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Polimerização de eteno em altas pressões e temperaturas utilizando catalisadores níquel-alfa-diiminaMartini, Denise dos Santos January 2005 (has links)
O complexo 1,4-bis(2,6-diisopropilfenil)-acenaftenodiimina-dicloroníquel(II) (1), em combinação com metilaluminoxano (MAO) foi utilizado para polimerizar eteno utilizando altas pressões e temperaturas. Foram investigados os efeitos da pressão de eteno, da temperatura, do tempo de reação e da quantidade de catalisador bem como, as propriedades dos polietilenos sintetizados. Os polietilenos obtidos com o sistema (1)/MAO foram altamente ramificados. As ramificações variaram de metil até hexil ou até mais longas, sem adição de comonômero. Os polietilenos não apresentaram metilas isoladas, apresentando uma grande quantidade de metilas 1,4, metilas 1,5 e metilas 1,6 e cadeias longas. A presença de ramificações foi devido ao mecanismo denominado chain-walking. Os valores de ramificações nos PE foram maiores que 105 e menores que 277 ramificações/1000C. O aumento do número de ramificações foi devido ao aumento na temperatura de polimerização e uma diminuição da pressão de eteno. Os PE obtidos com o sistema (1)/MAO apresentaram peso molecular (Mw) elevado entre 44.000 e 105.000 Daltons e valores de polidispersão de 2,0 a 4,0, dependendo das condições reacionais. O peso molecular dos polímeros diminuiu com o aumento da temperatura de polimerização. / The combination of 1,4-bis(2,6-diisopropylphenyl)-acenaphthenediiminedichloronickel( II) (1) and methylaluminoxane (MAO) was highly active in ethylene polymerization under high pressures and temperatures. Herein we investigated the effects of ethylene pressure, reaction temperature, reaction time and amount of catalyst on polymer properties and reaction performance. The polyethylenes obtained with 1/MAO are highly branched. The branches goes from methyl to hexyl or even longer, and this without comonomer addition. These polyethylenes obtained do not shows isolated methyl groups, but shows 1,4-methyl, 1,5 and 1,6 methyl patterns. The branching was due to the so-called chain-walking mechanism. The branch content, which is in the range 105 to 277 branches/1000 C, increased with the temperature rising or the ethylene concentration decrease. The polyethylenes produced with these system have molecular weight between 44.000 and 105.000 Daltons and polydispersions from 2,0 to 4,0 depending on the reactions conditions. The polymer molecular weight tended to decrease with increasing polymerization temperature.
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Polimerização de eteno em altas pressões e temperaturas utilizando catalisadores níquel-alfa-diiminaMartini, Denise dos Santos January 2005 (has links)
O complexo 1,4-bis(2,6-diisopropilfenil)-acenaftenodiimina-dicloroníquel(II) (1), em combinação com metilaluminoxano (MAO) foi utilizado para polimerizar eteno utilizando altas pressões e temperaturas. Foram investigados os efeitos da pressão de eteno, da temperatura, do tempo de reação e da quantidade de catalisador bem como, as propriedades dos polietilenos sintetizados. Os polietilenos obtidos com o sistema (1)/MAO foram altamente ramificados. As ramificações variaram de metil até hexil ou até mais longas, sem adição de comonômero. Os polietilenos não apresentaram metilas isoladas, apresentando uma grande quantidade de metilas 1,4, metilas 1,5 e metilas 1,6 e cadeias longas. A presença de ramificações foi devido ao mecanismo denominado chain-walking. Os valores de ramificações nos PE foram maiores que 105 e menores que 277 ramificações/1000C. O aumento do número de ramificações foi devido ao aumento na temperatura de polimerização e uma diminuição da pressão de eteno. Os PE obtidos com o sistema (1)/MAO apresentaram peso molecular (Mw) elevado entre 44.000 e 105.000 Daltons e valores de polidispersão de 2,0 a 4,0, dependendo das condições reacionais. O peso molecular dos polímeros diminuiu com o aumento da temperatura de polimerização. / The combination of 1,4-bis(2,6-diisopropylphenyl)-acenaphthenediiminedichloronickel( II) (1) and methylaluminoxane (MAO) was highly active in ethylene polymerization under high pressures and temperatures. Herein we investigated the effects of ethylene pressure, reaction temperature, reaction time and amount of catalyst on polymer properties and reaction performance. The polyethylenes obtained with 1/MAO are highly branched. The branches goes from methyl to hexyl or even longer, and this without comonomer addition. These polyethylenes obtained do not shows isolated methyl groups, but shows 1,4-methyl, 1,5 and 1,6 methyl patterns. The branching was due to the so-called chain-walking mechanism. The branch content, which is in the range 105 to 277 branches/1000 C, increased with the temperature rising or the ethylene concentration decrease. The polyethylenes produced with these system have molecular weight between 44.000 and 105.000 Daltons and polydispersions from 2,0 to 4,0 depending on the reactions conditions. The polymer molecular weight tended to decrease with increasing polymerization temperature.
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Uso de cortes canonicos no metodo de ramificação local para problemas inteiros 0-1 mistos / Use of canonical cuts in the local branching method for mixed 0-1 integerSantos, Rafael Francisco dos 21 December 2006 (has links)
Orientador: Cid Carvalho de Souza / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Computação / Made available in DSpace on 2018-08-08T14:02:44Z (GMT). No. of bitstreams: 1
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Previous issue date: 2006 / Resumo: Nesta dissertação propomos um uso mais geral dos Cortes Canônicos (CCs) introduzidos por Balas e Jeroslow ([2]) no método de Ramificação Local (RamLoc) de Fischetti e Lodi ([6]). A ramificação local é uma heurística de propósito geral para Programação Inteira Mista (MIP) que explora vizinhanças definidas através da adição de inequações lineares ao modelo original. Estas inequações determinam subproblemas que são computados mais rapidamente pelos resolvedores de MIP. Uma análise da execução da RamLoc indicou que, em algumas situações, ela acrescenta cortes de ramificação local muito superficiais (i.e.,que descartam poucas soluções) e que estes cortes ocorrem com grande freqüência. Como os cortes de ramificações locais de Fischetti e Lodi são casos especiais dos CCs para programação inteira 0?1, n'os propomos a incorporação de CCs mais profundos (i.e.,que descartam mais soluções) à RamLoc. Executamos o algoritmo resultante sobre 25 das 29 instâncias testadas em [6] e obtivemos melhores resultados do aqueles alcançado pela RamLoc original e pelo resolvedor comercial de MIP XPRESS com seus parâmetros default. Uma outra investigação que empreendemos foi a inclusão dos CCs na heurística para modelos gerais de programação inteira mista RINS ([3]). Esta heurística surgiu durante o desenvolvimento desta dissertação e apresentou um bom desempenho. Realizamos alguns testes com as mesmas instâncias sobre as quais a RamLoc foi executada e obtivemos resultados promissores. Por fim, além da utilização dos CCs em heurísticas, criamos uma estratégia de ramificação que pode ser embutida nos algoritmos de branch-and-cut dos resolvedores de MIP. Denominamos esta estratégia de dive branching e a implementamos no resolvedor XPRESS. Em experimentos conduzidos com o mesmo conjunto de instâncias anteriores, obtivemos resultados de melhor qualidade do que aqueles produzidos pelo XPRESS com seus parâmetros default / Abstract: In this dissertation we propose a broader usage of the Canonical Cuts (CC) introduced by Balas and Jeroslow ([2]) in the Local Branching method (LB) of Fischetti and Lodi ([6]). The LB is a general purpose heuristic for Mixed Integer Programming (MIP) that explores neighborhoods defined by the addition of linear inequalities to the original model. These inequalities determine subproblems that are computed more quickly by MIP solvers. An analysis of the execution of LB indicated that, in some situations, it adds local branching cuts that are too superficial (i.e., chopping off few solutions) and that these cuts happen very often. Since the local branching cuts of Fischetti and Lodi are special cases of CCs for 0?1 integer programming, we propose to incorporate deeper CCs (i.e, chopping of more solutions) to LB. We executed the resulting algorithm on 25 out of the 29 instances tested in [6] and we obtained better results than those attained by the original LB and by the XPRESS commercial MIP solver under default settings. Another research that we carried out was the inclusion of CC to the RINS heuristics for general mixed integer programs ([3]). This heuristic appeared during the development of this dissertation and showed a good performance. We carried out some tests with the same instances on which LB was tested and the results are promising. Finally, besides using the CCs in heuristics, we created a branching strategy that can be embedded to the branch-and-cut algorithms of the MIP solvers. We called it dive branching and implemented it in the XPRESS solver. In experiments with the same set of instances as before, we obtained results of better quality than those produced by XPRESS with default settings / Mestrado / Mestre em Ciência da Computação
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Evaluate methods for managing distributed source changesLaitala, Christer January 2008 (has links)
In larger developments, a use of configuration management is crucial; the company UIQ Technology is no exception. The configuration management method controls how the flow within a software developer should go, so the configuration management method and code complexity is something that works affects each other. Therefore, you might be able to combine multiple configuration methods to try to use the best from each method to decrease code complexity. That is the goal of this thesis, to see if the COTS, Single repository or Component Based could combine with the UIQ method to decrease code complexity. This have been tested through theoretical use cases for each method and the conclusion of the study is that, Single repository and Component Based works best in the UIQ method. However, COTS is not suited for the UIQ method because of the need of secrecy for large parts of the UIQ platform. UIQ wants to do as much as possible in-house, rather than give it out to other third-party companies that they are not in absolute need of. Some improvements have been achieved throughout Single repository, that the other third-parties companies needs to be upto- date before starting development, that is something that have not been valued before.
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EVOLUTIONARY AI IN BOARD GAMES : An evaluation of the performance of an evolutionary algorithm in two perfect information board games with low branching factorÖberg, Viktor January 2015 (has links)
It is well known that the branching factor of a computer based board game has an effect on how long a searching AI algorithm takes to search through the game tree of the game. Something that is not as known is that the branching factor may have an additional effect for certain types of AI algorithms. The aim of this work is to evaluate if the win rate of an evolutionary AI algorithm is affected by the branching factor of the board game it is applied to. To do that, an experiment is performed where an evolutionary algorithm known as “Genetic Minimax” is evaluated for the two low branching factor board games Othello and Gomoku (Gomoku is also known as 5 in a row). The performance here is defined as how many times the algorithm manages to win against another algorithm. The results from this experiment showed both some promising data, and some data which could not be as easily interpreted. For the game Othello the hypothesis about this particular evolutionary algorithm appears to be valid, while for the game Gomoku the results were somewhat inconclusive. For the game Othello the performance of the genetic minimax algorithm was comparable to the alpha-beta algorithm it played against up to and including depth 4 in the game tree. After that however, the performance started to decline more and more the deeper the algorithms searched. The branching factor of the game may be an indirect cause of this behaviour, due to the fact that as the depth increases, the search space increases proportionally to the branching factor. This increase in the search space due to the increased depth, in combination with the settings used by the genetic minimax algorithm, may have been the cause of the performance decline after that point.
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Contribution au dépliage des réseaux de Petri et à l’analyse des processus de branchement / Contribution to the unfolding of Petri nets and to the analysis of branching processComlan, Maurice 03 November 2016 (has links)
Les réseaux de Petri et leurs extensions constituent un formalisme très connu pour la modélisation de la spécification des systèmes à évènements discrets temps réel. Pour ces systèmes, les exigences de vérification et de validation sont indispensables pour garantir leur bon fonctionnement car la moindre erreur peut entrainer des conséquences catastrophiques. Pour analyser le comportement du système, il est courant de construire le graphe d’états (ou espace d’états) qui énumère de façon exhaustive les différents états accessibles.Ce graphe permet de vérifier des propriétés génériques comme le caractère borné, l’accessibilité, la terminaison, la vivacité, l’absence de blocage, etc. Mais la construction de cet espace d’états est confrontée au problème d’explosion combinatoire du nombre d’états lié à la complexité et à la concurrence du système.L’une des alternatives pour contenir cette combinatoire est de conserver uniquement les ordres partiels entre les évènements. Le dépliage est une technique d’ordre partiel adaptée à la vérification, au diagnostic et à la planification. Cette thèse contribue à l’étude du dépliage des réseaux de Petri et, plus particulièrement,apporte une contribution au dépliage des réseaux de Petri avec des arcs de reset. De plus, le dépliage explicite les exécutions possibles du système qui sont, par définition, des processus. Il s’agit plus précisément des processus de branchement qui diffèrent des processus classiques. Ainsi, nous proposons une algèbre adaptée aux processus de branchement issus du dépliage des réseaux de Petri. / Petri nets and their extensions are a well-known formalism for modeling the specification of discrete events systems real-time. For these systems, the demands of verification and validation are essential to ensure their smooth functioning because the least error can lead to catastrophic consequences. To analyze the behavior of the system, it is common to construct the stategraph (or state space) which lists exhaustively the different accessible states. This graph allows to check the generic properties such as boundedness, accessibility, termination, vivacity, the absence of blocking, etc. But building this state space is confronted with the problem of combinatorial explosion of the number of states related to the complexity and concurrence of the system. One of the alternatives to contain this combination is to keep only partial orders between events. Unfolding is a partial order adapted to technical verification, diagnosis and planning. This thesis contributes to the study of the unfolding of Petri nets and, in particular, his contributes to the unfolding of Petri nets with reset arcs. Moreover, the unfolding explains the possible executions of the system which are, by definition, the processes. This is specifically the branching processes that differ from conventional processes. Thus, we propose an algebra adapted to the branching process from unfolding of Petri nets.
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Relatedness, Industrial Branching and Technological Cohesion in US Metropolitan AreasEssletzbichler, Jürgen January 2015 (has links) (PDF)
Relatedness, industrial branching and technological cohesion in US metropolitan areas, Regional Studies. Work by evolutionary economic geographers on the role of industry relatedness for regional economic development is extended into a number of methodological and empirical directions. First, relatedness is measured as the intensity of inputoutput linkages between industries. Second, this measure is employed to examine industry evolution in 360 US metropolitan areas. Third, an employment-weighted measure of metropolitan technological cohesion is developed. The results confirm that technological relatedness is positively related to metropolitan industry portfolio membership and industry entry and negatively related to industry exit. The decomposition of technological cohesion indicates that the selection of related incumbent industries complements industry entry and exit as the main drivers of change in metropolitan technological cohesion.
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Marches aléatoires branchantes et champs Gaussiens log-corrélés / Branching random walks and log-correlated Gaussian fieldsMadaule, Thomas 13 December 2013 (has links)
Nous étudions le modèle de la marche aléatoire branchante. Nous obtenons d'abord des résultats concernant le processus ponctuel formé par les particules extrémales, résolvant ainsi une conjecture de Brunet et Derrida 2010 [36]. Ensuite, nous établissons la dérivée au point critique de la limite des martingales additives complétant ainsi l'étude initiée par Biggins [23]. Ces deux travaux reposent sur les techniques modernes de décompositions épinales de la marche aléatoire branchante, originairement développées par Chauvin, Rouault et Wakolbinger [41], Lyons, Pemantle et Peres [74], Lyons [73] et Biggins et Kyprianou [24]. Le dernier chapitre de la thèse porte sur un champ Gaussien log-correle introduit par Kahane 1985 [61]. Via de récents travaux comme ceux de Allez, Rhodes et Vargas [11], Duplantier, Rhodes, Sheeld et Vargas [46] [47], ce modèle a connu un important regain d'intérêt. La construction du chaos multiplicatif Gaussien dans le cas critique a notamment été prouvée dans [46]. S'inspirant des techniques utilisées pour la marche aléatoire branchante nous résolvons une conjecture de [46] concernant le maximum de ce champ Gaussien. / We study the model of the branching random walk. First we obtain some results concerning thepoint process formed by the extremal particles, proving a Brunet and Derrida's conjecture [36] as well. Thenwe establish the derivative of the additive martingale limit at the critical point, completing the study initiatedby Biggins [23]. These two works rely on the spinal decomposition of the branching random walk, originallyintroduced by Chauvin, Rouault and Wakolbinger [41], Lyons, Pemantle and Peres [74], Lyons [73] and Bigginsand Kyprianou [24].The last chapter of the thesis deals with a log-correlated Gaussian field introduced by Kahane [61]. Thismodel was recently revived in particular by Allez, Rhodes and Vargas [11], and Duplantier, Rhodes, Shefield andVargas [46] [47]. Inspired by the techniques used for branching random walk we solved a conjecture of Duplantier,Rhodes, Shefield and Vargas [46], on the maximum of this Gaussian field.
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Kinetics and Reaction Mechanisms for Methylidyne Radical Reactions with Small HydrocarbonsRibeiro, Joao Marcelo Lamim 07 November 2016 (has links)
The chemical evolution with respect to time of complex macroscopic mixtures such as interstellar clouds and Titan’s atmosphere is governed via a mutual competition between thousands of simultaneous processes, including thousands of chemical reactions. Chemical kinetic modeling, which attempts to understand their macroscopic observables as well as their overall reaction mechanism through a detailed understanding of their microscopic reactions and processes, thus require thousands of rate coefficients and product distributions. At present, however, just a small fraction of these have been well-studied and measured; in addition, at the relevant low temperatures, such information becomes even more scarce. Due to the recent developments in both theoretical kinetics as well as in ab initio electronic structure calculations, it is now possible to predict accurate reaction rate coefficients and product distributions from first-principles at various temperatures, often in less time, than through the running of an experiment. Here, the results of a first principles theoretical investigation into both the reaction rate coefficients as well as the final product distributions for the reactions between the ground state CH radical (X2Π) and various C1-C3 hydrocarbons is presented; together, these constitute a set of reactions important to modeling efforts relevant to mixtures such as interstellar clouds and Titan’s atmosphere.
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Rôle des strigolactones dans le développement de l’architecture aérienne de la plante en interaction avec les autres hormones végétales / Strigolactones role in plants shoot development in interaction with other hormonesLigerot, Yasmine 04 December 2015 (has links)
La croissance et le développement des plantes sont sous l’influence de nombreux facteurs génétiques et environnementaux. Parmi eux les hormones végétales participent aux multiples processus qui conduisent à la formation d’une plante via la mise en place d’un réseau complexe d’interactions et de rétro-contrôles. Le contrôle de la ramification implique trois d’entre-elles : l’auxine et les strigolactones (SLs) qui inhibent le démarrage des bourgeons et les cytokinines (CKs) qui le stimulent. Différents mécanismes d’interactions entre ces signaux dans le contrôle de la ramification sont connus. L’auxine contrôle les niveaux de SLs et de CKs, et les voies SLs et CKs convergent vers la même cible, le facteur de transcription BRC1.Chez le pois, les mutants hyper-ramifiés ramosus (rms) sont affectés dans la voie SLs. Les gènes RMS1 (PsMAX4) et RMS5 (PsMAX3) contrôlent la biosynthèse des SLs alors que RMS3 (PsD14) (récepteur) et RMS4 (PsMAX2) sont impliqués dans la perception des SLs. En plus de partager un phénotype hyper-ramifié, les mutants rms présentent un phénotype de nanisme. Cependant le rôle des SLs dans le contrôle de la taille des plantes n’était pas encore connu. Nous avons montré que les SLs contrôlent la taille des plantes en jouant sur le processus de division cellulaire indépendamment de la voie gibbérelline.Les mutants rms montrent des caractéristiques physiologiques similaires : un haut niveau d’expression des gènes de biosynthèse des SL et une faible teneur en CKs dans la sève xylémienne (X-CKs). En revanche, le mutant hyper-ramifié rms2 présente une faible expression des gènes de biosynthèse des SLs et une forte teneur en X-CKs. De précédentes études suggèrent que rms2 est affecté dans un signal tige-racine de rétro-contrôle régulant la biosynthèse des SLs et le niveau de X-CKs. La nature biochimique de ce signal est inconnue et il a été proposé que ce signal soit auxine-indépendant.Nous avons montré que le gène RMS2 est l’homologue chez le pois des gènes AFB4/5 d’Arabidopsis codant pour une protéine à boîte-F de la famille des récepteurs de l’auxine TIR1/AFBs (Auxin signaling F-Box). Ce qui suggère que le signal de rétro-contrôle RMS2-dépendant est l’auxine. De plus nos résultats montrent que les SLs jouent un rôle de répresseur du niveau d’auxine dans la tige via la régulation de l’expression des gènes du métabolisme de l’auxine.L’ensemble de ces résultats montrent que dans le processus de contrôle de la ramification les interactions entre auxine et SLs sont complexes. Les multiples mécanismes en jeux aboutissent à la formation d’une boucle de régulation dans laquelle chaque hormone est capable de contrôler la biosynthèse de l’autre. / The different processes of plant growth and development are under the influence of growth regulators which interact in complex hormonal networks and feedback mechanisms. The control of shoot branching involves 3 key plant hormones, auxin, cytokinins (CKs) and strigolactones (SLs). Auxin and SLs repress axillary bud outgrowth whereas CKs stimulate it. Different mechanisms of interactions between these signals have already been suggested in controlling shoot branching. Auxin controls SLs and CKs levels, and SLs and CKs pathways converge on the same target, the TCP transcription factor BRC1 in the axillary bud. In pea, the high shoot branching of ramosus (rms) mutants are known for being impaired in the SLs pathway. RMS1 (PsMAX4) and RMS5 (PsMAX3) genes are involved in SL biosynthesis while RMS3 (PsD14) (receptor) and RMS4 (PsMAX2) are involved in SL perception. In addition to sharing their high branching phenotype, the rms mutants display a dwarf phenotype. However the role of SLs in controlling plant height was unknown. Here we show that SLs control internode length by acting on cell division in a Gibberellin-independent way.The rms mutants show similar physiological characteristics: high expression of the SL-biosynthesis genes and very low xylem-sap CKs (X-CKs) content. In contrast, the rms2 mutant with similar shoot phenotype shows very low expression of SL-biosynthesis genes and high X-CKs content. Previous studies suggested that rms2 was affected in a shoot-to-root feedback signal controlling both SL biosynthesis and X-CKs level. Whether this feedback signal was auxin or not was highly discussed. Here we demonstrated that the RMS2 gene is the pea homologue of the Arabidopsis AFB4/5 gene, encoding an F-box protein which belongs to the TIR1/AFB (Auxin signaling F-Box) auxin receptor family. This suggests that the RMS2-dependent feedback signal is very likely auxin. Moreover our results suggest a role for SLs in the repression of auxin content in pea stem via the regulation of auxin metabolism gene expression. These results highlighted that for the control of shoot branching, interactions between auxin and strigolactones involve multiple mechanisms leading to regulation loop where both hormones are able to regulate the biosynthesis of each other.
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