The wireless market is developing very fast today with a steadily increasing number of users all around the world. An increasing number of users and the constant need for higher and higher data rates have led to an increasing number of emerging wireless communication standards. As a result there is a huge demand for flexible and low-cost radio architectures for portable applications. Moving towards multistandard radio, a high level of integration becomes a necessity and can only be accomplished by new improved radio architectures and full utilization of technology scaling. Modern nanometer CMOS technologies have the required performance for making high-performance RF circuits together with advanced digital signal processing. This is necessary for the development of low-cost highly integrated multistandard radios. The ultimate solution for the future is a software-defined radio, where a single hardware is used that can be reconfigured by software to handle any standard. Direct analog-to-digital conversion could be used for that purpose, but is not yet feasible due to the extremely tough requirements that put on the analog-to-digital converter (ADC). Meanwhile, the goal is to create radios that are as flexible as possible with today’s technology. The key to success is to have an RF front-end architecture that is flexible enough without putting too tough requirements on the ADC. One of the key components in such a radio front-end is a multiband multistandard low-noise amplifier (LNA). The LNA must be capable of handling several carrier frequencies within a large bandwidth. Therefore it is not possible to optimize the circuit performance for just one frequency band as can be done for a single application LNA. Two different circuit topologies that are suitable for multiband multistandard LNAs have been investigated, implemented, and measured. Those two LNA topologies are: (i) wideband LNAs that cover all the frequency bands of interest (ii) tunable narrowband LNAs that are tunable over a wide range of frequency bands. Before analog-to-digital conversion the RF signal has to be downconverted to a frequency manageable by the analog-to-digital converter. Recently the concept of direct sampling of the RF signal and discrete-time signal processing before analog-to-digital conversion has drawn a lot of attention. Today’s CMOS technologies demonstrate very high speeds, making the RF-sampling technique appealing in a context of multistandard operation at GHz frequencies. In this thesis the concept of RF sampling and decimation is used to implement a flexible RF front-end, where the RF signal is sampled and downconverted to baseband frequency. A discrete-time switched-capacitor filter is used for filtering and decimation in order to decrease the sample rate from a value close to the carrier frequency to a value suitable for analog-to-digital conversion. To demonstrate the feasibility of this approach an RF-sampling front-end primarily intended for WLAN has been implemented in a 0.13 μm CMOS process.

No description available.

DNA double-strand breaks (DSBs) are lethal in eukaryotic cells if left unrepaired. In Saccharomyces cerevisiae the Mre11/Rad50/Xrs2 (MRX) complex is required for repair of DSBs through homologous recombination and nonhomologous end joining. Although Mre11 complexes exhibit 3'[rightwards arrow]5' exonuclease activity and endonuclease activity on DNA hairpin and single-stranded DNA overhang substrates in vitro, the role of the MRX complex in homologous recombination in vivo is not well understood. It has been shown to be specifically required for the processing of protein-conjugated DNA ends at DSBs during meiosis and hairpin-capped DSBs in mitotic cells and has been suggested that the Mre11 nuclease functions to remove damaged DNA ends. Recently, the Sae2 protein has been demonstrated to be involved in hairpin-capped DSBs and DNA end processing along with MRX in vivo. However, the Sae2 protein has no known homologs outside of fungi and no obvious motifs to suggest the function(s) of the Sae2 protein. We have purified recombinant Sae2 and MRX and report that the Sae2 protein itself is a single-stranded DNA endonuclease. The Sae2 protein stimulates the 3[rightwards arrow]5' exonuclease activity of the MRX complex. Also, the MRX complex can stimulate Sae2 nuclease activity to cleave ssDNA adjacent to DNA hairpin structures. The Sae2 protein also binds independently to double-stranded DNA and forms higher order protein-DNA complexes with MRX. These results provide biochemical evidence for functional cooperatively between MRX and Sae2 on DSBs and hairpin-capped DNA ends. / text

This thesis addresses how leaders find themselves doing something even when they don't know what to do. It is based on my own practice as an experienced team leader and it deals with questions of action, time, identity and leadership. A classic understanding of action usually reflects an expectation of a rational means-ends relationship where actions are designed and applied by individuals to reach well-defined goals within a certain context and within a certain time. In contrast, in this thesis, I describe acting as a much more complex process, as something becoming, as a patterning of activities involving multiple actors in a continuous and complex interweaving of relationships. I describe my experience of leading a team of consultants in international development projects where I inquire into how we often find ourselves acting into uncertainty even when we are not at all sure what to do. Adopting the theory of complex responsive processes of relating, which combines insights from the complexity sciences, social psychology and process sociology, I have come to see acting in our projects as complex, unpredictable, emerging themes and patterns of dialogues between colleagues, clients and other actors, rather than as an activity undertaken by an individual such as a team leader. I do not have an outside position to acting in a project as I am fully involved in the process while this paradoxically influences me at the same time. I argue that acting is related to identity, which can be understood as a sense of self, a person's moral self-interpretation which has a narrative structure and which is continuously being formed by (and is forming) one's acting. I argue that my experience of our practice may be explained by the pragmatists' understanding of acting based on actual lived experience where the means paradoxically become our 'ends-in-view' and vice versa, meaning that we do not just try to maintain a theoretical, future goal but move forwards towards what is practically possible, what we find useful and what makes sense in the present. Acting happens in a living present, meaning that we understand the present through our interpretation of the past as well as our expectation of the future, and we construct this living present as something that works for us when we pursue our collective aims and interests. In the process of acting, there is an arrow on time, meaning that what has been said cannot be unsaid, wherefore it is important to reflect on the perspective of 'ends-in-view' and to understand how acting into a situation may reveal new opportunities. The thesis contributes to knowledge within my profession as an original invitation to think differently about two aspects: first, seeing acting in a project with a much more processual, temporal and encompassing understanding where action is not located in an individual; second, understanding how acting is influenced by one's identity, a sense of self, which is paradoxically being formed by the acting at the same time. Further, the thesis identifies sociality, being different things at the same time (Mead, 1932/2002), as a new aspect in the theory of complex responsive processes of relating (Stacey, Griffin, & Shaw, 2000), recognising its significance in the process of understanding of how novelty occurs. The thesis contributes to my practice in terms of an increased reflexivity and acceptance that a team leader cannot determine outcomes in advance; that leadership is a complex process involving many actors; and that observing ends-in-view may create new and surprising ways forward. I find that these insights can lead to an increased acceptance of how we can act under conditions of uncertainty.

abstract: Building computational models of human problem solving has been a longstanding goal in Artificial Intelligence research. The theories of cognitive architectures addressed this issue by embedding models of problem solving within them. This thesis presents an extended account of human problem solving and describes its implementation within one such theory of cognitive architecture--ICARUS. The document begins by reviewing the standard theory of problem solving, along with how previous versions of ICARUS have incorporated and expanded on it. Next it discusses some limitations of the existing mechanism and proposes four extensions that eliminate these limitations, elaborate the framework along interesting dimensions, and bring it into closer alignment with human problem-solving abilities. After this, it presents evaluations on four domains that establish the benefits of these extensions. The results demonstrate the system's ability to solve problems in various domains and its generality. In closing, it outlines related work and notes promising directions for additional research. / Dissertation/Thesis / M.S. Computer Science 2011

Orientador: Ermínia de Lourdes Campello Fanti / Banca: Oziride Manzoli Neto / Banca: Maria Gorete Carreira Andrade / Resumo: Para todo grupo G infinito, finitamente gerado, pode-se obter para o invariante algébrico "end", mais precisamente o número de ends e(G), uma fórmula cohomológica 1-dimensional. O principal objetivo deste trabalho é apresentar, sob certas hipóteses, uma fórmula cohomológica 1-dimensional para o invariante algébrico e(G,H), definido por Scott e Houghton, onde H é um subgrupo de G (Teorema de Swarup). Para tanto, o conceito de subconjunto H-quase invariante de G e resultados como a interpretação do grupo de cohomologia H1(G,M) em termos de derivações (à direita), onde M é um ZG-módulo, e o Lema de Shapiro, são resultados imprescindíveis. Algumas relações desses invariantes com ends de espaços são também apresentadas. / Abstract: For all infinite group G, finitely generated, one can obtain for the algebric invariant "end", more precisely the number of ends e(G), a cohomological 1-dimensional formula. The main objective of this work is to present, under certain hypotheses, a cohomological 1-dimensional formula for the algebric invariant e(G,H), defined by Scott and Houghton, where H is a subgroup of G (Swarup's Theorem). In order to do so, the concept of subset H-almost invariant of G and results like the interpretation of the cohomological group H1(G,M) in terms of derivations (to the right), where M is a ZG-module, and the Shapiro's Lemma, are fundamental results. Some relations of these invariants with space ends are also presented. / Mestre

O estudo do princípio da autonomia, conceito central na filosofia moral de Kant, permite compreender a origem da lei moral. A fórmula da autonomia prescreve que a lei moral é fruto da vontade e não depende de fatores externos: nós somos colegisladores de uma lei a que nos submetemos. A tese da unidade do imperativo categórico assevera que o imperativo categórico é uno e apenas um. Portanto, ao aplicar-se o imperativo categórico na política através da fórmula da lei universal estáse efetivamente a aplicar o princípio supremo da moralidade num contexto sócio político. A fórmula do reino dos fins faz com que esta associação seja mais presente, principalmente através da analogia entre súditos e soberanos de uma lei moral, que na política se dá através da relação entre chefe de Estado e cidadãos. Com o conceito de \'reino dos fins\' dá-se um passo em frente e a ideia de co-legislação é aplicada, segundo cremos, por um processo sócio-político na Paz Perpétua. Por sua vez, expõese o pensamento de vários autores que interpretam conceitos morais de um ponto de vista político. No entanto, nos afastamos dessa interpretação por reconhecermos que na Filosofia Moral kantiana não existe uma evidência suficiente para essa asserção. A relação é, por isso, inversa à proposta pela tradição construtivista: a moralidade está presente na Filosofia Política. Ela pode, com efeito, coincidir completamente com a política quando se trata dos princípios fundamentais da política. Ou pode servir como um impedimento a certas ações que, embora não sejam de teor moral, estejam em contradição com ela. Tal como acontece com os imperativos hipotéticos. A razão prudencial, pragmática ou técnica, deve dobrar seus joelhos perante a razão prática pura. Propõe-se, assim, um paralelo com conceitos desenvolvidos na Paz Perpétua, designadamente com a ideia de um modo de governo republicano (constituição republicana), onde os seus membros têm de participar de uma legislação, e com o político moral, considerado o agente responsável por aplicar a moral (razão prática pura). / The study of the principle of autonomy, a central concept in Kant\'s moral philosophy, allow us to understand the origin of the moral law. The formula of autonomy dictates that the moral law is the result of the will and does not depend on external factors: we are co-legislators of a law that we submit to ourselves. The thesis of the unity of the categorical imperative asserts that the categorical imperative is one and only one. Therefore, when applying the categorical imperative in politics through the formula of universal law is being effectively applied by the supreme principle of morality in a sociopolitical context. The formula of the kingdom of ends makes this association more present, mainly through the analogy between sovereigns and subjects of a moral law, which in politics is through the relationship between the head of state and citizens. With the concept of \'kingdom of ends\' a step ahead is done and the idea of co-legislation is applied, giving us, we believe, by a socio-political process in the Perpetual Peace. In turn, we expose the thought of many authors who interpret moral concepts from a political point of view. However, we drifted apart this interpretation because we recognize that in Kant\'s Moral Philosophy there isn\'t a strong evidence for this assertion. The relationship is, therefore, reverse to the proposal by the Constructivist tradition: the morality is present in Political Philosophy. It may, in fact, match completely with the politics when it comes to the fundamental principles of politics. Or can serve as a constraint to certain actions that, while not of moral content, are in contradiction with it. As occurs with the hypothetical imperatives. The prudential reason, pragmatic or technical, should double their \'knees\' before the pure practical reason. Therefore we propose a parallel with concepts developed in Perpetual Peace, namely the idea of a republican form of government (republican constitution), where its members have to participate in a common legislation, and the moral politician, considered the agent responsible for applying morale (pure practical reason).

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This doctoral dissertation has as main goal to reconstruct and to analyse central aspects of Grice s practical philosophy, in special, his conception of eudaimonia. My central proposal is to show that there is an inconsistency in the system of ends proposed by Grice in order to treat the philosophical problem of the nature of eudaimonia. In Aspects of Reason, Grice will determine what the nature of reason consists in and the philosophical consequences that follow from its adequate determination. Grice will discuss the relations between theoretical and practical reasoning, in order to maintain that theoretical and practical reason are developments of a single fundamental conception of reason. One of Grice s main thesis, after discussing the structure of rationality and presenting the so called theoretical and practical acceptabilities which are treated as special kinds of arguments that contains a basic rationality operator , is to defend that eudaimonia should be understood as an inclusive end. Furthermore, Grice presents a system of ends with formal features that will help the individuals in the search for their own eudaimonia. This system of ends would have as a function the organization of the constitutive ends of eudaimonia, in such a way that eudaimonia could be considered as a set of ends. In this view, the system of ends should ensure, among other things, the stability and consistence of the set of eudaimonia. However, by maintaining that eudaimonia is an inclusive end, and consequently a set of ends, Grice is inevitably led to an inconsistency, ignored by him. The treatment of eudaimonia as an end and simultaneously as a set of ends implies a formal problem. According to one of the axioms of the set theory, the Axiom of Regularity, a set cannot be a member of itself. So, I intend to defend that Grice s systems of ends, but to criticize his thesis that eudaimonia can be considered as a set of ends. My alternative proposal is that the best option is to treat eudaimonia through mereology, i.e., the theory of the whole and their parts. / Esta tese de doutorado tem como objetivo principal reconstruir e analisar aspectos centrais da filosofia prática de Grice, em especial, a sua concepção de eudaimonia. Minha proposta central é mostrar que há uma inconsistência no sistema de fins proposto por Grice para tratar do problema filosófico da eudaimonia. Em Aspects of Reason, Grice irá determinar em que consiste a natureza da razão e as consequências filosóficas que podemos retirar a partir de sua adequada determinação. Grice buscará discutir as relações entre racionalidade teórica e racionalidade prática, com o intuito de sustentar que razão teórica e razão prática são desdobramentos de uma única concepção fundamental de razão. Uma de suas teses principais, após discutir a estrutura da racionalidade e apresentar as chamadas aceitabilidades teóricas e práticas as quais são consideradas como tipos especiais de argumentos que contêm um operador básico de racionalidade , é defender que eudaimonia deve ser entendida como um fim inclusivo. Além disso, Grice apresenta um sistema de fins com características formais que auxiliará os indivíduos na busca pela sua própria eudaimonia. Este sistema de fins teria como função organizar os fins constituvos da eudaimonia, de modo que eudaimonia pudesse ser considerada como um conjunto de finalidades. O sistema de fins, assim, deveria, dentre outras coisas, garantir a estabilidade e consistência do conjunto de eudaimonia. Porém, ao sustentar que eudaimonia é um fim inclusivo e, como consequência, um conjunto de fins, Grice é inevitavelmente levado a uma inconsistência, a qual ele desconsidera. O tratamento da eudaimonia como um fim e como um conjunto de fins implica um problema formal. Conforme um dos axiomas básicos da teoria dos conjuntos, o Axioma da Regularidade, um conjunto não pode ser membro dele mesmo. Assim, pretendo defender o sistema de fins de Grice, mas atacar a sua tese de que eudaimonia possa ser considerada como um conjunto de fins. Minha proposta alternativa é que a melhor opção é tratar a eudaimonia por meio da mereologia, isto é, a teoria do todo e das partes.

Le génome du virus de l’Hépatite C est constitué d’un ARN monocaténaire linéaire de polarité positive (+). Les interactions ARN-ARN prennent une place essentielle dans la régulation du cycle viral.La synthèse de l’ARN est réalisée par l’ARN-polymérase ARN-dépendante (RdRp) codée par le virus. Elle serait initiée à l’extrémité 3’ des molécules à répliquer. Un ARN génomique complémentaire de polarité négative (-) est d’abord synthétisé. Il sert ensuite de matrice pour la production des brins génomiques. Les mécanismes qui président au recrutement de la polymérase et à l’initiation de la synthèse d’ARN restent, aujourd’hui, mal connus.Les structures ARN présentes aux extrémités 3’ et leurs rôles ont donc étés étudiés au cours des travaux de cette thèse. Au niveau de l’extrémité 3’ de l’ARN (+), la dimérisation a été montrée indispensable à la réplication du virus in cellulo. Ces travaux ont par la suite permis de caractériser par gel retard et cryo-microscopie la dimérisation des ARN génomiques en solution. Au niveau de l’extrémité 3’ de l’ARN (-), la dimérisation de deux molécules a également pu être caractérisée par des approches biochimiques et biophysiques. Par ailleurs la présence d’un G-quadruplex introduit un remaniement conformationnel qui se révèle indispensable à une synthèse performante de l’ARN. De manière similaire au brin génomique, la dynamique structurale résultante de ces interactions semble donc nécessaire à une réplication efficace de l’ARN par la RdRp.Les résultats obtenus soulignent l’importance de la dimérisation et des variations conformationnelles prisent aux extrémités 3’ pour la réplication de l’ARN. Ces données ouvrent alors la voie vers de nouvelles perspectives quant à la compréhension des mécanismes qui président au fonctionnement de la polymérase du VHC. / The hepatitis C virus genome consists of a linear positive sens (+) single-stranded RNA. RNA-RNA interactions play an essential role in the regulation of the viral cycle.RNA synthesis is performed by the RNA-dependent RNA-polymerase (RdRp) encoded by the virus. It would be initiated at the 3 'end of the molecule to be replicated. A complementary genomic RNA of negative polarity (-) is first synthesized. It then serves as a matrix for the production of genomic strands. The mechanisms that govern the recruitment of the polymerase and the initiation of RNA synthesis remain poorly understood today.The RNA structures found at the 3 'ends and their roles have therefore been studied during the work of this thesis. At the 3 'end of the (+) RNA, dimerization was shown to be essential for replication of the virus in cellulo. This work made it possible to characterize by gel shift assay and cryo-microscopy the dimerization of the genomic RNAs in solution. At the 3 'end of (-) RNA, the dimerization of two molecules could also be characterized by biochemical and biophysical approaches. Moreover, the presence of a G-quadruplex introduces a conformational reshuffle which proves to be indispensable for an efficient RNA synthesis. Similarly to the genomic strand, the resulting structural dynamics of these interactions appear to be necessary for efficient RNA replication by the RdRp.The results obtained here underline the importance of dimerization and conformational variations at the 3 'ends for RNA replication. These data then open the way to new perspectives on understanding the mechanisms that govern the functioning of HCV polymerase.

Planejamento probabilístico lida com a tomada de decisão sequencial em ambientes estocásticos e geralmente é modelado por um Processo de Decisão Markoviano (Markovian Decision Process - MDP). Um MDP modela a interação entre um agente e o seu ambiente: em cada estágio, o agente decide executar uma ação, com efeitos probabilísticos e um certo custo, que irá produzir um estado futuro. O objetivo do agente MDP é minimizar o custo esperado ao longo de uma sequência de escolhas de ação. O número de estágios que o agente atua no ambiente é chamado de horizonte, o qual pode ser finito, infinito ou indefinido. Um exemplo de MDP com horizonte indefinido é o Stochastic Shortest Path MDP (SSP MDP), que estende a definição de MDP adicionando um conjunto de estados meta (o agente para de agir ao alcançar um estado meta). Num SSP MDP é feita a suposição de que é sempre possível alcançar um estado meta a partir de qualquer estado do mundo. No entanto, essa é uma suposição muito forte e que não pode ser garantida em aplicações práticas. Estados a partir dos quais é impossível atingir a meta são chamados de becos-sem-saída. Um beco-sem-saída pode ser evitável ou inevitável (se nenhuma política leva do estado inicial para a meta com probabilidade um). Em trabalhos recentes foram propostas extensões para SSP MDP que permitem a existência de diferentes tipos de beco-sem-saída, bem como algoritmos para resolvê-los. No entanto, a detecção de becos-sem-saída é feita utilizando: (i) heurísticas que podem falhar para becos-sem-saída implícitos ou (ii) métodos mais confiáveis, mas que demandam alto custo computacional. Neste projeto fazemos uma caracterização formal de modelos de planejamento probabilístico com becos-sem-saída. Além disso, propomos uma nova técnica para detecção de becos-sem-saída baseada nessa caracterização e adaptamos algoritmos de planejamento probabilístico para utilizarem esse novo método de detecção. Os resultados empíricos mostram que o método proposto é capaz de detectar todos os becos-sem-saída de um dado conjunto de estados e, quando usado com planejadores probabilísticos, pode tornar esses planejadores mais eficientes em domínios com becos-sem-saída difíceis de serem detectados / Probabilistic planning deals with sequential decision making in stochastic environments and is modeled by a Markovian Decision Process (MDP). An MDP models the interaction between an agent and its environment: at each stage, the agent decides to execute an action, with probabilistic effects and a certain cost which produces a future state. The purpose of the MDP agent is to minimize the expected cost along a sequence of choices. The number of stages that the agent acts in the environment is called horizon, which can be finite, infinite or undefined. An example of MDP with undefined horizon is the Stochastic Shortest Path MDP, which extends the definition of MDP by adding a set of goal states (the agent stops acting after reaching a goal state). In an SSP MDP the assumption is made that it is always possible to achieve a goal state from every state of the world. However, this is a very strong assumption and cannot be guaranteed in practical applications. States from which it is impossible to reach the goal are called dead-ends. A dead-end may be avoidable or unavoidable (when no policy leads from the initial state to the goal with probability one). Recent work has proposed extensions to SSP MDP that allow the existence of different types of dead-ends as well as algorithms to solve them. However, the detection of dead-end is done using: (i) heuristics that may fail to detect implicitly dead-ends or (ii) more reliable methods that require a high computational cost. In this project we make a formal characterization of probabilistic planning models with dead-ends. In addition, we propose a new technique for dead-end detection based on this characterization and we adapt probabilistic planning algorithms to use this new detection method. The empirical results show that the proposed method is able to detect all dead-ends of a given set of states and, when used withprobabilistic planners, can make these planners more efficient in domains with difficult to detect dead-ends.