Modelagem linear e identificação do modelo dinâmico de um robô móvel com acionamento diferencial

This work presents a modelling and identification method for a wheeled mobile robot, including the actuator dynamics. Instead of the classic modelling approach, where the robot position coordinates (x,y) are utilized as state variables (resulting in a non linear model), the proposed discrete model is based on the travelled distance increment Delta_l. Thus, the resulting model is linear and time invariant and it can be identified through classical methods such as Recursive Least Mean Squares. This approach has a problem: Delta_l can not be directly measured. In this paper, this problem is solved using an estimate of Delta_l based on a second order polynomial approximation. Experimental data were colected and the proposed method was used to identify the model of a real robot

Utilizando as ciências espaciais e a astronáutica na construção de atividades práticas em ensino de física

In this work we consider the use of new technologies fron the Space Science and Astronautical, in the learning process, incorporating technical and conceptions of physics Spatial what can take on the response of some problems what there are a lot insistent in populate the mind of professors and followers regarding agreement of these conceptions into the level Average. Intending to bring another contribution to Physics teaching practice, especially Classical Mechanics, but introducing many introductory concepts from Modern Physics, since this topic is considered of great interest for teachers and students, for it involves high technology. It s advanced manufacturing demand certain processes that make possible the application of those concepts

A argumentação na petição inicial

This research investigates current sense effects at the use of linguistic resources of the argument in a corpus constituted by juridical pieces (Initial Petitions), that gave opportunity to actions originated from the Civil Special Court of the District of Currais Novos-RN. For this purpose it was established a relation between the Law and the Linguistics, mediated by the focus of the Argumentative Semantics, emphasizing, in a special way, the use of argumentative operators, which inserted in the own language, in its grammar, assume the orientation of the speech and the modalizers use, important mechanisms in the construction of the sense of the text and in the signalling in the way as that that one say is said,. This way, we began the investigation of that gender choosing as study object the section of the facts , that comprehends a part of Initial Petition where is explanted the narration of events that gave margin to the proposal for the Action. In face of the study object and the aim to be reached it was appealed, methodologically, to the notion of Rhetoric since from the classic antiquity to the emergence of the New present Rhetoric in Perelman and Olbrechts-Tyteca (2005) that, at the present time, is inserted in the studies of the Pragmatic connected to the central theses of the Ducrot s thinking (1977, 1980, 1987). Such referential allowed us to a better understanding about the production of the juridical speech on the part of the operators of the Law, as well as, to analyze in way wide the current sense effects from the use of argument linguistic marks the juridical speech. The data showed that such marks are indispensable elements to the construction of the textual web, particularly when in the range of the juridical argumentation, since they direct the speech for certain conclusions. However, we have observed that in the texts produced by the lawyers the use of those linguistic resources not always takes place in an appropriate way. The texts analyzed have also showed that it is possible to unmask, through the linguistic resources, the argumentative strategy employed by the authors for convincing of the magistrate, making evident that language is more than a system of signs, which it makes possible to see beyond the limit of the words and statements. Finally, we have verified that the categories analyzed, when used appropriately, are elements that engender argumentative maneuvers of effectiveness in the juridical text, being fundamental pieces which give argumentative strength the text, making the speech to move forward, not only the juridical, but the speech produced in any domain of the knowledge

Helena de Machado de Assis; Imagens literárias e a retórica da morte da nação inconclusa

Helena is the romance of perishable and discontinuous title character denominator of a dialectic that does not consume and build the narrative by sequential fragmentation combined with episodic frame. The novel is a lightning stroke to the romantic literary project. Therefore, this study aims to find "objective" elements of the novel that would constitute a conception of literary nation proposed by Machado de Assis, as in classical writing, where women are engaged as a metaphor for the nation by a non-cultural heroism, as the example of the Greek myth of Helena, where the feminine represents a mythical image of the nation. The paper's theoretical conception of the history of Walter Benjamin, that is, that is constructed as an allegorical appeal, the conclusions about the disciplinary society of nineteenth century of Michel Foucault, the construction of the nation as a subtle game to remember and forget of Wander Miranda and the rhetoric of death and loss reflected in the speeches of the cultural heritage of José Reginaldo Santos Gonçalves, which allow you to analyze the work permeated by subjectivity and existential conflicts by Machado, who has it arranged in dialectic with the avant-garde literary romanticism and realism. In this relationship with the Greek myth of Helen, explained that characters with the nickname of Helena in Machado's work are not uncommon. As in classical Helena, Machado s Helena uses three rhetorical are the cause of the seizure of the nation. In this game of remembering and forgetting, in the daily plebiscite, Machado draw ideal images that forged our mythical past and commitment to the future. The suffering love of Helena is suffering from failure of the nation which would have led the author to the use of allegorical language, seeking a balance in the chaos generated by the opposition between cruelty and pity widespread view in an area where only left the character's confession guilt for the death. It is a simulacrum of unfinished nation, the space for the game of remembering and forgetting, while the rhetoric of negotiation of our Brazilianness

O discurso autobiográfico nos relatos de viagem de Nísia Floresta

En plein XIXe siècle, Nísia Floresta Brasileira Augusta a écrit sur deux voyages faits en Europe. Quelques années plus tard, cette norte-rio-grandense a livré au public ses récits de voyage : Itinéraire d un voyage en Allemagne (1857) et Trois ans en Italie Suivis d un Voyage en Grèce (1864/1872). Malgré les particularités qui entourent chacun de ces récits, un aspect y est fortement présent : les marques autobiographiques. Notre travail a comme principal objectif enquêter comment se manifeste ce discours autobiographique. A partir de l‟Analyse du Discours, nous avons travaillé quelques positionnements sur certaines oeuvres littéraires, comme par exemple, le fait qu‟elles aient plus d‟un genre. Ce qui se passe dans les récits de voyage de Nísia Floresta est semblable, car au-délà de raconter le passage de Nísia par ces lieux, nous pouvons trouver des caractéristiques qui appartiennent à l‟écriture fragmentaire, autobiographique et épistolaire. Devant les propositions indiquées par Philippe Lejeune, nous avons pu confirmer que ces récits de Nísia font partie de l‟écriture autobiographique. Sous l‟optique de quelques théories, nous avons parcouru des points intéressants qui enveloppent ces récits et, de cette façon, nous avons voyagé avec Nísia Floresta par l‟Allemagne et ultérieurement par l‟Italie et Grèce, en connaissant ainsi, pas seulement un peu plus sur ces lieux, mais beaucoup de confidences sur cette écrivain potiguar, qui a ouvert son coeur au plublic

Eleutheria: a noção de liberdade na ética de Epicuro

Épicure de Samos (341-270 a.C) fut l'un des plus importants penseurs de l'Antiquité. Le philosophe du Jardin, comme il a été connue, aurait écrit au moins 300 volumes. Ayant vécu dans une Grèce sans l'autonomie des temps passés, a vu l'atténuation du sens de liberté (eleutheria) dans le domaine social. En outre, la théorie atomiste que lui précédée et lui a influencée postulais un déterminisme qui avait entraîné la fatalité et l'élimination des eleutheria aussi dans le domaine de la nature (physis). Dans ce contexte, il donne, de la physiología, une forme originale à l'étude de la physis, afin de postuler l'existence du hasard (tychè) agissant dans le monde phisique et de la liberté, dans l‟action humaine. S‟il fait cela, c‟est parce qu‟il croit que être libre est condition du bonheur et celle-ci réside dans le plaisir. Pour cela, Épicure va présenter l'indéterminisme dans le domaine de la physiologie, garantissant l'existence d'un mouvement de déclinaison de l'atome - le parênklisis. Ainsi, dans ce travail, nous allons effectuer une analyse de la façon de se montrer le sens d‟eleutheria développé dans la pensée de ce maître et comment il interagit avec son projet d'éthique. En particulier, nous discutons de comment, de la physiología, Épicure pense un éthos-llibre tourné vers la réalisation du plaisir, de la vie heureuse. Pour cela, nous utilisons la Lettre à Hérodote, la Lettre à Pítocles, la Lettre à Ménécée, 81 Sentences Vaticanes, 40 Maximes Fondamentales et les rapports doxographie

A retórica em Aristóteles: da orientação das paixões ao aprimoramento da eupraxia

This research brings into focus the relationship between the work Rhetoric, from Aristotle, and the conceptions of ethics and practical wisdom of the philosopher from Stageira. Accordingly, it attempts to show that Aristotle's Rhetoric was produced to guide the construction and orientation of oratory passions of the Greek man, setting it as a reference for practices aimed at social ordering of the polis. In other words, the Aristotelian Rhetoric, designed by the author as the study of what is persuasive in every speech, is not composed with the meaning of persuasion at any cost, in another sense it is conceived by Aristotle as a useful knowledge for the improvement eupraxic (the good act in accordance with the fair and true). This research finds that such work has been prepared by Stagirite a time of strong social transformations and upheavals in ancient Greece: The skepticism expanded, with each person wanting to live their own businesses, and especially in Athens, a city that served as intellectual and political reference, there was a lack of collective spirit. In this tumultuous social environment, Aristotle, with a culture of Greeks eager Trusted reviews and socially shareable in the field of verisimilitude, sought with his Rhetoric, contributing to the development of ethics and political science; referrals for legal and organization of inter-social relations in varied environments, including seeking to provide knowledge about human passions and emotional status of active citizens in deliberative meetings

A metafísica de Isaac Newton

The general objective of this dissertation is to analyze the metaphysical aspects of "rational mechanics" of Isaac Newton, clarifying, by scientific and philosophical discourse, their main elements, with emphasis to the presence of one entity infinitely rational behind all the phenomena of nature, and to the Newton's insight as certain empiricist which, however, accepts deductions metaphysics; a philosopher-scientist. The specific objectives are detailed below: a) brief presentation of the development of modern science, since the Pre-Socratics, seeking to understand the historical conjecture that enabled the rise of Newtonian mechanics; b) presentation of the elements of scientific methodology and philosophical, aimed at comprehension of certain "Newtonian methodology", understanding how this specific methodology able to present empirical aspects, mathematics, philosophic and religious in communion; c) to understand, from the Newtonian concepts, both concerning man's role in the world as the "notional notions" of mass, space, time and movement, necessary for analysis and understanding of certain metaphysical aspects in the Newtonian physics; d) to present the Newtonian concepts related to the ether, to understand why it necessarily assumes metaphysics characteristics and mediation between the bodies; e) to present and understand the factors that lead the empiricist Newton to assume the religion in his mechanics, as well as, the existence and functions of God in nature, to object to the higher content of his metaphysics; f) to highlight the metaphysical elements of his classical mechanics, that confirm the presence of concepts like God Creator and Preserver of the natural laws; g) at last, to analyze the importance of Newton to the modern metaphysics and the legacy to philosophy of science at sec. XVII to science contemporary

Nietzsche e a modernidade: da crítica à metafísica à crítica à democracia

This dissertation presents an interpretation concerning the critical considerations of the German philosopher Friedrich Nietzsche on Modernity, especially Nietzsche s criticism of Modernity, of Christian mores and democracy produced by him in Beyond Good and Evil. Nietzsche attentively analyses details of Modernity, produces a diagnosis of modern man and discovers the sign of decay. We consider that Nietzsche s criticism of modernity is directly linked to the criticism of classic metaphysics. We emphasize questions like: what in us aspires to truth? Christian mores: why and what for? What characterizes modernity? Could it be the appeal to the democratic taste? Is it possible to reinvent Modernity? We stress the relation between the notion of truth, democracy and Christian mores, showing that these mores were also inherited from the Socratic culture. We also intend to clarify Nietzsche s proposal of a new way of doing philosophy, that would be able to surpass the decay which rules in European modern culture. The end of this research points out to the ―philosophers of the future‖ who are able, according to Nietzsche, to claim life beyond the metaphysics opposition, beyond the good and the evil

Fundamentos da filosofia moral de Peter Singer

This research aims to reconstruct and explain the argument proposed by Peter Singer to justify the principle of equal consideration of interests (PECI). The PECI is the basic normative principle according to people should consider the interests of all sentient beings affected when somebody taking a moral decision. It is the join that Singer proposes between universalizability and the principle of equal consideration of interests that constitutes a compelling reason to justify it. The universalizability requires to disregard the numerical differences, putting yourself in other people s shoes, and to consider preferences, interests, desires and ideals of those affected. Singer joins universalizability to normative principle and molds the form and content of his theory. The first chapter introduces the discussion will be developed in this essay. The second chapter deals the historical and philosophical viewpoint from which Singer starts his studies. The third chapter is about the Singer s critiques of naturalism, intuitionism, relativism, simple subjectivism and emotivism. The fourth chapter exposes the design of universal prescriptivism proposed by R. M. Hare. The universal prescriptivism indicates, in the Singer s viewpoint, a consistent way to create the join between the universalizability and PECI. It highlights also the criticism designed by J. L. Mackie and Singer himself to universal prescriptivism. The second part of this chapter shows briefly some of the main points of the classical conception of utilitarianism and its possible relationship with the theory of Singer. The fifth chapter introduces the Singer s thesis about the origin of ethics and the universalizability as a feature necessary to the point of view of ethic, and the way which this argument is developed to form the PECI. The sixth chapter exposes the main distinctions that characterize the PECI. Finally the seventh chapter provides a discussion about the reasons highlighted by Singer for one who wants orient his life according to the standpoint of ethics. This structure allows explaining the main ideas of the author concerning the theoretical foundations of his moral philosophy

Filtros acústicos em cristais fonônicos

In this work, we have studied the acoustic phonon wave propagation within the periodic and quasiperiodic superlattices of Fibonacci type. These structures are formed by phononic crystals, whose periodicity allows the raise of regions known as stop bands, which prevent the phonon propagation throughout the structure for specific frequency values. This phenomenon allows the construction of acoustic filters with great technological potential. Our theoretical model were based on the method of the transfer matrix, thery acoustics phonons which describes the propagation of the transverse and longitudinal modes within a unit cell, linking them with the precedent cell in the multilayer structure. The transfer matrix is built taking into account the elastic and electromagnetic boundary conditions in the superllatice interfaces, and it is related to the coupled differential equation solutions (elastic and electromagnetic) that describe each model under consideration. We investigated the piezoelectric properties of GaN and AlN the nitride semiconductors, whose properties are important to applications in the semiconductor device industry. The calculations that characterize the piezoelectric system, depend strongly on the cubic (zinc-bend) and hexagonal (wurtzite) crystal symmetries, that are described the elastic and piezoelectric tensors. The investigation of the liquid Hg (mercury), Ga (gallium) and Ar (argon) systems in static conditions also using the classical theory of elasticity. Together with the Euler s equation of fluid mechanics they one solved to the solid/liquid and the liquid/liquid interfaces to obtain and discuss several interesting physical results. In particular, the acoustical filters obtained from these structures are again presented and their features discussed

Um estudo na teoria do movimento brownianno com viscosidade variável

In this work we investigate the stochastic behavior of a large class of systems with variable damping which are described by a time-dependent Lagrangian. Our stochastic approach is based on the Langevin treatment describing the motion of a classical Brownian particle of mass m. Two situations of physical interest are considered. In the first one, we discuss in detail an application of the standard Langevin treatment (white noise) for the variable damping system. In the second one, a more general viewpoint is adopted by assuming a given expression to the so-called collored noise. For both cases, the basic diffententiaql equations are analytically solved and al the quantities physically relevant are explicitly determined. The results depend on an arbitrary q parameter measuring how the behavior of the system departs from the standard brownian particle with constant viscosity. Several types of sthocastic behavior (superdiffusive and subdiffusive) are obteinded when the free pamameter varies continuosly. However, all the results of the conventional Langevin approach with constant damping are recovered in the limit q = 1

Estudos de modelos Estocásticos: processo de contato, séries aleatórias e processos difusivos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Montagem e construção de um magnetômetro a efeito Kerr magneto-óptico

n this master s dissertation a Kerr Magneto Optic s magnetometer effect was set up to do characterization of samples type films fine and ultra thin, these samples will be grown after the implementation of the sputtering technique at the magnetism laboratory of of this department. In this work a cooled electromagnet was also built the water and that it reaches close values to 10kOe with a gap of 22 mm including an area of uniform field of 25mm of diameter. The first chapter treats of the construction of this electromagnet from its dimensioning to the operation tests that involve measures of reached maximum field and temperature of the reels when operated during one hour. The second chapter is dedicated to the revision of the magnetism and the magnetization processes as well as it presents a theoretical base regarding the magnetic energies found in films and magnetic multilayer. In the sequence, the third chapter, is especially dedicated the description of the effects magneto opticians the effect kerr in the longitudinal, traverse and polar configurations, using for so much only the classic approach of the electromagnetism and the coefficients of Fresnel. Distinguished the two areas of observation of the effect regarding thickness of the film. The constructive aspects of the experimental apparatus as well as the details of its operation are explained at the room surrender, also presenting the preliminary results of the measures made in one serializes of permalloy films and concluding with the results of the characterization of the first films of iron and permalloy grown here at the theoretical and experimental physics department at UFRN

Elétrons fortemente correlacionados na vizinhança de uma transição de fase quântica

The aim of this work is to derive theWard Identity for the low energy effective theory of a fermionic system in the presence of a hyperbolic Fermi surface coupled with a U(1) gauge field in 2+1 dimensions. These identities are important because they establish requirements for the theory to be gauge invariant. We will see that the identity associated Ward Identity (WI) of the model is not preserved at 1-loop order. This feature signalizes the presence of a quantum anomaly. In other words, a classical symmetry is broken dynamically by quantum fluctuations. Furthermore, we are considering that the system is close to a Quantum Phase Transitions and in vicinity of a Quantum Critical Point the fermionic excitations near the Fermi surface, decay through a Landau damping mechanism. All this ingredients need to be take explicitly to account and this leads us to calculate the vertex corrections as well as self energies effects, which in this way lead to one particle propagators which have a non-trivial frequency dependence