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1
Horký, Miroslav. "Modely hromadné obsluhy." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-232033.
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The master’s thesis solves models of queueing systems, which use the property of Markov chains. The queueing system is a system, where the objects enter into this system in random moments and require the service. This thesis solves specifically such models of queueing systems, in which the intervals between the objects incomings and service time have exponential distribution. In the theoretical part of the master’s thesis I deal with the topics stochastic process, queueing theory, classification of models and description of the models having Markovian property. In the practical part I describe realization and function of the program, which solves simulation of chosen model M/M/m. At the end I compare results which were calculated in analytic way and by simulation of the model M/M/m.
2
Song, Yuanjun. "Implementation of a Recoder Front-End." Thesis, Växjö University, School of Mathematics and Systems Engineering, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:vxu:diva-5553.
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VizzAnalyzer is a program analysis tool that can be used for analyzing software programs. It relies on so called Front-Ends for information extraction from various sources like C or Java source code. It allows analyzing different source code by mapping the language specific front-end meta-model onto a common meta-model, on which analysis are defined. Right now we use the Eclipse Parser for parsing Java source code. This requires an Eclipse installation involving a large number of dependencies in order to work with Java source code. Yet, this is not always feasible; we want to be independent from Eclipse using an alternative parser.
Recoder is a Java meta-programming application program interface (API) that can be used to write Java programs that manipulate and analyze other Java programs. The Recoder framework provides over an application programming interface detailed access to the source code in form of an abstract syntax tree (AST). It has a small footprint and no external dependencies.
We create the Recoder Front-End as alternative to the existing Eclipse front-end. This includes the definition of a mapping between Recoder Front-End Meta-Model to Common Meta-Model. The mapping result will be used by VizzAnalyzer to do further analysis work. This Bachelor thesis documents relevant theory regarding Recoder Front-End and discusses its development and implementation.
3
Van, Zyl Hillet. "Innovation models and the front-end of product innovation." Thesis, Link to the online version, 2006. http://hdl.handle.net/10019/1280.
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Chavez, Rodriguez Adolfo 1951. "Modeling mountain-front recharge to regional aquifers." Diss., The University of Arizona, 1987. http://hdl.handle.net/10150/191124.
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The estimation of mountain-front recharge to regional aquifers is approached from a hydroclimatic standpoint. Analytical models of the seasonal water yield and streamflow are developed in this dissertation. These models are specialized for hard-rock mountainous watersheds where deep percolation occurs through fractures exclusively. Input variables are considered to be stochastic, and a relationship between precipitation and surface runoff is derived by using a deterministic physical process. Streamflow models for the summer and winter rainy seasons are developed separately in terms of known parameters of the storm process and unknown parameters of the physical process. The winter model considers the generation of surface runoff from both rainfall and snowmelt. These models include the long-term effective subsurface outflow from the mountainous watershed, or mountain-front recharge, as one of the parameters to be identified. The parameter estimation problem is posed in the framework of maximum likelihood theory, where prior information about the model parameters and a suitable weighting scheme for the error terms in the estimation criterion are included. The issues of model and parameter identifiability, uniqueness and stability are addressed, and strategies to mitigate identifiability problems in our modeling are discussed. Finally, the seasonal streamflow models are applied to three mountainous watersheds in the Tucson basin, and maximum likelihood estimates of mountain-front recharge and other model and statistical parameters are obtained. The analysis of estimation errors is performed in both the eigenspace and the original space of the parameters.
5
Ferris, P. D. "Frontal structure in a mesoscale model." Thesis, University of Reading, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234649.
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Alvarado, Mamani Ulises. "Aplicación de indicadores nativos de fluorescencia para la evaluación rápida de daño térmico en el procesado de leche." Doctoral thesis, Universitat Autònoma de Barcelona, 2017. http://hdl.handle.net/10803/406093.
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L'objectiu d'aquesta tesi és l'aplicació d'indicadors nadius de fluorescència per a
la quantificació ràpida dels canvis generats per la calor en diversos marcadors
de dany tèrmic, com ara: hidroximetilfurfural (HMF), grups sulfhidril (-SH), àcid
ascòrbic (AA ) i riboflavina (RBF) en llet desnatada mitjançant espectroscòpia de
fluorescència "front-face".
Es van dur a terme quatre experiments; en els dos primers es va estudiar la
cinètica de desaparició i / o aparició dels marcadors indicats i, es van construir
models cinètics a partir de la informació generada, així com de predicció
mitjançant marcadors de fluorescència. En el tercer experiment, amb la utilització
de dos fluorímetres diferents (sobretaula i fibra òptica), es van validar i recalibrar
els models de predicció obtinguts anteriorment, emprant mostres generades en
planta pilot en condicions industrials.
En el cas dels models cinètics, aquests van ser validats i recalibrats combinant
dades dels tres experiments per tal d'ampliar el nombre de mostres i obtenir
models millorats. L'aparició i / o degradació dels marcadors químics estudiats es
va ajustar a cinètiques de primer ordre. Es van estimar alguns paràmetres
cinètics com ara l'energia d'activació, constant preexpronencial d'Arrhenius i
coeficient tèrmic.
Durant el procés de validació dels models matemàtics de predicció dels
marcadors, indicadors estadístics com ara CV (coeficient de variació) i SEP (error
estàndard de predicció) van resultar elevats; més encara amb les dades de fibra
òptica, a causa de diferències de configuració òptica entre els espectròmetres de
sobretaula i fibra òptica. Per això es va realitzar per una banda un recalibrat dels
models de sobretaula amb les dades dels tres experiments, si bé en el cas de
l'equip de fibra òptica es va procedir al calibratge emprant exclusivament dades
de planta pilot generats amb el tercer experiment i consegüent validació
mitjançant el mètode de validació creuada "leave one out". La fluorescència del
triptòfan, compostos intermedis de Maillard i riboflavina excitada a 370 nm van
ser els predictors més importants en el calibratge dels models. El millor model
seleccionat tant per a l'equip de sobretaula com per al de fibra òptica va ser el
corresponent a la predicció de l'àcid ascòrbic amb CV <12% mentre que els
models amb major variabilitat d'error van ser els del hidroximetilfurfural amb CV
<45%.
En un quart experiment es va desenvolupar un mètode de quantificació ràpida
de riboflavina mitjançant la mesura de fluorescència "front-face". Els valors
obtinguts amb el model desenvolupat per quantificar la riboflavina en llets
comercials no van ser significativament diferents dels obtinguts amb els mètodes
convencionals (HPLC).
La fluorescència "front-face" és un mètode ràpid, senzill i sense manipulació de
mostra que permet calibrar models de predicció dels marcadors de dany tèrmic
en llet. L'aplicació en línia dels models desenvolupats presenta potencial per a la
millora del control dels tractaments tèrmics en llet, si bé els resultats obtinguts
fins al moment indiquen que la implementació dels mateixos requeriria una etapa
prèvia de calibratge en planta.El objetivo de esta tesis es la aplicación de indicadores nativos de fluorescencia para la cuantificación rápida de los cambios generados por el calor en varios marcadores de daño térmico, tales como: hidroximetilfurfural (HMF), grupos sulfhidrilo (-SH), ácido ascórbico (AA) y riboflavina (Rbf) en leche desnatada mediante espectroscopía de fluorescencia “front-face”. Se llevaron a cabo cuatro experimentos: en los dos primeros se estudió la cinética de desaparición y/o aparición de los marcadores indicados y, a partir de la información generada, se construyeron modelos cinéticos, así como de predicción mediante marcadores de fluorescencia. En el tercer experimento, con la utilización de dos fluorímetros diferentes (sobremesa y fibra óptica), se validaron y recalibraron los modelos de predicción obtenidos anteriormente, empleando muestras generadas en planta piloto en condiciones industriales. En el caso de los modelos cinéticos, éstos fueron validados y recalibrados combinando datos de los tres experimentos a fin de ampliar el número de muestras y obtener modelos mejorados. La aparición y/o degradación de los marcadores químicos estudiados se ajustó a cinéticas de primer orden. Se estimaron algunos parámetros cinéticos tales como la energía de activación, la constante preexponencial de Arrhenius y el coeficiente térmico. Durante el proceso de validación de los modelos matemáticos de predicción de los marcadores, los indicadores estadísticos tales como CV (coeficiente de variación) y SEP (error estándar de predicción) resultaron elevados; más aún con los datos de fibra óptica, debido a diferencias de configuración óptica entre los espectrómetros de sobremesa y de fibra óptica. Por ello se realizó por una parte un recalibrado de los modelos de sobremesa con los datos de los tres experimentos, si bien en el caso del equipo de fibra óptica se procedió a la calibración empleando exclusivamente datos de planta piloto generados con el tercer experimento y consiguiente validación mediante el método de validación cruzada “leave one out”. La fluorescencia del triptófano, los compuestos intermedios de Maillard y la riboflavina excitada a 370 fueron los predictores más importantes en la calibración de los modelos. El mejor modelo seleccionado tanto para el equipo de sobremesa como para el de fibra óptica fue el correspondiente a la predicción del ácido ascórbico con CV<12% mientras que los modelos con mayor variabilidad de error fueron los del hidroximetilfurfural con CV<45%. En un cuarto experimento se desarrolló un método de cuantificación rápida de riboflavina mediante la medida de fluorescencia “front-face”. Los valores obtenidos con el modelo desarrollado para cuantificar la riboflavina en leches comerciales no fueron significativamente diferentes de los obtenidos con los métodos convencionales (HPLC). La fluorescencia “front-face” es un método rápido, sencillo y sin manipulación de muestra que permite calibrar modelos de predicción de los marcadores de daño térmico en leche. La aplicación en línea de los modelos desarrollados presenta un gran potencial para la mejora del control de los tratamientos térmicos en leche, si bien los resultados obtenidos hasta el momento indican que la implementación de los mismos requeriría una etapa previa de calibración en planta.
The objective of this thesis is the application of native indicators of fluorescence for the rapid quantification of heat-induced changes in several thermal damage markers, such as hydroxymethylfurfural (HMF), sulfhydryl groups(-SH), ascorbic acid (AA) and riboflavin (Rbf) in skim milk by front-face fluorescence spectroscopy. Four experiments were carried out: in the first two, the kinetics of disappearance and / or appearance of the indicated markers were studied and kinetic models were constructed from the information generated as well as prediction models by fluorescence markers. In the third experiment, with the use of two different fluorimeters (benchtop and optic fiber), the prediction models previously obtained were validated and recalibrated using samples generated in a pilot plant under industrial conditions. In the case of kinetic models, these were validated and recalibrated by combining data from the three experiments in order to increase the number of samples and obtain improved models. The appearance and / or degradation of the chemical markers studied was adjusted to first order kinetic equations. Some kinetic parameters such as activation energy, Arrhenius pre-exponential constant and thermal coefficient were estimated. During the validation process of the markers prediction models, statistical indicators such as CV (coefficient of variation) and SEP (standard error of prediction) were high; even higher with optic fiber data, due to differences in optical configuration between benchtop and optic fiber spectrometers. For this reason, a recalibration of the benchtop models with the data of the three experiments was carried out, although in the case of optic fiber equipment, calibration was carried out exclusively using the pilot plant data generated in the third experiment and validation using the leave one out cross validation method. The fluorescence of tryptophan, intermediates compounds of Maillard reaction and riboflavin excited at 370 nm were the most important predictors in the calibration of the models. The best model selected for both the benchtop and optic fiber equipment was the prediction of ascorbic acid with CV <12%, while the models with the highest error variability were for hydroxymethylfurfural with CV <45%. In a fourth experiment, a rapid quantification method of riboflavin was developed by the measurement of front-face fluorescence. The values obtained with the model developed to quantify riboflavin in commercial milks were not significantly different from those obtained with conventional methods (HPLC). Front-face fluorescence is a fast, simple method. Without the need of sample manipulation, allows calibration of thermal damage predictive models. The inline application of the developed models presents potential for the improvement of the control of thermal treatments in milk, although the results obtained so far indicate that the implementation of the models would require a previous stage of calibration in plant.
7
Lodico, Marc Richard. "SQLSDM : a SQL front-end semantic data model /." Online version of thesis, 1989. http://hdl.handle.net/1850/10620.
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Slámová, Kateřina. "Simulace stochastických modelů hromadné obsluhy." Master's thesis, Vysoká škola ekonomická v Praze, 2007. http://www.nusl.cz/ntk/nusl-932.
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Práce vystihuje teoretické poznatky z oblasti teorie hromadné obsluhy a simulace a následně jsou aplikovány poznatky do praxe. Pro případovou studii je využíván simulační software Simul8 a podpůrný program Crystal Ball, pomocí nichž je vytvořen model. Cílem je navrhnout nejlepší řešení daného problému a zhodnotit systém z hlediska struktury a funkčnosti. S modelem je provedeno několik experimentů a následně je posouzena vhodnost či nevhodnost použití jednotlivých variant.
9
Barquet, Ana Paula Bezerra. "Creation of product-service systems (PSS) proposals in the fuzzy front-end." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/18/18156/tde-04052015-101933/.
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Product-service systems (PSS), defined as a system of products, services, infrastructure, and networks that aims to satisfy customer needs, support business innovation and has the potential to lead to improved environmental performance. The adoption of PSS requires modifications in the business model of companies or even the creation of new ones. The decision to modify or create business models occurs in the fuzzy front-end through the development of proposals. In this sense, the creation of PSS proposals might assist the adoption of PSS business models in enterprises. However, companies still need support to adopt PSS business models due to three main reasons. First, most of the studies about PSS business models mention its importance but do not explore which content should compose such models. Second, PSS business models are explored considering a partial view of business model dimensions. Finally, there is a lack of methods and tools that support the adoption of PSS business models in the fuzzy front-end. Thereby, the aim of this study is to develop a method, named Configurator of PSS Proposals, to cope with these challenges and assist the creation of PSS proposals for current or new business models. By means of systematic literature review, consulting with experts and an explorative case study, the method was developed. It is composed by eight steps and each step addresses a business model dimension, e.g. value proposition. The steps encompass a range of tasks that must be performed in order to create a PSS proposal. To support carrying out the tasks, a help element is available. This help contains additional information to support the utilization of the method, such as: examples of companies that adopted PSS and hints of practices, methods and tools. To evaluate the method, it was applied through a case study in the context of a research project. The aim was to create a PSS proposal for a bicycle concept and verify whether the method reach its purpose, i.e. is able to support the creation of a PSS proposal. Final considerations include contributions and limitations of this study. An example of contribution of the method is provision of a shared knowledge about PSS between different areas of expertise. As limitation, the lack of application of the method in a real case is highlighted. Additionally, future research is addressed based mainly on the insights gathered in the second case study, e.g. the inclusion of new tasks and relations between them.Sistema produto-serviço (SPS), definido como um sistema de produtos e serviços, infraestrutura e networks e que visa aumentar a satisfação de clientes, auxilia na inovação nos negócios e tem o potencial de levar à melhoria de desempenho ambiental. A adoção de SPS requer a criação ou modificação dos modelos de negócios das empresas. A decisão de criar ou modificar um modelo de negócio ocorre no fuzzy front-end por meio da criação de propostas. Desta forma, acredita-se que criação de propostas para SPS auxilia na adoção de modelos de negócio para SPS. No entanto, empresas requerem auxilio na adoção de modelos de negócio para PSS devido a três principais motivos. Primeiro, a maioria dos estudos sobre modelos de negócio para SPS mencionam sua importância, porém não exploram o conteúdo que deve compor esses modelos. Segundo, pesquisas sobre modelos de negócio para SPS levam em consideração uma visão parcial das dimensões de modelos de negócio. Finalmente, é constatada a carência de métodos e ferramentas que auxiliem na adoção de modelos de negócio para PSS no fuzzy front-end. O objetivo desse trabalho é desenvolver um método, denominado Configurador de Propostas de SPS, que guie empresas na criação de propostas de SPS para negócios novos e existentes. Por meio de revisão sistemática de literatura, consulta com especialistas e um estudo de caso exploratório, o método foi desenvolvido. Ele é composto por oito passos e cada passo aborda uma dimensão do modelo de negócios, como por exemplo, proposição de valor. Ainda, cada passo engloba várias tarefas que devem ser executadas para que a proposta de SPS seja criada. Como suporte para realizar as tarefas, um elemento ajuda foi criado. Este elemento inclui exemplos de empresas que adotaram SPS e dicas de práticas, métodos e ferramentas. Com objetivo de avaliar o método, uma aplicação no contexto de um projeto de pesquisa foi realizada, por meio de um estudo de caso. O objetivo dessa aplicação foi criar uma proposta de SPS para um conceito de uma bicicleta e verificar se o método alcança seu propósito, que é ajudar na criação de propostas de SPS. Considerações finais incluem contribuições e limitações do estudo. Um exemplo de contribuição do método é o fornecimento de um conhecimento compartilhado sobre PSS entre diferentes áreas de conhecimento. A falta de aplicação do método em um caso real é uma das limitações deste trabalho. Adicionalmente, pesquisas futuras são sugeridas, como por exemplo, a inclusão de novas tarefas no método e novas relações entre elas, conforme sugerido pelos participantes do segundo estudo de caso.
10
Li, Lin. "RF transceiver front-end design for testability." Thesis, Linköping University, Department of Electrical Engineering, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-2256.
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In this thesis, we analyze the performance of a loop-back built-in-self-test for a RF transceiver front-end. The tests aim at spot defects in a transceiver front-end and they make use of RF specifications such as NF (Noise Figure), G (power gain) and IIP3 (third order Intercept point). To enhance fault detectability, RF signal path sensitization is introduced. We use a functional RF transceiver model that is implemented in MatLab™ to verify this analysis.
11
Wood, R. A. "Instability of oceanic fronts." Thesis, University of Exeter, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.381309.
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Modesto, Francisco. "Development of a Java Bytecode Front-End." Thesis, Växjö University, School of Mathematics and Systems Engineering, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:vxu:diva-6210.
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The VizzAnalyzer is a powerful software analysis tool. It is able to extract information from various software representations like source code but also other specifications like UML. The extracted information is input to static analysis of these software projects. One programming language the VizzAnalyzer can extract information from is Java source code.
Analyzing the source code is sufficient for most of the analysis. But, sometimes it is necessary to analyze compiled classes either because the program is only available in byte-code, or the scope of analysis includes libraries that exist usually in binary form. Thus, being able to extract information from Java byte-code is paramount for the extension of some analyses, e.g., studying the dependecy structure of a project and the libraries it uses.
Currently, the VizzAnalyzer does not feature information extraction from Java byte-code. To allow, e.g., the analysis of the project dependency structure, we extend the VizzAnalyzer tool with a bytecode front-end that will allow the extraction of information from Java bytecode.
This thesis describes the design and implementation of the bytecode front-end. After we implemented and integrated the new front-end with the VizzAnalyzer, we are now able to perform new analyses that work on data extracted from both, source- and bytecode.
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Erol, Tugra. "Vibration Exposure Of Front Seat Car Passengers." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/2/12605740/index.pdf.
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Vibration in the vehicle environment has long been investigated considering the driver's exposure. However not only drivers but also the front seat car passengers are exposed to considerable amount of vibration. In order to investigate the phenomenon, this research consisted of three stages. In the first stage of the study, model analysis has been carried out. Based on the results it has been suggested that increased damping in the lumbar area in contact with the backrest can decrease the vibration transmission. The second stage comprised of the laboratory studies. Based on the results attained from the model, waist belts filled with different fluids having different coefficients of viscosity were prepared and tested. The inclination of the backrest angle was chosen as the second parameter. The cushions having ready-made gel mediums were seen to be effective in reducing low frequency vibrations where the angle of inclination affected the response of the cushions. In the third part of the thesis, field measurements were carried out in order to confirm the results attained in the laboratory. It was observed that the inclination of backrest angle played a major role in the exposure of the passenger in fore and aft direction. The cushions proved to be effective at certain frequencies in the field, differing due to the design and the medium.
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Sun, Wenjun, and 孫文君. "Front tracking algorithm for the Lighthill-Whitham-Richards model for a traffic network." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2008. http://hub.hku.hk/bib/B40687624.
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Valdivia, Caballero José Jesús. "Modelo de procesos para el desarrollo del front-end de aplicaciones web." Master's thesis, Universidad Nacional Mayor de San Marcos, 2021. https://hdl.handle.net/20.500.12672/17030.
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Desarrolla un modelo de procesos para el desarrollo del front-end de aplicaciones web para
PYMES, alineado a los estándares NTP-RT-ISO/IEC 29910 y Moprosoft con la finalidad de
mejorar la capacidad de procesos de desarrollo de software. Este modelo será validado mediante
una metodología de investigación y desarrollo con tres casos de estudio que son proyectos de
desarrollo de aplicaciones web bajo distintos tipos de arquitecturas de software; estos proyectos
son: Quinua Smart, Renovación Sitio Web COA y Concurso de Fotografía COA 2019.
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Yi, Guanyu. "A front-tracking solidification model and its application in modelling alloy solidification." Thesis, University of Leicester, 2010. http://hdl.handle.net/2381/8934.
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A front-tracking solidification model has been developed to simulate the dendritic structure evolution during alloy solidification. In the model the growth of dendrites is governed by heat and mass transport and a finite difference technique is employed to solve heat and solute diffusion during solidification. The model incorporates front-tracking technique to calculate and track the exact position of the Solid/Liquid (S/L) interface as a part of solution process and a new capture rule was designed and implemented in the model to efficiently track the growing S/L interface. The model has been evaluated and verified using simulated data from Al-Cu 4 wt. % alloy solidification. The effect of curvature undercooling on crystal growth was investigated. The simulated results reveal that solute redistribution, curvature of the S/L interface and anisotropy of interface tension are important factors in determining the dendritic morphology. The calculation of the S/L interface curvature and anisotropy of surface tension was found to be particularly important in determining the dendritic growth direction. Based on the above observations and simulated data, the parameters in the developed model have been optimised for predicting the solidification structure in binary alloys. Simulations of Al-Cu alloy solidification were then performed using the optimised model for single-grain and multi-grain solidification. The simulated results of single-grain growth were compared with the results from the Lipton-Glicksman-Kurz (LGK) model (Lipton et al. 1984). Solute profile ahead of the S/L interface was examined using different techniques for approximating solute profile in the growing cell. The solidification segregation in the multi-grain growth was investigated; and the dendritic evolution and solute interaction during multi-grain growth were investigated.
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Matthews, Waseem. "Multimodality and negotiation of Cape Flats identity in selected Daily Voice front pages." Thesis, University of the Western Cape, 2009. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_4688_1315294286.
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This thesis explores the social semiotic relationship of visual and verbal signs of the Daily Voice tabloid as a way to show how the social context influences meaning of the signs used in its multimodal frontpages. The Daily Voice tabloid largely uses Kaapse English/ Afrikaans as spoken by Coloureds on the Cape Flats on its frontpages rather than standard English or standard Afrikaans associated with White people. The study assumes that the meaning constructed by and through the verbal and visual signs on the Daily Voice frontpages is interdependent on the relationship the multimodal texts have with the largely Cape Flats readership. This study maintains the importance of the idea of the localisation of meaning in socio-cultural specific contexts throughout. I conclude that Kress and Van Leeuwen&rsquo
s (1996/2006) design could be extended beyond Westernised contexts and that marginalised discourses such as those unique to the Cape Flats are not static, but indeed dynamic. I also extend the appraisal theory by Martin and White (2005) to marginalised bilingual discourse and establish that Appraisal theory can be used to not only evaluate verbal discourse but also that visual discourse needs to be considered as a tool within the appraisal framework. I also conclude by suggesting a monolectal view of Kaapse English/Afrikaans discourse. That is, the meaning potential of Kaapse English/Afrikaans by Cape Flats speakers would be lost if perceived or analysed as emanating from two languages, (White) English and (White) Afrikaans. Therefore the conclusion is that the Daily Voice uses Kaapse English/Afrikaans as is used in Cape Flats socio-cultural contexts to construct meaning-making options across its frontpages.
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Young, Eliot F. (Eliot Fisher). "An albedo map and frost model of Pluto." Thesis, Massachusetts Institute of Technology, 1993. http://hdl.handle.net/1721.1/39974.
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Isern, Sardó Neus. "Front spreading in population dynamic models. Theory and application to the Neolithic transition." Doctoral thesis, Universitat de Girona, 2011. http://hdl.handle.net/10803/53462.
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This thesis presents population dynamics models that can be applied to predict the rate of spread of the Neolithic transition (change from hunter-gathering to farming economics) across the European continent, which took place about 9000 to 5000 years ago. The first models in this thesis provide predictions at a continental scale. We develop population dynamics models with explicit kernels and apply realistic data. We also derive a new time-delayed reaction-diffusion equation which yields speeds about a 10% slower than previous models. We also deal with a regional variability: the slowdown of the Neolithic front when reaching the North of Europe. We develop simple reaction-diffusion models that can predict the measured speeds in terms of the non-homogeneous distribution of pre-Neolithic (Mesolithic) population in Europe, which were present in higher densities at the North of the continent. Such models can explain the observed speeds.Aquesta tesi presenta models de dinàmica de poblacions que es poden aplicar a la transició del neolític (canvi d’una societat de caçadors-recol•lectors a una societat agrícola) per tal de predir-ne la velocitat d’expansió al continent europeu, que va tenir lloc fa entre 9000 i 5000 anys. Els primers models d’aquesta tesi proporcionen prediccions a escala continental. Desenvolupem models de dinàmica poblacional incloent kernels explícits i dades realistes. També demostrem una nova equació de reacció-difusió amb retard temporal la qual prediu velocitats fins a un 10% més lentes que en demostracions anteriors. També tractem una variabilitat regional: la disminució del ritme d’expansió del front neolític al nord d’Europa. Desenvolupem models de reacció-difusió senzills que tenen en compte la distribució no homogènia de poblacions preneolítiques (mesolítiques) a Europa, les quals eren presents amb majors densitats al nord del continent. Aquests models poden predir les velocitats mesurades.
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Lövqvist, Lisa. "Towards frost damage prediction in asphaltic pavements." Licentiate thesis, KTH, Bro- och stålbyggnad, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-251389.
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Roads are subjected to mechanical loads from the traffic as well as deteriorating mechanisms originating from the surrounding environment and climate. The damage arising is particularly severe during the winter season, when for example raveling, pot holes and cracks can emerge on the surfaces of asphaltic roads. These winter related damages are difficult to characterize and predict, partly due to the complexity of the asphalt material and partly since they cannot be linked to one single phenomenon but several, such as the (long term) existence of moisture, frost damage and frost heave, low temperature cracking and the embrittlement of the mastic at low temperatures. Further adding to the complexity is the combination of these phenomena which may accelerate the emergence and evolution of the damage mechanisms. This licentiate research project is mainly focusing on the emergence and development of frost damage in the asphalt layer but will include the effect of other damage mechanisms in its continuation. The goal of the project is to develop a multiscale model able to predict the damage development in an asphalt pavement during a desired period of time, to enhance maintenance predictions as well as pavement design choices. This licentiate thesis is the first part of this project and aims to lay the foundation of the multiscale model. To achieve this, a micromechanical model of frost damage in asphalt mixtures has been developed. This model couples the moisture and mechanical damage happening on the short and long term, caused by the infiltration of moisture and the expansion of water turning into ice during temperature drops. Both possible adhesive damage in the mastic-aggregate interface and cohesive damage in the mastic is included. In addition to the developed micromechanical model, this thesis presents the overall concept for the formulation of the multiscale model as well as discusses about its motivations and advantages.Vägar utsätts både för mekaniska laster från trafiken som kör på vägen samt för nedbrytande mekanismer härstammande från den omgivande miljön och klimatet. Skadorna som uppstår är särskilt stora under vintern, då till exempel stensläpp, potthål och sprickor kan uppstå på ytan av asfalterade vägar. Dessa vinterrelaterade skador är svåra att karakterisera och förutsäga, delvis på grund av det komplexa beteendet hos asfalt och delvis eftersom de inte härstammar från enbart ett fenomen utan flera, såsom existensen av fukt i asfalten (på lång sikt), frostskador, tjällyft, sprickbildning på grund av låg temperatur samt försprödningen av asfalt som sker vid låga temperaturer. Vidare påverkar dessa skademekanismer varandra vilket kan accelerera skadebildningen och utvecklingen, vilket ytterligare ökar komplexiteten. Detta licentiatforskningsprojekt fokuserar till största delen på uppkomsten och utvecklingen av frostskador men kommer även inkludera effekten av andra skademekanismer i dess fortsättning. Målet med detta forskningsprojekt är att utveckla en multiskalemodell som kan förutspå skadeutvecklingen i en asfaltsväg under en önskad tidsperiod, för att förbättra både underhållsprognoser samt designval. Denna licentiatuppsats är den första delen i detta projekt och syftar till att lägga grunden till multiskalemodellen. För att uppnå detta har en mikromekanisk modell av frostskador i asfalt utvecklats. Denna modell kopplar ihop fuktskadan och den mekaniska skadan som sker både på kort och lång sikt, orsakad av infiltrationen av fukt och expansionen av vatten som omvandlas till is vid sjunkande temperatur. Modellen inkluderar de möjliga skadorna som uppstår i både mastics och gränsskiktet mellan mastics och stenmaterialet. Utöver den utvecklade mikromekaniska modellen presenterar denna uppsats det övergripande konceptet för formuleringen av multiskalemodellen samt diskuterar dess motivering och fördelar.
QC20190515
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Heitmann, Bo-Lennart. "Full-stack musik : En studie om back-end, front-end och full-stack terminologi inom låtskapande och musikproduktion." Thesis, Kungl. Musikhögskolan, Institutionen för musik- och medieproduktion, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kmh:diva-4058.
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Syftet med det här examensarbetet är att presentera process och erfarenheter från mitt konstnärliga musikproduktionsprojekt som genomförts under mitt sista år av min masterutbildning. Genomförandet har bestått av att skapa ett svenskt popmusikalbum där låtar har skapats enskilt, genom samarbeten och tre verk har blivit slutförda och distribuerats på streamingtjänster så som Spotify och YouTube. Vidare är syfte att presentera en modell med hjälp av mitt konstnärliga arbete där det prövas potentiella omformuleringar för yrkesroller inom låtskapande. Dessa termer ska i sin tur underlätta rolldefinition inom låtskapande och även ge utrymme för att förtydliga den ideella rätten som medverkande i ett konstnärligt verk har. Med utgångspunkt till att musikproducenten ofta hamnar i en multikompetent position så har jag valt att låna begrepp från systemutvecklarens yrkesvärld för att skapa modellen. Begreppen jag valt att låna består av back-end, front-end och full-stack och avsikten är att bryta upp paraplybegrepp såsom ”låtskrivare, producent och performer” och även kunna bidra till tydligare rekryteringsprocesser för samarbeten inom låtskapande.The purpose of this master’s thesis is to present the process and experiences of my music production project that was carried out during the last year of my masters’ studies. The project’s creative content is a Swedish pop album which created through collaborative and independent work. Three single releases and one music video have been released and distributed through the course of the project on streaming platforms such as Spotify and YouTube. In addition to the making of the album I have chosen to create a model to use as a frame for potential recruitment instances of creative collaborations, improve role definition and develop a more accurate method to credit rights holder’s moral credentials as a contributor to an artistic work. The root cause of this model is that a music producer often finds themselves as a multicompetent keyperson in creative collaborations where the lines between different professions overlap. The model is inspired of the software developers job terminology and aims to break up umbrella concept roles such as “songwriter, producer and performer” to facilitate the recruiting process of creative collaborations within the crafting of songs. The terminologies inspired out of the software developer’s professions are back-end, front-end and full-stack.
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DeWitt, Martin Alan. "The Spectrum and Decays of Scalar Mesons in the Light-Front Quark Model." NCSU, 2008. http://www.lib.ncsu.edu/theses/available/etd-03282008-142316/.
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We use the light-front quark model to investigate the structure of the scalar mesons, mainly focusing on the three heavy isoscalar states f0(1370), f0(1500), and f0(1710). We comput the spectrum of scalar mesons by diagonalizing a relativized, QCD-inspired model Hamiltonian written in a basis of 25 simple harmonic oscillator states. The masses are then used to perform a mixing analysis which assumes that the heavy isoscalars are mixtures of quarkonia and the scalar glueball. The resulting quark-glue content is used along with the meson wave functions determined from the spectrum to compute the decay rates to pairs of pseudoscalar mesons (two pions, two kaons, two eta mesons). We find that when the glueball contributions to the decays are ignored, the results are in poor agreement with the available data. However, when we estimate the effect of including the glueball contributions in the decays, a solution can be found that matches the data quite well. In this solution, the f0(1710) is mostly glueball (78%) while the f0(1500) and f0(1370) are mostly mixtures of quarkonia. Additionally, in this solution the glueball contributions to kaon and eta final states are significant, while the contributions to the pion final state is negligible. This finding is in agreement with Chanowitz who uses chiral perturbation theory to show that the amplitude for a scalar glueball to decay to a quark-antiquark pair is proportional to the quark mass. This results in a suppression of the pion decay channel compared to the kaon and eta decay channels.
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Wan, Kwok-fai, and 尹國輝. "Beijing's united front policy toward Hong Kong: an application of Merilee Grindle's model." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2003. http://hub.hku.hk/bib/B31227922.
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Sun, Wenjun. "Front tracking algorithm for the Lighthill-Whitham-Richards model for a traffic network." Click to view the E-thesis via HKUTO, 2008. http://sunzi.lib.hku.hk/hkuto/record/B40687624.
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Terdalkar, Rahul J. "Direct numerical simulation of swirling flows using the front tracking method." Worcester, Mass. : Worcester Polytechnic Institute, 2007. http://www.wpi.edu/Pubs/ETD/Available/etd-122007-233351/.
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Piper, David. "A mathematical model of frost heave in granular materials." Thesis, University of Nottingham, 1987. http://eprints.nottingham.ac.uk/28821/.
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An initial review of the various theories of frost heave indicated that Miller's theory of secondary heave was the most convincing. The crucial area in this is the representation of the behaviour in the partially frozen region, known as the frozen fringe, which exists below the lowest ice lens. However, the computational difficulties of the associated mathematical model were likely to limit its application. A simpler quasi-static approach for a semi-infinite region had therefore been initiated, for a restricted range of conditions, by Holden. The work described in this thesis traces the development of the quasi-static approach and its application to the unidirectional freezing of a finite soil column. The resulting generalised model successfully predicts the freezing behaviour under a wide range of conditions. In particular, it is applicable to all overburden pressures, including zero. At low overburdens the frozen fringe disappears, but the final phase is nevertheless modelled to its ultimate equilibrium state. The predictions of the model agree with published experimental data from a number of investigators, and thus support the validity of Miller's theory. Parametric studies with the model have highlighted the importance of the hydraulic conductivity and the relationship between suction, temperature and ice content in the frozen fringe. Simulations are relatively insensitive to variations in thermal conductivity. The model has proved to be robust and stable and should form a sound basis for further studies. However, its full application will depend on the development of experimental techniques to determine the hydraulic conductivity in the frozen fringe.
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Yang, Bo. "Topology investigation of front end DC/DC converter for distributed power system." Diss., Virginia Tech, 2003. http://hdl.handle.net/10919/28982.
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With the fast advance in VLSI technology, smaller, more powerful digital system is available. It requires power supply with higher power density, lower profile and higher efficiency. PWM topologies have been widely used for this application. Unfortunately, hold up time requirement put huge penalties on the performance of these topologies. Also, high switching loss limited the power density achievable for these topologies.
Two techniques to deal with hold up time issue are discussed in this dissertation: range winding solution and asymmetric winding solution, the efficiency at normal operation point could be improved with these methods. To reduce secondary rectifier conduction loss, QSW synchronous rectifier is developed, which also helps to achieve ZVS for symmetrical half bridge converter.
Although with these methods, the efficiency of front end DC/DC converter could be improved, the excessive switching loss prohibited higher switching frequency. To achieve the targets, topologies with high switching frequency and high efficiency must be developed.
Three resonant topologies: SRC, PRC and SPRC, are been investigated for this application because of their fame of low switching loss. Unfortunately, to design with hold up requirement, none of them could provide significant improvements over PWM converter.
Although the negative outcome, the desired characteristic for front end application could be derived. Base on the desired characteristic, a thorough search is performed for three elements resonant tanks. LLC resonant topology is found to posses the desired characteristic. From comparison, LLC resonant converter could reduce the total loss by 40% at same switching frequency. With doubled switching frequency, efficiency of LLC resonant converter is still far better than PWM converters.
To design the power stage of LLC resonant converter, DC analysis is performed with two methods: simulation and fundamental component simplification. Magnetic design is also discussed. The proposed integrated magnetic structure could achieve smaller volume, higher efficiency and easy manufacture.
To make practical use of the topology, over load protection is a critical issue. Three methods to limit the stress under over load situation are discussed. With these methods, the converter could not only survive the over load condition, but also operate for long time under over load condition.
Next small signal characteristic of the converter is investigated in order to design the feedback control. For resonant converter, state space average method is no longer valid. Two methods are used to investigate the small signal characteristic of LLC resonant converter: simulation and extended describing function method. Compare with test results, both methods could provide satisfactory results. To achieve both breadth and depth, two methods are both used to reveal the myth. With this information, compensator for feedback control could be designed.
Test circuit of LLC resonant converter was developed for front end DC/DC application. With LLC topology, power density of 48W/in3 could be achieved compare with 13W/in3 for PWM converter.Ph. D.
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Götz, Sebastian, Thomas Kühn, Christian Piechnick, Georg Püschel, and Uwe Aßmann. "A Models@run.time Approach for Multi-objective Self-optimizing Software." Springer, 2014. https://tud.qucosa.de/id/qucosa%3A75372.
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This paper presents an approach to operate multi-objective self-optimizing software systems based on the models@run.time paradigm. In contrast to existing approaches, which are usually specific to a single or selected set of objectives (e.g., performance and/or reliability), the presented approach is generic in that it allows the software architect to model the relevant concerns of interest to self-optimization. At runtime, these models are interpreted and used to generate optimization problems. To evaluate the applicability of the approach, a scalability analysis is provided, showing the approach’s feasibility for at least two objectives.
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Van, Niekerk Cordi. "Building a model to improve front end project conceptualisation: introducing the Project Conceptualisation Canvas." Doctoral thesis, Faculty of Commerce, 2020. http://hdl.handle.net/11427/32368.
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Project management has seen significant growth which has been beneficial to academics and practitioners in the field alike. However, the alarming trend of project underperformance continues. This points to an apparent relevance gap in Project Management. One of the areas that has been highlighted as an important area for further study to improve this situation is project front end management. Using Design Science as research methodology, the knowledge contribution of this research is an artefact called, the Project Conceptualisation Canvas. The Project Conceptualisation Canvas represents a process to be followed to ensure that the conceptualisation phases of potential projects are adequately performed. The Project Conceptualisation Canvas was developed using as input the results of the systematic review of literature on the typical challenges that occur during project conceptualisation. The Project Conceptualisation Canvas was evaluated through two sets of focus groups which confirmed that it contributes towards the improvement of project conceptualisation practice. The relevance of the contribution of the Project Conceptualisation Canvas is that it will improve decision making during the project conceptualisation and selection process which will ultimately result into improved project delivery and reduced opportunity cost that results from underperforming projects.
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Mo, Yizhang. "The application of the light-front Tamm-Dancoff approximation to the massive Schwinger model /." The Ohio State University, 1992. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487780393268377.
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Wikström, Anders. "Yaw Rate and Lateral Acceleration Sensor Plausibilisation in an Active Front Steering Vehicle." Thesis, Linköping University, Department of Electrical Engineering, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-8027.
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Accurate measurements from sensors measuring the vehicle's lateral behavior are vital in todays vehicle dynamic control systems such as the Electronic Stability Program (ESP). This thesis concerns accurate plausibilisation of two of these sensors, namely the yaw rate sensor and the lateral acceleration sensor. The estimation is based on Kalman filtering and culminates in the use of a 2 degree-of-freedom nonlinear two-track model describing the vehicle lateral dynamics. The unknown and time-varying cornering stiffnesses are adapted while the unknown yaw moment of inertia is estimated. The Kalman filter transforms the measured signals into a sequence of residuals that are then investigated with the aid of various change detection methods such as the CuSum algorithm. An investigation into the area of adaptive thresholding has also been made.
The change detection methods investigated successfully detects faults in both the yaw rate and the lateral acceleration sensor. It it also shown that adaptive thresholding can be used to improve the diagnosis system. All of the results have been evaluated on-line in a prototype vehicle with real-time fault injection.
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Schellekens, Fons Jozef. "Fundamentals, accuracy and input parameters of frost heave prediction models." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/NQ26887.pdf.
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Schellekens, Fons Jozef Carleton University Dissertation Earth Sciences. "Fundamentals, accuracy and input parameters of frost heave prediction models." Ottawa, 1997.
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Fukamachi, Yasushi. "Instability of Density Fronts in Layer and Continuously Stratified Models." NSUWorks, 1992. http://nsuworks.nova.edu/occ_stuetd/64.
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The instability of density fronts is investigated as a possible generation mechanism of the small-scale, wave-like patterns observed along upwelling fronts and filaments. Solutions are obtained using three different models: a linearized 1½-layer model, a nonlinear 1½-layer model, and a linearized continuously stratified model confined to the surface layer of the ocean. The front is specified in two different ways: vertically oriented isopycnals along with slab-like current in the layer model, and nearly vertical isopycnals associated with vertical shear in the continuously stratified model. The prescribed state used for both the linearized and nonlinear models consists of either a uniform or zonally sheared current in a layer of constant thickness that is geostrophically balanced by the horizontal temperature gradient within the layer.
In the layer model, an analytical solution is obtained to the linearized system. When the background current is balanced by the horizontal temperature gradient alone, this solution is unconditionally unstable. Energetic analyses of numerical solutions for both uniform and zonally sheared, background currents indicate that frontal instability, which utilizes the available potential energy associated with the horizontal temperature gradient within the layer, is responsible for the growth of the unstable waves. Interestingly, the unstable waves have negative energy due to the presence of the non-positive definite terms in the definition of the wave energy. A nonlinear solution for a zonally sheared, initial current simulates the observed wave-like patterns.
In the continuously stratified model, the unstable waves have positive energy and are generated by baroclinic instability. For a uniform background current, they are essentially the ageostrophic extensions of the Eady's baroclinic waves. For a zonally sheared current, they resemble the observed wave-like patterns, suggesting that the observed features are generated by ageostrophic baroclinic instability.
Although there are some differences between solutions in the layer and continuously stratified models, the layer system including vertically oriented isopycnals provides a reasonable alternative of the continuously stratified system. Moreover, the difference in wave energetics between the layer and continuously stratified models is likely an artifact of the different model formulations.
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Smith, Colin Campbell. "Thaw induced settlement of pipelines in centrifuge model tests." Thesis, University of Cambridge, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.239788.
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Costa, Thiago Podadera. "Modelo paramétrico regional da corrente do Brasil na Bacia de Campos." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/21/21132/tde-19042012-153140/.
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Um modelo paramétrico regional tridimensional da Corrente do Brasil (CB) foi construído com o objetivo de investigar se o meandramento frontal da CB domina a variabilidade subinercial na Bacia de Campos. A parametrização da CB normal à costa seguiu a formulação proposta por Schmidt et al. [2007]. Os parâmetros da CB foram estimados a partir dos perfis de velocidade quase-sinóticos durante a amostragem do cruzeiro OCEANO SUDESTE II (OCSEII) da Marinha do Brasil. A frente térmica costeira (FTC), facilmente detectado na superfície do mar por imagens de satélite, é tida como a fronteira costeira do CB com velocidades desprezíveis. A FTC padrão é, então, inferida pelo método do gradiente máximo em uma data escolhida. Com a localização da FTC, várias radiais são projetadas normalmente à frente e os perfis de velocidades da CB são ajustados a estas radiais. O próximo passo é interpolar objetivamente o campo de velocidade para obter uma CB tridimensional. A variabilidade espacial da CB neste mapa é, portanto, unicamente devido à arqueamento da velocidade/ FTC, e os padrões de velocidade são devidos apenas ao meandramento frontal. Estes foram identificados nas séries temporais das FTC e o modelo foi computado para dois eventos separados no inverno de 2007 e comparados com os dados de ADCPs da PETROBRAS montados em quatro plataformas de petróleo. A comparação foi feita usando compósitos semanais e médias para isolar movimentos de mesoescala. Isso mostra que há um acordo muito favorável entre o modelo e as medições de velocidade de mar aberto em ambas as magnitudes e direções. Este assegura que os meandros frontais, ou mais especificamente, o meandro de São Tomé domina a variabilidade subinercial ao longo do talude continental e do platô de São Paulo. A única exceção é para o ADCP montado sobre uma plataforma de petróleo em plataforma continental. O modelado e as observações in situ discordam e indicam que outros fenômenos, tais como ondas de plataforma, devem ser contabilizados na parte costeiraA regional three-dimensional parametric model of the Brazil Current (BC) was built with the goal of investigating whether or not the BC frontal meandering dominates the subinercial current variability in the Campos Basin. The BC cross-stream parametrization followed the formulation proposed by Schmidt et al. [2007]. The BC parameters were estimated from quasi-synoptic velocity profiling sampled during the Brazilian Navy cruise OCEANO SUDESTE II (OCSEII). The surface inshore thermal front (ITF),easily detected in sea surface temperature satellite images, is taken as the inshore border of the BC jet with negligible velocities. The ITF spatial pattern is then inferred by the maximum gradient method on a chosen date or period. With the ITF location, several BC cross-strem profiles are projected normally to it. The next step is to objectively interpolate the velocity field to obtain a three-dimensional BC. The spatial variability of the BC in this map is therefore solely due to the arching of the velocity/ITF front, and therefore, the velocity patterns are due to frontal meandering only. Meandering events were identified in the IFT time series, the model computed the BC frontal patterns for two separate events in the winter of 2007 and compared with PETROBRAS\' ADCP records mounted on four oil rigs. The comparison was done using weekly composites and averages to isolate mesoscale motions. It shows that there is a very favorable agreement between between the model and the open sea velocity measurements in both magnitude and direction. This reassures that the frontal meandering, or more specifically, the S~ao Tom´e Meander formation dominates the subinertial variability over the continental slope and the S~ao Paulo Plateau. The only exception is for the ADCP mounted on an oil rig on the continental shelf. The modeled and in situ observations disagree and indicate that other phenomena, such as shelf waves, should be accounted in the coastal ocean in addition to the BC meandering.
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Pimsamarn, Kulapant. "Electromagnetic scattering model for saline ice covered with frost flowers." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/17443.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1997.Includes bibliographical references (leaves 83-87).
by Kulapant Pimsamarn.
M.Eng.
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Yetter, Joseph A. "The nature of the propagation of sea breeze fronts in Central California." Monterey, California : Naval Postgraduate School, 1990. http://handle.dtic.mil/100.2/ADA238635.
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Thesis (M.S. in Meteorology and Oceanography)--Naval Postgraduate School, September 1990.Thesis Advisor(s): Shaw, William J. Second Reader: Durkee, Philip A. "September 1990." Description based on title screen as viewed on December 15, 2009. DTIC Identifier(s): Fronts (Meteorology), Atmosphere Models, Wave Propagation, LASBEX (Land Sea Breeze Experiment), Meteorological Data, Circulation, Directional, Atmospheric Motion. Author(s) subject terms: LASBEX, Lidar, Sodar. Includes bibliographical references (p. 64-65). Also available in print.
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Egorova, Vera. "Finite Difference Methods for nonlinear American Option Pricing models: Numerical Analysis and Computing." Doctoral thesis, Universitat Politècnica de València, 2016. http://hdl.handle.net/10251/68501.
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[EN] The present PhD thesis is focused on numerical analysis and computing of finite difference schemes for several relevant option pricing models that generalize the Black-Scholes model. A careful analysis of desirable properties for the numerical solutions of option pricing models as the positivity, stability and consistency, is provided.
In order to handle the free boundary that arises in American option pricing problems, various transformation techniques based on front-fixing method are applied and studied. Special attention is paid to multi-asset option pricing, such as exchange or spread option. Appropriate transformation allows eliminating of the cross derivative term. Transformation techniques of partial differential equations to remove convection and reaction terms are studied in order to simplify the models and avoid possible troubles of stability.
This thesis consists of six chapters. The first chapter is an introduction containing definitions of option and related terms and derivation of the Black-Scholes equation as well as general aspects of theory of finite difference schemes, including preliminaries on numerical analysis.
Chapter 2 is devoted to solve linear Black-Scholes model for American put and call options. A Landau transformation and a new front-fixing transformation are applied to the free boundary value problem. It leads to non-linear partial differential equation (PDE) in a fixed domain. Stable and consistent explicit numerical schemes are proposed preserving positivity and monotonicity of the solution in accordance with the behaviour of the exact solution.
Efficiency of the front-fixing method demonstrated in Chapter 2 has motivated us to apply the method to some more complicated nonlinear models. A new change of variables resulting in a time dependent boundary instead of fixed one, is applied to nonlinear Black-Scholes model for American options, such as Barles and Soner and Risk Adjusted Pricing models.
Chapter 4 provides a new alternative approach for solving American option pricing problem based on rationality of investor. There exists an intensity function that can be reduced in the simplest case to penalty approach.
Chapter 5 deals with multi-asset option pricing. Appropriate transformation allows eliminating of the cross derivative term avoiding computational drawbacks and possible troubles of stability.
Concluding remarks are given in Chapter 6. All the considered models and numerical methods are accompanied by several examples and simulations. The convergence rate is computed confirming the theoretical study of consistency. Stability conditions are tested by numerical examples. Results are compared with known relevant methods in the literature showing efficiency of the proposed methods.[ES] La presente tesis doctoral se centra en la construcción de esquemas en diferencias finitas y el análisis numérico de relevantes modelos de valoración de opciones que generalizan el modelo de Black-Scholes. Se proporciona un análisis cuidadoso de las propiedades de las soluciones numéricas tales como la positividad, la estabilidad y la consistencia. Con el fin de manejar la frontera libre que surge en los problemas de valoración de opciones Americanas, se aplican y se estudian diversas técnicas de transformación basadas en el método de fijación de las fronteras (front-fixing). Se presta especial atención a la valoración de opciones de múltiples activos, como son las opciones ''exchange'' y ''spread''. Esta tesis se compone de seis capítulos. El primer capítulo es una introducción que contiene las definiciones de opción y términos relacionados y la derivación de la ecuación de Black-Scholes, así como aspectos generales de la teoría de los esquemas en diferencias finitas, incluyendo preliminares de análisis numérico. El capítulo 2 está dedicado a resolver el modelo lineal de Black-Scholes para opciones Americanas put y call. Para fijar las fronteras del problema de frontera libre se aplican transformaciones como la de Landau y un nuevo cambio de variable propuesto. La eficiencia del método front-fixing mostrada en el capítulo 2 ha motivado el estudio de su aplicación a algunos modelos no lineales más complicados. En particular, se propone un cambio de variables que lleva a una nueva frontera dependiente del tiempo en lugar de una fija. Este cambio se aplica a modelos no lineales de Black-Scholes para opciones Americanas, como son el de Barles y Soner y el modelo RAPM (Risk Adjusted Pricing Methodology). El capítulo 4 ofrece una nueva técnica para la resolución de problemas de valoración de opciones Americanas basada en la racionalidad de los inversores. Aparece una función de la intensidad que se puede reducir en el caso más simple a la técnica de penalización (penalty method). Este enfoque tiene en cuenta el posible comportamiento irracional de los inversores. En la sección 4.2 se aplica esta técnica al modelo de cambio de regímenes lo que lleva a un nuevo modelo que tiene en cuenta el posible ejercicio irracional, así como varios estados del mercado. El enfoque del parámetro de racionalidad junto con una transformación logarítmica permiten construir un esquema numérico eficiente sin aplicar el método front-fixing o la conocida formulación de LCP (Linear Complementarity Problem). El capítulo 5 se dedica a la valoración de opciones de activos múltiples. Una transformación apropiada permite la eliminación del término de derivadas cruzadas evitando inconvenientes computacionales y posibles problemas de estabilidad. Las conclusiones se muestran en el capítulo 6. Se pone en relieve varios aspectos de la presente tesis. Todos los modelos considerados y los métodos numéricos van acompañados de varios ejemplos y simulaciones. Se estudia la convergencia numérica que confirma el estudio teórico de la consistencia. Las condiciones de estabilidad son corroboradas con ejemplos numéricos. Los resultados se comparan con métodos relevantes de la bibliografía mostrando la eficiencia de los métodos propuestos.
[CAT] La present tesi doctoral se centra en la construcció d'esquemes en diferències finites i l'anàlisi numèrica de rellevants models de valoració d'opcions que generalitzen el model de Black-Scholes. Es proporciona una anàlisi cuidadosa de les propietats de les solucions numèri-ques com ara la positivitat, l'estabilitat i la consistència. A fi de manejar la frontera lliure que sorgix en els problemes de valoració d'opcions Americanes, s'apliquen i s'estudien diverses tècniques de transformació basades en el mètode de fixació de les fronteres (front-fixing). Es presta especial atenció a la valoració d'opcions de múltiples actius, com són les opcions ''exchange'' i ''spread''. Esta tesi es compon de sis capítols. El primer capítol és una introducció que conté les definicions d'opció i termes relacionats i la derivació de l'equació de Black-Scholes, així com aspectes generals de la teoria dels esquemes en diferències finites, incloent aspectes preliminars d'anàlisi numèrica. El 2n capítol està dedicat a resoldre el model lineal de Black-Scholes per a opcions Americanes ''put'' i ''call''. Per a fixar les fronteres del problema de frontera lliure s'apliquen transformacions com la de Landau i s'ha proposat un nou canvi de variable proposat. Açò porta a una equació diferencial en derivades parcials no lineal en un domini fix. L'eficiència del mètode front-fixing mostrada en el 2n capítol ha motivat l'estudi de la seua aplicació a alguns models no lineals més complicats. En particular, es proposa un canvi de variables que porta a una nova frontera dependent del temps en compte d'una fixa. Este canvi s'aplica a models no lineals de Black-Scholes per a opcions Americanes, com són el de Barles i Soner i el model RAPM (Risk Adjusted Pricing Methodology). El 4t capítol oferix una nova tècnica per a la resolució de problemes de valoració d'opcions Americanes basada en la racionalitat dels inversors. Apareix una funció de la intensitat que es pot reduir en el cas més simple a la tècnica de penalització (penal method) . Este enfocament té en compte el possible comportament irracional dels inversors. En la secció 4.2 s'aplica esta tècnica al model de canvi de règims el que porta a un nou model que té en compte el possible exercici irracional, així com diversos estats del mercat. L'enfocament del paràmetre de racionalitat junt amb una transformació logarítmica permeten construir un esquema numèric eficient sense aplicar el mètode front-fixing o la coneguda formulació de LCP (Linear Complementarity Problem). El 5é capítol es dedica a la valoració d'opcions d'actius múltiples. Una transformació apropiada permet l'eliminació del terme de derivades mixtes evitant inconvenients computacionals i possibles problemes d' estabilitat. Les conclusions es mostren al 6é capítol. Es posa en relleu diversos aspectes de la present tesi. Tots els models considerats i els mètodes numèrics van acompanyats de diversos exemples i simulacions. S'estu-dia la convergència numèrica que confirma l'estudi teòric de la consistència. Les condicions d'estabilitat són corroborades amb exemples numèrics. Els resultats es comparen amb mètodes rellevants de la bibliografia mostrant l'eficiència dels mètodes proposats.
Egorova, V. (2016). Finite Difference Methods for nonlinear American Option Pricing models: Numerical Analysis and Computing [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/68501
TESIS
Premiado
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Cohen, Jed Jacob. "The Effect of Mountain Pine Beetle Induced Tree Mortality on Home Values in the Colorado Front Range." Thesis, Virginia Tech, 2013. http://hdl.handle.net/10919/23170.
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Throughout the past decade American pine forests have experienced an epidemic of Mountain Pine Beetle (MPB) induced tree mortality. This thesis estimates the losses to home values caused by deteriorating forest quality in the Front Range Counties of Larimer and Boulder Colorado. We employ a repeat sales model that allows for region specific price indices, and non-linear age-related depreciation in home values. We use the time-invariant existence of pine forest near a home to overcome shortcomings in the measurement of MPB damage. We infer from temporal changes in the marginal "effect of pine trees near a home the approximate MPB "effect . We label this strategy the translating commodity approach. Using this strategy we are able to show that diminished forest quality causes forests to become a dis-amenity that negatively affects nearby home values. The total loss in 2011 home values due to their proximity to dying forest is estimated to be $137 million for all the homes in our sample. Such substantial losses may justify a forest management policy shift in order to better mitigate the risk of future MPB outbreaks.Master of Science
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Tondu, Yohann. "Simulation of the Paris 1910 flood with a lumped hydrological model: the influence of frozen soil." Thesis, KTH, Vattendragsteknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-96310.
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In 1910, Paris experienced its biggest flood in the 20th century. In 2010, for the anniversary of this event – supposed to happen every 100 years ! – the flood prediction model that is now used on the Seine basin was tested on its simulation,… and failed to reproduce the observed flood volume. This paper will try to explain, and correct, such disappointing results. Many hypotheses have been tested and based on their results, it has been decided to develop a frost module in order to assess the influence of this phenomenon – that is not taken into account by the lumped hydrological model that is used – on the flood formation. A soil temperature model using air temperature as input data was also designed because soil temperature data were not available in 1910. The addition of the frost module did not, however, bring many improvements to the 1910 flood simulation because frost is a too rare phenomenon on the Seine basin for the module to be correctly calibrated. However, new perspectives are presented to continue the research on this phenomenon.
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Essien, Mmekutmfon Sunday. "A multiobjective optimization model for optimal placement of solar collectors." Diss., University of Pretoria, 2012. http://hdl.handle.net/2263/30954.
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The aim and objective of this research is to formulate and solve a multi-objective optimization problem
for the optimal placement of multiple rows and multiple columns of fixed flat-plate solar collectors
in a field. This is to maximize energy collected from the solar collectors and minimize the
investment in terms of the field and collector cost. The resulting multi-objective optimization problem
will be solved using genetic algorithm techniques.
It is necessary to consider multiple columns of collectors as this can result in obtaining higher amounts
of energy from these collectors when costs and maintenance or replacement of damaged parts are
concerned. The formulation of such a problem is dependent on several factors, which include shading
of collectors, inclination of collectors, distance between the collectors, latitude of location and the
global solar radiation (direct beam and diffuse components). This leads to a multi-objective optimization
problem. These kind of problems arise often in nature and can be difficult to solve. However
the use of evolutionary algorithm techniques has proven effective in solving these kind of problems.
Optimizing the distance between the collector rows, the distance between the collector columns and
the collector inclination angle, can increase the amount of energy collected from a field of solar collectors
thereby maximizing profit and improving return on investment.
In this research, the multi-objective optimization problem is solved using two optimization approaches
based on genetic algorithms. The first approach is the weighted sum approach where the
multi-objective problem is simplified into a single objective optimization problem while the second
approach is finding the Pareto front.Dissertation (MEng)--University of Pretoria, 2012.
Electrical, Electronic and Computer Engineering
MEng
Unrestricted
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Eftelioglu, Mustafa. "Numerical model for determining the wetting front in a clay layer of a leaking composite barrier." Morgantown, W. Va. : [West Virginia University Libraries], 2001. http://etd.wvu.edu/templates/showETD.cfm?recnum=2067.
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Thesis (Ph. D.)--West Virginia University, 2001.Title from document title page. Document formatted into pages; contains ix, 160 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 102-107).
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Griette, Quentin. "Mathematical and numerical analysis of propagation models arising in evolutionary epidemiology." Thesis, Montpellier, 2017. http://www.theses.fr/2017MONTS051/document.
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Cette thèse porte sur différents modèles de propagation en épidémiologie évolutive. L'objectif est d'en faire une analyse mathématique rigoureuse puis d'en tirer des enseignements biologiques. Dans un premier temps nous envisageons le cas d'une population d'hôtes répartis de manière homogène dans un espace linéaire, dans laquelle se propage un pathogène pouvant muter entre deux phénotypes plus ou moins virulents. Ce phénomène de mutation est à l'origine d'une interaction entre les dynamiques évolutive et épidémiologique du pathogène. Nous étudions la vitesse de propagation de l'épidémie et l'existence de fronts progressifs, ainsi que l'influence sur la vitesse de différents facteurs biologiques, comme des effets stochastiques liés à la taille de la population d'hôtes (explorations numériques). Dans un deuxième temps nous envisageons une hétérogénéité spatiale périodique dans la population d'hôtes, et l'existence de fronts pulsatoires pour le système de réaction-diffusion (non-coopératif) associé. Enfin nous considérons un pathogène pouvant muter vers un grand nombre de phénotypes différents et étudions l'existence de fronts potentiellement singuliers, modélisant ainsi une concentration sur un trait optimalIn this thesis we consider several models of propagation arising in evolutionary epidemiology. We aim at performing a rigorous mathematical analysis leading to new biological insights. At first we investigate the spread of an epidemic in a population of homogeneously distributed hosts on a straight line. An underlying mutation process can shift the virulence of the pathogen between two values, causing an interaction between epidemiology and evolution. We study the propagation speed of the epidemic and the influence of some biologically relevant quantities, like the effects of stochasticity caused by the hosts' finite population size (numerical explorations), on this speed. In a second part we take into account a periodic heterogeneity in the hosts' population and study the propagation speed and the existence of pulsating fronts for the associated (non-cooperative) reaction-diffusion system. Finally, we consider a model in which the pathogen is allowed to shift between a large number of different phenotypes, and construct possibly singular traveling waves for the associated nonlocal equation, thus modelling concentration on an optimal trait
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Buss, Carla de Oliveira. "Modelo de sistematização e integração da inteligência de mercado ao front-end do processo de desenvolvimento de produtos." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2008. http://hdl.handle.net/10183/14862.
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A integração da inteligência de mercado e a estruturação eficaz das fases iniciais (também conhecidas como front-end) do processo de desenvolvimento de novos produtos são dois dos mais importantes e difíceis desafios que inovadores enfrentam. Esta tese concentra-se na ligação entre estes dois aspectos, oferecendo um modelo conceitual para a sistematização e integração da inteligência de mercado nas atividades do front-end. O modelo, intitulado MISIPro (Market Intelligence Sistematization e Integration Process – Processo de sistematização e integração da inteligência de mercado), considera dois tipos diferentes de atividades que ocorrem no front-end: a) atividades de processamento de informações de mercado; e b) atividades de desenvolvimento de produtos. Essas atividades são então definidas, estruturadas e integradas. O modelo foi desenvolvido com base numa revisão da literatura sobre desenvolvimento de produtos, orientação de mercado e gestão do conhecimento e em 5 estudos de caso em empresas no Brasil e nos Estados Unidos. Como contribuição teórica, esta tese apresenta uma integração de conceitos importantes provenientes de diferentes perspectivas e áreas de conhecimento e uma nova abordagem e estrutura para a concepção do conceito. Para os profissionais, o modelo oferece uma ferramenta útil para a estruturação das atividades do front-end e integração das informações de mercado no processo de desenvolvimento de produtos.Integrating market intelligence and effective structuring of the planning stages (also known as front-end) of new product development (NPD) process are two of the most important and difficult challenges facing innovators. This dissertation focuses on the link between these two elements, offering a conceptual model for the systematization and integration of market intelligence into the frontend activities. The model, entitled MISIPro (Market Intelligence Systematization and Integration Process), considers two different types of activities that take place in the front-end: a) market information processing activities; and b) product development activities. These activities are herein defined, structure and mutually integrated. The model was developed based on a review of the literature about product development, market orientation and knowledge management, and 5 case studies in Brazilian and U.S. companies. From a theoretical perspective, this dissertation offers an integration of the important concepts from different perspectives and areas of knowledge and a new approach and structure for the concept design. For practitioners, the model offers a useful tool for structuring the front-end activities and integrating market intelligence into the NPD process.
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Karsten, Richard H. "Nonlinear effects in two-layer, frontal-geostrophic models of surface ocean fronts." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape15/PQDD_0027/NQ34786.pdf.
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Sabeh, Darwiche. "Adapting the Green and Ampt model to account for air compression and counterflow." [Tampa, Fla.] : University of South Florida, 2004. http://purl.fcla.edu/fcla/etd/SFE0000493.
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Rodrigues, Thaisa. "Proposta de modelo cognitivo para estruturar atividades-chave do planejamento estratégico do produto no Fuzzy Front-End." Universidade Tecnológica Federal do Paraná, 2015. http://repositorio.utfpr.edu.br/jspui/handle/1/1489.
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CAPESO Planejamento Estratégico de Produto (PEP) faz parte da macro-fase inicial do Processo de Desenvolvimento de produtos (PDP) conhecida como Fuzzy Front-End (FFE), que exige alto esforço cognitivo de gestores e profissionais, uma vez que o grande número de atividades, bem como o alto nível de interdependência entre elas e também as peculiaridades de cada projeto faz com que as atividades estruturantes sejam um problema complexo. A fim de estruturar as principais atividades em PEP no FFE, propôs-se um modelo cognitivo usando o Strategic Options Development and Analysis (SODA). O modelo proposto foi aplicado em quatro indústrias brasileiras, duas do setor de alimentos e duas do setor de móveis. O estudo revelou que as atividades no FFE se relacionam entre si de uma forma hierárquica, com um alto nível de complexidade e algumas atividades se comportam como estratégias, como opções, ou ainda como objetivos ou metas. As atividades encontradas no setor de alimentos são parecidas com as encontradas no setor de móveis, mas possuem algumas diferenças devido a peculiaridades de cada setor. Recomenda-se o modelo cognitivo para apoiar os gestores e profissionais na estruturação das atividades de PEP.
Strategic product planning (SPP) for new product development (NPD) in the fuzzy front end (FFE) requires high cognitive effort from managers and practitioners, since the large number of Activities as well as the high level of interdependence Among Them And Also the peculiarities of each project make the structuring Activities the messy problem. In order to structure key Activities on SPP in the FFE, we propose the cognitive model using the Strategic Options Development and Analysis (SODA) method. The Proposed model was applied in two Brazilian industries from the food sector. This study revealed that the activities in the FFE report to each other in a hierarchical mannered, with a high level of complexity, and some Activities behave the other options the strategies and the other goals. The activities found in the food sector are similar to those found in the mobile sector, but have some differences due to peculiarities of each sector. We recommend the cognitive model to assist managers and practitioners structuring Activities on SPP.
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Freydier, Perrine. "Dynamique interne au front d'écoulements à surface libre. Application aux laves torrentielles." Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAU010/document.
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Le modèle de couche mince intégré sur l'épaisseur, Saint-Venant, utilisé classiquement pour simuler la propagation de laves torrentielles et coulées boueuses, repose sur plusieurs approximations concernant la forme des profils de vitesse en zones non-uniformes. Il est pourtant nécessaire d'utiliser ce type de modélisation, comme outil d'aide à la gestion des risques liés aux laves torrentielles. Nous proposons d'éprouver ses hypothèses, en observant une zone fortement non-uniforme, le front de coulées à surface libre et le champ de vitesse à l'intérieur de cette zone.En améliorant notre connaissance de l'évolution de la forme des profils de vitesse (de la dynamique interne) au front de coulées, nous cherchons à améliorer les modèles de couche mince. Cette thèse porte donc sur l'étude de la dynamique interne au front d'écoulements à surface libre de fluides newtoniens et viscoplastiques.Nous avons utilisé le dispositif du canal à fond mobile qui permet de générer des coulées stationnaires dans le référentiel de l'observateur au moyen d'un fond mobile remontant vers l'amont. Nous avons réalisé un travail technique sur ce canal et sur l'analyse des images pour pouvoir mesurer les champs de vitesse à haute résolution spatiale aux fronts de coulées à surface libre de fluides viscoplastiques. L'étude des fluides newtoniens a aussi été réalisée afin de valider les modèles et éprouver le dispositif expérimental.Nous avons comparé les résultats expérimentaux aux solutions théoriques de deux modèles de couche mince adaptés à la rhéologie de Herschel-Bulkley : le modèle classique de la lubrification, à la base du modèle de Saint-Venant et un modèle consistant à l'ordre 1 développé dans cette thèse. Le modèle consistant d'ordre 1 est la somme du modèle à l'ordre 0 (la lubrification) et de termes correctifs qui proviennent des contraintes normales et des termes d'inertie. Dans le cadre de notre configuration du fond mobile remontant vers l'amont, il est possible de déduire la forme du front en cherchant une solution de type onde progressive, sans passer par un modèle intégré dans l'épaisseur.Pour les fluides viscoplastiques, la structure classique du profil de vitesse, avec une zone cisaillée surmontée d'un plug non cisaillé est bien reconnaissable sur nos profils de vitesse en zone uniforme, et en zone faiblement variée. Mais à l'approche du front, cependant, la vitesse de surface augmente, les profils de vitesse expérimentaux deviennent cisaillés sur toute l'épaisseur, conduisant à la disparition du plug à proximité de la ligne de front.Le modèle de lubrification prédit l’existence d'un plug dans le front jusqu'à la ligne de contact, ce qui n'est pas observé expérimentalement. La vitesse de surface du modèle de lubrification augmente à l'approche du front, mais est largement sous-estimée par rapport à la vitesse de surface mesurée. Les vitesses de surface prédites par le modèle d'ordre 1 augmentent plus drastiquement au front, en meilleur accord avec les mesures que le modèle de lubrification. Pour certaines configurations expérimentales l'accord est même très bon. Remarquablement, le cisaillement des profils de vitesse à l'approche du front, observé expérimentalement, est aussi prédit par le modèle d'ordre 1.Les profils de vitesse présentent donc une évolution au front de coulées viscoplastiques en contradiction avec les hypothèses du modèle de Saint-Venant. Le modèle consistant d'ordre 1 permet d'améliorer les prédictions. Un modèle intégré dans l'épaisseur de type Saint-Venant basé sur les développements consistants d'ordre 1 est alors calculé, car il constitue l'étape nécessaire avant d'être intégré dans un outil de simulation opérationnelA depth-averaged model based on the thin-layer assumption, called Saint-Venant (Shallow-Water), is classically used to simulate the propagation and the spreading of debris and mud flows. It is based on several approximations concerning the shape of the velocity profile in non-uniform zones. We propose to test these hypotheses, examining a strongly non-uniform zone, the front of free-surface viscoplastic flows and the velocity field within this zone. By improving our knowledge about the internal dynamics in the front zone, we seek to improve the thin-layer models. This thesis therefore focuses on the study of the internal dynamics within the front of viscoplatic free-surface flows.We used the moving conveyor belt to generate stationary flows. We carried out a technical work on this set-up, and specific analysis of images obtained from the high-speed camera, in order to be able to measure velocity fields with a high resolution. The study of a Newtonian fluid was also carried out in order to validate the lubrication model and the experimental device.We compared experimental results to theoretical solutions of two thin-layer models taking into account the Herschel-Bulkley rheology: the classical model of lubrication, which is at the base of Saint-Venant model, and a consistent first-order model specifically developed in this thesis.The first-order model is equal to the zero-order model (lubrication), plus corrective terms derived from the normal stresses and inertia terms.In this study, for the purpose of comparison with our experimental results, we are interested in travelling-wave solutions. We are able to solve the shape of the front without using a depth-averaged model.Far from the front, experimental velocity profiles clearly display the characteristic 2-layer structure predicted by the lubrication solution, with constant values close to the free-surface (plug) and a sheared layer underneath. Closer to surge tip, the shape of experimental longitudinal velocity profilesthen begins to differ from the theoretical prediction. The 2-layer structure tends to disappear, and the profiles display shear across the whole depth ofthe flow. In this tip region, surface velocity also appears to increase faster than its theoretical counterpart. Surface velocity predicted by the first-order model increase more drastically in the tip region, in better agreement with the measurements than the lubrication model. The first-order model predicts a sheared velocity profile when approaching the front, as observed experimentally.The consistent first-order model then provides better predictions about internal dynamics than lubrication model. A depth-integrated model like Saint-Venant, based on consistent first-order developments is then calculated, as a first step before being integrated into an operational simulation tool
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Kariyannavar, Kiran. "Connecting the human body - Models, Connections and Competition." Thesis, Linköpings universitet, Elektroniksystem, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-78009.
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Capacitive communication using human body as a electrical channel has attracted much attention in the area of personal area networks (PANs) since its introduction by Zimmerman in 1995. The reason being that the personal information and communication appliances are becoming an integral part of our daily lives. The advancement in technology is also helping a great deal in making them interesting,useful and very much affordable. If we interconnect these body-based devices with capacitive communication approach in a manner appropriate to the power, size, cost and functionality, it lessens the burden of supporting a communication channel by existing wired and wireless technologies. More than that, using body as physical communication channel for a PAN device compared to traditional radio transmission seems to have a lot of inherent advantages in terms of power and security etc. But still a lot of feasibility and reliability issues have to be addressed before it is ready for prime time. This promising technology is recently sub-classified into body area networks (BAN) and is currently under discussion in the IEEE 802.15.6 Task Group for addressing the technical requirements to unleash its full potential for BANs. This could play a part in Ericsson's envision of 50 billion connections by 2020. This thesis work is part of the main project to investigate the models, interface and derive requirements on the analog-front-end (AFE) required for the system. Also to suggest a first order model of the AFE that suits this communication system.In this thesis work the human body is modeled along with interfaces and transceiver to reflect the true condition of the system functioning. Various requirements like sensitivity, dynamic range, noise figure and signal-to-noise ratio (SNR) requirements are derived based on the system model. An AFE model based on discrete components is simulated, which was later used for proof of concept. Also a first order AFE model is developed based on the requirements derived. The AFE model is simulated under the assumed interference and noise conditions. The first order requirements for the submodules of the AFE are also derived. Future work and challenges are discussed.