Dissertations / Theses: 'Times to repair'

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Pitaš, Martin. "Analýza ztráty zisku dopravní organizace v důsledku opravy po nehodě u autobusů s obsaditelností nad 30 míst." Master's thesis, Vysoké učení technické v Brně. Ústav soudního inženýrství, 2011. http://www.nusl.cz/ntk/nusl-232565.

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The main aim of this master's thesis is preparation of economic and technical data for analysis of profit loss for a transport organization as a result of repair work after an accident involving buses with a carrying capacity of over 30 passengers. Master's thesis has three main parts. First part deals with technical data of buses SOR C 9,5, SOR C 10,5 a MAN Lion's Regio C, theirs equipment and service operation. Economic data about these buses are processed and evaluated in second part. Last part is devoted to the creation of methodology for calculation of profit loss of buses after an accident. It concerns about each model and category of buses with a carrying capacity of over 30 passengers as a whole.

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Hyatt, Marian M. "Adaptive reuse architecture : reconciling building and time." Thesis, Georgia Institute of Technology, 1995. http://hdl.handle.net/1853/23112.

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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.

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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.

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Söderholm, Matilda, and Lisa Habbe. "Estimating Time to Repair Failures in a Distributed System." Thesis, Linköpings universitet, Institutionen för datavetenskap, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-131847.

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To ensure the quality of important services, high availability is critical. One aspect to be considered in availability is the downtime of the system, which can be measured in time to recover from failures. In this report we investigate current research on the subject of repair time and the possibility to estimate this metric based on relevant parameters such as hardware, the type of fault and so on. We thoroughly analyze a set of data containing 43 000 failure traces from Los Alamos National Laboratory on 22 different cluster organized systems. To enable the analysis we create and use a program which parses the raw data, sorts and categorizes it based on certain criteria and formats the output to enable visualization. We analyze this data set in consideration of type of fault, memory size, processor quantity and at what time repairs were started and completed. We visualize our findings of number of failures and average times of repair dependent on the different parameters. For different faults and time of day we also display the empirical cumulative distributionfunction to give an overview of the probability for different times of repair. The failures are caused by a variety of different faults, where hardware and software are most frequently occurring. These two along with network faults have the highest average downtime. Time of failure proves important since both day of week and hour of day shows patterns that can be explained by for example work schedules. The hardware characteristics of nodes seem to affect the repair time as well, how this correlation works is although difficult to conclude. Based on the data extracted we suggest two simple methods of formulating a mathematical model estimating downtime which both prove insufficient; more research on the subject and on how the parameters affect each other is required.

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Cruz, David F. "Repair cycle time reduction at Naval Aviation Depots via reduced Logistics Delay Time." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1997. http://handle.dtic.mil/100.2/ADA342536.

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Thesis (M.S. in Management) Naval Postgraduate School, December 1997.
"December 1997." Thesis advisor(s): Keebom Kang, Donald Eaton. Includes bibliographical references (p. 87). Also available online.

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Santos, Leonardo Pereira. "Cost-effective dynamic repair for FPGAs in real-time systems." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2016. http://hdl.handle.net/10183/138206.

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Field-Programmable Gate Arrays (FPGAs) são largamente utilizadas em sistemas digitais por características como flexibilidade, baixo custo e alta densidade. Estas características advém do uso de células de SRAM na memória de configuração, o que torna estes dispositivos suscetíveis a erros induzidos por radiação, tais como SEUs. TMR é o método de mitigação mais utilizado, no entanto, possui um elevado custo tanto em área como em energia, restringindo seu uso em aplicações de baixo custo e/ou baixo consumo. Como alternativa a TMR, propõe-se utilizar DMR associado a um mecanismo de reparo da memória de configuração da FPGA chamado scrubbing. O reparo de FPGAs em sistemas em tempo real apresenta desafios específicos. Além da garantia da computação correta dos dados, esta computação deve se dar completamente dentro do tempo disponível (time-slot), devendo ser finalizada antes do tempo limite (deadline). A diferença entre o tempo de computação dos dados e a deadline é chamado de slack e é o tempo disponível para reparo do sistema. Este trabalho faz uso de scrubbing deslocado dinâmico, que busca maximizar a probabilidade de reparo da memória de configuração de FPGAs dentro do slack disponível, baseado em um diagnóstico do erro. O scrubbing deslocado já foi utilizado com técnicas de diagnóstico de grão fino (NAZAR, 2015). Este trabalho propõe o uso de técnicas de diagnóstico de grão grosso para o scrubbing deslocado, evitando as penalidades de desempenho e custos em área associados a técnicas de grão fino. Circuitos do conjunto MCNC foram protegidos com as técnicas propostas e submetidos a seções de injeção de erros (NAZAR; CARRO, 2012a). Os dados obtidos foram analisados e foram calculadas as melhores posição iniciais do scrubbing para cada um dos circuitos. Calculou-se a taxa de Failure-in-Time (FIT) para comparação entre as diferentes técnicas de diagnóstico propostas. Os resultados obtidos confirmaram a hipótese inicial deste trabalho que a redução do número de bits sensíveis e uma baixa degradação do período do ciclo de relógio permitiram reduzir a taxa de FIT quando comparadas com técnicas de grão fino. Por fim, uma comparação entre as três técnicas propostas é feita, analisando o desempenho e custos em área associados a cada uma.
Field-Programmable Gate Arrays (FPGAs) are widely used in digital systems due to characteristics such as flexibility, low cost and high density. These characteristics are due to the use of SRAM memory cells in the configuration memory, which make these devices susceptible to radiation-induced errors, such as SEUs. TMR is the most used mitigation technique, but it has an elevated cost both in area as well as in energy, restricting its use in low cost/low energy applications. As an alternative to TMR, we propose the use of DMR associated with a repair mechanism of the FPGA configuration memory called scrubbing. The repair of FPGA in real-time systems present a specific set of challenges. Besides guaranteeing the correct computation of data, this computation must be completely carried out within the available time (time-slot), being finalized before a time limit (deadline). The difference between the computation time and the deadline is called the slack and is the time available to repair the system. This work uses a dynamic shifted scrubbing that aims to maximize the repair probability of the configuration memory of the FPGA within the available slack based on error diagnostic. The shifted scrubbing was already proposed with fine-grained diagnostic techniques (NAZAR, 2015). This work proposes the use of coarse-grained diagnostic technique as a way to avoid the performance penalties and area costs associated to fine-grained techniques. Circuits of the MCNC suite were protected by the proposed techniques and subject to error-injection campaigns (NAZAR; CARRO, 2012a). The obtained data was analyzed and the best scrubbing starting positions for each circuit were calculated. The Failure-in-Time (FIT) rates were calculated to compare the different proposed diagnostic techniques. The obtained results validated the initial hypothesis of this work that the reduction of the number of sensitive bits and a low degradation of the clock cycle allowed a reduced FIT rate when compared with fine-grained diagnostic techniques. Finally, a comparison is made between the proposed techniques, considering performance and area costs associated to each one.

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Yoo, Dong Y. "Repair time model for different building sizes considering the earthquake hazard." Thesis, California State University, Long Beach, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10142981.

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Recent earthquakes devastated lives and destroyed a great stock of buildings. As a result, the earthquake-impacted regions incurred huge business and operation interruption losses. To minimize the business interruption losses through Performance-Based Seismic Design, there is an obvious need for a validated downtime model that would cover a large spectrum of building sizes and types. Building downtime consists of securing finances, mobilizing contractors, engineers and supplies, and the time to perform the actual repair, i.e., repair time. This study focuses on developing a model to characterize the repair time contribution to the downtime as an extension to FEMA P-58 Loss Assessment Methodology. The proposed repair time model utilizes the Critical Path Method for repair scheduling and realistic labor allocations that are based on the amount and severity of building damage. The model is validated on a significant sample of data collected through case studies from previous earthquakes, interviews with contractors, engineers, and inspectors. The proposed model also has a capability of scheduling resources to meet resource limitations that can either come from labor congestions or from a surge in demands following a disaster. The proposed resource scheduling method provides an efficient way of reducing the number of workers during labor congestions while minimizing its effect on the project duration. The final outcome is a realistic estimation of repair time associated with an earthquake.

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Nazar, Gabriel Luca. "Fine-grained error detection techniques for fast repair of FPGAs." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2013. http://hdl.handle.net/10183/77746.

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Field Programmable Gate Arrays (FPGAs) são componentes reconfiguráveis de hardware que encontraram grande sucesso comercial ao longo dos últimos anos em uma grande variedade de nichos de aplicação. Alta vazão de processamento, flexibilidade e tempo de projeto reduzido estão entre os principais atrativos desses dispositivos, e são essenciais para o seu sucesso comercial. Essas propriedades também são valiosas para sistemas críticos, que frequentemente enfrentam restrições severas de desempenho. Além disso, a possibilidade de reprogramação após implantação é relevante, uma vez que permite a adição de novas funcionalidades ou a correção de erros de projeto, estendendo a vida útil do sistema. Tais dispositivos, entretanto, dependem de grandes memórias para armazenar o bitstream de configuração, responsável por definir a função presente do FPGA. Assim, falhas afetando esta configuração são capazes de causar defeitos funcionais, sendo uma grande ameaça à confiabilidade. A forma mais tradicional de remover tais erros, isto é, scrubbing de configuração, consiste em periodicamente sobrescrever a memória com o seu conteúdo desejado. Entretanto, devido ao seu tamanho significativo e à banda de acesso limitada, scrubbing sofre de um longo tempo médio de reparo, e que está aumentando à medida que FPGAs ficam maiores e mais complexos a cada geração. Partições reconfiguráveis são úteis para reduzir este tempo, já que permitem a execução de um procedimento local de reparo na partição afetada. Para este propósito, mecanismos rápidos de detecção de erros são necessários para rapidamente disparar este scrubbing localizado e reduzir a latência de erro. Além disso, diagnóstico preciso é necessário para identificar a localização do erro dentro do espaço de endereçamento da configuração. Técnicas de redundância de grão fino têm o potencial de prover ambos, mas normalmente introduzem custos significativos devido à necessidade de numerosos verificadores de redundância. Neste trabalho, propomos uma técnica de detecção de erros de grão fino que utiliza recursos abundantes e subutilizados encontrados em FPGAs do estado da arte, especificamente as cadeias de propagação de vai-um. Assim, a técnica provê os principais benefícios da redundância de grão fino enquanto minimiza sua principal desvantagem. Reduções bastante significativas na latência de erro são atingíveis com a técnica proposta. Também é proposto um mecanismo heurístico para explorar o diagnóstico provido por técnicas desta natureza. Este mecanismo tem por objetivo identificar as localizações mais prováveis do erro na memória de configuração, baseado no diagnóstico de grão fino, e fazer uso dessa informação de forma a minimizar o tempo de reparo.
Field Programmable Gate Arrays (FPGAs) are reconfigurable hardware components that have found great commercial success over the past years in a wide variety of application niches. High processing throughput, flexibility and reduced design time are among the main assets of such devices, and are essential to their commercial success. These features are also valuable for critical systems that often face stringent performance constraints. Furthermore, the possibility to perform post-deployment reprogramming is relevant, as it allows adding new functionalities or correcting design mistakes, extending the system lifetime. Such devices, however, rely on large memories to store the configuration bitstream, responsible for defining the current FPGA function. Thus, faults affecting this configuration are able to cause functional failures, posing a major dependability threat. The most traditional means to remove such errors, i.e., configuration scrubbing, consists in periodically overwriting the memory with its desired contents. However, due to its significant size and limited access bandwidth, scrubbing suffers from a long mean time to repair, and which is increasing as FPGAs get larger and more complex after each generation. Reconfigurable partitions are useful to reduce this time, as they allow performing a local repair procedure on the affected partition. For that purpose, fast error detection mechanisms are required, in order to quickly trigger this localized scrubbing and reduce error latency. Moreover, precise diagnosis is necessary to identify the error location within the configuration addressing space. Fine-grained redundancy techniques have the potential to provide both, but usually introduce significant costs due to the need of numerous redundancy checkers. In this work we propose a fine-grained error detection technique that makes use of abundant and underused resources found in state-of-the-art FPGAs, namely the carry propagation chains. Thereby, the technique provides the main benefits of fine-grained redundancy while minimizing its main drawback. Very significant reductions in error latency are attainable with the proposed approach. A heuristic mechanism to explore the diagnosis provided by techniques of this nature is also proposed. This mechanism aims at identifying the most likely error locations in the configuration memory, based on the fine-grained diagnosis, and to make use of this information in order to minimize the repair time of scrubbing.

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Mendes, de Oliveira Martins Carlos Daniel. "Real-time studies of DNA repair kinetics following low-LET short-pulse electron radiation." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:63a874a6-9348-4504-b4cd-b1cfd129b75d.

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Radiation-induced damage to the genomic DNA of cells may lead to errors in transcription and replication and, if not repaired correctly, these may result in mutations, genomic instability and cell death. Laser microbeams have generally been used by many research groups to investigate the real-time dynamics of protein recruitment in response to DNA insults in mammalian cells; however, such irradiations induce a plethora of DNA damage (including UV base damage, base damage, SSBs and DSBs and complex damage). A novel experimental setup has been designed capable of following the dynamics of protein recruitment in response to DNA insults in mammalian cells shortly following submicrosecond- pulsed electron irradiation of living mammalian cells, not possible using conventional irradiation techniques. This arrangement was developed based on a 6 MeV electron pulse linear accelerator, to deliver sparsely ionising radiation, coupled to an automated, time-lapse inverted epifluorescence microscope imaging system. An integrated robotic system contained within a physiological environment of 37°C and 5% CO₂ was used to transfer remotely and repetitively custom-designed cell dishes containing the mammalian cells between irradiation and imaging locations. Following the development of the linear accelerator and associated imaging devices, preliminary ‘proof-of-principle’ investigations were carried out using living HT1080 mammalian cells containing YFP-tagged 53BP1, an established biomarker of DSB, to follow the recruitment and loss of 53BP1 to sites of radiation-induced DNA damage in real-time. This novel experimental setup has allowed for the first time observations of the appearance and disappearance of radiation-induced foci in the same cell population at very early times. These single-foci studies have provided evidence for the formation of not only promptly formed DSBs but also late appearing DNA damage signalled by 53BP1. These data highlight different classes of DSBs formed in response radiation damage. Additionally, the role of cell cycle on the repair kinetics was undertaken using HT1080- 53BP1-YFP cells which also express Geminin-mCherry under appropriate selection. Geminin is increasingly expressed from early S-phase onwards, but is degraded following mitosis. Geminin-associated fluorescence can be used as a marker of progression through the cell cycle. 53BP1 repair kinetics were characterised in response to radiation damage in combination with ATM and PARP inhibitors. These studies provided supporting evidence for the existence of different classes of DSBs, potentially assigned to radiation-induced replication breaks and DSBs formed by enzymatic conversion of clustered damage. These preliminary ‘proof-of-principle’ findings using DNA damage repair as an example, emphasize the use of this novel technology to explore the dynamics of numerous other biochemical processes in living cells in real-time with the knowledge of being able to quantify the range of damage induced by IR coupled with accurate dosimetry. The knowledge obtained may be used to identify potential biological targets coupled with drug discovery for translation into adjuncts for radiotherapy.

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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.

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No
Many 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)

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LEMAI, Solange. "IXTET-EXEC: planning, plan repair and execution control with time and resource management." Phd thesis, Institut National Polytechnique de Toulouse - INPT, 2004. http://tel.archives-ouvertes.fr/tel-00009496.

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Augmenter l'autonomie décisionnelle des systèmes spatiaux (satellites, sondes et rovers) soulève de nouveaux problèmes tels que la planification des activités pour accomplir un but, le contrôle de l'exécution du plan, et la surveillance et le diagnostic du système. Nous nous intéressons plus particulièrement à la planification d'une mission et au contrôle de son exécution dans le cadre d'une application avec des contraintes temporelles (rendez-vous avec des fenêtres de visibilité&) et la gestion de ressources limitées (énergie, carburant&). Cette thèse propose un cadre général pour intégrer la planification, l'exécution et l'adaptation réactive d'un plan en exploitant la flexibilité temporelle et le parallélisme des plans produits par un planificateur non linéaire causal basé sur des techniques de satisfaction de contraintes (notamment la représentation des contraintes temporelles est faite sous la forme d'un Simple Temporal Network). Cette approche a été mise en Suvre dans le système IxTeT-eXeC qui se compose d'un exécutif temporel et du planificateur IxTeT, modifié pour améliorer la flexibilité de la représentation des ressources et prendre en compte le contexte d'exécution et la durée de la recherche lors de la planification. L'exécutif contrôle les deux mécanismes d'adaptation du plan (en cas d'échecs ou de nouveaux buts) : (1) une réparation en parallèle de l'exécution de ses parties valides, (2) une replanification complète. IxTeT-eXeC a été intégré dans le niveau décisionnel de l'architecture LAAS, en interaction avec l'exécutif procédural OpenPRS, pour contrôler un robot mobile autonome avec une mission d'exploration.

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Grunzke, Shawn D. "Statistical analysis of naval aviation depot repair cycle time reduction for the F /." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2001. http://handle.dtic.mil/100.2/ADA392071.

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Lemai-Chenevier, Solange. "Ixtet-exec : planning, plan repair and execution control with time and resource management." Toulouse, INPT, 2004. http://www.theses.fr/2004INPT017H.

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Dans le but d'augmenter l'autonomie décisionnelle de systèmes spatiaux (e. G. Rovers), nous proposons un cadre pour intégrer la planification,l'exécution et l'adaptation réactive d'un plan, en exploitant la flexibilité des plans produits par un planificateur non linéaire basé sur des CSPs. Ce type d'application impose de respecter des contraintes temporelles et de gérer des ressources limitées. Le système IxTeT-eXeC se compose d'un exécutif temporel et du planificateur IxTeT, modifié pour améliorer la flexibilité de la représentation des ressources et prendre en compte le contexte d'exécution et la durée de la recherche lors de la planification. L'exécutif contrôle les deux mécanismes d'adaptation du plan (en cas d'échecs ou de nouveaux buts): (1) une réparation en parallèle de l'exécution de ses parties valides, (2) une replanification complète. IxTeT-eXeC a été intégré dans l'architecture LAAS pour contrôler un robot mobile avec une mission d'exploration.

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Leipnitz, Marcos Tomazzoli. "Resilient regular expression matching on FPGAs with fast error repair." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2017. http://hdl.handle.net/10183/168788.

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O paradigma Network Function Virtualization (NFV) promete tornar as redes de computadores mais escaláveis e flexíveis, através do desacoplamento das funções de rede de hardware dedicado e fornecedor específico. No entanto, funções de rede computacionalmente intensivas podem ser difíceis de virtualizar sem degradação de desempenho. Neste contexto, Field-Programmable Gate Arrays (FPGAs) têm se mostrado uma boa opção para aceleração por hardware de funções de rede virtuais que requerem alta vazão, sem se desviar do conceito de uma infraestrutura NFV que visa alta flexibilidade. A avaliação de expressões regulares é um mecanismo importante e computacionalmente intensivo, usado para realizar Deep Packet Inpection, que pode ser acelerado por FPGA para atender aos requisitos de desempenho. Esta solução, no entanto, apresenta novos desafios em relação aos requisitos de confiabilidade. Particularmente para FPGAs baseados em SRAM, soft errors na memória de configuração são uma ameaça de confiabilidade significativa. Neste trabalho, apresentamos um mecanismo de tolerância a falhas abrangente para lidar com falhas de configuração na funcionalidade de módulos de avaliação de expressões regulares baseados em FPGA. Além disso, é introduzido um mecanismo de correção de erros que considera o posicionamento desses módulos no FPGA para reduzir o tempo de reparo do sistema, melhorando a confiabilidade e a disponibilidade. Os resultados experimentais mostram que a taxa de falha geral e o tempo de reparo do sistema podem ser reduzidos em 95% e 90%, respectivamente, com custos de área e performance admissíveis.
The Network Function Virtualization (NFV) paradigm promises to make computer networks more scalable and flexible by decoupling the network functions (NFs) from dedicated and vendor-specific hardware. However, network and compute intensive NFs may be difficult to virtualize without performance degradation. In this context, Field-Programmable Gate Arrays (FPGAs) have been shown to be a good option for hardware acceleration of virtual NFs that require high throughput, without deviating from the concept of an NFV infrastructure which aims at high flexibility. Regular expression matching is an important and compute intensive mechanism used to perform Deep Packet Inspection, which can be FPGA-accelerated to meet performance constraints. This solution, however, introduces new challenges regarding dependability requirements. Particularly for SRAM-based FPGAs, soft errors on the configuration memory are a significant dependability threat. In this work we present a comprehensive fault tolerance mechanism to deal with configuration faults on the functionality of FPGA-based regular expression matching engines. Moreover, a placement-aware scrubbing mechanism is introduced to reduce the system repair time, improving the system reliability and availability. Experimental results show that the overall failure rate and the system mean time to repair can be reduced in 95% and 90%, respectively, with manageable area and performance costs.

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Ropiak, Michael J. "Statistical analysis of the Naval inventory control point repair turn-around time forecase model." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2000. http://handle.dtic.mil/100.2/ADA381208.

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Scott, Thomas A., and Troy D. Landry. "An assessment of the Marine Corps integrated logistics capability initiative - repair cycle time reduction." Thesis, Monterey, California. Naval Postgraduate School, 2002. http://hdl.handle.net/10945/5885.

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Approved for public release; distribution is unlimited.
In this thesis, we examine the Marine Corps Integrated Logistics Capability (ILC) initiatives to reduce Repair Cycle Time (RCT) for ground equipment from 53 days to 34 days by fiscal year 2006 (a 35 percent reduction). Based on Little's Law, the Marine Corps could save a substantial amount of money on inventory and improve operational availability of its weapon systems by reducing RCT. We used ARENA simulation software to construct a baseline model of the current maintenance process. We then made modifications to the baseline model to test the Marine Corps' prediction that the proposed ILC initiatives of maintenance consolidation will result in a 35 percent RCT reduction. Our final simulation model focused on future changes that will reduce RCT by 50 percent. We find that based upon the consolidation of maintenance echelons that the Marine Corps is only able to reduce RCT by 32.5 percent. We find that a 10 percent reduction in retail Order Ship Time (OST) and other maintenance processes will allow the Marine Corps to meet the RCT goal of 35 percent reduction. We find that the reduction of additional maintenance processes coupled with variance reduction of retail OST can reduce RCT by 50 percent.

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Landry, Troy D. Scott Thomas A. "An assessment of the Marine Corps integrated logistics capability initiative repair cycle time reduction /." Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2002. http://library.nps.navy.mil/uhtbin/hyperion-image/02Jun%5FLandry%5FScott.pdf.

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Jat, Mohsin Nasir. "Time-differentiated distribution of service parts and repair materials : an investigation of service time, area partitions, and cost relations." Thesis, University of Nottingham, 2015. http://eprints.nottingham.ac.uk/28408/.

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Motivation: Manufacturers in sectors like Information Technology (IT), Automotive and Aerospace have increasingly become focused on providing after sales services. One of the forms of after sales services is to provide service parts (or spare parts) to customers within different contracted time windows. Commonly offered by large scale IT sector companies, such services are facilitated by Service Parts Logistics (SPL) systems through a network of parts stocking facilities. The number of stocking facilities in a distribution network affects the service responsiveness and service costs related to inventory, transportation and facility set-up. Higher responsiveness can be attained through increasing the number of facilities in a distribution network, which, in turn, usually increases inventory cost. Generally, studies assume that shorter service time windows result in higher costs, but there is a lack of exploration regarding how reductions in service time limits and changes in the fractions of demand for different time-based service types impact on various service related costs. Service area partitioning (or zoning) is another related issue which is unexplored in general facility location literature when considering multiple service time (or distance) constraints and both inventory and transportation costs. This study is mainly motivated by SPL systems of IT equipment manufacturers that support the provision of service parts at customer sites under different and short service time commitments in a large geographical area. The study is of a generic nature and generates insights that can be relevant for any case where the service responses are provided within different short time windows and involve the provision (or consumption) of some stocks (e.g. emergency infrastructure repairs). Aim and methodology: The aim of this work is to investigate relationships between time-based service levels, service costs and service zones/areas under a hierarchical organization and a non-hierarchical organization of service facilities. The hierarchical organization has variable capabilities to meet different time-based requirements, while the non-hierarchical organization has a uniform capability to meet the toughest requirement for the entire customer base. The investigation is mainly done through analytical, simulation and optimization modelling with the view of producing answers that provide a general understanding and practical insights rather than producing situation specific optimization models. Empirical case studies are also conducted to complement the quantitative modelling work so that the research is not divorced from the reality. The case studies point towards the motivation for the modelling study and its relevance to some of the real-world systems, and provide a broader understanding of the issues being researched. The case studies involve two multinational ICT equipment manufacturers and service provides, and a government agency responsible for providing highway emergency services in England. Key findings: The results from the modelling experiments show that under the non-hierarchical setup, where all facilities provide the full range of service-times in their respective vicinities, inventory and transportation costs are insensitive to the fractions of demand for different time-based service types. However, with an inventory sharing mechanism under the non-hierarchical setup, the increase in the proportion of demand for the service within the longer time window can increase the service availability level while also increasing the average travelling. On the other hand, under the hierarchical setup, which provides a higher level of centralization when there is demand for the service in the longer time window, inventory and transportation costs react to the proportions of demand for different time-based service types. The hierarchical setup results in higher transportation cost compared to the non-hierarchical setup, and, interestingly, does not necessarily lower the inventory level, especially when the overall demand rate is very low. The simulation of the inventory sharing mechanism under the hierarchical setup shows that, in several cases, inventory sharing can not only increase the service availability level, but can also reduce transportation cost. The analysis based on the optimization models shows that there can be cases where it is more cost effective to serve all demand, regardless of the required service time, in a similar fashion through a non-hierarchical setup. The results also show that the demand fractions for different time-based service types, and inventory and transportation costs can significantly impact on the optimum organization of service zone. There can be distinct optimum patterns of service zones depending on whether the inventory cost or the transportation cost dominates.

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Kao, Ya-Ting. "Ultrafast Dynamics of Flavin Cofactor in DNA Repair by Photolyase and in Signaling Formation of Cryptochrome." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1272467278.

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Mooney, Kevin F. Sanchez Guy R. "Improved aviation readiness and inventory reductions through repair cycle time reductions using modeling and simulation /." Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1997. http://handle.dtic.mil/100.2/ADA345928.

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Thesis (M.S. in Systems Management) Naval Postgraduate School, December 1997.
Thesis advisor(s): Keebom Kang, Donald R. Eaton. "December 1997." Includes bibliographical references (p. 115). Also available online.

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Mooney, Kevin F., and Guy R. Sanchez. "Improved aviation readiness and inventory reductions through repair cycle time reductions using modeling and simulation." Thesis, Monterey, California. Naval Postgraduate School, 1997. http://hdl.handle.net/10945/31922.

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This thesis research focuses on improved aviation readiness and reductions in pipeline inventory investment through repair Turn Around Time reductions related to the component repair processes internal to the Naval Aviation Depot (NADEP). Specific emphasis was given to the repair flow of a specific component from induction into the Depot for repair to the ultimate availability for sale to customers in a ready-for-issue status. The research models the current NADEP repair process flow and simulates enhancements to the process flow. These enhancements identify savings of over $52,000 in repair pipeline inventory investment for the candidate item. Our model and associated simulations provide NADEP with graphical and quantitative feedback which demonstrates the impact of process flow enhancements on repair Turn Around Time and Work in Process inventory efficiency.

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Santos, William O. "An analysis of the prediction accuracy of the U.S. Navy repair turn-around time forecast model." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2003. http://library.nps.navy.mil/uhtbin/hyperion-image/03Jun%5FSantos.pdf.

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Thesis (M.S. in Operations Research)--Naval Postgraduate School, June 2003.
Thesis advisor(s): Robert A. Koyak, Samuel E. Buttrey. Includes bibliographical references (p. 55). Also available online.

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Hughes, Craig David. "Real time single molecule investigation of the dynamics of nucleotide excision repair proteins on DNA tightropes." Thesis, University of Essex, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.654484.

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Through the use of a biochemical technique that allows single strands of DNA to be visualized, the dynamics of nucleotide excision repair proteins was studied at the single molecule level. This DNA tightrope technique has allowed for the interaction of proteins with double stranded, single stranded, crowded and damaged DNA to be observed. Bacterial nucleotide excision repair proteins UvrC and UvrBC were loaded onto undamaged DNA to understand how UvrC locates the UvrB-DNA pre-incision complex. It was obseNed that UvrC facilitates UvrB binding to DNA in the absence of UvrA and as this UvrBC complex was abundant, indicates that UvrC is most likely present in an UvrBC complex in vivo. Mutant studies demonstrated that UvrBC binds to DNA through UvrB's DNA binding domain, signifying that the UvrBC complex forms in order to help UvrC locate an UvrB pre-incision DNA damage complex and to stop unchecked endonuclease activity. It was proposed that this UvrBC complex may also benefit UvrC in maneuvering around obstructions on the DNA. Within a cell DNA will always be involved in a multitude of differentreactions concurrently, therefore obseNations on how NER proteins behaved on crowded DNA was studied. These results demonstrated that both UvrBC and UvrC have difficulties overcoming protein obstructions. This suggests that the main mechanism of movement of UvrC and UvrBC on the DNA is a one dimensional search, with the possible capability of switching to a 3D search. The eukaryotic NER protein XPD was also imaged, demonstrating a single stranded DNA binding preference over that of double stranded DNA. The XPD protein was also obseNed to have an absolute requirement for A TP in order to have motion on the DNA. Once damage was introduced into the DNA it was obseNed that UvrB facilitates UvrC binding to damaged DNA, through the UvrB-DNA binding domain. This previously unreported damage detection mechanism of UvrBC originates from UvrB's ~-hairpin motif's interaction with DNA. It was therefore suggested that UvrBC's damage .detection is a redundancy system in the NER pathway.

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Yahaya, Badrul H. "Analysis of time-dependent transcriptomic and phenotypic changes associated with repair and regeneration in the airway epithelium." Thesis, University of Edinburgh, 2010. http://hdl.handle.net/1842/4800.

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The airway epithelium demonstates the ability to quickly repair following physical injury. The morphologic features of this dynamic repair process have been well characterised at the anatomic and cellular level using a number of animal model systems and these studies have provided a solid foundation upon which our understanding of normal repair is build. With the advent of molecular and bioinformatic tools and resources the opportunity exists to extend the value of these models in defining the molecular pathways and interactions that underlay the normal repair process. This thesis represents a realisation of this opportunity. A large animal model was developed in which selected areas of airway epithelium were subjected to bronchial brush biopsy as part of routine bronchoscopic examination prcedures in anaethetised sheep. The process resulted in a physical perturbation of the normal pseudostratified structure of the sheep airwway epithelium at specific locations. By careful experimental design it was possible, within the same animals. to identify and sample from sites undergoing repair at different intervals subsequent in injury. To supplement the histological evaluation of the repair process and align findings with extablished small animal models of airway epithelial repair proliferative cell labelling strategies were implemented in order to study the location and extent of cellular proliferation occurring duringthe repair process. Molecular approaches towards defining the transcriptional response to physical injury comprised application of microarray technology using a commercially sources array platform. Such approach demanted preliminary effort directed towards optimising RNA integrity and yield from airway samples. Following preliminary studies directed towards optimising the model conditions patterns of airway epithelial repair following bronchial brush biopsy were studies in eight sheep at degined time points (6 hours, 1,3, & 7 days) post-injury. Bronchial brush biopsy resulted in the acute removal of the epithelial cell layer and components of the underlying structures. repair processes were rapidly implemented through initial epithelial dedifferentiation, proliferatino and migration at the wound margins and subsequent time-depentend changes in the proportion of subepithelial structures, including smooth muscle and blood vessels, as the epithelial surface moved towards repair. Transcriptional analysis revewaled that over 13,000 probes showed evidence of differential expession at some point during the repair process (p<0.05), whilst of these, 1491 probes had in excess of a two-fold change in expression. array results were validated against conventional semi-quantitative RT-PCR for selected genes. Differentially expressed genes with previously characterised roles in epithelial migration, prolifereation and differentiation were identified during the repair process. The relative emphasis of gene products with particular functional roles varied during the course of repair. Indeed gene ontology (GO) terms identified included those associated with the inflammatory response, cellular migration, extracellular matrix activities, differentiation, proliferation, cellular development, cell cycle activities, cellular adhesion, apoptosis and mitosis. In addition the Kyoto Encyclopedia of Genes and Gneomes (KEGG) databases were queried and such process indicated the involvement of cell communication, 053 and complement and coagulation cascade pathways throughout the repair process, initial (6h) Toll-like receptor and cytokine-cytoine receptor interaction pathways, and the progressive involement of cell cycle, focal adhesion and extracellulaar matrix (ECM)-receptor, and cytokine interaction pathways as the epithelium repaired. The model of airway epithelial injury developed in this thesis generated features broadly consistent with those previosly described in relation to various small animal model systems. Importantly, and in addition, this thesis defines the molecular features associated with repair in this model system and provides a useful resource with which to assess the comparative fetures of the airway transcriptional response to physical injury, It is through such comparison, using analogous methodology, that the fundamental pathways and interactions that underlay normal repair and regeneration can be identified and therafter extended towards inderstanding the basis for variation associated with natural and experimental disease.

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Baker, Ross E. "The time course of changes in skeletal muscle metabolites during muscle repair, as detected by proton nuclear magnetic resonance spectroscopy." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0002/MQ41678.pdf.

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Madonsela, Alex Thulani. "A structured approach for the reduction of mean time to repair of blast furnace D, ArcelorMittal, South Africa, Vanderbijlpark / Madonsela A.T." Thesis, North-West University, 2011. http://hdl.handle.net/10394/7311.

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Organizations are expected by their shareholders to continually deliver above industry returns on capital invested and to remain competitive in the industry of choice through productivity, safety and quality. The maintenance function is a key area in which competitiveness through efficiencies and world–class performance can be attained by focusing on the prevention and reduction of long and costly equipment repair times. The question is: how can the mean time to repair of equipment already installed in the plant be reduced? To answer the above question correctly and comprehensively, the research explored mixed methods in finding answers. Quantitative methodology using a survey was used for data collection. Observations and interviews were held with maintenance personnel to uncover information that couldn’t have been obtained by means of a survey. The survey was limited to equipment performance measures, human factors, environmental factors, planning, spare parts, maintainability, procedures and training. To test consistency and accuracy of representation of the total population under study, a reliability test was done by using Cronbach’s alpha coefficient. To determine whether there are any differences between groups, an ANOVA test was used. Cohen’s d–value was used to determine practically significant differences between one set of data with another and correlation analysis was used to determine the relationships between the variables. The approach designed and delivered by this research flowed from the existing body of knowledge, case studies and survey findings. The approach adopts some of the elements of the failure mode and effects analysis (FMEA) procedure and differs from other work that has been done by others by taking into account the competency and experience of maintenance personnel and assigning to them factors which are used to compute anew MTTR of the equipment. The cost of implementing the recommended corrective actions for realising the new MTTR is determined and evaluated against an improved equipment availability that will be achieved as a result of the recommended corrective actions assuming that the failure rate of the equipment remains constant. This evaluation step imbedded within the approach is valuable for the maintenance function and management for decision making in ensuring that resources at the organization’s disposal are used productively. Validation and test results of the approach showed that the MTTR of equipment installed in the plant can be reduced. The results also indicated that through the use of the designed approach a regular pattern of repair or replacement times can be followed well in advance and that it is practical, user friendly and it also delivers on its objective of offering a structure for analysis and decision making aimed at reducing the MTTR. Included with this dissertation is feedback information that can be included in a maintenance job card feedback section to capture information about factors that can be improved to lower the MTTR as part of a continuous improvement process. Included also is a spare part development and management procedure that can be used by the maintenance function. Recommendations on training of maintenance personnel on the maintainability of equipment, the FMEA procedure and maintenance procedures are highlighted. Information that flowed from this approach will be valuable for continuous plant performance improvement and during the design, installation and operation stages of a blast furnace.
Thesis (M.Ing. (Development and Management Engineering))--North-West University, Potchefstroom Campus, 2012.

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Kazui, Toshinobu, Nicole Sydow, Mark Friedman, Samuel Kim, Scott Lick, and Zain Khalpey. "A modified Park's stitch to correct aortic insufficiency for bioprosthetic valve at time of left ventricular assist device implant: a case report." BIOMED CENTRAL LTD, 2016. http://hdl.handle.net/10150/622886.

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Background: Aortic valve insufficiency (AI) at the time of left ventricular assist device (LVAD) insertion needs to be corrected, however there is little known about how to manage bioprosthetic valvular AI. Case presentation: A 55-year-old female with dilated cardiomyopathy who previously had a bioprosthetic aortic valve replacement needed a LVAD as a bridge to transplant. Her left ventricular ejection fraction was 10% and had mild to moderate transvalvular AI. She underwent a HeartWare HVAD insertion along with aortic valvular coaptation stitch repair (Park's stitch) to the bioprosthetic valve. Conclusion: Her AI improved to trivial with minimal ejection through the bioprosthetic valve. She was transplanted 6 months following the surgery. A Park's stitch to the bioprosthetic aortic valve with more than mild AI might be a good option for bridge to transplant patient.

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Paredes, Nateros Javier Glenne, and Mendoza Jhon Rogger Tupez. "Incremento de la producción de cuadernos a partir de la implementación del RCM en la Gestión de Mantenimiento." Bachelor's thesis, Universidad Peruana de Ciencias Aplicadas (UPC), 2019. http://hdl.handle.net/10757/626431.

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Dentro del contenido de este documento se desarrolla una propuesta para incrementar la producción de cuadernos en la línea R17de la empresa Panasa, aplicando la metodología RCM. En el capítulo 1 se presenta una revisión bibliográfica de los temas principales sobre los que se fundamenta la propuesta de mejora: el sector papelero en el Perú, la evolución del mantenimiento, definición de términos, tipos de mantenimiento, técnicas de mantenimiento avanzado (RCM, TPM), costos de mantenimiento, indicadores, herramientas de mejora continua y casos de éxitos en la implementación del RCM. En el capítulo 2 se realiza una descripción general de la empresa (reseña histórica, misión, visión, valores, organigrama, productos, clientes, ventas y el proceso productivo) para finalmente llegar al detalle de la situación actual. Luego se describe y cuantifica el principal problema que afecta al cumplimiento del plan de producción anual, posteriormente se hace el análisis de causa raíz para identificar las principales causas que están generando el problema. En el capítulo 3 se evalúa tres posibles soluciones para el problema (RCM, TPM, CBM), para la elección de la metodología a aplicar se hace uso del ranking de factores y se desarrolla cada una de las fases del RCM. En el capítulo 4 se valida la propuesta para lo cual se hace un modelamiento del proceso actual y propuesto utilizando el Software de simulación ARENA, también se hace una evaluación económica-financiera para determinar la viabilidad del proyecto. El cierre de la tesis se da mediante la presentación de las conclusiones y recomendaciones.
This document develops a proposal to increase the production of notebooks in the R17 line of the Panasa company, applying the RCM methodology. Chapter 1 presents a bibliographic review of the main topics on which the proposal for improvement is based: the paper industry in Peru, the evolution of maintenance, definition of terms, types of maintenance, advanced maintenance techniques (RCM, TPM), maintenance costs, indicators, continuous improvement tools and success stories in the implementation of the RCM. In Chapter 2 a general description of the company (historical review, mission, vision, values, organization chart, products, customers, sales and the production process) is made to finally get to the detail of the current situation. Then the main problem that affects the fulfillment of the annual production plan is described and quantified, then the root cause analysis is done to identify the main causes that are generating the problem. Chapter 3 evaluates three possible solutions to the problem (RCM, TPM, CBM), for the choice of the methodology to be applied, the ranking of factors is used and each phase of the RCM is developed. Chapter 4 validates the proposal for which a modeling of the current and proposed process is done using the ARENA simulation software, an economic-financial evaluation is also made to determine the viability of the project. The thesis is closed by presenting the conclusions and recommendations.
Tesis

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Gigot, Sébastien. "Contribution à la conception d’une base de données de maintenabilité opérationnelle dynamique : Proposition de prise en compte des facteurs pénalisants dans l’estimation du MTTR [Mean Time To Repair]." Ecole nationale d'ingénieurs (Saint-Etienne), 2013. http://www.theses.fr/2013ENISE021.

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Cette thèse a pour but d’exposer une méthodologie d’évaluation du risque de ne pas satisfaireaux exigences de maintenabilité pour des équipements industriels complexes en exploitation. Elle permet de mieux comprendre la problématique du dépassement de la durée de réparation lié aux activités de maintenabilité opérationnelle. Peu d’études sont à l’heure actuelle, consacrées à ce sujet rendu complexe par la multitude d’activités différentes et un niveau d’exigence sans cesse croissant. Les exigences de maintenabilité et de disponibilité apparaissent de plus en plus. Notre proposition porte sur l’évaluation des critères de maintenabilité critiques intervenant dans un processus de maintenabilité afin d’optimiser l’enchaînement des actions depuis la panne jusqu’à la remise en service. L’analyse de ces facteurs pénalisants nous conduit à développer un modèle d’estimation du MTTR pour minimiser le delta des dérives liées au dépassement des délais de réparation. Les résultats illustrés d’exemples concrets permettent d’apprécier la maintenabilité du système au regard des objectifs fixés et de proposer le cas échéant, des actions en diminution de risques pour optimiser l’indisponibilité du système. Ce travail s’est intéressé au développement d'une démarche de modélisation des systèmes complexes pour l'évaluation des stratégies de maintenance. Son aboutissement est un outil d'aide à la décision pour construire et satisfaire aux programmes de maintenance en effectuant les choix les mieux adaptés. Nos travaux ont portés sur la maintenabilité opérationnelle et sur l’importance de l’estimation des durées de réparation en prenant en compte le contexte dans lequel évolue le système afin d’identifier les événements pénalisants. Ces travaux viennent souligner l’importance à accorder aux méthodologies de traitement d’une panne, en proposant de reconsidérer le concept de maintenabilité opérationnelle afin de mieux maîtriser les aléas liés au dépassement des durées de réparation
This thesis is intended to describe a methodology for assessment of the risk of not satisfying the requirements of maintainability for industrial equipment complex in operation. It allows you to better understand the problematic of the overrun of the duration of repair linked to the activities of operational serviceability. Few of the studies are at the present time, devoted to this topic made complex by the multitude of different activities and a level of requirement always growing. The requirements of maintainability and availability appear more and more. Our proposal focuses on the evaluation of the criteria of maintainability criticisms involved in a process of maintainability in order to optimize the sequence of actions since the fault up to the rehabilitation service. The analysis of these inhibiting factors led us to develop a model for estimating of the MTTR to minimize the delta of derivatives linked to the overrun of the repair time. The results illustrated by specific examples allow to assess the maintainability of the system in relation to the objectives set and to propose, if necessary, actions to decrease of risks to optimize the system unavailability. This work is interested in the development of an approach to the modeling of complex systems for the assessment of maintenance strategies. Its culmination is a tool to help in the decision to build and meet the maintenance programs by performing the choice best suited. Our works have focused on the operational maintainability and on the importance of the estimation of repair times taking into account the context in which evolved the system in order to identify the events penally. These works have stressed the importance to be given to the methodology of treatment of a failure, by proposing to reconsider the concept of maintainability operational in order to better control the uncertainties related to the excedance of repair times

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Wu, Xinhao, and Maike Zhang. "An empirical assessment of the predictive quality of internal product metrics to predict software maintainability in practice." Thesis, Blekinge Tekniska Högskola, Institutionen för programvaruteknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-20149.

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Background. Maintainability of software products continues to be an area of im- portance and interest both for practice and research. The time used for maintenance usually exceeds 70% of the whole period of software development process. At present, there is a large number of metrics that have been suggested to indicate the main- tainability of a software product. However, there is a gap in validation of proposed source code metrics and the external quality of software maintainability. Objectives. In this thesis, we aim to catalog the proposed metrics for software maintainability. From this catalog we will validate a subset of commonly proposed maintainability indicators. Methods. Through a literature review with a systematic search and selection ap- proach, we collated maintainability metrics from secondary studies on software main- tainability. A subset of commonly metrics identified in the literature review were validated in a retrospective study. The retrospective study used a large open source software "Elastic Search" as a case. We collected internal source code metrics and a proxy for maintainability of the system for 911 bug fixes in 14 version (11 experi- mental samples, 3 are verification samples) of the product. Results. Following a systematic search and selection process, we identified 11 sec- ondary studies on software maintainability. From these studies we identified 290 source code metrics that are claimed to be indicators of the maintainability of a soft- ware product. We used mean time to repair (MTTR) as a proxy for maintainability of a product. Our analysis reveals that for the "elasticsearch" software, the values of the four indicators LOC, CC, WMC and RFC have the strongest correlation with MTTR. Conclusions. In this thesis, we validated a subset of commonly proposed source code metrics for predicting maintainability. The empirical validation using a popu- lar large-scale open source system reveals that some metrics have shown a stronger correlation with a proxy for maintainability in use. This study provides important empirical evidence towards a better understanding of source code attributes and maintainability in practice. However, a single case and a retrospective study are insufficient to establish a cause effect relation. Therefore, further replications of our study design with more diverse cases can increase the confidence in the predictive ability and thus the usefulness of the proposed metrics.

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Reed, Andrew J. "A Structural and Biochemical Investigation of Human DNA Polymerase Beta." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1543317539427082.

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Botelho, Heitor Cabral. "Análise dos tempos de reparo em sistemas redundantes do tipo Cold Standby com alternância." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2016. http://hdl.handle.net/10183/149187.

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Nas indústrias química e petroquímica o uso de sistemas redundantes é comum. Exceto pelos programas de lubrificação, a estratégia de manutenção adotada para estes sistemas é, principalmente, a manutenção corretiva. Os objetivos desta dissertação são, a partir do registro do histórico de falhas dos equipamentos de uma unidade fabril petroquímica e conceitos de confiabilidade, estimar o tempo limite que estes sistemas podem operar sem intervenções de manutenção, mantendo a disponibilidade do sistema em níveis adequados. Esse tempo limite foi usado para desenvolver um indicador a ser utilizado no processo de priorização das atividades de manutenção. Para atingir os objetivos foram desenvolvidas as seguintes etapas: a) revisão dos dados de confiabilidade; b) elaboração de modelagem de sistemas de bombeamento. Inicialmente foi realizada uma revisão dos dados de confiabilidade coletados pela empresa em estudo, a partir da qual se obteve análise dos problemas encontrados com os dados, sumário de procedimentos a serem adotados para cada tipo de problema e sugestões para evitar sua reincidência. Por meio dos resultados iniciais, foi elaborada a modelagem de sistemas de bombeamento, utilizando o método de Monte Carlo. Obtevese, como resultado, curvas de disponibilidade do sistema versus tempos para reparo. O método proposto é simples de ser utilizado em campo e, definida a disponibilidade desejada para o sistema redundante, permite o cálculo do máximo tempo para reparo do equipamento em falha.
In chemical and petrochemical industries redundant systems are usual. Except by lubrication programs, the maintenance strategy adopted for these systems is mainly corrective maintenance. Considering the historical failure records of the equipment of a factory and the use of reliability concepts, the goal of this work is to estimate the maximum time that these systems can operate without maintenance interference, while keeping the system availability on adequate levels. This maximum time was used to develop an indicator to be used in the process of prioritization of maintenance activities. To achieve these goals, the following steps have been developed: a) reliability data review; b) elaboration of a pumping system model. Initially, a review of the reliability data collect at the studied company was performed, from which an analysis of the problems encountered at these data, a summary of procedures to be adopted for each type of problem, and suggestions to avoid its recurrence were established. As a consequence of first results, a model for each pumping system using the Monte Carlo method was developed and availability curves of the system versus time to repair were obtained. The proposed method is simple to use in the field and, considering the desired availability for the redundant system, it allows the calculation of the maximum time to repair equipment failures.

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Laval, Quentin. "Un environnement de modélisation et d'aide à la décision pour un problème de livraison - collecte sous incertitudes : application à la PFL de l'AP-HM." Thesis, Aix-Marseille, 2017. http://www.theses.fr/2017AIXM0193.

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Ce travail de thèse s’inscrit dans le projet logistique de l’Assistance Publique Hôpitaux de Marseille. En effet l’AP-HM a ouvert une plateforme logistique en avril 2013 afin de centraliser les activités de production de repas, de stérilisation, de stockage de produits hôteliers et de blanchiment de linge. Ces produits finis sont ensuite transportés dans des contenants, grâce à une équipe de transport, vers les quatre centres hospitaliers de Marseille. Le but de cette étude de recherche est de proposer une méthode et un outil permettant d’aider l’équipe de régulation des transports pour la gestion des ressources de transport. Cette étude prend en compte la variabilité des temps de trans- port ainsi que les aléas pouvant intervenir dans le cycle de vie d’une tournée de transport.Pour cela nous commençons par réaliser un modèle de connaissance du système logistique existant grâce à la méthodologie ASCI. Nous proposons ensuite une méthode et un outil permettant la génération de planning de tournées quotidien. Cette méthode est une solution ad-hoc qui intègre la résolution d’un problème de charge- ment, la planification de véhicules et d’équipages, ainsi qu’une représentation et une mo- délisation statistique de la variabilité des temps de transports en milieu urbain. En effet, le taux de congestion quotidien peut faire varier un temps de transport du simple au double. Enfin pour la gestion des aléas, nous proposons une méthode de réparation de planning que nous modélisons grâce aux systèmes multi agents. Ce dernier point de ce travail de thèse permet, en fonction des scénarios de défaillance, de proposer la solution la plus adaptée aux équipes de transport
This thesis work is part of the logistics project of the Assistance Publique-Hôpitaux de Marseille. Indeed the AP-HM opened a logistics platform in April 2013 in order to central- ize production activities of meals, sterilization, storage product and bleaching of linen. These products are then transported in containers, thanks to a team of transport, to the four hospitals in Marseille. After consumption of the products, by healthcare units, used containers must be re- ported to the logistics platform that they are disinfected and reinstated in the production loop. The purpose of this research study is to propose a method and a tool to help the team of regulation of transport for the management of transport resources. This study takes into account the variability of the transport time and the hazards that could inter- vene in the life cycle of a tour of transport.For this we make a knowledge model of logistics system using the ASCI methodology. This model of knowledge is then validated with a simulation model. We offer then a method and a tool allowing the generation of daily tour schedule. This method is an ad - hoc solu- tion that integrates solving a problem loading, planning for vehicle and crew, as well as representation and statistical modelling of variability in the time of transport in urban areas. Indeed, the daily congestion rate can vary a transport time of one to two. Finally, for the management of the ups and downs, we propose a method of repair of planning that we model with multi agent systems. This last point of this thesis according to failure sce- narios, makes it possible to propose the best solution to the transport staff

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Manning, James. "A reliability model of a power distribution network with reference to petrochemical and gas-to-liquid plants." Diss., University of Pretoria, 2013. http://hdl.handle.net/2263/40819.

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The interruption cost for one hour of a petrochemical plant is 33 times higher than that of the average interruption cost for industrial plants across all industries. In addition to the high cost of loss of production, interruptions to the operations of petrochemical and gas-toliquid plants pose safety and environmental hazards. Thus it is necessary to better understand the reliability requirements of petrochemical and gas-to-liquid plants. This study investigated the reliability of electrical distribution networks used in petrochemical and gas-to-liquid plants compared to those used in other industrial plants. A model was developed that can be used to establish the adequacy of the reliability of a distribution network in terms of the components and network topologies used. This model was validated against data that had been collected by the IEEE and applied to an actual petrochemical plant. Over 19 years’ worth of data regarding the trips that have occurred on the distribution network of an existing petrochemical plant was collected and manipulated in order to calculate the reliability indices associated with the equipment used to make up thisRecommended Practice for the Design of Reliable Industrial and Commercial Power Systems. The cost of loss of production and the capital costs associated with increased reliability were calculated for a section of the existing petrochemical plant. The reliability associated with different network topologies that could possibly be used to supply power to this section of the plant were modelled using an appropriate software package. The resulting total cost of ownership over the life of the plant associated with each topology was then calculated in order to establish which network topology is the most appropriate for petrochemical and gas-to-liquid plants. It was concluded the components that affect the reliability of an industrial distribution network are different to those that affect a utility distribution network. These components were listed and compared. It was found that the reliability indices that were calculated for the components that affect the reliability of a petrochemical plant were similar to those provided by the IEEE. 17 out of 20 of the indices that were calculated were within the required factor of deviation. Generally the failure rates of components used in petrochemical plants were very similar to those given in the IEEE Gold Book, while the MTTR’s for the components used in petrochemical plants were found to be slightly better than those given in the IEEE Gold Book. The effect of network topology was found to be significant, with small changes in the topology of a network resulting in large variations in the reliability of the network. It was also found that the most appropriate type of network topology to use in the design of the electrical distribution network of a petrochemical plant is the dual radial network. This is the most conservative of the commonly used network topologies and is the one that is currently used in the existing plant that was studied. Due to the high cost of loss of production in petrochemical plants it was established that any incremental improvement in the reliability of the dual radial network would be beneficial to the total cost of ownership of such a plant. Such incremental improvement of the reliability of the distribution network could be cost effectively achieved by adopting a conservative maintenance strategy and the establishment of a conservative spares inventory. Before this study was undertaken, there was no literature around the reliability of electrical distribution networks that focused specifically on petrochemical and gas-to-liquid plants. This study produced a set of reliability indices and a model that electrical engineers can use in the reliability analysis of petrochemical and gas-to-liquid plants. Furthermore it shows that, because the cost of loss of production in petrochemical plants is so high, the most conservative distribution network design and maintenance philosophies should always be used. distribution network. These reliability indices were compared to those given by the IEEE
Dissertation (MEng)--University of Pretoria, 2013.
gm2014
Electrical, Electronic and Computer Engineering
unrestricted

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Labiyi, Femi Gbenga. "The Implementation of Total Productive Maintenance (TPM) InManufacturing Company : A Case Study of XYZ Plastics Manufacturing Company in Nigerian." Thesis, Högskolan i Borås, Akademin för textil, teknik och ekonomi, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-23298.

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The purpose of this thesis is to implement Total Productive Maintenance (TPM) in Nigeria Plastics Manufacturing Company. Manufacturing companies round the world pay huge amount of money for purchasing new equipments to boost their production however nothing or little is done to achieve or obtain full output from the machine for which it is intended to do. Small losses in time or deviations from planned or calculated capability are taken as usual machine performance. But currently as a result of improved capability levels and demand of quality product at lower prices, purchasing latest machine/equipment is not a way out unless it is completely used. Total Productive Maintenance (TPM) is a method that involve everybody totally, from high management to all workers to implement a complete maintenance program for all machine/equipment during its life. This method ends up in most effectiveness of tools, equipment, virtuously improved workers, tidy up working area, neat and clean working environment. A structure is going to be developed with the potential of evaluating the impact of implementing total productive maintenance within. By evaluating the result or outcome of Total Productive Maintenance (TPM), manufacturing companies can create sensible/smart decisions to improve the potency and standard of the machine, equipment and also the product on XYZ Plastics Manufacturing Company in Nigerian.

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Chen, Yachuan. "Episodic Perspectives of Wireless Network Dependability." Ohio University / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1142279334.

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37

Gilk, Jiří. "Návrhy na zlepšení hospodaření s dlouhodobým majetkem." Master's thesis, Vysoké učení technické v Brně. Fakulta podnikatelská, 2012. http://www.nusl.cz/ntk/nusl-223503.

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This dissertation solves the problems with management of capital goods in the company FORMIRA, s.r.o. The dissertation is elaborated from the analysis of present situation in the plant, whereas the heed is oriented to the most important areas, especially the organization and service activity and maintenance of assets. The result of performed analysis is the identification weak points. Proposals are submitted in the second part of the dissertation, in order to solve the problems found by presented analysis. The economical evaluation of the proposals and determinations of assumptions for the application of extended results to the company use is performed at the end of the dissertation.

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Vaalamo, Maarit. "Matrix metalloproteinases and their inhibitors in normal and aberrant wound repair : expression patterns of collagenases-1 and -3, stromelysins-1 and -2, matrilysin, metalloelastase and TIMPs-1, -2, -3 and -4 in healing cutaneous wounds and in chrome ulcers of the skin and the intestine." Helsinki : University of Helsinki, 2000. http://ethesis.helsinki.fi/julkaisut/laa/kliin/vk/vaalamo/.

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Tieber, Michael. "Studie řízení zásob ve vazbě na výrobní proces." Master's thesis, Vysoké učení technické v Brně. Fakulta podnikatelská, 2008. http://www.nusl.cz/ntk/nusl-377356.

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This master’s thesis deals with problems of inventory management in the International Repair Centre for Symbol Technologies Czech Republic s.r.o.. Actual inventory management is described with a focus on materials planning, storage and evidence of inventory movements using information database systems. A part of the thesis is also an analysis of inventory categories from several different aspects. The purpose of the master’s thesis is to submit suitable suggestions of how to improve existing inventory management processes.

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Slámová, Martina. "Návrhy na zlepšení hospodaření s dlouhodobým hmotným majetkem ve firmě." Master's thesis, Vysoké učení technické v Brně. Fakulta podnikatelská, 2015. http://www.nusl.cz/ntk/nusl-224879.

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This thesis solves issues of management with long term material property in the company H&P plast, limited liability Company, which is engaged in the manufacturing plastic products and forms. The first part of thesis contains theoretical basis and total analysis of the company. It is focused on long term material property, its care and maintenance. On the basis of analysis weaknesses are identified in the company. In the second part of thesis solutions are suggested, which is lead to improvement and optimization current situation. Finally proposals are evaluated in economic terms.

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Sen, Satish Kumar. "Interactions between circadian clocks and feeding behaviour." Thesis, Strasbourg, 2018. http://www.theses.fr/2018STRAJ041.

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Le système circadien muti-oscillant est constitué de l'horloge suprachiasmatique (SCN), l'horloge principale dans l'hypothalamus antérieur, et de nombreuses horloges périphériques. L'horloge SCN synchronise les horloges périphériques situées dans chaque organe. L'horloge SCN est une horloge circadienne auto-entretenue qui maintient les rythmes quotidiens comportementaux, physiologiques et neuroendocriniens. Les donneurs de temps (zeitgebers), tels que lumière et nourriture, sont des synchroniseurs puissants, respectivement pour le SCN et les horloges périphériques. La thèse visait à mieux comprendre les interactions entre les horloges circadiennes et le comportement alimentaire chez les espèces nocturnes. Nous avons montré dans la première et la seconde partie que l'alimentation ultradienne affecte les horloges centrales et périphériques chez la souris et le rat. Dans la première étude, nous avons conclu que l'alimentation ultradienne chez la souris a un impact majeur sur la sortie de l'horloge SCN et sur l'horloge périphérique dans le foie, tandis que dans la seconde étude, l'alimentation ultradienne chez le rat n'a eu pas d'impact sur l'horloge SCN, mais il a modifié les horloges périphériques et le métabolisme des lipides. Dans la troisième partie, nous avons montré des effets différentiels du régime alimentaire et de la restriction alimentaire temporelle sur les horloges périphériques du tissu adipeux brun et du muscle squelettique. Dans la quatrième partie, nous avons démontré un rôle du gène d'horloge Rev-erbα dans le comportement alimentaire et le métabolisme énergétique en comparant des souris porteuses d’une délétion de Rev-erbα, soit globale, soit limitée au système nerveux central. L’ensemble de ces études révèle l'interdépendance des horloges circadiennes et du comportement alimentaire, ainsi que leurs effets sur le métabolisme énergétique
The muti-oscillatory circadian system consists of the suprachiasmatic clock (SCN) the master clock, located above the optic chiasm of the anterior hypothalamus, and many peripheral clocks. The SCN clock synchronizes the other peripheral oscillators located in each organ. The SCN clock is a self-sustaining circadian oscillator maintaining the daily behavioural, physiological, and neuroendocrine rhythms. The zeitgebers such as light and food are potent synchronizers for the SCN and other peripheral clocks. The thesis was aimed to understand different aspects of the interactions between circadian clocks and feeding behaviour in nocturnal species. We showed in the first and second parts that the ultradian feeding affects the central and peripheral clocks in mice and rats. In the first part, we concluded that the ultradian feeding in mice has major impacts on the SCN clock output and the peripheral clock in the liver, while in the second part ultradian feeding in rats does not have impact on the SCN clock but it affects peripheral clocks and lipid metabolism. In the third part, we showed the differential effects of diet and time restricted feeding in brown adipose tissue and skeletal muscle peripheral clocks. In the fourth part, we showed the role of clock gene Rev-erbα on feeding behaviour and energy metabolism by comparing between global and brain specific knock-out mice. The present studies reveal the interdependency of the circadian clocks and feeding behaviour, and their effects on whole-body metabolism

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Babykina, Evgénia. "Modélisation statistique d'événements récurrents. Exploration empirique des estimateurs, prise en compte d'une covariable temporelle et application aux défaillances des réseaux d'eau." Thesis, Bordeaux 2, 2010. http://www.theses.fr/2010BOR21750/document.

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Dans le contexte de la modélisation aléatoire des événements récurrents, un modèle statistique particulier est exploré. Ce modèle est fondé sur la théorie des processus de comptage et est construit dans le cadre d'analyse de défaillances dans les réseaux d'eau. Dans ce domaine nous disposons de données sur de nombreux systèmes observés durant une certaine période de temps. Les systèmes étant posés à des instants différents, leur âge est utilisé en tant qu'échelle temporelle dans la modélisation. Le modèle tient compte de l'historique incomplet d'événements, du vieillissement des systèmes, de l'impact négatif des défaillances précédentes sur l'état des systèmes et des covariables. Le modèle est positionné parmi d'autres approches visant à l'analyse d'événements récurrents utilisées en biostatistique et en fiabilité. Les paramètres du modèle sont estimés par la méthode du Maximum de Vraisemblance (MV). Une covariable dépendante du temps est intégrée au modèle. Il est supposé qu'elle est extérieure au processus de défaillance et constante par morceaux. Des méthodes heuristiques sont proposées afin de tenir compte de cette covariable lorsqu'elle n'est pas observée. Des méthodes de simulation de données artificielles et des estimations en présence de la covariable temporelle sont proposées. Les propriétés de l'estimateur (la normalité, le biais, la variance) sont étudiées empiriquement par la méthode de Monte Carlo. L'accent est mis sur la présence de deux directions asymptotiques : asymptotique en nombre de systèmes n et asymptotique en durée d'observation T. Le comportement asymptotique de l'estimateur MV constaté empiriquement est conforme aux résultats théoriques classiques. Il s'agit de l'asymptotique en n. Le comportement T-asymptotique constaté empiriquement n'est pas classique. L'analyse montre également que les deux directions asymptotiques n et T peuvent être combinées en une unique direction : le nombre d'événements observés. Cela concerne les paramètres classiques du modèle (les coefficients associés aux covariables fixes et le paramètre caractérisant le vieillissement des systèmes). Ce n'est en revanche pas le cas pour le coefficient associé à la covariable temporelle et pour le paramètre caractérisant l'impact négatif des défaillances précédentes sur le comportement futur du système. La méthodologie développée est appliquée à l'analyse des défaillances des réseaux d'eau. L'influence des variations climatiques sur l'intensité de défaillance est prise en compte par une covariable dépendante du temps. Les résultats montrent globalement une amélioration des prédictions du comportement futur du processus lorsque la covariable temporelle est incluse dans le modèle
In the context of stochastic modeling of recurrent events, a particular model is explored. This model is based on the counting process theory and is built to analyze failures in water distribution networks. In this domain the data on a large number of systems observed during a certain time period are available. Since the systems are installed at different dates, their age is used as a time scale in modeling. The model accounts for incomplete event history, aging of systems, negative impact of previous failures on the state of systems and for covariates.The model is situated among other approaches to analyze the recurrent events, used in biostatistics and in reliability. The model parameters are estimated by the Maximum Likelihood method (ML). A method to integrate a time-dependent covariate into the model is developed. The time-dependent covariate is assumed to be external to the failure process and to be piecewise constant. Heuristic methods are proposed to account for influence of this covariate when it is not observed. Methods for data simulation and for estimations in presence of the time-dependent covariate are proposed. A Monte Carlo study is carried out to empirically assess the ML estimator's properties (normality, bias, variance). The study is focused on the doubly-asymptotic nature of data: asymptotic in terms of the number of systems n and in terms of the duration of observation T. The asymptotic behavior of the ML estimator, assessed empirically agrees with the classical theoretical results for n-asymptotic behavior. The T-asymptotics appears to be less typical. It is also revealed that the two asymptotic directions, n and T can be combined into one unique direction: the number of observed events. This concerns the classical model parameters (the coefficients associated to fixed covariates, the parameter characterizing aging of systems). The presence of one unique asymptotic direction is not obvious for the time-dependent covariate coefficient and for a parameter characterizing the negative impact of previous events on the future behavior of a system.The developed methodology is applied to the analysis of failures of water networks. The influence of climatic variations on failure intensity is assessed by a time-dependent covariate. The results show a global improvement in predictions of future behavior of the process when the time-dependent covariate is included into the model

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Su, Je-Hung, and 蘇哲弘. "Cost Analysis of the Machine Repair Problem with General Repair Times and Multiple Imperfect Coverage." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/cmf7ge.

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碩士
國立中興大學
統計學研究所
99
This thesis studies the cost analysis of the M/G/1 machine repair problem with multiple imperfect coverage. When an operating machine fails, it may be immediately detected and located with a coverage probability. We first use a recursive method and supplementary variable technique to develop steady-state analytic solutions. Numerical results of various system performance measures are provided. Next, we construct a steady-state expected cost function per machine per unit time. We use the direct search method and the Newton-Quasi to determine the optimal number of operating machines Ν and the joint optimal values of the repair rate and the coverage probability с at minimum cost. Numerical examples are presented to illustrate the Newton-Quasi method. Finally, we perform a sensitivity analysis for changes in the optimal value (Ν*, μ*, с*) along with changes in specific values of the system parameters.

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44

Chang, Ya-Dun, and 張雅惇. "Simulation Analysis for the Machine Repair Problem with General Retrial Times." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/86464038903805436596.

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碩士
國立臺北商業技術學院
資訊與決策科學研究所
102
This thesis studies a retrial machine repair problem with constant retrial policy. Each of machines breaks down follow a Poisson distribution. When a machine fails, it is sent to be repaired immediately. When a failed machine finds the repairman busy upon arrival, it enters into the orbit and waits for repair. The failed machines in the orbit form a single waiting line, and only the failed machine at the head of the orbit can retry for repair. We assume that the repair times of failed machines and the retrial times of failed machines are exponentially and generally distributed, respectively. By using the supplementary variable technique and treating the supplementary variable as the remaining retrial times, we derive the steady-state probability distributions of the number of failed machines in the orbit. We also developed some important system performances, such as the expected number of failed machines in the orbit, machine availability and operative efficiency. We construct this machine repair model using ARENA software, and execute comparative analysis through extensive computational experiments for verifying accuracy of this model. Numerical results display that the absolute error is relative small. Thus, ARENA software is a useful and powerful tool in analyzing complex machine repair problems. We construct the expected profit function per unit time. We use OptQuest in the ARENA software to search for the optimal number of operating machines in the system at the maximum profit. Finally, a sensitivity analysis is performed to investigate the influences of different system parameters and cost elements on the number of operating machines in the system and its corresponding expected profit.

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Chen, Sheng-yu, and 陳聖鈺. "Logistical support scheduling for emergency repair work after a major disaster under stochastic travel times." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/33534344783620249824.

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碩士
國立中央大學
土木工程研究所
98
Natural disasters are inevitable and inflict devastating effects, in terms of human injuries and property damage. These damages can disrupt the traffic and lifeline systems, obstructing the operation of rescue machines, rescue vehicles, ambulances and relief workers. In practice, not only the repair work teams rescue the disaster area, but also supply work teams support the logistic to the repair work teams. If the demand of repair work teams is not supplied in time, the schedule of repair work would be delayed, which will not only affect the rescue efficiency but can also increase human injuries. Most of the logistical models in the past were formulated with the average travel times, meaning that stochastic disturbances arising from variations in vehicle travel times in actual operations were neglected. In the worst case scenario, where vehicle travel times fluctuate wildly during daily operations, the planned schedule could be disturbed enough to lose its optimality. Hence, we employ network flow techniques, with the objective of minimizing the total system cost, as well as the emergency repair schedule and related operating constraints, to construct a logistical support scheduling model under stochastic travel times. Then, we modified the variable travel time parameters in the stochastic supply work scheduling model as fixed variable to develop a deterministic scheduling model to help the authorities for planning effective logistical support schedules. In addition, we also develop a simulation-based evaluation method to evaluate the schedules obtained from the manual method, the deterministic and the stochastic scheduling models, in simulated real world operations. Our model is formulated as an integer multiple-commodity network flow problem with side constraints which is characterized as NP-hard. To efficiently solve realistically large problems occurring in practice, we use a problem decomposition technique and greedy algorithm, coupled with the use of a mathematical programming solver CPLEX, to develop a heuristic algorithm. Finally, to evaluate the model and the solution algorithm in practice, we perform a case study using real data of the 1999 Chi-Chi earthquake in Taiwan. The test results show that the models and the solution algorithm are better than actual operations and would be useful for logistical support scheduling under stochastic travel times.

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劉怡均. "Optimal Redundancies for Availability of Series Systems with Warm Standby Components and General Repair Times." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/03336278614742048808.

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碩士
國立中興大學
應用數學系
92
Abstract In this thesis, we study the availability analysis of three different series system configurations with warm standby components and general repair times. The time-to-failure for each of the primary and warm standby components is assumed to be exponentially distributed with respective parameter λ and α. This thesis presents a recursive method, using the supplementary variable technique and treating the supplementary variable as the remaining repair time, to develop the steady-state probability distribution of the number of working components in the system. We develop the explicit expressions for the steady-state availability, for three configurations and perform comparisons. For all three configurations, comparisons are made for specific values of distribution parameters and of the cost of the components. The configurations are ranked based on availability and cost∕benefit ratio, for three various repair time distributions: exponential, 3-stage Erlang, and deterministic, where benefit is availability. Keywords：availability, cost-benefit, series system, general distribution, recursive method, supplementary variable technique.

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Lu, Bo-Rong, and 盧柏蓉. "Comparative Analysis of System with Warm Standbys, Detection Delay, Standby Switching Failure, Reboot Delay and General Repair Times." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/23148983440460320740.

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碩士
國立中興大學
應用數學系所
96
In this thesis, we discuss the unavailability characteristics among four different configurations with warm standby units in which detection delay, standby switching failures and reboot delay are considered. The four configurations are studied under the assumption that the time-to-breakdown and time-to-repair of active (or standby) units are exponentially and generally distributed, respectively. The detection rate and the reboot rate are assumed to be exponentially distributed with parameter and , respectively. It is assumed that the process in switching a standby unit to be an active unit may experience a failure probability of q. We provide a systematic matrix method, using the supplementary variable technique to develop the steady-state unavailability, UAv, for four configurations and perform comparisons with three various repair time distributions, such as exponential, k-stage Erlang and deterministic. The sensitivity analyses for UAv with each parameter of the system are also studied.

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HSAIO, PO-YUAN, and 蕭博元. "Shortening Repair Time In The Motor Repair Industry Use Genetic Algorithm." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/2dh4zr.

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碩士
中華大學
工業管理學系
107
Motors are necessary parts for the majority of electrical instruments, such as air-conditioners, elevators, vehicles and medical equipment. Motors rely on electricity to provide energy for these instrument because they could not be operational without a running motor. Recently, because of technology advances and human needs, the composition of motors becomes increasingly complex, and its variety is getting larger and larger. Such a situation not only increase the difficulty in arranging the operations for motor maintenance, but also often delay the completion time, influencing the normal business functions of the motor owners. Besides, the motors could be down because of constant running, which could cause damages of peripheral components. Consequently, the maintenance cost could considerably increase. Besides, as the variety of motors is getting large, additional maintenance techniques would be required, and so are manpower. As a result, it becomes difficult in managing technically unstable personnel and prolonging the maintenance time could often happen. Therefore, arranging the maintenance processes and keep the due dates in order are the purpose of this study. Genetic algorithms will be employed to resolved the above-stated problems and maintenance time reduction is expected. The proposed model will be evaluated by the real operational data from several motor maintenance shops or companies, and the experimental results will be tested in other ones.

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Chen, Guo-Fen, and 陳國分. "Using HMI to Do Repair Notification at Real Time and Design of Equipment Repair System." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/839e5x.

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碩士
國立虎尾科技大學
機械與機電工程研究所在職專班
102
In recent years, progress in increasing the mechanical automation, which makes the production efficiency. However, most of the factories have a lot of automated machines, but there is no good repair system, repair manuals too single machine, making the finishing inconvenient. When a fault, it will always be arguing, if the operator didn’t say cleary, or too many paper records, making the finishing inconvenient. In this paper, System design of machine maintenance notification in human-computer interface with ProFace and GP-Pro EX software, which allows the operator to issue a repair notice in the machine, and ProServer software can collect information to repair the system database, and the data show on the web. Repair systems’s web page using ASP.Net with VB language and build program RepairNPX monitoring software to communicate with ProServer software. When the Repair information is recorded in the database that the message will appear on the page, engineers can log in to the registration and Repair the system for maintenance, after the end, engineers can record in maintenance mode and annotation data bank. In the future, it can count the Repair records to design CBR, and calculate the damage cycle parts to design and calculate maintenance cycle of parts inventory.

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Chen, Yen-Nien, and 陳彥年. "Service Time Optimization Models for Outsourcing Warranty Repair." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/08371747006659560485.

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博士
臺灣大學
商學研究所
95
Many branders have utilized post-sale service as a tool to increase profit and build up their competitive advantage as the business faces fiercely competition in recent years. Based on current practices of branders, for example in mobile phone industry, branders now more often outsource their post-sale service of failure products to some repair service providers by signing service level agreement (SLA). These repair service providers may shorten repair service time, adapt different repair service strategy, or extend their service warranty period to improve their business performance based on the premise of service level agreement which must be satisfied. This study intends to derive an optimal repair service time under these constraints of maximum acceptable repair service time and minimum acceptable repair service level set by branders when branders have strongly bargaining power. Finally, the sensitivity analysis of parameters on optimal repair service time and corresponding profit are also performed. Our results show that (1)service providers need to reset maximal acceptable repair service time of customers to maximize its profit if repair service time constraint set by branders is longer than optimal repair service time. (2)the incentive function set by branders must be with repair service time. (3)optimal repair service time of service providers is shorter and profit is higher if the minimum acceptable repair service level set by branders is looser given that the brander provides incentive mechanism to encourage service providers to shorten its repair service time. (4)when failure rate and repair service rate are the same, both will be positively correlated to profit, but no significant implication is explored between both rates and optimal repair service time. (5)service providers choose mixed repair service strategy to maximize its profit if the ratio (replacement service cost/repair service cost) is less than , otherwise, they use repair service strategy to repair failed items.

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Dissertations / Theses on the topic 'Times to repair'

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