To give a realistic impression in a driving simulator for nighttime driving, there are many challenging aspects to consider. One of the most important aspects is the illumination caused by the headlights of the own vehicle. To give a realistic impression there is the need to consider the characteristics of the headlight in use to be able to represent main and dipped beam, but also to represent different models and types of headlights. Another important aspect is the dazzling effects caused by the light cast by other vehicles upon the driver. These effects are not only important to give a realistic and visually appealing simulation, but also to simulate blinding effects which may affect the drivers ability to perceive the traffic environment to a large degree. This thesis describes methods to simulate these vital aspects of night-drive simulation in real-time using the capabilities of today's graphics cards.

Tracking and understanding human gait is an important step towards improving elderly mobility and safety. This thesis presents a vision-based tracking system that estimates the 3D pose of a wheeled walker user's lower limbs with cameras mounted on the moving walker. The tracker estimates 3D poses from images of the lower limbs in the coronal plane in a dynamic, uncontrolled environment. It employs a probabilistic approach based on particle filtering with three different camera setups: a monocular RGB camera, binocular RGB cameras, and a depth camera. For the RGB cameras, observation likelihoods are designed to compare the colors and gradients of each frame with initial templates that are manually extracted. Two strategies are also investigated for handling appearance change of tracking target: increasing number of templates and using different representations of colors. For the depth camera, two observation likelihoods are developed: the first one works directly in the 3D space, while the second one works in the projected image space. Experiments are conducted to evaluate the performance of the tracking system with different users for all three camera setups. It is demonstrated that the trackers with the RGB cameras produce results with higher error as compared to the depth camera, and the strategies for handling appearance change improve tracking accuracy in general. On the other hand, the tracker with the depth sensor successfully tracks the 3D poses of users over the entire video sequence and is robust against unfavorable conditions such as partial occlusion, missing observations, and deformable tracking target.

De nationella styrdokumenten för gymnasiet påvisar att läraren skall undervisa om samt bedöma elevernas prestationer i språkhistoria. I dagsläget saknas det forskning om hur verksamma lärare skall didaktisera det språkhistoriska momentet i svenskundervisningen. Som konsekvens av detta blir momentet starkt bundet till de läromedel som används, där de språkhistoriska epokerna är tydligt avgränsade till att beskriva utveckling av det svenska språket ur en historisk aspekt. Därmed framträder det dilemma som denna studie har som syfte att belysa. En kvalitativ undersökningsmetod med semistrukturerade intervjuer användes för att söka svar till hur fem verksamma gymnasielärare i dagsläget undervisar i det språkhistoriska momentet. Centralt för studiens frågeställningar är hur respondenterna angriper de språkhistoriska epokerna i undervisningen samt hur de tydliggör det faktum att språkförändring är ett konstant fenomen. Studiens resultat visar att det språkhistoriska momentet får relativt lite utrymme i svenskämnet, möjligen till följd av att den lokala arbetsplanen lyser med sin frånvaro. Den undervisning som existerar är starkt bunden till de läroböcker som respondenterna använder sig av i undervisningen, men det blir tydligt att momentet får en erfarenhetspedagogisk prägel när det sätts i praktiken trots läroböckernas traditionella framställning. Respondenterna finner alternativa arbetssätt för att belysa de traditionella språkhistoriska epokerna som relaterar till elevernas förståelse om språket som fenomen och respondenterna är orädda för att konfrontera språkhistoriska fenomen när de dyker upp i kontext till övriga moment i svenskundervisningen.

Post-occupancy evaluations represent an important missed opportunity. While POEs are often used to inform design guides, and to support facility management, they are seldom used to support design decision-making. While there are several technical, methodological, and cultural impediments to the ongoing use of POE results in design, characteristics of POE data and data structure is an important, and often overlooked, impediment. Some evaluators have attempted to resolve this problem by involving actively as consultants in design teams or involving users, such as Placemaking or Process Architecture. Recent advances in conceptual data modeling provide another strategy to interface POE findings and design decision-making. This thesis uses EXPRESS modeling language to develop a conceptual data structure for POE data, and integrate POE data with as-built building descriptions. While this effort has the potential to develop an improved way to structure POE data and make it more useful, it is also an extension of ISO-STEP. This study develops a data structure based on post-occupancy evaluations of state and federal trial courtrooms conducted by the researcher. Thirty-one courtrooms were evaluated, resulting in usable data from 93 courtroom users in 26 courtrooms. An EXPRESS-G schema was developed and was translated into a relational database for holding data and running queries. The investigator illustrated a range of query-generated outcomes to support decision-making during design and design review. Such outcomes include exploring existing courtrooms, comprehending the types of design decisions implemented across federal and state courtrooms, identifying design decisions that have been rated favorably or otherwise by courtroom users, rating design decisions based on evaluation data from existing courtrooms, and predicting a designed environments supportiveness to task performance. Further, multivariate analysis of the POE data provides the first scientific investigation of courtrooms as work settings. Finally, eight key performance indicators of courtrooms were developed based on the POE data.

A novel solid state illumination source has been developed. A two terminal dual LED has been created with the ability to control the relative intensities of the two emission peaks by varying drive current. Doping profiles have been used to extend the dynamic range of the dual LED over other reported devices. Operation of the dual LEDs is explained as a function of drive current. In addition, novel use of phosphor mixtures allows the creation of a broadband spectral power distribution that can be varied using a dual LED as an excitation source. Combinations of phosphors that have varied excitation spectra provide the ability to selectively excite different phosphors with the different LED emission peaks. First and second generations of the two terminal dual LED and the phosphor combination are discussed. The final source has the ability to mimic the light of a blackbody radiator over a range of 3200 K - 5300 K. The development of a three terminal dual LED as a pump source was prohibited by the need for a III-nitride tunnel junction, that proved unattainable in the scope of this work. However, several novel doping schemes were investigated toward this end. Finally, a circadian light source has also been developed that can affect physiological changes in humans, and a light box for entrainment of circadian rhythms in rats has been built.

This dissertation includes two parallel topics: optical modeling of wavelength converters based on semiconductor optical amplifiers (SOA) and optical modeling for LEDs and solid state lighting. A steady-state numerical model of wavelength converters based on cross-gain SOAs is developed. In this model, a new model of the gain coefficient is applied. Each physical variable, such as the carrier density, gain coefficient, differential gain, and internal loss, spatially varies across the SOA cavity and is numerically calculated throughout the device. Increased accuracy over previous studies is achieved by including such spatial variations. This model predicts wavelength-dependent characteristics of a wavelength converter of the SOA in both large and small signal regimes. Some key performance factors of SOA wavelength converters. A hybrid method incorporating both guided wave optics and optical ray tracing is also developed to model LEDs and solid state lighting. This method can model either single wavelength or dual-wavelength LED structures with different die shapes and packages. The waveguide and diffraction optics are mainly used to model the near-field optics inside LED chips and its vicinity and to identify guided modes and leakage modes. Geometrical ray tracing is applied to model the far-field pattern and light interactions at different material interfaces, such as LED chip structures, LED package materials, and light scattering at those rough surfaces and textures. To improve LED light extraction efficiency, different LED die shapes and device structures can also be optimized using this method. New technologies for future research on SOAs and LEDs are also proposed.

The objective of the research was to develop high quality GaN epitaxial growth on alternative substrates that could result in higher external quantum efficiency devices. Typical GaN growth on sapphire results in high defect materials, typically 10⁸⁻¹⁰cm⁻², due to a large difference in lattice mismatch and thermal expansion coefficient. Therefore, it is useful to study epitaxial growth on alternative substrates to sapphire such as ZnO which offers the possibility of lattice matched growth. High-quality metalorganic chemical vapor deposition (MOCVD) of GaN on ZnO substrate is hard to grow due to the thermal stability of ZnO, out-diffusion of Zn, and H₂back etching into the sample. Preliminary growths of GaN on bare ZnO substrates showed multiple cracks and peeling of the surface. A multi-buffer layer of LT-AlN/GaN was found to solve the cracking and peeling-off issues and demonstrated the first successful GaN growth on ZnO substrates. Good quality InGaN films were also grown showing indium compositions of 17-27% with no indium droplets or phase separation. ZnO was found to to sustain a higher strain state than sapphire, and thereby incorporating higher indium concentrations, as high as 43%, without phase separation, compared to the same growth on sapphire with only 32%. Si doping of InGaN layers, a known inducer for phase separation, did induce phase separation on sapphire growths, but not for growths on ZnO. This higher strain state for ZnO substrates was correlated to its perfect lattice match with InGaN at 18% indium concentration. Transmission electron microscopy results revealed reduction of threading dislocation and perfectly matched crystals at the GaN buffer/ZnO interface showing coherent growth of GaN on ZnO. However, Zn diffusion into the epilayer was an issue. Therefore, an atomic layer deposition of Al₂O₃was grown as a transition layer prior to GaN and InGaN growth by MOCVD. X-ray and PL showed distinct GaN peaks on Al₂O₃/ZnO layers demonstrating the first GaN films grown on Al₂O₃/ZnO. X-ray photoelectron spectroscopy showed a decrese in Zn diffusion into the epilayer, demonstrating that an ALD Al₂O₃layer was a promising transition layer for GaN growth on ZnO substrates by MOCVD.

A Post-Occupancy Energy Analysis of the Gwinnett Environmental and Heritage Center conducted with the view of recommending optimizations that result in energy savings.

La synthèse d'une flamme animée dans un environnement 3D virtuel, reste à ce jour une tâche ardue, exigeant de judicieusement balancer réalisme et coût de calcul. Dans ce mémoire, nous présentons un ensemble de techniques pour sa simulation en temps réel tout en modélisant une interaction à des forces externes. Nous désirons minimiser son coût de calcul tout en préservant une apparence convaincante dans l'optique d'une intégration au sein de systèmes existants, n'affectant pas indûment leurs performances. Un champ de vélocité est extrait d'une simulation de ressorts et mis à profit dans le déplacement de chaînes de particules modélisant la forme de la flamme par l'entremise de la paramétrisation d'une surface NURBS. Considérant l'importance qu'ils ont sur notre perception de la combustion, nous prenons également soin de reproduire l'illumination, les ombres, et l'effet d'éblouissement qu'elle engendre. / The synthesis of an open flame in a virtual 3D environment, remains to this day an arduous task, requiring a wise balance between realism and processing cost. In this M. Sc. thesis, we present a set of techniques for its simulation in real time while also modeling the interaction with external forces. Our goal is to minimize the cost while preserving a convincing appearance, thus facilitating integration of the techniques into existing systems without unduly affecting their performance. A velocity field is extracted from a spring-mass simulation which contributes to moving chains of particules that are used in modeling the flame shape through the configuration of a NURBS surface. In light of the importance they have on our perception of combustion, we also take care to duplicate the lighting, shadows and bloom the flame gives rise to. / Vidéos et images des résultats disponible à : http://www.iro.umontreal.ca/labs/infographie/theses/fatnasss/

Current designs of high performance buildings utilize hourly building energy simulations of complex, interacting systems. Such simulations need to quantify the benefits of numerous features including: thermal mass, HVAC systems and, in some cases, special features such as active and passive solar systems, photovoltaic systems, and lighting and daylighting systems. Unfortunately, many high performance buildings today do not perform the way they were simulated. One potential reason for this discrepancy is that designers using the simulation programs do not understand the analysis methods that the programs are based on and therefore they may have unreasonable expectations about the system performance or use. The purpose of this study is to trace the origins of a variety of simulation programs and the analysis methods used in the programs to analyze high performance buildings in the United States. Such an analysis is important to better understand the capabilities of the simulation programs so they can be used more accurately to simulate the performance of an intended design. The goal of this study is to help explain the origins of the analysis methods used in whole-building energy simulation, solar system analysis simulation or design, and lighting and daylighting analysis simulation programs. A comprehensive history diagram or genealogy chart, which resolves discrepancies between the diagrams of previous studies, has been provided to support the explanations for the above mentioned simulation programs.