The development of a quantum computer presents one of the greatest challenges in science and engineering to date. The promise of more ecient computing based on entangled quantum states and the superposition principle has led to a worldwide explosion of interest in the elds of quantum information and computation. Decoherence is one of the main problems that gives rise to dierent errors in the quantum system. However, the discovery of quantum error correction and the establishment of the accuracy threshold theorem provide us comprehensive tools to build a quantum computer. This thesis contributes to this eort by investigating a particular class of quantum error correcting codes, called Decoherence free subsystems. The passive approach to error correction taken by these encodings provides an ecient means of protection for symmetrically coupled system-bath interactions. Here I will present methods for determining the subsystem-preserving evolutions for noiseless subsystem encodings and more importantly implementing a Universal quantum computing over three-quantum dots.

Orientador: Caio Cesar Randi Ferraz / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-16T16:29:46Z (GMT). No. of bitstreams: 1 Brum_JoelsonRodrigues_M.pdf: 5614264 bytes, checksum: b37145c988831b42c354756754fe55e5 (MD5) Previous issue date: 2010 / Resumo: Este estudo teve como objetivo avaliar a influência de diferentes substâncias químicas auxiliares usadas durante o preparo químico-mecânico do canal radicular sobre a qualidade de selamento coronário dos materiais obturadores endodônticos. Oitenta raízes de pré-molares inferiores humanos foram seccionadas, instrumentadas e divididas aleatoriamente em 12 grupos experimentais em função do protocolo de irrigação e do material obturador utilizado (G1- sol. salina / guta-percha + Endofill (GP+E); G2- CLX (clorexidina) gel 2% / GP+E; G3- CLX gel 2% + EDTA (ác. Etileno DiaminoTetracético) 17% / GP+E; G4- EDTA 17% / GP+E; G5- NaOCl (hipoclorito de sódio) 5,25% + EDTA 17% / GP+E; G6- NaOCl 5,25% / GP+E; G7- sol. salina / SRE (SE) (Sistema Resilon Epiphany "self-etching"); G8- CLX gel 2% / SRE (SE); G9- CLX gel 2% + EDTA 17% / SRE (SE); G10- EDTA 17% / SRE (SE); G11- NaOCl 5,25% + EDTA 17% / SRE (SE); G12- NaOCl 5,25% / SRE (SE)). Todos os espécimes foram obturados pela técnica da condensação lateral. As raízes foram armazenadas em estufa à 37ºC e 100% de umidade por 7 dias. Após este período, a microinfiltração coronária foi avaliada por meio da metodologia de filtração de fluido, observando-se a movimentação da microbolha pelo capilar de vidro, sugerindo possíveis falhas na obturação endodôntica. Os dados foram submetidos à avaliação estatística pelo método não paramétrico de Kruskal-Wallis onde os resultados mostraram que todos os grupos apresentaram microinfiltração coronária, que não houve diferença estatística na qualidade do selamento coronário promovido pelos materiais obturadores GP+E e SRE (SE) independente dos protocolos de irrigação utilizados e que o SRE (SE) apresentou selamento coronário mais efetivo com protocolo de irrigação CLX gel 2% + EDTA 17% comparado aos grupos irrigados exclusivamente com NaOCl 5,25% e o grupo obturado com GP+E após protocolo de irrigação CLX gel 2% / Abstract: The aim of this study was to evaluate the influence of different auxiliary chemicals substances used during root canal preparation on the coronal sealing by endodontic distinct obturation material. Eighty roots from human mandibular premolars were sectioned, prepared and randomly divided into 12 experimental groups according to the auxiliary chemical substance and the obturation material used (G1- normal saline / Gutta Percha+Endofill; G2- CLX gel 2% / GP+E; G3- CLX gel 2% + EDTA 17% / GP+E; G4- EDTA 17% / GP+E; G5- NaOCl 5,25% / GP+E; G6- NaOCl 5,25% + EDTA17% / GP+E; G7- normal saline / SRE (SE) (Resilon Epiphany System "self-etching"); G8- CLX gel 2% / SRE (SE); G9- CLX gel 2% + EDTA 17% / SRE (SE); G10- EDTA 17% / SRE (SE); G11- NaOCl 5,25% + EDTA17% / SRE (SE); G12- NaOCl 5,25% / SRE (SE)). All specimens were obturated by the lateral condensation technique. The roots were stored at 37°C and 100% humidity conditions for 7 days. Following, the coronal microleakage was evaluated by the fluid filtration methodology, measuring the movement of a bubble in the capillary glass (µL/min) suggesting possible voids in the endodontic filling. Data were statistically analyzed by the Kruskal-Wallis test. The results showed no statistical difference between the sealers (p>0.05) regardless the chemical irrigating solutions used, and was observed that CLX gel 2% + EDTA 17% / SRE (SE), presented better coronary sealing than all groups that used NaOCl 5,25% alone and the group filled with GP after the irrigation using CLX gel 2% / Mestrado / Endodontia / Mestre em Clínica Odontológica

El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / Introduction: Coronal microleakage caused by temporary restorative materials is viewed as one of the reasons for endodontic failure. Efforts have been made in recent years to create a temporary restorative material capable of preventing that problem. Objective: Compare in vitro coronal microleakage of an "experimental cement" and four temporary restorative materials used in endodontics. Methods: Class I cavities were made in 90 premolar teeth divided into 10 groups (n= 9) and evaluated at two time periods (1 and 2 weeks). The "experimental cement" was prepared and then coronal sealing of the teeth was performed with the experimental Cement, F (VOCO), Eugenato (MOYCO), Ketac™ Molar Easymix 3M (ESPE) and Coltosol® F. The pieces were submerged in India ink (Pelikan)for 1 and 2 weeks. Microleakage was evaluated on the interface dentin wall / temporary restoration using a stereo microscope (Leica Microsystems LAS EZ version 2.0.0). Measurement was made in millimeters using the software LAS EZ version 2.0.0. Results: Statistically significant differences were found (p< 0.05) when comparing coronal microleakage in the five temporary restorative materials according to exposure time in ink (1 and 2 weeks). Conclusions: The experimental cement had less microleakage than Coltosol® F and Ketac™ Molar EasyMix 3M (ESPE). However, none of the four materials was capable of completely preventing microleakage. / Revisión por pares

This thesis uses a model-based approach to finding optimal positions of flow datasensors in a water distribution network (WDN). Flow data sensors can be used toidentify and localize leaks in a network that lead to significant losses of both water and energy. A simple hydraulic model of a WDN was constructed as well as a graph theoreticdescription of the network. A framework for describing the information gained by aspecific sensor position was developed and used to formulate the sensor placement asan optimization problem.Two algorithms were constructed for finding the optimal placements under differentassumptions of the network. Three smaller networks of different complexity wereconstructed and on which the two algorithms were tested.The results show that a model-based approach indeed can be used to find optimalsensor placement under different assumptions of the system at hand and that theframework can be used not only for placement, but also for localization of leakspresent in the network.

Leaks in pipe networks cause significant problems for utilities and water users in terms of lost revenue and interrupted service. In many cities the leakage is as high as forty percent. A water audit is carried out to assess system-wide leakage. However, to detect leakage at the level of a pipeline, a physical measurement technique is generally employed. For large cities the distribution piping length amounts to a few thousand miles. Therefore, the physical measurements can become tedious and expensive. In this thesis it is assumed that a spatial distribution of leakage can be estimated at nodes based on a water audit bookkeeping scheme. A mathematical formulation consisting of continuity, energy (headloss), pressure-dependent demands and/or leakage, and flow direction preservation equations are utilized to distribute demand flows and leakage among pipes. The leakage is attributed to the formation of corrosion holes. Based upon the extent of corrosion, the leakage flow arriving at a particular node is apportioned among all pipes that are converging at that node. Therefore, the formulation presented in this thesis captures the two essential elements behind leakage, namely, pressure driven flow distribution and the vulnerability of pipes to corrosion. The proposed formulation allows utilities to be more proactive in identifying leakage prone districts within the water distribution system. An understanding of the pressure-dependent leakage in the system is helpful when performing a water audit and in developing strategies for leak repair programs. Restoring the full capacity of the water distribution system will greatly increase the reliability of the system, thereby benefiting local utilities and water users. / Master of Science

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A large-scale moving end-wall system has been designed and built at the Aerospace and Ocean Engineering Department of Virginia Tech. This system forms part of a low-speed linear compressor cascade wind tunnel, where it is used to simulate the effects of the relative motion between the blade tips and casing upon the flow. Detailed 4-sensor hot wire measurements were made at various locations downstream the cascade. The results are presented in term of mean flow field and turbulence flow field. In order to reveal the effects of moving end wall, the results also compared with the results obtained with stationary end wall. / Master of Science

Side-channel leakage, caused by imperfect implementation of cryptographic algorithms in hardware, has become a serious security threat for connected devices that generate and process sensitive data. This side-channel leakage can divulge secret information in the form of power consumption or electromagnetic emissions. The side-channel leakage of a crytographic device is commonly assessed after tape-out on a physical prototype. This thesis presents a methodology called Gate-level Leakage Assessment (GLA), which evaluates the power-based side-channel leakage of an integrated circuit at design time. By combining side-channel leakage assessment with power simulations on the gate-level netlist, GLA is able to pinpoint the leakiest cells in the netlist in addition to assessing the overall side-channel vulnerability to side-channel leakage. As the power traces obtained from power simulations are noiseless, GLA is able to precisely locate the sources of side-channel leakage with fewer measurements than on a physical prototype. The thesis applies the methodology on the design of a encryption co-processor to analyze sources of side-channel leakage. Once the gate-level leakage sources are identified, this thesis presents a logic level replacement strategy for the leakage sources that can thwart side-channel leakage. The countermeasures presented selectively replaces gate-level cells with a secure logic style effectively removing the side-channel leakage with minimal impact in area. The assessment methodology along with the countermeasures demonstrated is a turnkey solution for IP module designers and is also applicable to larger system level designs. / Master of Science / Consider how a lie detector machine works. It looks for subtle changes in a person’s pulse to tell if the person is telling the truth. This unintentional divulgence of secret information is called a side-channel leakage. Integrated circuits reveal secret information in a similar way through their power consumption. This is caused by the transistors, used to build these integrated circuits, switching in concert with the secret data being processed by the integrated circuit. Typically, integrated circuits are evaluated for side-channel leakage only after they have been manufactured into a physical prototype. If the integrated circuit is found vulnerable it is too expensive to manufacture the prototype again with an updated design. This thesis presents a methodology, Gate-level Leakage Assessment (GLA) to evaluate integrated circuits for side-channel leakage during their design process even before they are manufactured. This methodology uses simulations to identify the specific transistors in the design that cause side-channel leakage. Moreover, this thesis presents a technique to selectively replace these problematic transistors in the design with an implementation that thwarts side channel leakage.