A Thesis submitted to The University of Arizona College of Medicine - Phoenix in partial fulfillment of the requirements for the Degree of Doctor of Medicine. / BACKGROUND & SIGNIFICANCE Hypoplastic left heart syndrome (HLHS) is a congenital condition that involves hypoplasia or atresia of left heart structures. Treatment requires three separate interventions, and the “hybrid” procedure is a less invasive alternative to the initial open-heart operation. This approach has become favorable for certain patients in recent years, but there is a need to better understand the outcomes and the factors that influence the outcomes for hybrid Stage 1 palliation of HLHS.

In this paper, the benefits and advantages of combining advanced embedded processing capabilities with an FPGA based approach within a Data Acquisition Unit (DAU) are discussed. The paper begins with a discussion of some of the services and functionality that such a system enables. Basic features such as system discovery, verification, configuration and upgrade are discussed in addition to other value added services such as continuous built in test (CBIT) and embedded real-time parameter quick-look. Finally, the paper discusses some advanced services that could be deployed to these systems such as emerging communication protocols, multimedia connectivity and discovery, and advanced Machine Learning based systems diagnostics.

Wireless sensor networks (WSN) have been largely used in various applications due to its ease of deployment and scalability. The throughput of such networks, however, suffers from high bit error rates mainly because of medium characteristics. Maximizing bandwidth utilization while maintaining low frame error rate has been an interesting problem. Frame fragmentation into small blocks with dedicated error detection codes per block can reduce the unnecessary retransmission of the correctly received blocks. The optimal block size, however, varies based on the wireless channel conditions. In addition, blocks within a frame can have different optimal sizes based on the variations on interference patterns. This thesis studies two dynamic partial packet recovery approaches experimentally over several interference intensities with various transmission-power levels. It also proposes a dynamic data link layer protocol: Hybrid Seda (H-Seda). H-Seda effectively addresses the challenges associated with dynamic partitioning of blocks while taking the observed error patterns into consideration. The design of H-Seda is discussed in details and compared to other previous approaches, namely Seda+ and Seda. The implementation of H-Seda shows substantial enhancements over fixed-size partial packet recovery protocols, achieving up to 2.5x improvement in throughput when the channel condition is noisy, while delay experienced decreases to only 14 % of the delay observed in Seda. On average, it shows 35% gain in goodput across all channel conditions used in our experiments. This significant improvement is due to the selective nature of H-Seda which minimizes retransmission overhead by selecting the appropriate number of blocks in each data frame. Additionally, H-Seda successfully reduces block overhead by 50% through removing block number field reaching to better performance when channel conditions are identical.

In today’s extremely competitive marketplace, firms are facing the need to meet or exceed increasing customer expectations while cutting costs to stay competitive in a global market. To develop competitive advantage in this business climate, companies must make informed decisions regarding their supply chain. In recent years, supply chain networks have received increasing attention among companies. The decision makers confront the network design problem in different situations. In order to make decisions, especially in strategic supply chain management, decision makers must have a holistic view of all the components. Supply chain network design, particular facility location problems, is one of the most complex strategic decision problems in supply chain management The aim of this dissertation is to make an inquiry about the facility location problems and related issues in supply chain and logistics management, and the use of modelling approaches to solve these problems. The methodology is to construct a review protocol by forming a review panel, and developing a detailed search strategy with clear inclusion and exclusion criteria. In addition, the measurement for evaluating the quality of studies is presented with a strategy for extracting data and synthesising the methodologies. The search results show the background of the facility location problems, the importance and the basic questions of these problems. The taxonomy of facility location problems with eighteen factors is presented. The basic static and deterministic problems in facility location including the covering, centre, median and fixed charge problems are discussed. Also, the extension of facility location problems comprises of location-allocation, multi-objective, hierarchical, hub, undesirable and competitive problems. In terms of uncertainty, dynamic, stochastic and robust facility location problems are presented. Finally, strengths and weaknesses of different modelling approaches are discussed; importantly, gaps from the review process are indentified. Recommendations of future research are described; and the facility location problem to be addressed by the proposed research is shown. In addition, contributions of the proposed facility location problem are illustrated.

The brain microcirculation plays a key role in cerebral physiology and neuronal activation. In the case of degenerative diseases such as Alzheimer’s, severe deterioration of the microvascular networks (e.g. vascular occlusions) limit blood flow, thus oxygen and nutrients supply, to the cortex, eventually resulting in neurons death. In addition to functional neuroimaging, modelling is a valuable tool to investigate the impact of structural variations of the microvasculature on blood flow and mass transfers. In the brain microcirculation, the capillary bed contains the smallest vessels (1-10 μm in diameter) and presents a mesh-like structure embedded in the cerebral tissue. This is the main place of molecular exchange between blood and neurons. The capillary bed is fed and drained by larger arteriolar and venular tree-like vessels (10-100 μm in diameter). For the last decades, standard network approaches have significantly advanced our understanding of blood flow, mass transport and regulation mechanisms in the human brain microcirculation. By averaging flow equations over the vascular cross-sections, such approaches yield a one-dimensional model that involves much fewer variables compared to a full three-dimensional resolution of the flow. However, because of the high density of capillaries, such approaches are still computationally limited to relatively small volumes (<100 mm3). This constraint prevents applications at clinically relevant scales, since standard imaging techniques only yield much larger volumes (∼100 cm3), with a resolution of 1-10 mm3. To get around this computational cost, we present a hybrid approach for blood flow modelling where the capillaries are replaced by a continuous medium. This substitution makes sense since the capillary bed is dense and space-filling over a cut-off length of ∼50 μm. In this continuum, blood flow is characterized by effective properties (e.g. permeability) at the scale of a much larger representative volume. Furthermore, the domain is discretized on a coarse grid using the finite volume method, inducing an important computational gain. The arteriolar and venular trees cannot be homogenized because of their quasi-fractal structure, thus the network approach is used to model blood flow in the larger vessels. The main difficulty of the hybrid approach is to develop a proper coupling model at the points where arteriolar or venular vessels are connected to the continuum. Indeed, high pressure gradients build up at capillary-scale in the vicinity of the coupling points, and must be properly described at the continuum-scale. Such multiscale coupling has never been discussed in the context of brain microcirculation. Taking inspiration from the Peaceman “well model” developed for petroleum engineering, our coupling model relies on to use analytical solutions of the pressure field in the neighbourhood of the coupling points. The resulting equations yield a single linear system to solve for both the network part and the continuum (strong coupling). The accuracy of the hybrid model is evaluated by comparison with a classical network approach, for both very simple synthetic architectures involving no more than two couplings, and more complex ones, with anatomical arteriolar and venular trees displaying a large number of couplings. We show that the present approach is very accurate, since relative pressure errors are lower than 6 %. This lays the goundwork for introducing additional levels of complexity in the future (e.g. non uniform hematocrit). In the perspective of large-scale simulations and extension to mass transport, the hybrid approach has been implemented in a C++ code designed for High Performance Computing. It has been fully parallelized using Message Passing Interface standards and specialized libraries (e.g. PETSc). Since the present work is part of a larger project involving several collaborators, special care has been taken in developing efficient coding strategies.

The solution of generation scheduling (GS) problems involves the determination of the unit commitment (UC) and economic dispatch (ED) for each generator in a power system at each time interval in the scheduling period. The solution procedure requires the simultaneous consideration of these two decisions. In recent years researchers have focused much attention on new solution techniques to GS. This paper proposes the application of a variety of genetic algorithm (GA) based approaches and investigates how these techniques may be improved in order to more quickly obtain the optimum or near optimum solution for the GS problem. The results obtained show that the GA-based hybrid approach offers an effective alternative for solving realistic GS problems within a realistic timeframe.

Avec l’usage élargi de la CAAO, ces outils ont été largement utilisés dans le processus de conception architecturale. En dépit des fonctionnalités avancées offertes par les systèmes de CAAO, l'utilisation de la CAAO est principalement concentrée dans les étapes de production, comme un support graphique pour le dessin, la modélisation, le rendu et la simulation. Par conséquent, il est raisonnable de considérer que la situation actuelle relative à l’usage de la CAAO dans la profession d'architecte appelle à de nouvelles améliorations. En d'autres termes, nous devons trouver un moyen de mieux intégrer la technologie et les outils de CAAO dans le processus de conception architecturale, qui est notre question de recherche. Nous avons besoin de savoir comment la CAAO pourrait être utilisée pour améliorer la capacité de conception de l'architecte. Il ressort des discussions et des recherches menées pour cette étude que nous voulons un soutien de la technologie pour nous aider à mieux concevoir et non pas que la technologie conçoive à notre place. Nous aimerions avoir un système de CAAO qui pourrait nous servir d’assistant à la conception. En étudiant la situation de l'intégration des outils de CAAO dans les pratiques actuelles de conception des architectes et en examinant les approches utilisées dans les premières tentatives de développement d’un outil de CAAO intégré au processus de conception, on peut conclure que l'approche exploratoire et heuristique serait une meilleure approche qui pourrait être adaptée pour développer un système CAAO en soutien au travail de l’architecte. De plus, une étude plus approfondie a démontré que les deux sous- approches des approches exploratoires et heuristiques (approches basées sur les cas et les contraintes), sont applicables, mais aucune d'elles n'est suffisante. Par conséquent, l’approche hybride qui prend en compte les avantages de chacune des deux sous- approches précitées serait la plus applicable. Elle nous permettrait de développer un outil CAAD qui pourrait vraiment être intégré dans le processus de conception architecturale. Cette conclusion a été vérifiée par une étude complémentaire basée sur des entrevues. / The CAAD tools have been widely adopted in the architectural design process with the popular utilization of CAAD. In spite of the advanced features that have been designed for the CAAD systems, the utilization of CAAD is mainly concentrated on the production stage of design, as a graphic medium for drawing, modeling, rendering and simulation. Therefore, it is reasonable to deem that the current situation of CAAD tools involvement in the architectural profession is calling for further improvement. In other words, we need to find a way to better integrate the CAAD tools/technology into the architectural conceptual design stage, which is our research question. We need to find out how CAAD could be utilized to improve the architect’s design ability during the conceptual design. The discussion and research conducted for this study lead to the assessment that we want technology to help us design better, but not to design for us. We would like to have a CAAD system that could help us as a design assistant. By studying the current situation of the integration of CAAD tools into architects’ design practice and reviewing the approaches that have been employed to create a CAAD tool that could be better integrated into the design process, we reach the decision that the exploring & heuristic approach would be a preferred approach that could be adopted to further develop a more feasible CAAD system. In addition, within the two sub-approaches of the Exploring & Heuristic Approaches (case-based approach and constraint approach), further study has proved that both of them are applicable approaches, but neither of them could sufficiently serve as the sole approach for this purpose. Therefore, a hybrid approach that takes advantage of both approaches would be the most applicable one because it can help us develop a CAAD tool that could be really integrated into the conceptual architectural design procedure.

Living in an information-overloading age, the original information searching mechanisms are ineffective and impractical. As the e-commerce is more and more popular, using information technology to discover the latent demand of customers becomes an important issue. Hence, a variety of recommendation techniques have been proposed and many of them have been implemented in real systems, mostly in online stores. Among the techniques, the content-based and collaborative filtering approaches are the ones broadly adopted and proved to be successful. Recently, social network-based recommendation approach has been proposed that takes into account the similarities of items with respect to their social closeness. The social network-based approach performs better than content-based approach in some scenarios and it can also avoid recommending articles that have high content similarity to a user¡¦s favorite articles but low quality. Therefore, we propose three hybrid approaches, Switching, Proportional, and Fusion that combine content-based and social network-based approaches in order to achieve a better performance. Our experimental result shows that even though the proposed approaches have pros and cons under different scenarios, in general they achieve better performance than individual approaches. Besides, we generate some synthetic articles that have close content similarities to articles in our collection to evaluate the fidelity of each approach. The experimental results show that approaches incorporating social network information have lower chance to recommend these faked articles.

Avec l’usage élargi de la CAAO, ces outils ont été largement utilisés dans le processus de conception architecturale. En dépit des fonctionnalités avancées offertes par les systèmes de CAAO, l'utilisation de la CAAO est principalement concentrée dans les étapes de production, comme un support graphique pour le dessin, la modélisation, le rendu et la simulation. Par conséquent, il est raisonnable de considérer que la situation actuelle relative à l’usage de la CAAO dans la profession d'architecte appelle à de nouvelles améliorations. En d'autres termes, nous devons trouver un moyen de mieux intégrer la technologie et les outils de CAAO dans le processus de conception architecturale, qui est notre question de recherche. Nous avons besoin de savoir comment la CAAO pourrait être utilisée pour améliorer la capacité de conception de l'architecte. Il ressort des discussions et des recherches menées pour cette étude que nous voulons un soutien de la technologie pour nous aider à mieux concevoir et non pas que la technologie conçoive à notre place. Nous aimerions avoir un système de CAAO qui pourrait nous servir d’assistant à la conception. En étudiant la situation de l'intégration des outils de CAAO dans les pratiques actuelles de conception des architectes et en examinant les approches utilisées dans les premières tentatives de développement d’un outil de CAAO intégré au processus de conception, on peut conclure que l'approche exploratoire et heuristique serait une meilleure approche qui pourrait être adaptée pour développer un système CAAO en soutien au travail de l’architecte. De plus, une étude plus approfondie a démontré que les deux sous- approches des approches exploratoires et heuristiques (approches basées sur les cas et les contraintes), sont applicables, mais aucune d'elles n'est suffisante. Par conséquent, l’approche hybride qui prend en compte les avantages de chacune des deux sous- approches précitées serait la plus applicable. Elle nous permettrait de développer un outil CAAD qui pourrait vraiment être intégré dans le processus de conception architecturale. Cette conclusion a été vérifiée par une étude complémentaire basée sur des entrevues. / The CAAD tools have been widely adopted in the architectural design process with the popular utilization of CAAD. In spite of the advanced features that have been designed for the CAAD systems, the utilization of CAAD is mainly concentrated on the production stage of design, as a graphic medium for drawing, modeling, rendering and simulation. Therefore, it is reasonable to deem that the current situation of CAAD tools involvement in the architectural profession is calling for further improvement. In other words, we need to find a way to better integrate the CAAD tools/technology into the architectural conceptual design stage, which is our research question. We need to find out how CAAD could be utilized to improve the architect’s design ability during the conceptual design. The discussion and research conducted for this study lead to the assessment that we want technology to help us design better, but not to design for us. We would like to have a CAAD system that could help us as a design assistant. By studying the current situation of the integration of CAAD tools into architects’ design practice and reviewing the approaches that have been employed to create a CAAD tool that could be better integrated into the design process, we reach the decision that the exploring & heuristic approach would be a preferred approach that could be adopted to further develop a more feasible CAAD system. In addition, within the two sub-approaches of the Exploring & Heuristic Approaches (case-based approach and constraint approach), further study has proved that both of them are applicable approaches, but neither of them could sufficiently serve as the sole approach for this purpose. Therefore, a hybrid approach that takes advantage of both approaches would be the most applicable one because it can help us develop a CAAD tool that could be really integrated into the conceptual architectural design procedure.

An efficient simulation technique for calculating the current distribution in a Vertical Cavity Surface Emitting Laser (VCSEL) is proposed and implemented. The technique consists of a hybrid 1D/3D approach to the problem. The 3D aspect of simulation is essential for devices like a photonic crystal VCSEL where the existing 2D simulation techniques are inadequate. The modular approach of the technique is advantageous, as it provides exibility in dealing with device simulations of varying complexity. It also provides a relatively short simulation time, beneficial for exploring a large design parameter space. The box integration technique is used for discretizing the equations and sparse matrix methods are used in solving the matrices. Simulation results and comparisons are provided for various aspects and modules of the simulator. The results for a few sample simulations indicate that the analysis has reasonable agreement with experimental results. The simulation error can be reduced using more accurate models for the active region of the laser.