MARC 主機 00000nam a2200445K 4500 001 AAI28028871 005 20201109125230.5 006 m o d 007 cr mn ---uuuuu 008 201109s2020 miu sbm 000 0 eng d 020 9798662568846 035 (MiAaPQ)AAI28028871 040 MiAaPQ|beng|cMiAaPQ|dNTU 100 1 Song, Changyue 245 10 Internet of Things-Enabled Degradation Modeling, Inference, and Prognosis 264 0 |c2020 300 1 online resource (171 pages) 336 text|btxt|2rdacontent 337 computer|bc|2rdamedia 338 online resource|bcr|2rdacarrier 500 Source: Dissertations Abstracts International, Volume: 82- 02, Section: B 500 Advisor: Liu, Kaibo 502 Thesis (Ph.D.)--The University of Wisconsin - Madison, 2020 504 Includes bibliographical references 520 Degradation is common in a variety of engineering systems, which can lead to system failures. Enabled by the Internet of Things technology, sensors have been widely used to monitor the degradation process of engineering systems. By analyzing the collected sensor signals, the failure time of an engineering system can be predicted, and appropriate maintenance can be scheduled to avoid unexpected failures. This brings an unprecedented opportunity for developing advanced methodologies that enable and assist (i) the efficient handling of the rich and diverse sensor measurements, (ii) the estimation and inference of the unobserved degradation status, and (iii) the exploitation of the acquired knowledge for more enhanced prognosis of the future dynamics and decision-making for predictive maintenance. This thesis focuses on Internet of Things- enabled degradation modeling, inference, and prognosis to develop data analytics methodologies by effectively combining advanced statistics, machine learning and engineering domain knowledge. The proposed methodologies enable (i) the proper and robust modeling of the degradation process and the inter-relations of the sensors, (ii) an accurate estimation of the unknown degradation status, (iii) an accurate prediction of the future behaviors and failure time, and (iv) the enactment of decisions for predictive maintenance. The first chapter introduces the background and elaborates the challenges in degradation modeling, inference, and prediction enabled by Internet of Things. The objective of this thesis is also highlighted. Chapter 2 focuses on health index methods for degradation modeling and prognostics with multiple sensor signals. While a health index is constructed by combining the multiple sensor signals to characterize the degradation process, existing health index methods are limited to linear fusion function. In this chapter, we propose a novel health index method that extends the linear fusion function to nonlinear functions by incorporating the kernel methods. Chapter 3 focuses on a more fundamental issue regarding the theoretical justification of the health index methods. Existing health index methods are heuristic, and the prognostic performance of the constructed health index cannot be guaranteed. To address this issue, we propose to use indirect supervised learning, where the failure time information is used as an indirect indicator of the underlying degradation status to guide the construction of the health index. In this way, the constructed health index is theoretically guaranteed to characterize the true degradation process. Chapter 4 further proposes a generic framework for multisensor degradation modeling, where a novel concept called failure surface is proposed to define system failure based on multiple sensor signals, and a new method is proposed to estimate the failure surface by transforming the degradation modeling problem into a classification problem. As a result, the proposed method is flexible to explore complicated relations of sensor signals, is capable of handling asynchronous signals, and can automatically screen out non-informative sensors. Chapter 5 proposes a systematic method for degradation modeling and prognosis that can be widely used in different scenarios. After extracting features for each sensor signal, local linear models are adopted to establish the relation between the extracted features and failure time. A goodness-of-fit measure is further proposed to assess the adequacy of the local linear model. If a unit is monitored by multiple sensors, decision-level fusion and feature-level fusion are further used to fuse the information from the sensors. Chapter 6 then summarizes the contributions of the thesis. In summary, this thesis contributes to the Internet of Things-enabled degradation modeling, inference, and prognosis by developing systematic data-driven analytics methodologies. The research possesses a great potential for applications in manufacturing, health care, and energy facilities, etc., where Internet of Things technology has been rapidly adopted 533 Electronic reproduction.|bAnn Arbor, Mich. :|cProQuest, |d2020 538 Mode of access: World Wide Web 650 4 Industrial engineering 650 4 Artificial intelligence 653 Internet of Things-enabled 653 Degradation modeling 653 Inference 653 Prognosis 655 7 Electronic books.|2local 690 0546 690 0800 710 2 ProQuest Information and Learning Co 710 2 The University of Wisconsin - Madison.|bIndustrial Engineering 773 0 |tDissertations Abstracts International|g82-02B 856 40 |uhttp://pqdd.sinica.edu.tw/twdaoapp/servlet/ advanced?query=28028871|zclick for full text (PQDT) 912 PQDT
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