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Ліщенко, Наталя Володимирівна. "Підвищення продуктивності профільного зубошліфування на верстатах з ЧПК на основі адаптації елементів технологічної системи". Thesis, НТУ "ХПІ", 2018. http://repository.kpi.kharkov.ua/handle/KhPI-Press/37663.
Повний текст джерелаАнотація:
Дисертація на здобуття наукового ступеня доктора технічних наук за спеціальністю 05.02.08 – технологія машинобудування. – Національний технічний університет "Харківський політехнічний інститут", Харків, 2018.
Дисертація присвячена рішенню важливої науково-технічної проблеми підвищення продуктивності бездефектного профільного зубошліфування на верстатах з ЧПК на основі розробки відповідних технологічних передумов та підсистем проектування, моніторингу і технологічної діагностики операції, які дозволяють виконувати адаптацію елементів технологічної системи до більш високої продуктивності. Для цього розроблено методологію дослідження технологічної системи зубошліфування з використанням наукових методів моделювання, оптимізації і керування, а також відповідні технологічні передумови у вигляді комплексу цілеспрямованих методів і засобів інноваційної технології профільного зубошліфування: математичні моделі припуску для перетворення невизначеності припуску у величину відводу шліфувального круга, метод вирівнювання припуску по периферії зубчастого колеса без внесення корекції в його кутове положення, метод адаптивної правки профільного шліфувального круга тощо. Теоретично показано і практично підтверджено технологічну перевагу високопоруватих шліфувальних кругів у порівнянні зі переривчастими кругами. Виконано комплекс експериментальних досліджень і заводських випробувань, що підтвердили ефективність розроблених методів і засобів.Thesis for the degree of doctor of technical sciences on specialty 05.02.08 – manufacturing engineering. – National Technical University "Kharkiv Polytechnic Institute", Kharkiv, 2018. The thesis is devoted to solving an important scientific and technical problem of increasing the productivity of defect-free profile gear grinding on CNC machines on the basis of the development of appropriate technological preconditions and subsystems for the designing, monitoring and diagnosing of the operation, which allow adapting the elements of the grinding system to higher productivity. For this purpose a methodology is developed for researching the profile grinding system using scientific methods of modeling, optimization and control, as well as corresponding technology preconditions in the form of a set of purposeful methods and means of innovative profile grinding technology, to wit: grinding stock mathematical models for the transformation of the grinding stock uncertainty into the taking grinding wheel away from a gear to be grinded, method of the grinding stock aligning on the gear periphery without making corrections in its angular position, method of a profile grinding wheel adaptive dressing, etc. The software for these subsystems is created on the basis of the mathematical models of the temperature field with and without taking into account the effect of forced cooling. The technological superiority of high-porosity grinding wheel has been theoretically demonstrated and practically confirmed in comparison with special discontinuous wheel. Complex of experimental research and factory tests is performed for confirming the effectiveness of the methods and means developed.
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Ліщенко, Наталя Володимирівна. "Підвищення продуктивності профільного зубошліфування на верстатах з ЧПК на основі адаптації елементів технологічної системи". Thesis, Одеська національна академія харчових технологій, 2018. http://repository.kpi.kharkov.ua/handle/KhPI-Press/37665.
Повний текст джерелаАнотація:
Дисертація на здобуття наукового ступеня доктора технічних наук за спеціальністю 05.02.08 – технологія машинобудування. – Національний технічний університет "Харківський політехнічний інститут", Харків, 2018.
Дисертація присвячена рішенню важливої науково-технічної проблеми підвищення продуктивності бездефектного профільного зубошліфування на верстатах з ЧПК на основі розробки відповідних технологічних передумов та підсистем проектування, моніторингу і технологічної діагностики операції, які дозволяють виконувати адаптацію елементів технологічної системи до більш високої продуктивності. Для цього розроблено методологію дослідження технологічної системи зубошліфування з використанням наукових методів моделювання, оптимізації і керування, а також відповідні технологічні передумови у вигляді комплексу цілеспрямованих методів і засобів інноваційної технології профільного зубошліфування: математичні моделі припуску для перетворення невизначеності припуску у величину відводу шліфувального круга, метод вирівнювання припуску по периферії зубчастого колеса без внесення корекції в його кутове положення, метод адаптивної правки профільного шліфувального круга тощо. Теоретично показано і практично підтверджено технологічну перевагу високопоруватих шліфувальних кругів у порівнянні зі переривчастими кругами. Виконано комплекс експериментальних досліджень і заводських випробувань, що підтвердили ефективність розроблених методів і засобів.Thesis for the degree of doctor of technical sciences on specialty 05.02.08 – manufacturing engineering. – National Technical University "Kharkiv Polytechnic Institute", Kharkiv, 2018. The thesis is devoted to solving an important scientific and technical problem of increasing the productivity of defect-free profile gear grinding on CNC machines on the basis of the development of appropriate technological preconditions and subsystems for the designing, monitoring and diagnosing of the operation, which allow adapting the elements of the grinding system to higher productivity. For this purpose a methodology is developed for researching the profile grinding system using scientific methods of modeling, optimization and control, as well as corresponding technology preconditions in the form of a set of purposeful methods and means of innovative profile grinding technology, to wit: grinding stock mathematical models for the transformation of the grinding stock uncertainty into the taking grinding wheel away from a gear to be grinded, method of the grinding stock aligning on the gear periphery without making corrections in its angular position, method of a profile grinding wheel adaptive dressing, etc. The software for these subsystems is created on the basis of the mathematical models of the temperature field with and without taking into account the effect of forced cooling. The technological superiority of high-porosity grinding wheel has been theoretically demonstrated and practically confirmed in comparison with special discontinuous wheel. Complex of experimental research and factory tests is performed for confirming the effectiveness of the methods and means developed.
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Menjoge, Rajiv (Rajiv Shailendra). "New procedures for visualizing data and diagnosing regression models." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/61190.
Повний текст джерелаАнотація:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Sloan School of Management, Operations Research Center, 2010.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 97-103).
This thesis presents new methods for exploring data using visualization techniques. The first part of the thesis develops a procedure for visualizing the sampling variability of a plot. The motivation behind this development is that reporting a single plot of a sample of data without a description of its sampling variability can be uninformative and misleading in the same way that reporting a sample mean without a confidence interval can be. Next, the thesis develops a method for simplifying large scatter plot matrices, using similar techniques as the above procedure. The second part of the thesis introduces a new diagnostic method for regression called backward selection search. Backward selection search identifies a relevant feature set and a set of influential observations with good accuracy, given the difficulty of the problem, and additionally provides a description, in the form of a set of plots, of how the regression inferences would be affected with other model choices, which are close to optimal. This description is useful, because an observation, that one analyst identifies as an outlier, could be identified as the most important observation in the data set by another analyst. The key idea behind backward selection search has implications for methodology improvements beyond the realm of visualization. This is described following the presentation of backward selection search. Real and simulated examples, provided throughout the thesis, demonstrate that the methods developed in the first part of the thesis will improve the effectiveness and validity of data visualization, while the methods developed in the second half of the thesis will improve analysts' abilities to select robust models.
by Rajiv Menjoge.
Ph.D.
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Kuhn, Lukas [Verfasser], Michael [Akademischer Betreuer] Beetz, and Kleer Johan [Akademischer Betreuer] De. "Self-diagnosing Agent: Tight Integration of Operational Planning and Active Diagnosis / Lukas Kuhn. Gutachter: Michael Beetz ; Johan de Kleer. Betreuer: Michael Beetz." München : Universitätsbibliothek der TU München, 2011. http://d-nb.info/1014330408/34.
Повний текст джерела
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QUINTELLA, RODRIGO PACHECO MURAT DE MEIRELLES. "PROPOSAL OF DIAGNOSIS SYSTEM FOR INTERNATIONAL TRADE OPERATIONS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2004. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=4816@1.
Повний текст джерелаАнотація:
COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIORO estado do Rio de Janeiro, a segunda maior economia do Brasil, exerce forte influência na Região Sudeste nas atividades de exportação e importação, principalmente por sua estrutura portuária privilegiada. Bilhões de dólares em mercadorias são exportadas e importadas anualmente através de terminais portuários no estado. Para auxiliar o planejamento dos sistemas de transporte do estado, torna-se necessário um diagnóstico das operações de comércio exterior, assim como o uso de um sistema de informação para apoio a decisões, devido ao grande volume de dados e da complexidade do problema. Essa dissertação aborda a proposta, os testes e a implementação de um modelo de sistema de informações para o armazenamento e análise de dados referentes a operações de exportação que envolvem o estado do Rio de Janeiro e seu entorno, juntamente com um modelo de interface de consultas que possibilite o diagnóstico dessas operações. A dissertação também aborda o uso de um Sistema de Informações Geográficas para a visualização dos resultados das consultas e auxílio ao diagnóstico. O principal resultado deste trabalho é tornar disponível um sistema de informações para diagnósticos logísticos. Entre diversas constatações feitas com o uso desta ferramenta, extraídas de dados entre os anos de 1999 e 2002, estão a confirmação da necessidade de um anel rodoviário circundando a cidade do Rio de Janeiro, que o importador principal são os Estados Unidos com 18% do total exportado e que a maior parte das exportações está ligada aos produtos da indústria de petróleo.
Rio de Janeiro has the second strongest state economic movement in Brazil, as a consequence it has great influence over the Brazilian southeastern region in international trade operations, based on a privileged harbor infrastructure. Over the years, goods and products worth billions of dollars have been imported and exported through harbors located in Rio. A diagnostics of these operations is a necessary tool for the transportation systems planning in the state, as well as the use of information systems to support decision-making, since there`s a large amount of data to be handled and the ensuing complexity of the problem. This dissertation proposes, develops, tests and implements an information system model for storage and analysis of data concerning the international trade operations involving the state of Rio de Janeiro and its outskirts together with a query interface model for computer aided human diagnostics of these operations. This work also includes the use of Geographic Information Systems for visualization of query results and diagnostic assistance. The main result of this work is to make available a useful information systems tool for diagnostics in Logistics. Among various sample conclusions of a prototypical use of the tool with data in the range 1999- 2002 were: the confirmation of the need for a surrounding expressway, that the main foreign client is the US with 18% of the total and that the majority of the products belong to the Oil industry.
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Vileiniskis, Marius. "Fault detection and diagnosis methods for engineering systems." Thesis, University of Nottingham, 2015. http://eprints.nottingham.ac.uk/30402/.
Повний текст джерелаАнотація:
The main aim of this thesis is to investigate available techniques and develop a methodology for the fault detection and diagnostics for two engineering systems, namely railway point systems (RPS) and three-phase separators (TPS). The fault detection of the RPS was performed on the measured current from the motor of point operating equipment (POE). The method of One Class Support Vector Machines has been chosen as the fault detection model. Elastic similarity measures, such as edit distance with real penalties and dynamic time warping, were chosen to compare the data of POE operations. A combination of Euclidean distance and elastic similarity measures has been proposed in order to take into account the absolute values and shape properties of the two compared time series. The proposed methodology has been tested on the in-field RPS data. The results indicated that the fault detection model was able to detect abnormal values and/or shape of the time series of measured current. However, not in all cases these changes could be related to a recorded failure of RPS in the database. The fault detection of TPS was performed given the sensor readings of flow and level transmitters of TPS. The method of Bayesian Belief Networks (BBN) has been proposed to overcome the late detection of faults with the threshold based alarm technique. An approach to observe sensor readings of TPS in several adjacent time intervals and to update the prior probabilities in the BBN after inserting the sensor readings as evidence was proposed. The proposed methodology has been tested on the data obtained from a TPS simulation model. The results indicated that the fault detection and diagnostics model was able to detect inconsistencies in sensor readings and link them to corresponding failure modes when single or multiple failures were present in the TPS.
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Tonomura, Osamu. "Shape Design and Operation of Microreactors." 京都大学 (Kyoto University), 2015. http://hdl.handle.net/2433/200473.
Повний текст джерела
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Staderman, William P. "Communicating expertise in system operation and fault diagnosis to non-experts." Diss., Virginia Tech, 2003. http://hdl.handle.net/10919/27468.
Повний текст джерелаАнотація:
The use of systems that span many knowledge domains is becoming more common as technology advances, requiring expert-performance in a domain from users who are usually not experts in that domain. This study examined a means of communicating expertise (in system operation and fault diagnosis) to non-experts and furthering the understanding of expert mental models. It has been suggested that conceptions of abstract models of system-functions distinguish expert performance from non-expert performance (Hanisch, Kramer, and Hulin, 1991). This study examined the effects on performance of augmenting a simple control panel device with a model of the functions of the device, interacting with the model, and augmenting the device with graphically superimposed procedural indicators (directions). The five augmented display conditions studied were: Device Only, Device + Model, Device + Procedural Indicators, Interactive Model, and Interactive Model + Procedural Indicators. The device and displays were presented on a PC workstation. Performance measures (speed and accuracy) and subjective measures (questionnaires, NASA TLX, and structured interviews) were collected. It was expected that participants who interact with the device + procedural indicators would exhibit the shortest performance time and least errors; however, those who interacted with the simplest display (device only) were fastest and exhibited the least errors. Results of this study are discussed in terms of building a mental model and identifying situations that require a mental model.Ph. D.
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Flietstra, Bryan C. "A data mining approach for acoustic diagnosis of cardiopulmonary disease." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/45400.
Повний текст джерелаАнотація:
Thesis (S.M.)--Massachusetts Institute of Technology, Sloan School of Management, Operations Research Center, 2008.Includes bibliographical references (p. 107-111).
Variations in training and individual doctor's listening skills make diagnosing a patient via stethoscope based auscultation problematic. Doctors have now turned to more advanced devices such as x-rays and computed tomography (CT) scans to make diagnoses. However, recent advances in lung sound analysis techniques allow for the auscultation to be performed with an array of microphones, which send the lung sounds to a computer for processing. The computer automatically identifies adventitious sounds using time expanded waveform analysis and allows for a more precise auscultation. We investigate three data mining techniques in order to diagnose a patient based solely on the sounds heard within the chest by a "smart" stethoscope. We achieve excellent recognition performance by using k nearest neighbors, neural networks, and support vector machines to make classifications in pair-wise comparisons. We also extend the research to a multi-class scenario and are able to separate patients with interstitial pulmonary fibrosis with 80% accuracy. Adding clinical data also improves recognition performance. Our results show that performing computerized lung auscultation offers a low-cost, non-invasive diagnostic procedure that gives doctors better clinical utility especially in situations when x-rays and CT scans are not available.
by Bryan C. Flietstra.
S.M.
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Gabarrón, Fernández Sara. "Diagnosis, assessment and optimisation of the design and operation of municipal MBRs." Doctoral thesis, Universitat de Girona, 2014. http://hdl.handle.net/10803/145434.
Повний текст джерелаАнотація:
This thesis is based on diagnosing, assessing and optimising the design and operation of membrane bioreactors (MBR) used for treating municipal wastewater. Specifically, this thesis has been carried out within the framework of seven municipal MBR wastewater treatment plants (WWTP) located in Catalonia with the collaboration of the Catalan Water Agency. Firstly, the design and operational issues of MBRs have been diagnosed, together with determining the main operational problems related to this technology. Secondly, the optimisation strategies applied in each full-scale MBR and the resulting costs were assessed. Finally, two of the operational problems identified were exhaustively evaluated: The ragging phenomenon and the biological nitrogen removal and operational costs optimisations. The research carried out in this thesis has enabled the design and operation of the municipal MBRs to be assessed while, at the same time, presenting several optimisation strategies which will improve the operation and costs of this technologyAquesta tesi es centra en la diagnosi, avaluació i optimització del disseny i l’operació dels bioreactors de membranes (BRM) pel tractament d’aigües residuals. Concretament, l’estudi s’ha realitzat dins del marc de treball de set estacions depuradores d’aigües residuals (EDARs) municipals amb tecnologia BRM presents a Catalunya en col·laboració amb l’Agència Catalana de l’Aigua. Primerament s’ha dut a terme la diagnosi de l’estat del disseny i operació dels BRMs i s’han determinat les problemàtiques associades a aquesta tecnologia. Així mateix, s’han avaluat les estratègies d’optimització realitzades i els corresponents costos d’operació. A partir de la diagnosis realitzada, dos dels principals problemes operacionals observats s’han caracteritzat i optimitzat: El ragging i l’optimització de l’eliminació biològica de nitrogen i dels costos d’operació. La recerca presentada en aquesta tesi ha permès diagnosticar l’estat dels BRMs, alhora que ha mostrat possibles vies d’optimització que permetran millorar l’operació i els costos associats a aquesta tecnologia
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Jemwa, Gorden Takawadiyi. "Monitoring and diagnosis of process systems using kernel-based learning methods." Thesis, Stellenbosch : University of Stellenbosch, 2007. http://hdl.handle.net/10019.1/4483.
Повний текст джерелаАнотація:
Thesis (PhD (Process Engineering))--University of Stellenbosch, 2007.Dissertation presented for the degree of Doctor of Philosophy in Engineering at the University of Stellenbosch.
ENGLISH ABSTRACT: The development of advanced methods of process monitoring, diagnosis, and control has been identified as a major 21st century challenge in control systems research and application. This is particularly the case for chemical and metallurgical operations owing to the lack of expressive fundamental models as well as the nonlinear nature of most process systems, which makes established linearization methods unsuitable. As a result, efforts have been directed in the search of alternative approaches that do not require fundamental or analytical models. Data-based methods provide a very promising alternative in this regard, given the huge volumes of data being collected in modern process operations as well as advances in both theoretical and practical aspects of extracting information from observations. In this thesis, the use of kernel-based learning methods in fault detection and diagnosis of complex processes is considered. Kernel-based machine learning methods are a robust family of algorithms founded on insights from statistical learning theory. Instead of estimating a decision function on the basis of minimizing the training error as other learning algorithms, kernel methods use a criterion called large margin maximization to estimate a linear learning rule on data embedded in a suitable feature space. The embedding is implicitly defined by the choice of a kernel function and corresponds to inducing a nonlinear learning rule in the original measurement space. Large margin maximization corresponds to developing an algorithm with theoretical guarantees on how well it will perform on unseen data. In the first contribution, the characterization of time series data from process plants is investigated. Whereas complex processes are difficult to model from first principles, they can be identified using historic process time series data and a suitable model structure. However, prior to fitting such a model, it is important to establish whether the time series data justify the selected model structure. Singular spectrum analysis (SSA) has been used for time series identification. A nonlinear extension of SSA is proposed for classification of time series. Using benchmark systems, the proposed extension is shown to perform better than linear SSA. Moreover, the method is shown to be useful for filtering noise in time series data and, therefore, has potential applications in other tasks such as data rectification and gross error detection. Multivariate statistical process monitoring methods are well-established techniques for efficient information extraction from multivariate data. Such information is usually compact and amenable to graphical representation in two or three dimensional plots. For process monitoring purposes control limits are also plotted on these charts. These control limits are usually based on a hypothesized analytical distribution, typically the Gaussian normal distribution. A robust approach for estimating con dence bounds using the reference data is proposed. The method is based on one-class classification methods. The usefulness of using data to define a confidence bound in reducing fault detection errors is illustrated using plant data. The use of both linear and nonlinear supervised feature extraction is also investigated. The advantages of supervised feature extraction using kernel methods are highlighted via illustrative case studies. A general strategy for fault detection and diagnosis is proposed that integrates feature extraction methods, fault identification, and different methods to estimate confidence bounds. For kernel-based approaches, the general framework allows for interpretation of the results in the input space instead of the feature space. An important step in process monitoring is identifying a variable responsible for a fault. Although all faults that can occur at any plant cannot be known beforehand, it is possible to use knowledge of previous faults or simulations to anticipate their recurrence. A framework for fault diagnosis using one-class support vector machine (SVM) classification is proposed. Compared to other previously studied techniques, the one-class SVM approach is shown to have generally better robustness and performance characteristics. Most methods for process monitoring make little use of data collected under normal operating conditions, whereas most quality issues in process plants are known to occur when the process is in-control . In the final contribution, a methodology for continuous optimization of process performance is proposed that combines support vector learning with decision trees. The methodology is based on continuous search for quality improvements by challenging the normal operating condition regions established via statistical control. Simulated and plant data are used to illustrate the approach.
AFRIKAANSE OPSOMMING: Die ontwikkeling van gevorderde metodes van prosesmonitering, diagnose en -beheer is geïdentifiseer as 'n groot 21ste eeuse uitdaging in die navorsing en toepassing van beheerstelsels. Dit is veral die geval in die chemiese en metallurgiese bedryf, a.g.v. die gebrek aan fundamentele modelle, sowel as die nielineêre aard van meeste prosesstelsels, wat gevestigde benaderings tot linearisasie ongeskik maak. Die gevolg is dat pogings aangewend word om te soek na alternatiewe benaderings wat nie fundamentele of analitiese modelle benodig nie. Data-gebaseerde metodes voorsien belowende alternatiewe in dié verband, gegewe die enorme volumes data wat in moderne prosesaanlegte geberg word, sowel as die vooruitgang wat gemaak word in beide die teoretiese en praktiese aspekte van die onttrekking van inligting uit waarnemings. In die tesis word die gebruik van kern-gebaseerde metodes vir foutopsporing en -diagnose van komplekse prosesse beskou. Kern-gebaseerde masjienleermetodes is 'n robuuste familie van metodes gefundeer op insigte uit statistiese leerteorie. Instede daarvan om 'n besluitnemingsfunksie te beraam deur passingsfoute op verwysingsdata te minimeer, soos wat gedoen word met ander leermetodes, gebruik kern-metodes 'n kriterium genaamd groot marge maksimering om lineêre reëls te pas op data wat ingebed is in 'n geskikte kenmerkruimte. Die inbedding word implisiet gedefinieer deur die keuse van die kern-funksie en stem ooreen met die indusering van 'n nielineêre reël in die oorspronklike meetruimte. Groot marge-maksimering stem ooreen met die ontwikkeling van algoritmes waarvan die prestasie t.o.v. die passing van nuwe data teoreties gewaarborg is. In die eerste bydrae word die karakterisering van tydreeksdata van prosesaanlegte ondersoek. Alhoewel komplekse prosesse moeilik is om vanaf eerste beginsels te modelleer, kan hulle geïdentifiseer word uit historiese tydreeksdata en geskikte modelstrukture. Voor so 'n model gepas word, is dit belangrik om vas te stel of die tydreeksdata wel die geselekteerde modelstruktuur ondersteun. 'n Nielineêre uitbreiding van singuliere spektrale analise (SSA) is voorgestel vir die klassifikasie van tydreekse. Deur gebruik te maak van geykte stelsels, is aangetoon dat die voorgestelde uitbreiding beter presteer as lineêre SSA. Tewens, daar word ook aangetoon dat die metode nuttig is vir die verwydering van geraas in tydreeksdata en daarom ook potensiële toepassings het in ander take, soos datarektifikasie en die opsporing van sistematiese foute in data. Meerveranderlike statistiese prosesmonitering is goed gevestig vir die doeltreffende onttrekking van inligting uit meerveranderlike data. Sulke inligting is gewoonlik kompak en geskik vir voorstelling in twee- of drie-dimensionele grafieke. Vir die doeleindes van prosesmonitering word beheerlimiete dikwels op sulke grafieke aangestip. Hierdie beheerlimiete word gewoonlik gebaseer op 'n hipotetiese analitiese verspreiding van die data, tipiese gebaseer op 'n Gaussiaanse model. 'n Robuuste benadering vir die beraming van betroubaarheidslimiete gebaseer op verwysingsdata, word in die tesis voorgestel. Die metode is gebaseer op eenklas-klassifikasie en die nut daarvan deur data te gebruik om die betroubaarheidsgrense te beraam ten einde foutopsporing te optimeer, word geïllustreer aan die hand van aanlegdata. Die gebruik van beide lineêre en nielineêre oorsiggedrewe kenmerkonttrekking is vervolgens ondersoek. Die voordele van oorsiggedrewe kenmerkonttrekking deur van kern-metodes gebruik te maak is beklemtoon deur middel van illustratiewe gevallestudies. 'n Algemene strategie vir foutopsporing en -diagnose word voorgestel, wat kenmerkonttrekkingsmetodes, foutidenti kasie en verskillende metodes om betroubaarheidsgrense te beraam saamsnoer. Vir kern-gebaseerde metodes laat die algemene raamwerk toe dat die resultate in die invoerruimte vertolk kan word, in plaas van in die kenmerkruimte. 'n Belangrike stap in prosesmonitering is om veranderlikes te identifiseer wat verantwoordelik is vir foute. Alhoewel alle foute wat by 'n chemiese aanleg kan plaasvind, nie vooraf bekend kan wees nie, is dit moontlik om kennis van vorige foute of simulasies te gebruik om die herhaalde voorkoms van die foute te antisipeer. 'n Raamwerk vir foutdiagnose wat van eenklas-steunvektormasjiene (SVM) gebruik maak is voorgestel. Vergeleke met ander tegnieke wat voorheen bestudeer is, is aangetoon dat die eenklas-SVM benadering oor die algemeen beter robuustheid en prestasiekenmerke het. Meeste metodes vir prosesmonitering maak min gebruik van data wat opgeneem is onder normale bedryfstoestande, alhoewel meeste kwaliteitsprobleme ondervind word waneer die proses onder beheer is. In die laaste bydrae, is 'n metodologie vir die kontinue optimering van prosesprestasie voorgestel, wat steunvektormasjiene en beslissingsbome kombineer. Die metodologie is gebaseer op die kontinue soeke na kwaliteitsverbeteringe deur die normale bedryfstoestandsgrense, soos bepaal deur statistiese beheer, te toets. Gesimuleerde en werklike aanlegdata is gebruik om die benadering te illustreer.
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Traina, J. Adam (Jeffrey Adam). "Diagnosing intensive care units and hyperplane cutting for design of optimal production systems." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/100090.
Повний текст джерелаАнотація:
Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2015. In conjunction with the Leaders for Global Operations Program at MIT.Thesis: M.B.A., Massachusetts Institute of Technology, Sloan School of Management, 2015. In conjunction with the Leaders for Global Operations Program at MIT.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 101-107).
This thesis provides a new framework for understanding how conditions, people, and environments of the Intensive Care Unit (ICU) effect the likelihood the preventable harm will happen to a patient in the ICU. Two years of electronic medical records from seven adult ICUs totalling 77 beds at Beth Israel Deaconess Medical Center (BIDMC) were analysed. Our approach is based on several new ideas. First, instead of measuring safety through frequency measurement of a few relatively rare harms, we leverage electronic databases in the hospital to measure Total Burden of Harm, which is an aggregated measure of a broad range of harms. We believe that this measure better reflects the true level of harm occurring in Intensive Care Units and also provides hope for more statistical power to understand underlying contributors to harm. Second, instead of analysing root causes of specific harms or risk factors of individual patients, we focus on what we call Risk Drivers, which are conditions of the ICU system, people (staff, patients, families) and environments that affect the likelihood of harms to occur, and potentially their outcomes. The underlying premise is that there is a relatively small number of risk drivers which are common to many harms. Moreover, our hope is that the analysis will lead to system level interventions that are not necessarily aiming at a specific harm, but change the quality and safety of the system. Third, using two years of data that includes measurements of harms and drivers values of each shift and each of seven ICUs at BIDMC, we develop an innovative statistical approach that identifies important drivers and High and Low Risky States. Risky States are defined through specific combinations of values of Risk Drivers. They define environmental characteristics of ICUs and shifts that are correlated with higher or lower risk level of harms. To develop a measurable set of Risk Drivers, a survey of current ICU quality metrics was conducted and augmented with the clinical experience of senior critical care providers at BIDMC. A robust machine learning algorithm with a series of validation techniques was developed to determine the importance of and interactions between multiple quality metrics. We believe that the method is adaptable to different hospital environments. Sixteen statistically significant Risky States (p < .02) where identified at BIDMC. The harm rates in the Risky States range over a factor of 10, with high risk states comprising more that 13.9% of the total operational time in the ICU, and low risk states comprise 38% of total operating shifts. The new methodology and validation technique was developed with the goal of providing a basic tools which are adaptable to different hospitals. The algorithm described within serves as the foundation for software under development by Aptima Human Engineering and the VA Hospital network with the goal of validation and implementation in over 150 hospitals. In the second part of this thesis, a new heuristic is developed to facilitate the optimal design of stochastic manufacturing systems. The heuristic converges to optimal, or near optimal results in all test cases in a reasonable length of time. The heuristic allows production system designers to better understand the balance between operating costs, inventory costs, and reliability.
by J Adam Traina.
S.M.
M.B.A.
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Rittenhouse, Scott A. "Diagnosis of operational changes in microelectromechanical systems via fault detection." Morgantown, W. Va. : [West Virginia University Libraries], 2004. https://etd.wvu.edu/etd/controller.jsp?moduleName=documentdata&jsp%5FetdId=3632.
Повний текст джерелаАнотація:
Thesis (M.S.)--West Virginia University, 2004.Title from document title page. Document formatted into pages; contains v, 141 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 137-141).
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Silmon, Joseph A. "Operational industrial fault detection and diagnosis : railway actuator case studies." Thesis, University of Birmingham, 2009. http://etheses.bham.ac.uk//id/eprint/481/.
Повний текст джерелаАнотація:
Modern railways are required to operate with a high level of safety and reliability. The weakest components are those which have the highest safety requirements and the lowest inherent reliability. Single-throw mechanical actuators, such as powered train doors, trainstops, level crossing barriers and switch actuators (point machines) are a group of components which have these properties. Preventative maintenance is carried out periodically in order to mitigate the risks of these actuators failing. This is inefficient: a condition-based maintenance approach would reduce costs and the risks to staff. However, this kind of maintenance requires very accurate automatic condition monitoring. Currently, the threshold-based condition monitoring systems installed in pilot schemes around the country do not have enough insight into actuator performance to detect incipient faults. These are hard to spot because their symptoms develop over a long period of time. It is uneconomical to carry out detailed analysis or modelling, or collect a large amount of training data, for each instance of a large group of assets. Therefore, the solution needed to establish diagnosis rules based on offline analysis, or training data from only one actuator. This thesis draws on previous work in qualitative trend analysis to build a diagnosis system which uses a combined approach of qualitative and quantitative analysis to transfer the knowledge gathered from one actuator to its fellows in service. The method used has been designed to use straightforward components, so that it can be more easily explained to users. Two case studies were carried out in order to verify the system's functions. Data were collected from real-life actuators, under simulation of incipient faults. The diagnosis system then operated on the data. The system's performance was almost as good with real-world data as it was with synthetic data. The system has been a success when operating on the data gathered under laboratory conditions. In the real world, a system such as this could be used to post-process data gathered around the railway network from actuators with local data acquisition equipment. Incipient faults could be detected in the early stages of their development and accurately diagnosed, allowing maintenance effort to be targeted very specifically, saving money, time and exposing staff to fewer hazards.
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Li, Chenlin. "Biohydrogen production under various operational conditions." View the Table of Contents & Abstract, 2006. http://sunzi.lib.hku.hk/hkuto/record/B36995903.
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Carvalho, Rita Isabel Quintas Gouveia de. "Diagnosis of implementation and impact study of operational risk under Basel II." Master's thesis, Instituto Superior de Economia e Gestão, 2007. http://hdl.handle.net/10400.5/763.
Повний текст джерелаАнотація:
Mestrado em FinançasThe purpose of this document is to discuss some of the most controversial aspects of Basel II specifically relating to Operational Risk requirements in terms of Capital adequacy. The author presents an overview of the Basel II framework in terms of foundation, fundamentals and challenges, and specifically operational risk requirements under Pillar I, before going on to discuss some of its most controversial aspects. Against our initial expectations, several interviews conducted with Operational Risk Officers as well as with Risk experts, consolidated by the analysis of databases and international surveys, show evidence to conclude that banks are still quite reluctant and struggling to understand the specific requirements of the Advanced Measurement Approach (AMA). This, together with the Key Risk Indicators component, remains the major challenge to the financial institutions, both still in a very early completion stage. The author also discusses practices and methodologies in terms of operational risk modeling, presenting an alternative development approach for a possible future update of the Basel requirements, as relates to aggregated event type differentiated treatment, for operational risk modeling, and thus capital calculation, in the scope of the soundness criteria defined under AMA, in view of its practical value towards its feasibility and the advantages of a larger implementation of such an approach. The author therefore demands, for the benefit of the overall Financial System, greater adhesion by Banks to more operational risk sensitive approaches, namely AMA. This prepares the ground for a proposal towards the development of a regulatory incentive framework on capital calculation, to be applied within the implementation stage to AMA, to motivate banks to move, and as early as possible, to implementing more risk-sensitive bottom-up operational risk models and management practices.
O objectivo deste trabalho assenta na discussão de alguns dos aspectos mais controversos relacionados com os requisitos de Capital regulatório oriundos do Risco Operacional no âmbito do Acordo de Basileia II. É efectuado um enquadramento do Basileia II e dos maiores desafios específicos para tratamento do Risco Operacional. Foi desenvolvido um trabalho de diagnóstico e pesquisa baseado em entrevistas a Responsáveis de Risco Operacional de Bancos Nacionais, Internacionais e a reputados investigadores internacionais desta área, alicerçado pela análise de algumas bases de dados e de vários questionários efectuados ao nível internacional. Contrariando as expectativas iniciais, muitos Bancos mantêm-se actualmente ainda reluctantes face à implementação de métodos mais avançados (AMA), existindo uma propensão ainda muito significativa pelos métodos menos avançados, i.e. o método Básico ou Standardizado. As maiores dificuldades prendem-se com os requisitos específicos delineados para o método mais avançado (AMA) e com a identificação e tratamento dos Indicadores Chave de Risco (KRI), ainda numa fase muito primária em termos de implementação. É igualmente discutido prácticas e metodologias, em termos de modelos de risco operacional, no âmbito do AMA. O presente trabalho desenvolve a teoria de que é fundamental uma maior adesão dos bancos à implementação do AMA. É, nestes termos, efectuada uma proposta para efeitos de futuros desenvolvimentos alternativos que possibilitem uma adesão mais generalizada à implementação do AMA. A proposta assenta no tratamento diferenciado em termos de modelação específica de risco operacional por segmentos agregados de tipologia de eventos de perda, para cálculo de capital regulatório, e por último, no desenvolvimento e aplicação regulatória de um enquadramento de incentivo, em fase de implementação para o AMA, para motivar os Bancos a promoverem rapidamente a implementação de modelos de gestão de risco operacional mais sofisticados e sensitivos, com as vantagens inerentes para a estabilidade e eficiência de todo o Sistema Financeiro.
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Endo, Fumihiro, Masaki Kanamitsu, Ryo Shiomi, Hiroki Kojima, Naoki Hayakawa, and Hitoshi Okubo. "Optimization of Asset Management and Power System Operation Based on Equipment Performance." IEEE, 2008. http://hdl.handle.net/2237/11798.
Повний текст джерела
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Li, Chenlin, and 李晨林. "Biohydrogen production under various operational conditions." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2006. http://hub.hku.hk/bib/B37437549.
Повний текст джерела
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Cairncross, Lydia Leone. "Pre-operative diagnosis of thyroid cancer : clinical, radiological and pathological correlation." Master's thesis, University of Cape Town, 2011. http://hdl.handle.net/11427/10230.
Повний текст джерелаАнотація:
Primary Aim: assess the accuracy of pre operative diagnosis of thyroid cancer in a single centre. Secondary Aims: evaluate the impact of preoperative diagnosis on surgical interventions for thyroid carcinoma; develop locally applicable guidelines for patients with nodular disease of the thyroid.
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Burton, Sarah L. "Logistic regression models and their application in medical discrimination and diagnosis." Thesis, University of Sheffield, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.364332.
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Keller, Julia Henriette [Verfasser]. "Diagnosing the Downstream Impact of Extratropical Transition Using Multimodel Operational Ensemble Prediction Systems / Julia Henriette Keller." Karlsruhe : KIT Scientific Publishing, 2013. http://www.ksp.kit.edu.
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Rezayi, Shahin. "Kvinnors upplevelser tiden efter att de fått diagnosen bröstcancer fram till operation : En litteraturstudie av patografier." Thesis, Blekinge Tekniska Högskola, Institutionen för hälsa, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-12001.
Повний текст джерела
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Feng, Ming-Fa. "Fault diagnosis and prediction in reciprocating air compressors by quantifying operating parameters." Diss., Virginia Tech, 1992. http://hdl.handle.net/10919/39786.
Повний текст джерелаАнотація:
This research introduces a new method of diagnosing the internal condition of a reciprocating air compressor. Using only measured load torques and shaft dynamics, pressures, temperatures, flow rates, leakages, and heat transfer conditions are quantified to within 5%.
The load torque acting on the rotor of the machine is shown to be a function of the dynamics (instantaneous position, velocity, and acceleration) of the driving shaft, the kinematic construction, and the internal condition of the machine. If the load torque, the kinematic construction of the machine, and the dynamics of the rotor are known, then the condition of the machine can be assessed.
A theoretical model is developed to describe the physical behavior of the slider-crank mechanism and the shaft system. Solution techniques, which are based on the machine construction, crankshaft dynamics, and load torque measurements, are presented to determine the machine parameters. A personal computer based system used to measure the quantities necessary to solve for the machine parameters and the quantities used to compare with calculations is also documented.
The solution algorithm for multi-stage compressors is verified by decoupling the load torque contributed by each cylinder. Pressure data for a four-stage two-cylinder high pressure air compressor (HPAC) is used. Also, the mathematical model is proven feasible by using measured angular velocity of the crankshaft and direct measurements of the load torque of a single stage, single cylinder air compressor to solve for the machine parameters.
With this unintrusive and nondestructive method of quantifying the operating parameters, the cylinder pressures, operating temperatures, heat transfer conditions, leakage, and power consumption of a reciprocating air compressor can be evaluated.Ph. D.
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Tennant, William G. "The pathogenesis and pre-operative diagnosis of inflammatory aneurysms of the aorta." Thesis, University of Edinburgh, 1993. http://hdl.handle.net/1842/20829.
Повний текст джерелаАнотація:
Inflammatory abdominal aortic aneurysms constitute approximately 15% of all abdominal aortic aneurysms. Macroscopically, they are characterised by a thick white rind of fibrous tissue, which may extend to the retroperitoneum to encase and obstruct adjacent hollow organs. This may require major changes and modifications in exposure and operative technique. Currently, diagnostic accuracy is poor in inflammatory aortic aneurysm disease, and little is known of its pathogenesis. This leads to many such aneurysms remaining unsuspected pre-operatively, and contributes to the increased operative morbidity and mortality of this disease. A review of the history of vascular surgery and radiology is undertaken, with a particular emphasis on aneurysm disease. Current theories of the aetiology of both simple and inflammatory aneurysm are discussed. An account is given of the current state of radiological techniques in the diagnosis of inflammatory aneurysm disease, and a brief technical synopsis of magnetic resonance imaging (MRI) is provided. A retrospective series was studied, comprising 47 patients with IA and 162 patients with SA of matched age and sex distribution. No differences were found in the incidence of diabetes, smoking, symptomatic occlusive vascular disease or hypertension. Pain was slightly more common in the IA group, but weight loss was not. Plasma viscosity was the only measured haematological parameter which differed significantly between the groups, being higher in the IA group compared to the other two. Biochemical evidence of renal failure was a poor predictor of ureteric involvement in fibrosis. Post-operative ultrasound failed to make the diagnosis of IA in all cases subsequently confirmed at operation. Computerised tomography (CT) made the diagnosis in only 13 of 25 cases. All aortic replacements were carried out using the transperitoneal route. In 4 cases of IA however, unexpectedly extensive abdominal inflammatory change required the abdominal incision to be extended as a left eighth rib thoracotomy. 63% of patients with IA required bifurcation grafts rather than tube grafts, the figures being almost exactly reversed for patients with SA.
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Sae-Kok, Warachart. "Converter fault diagnosis and post-fault operation of a doubly-fed induction generator for a wind turbine." Thesis, University of Strathclyde, 2008. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=21980.
Повний текст джерелаАнотація:
Wind energy has become one of the most important alternative energy resources because of the global warming crisis. Wind turbines are often erected off-shore because of favourable wind conditions, requiring lower towers than on-shore. The doubly-fed induction generator is one of the most widely used generators with wind turbines. In such a wind turbine the power converters are less robust than the generator and other mechanical parts. If any switch failure occurs in the converters, the wind turbine may be seriously damaged and have to stop. Therefore, converter health monitoring and fault diagnosis are important to improve system reliability. Moreover, to avoid shutting down the wind turbine, converter fault diagnosis may permit a change in control strategy and/or reconfigure the power converters to permit post-fault operation. This research focuses on switch fault diagnosis and post-fault operation for the converters of the doubly-fed induction generator. The effects of an open-switch fault and a short-circuit switch fault are analysed. Several existing open-switch fault diagnosis methods are examined but are found to be unsuitable for the doubly-fed induction generator. The causes of false alarms with these methods are investigated. A proposed diagnosis method, with false alarm suppression, has the fault detection capability equivalent to the best of the existing methods, but improves system reliability. After any open-switch fault is detected, reconfiguration to a four-switch topology is activated to avoid shutting down the system. Short-circuit switch faults are also investigated. Possible methods to deal with this fault are discussed and demonstrated in simulation. Operating the doubly-fed induction generator as a squirrel cage generator with aerodynamic power control of turbine blades is suggested if this fault occurs in the machine-side converter, while constant dc voltage control is suitable for a short-circuit switch fault in the grid-side converter.
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Bai, Hao. "A generic fault detection and diagnosis approach for pneumatic and electric driven railway assets." Thesis, University of Birmingham, 2010. http://etheses.bham.ac.uk//id/eprint/1202/.
Повний текст джерелаАнотація:
The railway assets studied in this project, are those widely distributed pieces of equipment that are critical to the dependable operation of the railway system. A failed asset is likely to cause significant delay to rail services, and may even place the system into an unsafe state. A generic fault detection and diagnosis (FDD) solution for a number of railway assets of different types is therefore desired. In this thesis, five assets, namely the pneumatic train door, point machine and train-stop, the electric point machine and the electro-hydraulic level crossing barrier, are considered as case studies. Based on their common dynamic characteristics, these assets are also known as Single Throw Mechanical Equipments (STMEs). A generic FDD method is proposed for these STMEs, which consists of sensor inputs and pre-processing, fault detection processes and fault diagnosis processes. A generic model, composed of a series of sub-models, is constructed to describe the behaviour of each asset. The results of fault detection approaches indicate that the proposed method has good performance and is generically applicable to the five assets. Two fault diagnosis methods using fault model and residual analysis are proposed and the fault model based fault diagnosis is preliminarily approached. Finally, a new three level architecture for railway condition monitoring is discussed for practical applications.
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Okubo, Hitoshi, Fumihiro Endo, Naoki Hayakawa, Hiroki Kojima, and Yotaro Suzuki. "Optimization of Asset Management in High Voltage Substation Based on Equipment Monitoring and Power System Operation." IEEE, 2010. http://hdl.handle.net/2237/14536.
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Yamamoto, Ayako. "Validation of new operational package for the Lagrangian diagnosis of stratosphere-troposphere exchange." Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=106407.
Повний текст джерелаАнотація:
A new tool for the Lagrangian diagnosis of stratosphere-troposphere exchange (STE) was developed for Environment Canada and became operational in July 2010, providing unique, high-resolution daily forecasts of STE over the globe. This thesis offers a comprehensive validation of these STE forecasts in the context of an ozonesonde balloon campaign conducted at three locations in Eastern Canada from 12 July to 4 August 2010. The STE forecasts are calculated using a Lagrangian kinematic trajectory methodology based on the high-resolution global GEM model forecasts at Environment Canada. Both observations and the STE forecasts during this period showed much larger frequency of stratospheric air intrusions deep into the troposphere at all locations compared to past studies. The STE dataset compares reasonably well with the observations above 500 hPa, yet is found to underestimate the frequency of events reaching below 700 hPa level. Sources of error can possibly be introduced by (1) errors in the 6-day global GEM forecasts, (2) errors in the identification of air with stratospheric origin in observations, and/or (3) the lack of convective and turbulent mixing representation in the trajectory model. Despite these large sources of errors, the STE forecasts turn out to be one of the best datasets available for the STE studies, being useful to estimate the currently controversial STE contribution to the tropospheric ozone budget in the free troposphere as well as in the boundary layer.Un nouvel outil de diagnostic d'échange stratosphère-troposphère (STE) a été développé pour Environment Canada et est devenu opérationnel en Juillet 2010, fournissant des prévisions quotidiennes de haute résolution à l'échelle globale. Cette thèse offre une validation complète des prévisions STE dans le contexte d'une campagne de ballons-sondes mesurant l'ozone, conduite à trois localisations dans l'Est du Canada du 12 Juillet au 4 Août 2010. Les prévisions STE sont calculées avec une méthode cinématique de trajectoires Lagrangiennes basée sur la sortie du modèle global à haute résolution GEM d'Environment Canada. Les observations et résultats du modèle montrent une fréquence d'intrusions profondes d'air stratosphérique bien plus grande que dans les études précédentes. Les données STE correspondent relativement bien aux observations au dessus de 500 hPa, mais elles sous-estiment la fréquence des évènements attaignant 700 hPa. Les sources d'erreurs sont possiblement: (1) des erreurs dans la prévision de GEM, (2) des erreurs dans l'identification de parcelle d'air d'origine stratosphérique et/ou (3) le manque de convection et de turbulence dans le modèle de trajectoire. Malgré ces sources d'erreurs, les données d'intrusions s'avèrent être une des meilleures sources disponible pour, entre autres, estimer la présente et controversée contribution stratosphérique au budget total d'ozone de la troposphère.
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Nagala, Sidhartha. "Correlating thyroid tumour pathology with magnetic resonance biomarkers to improve pre-operative diagnosis." Thesis, University of Cambridge, 2014. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.708232.
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Albusaidi, Waleed. "Techno-economic assessment of radial turbomachinery in process gas applications." Thesis, Cranfield University, 2016. http://dspace.lib.cranfield.ac.uk/handle/1826/9872.
Повний текст джерелаАнотація:
This research aims to assess the causes of inefficient and unstable operation of centrifugal compressors and turboexpanders in process gas applications in order to provide a solution for performance restoration and enhancement. It encompasses thermodynamic and flow evaluations to examine the efficiency and operating range improvement options of new units. Besides, this work is complemented by a technoeconomic analysis to provide a rounded outcome from these studies. In order to achieve the desired objectives, a novel integrated approach has been developed to assess the design and performance of multi-stage centrifugal compressors. The proposed systematic methodology involves five basic elements including evaluation of compressor selection, compressor sizing and casing structure, performance prediction at the design and off-design conditions, modelling of efficiency and head deterioration causes; and stage design evaluation. This will contribute towards evaluating the geometrical parameters of the new units’ designs at the early preliminary design phase, and thus, will be useful to identify the options for efficiency and operating range enhancements. For installed units, this approach can be implemented to assess the cause of inefficient and unstable operation by assessing the available operation data. A method was developed to predict the performance curve of multi-stage centrifugal compressor based on a stage stacking technique. This approach considers the advantages of Lüdtke and Casey-Robinson methods with an incorporation of a methodology for compressor selection and sizing to generate more accurate results. To emphasize the validity of the developed model, it has been evaluated for both low and high flow coefficient applications. The obtained results show a significant improvement in the estimated efficiency, pressure ratio, shaft power and operating range as compared with the existing methods. The centrifugal compressor is designed to run under various operating conditions and different gas compositions with the primary objective of high efficiency and reliability. Therefore, a new iterative method has been developed to predict the equivalent compressor performance at off-design conditions. This technique uses the performance parameters at design conditions as a reference point to derive the corresponding performance characteristics at numerous suction conditions with less dependency on the geometrical features. Through a case study on a gas transport centrifugal compressor, it was found that the developed approach can be applied for design evaluation on the expected variation of working conditions, and for the operation diagnosis of installed units as well. Furthermore, a parametric study has been conducted to investigate the effect of gas properties on the stage efficiency, surge margin, and compressor structure. The obtained results support the need for considering the gas properties variation when the off-design performance is derived. To evaluate the impact of internal blockage on the performance parameters, this study proposed an approach to model the effect of non-reactive deposits, which has been qualified using four operation cases and the obtained results are compared with the internal inspection findings from the stage overhauling process. This also covers the influential aspects of flow blockage on the technical and economic values. Since the main challenge here is to analyze the process gas composition in real time, the influences of the non-reactive deposits have been compared with the effect of the unanticipated gas composition change. Subsequently, it has turned out that the pressureratio parameter is not enough to assess the possibility of flow blockage and unexpected gas properties change. Moreover, it was observed that the stage discharge pressure was more sensitive to the fouled aftercooler comparing with suction and internal blockage. However, the effect of contaminated aftercooler on the surge point and discharge pressure and temperature of the upstream stage was found greater than its impact on the shaft power. Thus, a substantial surge margin reduction was detected when the first stage was operating with a fouled aftercooler comparing with the measured reduction as a result of unanticipated gas properties change. Furthermore, a larger pressure ratio drop was measured in the case of liquid carryover which revealed a more significant impact of the two phases densities difference comparing with the gas volume fraction (GVF) effect. The possibility of hydrate formation has been assessed using hydrate formation temperature (HFT) criteria. Additionally, this research highlights a number of challenges facing the selection of typical centrifugal stage design by assessing the contribution of design characteristics on the operating efficiency and stable flow range. Besides, an empirical-based-model was established to select the optimum impeller and diffuser configurations in order to make a compromise decision based on technical and economic perspective. It was concluded that there is no absolute answer to the question of optimum rotor and stator configuration. The preliminary aerothermodynamic evaluation exposed that the selection of the optimum impeller structure is governed by several variables: stage efficiency, pressure loss coefficient, manufacturing cost, required power cost, resonance frequency and stable operating range. Hence, an evaluation is required to compromise between these parameters to ensure better performance. Furthermore, it was argued throughout this study that the decision-making process of the typical stage geometrical features has to be based upon the long-term economic performance optimization. Thus, for higher long-term economic performance, it is not sufficient to select the characteristics of the impeller and diffuser geometry based on the low manufacturing cost or efficiency improvement criterion only. For turboexpanders, a simple and low cost tool has been developed to determine the optimum turboexpander characteristics by analysing the generated design alternatives. This approach was used in designing a turboexpander for hydrocarbon liquefaction process. Moreover, since the turboexpanders are expected to run continuously at severe gas conditions, the performance of the selected turboexpander was evaluated at different inlet flow rates and gas temperatures. It has turned out that designing a turboexpander with the maximum isentropic efficiency is not always possible due to the limitations of the aerodynamic parameters for each component. Therefore, it is necessary to assess the stage geometrical features prior the construction process to compromise between the high capital cost and the high energetic efficiency.
31
Carrel, André S. M. Massachusetts Institute of Technology. "Diagnosis and assessment of operations control interventions : framework and applications to a high frequency metro line." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/55152.
Повний текст джерелаАнотація:
Thesis (S.M. in Transportation)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2009.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 178-180).
Service control, the task of implementing the timetable in daily operations on a metro line, plays a key role in service delivery, as it determines the quality of the service as provided to passengers. This thesis proposes a framework for the study of rail service control which builds on the integration and analysis of data from multiple sources and on background knowledge about service control. The framework takes into account the decision environment in which service control takes place and acknowledges that the reliability of the system depends on many factors which are endogenous to it, aspects previously not recognized in a comprehensive manner by researchers and practitioners alike. This research makes use of automatically generated operational and passenger data, which are increasingly available and accessible to transit agencies and allow for addressing questions in service control from multiple perspectives. As a result, this study takes a distinctly different approach than previous research, which has mostly focused on individual service control strategies and relied heavily on modeling and on simplifying assumptions about the objectives and constraints of service control on a metro line. The developed framework consists of four main elements. First, the controller's decision environment is integrated and described based on an extended visit of the author to a control center. Second, an algorithm for reconstructing train operations from signaling data and identifying service control interventions is presented. Third, a measure for assessing the impact of the interventions on operations is introduced.
(cont.) The fourth and final element is a set of passenger travel time and reliability measures. The framework is applied to the Central line, a high-frequency line of the London Underground where the control center observations were also made. Three common service control strategies are assessed in terms of their impact on operations and on passengers, and the influence of timetable variables on the frequency of service control interventions is investigated. From observations at the control center, it is found that aside from the objective of maintaining adequate levels of service from an operations perspective and minimizing the impact of schedule deviations on passengers, considerations relating to crew and rolling stock management, safety and infrastructure capacity have a major influence on service control decisions. Given the uncertain environment in which service control operates, a strong preference among controllers for manageable and robust solutions is observed. In the analysis of common control strategies, it is found that in the absence of official policies on the response to certain types of problems on the line and in the presence of the multitude of factors mentioned above, service controllers have developed rules of thumb which may not always be optimal from the passengers' perspective. Furthermore, the fundamental tradeoff is highlighted between the availability of spare resources in form of drivers, trains and infrastructure capacity and the need for service control interventions.
(cont.) Regarding the influence of timetable variables, it is found that an increase in scheduled service frequency and in running times on an otherwise unchanged line operating close to its capacity caused significant increases in numbers of service control interventions, mostly due to a higher rolling stock requirement and reduced operational flexibility. Recommendations are made with regards to service control policies, the structure of responsibilities among operational staff, the design of the timetable and the design of the operations control system. Although the results provided by the applications are specific to the Central line, they demonstrate how the elements of the framework can be implemented in a practical setting, and many of the conclusions of this thesis are transferable to other metro lines and systems. Finally, future research in passenger behavior and crew management in the presence of service control interventions is proposed.
by André Carrel.
S.M.in Transportation
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Tembey, Mugdha. "Computer-Aided Diagnosis for Mammographic Microcalcification Clusters." [Tampa, Fla.] : University of South Florida, 2003. http://purl.fcla.edu/fcla/etd/SFE0000168.
Повний текст джерела
33
Poulon, Fanny. "Tissue database of autofluorescence response to improve intra-operative diagnosis of primitive brain tumors." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS236/document.
Повний текст джерелаАнотація:
Le premier traitement standard pour les tumeurs cérébrales est la résection chirurgicale. Dans cette procédure un enjeu important demeure, l'identification des berges tumorales pour assurer une résection totale et éviter le risque de récidive pour le patient. A ce jour aucune technique d'imagerie peropératoire est capable de résoudre l'infiltration tumorale du tissu sain. La norme pour le diagnostic des berges tumorales est l'analyse histologique des biopsies. Une méthode ex vivo qui requiert un à plusieurs jours pour fournir ler apport pathologique final, un lapse de temps qui peut s'avérer fatal pour le patient. La microscopie optique a récemment été développer vers une utilisation clinique peropératoire pour répondre à cet enjeu. Dans travail, la technique de microscopie à deux-photons a été préférée pouressayer de répondre à cette problématique. Cette méthode donne accès à deux contrastes d'imagerie, la génération de seconde harmonique et l’émission de fluorescence, qui peuvent être combinés à des mesures quantitatives, tel que la spectroscopie et le temps de vie de fluorescence. Combiner ces quatre modalités de détection donnera une information complète sur la structure et le métabolisme de la région observée. Pour soutenir le développement technique vers une sonde endomicroscopique visant une utilisation peropératoire, les données en résultants doivent être fiables, et se montrer d'un intérêt pour le chirurgien. Par conséquent, une base de données sur le signal d'autofluorescence des tissus a été construite et présentée dans ce manuscrit, avec des algorithmes capables de discriminer de façon fiable les régions tumorales des régions saines. Des algorithmes qui ont montré le potentiel d'être automatisé dans une configuration clinique, afin de fournir une réponse en temps-réel au chirurgienThe first standard approach for brain tumor treatment is the surgical resection. In this protocol an important challenge remains, the identification of tumor margins to ensure a complete resection and avoid risk of tumor recurrence. Nowadays no intra-operative means of contrast are able to resolve infiltrated regions from healthy tissue. The standard for tumor margin diagnosis is the histological analysis of biopsies. An ex vivo method that requires one to several days to issue a final pathological reports, a time lapse that could be fatal to the patient. Optical microscopy have recently been developed towards an intra-operative clinical use to answer this challenge. In this work, the technique of two-photon microscopy based on the autofluorescence of tissue have been favored. This technique gives access to two imaging contrasts, the second-harmonic generation and emission of fluorescence, and can be combined to quantitative measurements, such as spectroscopy and fluorescence lifetime. The combination of these four modalities of detection will give a complete structural and metabolic information on the observed region. To support the technical development towards an endomicroscopic probe, the resulted data have to be reliable and proved to be of interest for the surgeon. Consequently, an extensive database of the autofluorescence response of brain tumor tissue have been constructed and presented in this manuscript, with algorithms able to discriminate with reliability tumoral from healthy regions. Algorithms that have shown potential to be automatized in a clinical setting, in order to give a real-time answer to the surgeons
34
Keller, Julia Henriette [Verfasser], and S. [Akademischer Betreuer] Jones. "Diagnosing the Downstream Impact of Extratropical Transition Using Multimodel Operational Ensemble Prediction Systems / Julia Henriette Keller. Betreuer: S. Jones." Karlsruhe : KIT-Bibliothek, 2012. http://d-nb.info/1020230037/34.
Повний текст джерела
35
Sarikhani, Ali. "Design Optimization of Modern Machine-drive Systems for Maximum Fault Tolerant and Optimal Operation." FIU Digital Commons, 2012. http://digitalcommons.fiu.edu/etd/766.
Повний текст джерелаАнотація:
Modern electric machine drives, particularly three phase permanent magnet machine drive systems represent an indispensable part of high power density products. Such products include; hybrid electric vehicles, large propulsion systems, and automation products. Reliability and cost of these products are directly related to the reliability and cost of these systems. The compatibility of the electric machine and its drive system for optimal cost and operation has been a large challenge in industrial applications. The main objective of this dissertation is to find a design and control scheme for the best compromise between the reliability and optimality of the electric machine-drive system. The effort presented here is motivated by the need to find new techniques to connect the design and control of electric machines and drive systems.
A highly accurate and computationally efficient modeling process was developed to monitor the magnetic, thermal, and electrical aspects of the electric machine in its operational environments. The modeling process was also utilized in the design process in form finite element based optimization process. It was also used in hardware in the loop finite element based optimization process. The modeling process was later employed in the design of a very accurate and highly efficient physics-based customized observers that are required for the fault diagnosis as well the sensorless rotor position estimation. Two test setups with different ratings and topologies were numerically and experimentally tested to verify the effectiveness of the proposed techniques.
The modeling process was also employed in the real-time demagnetization control of the machine. Various real-time scenarios were successfully verified. It was shown that this process gives the potential to optimally redefine the assumptions in sizing the permanent magnets of the machine and DC bus voltage of the drive for the worst operating conditions.
The mathematical development and stability criteria of the physics-based modeling of the machine, design optimization, and the physics-based fault diagnosis and the physics-based sensorless technique are described in detail.
To investigate the performance of the developed design test-bed, software and hardware setups were constructed first. Several topologies of the permanent magnet machine were optimized inside the optimization test-bed. To investigate the performance of the developed sensorless control, a test-bed including a 0.25 (kW) surface mounted permanent magnet synchronous machine example was created. The verification of the proposed technique in a range from medium to very low speed, effectively show the intelligent design capability of the proposed system. Additionally, to investigate the performance of the developed fault diagnosis system, a test-bed including a 0.8 (kW) surface mounted permanent magnet synchronous machine example with trapezoidal back electromotive force was created. The results verify the use of the proposed technique under dynamic eccentricity, DC bus voltage variations, and harmonic loading condition make the system an ideal case for propulsion systems.
36
Vidal, Puig Santiago. "FAULT DIAGNOSIS TOOLS IN MULTIVARIATE STATISTICAL PROCESS AND QUALITY CONTROL." Doctoral thesis, Universitat Politècnica de València, 2016. http://hdl.handle.net/10251/61292.
Повний текст джерелаАнотація:
[EN] An accurate fault diagnosis of both, faults sensors and real process faults have become more and more important for process monitoring (minimize downtime, increase safety of plant operation and reduce the manufacturing cost). Quick and correct fault diagnosis is required in order to put back on track our processes or products before safety or quality can be compromised. In the study and comparison of the fault diagnosis methodologies, this thesis distinguishes between two different scenarios, methods for multivariate statistical quality control (MSQC) and methods for latent-based multivariate statistical process control: (Lb-MSPC). In the first part of the thesis the state of the art on fault diagnosis and identification (FDI) is introduced. The second part of the thesis is devoted to the fault diagnosis in multivariate statistical quality control (MSQC). The rationale of the most extended methods for fault diagnosis in supervised scenarios, the requirements for their implementation, their strong points and their drawbacks and relationships are discussed. The performance of the methods is compared using different performance indices in two different process data sets and simulations. New variants and methods to improve the diagnosis performance in MSQC are also proposed. The third part of the thesis is devoted to the fault diagnosis in latent-based multivariate statistical process control (Lb-MSPC). The rationale of the most extended methods for fault diagnosis in supervised Lb-MSPC is described and one of our proposals, the Fingerprints contribution plots (FCP) is introduced. Finally the thesis presents and compare the performance results of these diagnosis methods in Lb-MSPC. The diagnosis results in two process data sets are compared using a new strategy based in the use of the overall sensitivity and specificity[ES] La realización de un diagnóstico preciso de los fallos, tanto si se trata de fallos de sensores como si se trata de fallos de procesos, ha llegado a ser algo de vital importancia en la monitorización de procesos (reduce las paradas de planta, incrementa la seguridad de la operación en planta y reduce los costes de producción). Se requieren diagnósticos rápidos y correctos si se quiere poder recuperar los procesos o productos antes de que la seguridad o la calidad de los mismos se pueda ver comprometida. En el estudio de las diferentes metodologías para el diagnóstico de fallos esta tesis distingue dos escenarios diferentes, métodos para el control de estadístico multivariante de la calidad (MSQC) y métodos para el control estadístico de procesos basados en el uso de variables latentes (Lb-MSPC). En la primera parte de esta tesis se introduce el estado del arte sobre el diagnóstico e identificación de fallos (FDI). La segunda parte de la tesis está centrada en el estudio del diagnóstico de fallos en control estadístico multivariante de la calidad. Se describen los fundamentos de los métodos más extendidos para el diagnóstico en escenarios supervisados, sus requerimientos para su implementación sus puntos fuertes y débiles y sus posibles relaciones. Los resultados de diagnóstico de los métodos es comparado usando diferentes índices sobre los datos procedentes de dos procesos reales y de diferentes simulaciones. En la tesis se proponen nuevas variantes que tratan de mejorar los resultados obtenidos en MSQC. La tercera parte de la tesis está dedicada al diagnóstico de fallos en control estadístico multivariante de procesos basados en el uso de modelos de variables latentes (Lb-MSPC). Se describe los fundamentos de los métodos mas extendidos en el diagnóstico de fallos en Lb-MSPC supervisado y se introduce una de nuestras propuestas, el fingerprint contribution plot (FCP). Finalmente la tesis presenta y compara los resultados de diagnóstico de los métodos propuestos en Lb-MSPC. Los resultados son comparados sobre los datos de dos procesos usando una nueva estrategia basada en el uso de la sensitividad y especificidad promedia.
[CAT] La realització d'un diagnòstic precís de les fallades, tant si es tracta de fallades de sensors com si es tracta de fallades de processos, ha arribat a ser de vital importància en la monitorització de processos (reduïx les parades de planta, incrementa la seguretat de l'operació en planta i reduïx els costos de producció) . Es requerixen diagnòstics ràpids i correctes si es vol poder recuperar els processos o productes abans de que la seguretat o la qualitat dels mateixos es puga veure compromesa. En l'estudi de les diferents metodologies per al diagnòstic de fallades esta tesi distingix dos escenaris diferents, mètodes per al control estadístic multivariant de la qualitat (MSQC) i l mètodes per al control estadístic de processos basats en l'ús de variables latents (Lb-MSPC). En la primera part d'esta tesi s'introduïx l'estat de l'art sobre el diagnòstic i identificació de fallades (FDI). La segona part de la tesi està centrada en l'estudi del diagnòstic de fallades en control estadístic multivariant de la qualitat. Es descriuen els fonaments dels mètodes més estesos per al diagnòstic en escenaris supervisats, els seus requeriments per a la seua implementació els seus punts forts i febles i les seues possibles relacions. Els resultats de diagnòstic dels mètodes és comparat utilitzant diferents índexs sobre les dades procedents de dos processos reals i de diferents simulacions. En la tesi es proposen noves variants que tracten de millorar els resultats obtinguts en MSQC. La tercera part de la tesi està dedicada al diagnòstic de fallades en control estadístic multivariant de processos basat en l'ús de models de variables latents (Lb-MSPC). Es descriu els fonaments dels mètodes més estesos en el diagnòstic de fallades en MSPC supervisat i s'introdueix una nova proposta, el fingerprint contribution plot (FCP). Finalment la tesi presenta i compara els resultats de diagnòstic dels mètodes proposats en MSPC. Els resultats són comparats sobre les dades de dos processos utilitzant una nova estratègia basada en l'ús de la sensibilitat i especificitat mitjana.
Vidal Puig, S. (2016). FAULT DIAGNOSIS TOOLS IN MULTIVARIATE STATISTICAL PROCESS AND QUALITY CONTROL [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/61292
TESIS
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Andersson, Daniel, and Patrik Sköld. "Evaluation of a diagnostic tool for use during system development and operations." Thesis, Linköping University, Department of Electrical Engineering, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-9567.
Повний текст джерелаАнотація:
Rodon is a diagnostic tool developed by Sörman. SAAB’s interest in Rodon regards the possibility to use the tool for development and operations of aircraft systems. The main goal of this thesis was to evaluate the capacity of Rodon and determine how SAAB can use the diagnostic tool during development and operations.
The tool uses model based diagnosis with artificial intelligence for fault isolation which is a powerful approach. If Rodon is introduced at SAAB, then detailed models of systems will be necessary to create, including the nominal behavior of the system and different faulty behaviors. In order to achieve high quality fault isolation, it is necessary to have complete and consistent models. To be able to use all applications that Rodon feature for a modeled system, preferable characteristics are that the model should be static, have discrete control signals, and have well defined system behavioral modes.
During development of a system Rodon can be used to improve and easy the work for failure analysis, guidance of sensor placements, evaluation of tests, generation of decision structures, and fault isolation. Since design of tests during development is a desirable application that Rodon does not have, two different methods are presented that utilizes Rodon to generate all possible limit checking tests.
In conclusion, Rodon can be very useful in several different aspects if introduced, but benefits gained by using Rodon will have to be compared to the labor cost of creating good models.
38
Malavasi, Laís de Matos. "Physiological and behavioral effects of opioids in pigs subjected to abdominal surgery /." Uppsala : Dept. of Clinical Sciences, Swedish University of Agricultural Sciences, 2005. http://epsilon.slu.se/200580.pdf.
Повний текст джерела
39
Haka, Abigail S. "Development of in vivo Raman spectroscopy for the diagnosis of breast cancer and intra-operative margin assessment." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/30270.
Повний текст джерелаАнотація:
Thesis (Ph. D.)--Harvard University--MIT Division of Health Sciences and Technology, 2005.Includes bibliographical references.
Breast cancer is the most commonly diagnosed cancer among women in the United States. It is the most common cause of death in women ages 45-55. Optical techniques can potentially play a diagnostic role in several aspects of breast cancer evaluation and treatment. This thesis outlines progress on the use of Raman spectroscopy to diagnose breast cancer. Laboratory studies on fresh-frozen tissues are used to demonstrate that the detailed information provided by Raman spectroscopy yields accurate breast disease diagnosis. A Raman spectroscopic-based diagnostic algorithm was developed which classifies samples into four categories according to specific pathological diagnoses: normal, fibrocystic change, fibroadenoma, and infiltrating carcinoma. Cancerous lesions were separated from non- cancerous tissues with a sensitivity of 94% and a specificity of 95%. Further, use of a spectral model based on the morphological structures that comprise breast tissue allows increased understanding of the relationship between a Raman spectrum and tissue disease state. Based on the excellent results of our laboratory work, two clinical studies were undertaken. These studies translate Raman spectroscopy from a laboratory technique into a clinically useful tool. The first study tests the diagnostic algorithm in a prospective manner on freshly excised tissue. Preliminary results are promising. The second study is the first demonstration of in vivo data acquisition of Raman spectra of breast tissue. The culmination of this research is the demonstration of accurate intra-operative margin status assessment during partial mastectomy surgeries.
(cont.) Application of our previously developed diagnostic algorithm resulted in perfect sensitivity and specificity in this small in vivo data set. These preliminary findings indicate that Raman spectroscopy has the potential to lessen the need for re-excision surgeries resulting from positive margins and thereby reduce the recurrence rate of breast cancer following partial mastectomy surgeries. The experiments and theory presented throughout this thesis demonstrate that Raman spectroscopy is a viable clinical tool that can be used to accurately diagnosis breast cancer and breast disease.
by Abigail Susan Haka.
Ph.D.
40
Gao, Jingkun. "A Metadata Inference Framework to Provide Operational Information Support for Fault Detection and Diagnosis Applications in Secondary HVAC Systems." Research Showcase @ CMU, 2017. http://repository.cmu.edu/dissertations/1104.
Повний текст джерелаАнотація:
As the cost of hardware decreases and software technology advances, building automation systems (BAS) have been widely deployed to new buildings or as part of the retrofit to replace the old control systems. Though they are becoming more prevalent and promise important benefits to the society, such as improved energy-efficiency and occupants’ comfort, many of their benefits remain unreachable. Research suggests that this is because of the heterogeneous, fragmented and nonstandardized nature of existing BASs. One of the purported benefits of these systems is the ability to reduce energy consumption through the application of automated approaches such as fault detection and diagnosis (FDD) algorithms. Savings of up to 0.16 quadrillion BTUs per year could be obtained in the US alone through the use of these approaches, which are just software applications running on BAS hardware. However, deployment of these applications for buildings remains a challenge due to the non-trivial efforts of organizing, managing and extracting metadata associated with sensors (e.g., information about their type, function, etc.), which is required by them. One of the reasons leading to the problem is that varying conventions, acronyms, and standards are used to define this metadata. Though standards and governmentmandated policies may lift these obstacles and enable these softwarebased improvements to our building stock, this effort could take years to come to fruition and there are alternative technical solutions, such as automated metadata inference techniques, that could help reign in on the non-standardized nature of today’s BASs. This thesis sheds light on the visibility of this alternative approach by answering three key questions, which are then validated using data from more than 400 buildings in the US: (a) What is the specific operational information required by FDD approaches for secondary heating, ventilation, and air conditioning (HVAC) systems found in existing literature? (b) How is the performance of existing metadata inference approaches affected by changes in building characteristics, weather conditions, building usage patterns, and geographical locations? (c) What is an approach that can provide physical interpretations in the case of incorrect metadata being inferred? We find that: (a) The BAS points required by more than 30% of FDD approaches include six sensors in AHUs monitoring supply air temperature, outside air temperature, chilled water valve position, return air temperature, supply air flow rate, and mixed air temperature; (b) The average performance of existing inference approaches in terms of accuracy is similar across building sites, though there is significant variance, and the expected accuracy of classifying the type of points required by a particular FDD application for a new unseen building is, on average, 75%; (c) A new approach based on physical models is developed and validated on both the simulation data and the real-world data to infer the point types confused by data-driven models with an accuracy ranging from 73% to 100%, and this approach can provide physical interpretations in the case of incorrect inference. Our results provide a foundation and starting point to infer the metadata required by FDD approaches and minimize the implementation cost of deploying FDD applications on multiple buildings.
41
Шавкун, Вячеслав Михайлович, та Viacheslav M. Shavkun. "Підвищення експлуатаційної надійності тягових електричних двигунів тролейбусів". Thesis, Харківський національний університет міського господарства імені О. М. Бекетова, 2014. http://eadnurt.diit.edu.ua/jspui/handle/123456789/2711.
Повний текст джерелаАнотація:
Шавкун, В. М. Підвищення експлуатаційної надійності тягових електричних двигунів тролейбусів: авт. дис. к. т. н.: 05.22.09 / В. М. Шавкун ; Дніпропетр. нац. ун-т залізн. трансп. ім. акад. В. Лазаряна. - Д., 2014. - 20 с. : іл., табл. - Бібліогр.: с. 15-17
ГРНТИ 73.49.23 УДК 629.349-027.45(043.3)
Захист - 23 жовтня 2014 р.UK: АНОТАЦІЯ Дисертаційна робота присвячена вирішенню актуальної наукової задачі – підвищення надійності тягових електричних двигунів шляхом організації їх контролю технічного стану в процесі експлуатації та ремонту. У роботі системно розглянуто стан експлуатаційної надійності тягових електричних двигунів тролейбусів. Проаналізовано стан питання надійності вузлів тролейбусів за видами обладнання, особливості роботи та основні напрямки підвищення надійності тягових електричних двигунів. Розроблено структурні схеми елементів тягових електричних двигунів та запропоновано математичні моделі оцінки технічного стану їх основних електротехнічних функціональних складових у процесі експлуатації. Досліджено експлуатаційну надійність елементів тягових електродвигунів тролейбусів за величиною їх зносу в процесі експлуатації. Обґрунтовано діагностичні параметри та методи їх контролю. Розроблено технічні вимоги до пристроїв та програмного забезпечення для системи автоматизованого діагностування тягових електричних двигунів тролейбусів.
RU: АННОТАЦИЯ Диссертационная работа посвящена решению актуальной научной задачи – повышение надежности тяговых электродвигателей путем организации их контроля технического состояния в процессе эксплуатации и ремонта. Обоснована необходимость построения моделей надежности с учетом структурных и функциональных характеристик тяговых электродвигателей троллейбусов, как важных факторов повышения эксплуатационного ресурса. Предложены структурно-функциональные модели элементов тяговых электрических двигателей учитывают практически весь диапазон требований, предъявляемых к таким системам и обеспечивает высокую точность. Разработаны критерии и классификация элементной базы тягового двигателя, которые учитывают особенности внутренней структуры и функциональные связи, позволяющих формировать модели надежности их узлов. Предложены методы построения структурных моделей, которые учитывают особенности конструкции, а также характеристики электрических и магнитных цепей, влияющих на надежность системы. Разработаны математические модели надежности элементов тяговых электродвигателей и методы их формирования, которые качественно отличаются от существующих тем, что учитывают конструктивные, электромагнитные характеристики тягового электрического двигателя троллейбуса. Разработаны универсальные модели надежности, которые позволяют оптимизировать параметры различных узлов применительно к требованиям системы планово-предупредительного ремонта, когда тяговые двигатели отработали заданный ресурс и продолжают эксплуатироваться. В результате проведенных исследований получены количественные характеристики надежности коллекторно-щеточного узла. Определены законы распределения и их параметров. Все это позволяет оценить наработки между постепенными отказами. Проанализированы устройства и программное обеспечение для систем диагностирования тяговых электродвигателей и технические требования к ним с целью усовершенствования и разработки мероприятий, которые направлены на повышение надежности тяговых электрических двигателей троллейбусов. Разработан алгоритм и программа расчета матриц оценивания ранга элементов системы, учитывающие характеристики связей между узлами. Исследования показывают, что надежность и ресурс элементов системы обусловлены внешними воздействиями и условиями функционирования. Поэтому точность оценки будет зависеть от правильной статистической оценки элементов системы. Для этого необходимо выполнить требования типизации режимов нагрузки тяговых электродвигателей, как динамической системы. Определение вероятностно-статистических характеристик и законов плотности распределения параметров надежности требует исследования постепенных и внезапных отказов элементов, на примере исследования наименее надежных элементов, которые в эксплуатации снижают характеристики технического состояния. По результатам проведенных исследований рекомендована для практических расчетов в условиях эксплуатации методика, где учитываются структурно-функциональные свойства тяговых электродвигателей, что дает возможность повысить точность оцениваемых параметров системы планово-предупредительных ремонтов троллейбусов и повысить эффективность работы парка троллейбусов за счет снижения отказов в период между ремонтами.
EN: ABSTRACT The thesis is devoted to the resolution of relevant scientific tasks – improving the reliability of traction motors by organizing their control of a technical condition in the process of operation and repair. In the work systematically reviewed the status of the operational reliability of traction electric motor. Analyzes the state of the question the reliability of the nodes of the trolley on the equipment, especially the work and the main directions of improving the reliability of the electric traction motors. Developed structural diagram of the elements of the traction electric motors and mathematical models evaluate the technical condition of their basic electrical functional components during operation. Investigated the operational reliability of the elements of trolleybus traction motors on the magnitude of wear during operation. Justified diagnostic parameters and methods of their control. Developed technical requirements for devices and software for computer-aided diagnosis of traction electric motors trolleybuses.
Харківський національний університет міського господарства імені О. М. Бекетова
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Chen, Xuanwu. "A Framework for Recommending Signal Timing Improvements Based on Automatic Vehicle Matching Technologies." FIU Digital Commons, 2016. http://digitalcommons.fiu.edu/etd/3003.
Повний текст джерелаАнотація:
Continuously monitoring and automatically identifying existing problems in traffic signal operation is a challenging and time-consuming task. Although data are becoming available due to the adoption of emerging detection technologies, efforts on utilizing the data to diagnose signal control are limited. The current practices of retiming signals are still periodic and based on several days of aggregated turning movement counts. This dissertation developed a framework of automatic signal operation diagnosis with the aim to support decision-making processes by assessing the signal control and identifying the signal retiming needs. The developed framework used a combination of relatively low-cost data from Wi-Fi sensors and historical signal timing records from existing signal controllers.
The development involved applying multiple data matching and filtering algorithms to allow the estimation of travel times of vehicular traversals. The Travel Time Index (TTI) was then used as a measure to assess the traffic conditions of various movements. Historical signal timing records were also analyzed, and an additional signal-timing measure, referred to as the Max-out Ratio (MR), was proposed to evaluate the frequency in which the green time demand of a phase exceeded its preset value.
Thresholds for the TTI and MR variables were used as a basis for the diagnosis. This diagnosis first identified the needs for assigning additional green times for individual signal phases. Further assessments were then made to determine whether or not the cycle length for the entire intersection or capacity was sufficient.
The developed framework was implemented in a real-world signalized intersection and proved to be capable of identifying retiming needs, as well as providing support for the retiming process. Compared to field observations, the diagnosis results were able to reflect the signal operations of most of the movements during various time periods. Moreover, the flexibility of the developed framework allows users to select different thresholds for various movements and times of day, and thus customize the analysis to agency needs.
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Materano, Antonella. "The building blocks of social entrepreneurship: empirical model and framework." Master's thesis, NSBE - UNL, 2013. http://hdl.handle.net/10362/11631.
Повний текст джерелаАнотація:
A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and EconomicsThe purpose of this exploratory study is to identify a common path followed by social entrepreneurs, so as to build a comprehensive empirical model. The methodology used is qualitative interviews; in particular, semi-structured questions were addressed to a sample of ten social entrepreneurs, whose answers were transcribed and analysed. The main result is represented by a five-stage pattern followed by social entrepreneurs: each stage is firstly described and further linked to specific challenges that social entrepreneurs face and assets they need during the process. It is fundamental to highlight that some of these stages and challenges are peculiar to social entrepreneurship, differing from regular entrepreneurship. The key conclusion is that it is possible to identify a common pattern that could guide current and future social entrepreneurs. Furthermore, this research paper emphasises best practices and lesson learned from current social entrepreneurs by leaving a powerful heritage to who is interested in make a real change in society.
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Bhatnagar, Rajiv. "A knowledge-based operator advisor system for integration of fault detection, control, and diagnosis to enhance the safe and reliable operation of nuclear power plants /." The Ohio State University, 1989. http://rave.ohiolink.edu/etdc/view?acc_num=osu148767110830585.
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Silva, Filho Pedro Alves da. "Diagn?stico operacional de lagoas de estabiliza??o." Universidade Federal do Rio Grande do Norte, 2007. http://repositorio.ufrn.br:8080/jspui/handle/123456789/16020.
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Previous issue date: 2007-05-07This work intends to develop an approach based through scientific criteria in the operational diagnosis of ponds of stabilization, starting from analyses accomplished in loco and in laboratory of 78 systems of sewer treatment through ponds of stabilization in the State of Rio Grande do Norte. The objectives of the research are: to map, to evaluate and to diagnose the operational acting of the ponds of stabilization of the state of Rio Grande do Norte, through visits in loco and analyses laboratory; to build a SIG, through the map rain, locate the points of releases of sewages of the systems of existent ponds in Rio Grande do Norte, as well as operational data and his/her respective efficiency diagnosis in the removal of BOD and Coliforms Termotolerantes; to evaluate, in real scale, three systems of ponds of stabilization of RN in the operational efficiency for the parameters BOD5, COD, pH, Temperature, OD and Coliforms Termotolerantes. Of 78 ETEs of appraised RN just, 9% or 7 had maximum concepts in what concerns the removal of BOD and Coliforms Termotolerantes and 41% or 32, they had the worst concepts in term of operational efficiency. The flowing concentrations ETEs of RN of BOD and Coliforms were of 410mg/L and 2,50x107UFC/100ml, the predominant configuration is of the type F1+M1+M2, the relationship BOD/COD revealed for the sewer tributary characteristic biodegradable high. For the study of case of 3 ETEs, the best operational efficiencies in decreasing order were: Cidade (Municipal district), it Ro?a (State) and S?o Miguel (SAAE). The removals of final BOD were 51,6mg/L; 108,27mg/L and 62,6mg/L, tends efficiency of 82%; 74% and 81%. In term of coliforms removal in the final effluentes were 1,90x103UFC/100ml; 1,50x104UFC/100ml and 3,10x104UFC/100ml, tends efficiencies of 99,99%; 99,95% and 99,90%. In what it concerns the practice of agricultural re?so of cultures consumed raw, none of 3 ETEs assisted the parameters of the Resolution CONAMA 357/05, for other re?so practices, all assisted the categories B and C of OMS. For release in body receiving ETE Cidade just, they assist the demands of the resolution of CONAMA 357/05, by study of purification solemnity of the receiving body. The maintenance lack and operation; exclusive operator in ETEs and operation knowledge was the contributory factors for the operational fall in appraised ETEs of RN
Este trabalho se prop?e a desenvolver uma abordagem fundamentada atrav?s de crit?rios cient?ficos no diagn?stico operacional de lagoas de estabiliza??o, a partir de an?lises realizadas in loco e em laborat?rio de 78 sistemas de tratamento de esgoto por meio de lagoas de estabiliza??o no Estado do Rio Grande do Norte. Os objetivos da pesquisa s?o: mapear, avaliar e diagnosticar o desempenho operacional das lagoas de estabiliza??o do estado do Rio Grande do Norte, atrav?s de visitas in loco e an?lises laboratoriais; construir um SIG, atrav?s do mapa hidrogr?fico, locar os pontos de lan?amentos de efluentes dos sistemas de lagoas existentes no Rio Grande do Norte, como tamb?m dados operacionais e seu respectivo diagn?stico de efici?ncia na remo??o de DBO e Coliformes Termotolerantes; avaliar, em escala real, tr?s sistemas de lagoas de estabiliza??o do RN na efici?ncia operacional para os par?metros DBO5, DQO, pH, Temperatura, OD e Coliformes Termotolerantes. Das 78 ETEs do RN avaliadas apenas, 7 lagoas correspondente a 9%, tiveram conceito: Bom, que concerne a remo??o de DBO e Coliformes Termotolerantes e 32 lagoas correspondente a 41%, tiveram conceito: Ruim, em termo de efici?ncia operacional, para os par?metros de DBO e Coliformes Termotolerantes. As concentra??es m?dias afluentes as ETEs do RN de DBO e Coliformes foram de 410mg/L e 2,50x107UFC/100ml, a configura??o predominante ? do tipo F1+M1+M2 (Facultativa prim?ria, seguida por duas lagoas de matura??o, uma prim?ria e outra secund?ria) , a rela??o DBO/DQO revelou para o esgoto afluente caracter?sticas biodegrad?veis. Para o estudo de caso, envolvendo as 3 ETEs, uma para cada ?rg?o de gest?o, as melhores efici?ncias operacionais em ordem decrescente foram: Cidade (Munic?pio), Ro?a (Estado) e S?o Miguel (SAAE). As remo??es de DBO final foram 51,6mg/L; 108,27mg/L e 62,6mg/L, tendo efici?ncia de 82%; 74% e 81%, respectivamente. Em termo de remo??o de coliformes nos efluentes das ETEs foram 1,90x103UFC/100ml; 1,50x104UFC/100ml e 3,10x104UFC/100ml, tendo efici?ncias de 99,99%; 99,95% e 99,90%. No que concerne a pr?tica de re?so de culturas consumidas cruas, nenhumas das 3 ETEs atenderam aos par?metros da Resolu??o CONAMA 357/05, para outras pr?ticas de re?so, todas atenderam as categorias B e C da OMS. Para lan?amento em corpo receptor h?drico apenas a ETE Cidade, atende as exig?ncias da resolu??o do CONAMA 357/05, mediante estudo de autodepura??o do corpo receptor. A falta de manuten??o e opera??o; operador exclusivos nas ETEs e conhecimento de opera??o foram os fatores contribuintes para o diminuto quadro de efici?ncia no que concerne a remo??o final de DBO e Coliformes Termotolerantes nas ETEs avaliadas do RN
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池田, 充., Mitsuru Ikeda, 茂樹 伊藤, Shigeki Ito, 武男 石垣, Takeo Ishigaki, Kazunobu Yamauchi, and 一信 山内. "Evaluation of a neural network classifier for pancreatic masses based on CT findings." Elsevier, 1997. http://hdl.handle.net/2237/5311.
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Khamesipour, Alireza. "IMPROVED GENE PAIR BIOMARKERS FOR MICROARRAY DATA CLASSIFICATION." OpenSIUC, 2018. https://opensiuc.lib.siu.edu/dissertations/1573.
Повний текст джерелаАнотація:
The Top Scoring Pair (TSP) classifier, based on the notion of relative ranking reversals in the expressions of two marker genes, has been proposed as a simple, accurate, and easily interpretable decision rule for classification and class prediction of gene expression profiles. We introduce the AUC-based TSP classifier, which is based on the Area Under the ROC (Receiver Operating Characteristic) Curve. The AUCTSP classifier works according to the same principle as TSP but differs from the latter in that the probabilities that determine the top scoring pair are computed based on the relative rankings of the two marker genes across all subjects as opposed to for each individual subject. Although the classification is still done on an individual subject basis, the generalization that the AUC-based probabilities provide during training yield an overall better and more stable classifier. Through extensive simulation results and case studies involving classification in ovarian, leukemia, colon, and breast and prostate cancers and diffuse large b-cell lymphoma, we show the superiority of the proposed approach in terms of improving classification accuracy, avoiding overfitting and being less prone to selecting non-informative pivot genes. The proposed AUCTSP is a simple yet reliable and robust rank-based classifier for gene expression classification. While the AUCTSP works by the same principle as TSP, its ability to determine the top scoring gene pair based on the relative rankings of two marker genes across {\em all} subjects as opposed to each individual subject results in significant performance gains in classification accuracy. In addition, the proposed method tends to avoid selection of non-informative (pivot) genes as members of the top-scoring pair.\\ We have also proposed the use of the AUC test statistic in order to reduce the computational cost of the TSP in selecting the most informative pair of genes for diagnosing a specific disease. We have proven the efficacy of our proposed method through case studies in ovarian, colon, leukemia, breast and prostate cancers and diffuse large b-cell lymphoma in selecting informative genes. We have compared the selected pairs, computational cost and running time and classification performance of a subset of differentially expressed genes selected based on the AUC probability with the original TSP in the aforementioned datasets. The reduce sized TSP has proven to dramatically reduce the computational cost and time complexity of selecting the top scoring pair of genes in comparison to the original TSP in all of the case studies without degrading the performance of the classifier. Using the AUC probability, we were able to reduce the computational cost and CPU running time of the TSP by 79\% and 84\% respectively on average in the tested case studies. In addition, the use of the AUC probability prior to applying the TSP tends to avoid the selection of genes that are not expressed (``pivot'' genes) due to the imposed condition. We have demonstrated through LOOCV and 5-fold cross validation that the reduce sized TSP and TSP have shown to perform approximately the same in terms of classification accuracy for smaller threshold values. In conclusion, we suggest the use of the AUC test statistic in reducing the size of the dataset for the extensions of the TSP method, e.g. the k-TSP and TST, in order to make these methods feasible and cost effective.
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Sun, Fangfang. "Semi-parametric inference for the partial area under the ROC curve." unrestricted, 2008. http://etd.gsu.edu/theses/available/etd-11192008-113213/.
Повний текст джерелаАнотація:
Thesis (M.S.)--Georgia State University, 2008.Title from file title page. Gengsheng Qin, committee chair; Yu-Sheng Hsu, Yixin Fang, Yuanhui Xiao, committee members. Description based on contents viewed July 22, 2009. Includes bibliographical references (p. 29-30).
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Radoje, Simić. "Kliničke i patohistološke karakteristike urođenog rascepa vrata u prednjoj srednjoj liniji i njihov značaj za diferencijalnu dijagnozu i hirurško lečenje." Phd thesis, Univerzitet u Novom Sadu, Medicinski fakultet u Novom Sadu, 2015. https://www.cris.uns.ac.rs/record.jsf?recordId=94511&source=NDLTD&language=en.
Повний текст джерелаАнотація:
Urođeni rascep sa naborom u prednjoj srednjoj liniji vrata (UR-N PSLV) je retka anomalija sa oko 100-150 bolesnika opisanih u literaturi. Tipičan rascep se sastoji od atrofične, ružičaste kože u obliku žleba, kožne prominencije na gornjem kraju i potkožnog sinusa na donjem kraju tzv. rascepa. Ispod ovih elemenata nalazi se potkožna vezivno-mišićna traka koja izaziva nabor na vratu. Izolovani nabor vrata, kao jedan od tipova rascepa, ima samo potkožnu traku i podbradnu kožnu izraslinu. U radu analiziramo seriju od 11 bolesnika sa UR-N PSLV operisanih u periodu od 12 godina (jul 1998. - jun 2010.). Rezultati lečenja sagledani su u pogledu preciznosti postavljanja dijagnoze (diferencijalna dijagnoza anomalija i oboljenja PSLV) i analize posleoperativnih funkcionalnih i estetskih karakteristika (vrednost cervikomentalnog ugla-CMU, veličina ekstenzije glave i vrata-EGV i karakteristike ožiljka). Rezultati operativnog lečenja rascepa primenom multiple „Z” plastike sa 4-10 kožnih režnjeva poređeni su sa Sistrunkovom operacijom kod bolesnika sa cistom tiroglosnog duktusa-TGDC (ukupno 128 bolesnika u seriji). S obzirom na veliki broj bolesnika sa različitim izgledom anomalije učinjena je podela UR-N PSLV na tipove (I-IV) i podtipove. Rascep se po embriopatogenezi, izgledu i patohistološkim (PH) karakteristikama jasno razlikuje od TGDC. Deskriptivnom embriologijom rascep se definiše kao poremećaj u spajanju prednjih krajeva II (nekad i I) ždrelnih lukova. Kompresija srca u razvoju i odloženo ispravljanje vrata imaju značajnu ulogu. Kožna izraslina je rabdomiomatozni mezenhimalni hamartom kod svih naših bolesnika. Kaudalni sinus po PH izgledu ukazuje na bronhogeno poreklo. Operacijom rascepa vrata ne postiže se normalan CMU i potpuna EGV. Operacijom TGDC više se menja CMU nego EGV, ali su vrednosti bliže kontrolnoj grupi nego kod dece sa rascepom. Ožiljci, posebno kosi delovi „Z” plastike, posle operacije UR-N su lošije ocenjeni nego posle operacije TGDC (parametrijski testovi pokazuju manju razliku). Na estetiku i funkcionalnost vrata i glave posle operacije rascepa veoma mnogo utiču hipoplazija donje vilice i deficit mekih struktura prednje strane vrata. Nova operativna tehnika (poprečna eliptična ekscizija i incizija u dva nivoa ili step incision, sa dodatnom „Z” plastikom na platizmi) primenjena kod dva bolesnika (pri kraju analize rezultata u studiji) daje nadu u dobijanje boljih posleoperativnih rezultata.Congenital midline cervical cleft and web (CMCC-W) is a rare anomaly with about 100-150 cases described in the literature. The typical CMCC consists of midline groove of atrophic, erythematous skin with a skin protuberance cranially, and a subcutaneous blind sinus tract on the lower end of so-called cleft. Subcutaneous fibro-muscular band is located underneath, causing the web. Isolated CMCW, as one of the cleft types, includes only subcutaneous band and submental skin prominence. We analyzed a series of 11 patients with CMCC-W during the 12-year period (July 1998-June 2010). Treatment outcomes were evaluated according to precisely established diagnosis (differential diagnosis of anomalies and diseases of midline neck) and analysis of postoperative functional and aesthetic features (value of cervico-mental angle (CMA), head and neck extension (HNE) and characteristics of the scar). The results of the surgical treatment using multiple Z-plasty technique with 4-10 skin flaps were compared with Sistrunk procedure in patients with thyroglossal duct cyst (TGDC) (total of 128 patients in the series). Since a great number of patients had different forms of anomaly, the cases were divided into types (I-IV) and subtypes. Regarding embryo pathogenesis, appearance and histopathology, there was a clear difference between CMCC and TGDC. A cleft is defined, due to descriptive embryology, as a failure of the second (sometimes and first) pharyngeal arches to fuse in the midline. Compression of the heart and postponed extension of the neck played an important role during development period. Skin prominence was a rhabdomyomatous mesenchymal hamartoma in all our patients. Histopathology of the caudal sinus indicated the bronchogenic origin. The normal CMA and complete HNE were not achieved by the operation of CMCC-W. TGDC operation effects more CMA than HNE, but the values are closer to control group than in children having a cleft. Scars, especially oblique parts of Z plasty, after the operation CMCC-W were worse than after TGDC (parametric tests showed lesser difference). Hypoplasia of the mandible and vertical soft-tissue deficit of the anterior neck have a great impact on aesthetics and functionality of the head and neck after cleft surgery. New operative technique (two level transverse elliptical excision and incision or step incision – with the additional Z-plasty of platysma) was applied in two patients (at the end of the analysis of the results in the study) gives a new hope regarding better postoperative results.
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Vedreño, Santos Francisco Jose. "Diagnosis of electric induction machines in non-stationary regimes working in randomly changing conditions." Doctoral thesis, Universitat Politècnica de València, 2013. http://hdl.handle.net/10251/34177.
Повний текст джерелаАнотація:
Tradicionalmente, la detección de faltas en máquinas eléctricas se basa en el uso de la Transformada Rápida de Fourier ya que la mayoría de las faltas pueden ser diagnosticadas con ella con seguridad si las máquinas operan en condiciones de régimen estacionario durante un intervalo de tiempo razonable.
Sin embargo, para aplicaciones en las que las máquinas operan en condiciones de carga y velocidad fluctuantes (condiciones no estacionarias) como por ejemplo los aerogeneradores, el uso de la Transformada Rápida de Fourier debe ser reemplazado por otras técnicas.
La presente tesis desarrolla una nueva metodología para el diagnóstico de máquinas de inducción de rotor de jaula y rotor bobinado operando en condiciones no estacionarias, basada en el análisis de las componentes de falta de las corrientes en el plano deslizamiento frecuencia. La técnica es aplicada al diagnóstico de asimetrías estatóricas, rotóricas y también para la falta de excentricidad mixta.
El diagnóstico de las máquinas eléctricas en el dominio deslizamiento-frecuencia confiere un carácter universal a la metodología ya que puede diagnosticar máquinas eléctricas independientemente de sus características, del modo en el que la velocidad de la máquina varía y de su modo de funcionamiento (motor o generador).
El desarrollo de la metodología conlleva las siguientes etapas:
(i) Caracterización de las evoluciones de las componentes de falta de asimetría estatórica, rotórica y excentricidad mixta para las máquinas de inducción de rotores de jaula y bobinados en función de la velocidad (deslizamiento) y la frecuencia de alimentación de la red a la que está conectada la máquina.
(ii) Debido a la importancia del procesado de la señal, se realiza una introducción a los conceptos básicos del procesado de señal antes de centrarse en las técnicas actuales de procesado de señal para el diagnóstico de máquinas eléctricas.
(iii) La extracción de las componentes de falta se lleva a cabo a través de tres técnicas de filtrado diferentes: filtros basados en la Transformada Discreta Wavelet, en la Transformada Wavelet Packet y con una nueva técnica de filtrado propuesta en esta tesis, el Filtrado Espectral. Las dos primeras técnicas de filtrado extraen las componentes de falta en el dominio del tiempo mientras que la nueva técnica de filtrado realiza la extracción en el dominio de la frecuencia.
(iv) La extracción de las componentes de falta, en algunos casos, conlleva el desplazamiento de la frecuencia de las componentes de falta. El desplazamiento de la frecuencia se realiza a través de dos técnicas: el Teorema del Desplazamiento de la Frecuencia y la Transformada Hilbert.
(v) A diferencia de otras técnicas ya desarrolladas, la metodología propuesta no se basa exclusivamente en el cálculo de la energía de la componente de falta sino que también estudia la evolución de la frecuencia instantánea de ellas, calculándola a través de dos técnicas diferentes (la Transformada Hilbert y el operador Teager-Kaiser), frente al deslizamiento. La representación de la frecuencia instantánea frente al deslizamiento elimina la posibilidad de diagnósticos falsos positivos mejorando la precisión y la calidad del diagnóstico. Además, la representación de la frecuencia instantánea frente al deslizamiento permite realizar diagnósticos cualitativos que son rápidos y requieren bajos requisitos computacionales.
(vi) Finalmente, debido a la importancia de la automatización de los procesos industriales y para evitar la posible divergencia presente en el diagnóstico cualitativo, tres parámetros objetivos de diagnóstico son desarrollados: el parámetro de la energía, el coeficiente de similitud y los parámetros de regresión. El parámetro de la energía cuantifica la severidad de la falta según su valor y es calculado en el dominio del tiempo y en el dominio de la frecuencia (consecuencia de la extracción de las componentes de falta en el dominio de la frecuencia). El coeficiente de similitud y los parámetros de regresión son parámetros objetivos que permiten descartar diagnósticos falsos positivos aumentando la robustez de la metodología propuesta.
La metodología de diagnóstico propuesta se valida experimentalmente para las faltas de asimetría estatórica y rotórica y para el fallo de excentricidad mixta en máquinas de inducción de rotor de jaula y rotor bobinado alimentadas desde la red eléctrica y desde convertidores de frecuencia en condiciones no estacionarias estocásticas.Vedreño Santos, FJ. (2013). Diagnosis of electric induction machines in non-stationary regimes working in randomly changing conditions [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/34177
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