Thesis. 1977. M.Arch.--Massachusetts Institute of Technology. Dept. of Architecture. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ROTCH. / Bibliography : leaf 58. / by Marcia K. Hnatowich. / M.Arch.

This dissertation focuses on the development of data analytics approaches to two distinct important condition monitoring applications in civil infrastructure: structural health monitoring and road surface monitoring. In the first part, measured vibration responses of a major long-span bridge are used to identify its modal properties. Variations in natural frequencies over a daily cycle have been observed with measured data, which are probably due to environmental effects such as temperature and traffic. With a focus on understanding the relationships between natural frequencies and temperatures, a controlled simulation-based study is conducted with the use of a full-scale finite element (FE) model and four regression models. In addition to the temperature effect study, the identified modal properties and the FE model are used to explore both deterministic and probabilistic model updating approaches. In the deterministic approach (sensitivity-based model updating), the regularization technique is applied to deal with a trade-off between natural frequency and mode shape agreements. Specific nonlinear constraints on mode shape agreements are suggested here. Their capabilities to adjust mode shape agreements are validated with the FE model. To the best of the author's knowledge, the sensitivity-based clustering technique, which enables one to determine efficient updating parameters based on a sensitivity analysis, has not previously been applied to any civil structure. Therefore, this technique is adapted and applied to a full-scale bridge model for the first time to highlight its capability and robustness to select physically meaningful updating parameters based on the sensitivity of natural frequencies with respect to both mass and stiffness-related physical parameters. Efficient and physically meaningful updating parameters are determined by the sensitivity-based clustering technique, resulting in an updated model that has a better agreement with measured data sets. When it comes to the probabilistic approach, the application of Bayesian model updating to large-scale civil structures based on real data is very rare and challenging due to the high level of uncertainties associated with the complexity of a large-scale model and variations in natural frequencies and mode shapes identified from real measured data. In this dissertation, the full-scale FE model is updated via the Bayesian model updating framework in an effort to explore the applicability of Bayesian model updating to a more complex and realistic problem. Uncertainties of updating parameters, uncertainty reductions due to information provided by data sets, and uncertainty propagations to modal properties of the FE model are estimated based on generated posterior samples. In the second part of this dissertation, a new innovative framework is developed to collect pavement distress data via multiple vehicles. Vehicle vibration responses are used to detect isolated pavement distress and rough road surfaces. GPS positioning data are used to localize identified road conditions. A real-time local data logging algorithm is developed to increase the efficiency of data logging in each vehicle client. Supervised machine learning algorithms are implemented to classify measured dynamic responses into three categories. Since data are collected from multiple vehicles, the trajectory clustering algorithm is introduced to integrate various trajectories to provide a compact format of information about road surface conditions. The suggested framework is tested and evaluated in real road networks.

L’objectif de cette thèse est de proposer une méthode permettant d’optimiser la stratégie de maintenance d’un système multi-composants. Cette nouvelle stratégie doit être adaptée aux conditions d’utilisation et aux contraintes budgétaires et sécuritaires. Le vieillissement des composants et la complexité des stratégies de maintenance étudiées nous obligent à avoir recours à de nouveaux modèles probabilistes afin de répondre à la problématique. Nous utilisons un processus stochastique issu de la Fiabilité Dynamique nommé processus markovien déterministe par morceaux (Piecewise Deterministic Markov Process ou PDMP). L’évaluation des quantités d’intérêt (fiabilité, nombre moyen de pannes...) est ici réalisé à l’aide d’un algorithme déterministe de type volumes finis. L’utilisation de ce type d’algorithme, dans ce cadre d’application, présente des difficultés informatiques dues à la place mémoire. Nous proposons plusieurs méthodes pour repousser ces difficultés. L’optimisation d’un plan de maintenance est ensuite effectuée à l’aide d’un algorithme de recuit simulé. Cette méthodologie a été adaptée à deux systèmes ferroviaires utilisés par la SNCF, l’un issu de l’infrastructure, l’autre du matériel roulant. / The aim of this work is to propose a methodology to optimize a multi-components system maintenance. This new maintenance strategy must be adapted to budget and safety constraints and operating conditions. The aging of components and the complexity of studied maintenance strategies require us to use new probabilistic models in order to address the problem. A stochastic process from Dynamic Reliability calculations are here established by using a deterministic algorithm method based on a finite volume scheme. Using this type of algorithm in this context of application presents difficulties due to computer memory space. We propose several methods to counter these difficulties. The optimization of a maintenance plan is then performed using simulated annealing algorithm. This methodology was used to optimize the maintenance of two rail systems used by the French national railway company (SNCF).

L’objectif de nos travaux est de mettre en place une méthode pour modéliser le comportement de la dégradation de moteurs aéronautiques à partir de données de retour d’expérience en vue de quantifier l’impact sur le niveau de sécurité des vols. Ces modèles tiennent compte d'un composant dont les mécanismes de défaillance sont en concurrence vis-à-vis d’un événement final (événement redouté rare) et de la politique de maintenance préventive. Nous souhaitons ainsi estimer la fiabilité d'un composant et étudier l'impact d'une nouvelle périodicité de maintenance sur cette fiabilité. Un algorithme d'optimisation des différentes périodicités de maintenances préventives appliquées au composant est également proposé. / The aim of our studies is to propose a statistical model of turboshaft engines ageing behaviour in order to improve the reliability level assessment. Field and repair data feedback are used to fit our model. This model takes into account one component whose failure mechanisms are in competition with respect to a final event and scheduled maintenance policy. We want to estimate reliability of engine component and, for instance, optimize the preventive maintenance policy.

Le roulement est l'un des composants les plus importants des machines tournantes. Néanmoins, dans des conditions normales d'utilisation, il est soumis à de la fatigue de roulement qui peut conduire à un défaut d'écaillage. Dans ce travail, nous présentons un suivi de la fatigue d'un roulement de butée grâce à un banc d'essais dédié. L'analyse vibratoire est une méthode qui permet de caractériser et de localiser les défauts dans les roulements. Des mesures successives de ces niveaux de vibrations donnent des indications quant à l'évolution de la sévérité des défauts. Le suivi de cette évolution est fait grâce à un indicateur statistique, la valeur RMS (Root Mean Square) qui peut être corrélée avec la taille d'un écaillage de roulement. L'approche suit le fonctionnement du roulement de butée jusqu'à la dégradation avec une acquisition on line des états vibratoires sous forme de signaux temporels. A l'aide du traitement de signal, on obtient les valeurs des amplitudes vibratoires qui caractérisent l'état vibratoire du roulement. Par conséquent, ces valeurs nous permettent de tracer les courbes de fatigue. Au cours de notre travail expérimental, cette opération est appliquée à un lot de butées à billes pour lesquelles nous avons obtenu des courbes semblables où la tendance de l'évolution suit un modèle mathématique à partir de la détection de l'apparition de la première écaille. Le résultat de ce travail contribuera à prédire la durée de vie résiduelle avant la panne. / The bearing is one of the most important components of rotating machines. Nevertheless, in normal conditions of use, it is subject to fatigue which creates a defect called a rolling fatigue spalling. In this work, we present a follow-up of the thrust bearing fatigue on a test bench. Vibration analysis is a method used to characterize the defect. In order to obtain the fatigue curve more adjusted, we have studied the vibration level according to statistical indicators: the Root Mean Square value (RMS value), which is one of the best indicators to show the evolution of the bearing degradation. The approach follows the working of the bearing until the degradation with an on line acquisition of vibration statements in form of time signals. With the signal treatment, we obtain the values of the vibration amplitudes which characterize the vibration state of the bearing. Consequently, these values allow us to plot the fatigue curves. During our experimental work, this operation is applied for a batch of thrust bearings for which we have obtained similar fatigue curves where the evolution trend follows a mathematical model from the detection of the onset of the first spall. The result of this work will contribute to predict the working residual time before failure.

Wong, Ngai Sze. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 177-190). / Abstracts in English and Chinese. / ABSTRACT --- p.I / 論文摘要 --- p.II / ACKNOWLEDGEMENT --- p.III / TABLES OF CONTENTS --- p.V / LIST OF ACRONYMS --- p.IX / LIST OF TABLES --- p.X / LIST OF FIGURES --- p.XI / LIST OF APPENDICES --- p.XIII / Chapter CHPATER 1 --- INTRODUCTION --- p.1 / Chapter 1.1. --- BACKGROUND & CONTEXT --- p.2 / Chapter 1.1.1. --- Methadone Maintenance Treatment --- p.2 / Chapter 1.1.1.1. --- Definition of Methadone Maintenance Treatment --- p.2 / Chapter 1.1.1.2. --- The Role of Methadone Maintenance Treatment --- p.3 / Chapter 1.1.1.3. --- Methadone Maintenance Treatment in Hong Kong --- p.4 / Chapter 1.1.2. --- Utilization of Methadone Treatment --- p.6 / Chapter 1.1.2.1. --- Definition of Utilization --- p.6 / Chapter 1.1.2.2. --- Utilization Study in Methadone Treatment --- p.8 / Chapter 1.1.3. --- Geographic Information System Application --- p.10 / Chapter 1.2. --- STUDY AREA --- p.12 / Chapter 1.3. --- RATIONALE & SIGNIFICANCE OF STUDY --- p.15 / Chapter 1.4. --- RESEARCH QUESTIONS --- p.17 / Chapter 1.5. --- RESEARCH OBJECTIVES --- p.18 / Chapter 1.6. --- STUDY PROCEDURES --- p.21 / Chapter 1.7. --- STRUCTURE OF THE STUDY --- p.23 / Chapter CHAPTER 2 --- LITERATURE REVIEW OF METHADONE TREATMENT UTILIZATION STUDY --- p.25 / Chapter 2.1 --- METHADONE TREATMENT UTILIZATION STUDIES --- p.26 / Chapter 2.1.1 --- Individual Determinants --- p.27 / Chapter 2.1.1.1 --- Predisposing Factors --- p.27 / Chapter 2.1.1.1 --- Enabling Factors --- p.29 / Chapter 2.1.1.2 --- Illness Level --- p.31 / Chapter 2.1.2 --- Health Service System --- p.35 / Chapter 2.1.2.1 --- Resource --- p.35 / Chapter 2.1.1.1 --- Organization --- p.36 / Chapter 2.2 --- ANALYSIS METHODS IN METHADONE TREATMENT UTILIZATION STUDIES --- p.40 / Chapter 2.2.1 --- Common Measures --- p.40 / Chapter 2.2.2 --- Study Approach --- p.41 / Chapter 2.2.3 --- Analysis Methods --- p.42 / Chapter 2.2.4 --- Geographic Information System --- p.43 / Chapter 2.3 --- METHADONE TREATMENT UTILIZATION STUDY IN HONG KONG --- p.44 / Chapter 2.4 --- SUMMARY OF LITERATURE REVIEW --- p.45 / Chapter CHAPTER 3 --- METHODOLOGY --- p.46 / Chapter 3.1. --- DEFINITION OF UTILIZATION AND LOCAL UTILIZATION --- p.47 / Chapter 3.2. --- CONCEPTUAL FRAMEWORK FOR MMT UTILIZATION --- p.50 / Chapter 3.2.1. --- Framework Selection --- p.50 / Chapter 3.2.2. --- Components of Andersen & Newman，s Framework for Health Service Utilization --- p.52 / Chapter 3.3. --- DATA SOURCE --- p.54 / Chapter 3.3.1. --- Official Data --- p.55 / Chapter 3.3.2. --- Survey --- p.56 / Chapter 3.3.3. --- Interviews --- p.57 / Chapter 3.3.4. --- Case Study-Survey in a Methadone Clinic in Tai Po --- p.57 / Chapter 3.3.4.1. --- Survey Subject --- p.57 / Chapter 3.3.4.2. --- Rationale for the Survey --- p.58 / Chapter 3.3.4.3. --- Sampling Methods --- p.59 / Chapter 3.3.4.4. --- Questionnaire Design --- p.61 / Chapter 3.3.5. --- Digitized Maps --- p.62 / Chapter 3.4. --- DATA PROCESSING AND MANAGEMENT --- p.63 / Chapter 3.4.1. --- District Utilization and Local Utilization Calculation --- p.63 / Chapter 3.4.2. --- Questionnaire Data Processing --- p.63 / Chapter 3.4.2.1. --- Data Entry & Coding --- p.63 / Chapter 3.4.2.2. --- Digitizing a GIS Layer --- p.64 / Chapter 3.4.2.3. --- Estimated Location of User Home --- p.64 / Chapter 3.4.2.4. --- Sufficiency Level --- p.67 / Chapter 3.4.3. --- Database Management --- p.68 / Chapter 3.5. --- TECHNIQUES TO ANALYZE DATA --- p.70 / Chapter 3.5.1. --- Descriptive Analysis for Spatiotemporal Utilization Pattern --- p.70 / Chapter 3.5.2. --- Quantitative Analysis for Factor Exploration --- p.70 / Chapter 3.5.2.1. --- Assumptions for Correlation and Regression Analysis --- p.70 / General Assumptions --- p.70 / Data Assumptions --- p.72 / Factor Assumptions --- p.73 / Chapter 3.5.2.2. --- Factors Included in the Study Framework --- p.74 / Societal Determinants --- p.75 / Health Services System --- p.76 / Individual Determinants --- p.78 / Chapter 3.5.2.3. --- Pearson´ةs Correlation --- p.80 / Chapter 3.5.2.4. --- Multiple Stepwise Linear Regression --- p.81 / Chapter 3.5.3. --- Quantitative Analysis for Spatial Factor Study --- p.84 / Chapter 3.5.3.1. --- Catchments --- p.84 / Chapter 3.5.3.2. --- Spatial Autocorrelation --- p.89 / Chapter 3.5.4. --- Curve Estimation --- p.90 / Chapter 3.6. --- GIS Customized Tools --- p.90 / Chapter 3.6.1. --- GIS System Literature Review --- p.90 / Chapter 3.6.2. --- Customized Tools Design --- p.92 / Chapter CHAPTER 4 --- ANALYSIS OF MMT UTILIZATION: A CASE STUDY IN HONG KONG … --- p.95 / Chapter 4.1. --- GENERAL DESCRIPTION --- p.96 / Chapter 4.2. --- HEROIN ADDICTION IN HONG KONG --- p.98 / Chapter 4.2.1. --- Spatiotemporal Pattern of Heroin Addiction --- p.98 / Chapter 4.2.2. --- Characteristics of Heroin Users in Hong Kong --- p.103 / Chapter 4.3. --- MMT USERS IN HONG KONG --- p.107 / Chapter 4.3.1. --- Characteristics of Methadone Clinics --- p.107 / Chapter 4.3.2. --- Characteristics of MMT Users --- p.108 / Chapter 4.3.2.1. --- Predisposing Factors of MMT Users --- p.108 / Chapter 4.3.2.2. --- Spatial movement of MMT user --- p.108 / Chapter 4.3.2.3. --- Clinic Environment-Gathering Place --- p.108 / Chapter 4.3.2.4. --- Unique Clinics --- p.109 / Chapter 4.3.3. --- Spatiotemporal Patterns of MMT Users --- p.110 / Chapter 4.4. --- INDIVIDUAL UTILIZATION STUDY - SURVEY IN A METHADONE CLINIC IN TAIPO --- p.114 / Chapter 4.4.1. --- Methadone Clinic Users in Tai Po --- p.114 / Chapter 4.4.2. --- Characteristics of Respondents --- p.114 / Chapter 4.4.2.1. --- Demographic Characteristics --- p.114 / Chapter 4.4.2.2. --- Utilization Level --- p.115 / Chapter 4.4.2.3. --- Spatial Factors and Distribution --- p.116 / Chapter 4.4.3. --- Factors Affecting the Utilization of Tai Po Methadone Clinic --- p.120 / Chapter 4.5. --- CATCHMENTS OF METHADONE CLINICS IN HONG KONG --- p.122 / Chapter 4.5.1. --- Voronoi polygons --- p.123 / Chapter 4.5.2. --- Network Analysis based on travel time --- p.124 / Chapter 4.5.2.1. --- Catchments of Methadone Clinic in Tai Po --- p.125 / Chapter 4.5.2.2. --- Projected Catchments for All Clinics in Hong Kong --- p.126 / Chapter 4.6. --- SPATIOTEMPORAL PATTERN AND SPATIAL RELATIONS OF MMT UTILIZATION --- p.128 / Chapter 4.6.1. --- MMT Utilization --- p.128 / Chapter 4.6.2. --- MMT Local Utilization --- p.131 / Chapter 4.6.3. --- Spatial Relations of MMT Utilization --- p.133 / Chapter 4.7. --- PREDICTORS OF MMT UTILIZATION AND LOCAL UTILIZATION --- p.134 / Chapter 4.7.1. --- Health Care Systems --- p.135 / Chapter 4.7.1.1. --- Resource --- p.135 / Operating Hours --- p.135 / Nearest clinic distance --- p.137 / Distance between a clinic and its nearest clinic in other districts --- p.138 / Chapter 4.7.1.2. --- Accessibility --- p.138 / Chapter 4.7.2. --- Individual Determinants --- p.139 / Chapter 4.7.2.1. --- Predisposing Determinants --- p.140 / Age --- p.140 / Gender --- p.140 / Education --- p.141 / Chapter 4.7.2.2. --- Behavioral Determinant´ؤInjection --- p.141 / Chapter 4.8. --- FUTURE MMT UTILIZATION IN HONG KONG --- p.143 / Chapter 4.9. --- SERVICE GAPS --- p.144 / Chapter 4.10. --- SUMMARY OF STUDY RESULTS --- p.152 / Chapter CHAPTER 5 --- DISCUSSION --- p.153 / Chapter 5.1. --- DISCUSSIONS ON THE RELEVANCE OF UTILIZATION PREDICTORS --- p.154 / Chapter 5.2. --- DISCUSSIONS ON METHADONE CLINIC CLOSURE --- p.159 / Chapter 5.3. --- RESEARCH LIMITATION --- p.164 / Chapter 5.3.1. --- Data Limitation --- p.164 / Chapter 5.3.2. --- Time & Resource Limitation --- p.165 / Chapter 5.3.3. --- Technical Limitation --- p.165 / Chapter 5.4. --- RECOMMENDATIONS --- p.167 / Chapter 5.4.1. --- Recommendations for Methadone Treatment System --- p.167 / Chapter 5.4.2. --- For the Society --- p.169 / Chapter 5.4.3. --- For Further Study --- p.172 / Chapter CHAPTER 6 --- CONCLUSION --- p.174 / BIBLIOGRAPHY --- p.177 / APPENDICES --- p.191

As paradas planejadas gerais nas indústrias papeleiras, normalmente realizadas anualmente, são fundamentais devido ao processo produtivo e estratégicas para a competitividade no setor. Face à sofisticação dos equipamentos e instalações, denotando intervenções complexas e de grande porte, altos custos e riscos potenciais de acidentes e danos ambientais, procura-se uma caracterização desses eventos como grandes empreendimentos. Esses, fazem parte da estratégia de manutenção definida para a planta fabril, sendo gerenciados pela equipe de manutenção que atua voltada a disponibilidade, confiabilidade, qualidade e produtividade. Neste sentido, este trabalho desenvolve uma sistemática de manutenção para o gerenciamento e controle das paradas planejadas gerais em processos de produção de celulose e papel, com a finalidade de facilitar e promover o sucesso na execução de todas as atividades e etapas envolvidas. Para isso, contextualiza-se o setor e as paradas planejadas; são revisados os principais conceitos, técnicas, práticas e ferramentas características à gestão da manutenção, qualidade e conhecimento; são estudadas abordagens específicas voltadas aos processos de produção contínua; é verificada uma prática empresarial do setor e; finalmente, é proposta uma sistemática fundamentada nestas pesquisas. Como principais benefícios observam-se: a sinergia entre as equipes de manutenção e operação; a valorização da manutenção na gestão do processo produtivo; a competitividade do negócio; a otimização dos recursos e as alavancagens de produtividade. / The general planned stops within the paper industries, once in the year as a rule, are due to the productive process and competitiveness strategies in that business sector. Current sofistified equipments and facilities call for complex and significant interventions. Because high costs involved and potential risks of both accidents and environmental nature damage, those events are characterized as important projects. They are part of the strategy defined for the manufacturing plant, thus being managed by the maintenance team focusing availability, reliability, quality and productivity. In view of such scenario, this paper develops a maintenance system addressing the management and control of planned stops within the cellulose pulp and paper production processes. The scope is to facilitate and promote the success when carrying out all the activities involved. Therefore, the context of the sector and planned stops is discussed; the main concepts, techniques, practices and tools specific to the management of maintenance, quality and knowledge are reviewed; approaches specific to the continuous production processes are studied; business practices within the sector are analyzed, and, finally, a systemic approach proposal is made grounded on the preceding research. The most important benefits observed were: the achievement of synergy among the maintenance and production teams; the true understanding of the maintenance value in the productive process; the business competitiveness; resources optimization as well as productivity boosting.

The economic implications of equipment failure are called for effective maintenance techniques. The research investigates current maintenance practice in several New Zealand industries and the improvements that could be obtained by the use of predictive maintenance techniques. Initial research was undertaken in a series of case studies within New Zealand industries situated in Auckland. The first two cases studies were of preventative maintenance techniques of two conveyor lines in a biscuit manufacturing company. The results showed a well defined preventive maintenance schedules that was Systems Applications Products (SAP) programme was used to managed for daily, weekly, monthly and yearly maintenance activities. A third case study investigated current predictive maintenance technique involving Fast Fourier Transform analysis of shaft vibration to identify a bearing defect. The results diagnosed a machine with a ball bearing defect and recommendation was given to change the bearing immediately and install new one. The machine was opened up, a big dent was on one of the balls as predicted by the analysis and the bearing was changed. Research then looked at a novel technique called Cepstrum analysis that al lows the deconvolution of vibration spectra from separate sources. This allows identification of several defects from the monitoring of a single vibration signal . Experiments were carried out to generate transfer functions for different gear faults at two different loadings. Blind deconvolution of the signal using a homomorphic filter was used to separate the source forcing frequencies from the structure resonance effects of the two gear faults, indicating that the technique could be used successfully to monitor equipment for a range of gear faults occurring simultaneously.

The objective of this project was to evaluate methods to remediate a wood I-joist with a single, circular hole in the web while leaving utilities in place. The methods were experimentally evaluated with a full-scale bending test using four equally spaced point loads. There were three depths of joists with varying flange widths and two span lengths (4.88 m & 2.44 m). Failure modes for the long span joists without holes were in the flanges in either tension, compression or lateral buckling; but once a hole was introduced the majority were classified as shear failures. Effectiveness of the remediation was evaluated based on three criteria: strength, stiffness, and ease of installation/cost. The OSB collar patch was effective for 8 out of the 12 series tested. A maximum reduction of load from a joist with no hole to one with a hole was 49% for the long span and 58% for the short span. The OSB collar was not as effective in returning stiffness to the joists, but was easier to install and less expensive than the LSL patch. / Graduation date: 2013

No description available.