Dissertations / Theses on the topic 'Switch failures'
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Velagapudi, Alekhya. "Time Series Event Analysis of Pooled Multiyear Telecommunication Outages." Ohio University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1470824497.
Full textSullivan, John F. "Network fault tolerance system." Link to electronic thesis, 2000. http://www.wpi.edu/Pubs/ETD/Available/etd-0501100-125656.
Full textMhangwane, Shushu Rirhandzu Comfort. "Predicting early and late first-line antiretroviral therapy virologic failure, and switch to second-line therapy in a military population in South Africa." Diss., University of Pretoria, 2018. http://hdl.handle.net/2263/64177.
Full textDissertation (MSc)--University of Pretoria, 2018.
HJF- Phidisa project
Pharmacology
MSc
Unrestricted
Kobza, John E. "The significance of transients following failures and repairs in packet-switched networks." Diss., Virginia Tech, 1993. http://hdl.handle.net/10919/40098.
Full textPh. D.
Jalili, Hassankiadeh Seyedahmad. "Failure analysis of railway switches and crossings for the purpose of preventive maintenance." Thesis, KTH, Transportvetenskap, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-52614.
Full textLuedtke, Elin. "Minimizing Transformer No-Load Losses at Hydropower Plants : A Study of Effects from Transformer Switch-Off During Stand-by Operation." Thesis, Uppsala universitet, Institutionen för fysik och astronomi, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-447635.
Full textSack, Michael N. "The energy substrate switch during cardiac development, with the onset of cardiac hypertrophy and the transition to heart failure. : delineation and characterisation of gene regulatory mechanisms : "changing concepts of metabolic regulation in the h." Doctoral thesis, University of Cape Town, 2000. http://hdl.handle.net/11427/3457.
Full textDou, Zhifeng. "Sûreté de fonctionnement des convertisseurs - Nouvelles structures de redondances pour onduleurs sécurisés à tolérance de pannes." Thesis, Toulouse, INPT, 2011. http://www.theses.fr/2011INPT0096/document.
Full textIn all these traditional industries, or in more sensitive sectors and high technology, it appears that the safe operation of power systems becomes a critical and strategic area essential. In the area of application that focuses, design dependability and now rests primarily on an approach to reliability of components used, the use of close protection, monitoring alarms and management stop / reset / recovery. In our view, this approach is incomplete quickly when electrical safety and absolute continuity of a permanent mission should be carried out simultaneously in the presence of an internal failure of sensitive functions for low and medium power (eg, orders and bodies actuation of vehicles) or highly critical (nuclear). In this area, topologies and failure modes are at the heart of the problem. In this paper, we will focus primarily on the inverters and choppers structures at two levels of voltage (single-cell arm, <1kV), with simple configuration and multiphase parallel, although the concepts are presented, as examples, partially extrapolated to the structures of three voltage levels (arms multicellular) and rectifier (low-frequency phase control and high-frequency switching PWM). We will highlight the need to limit the intensity of these failures and to electrically isolate the defective cell and symmetrically of this inverter by multipole devices, passive or spontaneous breaking mixed cut ordered in the form of fuses integrated and distributed of multi-channel passive isolators, to imagine and develop. We will show that this process of isolation of the last backup is needed to connect, form series or parallel to the defective cell, a cell rescue in passive redundancy. The cell structure backup connection pooled by spontaneous (automatic) is especially promising as detailed in our eyes because of its simplicity and its integrability. Next, we present the isolation technologies fuse (not included, miniatures, CMS and multilayer chip fuse), their characteristics, their current limitations and operating in a switching cell test. A methodology and design of symmetrical two-way fuse (dual-fuse) on FR4 PCB - Copper will be presented in Comsol ™ and evaluated initially in static thermal IR. A passive two-way switch, relatively original material for integrating energy embedded in FR4 substrate, will be presented and fully dimensioned plans on electrical, thermal and mechanical also using finite element simulations in Comsol ™. Another aspect of exploratory analysis, mainly experimental, or to characterize the failure modes of bullets and casings ultimate power compared between the technologies of encapsulation by epoxy resin (standard discrete case) and a silicone gel (module) is provided under conditions of stress controlled and reproducible. This step is necessary to characterize the resistive mode of a chip based on faulty stresses and stability over time of the residual strength according to the nature of the encapsulant, ie the very sustainability of this failure mode. A mixed-encapsulant resin - gel will be presented and characterized, providing an excellent compromise for medium power applications. Positive results and little known today, will allow us to exploit in the next chapter, this property of stable ohmic mode of the chip failed in a structure to aid automated connection series interesting. In the end, we will detail the demonstrator prototype and introduced to the context with which we will validate the isolation structures and prototypes fuses the property of stable ohmic mode highlighted in the aspect of technological analysis of selected devices. These results allow us to refine the solutions adopted for specifications and guide future management strategy of defects whether internal or external to the topology. Supervisor digital device - sensor for the detection and reconfiguration of internal control orders will be assessed
Soares, Nielson. "Técnicas de aprendizado de máquina não supervisionado para a prevenção de falhas em máquinas de chave." Universidade Federal de Juiz de Fora (UFJF), 2018. https://repositorio.ufjf.br/jspui/handle/ufjf/6513.
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CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
As máquinas de chave são equipamentos eletromecânicos de grande importância em uma malha ferroviária. A ocorrência de falhas nesses equipamentos pode ocasionar interrupções das ferrovias e acarretar potenciais prejuízos econômicos. Assim, um diagnóstico precoce dessas falhas pode representar uma redução de custos e um aumento de produtividade. Essa dissertação tem como objetivo propor um modelo preditivo, baseado em técnicas de inteligência computacional, para a solução desse problema. A metodologia aplicada compreende o uso de técnicas de extração e seleção de características baseada em testes de hipóteses e modelos de aprendizado de máquina não supervisionado. O modelo proposto foi testado em uma base de dados disponibilizada por uma empresa ferroviária brasileira e se mostrou eficiente ao constatar como críticas as operações realizadas próximas à operação classificada como falha.
Railroad switch machines are important electromechanical equipment in a railway network, and the occurrence of failures in such equipment can cause railroad interruptions and lead to potential economic losses. Thus, an early diagnosis of these failures can represent a reduction of costs and an increase in productivity. This dissertation aims to propose a predictive model, based on computational intelligence techniques, to solve this problem. The applied methodology includes the use of features extraction and selection techniques based on hypothesis tests and unsupervised machine learning models. The proposed model was tested in a database made available by a Brazilian railway company and proved to be efficient when considering as critical the operations performed close to the operation classified as failure.
Woolston, C. P. "A method of increasing capacity of an electricity distribution network through predictive modelling and intelligent protection." Thesis, Queensland University of Technology, 2000. https://eprints.qut.edu.au/36121/1/36121_Woolston_2000.pdf.
Full textNiu, Shiqin. "Conception, optimisation et caractérisation d’un transistor à effet de champ haute tension en Carbure de Silicium." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEI136/document.
Full textSilicon carbide (SiC) has higher critical electric field for breakdown and lower intrinsic carrier concentration than silicon, which are very attractive for high power and high temperature power electric applications. In this thesis, a new 3.3kV/20A SiC-4H JFET is designed and fabricated for motor drive (330kW). This breakdown voltage is beyond the state of art of the commercial unipolar SiC devices. The first characterization shows that the breakdown voltage is lower (2.5kV) than its theoretical value. Also the on-state resistance is more important than expected. By means of finite element simulation the origins of the failure are identified and then verified by optical analysis. Hence, a new layout is designed followed by a new generation of SiC-4H JFET is fabricated. Test results show the 3.3kV JFET is developed successfully. Meanwhile, the electro-thermal mechanism in the SiC JFETs under short circuit is studied by means of TCAD simulation. The commercial 1200V SIT (USCi) and LV-JFET (Infineon) are used as sample. A hotspot inside the structures is observed. And the impact the bulk thickness and the canal doping on the short circuit capability of the devices are shown. The physical models validated by this study will be used on our 3.3kV once it is packaged
Melle, Samuel. "Analyse et modélisation des phénomènes de chargement de diélectriques dans les MEMS RF : application à la fiabilité prédictive de micro-commutateurs électromécaniques micro-ondes." Phd thesis, Université Paul Sabatier - Toulouse III, 2005. http://tel.archives-ouvertes.fr/tel-00011359.
Full textHsueh, Yen Hsien, and 薛彥賢. "Factors that Cause New Product Failures in a SME: A Case Study of Multifunction Light Switch." Thesis, 2019. http://ndltd.ncl.edu.tw/cgi-bin/gs32/gsweb.cgi/login?o=dnclcdr&s=id=%22107CGU05627019%22.&searchmode=basic.
Full textChiang, Wen-Ping, and 江文平. "Benefit Analysis of Distribution Automation Switches Applied to the System Failure Handling." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/87084111500047959891.
Full text國立彰化師範大學
電機工程學系
101
Recently, with highly Taiwan's industrial development, the requirement for power quality and reliability is getting more stringent. Taiwan Power Company has thus been employing distribution automation switch system to actively enhance the restoration efficiency to improve power supply reliability and power quality increasing customer satisfaction and reducing losses. This paper introduces the distribution automation switching system architecture and their existing types, and briefly explains communication systems. With employing the least squares method to predict the optimal load distribution; the fault detection function can effectively reduce the power failure area, shorten power restoration time. In addition, by analyzing the quantitative data related to operations of the restoration capacity and quality of power supply, the benefits of installing distribution automation switching system is ascertained. The number of feeder trips can only be achieved with partial effectiveness for the factors of nature disturbance (thunder harm, typhoons, etc.); thus, its improvement can be further studied.
Poboka, Dane Michael. "Preparation, interference and task switching: using distributional analysis and cognitive modelling estimates to extend the FTE theory." Thesis, 2017. http://hdl.handle.net/1959.13/1335830.
Full textFor more than two decades, the processes involved in task switching have been extensively investigated and numerous theories proposed attempting to explain task switch phenomena, such as switch costs, preparation effects and residual switch costs (Grange & Houghton, 2014b). A range of experimental paradigms have been employed to demonstrate the key factors that influence performance; from endogenous mechanisms related to cognitive control and executive functioning, through to task priming, interference and decay processes. I begin this thesis by providing an overview of significant task switch theories, paradigms and findings to illustrate the breadth of existing task switch research. Following this, I present a series of experiments that employ distributional analysis to investigate anticipatory preparation and proactive interference effects on task switch performance. The experiments lead to the proposal of a descriptive, activation driven model of performance, which is tested using specific experimental manipulations. The results indicate the importance of design parameters and how these can affect responding based on strategic and structural task switch related processes. Finally, I investigate the Failure to Engage (FTE) account of residual switch costs (De Jong, 2000) and replicate research that challenges this theory (Brown, Lehmann & Poboka, 2006). The results guided an extension of FTE that was tested in a further experiment and shown to be able to accommodate the effects of interval manipulations as well as both task and cue switching. I then apply a new modelling approach to obtain direct estimates of the probability of preparation and conclude that De Jong’s insights about preparation failure provide a tractable framework for understanding many aspects of cognitive control, including explaining aspects of all of the four major task-switching phenomena identified by Monsell (2003).
SANGARÉ, Mohamed Ndongo. "Cohorte de patients vivant avec le VIH et ayant de la résistance prouvée ou présumée : analyse des changements de traitement pour une trithérapie contenant deux inhibiteurs nucléosidiques de la transcriptase inverse (INTI) avec du dolutégravir ou du ténofovir/abacavir avec un troisième agent." Thesis, 2020. http://hdl.handle.net/1866/25537.
Full textSignificant progress has been made in treatment for people living with HIV (PLHIV) with the development of increasingly effective antiretroviral (ARV) therapy, safe with good tolerability. However, clinicians can sometimes face treatment challenges related to the monitoring of PLHIV whose HIV could carry genetic mutations conferring resistance to treatments either because of a history of virologic failure or because of previous exposure to mono/bitherapy to nucleoside reverse transcriptase inhibitors (NRTIs) (suboptimal therapy that was provided before the era of triple therapy). In these patients, clinicians can sometimes try less studied combinations in the hopes to better control viral load or reduce side effects in these patients. Therefore, this thesis by articles had three objectives aiming to evaluate less studied therapies that are used in these patients. The first objective (Paper 1) was to determine whether the efficacy of ARV regimen with dolutegravir in stable patients (whose viral load is controlled) varied in the presence of a history of virologic failure or with a previous exposure to suboptimal therapy regimen. The second objective (Paper 2) was to study virologic outcome after switching to dolutegravir compared to remaining on a boosted protease inhibitor (PI/r) regimen in stables PLHIV with prior documented virologic failure or exposure to mono/dual NRTI. Finally, the third objective (Paper 3) was to compare the risk of virologic failure for PLHIV who have previous documented virologic failure or prior exposure to suboptimal therapy taking an ARV therapy composed of abacavir/tenofovor (ABC/TDF) with a third agent of a different class, versus an ARV regimen composed of a standard backbone also with a non-NRTI third agent. We used data from the Quebec HIV cohort which brings together clinical information from 10,219 PLHIV followed in four clinical care centers in Montreal including the “Clinique de médecine urbaine du Quartier Latin (CMUQL)”, “Clinique médicale l’Actuel (CMA)”, the “Centre hospitalier de l'Université de Montréal (CHUM)” and the “McGill University Health Center (MUHC)”. A restriction to some patients in the cohort was made with regards to each objective of this thesis. Patients with an undetectable viral load who had received therapy with dolutegravir +2 NRTI from 2013 were selected for the objective 1. A Cox proportional hazard model with propensity score was used to compare the virologic outcome of patients on dolutegravir according to the exposure. For objective 2, patients with an undetectable viral load with an history of documented virologic failure or exposure to suboptimal therapy who were on PI/r + 2 NRTI from 2014 were selected. A marginal structural Cox model was used to measure the effect of switching to dolutegravir +2 NRTI compared to those who remained on PI/r + 2 NRTI therapy. For objective 3, patients with a documented virologic failure or exposure to suboptimal therapy in standard backbone (abacavir/lamivudine, tenofovir disoproxil/emtricitabine, tenofovir disoproxil/lamivudine) with another agent from January 01, 2006 were selected. A Cox proportional multivariate model was used to compare the virologic outcome of patients who switched to a non-standard regimen including ABC/TDF therapy versus those who remained on standard backbone. The article 1 suggested similar virologic efficacy of dolutegravir in stables patients with or without an history of documented virologic failure or exposure to suboptimal therapy (adjusted Hazard Ratio (aHR)=0,84 (95%CI: 0,35 - 2,01)). In article 2, no evidence of an increased risk of virologic failure was found in stables patients who had a regimen switched to dolutegravir compared to those who maintained their regimen with PI/r in patients who have had previous virologic failure or exposure to suboptimal therapy (aHR=0,57 (95%CI: 0,21 - 1,52)). In article 3, a non-significant reduction in the risk of virologic failure with the non-standard backbone including ABC/TDF was found compared to standard backbone (aHR=0,45 (95%CI: 0,06 - 3,36)). In conclusion, the results of this thesis first suggested no effect of the presence of previous virologic failure or exposure to suboptimal therapy on the efficacy of dolutegravir in stables patients. In addition, the results showed that the switch to dolutegravir +2 NRTI for patients with an undetectable viral load on PI/r +2NRTI regimen can be considered despite the presence of proved or suspected NRTI resistance mutation. These results are of great importance as they should lead to changes the clinical guidelines for the use of dolutegravir in stable patients. On the other hand, our results failed to show a significant advantage to the use of the backbone ABC/TDF instead of standard backbones in patients with prior documented virologic failure or previous exposure to suboptimal therapy.