Browsing by Subject "system"

Now showing 1 - 3 of 3
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    A Bayesian Approach to Recovering Missing Component Dependence for System Reliability Prediction via Synergy Between Physics and Data
    (ASME, 2021-11) Li, Huiru; Du, Xiaoping; Mechanical and Energy Engineering, School of Engineering and Technology
    Predicting system reliability is often a core task in systems design. System reliability depends on component reliability and dependence of components. Component reliability can be predicted with a physics-based approach if the associated physical models are available. If the models do not exist, component reliability may be estimated from data. When both types of components coexist, their dependence is often unknown, and the component states are therefore assumed independent by the traditional method, which can result in a large error. This work proposes a new system reliability method to recover the missing component dependence, thereby leading to a more accurate estimate of the joint probability density (PDF) of all the component states. The method works for series systems whose load is shared by its components that may fail due to excessive loading. For components without physical models available, the load data are recorded upon failure, and equivalent physical models are created; the model parameters are estimated by the proposed Bayesian approach. Then models of all component states become available, and the dependence of component states, as well as their joint PDF, can be estimated. Four examples are used to evaluate the proposed method, and the results indicate that the proposed method can produce more accurate predictions of system reliability than the traditional method that assumes independent component states.
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    The Dynamics of Twisted Tent Maps
    (2013-07-12) Chamblee, Stephen Joseph; Misiurewicz, Michał, 1948-; Roeder, Roland; Geller, William; Eremenko, Alexandre; Mukhin, Evgeny
    This paper is a study of the dynamics of a new family of maps from the complex plane to itself, which we call twisted tent maps. A twisted tent map is a complex generalization of a real tent map. The action of this map can be visualized as the complex scaling of the plane followed by folding the plane once. Most of the time, scaling by a complex number will \twist" the plane, hence the name. The "folding" both breaks analyticity (and even smoothness) and leads to interesting dynamics ranging from easily understood and highly geometric behavior to chaotic behavior and fractals.
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    Knowledge Management For Quality Improvement of Service Methods - A Case Study of a Laboratory Instrument
    Nierste, Michael K.; McDaniel, Anna M.
    A systematic method can extrapolate tacit knowledge (hidden or subjective knowledge) so that it can become objective and discernable. This process focused on discovering causes of failures by extricating data from medical equipment service software cases closed by telephone by field service personnel. Their responses to observed failures were compared to troubleshooting guides in use by telephone support personnel to find new processes that would increase effectiveness of telephone support staff. We asked “What are indicators of device failure reported in technical support calls?” and then “What factors contribute to user reported device failures identified by callers to technical support?” A series of interviews with veteran personnel were used to validate responses from the “phone closed” cases along with ideas pulled from a review of documentation. Analysis of one hundred seventy three cases yielded over five hundred recommendations to make the telephone support personnel’s responses more accurate, consistent and reliable.