 KB) |  | HTML iconHTML  

    Many systems are multi-phase mission systems. During different phases, the system reliability configuration, reliability requirements and operation environment can be different. For example, some components may change from active status to standby or the system reliability configuration may change from serial to parallel. In addition to configuration changes, the system may be exposed to different stress conditions; therefore, the time to failure distribution of some components will change due to the change in stress. In general, systems that operate under different phases are considered as dynamic systems. A way to estimate the reliability and availability of such systems is needed. In this paper, a systematic procedure of applying accelerated life tests and simulation to analyze the reliability and availability of such dynamic systems is first proposed. Methods for solving both non-repairable and repairable systems are provided. For non-repairable systems, an analytical solution based on cumulative damage theory is discussed. Therefore, the exponential assumption, which is used in many existing methods, is not required in the proposed method. In addition to the analytical solution, a cumulative- damage-based simulation solution is also provided. For repairable systems, based on different scenarios in real applications, the repairable phased-mission system is classified into three categories. Because of the complexity of the problem, only simulation results are given for repairable systems. The proposed systematic procedure of applying accelerated life tests in phased-mission system analysis provides a general guideline for dealing with real-world applications. The cumulative-damage-based analytical and simulation method provide a practical and useful approach for solving phased-mission system problems. The classification of repairable phased-mission systems gives a clear overview of the phased-mission systems and makes the analysis of complex real applications eas- ier. View full abstract»

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  • A systems reliability approach to decision making in autonomous multi-platform systems operating a phased mission

    Publication Year: 2008 , Page(s): 8 - 14
    Cited by:  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (312 KB) |  | HTML iconHTML  

    This paper presents a decision making strategy for autonomous multi-platform systems, wherein a number of platforms perform phased missions in order to achieve an overall mission objective. Phased missions are defined for both single and multi-platform systems and a decision making strategy is outlined for such systems. The requirements for a tool performing such a strategy are discussed and methods and techniques, traditionally used for system reliability assessment, are identified to fulfill these requirements. Two examples are presented in order to demonstrate how a decision making tool would be employed in practice. Finally, a brief discussion of the efficient implementation of such a strategy is presented. View full abstract»

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  • Risk analysis of phased-mission systems with multiple failure modes

    Publication Year: 2008 , Page(s): 15 - 20
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (300 KB) |  | HTML iconHTML  

    General systems such as production plants and aircrafts can be regarded as a phased-mission system, which perform several different functions depending on their operation stage. This paper proposes a novel, simple and practical risk analysis method of phased mission systems with multiple failure modes. Firstly, based on the physical definition of a system accident, system accident occurrence conditions at each phase are obtained in terms of component state conditions at start/end of a phase. Evaluating component state conditions, the system accident occurrence probability can be easily evaluated. An illustrative example of a batch process in the chemical reactor shows the merits and details of the proposed method. View full abstract»

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  • Reliability analysis of phased-mission systems using Bayesian networks

    Publication Year: 2008 , Page(s): 21 - 26
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (336 KB) |  | HTML iconHTML  

    The paper presents a Bayesian networks (BN) based method to analyze the reliability of phased-mission systems (PMS). The method includes three steps. Firstly, each phase of PMS is represented by a BN framework, named phase-BN. Then, in order to express the dependences across phases, all the phase-BN are combined by (1) connecting the root nodes that represent the same component but belong to different phases, and (2) connecting the leaf nodes of the phase-BN with a new node that represents the whole PMS mission. The new constructed BN is named PMS-BN. Lastly, the reliability analysis is performed by a discrete-time BN modeling acting on PMS-BN. Two examples are used to expatiate on the proposed approach. The PMS-BN based method provides a new way to analyze PMS, especially those with dynamic phases. Further, based on PMS-BN, fault diagnoses and sensitivity analysis can be performed easily. View full abstract»

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  • Optimal highway maintenance policies under uncertainty

    Publication Year: 2008 , Page(s): 25 - 30
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (520 KB) |  | HTML iconHTML  

    We develop an inspection and maintenance policy to minimize the cost of maintaining a given section of road or highway when there is a great deal of uncertainty in the degradation process. We propose to model the degradation of a section of road based on the proliferation and growth of cracks. We utilize a combination of a Poisson and gamma process to account for the tremendous amount of uncertainty and difficulty in predicting the proliferation of cracks. Our policy defines the optimal inspection interval as well as the minimum threshold at which to perform crack repairs. Furthermore, our policy contains a safety constraint to prevent the probability of a ldquocatastrophicrdquo failure from exceeding a pre-determined reliability value. Numerical calculations have shown that our model will extend the lifecycle of the road by performing preventive, conditioned-based maintenance to slow down the growth of cracks. Classical preventive maintenance policies usually shorten the lifecycle by forcing earlier renewals. View full abstract»

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  • A study on optimal age replacement of dozer engines

    Publication Year: 2008 , Page(s): 31 - 36
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (372 KB)  

    In this paper, the concepts and methods of total time on test (TTT) plots are discussed. The failure data of two groups of electro-mechanical equipment (indigenous and imported dozer engines) are used to draw TTT plots, which indicate health of equipment in terms of failure rate. The optimum replacement interval is obtained for the equipment with increasing failure rate depending on the type of the data i.e. independently and identically distributed (i.i.d) or not. Graphical and analytical tests are used to confirm the nature and trend of the data. Non-parametric methods like Kaplan-Meir estimate and Nelson estimate are used to evaluate cumulative distribution function and scaled TTT to construct the plots. Parametric methods like Weibull and power law process models are used to verify the graphical results. View full abstract»

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  • World-class supply chain reliability in general aviation

    Publication Year: 2008 , Page(s): 37 - 41
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (254 KB) |  | HTML iconHTML  

    The overall objective of design for reliability is to ensure that the final product will be economically reliable. This means that the product's observed reliability has been established with consideration of life cycle costs. These costs include the acquisition cost, scheduled maintenance cost, unscheduled maintenance cost and the cost of failures. Cessna Aircraft Company has developed a model that is used to track the performance of each component, not only based on historical field history, but based on what matters most to the customers, the life cycle cost. This very simple model enables the design and procurement teams to evaluate options, prioritize resources and provides feedback very quickly to the design team during the design process as to which issues need to be addressed first. View full abstract»

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  • Uncertainty in Life Cycle Cost of railway track

    Publication Year: 2008 , Page(s): 42 - 47
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (319 KB) |  | HTML iconHTML  

    Life Cycle Cost (LCC) is used as a cost effective decision support for maintenance of railway track infrastructure. However, a fair degree of uncertainty associated with the estimation of LCC is due to the statistical characteristics of Reliability, Availability and Maintainability (RAM) parameters. This paper illustrates a methodology for estimation of uncertainty linked with LCC, by a combination of Design of Experiment (DoE) and Monte Carlo simulation. The paper also includes developed maintenance cost models for track and a case study of Banverket (Swedish National Rail Administration). View full abstract»

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  • A methodology for managing reliability growth during operational mission profile testing

    Publication Year: 2008 , Page(s): 48 - 53
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (367 KB) |  | HTML iconHTML  

    It is common practice for systems to be subjective to operational testing during their development program. The objective of this testing is to evaluate the performance, including reliability, of the system under conditions that represent actual use conditions. Because of expense, resources, schedule, and other considerations, these operational tests rarely represent exactly the actual use conditions. Rather, stated mission profile conditions are specific for the operational testing. These mission profiles conditions are typically general statements that guide the testing on an average basis during the testing. Because of practical constraints the elements that make up the mission profile conditions are typically tested under varying schedules with the intent that on average the mission profile conditions are met. It is also common practice that reliability corrective actions are incorporated into the system during this type of testing. That is, the test is often an operational mission profile reliability growth test. Under these conditions, we usually have a lack of structure for managing the elements that make up the mission profiles, which makes it very difficult to have an agreed-on methodology for estimating the system's reliability. This is especially true if reliability growth is occurring. Many systems fail operational testing because key assessments parameters can not be made in a straightforward clear manner so that management can take timely and appropriate action. This paper addresses this issue and presents a methodology currently being applied on major Department of Defense programs for operational reliability growth testing. View full abstract»

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  • An age-adjusted comparison of field failure data for repairable systems

    Publication Year: 2008 , Page(s): 54 - 58
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (329 KB) |  | HTML iconHTML  

    The conventional calendar-based mean cumulative function (MCF) plot is useful in monitoring the field reliability of a population of repairable systems deployed in a large quantity. It is simple and easily understood by management. However, it is age-confounded when the system population is heterogeneous with age. Assuming that the systems follow the well-known ldquoBathtubrdquo behavior, the population which consists of a higher proportion of aged systems will perform badly on the MCF plot compared to another population made up of mainly newer systems. Hence, direct comparisons between the two populations may not be fair. This paper illustrates a few simple steps that aid in mitigating such age heterogeneity issue prior to plotting the MCF. The age-adjusted MCF allows a fairer comparison of maintenance performance between the populations. The applicability of the proposed approach is demonstrated using actual field failure data. The case study shows that if differences in system age compositions are not accounted for, different conclusions could be drawn which could be detrimental to the maintenance personnel morale. Worse still, precious maintenance resources might be channeled to the wrong location. Other than age, the proposed approach can be easily extended to adjust for other system attributes. View full abstract»

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