MELO, Heitor Alves de. Propriedades eletrônicas de pontos quânticos contendo muitos elétrons. 2010. 75 f. : Dissertação (mestrado) - Universidade Federal do Ceará, Centro de Ciências, Departamento de Física, Fortaleza, 2010 . / Submitted by francisco lima (admir@ufc.br) on 2012-11-27T15:20:10Z No. of bitstreams: 1 2010_hadmelo.pdf: 2475149 bytes, checksum: f2b733568c55c95683fc14e493c5ab31 (MD5) / Approved for entry into archive by Nirlange Queiroz(nirlange@gmail.com) on 2015-09-18T12:10:21Z (GMT) No. of bitstreams: 1 2010_hadmelo.pdf: 2475149 bytes, checksum: f2b733568c55c95683fc14e493c5ab31 (MD5) / Made available in DSpace on 2015-09-18T12:10:21Z (GMT). No. of bitstreams: 1 2010_hadmelo.pdf: 2475149 bytes, checksum: f2b733568c55c95683fc14e493c5ab31 (MD5) / This work investigates the eletronic properties of semiconductor quantum dots in which there are many electrons con ned. In particular, we study Si and Ge quantum dots embedded in dielectric matrices (SiO2 e HfO2). The theoretical methos used to calculate the total energy of N electrons con ned in quantum dots is based on a simpli ed version of the Hartree-Fock method. In this model, the total energy is obtained from single-particle wavefunctions and eigen-energies. The obtained results show that the total energy in Ge quantum dots are always larger than in Si ones. The reason is the smaller electron e ective mass in Ge, which raises the energies of the con ned states. As for the role of the dielectric matrix, the total energy is always larger for SiO2 than for HfO2. Physically, this e ect is caused by the fact that SiO2 has larger con nement barriers (3.2 eV) than HfO2 (1.5 eV). Smaller barriers favor larger spatial extent of the wavefunctions, decreasing the repulsion energy of the con ned electrons. The chemical potential and additional energy was also calculated as function of the number of con ned electrons. It was observed that the chemical potential of Ge quantum dots are always larger than Si ones, but the role of the dielectric matrix is inverted. The chemical potential for HfO2 is larger than for SiO2. With respect to the additional energy, we observed that this quantity strongly oscillates within the range 0 to 0.4 eV for cases. If one takes into account that the Coulomb blockade phenomena is only observed for additional energies much larger the thermal enegy (of the order of 3=2kBT), this phenomena can only be observed for the case where there are only a few electrons con ned in the quantum dots. / Este trabalho dedica-se ao estudo das propriedades eletrônicas de pontos quânticos semicondutores contendo muitos el etrons con nados. Em particular, ser~ao investigados pontos quânticos de Si e Ge imersos em matrizes diel etricas (SiO2 e HfO2). O m etodo te orico utilizado para calcular a energia total de um sistema de N el etrons con nados baseia-se numa vers~ao simpli cada do m etodo de Hartree-Fock. Neste modelo a energia total e calculada a partir das fun ções de onda e estados de energia de uma unica part cula. Os resultados obtidos mostram que a energia total em pontos quânticos de Ge s~ao em geral maiores que em pontos quânticos de Si, independentemente do n umero de el etrons con nados. Isto acontece devido a massa efetiva menor dos el etrons no Ge que aumentam as energia de con namento. Em rela ção ao papel das barreiras diel etricas, a energia total e sempre maior nos casos em que o ponto quântico est a envolvido por SiO2. Fisicamente, isto se deve ao fato de que a barreira de con namento do SiO2 (3.2 eV) e maior que a do HfO2 (1.5 eV). Barreiras mais baixas favorecem o aumento da extensão espacial das funções de onda, reduzindo a repulsão coulombiana dos el etrons con nados. Calculouse tamb em o potencial quí mico dos pontos quânticos em fun ção do n umero de el etrons con nados, e a energia adicional necess aria para aprisionar mais um el etron nos pontos quânticos. Veri cou-se que o potencial qu mico dos pontos quânticos de Ge são sempre maiores que nos de Si, por em o potencial qu mico para pontos quânticos envoltos em HfO2 são sempre maiores que no caso do SiO2. Em relação a energia adicional, observa-se que esta quantidade apresenta fortes oscilações e que varia entre 0 e 0.4 eV para todos os casos estudados. Se levarmos em conta que o fenômeno conhecido como bloqueio de Coulomb acontece quando a energia adicional e muito maior que a energia t ermica (da ordem de 3=2kBT), este fenômeno s o ser a observado quando houver poucos el etrons con nados nos pontos quânticos.

Dans cette thèse, nous étudions l’adéquation de l’architecture distribuée des processeurs pluricoeurs avec les besoins des concepteurs de systèmes temps réels avioniques. Nous proposons d’abord une analyse détaillée d’un processeur sur étagère (COTS), le KALRAY MPPA®-256, et nous identifions certaines de ses ressources partagées comme étant les goulots d’étranglement limitant à la fois la performance et la prédictibilité lorsque plusieurs applications s’exécutent. Pour limiter l’impact de ces ressources sur les WCETs, nous définissons formellement un modèle d’exécution isolant temporellement les applications concurrentes. Son implantation est réalisée au sein d’un hyperviseur offrant à chaque application un environnement d’exécution isolé et assurant le respect des comportements attendus en ligne. Sur cette base, nous formalisons la notion de partition comme l’association d’une application avec un budget de ressources matérielles. Dans notre approche, les applications s’exécutant au sein d’une partition sont garanties d’être temporellement isolées des autres applications. Ainsi, étant donné une application et son budget associé, nous proposons d’utiliser la programmation par contraintes pour vérifier automatiquement si les ressources allouées à l’application sont suffisantes pour permettre son exécution de manière satisfaisante. Dans le même temps, dans le cas où un budget est effectivement valide, notre approche fournit un ordonnancement et un placement complet de l’application sur le sous-ensemble des ressources du processeurallouées à sa partition. / In this thesis, we study the suitability of the distributed architecture of many-core processors for the design of highly constrained real-time systems as is the case in avionics. We firstly propose a thorough analysis of an existing COTS processor, namely the KALRAY MPPA®-256, and we identify some of its shared resources to be paths of interference when shared among several applications. We provide an execution model to restrict the access to these resources in order to mitigate their impact on WCETs and to temporally isolate co-running applications. We describe in detail how such an execution model can be implemented with a hypervisor which practically provides the expected property of temporal isolation at run-time. Based on this, we formalize a notion of partition which represents the association of an application with a resource budget. In our approach, an application placed in a partition is guaranteed to be temporally isolated from applications placed in other partitions. Then, assuming that applications and resource budgets are given,we propose to use constraint programming in order to verify automatically whether the amount of resources requested by a budget is sufficient to meet all of the application’s constraints. Simultaneously, when a budget is valid, our approach computes a schedule of the application on the subset of the processor’s resources allocated to it.

As próximas gerações de processadores many-core exigem que novas abordagens no projeto de arquitetura de processadores sejam propostas. Neste novo contexto, as redes de comunicação intra-chip são importantes para garantir o desempenho dos programas. Soluções tradicionais de interconexão possuem limites físicos que comprometem a escalabilidade e o desempenho no processamento de aplicações paralelas de diversos tipos. A alternativa apontada pelo estado da arte é a Network-on-Chip (NoC) composta por roteadores e outros elementos de rede capazes de prover comunicação escalável e de alto desempenho. No entanto, as cargas de trabalho geram padrões de comunicação diferentes que podem influenciar no desempenho da rede. Existem pesquisas que abordam metodologias de projeto dedicado de NoCs em função de domínios de aplicações específicos. Apesar de uma NoC dedicada possuir um alto desempenho, cargas de trabalho paralelas geram padrões de comunicação coletiva que mudam dinamicamente. Com o objetivo de aumentar a flexibilidade de redes-em-chip, trabalhos correlatos utilizam conceitos de computação reconfigurável para aumentar a capacidade da arquitetura da NoC se adaptar em função de padrões de comunicação. Alguns trabalhos focam na programação de FPGAs e outros em ASICs polimórficos. O objetivo desta tese é propor uma arquitetura de Network-on-Chip que suporte múltiplos clusters de núcleos de processamento através de roteadores programáveis e de topologias reconfiguráveis. Cada roteador é composto por uma chave crossbar reconfigurável capaz de implementar topologias dinamicamente através do uso de um segundo nível de reconfiguração. Os roteadores possuem processadores de rede que aumentam a flexibilidade e a capacidade da NoC se adaptar ao padrão de comunicação através de programas que monitoram e gerenciam a rede. Portanto, a contribuição da tese é a Arquitetura de NoC Programável Baseada em Múltiplos Clusters de Cores. Os resultados baseados em modelos analíticos e de simulação, e cargas de trabalho artificiais e naturais, mostram que a arquitetura da NoC possui um alto desempenho e vazão de pacotes, proporcionados pela adaptação de topologias e redução da influência da rede na comunicação. A ocupação em FPGA mostra que os roteadores programáveis possuem tamanho similares a NoCs com arquiteturas tradicionais para gerenciamento de mesma quantidade de núcleos. A menor utilização de buffers de entrada resulta em uma melhor eficiência no consumo de potência e energia. Portanto, através dos modelos de projeto e avaliação foi possível verificar através dos resultados que a arquitetura da MCNoC é uma alternativa para suportar padrões de comunicações coletivas. / For the next generation of many-core processors, new design methodologies must be proposed. In this context, on-chip interconnections are important to assure the program performance. Traditional approaches of interconnections have physical constraints that reduce the scalability and performance to process parallel applications. The state-of-theart points out to the Network-on-Chip (NoC), which consists of routers and other network devices capable of increasing the communication scalability and performance. However, workloads produce different types of communication patterns, which can influence the network performance. There are research works that explore applicationspecific NoC design to response the demand on specific workloads. Although a dedicated NoC has a high performance, parallel workloads have different collective communication patterns. In order to increase the flexibility of NoCs, related works use concepts of reconfigurable computing to add architecture adaptability to support dynamic communication patterns. Some works focus on FPGA-based reconfiguration and others on polymorphic ASICs. The goal of this thesis is to propose an alternative Programmable Multi-Cluster NoC architecture. Each router consists of a reconfigurable crossbar switch capable of implementing dynamic topologies through a second reconfiguration level. The routers have network processors that increase the flexibility and the NoC adaptability through management programs in order to support different workloads. Therefore, the contribution of this thesis is the following: A Programmable Multi-Cluster NoC (MCNoC) architecture. Based on analytical and simulation models, and artificial and natural workloads, results show the high performance and throughput for the proposed NoC architecture, due to the adaptable topologies and low network latency impact. Results based on FPGA shows a similar component utilization considering the proposed programmable NoC relative to conventional NoC architectures for the same number of processing cores. The low utilization of input buffers improves the efficiency of power and energy consumption. Therefore, through design and evaluation models, the NoC proposal was verified and the results point out the MCNoC as an alternative architecture to support collective communication patterns.

As próximas gerações de processadores many-core exigem que novas abordagens no projeto de arquitetura de processadores sejam propostas. Neste novo contexto, as redes de comunicação intra-chip são importantes para garantir o desempenho dos programas. Soluções tradicionais de interconexão possuem limites físicos que comprometem a escalabilidade e o desempenho no processamento de aplicações paralelas de diversos tipos. A alternativa apontada pelo estado da arte é a Network-on-Chip (NoC) composta por roteadores e outros elementos de rede capazes de prover comunicação escalável e de alto desempenho. No entanto, as cargas de trabalho geram padrões de comunicação diferentes que podem influenciar no desempenho da rede. Existem pesquisas que abordam metodologias de projeto dedicado de NoCs em função de domínios de aplicações específicos. Apesar de uma NoC dedicada possuir um alto desempenho, cargas de trabalho paralelas geram padrões de comunicação coletiva que mudam dinamicamente. Com o objetivo de aumentar a flexibilidade de redes-em-chip, trabalhos correlatos utilizam conceitos de computação reconfigurável para aumentar a capacidade da arquitetura da NoC se adaptar em função de padrões de comunicação. Alguns trabalhos focam na programação de FPGAs e outros em ASICs polimórficos. O objetivo desta tese é propor uma arquitetura de Network-on-Chip que suporte múltiplos clusters de núcleos de processamento através de roteadores programáveis e de topologias reconfiguráveis. Cada roteador é composto por uma chave crossbar reconfigurável capaz de implementar topologias dinamicamente através do uso de um segundo nível de reconfiguração. Os roteadores possuem processadores de rede que aumentam a flexibilidade e a capacidade da NoC se adaptar ao padrão de comunicação através de programas que monitoram e gerenciam a rede. Portanto, a contribuição da tese é a Arquitetura de NoC Programável Baseada em Múltiplos Clusters de Cores. Os resultados baseados em modelos analíticos e de simulação, e cargas de trabalho artificiais e naturais, mostram que a arquitetura da NoC possui um alto desempenho e vazão de pacotes, proporcionados pela adaptação de topologias e redução da influência da rede na comunicação. A ocupação em FPGA mostra que os roteadores programáveis possuem tamanho similares a NoCs com arquiteturas tradicionais para gerenciamento de mesma quantidade de núcleos. A menor utilização de buffers de entrada resulta em uma melhor eficiência no consumo de potência e energia. Portanto, através dos modelos de projeto e avaliação foi possível verificar através dos resultados que a arquitetura da MCNoC é uma alternativa para suportar padrões de comunicações coletivas. / For the next generation of many-core processors, new design methodologies must be proposed. In this context, on-chip interconnections are important to assure the program performance. Traditional approaches of interconnections have physical constraints that reduce the scalability and performance to process parallel applications. The state-of-theart points out to the Network-on-Chip (NoC), which consists of routers and other network devices capable of increasing the communication scalability and performance. However, workloads produce different types of communication patterns, which can influence the network performance. There are research works that explore applicationspecific NoC design to response the demand on specific workloads. Although a dedicated NoC has a high performance, parallel workloads have different collective communication patterns. In order to increase the flexibility of NoCs, related works use concepts of reconfigurable computing to add architecture adaptability to support dynamic communication patterns. Some works focus on FPGA-based reconfiguration and others on polymorphic ASICs. The goal of this thesis is to propose an alternative Programmable Multi-Cluster NoC architecture. Each router consists of a reconfigurable crossbar switch capable of implementing dynamic topologies through a second reconfiguration level. The routers have network processors that increase the flexibility and the NoC adaptability through management programs in order to support different workloads. Therefore, the contribution of this thesis is the following: A Programmable Multi-Cluster NoC (MCNoC) architecture. Based on analytical and simulation models, and artificial and natural workloads, results show the high performance and throughput for the proposed NoC architecture, due to the adaptable topologies and low network latency impact. Results based on FPGA shows a similar component utilization considering the proposed programmable NoC relative to conventional NoC architectures for the same number of processing cores. The low utilization of input buffers improves the efficiency of power and energy consumption. Therefore, through design and evaluation models, the NoC proposal was verified and the results point out the MCNoC as an alternative architecture to support collective communication patterns.

nÃo hà / Este trabalho dedica-se ao estudo das propriedades eletrÃnicas de pontos quÃnticos semicondutores contendo muitos elÃtrons confinados. Em particular, serÃo investigados semicondutores contendo muitos elÃtrons confinados. Em particular, serÃo investigados pontos quÃnticos de Si e Ge imersos em matrizes dielÃtricas (SiO2 e HfO2). O mÃtodo teÃrico utilizado para calcular a energia total de um sistema de N elÃtrons confinados baseia-se numa versÃo simplificada do mÃtodo de Hartree-Fock. Neste modelo a energia total e calculada a partir das funÃÃes de onda e estados de energia de uma Ãnica partÃcula Os resultados obtidos mostram que a energia total em pontos quÃnticos de Ge sÃo em geral maiores que em pontos quÃnticos de Si, independentemente do nÃmero de elÃtrons confinados. Isto acontece devido a massa efetiva menor dos elÃtrons no Ge que aumentam as energia de confinamento. Em relaÃÃo ao papel das barreiras dielÃtricas, a energia total à sempre maior nos casos em que o ponto quÃntico està envolvido por SiO2. Fisicamente, isto se deve ao fato de que a barreira de confinamento do SiO2 (3.2 eV) à maior que a do HfO2 (1.5 eV). Barreiras mais baixas favorecem o aumento da extensÃo espacial das funÃÃes de onda, reduzindo a repulsÃo coulombiana dos elÃtrons confinados. Calculou se tambÃm o potencial quÃmico dos pontos quÃnticos em funÃÃo do nÃmero de elÃtrons confinados, e a energia adicional necessÃria para aprisionar mais um elÃtron nos pontos quÃnticos. Verificou-se que o potencial quÃmico dos pontos quÃnticos de Ge sÃo sempre maiores que nos de Si, por em o potencial quÃmico para pontos quÃnticos envoltos em HfO2 sÃo sempre maiores que no caso do SiO2. Em relaÃÃo a energia adicional, observa-se que esta quantidade apresenta fortes oscilaÃÃes e que varia entre 0 e 0.4 eV para todos os casos estudados. Se levarmos em conta que o fenÃmeno conhecido como bloqueio de Coulomb acontece quando a energia adicional à muito maior que a energia tÃrmica (da ordem de 3=2kBT), este fenÃmeno sÃo serà observado quando houver poucos elÃtrons confinados nos pontos quÃnticos. / This work investigates the electronic properties of semiconductor quantum dots in which there are many electrons confined. In particular, we study Si and Ge quantum dots embedded in dielectric matrices (SiO2 e HfO2). The theoretical method used to calculate the total energy of N electrons confined in quantum dots is based on a simplified version of the Hartree-Fock method. In this model, the total energy is obtained from single-particle wavefunctions and eigen-energies. The obtained results show that the total energy in Ge quantum dots are always larger than in Si ones. The reason is the smaller electron e effective mass in Ge, which raises the energies of the confined states. As for the role of the dielectric matrix, the total energy is always larger for SiO2 than for HfO2. Physically, this e effect is caused by the fact that SiO2 has larger confinement barriers (3.2 eV) than HfO2(1.5 eV). Smaller barriers favor larger spatial extent of the wavefunctions, decreasing the repulsion energy of the confined electrons. The chemical potential and additional energy was also calculated as function of the number of confined electrons. It was observed that the chemical potential of Ge quantum dots are always larger than Si ones, but the role of the dielectric matrix is inverted. The chemical potential for HfO2 is larger than for SiO2. With respect to the additional energy, we observed that this quantity strongly oscillates within the range 0 to 0.4 eV for cases. If one takes into account that the Coulomb blockade phenomena is only observed for additional energies much larger the thermal energy (of the order of 3/2kBT), this phenomena can only be observed for the case where there are only a few electrons confined in the quantum dots.

Orientador: Walter Alexandre Carnielli / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Filosofia e Ciências Humanas / Made available in DSpace on 2018-08-23T18:22:31Z (GMT). No. of bitstreams: 1 Matulovic_Mariana_D.pdf: 1191409 bytes, checksum: 5228f60f9fdb9f3a9df31d448de09ca2 (MD5) Previous issue date: 2013 / Resumo: O presente trabalho tem por objetivo explorar, em diversas vertentes, o caráter universal de uma ferramenta poderosa de prova, apta a ser utilizada em lógicas clássicas e não clássicas, em particular em lógicas multivaloradas proposicionais (determinísticas e não-determinísticas), em lógicas paraconsistentes, em lógicas modais e na Lógica de Primeira Ordem. Trata-se do Método de Prova de Anéis de Polinômios, que também pode, em princípio, ser visto do ponto de vista da semântica algébrica, desenvolvido inicialmente em (Carnielli 2005b). O método traduz fórmulas de uma lógica específica em polinômios (em geral finitos, mas podendo ser infinitos) com coeficientes em corpos finitos, e transforma o problema de se encontrar demonstrações no correlato algébrico da busca de soluções de sistemas de equações polinomiais. Esta universalidade do método possibilita a abertura de diversas linhas de pesquisa, sendo a questão da verofuncionalidade e suas generalizações uma delas. Outras linhas de pesquisa são: possibilidades de se investigar enfoques alternativos da complexidade computacional, prova automática de teoremas, métodos heurísticos em lógica e correlações entre álgebra e lógica. Este trabalho analisa e compara sistemas de anéis de polinômios para sistemas com verofuncionalidade generalizada, como no caso das semânticas não-determinísticas, e ainda em sistemas onde a verofuncionalidade é perdida, tais como em sistemas multivalorados reduzidos a bivalorados através da conhecida redução de Suszko. O método de anéis de polinômios, além de poderoso e elegante em sua aparente simplicidade, constitui ainda um ótimo instrumento pedagógico. Em relação á lógica clássica, definimos um anel de polinômios para a Lógica de Primeira Ordem, fundamentado em um novo domínio que opera com somas e produtos infinitos, o qual se denomina domínio de séries generalizadas fechado por produtos. Finalmente, procuramos avaliar todas as potencialidades do método, principalmente no aspecto inerente á questão de se poder pensar em uma característica unificadora na medida que utiliza o mesmo viés matemático para traduzir diferentes sistemas lógicos em variedades algébricas similares. Além disso, analisamos as interrelações do método com respeito a lógica algébrica (ou álgebra da lógica), e avaliamos suas perspectivas / Abstract: This investigation aims to explore, in various aspects, the universal character of a powerful proof method, able to be used in classical and non-classical logics, in particular in propositional many-valued logics (deterministic and non- deterministic) in paraconsistent logics, in modal logics and in First Order Logic. This is the Method of Polynomial Rings, which can also be considered as an algebraic semantics, initially developed in (Carnielli 2005b). The method translates logical formulas into specific polynomials (usually finite, but sometimes infinite) with coefficients infinite fields, and transforms the problem of finding proofs in the search for solutions of systems of polynomial equations. This universality of the method enables the opening of several research lines, in particular the issue of truth-functionality and its generalizations. Other lines of research are: the possibilities of investigating alternative approaches of computational complexity, automatic theorem proving, heuristic methods in logic and correlations between algebra and logic. This study compares and analyzes the polynomial ring systems for systems with generalized truth-functionality, as in the case of non- deterministic semantic and even in systems where truth-functionality is lost, such as those many-valued systems reduced to bivalued by means of the so-called Suszko reduction. The method of polynomial rings, besides being a powerful and elegant apparatus in its apparent simplicity, is still a great teaching tool. Regarding classical logic, we define the polynomial ring for First Order Logic , based on a new domain that operates on sums and infinite products, called domain of generalized series closed under products. Finally, we evaluate the full potential of the method, especially in what concerns the question of obtaining a unifying feature that uses the same mathematical basis to translate different logical systems on similar algebraic varieties. Furthermore, we address the connections of the method with respect to algebraic logic (algebra of logic), and evaluate their perspectives / Doutorado / Filosofia / Doutora em Filosofia

The purpose of this study was to investigate the possibility to measure speed of a vehicle usingimage correlation. It was identified that a new solution of measuring the speed of a vehicle, astoday’s solution does not give the True Speed Over Ground, would open up possibilities of highprecision driving applications. It was also the intention to evaluate the performance of theproposed algorithm on a multicore platform. The study was commissioned by HalmstadUniversity.The investigation of image correlation as a method to measure speed of a vehicle was conductedby applying the proposed algorithm on a sequence of images. The result was compared toreference points in the image sequence to confirm the accuracy. The performance of the multicoreplatform was measured by counting the clock cycles it took to perform one measurement cycle ofthe algorithm.It was found out that using image correlation to measure speed has a positional accuracy of closeto a half percent. The results also revealed that one measurement cycle of the algorithm could beperformed in close to half a millisecond and the achieved parallel utilization of the multicoreplatform was close to eighty-seven percent.It was concluded that the algorithm performed well within the limit of acceptance. A conclusionabout the performance was that low execution time of a measurement cycle makes it possible toexecute the algorithm at a frequency of eighteen hundred Hertz. With a frequency that high, incombination with the camera settings proposed in the thesis, the algorithm would be able tomeasure speeds close to one thousand one hundred kilometers per hour.The authors recommend that future work should be focused on investigating the cameraparameters to be able to optimize both the memory and computational requirements of theapplication. It is also recommended to look closer at the algorithm and the possibilities ofdetecting transversal and angular changes as it would open up for other application areas,requiring more than just the speed.

This thesis describes the implementation of a source to source compiler that translates Fork language to REPLICA baseline language. The Fork language is a high-level programming language designed for the PRAM (Parallel Random Access Machine) model. The baseline language is a low-level parallel programming language for the REPLICA architecture which implements the PRAM computing model. To support the Fork language on REPLICA, a compiler that translates Fork to baseline is built.  The Fork to baseline compiler is built in compatibility with the Fork implementation for SB-PRAM. Moreover, the libraries that support Fork's features are built using baseline language.The evaluation result verifies that the features of the Fork language are supported in the implementation. The evaluation also shows the scalability of our implementation and shows that the overhead introduced by Fork-to-baseline translation is small.

A very important step in the art of cooking up models for the study of natural phenomena is the identification of the relevant ingredients. Taking into account too many details will lead to an overly complicated model, not at all useful to work with, but neglecting some crucial elements will lead to an equally useless model. So it is often the case that the actual experimental situation presents unavoidable sources of local randomness, whilst the analysed phenomenon does not really rely on presence/absence of such imperfections. For some other set of phenomena, however, disorder can play a crucial role, and must be carefully taken into account. Such is for example the case in certain phases of matter, the spin-glass phase, or the many-body localised phase. In this thesis we explore disorder in both of these situations and also as a theoretical means of testing the regime of liquidity in certain two-dimensional highly frustrated magnetic models. The focus here is placed on classical Heisenberg models defined on lattices consisting of clusters all sites of which interact mutually pairwise. This natural way to introduce frustration has been known in the literature to lead to so-called Coulomb spin-liquids, the single class of classical spin-liquids acknowledged to exist so far in Heisenberg models. Here we show that in fact two different classes of classical spin-liquids can be obtained from similarly defined frustrated models. In one of these, algebraic correlations exist at $T=0$, similar to the Coulomb phase, but the system exhibits a rather different low$-T$ effective action from the Coulomb phase. In the other class, the spin-liquid has spin correlations that decay exponentially with distance, with a correlation length smaller than a lattice spacing even at $T=0$. One special effect of disorder in these models, considered in the form of dilution by non-magnetic impurities, is to nucleate local degrees of freedom, so-called orphans, which express the concomitant spin-liquid phase through their non-trivial fractionalisation. When the associated spin-liquid exhibit algebraic correlations, it is also possible to find new effective spin-glass models as an effective $T=0$ description for interactions between the orphans, leading to so-called `random Coulomb magnets'. One part of this thesis is devoted to the first study of these new models. This investigation consists mainly of Monte Carlo simulations and numerical solution of the relevant large$-n$ equations ($n$ being the number of spin components). A clear spin-glass transition for infinitely large coupling strength is determined for the case of spins with an infinite number of components. The results presented on the situation for a finite number of spin components are more of an exploratory character, and large-scale simulations with further optimization schemes to ensure equilibration are still required to locate the transition. The final investigation treated in this thesis deals with the dynamics in a quantum model with disorder displaying the many-body localized phase, where in addition a periodic drive is applied. For a certain range of driving frequencies and amplitudes, it was found recently that the many-body localized phase is robust. These pioneering studies restricted themselves to an analysis of the stability of such a phase in the long time limit, while very little was known about the dynamics towards the asymptotic fate. Our study focuses on this aspect, and analyses the different dynamical behaviors as one varies the driving parameters, so that the many-body localized phase survives or is destroyed by the driving. We discover that on the border between these two asymptotic fates, a new dynamical behavior emerges, where the system heats up at a very slow, logarithmic in time, rate. / Die Bestimmung der wichtigsten Bestandteile stellt einen sehr wichtigen Schritt in der Kunst des Erstellens von Modellen dar. Die Annahme von zu vielen Details ergibt ein sehr kompliziertes, zu nichts zu gebrauchendes Modell, doch die Vernachlässigung von bedeutenden Zusammenhängen führt ebenfalls zu einem unbrauchbaren Ergebnis. Es ist so z.B. häufig der Fall, dass ein Experiment unter dem Einfluss von unvermeindlichen lokalen Zufälligkeiten steht, die allerdings kaum einen Einfluss auf ein beobachtetes Phänomen haben. Für gewisse Phänomene spielt Unordnung jedoch eine wesentliche Rolle und sie muss sehr genau in Betracht gezogen werden. Das ist für bestimmte Phasen, wie beispielsweise Spinglas oder die Vielteilchen-Lokalisation, der Fall. In dieser Dissertation untersuchen wir ungeordnete Systeme, die solche Phasen aufweisen. Außerdem verwenden wir Unordnung als ein theoretisches Werkzeug für die Analyse von bestimmten `Spinflüssigkeiten' in zweidimensionalen Spinmodellen. Der Fokus liegt hierbei auf klassischen Heisenberg Modellen definiert auf Gittern, die aus einer Anordnung von Clustern bestehen, sodass jede einzelne paarweise Heisenberg-Wechselwirkung innerhalb eines Clusters stattfindet. Dadurch weist das System geometrische Frustration auf und in mehreren Fällen tritt eine sogennante Coulomb Spinflüssigkeit ---die bislang einzig bekannte Klasse von klassischen Spinflüssigkeit in Heisenberg Modellen--- auf. Wir zeigen, dass mindestens zwei weitere Arten von klassischen Spinflüssigkeiten in solchen Modellen zu finden sind. Für die eine Klasse sind Spinkorrelationen zu erwarten, die algebraisch mit der Entfernung bei $T=0$ abnehmen, ähnlich wie für eine Coulomb Phase. Diese neu entdeckte Spinflüssigkeit lässt sich jedoch von der Coulomb Phase durch eine neue effektive Tieftemperatur-Theorie unterscheiden. Für die andere Klasse von Spinflüssigkeiten sind die Spinkorrelationen kurzreichweitig, und selbst bei $T=0$ nehmen sie exponentiell ab, mit einer Korrelationslänge, die kleiner als ein Gitterabstand ist. Unordnung, in der Form von nicht-magnetischen Störstellen, kann lokale Freiheitsgrade entstehen lassen (diese werden in der Literatur auch als `Orphans', Waisen, bezeichnet). Die Orphans verweisen durch ihre `Fraktionierung' eindeutig auf die nicht trivialen Korrelationen der spinflüssigen Phase. Falls die Spinflüssigkeit algebraische Korrelationen aufweist, findet man auch langreichweitige Wechselwirkungen zwischen den Orphans bei $T=0$. Dies führt zu neuen Spinglasmodellen, sogenannten `Random Coulomb Magnets'. Ein Teil dieser Dissertation ist der Untersuchung solcher Modelle gewidmet. Diese Untersuchung besteht hauptsächlich aus Monte Carlo Simulationen und numerischer Lösung der relevanten Large-$n$ Gleichungen (wobei $n$ hier auf die Anzahl an Spinkomponenten hinweist). In dem Fall von Spins mit unendlich vielen Spinkomponenten können wir einen eindeutigen Spinglas Phasenübergang für eine unendlich große Kopplungsstärke bestimmen. Die entsprechenden Ergebnisse für den Fall von Spins mit einer endlichen Anzahl an Spinkomponenten sind von einem exploratorischen Charakter. Zusätzliche Simulationen, die möglicherweise weitere Optimierungsschema verwenden um Äquilibrium zu gewährleisten, sind noch von nöten um eine eindeutige Aussage über den Übergang in solchen Fällen zu treffen. Der letzte Teil dieser Dissertation widmet sich der Untersuchung der Dynamik eines ungeordneten Quantenmodells. Das ausgewählte Modell weist die sogennante Vielteilchen-lokalisierte Phase auf, und wir untersuchen insbesondere den Effekt eines periodischen Antriebs auf die Dynamik des Systems. Für eine bestimmte Auswahl der Antriebs-frequenz und -amplitude, wurde es bereits vor kurzem bewiesen, dass die Vielteilchen-lokalisierte Phase diese Störung übersteht. Unsere Studie ist darauf ausgelegt, wie sich die Dynamik des Systems durch Variation der Antriebsparameter ändert, so dass die Vielteilchen-lokalisierte Phase für lange Zeit entweder den Antrieb übersteht oder von ihm zerstört wird. Wir konnten dadurch entdecken, dass an der Grenze zwischen diesen beiden Fällen ein neues dynamisches Verhalten entsteht, bei der das System eine sehr langsame, logarithmisch mit der Zeit, Erwärmung aufweist.

The resource demand on embedded devices is constantly growing. This is caused by the sheer explosion of software based functions in embedded systems, that are growing far faster than the resources of the single-core and multi-core embedded processors. As one of the limitation is the computing power of the processors we need to explore ways to use this resource more efficiently. We identified that during the run-time of the embedded devices the resource demand of the software functions is permanently changing dependent on the device situation. To enable an embedded device to take advantage of this dynamic resource demand, the allocation of the software functions to the processor must be handled by a scheduler that is able to evaluate the resource demand of the software functions in relation to the device situation. This marks a change in embedded devices from static defined software systems to dynamic software systems. Above that we can increase the efficiency even further by extending the approach from a single device to a distributed or networked system (many-core system). However, existing approaches to deal with dynamic resource allocation are focused on individual devices and leave the optimization potential of manycore systems untouched. Our concept will extend the existing Hierarchical Asynchronous Multi-Core Scheduler (HAMS) concept for individual devices to many-core systems. This extension introduces a dynamic situation aware scheduler for many-core systems which take the current workload of all devices and the system-situation into account. With our approach, the resource efficiency of an embedded many-core system can be increased. The following paper will explain the architecture and the expected results of our concept.