The design of controllers subject to the nonlinear H-infinity criterion is explored. The plants to be controlled are the attitude motion of spacecraft, subject to some disturbance torque. Two cases are considered: the regulation about an inertially-fixed direction, and an Earth-pointing spacecraft in a circular orbit, subject to the gravity-gradient torque. The spacecraft attitude is described using the modified Rodrigues parameters. A series of controllers are designed using the nonlinear H-infinity control criterion, and are subsequently generated using a Taylor series expansion to approximate solutions of the relevant Hamilton-Jacobi equations. The controllers are compared, using both input-output and initial condition simulations. A proof is used to demonstrate that the linearized controller solves the H-infinity control problem for the inertial pointing problem when describing the plant using the modified Rodrigues parameters.

The thesis analyses and validates Beamforming methods using Convex Optimization.  CVX which is a Matlab supported tool for convex optimization has been used to develop this concept. An algorithm is designed by which an appropriate system has been identified by varying parameters such as number of antennas, passband width, and stopbands widths of a beamformer. We have observed the beamformer by minimizing the error for Least-square and Infinity norms. A graph obtained by the optimum values between least-square and infinity norms shows us a trade-off between these two norms. We have observed convex optimization for double passband of a beamformer which has proven the flexibility of convex optimization. On extension for this, we designed a filter in which stopband is arbitrary. A constraint is used by which the stopband would be varying depending upon the upper boundary (limiting) line which varies w.r.t y-axis (dB). The beamformer has been observed for feasibility by varying parameters such as number of antennas, arbitrary upper boundaries, stopbands and passband. This proves that there is flexibility for designing a beamformer as desired.

This study aims to accomplish two tasks: First, it is argued that an &lsquo / ethical transcendental philosophy&rsquo / is possible with Levinas. Second, the concepts that bear this possibility to a philosophically acceptable level of cogency can be clarified. Philosopher&rsquo / s position in history of philosophy suggests a kind of &lsquo / externality&rsquo / in the sense that he is not within the realm of very tradition. Levinas&rsquo / predisposition is rather to employ what he calls &lsquo / peri-phrases&rsquo / that hinder the philosopher to settle in the existing structure of concepts (read as Greek language). This position can also be read as a resistance to dominating forms of knowledge. Levinas takes this attitude as an important point of resistance against Western metaphysics that puts the ontology at the center. Against this tradition, he celebrates both the &lsquo / encounter with the Other&rsquo / as a pilot point in ethics, one that all rest of which follows from, and the priority of &lsquo / the Good&rsquo / . In such a way, &lsquo / I&rsquo / has been put into question in its gay independence without any reference to self contained totality, of the kind which is &lsquo / self intelligible&rsquo / . This attachment that is infinition, of infinity helps us experience not a totality, but &lsquo / otherwise than being&rsquo / . This attitute might resonate with the Kantian attempt displacing knowledge in order to make room for morality. However, a closer reading would notice that there is another agenda here, one that attempts to go to a status of pre-rationality, beyond rationality, so to speak an agenda that radicalizes the Kantian attempt. Derrida, a philosopher who showed that this attempt was just impossible, impossible in the sense that it was contaminated at the very beginning, skillfully benefits from the very inspiration Levinas has provided with. All these attempts and conceptual suggestions have been examined and analyzed, and the Levinasian inspiration has been tried to be elucidated.

Cette étude a pour objectif de démontrer l'importance capitale de Lucrèce dans l'introduction de l'infini à Rome et au sein de l'histoire de la philosophie : bien qu'il se fonde sur les écrits de son maître grec, Épicure, le poète propose une réponse nouvelle, originale, moderne et féconde à la dialectique du Tout et de l'infini en réconciliant ces deux notions au moyen de son poème en langue latine. Sous son stylet, l'infini devient plus réel, plus tangible et évident, plus vaste et intense, plus enthousiasmant et grandiose. La poésie n'est pas seulement un agrément. Elle contribue à la maîtrise de l'infini épicurien et à la valorisation de cette notion. La démarche adoptée pour cette démonstration, bien que littéraire à la base, est transdisciplinaire : l'étude tente d'offrir une vision synthétique de l'infini de Lucrèce, poète, philosophe et scientifique. / This study aims to demonstrate Lucretius'major role in the introduction of infinity in Rome and within the history of philosophy. Although he bases his argument on the writings of his Greek teacher, Epicurus, the poet offers a new, original, modern and fertile answer to the dialectic of the Whole and infinity when reconciling these two notions by means of his poem in Latin language. Under his stylus, infinity becomes more real, more tangible and obvious, vaster and more intense, more exciting and magnificent. The poetry is not only a charm. It contributes to the good command of the Epicurean infinity and to the promotion of this notion. The approach I adopted for this demonstration, although literary at the root, is interdisciplinary : the study tries to offer a synthetic view of the infinity of Lucretius, a poet, a philosopher and a scientist.

Ce titre de plénitude ontologique du vide signifie que le vide n’est pas un néant, un rien ou une absence définitive mais, au contraire, l’affirmation en son autosuffisance de la présence à l’état pur. Le vide est plein de la présence pure, mieux il s’identifie à elle. De l’atomisme antique à la Révolution scientifique en passant par la Renaissance, de Démocrite à Newton via Bruno, d’Aristote à Descartes en tant que ses plus éminentes adversaires, le vide n’a cessé de hanter tant le champ de la métaphysique que celui de la science, celui de l’expérience comme celui de l’imaginaire. Après avoir tenté de l’expulser de la physique au moyen de la notion d’éther, la cosmologie contemporaine redécouvre le rôle essentiel du vide dans le devenir et peut-être l’origine de l’univers. Aujourd’hui, c’est au tour de la métaphysique de soupeser à nouveaux frais le poids du vide dans le cadre de la problématique qui lui est propre. Si le vide, en tant que lieu par excellence de l’exposition de la présence, projette l’ontologie fondamentale vers sa véritable dimension, la question de l’être telle que l’entendait Heidegger prend alors toute son amplitude, non plus mondaine mais cosmologique. C’est alors tous les concepts fondamentaux heideggériens (monde, temporalité, Dasein) qui doivent être réévalué à l’aune de cette nouvelle image de la pensée imposée par la nécessité du vide. L’heideggerianisme indique-t-il ainsi une avancée ou marque-t-il une régression par rapport aux pensées cosmologiques de la métaphysique classique ? Car c’est bien une toute autre image de la pensée que celle des déconstructions qu’il s’agit de fonder, celle où les concepts de présence, de substance, de fondement et même d’Absolu recouvrent toute leur actualité. / The title of ontological fullness of the void means that the void is not a nothingness, a mere nothing or a definitive absence but, on the contrary, an assertion in its self-sufficiency of the presence in the pure state. The void is full of the pure presence, better it is identified with it. From ancient atomism to the scientific Revolution including the Renaissance, from Democritus to Newton via Bruno, from Aristotle to Descartes as their most eminent opponents, the void did not stop haunting both the field of the metaphysics and that of the science, that of the experiment as that of the imagination. Having tried to expel it from the physics by means of the notion of ether, the contemporary cosmology rediscovers the essential role of the void in the future and maybe the origin of the universe. Today, it is in the turn of the metaphysics to feel the weight at new expenses of the weight of the void within the framework of the problem of its own. If the void, as pre-eminently place of the exhibition of the presence, throws the fundamental ontology towards its real dimension, the question of the being such as heard it Heidegger takes then all its amplitude, either worldly but cosmological. It is then all the fundamental heideggerian concepts (world, temporality, Dasein) that must be revalued in the alder of this new image of the thought been imperative by the necessity of the void. Does the heideggerianism so indicate an advance or does it mark a regression with regard to the cosmological thoughts of the classic metaphysics? Because it is well very another image of the thought which that of the deconstructions which it is a question of basing, that where the concepts of presence, substance, foundation and even Absolute recover all their present situation.

x, 68 p. : ill. (some col.) / Motivated by the Adams spectral sequence for computing stable homotopy groups, Priddy defined a class of algebras called Koszul algebras with nice homological properties. Many important algebras arising naturally in mathematics are Koszul, and the Koszul property is often tied to important structure in the settings which produced the algebras. However, the strong defining conditions for a Koszul algebra imply that such algebras must be quadratic. A very natural generalization of Koszul algebras called K 2 algebras was recently introduced by Cassidy and Shelton. Unlike other generalizations of the Koszul property, the class of K 2 algebras is closed under many standard operations in ring theory. The class of K 2 algebras includes Artin-Schelter regular algebras of global dimension 4 on three linear generators as well as graded complete intersections. Our work comprises two distinct projects. Each project was motivated by an aspect of the theory of Koszul algebras which we regard as sufficiently powerful or fundamental to warrant an interpretation for K 2 algebras. A very useful theorem due to Backelin and Fröberg states that if A is a Koszul algebra and I is a quadratic ideal of A which is Koszul as a left A -module, then the factor algebra A/I is a Koszul algebra. We prove that if A is Koszul algebra and A I is a K 2 module, then A/I is a K 2 algebra provided A/I acts trivially on Ext A ( A/I,k ). As an application of our theorem, we show that the class of sequentially Cohen-Macaulay Stanley-Reisner rings are K 2 algebras and we give examples that suggest the class of K 2 Stanley-Reisner rings is actually much larger. Another important recent development in ring theory is the use of A ∞ -algebras. One can characterize Koszul algebras as those graded algebras whose Yoneda algebra admits only trivial A ∞ -structure. We show that, in contrast to the situation for Koszul algebras, vanishing of higher A ∞ -structure on the Yoneda algebra of a K 2 algebra need not be determined in any obvious way by the degrees of defining relations. We also demonstrate that obvious patterns of vanishing among higher multiplications cannot detect the K 2 property. This dissertation includes previously unpublished co-authored material. / Committee in charge: Dr. Brad Shelton, Chair; Dr. Victor Ostrik, Member; Dr. Nicholas Proudfoot, Member; Dr. Arkady Vaintrob, Member; Dr. David Boush, Outside Member

abstract: This thesis addresses the design and control of three phase inverters. Such inverters are used to produce three-phase sinusoidal voltages and currents from a DC source. They are critical for injecting power from renewable energy sources into the grid. This is especially true since many of these sources of energy are DC sources (e.g. solar photovoltaic) or need to be stored in DC batteries because they are intermittent (e.g. wind and solar). Two classes of inverters are examined in this thesis. A control-centric design procedure is presented for each class. The first class of inverters is simple in that they consist of three decoupled subsystems. Such inverters are characterized by no mutual inductance between the three phases. As such, no multivariable coupling is present and decentralized single-input single-output (SISO) control theory suffices to generate acceptable control designs. For this class of inverters several families of controllers are addressed in order to examine command following as well as input disturbance and noise attenuation specifications. The goal here is to illuminate fundamental tradeoffs. Such tradeoffs include an improvement in the in-band command following and output disturbance attenuation versus a deterioration in out-of-band noise attenuation. A fundamental deficiency associated with such inverters is their large size. This can be remedied by designing a smaller core. This naturally leads to the second class of inverters considered in this work. These inverters are characterized by significant mutual inductances and multivariable coupling. As such, SISO control theory is generally not adequate and multiple-input multiple-output (MIMO) theory becomes essential for controlling these inverters. / Dissertation/Thesis / Masters Thesis Electrical Engineering 2015

Made available in DSpace on 2015-05-14T12:11:55Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1239468 bytes, checksum: 8084abcbccc739b16255bcd4c0ca478c (MD5) Previous issue date: 2013-09-13 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This study of "The bruniane cosmology as an assumption of moral reform" aims to analyze the relationship between the cosmological argument and the proposition of a moral reform on Giordano Bruno's thinking. This analysis was made from four works: Cena, De la causa, L infinito e Spaccio. The first three are fundamental to a cosmologic approach and the later address a reform of values. The structure of the cosmos held by Bruno has the following structure: the universe is infinite and populated by countless worlds. Such a statement in the sixteenth century was distant of the egocentric cosmology, in which the universe was considered to be finite and bounded by the sphere of the fixed stars and the Earth was motionless at the center of this structure. In works that deal with cosmology, Bruno elaborates a criticism of this model, having as his main interlocutor Aristotle. Copernicus, then, becomes the reference mark in which Bruno finds the support to elaborate his cosmology. However, the theme about the new structure of the cosmos is not limited to the sphere of philosophy of nature, it's also permeated by a theological dimension. Bruno accuses supporters of the finite universe of defending the existence of a fundamental infinite cause, God, which has as an effect the finite, the universe. The philosopher from Nola assumes that nature is a simulacrum of the divine and thus must also be infinite. He began his publications addressing the cosmological theme, but that wasn't an issue that was in crisis at the time, despite the astronomical evidences such as the emergence of a star called Nova in 1572 and the appearance of a comet in 1577. These events were not considered by astronomers of the period as evidence that contradicted the Aristotelian-Ptolemaic cosmological thesis. They provided a reading of the eschatological end of time, both by religious and intellectuals, an interpretation that was ignored by Bruno, who conceived the astronomical phenomena the end of an era, not of the physical world. The religious crisis that pervaded this period was mainly focused on the division of Christians into catholics and reformers. This crisis was more apparent than the cosmological one. But Bruno started its publications addressing the issue of the structure of the cosmos. We believe that his choice of dealing with cosmological themes rather than religion is based on the idea that it was not possible to discuss the religious crisis without first analyzing the cosmic structure on which society was based. In the work Spaccio Bruno hints towards a heavenly moral reform. The divine world is described as being crossed by the changes, the vicissitudes. This model could only be possible in a world considered as homogeneous, in which there is no distinction between its elements, between the human world and the divine. / Este estudo sobre A cosmologia bruniana como pressuposto de uma reforma moral , tem como objetivo analisar uma possível relação entre a discussão cosmológica e o tema da moral no pensamento de Giordano Bruno. Essa analise foi realizada a partir de quatro obras: Cena, De la causa, L infinito e Spaccio. As três primeiras são fundamentais à abordagem cosmológica e a última trata de uma reforma dos valores. A estrutura do cosmo defendida por Bruno tem a seguinte estrutura: o universo é infinito e povoado de inumeráveis mundos. Essa posição no século XVI destoava da cosmologia geocêntrica, na qual o universo era considerado como sendo finito e delimitado pela esfera das estrelas fixas. E a Terra estava imóvel no centro dessa estrutura. Nas obras que tratam da cosmologia, Bruno elabora uma crítica a esse modelo, tendo como principal interlocutor Aristóteles. Copérnico, em seguida, é o referencial no qual Bruno se apoia para elaborar a sua cosmologia. Mas o tema sobre a nova estrutura do cosmo não está circunscrito apenas à esfera da filosofia da natureza. Ele é também permeado por uma dimensão teológica. Bruno acusa os partidários do universo finito de defenderem a existência de uma causa primeira infinita, Deus, que tem como efeito o finito, o universo. O filósofo nolano parte do pressuposto de que a natureza é um simulacro do divino e, dessa forma, deve ser também infinita. Ele iniciou as suas publicações abordando o tema cosmológico, mas esse não era uma temática que estava em crise, apesar dos indícios astronômicos como o surgimento de uma estrela denominada Nova em 1572 e o aparecimento de um cometa em 1577. Esses eventos não foram considerados pelos astrônomos da época como indícios que refutassem a tese cosmológica aristotélico-ptolomaica. Elas propiciaram uma leitura escatológica do fim dos tempos, tanto pelos religiosos como pelos intelectuais. Leitura ignorada por Bruno, que concebia nos fenômenos astronômicos o fim de uma era, não do mundo físico. A crise religiosa que permeava esse período tinha como principal foco a divisão dos cristãos em católicos e reformadores. Essa crise era mais evidente que a cosmológica. Mas Bruno iniciou as suas publicações abordando o tema da estrutura do cosmo. Consideramos que a sua opção pela temática cosmológica em detrimento da religiosa se assenta na ideia de que não era possível discutir a crise religiosa sem antes analisar a estrutura cósmica sobre a qual a sociedade se assentava. Na obra Spaccio Bruno trata de uma reforma moral celeste. O mundo divino é descrito como sendo atravessado pelas mudanças, pelas vicissitudes. Esse modelo só seria possível num mundo considerado como homogêneo, no qual não há distinção entre os seus elementos, entre mundo humano e divino.

abstract: The problem of systematically designing a control system continues to remain a subject of intense research. In this thesis, a very powerful control system design environment for Linear Time-Invariant (LTI) Multiple-Input Multiple-Output (MIMO) plants is presented. The environment has been designed to address a broad set of closed loop metrics and constraints; e.g. weighted H-infinity closed loop performance subject to closed loop frequency and/or time domain constraints (e.g. peak frequency response, peak overshoot, peak controls, etc.). The general problem considered - a generalized weighted mixed-sensitivity problem subject to constraints - permits designers to directly address and tradeoff multivariable properties at distinct loop breaking points; e.g. at plant outputs and at plant inputs. As such, the environment is particularly powerful for (poorly conditioned) multivariable plants. The Youla parameterization is used to parameterize the set of all stabilizing LTI proper controllers. This is used to convexify the general problem being addressed. Several bases are used to turn the resulting infinite-dimensional problem into a finite-dimensional problem for which there exist many efficient convex optimization algorithms. A simple cutting plane algorithm is used within the environment. Academic and physical examples are presented to illustrate the utility of the environment. / Dissertation/Thesis / M.S. Electrical Engineering 2013

Submitted by Irene Nascimento (irene.kessia@ufpe.br) on 2016-06-27T17:33:44Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) DISSERTACAO_CJEland_DEFINITIVA.pdf: 1117645 bytes, checksum: 72bd32d2e20b55b08b4f94191834359b (MD5) / Made available in DSpace on 2016-06-27T17:33:44Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) DISSERTACAO_CJEland_DEFINITIVA.pdf: 1117645 bytes, checksum: 72bd32d2e20b55b08b4f94191834359b (MD5) Previous issue date: 2016-02-02 / CAPES / A presente dissertação tem como objetivo examinar a relação entre o conceito de fraternidade nos primeiros escritos de Emmanuel Levinas, especialmente em Totalidade e Infinito, e suas obras posteriores sobre Direitos Humanos a fim de investigar uma possível fundamentação não liberal para os Direitos Humanos na contemporaneidade. Para tanto, será necessário explicitar como a obra de Levinas sobre a relação ética para com o Outro que fundamenta sua ideia de Direitos Humanos se ancora na relação política para com o terceiro. O conceito de fraternidade, como a não-indiferença universal para com o Outro, implica o conteúdo dessa relação ética que vai além da ética e permeia as categorias tradicionalmente políticas do pensamento filosófico. Assim, através da leitura relacional entre o conceito de Direitos Humanos e o conceito de fraternidade, que toma forma política na figura do terceiro, torna-se claro que a perspectiva de Levinas sobre os direitos como direitos dos outros se opõe a uma leitura liberal do seu trabalho, podendo, portanto, apontar para uma leitura não liberal dos direitos humanos na atualidade. / This dissertation seeks to examine the relationship between Emmanuel Levinas’s early work on fraternity, especially Totality and Infinity, and his later work on Human Rights in order to investigate the possibility of a non-liberal foundation for Human Rights in the contemporary world. In order to achieve this, it is necessary to develop the way in which Levinas’s work on the ethical relation to the Other serves as the foundation of his concept of Human Rights and anchors the political relation to the third party. The concept of fraternity, as a universal non-indifference to the Other, implies the content of the ethical relation which goes beyond ethics and reaches into traditionally political categories of philosophical thought. As such, by reading Levinas’s concept of Human Rights in relation to this early concept of fraternity, which takes its political form through the third party, his account of rights as the rights of the other stands in clear opposition to a liberal understanding of his work and describes a non-liberal account of human rights in the contemporary world.