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Reliability and Maintainability Symposium, 1999. Proceedings. Annual

Date 18-21 Jan. 1999

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Displaying Results 1 - 25 of 72
  • 1999 Annual Reliability and Maintainbility Symposium [front matter]

    Publication Year: 1999 , Page(s): i - x
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    Freely Available from IEEE
  • Annual Reliability and Maintainability. Symposium. 1999 Proceedings (Cat. No.99CH36283)

    Publication Year: 1999
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    Freely Available from IEEE
  • Author index

    Publication Year: 1999 , Page(s): xvii - xviii
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    Freely Available from IEEE
  • PANEL: Advisory Board - What Are The Successful Companies Doing?

    Publication Year: 1999 , Page(s): 219 - 223
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    Freely Available from IEEE
  • Author index

    Publication Year: 1999 , Page(s): cx
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    Freely Available from IEEE
  • Accelerated reliability tests: solder defects exposed

    Publication Year: 1999 , Page(s): 43 - 49
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1596 KB)  

    This paper describes methodology to perform risk assessment and establish the quality and reliability of solder joints utilizing accelerated reliability life testing techniques. Temperature cycling tests were performed on equal number of 100-pin quad flat pack package mounted on printed circuit board assemblies from a reworked and nonreworked soldering process. The data showed that the accelerated reliability tests exposed the latent defects inherent in reworked solder joints. The projected field failure rate and the percentage of reworked solder joints failures of the total PCBs shipped was high and unacceptable to meet the products MTBF target View full abstract»

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  • Equivalence relations within the failure mode and effects analysis

    Publication Year: 1999 , Page(s): 352 - 357
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (516 KB)  

    The reliability and maintainability community has long sought ways to improve the value of the FMEA as a means to influence the final design during early development stages. In addition to eliminating unacceptable single-point failures, provisions for fault detection and fault isolation (FD/FI) provide the most significant areas where the design can be influenced by the FMEA. The most recent gains in this area have been process based. J.B. Bowles' (see Proc. Annual Reliability and Maintainability Symposium, Anaheim, CA, USA, IEEE, p.48-53, 1998) inclusion of a functional FMEA prior to completion of the preliminary design moves the analysis to the beginning of the product development cycle to verify requirements prior to commencing with the detail design. This process change becomes even more significant when this initial analysis can be reused to verify the detail design. This paper examines the mathematical concept of equivalence relations and partitions within the FMEA to (1) influence the FD/FI design, (2) enable the reuse of functional analysis in the subsequent interface and piece part analyses, and (3) improve the quality and cost of the analysis. Set algebra is applied to partition all failure modes and their consequences into disjoint subsets known as fault equivalence classes. Equivalence classes are created as a method for managing all failure mode consequences View full abstract»

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  • Reliability management and engineering in a commercial computer environment

    Publication Year: 1999 , Page(s): 323 - 329
    Cited by:  Papers (1)
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    The TandemTM Division of Compaq Computers has developed a highly effective reliability program for the commercial computer industry. The program diligently applies reliability principles throughout the design, manufacture and field use of our products. Our process establishes reliability goals that, in turn, drive change and improved product reliability. We have enhanced not only the reliability of the assemblies that we design, but also the reliability of those purchased from outside suppliers. We have developed an effective field reliability data collection and analysis process that allows us to measure the increase in reliability and identify potential future problems. We have impacted the design by providing analyses that optimize cost while achieving the high system availability that our customers expect. The evidence of the effectiveness of our efforts comes through the field data that shows decreased failure rates and sustained high levels of customer satisfaction View full abstract»

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  • Aging in electronic systems

    Publication Year: 1999 , Page(s): 293 - 299
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (684 KB)  

    Aging and wearout are timely topics for today's economy. Worldwide financial conditions have forced process plant managers to use electronic control systems long beyond their design life. Process industry management has had a reputation for frugality. When capital investments are considered it is usually easier to make do with existing equipment than to defend the expenditure of capital on new equipment. This fiscal conservatism has presented the author with the opportunity to survey electronic control systems in more than 20 process plants, ranging from chemical plants in South Africa, to refineries in Texas and to power plants in Saskatchewan. This paper records the findings of those surveys, adds to the body of literature on aging and wearout in electronics, and makes engineering generalizations that can he applied to similar kinds of systems, such as personal computers View full abstract»

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  • Systematic approach to modern corded telephone early commutation failure analysis

    Publication Year: 1999 , Page(s): 84 - 90
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1296 KB)  

    Typical early failures of modern corded telephones characterized by their inability to provide correct commutation were analyzed. Specifics of advanced mass consumer communication electronics reliability and failure analysis have been discussed. Complementary theoretical and experimental methods were applied in order to effectively evaluate dialing reliability specifics, allocate defects and reveal their root causes. A regular fault tree analysis procedure has been employed, however its limitation is discussed. Results of the telephony early failure analysis related to open and short circuits of flexible flat ribbon cables and printed circuit boards, dialing button dimensions, mechanical assembly tolerance and soldering, and keypad contamination are presented. Various fault interactions were found to be major contributors to failure aggravation. A major part of observed early dialing failures was related to coarse mechanical and electro-chemical causes rather than to subtle component or material degradation. Recommendations for corrective action were developed View full abstract»

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  • System reliability analysis of an embedded hardware/software system using fault trees

    Publication Year: 1999 , Page(s): 135 - 141
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (568 KB)  

    The use of fault trees allows for the unified modeling of embedded hardware/software systems. Fault trees can also produce a sensitivity analysis to provide insight as to which hardware and software components are potentially the most problematic for a given system. From this analysis, the effects that the various hardware and software components have on the overall system reliability can be quantified. Using an example system, it is demonstrated that the various software components contained within a system have a significant impact on the overall system reliability. Hence, software and hardware must be integrated in the reliability analysis of embedded systems to properly represent system behavior and to properly predict the overall system reliability View full abstract»

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  • A new method for obtaining the TTT plot for a censored sample

    Publication Year: 1999 , Page(s): 112 - 117
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (576 KB)  

    For a censored sample where withdrawns or suspensions are present, Kaplan-Meier-estimation (KME) method, also called product-limit-estimation (PLE) method, and piecewise-exponential-estimation (PEXE) method, have been typically used to estimate both the survivor function (or cdf) and the total time on test (TTT) statistic at each observed failure time. This paper presents a new method, called mean-order-number (MON) method, for estimating TTT statistics and TTT plot for a censored sample. This method is illustrated using Dodson's example as quoted by numerous authors. A comparison is made among MON, KME, and PEXE. It turns out that MON method is not only easy to use but its results are consistent with KME and PEXE as well View full abstract»

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  • An algorithm to partition the operational availability parts of an optimal provisioning strategy

    Publication Year: 1999 , Page(s): 310 - 316
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (480 KB)  

    The implementation of an appropriate and cost-effective sparing provisioning strategy depends on the choice of an adequate mathematical model. The model chosen should provide optimal cost-effective provisioning as well as other applicable factors and should emphasize the following aspects for a total system evaluation: (i) identification of system parameters, and (ii) interactions of system parameters for optimal evaluation. The different parts that make up the system operational availability (AO) must be identified. If an algorithm could be developed to represent the different parts of AO , the individual contributions of these could be identified and used to determine an optimal provisioning strategy or other factors that influence the overall operational availability. From the basic RMA (reliability, maintainability, availability) concepts, analytical derivations, and empirical example, an algorithm can be used to express the operational availability as a function of all its parts. The mathematical model developed to partition ail of the individual availabilities of the system AO is a simple and direct way to use the calculated values of the individual availabilities. By partitioning system operational availability into all its parts, it can be easily evaluated, trade studies can be made, and it can be optimized for a cost-effective provisioning strategy. This paper presents an algorithm that makes it possible to partition easily, directly, and concisely by using the already calculated individual availabilities View full abstract»

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  • Failure assessment software for circuit card assemblies

    Publication Year: 1999 , Page(s): 269 - 276
    Cited by:  Papers (4)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1232 KB)  

    Up-front failure analysis of circuit card assembly designs can dramatically reduce cost of ownership, increase product reliability, and thus reduce risks. In this paper, the design process for electronic products is discussed in terms of failure assessment activity. Information resources necessary to support the failure assessment activity are discussed. Finally, the effectiveness of failure assessment software is demonstrated by analyzing circuit card assemblies (CCAs) from a military radio control module using the calcePWA software developed by the CALCE Electronic Products and Systems Center (EPSC) at the University of Maryland View full abstract»

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  • Experience in using MEADEP

    Publication Year: 1999 , Page(s): 158 - 164
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (784 KB)  

    This paper reports some of the authors' experience in using MEADEP-a newly developed measurement-based dependability evaluation tool that includes both data analysis and modeling functions. Several issues are discussed: identification of time between outages and time to repair distributions; need for more graphical model forms; and consistency between parameter estimation and model evaluation algorithms. The identified distribution functions are valuable for detailed analysis and realistic modeling. The significance of discovering the inconsistency between the failure rate estimation and the availability evaluation algorithms is not limited to only MEADEP because both algorithms are commonly used. The need for more graphical model forms and the demand for better user interfaces are driving improvements for MEADEP. These issues provide insights into the roles and future directions for this kind of tools View full abstract»

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  • A Bayes approach for uncertainty bounds for a stochastic analysis of the Space Shuttle main engine

    Publication Year: 1999 , Page(s): 7 - 12
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    In this paper a Bayesian approach was presented to derive a time-dependent parametric probability function of a sudden critical structural failure of the Space Shuttle Main Engine Block I design, including uncertainty bounds at any given time. The probability function was assumed to have a Weibull form with parameters β and η. Under this assumption, both prior belief about this type of failure (based on a component based analysis) and the information available from the complex test data set of the SSME were used as input for the Bayesian update. The test data contains both actual failures and tests that were stopped before failure (`censored'), which made the process of examining the data set a challenging endeavor. The outcome of the Bayesian update formed the posterior belief in the parameters of the probability function. It was concluded that under the assumption of a Weibull distribution for a sudden critical structural failure, the uncertainty about the parameters is strongly diminished by combining the prior belief with the test data View full abstract»

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  • Investigation of reliability of hydraulic-robots for hazardous environments using analytic redundancy

    Publication Year: 1999 , Page(s): 122 - 128
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (544 KB)  

    The Rosie mobile worksystem is a robot that is on the cutting edge of hazardous environment robotics. It is a heavy-duty hydraulic robot designed for nuclear reactor decontamination and dismantlement. The robot consists of a wheeled platform containing a central hydraulic power supply powered by an electric tether, four independently steerable wheels, and a heavy-duty crane/manipulator. The hydraulic wheel actuator subsystem has been determined to be a vital component of the mobile platform through reliability analysis. Our research into analyzing this robot's reliability through the technique of analytical redundancy (AR) will help provide the Department of Energy (DOE) with a more complete and effective set of tests for monitoring and diagnostics of the Rosie system. In this paper, we discuss the derivation through AR of a suite of model based tests for the default sensor package for one of Rosie's wheel actuators. AR allows us to exploit the sensor information of the sensors values and the system model to derive tests of the consistency of the sensor data. Some of these tests are comparison of the actual system response to control inputs to predicted response indicated by the model, the other tests uncovered by the AR analysis reflect higher order state interdependencies. These tests and their use in monitoring and diagnostics for Rosie are detailed and examined in depth. This work is also an interesting example of the application of model based techniques for an important class of practical systems View full abstract»

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  • Frequently asked questions about rocket engine reliability programs

    Publication Year: 1999 , Page(s): 343 - 351
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (720 KB)  

    The objective of the Atlas Reliability Enhancement Program (AREP) was to improve the reliability of the Atlas IIA Launch Vehicle without degrading its performance. This objective was achieved by developing an electronically enhanced rocket engine, the Pratt & Whitney (P&W) RL1OE-1, for the Centaur Upper Stage. Less than three years after AREP began, the USAF terminated the program halfway through the test phase of the second developmental engine. Even though the program ended before a single RL10E-1 engine was shipped, a legacy of lessons learned were indwelled in the experiences of the individuals who participated in the program. AREP was the first DoD launch vehicle program to operate under the new Acquisition Reform Initiative, which went into effect in June 1994. Under Acquisition Reform, acquisition processes are supposed to be based on measurable performance criteria. However, not every organization that participates in the development of a new system knows how to define a measurable performance criterion. That was the challenge facing Lockheed Martin Astronautics (LMA) when it came time to implement a process to manage AREP Reliability risk. Knowing what LMA did for AREP provides insight for others wishing to define a performance-based reliability program. This paper is based on a technical report written by The Aerospace Corporation. The information in this paper is structured in a manner that facilitates communicating valuable lessons learned that are comprehensible to the novice and useful to the expert View full abstract»

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  • Bayesian analysis for system reliability inferences

    Publication Year: 1999 , Page(s): 151 - 157
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (532 KB)  

    Due to declining defense budgets, operational test and evaluation programs for military systems have been down-one significant result is less system operational test data. This leads to lower classical confidence inferences on critical measures of performance such as system reliability. This paper explores the use of Bayesian methods to compensate for this decrease in test data by integrating developmental test and evaluation data into the operational test and evaluation phase. Specifically, the reliability of a series system, a parallel system and a classic bridge system are examined over a range of mission times. Components in this study are assumed to have exponential lifetimes. Using simulated data for the three systems, the Bayesian methods produce tighter probability intervals for the system reliability than the confidence intervals found through classical inference methods View full abstract»

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  • System reliability modeling considering the dependence of component environmental influences

    Publication Year: 1999 , Page(s): 214 - 218
    Cited by:  Papers (2)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (456 KB)  

    A system reliability modeling procedure is described and demonstrated to accommodate the case when component failure times are statistically correlated because of the shared environmental exposure of components within a system. When component failure times are correlated, independence assumptions are not valid, and thus, many common reliability modeling practices are inappropriate. If component reliability is influenced by environmental exposure, then the components within a system are likely to have correlated time-to-failures because all components within a system are influenced similarly by the system-level environmental stress profile. This scenario is often overlooked when failure data is analyzed for a homogeneous population of parts that have experienced nonhomogeneous usage profiles. The model presented here is based on proportional hazards models for component reliability and discretized approximation of the joint probability density function for system environmental stress variables. The discretization approach is mathematically convenient, accurate and offers several pragmatic advantages over alternative computation approaches. A hypothetical three-component series system is analyzed, and the results are compared to two common approximations: (1) component independence assumption and (2) use of environmental stress average values. The results indicate that the described approach is convenient and has the potential to be scaled-up to large problems View full abstract»

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  • Reliability analysis of Torino Sud district heating system

    Publication Year: 1999 , Page(s): 336 - 342
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (540 KB)  

    The system consists of two heat production plants (for a total of 621 MW). a branched closed circuit transportation network, a distribution network and heat exchange substations. AEM wants to modify the district heating system anticipating a growth of user connection; for this reason different system solutions were studied. The object of this study is to evaluate the better solution according to a cost-benefit analysis. The costs are represented by the necessary investments to realise each change; the benefits are represented in terms of reliability growth for Torino Sud district heating system and the decrease of the consequences (user out of service) in case of faults in the system. Then availability and expected number of failures of the system were determined via a fault tree analysis related to the top event “no heat to user for t>1 hour”. The consequences of faults for each macro-component of the system were defined as a function of the users out of service and a risk-map of whole system was made. Finally new availability analysis were made analysing four different solutions for the system in order to find the best one. The results of the reliability analysis of the system in the present configuration are satisfactory: the availability is in a range of 97.36% and 99.73%. The mission time is 1 year (8760 hours of continuous operation) and the expected number of failures for a year is in a range of 0.98 and 9.81 View full abstract»

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  • Uncertainty considerations in compliance-testing for electromagnetic interference

    Publication Year: 1999 , Page(s): 265 - 268
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (412 KB)  

    Product assurance aims at manufacturing and marketing products that meet the requirements of the customer and the regulatory authorities, thus meeting the requirements of society at large. This involves manufacturing, testing and certification of the product. Thus the product assurance actually involves the manufacturers, testing laboratories, certification bodies directly and standardisation bodies, regulatory authorities indirectly. The compliance or otherwise of a product to its technical specification is judged based on compliance criteria: the regulatory requirements refer to technical specifications. The product characteristics vary due to inherent variability in the manufacturing process. The evaluation of the product characteristics in the manufacturing organisation or testing laboratories involves measurements and there is an uncertainty factor associated with measurement results. The compliance decision has to take the uncertainty factors into consideration. The paper describes how these factors have been considered for judging compliance for electromagnetic interference/electromagnetic compatibility (EMI/EMC) and safety View full abstract»

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  • A design language for automatic synthesis of fault trees

    Publication Year: 1999 , Page(s): 91 - 96
    Cited by:  Papers (1)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (552 KB)  

    The separation of digital system design and reliability analysis incurs unnecessary costs, delays and quality penalties. This paper introduces a graphical design language called RIDL (Reliability Information embedded Design Language) for modeling digital systems. In RIDL, redundancy and failure information is embedded within block diagram schematics, without significantly altering the physical block diagram models typically used by design engineers. A system schematic in RIDL has all of the information needed for reliability analysis without a need for additional textual descriptions. A dynamic fault tree model can be automatically synthesized from a RIDL system model. Designers can use the synthesized fault trees to obtain rough reliability analyses at an early conceptual design stage. To evaluate the potential of this approach, we have applied it to several example systems View full abstract»

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  • A modified FMEA tool for use in identifying and addressing common cause failure risks in industry

    Publication Year: 1999 , Page(s): 19 - 24
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (568 KB)  

    The nature of common cause failures (CCFs) is explored in the context of existing analytical techniques. Failure modes and effects analysis (FMEA) is described as a means for accomplishing early risk assessment in the context of an existing analysis framework. Cause and coupling factor taxonomies are refined to fit the FMEA methodology. This modification allows consideration of CCF risks. Blending this methodology with the standard FMEA process enables a seamless prioritization of single failure and CCF risks for further studies and actions. An example is provided to illustrate the use of this new tool View full abstract»

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  • Improving the manufacturing test interval and costs for telecommunication equipment

    Publication Year: 1999 , Page(s): 410 - 417
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (632 KB)  

    Generally, most circuit packs of telecommunication systems are processed through a manufacturing test process that may include in-circuit test, functional test, factory environmental stress testing or environmental stress screening (ESS), and system tests. Some of these tests, like ESS, may also be due to customer or Bellcore requirements. However, it is both expensive and time consuming to process all production circuit packs through all these tests, particularly when the test yields in some of these tests are close to 100 percent, and the field reliability performance is much better than expected. In this paper, we describe an approach for developing sampling plans for performing these tests. We feel that this approach of using production sampling plans in manufacturing coupled with statistical analysis of factory test yield and field reliability data to identify the best circuit pack candidates, can be applied to any large production volume telecommunication system for reducing both the manufacturing test interval and costs View full abstract»

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