Controlling the quantum states of charge (excitons) or spin-polarized carriers in semiconductor quantum dots (QDs) has been the focus of a considerable research effort in recent years due to the strong promise of using this approach to develop solid state quantum computing hardware. The long-term scalability of this type of quantum computing architecture is enhanced by the use of QDs emitting in the telecom band, which would exploit the established photonic infrastructure. This thesis reports the use of all optical infrared experimental techniques to control exciton dynamics in two different QD samples consisting of InAs/GaAs QDs and InAs/InP QDs within a planar microcavity. An infrared quantum control apparatus was developed and used to apply optimized shaping masks to ultrafast pulses from an optical parametric oscillator. Pulse shaping protocols designed to execute a two-qubit controlled-rotation operation on an individual semiconductor QD were demonstrated and characterized. The quantum control apparatus was then implemented in simultaneous single qubit rotations using two uncoupled, distant InAs/GaAs QDs. These optimal control experiments demonstrated high fidelity optical manipulation of exciton states in the two QDs using a single broadband laser pulse, representing a step forward on the path to a scalable QD architecture and showcasing the power of pulse shaping techniques for quantum control on solid state qubits. As an alternative to single QDs, which have very low optical signals, subsets of QDs within an ensemble can be used in quantum computing applications. To investigate the mediation of inhomogeneities in a QD ensemble, pump-probe experiments were performed on InAs/InP QDs within a dielectric Bragg stack microcavity. Two different excitation geometries showed that the angle dependence of the microcavity transmission allowed for the spectral selection of QD subsets with transition energies resonant with the cavity mode. The microcavity mitigated inhomogeneities in the ensemble while providing a basis for addressing QD subsets which could be used as distinguishable quantum bits. This thesis work shows significant advances towards an optical computing architecture using quantum states in semiconductor QDs.

Baigiamajame magistro darbe aprašyta apvaliosios medienos rietuvių fotonuotraukų analizė, siekiant įvertinti medienos rietuvių glaudumo koeficientą. Darbo tikslas – Įvertinti fotometrinio metodo taikymo apvaliosios medienos rietuvių glaudumo koeficiento nustatymui galimybes. Uždaviniai: • Įvertinti atsitiktinių ir sisteminių paklaidų dydžius, gaunamus apvaliosios medienos rietuvių glaudumo koeficientą, nustatant fotometriniu metodu. • Įvertinti fotometrinio metodo paklaidų priklausomybę nuo sortimentų rūšies. • Įvertinti paklaidų priklausomybę nuo medienos rietuvių glaudumo. Tyrimo objektas – į transporto priemonę sukrauti apvaliosios madienos popiermedžiai. Tyrimo metodika Darbe naudoti mokslinio tyrimo metodai: • Dokumentų analizė; • Vaizdų analizė; • Statistinė analizė; • Loginė analizė. Darbo rezultatai – mano pasirinktas fotometrinis metodas, apvaliosios madienos rietuvių glaudumo koeficientui įvertinti, gali būti taikomas. Paklaidos yra daromos tačiau jos nėra esminės. Iš pasirnktų trijų analizuojamojo vaizdo išskyrimo būdų tiksliausi rezultatai buvo stačiakampio forma išskirtas vaizdas. / Digital photographs of spruce and birch bundles were analised by photometric method using ArcView GIS 3.2. program to determine stacking coefficient of wood in the work. The main aim – to determine ability of photometric method to avaluate stacking coefficient of bundles. The main tasks: • To determine randon and systematic bias of photometric method to estimating stacking of wood bundles. • To determine volume of bias, using photometric method, dependents of roundwood species. • To aveluate dependense of errors in stacking coefficients of bundles volume. Research object. –solid wood which is loaded in a bundles of a truck. Methods: • Dokument analysis; • Image analysis; • Statistic analysis; • Logical analysis. Calculations were made using software ArcView GIS 3.2., STATISTICA v6.0 and EXCEL. The main results. photometric method can be applied to timber stacking precision ratios. Articularly accurate are obtained with the bundle of analyzing image maked rectangle.

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The CanX-4 and CanX-5 mission currently under development at The University of Toronto Institute for Aerospace Studies Space Flight Laboratory UTIAS/SFL is a challenging formation flying technology demonstration. Its requirements of sub-metre control accuracy have yet to be realized with nanosatellites. Many large technical challenges must be addressed in order to ensure the success of the CanX-4/5 mission. This includes the development of software for an intersatellite communication system, integration and optimization of key formation flying algorithms onto the Payload On-Board Computer as well as the development of a Hardware-In-The-Loop simulator for full on-orbit mission simulations. This thesis will provide background knowledge of the Space Flight Laboratory and its activities, the CanX-4/5 mission, and nally highlight the authors contributions to overcoming each of these technical challenges and ensuring the success of the CanX-4 and CanX-5 mission.

The growth of distributed energy resources together with the incorporation of new technologies in the generation and storage of energy are imposing new control and operational strategies. Due to its storage capability and that it is considered to be clean energy; fuel cell (FC) is one of the most promissory technologies as a stationary energy source in micro grids and also in transportation applications. Therefore, two main issues are addressed in this work; the conception, design, and setup of a fully instrumented test bench for proton exchange membrane (PEM) FC stacks and the design and experimental test of a new dynamic energy-exchange control strategy for multi source and multi load systems. To define the test bench instrument requirements, in the first part a complete dynamic model review is given. In the next section, relevant information regarding the setup of the FC test bench design and implementation is included, i.e., specification criteria of the instruments and acquisition and data display system. Some experimental results are performed in order to demonstrate the potentialities of the setup. In the following chapter, a new dynamic energy exchange control strategy (DSER) is introduced and tested in a two port system via simulation and experimentation. In order to establish a comparison and integrate the DSER in a FC application, in the fifth chapter a three port system - including a static model of FC - and two different control approaches, are tested via simulation. The thesis is closed with some concluding remarks and some potential research topics generated from this work.

This thesis consists of three articles treating topics in the theory of algebraic stacks. The first two papers deal with motivic invariants. In the first, we show that the class of the classifying stack BPGLn is the inverse of the class of PGLn in the Grothendieck ring of stacks for n ≤ 3. This shows that the multiplicativity relation holds for the universal torsors, although it is known not to hold for torsors ingeneral for the groups PGL2 and PGL3. In the second paper, we introduce an exponential function which can be viewed as a generalisation of Kapranov's motivic zeta function. We use this to derive a binomial theorem for a power operation defined on the Grothendieck ring of varieties. As an application, we give an explicit expression for the motivic class of a universal quasi-split torus, which generalises a result by Rökaeus. The last paper treats destackification. We give an algorithm for removing stackiness from smooth, tame stacks with abelian stabilisers by repeatedly applying stacky blow-ups. As applications, we indicate how the result can be used for destackifying general Deligne–Mumford stacks in characteristic zero, and to obtain a weak factorisation theorem for such stacks. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 1: Manuscript. Paper 2: Manuscript. Paper 3: Manuscript.</p>

Airflow into, out of, and within buildings is fundamental to their design and operation as it can affect occupant health and comfort, building durability, and energy consumption. This thesis works to develop the understanding of airflow patterns and pressure regimes in high-rise multi-unit residential buildings which are both unique and complex due to the combination of their height, typical inclusion of operable windows, and compartmentalized layout. Specific attention is directed towards the performance of corridor pressurization based ventilation systems which are used pervasively within industry to ventilate and control contaminant transfer in these buildings. Airflow is caused by pressure differences which for buildings are created by the driving forces of wind, stack effect, and mechanical ventilation systems. These airflows are resisted by the air permeance (i.e. airtightness) of building elements including the exterior enclosure and interior compartmentalizing elements. Using an experimental program at a case study building, this thesis assesses the interaction of these driving forces of airflow with the physical building to create the airflow patterns for a typical high-rise multi-unit residential building. Perflourocarbon tracer (PFT) testing was performed to measure in-service airflows into and out of the suites. This testing found that the air change rates of upper suites are significantly higher than that of lower suites and that most suites receive small fractions of modern ventilation rates or are over ventilated. Airflow measurements of the supply of ventilation air to each corridor indicate that these low flow rates are in part due to leakage of air from the supply duct. The PFT testing also found that significant airflow occurred from the parking garage below the building into the occupied building spaces indicating significant potential for transfer of harmful air contaminants. The air permeance of the exterior enclosure and interior compartmentalizing elements were measured using neutralized fan pressurization and depressurization techniques and found to be within typical ranges. In particular this testing found that only 20% of the flow paths out of the corridor were to the adjacent suites through the suite entrance doors and that flows to the elevator shaft and stairwells could create a significant inefficiency in the ventilation system. A long-term monitoring program was implemented at the case study building primarily to monitor exterior environmental conditions including wind and exterior temperature and to correlate these with measured pressure differences. A strong correlation was found between building pressure and exterior temperature. Nearly 70% of the theoretical stack effect pressure was measured to act across the corridor to suite pressure boundary which creates a significant pressure differences to be overcome by the ventilation system, likely contributing to the uneven distribution of ventilation rates. Both wind and stack effect pressures were found to often be of similar or greater magnitude than mechanically induced pressure differences and thus can overwhelm the ventilation system. Overall, the corridor pressurization based ventilation system at the case study building does not effectively or efficiently ventilate the building and also does not provide sufficient control of air contaminants. As the case study building was found to be relatively representative of a typical multi-unit residential building, the findings from this building can be extended to many other buildings. Effective ventilation and airflow control in multi-unit residential buildings likely requires suite compartmentalization and direct supply of ventilation via ducted or in-suite systems.

Media channels play an important role in the flow, construction, and curation of knowledge in software development. Understanding how developers use media channels is key to improving developer practices and supporting channel evolution. In this thesis, I investigate the way developers use media channels to curate knowledge within the R software development community. By applying a case study methodology consisting of mining archival data and survey methods, I investigate the R community on Stack Overflow and the R-help mailing list, using a qualitative approach. The findings reveal that Stack Overflow and mailing lists foster knowledge co-construction differently---crowd-sourced and participatory respectively. Furthermore, developers use actively both channels to optimize knowledge exchange and curation. My thesis contributes to the understanding of knowledge curation by developer communities, and describes a model for a systematic comparison of two or more media channels, within a community of practice. This model allows knowledge categorization and can be used in future studies to explore knowledge flow within multiple media channels. Moreover, based on my observations in conjunction with the survey data analysis, I extracted a set of recommendations to assist practitioners in the use of multiple Question and Answer (Q&A) channels. / Graduate

Atualmente, pode-se observar que a Lei de Moore vem estagnando. A freqüência de operação já não cresce da mesma forma, e a potência consumida aumenta drasticamente em processadores de propósito geral. Ao mesmo tempo, sistemas embarcados vêm se tornando cada vez mais heterogêneos, caracterizados por uma grande quantidade de modelos computacionais diferentes, sendo executados em um mesmo dispositivo. Desta maneira, como novas tecnologias que irão substituir totalmente ou parcialmente o silício estão surgindo, novas soluções arquiteturais são necessárias. Apesar de sistemas reconfiguráveis já terem demonstrado serem candidatos em potencial para os problemas supracitados, ganhos significativos de desempenho são alcançados apenas em programas que manipulam dados massivamente, não representando a realidade dos sistemas atuais. Ademais, o seu uso em alta escala ainda está limitado à utilização de ferramentas ou compiladores que, claramente, não mantêm a compatibilidade de software e a reutilização do código binário já existente. Baseando-se nestes fatos, a presente tese propõe uma nova técnica para, utilizando um sistema reconfigurável, otimizar tanto programas orientados a dados como aqueles orientados a controle, sem a necessidade de modificação do código fonte ou binário. Para isto, um algoritmo de Tradução Binária, que trabalha em paralelo ao processador, foi desenvolvido. O mecanismo proposto é responsável pela transformação de seqüências de instruções, em tempo de execução, para serem executadas em uma unidade funcional reconfigurável de granularidade grossa, suportando execução especulativa. Desta maneira, é possível aproveitar as vantagens do uso da lógica combinacional para aumentar o desempenho e reduzir o gasto de energia, mantendo a compatibilidade binária em um processo totalmente transparente. Três diferentes estudos de caso foram feitos: os processadores Java e MIPS R3000 – representando o campo de sistemas embarcados – e o conjunto de ferramentas Simplescalar, que simula um processador superescalar baseado no MIPS R10000 – representando o mercado de processadores de propósito geral. / As Moore’s law is losing steam, one already sees the phenomenon of clock frequency reduction caused by the excessive power dissipation in general purpose processors. At the same time, embedded systems are getting more heterogeneous, characterized by a high diversity of computational models coexisting in a single device. Therefore, as innovative technologies that will completely or partially replace silicon are arising, new architectural alternatives are necessary. Although reconfigurable computing has already shown to be a potential solution for such problems, significant speedups are achieved just in very specific dataflow oriented software, not representing the reality of nowadays systems. Moreover, its wide spread use is still withheld by the need of special tools and compilers, which clearly preclude software portability and reuse of legacy code. Based on all these facts, this thesis presents a new technique using reconfigurable systems to optimize both control and dataflow oriented software without the need of any modification in the source or binary codes. For that, a Binary Translation algorithm has been developed, which works in parallel to the processor. The proposed mechanism is responsible for transforming sequences of instructions at runtime to be executed on a dynamic coarse-grain reconfigurable array, supporting speculative execution. This way, it is possible to take advantage of using pure combinational logic to speed up the execution, maintaining full binary compatibility in a totally transparent process. Three different case studies were evaluated: a Java Processor and a MIPS R3000 – representing the embedded systems field – and the Simplescalar Toolset, a widely used toolset that simulates a superscalar architecture based on the MIPS R10000 processor – representing the general-purpose market.

Les procédés de dépôt de couches minces optiques par voie physique ou par voie sol-gel présentent par nature des limitations pour la réalisation de revêtements épais (>1 µm) et ont alors recours à des empilements multicouches pour la préparation de miroirs diélectriques ou de polariseurs. C'est pour ces raisons qu'il est intéressant d'étudier les conditions permettant d'augmenter l'épaisseur critique des films sol-gel notamment. Après avoir étudié la capacité d'empilements des couches colloïdales, trois principaux paramètres ont été identifiés permettant d'augmenter l'épaisseur critique d'empilements monomatériaux et multimatériaux. Ces paramètres sont : l'épaisseur déposée,les interactions chimiques entre les particules et le temps de séchage du film. Ils influencent la microstructure des empilements et par conséquent les propriétés optiques et mécaniques. En contrôlant tous ces paramètres, nous avons montré qu'il est possible de préparer des empilements colloïdaux de fortes épaisseurs ouvrent la voie à la préparation sol-gel de miroirs de hautes performances et/ou de polariseurs. En outre, un développement spécifique de méthodes de caractérisations optiques et mécaniques a été nécessaire pour l'étude de ces films sol-gel, à la fois minces et fragiles. / Main optical deposition processes, physical vapor deposition or sol-gel, exhibit difficulties of achieving thick coatings (>1 µm) and to build multilayer stacks (dielectric mirrors, polarizers). For these reasons, we have studied the conditions to enable a significative increase of deposited sol-gel films thickness. Three main parameters have been evidenced enabling the control of the stacking ability : single layer deposited thickness, chemical interactions beetween nanoparticles and coating drying time. We have shown that these parameters depend on the sol composition and on deposition conditions (process) and that the microstructure of single material stacking is influenced. Optical and mechanical properties of sol-gel films have been studied and optimized regarding these different material and process parameters. For this reason, optical and mechanical characterization techniques have been specifically developed and can now be used for fragile and thin film characterization. In controlling all these parameters, it is now possible to prepare multilayer colloidal stack with high thicknesses enabling the fabrication of high-performance mirrors and polarizers.