996 resultados para Evolutionary operators


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The future global distribution of the political regimes of countries, just like that of their economic incomes, displays a surprising tendency for polarization into only two clubs of convergence at the extrema. This, in itself, is a persuasive reason to analyze afresh the logical validity of an endogenous theory for political and economic development inherent in modernization theory. I suggest how adopting a simple evolutionary game theoretic view on the subject allows an explanation for these parallel clubs of convergence in political regimes and economic income within the framework of existing research in democratization theory. I also suggest how instrumental action can be methodically introduced into such a setup using learning strategies adopted by political actors. These strategies, based on the first principles of political competition, are motivated by introducing the theoretical concept of a Credible Polity.

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In this chapter we examine a number of methods to construct aggregation operators of interpolatory type for specific applications. The construction is based on the desired values of the aggregation operator at certain prototypical points, and on other desired properties, such as, conjuctive, disjunctive or averaging behaviour, symmetry and marginals.

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This chapter provides a review of various techniques for identification of weights in generalized mean and ordered weighted averaging aggregation operators, as well as identification of fuzzy measures in Choquet integral based operators. Our main focus is on using empirical data to compute the weights. We present a number of practical algorithms to identify the best aggregation operator that fits the data.

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A fundamental issue in biology is explaining the diversity of coloration found in nature. Birds provide some of the best-studied examples of the evolution and causes of color variation and some of the most arresting color displays in the natural world. They possess perhaps the most richly endowed visual system of any vertebrate, including UV-A sensitivity and tetrachromatic color vision over the 300-700-nm waveband. Birds provide model systems for the multidisciplinary study of animal coloration and color vision. Recent advances in understanding avian coloration and color vision are due to recognition that birds see colors in a different way than humans do and to the ready availability of small spectrometers. We summarize the state of the current field, recent trends, and likely future directions.

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Polymerase chain reaction (PCR) sequencing of specific viral gene segments was used to investigate the phylogenetic relationships among the orbiviruses. Sequence comparisons of the bluetongue virus (BTV) RNA3 from different regions of the world (North America, South Africa, India, Indonesian, Malaysia, Australia and the Caribbean region) showed that geographic separation had resulted in significant divergence, consistent with the evolution of distinct viral populations. There were at least 3 topotypes (Gould, 1987); the Australasian, African - American and another topotype represented by BTV 15 isolated in Australia in 1986. The topotypes of BTV had RNA3 nucleotide sequences that differed by approximately 20 per cent. Analysis of BTV-specific gene segments from animal and insect specimens showed that bluetongue viruses had entered northern Australia from South East Asia, possibly by wind-borne vectors. Nucleotide sequence comparisons were used to show the close genetic relationship between BTV 2 (Ona-A strain) from Florida and BTV 12 from Jamaica, and to investigate the reassortment of BTV genome segments in nature. The mutation rates of the BTV RNA2 and RNA3 segments were estimated to be of the order of 10(-4) nucleotide changes/site/year, similar in magnitude to that reported for other RNA viruses.

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The theory of ‘punctuated equilibria’ was formulated by two paleontologists, Niles Eldredge and Stephen Gould, in 1972 and has been the focus of considerable controversy within the evolutionary sciences ever since. The primary intentions of this thesis are to relate the history of punctuated equilibria and to examine how it has affected evolutionary science. Several modes of analysis have been used to illuminate the history: The sociological perspectives of Pierre Bourdieu and Bruno Latour (who see scientific debate as a ‘struggle for authority’); Rhetorical analysis of some of the key documents; Communication with practising scientists via questionnaires and correspondence; Citation Analysis. Chapter 1 gives a short summary of the history and introduces the methods and socio-philosophical perspectives used to illuminate the history. Chapters 3 and 4 examine the rhetorical process by which Eldredge and Gould constructed the ‘punctuationist revolution’. Chapters 2, 3, 5 and 6 relate the history of punctuated equilibria.

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This thesis examined genetic variation among populations of galaxiid fish of different life histories. Evidence of incipient speciation was found among several landlocked populations; however, little genetic differentiation was found among Australian coastal populations. Evidence was found to suggest a marine ancestry for galaxiids and several taxonomic revisions were suggested.

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We consider the use of Ordered Weighted Averaging (OWA) in linear regression. Our goal is to replace the traditional least squares, least absolute deviation, and maximum likelihood criteria with an OWA function of the residuals. We obtain several high breakdown robust regression methods as special cases (least median, least trimmed squares, trimmed likelihood methods). We also present new formulations of regression problem. OWA-based regression is particularly useful in the presence of outliers.

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We consider an application of fuzzy logic connectives to statistical regression. We replace the standard least squares, least absolute deviation, and maximum likelihood criteria with an ordered weighted averaging (OWA) function of the residuals. Depending on the choice of the weights, we obtain the standard regression problems, high-breakdown robust methods (least median, least trimmed squares, and trimmed likelihood methods), as well as new formulations. We present various approaches to numerical solution of such regression problems. OWA-based regression is particularly useful in the presence of outliers, and we illustrate the performance of the new methods on several instances of linear regression problems with multiple outliers.

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In this paper we provide a systematic investigation of a family of composed aggregation functions which generalize the Bonferroni mean. Such extensions of the Bonferroni mean are capable of modeling the concepts of hard and soft partial conjunction and disjunction as well as that of k-tolerance and k-intolerance. There are several interesting special cases with quite an intuitive interpretation for application.

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In this work we propose an image reduction algorithm based on weak local reduction operators. We use several averaging functions to build these operators and we analyze their properties. We present experimental results where we apply the algorithm and weak local reduction operators in procedures of reduction, and later, reconstruction of images. We analyze these results over natural images and noisy images.

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Despite a growing acceptance of the value of evolutionary approaches to understanding the natural world there has been relatively little attention paid to evolutionary ideas in sociology, socio-cultural anthropology, and — of particular relevance for this special issue — criminology and forensic/correctional psychology. The aim of this paper is to provide an introductory overview of evolutionary approaches to human behavior with a focus on illuminating the role they can play in enriching our understanding of criminal and antisocial behavior. We begin with an overview of the main approaches to applying evolutionary theory to human behavior and we suggest that a pluralistic perspective is most likely to advance conceptual and empirical work in the field. We then turn to a brief discussion of some common, but misguided criticisms of this approach. Some of the more substantive conceptual and methodological issues that evolutionary approaches need to address are then explored. Finally, we engage with the broader issues that relate to the role of evolutionary explanations in the social and behavioral sciences.