Dissertations / Theses on the topic 'Modern Synthesi'
To see the other types of publications on this topic, follow the link: Modern Synthesi.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Modern Synthesi.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Andriushchenko, Roman. "Computer-Aided Synthesis of Probabilistic Models." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2020. http://www.nusl.cz/ntk/nusl-417269.
Full textAbstract:
Předkládaná práce se zabývá problémem automatizované syntézy pravděpodobnostních systémů: máme-li rodinu Markovských řetězců, jak lze efektivně identifikovat ten který odpovídá zadané specifikaci? Takové rodiny často vznikají v nejrůznějších oblastech inženýrství při modelování systémů s neurčitostí a rozhodování i těch nejjednodušších syntézních otázek představuje NP-těžký problém. V dané práci my zkoumáme existující techniky založené na protipříklady řízené induktivní syntéze (counterexample-guided inductive synthesis, CEGIS) a na zjemňování abstrakce (counterexample-guided abstraction refinement, CEGAR) a navrhujeme novou integrovanou metodu pro pravděpodobnostní syntézu. Experimenty nad relevantními modely demonstrují, že navržená technika je nejenom srovnatelná s moderními metodami, ale ve většině případů dokáže výrazně překonat, někdy i o několik řádů, existující přístupy.
2
Aribi, Fallia. "Development and biological evaluation of novel fluorinated ingredients for modern crop protection." Thesis, Strasbourg, 2017. http://www.theses.fr/2017STRAF020.
Full textAbstract:
Ce doctorat a permis la conception de nouvelles molécules destinées aux développements de futurs produits phytosanitaires. Tout d’abord, la synthèse d’alpha,alpha-difluoro-beta-hydroxy cétones a été réalisée. Motif déjà reconnu dans le domaine pharmaceutique, nous voulions étendre son champ d’application à l’agrochimie. Une série de composés possédant une activité biologique en tant qu’agonistes des récepteurs GABA a été synthétisée. Ils ont été obtenus à l’issu d’une synthèse convergente nécessitant une réaction de couplage entre un aldéhyde aromatique et un intermédiaire alpha,alpha-difluoro-beta-trifluoromethyldihydroxy cétone. L’analyse biologique de nos produits a fait ressortir un type de famille spécifique. Une approche prodrug a débuté afin d’en affiner la structure et d’en faire ressortir un hit. Dans un second temps, le développement d’une série de quinoléines substituées par des groupements fluorés en position 2 et 4 a été conduit. Ces molécules peu décrites dans la littérature fûrent synthétisées dans des conditions douces avec de bons rendements et une complète régiosélectivité, inspirée par les réactions de Combes et de Meth-Cohn utilisant un Réactif Fluoroalkyl Amine (FARs). La post-fonctionnalisation en position 3 et 8 a permis l’exemplification de ces composés. Une étude physico-chimique réalisée sur une série homogène a apporté des informations complémentaires sur leurs propriétés électroniques. Bien qu’aucune molécule n’ait montré d’activité biologique, nous avons pu lors de ce projet réaliser la synthèse de nouvelles quinoléines et évaluer des FARs dans la synthèse de molécules inconnues de la littérature jusqu’à ce jourThis PhD thesis allowed the conception of new molecules for the development of novel phytosanitary ingredients. First, the synthesis of alpha,alpha-difluoro-betahydroxy ketones was performed. Since this motif is already known in the pharmaceutical field, we decided to extend their application to the agrochemical field. A series of compounds with biological activities as GABA agonist receptors was synthesized. They were obtained by a convergent method after a coupling reaction between benzaldehydes and alpha,alpha-difluoro-beta-trifluoromethyldihydroxy ketone intermediates. Biological analysis highlighted a specific family of compounds. A prodrug approach was applied to tune the structure and allowed the discovery of a hit. Second, the development of a series of 2,4-(fluoroalkyl)-substituted quinoline derivatives was conducted. Scarcely described in literature, these molecules were obtained under smooth conditions, with good yields and a complete regioselectivity, inspired by Combes and Meth- Cohn reactions using Fluoroalkyl Amino Reagents (FARs). Post-functionalization in position 3 and 8 allowed us to increase the scope of the reaction. A physico-chemical study gave complementary informations on their electronical properties. Although none of these molecules have shown biological activity, we have during this project realized the synthesis of new quinolines and evaluated the use of FARs in the synthesis of unknown fluorinated molecules
3
Gonçalves, Josilena Maria Zanello. "Integração das artes no Paraná - 1950 - 1970: a conquista do espaço público." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/16/16131/tde-10102006-143702/.
Full textAbstract:
A partir da segunda metade da década de 1940,a arte moderna deixa o confinamento das galerias e ganha as ruas através de sua integração com a arquitetura. Esta pesquisa estuda a relação entre arquitetura moderna e arte no Paraná , no período compreendido entre os anos 1950 e 1970, e sua ação conjunta no sentido de consolidar o projeto moderno no Estado, através do estudo de murais concebidos integrados a obras de arquitetura.From the second half of the decade of 1940, the modern art leaves the confinement of the galleries and gains the streets through its integration with the architecture.This research studies the relation between architecture and modern art in the Paraná, in the period between years 1950 and 1970,and its joint action in the direction to consolidate the modern project in the State, through the study of murals conceived integrated with architecture.
4
Halabi, Nawar. "Modern standard Arabic phonetics for speech synthesis." Thesis, University of Southampton, 2016. https://eprints.soton.ac.uk/409695/.
Full textAbstract:
Arabic phonetics and phonology have not been adequately studied for the purposes of speech synthesis and speech synthesis corpus design. The only sources of knowledge available are either archaic or targeted towards other disciplines such as education. This research conducted a three-stage study. First, Arabic phonology research was reviewed in general, and the results of this review were triangulated with expert opinions – gathered throughout the project – to create a novel formalisation of Arabic phonology for speech synthesis. Secondly, this formalisation was used to create a speech corpus in Modern Standard Arabic and this corpus was used to produce a speech synthesiser. This corpus was the first to be constructed and published for this dialect of Arabic using scientifically-supported phonological formalisms. The corpus was semi-automatically annotated with phoneme boundaries and stress marks; it is word-aligned with the orthographical transcript. The accuracy of these alignments was compared with previous published work, which showed that even slightly less accurate alignments are sufficient for producing high quality synthesis. Finally, objective and subjective evaluations were conducted to assess the quality of this corpus. The objective evaluation showed that the corpus based on the proposed phonological formalism had sufficient phonetic coverage compared with previous work. The subjective evaluation showed that this corpus can be used to produce high quality parametric and unit selection speech synthesisers. In addition, it showed that the use of orthographically extracted stress marks can improve the quality of the generated speech for general purpose synthesis. These stress marks are the first to be tested for Modern Standard Arabic, which thus opens this subject for future research.
5
Rezende, Suzanna Ramalho de. "Paulo Werneck: a produção mural e a arquitetura moderna brasileira." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/93/93131/tde-04072018-104956/.
Full textAbstract:
Esta dissertação tem como intenção analisar a obra parietal de Paulo Werneck, ilustrador, gravador, muralista e mosaicista, cuja produção é fundamental para compreender a arte mural de meados do século XX no Brasil. Para tanto, este estudo se inicia a partir de uma breve explanação sobre o desenvolver da arquitetura moderna brasileira e a sua consolidação como uma linguagem própria, independente da matriz europeia. A seguir, será apresentado o conceito estético síntese das artes, que é geralmente utilizado pela historiografia tradicional para justificar o alastre da arte mural em edificações racionalistas a partir da década de 40. Nessa parte do trabalho, a intenção é apresentar o desenvolvimento histórico do tema, do seu surgimento até a leitura que irá impactar a obra de arquitetos como Le Corbusier - pela qual a questão chega no país- Lúcio Costa e Oscar Niemeyer. Por fim, a primeira parte do trabalho se debruça sobre a arte mural brasileira- seja ela pintura, azulejaria ou mosaico- tentando compreender a sua motivação estética e política. A segunda parte do trabalho é dedicada à figura e a obra musiva de Paulo Werneck. Nela apresenta-se o seu desenvolvimento como artista, o seu relacionamento com a arquitetura moderna, a sua passagem da ilustração para a arte mural e a sua chegada ao mosaico, técnica na qual se tornará um experto. Também é analisada as visualidades presentes no seu trabalho, da figuração ao abstracionismo, a partir de estudos de caso das obras mais significativas do artista, buscando sempre relacionar as suas escolhas com o que estava sendo produzindo no país na mesma época. Portanto, esse trabalho se dedica a estudar a arte mural brasileira e a importância dos painéis de Werneck, artista responsável pela renovação da linguagem do mosaico no Brasil e, quiçá, no mundo.This dissertation analyzes the parietal work of Paulo Werneck, illustrator, engraver, muralist and mosaic designer whose production is fundamental to understand the mid-twentieth century mural art in Brazil. In this regard, the study begins with a brief explanation about the development of Brazilian modern architecture and its consolidation as a language of its own, independent of the European matrix. Then, the aesthetic concept of \"synthesis of the arts\" is going to be presented. Usually, the concept is used by traditional historiography to justify the spreading of mural art in rationalist constructions from the 1940s. This part of the dissertation intends to point out the historical development of the theme, from its appearance until the \"reading\" that would make an impact in the work of architects such as Le Corbusier the aesthetic concept arrives in Brazil via his work - Lucio Costa and Oscar Niemeyer. Finally, the first part of the dissertation focuses on the Brazilian art mural such as painting, tilery or mosaic making and tries to comprehend its aesthetic and political motivation. The second part of the dissertation is dedicated to the figure and the musive work of Paulo Werneck. It presents his development as an artist, his relationship with the modern architecture, his transition from illustration to the mural art as well as his approach to the mosaic art whose technique would convert him into an expert. Also, it analyzes the visualities in his work from the figuration to the abstractionism through case studies of the most significant works of the artist, always trying to connect his choices with things that were being produced in the country at that time. In conclusion, this dissertation intends to study the Brazilian mural art and the importance of the panels of Paulo Werneck, the artist who is responsible for the renewal of the mosaic language in Brazil and, perhaps, in the world.
6
Lam, Son Ngoc. "Glycosyl iodides : a modern tool for oligosaccharide synthesis /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2003. http://uclibs.org/PID/11984.
Full text
7
Hahn, Henrik. "Expressive sampling synthesis. Learning extended source-filter models from instrument sound databases for expressive sample manipulations." Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066564/document.
Full textAbstract:
Dans cette thèse un système de synthèse sonore imitative sera présenté, applicable à la plupart des instruments de quasi-harmoniques. Le système se base sur les enregistrements d’une note unique qui représentent une version quantifiée de l'espace de timbre possible d'un instrument par rapport à sa hauteur et son intensité. Une méthode de transformation permet alors de générer des signaux sonores de valeurs continues des paramètres de contrôle d'expression qui sont perceptuellement cohérent avec ses équivalents acoustiques. Un modèle paramétrique de l'instrument se présente donc basé sur un modèle de filtre de source étendu avec des manipulations distinctes sur les harmoniques d’un signal et ses composantes résiduelles. Une procédure d'évaluation subjective sera présentée afin d’évaluer une variété de résultats de transformation par une comparaison directe avec des enregistrements non modifiés, afin de comparer la perception entre les résultats synthétiques et leurs équivalents acoustiquesWithin this thesis an imitative sound synthesis system will be introduced that is applicable to most quasi-harmonic instruments. The system bases upon single-note recordings that represent a quantized version of an instrument's possible timbre space with respect to its pitch and intensity dimension. A transformation method then allows to render sound signals with continuous values of the expressive control parameters which are perceptually coherent with its acoustic equivalents. A parametric instrument model is therefore presented based on an extended source-filter model with separate manipulations of a signal’s harmonic and residual components. A subjective evaluation procedure will be shown to assess a variety of transformation results by a direct comparison with unmodified recordings to determine how perceptually close the synthesis results are regarding their respective acoustic correlates
8
BERARDI, Daniela. "Automatic Service Composition. Models, Techniques and Tools." Doctoral thesis, La Sapienza, 2005. http://hdl.handle.net/11573/917069.
Full text
9
Fokt, Simon. "Defining art culturally : modern theories of art : a synthesis." Thesis, University of St Andrews, 2013. http://hdl.handle.net/10023/3675.
Full textAbstract:
Numerous theories have attempted to overcome the anti-essentialist scepticism about the possibility of defining art. While significant advances have been made in this field, it seems that most modern definitions fail to successfully address the issue of the ever-changing nature of art raised by Morris Weitz, and rarely even attempt to provide an account which would be valid in more than just the modern Western context. This thesis looks at the most successful definitions currently defended, determines their strengths and weaknesses, and offers a new, cultural definition which can preserve the good elements of other theories, solve or avoid their problems, and have a scope wide enough to account for art of different times and cultures. The resulting theory is a synthetic one in that it preserves the essential institutionalism of Dickie's institutional views, is inspired by the historical and functional determination of artistic phenomena present in Levinson's historicism and Beardsley's functionalism, and presents the reasons for something becoming art in a disjunctive form of Gaut's cluster account. Its strengths lie in the ability to account for the changing art-status of objects in various cultures and at various times, providing an explanation of not only what is or was art, but also how and why the concept 'art' changes historically and differs between cultures, and successfully balancing between the over-generalisations of ahistorical and universalist views, and the uninformativeness of relativism. More broadly, the cultural theory stresses the importance of treating art as a historical phenomenon embedded in particular social and cultural settings, and encourages cooperation with other disciplines such as anthropology and history of art.
10
Lue, Bena-Marie. "Biosynthesis of phenolic lipid models using oleyl alcohol and triolein." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=80324.
Full textAbstract:
The overall objective of this study was the optimization of a model enzymatic system in organic solvent media for the biosynthesis of selected phenolic lipid compounds. The model enzymatic system consisted of cinnamic acid and oleyl alcohol as substrates using commercial immobilized lipase (Novozym 435) from Candida antarctica. The experimental findings showed that an increase in the hydrophobicity of the solvent mixture and a decrease in the aw values of the reaction medium increased the initial enzymatic activity and bioconversion yield; the use of an iso-octane and butanone solvent mixture (85:15, v/v) and an initial aw of 0.05 resulted in an initial enzymatic activity of 192.7 nmol product/g enzyme/min and a corresponding bioconversion yield of 95.3% after a 16-day reaction period.
11
Wang, Qi. "Statistical Models for Human Motion Synthesis." Thesis, Ecole centrale de Marseille, 2018. http://www.theses.fr/2018ECDM0005/document.
Full textAbstract:
Cette thèse porte sur la synthèse de séquences de motion capture avec des modèles statistiques. La synthèse de ce type de séquences est une tâche pertinente pour des domaines d'application divers tels que le divertissement, l'interaction homme-machine, la robotique, etc. Du point de vue de l'apprentissage machine, la conception de modèles de synthèse consiste à apprendre des modèles génératifs, ici pour des données séquentielles. Notre point de départ réside dans deux problèmes principaux rencontrés lors de la synthèse de données de motion capture, assurer le réalisme des positions et des mouvements, et la gestion de la grande variabilité dans ces données. La variabilité vient d'abord des caractéristiques individuelles, nous ne bougeons pas tous de la même manière mais d'une façon qui dépend de notre personnalité, de notre sexe, de notre âge de notre morphologie, et de facteurs de variation plus court terme tels que notre état émotionnel, que nous soyons fatigués, etc.Une première partie présente des travaux préliminaires que nous avons réalisés en étendant des approches de l'état de l'art basées sur des modèles de Markov cachés et des processus gaussiens pour aborder les deux problèmes principaux liés au réalisme et à la variabilité. Nous décrivons d'abord une variante de modèles de Markov cachés contextuels pour gérer la variabilité dans les données en conditionnant les paramètres des modèles à une information contextuelle supplémentaire telle que l'émotion avec laquelle un mouvement a été effectué. Nous proposons ensuite une variante d'une méthode de l'état de l'art utilisée pour réaliser une tâche de synthèse de mouvement spécifique appelée Inverse Kinematics, où nous exploitons les processus gaussiens pour encourager le réalisme de chacune des postures d'un mouvement généré. Nos résultats montrent un certain potentiel de ces modèles statistiques pour la conception de systèmes de synthèse de mouvement humain. Pourtant, aucune de ces technologies n'offre la flexibilité apportée par les réseaux de neurones et la récente révolution de l'apprentissage profond et de l'apprentissage Adversarial que nous abordons dans la deuxième partie.La deuxième partie de la thèse décrit les travaux que nous avons réalisés avec des réseaux de neurones et des architectures profondes. Nos travaux s'appuient sur la capacité des réseaux neuronaux récurrents à traiter des séquences complexes et sur l'apprentissage Adversarial qui a été introduit très récemment dans la communauté du Deep Learning pour la conception de modèles génératifs performants pour des données complexes, notamment images. Nous proposons une première architecture simple qui combine l'apprentissage Adversarial et des autoencodeurs de séquences, qui permet de mettre au point des systèmes performants de génération aléatoire de séquences réalistes de motion capture. A partir de cette architecture de base, nous proposons plusieurs variantes d'architectures neurales conditionnelles qui permettent de concevoir des systèmes de synthèse que l'on peut contrôler dans une certaine mesure en fournissant une information de haut niveau à laquelle la séquence générée doit correspondre, par exemple l'émotion avec laquelle une activité est réalisée. Pour terminer nous décrivons une dernière variante qui permet de réaliser de l'édition de séquences de motion capture, où le système construit permet de générer une séquence dans le style d'une autre séquence, réelleThis thesis focuses on the synthesis of motion capture data with statistical models. Motion synthesis is a task of interest for important application fields such as entertainment, human-computer interaction, robotics, etc. It may be used to drive a virtual character that can be involved in the applications of the virtual reality, animation films or computer games. This thesis focuses on the use of statistical models for motion synthesis with a strong focus on neural networks. From the machine learning point of view designing synthesis models consists in learning generative models. Our starting point lies in two main problems one encounters when dealing with motion capture data synthesis, ensuring realism of postures and motion, and handling the large variability in the synthesized motion. The variability in the data comes first from core individual features, we do not all move the same way but accordingly to our personality, our gender, age, and morphology etc. Moreover there are other short term factors of variation like our emotion, the fact that we are interacting with somebody else, that we are tired etc. Data driven models have been studied for generating human motion for many years. Models are learned from labelled datasets where motion capture data are recorded while actors are performed various activities like walking, dancing, running, etc. Traditional statistical models such as Hidden Markov Models, Gaussian Processes have been investigated for motion synthesis, demonstrating strengths but also weaknesses. Our work focuses in this line of research and concerns the design of generative models for sequences able to take into account some contextual information, which will represent the factors of variation. A first part of the thesis present preliminary works that we realised by extending previous approaches relying on Hidden Markov Models and Gaussian Processes to tackle the two main problems related to realism and variability. We first describe an attempt to extend contextual Hidden Markov Models for handling variability in the data by conditioning the parameters of the models to an additional contextual information such as the emotion which which a motion was performed. We then propose a variant of a traditional method for performing a specific motion synthesis task called Inverse Kinematics, where we exploit Gaussian Processes to enforce realism of each of the postures of a generated motion. These preliminary results show some potential of statistical models for designing human motion synthesis systems. Yet none of these technologies offers the flexibility brought by neural networks and the recent deep learning revolution.The second part of the thesis describes the works we realized with neural networks and deep architectures. It builds on recurrent neural networks for dealing with sequences and on adversarial learning which was introduced very recently in the deep learning community for designing accurate generative models for complex data. We propose a simple system as a basis synthesis architecture, which combines adversarial learning with sequence autoencoders, and that allows randomly generating realistic motion capture sequences. Starting from this architecture we design few conditional neural models that allow to design synthesis systems that one can control up to some extent by either providing a high level information that the generated sequence should match (e.g. the emotion) or by providing a sequence in the style of which a sequence should be generated
12
Shi, Bo. "A speech synthesis-by-rule system for modern standard Chinese." Thesis, University College London (University of London), 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.296520.
Full text
13
Masarapu, Charan. "Carbon nanotubes synthesis, properties and applications in modern electronic devices /." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 226 p, 2008. http://proquest.umi.com/pqdweb?did=1654493801&sid=8&Fmt=2&clientId=8331&RQT=309&VName=PQD.
Full textAbstract:
Thesis (Ph.D.)--University of Delaware, 2008.Principal faculty advisors: Dennis W. Prather, Dept. of Electrical & Computer Engineering; and Bingqing Wei, Dept. of Mechanical Engineering. Includes bibliographical references.
14
Brabbs, Noel Stephen. "Synthesis of potential enzyme models." Thesis, University of Cambridge, 1991. https://www.repository.cam.ac.uk/handle/1810/271924.
Full text
15
Sirpatil, Brijesh. "Software Synthesis of SystemC Models." Thesis, Virginia Tech, 2002. http://hdl.handle.net/10919/34255.
Full textAbstract:
Technological advances are providing us with the capability to integrate more and more functionality into a single chip. This is leading to a new design paradigm, System On a Chip (SOC). In SOC designs all the functionality of a system is put inside a single chip, leading to increased performance, reduced power consumption, lower costs, and reduced size. SOC design brings with it new challenges and difficulties, however. The designs are now large, complicated and involve both software and hardware components. The designs have to be modeled at a high level of abstraction before partitioning into hardware and software components for final implementation.
SystemC is a system level modeling language useful for System On a Chip design. It provides various features to perform system level modeling and simulation, which are missing in the generic HDL's such as VHDL and Verilog. The hardware portion of the SystemC models can be synthesized into hardware using commercial tools . The software portion can be rewritten as embedded software for the target processor.
The aim of this thesis is to explore the SOC design process and to define methods for software synthesis of SystemC models. Software synthesis involves translation of SystemC models into code that is suitable for execution on an embedded processor. A simple scheduler that replaces the SystemC simulation kernel is proposed. This scheduler allows SystemC models to be executed directly as embedded software without the need for extensive modification or translation. Application of this process to the development of a GSM speech processing system, including the translation of part of the SystemC model into software that will execute on an embedded processor, is shown and the results are presented.Master of Science
16
Karlsson, Fredrik. "Religion in the making; or, The Modern Prometheus : Om Syntheiströrelsen och samtida religion och religiositet." Thesis, Stockholms universitet, Religionshistoria, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-117213.
Full textAbstract:
Syntheiströrelsen (The Syntheist Movement) kan förstås som en konsekvens av individualismens framfart, kommersialism, globalisering och framväxten av IT-samhället. Syntheiströrelsen strävar efter att återupprätta en kollektiv gemenskap de upplever gått förlorad genom att själva skapa ny religion relevant för samtiden och framtiden. Benämningen deriveras från grekiska – syntheos, den skapade guden. Med avstamp i Den mediterande dalahästen: Religion på nya arenor i samtidens Sverige (Frisk & Åkerbäck 2013) för uppsatsen ett resonemang kring hur Syntheiströrelsen kan förstås utifrån teorier om samtida religion och religiositet. Syntheiströrelsen förklaras mot bakgrund av en mindre intervjustudie med tongivande medlemmar i stockholmsförsamlingen samt undersökning av näraliggande material.
17
Santos, Cíntia Graziela. "Da teoria sintética da evolução à síntese estendida: o papel da plasticidade fenotípica." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/59/59139/tde-05112015-100804/.
Full textAbstract:
O objetivo desta pesquisa histórica é inicialmente descrever um importante evento (A Síntese moderna) que ocorreu na biologia no período entre guerras. Os biólogos evolutivos chegaram a um acordo sob vários aspectos tais como: o gradualismo do processo evolutivo, o conceito de população e fatores ecológicos, dentre outros. Em segundo lugar, introduzir a chamada Síntese expandida analisando um de seus pressupostos a plasticidade fenotípica e seus antecedentes históricos. Procurará elucidar se algumas ideias relacionadas à plasticidade fenotípica já estavam presentes no início do século XX como alegam alguns autores. Além disso, se essas ideias estavam presentes em trabalhos publicados durante o período da Síntese. Esta tese compreende uma Introdução e seis capítulos. A Introdução apresenta o escopo, metodologia e objetivos da pesquisa. O Capítulo 1 apresenta a Síntese evolutiva e suas relações com a Síntese expandida, introduzindo a plasticidade fenotípica. O Capítulo 2 discute os antecedentes históricos da plasticidade fenotípica. O Capítulo 3 descreve alguns experimentos relacionados à plasticidade fenotípica realizados no início do século XX, focalizando as contribuições de Richard Woltereck. O Capítulo 4 analisa as pesquisas relacionadas ao assunto, desenvolvidas nas décadas de 1940 e 1950 por Ivan I. Schmalhausen e Conrad Waddington. O Capítulo 5 lida principalmente com as pesquisas voltadas à plasticidade fenotípica desenvolvidas na década de 1960 por Anthony D. Bradshaw. O Capítulo 6 esboça um panorama das pesquisas relacionadas ao assunto desenvolvidas após a década de 1960. O Capítulo 7 apresenta algumas considerações sobre o que foi discutido nesta tese. Esta pesquisa leva à conclusão de que algumas ideias que podem ser relacionadas à concepção de plasticidade fenotípica já estavam presentes no final do século XIX. A partir daí, houve mudanças em relação à sua abrangência e terminologia. Concepções relacionadas à plasticidade fenotípica também podem ser encontradas durante o período da Síntese em alguns autores como Schmalhausen, por exemplo. Talvez devido a razões de ordem política elas não foram propagadas. Além disso, é possível que não tenham sido compreendidas completamente pela comunidade científica da época.The aim of this historical research is firstly to describe an important event (The Modern synthesis) that took place in biology in the inter-war-years. The evolutionary biologists reached agreement to several respects such as the gradualism of the evolutionary process, the concept of population and ecological factors, among others. Secondly, to introduce the so-called extended synthesis analyzing one of its features - the phenotypic plasticity - and its historical antecedents. It will try to elucidate whether some ideas that could be related to phenotypic plasticity were already present in the beginning of the 20th century as it was claimed by some authors. Besides that, whether such ideas were not present in the works published during the Synthesis period. This thesis comprises an Introduction and six chapters. The Introduction presents the scope of the research, the research method and the aim of the research. Chapter 1 presents the Evolutionary synthesis and its relationship with the Extended synthesis, introducing the phenotypic plasticity. Chapter 2 discusses the historical antecedents of the phenotypic plasticity. Chapter 3 describes some experiments related to phenotypic plasticity performed in the beginning of the 20th century, focusing Richard Woltereck contributions. Chapter 4 analyzes the researches related to the subject performed in the 1940s and 1950s by Ivan I. Schmalhausen and Conrad Waddington. Chapter 5 mainly focuses the inquiries related to phenotypic plasticity made by Anthony D. Bradshaw during the 1960s. Chapter 6 presents an outlook of the researches concerning the subject performed after 1960s. Chapter 7 presents the final remarks concerning the subject of this thesis. This research leads to the conclusion that some ideas that could be related to the conception of phenotypic plasticity were already present in the end of 19th century. From this time onwards there were been made changes mainly related to its scope and terminology. Conceptions related to phenotypic plasticity can also be found during the Synthesis period in some authors such as Schmalhausen. In this case, perhaps due to political reasons they were not propagated. Besides that, it is possibly that they were not completely understood by the scientific community of that time.
18
Rice, M. J. "Synthetic models of cytochrome P450 and photosynthesis." Thesis, University of Cambridge, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233252.
Full textAbstract:
The work presented in this dissertation describes the prepartion and characterisation of various strapped porphyrin compounds which are designed to model cytochrome P450 and the charge separation in photosynthesis. The major part of this work is concerned with models of cytochrome P450. After a brief introduction to the philosophy of modelling, there follows a review of work on the enzyme and various compounds which are designed to reproduce the enzymic characteristics. The synthesis of two singly bridged porphyrins is reported. These incorporate a pendent methyl ester in the centre of the strap and aim to mimic the proposed acylation step in the catalytic cycle. Evaluation as models was performed by a series of experiments involving the addition of potassium superoxide to the manganese complexes of these compounds. Characterisation of the mode of reactivity required the use of many physical techniques and necessitated the synthesis of a radio-labelled sample of one of the porphyrins. The results obtained suggest that superoxide binds preferentially to the bridge-free face of the macrocycle. Doubly bridged analogues of the above models were prepared which force the two faces of the porphyrin to be equivalent. Superoxide binding studies indicated a different mode of reactivity to the singly bridged models, for one of the compounds, and experiments to distinguish between possible interpretations of the results are suggested. A crown ether thiolate doubly bridged porphyrin was prepared as a model for the carbon monoxide complex of the enzyme. This was characterised by ultraviolet spectroscopy and attempts to produce a stable crystalline adduct are described. The remaining part of this work concerns a model for the charge separation process in photosynthesis. A discussion of natural systems and previous models is followed by a description of a tetraene pyromellitimide doubly bridged porphyrin, which shows significant quenching of the porphyrin fluorescence.
19
Rogers, Walter L. "Applications of modern control theory synthesis to a super-augmented aircraft." Thesis, Monterey, California. Naval Postgraduate School, 1989. http://hdl.handle.net/10945/26890.
Full text
20
Shabanowitz, Timothy B. (Timothy Brian). "The progressive synthesis of architecture and engineering in modern bridge design." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/34587.
Full textAbstract:
Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2006.Includes bibliographical references (leaves 43-44).
History states that architects and engineers rarely operate in a peaceful environment as each have their own specific agendas to fulfill. The architect appeals to the plastic form of a building before tending to its structural behavior while the engineer tends towards the opposite. While both are striving for a workable structure, their priorities are mismatched. Bridge building, through history usually was considered an engineering feat as it was strictly constructed to traverse a crevasse, waterway or some other obstacle. However through the 20th century, the respective roles have evolved and bridges have become more than a mere span. The architect has revolutionized the art of building a bridge, but was it the technology of the engineer that helped propel the architect or was it just a simple awakening by the architectural community? By analyzing a variety of bridges by Santiago Calatrava and Robert Maillart among other architects and engineers that have been the most influential in this movement, and their construction process, form, materials, and design process, et al., it can be observed how the bridge building process has evolved. Bridge building is an engineering movement no more, but it is not an architectural movement either. In part, by way of these bridge building pioneers, the two professions have started to sideline their angst and ridicule and create a new harmony throughout the built environment.
(cont.) Bridge building is an engineering movement no more, but it is not an architectural movement either. In part, by way of these bridge building pioneers, the two professions have started to sideline their angst and ridicule and create a new harmony throughout the built environment.
by Timothy B. Shabanowitz.
M.Eng.
21
Anderson, R. J. "B1̲2̲ models : Synthesis and reactions." Thesis, University of Newcastle Upon Tyne, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.383946.
Full text
22
Galerne, Bruno. "Stochastic image models and texture synthesis." Phd thesis, École normale supérieure de Cachan - ENS Cachan, 2010. http://tel.archives-ouvertes.fr/tel-00595283.
Full textAbstract:
Cette thèse est une étude de modèles d'image aléatoires avec des applications en synthèse de texture.Dans la première partie de la thèse, des algorithmes de synthèse de texture basés sur le modèle shot noise sont développés. Dans le cadre discret, deux processus aléatoires, à savoir le shot noise discret asymptotique et le bruit à phase aléatoire, sont étudiés. On élabore ensuite un algorithme rapide de synthèse de texture basé sur ces processus. De nombreuses expériences démontrent que cet algorithme permet de reproduire une certaine classe de textures naturelles que l'on nomme micro-textures. Dans le cadre continu, la convergence gaussienne des modèles shot noise est étudiée d'avantage et de nouvelles bornes pour la vitesse de cette convergence sont établies. Enfin, on présente un nouvel algorithme de synthèse de texture procédurale par l'exemple basé sur le récent modèle Gabor noise. Cet algorithme permet de calculer automatiquement un modèle procédural représentant des micro-textures naturelles.La deuxième partie de la thèse est consacrée à l'étude du processus feuilles mortes transparentes (FMT), un nouveau modèle germes-grains obtenu en superposant des objets semi-transparents. Le résultat principal de cette partie montre que, lorsque la transparence des objets varie, le processus FMT fournit une famille de modèles variant du modèle feuilles mortes à un champ gaussien. Dans la troisième partie de la thèse, les champs aléatoires à variation bornés sont étudiés et on établit des résultats généraux sur le calcul de la variation totale moyenne de ces champs. En particulier, ces résultats généraux permettent de calculer le périmètre moyen des ensembles aléatoires et de calculer explicitement la variation totale moyenne des modèles germes-grains classiques.
23
Orsi, Maia. "Population synthesis models for IMF studies." Thesis, Liverpool John Moores University, 2014. http://researchonline.ljmu.ac.uk/4525/.
Full textAbstract:
Population synthesis models (PSMs) are fundamental tools to study the star formation history and IMF of unresolved stellar populations using spectral features. This work presents a new set of PSMs constructed using theoretical isochrones and two state-ofthe- art synthetic spectral libraries. The BT-Settl and Munari libraries were chosen for their ability to predict the observed values of Lick-type and IMF-sensitive indices in individual stars of the solar neighbourhood. The BT-Settl library was used to sample the cool main sequence stars and the Munari library for the rest of the evolutionary phases. The PSMs cover a range of metallicities with [Fe/H]= 0, -1.31 and -1.81 for scaled-solar and α-enhanced metal mixtures. The models were used to study the behaviour of the IMF indices defined in the literature and the results are in good agreement with what other PSMs have determined. The PSMs in this work predict a strong degeneracy between age, metallicity and IMF. I used the models to study which are the main evolutionary phases contributing to each IMF-sensitive index and found that most indices reach their final integrated values before the turn off. The post-main sequence stars contribute mainly to the continuum of these bands. Uncertainties in the the effective temperature of the isochrones can affect IMF estimates. The PSMs were applied to extragalactic globular clusters (GCs) and early-type galaxies (ETGs) using data from the literature. I determined the ages, metallicities and IMFs of these systems using index combinations in the optical and infrared. I explored how the morphology of the Horizontal Branch (HB) and dynamical evolution (which are key uncertainties in the modelling of GCs) can affect the IMF predictions. In a population with a Milky Way IMF, dynamical evolution can make the IMF indices mimic a bottom-light IMF. HB morphology has no impact on the IMF estimates at low [Fe/H]. In the IMF index-index diagrams for GCs, the results are significantly affected by the unknown sodium abundances of these systems. Using the PSMs in this work the best index combination to determine the IMF is CaH1 and TiO2. The ETGs and the [Fe/H]=0 GCs appear to have a bottom-heavy IMF with x ~ 3:0. These results are discussed in the work.
24
Fomumbod, Enni Nina. "Toward the Synthesis of Nuclease Models." Digital Commons @ East Tennessee State University, 2008. https://dc.etsu.edu/etd/1912.
Full textAbstract:
Nucleases are enzymes that can specifically recognize nucleic acids and hydrolyze their phosphodiester bonds effectively. As is the case with many hydrolases, nucleases often carry one or more metal centers. Cooperation between such metal centers and other interactions involving general acid-base activities are believed to be essential in multifunctional catalyses. Combination of such interactions in model compounds often resulted in larger than additive effects.
This work is aimed at synthesizing nuclease models that combine the ability to recognize phosphate groups and/or nitrogen bases of DNA together with the ability to catalyze phosphodiester hydrolysis. These models were designed to achieve optimum interaction between the recognition and the catalytic functionalities. Towards this goal, we chose phenonthiazonium ions (methylene blue analogues) and anthracene as spacers.
25
Sández, Clara. "Synthesis and characterization of molecular models towards PCET studies : Organic Synthesis." Thesis, Uppsala universitet, Molekylär biomimetik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-227744.
Full text
26
Domingues, Joana Andreia Lameiras. "Spectroscopy studies on conservation issues in modern and contemporary paintings." Master's thesis, Faculdade de Ciências e Tecnologia, 2010. http://hdl.handle.net/10362/4480.
Full textAbstract:
Dissertation presented to the Faculty of Sciences and Technology of New University
of Lisbon in fulfilment of the requirements for the Master’s degree in Conservation and Restoration Specialization in easel paintingModern and contemporary paintings are one of today’s grand challenges in conservation of cultural heritage. Particularly, these paintings have often been retouched using materials rather similar to originals, thus, compromising the reversibility of the overpainting. In this work, FTIR and Raman spectroscopies, assisted by optical microscopy, were used to evaluate the effectiveness and harmfulness of chemical and laser cleaning methods for the removal of overpaints. Representative mock-ups prepared with commercial paint formulations were used. The laser cleaning experiment was part of an interdisciplinary study which aims the evaluation of method’s limitations by using the most aggressive cleaning parameters. The combined use of FTIR and Raman spectroscopies could identify constituent materials of modern paints, controlling their behaviour under cleaning, while optical microscopy allowed the evaluation on surface morphology. In addition, equivalent portable equipments from MOLAB were covered as a preparation for in situ analysis. Several problems in the selective removal of overpaints were found with chemical cleaning. The laser cleaning showed better efficiency in removing them, although, some alterations occurred upon laser irradiation, for instance, binder degradation with carbon formation and titanium white alteration. The proposed spectroscopic protocol was considered useful for controlling different cleaning methods in modern and contemporary paintings.
27
Teplechuk, Mykhaylo A. "Design and synthesis of modern integrated filter networks : a computer-aided approach." Thesis, University of Glasgow, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.433275.
Full text
28
Lettiere, Chris, Nat Raimondo, and Tom Macdonald. "GPS and a Modern Data Link Supporting the Synthetic Battlefield." International Foundation for Telemetering, 1996. http://hdl.handle.net/10150/611391.
Full textAbstract:
International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, CaliforniaThis paper describes the use of GPS, a data communication network, and modern simulation techniques to create a synthetic battlefield for testing and training applications. It will discuss recent experiments conducted by the DoD to evaluate this approach.
29
Raad, cisa Lara. "Exemplar based texture synthesis : models and applications." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLN042/document.
Full textAbstract:
Cette thèse s’attaque au problème de la synthèse de texture par l’exemple en utilisant des modèles stochastiques locaux de patchs pour générer de nouvelles images. La synthèse de texture par l’exemple a pour but de générer à partir d’un échantillon de texture de nouvelles images qui sont perceptuellement équivalentes à celle de départ. Les méthodes peuvent se regrouper en deux catégories: les méthodes paramétriques et les non paramétriques à base de patchs. Le premier groupe a pour but de caractériser une image de texture à partir d’un ensemble de statistiques qui définissent un processus stochastique sous-jacent. Les résultats visuels de ces méthodes sont satisfaisants, mais seulement pour un groupe réduit de types de texture. La synthèse pour des images de textures ayant des structures très contrastées peut échouer. La deuxième catégorie d’algorithme découpe, puis recolle de manière consistante des voisinages locaux de l’image de départ pour générer de nouvelles configurations plausibles de ces voisinages (ou patchs). Les résultats visuels de ces méthodes sont impressionnants. Néanmoins, on observe souvent des répétitions verbatim de grandes parties de l’image d’entrée qui du coup peuvent être reproduites plusieurs fois. De plus, ces algorithmes peuvent diverger, reproduisant de façon itérative une partie de l’image de l’entrée en négligeant le reste. La première partie de cette thèse présente une approche combinant des idées des deux catégories de méthodes, sous le nom de synthèse localement Gaussienne. On préserve dans cette nouvelle méthode les aspects positifs de chaque approche: la capacité d’innover des méthodes paramétriques, et la capacité de générer des textures fortement structurées des méthodes non paramétriques à base de patchs. Pour ce faire, on construit un modèle Gaussien multidimensionnel des auto-similarités d’une image de texture. Ainsi, on obtient des résultats qui sont visuellement supérieurs à ceux obtenus avec les méthodes paramétriques et qui sont comparables à ceux obtenus avec les méthodes non-paramétriques à base de patchs tout en utilisant une paramétrization locale de l’image. La thèse s’attache aussi à résoudre une autre difficulté des méthodes à base de patchs: le choix de la taille du patch. Afin de réduire significativement cette dépendance, on propose une extension multi échelle de la méthode. Les méthodes à bases de patchs supposent une étape de recollement. En effet, les patchs de l’image synthétisée se superposent entre eux, il faut donc gérer le recollement dans ces zones. La première approche qu’on a considérée consiste à prendre en compte cette contrainte de superposition dans la modélisation des patchs. Les expériences montrent que cela est satisfaisant pour des images de textures périodiques ou pseudo-périodiques et qu’en conséquence l’étape de recollement peut être supprimée pour ces textures. Cependant, pour des images de textures plus complexes ce n’est pas le cas, ce qui nous a menée à suggérer une nouvelle méthode de recollement inspirée du transport optimal. Cette thèse conclut avec une étude complète de l’état de l’art en génération d’images de textures naturelles. L’étude que nous présentons montre que, malgré les progrès considérables des méthodes de synthèse à base d’exemples proposées dans la vaste littérature, et même en les combinant astucieusement, celles-ci sont encore incapables d’émuler des textures complexes et non stationnairesThis dissertation contributes to the problem of exemplar based texture synthesis by introducing the use of local Gaussian patch models to generate new texture images. Exemplar based texture synthesis is the process of generating, from an input texture sample, new texture images that are perceptually equivalent to the input. There are roughly two main categories of algorithms: the statistics based methods and the non parametric patch based methods. The first one aims to characterize a given texture sample by estimating a set of statistics which will define an underlying stochastic process. The results of this kind of methods are satisfying but only on a small group of textures, failing when important structures are visible in the input provided. The second category methods reorganize local neighborhoods from the input sample in a consistent way creating new texture images. These methods return impressive visual results. Nevertheless, they often yield verbatim copies of large parts of the input sample. Furthermore, they can diverge, starting to reproduce iteratively one part of the input sample and neglecting the rest of it, thus growing ``garbage''. In this thesis we propose a technique combining ideas from the statistic based methods and from the non parametric patch based methods. We call it the locally Gaussian method. The method keeps the positive aspects of both categories: the innovation capacity of the parametric methods and the ability to synthesize highly structured textures of the non parametric methods. To this aim, the self-similarities of a given input texture are modeled with conditional multivariate Gaussian distributions in the patch space. In general, the results that we obtain are visually superior to those obtained with statistic based methods while using local parametric models. On the other hand, our results are comparable to the visual results obtained with the non parametric patch based methods. This dissertation addresses another weakness of all patch based methods. They are strongly dependent on the patch size used, which is decided manually. It is therefore crucial to fix a correct patch size for each synthesis. Since texture images have, in general, details at different scales, we decided to extend the method to a multiscale approach which reduces the strong dependency of the method on the patch size. Patch based methods involve a stitching step. Indeed, the patches used for the synthesis process overlap each other. This overlap must be taken into account to avoid any transition artifact from patch to patch. Our first attempt to deal with it was to consider directly the overlap constraints in the local parametric model. The experiments show that for periodic and pseudo-periodic textures, considering these constraints in the parametrization is enough to avoid the stitching step. Nevertheless, for more complex textures it is not enough, and this led us to suggest a new stitching technique inspired by optimal transport and midway histogram equalization.This thesis ends with an extensive analysis of the generation of several natural textures. This study shows that, in spite of remarkable progress for local textures, the methods proposed in the extensive literature of exemplar based texture synthesis still are incapable of dealing with complex and non-stationary textures
30
Campbell, Wilhelm. "Multi-level speech timing control." Thesis, University of Sussex, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.283832.
Full textAbstract:
This thesis describes a model of speech timing, predicting at the syllable level, with sensitivity to rhythmic factors at the foot level, that predicts segmental durations by a process of accommodation into the higher-level timing framework. The model is based on analyses of two large databases of British English speech; one illustrating the range of prosodic variation in the language, the other illustrating segmental duration characteristics in various phonetic environments. Designed for a speech synthesis application, the model also has relevance to linguistic and phonetic theory, and shows that phonological specification of prosodic variation is independent of the phonetic realisation of segmental duration. It also shows, using normalisation of phone-specific timing characteristics, that lengthening of segments within the syllable is of three kinds: prominence-related, applying more to onset segments; boundary-related, applying more to coda segments; and rhythm/rate-related, being more uniform across all component segments. In this model, durations are first predicted at the level of the syllable from consideration of the number of component segments, the nature of the rhyme, and the three types of lengthening. The segmental durations are then constrained to sum to this value by determining an appropriate uniform quantile of their individual distributions. Segmental distributions define the range of likely durations each might show under a given set of conditions; their parameters are predicted from broad-class features of place and manner of articulation, factored for position in the syllable, clustering, stress, and finality. Two parameters determine the segmental duration . pdfs, assuming a Gamma distribution, and one parameter determines the quantile within that pdf to predict the duration of any segment in a given prosodic context. In experimental tests, each level produced durations that closely fitted the data of four speakers of British English, and showed performance rates higher than a comparable model predicting exclusively at the level of the segment.
31
Faitelson, David. "Program synthesis from domain specific object models." Thesis, University of Oxford, 2008. http://ora.ox.ac.uk/objects/uuid:0c5a992e-dad4-435c-a576-e3ed504bcdbd.
Full textAbstract:
Automatically generating a program from its specification eliminates a large source of errors that is often unavoidable in a manual approach. While a general purpose code generator is impossible to build, it is possible to build a practical code generator for a specific domain. This thesis investigates the theory behind Booster — a domain specific, object based specification language and automatic code generator. The domain of Booster is information systems — systems that consist of a rich object model in which the objects refer to each other to form a complicated network of associations. The operations of such systems are conceptually simple (changing the attributes of objects, adding or removing new objects and creating or destroying associations) but they are tricky to implement correctly. The thesis focuses on the theoretical foundation of the Booster approach, in particular on three contributions: semantics, model completion, and code generation. The semantics of a Booster model is a single abstract data type (ADT) where the invariants and the methods of all the classes in the model are promoted to the level of the ADT. This is different from the traditional view that considers each class as a separate ADT. The thesis argues that the Booster semantics is a better model of object oriented systems. The second important contribution is the idea of model completion — a process that augments the postconditions of methods with additional predicates that follow from the system’s invariant and the method’s original intention. The third contribution describes a simple but effective code generation technique that is based on interpreting postconditions as executable statements and uses weakest preconditions to ensure that the generated code refines its specification.
32
Valsamakis, Nikolas. "Non-standard sound synthesis with dynamic models." Thesis, University of Plymouth, 2013. http://hdl.handle.net/10026.1/2841.
Full textAbstract:
This Thesis proposes three main objectives: (i) to provide the concept of a new generalized non-standard synthesis model that would provide the framework for incorporating other non-standard synthesis approaches; (ii) to explore dynamic sound modeling through the application of new non-standard synthesis techniques and procedures; and (iii) to experiment with dynamic sound synthesis for the creation of novel sound objects. In order to achieve these objectives, this Thesis introduces a new paradigm for non-standard synthesis that is based in the algorithmic assemblage of minute wave segments to form sound waveforms. This paradigm is called Extended Waveform Segment Synthesis (EWSS) and incorporates a hierarchy of algorithmic models for the generation of microsound structures. The concepts of EWSS are illustrated with the development and presentation of a novel non-standard synthesis system, the Dynamic Waveform Segment Synthesis (DWSS). DWSS features and combines a variety of algorithmic models for direct synthesis generation: list generation and permutation, tendency masks, trigonometric functions, stochastic functions, chaotic functions and grammars. The core mechanism of DWSS is based in an extended application of Cellular Automata. The potential of the synthetic capabilities of DWSS is explored in a series of Case Studies where a number of sound object were generated revealing (i) the capabilities of the system to generate sound morphologies belonging to other non-standard synthesis approaches and, (ii) the capabilities of the system of generating novel sound objects with dynamic morphologies. The introduction of EWSS and DWSS is preceded by an extensive and critical overview on the concepts of microsound synthesis, algorithmic composition, the two cultures of computer music, the heretical approach in composition, non- standard synthesis and sonic emergence along with the thorough examination of algorithmic models and their application in sound synthesis and electroacoustic composition. This Thesis also proposes (i) a new definition for “algorithmic composition”, (ii) the term “totalistic algorithmic composition”, and (iii) four discrete aspects of non-standard synthesis.
33
Pradhan, Almitra. "Accurate analog synthesis with circuit matrix models." Cincinnati, Ohio : University of Cincinnati, 2009. http://rave.ohiolink.edu/etdc/view.cgi?acc_num=ucin1258661691.
Full textAbstract:
Thesis (Ph.D.)--University of Cincinnati, 2009.Advisor: Ranga Vemuri. Title from electronic thesis title page (viewed Jan. 19, 2010). Keywords: VLSI; Analog circuit synthesis; Circuit Matrix; Fast model evaluations; Parasitic aware design. Includes abstract. Includes bibliographical references.
34
Koecher, Matthew R. "Hardware Synthesis of Synchronous Data Flow Models." BYU ScholarsArchive, 2004. https://scholarsarchive.byu.edu/etd/20.
Full textAbstract:
Synchronous Dataflow (SDF) graphs are a convenient way to represent many signal processing and dataflow operations. Nodes within SDF graphs represent computation while arcs represent dependencies between nodes. Using a graph representation, SDF graphs formally specify a dataflow algorithm without any assumptions on the final implementation. This allows an SDF model to be synthesized into a variety of implementation techniques including both software and hardware. This thesis presents a technique for generating an abstract hardware representation from SDF models. The techniques presented here operate on SDF models defined structurally within the Ptolemy modeling environment. The behavior of the nodes within Ptolemy SDF models is specified in software and can be simple, such as a single arithmetic operation, or arbitrarily complex. This thesis presents a technique for extracting the behavior of a limited class of SDF nodes defined in software and generating a structural description of the SDF model based on primitive arithmetic and logical operations. This synthesized graph can be used for subsequent hardware synthesis transformations.
35
Warner, Jacqueline Anne. "Examination of biosynthetic models for the formation of prostaglandins and naturally occurring antimalarial compounds." Thesis, The University of Sydney, 1993. https://hdl.handle.net/2123/26630.
Full textAbstract:
The following work investigates two mechanistic proposals for the metal-catalysed reactions of allylic hydroperoxides. A heterolytic mechanism, involving bond migration, and a radical mechanism, involving a peroxy radical intermediate were considered. A study of the cleavage reaction of cyclic allylic hydroperoxides indicated that the outcome was substrate and catalyst dependent. Treatment of the six membered cyclic allylic hydroperoxide 129 with various metal catalysts led to the formation of the aldol 131 as the major product. However, similar treatment of the five-membered cyclic allylic hydroperoxide 130 led to the formation of a variety of indiscriminate products. Further, treatment of the tertiary hydroperoxide 144 with various metal catalysts led to the formation of the epoxy alcohol 155. The results obtained from reactions involving the cleavage of simple cyclic allylic hydroperoxides bear significant similarities with metal-catalysed reactions of hydroperoxides derived from fatty acids and the methyl ester of qinghao acid.
An examination of the involvement of the heterolytic pathway in metal catalysed reactions of qinghao acid methyl ester hydroperoxide 77 was also undertaken. Metal-catalysed reactions involving a presumed enol ether intermediate of the heterolytic pathway were examined under both nitrogen and oxygen. The reactions yielded a variety of products which were found to be solvent dependent. The aldol products 169 were efficiently formed as a result of treatment of the enol ether 158 with copper(II) trifluoromethane sulfonate in dichloromethane/acetonitrile (5:1). In acetonitrile, under prolonged exposure to oxygen, oxygenation products 160 and 178 were observed. Further, it was found that one of the aldol diastereomers 169a underwent oxygenation in the presence of copper(II) trifluoromethane sulfonate to yield the peroxyhemiaceta l 161. A mechanistic pathway for the oxygenation of the aldol 169 via the formation of an oxetanol intermediate was best able to account for the observation that only one aldol diastere omer underwent oxygenat ion.
Low temperature NMR experiments of the cleavage reaction of qinghao acid methyl ester hydroperoxide 77 to the dicarbonyl compound 81 revealed the intermediacy of two distinct intermediates which were identified as the triflyl enol ether acetal 213 resulting from bond migration and, the aldol 207. An oxetanol intermediate was proposed to account for the transformation from the triflyl enol ether acetal 213 to the aldol 207.
Further, an investigatory metal catalysed, intermolecular reaction with ethyl vinyl ether and cyclohexanone led to the formation of a proposed trioxane 200. The formation of such a product implicates the involvement of an electron transfer reaction to generate a radical cation intermediate.
36
Dube, Henry. "Synthetic models for heme proteins /." Zürich : ETH, 2008. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=17641.
Full text
37
Carley, Michael. "Planning in the modern state : a new synthesis and a programme for theory." Thesis, University of British Columbia, 1989. http://hdl.handle.net/2429/41443.
Full textAbstract:
The notion that there is some crisis of public sector planning is common, and a
literature review reveals this concern extends across the social sciences, and even to
the conception and working of the modern welfare state. The dissertation links
political science and philosophy with organisation theory to explain the parameters
and tensions governing planning by the state, and proposes an agenda for liberal
democratic planning theory for the 1990s. It is argued that these notions of crisis
have a common basis in endemic tensions in the modern state which define the
planning context. The instability of this context is heightened by increased
turbulence in organizational relations at all levels and in the world economic system,
and by readjustments in political values reflected in the election of conservative
governments in many countries.
The idea of crisis provides a useful beginning for analysing the problem of planning,
an understanding of which requires a broad view of the socio-political and
epistemoiogical context in which planners operate. The concept of planning crisis is
broken down into constituent parts from which, it is argued, a more profound view of
the context of planning is rebuilt, and from which more appropriate responses to
societal problems are likely to arise. By devising a formulation that generalizes
expectable constraints across various planning situations, an original contribution is
made towards a partial theory of the institutional and professional contexts of
planning action.
First, planning is defined as an instrumental expression of the role of the state in
society which attempts to assert the preeminence of the future in the present, in
terms of control over scarce resources and private property for some greater good fostered by the state. Then the historical and philosophical basis for the role of the
state is discussed in terms of factors which both underlie, and undermine, planning
action: state power and individual freedom, social control for state stability, and the
role of markets in terms of broader social objectives. The problem of planning is
examined in terms of tensions between centre and periphery, economic objectives and
political aspirations, opposing and confused trends to centralization and
decentralization, and inter-organizational conflict and re-adjustment which seems an
inevitable consequence of state intervention in society.
In organisation theory, planning is seen as an attempt to manage change in turbulent
environments characterised by uncertainty, inconsistent and ill-defined values, and an
inability to predict the cumulative consequences of action. Analytic tools for
understanding the planning dilemma are discussed, particularly conceptions of
organizational learning, resources, networks, and capacity to innovate. The
usefulness of static models for understanding dynamic planning situations is
questioned.
The discussion of the crisis of planning is concluded by turning to its epistemoiogical
dimension, termed a crisis of rationality. This refers to the inability of social
scientists to model complex social systems, and their seeming failure to devise theory
useful to social action. The legacy of positivism and the concept of rationality in
planning thought are examined. Three influential planning theories are analysed in
terms of their contribution to an understanding of the crisis of planning and extent to
which they can offer practical guidance.
The conclusion relates the main themes to the current theoretical task, which is to
build up a series of useful, partial, conceptions of the possibility for planning action from a realistic understanding of its socio-political context. It is argued that the
crisis of planning is rooted in the inevitable lack of consensus about the state's role,
and the efficacy of intervention in the workings of the market in terms of human
benefit and social justice. This lack of consensus is also set in a fundamental
relationship to the crisis of rationality.
First, it is argued that planning theorists have a responsibility to explore the
practical implications of organizational options at the state-market conjuncture.
Further, as any conception of the future is an interactive fusion of fact and value,
theorists have a responsibility to develop ethical frameworks and principles, which
may help combine the practical benefits of market mechanisms in terms of feedback
with a conception of the transcending social responsibility of the state and the need
to 'embed' ethical principles in political culture. Second, appropriate organizational
responses to uncertainty are proposed, in particular action learning, inter-agency
ventures, negotiation, cooperation, and risk taking.
Third, the implications for planning theory of the boundaries of social scientific
inquiry are examined, in light of endemic uncertainty, the drive to unified social
theory which distances theoretical abstractions from reality, and the lure of
academic structures and rewards which inhibit the required holistic and
interdisciplinary approach. A policy model is proposed which reflects the centrality
of values in the planning context, the non-revolutionary nature of planning action,
and the position of planning knowledge as a lever on the distribution of societal
power, requiring ethical norms.
In an appendix, analytic elements derived from the work are used in a case study of
urban decline and planning response in the UK.Applied Science, Faculty of
Community and Regional Planning (SCARP), School of
Graduate
38
Rockstroh, Manuel Tobias. "Combustion characteristics of synthetic gasoline in modern charge boosted GDI Engines." Doctoral thesis, University of Cape Town, 2015. http://hdl.handle.net/11427/15715.
Full textAbstract:
Sasols synthetically derived gasoline blending components have traditionally been combined predominantly according to process economics to formulate commercial fuel blends that meet in-house fit-for-purpose requirements and the legislated fuel specifications in South Africa. In this study the potential for optimisation of a fuel blend using full boiling range synthetic blending components to enhance its performance in a modern charge boosted gasoline direct injection engine was investigated. An evaluation of detailed analytical fuel chemistry data was conducted followed by laminar ame speed experiments in a constant-volume combustion bomb apparatus in order to characterise the combustion behaviour of the blending components according to their characteristic chemical properties. A matrix of test fuels was established by splash blending the synthetic components with a commercial synthetic reference fuel. The performance of the fuels was subsequently evaluated using a modern, charge boosted, single cylinder GDI research engine. While the engine operation was verified to be in the negative-K region using model fuel components, anomalies in de fining the K-value using the synthetic blends were discovered. A fuel blending model was composed to allow prediction of linear and non-linear fuel properties of user de fined synthetic blend ratios. By integrating an engine performance test fuel scoring system, the model could be used to de fine optimal fuel blends through selection of a desired performance criterion while constraining the optimisation process to adhere to the national legislated gasoline specifications. Four final fuel blends were optimised according to best power output, gravimetric specific fuel consumption, volumetric specific fuel consumption and specific legislated emissions. A fifth blend was optimised for highest power output with no regard for fuel property specifications other than Reid vapour pressure. The performance of the optimised blends was evaluated on the test engine and the results indicated the potential to positively affect the performance characteristics of a synthetic fuel blend for use in a modern spark ignition engine. This study demonstrates a methodology for optimisation of a synthetic fuel to user-selected performance criteria and it is believed that this work represents a novel and valuable contribution to this field.
39
Stupinský, Šimon. "Pokročilé metody pro syntézu pravděpodobnostních programů." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2021. http://www.nusl.cz/ntk/nusl-445587.
Full textAbstract:
Pravdepodobnostné programy zohrávajú rozhodujúcu úlohu v rôznych technických doménach, ako napríklad počítačové siete, vstavané systémy, stratégie riadenia spotreby energie alebo softvérové produčkné linky. PAYNT je nástroj na automatizovanú syntézu pravdepodobnostných programov vyhovujúcich zadaným špecifikáciam. V tejto práci rozširujeme tento nástroj predovšetkým o podporu optimálnej syntézy a syntézy viacerých špecifikácií. Ďalej sme navrhli a implementovali novú metódu, ktorá dokáže efektívne syntetizovať parametre so spojitým definičným oborom ovplyvňujúce pravdepodobnostné prechody popri syntéze topológie programov, t.j., podporu pre syntézu topológie aj parametrov súčasne. Demonštrujeme užitočnosť a výkonnosť nástroja PAYNT na širokej škále prípadových štúdií z rôznych aplikačných domén ktoré majú uplatnenie v reálnom svete. Pri náročných problémoch syntézy môže PAYNT výrazne znížiť dobu behu až z dní na minúty a zároveň zaistiť úplnosť procesu syntézy.
40
Shannon, Sean Matthew. "Probabilistic acoustic modelling for parametric speech synthesis." Thesis, University of Cambridge, 2014. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.708415.
Full text
41
Baloyi, Ntsako. "A text-to-speech synthesis system for Xitsonga using hidden Markov models." Thesis, University of Limpopo (Turfloop Campus), 2012. http://hdl.handle.net/10386/1021.
Full textAbstract:
Thesis (M.Sc. (Computer Science) --University of Limpopo, 2013This research study focuses on building a general-purpose working Xitsonga speech synthesis system that is as far as can be possible reasonably intelligible, natural sounding, and flexible. The system built has to be able to model some of the desirable speaker characteristics and speaking styles. This research project forms part of the broader national speech technology project that aims at developing spoken language systems for human-machine interaction using the eleven official languages of South Africa (SA). Speech synthesis is the reverse of automatic speech recognition (which receives speech as input and converts it to text) in that it receives text as input and produces synthesized speech as output. It is generally accepted that most people find listening to spoken utterances better that reading the equivalent of such utterances. The Xitsonga speech synthesis system has been developed using a hidden Markov model (HMM) speech synthesis method. The HMM-based speech synthesis (HTS) system synthesizes speech that is intelligible, and natural sounding. This method can synthesize speech on a footprint of only a few megabytes of training speech data. The HTS toolkit is applied as a patch to the HTK toolkit which is a hidden Markov model toolkit primarily designed for use in speech recognition to build and manipulate hidden Markov models.
42
Bratenko, M. K. "Modern organic synthesis of pyrazolo[3,4-e][1,2,3]triazolo[1,5-a]diazepine-3-carboxamides." Thesis, БДМУ, 2020. http://dspace.bsmu.edu.ua:8080/xmlui/handle/123456789/18354.
Full text
43
Root, William. "THE SYNTHESIS OF PROGRAMMED INSTRUCTION AND ONLINE EDUCATION: TOWARDS A MODERN-DAY TEACHING MACHINE." OpenSIUC, 2019. https://opensiuc.lib.siu.edu/dissertations/1735.
Full textAbstract:
The last fifty years have seen rapid growth in student enrollment in online courses. However, few systematic investigations have been utilized to identify best practices in online education experimentally. Skinner (1958) laid out a science of teaching derived from the principles of operant conditioning, and methods for adopting programmed instruction into the evolving technology of his time. In what he termed a "Teaching Machine," automated instruction programmed contingencies for the student with self-paced, carefully designed sequences towards mastery of the material. This series of investigations evaluated the efficacy of programmed instruction in online courses, as measured by quiz performance, the frequency of discussion posts, instructor time commitment, generalization, maintenance, and student perceptions of the online modalities used. The online classrooms were all conducted through Adobe Connect Meeting Software (2017) to include both asynchronous and synchronous online arrangements. Experiment 1 compared the effects of on-campus delivered lectures and online delivered lectures on weekly quiz performance, percentage correct on within assessments forms, the frequency of questions asked, participant preference, and generalization measures. Experiment 2 compared the effects of lectures delivered exclusively online and module packets, designed with components of Skinnerian programmed instruction, on weekly quiz performance, instructor time commitment, participant preference of both experimental conditions, and generalization measures. Experiment 3 compared the effects of online lectures + discussion and module packets + chat on weekly quiz performance, participant preference, and generalization measures. With the increasing demand for university courses delivered exclusively online, results are discussed on the viability of automated, programmed instruction to teach course material exclusively online.
44
Owen, Michael Information Technology & Electrical Engineering Australian Defence Force Academy UNSW. "Temporal motion models for video mosaicing and synthesis." Awarded by:University of New South Wales - Australian Defence Force Academy, 2008. http://handle.unsw.edu.au/1959.4/39028.
Full textAbstract:
Video compression aims to reduce video file size without impacting visual quality. Existing algorithms mostly use transform coders to convert information from the spatial to frequency domain, and attenuate or remove high frequency components from the sequence. This enables the omission of a large proportion of high frequency information with no discernible visual impact. Sprite-based compression encodes large portions of a scene as a single object in the video sequence, recreating the object in subsequent frames by warping or morphing the sprite to mimic changes in subsequent frames. This thesis sought to improve several aspects of existing sprite based compression approaches, employing a temporal motion model using a low order polynomial to represent the motion of an object across multiple frames in a single model rather than a series of models. The main outcome is the demonstration that motion models used by sprite based video compression can be extended to a full three dimensional model, reducing the overall size of the model, and improving the quality of the sequence at low bit rates. A second outcome is the demonstration that super-resolution processing is not necessary if lanczos spatial interpolation is used instead of bilinear or bi-cubic interpolation, resulting in a savings in computational time and resources. A third outcome is the introduction of a new blending model used to generate image mosaics that improves the quality of the synthesised sequence when zoom is present in the sequence for a given bit-rate. A final outcome is demonstrating that performing superresolution processing and sub-sampling back to the original resolution prior to compression provides benefits in some circumstances.
45
Moini, Alireza. "Synthesis of biological vision models using analog VLSI /." Title page, contents and abstract only, 1997. http://web4.library.adelaide.edu.au/theses/09PH/09phm712.pdf.
Full text
46
Theobald, Barry-John. "Visual speech synthesis using shape and appearance models." Thesis, University of East Anglia, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.396720.
Full text
47
Hu, Qiong. "Statistical parametric speech synthesis based on sinusoidal models." Thesis, University of Edinburgh, 2017. http://hdl.handle.net/1842/28719.
Full textAbstract:
This study focuses on improving the quality of statistical speech synthesis based on sinusoidal models. Vocoders play a crucial role during the parametrisation and reconstruction process, so we first lead an experimental comparison of a broad range of the leading vocoder types. Although our study shows that for analysis / synthesis, sinusoidal models with complex amplitudes can generate high quality of speech compared with source-filter ones, component sinusoids are correlated with each other, and the number of parameters is also high and varies in each frame, which constrains its application for statistical speech synthesis. Therefore, we first propose a perceptually based dynamic sinusoidal model (PDM) to decrease and fix the number of components typically used in the standard sinusoidal model. Then, in order to apply the proposed vocoder with an HMM-based speech synthesis system (HTS), two strategies for modelling sinusoidal parameters have been compared. In the first method (DIR parameterisation), features extracted from the fixed- and low-dimensional PDM are statistically modelled directly. In the second method (INT parameterisation), we convert both static amplitude and dynamic slope from all the harmonics of a signal, which we term the Harmonic Dynamic Model (HDM), to intermediate parameters (regularised cepstral coefficients (RDC)) for modelling. Our results show that HDM with intermediate parameters can generate comparable quality to STRAIGHT. As correlations between features in the dynamic model cannot be modelled satisfactorily by a typical HMM-based system with diagonal covariance, we have applied and tested a deep neural network (DNN) for modelling features from these two methods. To fully exploit DNN capabilities, we investigate ways to combine INT and DIR at the level of both DNN modelling and waveform generation. For DNN training, we propose to use multi-task learning to model cepstra (from INT) and log amplitudes (from DIR) as primary and secondary tasks. We conclude from our results that sinusoidal models are indeed highly suited for statistical parametric synthesis. The proposed method outperforms the state-of-the-art STRAIGHT-based equivalent when used in conjunction with DNNs. To further improve the voice quality, phase features generated from the proposed vocoder also need to be parameterised and integrated into statistical modelling. Here, an alternative statistical model referred to as the complex-valued neural network (CVNN), which treats complex coefficients as a whole, is proposed to model complex amplitude explicitly. A complex-valued back-propagation algorithm using a logarithmic minimisation criterion which includes both amplitude and phase errors is used as a learning rule. Three parameterisation methods are studied for mapping text to acoustic features: RDC / real-valued log amplitude, complex-valued amplitude with minimum phase and complex-valued amplitude with mixed phase. Our results show the potential of using CVNNs for modelling both real and complex-valued acoustic features. Overall, this thesis has established competitive alternative vocoders for speech parametrisation and reconstruction. The utilisation of proposed vocoders on various acoustic models (HMM / DNN / CVNN) clearly demonstrates that it is compelling to apply them for the parametric statistical speech synthesis.
48
Ziyuan, Jiang. "Synthesis of GPU Programs from High-Level Models." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-230163.
Full textAbstract:
Modern graphics processing units (GPUs) provide high-performance general purpose computation abilities. They have massive parallel architectures that are suitable for executing parallel algorithms and operations. They are also throughput-oriented devices that are optimized to achieve high throughput for stream processing. Designing efficient GPU programs is a notoriously difficult task. The ForSyDe methodology is suitable to ease the difficulties of GPU programming. The methodology encourages software development from a high level of abstraction and then transforming the abstract model to an implementation through a series of formal methods. The existing ForSyDe models support the synchronous data flow (SDF) model of computation (MoC) which is suitable for modeling stream computations and is good for synthesizing efficient stream processing programs. There also exists high-level design models named parallel patterns that are suitable to represent parallel algorithms and operations. The thesis studies the method of modeling parallel algorithms using parallel patterns, and explores the way to synthesize efficient OpenCL implementation on GPUs for parallel patterns. The thesis also tries to enable the integration of parallel patterns into the ForSyDe SDF model in order to model stream parallel operations. An automation library that helps designing stream programs for parallel algorithms targeting GPUs is purposed in the thesis project. Several experiments are performed to evaluate the effectiveness of the proposed library regarding implementations of the high-level model.Moderna grafikbehandlingsenheter (GPU) tillhandahåller högpresterande generella syftes-beräkningsförmågor. De har massiva parallella arkitekturer som är lämpliga för att utföra parallella algoritmer och operationer. De är också streaminriktade enheter som är optimerade för att uppnå hög streaming för streamingbehandling. Att utforma effektiva GPU-program är en notoriskt svårt uppgift. ForSyDe-metoden är lämplig för att underlätta svårigheterna med GPU-programmering. Metodiken uppmuntrar mjukvaruutveckling från en hög nivå av abstraktion för att sedan omvandla den abstrakta modellen till en implementering genom en rad formella metoder. De befintliga ForSyDe-modellerna stöder synkron dataflöde (SDF) modell av beräkning (MoC) som är lämplig för modellering av streaming-beräkningar och är bra för att syntetisera effektiv streaming-bearbetningsprogram. Det finns också högkvalitativa designmodeller som kallas parallella mönster vilka är lämpliga för att representera parallella algoritmer och operationer. Avhandlingen analyserar metoden för modellering av parallella algoritmer med parallella mönster, och utforskar sättet att syntetisera effektiv OpenCL-implementering för GPU för parallella mönster. Avhandlingen försöker även att möjliggöra integration av parallella mönster i ForSyDe SDF-modellen för att modellera streaming parallella operationer. Ett automationsbibliotek som hjälper till att designa stream-program för parallella algoritmer som riktar sig mot GPU:er är avsedda för avhandlingsprojektet. Flera experiment utförs för att utvärdera effektiviteten hos det föreslagna biblioteket avseende implementering av högnivåmodellen.
49
Mattes, Symeon. "Perceptual models for sound field analysis and synthesis." Thesis, University of Southampton, 2016. https://eprints.soton.ac.uk/397216/.
Full textAbstract:
This thesis describes the methodology that has been followed for the implementation of a biologically inspired auditory signal processing model that predicts human sound localization of stationary acoustic sound sources in 3D space. The intended use of the the model is for the evaluation of audio systems. An attempt is made to develop both a theoretical and mathematical framework that can be adopted as a generalized theory for the development of biologically inspired models of human sound localization. The model makes use of a combination of monaural and binaural cues and within a psychoacoustical framework makes predictions of the location of a sound source given the sound presence signals delivered to the ears. Finally, the effectiveness of the model is evaluated through comparison with the experimental results of a listening test in which a number of human subjects made judgements of the location of real sound sources in 3D space under anechoic conditions.
50
Kite, Brett Lee. "Synthesis of Crowded Tolanes: Models for Molecular Recognition." Diss., Virginia Tech, 2005. http://hdl.handle.net/10919/26433.
Full textAbstract:
The development of suitable models to study and quantify the strengths of noncovalent interactions is a major goal of our group. With this goal in mind, we have synthesized octasubstituted diarylacetylenes (tolanes) as potential model systems to measure intramolecular noncovalent interactions.
The Stille cross-coupling reaction allowed synthesis of both arylacetylenes and tolanes from aryl iodides. The Stille reaction is usually slow for electron rich aryl iodides (such as these aryl iodides that are substituted resorcinol derivatives). However, these crowded penta-substituted aryl iodides underwent the Stille coupling reactions (typically 2-3 hours) at a significantly faster rate than the Stille couplings of the un-crowded tri-substituted aryl iodides (typically 24 hours). DFT calculations on 1,3-dimethoxy-2-iodobenzene (as a model system) indicate that this rate difference is mainly due to a decrease in the reduction potential of the crowded penta-substituted aryl iodides (~ 0.4 eV lower) relative to the tri-substituted aryl iodides.
The successful synthesis of the targeted crowded symmetrical tetra ester produced a mixture of atropomers, which separated into two components with similar NMR and MS data. HF calculations on 4,4',6,6'-tetra-tert-butyl-1,1',3,3'-tetramethoxydiphenylacetylene (as a model system) showed that there are five possible atropomeric conformations. We separated the component which showed a green fluorescence when irradiated with UV (254 nm) light and grew a suitable single crystal. The X-ray crystal structure revealed that this component is the syn-syn_anti atropomer. The remaining atropomers, which show blue fluorescence when irradiated with UV (254 nm) light, were not successfully separated. Comparison of the observed UV spectrum of the green-fluorescent atropomer (syn-syn_anti) with a calculated (ZINDO) UV spectrum of diphenylacetylene, with an interplanar angle of 0° between the arene rings, showed that the observed and calculated spectra closely matched. The calculated (ZINDO) UV spectrum of diphenylacetylene, with an interplanar angle of 60° between the arene rings, closely matched the observed spectrum for the blue-fluorescent component (mixture of atropomers). The combination of experimental and computational methods demonstrated the stereochemical complexities of the crowded symmetrical tetra ester.Ph. D.