Dissertations / Theses: 'Patterns of failure'

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Wolforth, Ian Philip. "Specification and use of component failure patterns." Thesis, University of Hull, 2010. http://hydra.hull.ac.uk/resources/hull:4455.

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Safety-critical systems are typically assessed for their adherence to specified safety properties. They are studied down to the component-level to identify root causes of any hazardous failures. Most recent work with model-based safety analysis has focused on improving system modelling techniques and the algorithms used for automatic analyses of failure models. However, few developments have been made to improve the scope of reusable analysis elements within these techniques. The failure behaviour of components in these techniques is typically specified in such a way that limits the applicability of such specifications across applications. The thesis argues that allowing more general expressions of failure behaviour, identifiable patterns of failure behaviour for use within safety analyses could be specified and reused across systems and applications where the conditions that allow such reuse are present.This thesis presents a novel Generalised Failure Language (GFL) for the specification and use of component failure patterns. Current model-based safety analysis methods are investigated to examine the scope and the limits of achievable reuse within their analyses. One method, HiP-HOPS, is extended to demonstrate the application of GFL and the use of component failure patterns in the context of automated safety analysis. A managed approach to performing reuse is developed alongside the GFL to create a method for more concise and efficient safety analysis. The method is then applied to a simplified fuel supply and a vehicle braking system, as well as on a set of legacy models that have previously been analysed using classical HiP-HOPS. The proposed GFL method is finally compared against the classical HiP-HOPS, and in the light of this study the benefits and limitations of this approach are discussed in the conclusions.

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Polat, Berna. "Failure patterns of new ventures : a survival analysis and performance implications /." Thesis, Connect to this title online; UW restricted, 2005. http://hdl.handle.net/1773/8739.

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McNew, Gregory J. "An examination of the patterns of failure in defense acquisition programs." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/67565.

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Thesis (S.M. in Engineering and Management)--Massachusetts Institute of Technology, Engineering Systems Division, System Design and Management Program, 2011.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 213-217).
The history of acquisition reform dates back to the Revolutionary War era, and recommendations and actions to reform the Department of Defense's acquisition system continue today. Common themes emerge from the recommendations of countless Acts, Studies, Panels, and Commissions over the past 30 years, pointing to areas that appear to have the most impact on the system. Despite these actions and recommendations, issues remain at the program execution level, resulting in increased cost and delays in fielding needed capabilities. This work focuses on three areas. A comprehensive Literature Review of acquisition reform activities was conducted. This generated a list of common themes and focus areas that are associated with less than successful program outcomes. Following this, a series of ten patterns of behavior (acquisition archetypes) postulated for software programs developed by Carnegie Mellon University's Software Engineering Institute were examined for applicability to the larger Department of Defense acquisition system and to determine their relationship to acquisition reform actions. As part of this effort, a survey of acquisition personnel was conducted to determine the relevance of these patterns of behavior. Based on these foundational works, the final step examined the results of the survey to answer four research questions. First, the survey results were analyzed to determine if the patterns of behavior were present with general and statistical relevance. The second question attempted to determine if the patterns of behavior led to measurable cost and/or schedule growth if they were present in the respondent's program. Third, the postulated root causes for the behaviors were compared to the common themes from acquisition reform activities to determine alignment. Finally, the survey results were analyzed to see if the patterns of behavior correlated to a particular program size, lead service, or "joint" program status. The findings show that the patterns of behavior are present in Department of Defense acquisition programs, and some do lead to measurable cost and/or schedule growth when identified. Acquisition Reform activities have been targeted at the areas that are reported as root causes of the behaviors, and one of the ten patterns of behavior does correlate with "joint" program status.
by Gregory J. McNew.
S.M.in Engineering and Management

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Dharmasaroja, Atipong. "Efficient modelling of failure envelopes and load patterns in aircraft structures." Thesis, Queen's University Belfast, 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.695327.

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Due to the dynamically-varying nature of aircraft loading scenarios, a large number of global load cases are generated which must be analysed in a Global Finite Element Model (GFEM) to obtain the internal load paths going into each substructure. Analysing all load cases is often not possible due to computational constraints, so that substantial engineering judgement in load case down-selection is required. One innovation developed by QUB to reduce the number of load cases is to use Singular Value Decomposition (SVD) to derive a smaller set of characteristic loads which represent all the global load distributions. This research focuses on developing the SVD based load development process by studying factors that could affect the accuracy and proposes some robust error quantification methods suitable for different scenarios. The major downstream benefit of the process is that the analysis results for this set of characteristic loads can be superimposed to create the internal load distributions resulting from all the original load cases. The method is also used in sensitivity analysis for gradient based optimisation and shows a very large reduction in computational effort. When the SVD is performed at the local structure level, a few internal load characteristic patterns, which represent all internal loads, can also be identified. Another major development in this work is that the failure envelope can be constructed in this reduced dimensional load space. The resulting surface defines critical failure constraints under any loading. The novel parameterisatlon and adaptive mesh refinement techniques have been employed to efficiently construct the failure surface of the industry standard structural assessment tools, which are treated as a black box. The failure envelope therefore provides valuable insights into the structures, failures and loads. Moreover, the down-selection process or constraint filtering can be performed very quickly using the information from this envelope.

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Archdeacon, Alyssa Lyn. "Generating Targetable Areas for Improving Malnutrition Status among 2-5 Year Olds." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1517308923555154.

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Berwick-Emms, Patricia E. "Classroom patterns of interaction and their underlying structure: a study of how achievement in the first year of school is influenced by home patterns of interaction." Thesis, University of Canterbury. Education, 1989. http://hdl.handle.net/10092/1066.

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This study attempts to answer the question of why some children fail while others succeed in the first year of school when they appear to have at least average abilities and to come from family environments which seem, on the surface at least, to provide similar developmental opportunities. The researcher observed in ten, four-year-old children's homes over a period of four days for each child and followed these intensive home observations with three-monthly, informal interviews with adult family members. Each child was observed in school intensively, on entry to school and every three months following entry until six years of age. Informal interviews were conducted with the class teachers every three months. During the 'intensive' home and school observations continuous hand-written narrative recordings of natural communication incidents were made of all the oral language and activities of the focal child, and of the language and activities of other children and adults when what they said and did was in the vicinity of the focal child. Notes were made of the location, atmosphere, body language, people present, and focal objects throughout the time of the observations. Field notes were made each night after every home, school or pre-school visit. Each child was tested with a battery of tests on entry into school at five years, at five-and-a-half years and at six years. The gathering of these different data meant a wide variety of information about the child's total ecological environment was gathered. A variety of ways for examining the data for a relationship between the behaviours and social experience of the child which occurred at home and measures of achievement in school were explored. These included a variety of language variables (e. g. exposure to question types, statement types, amount of talk) and measures of variables related to socia-economic status and home environmental factors (e.g. the HOME Scale, Caldwell & Bradley, 1979). Al though some of these variables were significantly correlated with school achievement, it was not clear that the problem of why some children succeeded in school while others failed had been satisfactorily solved. A more detailed analysis of the data was carried out which differed from most other psychological or educational studies in that it focused on the underlying structures of the natural socio-linguistic patterns of interaction in both home and school first year classrooms. The task was to describe observable social interaction in terms of the underlying structures which characterised the home subcultural experience of the children and the sub-cultural learning (acculturation) required of the children in order to successfully adapt to the school environment. The theory generated to explain this complex problem was adapted from a theory sometimes termed script theory, or schema theory. It was developed into a framework which could deal with both children's present school experience and the children's past experience of the structure of meaningful social interactions. The results showed that the underlying structure of patterns of interaction (schema) which the children brought with them from home to school did indeed cause failure for some children at school. The children's experience of patterns of interaction in the homes which were like school patterns of interaction correlated 0.91 with achievement in school. The greater the variety of school-like patterns of interaction occurring in the homes the greater a child's achievement rate was likely to be. This study has implications for classroom organisation, for the structure of classroom patterns of interaction and for young people who come from home ecological environments which are significantly different from the present classroom environment. It is argued that children are our nation's most important resource and we need to examine with great care what we are doing to promote alternative classroom environments.

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Harris, Kelly, and Kelly Harris. "Cardiac Rehabilitation for Heart Failure Patients: An Evaluation of Knowledge and Practice Patterns of Nurse Practitioners." Diss., The University of Arizona, 2016. http://hdl.handle.net/10150/621285.

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Heart failure (HF) is a complex, debilitating disease that affects approximately 6.5 million Americans (Ades et al., 2013). HF is a large reason for hospital readmissions, and subsequently, a major contributor to rising health care costs. Unfortunately, there is no cure for HF, but various interventions such as cardiac rehabilitation (CR) have been employed to help patients manage the symptoms. However, the lack of patients ever being referred to cardiac rehabilitation is disturbing. Healthcare providers play an essential role in providing education about heart failure and CR, and thus should be knowledgeable about these principles themselves. Therefore, the aim of this project is to evaluate data from a survey sent to nurse practitioners (NPs) regarding whether HF patients are being referred to CR appropriately, and if barriers are limiting use of CR programs. This was a descriptive, nonexperimental study with a survey design seeking to understand if NP providers are following evidence-based guidelines when treating HF patients and if providers consider CR programs to be an appropriate treatment tool. A survey questionnaire was distributed to NPs who are members of Coalition of Arizona Nurses in Advanced Practice (CAZNAP). Data from 27 surveys were used for analysis. Results showed that nurse practitioner respondents felt they had a good understanding of heart failure education and diagnosis. A majority also considered CR to be a useful tool for HF patients, and all agreed that health care providers affect CR enrollment and participation rates. A mere nine respondents (33%) reported being introduced to the outcomes and benefits of CR in their graduate education. Findings also confirmed previous work suggesting that providers are not adequately referring HF patients to CR, as 33% of NPs reported they have never referred a patient to CR. With respect to these findings, it is important to identify methods to assist providers with proper education about CR and its referral methods. As supported by the literature review, improved referral rates to CR can lead to better management and health outcomes for HF patients. Therefore, further research is needed to identify interventions that promote increased CR referral rates.

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Usami, Shunsuke. "Expression Patterns of miRNA-423-5p in the Serum and Pericardial Fluid in Patients Undergoing Cardiac Surgery." Kyoto University, 2016. http://hdl.handle.net/2433/215398.

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Savage, Henry Oluwasefunmi. "Early detection of decompensation of chronic heart failure using a non-contact monitor of nocturnal respiratory patterns." Thesis, Imperial College London, 2014. http://hdl.handle.net/10044/1/24577.

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Heart failure affects 1-2% of the adult population in the United Kingdom and accounts for the majority of hospitalisations in patients with cardiovascular disease. The financial implications are enormous as it consumes 1-2% of the national health care budget with 70% of these costs relating to hospitalisation expenses. Prevention of these admissions may be possible by detecting early signs of decompensation in patients with chronic heart failure (CHF) and instituting interventions that may steer the course of disease back to stability without the need for a hospital inpatient stay. Further, Sleep Disordered Breathing (SDB) and in particular Central Sleep Apnoea (CSA) is found in patients with CHF and at any symptomatic stage of the condition. This may be associated with Cheyne-Stokes Respiration (CSR), which has been shown to be an independent predictor of mortality. In the first study of this thesis, I investigated the accuracy of the SleepMinderTM (SM) device; which is a non-contact monitor of nocturnal respiratory patterns; in diagnosing SDB by deriving measures of the Apnoea Hypopnea Index (AHI) and percentage overnight CSR from the SM signals. I found that SM was good in terms of diagnostic accuracy with an area under receiver operator characteristic curve (ROC) of 0.82 (p=0.02) for an AHI threshold >15, but only moderately so for % overnight CSR>0, with an area under ROC curve of 0.72 (p=0.06). In the second study, I examined the changes that occur in SM derived respiratory parameters over a long period of monitoring and found that the AHI, quantity of CSR, Total Sleep Time (TST) and Respiratory Rate (RR) were highly variable with Intra-Class Correlation (ICC) measures of 0.32, 0.39, 0.25, 0.36 respectively over a period of 12 months. Relying on data from a year rather than a single night resulted in misclassification of patients into a different severity group of SDB during 35% of the follow up period and placed patients into a different treatment group during 21% of this period. I also observed that a high proportion (59%) of patients studied had a mean AHI that was consistently above the accepted threshold for treatment (AHI>15). This was consistent even over a shorter follow up period of 2 weeks suggesting that a single night measure of the AHI may not be a sufficient risk assessment of SDB in heart failure patients. In the final study, I have investigated the predictive value of the SleepMinderTM for acute decompensation of heart failure (ADHF) using algorithms derived from its signals. I found that the SM was not accurate for this purpose, performing with a sensitivity and specificity of 0.38 and 0.71, respectively. In summary this study has demonstrated that the SleepMinderTM device provides a novel screening method, which is convenient for the detection of sleep disordered breathing in patients with CHF. It performs with a good diagnostic accuracy and is acceptable to these patients due to its non-contact operation. Algorithms derived from its signals however cannot be used to predict acute decompensation of chronic heart failure. Further, longitudinal analyses of nocturnal respiratory patterns in these patients have demonstrated that the Apnoea Hypopnea Index (AHI) is highly variable over a prolonged period of monitoring and a mean value rather that a single night measurement may be a more appropriate risk assessment tool for SDB. This requires confirmation.

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Sakai, Kenshi, Shrinivasa K. Upadhyaya, Pedro Andrade-Sanchez, and Nina V. Sviridova. "Chaos emerging in soil failure patterns observed during tillage: Normalized deterministic nonlinear prediction (NDNP) and its application." AMER INST PHYSICS, 2017. http://hdl.handle.net/10150/624079.

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Real-world processes are often combinations of deterministic and stochastic processes. Soil failure observed during farm tillage is one example of this phenomenon. In this paper, we investigated the nonlinear features of soil failure patterns in a farm tillage process. We demonstrate emerging determinism in soil failure patterns from stochastic processes under specific soil conditions. We normalized the deterministic nonlinear prediction considering autocorrelation and propose it as a robust way of extracting a nonlinear dynamical system from noise contaminated motion. Soil is a typical granular material. The results obtained here are expected to be applicable to granular materials in general. From a global scale to nano scale, the granular material is featured in seismology, geotechnology, soil mechanics, and particle technology. The results and discussions presented here are applicable in these wide research areas. The proposed method and our findings are useful with respect to the application of nonlinear dynamics to investigate complex motions generated from granular materials. (C) 2017 Author(s).

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Aswani, A. D. "The importance and mechanism of mitochondrial damage associated molecular patterns (DAMPs) in the pathogenesis of trauma haemorrhage induced inflammation and organ injury." Thesis, Queen Mary, University of London, 2016. http://qmro.qmul.ac.uk/xmlui/handle/123456789/18405.

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Trauma is a leading cause of death worldwide with 5.8 million deaths occurring yearly. Almost 40% of trauma deaths are due to bleeding and occur in the first few hours after injury. Of the remaining severely injured patients up to 25% develop a dysregulated immune response leading to multiple organ failure (MOF). Despite improvements in trauma care, the morbidity and mortality of this condition remains very high. Massive traumatic injury can overwhelm endogenous homeostatic mechanisms even with prompt treatment. The underlying mechanisms driving MOF are also not fully elucidated. As a result, successful therapies for trauma-related MOF are lacking. Trauma causes tissue damage that releases a large number of endogenous damage-associated molecular patterns (DAMPs). Mitochondrial DAMPs released in trauma, such as mitochondrial DNA (mtDNA), could help to explain part of the immune response in trauma given the structural similarities between mitochondria and bacteria. MtDNA, like bacterial DNA, contains an abundance of highly stimulatory unmethylated CpG DNA motifs that signal through Toll-like receptor (TLR)-9 to produce inflammation. MtDNA has been shown to be highly damaging when injected into healthy animals causing acute organ injury to develop. Elevated circulating levels of mtDNA have been reported in trauma patients but an association with clinically meaningful outcomes has not been established in a large cohort. The first aim of this PhD thesis was to determine whether mtDNA released after trauma haemorrhage is sufficient for the development of MOF. Secondly, I then aimed to determine the extent of mtDNA release with varying degrees of tissue injury and haemorrhagic shock in a clinically relevant rodent model. My final aim was to determine whether neutralising mtDNA at a clinically relevant time point in vivo would reduce the severity of organ injury in this model.

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Leonard, Cheryl May. "An Investigation of Patterns of Adolescent Driving Behaviors Resulting in Fatal Crashes and Their Implications on Policy." ScholarWorks, 2016. https://scholarworks.waldenu.edu/dissertations/3111.

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The purpose of this quantitative study was to investigate whether there is a statistical relationship between accident-related factors including use of drugs or alcohol, speeding, driver distractions, gender, driver drowsiness, practice of dysfunctional driving maneuvers, and use of occupant protection devices, and fatal vehicle crashes among young teen drivers. Secondary archival data from 84 North Carolina crashes occurring between 2009 and 2013 and involving young teen drivers between the ages of 15 and 18 years were obtained from North Carolina Department of Motor Vehicles Form 349 crash reports. These data were analyzed using chi-square tests for goodness-of-fit, chi-square tests for independence, and z-tests for proportions. The study found statistically significant associations between gender (p <.019), speeding (p < .001), practice of dysfunctional driving maneuvers (p < .001), and non-use of occupant protection devices (p < .001) and teen crash fatalities. The implications of this study for positive social change include recommendations to the State of North Carolina to enact legislative action related to driver education for new drivers, with the anticipated result of reducing traffic fatalities when a teenage driver is involved in an accident. In order to counteract deadly dysfunctional driving maneuvers on the part of young teen drivers, it was recommended that State driver education curricula be expanded to include exposure to more real world, on-the-road supervised driving experience conducted under more varied conditions and that high school driver education facilities be upgraded to include skid pads for student driving practice. Further research relating to the supervised implementation and verification of the requirement of the 50 hours of adult-supervised driving experience for Graduated Driver Licensure was also recommended.

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Parrinello, Antonino. "A rate-pressure-dependent thermodynamically-consistent phase field model for the description of failure patterns in dynamic brittle fracture." Thesis, University of Oxford, 2017. https://ora.ox.ac.uk/objects/uuid:c6590f4f-f4e2-40e3-ada1-49ba35c2a594.

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The investigation of failure in brittle materials, subjected to dynamic transient loading conditions, represents one of the ongoing challenges in the mechanics community. Progresses on this front are required to support the design of engineering components which are employed in applications involving extreme operational regimes. To this purpose, this thesis is devoted to the development of a framework which provides the capabilities to model how crack patterns form and evolve in brittle materials and how they affect the quantitative description of failure. The proposed model is developed within the context of diffusive interfaces which are at the basis of a new class of theories named phase field models. In this work, a set of additional features is proposed to expand their domain of applicability to the modelling of (i) rate and (ii) pressure dependent effects. The path towards the achievement of the first goal has been traced on the desire to account for micro-inertia effects associated with high rates of loading. Pressure dependency has been addressed by postulating a mode-of-failure transition law whose scaling depends upon the local material triaxiality. The governing equations have been derived within a thermodynamically-consistent framework supplemented by the employment of a micro-forces balance approach. The numerical implementation has been carried out within an updated lagrangian finite element scheme with explicit time integration. A series of benchmarks will be provided to appraise the model capabilities in predicting rate-pressure-dependent crack initiation and propagation. Results will be compared against experimental evidences which closely resemble the boundary value problems examined in this work. Concurrently, the design and optimization of a complimentary, improved, experimental characterization platform, based on the split Hopkinson pressure bar, will be presented as a mean for further validation and calibration.

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Haydock, Paul Michael. "Service use and socioeconomic status examination in heart failure (Sussex-HF) : a single centre, retrospective study to investigate patterns of health inequality in a contemporary cohort of patients hospitalised with heart failure." Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/24646.

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OBJECTIVES: To establish the extent to which health inequality operates in a cohort of patients admitted with heart failure to a single centre serving an elderly population. DESIGN: Historical cohort study of patients admitted with a first coded presentation of heart failure. SETTING: Single district general hospital on the South-East coast of England. PARTICIPANTS: 883 patients admitted with a coded diagnosis of heart failure in the first or second diagnostic position. MAIN OUTCOME MEASURES: Mortality, readmission rates, and proportion of patients receiving recommended care. RESULTS: This was an elderly cohort, with a median age of 82.4 years. Just over half were women (51.3%), who tended to be older than men (84 vs. 80 years). Crude mortality rates at 30 days and 1 year were 17% and 38% respectively. All cause readmission at 30 days occurred in 21.3% of cases and the rate of heart failure readmission within 1 year was 35%. The most deprived patients were younger at the time of admission than those from less deprived areas (77.9 vs. 82.3 years [p=0.036]). No association was found between deprivation and mortality but rates of readmission at 30 days were higher in more deprived quintiles(p=0.01). Rates of prescription of beneficial medications were not different between quintiles of deprivation, but significantly lower rates of B-blocker and aldosterone antagonist prescription were observed in the elderly. Comorbidity and left ventricular ejection fraction were also associated with differential rates of prescribing. Provision of echocardiography and documentation of ejection fraction was strongly associated with age as was provision of specialist follow-up. CONCLUSIONS: Hospitalization for heart failure appears to occur at an earlier age in individuals from more deprived areas, but subsequent specialist management is heavily dependent on age, not level of deprivation. This may contribute to poorer outcomes in older individuals admitted with heart failure.

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Kawai, Chihiro. "Circulating extracellular histones are clinically relevant mediators of multiple organ injury." Kyoto University, 2016. http://hdl.handle.net/2433/215409.

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Final publication is available at http://ajp.amjpathol.org/
Kyoto University (京都大学)
0048
新制・課程博士
博士(医学)
甲第19583号
医博第4090号
新制||医||1014(附属図書館)
32619
京都大学大学院医学研究科医学専攻
(主査)教授小池薫, 教授中山健夫, 教授福田和彦
学位規則第4条第1項該当

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Rothmann, Lourens Johannes. "Prescribing patterns of angiotensin-converting enzyme inhibitors for the period 2001 until 2006 / Lourens Johannes Rothmann." Thesis, North-West University, 2007. http://hdl.handle.net/10394/1946.

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Safari, Ali [Verfasser], Paul [Akademischer Betreuer] Steinmann, Marc-Thorsten [Akademischer Betreuer] Hütt, and Michael [Gutachter] Zaiser. "Network models of biological systems: From patterns of brain activity to failure of biological materials / Ali Safari ; Gutachter: Michael Zaiser ; Paul Steinmann, Marc-Thorsten Hütt." Erlangen : Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 2021. http://d-nb.info/1237498988/34.

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Poudel, Bhuwan Krishna Som. "Algorithms to identify failure pattern." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for datateknikk og informasjonsvitenskap, 2013. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-23011.

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This project report was written for ?Algorithms to Identify Failure Pattern? at NTNU (Norwegian University of Science and Technology), IME (Faculty of Information Technology, Mathematics and Electrical Engineering) and IDI (Department of Computer Science).In software application, there are three types of failure pattern: point pattern, block pattern and stripe pattern. The purpose of the report is to prepare an algorithm that identifies the pattern in a software application. Only theoretical concept is written in this report. My goal is to compare these algorithms and find the efficient one.The report is written in the period from February 2012 to June 2013.

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Garde, Martínez Ainara. "Breathing pattern characterization in patients with respiratory and cardiac failure." Doctoral thesis, Universitat Politècnica de Catalunya, 2010. http://hdl.handle.net/10803/6209.

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El objetivo principal de la tesis es estudiar los patrones respiratorios de pacientes en proceso de extubación y pacientes con insuficiencia cardiaca crónica (CHF), a partirde la señal de flujo respiratorio. La información obtenida de este estudio puede contribuir a la comprensión de los procesos fisiológicos subyacentes,y ayudar en el diagnóstico de estos pacientes.
Uno de los problemas más desafiantes en unidades de cuidados intensivos es elproceso de desconexión de pacientes asistidos mediante ventilación mecánica. Más del 10% de pacientes que se extuban tienen que ser reintubados antes de 48 horas. Una prueba fallida puede ocasionar distrés cardiopulmonar y una mayor tasa de mortalidad. Se caracterizó el patrón respiratorio y la interacción dinámica entre la frecuenciacardiaca y frecuencia respiratoria, para obtener índices no invasivos que proporcionen una mayor información en el proceso de destete y mejorar el éxito de la desconexión.Las señales de flujo respiratorio y electrocardiográfica utilizadas en este estudio fueron obtenidas durante 30 minutos aplicando la prueba de tubo en T. Se compararon94 pacientes que tuvieron éxito en el proceso de extubación (GE), 39 pacientes que fracasaron en la prueba al mantener la respiración espontánea (GF), y 21 pacientes quesuperaron la prueba con éxito y fueron extubados, pero antes de 48 horas tuvieron que ser reintubados (GR).
El patrón respiratorio se caracterizó a partir de las series temporales. Se aplicó la dinámica simbólica conjunta a las series correspondientes a las frecuencias cardiaca y respiratoria, para describir las interacciones cardiorrespiratoria de estos pacientes. Técnicas de "clustering", ecualización del histograma, clasificación mediante máquinasde soporte vectorial (SVM) y técnicas de validación permitieron seleccionar el conjunto de características más relevantes.
Se propuso una nueva métrica B (índice de equilibrio) para la optimización de la clasificación con muestras desbalanceadas. Basado en este nuevo índice, aplicando SVM, se seleccionaron las mejores características que mantenían el mejor equilibrio entre sensibilidad y especificidad en todas las clasificaciones. El mejor resultado se obtuvo considerando conjuntamente la precisión y el valor de B, con una clasificación del 80% entre los grupos GE y GF, con 6 características. Clasificando GE vs. el resto de los pacientes, el mejor resultado se obtuvo con 9 características, con 81%. Clasificando GR vs. GE y GR vs. el resto de pacientes la precisión fue del 83% y 81% con 9 y 10 características, respectivamente.

La tasa de mortalidad en pacientes con CHF es alta y la estratificación de estos
pacientes en función del riesgo es uno de los principales retos de la cardiología contemporánea. Estos pacientes a menudo desarrollan patrones de respiraciónperiódica (PB) incluyendo la respiración de Cheyne-Stokes (CSR) y respiración periódica sin apnea. La respiración periódica en estos pacientes se ha asociadocon una mayor mortalidad, especialmente en pacientes con CSR. Por lo tanto, el estudio de estos patrones respiratorios podría servir como un marcador de riesgo y proporcionar una mayor información sobre el estado fisiopatológico de pacientes con CHF.
Se pretende identificar la condición de los pacientes con CHFde forma no invasiva mediante la caracterización y clasificación de patrones respiratorios con PBy respiración no periódica (nPB), y patrón de sujetos sanos, a partir registros de 15minutos de la señal de flujo respiratorio.
Se caracterizó el patrón respiratorio mediante un estudio tiempo-frecuencia estacionario y no estacionario, de la envolvente de la señal de flujo respiratorio. Parámetros relacionados con la potencia espectral de la envolvente de la señal presentaron losmejores resultados en la clasificación de sujetos sanos y pacientes con CHF con CSR, PB y nPB. Las curvas ROC validan los resultados obtenidos.
Se aplicó la "correntropy" para una caracterización tiempo-frecuencia mas completa del patrón respiratorio de pacientes con CHF. La "corretronpy" considera los momentos estadísticos de orden superior, siendo más robusta frente a los "outliers". Con la densidad espectral de correntropy (CSD) tanto la frecuencia de modulación como la dela respiración se representan en su posición real en el eje frecuencial.
Los pacientes con PB y nPB, presentan diferentesgrados de periodicidad en función de su condición, mientras que los sujetos sanos no tienen periodicidad marcada. Con único parámetro se obtuvieron resultados del 88.9% clasificando pacientes PB vs. nPB, 95.2% para CHF vs. sanos, 94.4% para nPB vs. sanos.
The main objective of this thesis is to study andcharacterize breathing patterns through the respiratory flow signal applied to patients on weaning trials from mechanicalventilation and patients with chronic heart failure (CHF). The aim is to contribute to theunderstanding of the underlying physiological processes and to help in the diagnosis of these patients.
One of the most challenging problems in intensive care units is still the process ofdiscontinuing mechanical ventilation, as over 10% of patients who undergo successfulT-tube trials have to be reintubated in less than 48 hours. A failed weaning trial mayinduce cardiopulmonary distress and carries a higher mortality rate. We characterize therespiratory pattern and the dynamic interaction between heart rate and breathing rate toobtain noninvasive indices that provide enhanced information about the weaningprocess and improve the weaning outcome.
This is achieved through a comparison of 94 patients with successful trials (GS), 39patients who fail to maintain spontaneous breathing (GF), and 21 patients who successfully maintain spontaneous breathing and are extubated, but require thereinstitution of mechanical ventilation in less than 48 hours because they are unable tobreathe (GR). The ECG and the respiratory flow signals used in this study were acquired during T-tube tests and last 30 minute.
The respiratory pattern was characterized by means of a number of respiratory timeseries. Joint symbolic dynamics applied to time series of heart rate and respiratoryfrequency was used to describe the cardiorespiratory interactions of patients during theweaning trial process. Clustering, histogram equalization, support vector machines-based classification (SVM) and validation techniques enabled the selection of the bestsubset of input features.
We defined a new optimization metric for unbalanced classification problems, andestablished a new SVM feature selection method, based on this balance index B. The proposed B-based SVM feature selection provided a better balance between sensitivityand specificity in all classifications.
The best classification result was obtained with SVM feature selection based on bothaccuracy and the balance index, which classified GS and GFwith an accuracy of 80%, considering 6 features. Classifying GS versus the rest of patients, the best result wasobtained with 9 features, 81%, and the accuracy classifying GR versus GS, and GR versus the rest of the patients was 83% and 81% with 9 and 10 features, respectively.
The mortality rate in CHF patients remains high and risk stratification in these patients isstill one of the major challenges of contemporary cardiology. Patients with CHF oftendevelop periodic breathing patterns including Cheyne-Stokes respiration (CSR) and periodic breathing without apnea. Periodic breathing in CHF patients is associated withincreased mortality, especially in CSR patients. Therefore it could serve as a risk markerand can provide enhanced information about thepathophysiological condition of CHF patients.
The main goal of this research was to identify CHF patients' condition noninvasively bycharacterizing and classifying respiratory flow patterns from patients with PB and nPBand healthy subjects by using 15-minute long respiratory flow signals.
The respiratory pattern was characterized by a stationary and a nonstationary time-frequency study through the envelope of the respiratory flow signal. Power-related parameters achieved the best results in all of the classifications involving healthy subjects and CHF patients with CSR, PB and nPB and the ROC curves validated theresults obtained for the identification of different respiratory patterns.
We investigated the use of correntropy for the spectral characterization of respiratory patterns in CHF patients. The correntropy function accounts for higher-order moments and is robust to outliers. Due to the former property, the respiratory and modulationfrequencies appear at their actual locations along the frequency axis in the correntropy spectral density (CSD).
The best results were achieved with correntropy and CSD-related parameters that characterized the power in the modulation and respiration discriminant bands, definedas a frequency interval centred on the modulation and respiration frequency peaks,respectively. All patients, i.e. both PB and nPB, exhibit various degrees of periodicitydepending on their condition, whereas healthy subjects have no pronounced periodicity.This fact led to excellent results classifying PB and nPB patients 88.9%, CHF versushealthy 95.2%, and nPB versus healthy 94.4% with only one parameter.

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Lian, Yaohua. "Firm entry and exit patterns in Chinese economy." Click to view the E-thesis via HKUTO, 2007. http://sunzi.lib.hku.hk/hkuto/record/B39005884.

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Sutherland, Hazel. "The effects of pattern and frequency of stimulation on transformation and damage in mammalian skeletal muscle." Thesis, University of Liverpool, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367198.

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Lian, Yaohua, and 連瑤華. "Firm entry and exit patterns in Chinese economy." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2007. http://hub.hku.hk/bib/B39005884.

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Riggs, Jennifer Sue. "The Influence of Home Care Nursing Visit Pattern on Heart Failure Patient Outcomes." Case Western Reserve University School of Graduate Studies / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=case1244663522.

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Gandikota, Vijai. "Modeling operating system crash behavior through multifractal analysis, long range dependence and mining of memory usage patterns." Morgantown, W. Va. : [West Virginia University Libraries], 2006. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=4566.

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Thesis (M.S.)--West Virginia University, 2006.
Title from document title page. Document formatted into pages; contains xii, 102 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 96-99).

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Zhang, Ci. "ELECTROMECHANICAL DEFORMATION AND FAILURE OF LAYERED POLYMERIC FILMS." Case Western Reserve University School of Graduate Studies / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=case1600528144785256.

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26

Ingemarsson, Philip. "The daily movement pattern and physical activity in a Swedish cohort of heart failure patients." Thesis, Örebro universitet, Institutionen för medicinska vetenskaper, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-82520.

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Zhao, Xuhui. "Automatic analysis for continuous integration test failures." Thesis, Högskolan i Gävle, Elektronik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-30187.

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CI (Continuous Integration) is a software development practice which became more and more popular in last decade. Ericsson followed the trends and used CI several years. Because of the complexity of RBS (Radio Base Station) software few levels of CI have been implemented there. In RCS (RBS Control System) module CI there are many automatic JCAT (Java Common Auto Tester) test loops running every day and some of them failed. This thesis tries to find a way to classify these test failures automatically, so efficiency and lead time can be improved. Two methods are presented and investigated in this report, rule matching and machine learning. After analysis and comparisons rule matching approach is selected because it does not require huge effort in the initial phase and rule matched data can be used as labeled data for machine learning. This approach requires manual work to add new rules continuously but with correctly defined rules the accuracy is 100%, if the rule is general it can classify one type of issue including the ones which never happen before. One analysis system is designed and implemented, and only small update is required to the result report block of the CI flow. One matching example is showed and according to estimation this method could save many man hours every year.

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Hii, Teck K. "Reducing the redundancy of financial ratios and assessing the stability of financial patterns." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2000. https://ro.ecu.edu.au/theses/1343.

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The purpose of this study was to examine the financial patterns of Australian industrial firms along the lines of Pinches et al.’s (1973; 1975) study. The financial ratios used in prior Australian corporate failure studies were used to derive a reduced set of factors that was predictive of corporate failure (e.g., Castagna & Matolesy, 1981: Booth, 1983). These factors were examined for the short – and long-term stability of these factors. The set of firms used was selected from FINSELECT database, which covered the period from 1989 to 1997. A random list of 199 Australian industrial firms that survived between 1989 and 1997 was selected. A total of thirty-one unique financial ratios were calculated based on the models derived in prior Australian failure prediction studies. These financial rations were factor analysed. The financial factors that were predictive of corporate failure were Return on Investment, Short-Term Liquidity (I and II), Financial Leverage (I and II) and Decomposition Measure.

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Losik, Len, Sheila Wahl, and Lewis Owen. "Predicting Failures and Estimating Duration of Remaining Service Life from Satellite Telemetry." International Foundation for Telemetering, 1996. http://hdl.handle.net/10150/611451.

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International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, California
This paper addresses research completed for predicting hardware failures and estimating remaining service life for satellite components using a Failure Prediction Process (FPP). It is a joint paper, presenting initial research completed at the University of California, Berkeley, Center for Extreme Ultraviolet (EUV) Astrophysics using telemetry from the EUV EXPLORER (EUVE) satellite and statistical computation analysis completed by Lockheed Martin. This work was used in identifying suspect "failure precursors." Lockheed Martin completed an exploration into the application of statistical pattern recognition methods to identify FPP events observed visually by the human expert. Both visual and statistical methods were successful in detecting suspect failure precursors. An estimate for remaining service life for each unit was made from the time the suspect failure precursor was identified. It was compared with the actual time the equipment remained operable. The long-term objective of this research is to develop a resident software module which can provide information on FPP events automatically, economically, and with high reliability for long-term management of spacecraft, aircraft, and ground equipment. Based on the detection of a Failure Prediction Process event, an estimate of remaining service life for the unit can be calculated and used as a basis to manage the failure.

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Tanwir, Sarmad. "Online Techniques for Enhancing the Diagnosis of Digital Circuits." Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/82736.

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The test process for semiconductor devices involves generation and application of test patterns, failure logging and diagnosis. Traditionally, most of these activities cater for all possible faults without making any assumptions about the actual defects present in the circuit. As the size of the circuits continues to increase (following the Moore's Law) the size of the test sets is also increasing exponentially. It follows that the cost of testing has already surpassed that of design and fabrication. The central idea of our work in this dissertation is that we can have substantial savings in the test cost if we bring the actual hardware under test inside the test process's various loops -- in particular: failure logging, diagnostic pattern generation and diagnosis. Our first work, which we describe in Chapter 3, applies this idea to failure logging. We modify the existing failure logging process that logs only the first few failure observations to an intelligent one that logs failures on the basis of their usefulness for diagnosis. To enable the intelligent logging, we propose some lightweight metrics that can be computed in real-time to grade the diagnosibility of the observed failures. On the basis of this grading, we select the failures to be logged dynamically according to the actual defects in the circuit under test. This means that the failures may be logged in a different manner for devices having different defects. This is in contrast with the existing method that has the same logging scheme for all failing devices. With the failing devices in the loop, we are able to optimize the failure log in accordance with every particular failing device thereby improving the quality of diagnosis subsequently. In Chapter 4, we investigate the most lightweight of these metrics for failure log optimization for the diagnosis of multiple simultaneous faults and provide the results of our experiments. Often, in spite of exploiting the entire potential of a test set, we might not be able to meet our diagnosis goals. This is because the manufacturing tests are generated to meet the fault coverage goals using as fewer tests as possible. In other words, they are optimized for `detection count' and `test time' and not for `diagnosis'. In our second work, we leverage realtime measures of diagnosibility, similar to the ones that were used for failure log optimization, to generate additional diagnostic patterns. These additional patterns help diagnose the existing failures beyond the power of existing tests. Again, since the failing device is inside the test generation loop, we obtain highly specific tests for each failing device that are optimized for its diagnosis. Using our proposed framework, we are able to diagnose devices better and faster than the state of the art industrial tools. Chapter 5 provides a detailed description of this method. Our third work extends the hardware-in-the-loop framework to the diagnosis of scan chains. In this method, we define a different metric that is applicable to scan chain diagnosis. Again, this method provides additional tests that are specific to the diagnosis of the particular scan chain defects in individual devices. We achieve two further advantages in this approach as compared to the online diagnostic pattern generator for logic diagnosis. Firstly, we do not need a known good device for generating or knowing the good response and secondly, besides the generation of additional tests, we also perform the final diagnosis online i.e. on the tester during test application. We explain this in detail in Chapter 6. In our research, we observe that feedback from a device is very useful for enhancing the quality of root-cause investigations of the failures in its logic and test circuitry i.e. the scan chains. This leads to the question whether some primitive signals from the devices can be indicative of the fault coverage of the applied tests. In other words, can we estimate the fault coverage without the costly activities of fault modeling and simulation? By conducting further research into this problem, we found that the entropy measurements at the circuit outputs do indeed have a high correlation with the fault coverage and can also be used to estimate it with a good accuracy. We find that these predictions are accurate not only for random tests but also for the high coverage ATPG generated tests. We present the details of our fourth contribution in Chapter 7. This work is of significant importance because it suggests that high coverage tests can be learned by continuously applying random test patterns to the hardware and using the measured entropy as a reward function. We believe that this lays down a foundation for further research into gate-level sequential test generation, which is currently intractable for industrial scale circuits with the existing techniques.
Ph. D.

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Sadeghi, Hamidreza. "Dynamic Analysis of River Embankments during Earthquakes based on Finite Deformation Theory Considering Liquefaction." 京都大学 (Kyoto University), 2014. http://hdl.handle.net/2433/188554.

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32

Butler, William David. "Spatial patterns and impacts of slope failures in five canyons of the Teton Mountains, Grand Teton National Park, Wyoming." Thesis, Kansas State University, 2013. http://hdl.handle.net/2097/15545.

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Master of Arts
Department of Geography
Richard Marston
Slope failures play a significant role as a mass movement hazard in the deglaciated mountain canyons in Grand Teton National Park. The park’s geologic and glacial histories are unique in comparison to other areas in the Rocky Mountain range. However, few detailed maps and statistical analyses of slope failures as hazards exist for park officials and visitors. The purpose of this study is to produce a comprehensive map of slope failures in five of the most accessible and commonly used canyons of the park: Cascade, Death, Garnet, Granite, and Paintbrush. This project combined fieldwork, LiDAR imagery, and GIS mapping to document five main categories of slope failures—rock slides, rock/debris flows, rock falls, and snow avalanches, as well as complex slope failures involving a combination of these categories. Summary statistics, maps, and histograms of average slope gradient, aspect, and curvature conditions as well as precipitation conditions at the “source” area of slope failures were generated for individual canyons as well as the entire study area. Snow avalanche source areas where debris flows were not readily present occurred most commonly on north and northeast facing slopes, slopes averaging a 40% gradient, and slightly convex slopes. Debris flow source areas occurred most commonly on south and southeast facing slopes, slopes with an average 42% gradient, and on slightly convex slopes. Rock fall source areas were most common on north facing slopes, slopes of an average 55% gradient, and a mostly flat curvature. Rock slide source points were most common on north facing slopes, slopes of an average 54% gradient, and flat to slightly concave slopes. Rock Mass Strength (RMS) values were sampled at a rate of every 0.5 kilometers on the hiking trail of each canyon to provide an introductory insight into rock stability conditions in each canyon. Slope failures not only impact the physical landscape of canyons in Grand Teton National Park but can affect human structures as well. Physical attributes and locations of slope failures were compared to locations of camping zones and hiking trails in the Park to determine areas of common human usage that were most susceptible to past movement events.

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Farooqi, Owais Ehtisham. "An Assessment and Modeling of Copper Plumbing pipe Failures due to Pinhole Leaks." Thesis, Virginia Tech, 2006. http://hdl.handle.net/10919/33918.

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Pinhole leaks in copper plumbing pipes are a big concern for the homeowners. The problem is spread across the nation and remains a threat to plumbing systems of all ages. Due to the absence of a single acceptable mechanistic theory no preventive measure is available to date. Most of the present mechanistic theories are based on analysis of failed pipe samples however an objective comparison with other pipes that did not fail is seldom made. The variability in hydraulic and water quality parameters has made the problem complex and unquantifiable in terms of plumbing susceptibility to pinhole leaks. The present work determines the spatial and temporal spread of pinhole leaks across United States. The hotspot communities are identified based on repair histories and surveys. An assessment of variability in water quality is presented based on nationwide water quality data. A synthesis of causal factors is presented and a scoring system for copper pitting is developed using goal programming. A probabilistic model is presented to evaluate optimal replacement time for plumbing systems. Methodologies for mechanistic modeling based on corrosion thermodynamics and kinetics are presented.
Master of Science

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34

Sause, Markus [Verfasser], and Siegfried R. [Akademischer Betreuer] Horn. "Identification of failure mechanisms in hybrid materials utilizing pattern recognition techniques applied to acoustic emission signals / Markus G. R. Sause ; Betreuer: Siegfried R. Horn." Augsburg : Universität Augsburg, 2019. http://d-nb.info/1217194711/34.

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35

Sammouri, Wissam. "Data mining of temporal sequences for the prediction of infrequent failure events : application on floating train data for predictive maintenance." Thesis, Paris Est, 2014. http://www.theses.fr/2014PEST1041/document.

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De nos jours, afin de répondre aux exigences économiques et sociales, les systèmes de transport ferroviaire ont la nécessité d'être exploités avec un haut niveau de sécurité et de fiabilité. On constate notamment un besoin croissant en termes d'outils de surveillance et d'aide à la maintenance de manière à anticiper les défaillances des composants du matériel roulant ferroviaire. Pour mettre au point de tels outils, les trains commerciaux sont équipés de capteurs intelligents envoyant des informations en temps réel sur l'état de divers sous-systèmes. Ces informations se présentent sous la forme de longues séquences temporelles constituées d'une succession d'événements. Le développement d'outils d'analyse automatique de ces séquences permettra d'identifier des associations significatives entre événements dans un but de prédiction d'événement signant l'apparition de défaillance grave. Cette thèse aborde la problématique de la fouille de séquences temporelles pour la prédiction d'événements rares et s'inscrit dans un contexte global de développement d'outils d'aide à la décision. Nous visons à étudier et développer diverses méthodes pour découvrir les règles d'association entre événements d'une part et à construire des modèles de classification d'autre part. Ces règles et/ou ces classifieurs peuvent ensuite être exploités pour analyser en ligne un flux d'événements entrants dans le but de prédire l'apparition d'événements cibles correspondant à des défaillances. Deux méthodologies sont considérées dans ce travail de thèse: La première est basée sur la recherche des règles d'association, qui est une approche temporelle et une approche à base de reconnaissance de formes. Les principaux défis auxquels est confronté ce travail sont principalement liés à la rareté des événements cibles à prédire, la redondance importante de certains événements et à la présence très fréquente de "bursts". Les résultats obtenus sur des données réelles recueillies par des capteurs embarqués sur une flotte de trains commerciaux permettent de mettre en évidence l'efficacité des approches proposées
In order to meet the mounting social and economic demands, railway operators and manufacturers are striving for a longer availability and a better reliability of railway transportation systems. Commercial trains are being equipped with state-of-the-art onboard intelligent sensors monitoring various subsystems all over the train. These sensors provide real-time flow of data, called floating train data, consisting of georeferenced events, along with their spatial and temporal coordinates. Once ordered with respect to time, these events can be considered as long temporal sequences which can be mined for possible relationships. This has created a neccessity for sequential data mining techniques in order to derive meaningful associations rules or classification models from these data. Once discovered, these rules and models can then be used to perform an on-line analysis of the incoming event stream in order to predict the occurrence of target events, i.e, severe failures that require immediate corrective maintenance actions. The work in this thesis tackles the above mentioned data mining task. We aim to investigate and develop various methodologies to discover association rules and classification models which can help predict rare tilt and traction failures in sequences using past events that are less critical. The investigated techniques constitute two major axes: Association analysis, which is temporal and Classification techniques, which is not temporal. The main challenges confronting the data mining task and increasing its complexity are mainly the rarity of the target events to be predicted in addition to the heavy redundancy of some events and the frequent occurrence of data bursts. The results obtained on real datasets collected from a fleet of trains allows to highlight the effectiveness of the approaches and methodologies used

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Shen, Chia-Hsuan. "Acoustic Based Condition Monitoring." University of Akron / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=akron1341797408.

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Vermelho, Paulo Moreira 1967. "Sistemas adesivos universais = resistência de união ao esmalte e dentina, padrão de fratura e análise ultramorfológica = Universal adhesive systems: bond strength to enamel and dentin, failure pattern and ultramorphology analysis." [s.n.], 2015. http://repositorio.unicamp.br/jspui/handle/REPOSIP/287800.

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Orientador: Marcelo Giannini
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba
Made available in DSpace on 2018-08-27T18:34:59Z (GMT). No. of bitstreams: 1 Vermelho_PauloMoreira_D.pdf: 2479320 bytes, checksum: 0d9cc50e5276a8b6e9a933c7dcd3239c (MD5) Previous issue date: 2015
Resumo: Os objetivos deste estudo foram analisar as características ultramorfológicas da interface de união dente-resina, a resistência de união ao esmalte e dentina pelo método da microtração e os padrões de fratura dos espécimes testados. Dois adesivos "universais ou multi-molde" (Scotchbond Universal, 3M ESPE e All-Bond Universal, Bisco) foram testados nos modos autocondicionantes e com condicionamento prévio e comparados aos métodos tradicionais de união ao esmalte e dentina (grupos controles) utilizando os adesivos Optibond FL (Kerr) e Clearfil SE Bond (Kuraray Noritake). Esmalte e dentina de terceiros molares humanos foram utilizados nos procedimentos adesivos, os quais foram realizados com as instruções dos fabricantes. Após a aplicação dos adesivos, um bloco de compósito foi construído em incrementos. Os dentes foram seccionados longitudinalmente para obtenção de espécimes em formato de "palitos" para o ensaio de resistência de união por microtração (n=8) e as análises em microscopia eletrônica de transmissão (MET) (n=2). Os espécimes foram testados após 24 horas ou um ano de armazenamento em saliva artificial. Para a MET, solução traçadora de nitrato de prata foi utilizada para mostrar espaços nanométricos e evidências de degradação na área de união. As superfícies fraturadas dos espécimes foram observadas em microscopia eletrônica de varredura e os dados de resistência de união analisadas pela ANOVA três-fatores, teste de Tukey e Dunnett (5%). O condicionamento prévio do esmalte aumentou a resistência de união dos adesivos universais, mas essa reduziu após o armazenamento por um ano. Os adesivos universais mostraram menor resistência de união em esmalte que o grupo controle quando utilizados no modo autocondicionante no tempo de 24 horas. Nenhuma diferença significativa foi encontrada na resistência de união em dentina nos dois tempos de avaliação quando comparados aos adesivos universais e os controle. O armazenamento por um ano reduziu a resistência de união em dentina apenas para um adesivo universal usando no modo autocondicionante. A análise fractográfica em esmalte mostrou predomínio de fraturas mistas e coesivas na camada de adesivo. Em dentina, o predomínio foram fraturas mistas, adesivas e coesivas em compósito. A observação da ultramorfologia em MET mostrou a formação de hibridização e zonas de interação entre todos os adesivos em esmalte e dentina nos dois modos de aplicação. Sinais de nanoinfiltração foram identificados na área de união dentina-resina para os adesivos Scotchbond Universal e Clearfil SE Bond após armazenamento por um ano. Os resultados sugerem que armazenamento por um ano pode reduzir a resistência de união quando os adesivos universais foram aplicados em esmalte condicionado, mas em dentina condicionada não houve redução da resistência de união, exceto para o adesivo Scotchbond Universal. No esmalte a resistência de união do grupo controle foi maior que a dos adesivos universais no modo autocondicionante. Após o armazenamento por um ano, a resistência de união dos adesivos universais em esmalte tratado com ácido fosfórico não diferiu do grupo controle. Em dentina, não foi encontrada diferença significativa entre adesivos universais e os grupos controles, independente do modo de condicionamento
Abstract: The aims of this study were to analyze the ultramorphological characteristics of tooth¿resin interfaces, the microtensile bond strength of multimode adhesive systems bonded to enamel and dentin, and the failure pattern of tested specimens. Two multimode adhesives (Scotchbond Universal, 3M ESPE; All-Bond Universal, Bisco) were tested in both self-etch and etch-and-rinse modes and compared to control groups using traditional bonding techniques (Optibond FL, Kerr; Clearfil SE Bond, Kuraray Noritake) in enamel and dentin. Enamel and dentin from third human molars were used for bonding and adhesives used according to the manufacturer¿ instructions. A composite resin block was incrementally applied to bonded surfaces, and teeth were sectioned transversely to the tooth-composite interface to obtain specimens for microtensile bond strength (n=8) and transmission electron microscopy (TEM) analysis (n=2). Specimens were tested after storage for either 24 hours or 1 year in artificial saliva. For TEM, a silver tracer solution was used to reveal nanometer-sized spaces and evidence of degradation within resin¿dentin interfaces. Fractured surfaces of tested specimens were analyzed under scanning electron microscopy. Bond strength data were analyzed by three-way ANOVA and by Tukey¿s and Dunnett¿s tests (?=5%). The acid-etching mode increased the enamel bond strength of multimode adhesives; however, bond strength decreased after storage for 1 year. Multimode adhesives showed lower enamel bond strength than the control group adhesive when used in self-etch mode for 24 hours. No significant differences in dentin bond strength were noted between multimode and control adhesives in either evaluation period. Storage for 1 year only reduced the dentin bond strength for a multimode adhesive used in self-etch mode. Mixed and cohesive-within-adhesive-layer failures were predominant in enamel. In dentin most fractures were mixed, adhesive along the dentin or enamel, and cohesive within the composite layer. TEM analysis identified hybridization and interaction zones in dentin and enamel for all adhesives and application modes. Silver impregnation was detected on dentin¿resin interfaces after storage of specimens for 1 year only with the Scotchbond Universal and Clearfil SE Bond samples. Results suggested that storage for 1 year can reduce bond strength when multimode adhesives are applied on an etched surface, but the dentin bond strength was not affected when using the etch-and-rinse mode (except for the Scotchbond Universal sample). The enamel bond strengths of the control group adhesives were higher than those obtained for multimode adhesives in the self-etch mode. After storage for 1 year, the bond strengths of multimode adhesives in etched enamel did not differ from those of the control group adhesive. In dentin, no significant difference was noted between the multimode and control group adhesives, regardless of etching mode
Doutorado
Dentística
Doutor em Clínica Odontológica

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38

Hed, Annica. "Två svenska socknar omkring nödåret 1867 : en jämförelse i befolkningsutvecklingen." Thesis, Högskolan på Gotland, Institutionen för humaniora och samhällsvetenskap, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:hgo:diva-1881.

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Uppsatsen undersöker två svenska socknar kring nödåret 1867. Syftet är att se de direkta och varierande konsekvenserna av en missväxt. Socknarna är Vilhelmina i Norrland och Döderhult i Småland och den avgränsade tidsperioden är 1865-1870. Undersökningen har gjorts utifrån församlingarnas kyrkoarkiv samt Statistiska Centralbyråns (SCB) befolkningsstatistik. Forskningsläget visar på varierande konsekvenser av nödåren 1867-1869 och ett tydligt samband med en ökad emigration till Nordamerika, men det finns ingen liknande jämförelse på mikronivå som detta arbete kan visa. I uppsatsen finns en översikt över Sverige på 1860-talet, missväxtåren samt en beskrivning över Vilhelmina och Döderhult. Stapeldiagram presenterar de två socknarnas födda, döda, utflyttade, emigrerade samt totala befolkningsmängd. Vad undersökningen kommer fram till är en negativ men icke dramatisk befolkningsutveckling som skiljer sig åt mellan de två socknarna, framförallt vad gäller emigrationerna.
This essay focuses on two swedish parishes before, during and after the famine in Sweden 1867. The purpose is to see the direct and varying impacts by crop failures. The parishes are Vilhelmina in northern Sweden and Döderhult in southern Sweden. The delimited period is 1865-1870. The study was made based on the parishes' church archives and statistics from Statistiska Centralbyrån (SCB). Previous research shows various impacts by the crop failures 1867-1869 and a clear relationship with the following mass emigrations to North America. But there is no previous comparison on a micro level and between these two different geographical areas which this essay has done. The essay gives an overview about the crop failures, Sweden in the 1860's and facts about Vilhelmina and Döderhult. Statistic bars display the number of deceased, born, expatriates, emigrants and total population. The conclusion of the study is a negative but not dramatic evolvement of the populations, and with differences between the parishes, particularly regarding the emigrations

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Soualhi, Abdenour. "Du diagnostic au pronostic de pannes des entraînements électriques." Thesis, Lyon 1, 2013. http://www.theses.fr/2013LYO10146/document.

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Le diagnostic et le pronostic de pannes des systèmes d'entraînement électriques est un enjeu majeur pour assurer la fiabilité et la sûreté de fonctionnement des outils de production notamment dans les secteurs sensibles (militaire, l'aéronautique, l'aérospatiale et nucléaire, etc.). Le travail de recherche présenté dans cette thèse vise à introduire de nouvelles méthodes de diagnostic et de pronostic des défauts d'une machine asynchrone ainsi que des roulements à rouleaux. Ces méthodes, orientées données, utilisent les données de mesure recueillies à partir de capteurs placés sur un système (machine asynchrone, roulement à rouleaux) afin de construire un vecteur de paramètres indicateur de défaut. Les méthodes de classification développées (supervisée, non supervisée) permettent de classer les observations, décrites par le vecteur de paramètres, par rapport aux différents modes de fonctionnement, connus ou inconnus du système, avec ou sans défauts. Des défauts ont été créés au rotor et aux roulements de la machine asynchrone, alimentée par le biais d'un onduleur de tension. La classification non supervisée, basée sur l'algorithme des fourmis artificielles, permet d'analyser les observations inconnues et inexplorées afin de mettre en évidence les classes regroupant les observations similaires. Cela permet d'améliorer la classification et de détecter l'apparition de nouveaux modes de fonctionnement. La classification supervisée, basée sur les modèles de Markov cachés, permet d'associer un degré d'appartenance (sous forme d'une probabilité) lors de l'affectation d'une observation à une ou plusieurs classes. Cela permet de définir un indice de fiabilité à l'affectation réalisée mais aussi de détecter l'apparition de nouveaux modes de fonctionnement. Ces méthodes ne se limitent pas qu'à diagnostiquer les défauts, elles peuvent aussi contribuer au pronostic des défauts. En effet, le pronostic peut être défini comme une extension du problème de diagnostic. La prédiction d'un défaut est réalisée par trois méthodes basées sur les modèles de Markov cachés pour la détection de l'imminence d'un défaut ainsi que par deux méthodes basées sur le système neuro-flou (ANFIS pour Adaptive Neuro Fuzzy Inference System et le neurone neuro-flou) pour estimer le temps restant avant son apparition. Des données de vieillissement d'un ensemble de roulements à rouleaux ont été utilisées afin de tester les méthodes proposées. Les résultats obtenus montrent l'efficacité de ces méthodes pour le diagnostic et le pronostic des défauts dans les entraînements électriques
Faults diagnosis and prognosis of electrical drives play a key role in the reliability and safety of production tools especially in key sectors (military, aviation, aerospace and nuclear, etc.). The research presented in this thesis aims to introduce new methods for faults diagnosis and prognosis of an induction motors and roller bearings. These methods use measured data collected from sensors placed on the system (induction motor, roller) in order to construct a feature vector which indicates the state of the system. Supervised and unsupervised classification methods are developed to classify measurements (observations) described by the feature vector compared to known or unknown operating modes, with or without failures. Defects were created in the rotor and the bearing of the induction motor, fed by a voltage inverter. The unsupervised classification technique, based on artificial ant-clustering, allows analyzing the unknown and unexplored observations to highlight classes with similar observations. This allows improving the classification and the detection of new operating modes. The supervised classification, based on hidden Markov models, allows associating a degree of similarity when we affect an observation to one or more classes. This defines a reliability index which allows the detection of new operating modes. These methods are not limited to diagnose faults; they can also contribute to the prognosis of faults. Indeed, the prognosis can be defined as an extension of the problem of diagnosis. The prognosis of faults is carried out by three methods based on hidden Markov models for the detection of an impending failure and by two methods based on the neuro-fuzzy system (ANFIS for Adaptive Neuro fuzzy Inference System and the neo-fuzzy neuron) to estimate the remaining time before its appearance. A set of historical data collected on roller bearings is used to validate the proposed methods. The obtained results show the effectiveness of the proposed methods for faults diagnosis and prognosis of electrical drives

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Abdul-Salam, Bahira. "Behaviour of shear critical frp reinforced concrete one-way slabs." Thèse, Université de Sherbrooke, 2014. http://savoirs.usherbrooke.ca/handle/11143/5352.

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Résumé : Les dalles de tabliers de ponts et des stationnements sont exposées à des environnements agressifs en particulier au Québec et en Amérique du Nord en raison de l'utilisation de sels de déglaçage et des cycles de gel-dégel. La substitution des armatures d’acier par des armatures en matériaux composites de polymères renforcés de fibres (PRF) constitue une alternative intéressante qui connait beaucoup de succès ces dernières années. Le béton armé de PRF est durable, car l’armature n’est pas sujette à la corrosion électrochimique. Aussi l’armature de PRF possède une résistance en traction élevée et est légère. En Amérique du Nord, l’utilisation des composites de PRF a suscité une attention toute particulière de la part des ingénieurs et des gestionnaires d’ouvrages. Plusieurs organismes dont des ministères de transport spécifient l’armature de PRF comme matériau structural dans leurs devis techniques pour lutter contre la corrosion et allonger la durée de service de leurs infrastructures. Les dalles en béton armé sont souvent soumises à des efforts de cisaillement critiques. Actuellement les méthodes de calcul au cisaillement (à l’effort tranchant) de dalles unidirectionnelles en béton armé de PRF différèrent d’une norme à une autre. En effet, la majorité des équations proposées dans les normes et guides de conception ont dérivées à partir de relations empiriques. Bien que des efforts de recherche considérables aient été consacrés dans ce domaine au cours de la dernière décennie, une meilleure compréhension du comportement au cisaillement et des mécanismes de rupture de dalles unidirectionnelles en béton armé de PRF est encore nécessaire. Dans cette recherche, un programme expérimental visant à étudier le comportement de dalles renforcées avec différents types de barres en PRF a été mis en place. Vingt-deux dalles unidirectionnelles en béton renforcées avec des barres de PRF ont été construites et testées en flexion a quatre points jusqu’à la rupture. Les paramètres d’étude comprennent : le type et le taux d’armature, le diamètre de la barre, l’espacement et la configuration de l’armature ainsi que la résistance en compression du béton afin d’examiner leur effet sur la résistance au cisaillement des dalles. Le comportement des dalles testées a été examiné en considérant le réseau de fissures, la charge ultime ainsi que les modes de rupture. Aussi, une base de données comprenant 203 poutres et dalles unidirectionnelles en béton armé de PRF rompues en cisaillement a été répertoriée et introduite dans les analyses. Les charges de rupture en cisaillement des dalles testées dans le cadre de cette thèse ainsi que celles de la base de données ont été comparées à celles prédites par les équations de calcul proposées par la normes canadiennes CSA S6-06/S1 et CSA S806-12, ainsi que celles des deux guides de calcul ACI 440.1R-06 et JSCE-97. Les analyses effectuées ont montré que les valeurs prédites par les équations de calcul proposées par l’ACI 440.1R-06 sont très conservatrices, alors que celles prédites par celles de JSCE-97 sont en meilleur accord avec les valeurs expérimentales. Aussi, les résultats obtenus ont montré que les équations de la nouvelle norme CSA S806-12 prédisent bien la résistance au cisaillement expérimentale. Toutefois, une amélioration de l'équation de la norme CSAS806-12, conduisant à de meilleurs résultats, est proposée. Par ailleurs, les résultats obtenus dans le cadre de cette thèse ont mené à une meilleure compréhension des mécanismes de rupture et des facteurs principaux qui contribuent à la résistance au cisaillement de dalles unidirectionnelles en béton armée de PRF. Enfin, des recommandations pour des travaux futurs y sont également formulées. // Abstract : Bridge deck and parking garage slabs are exposed to aggressive environments particularly in the North American regions resulting from the excessive use of de-icing salts. Fiber-reinforced-polymer (FRP) reinforcements have emerged as a practical and sustainable anti-corrosive reinforcing material with superior tensile strength to overcome the corrosion problem. High comfort level and increase use of the material is currently seen. Protection and regulations policies of some Public North American agencies currently include GFRP reinforcing bars as premium reinforcement. Shear behaviour in RC slabs is examined since most of the bridge deck and parking garage slabs are shear critical. However, there is still no agreement in FRP design codes and guidelines for shear strength equations. Several design code equations are still based on empirical relationships while recent developments are based on shear theories. The complex nature of shear phenomena which is influenced by many parameters, in addition to the existence of various schools of thoughts in shear, makes it difficult to find a general agreement on a unified equation. Huge research efforts are being established, however better understanding for the shear behaviour and failure mechanisms for unidirectional FRP RC slabs is still needed. In this research study, an experimental program was designed to investigate the shear behaviour of one-way concrete slabs reinforced with different types of FRP bars. A total of twenty one concrete slabs reinforced with FRP bars in addition to a steel reinforced slab were constructed and tested to failure under two-point loading. The variation in the concrete contribution to the shear strength V[subscript c] is investigated with respect to FRP reinforcement properties. Newly developed GFRP bars with high modulus, which were not previously investigated in the literature, are used. Different FRP reinforcement properties were included in the study such as reinforcement ratio, modulus of elasticity and axial stiffness, type of bars, and reinforcement configuration. Also, normal concrete and high strength concrete were considered in the research program. Analysis of the experimental results included the general behavior of the tested slabs, crack patterns, ultimate capacities, and modes of failure, load deflection relationships as well as the concrete and reinforcement strains. Test results of the present investigation indicate an influence of the reinforcement type, bar diameter, and the shear stiffness of the bars on the mode of failure and the shear strength. The experimental investigation and analysis of test results provided better understanding of concerning mechanisms of failure and factors contributing to the shear capacity of FRP RC slabs. A refined shear model to the CSA S806-12 is introduced and found to provide better results compared to the existing design codes and guidelines. The model is based on regression analysis of an experimental database. The database is assembled from twenty five different studies in addition to the present investigation. The used database includes 203 unidirectional members reinforced with FRP bars (without shear reinforcement) failing in shear. The model was evaluated through the experimental concrete shear capacities (V[subscript c exp]) of the database and found to provide good predictions. The experimental shear capacities of the database ( V[subscript c exp]) was compared to their corresponding predicted shear capacities (Vcpred ) using CSA S806-12, CAN/CSA-S6.1S1, ACI 440.1R-06, and JSCE-97. It was found that the ACI guide is very conservative. It can be noted that using this guide in its present form may reduce the economic competitiveness of fibre-reinforced polymers. JSCE recommendations are in better agreement with the test results. The Canadian CSA S806-12 equation was found to be in good fit with the experimental shear capacities.

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Sánchez, Martínez Sergio. "Multi-feature machine learning analysis for an improved characterization of the cardiac mechanics." Doctoral thesis, Universitat Pompeu Fabra, 2018. http://hdl.handle.net/10803/663748.

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This thesis focuses on the development of machine learning tools to better characterize the cardiac anatomy and function in the context of heart failure, and in particular their extension to consider multiple parameters that help identifying the pathophysiological aspects underlying disease. This advanced and personalized characterization may eventually allow assigning patients to clinically-meaningful phenogroups with a uniform treatment response and/or disease prognosis. Specifically, the thesis copes with the technical difficulties that multivariate analyses imply, paying special attention to properly combine different descriptors that might be of different nature (e.g., patterns, continuous, or categorical variables) and to reduce the complexity of large amounts of data up to a meaningful representation. To this end, we implemented an unsupervised dimensionality reduction technique (Multiple Kernel Learning), which highlights the main characteristics of complex, high-dimensional data into fewer dimensions. For our computational analysis to be useful for the clinical community, it should remain fully interpretable. We made special emphasis in allowing the user to be aware of how the input to the learning process models the obtained output, through the use of multi-scale kernel regression techniques among others.
Esta tesis se centra en el desarrollo de herramientas de aprendizaje automático para mejorar la caracterización de la anatomía y la función cardíaca en el contexto de insuficiencia cardíaca, y, en particular, su extensión para considerar múltiples parámetros que ayuden a identificar los aspectos pato-fisiológicos subyacentes a la enfermedad. Esta caracterización avanzada y personalizada podría en última instancia permitir asignar pacientes a fenogrupos clínicamente relevantes, que demuestren una respuesta uniforme a un determinado tratamiento, o un mismo pronóstico. Específicamente, esta tesis lidia con las dificultades técnicas que implican los análisis multi-variable, prestando especial atención a combinar de forma apropiada diferentes descriptores que pueden ser de diferente naturaleza (por ejemplo, patrones, o variables continuas o categóricas), y reducir la complejidad de grandes cantidades de datos mediante una representación significativa. Con este fin, implementamos una técnica no supervisada de reducción de dimensionalidad (Multiple Kernel Learning), que destaca las principales características de datos complejos y de alta dimensión utilizando un número reducido de dimensiones. Para que nuestro análisis computacional sea útil para la comunidad clínica debería ser enteramente interpretable. Por eso, hemos hecho especial hincapié en permitir que el usuario sea consciente de cómo los datos entrantes al algoritmo de aprendizaje modelan el resultado obtenido mediante el uso de técnicas de regresión kernel multi-escala, entre otras.

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Baumgarten, Lars. "Gesteinsmechanische Versuche und petrophysikalische Untersuchungen – Laborergebnisse und numerische Simulationen." Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2016. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-202612.

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Dreiaxiale Druckprüfungen können als Einstufenversuche, als Mehrstufenversuche oder als Versuche mit kontinuierlichen Bruchzuständen ausgeführt werden. Bei der Anwendung der Mehrstufentechnik ergeben sich insbesondere Fragestellungen hinsichtlich der richtigen Wahl des Umschaltpunktes und des optimalen Verlaufs des Spannungspfades zwischen den einzelnen Versuchsstufen. Fraglich beim Versuch mit kontinuierlichen Bruchzuständen bleibt, ob im Versuchsverlauf tatsächlich Spannungszustände erfasst werden, welche die Höchstfestigkeit des untersuchten Materials repräsentieren. Die Dissertation greift diese Fragestellungen auf, ermöglicht den Einstieg in die beschriebene Thematik und schafft die Voraussetzungen, die zur Lösung der aufgeführten Problemstellungen notwendig sind. Auf der Grundlage einer umfangreichen Datenbasis gesteinsmechanischer und petrophysikalischer Kennwerte wurde ein numerisches Modell entwickelt, welches das Spannungs-Verformungs-, Festigkeits- und Bruchverhalten eines Sandsteins im direkten Zug- und im einaxialen Druckversuch sowie in dreiaxialen Druckprüfungen zufriedenstellend wiedergibt. Das Festigkeitsverhalten des entwickelten Modells wurde in Mehrstufentests mit unterschiedlichen Spannungspfaden analysiert und mit den entsprechenden Laborbefunden verglichen.

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Patout, Maxime. "Evaluation des techniques pour la prise en charge diagnostique et thérapeutique de l'insuffisance respiratoire chronique A Randomized controlled trial on the effect of needle gauge on the pain and anxiety experienced during radial arterial puncture Long term survival following initiation of home non-invasive ventilation : a European study Neural respiratory drive predicts long-term outcome following admission for exacerbation of COPD : a post hoc analysis Neural respiratory drive and cardiac function in patients with obesity hypoventilation syndrome following initiation of non-invasive ventilation Polysomnography versus limited respiratory monitoring and nurse-led titration to optimise non-invasive ventilation set-up a pilot randomised clinical trial Chronic ventilator service Step-down from non-invasive ventilation to continuous positive airway pressure : a better phenotyping is required AVAPS-AE versus ST mode : a randomized controlled trial in patients with obesity hypoventilation syndrome Technological advances in home non-invasive ventilation monitoring : reliability of data and effect on patient outcomes Efficacy of a home discharge care bundle after acute exacerbation of COPD Prediction of severe acute exacerbation using changes in breathing pattern of COPD patients on home noninvasive ventilation Charasteristics and outcome of patients set up on high-flow oxygen therapy at home Trial of portable continuous positive airway pressure for the management of tracheobronchomalacia." Thesis, Normandie, 2019. http://www.theses.fr/2019NORMR115.

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L’insuffisance respiratoire chronique est un syndrome défini par une défaillance monoviscéralerespiratoire. Sa principale origine est aujourd’hui le syndrome obésité-hypoventilation qui concerne 4 à 5% des patients obèses. L’IRC est aussi le stade évolutif terminal de la bronchopneumopathie chronique obstructive qui touche 6 à 8% de la population adulte. L’incidence de ces pathologies et donc de l’insuffisance respiratoire est en augmentation constante. Dans cette thèse, nous avons évalué les nouvelles modalités diagnostiques et thérapeutiques qui pourraient améliorer la prise en charge des patients atteints d’insuffisance respiratoire chronique.Concernant la prise en charge diagnostique, nous avons montré que les données fournies par l’électromyographie de surface des muscles intercostaux, outil qui évalue le travail respiratoire, constituent un marqueur pronostique indépendant chez les patients atteints de bronchopneumopathie chronique obstructive. Nous avons également montré leur pertinence pour prédire l’efficacité clinique et l’observance à la ventilation non-invasive à domicile.Concernant la prise en charge thérapeutique, nous avons montré que l’utilisation d’un mode semi-automatisé de ventilation non-invasive a la même efficacité que celle de modes classiques en permettant une mise en place plus rapide du traitement. Nous avons également rapporté l’intérêt de l’oxygénothérapie à haut débit au domicile alors que ce traitement était utilisé jusque-là dans le seul cadre des soins intensifs. Enfin, nous avons rapporté les bénéfices de la pression positive continue au cours de l’effort chez les patients ayant une trachéobronchomalacie. Concernant le suivi des patients, nous avons montré que les données des logiciels de ventilation non invasive permettent de prédire la survenue d’une exacerbation sévère de BPCO mais que l’utilisation de la télémédecine chez les patients insuffisants respiratoires chroniques ne peut être encore pleinement intégrée dans la pratique clinique. Au cours de cette thèse, nous avons identifié de nouveaux outils physiologiques, de nouvelles modalités d’administration des traitements et de nouveaux outils de suivi à domicile, à même d’améliorer la prise en charge des patients insuffisants respiratoires chroniques
Single-organ respiratory failure defines chronic respiratory failure. Obesity hypoventilation syndrome is the main cause of chronic respiratory failure and occurs in 4 to 5% of obese patients. Chronic respiratory failure is also the end-stage evolution of chronic obstructive pulmonary disease that has a prevalence of 6 to 8% in the adult population. The incidence of these diseases increases so does the incidence of chronic respiratory failure. In this thesis, we will evaluate novel diagnostic and therapeutic modalities that could improve the care of patients with chronic respiratory failure. Regarding diagnostic modalities, we have seen that evaluating the work of breathing with surface parasternal electromyography was an independent prognostic marker in patients with chronic obstructive pulmonary disease. We have also seen that it was a relevant tool to predict the clinicalefficacy and compliance to home non-invasive ventilation. Regarding therapeutic modalities, we have shown that the use of a semi-automatic mode of non-invasive ventilation had the same efficacy of a standard mode with a shorter length of stay for its setup. We have shown the relevance and feasibility of the use of high-flow oxygen therapy in the home setting whilst it was only used in intensive care units. Finally, we have shown the benefits of continuous positive airway pressure during exertion in patients with tracheobronchomalacia. Regarding patients’ follow-up, we have shown that the use of data from built-in software could predict the onset of a severe exacerbation of chronic obstructive pulmonary disease. However, we also show that the implementation of tele-medicine in patients with chronic respiratory failure cannot be included in daily clinical practice yet. In this thesis, we have identified novel physiological tools, novel ways to administer treatments and novel follow-up tools that can improve the management of patients with chronic respiratory failure

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Moreno, Betancur Margarita. "Regression modeling with missing outcomes : competing risks and longitudinal data." Thesis, Paris 11, 2013. http://www.theses.fr/2013PA11T076/document.

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Les données manquantes sont fréquentes dans les études médicales. Dans les modèles de régression, les réponses manquantes limitent notre capacité à faire des inférences sur les effets des covariables décrivant la distribution de la totalité des réponses prévues sur laquelle porte l'intérêt médical. Outre la perte de précision, toute inférence statistique requière qu'une hypothèse sur le mécanisme de manquement soit vérifiée. Rubin (1976, Biometrika, 63:581-592) a appelé le mécanisme de manquement MAR (pour les sigles en anglais de « manquant au hasard ») si la probabilité qu'une réponse soit manquante ne dépend pas des réponses manquantes conditionnellement aux données observées, et MNAR (pour les sigles en anglais de « manquant non au hasard ») autrement. Cette distinction a des implications importantes pour la modélisation, mais en général il n'est pas possible de déterminer si le mécanisme de manquement est MAR ou MNAR à partir des données disponibles. Par conséquent, il est indispensable d'effectuer des analyses de sensibilité pour évaluer la robustesse des inférences aux hypothèses de manquement.Pour les données multivariées incomplètes, c'est-à-dire, lorsque l'intérêt porte sur un vecteur de réponses dont certaines composantes peuvent être manquantes, plusieurs méthodes de modélisation sous l'hypothèse MAR et, dans une moindre mesure, sous l'hypothèse MNAR ont été proposées. En revanche, le développement de méthodes pour effectuer des analyses de sensibilité est un domaine actif de recherche. Le premier objectif de cette thèse était de développer une méthode d'analyse de sensibilité pour les données longitudinales continues avec des sorties d'étude, c'est-à-dire, pour les réponses continues, ordonnées dans le temps, qui sont complètement observées pour chaque individu jusqu'à la fin de l'étude ou jusqu'à ce qu'il sorte définitivement de l'étude. Dans l'approche proposée, on évalue les inférences obtenues à partir d'une famille de modèles MNAR dits « de mélange de profils », indexés par un paramètre qui quantifie le départ par rapport à l'hypothèse MAR. La méthode a été motivée par un essai clinique étudiant un traitement pour le trouble du maintien du sommeil, durant lequel 22% des individus sont sortis de l'étude avant la fin.Le second objectif était de développer des méthodes pour la modélisation de risques concurrents avec des causes d'évènement manquantes en s'appuyant sur la théorie existante pour les données multivariées incomplètes. Les risques concurrents apparaissent comme une extension du modèle standard de l'analyse de survie où l'on distingue le type d'évènement ou la cause l'ayant entrainé. Les méthodes pour modéliser le risque cause-spécifique et la fonction d'incidence cumulée supposent en général que la cause d'évènement est connue pour tous les individus, ce qui n'est pas toujours le cas. Certains auteurs ont proposé des méthodes de régression gérant les causes manquantes sous l'hypothèse MAR, notamment pour la modélisation semi-paramétrique du risque. Mais d'autres modèles n'ont pas été considérés, de même que la modélisation sous MNAR et les analyses de sensibilité. Nous proposons des estimateurs pondérés et une approche par imputation multiple pour la modélisation semi-paramétrique de l'incidence cumulée sous l'hypothèse MAR. En outre, nous étudions une approche par maximum de vraisemblance pour la modélisation paramétrique du risque et de l'incidence sous MAR. Enfin, nous considérons des modèles de mélange de profils dans le contexte des analyses de sensibilité. Un essai clinique étudiant un traitement pour le cancer du sein de stade II avec 23% des causes de décès manquantes sert à illustrer les méthodes proposées
Missing data are a common occurrence in medical studies. In regression modeling, missing outcomes limit our capability to draw inferences about the covariate effects of medical interest, which are those describing the distribution of the entire set of planned outcomes. In addition to losing precision, the validity of any method used to draw inferences from the observed data will require that some assumption about the mechanism leading to missing outcomes holds. Rubin (1976, Biometrika, 63:581-592) called the missingness mechanism MAR (for “missing at random”) if the probability of an outcome being missing does not depend on missing outcomes when conditioning on the observed data, and MNAR (for “missing not at random”) otherwise. This distinction has important implications regarding the modeling requirements to draw valid inferences from the available data, but generally it is not possible to assess from these data whether the missingness mechanism is MAR or MNAR. Hence, sensitivity analyses should be routinely performed to assess the robustness of inferences to assumptions about the missingness mechanism. In the field of incomplete multivariate data, in which the outcomes are gathered in a vector for which some components may be missing, MAR methods are widely available and increasingly used, and several MNAR modeling strategies have also been proposed. On the other hand, although some sensitivity analysis methodology has been developed, this is still an active area of research. The first aim of this dissertation was to develop a sensitivity analysis approach for continuous longitudinal data with drop-outs, that is, continuous outcomes that are ordered in time and completely observed for each individual up to a certain time-point, at which the individual drops-out so that all the subsequent outcomes are missing. The proposed approach consists in assessing the inferences obtained across a family of MNAR pattern-mixture models indexed by a so-called sensitivity parameter that quantifies the departure from MAR. The approach was prompted by a randomized clinical trial investigating the benefits of a treatment for sleep-maintenance insomnia, from which 22% of the individuals had dropped-out before the study end. The second aim was to build on the existing theory for incomplete multivariate data to develop methods for competing risks data with missing causes of failure. The competing risks model is an extension of the standard survival analysis model in which failures from different causes are distinguished. Strategies for modeling competing risks functionals, such as the cause-specific hazards (CSH) and the cumulative incidence function (CIF), generally assume that the cause of failure is known for all patients, but this is not always the case. Some methods for regression with missing causes under the MAR assumption have already been proposed, especially for semi-parametric modeling of the CSH. But other useful models have received little attention, and MNAR modeling and sensitivity analysis approaches have never been considered in this setting. We propose a general framework for semi-parametric regression modeling of the CIF under MAR using inverse probability weighting and multiple imputation ideas. Also under MAR, we propose a direct likelihood approach for parametric regression modeling of the CSH and the CIF. Furthermore, we consider MNAR pattern-mixture models in the context of sensitivity analyses. In the competing risks literature, a starting point for methodological developments for handling missing causes was a stage II breast cancer randomized clinical trial in which 23% of the deceased women had missing cause of death. We use these data to illustrate the practical value of the proposed approaches

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Tsung-YenLin and 林宗彥. "Association of BOLL methylation patterns with human spermatogenic failure." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/27763594779993801963.

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碩士
國立成功大學
臨床醫學研究所
101
BOLL, a highly conserved sterility-related gene, has been shown to play a role in spermatogenesis from flies to humans. Our and other studies demonstrated that BOLL is expressed in the cytoplasm of pachytene spermatocytes and round spermatids in the human testes with normal spermatogenesis, that the expression of BOLL mRNA and protein were decreased in infertile patients with spermatogenic failure and that neither mutation nor polymorphism of BOLL gene was identified in infertile men. Therefore, epigenetic regulation of BOLL might be responsible for the decreased BOLL expression. In our previous study, by using genome-wide methylation array and cDNA microarray, we demonstrated the hypermethylation status of BOLL in the testes with hypospermatogenesis compared to the testes with normal spermatogenesis. The aim of this project was set out to explore the association of BOLL gene hypermethylation and spermatogenic failure. In addition to the results from methylation array, the CpG island (CGI) of BOLL gene was predicted in silico, and the predicted CGI contained the hypermethylation site identified from methylation array. Azoospermic patients with normal spermatogenesis and hypospermatogenesis were enrolled. The methylation status of each CpG was determined by pyrosequencing analysis after bisulfate treatment. The degree of each methylation at each CpG position was determined by the ratio of C to T incorporated during pyrosequencing (percentage of DNA methylation). The mRNA transcript levels were determined by quantitative real-time RT-PCR. The severity of spermatogenic failure was determined by spermatogenic score. Pearson product moment correlation coefficients were calculated to determine the correlation between the percentage of methylation (% methylation) and transcript level and spermatogenic score. In vitro luciferase reporter assay was used to verify the effects of hypermethylation of CGI promoter on promoter activity. The mRNA transcript levels of BOLL were significantly lower in patients with hypospermatogenesis. The amplified fragment in the promoter region of the BOLL gene was sequenced by using seven pairs of primers to analyze a total of 34 CpG sites. Of the 34 CpGs, eight showed significantly higher % methylation in hypospermatogenesis group, and significantly inverse correlation was found between CpG % methylation and transcript levels in three GpGs. For individual sequencing segment (segment 1-7), only segment 2, 3, 6 and 2+3 showed significantly higher methylation index (MtI, mean of % methylation at all CpG positions) in hypospermatogenesis, and segment 2 significantly and inversely correlated with transcript levels. Similarly, of the eight CpGs showing significantly higher % methylation in hypospermatogenesis group, significantly inverse correlation was found between CpG % methylation and spermatogenic score in seven GpGs. Of the four segments showing significantly higher MtI in hypospermatogenesis, three segments significantly and inversely correlated with spermatogenic score. In vitro luciferase reporter assay revealed that significantly decreased luciferase activity were noted in methyltransferase SssI treated constructs but not in methyltransferase HhaI treated constructs. Our results, for the first time, demonstrate that hypermethylation of CGI promoter of BOLL gene contributes to one of the causes of low expression of BOLL, which may lead to spermatogenic failure in humans.

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46

Lafreniere-Roula, Myriam. "Failure modes of centrally generated patterns : clues to the organization of the spinal central pattern generator." 2004. http://hdl.handle.net/1993/16312.

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Tseng, Wen-Li, and 曾雯莉. "The Failure Strength and Patterns of Human Degenerated Intervertebral Disc in Resisting the Hydrostatic Pressure." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/38341412961618740302.

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碩士
國立臺灣大學
醫學工程學研究所
96
Objective： To evaluate the strength of hydrostatic pressure of endplate and the spreading pattern of contrast agent in the disc. Summary of Background Data： One of the disc degeneration therapies is to inject the biomaterials, which replace or promote regeneration of nucleus into the nucleus pulposus. To determine the efficacy of this therapy and the criteria of patient selection, it is important to evaluate the hydrostatic pressure strength of endplate and the injection pattern of contrast agent in the disc. Methods：Fifteen discs from 5 cadaver thoracic and lumbar spines (aged 77-92 years, mean age: 86 years) were injected with contrast agent using the quantitative discomanometry (QD) apparatus. The injection process was scanned with cine-CT. The endplate leakage pressure, spreading pattern of contrast agent in the disc, and the correlation between leakage pressure and bone mineral density (BMD) were analyzed. To observe the grade of endplate degeneration and the leakage site of the contrast agent, the discs were sectioned along the coronal plane, and macroscopic photographed. Result：The center region of endplate (1.03±0.14mm) was the thinner than the one of periphery region (1.26±0.06mm). Spreading patterns of contrast agent in the disc included “nucleus space expansion” and “anular fissure formation”. The contrast agent was found to leak through the endplate and the anulus fibrosis. The endplate leakage pressure (0.18±0.17MPa) was lower than the anular leakage pressure (0.27±0.21MPa). The endplate and anular leakage pressure were found positively correlated with BMD. Comparing CT images to macroscopic photographies, the contrast agent leaked through the fissure and the sclerosis site of endplate. The discontinuous lines between endplate and disc in CT images may be the indication of endplate degeneration. Conclusion：Both of the endplate leakage pressure and the anular leakage pressure were correlated positively with BMD. The contrast agent spread through the anular fissure of disc, and leaked through the fissures and the sclerosis site of endplate.

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LIN, YI-XUAN, and 林翌萱. "The Spectral Analysis of Human Heartbeat-Differentiate between Congestive Heart Failure and Healthy Heartbeat Patterns." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/664web.

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碩士
東海大學
統計學系
107
In this study, we focus on the analysis of heart rate data. Two groups of healthy people and patients with congestive heart failure, respectively, were used as samples. The differences between the two groups were analyzed by spectral analysis and other statistical methods. We collected a total of 24 subjects' heartbeat data, and converted the original data interval into the number of occurrences in fixed time windows. First, the basic statistics were used to understand the data-related patterns, and then the spectral analysis was used to understand the differences between the two groups. Finally, Variance-Time-Curve were need to graphically present the number of heartbeat variability, and then obtain each VTC index, and determine whether it can distinguish the difference between the two groups by statistical methods, and evaluate the empirical analysis results. Through empirical analysis, it is found that the spectral analysis can effectively show the difference between the two groups. The VTC index test results are close to being statistically significant. It is still possible to distinguish the difference between healthy people and patients with congestive heart failure by analyzing the results.

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He, Min-Yu, and 何敏瑜. "The effect of reinforcement stiffness on the strength and failure patterns of reinforced soil retaining wall." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/12629523610523386510.

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碩士
雲林科技大學
營建工程系碩士班
96
Due to its convenience in construction method and extensibility, geosynthetics have been used as reinforcement in reinforced soil retaining wall and reinforced slope. In view of the above, a series of plane strain model test was performed in this study. The dimensions of the plane strain model wall were 250 cm (width) × 80 cm (depth) × 110 cm (height). Three types of granular sandy gravels and sand with its D50 ranging from 10.1mm to 0.4 mm were used and three types of geogrids with different stiffness were used. Monotonic vertical loading was applied in the model footing which was 85 cm apart from the facing of wall. The deformation patterns of granular soils were observed in the tests through the front transparent acryl plates. A photogrammetric analysis procedure was used to define the thickness of shear zone. Test results showed that using geogrid as reinforcement can enhance the vertical bearing capacity and reduce the lateral deformation of facing. For the case of reinforced gravel retaining wall with higher stiffness, the above behavior is more prominent. The shear zone patterns became distinct after the occurrence of peak strength and the thickness of shear zone were about 16~27 times toD50.

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Chiu, Vikki Wei-Ting, and 邱瑋婷. "Influences of family communication patterns on complaints and preferences of service failure recovery for adolescent customers." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/48383846251451877934.

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Abstract:

碩士
國立中興大學
行銷學系所
96
Complaint handling has great influence on customer retention and provides a chance for businesses to improve service quality. The research intended to reveal the linkage of family communication patterns and complaint actions for adolescent customers. The relationship between post-complaint behavior and service recovery satisfaction was discussed. A consumer survey was administered in the metropolitan area of Taipei. Stratified sampling procedure was applied following the age and gender distribution of the population between the ages of 13 to 19. Consensuses from parents were obtained prior to the survey. Based on the results of the study, adolescent customers with high concept-orientation and high socio-orientation were prone to complain for dissatisfaction. Private actions were preferred by adolescent customers to express dissatisfaction, followed by using the internet or through actions of parents. For either complainers or non-complainers, having real compensations immediately is preferred to receiving compensations for the next patronage. Adolescent preferred to have discounts, followed free desserts. The results indicated that adolescents were more straightforward and they wanted to have compensations immediately. Furthermore, service recovery satisfaction showed a positive relationship with repeat purchases. Adolescent customers who were satisfied with service or food compensations would be likely to have repeat purchases. Nevertheless, adolescents who were unsatisfied with the service or food recovery did not totally cease purchasing. Based on the results of the study, strategic marketing was suggested for marketing managers to enhance the complaint management mechanism.

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Dissertations / Theses on the topic 'Patterns of failure'

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