14 research outputs found

    Reliability Abstracts and Technical Reviews January - December 1970

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    Reliability Abstracts and Technical Reviews is an abstract and critical analysis service covering published and report literature on reliability. The service is designed to provide information on theory and practice of reliability as applied to aerospace and an objective appraisal of the quality, significance, and applicability of the literature abstracted

    Theory and design of reliable spacecraft data systems

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    Theory and techniques applicable to design, analysis, and fault diagnosis of reliable spacecraft data system

    Batch Control and Diagnosis

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    Batch processes are becoming more and more important in the chemical process industry, where they are used in the manufacture of specialty materials, which often are highly profitable. Some examples where batch processes are important are the manufacturing of pharmaceuticals, polymers, and semiconductors. The focus of this thesis is exception handling and fault detection in batch control. In the first part an internal model approach for exception handling is proposed where each equipment object in the control system is extended with a state-machine based model that is used on-line to structure and implement the safety interlock logic. The thesis treats exception handling both at the unit supervision level and at the recipe level. The goal is to provide a structure, which makes the implementation of exception handling in batch processes easier. The exception handling approach has been implemented in JGrafchart and tested on the batch pilot plant Procel at Universitat Politècnica de Catalunya in Barcelona, Spain. The second part of the thesis is focused on fault detection in batch processes. A process fault can be any kind of malfunction in a dynamic system or plant, which leads to unacceptable performance such as personnel injuries or bad product quality. Fault detection in dynamic processes is a large area of research where several different categories of methods exist, e.g., model-based and process history-based methods. The finite duration and non-linear behavior of batch processes where the variables change significantly over time and the quality variables are only measured at the end of the batch lead to that the monitoring of batch processes is quite different from the monitoring of continuous processes. A benchmark batch process simulation model is used for comparison of several fault detection methods. A survey of multivariate statistical methods for batch process monitoring is performed and new algorithms for two of the methods are developed. It is also shown that by combining model-based estimation and multivariate methods fault detection can be improved even though the process is not fully observable

    Inferential stability in systems biology

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    The modern biological sciences are fraught with statistical difficulties. Biomolecular stochasticity, experimental noise, and the “large p, small n” problem all contribute to the challenge of data analysis. Nevertheless, we routinely seek to draw robust, meaningful conclusions from observations. In this thesis, we explore methods for assessing the effects of data variability upon downstream inference, in an attempt to quantify and promote the stability of the inferences we make. We start with a review of existing methods for addressing this problem, focusing upon the bootstrap and similar methods. The key requirement for all such approaches is a statistical model that approximates the data generating process. We move on to consider biomarker discovery problems. We present a novel algorithm for proposing putative biomarkers on the strength of both their predictive ability and the stability with which they are selected. In a simulation study, we find our approach to perform favourably in comparison to strategies that select on the basis of predictive performance alone. We then consider the real problem of identifying protein peak biomarkers for HAM/TSP, an inflammatory condition of the central nervous system caused by HTLV-1 infection. We apply our algorithm to a set of SELDI mass spectral data, and identify a number of putative biomarkers. Additional experimental work, together with known results from the literature, provides corroborating evidence for the validity of these putative biomarkers. Having focused on static observations, we then make the natural progression to time course data sets. We propose a (Bayesian) bootstrap approach for such data, and then apply our method in the context of gene network inference and the estimation of parameters in ordinary differential equation models. We find that the inferred gene networks are relatively unstable, and demonstrate the importance of finding distributions of ODE parameter estimates, rather than single point estimates

    Fragment / Part / Whole: Matter and Mediality in Michael Landy’s Break Down

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    This thesis investigates Break Down by Michael Landy (2001), in which the artist’s 7227 belongings were systematically catalogued, dismantled and granulated. Break Down, it is argued, opens up alternative modes of engaging with materiality and mediality; this thesis explores an array of related concerns arising from the work. Landy’s process of fragmentation elicits an inquiry into concepts of part and whole, single and multiple. The granulated material produced during Break Down provokes an account, via Deleuze and Guattari’s concept of affect, of the fragment as narrative matter. Further, Break Down is considered in terms of its operations between the textual and the material. With reference to Friedrich Kittler’s account of media as distributed and multilateral entities, this text explores the conventions pertaining to two textual forms deployed by Landy in relation to Break Down; the instruction manual and the inventory. Finally, Landy’s father’s sheepskin coat, the final object to be shredded during Break Down, is the fulcrum for an appraisal of the thing as an extension of personhood, and of human subjectivity as in some sense ‘thingly’. In this text, Break Down is constructed as an assemblage that operates at the intersection of a complex, mobile massing of currents and specificities; a framing that informs both the structure and the methodology of this thesis. Written, photographic and audio-visual source material is deployed here alongside close analysis of two important texts published by Landy in 2001 as accompaniments to Break Down itself: Michael Landy / Break Down, and Break Down Inventory. In addition, drawing upon Jane Rendell’s strategy of ‘site writing,’ passages of close observational writing are used intermittently throughout this text to relay what might in Deleuzo-Guattarian terms be called the becoming of the texts and subjects under discussion

    Energy: A special bibliography with indexes, April 1974

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    This literature survey of special energy and energy related documents lists 1708 reports, articles, and other documents introduced into the NASA scientific and technical information system between January 1, 1968, and December 31, 1973. Citations from International Aerospace Abstracts (IAA) and Scientific and Technical Aerospace Reports (STAR) are grouped according to the following subject categories: energy systems; solar energy; primary energy sources; secondary energy sources; energy conversion; energy transport, transmission, and distribution; and energy storage. The index section includes the subject, personal author, corporate source, contract, report, and accession indexes

    Safety and Reliability - Safe Societies in a Changing World

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    The contributions cover a wide range of methodologies and application areas for safety and reliability that contribute to safe societies in a changing world. These methodologies and applications include: - foundations of risk and reliability assessment and management - mathematical methods in reliability and safety - risk assessment - risk management - system reliability - uncertainty analysis - digitalization and big data - prognostics and system health management - occupational safety - accident and incident modeling - maintenance modeling and applications - simulation for safety and reliability analysis - dynamic risk and barrier management - organizational factors and safety culture - human factors and human reliability - resilience engineering - structural reliability - natural hazards - security - economic analysis in risk managemen

    Control of a navigationg rational agent by natural language

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