En la tesi s'aborda el problema de l'homogeneïtat d'estil en el Tirant lo Blanc mitjançant l'ús de l'estilometria. Les hipòtesis al voltant de l'autoria del Tirant lo Blanc van des de l'autoria única de Joanot Martorell a la intervenció d'un segon autor, be a l'última part de la novel·la o be al llarg de tota ella, passant per altres teories més heterodoxes. A la primera part de la tesi es fa un breu repàs dels problemes que aborda l'estilometria i d'algunes eines estadístiques útils a l'hora de fer un estudi quantitatiu de l'estil literari, es resumeix la qüestió de l'autoria del Tirant lo Blanc, i es descriu la base de dades que s'ha construït per la quantificació de l'estil en el Tirant. Per atacar el problema, hem començat adaptant tècniques d'anàlisi descriptiva de dades, com els gràfics de control i l'anàlisi de correspondències. Per explotar la base de dades, proposem un mètode pràctic per estimar un o més d'un punt de canvi en seqüències de normals, de binomials i de multinomials. El mètode es basa en l'ajust de models i troba els estimadors màxim versemblants del(s) punt(s) de canvi. També hem utilitzat un mètode cluster basat en l'ajust de models per a dades politòmiques, per a agrupar les files d'una taula de contingència. Vam començar l'estudi fent un estudi comparatiu de 12 maneres diferents de mesurar la riquesa i diversitat de vocabulari. Pel que fa a les unitats lexicomètriques la llargada de paraula i l'ús de paraules freqüents i lliures del context ens han sigut molt útils per a l'estimació del punt de canvi i l'atribució d'estil als capítols. L'ús de lletres, tot i ser menys útil, serveix per a reforçar l'evidència del que trobem amb les unitats abans esmentades. La llargada de frase i la de capítol no ens ha sigut útils per a determinar una frontera d'estil en el Tirant.Per tot el que hem anat trobant estem convençuts que hi ha un canvi sobtat en l'estil entre els capítols 371 i 382, que difícilment pot ser atribuïble a l'argument. També hem trobat que després del punt de canvi conviuen capítols amb els dos estils, el que probablement reforça la teoria de que un segon autor va afegir capítols sobre un original pràcticament acabat. De totes maneres, no ens pertoca a nosaltres descobrir que el canvi d'estil no pugui ser degut a altres raons. / En la tesis se aborda el problema de la homogeneidad de estilo en el Tirant lo Blanc mediante el uso de la estilometría. Las hipótesis sobre la autoría del Tirant lo Blanc van desde la autoría única de Joanot Martorell a la intervención de un segundo autor, bien en la última parte de la novela o bien a lo largo de toda ella, pasando por otras teorías más heterodoxas. En la primera parte de la tesis se hace un breve repaso de los problemas que aborda la estilometría i de algunas herramienta estadísticas útiles para el estudio cuantitativo del estilo literario, se resume la cuestión de la autoría del Tirant lo Blanc, y se describe la base de datos que s ha construido para la ciantificación del estilo en el Tirant. Para atacar el problema, hemos empezado adaptando técnicas de análisis descriptivo de datos, como los gráficos de control y el análisis de correspondencias. Para explotar la base de datos, proponemos un método práctico para estimar uno o más de un punto de cambio en secuencias de normales, de binomiales y de multinomiales. El método se basa en el ajuste de modelos y halla los estimadores máximo verosímiles del (de los) punto(s) de cambio. También hemo utilizado un método cluster basado en el ajuste de modelos para a datos politómicos, para agrupar las filas de una tabla de contingencia. Empezamos el estudio realizando un estudio comparativo de 12 formas diferentes de medir la riqueza y diversidad de vocabulario. Las unidades lexicométricas como la longitud de palabra y el uso de palabras frecuentes y libres del contexto nos han sido muy útiles para la estimación del punto de cambio y la atribución de estilo a los capítulos. El uso de letras, a pesar de ser menos útil, sirve para reforzar la evidencia de lo que hallamos con las unidades antes citadas. La longitud de frase y la de capítulo no nos han sido útiles para a determinar una frontera de estilo en el Tirant.Por todos los resultados que hemos ido obteniendo, estamos convencidos que hay un cambio repentino en el estilo entre los capítulos 371 y 382, que difícilmente puede ser atribuible al argumento. También hemos observado que después del punto de cambio conviven capítulos con los dos estilos, lo que probablemente refuerza la teoría de que un segundo autor añadió capítulos sobre un original prácticamente acabado. De todas maneras, no es nuestra misión descubrir que el cambio de estilo no pueda ser debido a otras razones. / This Ph.D. Thesis tackles the problem of the homogeneity of style in Tirant lo Blanc, using the statistical analysis of stylistic features that are measurable but rarely consciously controlled by the author. The goal is to determine whether the style in the book is homogeneous and, if it is not, to find stylistic boundaries. Tirant lo Blanc is the main work in Catalan literature, a chivalry book hailed to be 'the best book of its kind in the world' by Cervantes in Don Quixote, and is considered to be the first modern novel in Europe. There has been an intense and long lasting debate around its authorship originating from conflicting information given in its first edition; while the dedicatory letter states that Joanot Martorell takes sole responsibility for writing the book, the colophon states that the last quarter of the book was written by Martí Joan de Galba, after the death of Martorell. Neither of the two candidate authors left any text comparable to the one under study, and therefore one can not use discriminant analysis to help classify the chapters in the book by author. The majority opinion among medievalists leans towards the single-authorship hypothesis, even though there is a rather strong dissenting minority. In the first part of the thesis we summarize some useful statistical techniques for the quantitative analysis of literary style, we describe the problems that stylometry deals with and we give the state-of-the-art of the authorship attribution problem in Tirant lo Blanc. The data base built by the quantification of style is described as well. The analysis is started by the use of graphical, Statistical Process Control and Correspondence Analysis techniques. In order to obtain maximum likelihood estimates of one or more than one change points in either normal, binomial or multinomial sequences, we propose a practical method based on the fitting of Generalized Linear Models. A cluster method for the rows of a contingency table, based on the fitting of models, is proposed too. We analyze the evolution of the diversity of the vocabulary used in the book through twelve different diversity indices. Following the lead of the extensive stylometry literature, we use word length, and the use of function words to estimate the change point and the attribution of style to the 489 chapters of the book. The use of letters, in spite of being less useful, reinforces the evidences found with the units previously cited. The sentence length and the chapter length weren't useful to determine a style boundary in Tirant The statistical analysis consistently detects a change in style somewhere between chapters 371 and 382, even though a few chapters at the end have a style similar to the ones before that boundary. It is important to remark that even though the statistical analysis supports the existence of two authors, it is not up to us to exclude the possibility that the stylistic boundary found could be explained otherwise.

In industrial processes decreasing variation is very important while achieving the targets. For manufacturers, finding out optimal settings of product and process parameters that are capable of producing desired results under great conditions is crucial. In most cases, the quality response is measured on a continuous scale. However, in some cases, the desired quality response may be qualitative (categorical). There are many effective methods to design robust products/process through industrial experimentation when the response variable is continuous. But methods proposed so far in the literature for robust design with categorical response variables have various limitations. This study offers a simple and effective method for the analysis of categorical response data for robust product or process design. This method handles both location and dispersion effects to explore robust settings in an effective way. The method is illustrated on two cases: A foam molding process design and an iron-casting process design.

Landscape metrics measure the composition and configuration of habitats within landscapes; often the goal is to measure fragmentation. While a variety of existing metrics characterize the connectivity and contiguity of habitat patches, most do not explicitly consider the fragmenting effects of roads in their formulations. This research develops a set of new landscape metrics that explicitly quantify how roads disconnect and break apart habitat patches. This research introduces the following four metrics to consider the fragmenting effects of transportation networks: (1) Number of Connected Patches, a measure of connectivity; (2) Euclidean Nearest Neighbor-Roads, a measure of proximity; (3) Road Density, a measure of dispersion, and (4) Distance to Roads, a measure of division. Each of these formulations explicitly considers the presence of roadways. The metrics are applicable at three spatial scales: patch, class, and landscape. Number of Connected Patches (NCP) provides a new roadway-sensitive measure of patch connectivity by computing the number of patches of identical cover type in a landscape that can be traversed on the shortest straight line distance between them without crossing a road. Euclidean Nearest Neighbor-Roads (ENNR) calculates the distance to the Euclidean nearest neighbor of a patch of the same cover type that is not separated by a roadway. Road Density (RD) leverages the ratio of total roadway network length intersecting a patch, class, or landscape versus respective total unit area. Distance to Roads (DR) provides a new measure of division by taking the shortest Euclidean distance in meters of any patch to the nearest roadway. The performance of the new metrics is evaluated using simulated landscape data with different transportation network structures and habitat patch configurations. This is accomplished by comparing output from the road-based metrics to existing metrics that quantify habitat density, isolation, dispersion, and division. The results of the study demonstrate that the new road-based landscape metrics provide an improved means of quantifying habitat fragmentation caused by transportation networks. This is especially evident as simulated transit network increases for each landscape; response of new metrics to increased road presence is linear and as expected given metric design. These metrics have successfully captured notable patch, class, and landscape level characteristics and their associated responses which are not available with treatment by conventional measures of landscape fragmentation.

This paper describes the `strucplot' framework for the visualization of multi-way contingency tables. Strucplot displays include hierarchical conditional plots such as mosaic, association, and sieve plots, and can be combined into more complex, specialized plots for visualizing conditional independence, GLMs, and the results of independence tests. The framework's modular design allows flexible customization of the plots' graphical appearance, including shading, labeling, spacing, and legend, by means of graphical appearance control (`grapcon') functions. The framework is provided by the R package vcd. (author's abstract) / Series: Research Report Series / Department of Statistics and Mathematics

Previous solutions for the the Law of Categorical Judgment with category boundary variability have either constrained the standard deviations of the category boundaries in some way or have violated the assumptions of the scaling model. In the current work, a fully Bayesian Markov chain Monte Carlo solution for the Law of Categorical Judgment is given that estimates all model parameters (i.e. scale values, category boundaries, and the associated standard deviations). The importance of measuring category boundary standard deviations is discussed in the context of previous research in signal detection theory, which gives evidence of interindividual variability in how respondents perceive category boundaries and even intraindividual variability in how a respondent perceives category boundaries across trials. Although the measurement of category boundary standard deviations appears to be important for describing the way respondents perceive category boundaries on the latent scale, the inclusion of category boundary standard deviations in the scaling model exposes an inconsistency between the model and the rating method. Namely, with category boundary variability, the scaling model suggests that a respondent could experience disordinal category boundaries on a given trial. However, the idea that a respondent actually experiences disordinal category boundaries seems unlikely. The discrepancy between the assumptions of the scaling model and the way responses are made at the individual level indicates that the assumptions of the model will likely not be met. Therefore, the current work examined how well model parameters could be estimated when the assumptions of the model were violated in various ways as a consequence of disordinal category boundary perceptions. A parameter recovery study examined the effect of model violations on estimation accuracy by comparing estimates obtained from three response processes that violated the assumptions of the model with estimates obtained from a novel response process that did not violate the assumptions of the model. Results suggest all parameters in the Law of Categorical Judgment can be estimated reasonably well when these particular model violations occur, albeit to a lesser degree of accuracy than when the assumptions of the model are met.

In drug development clinical trials are designed to investigate whether a new treatment is safe and has the desired effect on the disease in the target patient population. Categorical endpoints, for example different ranking scales or grading of adverse events, are commonly used to measure effects in the trials. Pharmacokinetic/Pharmacodynamic (PK/PD) models are used to describe the plasma concentration of a drug over time and its relationship to the effect studied. The models are utilized both in drug development and in discussions with drug regulating authorities. Methods for incorporation of ordered categorical data in PK/PD models were studied using a non-linear mixed effects modelling approach as implemented in the software NONMEM. The traditionally used proportional odds model was used for analysis of a 6-grade sedation scale in acute stroke patients and for analysis of a T-cell receptor expression in patients with Multiple Sclerosis, where the results also were compared with an analysis of the data on a continuous scale. Modifications of the proportional odds model were developed to enable analysis of a spontaneously reported side-effect and to analyze situations where the scale used is heterogeneous or where the drug affects the different scores in the scale in a non-proportional way. The new models were compared with the proportional odds model and were shown to give better predictive performances in the analyzed situations. The results in this thesis show that categorical data obtained in clinical trials with different design and different categorical endpoints successfully can be incorporated in PK/PD models. The models developed can also be applied to analyses of other ordered categorical scales than those presented.

This thesis deals with the bootstrap method. Three decades after the seminal paper by Bradly Efron, still the horizons of this method need more exploration. The research presented herein has stepped into different fields of statistics where the bootstrap method can be utilized as a fundamental statistical tool in almost any application. The thesis considers various statistical problems, which is explained briefly below. Bootstrap method: A comparison of the parametric and the nonparametric bootstrap of variance is presented. The bootstrap of ranked set sampling is dealt with, as well as the wealth of theories and applications on the RSS bootstrap that exist nowadays. Moreover, the performance of RSS in resampling is explored. Furthermore, the application of the bootstrap method in the inference of contingency table test is studied. Coefficient of variation: This part shows the capacity of the bootstrap for inferring the coefficient of variation, a task which the asymptotic method does not perform very well. Information theory: There are few works on the study of information theory, especially on the inference of entropy. The papers included in this thesis try to achieve the inference of entropy using the bootstrap method.

O objetivo principal da tese é examinar se, na filosofia prática de Immanuel Kant, estariam já contidas distintas variantes da ideia de universalizabilidade, mais especificamente as variantes de Richard Mervyn Hare, Kurt Baier, Marcus George Singer e Jürgen Habermas, com vistas a determinar se a teoria do discurso prático racional de Robert Alexy poderia ser designada como kantiana. O objetivo secundário da tese é examinar se a ideia de universalizabilidade, tal como desenvolvida na lógica formal e na ética de orientação kantiana, pode ser empregada com sucesso na fundamentação filosófica do princípio jurídico da igualdade e da vinculatividade dos precedentes judiciais, bem como apresentar argumentos baseados na universalizabilidade e nos precedentes para a solução de três recursos extraordinários, com repercussão geral reconhecida, que estão pendentes de julgamento pelo Supremo Tribunal Federal brasileiro: Recursos Extraordinários no 611.874, no 639.138 e no 710.293. Os métodos empregados foram o lógico-analítico, o hermenêutico e o comparativo, incluindo também pesquisa bibliográfica, jurisprudencial e legislativa. Os principais resultados obtidos foram estes: (i) do ponto de vista da lógica formal, a universalizabilidade pode ser situada no âmbito das regras de operação do cálculo de predicados de primeira ordem; (ii) com relação às diferentes formulações do imperativo categórico de Kant, a Fórmula IIIa (Reino dos Fins) parece a mais abrangente, ao compreender a forma da ação moral (a lei universal) e a matéria da ação moral (as pessoas como fins em si mesmas); (iii) em seus aspectos essenciais, as variantes da universalizabilidade de Hare, Baier, Singer e Habermas podem ser reconduzidas ao imperativo categórico kantiano; (iv) na filosofia do direito e do estado de Kant, a doutrina da dação de leis dupla explica a diferença entre a dação de leis ética e a dação de leis jurídica com base na diferença da “mola propulsora” (Triebfeder); (v) a existência de uma estreita ligação entre os conceitos de direito (incluindo a possibilidade de coerção externa), de universalizabilidade e de igualdade (na aplicação do direito e no estabelecimento do direito) foi demonstrada; (vi) os dois conceitos fundamentais da teoria do precedente – stare decisis e ratio decidendi – podem ser reconduzidos à ideia de universalizabilidade; (vii) tanto os argumentos baseados na utilização de precedentes, quanto o argumento da universalizabilidade, podem oferecer importantes contribuições para a solução de casos concretos, pendentes de julgamento nos tribunais brasileiros. As conclusões alcançadas a partir dos resultados são que as variantes da ideia de universalizabilidade de Hare, Baier, Singer e Habermas podem, em seus aspectos essenciais, ser reconduzidas à filosofia prática de Kant, demonstrando também a compatibilidade da teoria do discurso prático racional de Alexy com esta filosofia. / The main objective of the thesis is to examine whether in Immanuel Kant’s practical philosophy distinct variants of the idea of universalizability are already contained, in particular Richard Mervyn Hare’s, Kurt Baier’s, Marcus George Singer’s and Jürgen Habermas’ variants, with a view to determine whether Robert Alexy’s theory of rational practical discourse could be construed as Kantian. The secondary objective of the thesis is to examine whether the idea of universalizability, such as developed in formal logic and ethics of Kantian orientation, can be employed successfully in the philosophical foundation of the legal principle of equality and of the binding character of judicial precedent, as well as to present arguments based on universalizability and precedent for the solution of three extraordinary appeals, with recognized general repercussion, which are pending judgment in the Brazilian Federal Supreme Court: Extraordinary Appeals n. 611.874, n. 639.138 and n. 710.293. The methods employed were the logical-analytic, the hermeneutic and the comparative, including also bibliographical, case law and legislative review. The main results obtained were as follows: (i) from the viewpoint of formal logic, universalizability can be located within the domain of operation rules of first order predicate calculus; (ii) in relation to the different formulas of Kant’s categorical imperative, the Formula IIIa (Kingdom of Ends) seems the more inclusive, by comprehending the form of moral action (the universal law) and the matter of moral action (the people as ends in themselves); ( (iii) in their essential aspects, Hare’s, Baier’s, Singer’s and Habermas’ variants of universalizability can be reduced to the Kantian categorical imperative; (iv) in Kant’s philosophy of law and state, the double law-giving doctrine explains the difference between the ethical law-giving and legal law-giving based on the difference between “incentive” (Triebfeder); (v) the existence of a close link between the concepts of law (including the possibility of external coercion), universalizability and equality (in the application of law and in the establishment of law) was demonstrated; (vi) the two fundamental concepts of the theory of precedent – stare decisis and ratio decidendi – can be reduced to the idea of universalizability; (vii) both arguments based on the utilization of precedent and the argument of universalizability can offer an important contribution to the solution of concrete cases, pending judgment in Brazilian courts. The conclusions obtained from the results are that Hare’s, Baier’s, Singer’s and Habermas’ variants of the idea of universalizability can, in their essential aspects, be reduced to Kant’s practical philosophy, also demonstrating the compatibility between Alexy’s theory of rational practical discourse and that philosophy.

O objetivo principal da tese é examinar se, na filosofia prática de Immanuel Kant, estariam já contidas distintas variantes da ideia de universalizabilidade, mais especificamente as variantes de Richard Mervyn Hare, Kurt Baier, Marcus George Singer e Jürgen Habermas, com vistas a determinar se a teoria do discurso prático racional de Robert Alexy poderia ser designada como kantiana. O objetivo secundário da tese é examinar se a ideia de universalizabilidade, tal como desenvolvida na lógica formal e na ética de orientação kantiana, pode ser empregada com sucesso na fundamentação filosófica do princípio jurídico da igualdade e da vinculatividade dos precedentes judiciais, bem como apresentar argumentos baseados na universalizabilidade e nos precedentes para a solução de três recursos extraordinários, com repercussão geral reconhecida, que estão pendentes de julgamento pelo Supremo Tribunal Federal brasileiro: Recursos Extraordinários no 611.874, no 639.138 e no 710.293. Os métodos empregados foram o lógico-analítico, o hermenêutico e o comparativo, incluindo também pesquisa bibliográfica, jurisprudencial e legislativa. Os principais resultados obtidos foram estes: (i) do ponto de vista da lógica formal, a universalizabilidade pode ser situada no âmbito das regras de operação do cálculo de predicados de primeira ordem; (ii) com relação às diferentes formulações do imperativo categórico de Kant, a Fórmula IIIa (Reino dos Fins) parece a mais abrangente, ao compreender a forma da ação moral (a lei universal) e a matéria da ação moral (as pessoas como fins em si mesmas); (iii) em seus aspectos essenciais, as variantes da universalizabilidade de Hare, Baier, Singer e Habermas podem ser reconduzidas ao imperativo categórico kantiano; (iv) na filosofia do direito e do estado de Kant, a doutrina da dação de leis dupla explica a diferença entre a dação de leis ética e a dação de leis jurídica com base na diferença da “mola propulsora” (Triebfeder); (v) a existência de uma estreita ligação entre os conceitos de direito (incluindo a possibilidade de coerção externa), de universalizabilidade e de igualdade (na aplicação do direito e no estabelecimento do direito) foi demonstrada; (vi) os dois conceitos fundamentais da teoria do precedente – stare decisis e ratio decidendi – podem ser reconduzidos à ideia de universalizabilidade; (vii) tanto os argumentos baseados na utilização de precedentes, quanto o argumento da universalizabilidade, podem oferecer importantes contribuições para a solução de casos concretos, pendentes de julgamento nos tribunais brasileiros. As conclusões alcançadas a partir dos resultados são que as variantes da ideia de universalizabilidade de Hare, Baier, Singer e Habermas podem, em seus aspectos essenciais, ser reconduzidas à filosofia prática de Kant, demonstrando também a compatibilidade da teoria do discurso prático racional de Alexy com esta filosofia. / The main objective of the thesis is to examine whether in Immanuel Kant’s practical philosophy distinct variants of the idea of universalizability are already contained, in particular Richard Mervyn Hare’s, Kurt Baier’s, Marcus George Singer’s and Jürgen Habermas’ variants, with a view to determine whether Robert Alexy’s theory of rational practical discourse could be construed as Kantian. The secondary objective of the thesis is to examine whether the idea of universalizability, such as developed in formal logic and ethics of Kantian orientation, can be employed successfully in the philosophical foundation of the legal principle of equality and of the binding character of judicial precedent, as well as to present arguments based on universalizability and precedent for the solution of three extraordinary appeals, with recognized general repercussion, which are pending judgment in the Brazilian Federal Supreme Court: Extraordinary Appeals n. 611.874, n. 639.138 and n. 710.293. The methods employed were the logical-analytic, the hermeneutic and the comparative, including also bibliographical, case law and legislative review. The main results obtained were as follows: (i) from the viewpoint of formal logic, universalizability can be located within the domain of operation rules of first order predicate calculus; (ii) in relation to the different formulas of Kant’s categorical imperative, the Formula IIIa (Kingdom of Ends) seems the more inclusive, by comprehending the form of moral action (the universal law) and the matter of moral action (the people as ends in themselves); ( (iii) in their essential aspects, Hare’s, Baier’s, Singer’s and Habermas’ variants of universalizability can be reduced to the Kantian categorical imperative; (iv) in Kant’s philosophy of law and state, the double law-giving doctrine explains the difference between the ethical law-giving and legal law-giving based on the difference between “incentive” (Triebfeder); (v) the existence of a close link between the concepts of law (including the possibility of external coercion), universalizability and equality (in the application of law and in the establishment of law) was demonstrated; (vi) the two fundamental concepts of the theory of precedent – stare decisis and ratio decidendi – can be reduced to the idea of universalizability; (vii) both arguments based on the utilization of precedent and the argument of universalizability can offer an important contribution to the solution of concrete cases, pending judgment in Brazilian courts. The conclusions obtained from the results are that Hare’s, Baier’s, Singer’s and Habermas’ variants of the idea of universalizability can, in their essential aspects, be reduced to Kant’s practical philosophy, also demonstrating the compatibility between Alexy’s theory of rational practical discourse and that philosophy.

Este trabalho objetiva estudar as propriedades semânticas e categoriais de dois prefixos de negação do português brasileiro, quais sejam in- e des-. Com a evidência de que os prefixos de negação apresentam uma variada gama de categorias lexicais às quais eles podem se adjungir (nomes, adjetivos e verbos), buscamos delinear a frequência com que cada um desses prefixos de negação aparece em relação às suas bases e a semântica por eles atualizada, com o intuito de verificar quais seriam as principais propriedades gramaticais e semânticas capazes de apresentar um papel determinante na eleição e produtividade de determinado prefixo. Através de um estudo que se pretenda exaustivo dos itens lexicais formados por esses prefixos no português, analisamos a plausibilidade da procura de alguma regularidade semântica presente nas bases, para verificar se a distinção entre des- e in- se dá relativamente a determinados elementos de sentido que as palavras formadas por cada prefixo apresentam. Para fins de análise, nos valemos dos vocábulos prefixados com os afixos de negação in- e des- listados no Dicionário de Usos do Português do Brasil, de Francisco S. Borba (2002). Como referencial teórico, elegemos o modelo de Lieber (2004), o qual apresenta o traço [-Loc] como única característica necessária para a descrição da prefixação negativa; esse traço, segundo a autora, pode dar origem a quatro nuances de significado levemente distintas, quais sejam: privação, negação contrária, negação contraditória e reversão. Pelo fato de a Lieber não fazer apontamentos muito relevantes no que diz respeito à seleção categorial, nos valemos dos argumentos de Silva e Mioto (2009) para a análise dos dados do português, os quais advogam pela ideia de que os prefixos selecionam rigidamente as bases com as quais se combinam: in- seleciona apenas bases adjetivais e des- seleciona, além das adjetivais, também bases verbais. Ademais, relativamente a des-, os pesquisadores defendem a existência de dois afixos homófonos: um que seleciona verbos, aplicando o sentido de reversão, e outro que seleciona adjetivos, atualizando o sentido de um tipo de negação. Nossa análise evidencia que parece não existir um suposto traço semântico presente nas bases adjetivais capaz de licenciar a presença de des- ou in-. É provável que, em se tratando de adjetivos especificamente, des- e in- sejam concorrentes – a diferença entre os dois se estabelece mais em termos de produtividade categorial. A postulação de Silva e Mioto (2009) acerca de uma seleção rígida para os prefixos parece não ser condizente com nossos dados. No que tange à análise semântica, defendemos que o traço [-Loc], apesar de ser pertinente quando aplicado a itens lexicais estativos (ou àqueles que não implicam trajetória) prefixados por in- e des-, não é capaz de descrever adequadamente a noção de reversão atualizada por des- quando em presença de bases que denotam processos de mudança. Com isso em vista, defendemos que a solução para melhor descrever esses verbos está no próprio sistema proposto por Lieber, qual seja a evidenciação do traço [+IEPS], que apresenta a noção de trajetória. Esse traço já se faz presente em todos os verbos que implicam processos de mudança e, ao adicionarmos o prefixo negativo, o traço [-Loc] atua sobre [+IEPS], não anulando a presença da trajetória, mas invertendo a direção da mesma. Considerando que [-Loc] se faz presente tanto para a noção de negação quanto para a noção de reversão, não faz sentido a postulação da existência de dois des- homófonos no português para tratar desses dois sentidos. / This thesis aims to study the semantic and categorical properties of two negative prefixes of Brazilian Portuguese, which are in- and des-. With the evidence that the negative prefixes attach to a wide range of lexical categories (nouns, adjectives and verbs), we intend to delineate the frequency with which each of these negative prefixes appears in relation to their bases and the semantics updated by them, in order to see what are the decisive categorical and semantic properties to the election and productivity of the given prefix. Through a study which aims to be exhaustive regarding the lexical items with these prefixes in Portuguese, we analyze the plausibility of looking for some semantic regularity present in the bases, to verify if the distinction between in- and des- occurs with respect to certain elements of meaning present in the words formed by these prefixes. For analysis purposes, we make use of the words with negative affixes in- and des- from Dicionário de Usos do Português do Brasil, by Francisco S. Borba (2002). The theoretical model elected is from Lieber (2004), which exhibits the trace [-Loc] as the only necessary feature to describe the negative affixation; this trace, according to the author, can give rise to four slightly different meanings, which are: privation, contrary negation, contradictory negation and reversion. Since Lieber does not present relevant notes regarding the categorical selection, we make use of Mioto and Silva (2009)‟s arguments for the analysis of Portuguese data. These authors advocate for the idea that prefixes rigidly select the bases to which they combine: in- selects only adjectival bases and des- selects adjectival and also verbal bases. Moreover, for des-, the researchers advocate for the existence of two homophones affixes: one would select verbs, applying the sense of reversion, and the other one would select adjectives, attributing the sense of a kind of negation. Our analysis shows that there seems to be no alleged semantic feature present in adjectival bases able to license the presence of in- or des-. It seems that these prefixes are in competition - the difference between the two is established more in terms of categorical productivity. The postulation of Silva and Mioto (2009) regarding a rigid selection of prefixes does not seem to be consistent with our data. Regarding the semantic analysis, we hold that [-Loc] trace, despite being relevant when applied to stative lexical items (or the ones which do not bear the notion of trajectory) prefixed by in- and des-, is not able to adequately describe the notion of reversion updated by des- when in the presence of bases that denote changing processes. Therefore, we argue that the solution to better describe these verbs are in Lieber‟s theoretical model itself, which is the disclosure of the feature [+IEPS], the one that introduces the notion of trajectory. This feature is already present in all verbs that involve changing processes, and when we add the negative prefix, the feature [-Loc] acts on [+IEPS], not denying the presence of the trajectory, but reversing the direction of it. Whereas [-Loc] is present for both the concept of negation and reversion, it makes no sense to postulate the existence of two homophones des- in Portuguese.