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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Caracterização da relaxação por compressão de borracha acrílica irradiada. / Compression relaxation characterization of irradiated acrylic rubber.

Santos, Demetrio Jackson dos 11 February 2011 (has links)
Este trabalho tem como objetivo investigar a redução da relaxação por compressão de borracha acrílica modificada (ACM) irradiada por feixe de elétrons, através da caracterização de seu comportamento mecânico e de sua estrutura molecular. O material, nas condições original e irradiado, foi inicialmente submetido a ensaios uniaxiais de tração e espectroscopia por infravermelho com o objetivo de verificar a influência da irradiação EB em seu comportamento, eliminando a possibilidade de degradação do material, permitindo a continuidade dos estudos. Definidas as doses, novos corpos de prova foram irradiados e submetidos a ensaios uniaxiais, equibiaxiais de tensão e cisalhamento puro, gerando resultados que foram aplicados na simulação pelo método de elementos finitos, utilizando o modelo de comportamento elástico não-linear de Ogden, para predizer o comportamento do material em condições de compressão. Confirmado o aumento da tensão por compressão para mesmas deformações, com o aumento da dose de radiação, análises termogravimétricas e dinâmicas mecânicas foram realizadas para possibilitar o entendimento do fenômeno. Na fase final do trabalho ensaios de relaxação por compressão foram realizados, em diferentes níveis de deformação e temperatura, apresentando a redução da relaxação por compressão gerada pela radiação EB e quantificando tal influência combinada com outros fatores, através da aplicação dos resultados no método de Planejamento Fatorial 2k. / The aim of this work is to investigate the compression stress relaxation (CSR) decrease of modified acrylic rubber, irradiated by electron beam, through its mechanical behavior and molecular structure characterization. Uniaxial tensile test and infrared spectroscopy were carried out, on original and irradiated material conditions, to verify the influence of EB irradiation on ACM, and to eliminate the possibility of degradation caused by EB radiation. After to define the radiation doses, new ACM specimens were irradiated. Uniaxial, equibiaxial and planar shear tests generated experimental data, which were applied to simulate the non linear elastic behavior of the material, through finite elements method, using the Ogden Model. Confirmed the compression stress increase at same deformation level, caused by increasing of radiation dose, thermogravimetric and dynamic mechanical analysis were carried out in order to make possible to understand the behavior changes. In the final part of this work, compression stress relaxation experiments were carried out, at two deformation and temperature levels, with the purpose to validate the compression stress relaxation decrease caused by EB radiation, and to quantify such influence combined with other factors. The CSR decrease combined with other influence variables were studied through use of factorial design.
12

Caracterização da relaxação por compressão de borracha acrílica irradiada. / Compression relaxation characterization of irradiated acrylic rubber.

Demetrio Jackson dos Santos 11 February 2011 (has links)
Este trabalho tem como objetivo investigar a redução da relaxação por compressão de borracha acrílica modificada (ACM) irradiada por feixe de elétrons, através da caracterização de seu comportamento mecânico e de sua estrutura molecular. O material, nas condições original e irradiado, foi inicialmente submetido a ensaios uniaxiais de tração e espectroscopia por infravermelho com o objetivo de verificar a influência da irradiação EB em seu comportamento, eliminando a possibilidade de degradação do material, permitindo a continuidade dos estudos. Definidas as doses, novos corpos de prova foram irradiados e submetidos a ensaios uniaxiais, equibiaxiais de tensão e cisalhamento puro, gerando resultados que foram aplicados na simulação pelo método de elementos finitos, utilizando o modelo de comportamento elástico não-linear de Ogden, para predizer o comportamento do material em condições de compressão. Confirmado o aumento da tensão por compressão para mesmas deformações, com o aumento da dose de radiação, análises termogravimétricas e dinâmicas mecânicas foram realizadas para possibilitar o entendimento do fenômeno. Na fase final do trabalho ensaios de relaxação por compressão foram realizados, em diferentes níveis de deformação e temperatura, apresentando a redução da relaxação por compressão gerada pela radiação EB e quantificando tal influência combinada com outros fatores, através da aplicação dos resultados no método de Planejamento Fatorial 2k. / The aim of this work is to investigate the compression stress relaxation (CSR) decrease of modified acrylic rubber, irradiated by electron beam, through its mechanical behavior and molecular structure characterization. Uniaxial tensile test and infrared spectroscopy were carried out, on original and irradiated material conditions, to verify the influence of EB irradiation on ACM, and to eliminate the possibility of degradation caused by EB radiation. After to define the radiation doses, new ACM specimens were irradiated. Uniaxial, equibiaxial and planar shear tests generated experimental data, which were applied to simulate the non linear elastic behavior of the material, through finite elements method, using the Ogden Model. Confirmed the compression stress increase at same deformation level, caused by increasing of radiation dose, thermogravimetric and dynamic mechanical analysis were carried out in order to make possible to understand the behavior changes. In the final part of this work, compression stress relaxation experiments were carried out, at two deformation and temperature levels, with the purpose to validate the compression stress relaxation decrease caused by EB radiation, and to quantify such influence combined with other factors. The CSR decrease combined with other influence variables were studied through use of factorial design.
13

Uma análise cienciométrica das subáreas da ciência da computação / A scientometric analysis of computer science subfields

Braga, Adriano Honorato 15 October 2013 (has links)
Submitted by Erika Demachki (erikademachki@gmail.com) on 2014-12-10T13:29:38Z No. of bitstreams: 1 Dissertação - Adriano Honorato Braga - 2013.pdf: 1269065 bytes, checksum: 31a4446602e6fc177149b700de63b216 (MD5) / Rejected by Erika Demachki (erikademachki@gmail.com), reason: on 2014-12-10T13:30:49Z (GMT) / Submitted by Erika Demachki (erikademachki@gmail.com) on 2014-12-15T16:01:05Z No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Dissertação - Adriano Honorato Braga - 2013.pdf: 1269065 bytes, checksum: 31a4446602e6fc177149b700de63b216 (MD5) / Approved for entry into archive by Erika Demachki (erikademachki@gmail.com) on 2014-12-15T16:30:34Z (GMT) No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Dissertação - Adriano Honorato Braga - 2013.pdf: 1269065 bytes, checksum: 31a4446602e6fc177149b700de63b216 (MD5) / Made available in DSpace on 2014-12-15T16:30:34Z (GMT). No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Dissertação - Adriano Honorato Braga - 2013.pdf: 1269065 bytes, checksum: 31a4446602e6fc177149b700de63b216 (MD5) Previous issue date: 2013-10-15 / Scientific studies about bibliographic productions in specific areas of science are becoming common, mainly in the last decade. Such investigations usually make use of bibliometric indices to evaluate relevance of the actors that take part in scientific production process, such as: authors, institutions, venues, and subfields of the scientific area being considered. Many studies have investigated the scientific production in computer science under different views. In this work, its presented an analysis about the production of scientific article in computer science and an analysis of citations among subfields, derived from article citation network. The work present novelty not only because it considers many common sense fields in computer science, but also because it presents citation related measures chronologically. The following bibliometric measures were used: number of publications in each subfield, number of citations received by a subfield, Impact Factor, PageRank, and a measure of diversity of subfields that cite a given subfield. Most of those metrics were proposed to study articles, web pages or scientific journals and they had to be adapted to be applied to the subfield analysis. This work has derived many interesting information to computer science community. It presents an historical evolution of the computer science subfields, showing how interest in publishing in subfields and how citations among subfields have evolved during the years. Some trends are revealed, some patterns are recognized to be stable along the time and some subfields are becoming less attractive than others. / Trabalhos que analisam as produções bibliográficas nos mais variados ramos da ciência têm se tornados comuns, principalmente na última década. Tais análises geralmente utilizam-se de índices ou medidas propostas para avaliar relevância de diferentes atores envolvidos no processo de produção científica, tais como: autores, instituições, veículos de publicação e subáreas do ramo da ciência considerado. Vários trabalhos têm investigado a produção científica em ciência da computação sob diversos aspectos. Neste trabalho é apresentado um estudo sobre a produção de artigos científicos nas subáreas da computação, bem como uma análise das citações entre as subáreas, derivadas das citações existentes nos artigos pertencentes a cada subárea. Esse estudo apresenta novidade não apenas pela abrangência das subáreas da computação analisadas, mas principalmente por levar em consideração o aspecto cronológico (ano de publicação) do comportamento de cada subárea sob diferentes índices bibliométricos: quantidade de publicações, quantidades de citações recebidas, PageRank, Fator de impacto e um índice para aferir se uma determinada subárea é citada diversificadamente por várias áreas ou se as citações são feitas principalmente por determinado grupo de subáreas. Algumas dessas medidas utilizadas tradicionalmente para mensurar relevância de artigos ou veículos de publicação e tiveram que ser adaptadas para a análise de subáreas. O trabalho permitiu derivar informações interessantes para a comunidade científica em ciência da computação. É apresentada a evolução histórica das subáreas da computação, mostrando como o interesse por autores e como as citações entre subáreas têm mudado ao longo do tempo. Algumas tendências são reveladas, alguns padrões são reconhecidos como sendo cronologicamente estáveis e algumas subáreas têm se tornado menos atrativas do que outras.
14

Analysis and optimization of pilot-aided adaptive coded modulation under noisy channel state information and antenna diversity

Duong, Duc Van January 2006 (has links)
<p>The thesis is largely built on a collection of published and submitted papers where the main focus is to analyze and optimize single-carrier adaptive coded modulation systems with and without antenna diversity. Multidimensional trellis codes are used as component codes. The majority of the analysis is done with both estimation and prediction errors being incorporated. Both channel estimation and prediction are performed using a pilot-symbol-assisted modulation scheme. Thus, known pilot symbols (overhead information) must be transmitted; which consumes power and also degrades system spectral efficiency. Both power consumption and pilot insertion frequency are optimized such that they are kept at necessary values to maximize system throughput without sacrificing the error rate performance. The results show that efficient and reliable system performance can be achieved over a wide range of the considered average channel quality. Going from a single-input single-output system to both spatially uncorrelated and correlated single-input multiple-ouput (SIMO) systems, and further to an uncorrelated multiple-input multiple-output (MIMO) diversity system, is the evolution of the thesis. In the SIMO case, maximum ratio combining is used to combine the incoming signals, whereas the signals are space-time combined in the MIMO diversity system. The multiple-input single-output system comes out as a special case of a MIMO system. Besides the spatially uncorrelated antenna array, the effect of spatial correlation is also considered in the SIMO case. In this case, only prediction error is considered and channel estimation is assumed to be perfect. At first, the impact of spatial correlation in a predicted system originally designed to operate on uncorrelated channels is quanitifed. Then, a maximum a posteriori (MAP)-optimal “space-time predictor” is derived to take spatial correlation into account. As expected, the results show that the throughput is still lower than the uncorrelated system, but the degradation is decreased when the MAP-optimal space-time predictor is used. Thus, by exploiting the correlation properly, the degradation can be reduced. By numerical examples, we demonstrate the potential effect of limiting the predictor complexity, of fixing the pilot spacing, as well as of assuming perfect estimation. The two first simplifications imply lower system complexity and feedback rate, whereas the last assumption is usually made to ease the mathematical analysis. The numerical examples indicate that all the simplifications can be done without serious impact on the predicted system performance.</p>
15

Analysis and optimization of pilot-aided adaptive coded modulation under noisy channel state information and antenna diversity

Duong, Duc Van January 2006 (has links)
The thesis is largely built on a collection of published and submitted papers where the main focus is to analyze and optimize single-carrier adaptive coded modulation systems with and without antenna diversity. Multidimensional trellis codes are used as component codes. The majority of the analysis is done with both estimation and prediction errors being incorporated. Both channel estimation and prediction are performed using a pilot-symbol-assisted modulation scheme. Thus, known pilot symbols (overhead information) must be transmitted; which consumes power and also degrades system spectral efficiency. Both power consumption and pilot insertion frequency are optimized such that they are kept at necessary values to maximize system throughput without sacrificing the error rate performance. The results show that efficient and reliable system performance can be achieved over a wide range of the considered average channel quality. Going from a single-input single-output system to both spatially uncorrelated and correlated single-input multiple-ouput (SIMO) systems, and further to an uncorrelated multiple-input multiple-output (MIMO) diversity system, is the evolution of the thesis. In the SIMO case, maximum ratio combining is used to combine the incoming signals, whereas the signals are space-time combined in the MIMO diversity system. The multiple-input single-output system comes out as a special case of a MIMO system. Besides the spatially uncorrelated antenna array, the effect of spatial correlation is also considered in the SIMO case. In this case, only prediction error is considered and channel estimation is assumed to be perfect. At first, the impact of spatial correlation in a predicted system originally designed to operate on uncorrelated channels is quanitifed. Then, a maximum a posteriori (MAP)-optimal “space-time predictor” is derived to take spatial correlation into account. As expected, the results show that the throughput is still lower than the uncorrelated system, but the degradation is decreased when the MAP-optimal space-time predictor is used. Thus, by exploiting the correlation properly, the degradation can be reduced. By numerical examples, we demonstrate the potential effect of limiting the predictor complexity, of fixing the pilot spacing, as well as of assuming perfect estimation. The two first simplifications imply lower system complexity and feedback rate, whereas the last assumption is usually made to ease the mathematical analysis. The numerical examples indicate that all the simplifications can be done without serious impact on the predicted system performance.
16

Estudi de les inèrcies estructurals en anàlisis de correspondències. Aportacions per a una millora de les anàlisis

Daunis i Estadella, Josep 11 February 2005 (has links)
La memòria d'aquesta tesi doctoral s'estructura en un primer capítol on es descriuen els objectius de la tesi i l'organització del treball de recerca. Després, el Capítol 2: Anàlisis factorials de dades es destina a presentar les eines utilitzades en les anàlisis factorials de dades. S'introdueix una anàlisi de tipus general, l'anàlisi canònica per a la comparació de dos grups de variables, i llavors es generalitza per a mes de dos grups. Presentem les anàlisis de correspondències, simples i múltiples, com un cas particular de les anàlisis canòniques, però també des d'una perspectiva més clàssica. Es proporcionen tècniques de representació gràfica - representacions simètriques i Biplots - i el concepte d'inèrcia.En el Capítol 3: Models loglineals i models gràfics es desenvolupen els models loglineals i els models gràfics, el concepte d'independència condicional i el seu ús. Es desenvolupen, a continuació, la formulació dels models loglineals, les restriccions que els caracteritzen -suma zero o còrner zero- i les relacions de transició. Es realitza un estudi de la influència dels paràmetres en la generació de models, sobretot de la importància del termes de les interaccions sobre els termes independents i els efectes principals. En aquest capítol s'introdueix la deviància, com a raó de versemblança entre dos models, la seva expressió i relació amb l'estadístic &#967;2 i altres indicadors de divergència de models.El Capítol 4: Estudi de les inèrcies en anàlisis de correspondències s'inicia amb la relació entre la inèrcia, el coeficient de contingència i la deviància. A continuació, s'estudien les descomposicions de la inèrcia com a contribucions dels individus, modalitats o variables i s'apliquen a l'estudi de matrius quadrades. En referència a les anàlisis de correspondències múltiples de la taula de Burt, es fa la descomposició de les inèrcies per blocs i s'estudia la problemàtica dels blocs diagonals. S'estudien metodologies de tractament i es fa una proposta de metodologia per al tractament de matrius quadrades no simètriques basada en una doble descomposició, per una part en l'anàlisi de la simetria-no simetria i per l'altra utilitzant la reconstitució factorial de la part simètrica, basada en un algorisme k-EM, on k és l'ordre de reconstitució. La reconstitució k-EM pot ser aplicada a les taules diagonals de Burt i ens porta a una anàlisi equivalent al Joint Correspondence Analysis.En el Capítol 5: ACM respecte un model i ACM condicional es dedica a presentar les ACM sobre un model i l'ACM condicional, on una variable qualitativa externa juga el paper de partició. L'aportació es basa en realitzar l'estudi de la inèrcia i la seva descomposició, en dues parts lligades a la variable condicionadora externa: la inèrcia inter i la inèrcia intra. Es troba la formulació de la distribució i mitjançant aquesta, s'interpreta la importància o no del condicionament. Així doncs, usant l'ACM condicional i els models loglineals estudiem el comportament de la inèrcia en relació al model. El Capítol 6: ACM multicondicional considera les problemàtiques que genera la implementació de l'ACM multicondicional, ja que no es pot generalitzar trivialment del cas simple. Mitjançant l'estudi de les inèrcies condicionals i els models loglineals es desenvolupa una proposta d'anàlisi multicondicional. Aquests resultats són comparats amb els que s'obtenen en un procés de modelització loglineal. S'aplica la proposta a un exemple en el Capítol 7.El treball de recerca finalitza amb unes conclusions on es resumeixen les principals aportacions i s'indiquen quines podrien ser algunes línies de recerca futures en aquest camp i s'annexen les macros programades. / The research work memory is structured in a first chapter with the description of the objectives of the doctoral thesis and the research work organization. Then, the Chapter 2 Descriptive factorial analysis is exclusively dedicated to present the tools used in factorial analysis. A general analysis, the canonical analysis, to compare two groups of variables is introduced, and then it is generalized to more than two questions. We present correspondence analysis, simple and multiple, as a particular case of canonical analysis, but we present both methods also from a more classical point of view. We also introduce graphical techniques -symmetric displays and Biplots- and the inertia concept.Chapter 3 Loglinear and graphical models introduces briefly loglinear models and graphical models, the conditional independence concept and its use. Next, we develop the loglinear model formula and the constraints that characterize the model -zero sum or zero corner treatment- and the transition relations. We make a study of the influence of the parameters over the model generation, especially about the significance of interaction terms over principal and independent terms. In this chapter we introduce the deviance, as a likelihood ratio between two models, its expression and its relation with the &#967;2 statistic and other model divergence indicators. In Chapter 4 Study of the inertias in correspondence analysis we start with the relation among inertias, the contingence coefficient and deviance. Next, we study the inertia decomposition as the contribution of each individual, category or variable. It's applied to study the case of square matrices. With reference to the multiple correspondence analysis of the Burt table, we decompose inertia by blocks and we investigate the influence of the blocks of the diagonal. A summary of several treatment methodologies is done. We propose a new methodology to treat squared skew-symmetric matrices, based on a double decomposition, on the one hand, in the symmetry-skew-symmetry analysis and on the other using the factorial reconstitution of the symmetric part, based on a k-EM algorithm, where k is the reconstitution order. The k-EM reconstitution methodology can be applied to the diagonal tables of a Burt table, which leads a result equivalent to Joint Correspondence Analysis.In Chapter 5 - MCA with respect to a model and conditional MCA- firstly we start presenting MCA with respect to a model. Secondly we discuss conditional MCA, where an external variable plays a partitioning role. The contribution is based on studying the inertia and its decomposition in two parts linked to the external conditioning variables, the inter and intra inertia. Next, we find their distribution function and, by means of this, we can test the significance of the conditioning variable. Therefore, using the conditional MCA and loglinear models introduced before, we study the inertia behaviour with relation to the model and with different relation levels between the variables.The Chapter 6 -Multiconditional MCA- consideres problems generated by the implementation of multiple conditional analysis, since it is not possible to generalize this definition to the simple conditional case. By means of the study of conditional inertias and loglinear models, we develop our proposal for a multiconditional analysis. These results are compared with the results obtained in a loglinear modelling process. We apply our proposal to a data example in Chapter 7. The dissertation ends with a chapter of conclusions which sums up our principal contributions and suggests some future research lines in this field of investigation and with the macros programmed and used.
17

Research and Development of DSP Based System for Tracking An Arbitrary-Shaped Object

Lin, Wei-Ting 12 July 2005 (has links)
A DSP-based system is developed in this thesis for tracking ¡§an arbitrary-shaped object¡¨. It uses CCD camera to capture images, and detects in the video sequence. When we want to track a target that we interest, we can make the target in the view of camera. If the target move, the system will lock it and extract its contour by using active contour model. After extracting contour, the system will start to track target and shows the locked image on the LCD screen. The tracking system includes three sub-systems : ¡§Moving Object Detection¡¨, ¡§Active Contour Model¡¨, and ¡§Contour Matching¡¨. From the results of experiment, it can meet the expectation and gain good performance and robustness.
18

Inverse Transformed Density Rejection for Unbounded Monotone Densities

Hörmann, Wolfgang, Leydold, Josef, Derflinger, Gerhard January 2007 (has links) (PDF)
A new algorithm for sampling from largely abitrary monotone, unbounded densities is presented. The user has to provide a program to evaluate the density and its derivative and the location of the pole. Then the setup of the new algorithm constructs different hat functions for the pole region and for the tail region, respectively. For the pole region a new method is developed that uses a transformed density rejection hat function of the inverse density. As the order of the pole is calculated in the setup, conditions that guarantee the correctness of the constructed hat functions are provided. Numerical experiments indicate that the new algorithm works correctly and moderately fast for many different unbounded densities. (c) ACM, (2007). This is the author's version of the work. It is posted here by permission of ACM for your personal use. Not for redistribution. (author's abstract) / Series: Research Report Series / Department of Statistics and Mathematics
19

Caracterização dos sistemas de produção leiteiros na região oeste do Paraná por meio de análise multivariada / Characterization of dairy production systems in the western region by Paraná multivariate analysis

Defante, Leslié 29 July 2011 (has links)
Made available in DSpace on 2017-07-10T17:48:26Z (GMT). No. of bitstreams: 1 Leslie_Defante.pdf: 812707 bytes, checksum: d92d4165f390781200d13f9907af6b34 (MD5) Previous issue date: 2011-07-29 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / In order to characterize the farms, by identifying characteristics of production, milk composition and influence of the management systems of hygiene and sanitary production of milk - SPL of the western region of Paraná State. A study was conducted in 23 SPL, with the collection of data from a semi-structured questionnaire guide and collection of samples of raw milk and cooled water reservoirs.. analyses were performed using physical-chemical (fat, protein, lactose, total solids) of somatic cell counting (SCC) and total bacterial counting (TBC). For microbiological tests were performed to determine the most probable number of total coliform and thermotolerant coliform by multiple tube method. We evaluated the differences found in production systems by means of multivariate statistical techniques, namely: multiple correspondence analysis (MCA), principal component analysis (PCA) and cluster analysis, the milk production and herd feeding management, milking management, reproductive management, disease control, and finally the marketing of milk. The variables that best explained the diversity of the systems were: the amount of milk produced, lactating cows, repetition of estrus, based on feed and milking practices, hygiene and mastitis test ceilings. While the high counts of CBT, CCS and the presence of total coliforms and thermotolerant in some dairy production systems have proved to be indicative of deficiencies in hygiene procedures for milking, cleaning and sanitizing of milking equipment, associated with inadequate cooling of milk. Delivering the decreased concentrations of the components fat, protein and total solids, causing changes in the quality of milk and dairy products. The typology of production systems allowed to portray the diversity in the organization and manner of production, enabling the simplification of the universe of producers, allowing us to tailor production strategies, managing and improving the quality of milk for each system / Objetivou-se avaliar as características de 23 sistemas de produção de leite (SPL) na região Oeste do Estado do Paraná. O levantamento das características de produção, composição e qualidade do leite e do manejo higiênico-sanitário foi obtido pela coleta de dados a partir de um questionário guia semi-estruturado e pela coleta de amostras de leite de tanque e água de reservatórios. As amostras de leite foram analisadas quanto às características físico-químicas (gordura, proteína, lactose, sólidos totais), contagem de células somáticas, contagem bacteriana total e microbiológicas no leite. Para as análises microbiológicas foram realizadas a determinação do número mais provável de coliformes totais e coliformes termotolerantes pelo método de tubos múltiplos. Posteriormente, as diversidades encontradas nos SPL foram analisadas por meio de técnicas estatísticas multivariadas: análise de correspondências múltiplas (ACM), análise de componentes principais (ACP) e análise de cluster; quanto a produtividade do rebanho, manejo alimentar, manejo de ordenha, manejo reprodutivo, controle sanitário, e por último a comercialização do leite. As variáveis que melhor explicaram as diversidades dos SPL foram: a quantidade de leite produzido, o número de vacas lactantes, repetição de cio, base forrageira e as práticas de ordenha (teste de mastite e higienização dos tetos). Enquanto que elevados valores de CBT, CCS e presença de coliformes totais e termotolerantes em alguns SPL demonstraram ser um indicativo de deficiência nos procedimentos de higiene na ordenha, na limpeza e sanitização dos equipamentos de ordenha. Isso proporcionou uma a diminuição das concentrações dos componentes gordura, proteína e sólidos totais, ocasionando alterações na qualidade do leite. A tipologia dos sistemas de produção permitiu retratar a diversidade existente na organização e na forma de produção, possibilitando a simplificação do universo dos produtores, e a adequação de estratégias de produção, gestão e melhoria da qualidade do leite para cada sistema
20

Experimental Study and Modeling of the GM-I Dependence of Long-Channel Mosfets

Cheng, Michael Fong 01 March 2019 (has links)
This thesis describes an experimental study and modeling of the current-transconductance dependence of the ALD1106, ALD1107, and CD4007 arrays. The study tests the hypothesis that the I-gm dependence of these 7.8 µm to 10 µm MOSFETs conforms to the Advanced Compact Model (ACM). Results from performed measurements, however, do not support this expectation. Despite the relatively large length, both ALD1106 and ALD1107 show sufficiently pronounced ‘short-channel’ effects to render the ACM inadequate. As a byproduct of this effort, we confirmed the modified ACM equation. With an m factor of approximately 0.6, it captures the I-gm dependence with sub-28% maximum error and sub-10% average error. The paper also introduces several formulas and procedures for I-gm model extraction and tuning. These are not specific to the ALD transistor family and can apply to MOSFETs with different physical size and electrical performance.

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