21793 research outputs found
Sort by
Induction Machine Emulation for Supply Faults
Get PDFPower hardware-in-the-loop (PHIL) is increasingly being recognized as an effective real time emulation technique to mimic electrical dynamics of machines with the help of real time digital systems using real time simulator like Opal-RT, RTDS, D-space etc. In PHIL machine emulation, a power electronic converter or a linear amplifier emulates the behavior of electrical machines which are used in several applications such as Transportation, Aerospace / Military, Automotive, e-vehicle, Grid and motor Applications. Using these emulation techniques, various complex control algorithms or different configurations of controllers/drives for electrical machines can be tested, and also allows the testing of complex control strategies of an ac microgrid with critical industrial machines.
The emulation techniques can be used to represent new machine prototypes thus reducing the time to market of the complete drive system significantly. That is prior to the installation of a physical machine, testing of an electric drive or micro grid can be done with the help of a real time machine emulator. Therefore, if the drive controller fails, it will not jeopardize the life of a costly machine. Different loading profiles can be tested. In addition, a PHIL based machine emulation can be particularly useful to emulate faulted machine behavior. A machine undergoes wear and tear and may develop faults such as winding faults, bearing faults, or rotor eccentricity etc. If such machines are being emulated, their corresponding impact on the driving inverter, controller and power system can be studied without implementing these faults on a healthy motor. In fact, these emulation related research areas explore the feasibility of employing a real machine under such atypical conditions. Furthermore, machine emulation also provides an idea of detecting specific faults in advance.
The main research areas focused on this research are development of machine models of high accuracy, development of an emulator controller to attain dynamic current/voltage tracking capability and research in emulator configuration. Several atypical conditions are considered including short circuit faults, open circuit faults and switching faults. The mathematical models are developed considering the machine steady state and transient behavior under starting and different fault operating conditions of the machine. The emulator chosen is a linear amplifier, because of its high bandwidth and performance. However, in comparison to a low bandwidth switched power amplifiers, it also possesses maximum current limitations. The emulator control strategies consider the abnormal conditions to which the machine is exposed. Hence, the emulator in this research work can replace the real machine effectively. Also, this method of emulation can be applied to any machine such as permanent magnet synchronous machine, synchronous reluctance machine, wound rotor induction machine etc. Especially, when the machine is rated in the MW power range, the developed emulator can be used with scaled down parameters.
In this PhD work, the main components in the emulator test bench include a real time system, back-to-back converters or linear amplifiers, link filters, required sensors and the grid. The developed IM emulator test bench can be used for studying the performance of the grid or drive control system for various grid faults, drive faults and other severe transient conditions. To validate the designed machine emulator system and its control philosophy, results are taken with a real 5 hp machine under same transient conditions.
On the other hand, this PHIL technology is also employed for grid emulation. An interface algorithm in the power hardware in the loop determines the accuracy and stability of emulation. Conventionally, this PHIL setup uses the ideal-transformer-method (ITM) as an interface algorithm between the device-under-test (DUT) and the real-time grid simulation model. The closed-loop PHIL interface with the DUT is usually stabilized using low-pass filters in the feedback path. Such filters stabilize the closed-loop PHIL interface, but with compromised accuracy. To improve the accuracy of the PHIL interface, this research work presents a method to design an optimal feedback compensator. This method depends on the type of physical filter topology used for the device under test.
To summarize, this research work represents 1) different induction machine emulators for different conditions of the grid and drive converters. This includes grid faults and test drive faults. 2) A grid emulator is designed with PHIL technology to test balanced and unbalanced resistive loads, islanding and grid connected modes of a distributed energy source (DER). The results obtained from the analysis and simulation for machine emulation and grid emulation are validated experimentally
Playing at Romance Otome Games, Globalization and Postfeminist Media Cultures
Get PDFOtome games is a category of games originated in Japan that are marketed specifically to women. While genres in this particular category tend to range from RPGs to visual novels (the latter being the most common), they notably have the following common features: these games contain a system that allows the female player character to form relationships with the mostly straight and predominantly male game characters, they have simple controls, and they are related to other multimedia products, often imitating plots and art styles from manga and anime. Moreover, romance is often features as a part the games’ narratives, often imitating plots from shoujo manga. Although otome games occupy a niche sector of the game industry in its country of origin, the number of titles that are being adapted for audiences outside of Japan have steadily increased during the past decade.
This thesis explores this largely unexplored category of games, its players and the ways in which these titles have migrated out of Japan. Focusing on games, platforms and its predominantly female fandom, I examine cultural sensibilities, economies and online social formations that allow these migrations to happen. I apply a mixed-methods approach of textual analysis and interviews to help formulate my analysis of these games and the fan communities, which operate quite similarly to Radway’s book clubs. The results of this study indicate how communities and postfeminist media cultures both allow women to shape discourses around gender and romance, but also at the same time limit these discourses in ways that are beneficial to companies that create and localize these games
Second language use at work and school: A study of errors, satisfaction, and stress appraisals
Get PDFThe main purpose of this study was to examine how miscommunications may be perceived as stressors by people who do not have the common business language at their workplace as their first language, and how this can affect job satisfaction. It also examined if these relations will be different when people perceive stressors related to speaking a second language as a challenge and/or a hindrance. I hypothesized that employees’ job satisfaction is negatively related to their second language use and communication error frequency. I further hypothesized that hindrance stress appraisals and challenge stress appraisals are moderators of these negative relations, where hindrance stress appraisals strengthen the relations and challenge stress appraisals weaken the relations. A secondary purpose of this study was to test these same hypotheses in the school domain. This study was done by gathering data from a sample of undergraduate students (N = 250), some of whom were employed (N = 219 for work domain analyses and N = 179 for school domain analyses). In the work domain, regression results showed that communication error frequency is negatively related to job satisfaction, consistent with the hypothesis, but with no moderating effect of stress appraisals, in contrast to the hypotheses. Results also showed that the relation between second language use and job satisfaction is negative and significant when second language use challenge appraisal is low and it becomes non-significant when second language use challenge appraisals increase, which was in line with the hypothesis. In the school domain, regressions demonstrated that school satisfaction has no significant relation with second language use, in contrast to the hypothesis. However, in line with the hypotheses, the relation between communication errors and school satisfaction is negative and significant when communication error challenge appraisal is low, and it becomes non-significant when communication challenge appraisal increases. These results suggest that it is important to find ways to make people feel that making communication errors are educational and promote their personal growth. Future research directions are discussed
LC-MS/MS-Based, Label-Free, Peptide-Centric, Quantitative Proteomics of the H2O2 Stimulon in Wild-Type S. Cerevisiae Cells vs Those Deleted for the H2O2 Sensor, Ccp1
Get PDFReactive oxygen species (ROS) such as hydrogen peroxide (H2O2) can be harmful to cells. However, cells adapt to sublethal doses of H2O2 by the enhancement of antioxidant synthesis and shifting their carbon flux to NADPH generation. Cytochrome c peroxidase (Ccp1) is a heme-based protein located in the intermembrane space of yeast mitochondria that functions as a sensor of H2O2. To fully explore the H2O2-sensing role of Ccp1, we compared the H2O2 stimulon in wt and ccp1Δ Saccharomyces cerevisiae cells (BY4741 strain) using label-free peptide-centric, quantitative proteomics. Cells were grown to mid-log phase, challenged with 0.4 mM H2O2, and whole-cell lysates were prepared 10 and 60 min later for three biological replicates. All the proteins in each lysate were concentrated into a single band on a 6% stacking gel for tryptic digestion and peptide analysis by nanoLC-MS/MS. A total of 2222 proteins were quantified and identified from their unique peptides (14,642) in the biological replicates. The stimulated and repressed proteins were analyzed using an abundance ratio (R) calculated by Proteome Discoverer v2.4, and Ccp1’s role was evaluated through the examination of proteins up- and downregulated following H2O2 challenge. Our results suggest that Ccp1 influences the abundance of key antioxidant enzymes such as Ctt1, Trx2 and Prx1 by effecting the levels of transcription factors involved in H2O2 signaling, including Yap1 and Hsf1. Ccp1 deletion alters the abundance of proteins that are important in NADPH production such as Rki1 and Sol3. These proteomics results combined with published biochemical data provide new insights into how Ccp1 contributes to the coordination of cellular defensive mechanisms and the shifts in metabolic pathways following H2O2 challenge
LiFi Transceiver Designs for 6G Wireless Networks
Get PDFDue to the dramatic increase in high data rate services, and in order to meet the demands of the sixth-generation (6G) wireless networks, researchers from both academia and industry have been exploring advanced transmission techniques, new network archi-
tectures and new frequency bands, such as the millimeter wave (mmWave), the infrared, and the visible light bands. Light-fdelity (LiFi) particularly is an emerging, novel, bidirectional, high-speed and fully networked optical wireless communication (OWC) technology that has been introduced as a promising solution for 6G networks, especially for indoor connectivity, owing to the large unexploited spectrum that translates to signifcantly high data rates.
Although there has been a big leap in the maturity of the LiFi technology, there is still a considerable gap between the available LiFi technology and the required demands of 6G networks. Motivated by this, this dissertation aims to bridge between the current research literature of LiFi and the expected demands of 6G networks. Specifcally, the key goal of this dissertation is to fll some shortcomings in the LiFi technology, such as channel modeling, transceiver designs, channel state information (CSI) acquisition, localization, quality-of-service (QoS), and performance optimization. Our work is devoted to address and solve some of these limitations. Towards achieving this goal, this dissertation makes signifcant contributions to several areas of LiFi. First, it develops novel and measurements-based channel models for LiFi systems that are required for performance analysis and handover management. Second, it proposes a novel design for LiFi devices that is capable of alleviating the real behaviour of users and the impurities of indoor
propagation environments. Third, it proposes intelligent, accurate and fast joint position and orientation techniques for LiFi devices, which improve the CSI estimation process and boost the indoor location-based and navigation-based services. Then, it proposes novel proactive optimization technique that can provide near-optimal and real-time service for indoor mobile LiFi users that are running some services with high data rates, such as extended reality, video conferencing, and real-time video monitoring. Finally, it proposes advanced multiple access techniques that are capable of cancelling the efects of interference in indoor multi-user settings. The studied problems are tackled using various tools from probability and statistic theory, system design and integration theory, optimization theory, and deep learning. The Results demonstrate the efectiveness of the proposed designs, solutions, and techniques. Nevertheless, the fndings in this dissertation highlight key guidelines for the efective design of LiFi while considering their unique propagation
features
Toward Erobotics: An Investigation of the Relationships Between Stigma, Personality, Sexual Arousal, and Willingness to Engage Erotically with Robots
Get PDFThe rise of erobots (erôs + bots)—artificial erotic agents, such as sex robots—offers new opportunities for intimate experiences with machines. Their advent has also polarized academic and public debates: some denounce their risks, while others defend their benefits. Yet, the scientific study of human–machine erotic interaction and co-evolution remains limited: it lacks comprehensive theoretical models, and its empirical literature is scarce and fragmented. There is a need for a new, unified transdisciplinary field of research focusing on such phenomena, and guiding the development of beneficial technologies. We call this field erobotics. As a theoretical contribution to this new discipline, Chapter 2 defines erobotics and its related concepts, proposes a model of human-erobot interaction and co-evolution, and suggests a path to design beneficial erotic machines. As an empirical contribution to erobotics, this thesis examines some of the sociocultural, individual, and situational factors highlighted by this model. Specifically, it investigates the relationships between perceived stigma, personality traits, sexual arousal, and people’s willingness to engage erotically with robots. Chapter 3 shows that stigma related to erotic technology exists and increases as a function of products’ human-likeness. Chapter 4 shows that the willingness to engage with and perceived appropriateness of using sex robots more closely relate to erotophilia and sexual sensation seeking, rather than technophilia, non-sexual sensation seeking, and Big-Five traits. Chapter 5 shows that sexual arousal increases willingness to have sex with robots. In these three chapters, men were more interested in engaging erotically with robots than women. Together, these findings suggest that erotophilic sensation seekers—especially, men—may become the primary users of erobots, and that sexually aroused individuals may be more willing to engage erotically with such machines: potentially influencing their design and our relationship with them. Ultimately, this thesis founds erobotics and opens future directions for the study of human-machine erotic interaction and co-evolution
Climate Futures: A 360 mapping experience of Montreal under Climate Change
Get PDFThe planet is facing massive climate change effects; Canada itself is warming at an unprecedented rate in comparison to the rest of the world. However as inland populations living in Montreal, we don’t often see these effects day-to-day. In addition, the media surrounding the future is often saturated with images of climate apocalypse that annihilate us. This makes it increasingly difficult to visualize a world that isn’t hopeless, and how we will survive in climate change. In this research-creation project, I question if there are hands-on methods to visualize a future world, where we thrive despite, and alongside, climate challenges. This research-creation project looks at the interacting aspects of climate change, critical mapping, speculative futurisms, and marginalized community voices through the creation of a ‘future map’ of Montreal. To explore this, I collect interviews from 6 community members/activists and render their visions into 360 images built into a digital map. I provide context with theories of world-building, mapping, and the creation process itself, bringing to life the participants’ visions of the future. I then describe how marginalized viewpoints and anti-oppressive frameworks build a better, tangible vision of tomorrow. I use the concept of remediation to explain the process of building futures in order to ‘fix’ society. To summarize, a critical mapping and 360 experience of Montreal under climate change will increase the body of work on climate change projection from a community perspective, and explore more embodied, hopeful, and grounded experience of climate futures
Rheological characterization of polymer melts with bimodal distributions
Get PDFPolymer melt exhibits complex relaxation and flow behaviors when subject to some
form of deformation. The ensued stress experienced by the melt depends on the entire deformation
history and not just the deformation rate or the magnitude. To better anticipate
the response of melts to deformations, an understanding of their molecular structure is
essential. This understanding helps not only in optimizing the process conditions, which
turn to be big cost savers, but also enables the production of end-products with controlled
and desirable properties.
The research presented here establishes correlations between the features of the molecular
weight distributions (MWD) and the rheological behavior of broadly distributed bimodal
HDPE and well tailored distributions of polybutadiene. We start by characterizing
a set of high-density polyethylene (HDPE) materials which possess very high levels of
polydispersity. Then, using statistical learning, the most important features influencing
the rheological behavior are identified. We show that by using just the shape features of
the MWD the relaxation behavior of the melt can be inferred. We proceed to investigate
the behavior of polymer melt at the interface. Using the simple shear flow experimental
setting, we eliminate the possibility of contributions from flow induced fractionation
and show for the first time that surface segregation could occur in the absence of bulk
shear gradient. We additionally show that apart from the surface enrichment being shearrate
dependent, the enrichment-depletion transition point also occurs at a much lower
molecular weight value than predicted in literature. We then proceed to show the key
role played by the short chain in surface fraction. By using bi-disperse polybutadiene
designed to vary in both short chain length and volume, an enhanced relaxation of the
melt was shown to positively improve the polymer surface fraction
Advanced User-centric Modeling for Future Wireless Communication Networks: Performance Analysis and Optimization
Get PDFDue to the increasingly growing demand for high data rates and a massive number of connected devices, future wireless communication networks are required to provide much more resources than the current networks can do. As an emerging
solution for future cellular networks, dense deployment of small cell base stations (BSs) has received a great deal of attention both in academia and industry. A major challenge in dense cellular networks is the interference experienced by the user from
its neighboring active BSs. The effect of such interference is more deleterious at cell-edge users which limits the density of deployed BSs.
An effective promising solution is to move from a cell-centric to a user-centric paradigm which allows each user to be connected to a set (cluster) of BSs instead of being associated with a single one. This will mitigate the interference effect and remove the cell boundaries, i.e, no cell-edge users. In this thesis, we develop novel
BS clustering models to enable a user-centric BS cooperation for future wireless networks. Unlike the existing clustering models, where a user is served by a cluster of BSs with fixed size (either a fixed number of BSs or fixed cluster radius), our proposed models adapt the cluster of each user dynamically based on its channel condition and quality-of-service (QoS) requirements.
To design user-centric networks, we focus on several technologies introduced for future wireless wireless communication systems such as millimeter wave (mmWave) and terahertz (THz) networks, unmanned aerial vehicle (UAV)-assisted networks, hybrid multi-tier networks, and energy harvesting networks. We first investigate the performance of a user-centric mmWave network under the proposed dynamic BS clustering model using tools from stochastic geometry. To maximize the system spectral efficiency, an optimization framework for the user’s serving cluster is developed. Then, a user-centric THz system is designed to compensate for the
high pathloss and hence improve the coverage of THz networks. Both dynamic and static clustering approaches are considered, based on which we study the coverage probability of the user-centric THz network by using stochastic geometry. Then, to design an energy-efficient and reliable air-to-air connection in UAV networks, we design a 3D user-centric clustering model where a set of UAV transmitters spatially distributed in a 3D space in the sky are carefully selected to serve another UAV receiver. Analytical expressions for the spectral efficiency and energy efficiency of this
user-centric UAV network are provided and an efficient and tractable optimization framework to maximize its energy efficiency is developed.
In this thesis, we also implement a user-centric BS clustering for hybrid networks where THz, mmWave, and sub6-GHz BSs coexist. In this system, a user can be associated with the best BS cluster, from either a sub6-GHz, mmWave or THz tier based on either the maximum SINR criterion or the maximum rate criterion. Thus, with carefully planned networks, enabling hybrid user-centric wireless systems can provide ultra-high rates while maintaining sufficient coverage in future multitier networks. Furthermore, we adopt the proposed user-centric clustering model to enhance the joint rate and energy coverage of cellular networks with simultaneous
wireless information and power transfer (SWIPT). For this setup, we aim to insure that the user can harvest sufficient energy in a given time slot and receive the required minimum data from a given serving cluster. Then, a mathematical optimization model for the time switching coefficient is developed to maximize the system joint rate and energy coverage performance. All analytical results are validated by simulation with comparison to some of the existing works, demonstrating that the proposed analytical frameworks are accurate and efficient in the design and deployment of future user-centric wireless networks
Witchy Methodologies: Bewitchment, Shapeshifting, and Communication with More-Than-Human Kin
Get PDFShapeshifting, spellcasting, salt circles: who are witches and why should we, as scholars, care to know more about them? My dissertation, “Witchy Methodologies: Bewitchment, Shapeshifting, and Communication with More-Than-Human Kin” examines the media and techniques of contemporary North American witchcraft — such as tools, spells, and communication with spirits, ancestors, and more-than-human kin — against a theoretical background that reaches towards feminist and unsettled positionalities. How does the witch act in / on the world in a way that opens tricky questions surrounding the methods we use to craft knowledge as well as who is deemed able to do so?
My dissertation is broken down into three chapters, where each chapter involves a set of media or techniques that witches use as well as their surrounding questions — Chapter 1: “Mirrors”; Chapter 2: “Knots,” and Chapter 3: “Fluids.” In Chapter 1, I look at mirrors, concentrating especially on the witches’ black scrying mirror that does not reflect, but, rather, divines. In chapter 2, I open a discussion of what I call the methodology of bewitchment and how it is involved with tricks and traps, such as knot spells, cauldrons, and animal familiars. In chapter 3, I focus on fluids; in particular water, blood, and ectoplasm. What is it, finally, that the techniques and tools of witches produce, if anything?
Ultimately, my dissertation is about communication. The tools and techniques that I discuss throughout may seem extraordinary but are in fact quotidian and widespread. We all communicate and seek to connect with more-than-human companions and kin. Rather than learning or making, witches’ methods offer a way of unlearning and unmaking the structures that define and bind the perimeters of the enlightened and empirical. How do witches and their techniques teach us to attune to the subtle frequencies of our environments and underworlds — and open our ability to listen