To see the other types of publications on this topic, follow the link: Computers, maintenance and repair.
Dissertations / Theses on the topic 'Computers, maintenance and repair'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Computers, maintenance and repair.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Luyt, Leslie. "Automated grid fault detection and repair." Thesis, Rhodes University, 2012. http://hdl.handle.net/10962/d1006693.
Full textAbstract:
With the rise in interest in the field of grid and cloud computing, it is becoming increasingly necessary for the grid to be easily maintainable. This maintenance of the grid and grid services can be made easier by using an automated system to monitor and repair the grid as necessary. We propose a novel system to perform automated monitoring and repair of grid systems. To the best of our knowledge, no such systems exist. The results show that certain faults can be easily detected and repaired.TeX
Adobe Acrobat 9.51 Paper Capture Plug-in
2
Toves, Peter Rocky. "Evaluating Success Factors in Implementing E-Maintenance in Maintenance, Repair, and Overhaul (MRO) Organizations." ScholarWorks, 2015. https://scholarworks.waldenu.edu/dissertations/767.
Full textAbstract:
Despite more than a decade-long process to transition aircraft maintenance practices from paper-to electronic-based systems, some organizations remain unable to complete this transition. Researchers have indicated that while organizations have invested resources in technology improvements, there remains a limited understanding of the factors that contribute to effectively managing technology-enabled change. The purpose of this case study was to identify and explore socio-technical (ST) factors that inhibit an effective transition from a paper-based system to an electronic-based system for aircraft maintenance. A conceptual model applying theories of change management, technology acceptance, systems thinking, and ST theory informed the research. Thirteen participants provided data via semistructured interviews, field observations, follow-up interviews, other documentation, and a questionnaire. Data were analyzed with open and axial coding techniques to identify themes, which were then crosschecked and triangulated with observation and follow-up interview data. Findings revealed communication issues, a fundamental misconception in training, and a false assumption that all personnel easily acquire computer literacy. Benefits gained from this study should assist maintenance, repair, and overall (MRO) organizations within the Department of Defense to improve current and future technology implementation as the research underscores real-life issues from a comparable organization. The implications for positive social change provide a greater understanding of technology-enabled change and contribute to the development of best practices for technology initiatives that address common ST issues in the MRO workplace.
3
Yang, Ling. "Nodes failure detection in large scale network." Thesis, The University of Sydney, 2005. https://hdl.handle.net/2123/27923.
Full textAbstract:
It is the age of information technology. Around the world, millions of computers
are being linked together in networks of all sizes, from small local area
networks to giant enterprise wide area networks. This rapid growth means a lot
of opportunity for people working or preparing to work, in the computer
industry.
In today’s world of LANs and WANs, almost all business depends on
internetworking for data communication. From the world wide internet to
private intranet, internetworking technology is present in virtually every aspect
of a business technical operation. And in this age of information technology it is
very important to discover network failure as soon as possible.
in this project, we present a set of methods to detect network nodes failure and
predict network nodes failure with failure reasons. We describe the design and
implementation by using a resource-combined algorithm, Nai've Bayes
Classifier and Bayes Network.
Results show that with the resource-combined algorithm the performance of
actual nodes failure detection can be improved. Results also show that
network nodes failure can be predicted in a fixed time before actual failure with
a high degree of accuracy.
4
Doyle, Leo F. "A guide for the selection and maintenance of computer peripherals." Virtual Press, 1991. http://liblink.bsu.edu/uhtbin/catkey/834517.
Full textAbstract:
This thesis is a resource document for computer information that is not presently available as a single unit. It describes most of the commonly available computer peripherals and some not-so-common ones from the micro, mini, and mainframe computer worlds. Physical descriptions, methods of operation, trouble shooting, maintenance, and some schematics and future trends are covered. A few older devices having historical significance are also discussed.By knowing where the computer industry is currently and seeing where it has been hardware-wise, it should be possible to project the direction in which the computer industry is headed. People in the computer profession and people that use computers need to be educated about peripheral devices so that they may make informed decisions on which equipment to acquire and in planning for the future. This thesis should be a valuable aid in this process. The information presented should save time and money during the decision-making process and lead to more effective choices of equipment.Department of Computer Science
5
Eastwood, Grant. "Using computer vision to categorize tyres and estimate the number of visible tyres in tyre stockpile images." Thesis, Nelson Mandela Metropolitan University, 2017. http://hdl.handle.net/10948/16022.
Full textAbstract:
Pressures from environmental agencies contribute to the challenges associated with the disposal of waste tyres, particularly in South Africa. Recycling of waste tyres in South Africa is in its infancy resulting in the historically undocumented and uncontrolled existence of waste tyre stockpiles across the country. The remote and distant locations of such stockpiles typically complicate the logistics associated with the collection, transport and storage of waste tyres prior to entering the recycling process. In order to optimize the logistics associated with the collection of waste tyres from stockpiles, useful information about such stockpiles would include estimates of the types of tyres as well as the quantity of specific tyre types found in particular stockpiles. This research proposes the use of computer vision for categorizing individual tyres and estimating the number of visible tyres in tyre stockpile images to support the logistics in tyre recycling efforts. The study begins with a broad review of image processing and computer vision algorithms for categorization and counting objects in images. The bag of visual words (BoVW) model for categorization is tested on two small data sets of tread tyre images using a random sub-sampling holdout method. The categorization results are evaluated using performance metrics for multiclass classifiers, namely the average accuracy, precision, and recall. The results indicated that corner-based local feature detectors combined with speeded up robust features (SURF) descriptors in a BoVW model provide moderately accurate categorization of tyres based on tread images. Two feature extraction methods for extracting features for use in training neural networks (NNs) for tyre count estimations in tyre stockpiles are proposed. The two feature extraction methods are used to describe images in terms of feature vectors that can be used as input for NNs. The first feature extraction method uses the BoVW model with histograms of oriented gradients (HOG) features collected from overlapping sub-images to create a visual vocabulary and describe the images in terms of their visual word occurrence histogram. The second feature extraction method uses the image gradient magnitude, gradient orientation, and edge orientations of edges detected using the Canny edge detector. A concatenated histogram is constructed from individual histograms of gradient orientations and gradient magnitude. The histograms are then used to train NNs using backpropogation to approximate functions from the feature vectors describing the images to scalar count estimations. The accuracy of visible object count predictions are evaluated using NN evaluation techniques to determine the accuracy of predictions and the generalization ability of the fit model. The count estimation experiments using the two feature extraction methods for input to NNs showed that fairly accurate count estimations can be obtained and that the fit model could generalize fairly well to unseen images.
6
Phung, Quoc V. "Survivability through pre-configured protection in optical mesh networks." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2005. https://ro.ecu.edu.au/theses/665.
Full textAbstract:
Network survivability is a very important issue, especially in optical networks that carry huge amount of traffic. Network failures which may be caused by human errors, malfunctional systems and natural disaster (eg. Earthquakes and lightening storms), have occurred quite frequently and sometimes with unpredictable consequences. Survivability is defined as the ability of the network to maintain the continuity of service against failures of network components. Pre-configuration and dynamic restoration are two schemes for network survivability. For each scheme, survivability algorithms can be applied at either Optical Channel sublayer (Och) known as link-based. Or, Optical Multiplex Section sublayer (OMS) known as path-based. The efficiency of survivability algorithms can be assessed through such criteria as capacity efficiency, restoration time and quality service. Dynamic restoration is more efficient than pre-configuration in terms of capacity resource utilization, but restoration time is longer and 100% service recovery cannot be guaranteed because sufficient spare capacity may not be available at the time of failures. Similarly, path-based survivability offers a high performance scheme for utilizing capacity resource, but restoration time is longer than link based survivability.
7
Weppenaar, De Ville. "Intelligent maintenance management in a reconfigurable manufacturing environment using multi-agent systems." Thesis, Bloemfontein : Central University of Technology, Free State, 2010. http://hdl.handle.net/11462/136.
Full textAbstract:
Thesis (M. Tech.) -- Central University of Technology, Free State, 2010Traditional corrective maintenance is both costly and ineffective. In some situations it is more cost effective to replace a device than to maintain it; however it is far more likely that the cost of the device far outweighs the cost of performing routine maintenance. These device related costs coupled with the profit loss due to reduced production levels, makes this reactive maintenance approach unacceptably inefficient in many situations. Blind predictive maintenance without considering the actual physical state of the hardware is an improvement, but is still far from ideal. Simply maintaining devices on a schedule without taking into account the operational hours and workload can be a costly mistake. The inefficiencies associated with these approaches have contributed to the development of proactive maintenance strategies. These approaches take the device health state into account. For this reason, proactive maintenance strategies are inherently more efficient compared to the aforementioned traditional approaches. Predicting the health degradation of devices allows for easier anticipation of the required maintenance resources and costs. Maintenance can also be scheduled to accommodate production needs. This work represents the design and simulation of an intelligent maintenance management system that incorporates device health prognosis with maintenance schedule generation. The simulation scenario provided prognostic data to be used to schedule devices for maintenance. A production rule engine was provided with a feasible starting schedule. This schedule was then improved and the process was determined by adhering to a set of criteria. Benchmarks were conducted to show the benefit of optimising the starting schedule and the results were presented as proof. Improving on existing maintenance approaches will result in several benefits for an organisation. Eliminating the need to address unexpected failures or perform maintenance prematurely will ensure that the relevant resources are available when they are required. This will in turn reduce the expenditure related to wasted maintenance resources without compromising the health of devices or systems in the organisation.
8
Collins, Fred C. "Evaluation of a repairable equipment population system and its logistics support subsystem." Thesis, This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-10062009-020124/.
Full text
9
Hu, Feng-Ming. "Integrated Apartment Management System." CSUSB ScholarWorks, 2006. https://scholarworks.lib.csusb.edu/etd-project/3004.
Full textAbstract:
The Integrated Apartment Management System (IAMS) is a web-based system that allows tenants to make appointments with repairmen on line and notify both apartment managers and repairmen of appointments through an email directly from IAMS. IAMS also keeps a database of appointments, repairs, and payments that can be accessed by tenants, repairmen, and apartment managers.
10
Korn, Dennis Raymond. "The development of a student-initiated, teacher-guided hypermedia program for automotive computer control systems." CSUSB ScholarWorks, 1997. https://scholarworks.lib.csusb.edu/etd-project/1469.
Full textAbstract:
To provide a proper amount of quality training for tomorrow's automotive technicians, it will be necessary to provide more time for training or to develop a more efficient means of training. This project uses a HyperCard-based program to provide a starting point in increasing efficiency in instructional delivery and to continue to provide the skills necessary for a student to become a competent automotive technician.
11
Al-kaabi, Hamad A. "Airlines' maintenance, repair and overhaul (MRO) configurations." Thesis, Cardiff University, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.437225.
Full text
12
Bridges, Michael R. "Optimally funding Army Installation repair and maintenance activities." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1997. http://handle.dtic.mil/100.2/ADA341063.
Full textAbstract:
Thesis (M.S. in Operations Research) Naval Postgraduate School, September 1997."September 1997." Thesis advisor(s): Robert F. Dell. Includes bibliographical references (p. 43-44). Also available online.
13
Nikou, Vasilios 1972. "Welded repair and maintenance in the space environment." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/91796.
Full textAbstract:
Thesis (Nav.E.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2003.Includes bibliographical references (leaves 73-75).
by Vasilios Nikou.
Nav.E.
S.M.
14
Kelly, Annette. "Comparative analysis of intermediate level maintenance repair process." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2002. http://library.nps.navy.mil/uhtbin/hyperion-image/02Jun%5FKelly.pdf.
Full text
15
Adé, Kémy. "Kupffer Cell Maintenance in Tissue Repair and Ageing." Electronic Thesis or Diss., Sorbonne université, 2021. http://www.theses.fr/2021SORUS312.
Full textAbstract:
Les cellules de Kupffer (KCs) sont les macrophages résidents du foie. Phagocytes professionnels, ils sont au cœur du système immunitaire inné, première ligne de défense de l’organisme contre les agressions. Ils participent également au maintien de l’homéostasie tissulaire. Des travaux récents ont permis de comprendre leur origine. On sait maintenant que, à l’instar de la majorité des macrophages résidant dans les tissus, les KCs émergent durant la vie embryonnaire à partir des précurseurs érythro-myeloïdes (EMP), colonisent le foie durant le développement et y persistent à l’âge adulte. Cependant, en cas d’inflammation, ils sont rejoints par des macrophages différenciés à partir des monocytes circulants descendants des cellules souches hématopoïétiques. J’ai étudié la capacité des KCs à persister tout au long de la vie, y compris chez des souris gériatriques. En utilisant la cytométrie en flux et des techniques de traçage de lignées, j’ai montré que la densité des KCs diminuait avec l’âge sans compensation par les monocytes circulants. Un séquençage ARN, l’analyse de mutants TicamLPS2 et des expériences d’inflammation répétées induites par un analogue viral ont mis en lumière le possible rôle de l’inflammation dans ce phénotype. Ce dernier corrélait avec des altérations fonctionnelles. L’étude de la persistance des KCs dans un modèle de lésion aiguë du foie induite par le paracétamol et après déplétion des KCs par un antagoniste du récepteur CSF1R a montré que les KCs étaient capables de persister ou se reconstituer sans contribution de la circulation. Ces expériences établissent des outils pour une caractérisation des fonctions des KCs en contexte pathologiqueKupffer cells (KCs) are resident macrophages of the liver. Professional phagocytes of the innate immune system, they take part in the first line of defence against infections and injury. They also actively regulate liver homeostasis. Recent works have elucidated their origin. We now know that, like most other tissue resident macrophages, KCs develop during embryonic life from Erythro-Myeloid Progenitors (EMPs), seed the liver during development and persist there in adulthood. During inflammation, however, they can be joined by recently differentiated macrophages that arise from circulating monocytes belonging to the Haematopoietic Stem Cell (HSC) descendance. Here I studied the ability of mouse KCs to maintain themselves throughout life, and into old age. Using flow cytometry and fate mapping strategies, we showed that KC density decreased over time and was not compensated by recruitment of circulating cells. RNA sequencing, analysis of TicamLPS2 mutants and Poly (I:C)-induced repeated inflammation experiments highlighted the contribution of inflammation to the ageing phenotype. This phenotype correlated with lipid and senescent cell accumulation. We further studied KC maintenance in acetaminophen induced liver injury and after depletion induced by a CSF1R antagonist. In both contexts, KCs were able to maintain themselves through local proliferation without significant input from circulating cells. These experiments will provide a framework for the better characterisation of KC functions in injury and disease
16
Huang, He. "Case-based expert system using wavelet packet transform and kernel-based feature manipulation for engine spark ignition diagnosis." Thesis, University of Macau, 2010. http://umaclib3.umac.mo/record=b2148260.
Full text
17
Gamede, Cyril Vuyani. "Boiler maintenance using expert systems." Master's thesis, University of Cape Town, 1989. http://hdl.handle.net/11427/18798.
Full textAbstract:
This research explores the application of expert systems to the maintenance of boilers, are as follows: and its main objectives [1] To explore the application of expert systems in the maintenance of boilers. [2] To simplify the task of boiler maintenance with the help of expert systems. [3] To improve the skills of boiler maintenance workers through the knowledge 'captured ' or 'preserved' by expert systems. [4] To minimise errors which may cost time, money, effort and possible risk of injury to boiler maintenance personnel. [5] To develop a prototype expert system which can advise and assist boiler maintenance personnel. [6) To contribute to research in the application of expert systems in the field of engineering.
18
De, Wet Vorster Hendrik. "An analysis of the effectiveness of the asset maintenance plan at Spoornet : case study : class diesel locomotives (traction and rolling stock)." Thesis, Peninsula Technikon, 2001. http://hdl.handle.net/20.500.11838/1019.
Full textAbstract:
Thesis (MTech (Business Administration))--Peninsula Technikon, 2001Maintenance of locomotives is the main function of Bellville Locomotive Traction Depot in the Western Cape. Therefore, it is important to have a sound maintenance plan in place, to prevent a negative impact on the availability and reliability of locomotive supply for hauling power to train services. The purpose of the research is to determine the causes of the increased frequency of maintenance through a case study relating to 35-class locomotives. The abnormal increased frequency of wheel change and inter-bogie control repairs on 35-class diesel locomotives is investigated. A research survey was adopted, which included questionnaires and personal interviews based on the literature search. The target group is L&N section, which includes below-deck maintenance, overhaul and change out, repairs to locomotive bogies, frames, wheels, snubbers, inter-bogie control and traction motors. Sixteen people are responsible for all below-deck repairs and service of 52 locomotives. The results of the research will expose the shortcomings of the maintenance plan and propose solutions. This will be achieved by testing the effectiveness of the existing maintenance plan at Spoornet through the identification of the causes for the abnormal increase in wheel changes and inter-bogie control repairs on 35-class diesel locomotives. The outcome from this case study research will be to quantify the benefits arising from the effective application of a maintenance plan.
19
An, Wei 1963. "Strengthening of concrete beams with composite plastic plates." Thesis, The University of Arizona, 1990. http://hdl.handle.net/10150/277246.
Full textAbstract:
This study investigates the feasibility of strengthening reinforced concrete beams with epoxy-bonded Glass-Fiber-Reinforced-Plastic (GFRP) plates. The composite plate is epoxy-bonded to the tension flange of the beam to increase its stiffness and strength. Seven rectangular and one T-beam, retrofitted with composite plates, were tested to failure under symmetrical 4-point bending. The load versus deflection and the load versus strain in the composite plate, steel rebar and the extreme compression fiber of concrete were measured and plotted for the midspan section throughout the entire range of loading up to failure. Analytical models based on the equilibrium of forces and compatibility of deformations were developed to predict the stresses and deformations of the beam in the linear and nonlinear regions. The predicted and measured results correlated well. The analytical models were used in a parametric study to investigate the effects of design variables such as, plate area, plate strength and stiffness, reinforcement ratio, etc., on the moment-curvature relationships of typical rectangular and T cross sections.
20
Haidvogel, Robert F. "The Afloat maintenance Command: organizational and funding issues in Navy ship maintenance, repair, and modernization." Thesis, Monterey, California. Naval Postgraduate School, 1992. http://hdl.handle.net/10945/23521.
Full textAbstract:
Approved for public release; distribution is unlimitedThe goal of current Navy surface ship maintenance and repair strategy is to sustain readiness and to maximize both combat capability and the amount of time ships are available for employment during their lifetime. The established organizational framework of the Navy to perform this task includes a complex array of activities that are effective overall, but at the expense of efficiency. The current drawdown in budget resources requires that the goals of ship maintenance and modernization be met with improved efficiency. The Afloat Maintenance Command is a proposal to restructure the existing maintenance hierarchy. Improvements in the process of maintenance and modernization are incorporated in the Afloat Maintenance Command through the elimination of redundancies in capabilities and the improvement of funding flows to enhance organizational efficiency and effectiveness. This thesis will provide an overview of the Afloat Maintenance Command and its possible organization in consolidating assets from existing maintenance activities. Additionally, funding alternatives for the Afloat Maintenance Command will be developed and assessed.
21
盧英明 and Ying-ming Lo. "Analysis of maintenance service figures of domestic towngas appliance." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1991. http://hub.hku.hk/bib/B31976645.
Full text
22
Iu, Lai-ling. "Slope mainteannce [i.e. maintenance] and repair works in Hong Kong." Click to view the E-thesis via HKU Scholars Hub, 2005. http://lookup.lib.hku.hk/lookup/bib/B37935392.
Full text
23
Aman, Shah Shahani. "System level airborne avionics prognostics for maintenance, repair and overhaul." Thesis, Cranfield University, 2016. http://dspace.lib.cranfield.ac.uk/handle/1826/11844.
Full textAbstract:
The aim of this study is to propose an alternative approach in prognostics for
airborne avionics system in order to enhance maintenance process and aircraft
availability. The objectives are to analyse the dependency of avionic systems
for fault propagation behaviour degradation, research and develop methods to
predict the remaining useful life of avionics Line Replaceable Units (LRU),
research and develop methods to evaluate and predict the degradation
performances of avionic systems, and lastly to develop software simulation
systems to evaluate methods developed.
One of the many stakeholders in the aircraft lifecycle includes the Maintenance,
Repair and Overhaul (MRO) industry. The predictable logistics process to some
degree as an outcome of IVHM gives benefit to the MRO industry.
In this thesis, a new integrated numerical methodology called ‘System Level
Airborne Avionic Prognostics’ or SLAAP is developed; looking at a top level
solution in prognostics. Overall, this research consists of two main elements.
One is to thoroughly understand and analyse data that could be utilised.
Secondly, is to apply the developed methodology using the enhanced
prognostic methodology.
Readily available fault tree data is used to analyse the dependencies of each
component within the LRUs, and performance were simulated using the linear
Markov Model to estimate the time to failure. A hybrid approach prognostics
model is then integrated with the prognostics measures that include
environmental factors that contribute to the failure of a system, such as
temperature. This research attempts to use data that is closest to the data
available in the maintenance repair and overhaul industry.
Based on a case study on Enhanced Ground Proximity Warning System
(EGPWS), the prognostics methodology developed showed a sufficiently close
approximation to the Mean Time Before Failure (MTBF) data supplied by the Original Equipment Manufacturer (OEM). This validation gives confidence that
the proposed methodology will achieve its objectives and it should be further
developed for use in the systems design process.
24
Lia, Debora. "Role of alphaOGG1 in the Maintenance of Mitochondrial Physiology." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS125/document.
Full textAbstract:
Les mitochondries sont des structures uniques dans la cellule mammifère. Ces organites portent leur propre génome (ADN mitochondrial, ADNmt) qui se compose d'une petite molécule qui codifie pour 13 polypeptides de la chaîne de transport d'électrons (ETC), 22 ARNt et 2 gènes d'ARNr pour sa propre synthèse protéique. Le MTDNA est proposé pour être plus susceptible au stress oxydatif que le génome nucléaire (ADNn) parce que non seulement il manque d'histones protectrices, mais aussi en raison de sa proximité avec les complexes ETC qui sont les principaux producteurs de ROS dans les cellules de mammifères. Parmi tous les types de dommages à l'ADNmt, les dommages oxydatifs sont les plus répandus et, de loin, les mieux étudiés. La voie de réparation de l'excision de base (BER) est un mécanisme de réparation d'ADN conservé de façon évolutive qui répare les dommages de base d'ADN non volumineux. Puisque la guanine a le potentiel redox le plus bas de toute autre base dans l'ADN, elle est facilement oxydée à la 8-oxoguanine (8-oxoG) qui est l’altération la plus fréquente induite par les ROS sur les deux, l'ADNc et l'ADNmt. Si la fourche de réplication contourne le 8-oxoG avant son élimination, un A est souvent inséré sur le brin d'ADN opposé et les réplications subséquentes corrigent la transversion de G à T. Lorsqu'il est associé à la cytosine, le 8-oxoG est éliminé de l'ADN par l'ADN glycosylase de 8-oxoguanine (OGG1) qui, de cette manière, initie le procédé BER. OGG1 est une glycosylase de ménage bi fonctionnelle qui, conjointement avec d'autres enzymes BER différentes, est présente dans les compartiments nucléaires et mitochondriaux, soulignant l'importance de maintenir l'intégrité de l'ADNmt pour le fonctionnement cellulaire normal. Il a été démontré que la surexpression d'une version recombinante d'OGG1, spécifiquement destinée aux mitochondries par un signal de ciblage mitochondrial supplémentaire (MTS) (OGG1-MTS), protège les cellules d'un stress oxydatif, probablement en raison d'une efficacité accrue dans la réparation De 8-oxoG dans l'ADNmt. L'objectif principal de notre projet est d'élucider si la perte spécifique de l'activité de réparation 8-oxoG dans les mitochondries (mais pas dans le compartiment nucléaire) a un impact sur les fonctions organelles et / ou sur la viabilité cellulaire et aussi pour dévoiler le mécanisme / s Derrière les effets protecteurs d'OGG1 sur la physiologie mitochondriale et la maintenance d'ADNmtMitochondria are unique structures within the mammalian cell. These organelles carry their own genome (mitochondrial DNA, mtDNA) which consists of a small molecule that codifies for 13 polypeptides of the electron transport chain (ETC), 22 tRNA and 2 rRNA genes for its own protein synthesis. MtDNA is proposed to be more susceptible to oxidative stress than the nuclear genome (nDNA) because not only it lacks protective histones but also because of its proximity to ETC complexes which are the main ROS producers in mammalian cells. Among all the types of mtDNA damage, oxidative damage is the most prevalent and, by far, the best studied. Base excision repair (BER) pathway is an evolutionarily conserved DNA repair mechanism that repairs non-bulky DNA base damages. Since guanine has the lowest redox potential of any other bases in DNA, it is readily oxidized to 8-oxoguanine (8-oxoG) that is the most frequent alteration induced by ROS on both, nDNA and mtDNA. If the replication fork bypasses the 8-oxoG before its removal, an A is often inserted on the opposite DNA strand and subsequent replications fix the G to T transversion. When paired with cytosine, 8-oxoG is removed from DNA by the 8-oxoguanine DNA glycosylase (OGG1) that in such a way initiates the BER process. OGG1 is a bifunctional housekeeping glycosylase that, together with other various BER enzymes is present in both nuclear and mitochondrial compartments, highlighting the importance of maintaining mtDNA integrity for normal cellular functioning. It has been demonstrated that the overexpression of a recombinant version of OGG1, specifically targeted to mitochondria by an additional Mitochondrial Targeting Signal (MTS) (OGG1-MTS), protects the cells from an oxidative stress, likely due to an increased efficiency in the repair of 8-oxoG in mtDNA. The main goal of our project is to elucidate if the specific loss of 8-oxoG repair activity in mitochondria (but not in nuclear compartment) has an impact on the organelles’ functions and/or on cell viability and also to unveil the mechanism/s behind the protective effects of OGG1 on mitochondrial physiology and mtDNA maintenance
25
Oliveira, Leonardo Presoto de. "Uma abordagem interativa para auxiliar no diagnóstico automotivo." Universidade Tecnológica Federal do Paraná, 2017. http://repositorio.utfpr.edu.br/jspui/handle/1/3133.
Full textAbstract:
Fundação Araucária de Apoio ao Desenvolvimento Científico e Tecnológico do ParanáEste trabalho tem como objetivo desenvolver uma abordagem para auxiliar as montadoras na obtenção de informações sobre os problemas e falhas que ocorrem nos veículos durante o seu uso pelos motoristas, relacionando os dados obtidos com a leitura da telemetria do veículo, assim como as percepções do motorista sobre uma determinada falha. A exploração de técnicas que auxiliam o diagnóstico automotivo é um problema a ser discutido na engenharia. As técnicas de diagnóstico devem fornecer suporte à grande gama de sistemas que surgirão nos próximos anos. Assim, é possível também utilizar a conectividade que os celulares e veículo dispõem na atualidade, com o intuito de evoluir o produto oferecido e melhorar a experiência do cliente enquanto dirige. A inclusão do cliente no processo de diagnóstico, visa permitir que os projetistas identifiquem pontos que podem ser melhorados no carro, mesmo que não apresentem erro aparente. A opinião do cliente pode ser considerada, uma vez que ele é incluído no processo como um novo “sensor" (o mais inteligente e importante de todos) capaz de reportar suas percepções. Considerando este fato, a motivação deste trabalho se encontra em: (i) Procurar alternativas para aplicar de maneira eficiente a conectividade dos veículos no processo de diagnóstico; (ii)Permitir que as montadoras possam obter informações mais concretas dos veículos que comercializam. O objeto é fornecer um sistema de interface entre o usuário e o carro auxiliando a realização dos diagnósticos preventivos mais completos do que apenas usando a telemetria. Neste projeto busca-se que haja uma interação maior com o motorista, e que a experiência das montadoras possa entrar no processo de diagnóstico. Mesmo que o cliente não tenha tanta intimidade com o funcionamento do veículo, o sistema deve orientar o motorista no processo. A entrada de dados do cliente é realizada por texto ou comando de voz. Para a análise desta entrada de dados do cliente foi realizado um estudo de mineração de dados em bases que a montadora já possuía. Estas bases são entrevistas telefônicas nas quais a montadora pergunta ao cliente problemas percebidos no carro, e então as respostas são transcritas para a base. O estudo de mineração de dados foi realizado para a criação do classificador que é responsável por receber os dados de entrada do cliente e classifica-lo em um determinado problema ligado à multimídia ou relacionado ao motor do veículo. O software contido no celular será responsável por solicitar ao sistema de sensores do veículo as leituras necessárias para que o cliente obtenha as informações que deseja. Foi realizado um experimento no qual analistas de diagnóstico responderam a um questionário que buscava analisar se o sistema proposto realmente influenciava no processo de diagnóstico, fazendo com que a solução dos problemas no veículo seja realizada em menos etapas, se comparado com o processo atual. Os resultados mostraram que a abordagem diminuiu o número de etapas necessárias para a obtenção do diagnóstico correto. Dos três estudos de caso realizados, as etapas necessárias para se chegar ao diagnóstico apropriado diminuiu em uma etapa para o primeiro estudo de caso, diminuiu uma etapa para o segundo estudo de caso, e três etapas a menos para o terceiro estudo de caso. Com estes resultados foi possível demonstrar que a abordagem proposta influiu no processo de diagnóstico aplicado atualmente pelas montadoras e concessionárias analisadas.
The goal of this project is to develop an approach to assist automakers in obtaining information about the problems and failures that occur in the vehicles during their use by drivers, relating the data obtained by reading the telemetry of the vehicle, as well as the perceptions of the driver about a particular failure. The exploration of techniques to optimize automotive diagnosis is a problem to be discussed in Engineering. Diagnostic techniques should support the wide range of systems that will emerge in the coming years. Thus, it is also possible to use the connectivity that mobile phones and vehicles have today, in order to evolve the product offered and improve the customer experience while driving. The customer inclusion in the diagnostic process aims to allow engineers identifies points to be improved in the car, even if they dont present an apparent error. The customer opinion should be considered, since he/she is included in the process as a new "sensor"(the most intelligent and important of all) able to report his/her perceptions. Considering this fact, the motivation of this research is: (i) search for alternatives to efficiently apply vehicle connectivity in the diagnostic process, (ii) enable automakers to obtain more concrete information on the vehicles they sell. The object is provide an interface between the user and the car helping them to perform a more complete preventive diagnoses than only using telemetry. In this project it is sought that there is a greater interaction with the driver, and the experience of the automakers could be included the diagnostic process. Even if the customer isnt so accustomed with the operation of the vehicle, the system must guide the driver by the process. The customer input data is performed by text or voice command. The analysis of this customer input data, a data mining study was performed based on a base that automaker already had. These bases are telephone interviews in which the automaker asks the customer for perceived problems in the car, and then the answers are transcribed to the base. The data mining study was performed to create one classifier which was responsible for receiving the input data from the customer and sorting it into a particular problem related with the multimídia or related to the motor of the vehicle. The software contained in the mobile phone will be responsible asking to the vehicle sensor system for the readings necessary for the customer can to obtain the information he/she wants. An experiment was carried out in which diagnostic analysts answered a questionnaire that sought to analyze whether the proposed system actually influenced the diagnostic process, so the solution of the problems in the vehicle was performed on less steps compared to the current process. The results showed the approach reduced the number of steps required to obtain the correct diagnosis. Of the three case studies performed, the steps required to arrive at appropriate diagnosis decreased in one step to the first case study, one step to the second case study decreased, and three less steps to the third case study . With these results it was possible to demonstrate that the proposed approach influenced the diagnostic process currently applied by the automakers and concessionaires analyzed.
26
Nguyen, Hai Hoang. "Truth maintenance in knowledge-based systems." Thesis, University of Nottingham, 2014. http://eprints.nottingham.ac.uk/28434/.
Full textAbstract:
Truth Maintenance Systems (TMS) have been applied in a wide range of domains, from diagnosing electric circuits to belief revision in agent systems. There also has been work on using the TMS in modern Knowledge-Based Systems such as intelligent agents and ontologies. This thesis investigates the applications of TMSs in such systems. For intelligent agents, we use a “light-weight” TMS to support query caching in agent programs. The TMS keeps track of the dependencies between a query and the facts used to derive it so that when the agent updates its database, only affected queries are invalidated and removed from the cache. The TMS employed here is “light-weight” as it does not maintain all intermediate reasoning results. Therefore, it is able to reduce memory consumption and to improve performance in a dynamic setting such as in multi-agent systems. For ontologies, this work extends the Assumption-based Truth Maintenance System (ATMS) to tackle the problem of axiom pinpointing and debugging in ontology-based systems with different levels of expressivity. Starting with finding all errors in auto-generated ontology mappings using a “classic” ATMS [23], we extend the ATMS to solve the axiom pinpointing problem in Description Logics-based Ontologies. We also attempt this approach to solve the axiom pinpointing problem in a more expressive upper ontology, SUMO, whose underlying logic is undecidable.
27
Yearby, Shedrick Dashun. "USMC Aviation Maintenance and Repair Cost for the H-1 Upgrade." Thesis, Monterey, California. Naval Postgraduate School, 2012. http://hdl.handle.net/10945/6891.
Full textAbstract:
MBA Professional ReportApproved for public release, distribution unlimited
This research focuses on the Marine Corps Aviation Maintenance and Repair Cost for the H-1 Upgrade platform. Onsite visits with the Program Manager Air 276 (PMA-276), the Naval Supply Weapons Systems Support (NAVSUP WSS), the Defense Logistics Agency (DLA), and Marine Aviation Logistics Squadron 39 (MALS-39) are conducted to obtain information regarding readiness costs and efficiencies that have impacted the total cost for a transitioning aircraft in Marine aviation. PMA-276, NAVSUP WSS, DLA, and MALS-39 make up the H-1 Cross-Functional Team (CFT). The H-1 CFT provides actionable metrics and best practices that focus on cost concerns (programmatic, material, management, and execution) from all levels of aviation logistics and planning. Key areas of improvement or replication are identified through metric-based solutions that affect cost reductions throughout the AH-1Z and UH-1Y integration.
28
Wood, Thomas L. "Evaluation of project selection techniques for pavement network maintenance and repair." Thesis, Monterey, California. Naval Postgraduate School, 1994. http://hdl.handle.net/10945/25909.
Full textAbstract:
Different approaches have been suggested for determining the optimal
mix of repair projects for a pavement network. These methods range from
random selection to sophisticated mathematical optimization models.
This paper presents an analysis of several questions regarding the
effectiveness of three possible selection methods.
First, the performance of three separate single year project selection
methods on different size networks is assessed over a broad funding spectrum.
The results indicate that as funding levels increase, the benefit obtained by
different selection methods converge. In addition, as the size of the network
increases, the convergence tends to occur at progressively lower funding levels.
Second, the effect of the performance prediction models on these same
selection methods is assessed by altering the coefficients of the models to predict both faster and slower deterioration of the network. The "select sets" of
projects created by priority ranking selection and Knapsack IP selection at three
separate funding levels are compared to determine how much variation is introduced by the changes in the performance prediction. With a 30%
acceleration and deceleration of the deterioration curves, there was little change
in the optimal project set created by either method.
Finally, a modified Monte Carlo model is used to assess the general
shape of the solution space. The results suggest that the solution space is relatively flat except in the immediate vicinity of the optimum. This, in turn,
suggests that a Monte Carlo approach to this problem would require a large
number of trials to approximate the optimum. This finding conceptually supports
findings in this study and others, as well as the intuitive observation, that random
maintenance and repair strategies perform poorly compared to more rational
approaches. Since only a few sets of repair projects are near the optimum, the
chances of a random selection matching one of these near optimal project sets are relatively small.
29
Coxon, W. D. "Evaluation of models for decision making in inspection and repair maintenance." Master's thesis, University of Cape Town, 1987. http://hdl.handle.net/11427/21151.
Full textAbstract:
There has been growth in the costs of maintenance over the last 40 years. This can be linked directly to the changes in production technology over that period of time. However. there has also been growth in the field of management science and operations research. Many models have been developed to assist the maintenance function in its decisions. However. it would appear from engineering journals and shop floor practice that these models are not well used. For this research the method of inspection and repair maintenance has been chosen. Mainly because it is one of the most widely used methods. The objectives of the research are as follows: (1) To investigate the state of the art of plant and equipment maintenance paying particular attention to the inspection and repair policy. (2) To establish what basic models are available for decision making in inspection and repair maintenance. (3) To establish how feasible and useful each of these models is in the practical engineering environment. (4) To consider factors in the implementation of a decision making model in the inspection and repair policy with particular reference to the most practical and feasible model investigated.
30
Konda, Issa 1962. "Tractor repair and maintenance costs and management policies in Burkina Faso." Thesis, The University of Arizona, 1991. http://hdl.handle.net/10150/277842.
Full textAbstract:
Farm machinery management data were collected in Burkina Faso, for the prediction of repair and maintenance costs. Equations were developed to predict repair and maintenance costs of tractors, cane loaders, generators and motorpumps. The analysis of data revealed that tractor repair and maintenance appears a greater burden than predicted by the American and Australian data. Tractor trade-in was not prescribed by the rule of minimum total cost per unit tractor use. Farm machinery and power units were operated more than twice as long as in the United States. New machine purchase was discouraged by the current sugar prices on the local market.
31
Toledo, Maria Luiza Guerra de. "Determination of the optimal periodic maintenance policy under imperfect repair assumption." Universidade Federal de Minas Gerais, 2014. http://hdl.handle.net/1843/BUOS-9KRG8A.
Full textAbstract:
An appropriate maintenance policy is essential to reduce expenses and risks related to repairable systems failures. The usual assumptions of minimal or perfect repair at failures are not suitable for many real systems, requiring the application of Imperfect Repair models. In this work, the classes Arithmetic Reduction of Age and Arithmetic Reduction of Intensity, proposed by Doyen and Gaudoin (2004) are explored. Likelihood functions for such models are derived, and the parameters are estimated, allowing to compute reliability indicators to forecast the future behavior of the failure process. Under the classic Imperfect Repair virtual age model presented by Kijima et al. (1988) (particular case of Aithmetic Reduction of Age class), a periodic Preventive Maintenance policy is proposed, which estimates optimal time intervals for Preventive Maintenance, in order to minimize (preventive and corrective) maintenance costs. Under a dynamic perspective, it is showed how this policy can be improved, using each failure observation in order to recalculate the optimal time to Preventive Maintenance for a particular system, considering the effect of the repair action. These policies are applicable to any Imperfect Repair model. Monte Carlo simulation studies are implemented in order to evaluate the performance of the proposed methods. Those methods are applied to a real situation regarding the maintenance of engines of off-road trucks used in a mining company. These results bring valuable information to support decision making regarding Preventive Maintenance policy..
32
Peterson, Reginald E. "Exploring Customers' Perceptions of Third Party Maintenance, Repair, and Operating Programs." ScholarWorks, 2016. https://scholarworks.waldenu.edu/dissertations/2170.
Full textAbstract:
A survey of 25 industrial manufacturing organizations in the U. S. indicated that 70% of respondents experienced dissatisfaction with their outsourcing programs due to unfulfilled expectations, which caused negative continuance intentions. The purpose of this descriptive case study was to explore the experiences of customers who currently use 3PMRO outsourcing programs to determine what factors affect satisfaction levels in the Southern United States. The conceptual framework for this study was the expectancy disconfirmation paradigm, which connects consumer satisfaction level to the fulfillment of consumer expectations. Data were collected from interviews of 22 procurement professionals of maintenance, repair, and operating supplies; observations of 3PMRO supplier performance meetings; and the analysis of performance scorecard documents. Data were analyzed using pattern matching followed by thematic analysis. Three themes were identified through the data analysis that affected consumer satisfaction: inventory management services, utilization of outsourced labor resources, and total cost value of the 3PMRO program. According to results, satisfaction of 3PMRO consumers are based on the proper utilization of a 3PMRO program for the intended limitations of the organization, reduced MRO supply costs, improved inventory management strategies, and improved competitive advantage from the realignment of resources to focus on core competencies. Implications for positive social change include increased awareness of cradle-to-grave inventory management to prevent improper disposal of non-biodegradable materials into our environment.
33
Barnhart, Cynthia. "Investigation of need for organized maintenance." Virtual Press, 1986. http://liblink.bsu.edu/uhtbin/catkey/450777.
Full textAbstract:
The benefits of maintenance have been known for centuries, and throughout history these benefits have been the basis for much discussion. Recently such benefits have been formally proposed in terms of scheduled or cyclical maintenance programs. These programs have been developed for important historic buildings; yet the same benefits can be applied to any house. This concept is the basis of this thesis.The thesis begins with a discussion of the obvious need for some maintenance program and describes the recent interest of local governments in some form of maintenance planning, discussing the benefits of an organized approach to maintenance. Next it briefly reviews the beginnings and history of maintenance theories and is followed by a discussion of maintenance as a level of conservation of building. Basic statistics about homeowners and the development of the survey are addressed, which leads to the presentation of compiled results of the survey and a interpretation of the data. The conclusion indicates a direction for the development of an organized maintenance plan.
34
Vorthmann, Scott A. "Syntax-directed editor support for incremental consistency maintenance." Diss., Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/9241.
Full text
35
Haddad, Fadi M. "Maintenance in a contractor organization:a practical approach." Thesis, Virginia Tech, 1989. http://hdl.handle.net/10919/44641.
Full textAbstract:
A model for optimizing the assignment of maintenance actions for a piece of equipment
is developed in the thesis. The model considers the detectability and the criticality of
component failure in order to assign a maintenance instruction. The thesis also develops
the framework for an integrated maintenance management system. The system consists
of three modules. The first module is work control. It is used to prepare, schedule, and
insure the execution of maintenance instructions. The second module is the equipment
condition control module which monitors maintenance effectiveness and accordingly
updates the maintenance instructions. The third module is cost control. This is the tool
used to monitor the economical performance of the maintenance function. An equipment
information system is also presented, and two futuristic maintenance proposals are
introduced.
The model and the integrated maintenance management system, constitute a strong tool,
that equipment managers can use to optimize the maintenance function, and improve
the mechanical, operational, and economical performance of equipment.
Master of Science
36
Limbachiya, Mukeshchandra K. "Assessment of the long term performance of repaired reinforced concrete." Thesis, Sheffield Hallam University, 1995. http://shura.shu.ac.uk/19962/.
Full textAbstract:
Rational decisions about cost-effective maintenance and structural repair are hampered by the absence of comprehensive data on structural performance of generic repair materials acting compositely with deteriorated concrete elements. In the present climate of durability problems in concrete construction such information is of critical importance. In order to assess long-term structural performance of repaired elements, basic short and long-term properties of generic repair materials are required under various exposure conditions. The principle requirements to ensure satisfactory long-term performance of the repair have always been high dimensional stability and relatively high early bond strength of the repair material with the substrate concrete. As part of a "Brite Euram" project, sponsored by E.E.C., the author has obtained considerable experimental data on properties of three commercially available generic repair materials, which are significant to the subsequent structural behaviour of repaired concrete members. A comparison is also made between the performance of these repair materials with a plain concrete mix of similar strength and stiffness. The following generic repair materials were used: a high performance non-shrinkable concrete, a mineral based cementitious material with no additives and no coarse aggregate size particles, and a cementitious mortar which contains styrene acrylic copolymer with fibre additives. The repair materials are supplied as single component systems by their manufacturers, ready for on-site mixing and use, and require only the addition of clean water. Data on strength, stiffness, post peak-load ductility under compression, swelling, shrinkage and creep deformations under various curing conditions are presented in this thesis. In addition water permeability coefficients and chloride penetration profiles of the materials at various ages of exposure have been determined. A comprehensive compilation of chloride diffusion data is made and an empirical expression is derived for the prediction of long-term chloride penetration profiles based on data obtained at relatively early ages. Application of this prediction model to the field data of some Arabian Gulf structures is made. The influence of repair materials on the performance of reinforced concrete compression members has been studied. A theoretical model is also derived to predict the long-term structural interaction between a repair patch and substrate concrete in short compression members of reinforced concrete. The model is based on the basic properties of materials, such as creep deformation, drying shrinkage and modulus of elasticity. The validity of the model is established on the basis of the experimental data obtained in this study. At the end of the thesis, conclusions and recommendations for future research are made.
37
Graszi, Nassib Nadim, and M. Zenkin. "Optimization of car operation and repair processes with use of remote electronic diagnostic systems." Thesis, Київський національний університет технологій та дизайну, 2019. https://er.knutd.edu.ua/handle/123456789/14598.
Full text
38
Jeon, J. "The development of a hybrid intelligent maintenance optimisation system." Thesis, University of Salford, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.313996.
Full text
39
Burger, A. F. (Adriaan Francois). "Scheduling algorithms for routine maintenance of roads in maintenance wards of a gravel road network." Thesis, Stellenbosch : Stellenbosch University, 2005. http://hdl.handle.net/10019.1/50446.
Full textAbstract:
Thesis (MScEng)--University of Stellenbosch, 2005.ENGLISH ABSTRACT: The study reported in this thesis focuses on the development of algorithms that can be used to schedule routine maintenance work in maintenance wards of a gravel road network, This was undertaken as part of the development of the Blading Optimisation Module of the Gravel Management System of the Provincial Government: Western Cape. Two scheduling algorithms were developed and mapped to a pilot object model on the computer. The algorithms and application interface takes account of the constraints and variables of routine maintenance that were identified through interviews with personnel of the five District Municipalities contained in the Western Cape. The algorithms are tested and evaluated using the pilot application. Based on the evaluation of the algorithms conclusions are drawn and recommendations are made.
AFRIKAANSE OPSOMMING: Die studie beskryf in hierdie tesis fokus op die ontwikkeling van algoritmes vir die skedulering van roetine instandhoudingswerk in instandhoudingswyke van 'n gruispadnetwerk. Dit is ondemeem tydens die ontwikkeling van die "Blading Optimisation Module" van die "Gravel Management System" van die Provinsiale Regering: Wes Kaap. Twee algoritmes is ontwikkel en afgebeeld op 'n loods-objekmodel op die rekenaar. Die algoritmes en toepassingskoppelvlak maak voorsiening vir die beperkings en veranderlikes wat geidentifiseer is tydens onderhoude met personeel van die distrikmunisipaliteite in die Wes Kaap. Die algoritmes is getoets en geevalueer met behulp van die loodstoepassing. Gevolgtrekkings en aanbevelings word gemaak op grond van die resultate van die evaluasie van die algoritmes.
40
Mahmood, Asif. "Maintenance and repair of gastrointestinal mucosa using recombinant peptides and natural products." Thesis, Imperial College London, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.443960.
Full text
41
Zenkin, M., and Y. Golovanova. "Ensuring the reliability of technical diagnostics of vehicles during maintenance and repair." Thesis, Київський національний університет технологій та дизайну, 2019. https://er.knutd.edu.ua/handle/123456789/14640.
Full text
42
Karim, Hawzheen. "Improved Road Design for Future Maintenance - Analysis of Road Barrier Repair Costs." Licentiate thesis, Stockholm : Division of Highway Engineering, Royal Institute of Technology, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-9260.
Full text
43
Supawiwat, Nutthapon. "A study on road slope management system considering maintenance and repair strategy." 京都大学 (Kyoto University), 2005. http://hdl.handle.net/2433/144540.
Full textAbstract:
Kyoto University (京都大学)0048
新制・課程博士
博士(工学)
甲第11867号
工博第2560号
新制||工||1358(附属図書館)
23647
UT51-2005-N701
京都大学大学院工学研究科土木システム工学専攻
(主査)教授 大西 有三, 教授 大津 宏康, 教授 中北 英一
学位規則第4条第1項該当
44
Rasmekomen, Nipat. "Condition-based maintenance for multi-component systems with degradation interactions." Thesis, University of Cambridge, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.709026.
Full text
45
Soldon, Brian T. "The International Space Station comparative maintenance analysis model (CMAM)." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Sep%5FSoldon.pdf.
Full text
46
Dao, Cuong D., and M. J. Zuo. "Selective maintenance for multi-state systems considering the benefits of repairing multiple components simultaneously." Springer, 2014. http://hdl.handle.net/10454/17980.
Full textAbstract:
NoMany industrial systems such as aircrafts, ships, manufacturing systems, etc. are required to perform several missions with finite breaks between missions. Maintenance is only available within the breaks. Due to the limitation of resources, all components in the system may not be maintained as desired. The selective maintenance problem helps the decision makers figure out what critical components to select and how to perform maintenance on these components. This paper studies the selective maintenance for multi-state series-parallel systems with the benefit of repairing multiple components simultaneously. Both time and cost savings can be acquired when several components are simultaneously repaired in a selective maintenance strategy. As the number of repaired components increases, the saved time and cost will also increase due to the share of setting up between components and another additional reduction amount from the repair of multiple identical components. A non-linear optimization model is developed to find the most reliable system subjected to time and cost constraints. Genetic algorithm is used to solve the optimization model. An illustrative example will be provided.
Natural Sciences and Engineering Research Council of Canada (NSERC) and Vietnam International Education Development (VIED)
47
Pound, Graeme Edward. "Ecological models of the maintenance of sexual reproduction." Thesis, University of Southampton, 2001. https://eprints.soton.ac.uk/45919/.
Full textAbstract:
A generic model of the interaction between sexual and asexual morphs in an ecological context was developed from the lotka-Volterra model of the population dynamics of two competing species (Doncaster, Pound & Cox, 2000). This revealed the threshold difference between the resource niches of sexual and asexual populations that allows coexistence between the two morphs. Coexistence depended on the respective carrying capacities of the sexual and asexual competitors, which we showed to be contingent upon the intrinsic growth capacity of the sexual population. The analytical model was extended to study (a) competition between a sexual population and numerous asexual clones; (b) competition between two metapopulation. A special formulation of Slatkin’s (1974) three-dimensional model of two competing metapopulations was developed with Lotka-Volterra dynamics, which yielded novel predictions for the behaviour of local and regional communities of species. Coexistence between sexual and asexual morphs maybe unsustainable due to the accumulation of clonal diversity over time, and indeed coexistence is rarely observed in nature. To study the dynamics of this accumulation, a stochastic model was developed for competition between asexual clones and a genetically diverse sexual population that exploits a range of resource niches. A model of the accumulation of deleterious mutations over time was incorporated into this framework. Monte-Carlo simulations demonstrated that a sexual population may, over time, exclude asexual clones whose fitness deteriorates due to the accumulation of deleterious mutations. These results suggest that whilst coexistence between sexual and asexual morphs is possible over ecological timescales the long-term outcome of an asexual invasion is determined by: 1) The relationship between genetic variation and niche breadth in the sexual population. 2) The rate as which the relative fitness of the asexual population declines with mutation accumulation. Reciprocal scenarios of the invasion of an asexual population by sexual mutants and sexual colonists are also considered.
48
Lai, Tsan-kei, and 黎贊基. "Condition auditing and repair of marine concrete structures in Hong Kong." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2001. http://hub.hku.hk/bib/B43894550.
Full text
49
Atterberg, Sheryl Wilkinson. "Factors related to consumer's perception of household appliance repair costs." Thesis, Kansas State University, 1986. http://hdl.handle.net/2097/9898.
Full text
50
Rehmert, Ian Jon. "Availability Analysis for the Quasi-Renewal Process." Diss., Virginia Tech, 2000. http://hdl.handle.net/10919/29270.
Full textAbstract:
The behavior of repairable equipment is often modeled under assumptions such as perfect repair, minimal repair, or negligible repair. However the majority of equipment behavior does not fall into any of these categories. Rather, repair actions do take time and the condition of equipment following repair is not strictly "as good as new" or "as bad as it was" prior to repair. Non-homogeneous processes that reflect this type of behavior are not studied nearly as much as the minimal repair case, but they far more realistic in many situations. For this reason, the quasi-renewal process provides an appealing alternative to many existing models for describing a non-homogeneous process. A quasi-renewal process is characterized by a parameter that indicates process deterioration or improvement by falling in the interval [0,1) or (1,Infinity) respectively. This parameter is the amount by which subsequent operation or repair intervals are scaled in terms of the immediately previous operation or repair interval. Two equivalent expressions for the point availability of a system with operation intervals and repair intervals that deteriorate according to a quasi-renewal process are constructed. In addition to general expressions for the point availability, several theoretical distributions on the operation and repair intervals are considered and specific forms of the quasi-renewal and point availability functions are developed. The two point availability expressions are used to provide upper and lower bounds on the approximated point availability. Numerical results and general behavior of the point availability and quasi-renewal functions are examined. The framework provided here allows for the description and prediction of the time-dependent behavior of a non-homogeneous process without the assumption of limiting behavior, a specific cost structure, or minimal repair.Ph. D.