No description available.

The increasing waiting times to access healthcare services are a major concern for pa-tients in hospitals. Due to the unpredictability of health issues, hospitals and clinical ser-vices are provided to patients even without prescheduled medical appointments. Unex-pected and random patient arrivals can result in high waiting times. Waiting occurs most-ly because of insufficient resources available compared to demanding service delivery requirements at a given time. Thus, appropriate management of resource scheduling over time can help reduce patient wait times. So far, simulation has mostly been used as a support for strategic decision making in healthcare environments. We are proposing a complementary approach, namely, real-time simulation, to support operational decision making rather than long-term strategic decision making. Real-time simulation is a technique used to get a timely prediction of the system status in a near future (e.g., a few hours). Hospitals can benefit from the capa-bilities of real-time simulations by predicting upcoming bottleneck occurrences in patient care processes and make effective decisions in the present time to avoid undesirable out-comes in the near future. This research presents real-time simulation capabilities for short-term operational decision making of patient care processes in hospitals and the possible ways to run alter-native scenarios and evaluate their results to come up with the most effective solution considering various factors. This thesis also provides tool support based on a leading simulation environment, namely Arena. The tool-supported methodology is evaluated through a realistic cardiac care process in an Ontario community hospital, with encourag-ing results.

Les travaux de thèse concernent le développement d’une plateforme d’émulation temps réel destinée aux études théoriques et expérimentales des systèmes hybrides éolien- hydrolien. Diverses architectures de couplages énergétiques sont traitées sur la base des similitudes fonctionnelles des deux systèmes et par des concepts d’émulation à la fois numériques et expérimentaux. La notion de simulation en temps « accéléré » a été développée. Le concept a été validé sur la plateforme expérimentale en utilisant l’évolution de la puissance moyenne délivrée par une turbine éolienne de petite puissance. Cette approche pourra permettre de réduire les temps d’observation des campagnes de mesure, d’accélérer les études sur le potentiel éolien des sites en développement. Nous avons développé également deux types de couplage du système hybride éolien-hydolien. Un couplage électrique basé sur la connexion en parallèle sur un bus continu des deux turbines. Nous avons développé un concept innovant d’un couplage électromécanique basé sur l’utilisation d’une seule génératrice asynchrone sur laquelle sont simultanément couplés les arbres de la turbine éolienne et de la turbine hydrolienne. Pour cela, un servomoteur à commande vectorielle nous a servi à émuler la turbine éolienne pendant qu’un moteur synchrone nous a servi d'émulateur de turbine hydrolienne. L’arbre de la génératrice sert de couplage mécanique entre les deux systèmes. Nous avons mis en évidence dans les expérimentations effectuées, la complémentarité des productions électriques des deux systèmes, et également le besoin de leur adjoindre un système de stockage pour palier à une baisse simultanée de deux productions d’énergie. / The thesis work concerns the development of a real-time emulation platform for theoretical and experimental studies of offshore wind and tidal power hybrid systems. Various energy coupling architectures are processed on the basis of the functional similarities of two systems and by both numerical and experimental emulation concepts. The notion of accelerated time used for real time simulation has been developed. The concept was validated on the experimental platform using the evolution of the mean power delivered by a small wind turbine. This approach can reduce the observation times of the measurement campaigns and could accelerate the studies for the wind potential of developing sites. We have also developed two types of coupling of the wind-tidal hybrid system. An electrical coupling based on the connection in parallel on a continuous bus of two turbines. We have developed an innovative concept of an electromechanical coupling based on the use of a single asynchronous generator on which the wind turbine and tidal turbine are simultaneously coupled. For this purpose, a vector-controlled servomotor was used to emulate the wind turbine while a synchronous motor was used as a tidal turbine emulator. The generator shaft is used as a mechanical coupling between the two systems. We have demonstrated in the experiments that we have developed the complementarity of the electrical productions of the two systems; we highlighted the need to add a storage system to compensate the simultaneous decrease of the two energy productions. The real time simulations results allow us to validate the feasibility of such a coupling.

The increasing waiting times to access healthcare services are a major concern for pa-tients in hospitals. Due to the unpredictability of health issues, hospitals and clinical ser-vices are provided to patients even without prescheduled medical appointments. Unex-pected and random patient arrivals can result in high waiting times. Waiting occurs most-ly because of insufficient resources available compared to demanding service delivery requirements at a given time. Thus, appropriate management of resource scheduling over time can help reduce patient wait times. So far, simulation has mostly been used as a support for strategic decision making in healthcare environments. We are proposing a complementary approach, namely, real-time simulation, to support operational decision making rather than long-term strategic decision making. Real-time simulation is a technique used to get a timely prediction of the system status in a near future (e.g., a few hours). Hospitals can benefit from the capa-bilities of real-time simulations by predicting upcoming bottleneck occurrences in patient care processes and make effective decisions in the present time to avoid undesirable out-comes in the near future. This research presents real-time simulation capabilities for short-term operational decision making of patient care processes in hospitals and the possible ways to run alter-native scenarios and evaluate their results to come up with the most effective solution considering various factors. This thesis also provides tool support based on a leading simulation environment, namely Arena. The tool-supported methodology is evaluated through a realistic cardiac care process in an Ontario community hospital, with encourag-ing results.

Comme tout processus industriel, un système photovoltaïque peut être soumis, au cours de son fonctionnement, à différents défauts et anomalies conduisant à une baisse de la performance du système et voire à son indisponibilité. Permettre de diagnostiquer finement et de faire de la détection et de localisation de défauts dans une installation PV réduit les coûts de maintenance et surtout augmente la productivité. Dans ce travail de thèse, nous nous intéressons spécifiquement à la détection et la localisation de défauts côté DC du système PV, c'est-à-dire du côté générateur PV. L'objectif de cette thèse est de proposer, en prenant le moins de mesures possibles pour respecter les contraintes économiques, un algorithme pour détecter et localiser des défauts conduisant à une baisse de production. Pour cela, le choix s'est porté sur l'analyse de la caractéristique I-V du générateur PV pour les différents modes de fonctionnement considérés. Cette analyse a conduit à utiliser la méthode d'inférence pour effectuer le diagnostic de l'installation. Cette démarche a été validée par des expérimentations sur site, des simulations temps-réel et hors temps-réel. / As every industrial process, a photovoltaic system may subject, during his operation, to various faults and abnormalities leading to a drop of its efficiency up to its unavailability. A precise diagnosis and a fault detection and isolation make it possible to reduce the maintenance costs and above all increase the yield. In this work, a focus has been made on the fault detection and isolation in the DC part of the PV system, it means of the PV array. The goal of this work is to propose, by conducting the less possible measurements to meet the economic constraints, an algorithm to detect an isolate the faults causing a drop in the array yield. To achieve this goal, the analysis of the I-V characteristic has been chosen. This analysis leads to the use of the inference method to conduct the diagnosis of the PV plant. This procedure has been validated by on site experiments, real-time simulations and non real-time simulations.

abstract: This dissertation covers three primary topics and relates them in context. High frequency transformer design, microgrid modeling and control, and converter design as it pertains to the other topics are each investigated, establishing a summary of the state-of-the-art at the intersection of the three as a baseline. The culminating work produced by the confluence of these topics is a novel modular solid-state transformer (SST) design, featuring an array of dual active bridge (DAB) converters, each of which contains an optimized high-frequency transformer, and an array of grid-forming inverters (GFI) suitable for centralized control in a microgrid environment. While no hardware was produced for this design, detailed modeling and simulation has been completed, and results are contextualized by rigorous analysis and comparison with results from published literature. The main contributions to each topic are best presented by topic area. For transformers, contributions include collation and presentation of the best-known methods of minimum loss high-frequency transformer design and analysis, descriptions of the implementation of these methods into a unified design script as well as access to an example of such a script, and the derivation and presentation of novel tools for analysis of multi-winding and multi-frequency transformers. For microgrid modeling and control, contributions include the modeling and simulation validation of the GFI and SST designs via state space modeling in a multi-scale simulation framework, as well as demonstration of stable and effective participation of these models in a centralized control scheme under phase imbalance. For converters, the SST design, analysis, and simulation are the primary contributions, though several novel derivations and analysis tools are also presented for the asymmetric half bridge and DAB. / Dissertation/Thesis / Doctoral Dissertation Electrical Engineering 2019

Background. Physically-based snow simulation is computationally expensive and not yet applicable to real-time applications. Some of the prime factors for this cost are the complex physics, the large number of particles, and the small time step required for a high-quality and stable simulation.Simplified methods, such as height maps, are used instead to emulate snow accumulation. A way of improving performance is finding ways of doing less computations. In the field of computer graphics, adaptive methods have been developed to focus computation to where it is most needed. These works will serve as inspiration for this thesis. Objectives. This thesis aims to reduce the total particle workload of an existing Discrete Element Method (DEM) application, thereby improving performance. The aim consists of the following objectives. Integrate a spatial method, thereby lessening the total number of particles through particle merging and splitting, and implement a temporal method, thereby lessening the workload by freezing certain particles in time. The performance of both these techniques will then be tested and analyzed in multiple scenarios. Methods. Spatially and temporally adaptive methods were implemented in an existing snow simulator. The methods were both measured and compared using quantitative tests in three different scenes with varying particle counts. Results. Performance tests show that both the spatial and temporal adaptivity reduce the execution time compared to the base method. The improvements from temporal adaptivity are consistently around 1.25x while the spatial adaptivity shows a larger range of improvements between 1.23x and 2.86x. Combining both adaptive techniques provides an improvement of up to 3.58x. Conclusions. Both spatially and temporally adaptive techniques are viable ways to improve the performance of a DEM-based snow simulation. The current implementation has some issues with performance overhead and with the visual results while using spatial adaptivity, but there is a lot of potential for the future. / Bakgrund. Fysikbaserad snösimulering är beräkningsmässigt dyrt och ännu inte tillämpligt på realtidsapplikationer. Några av de viktigaste faktorerna för denna kostnad är den komplexa fysiken, stora mängden partiklar och det lilla tidssteg som krävs för en högkvalitativ och stabil simulering. Förenklade metoder, såsom höjdkartor, används istället för att efterlikna ansamlingen av snö. Ett sätt att förbättra prestandan är hitta sätt att göra färre beräkningar. Inom området datorgrafik har adaptiva metoder utvecklats för att fokusera beräkningen där den behövs som mest. Dessa verk kommer att användas som inspiration för detta arbete. Syfte. Detta examensarbete syftar till att minska den totala partikelbelastningen för en befintlig applikation baserat på Discrete Element Method (DEM), och därigenom förbättra prestandan. Målet består av följande mål. Integrera en rumslig metod, och därigenom minska det totala antalet partiklar genom partikelsammanslagning och -splittring, och implementera en tidsmässig metod, och därigenom minska arbetsbelastningen genom att frysa vissa partiklar i tiden. Båda dessa teknikers prestanda kommer sedan att testas och analyseras i flera scenarier. Metod. Metoder för rumslig- och tidsmässig adaptivitet implementerades i en befintlig snösimulator. Metoderna både mättes och jämfördes med hjälp av kvantitativa tester i tre olika scener med varierande partikelantal. Resultat. Prestandatester visar att både den rumsliga och tidsmässiga adaptiviteten minskar exekveringstiden jämfört med basmetoden. Förbättringarna från tidsmässig adaptivitet är konsekvent runt 1,25x medan den rumsliga adaptiviteten visar en större bredd av förbättringar mellan 1,23x och 2,86x. Kombinering av båda adaptiva teknikerna ger en förbättring på upp till 3,58x. Slutsatser. Både rumsligt och tidsmässigt adaptiva tekniker är användbara sätt att förbättra prestandan för en DEM-baserad snösimulering. Den nuvarande implementationen har vissa problem med prestanda och med de visuella resultaten vid användning av rumslig adaptivitet, men det finns mycket potential för framtiden.

This thesis covers the development process of implementation, and evaluation of a softbody physics engine for convex polygon objects. The main feature is implementation of adynamic polygon collider that represents a polygons shape correctly, while still being ableto collide with other objects in the simulation. Objects are able to deform both temporarily and permanently using springs with distance constraints. Pressure simulation is alsoimplemented to simulate inflated polygons. The physics bodies does not feature frictionbetween objects, only friction against a static boundary of the simulation. The engine isthen evaluated in order to determine if it can run in real-time which is one of the goals.When it comes to the simulation, Verlet-integration will be used for updating the positions of particles, and every polygon will be built using these particles, and combinedusing certain constraints to make the particles act as one combined object. The main problem that will be solved is the interpenetration solver, which ensures that polygons do notoverlap, and two formulas will be combined to solve this problem. The collision detectionmethod uses line intersections to determine if objects are overlapping, this method endedup being quite expensive for polygons with a lot of vertices. One optimization techniqueis implemented which is axis-aligned bounding boxes around objects which improvedperformance significantly, which also makes the engine more viable for real-time simulations. The physics engine in this report is deterministic using a fixed time-step, dynamictime-step is not tested. The engine also only supports discrete collision detection.

Computer graphics is a branch of Computer Science that specializes in the virtual representation of real-life objects in a computer screen. While the past advancements in this field were commonly related to entertaining media industries such as video games and movies, these have found a use in others. For instance, they have provided a visual aid in medical exploration for healthcare and training simulation for military and defense.Ever since their first applications for data visualization, there has been a growth in the development of new technologies, methods and techniques to improve it. Today, among the most leading methods we can find the Volumetric or Volume Rendering techniques. These allow the display of 3-dimensional discretely sampled data in a 2dimensional projection on the screen.This thesis provides a study on volumetric rendering through the implementation of a real-time simulation. It presents the various steps, prior knowledge and research required to program it. By studying the necessary mathematical concepts including noise functions, flow maps and vector fields; an interactive effect can be applied to volumetric data. The result is a randomly behaved volumetric fog. The implementation issues, intricacies and paradigms are reflected upon and explained. The conclusion explores the results while these illustrate what can be accomplished using mathematical and programming notions in the manipulation of graphic data. / Datorgrafik är en filial inom datavetenskap som specialiserar sig på realistisk virtuell representation av verkliga objekt på en datorskärm. Medan de tidigare framstegen inom detta område vanligtvis var relaterade till underhållande medieindustrier som videospel och filmer, hade dessa hittat en annan användning i andra. De har tillhandahållit ett visuellt stöd inom bland annat sjukvård, arkitektur, militär och försvar och utbildning.Helt sedan deras första applikationer för visualisering av data har det skett en tillväxt av ny teknik, metoder och tekniker för att förbättra datarepresentationen. Idag, bland de mest ledande metoderna, kan vi hitta Volumetric eller Volume Renderingtekniker. Dessa möjliggör visning av 3-dimensionell diskret sampling av data i en tvådimensionell projektion på skärmen.Dennaavhandling ger en studie om volumetrisk rendering genom en realtidsimulering. Den presenterar de olika stegen, kunskapen och forskningen som krävs för att simulera den med hjälp av de matematiska grunderna som gör det mycket eftertraktat och även beräkningsproblematiskt. Implementeringsfrågor, komplikationer och paradigmer återspeglas och förklaras medan resultaten illustrerar vad som kan åstadkommas med matematiska och programmeringsmeddelanden när de tillämpas på manipulering av grafisk data.

No description available.