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UMA ANÁLISE EMPÍRICA DOS DETERMINANTES DAS EXPORTAÇÕES BRASILEIRAS POR SETOR E POR DESTINO (1999-2013) / AN EMPIRICAL ANALYSIS OF THE DETERMINANTS OF BRAZILIAN EXPORTS BY SECTOR AND BY DESTINATION (1999-2013)Casagrande, Dieison Lenon 10 March 2014 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This study aims to analyze the performance of Brazilian exports, disaggregated by
aggregate factor (Basic, Semi-manufactured and Manufactured), to Asia and Trade Partners
NAFTA and the European Union, based on monthly data for the period January 1999 to June
2013. For this, were identified based on theoretical grounds, the main determinants and, through
statistical tools, equations of short and long run for Brazilian sector exports were estimated, so
that they could evaluate the elasticities quantum exported from the country. Still, were analyzed
the performance and structure of Brazilian exports sector, their relationships with selected trade
partners as well as their participation in world trade. For this, from an extension of the
traditional theoretical model of imperfect substitutes, elaborated by Goldstein and Khan (1978),
we use the method of Johansen cointegration and Error Correction Model (ECM) for
determining the elasticities. Through the traditional literature of foreign trade, it was inferred
that the determinants of exports are pegged to an index of income from trading partners, to
index relative price of exports and the exchange rate. The results showed that the elasticities
are greater than the long term to short term. Facing the sectorial impacts, the elasticities of trade
with Asia and NAFTA show that the class of basic goods is more sensitive to income, while
the other classes are more sensitive to exchange rate variations. On the other hand, exports to
the European Union, income is the main determinant of the classes of manufactured and semimanufactured
goods, while basics goods are more sensitive to exchange rates. In reference to
average sectorial elasticities, one can say that income is the main determinant of basic products
exports, while the classes of semi-manufactured and manufactured goods are more sensitive to
changes in price levels. Finally, the negative effect of exchange rate volatility, verified is be a
dynamic mainly short run. / O presente estudo tem como objetivo analisar o desempenho das exportações brasileiras,
desagregadas por fator agregado (Básicos, Semimanufaturados e Manufaturados), para a Ásia
e os Blocos Econômicos Nafta e União Europeia, a partir de dados mensais para o período de
janeiro de 1999 a junho de 2013. Para isso, foram identificados, com base nos fundamentos
teóricos, os principais determinantes e, através do ferramental estatístico, foram estimadas
equações de curto e longo prazo para as exportações setoriais brasileiras, para que se pudesse
avaliar as elasticidades do quantum exportado do país. Ainda, foram analisados o desempenho
e a estrutura das exportações setoriais brasileiras, suas relações com os parceiros comerciais
selecionados, bem como sua participação no comércio mundial. Para tanto, a partir de uma
extensão do tradicional modelo teórico de substitutos imperfeitos, elaborado por Goldstein e
Khan (1978), utiliza-se o método de cointegração de Johansen e o Modelo de Correção de Erros
(ECM) para a determinação das elasticidades. Através da literatura tradicional de comércio
exterior, inferiu-se que os determinantes das exportações estão atrelados a um índice de renda
dos parceiros comerciais, ao índice de preço relativo das exportações e a taxa de câmbio. Os
resultados mostraram que as elasticidades de longo prazo são superiores às de curto prazo.
Frente aos impactos setoriais, as elasticidades do comércio com a Ásia e o Nafta mostram que
a classe de produtos básicos é mais sensível à renda, enquanto que as demais classes são mais
sensíveis às variações cambiais. Por outro lado, nas exportações para a União Europeia, a renda
é o principal determinante das classes de manufaturados e semimanufaturados, enquanto que
os produtos básicos são mais sensíveis ao câmbio. Em referência às elasticidades setoriais
médias, pode-se dizer que a renda é o principal determinante das exportações de produtos
básicos, enquanto que as classes de semimanufaturados e manufaturados são mais sensíveis às
variações dos níveis de preços. Por fim, quanto ao impacto negativo da volatilidade cambial,
verificou-se ser uma dinâmica, principalmente, de curto prazo.
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Les éco-industries : théorie de la firme et politiques optimalesSans, Damien 20 November 2017 (has links)
Cette recherche s'intéresse à la modélisation des éco-industries et aux propriétés qui leurs sont généralement attribuées. Précisément, mettre l'accent sur les éco-industries requiert de faire des suppositions dont les conséquences ne sont pas triviales. Ce travail détaille ces conséquences ainsi que la pertinence de certaines. Le premier chapitre considère des éco-industries polluantes, alors que l'analyse économique sur ce sujet assume généralement que les biens et services environnementaux suppriment les polluants. Ce chapitre montre le mécanisme par lequel le marché distribue une activité aux éco-industries en fonction de leur technologie. Le deuxième chapitre enquête sur les limites à supposer une allocation de pollution positive à la solution optimale alors qu'une élimination complète serait possible. L'exemple de l'amiante montre qu'il existe des situations où la pollution-zéro est préférable à un niveau positif. Ce chapitre montre sous quelles conditions ce postulat est vrai. Le troisième travail se concentre sur la notion de services environnementaux. Ce chapitre montre que ceux-ci sont parfaitement substituables aux autorisations de polluer. L'Etat peut donc sélectionner le prix des services environnementaux et il devient possible d'établir une allocation optimale des ressources même en présence de compétition imparfaite. Enfin, le dernier chapitre détaille une supposée fusion entre un pollueur et son fournisseur de biens et services environnementaux. Il montre les répercussions de la fusion sur une firme non-intégrée et amène une discussion sur la différence entre réduction de la pollution en procédé-intégré ou en bout-de-chaîne. / This research focuses on the modeling of ecoindustries and the properties commonly assigned to them. Precisely, highlighting ecoindustries requires the making of some assumptions with nontrivial consequences. This work uncovers these consequences as well as the adequacy of some of them.The first chapter considers polluting ecoindustries, although economic analysis on the subject generally assumes that environmental goods and services suppress the pollutants. This chapter shows mechanisms through which the market distributes economic activity to ecoindustries according to their technology.The second chapter investigates the limits of supposing a positive pollution allocation at the optimal solution although complete suppression is feasible. The example of asbestos shows that there are situations in which zero-pollution is preferred to a positive amount. The chapter shows the conditions under which this hypothesis is true.The third work focuses on the concept of environmental services. This chapter shows that environmental services and pollution allowances are perfect substitutes, then the government can decide on their prices so that it is possible to decentralize a first-best allocation of resources even in the presence of imperfect competition.Finally, the last chapter details a fictional fusion between a polluter and its environmental goods and services supplier. It shows the consequences of such fusion on an unintegrated firm and opens a discussion on the difference between process-integrated and end-of-pipepollution abatement.
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Modelagem de dados de sistemas reparáveis com fragilidade / Modeling repairable systems data with fragilityFeitosa, Cirdêmia Costa 15 September 2015 (has links)
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Previous issue date: 2015-09-15 / Não recebi financiamento / The usual models in repairable systems are minimal, perfect and imperfect repair, and, in the literature, the minimum repair model is the most explored. In repairable systems it is common that the same type of components are studied and in these cases is relevant to verify the heterogeneity between them. According to Vaupel et al. (1979), the standard methods for analysis of repairable systems data ignore the heterogeneity not observed and in some cases this should be considered. Such variability can be estimated from frailty models, characterized by using a random e ect. It is proposed that the minimum repair model with frailty in order to estimate the heterogeneity not observed between systems. For this model it was conducted a simulation study in order to analyze the frequentist properties of the estimation process. The application of a real data set showed the applicability of the proposed model, in which the estimation of the parameters were determined from maximum likelihood and Bayesian approaches. / Os modelos de sistemas reparáveis usuais são os de reparo mí nimo, perfeito e imperfeito, sendo que, na literatura, o modelo de reparo mí nimo e o mais explorado. Em sistemas reparáveis e comum que componentes do mesmo tipo sejam estudados e nestes casos é relevante verifi car a heterogeneidade entre eles. Segundo Vaupel et al. (1979), os métodos padrões em análise de dados de sistemas reparáveis ignoram a heterogeneidade não observada e em alguns casos esta deveria ser considerada. Tal variabilidade pode ser estimada a partir dos modelos de fragilidade, caracterizados pela utilização de um efeito aleat ório. Propõe-se o modelo de reparo mí nimo com fragilidade, a fi m de estimar a heterogeneidade não observada entre sistemas. Para este modelo foi realizado um estudo de simula ção com o objetivo de analisar as propriedades frequentistas do processo de estimação. A aplicação em um conjunto de dados reais mostrou a aplicabilidade do modelo proposto, em que a estima ção dos parâmetros foram determinadas a partir das abordagens de m áxima verossimilhan ça e Bayesiana.
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A express?o do condicionado contrafactual em constru??es se p, ent?o q no portugu?s brasileiroBrito, Nara Jaqueline Avelar 03 February 2014 (has links)
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Previous issue date: 2014-02-03 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / Neste trabalho, tomamos como objeto de estudo a express?o da fun??o contrafactual
presente em constru??es do tipo se p, ent?o q , com foco no uso alternado de formas
verbais na estrutura??o da ap?dose/condicionado, cujo valor ? canonicamente designado
pelo futuro do pret?rito. Trabalhamos com amostras de fala extra?das de reportagens
televisivas veiculadas na televis?o brasileira entre os anos de 2010 e 2013. A base te?ricometodol?gica
para nossa discuss?o adv?m dos princ?pios do Sociofuncionalismo (cf.
TAVARES, 2003, 2011, 2013; GORSKI; TAVARES, 2013; entre outros) que, por sua vez,
trabalha na interface entre os pressupostos do Funcionalismo lingu?stico (cf. GIV?N,
2001; BYBEE, 2010; entre outros) e da Sociolingu?stica (cf. WEINRICH; LABOV;
HERZOG, 1968; LABOV, 2008 [1972], 2001, 2010; entre outros). Averiguamos
contextos lingu?sticos e extralingu?sticos pass?veis de influenciar a escolha do falante pelo
futuro do pret?rito ou pelo pret?rito imperfeito, tanto em suas formas simples quanto em
locu??es ou formas perifr?sticas. Para tanto, partimos da hip?tese de que fatores
lingu?sticos como a ordem da senten?a e o paralelismo, e de que fatores sociais como o
sexo e o n?vel de escolaridade sejam relevantes para a explica??o do uso alternado de
formas verbais na codifica??o da indica??o contrafactual. Os resultados obtidos em nossa
an?lise (qualitativa e quantitativa) apontam a relev?ncia de alguns desses fatores no uso
efetivo das formas verbais futuro do pret?rito e do pret?rito imperfeito do indicativo nas
ap?doses contrafactuais, e ressaltam o papel de princ?pios funcionalistas (a exemplo do
princ?pio da marca??o e do princ?pio da iconicidade) sobre o uso vari?vel das formas
verbais sob enfoque
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Análise da garantia estendida para equipamentos hospitalares: uma abordagem via teoria dos jogos e processo de renovação generalizadoZAIDAN, Henrique Pinto dos Santos 19 February 2016 (has links)
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Previous issue date: 2016-02-19 / CAPEs / A terceirização da manutenção e a adesão da garantia estendida para equipamentos
hospitalares tem se tornado uma tendência ao longo das últimas décadas, pois estão
relacionadas com a crescente complexidade e modernização dos dispositivos médicos,
bem como, com a recorrente prática da exclusividade do fabricante na realização da
manutenção. Geralmente, o relacionamento entre a instituição de saúde e o fabricante é
conduzido por meio de um documento, especificando questões como: nível de
confiabilidade, desempenho operacional, disponibilidade, duração da garantia, preço da
manutenção, penalidades e a política de manutenção a ser implementada. Sendo assim, a
presente dissertação estuda quantitativamente o problema de garantia estendida para
equipamentos hospitalares, por meio da junção de duas ferramentas: o jogo de
Stackelberg, designado para estruturar a forma de relacionamento entre as empresas, e o
Processo de Renovação Generalizado, responsável processo de falha – reparo do
equipamento (reparo imperfeito). Um cenário foi criado para a aplicação de tais métodos.
Inicialmente, o fabricante ao vender um equipamento hospitalar também oferece duas
possibilidades para a execução da manutenção: a primeira, garantia estendida, e a
segunda, serviço sob demanda. Posteriormente, a decisão do hospital é influenciada pela
estrutura de preços imposta do fabricante, a confiabilidade do equipamento e o seu grau
de aversão ao risco, visto que as falhas do dispositivo são eventos aleatórios. Para ilustrar
tal situação, realiza-se um exemplo numérico com dados de falha e reparo de um
Angiográfo. O equilíbrio do modelo implica na maximização do lucro esperado do
fabricante e o hospital decidindo pela adesão da garantia estendida. Adicionalmente,
comparando as soluções do reparo imperfeito com os cenários de reparos perfeito e
mínimo, observou-se similaridade nas estratégias para os casos de reparos imperfeito e
perfeito, enquanto que, na relação entre os reparos imperfeito e mínimo as estratégias darse-
ão de maneira oposta. Finalmente, o lucro esperado do fabricante diminui conforme
aumenta o número médio de falhas. / The outsourcing of maintenance and the acquisition of extended warranty for hospital
equipment has become a trend over the past few decades, since they are related to the
growing complexity, modernization of medical devices and the recurring practice of the
manufacturer's exclusivity in performing maintenance services. Generally, the
relationship between the health institution and the manufacturer is conducted through a
document specifying the following issues: level of reliability, operating performance,
availability, warranty period, maintenance price, penalties and maintenance policy to be
implemented. Under these circumstances, this thesis analyzes the problem of the extended
warranty for clinical equipment by joining two tools: the Stackelberg game, designed to
model the relation between companies and the Generalized Renewal Process, employed
for modeling failure-repair process (imperfect repair). A scenario was created for the
application of such methods. Initially, the manufacturer intends to sell a medical
equipment and also offers two maintenance possibilities: first, an extended warranty, and
second, maintenance services on demand. Subsequently, the hospital's decision is
influenced by manufacturer's price structure, equipment reliability and the degree of risk
aversion, since the failures occurrences of the device are random events. To illustrate this
situation, an application example with failure and repair data of an Angiography
equipment is presented. The equilibrium of model implies in expected profit
maximization for the manufacturer and hospital chooses the extended warranty option. In
addition, by comparing the solutions of the imperfect repair with perfect and minimal
repair scenarios, a similarity in the strategies adopted in cases of imperfect and perfect
repairs was observed, while the strategies were opposite when comparing imperfect and
minimal repairs. Finally, the expected profit of the manufacturer decreases as the average
number of failures increases.
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O uso do pretérito perfeito e imperfeito em português como língua segunda na Universidade de Dalarna, Suécia.Eriksson, Karin January 2017 (has links)
O presente trabalho tem como primeiro objetivo investigar como os estudantes de português como língua segunda na Universidade de Dalarna usam o pretérito perfeito e imperfeito em textos escritos livremente e em quais contextos gramaticais ocorrem os eventuais erros. Além disso, é observado o grau de uso ou não-uso dos estudantes de advérbios temporais e/ou expressões temporais quando constroem sentenças/frases com o pretérito perfeito e imperfeito. De forma sumária é apresentado como os estudos em Português Língua Segunda estão organizados na Universidade de Dalarna e, seguidamente, é discutido o conceito "aspecto". A parte sobre a metodologia mostra como o estudo, tanto quantitativo como qualitativo, é realizado. Depois de um comentário sobre alguns termos conceptuais apresento um breve resumo das principais características de alguns estudos anteriores sobre "estudar uma segunda língua", tal como uma apresentação sumária de quatro dissertações de mestrado sobre o uso de pretérito perfeito e imperfeito em Português Língua Segunda, tal como o uso ou não uso de advérbios temporais. Na terceira parte os resultados do estudo são apresentados; resultados que mostram que os estudantes da Universidade de Dalarna têm um bom tratamento do pretérito perfeito e imperfeito, mas ocorrem erros. A maioria dos erros é cometida nos seguintes contextos : a) pretérito perfeito simples: uma ação já concluída antes do momento de fala e b) pretérito imperfeito: acontecimento habitual que ocorreu repetidamente no passado, podendo ser periódico ou contínuo. Nos outros dois contextos, pretérito imperfeito: um acontecimento no passado que não se prolonga até o presente e pretérito imperfeito: acontecimentos simultâneos ocorridos no passado, se constata um elevado grau de usos corretos. 3 Quanto ao uso de advérbios temporais e/ou expressões temporais, pode-se notar uma tendência, nomeadamente que os alunos que constroem sentenças corretas com o pretérito perfeito e imperfeito, utilizam advérbios temporais num grau mais elevado do que os estudantes que produzem construções incorretas. Os erros são discutidos na parte qualitativa e por fim, na quarta e última parte, condenso algumas considerações finais. / The present study aims at studying the way students of Portuguese as a second language at the University of Dalarna in Sweden handle two of the past forms, that is, the preterite and the imperfect, in texts written freely and in what grammatical contexts the errors, if any, are committed. The study also takes into consideration to what extent the students use, or do not use, of adverbs of time and/or temporal expressions when constructing sentences/phrases with the preterite or the imperfect. In a summary way I present how the studies in Portuguese as a second language at the University of Dalarna are organized and I also, briefly, discuss the concept of "aspect". In the part about methodology is shown how the present study, which is partly quantitative, partly qualitative, is constructed. After a short discussion regarding some conceptual definitions, a short overview of the most important traits in some earlier studies about studying a second language is given and I also present some authors’ theses about the use of the preterite and the imperfect in Portuguese as a second language, as well as the use or non-use of adverbs of time. In part three of the study the results are presented; results which show that the students at the University of Dalarna handle the two forms in a skilful way but errors do occur. The majority of the errors are committed in the following contexts: a) the preterite: completed action in the past and b) the imperfect: frequency or habit. In the other two contexts studied, namely imperfect: past action of a certain duration and imperfect: two simultaneous actions, the amount of errors is very low. Regarding the use of adverbs of time, a tendency, however a bit vague, can be observed. The students who produce correct sentences with the preterite and the imperfect, show a more frequent use of temporal adverbs and expressions than those students who commit mistakes when using the above mentioned verb forms. The errors committed are discussed in the qualitative part of the essay, and in the fourth and last part of the essay I present some final comments.
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Groupe de Picard des groupes unipotents sur un corps quelconque / Picard groups of unipotent algebraic groups over an arbitrary fieldAchet, Raphaël 25 September 2017 (has links)
Soit k un corps quelconque. Dans cette th±se, on étudie le groupe de Picard des k-groupes algébriques unipotents (lisses et connexes).Tout k-groupe algébrique unipotent est extension itérée de formes du groupe additif; on va donc d'abord s'intéresser au groupe de Picard des formes du groupe additif. L'étude de ce groupe est faite avec une méthode géométrique qui permet de traiter le cas plus général des formes de la droite affine. On obtient ainsi une borne explicite sur la torsion du groupe de Picard desformes de la droite affine et sur la torsion de la composante neutre du foncteur de Picard de leur complétion régulière. De plus, on trouve une condition suffisante pour que le groupe de Picard d'une forme de la droite affinesoit non trivial et on construit des exemples de formes non triviales de la droite affine dont le groupe de Picard est trivial.Un k-groupe algébrique unipotent est une forme de l'espace affine. Afin d'étudier le groupe de Picard d'une forme X de l'espace affine avec une méthode géométrique, on définit un foncteur de Picard "restreint". On montre que si X admet une complétion régulière, alors le foncteur de Picard "restreint" est représentable par un k-groupe unipotent (lisse, non nécessairement connexe).Avec ce foncteur de Picard "restreint" et des raisonnements purement géométriques, on obtient que le groupe de Picard d'une forme unirationnelle de l'espace affine est fini. De plus, on généralise un résultat dû à B. Totaro: si k est séparablement clos, et si le groupe de Picard d'un k-groupe algébrique unipotent commutatif est non trivial, alors il admet une extension non triviale par le groupe multiplicatif. / Let k be any field. In this Ph.D. dissertation we study the Picard group of the (smooth connected) unipotent k-algebraic groups.As every unipotent algebraic group is an iterated extension of forms of the additive group, we will study the Picard group of the forms of the additive group. In fact we study the Picard group of forms of the additive group and the affine line simultaneously using a geometric method. We obtain anexplicit upper bound on the torsion of the Picard group of the forms of the affine line and their regular completion, and a sufficient condition for the Picard group of a form of the affine line to be nontrivial. We also give examples of nontrivial forms of the affine line with trivial Picard groups.In general, a unipotent k-algebraic group is a form of the affine n-space. In order to study the Picard group of a form X of the affine n-space with a geometric method, we define a "restricted" Picard functor; we show that if X admits a regular completion then the "restricted" Picard functor is representable by a unipotent k-algebraic group (smooth, not necessarly connected). With this "restricted" Picard functor and geometric arguments we show that the Picard group of a unirational form of the affine n-space is finite. Moreover we generalise a result of B. Totaro: if k is separablyclosed and if the Picard group of a unipotent k-algebraic group is nontrivial then it admits a nontrivial extension by the multiplicative group.
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An Advanced Skyline Approach for Imperfect Data Exploitation and Analysis / Modèle Skyline pour l'analyse et l'exploitation des données incertainesElmi, Saïda 15 September 2017 (has links)
Ce travail de thèse porte sur un modèle de requête de préférence, appelée l'opérateur Skyline, pour l'exploitation de données imparfaites. L'imperfection de données peut être modélisée au moyen de la théorie de l'évidence. Ce type de données peut être géré dans des bases de données imparfaites appelées bases de données évidentielles. D'autre part, l'opérateur skyline est un outil puissant pour extraire les objets les plus intéressants dans une base de données.Dans le cadre de cette thèse, nous définissons une nouvelle sémantique de l'opérateur Skyline appropriée aux données imparfaites modélisées par la théorie de l'évidence. Nous introduisons par la suite la notion de points marginaux pour optimiser le calcul distribué du Skyline ainsi que la maintenance des objets Skyline en cas d'insertion ou de suppression d'objets dans la base de données.Nous modélisons aussi une fonction de score pour mesurer le degré de dominance de chaque objet skyline et définir le top-k Skyline. Une dernière contribution porte sur le raffinement de la requête Skyline pour obtenir les meilleurs objets skyline appelés objets Etoile ou Skyline stars. / The main purpose of this thesis is to study an advanced database tool named the skyline operator in the context of imperfect data modeled by the evidence theory. In this thesis, we first address, on the one hand, the fundamental question of how to extend the dominance relationship to evidential data, and on the other hand, it provides some optimization techniques for improving the efficiency of the evidential skyline. We then introduce efficient approach for querying and processing the evidential skyline over multiple and distributed servers. ln addition, we propose efficient methods to maintain the skyline results in the evidential database context wben a set of objects is inserted or deleted. The idea is to incrementally compute the new skyline, without reconducting an initial operation from the scratch. In the second step, we introduce the top-k skyline query over imperfect data and we develop efficient algorithms its computation. Further more, since the evidential skyline size is often too large to be analyzed, we define the set SKY² to refine the evidential skyline and retrieve the best evidential skyline objects (or the stars). In addition, we develop suitable algorithms based on scalable techniques to efficiently compute the evidential SKY². Extensive experiments were conducted to show the efficiency and the effectiveness of our approaches.
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Evolution of Mimicry and Aposematism Explained: Salient Traits and Predator PsychologyKazemi, Baharan January 2017 (has links)
Aposematic species have evolved conspicuous warning signals, such as bright colors and striking patterns, to deter predators. Some edible and harmless species take advantage of this deterrent effect by mimicking their appearance. Mimicry is a great example of how natural selection produces remarkable adaptations. However, while some species evolve a very close similarity to their models to effectively avoid attacks, others are successful in doing so despite an incomplete similarity, i.e. imperfect mimicry. In some cases, it is surprising how such a crude disguise can fool predators. Why and how imperfect mimicry can persist has been much discussed and considered as a problem for the theory of natural selection. It is therefore of great interest to understand what makes it possible. Predator psychology is an important factor in the evolution of aposematism and mimicry. In the past decades it has been suggested that certain components of prey appearance are more important to predators than others during prey assessment. We developed this idea by incorporating concepts from associative learning, and presented a new approach to explain imperfect mimicry. Our general hypothesis is that prey traits have different salience to predators. Certain traits are perceived as highly salient and are thus used primarily in the discrimination and generalization of prey, while traits with low salience are overshadowed and not used in the assessment. The salience of a trait can depend on how conspicuous or discriminable it is in the particular context, and can vary due to for example previous predator experience. We tested our ideas with wild blue tits and domestic chickens as predators, and artificial and semi-natural prey stimuli. In paper I we found that the trait that was perceived as most salient (color) was the one used to discriminate and generalize between prey. Mimics of that specific trait were highly avoided, despite differences in the other traits. We also found that salience is relative and context dependent (paper II). In a context where two traits were perceived as similarly salient, mimicry of a single trait offered intermediate protection, while mimicry of both offered high protection. In another context, the traits were perceived differently salient, and mimicry of one trait was enough for high protection. In paper III we tested a proposed scenario for the initiation of mimicry evolution in the edible butterfly mimic Papilio polyxenes asterius to its noxious model Battus philenor. The results showed that a partial similarity with the model in the salient black wing color offered intermediate protection from attacks, despite a general dissimilarity. This thesis investigates the major questions of imperfect mimicry: the initial step of mimicry evolution, the persistence of imperfect mimicry, and variation in mimic-model similarity. We conclude that mimicry evolution can begin in a non-mimetic species that acquires similarity to a model species in a high-salience trait. When multiple traits have similar salience, multi-trait mimicry is needed for higher protection. Mimicry can remain imperfect if the differences are in traits with low salience, and therefore under low or no selection pressure to change. To complete the picture, we showed that predators can have a biased generalization toward a more pronounced version of a salient trait (paper IV). The evolution of aposematism could therefore be explained by gradual enhancement of salient traits. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Accepted. Paper 4: Manuscript.</p>
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Řešení koncovek ve velkých hrách s neúplnou informací jako je např. Poker / Solving Endgames in Large Imperfect-Information Games such as PokerHa, Karel January 2016 (has links)
Title: Solving Endgames in Large Imperfect-Information Games such as Poker Author: Bc. Karel Ha Department: Department of Applied Mathematics Supervisor: doc. Mgr. Milan Hladík, Ph.D., Department of Applied Mathematics Abstract: Endgames have a distinctive role for players. At the late stage of games, many aspects are finally clearly defined, deeming exhaustive analysis tractable. Specialised endgame handling is rewarding for games with perfect information (e.g., Chess databases pre-computed for entire classes of endings, or dividing Go board into separate independent subgames). An appealing idea would be to extend this approach to imperfect-information games such as the famous Poker: play the early parts of the game, and once the subgame becomes feasible, calculate an ending solution. However, the problem is much more complex for imperfect information. Subgames need to be generalized to account for information sets. Unfortunately, such a generalization cannot be solved straightaway, as it does not generally preserve optimality. As a consequence, we may end up with a far more exploitable strategy. There are currently three techniques to deal with this challenge: (a) disregard the problem entirely; (b) use a decomposition technique, which sadly retains only the same quality; (c) or formalize improvements of...
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