Bidirectional power switching devices are needed in many power management applications, particularly in lithium-ion battery protection circuitry. A monolithic bidirectional power switch fabricated with a simplified CMOS technology is introduced in this dissertation. Throughout the design process, ISE TCAD tool plays an important role. Design variables are carefully analyzed to improve the device performance or yield the best trade off. Optimization is done with the help of TCAD simulation and theoretical calculations. The device has been successfully fabricated using simplified 0.5 micron CMOS process. The experimental result shows a breakdown voltage of 25V. Due to the interdigitated source to source design, the inter-terminal current flowing path is effectively reduced to a few microns. The experimental result shows an ultra low specific on resistance. In comparison with other bi-directional power semiconductor switches by some major semiconductor manufacturers, the proposed BDS device has less than one half of the specific on resistance, thus substantially lower on state power loss of the switch. The proposed BDS device has a unique NPNPN structure, in comparison with NPNP structure, which is the analytical structure for CMOS latch-up, the proposed device inherently exhibits a better latch up immunity than CMOS inverter, thanks to the negative feed back mechanism of the extra NPN parasitic BJT transistor. In order to implement the device into simulators like PSPICE or Cadence IC Design, a compact model named variable resistance model has been built. This simple analytical model fits quite well with experimental data, and can be easily implemented by Verilog-A or other hardware description languages. Also, macro modeling is possible provided that the model parameters can be extracted from experimental curves. Several advanced types of BDS devices have been proposed, they exceed the basic BDS design in terms of breakdown voltage and /or on resistance. These advanced structures may be prominent for further improvement of the basic BDS device to a higher extend. Some cell phone providers such as Nokia is already asking for higher breakdown voltage of BDS device, due to the possibility of incidentally insert the battery pack into the cell phone with wrong pin polarity. Hopefully, the basic BDS design or one of these advanced types may eventually be implemented into the leading brand cell phone battery packs.

With the rapid development of industrialization and urbanization, industrial development and population growth drive the expansion of urban space, urban transportation demand shows the characteristics of spatial decentralization and diversification, and transportation travelers' requirements for mobility, accessibility, and comfort of transportation travel services are enhanced. Mobility on demand (MoD) services such as DiDi and Uber are new modes of public transportation, bringing many new opportunities and challenges. MoD travel services, shared bicycles, and other complementary public transport modes are rapidly developing in the "Internet +" environment, serving the "one mile" before and after the residents' travel. MoD technologies play an important role as a feeder to the main public transportation lines, helping to increase public transportation patronage and improve the speed of travel for residents. In this context, the study aims to develop a multi-modal public transportation system network design methodology to provide better operational coordination between different modes of transportation and to provide faster travel services. In order to promote better coordination between different transportation modes and to provide theoretical and methodological support for the development of a multi-modal public transportation system network design system, a bi-level planning model for this problem is first constructed. The upper-level planning model is used to minimize the total travel time and cost of passengers and the economic cost of public transportation operators, and to decide which bus lines to operate, the structure of bus lines, and the frequency of operating bus lines; the lower-level operating model is used to assign passengers to make travel mode choices and to carry out traffic distribution of the public transportation network based on the minimum number of interchanges. Then, based on this bi-level planning model, an improved genetic algorithm is developed to solve the upper-level public transportation network planning problem, in which the algorithm for passenger flow allocation in the lower-level planning model is nested in the genetic algorithm.  Finally, the developed methodology is validated for the benchmark Mandl network design by comparing with the traditional public transportation network. The results show that the multi-modal public transportation network can effectively reduce passenger travel time compared with the traditional public transportation network at similar costs. Finally, we applied the network design method for the Barkarby area in the north of Stockholm, Sweden. The results show that it is appropriate to allocate mobility on demand vehicles in this area. The constructed model and the proposed algorithm are scientifically valid and can provide theoretical methodological reference and decision support for engineering practice.

Autonomous heavy vehicles will enable the promise of decreased energy consumption through the ability to platoon in closer formation than is currently safe or legal. It is therefore increasingly important to understand the complex and dynamic wake interactions between vehicles operating in close proximity for aerodynamic gains. In recent years, a growing body of research has documented a bi-stable, shifting wake generated behind the Ahmed reference bluff body. At the same time, studies of platooning Ahmed bodies have focused on changes to the body forces and moments at different following distances or lateral offsets, typically based around time-averaged measurements or steady-state CFD. The present study attempts to understand the implications of bi-stability in the wake of two square-back, platooning Ahmed bodies, given the potential for transient instabilities. Temporally-correlated static pressures were measured on two identical wind tunnel models at various following distances to uncover the time-dependent interactions between platooning vehicles. Bi-stability is highly dependent on symmetry and the uniformity of oncoming flow, and it is shown that a shifting bi-stable wake behind the lead vehicle leads to correlated, bi-stable flow patterns on the following vehicle, even in the absence of a lateral offset. At a following distance of 0.25L, pressure data indicated there may be a point where this bi-stable behavior reaches a critical point between suppression and amplification, significantly affecting the aerodynamic loads on the lead vehicle. This leads to the conclusion that bi-stable wake interactions between vehicles may be useful to consider in the context of real-time organization of vehicle platoons.

The DC House project strongly relies on renewable energy sources to provide power to the house for various loads. However, when these sources are unable to provide power at a certain time, a back-up energy source from a battery must be readily available to fulfill the house’s power needs. This thesis proposes a bi-directional flyback power converter to allow a single-stage power path to charge the battery from and to discharge the battery to the DC House 48 V system bus. The design, simulation, and hardware prototype of the proposed flyback bi-directional converter will be conducted to demonstrate its feasibility. Results from a 35W prototype demonstrate the operation of the proposed converter for both charging and discharging purposes.

Testing done on the flat-back Ahmed Body and other bluff bodies has shown the existence of a bi-stable reflectional symmetry-breaking wake at Reynolds numbers ranging from 340 to 2.41 x 106. Several methods of flow control, both active and passive, have been used to improve the efficiency of the Ahmed body but their effect on the bi-stable nature of the wake has not been investigated. This work details the experimental investigation done to determine if piezoelectrically driven synthetic jet actuators are capable of suppressing the bi-stable wake effects observed behind the Ahmed Body. The synthetic jets were designed and manufactured to have a maximum total coefficient of momentum of 1.0E-3 with a frequency range up to 2000 Hz or F+ = 17.25. The piezoelectric actuators used were bimorph bending disks with no center shim and were driven by a square waveform. Pressure data was collected from 25 pressure ports on the rear of the model at 625 Hz for 600 seconds per run and filtered using a lowpass filter at 35 Hz to remove interference. Center of Pressure probability distributions and Principle Component Analysis were used to identify wake shapes and modes. Results with no jet actuation showed good agreement with previously published work on the Ahmed Body. It was found that the actuation frequency had an effect on the ability of the synthetic jets to affect the wake. Actuating at F+ = 1 (116 Hz) showed a bi-stable wake with an even distribution between wake modes. Higher actuation frequencies showed either a skewed distribution with a weakening of the bi-stable effects (4 < F+ < 8) or a complete removal of the bi-stable distribution (8 < F+ < 12). Frequencies higher than F+ = 12 did not show any effect on the bi-stable distribution. There was a negative correlation between actuation frequency and average wake pressure; it is theorized that the synthetic jets enhance mixing in the shear layer around the recirculation bubble in the wake to decrease average pressure.

No description available.

No description available.

Lysosomal storage disorders are a group of rare neurodegenerative diseases that are collectively common, sharing many aspects with other neurodegenerative disorders, including substrate build-up and neuroinflammation. The GM2 Gangliosidoses, Tay-Sachs disease and Sandhoff disease, are pathologically overlapping lysosomal storage disorders, with high prevalence within specific ethnicities. Their effects are neurologically devastating and often fatal at young ages. Current treatments only slow or stall an inevitable decline in health. Novel treatment targets are needed for these disorders, and others with similar pathologies. In these works we demonstrate the negative effect the inflammatory cytokine tumour necrosis factor-alpha has on survival of a model of Sandhoff disease. We demonstrate its role in the upregulation of astrogliosis, and apoptosis, and we present evidence that this effect on astrogliosis occurs through an upregulation of the JAK-2/STAT3 pathway. Though fruitful, a singular focus on inflammation/gliosis in these diseases has left a vacuum in the research into neuron specific molecular processes. We observe the development of inflammation, astrogliosis and neuronal processes in our model, and demonstrate a bi-phasic disease progression, in which early onset microgliosis precedes terminal astrogliosis, apoptosis, and a decline in excitatory glutamate receptors, suggesting neuron-specific malfunction. Furthermore, we show that knockout of the synaptic protein neuronal pentraxin 1 retards neurodegeneration and extends the lifespan of Sandhoff disease mice, independent of inflammation or astrogliosis. Through electrophysiology, we provide evidence of dysregulation of glutamate receptors in Sandhoff disease, and show that knockout of neuronal pentraxin 1 provides rescue from this dysregulation. This work expands on research into gliosis in GM2 gangliosidoses, presents the finding of a novel protein isoform, and presents a new focus on non-glial disease mechanisms and treatments for these and other neurodegenerative disorders. / Thesis / Doctor of Philosophy (PhD) / Lysosomal storage disorders are a group of neurological diseases that are debilitating, and often fatal at a young age. Two diseases of this group- Tay-Sachs disease and Sandhoff disease – are similar in their causes and symptoms. Current treatments for these diseases only slow or stall an inevitable decline in health. New targets for treatment are required, and we provide data suggesting several proteins that may fit this criterion. We also provide evidence of the discovery of a new form of one of these proteins, which is found in high levels in the disease, indicating it may be important in these and other neurodegenerative diseases. Finally, we provide findings indicating that a certain cell type, which is largely ignored in current research for these diseases, may be important in the disease progress. These findings increase our knowledge of Tay-Sachs disease and Sandhoff disease, and open new avenues for medicinal intervention.

Ett Business Intelligence-verktyg är ett system som tar vid där ett affärssystem slutar och som utvecklats för att stödja användare på ledningsnivå att exportera, strukturera samt analysera data och information från andra system. Karlstads universitets BI-verktyg, Kuli, är ett exempel på ett sådant system som hämtar data från flera olika databaser inom universitetet. Men för att systemet ska kunna fylla sitt syfte är användarnas kunskap och användning avgörande.Syftet med denna kandidatuppsats har varit att just bidra med kunskap om systemanvändningen av Kuli till systemförvaltarna. Mina frågeställningar gällde: (1) hur systemet används och (2) användares attityd till systemet. En semistrukturerad intervjuform användes för att utforska olika användares perspektiv och roller, där intervjuguiden bestod av öppna frågor som gav intervjupersonen utrymme att beskriva sina uppfattningar fritt.Studien baseras på sex intervjuer och resulterade i ett förslag på modell som visar på två huvudsakliga syften med användningen, tre olika varianter av användare samt en kombination av syfte och användare som mynnat ut i två idealtyper. Resultaten visade bland annat på systemets utvecklingspotential och behovet av utbildning hos användarna. Uppsatsen avslutas med förslag på förbättringar som exempelvis tidsstämpel när data hämtas in och ett mer användarvänligt gränssnitt. Dock är undersökningen baserad på ett begränsat antal deltagare och bör kompletteras med ytterligare studier som innefattar fler deltagare samt studier av systemets funktioner för användarloggar. Nyckelord: BI, Business Intelligence, ekonomistyrning, användbarhet, användaracceptans.

Née d'un désir de mettre en avant le travail novateur d'enseignants qui sortent des sentiers battus, notre recherche multicas a pour objectif de décrire les pratiques déclarées d'enseignants en contexte franco-ontarien qui utilisent la littérature bi-/plurilingue. Ce type de littérature permettrait, entre autres, de valoriser et de mettre à profit le répertoire linguistique pluriel des élèves qui évoluent dans un contexte minoritaire. À ce jour, les recherches s'intéressent davantage aux avantages liés à ce médium et ne décrivent que peu, de façon concrète, comment il est utilisé en salle de classe. À l'aide d'un questionnaire portant sur l'utilisation de cette littérature et d'une série d'entrevues semi-dirigées, nous avons eu accès aux différentes pratiques déclarées de trois enseignants qui œuvrent à l'élémentaire et de deux enseignants qui œuvrent au secondaire dans des écoles de langue française en Ontario. Plus précisément, ils nous ont décrit, par l'entremise d'un maximum de trois livres bi-/plurilingues qu'ils ont choisis, leurs façons de mettre en œuvre les trois moments clés d'une pratique d'enseignement en lecture : avant la lecture, pendant la lecture et après la lecture. Les résultats montrent que les enseignants utilisant la littérature bi-/plurilingue emploient des pratiques déjà décrites dans la recherche scientifique sur l'utilisation de la littérature monolingue et bi-/plurilingue. Cela étant, ils en créent également de nouvelles, afin de s'adapter aux spécificités des œuvres qu'ils emploient et de valoriser la diversité présente dans leur classe.