title: DEVELOPING AND TESTING IN VIVO MODELS TO EXAMINE THE EFFECT OF INFLAMMATION AND BARRIER FUNCTION IN THE FEMALE GENITAL TRACT IN THE CONTEXT OF SEXUALLY TRANSMITTED VIRUSES

contributor: Medical Sciences (Molecular Virology and Immunology Program)

abstract: A number of factors including epithelial barrier function, mucosal inflammation and HSV-2 infection are known to affect the early events of HIV transmission and pathogenesis in the female genital tract (FGT). We previously demonstrated that curcumin, a highly pleiotropic anti-inflammatory natural compound, can inhibit cytokine and chemokine production, epithelial barrier disruption and HSV-2 replication in vitro. Thus, the goal of the present study was to investigate the in vitro to in vivo translatability of the aforementioned study and the ability of curcumin to prevent mucosal inflammation and HSV-2 replication in a mouse model. The second objective of this study was to further our understanding of the genital epithelial barrier in vivo and develop an assay system that would allow for the experimental determination of in vivo genital barrier function. The work summarized in this thesis has furthered our understanding of the genital microenvironment and its relevance to HIV infection. Our results show that while crude curcumin decreased HSV-2 infection, it was most likely due to a physical barrier effect. Further examination with curcumin nanoformulations demonstrated that it was able to potently decrease TLR-induced inflammation in the FGT, particularly with direct application to the genital tissue, but not HSV-2 infection. We also established a simple, reliable and reproducible method to functionally assess changes in genital barrier function by measuring concentrations of dye in the blood following vaginal delivery. Using this system, we have demonstrated that Depo-Provera, a widely used progestin-based hormonal contraceptive that has been linked to HIV risk, severely reduces genital barrier function in vivo. This work emphasizes that inflammation and barrier function are critical avenues that should be explored in the development of more effective prevention and treatment strategies for HIV infection. Understanding causes of inflammation and barrier breakdown will also prove valuable in guiding the use of safer hormonal contraceptives and vaginal healthcare products in high risk women.

abstract: Thesis

abstract: Master of Science (MSc)


title: The 'Translating Subject': Tracing the History of a North American Feminist Literary Avant-garde

title: The 'Translating Subject'

contributor:
York, Lorraine
English

subject:
Canadian literature
American literature
women's writing
literary movements
North America
writing communities
feminism
poetics

abstract: This work examines women's relationships to language through the work of Canadian and American innovative women writers who write in, out of and through multiple non-English languages as a way of challenging English linguistic dominance and the patriarchal and imperial power structures upheld therein. The theoretical thrust of "The Translating Subject" is to explore the politics of multilingualism as an aesthetic strategy. Multilingualism, a notable strategy in women's writing of the last thirty years, permits the post-colonial writer to resist discursive colonization, as well as express bi-cultural identity through bilingual writing and what Evelyn Nien-ming Ch'ien calls "weird English." The three women about whom I write, Erin Mouré, Nicole Brossard and Kathy Acker, do not use multilingualism to express bi-cultural identity, but rather write in multiple non-English languages as part of a feminist knowledge project that challenges the dominance of English as a lingua franca and in so doing creates estrangement from western humanistic philosophical systems. While each writer’s works have received much critical recognition, to date their use of multiple non-English languages across their corpuses remains one of the most striking yet under-theorized aspects of their writings.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: A Novel Filtering Approach in Visual Odometry for Autonomous Ground Vehicles Application

contributor:
Kirubarajan, Thia
Electrical and Computer Engineering

abstract:
A monocular Visual Odometry system has been developed and tested on different
datasets and the outputs have been compared with the available ground truth information
to analyze the precision of the system. This system is capable of estimating
the 3D position of a ground vehicle robustly and in real time.
One of the main challenges of monocular VO is the ambiguity of the scale estimation
which is addressed by assuming that the ground is locally planar and the height
of the mounted camera from the ground is fi xed and known.
In order to improve the VO estimation and to help other stages of VO process an
effective fi ltering approach is utilized. It is shown that an IMM fi ltering can address
the needs of this speci c application, as the movement of a ground vehicle, is different
depending on different scenarios.
The results of simulation on the well-known KITTI dataset demonstrates that
our system's accuracy improved compared to what is considered to be one of the best
state-of-the-art monocular Visual Odometry system.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: In A World Where Climate Change Is Everything...; Conceptualizing Climate Activism And Exploring the People’s Climate Movement

title: CLIMATE CHANGE ACTIVISM AND THE PEOPLE’S CLIMATE MOVEMENT

contributor:
Rethmann, Petra
Anthropology

abstract: This thesis explores the strategies and imaginations of activists working to inspire action on climate change. It is based on my ethnographic fieldwork with the Toronto People’s Climate Movement as well as my own experiences as an activist living and working in Toronto. In conceptualizing climate activists anthropologically, I understand social movement actors as connected by shared imaginations rooted in universalizing scientific discourses and defined by deeply-held concerns for climate change and the motivation to take action. I devise an explanatory schema for the climate movement based on the “code-sort” method that shows how the strategies of climate activists are informed by four key values: crisis mitigation, social change, collective organizing and individual agency. These values converge in different iterations to inspire a variety of activist strategies and imaginations. Some are about getting climate change onto the public agenda and emphasize the urgent need for top-down solutions to reduce emissions. Others work to factor personal autonomy and well-being into their goals and methods, taking as their starting point the understanding that, for solutions to climate change to be adopted by society at large, they must consider the needs of both people and the environment in their designs of sustainable systems. To begin to understand “how climate change comes to matter” (Callison 2014) demands that we venture into a different world; a world in which the threat of ecological catastrophe is not the elephant in the room but the guiding lens of every conversation; in which subject matter avoided in polite society is the focus of every planning meeting, potluck and PowerPoint presentation; in which the not-so-novel question of how to live a moral life meets the far-more-recent dilemma of how to live one that is also sustainable. In the imaginations of those who inhabit this world, climate change is everything.

abstract: Thesis

abstract: Master of Arts (MA)

abstract: This thesis explores the strategies and imaginations of activists working to inspire action on climate change and considers different anthropological approaches to conceptualizing activism and social movements in the contemporary moment. I use the framework of a "social imagination" as a way to account for the connections between activists and social movement actors that cannot be explained by the concepts of "culture" and "community." I then situate climate activism as a social movement based on four key principles: crisis mitigation, social change, collective organizing and individual agency. This research is based on ethnographic fieldwork with the Toronto People’s Climate Movement and ends with a consideration of how this particular group of activists is working to address climate change at a community level through strategies that take personal autonomy, civic engagement and well-being as the starting point for sustainable societies.


title: Investigating the Generation of Biophotons Induced by Low-Dose Beta-Irradiation and their Role in the Radiation-Induced Bystander Effect

contributor: Radiation Sciences (Medical Physics/Radiation Biology)

subject:
Biophoton
Radiation
Ionizing
Beta
Bystander Effect
Radiation-Induced Bystander Effect
Ionizing Radiation
Cell Signalling

abstract:
The communication of information between irradiated and non-irradiated bystander cell populations and the subsequent expression of radiation-like responses in the non-irradiated population, formally referred to as the radiation-induced bystander effect, is a very well established phenomenon in the study of radiobiology. Intercellular communication of bystander signals is known to occur via the exchange of soluble factors through biological fluids and via the transfer of molecules between adjacent cells via gap-junctions. Both of these communication methods require some degree of physical contact between biological entities. However, observations made in the literature demonstrating the induction of radiation effects in optically-coupled, yet chemically-separated organisms raises the hypothesis that alternative radiation bystander communication mechanisms may exist that have not yet been explored. Following the detection of significant photon emission from human keratinocyte cells
exposed to ionizing beta-radiation by Ahmad in 2013, the involvement of an electromagnetic bystander signal was proposed. While not yet established in the field of radiobiology, intercellular communication via electromagnetic signalling is widely studied in the field of biophotonics. The emission of electromagnetic radiation from biological material, called biophoton emission, and the subsequent communication of effects using those signals has been characterized both spontaneously and as a result of perturbation by various stressors. This thesis therefore aimed to investigate intercellular communication via electromagnetic signalling stimulated by low-dose ionizing radiation to identify a possible convergence between the fields of biophoton communication and radiation-induced bystander effects. The characterization of biophoton emission from human cell cultures was accomplished using a single photon counting photomultiplier tube. The results revealed that biophoton emission is exacerbated by external stimulation (beta-radiation), it possesses a dependence upon the activity of radiation delivered, the density of the irradiated cell culture, and cell viability. These results suggest that biophoton emission is governed by physical transitions between excited and ground states and may further be modulated by metabolic processes. An effect of beta-radiation-induced biophoton emission upon non-irradiated bystander cells was identified and manifested as a reduction in cell survival. The modulatory effects observed following the application of photomodulating agents to the bystander cultures support ultraviolet electromagnetic radiation as a responsible factor in the communication of bystander signals. Observation of photon emission across the entire ultraviolet, visible and infrared spectra lead to the suggestion that ultraviolet wavelengths are only a portion of the signal responsible for eliciting bystander responses and that coherent interaction of multiple wavelengths is probable in the intercellular exchange of information. The possibility of a link between biophoton bystander signalling and soluble factor mediated bystander effects was investigated next by isolating exosomes from biophoton-exposed bystander cultures. Positive bystander responses were exhibited by secondary reporter cells incubated with the exosomes isolated from the biophoton-exposed bystander cultures, thereby suggesting that biophoton signalling is a possible form of biological redundancy where it acts as an intermediary to trigger soluble factor release and further reinforce intercellular communication. Finally, the effect of beta-radiation-induced biophoton signals upon mitochondrial activity was assessed and revealed the capacity for biophotons to downregulate Complex I and ATP synthase activity. The demonstrated effect of biophotons upon mitochondria elucidates a candidate mechanism worthy of further exploration to determine how biophotons may trigger responses in bystander cells. Overall, this thesis elucidates an additional mechanism for intercellular communication between biological systems perturbed by low doses of ionizing radiation, in the form of an electromagnetic signal. This work contributes to the current perspective on biophoton bystander signalling as a potential source of biological redundancy, facilitating a means of intercellular communication when optical coupling but not chemical contact is available in a given system.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: “If Not Me, Then Who?” The Narratives of Medical Aid in Dying (MAiD) Providers and Supporters Around Their Professional Identity and Role in MAiD

contributor:
Badone, Ellen
Anthropology

subject:
medical aid in dying
euthanasia
professional identity
health care providers

abstract:
Medical Assistance in Dying (MAiD) became legally accessible to Canadians in 2016, bringing with it significant changes to the Canadian health care landscape. With legalization of MAiD, physicians, nurses and allied health care workers had to consider their own systems of values, beliefs and their professional identity and decide whether or not they would be able to contribute to this practice or participate actively in this new medical procedure.
I argue that health care professionals who participate in this practice create a professional identity that is intrinsically bound to the ethics and practice of MAiD, thus making it permissible for them to support and participate in the procedure actively. Moreover, I argue that this system of morals and beliefs has been accrued by these health care professionals across experiences and time that contribute to their capacity to participate in MAiD.
Hamilton Health Sciences (HHS) was the locus for this research. HHS encompasses a network of five hospitals in the Hamilton, Ontario area. Each hospital region in Ontario has a unique staff and values, and HHS is no exception. HHS houses the Assisted Dying Resource and Assessment Service (ADRAS) group, a team of uniquely skilled MAiD providers, assessors and health professionals who service the HHS patient community. It is this group that is at the center of this research. Through interviews with members of ADRAS, I determined that values of altruism, belief in self-determination and deep respect for patients and families are central to the individual and collective identities of this group. In light of this ethical stance, members of ADRAS have crafted complex professional identities both individually and as a collective that enable them to participate in MAiD in a complete and meaningful way.

abstract: Thesis

abstract: Master of Arts (MA)


title: A comprehensive approach to health literacy: validating the All Aspects of Health Literacy Scale in a respresentative sample of Arabic-speaking adult Syrian refugees

contributor:
Newbold, Bruce
Global Health

subject: health literacy, Syrian refugee, AAHLS, functional health literacy, communicative health literacy, critical health literacy, Canada

abstract:
MASTER OF SCIENCE (2017), McMaster University, Hamilton ON (Department of Global Health)
TITLE: A comprehensive approach to health literacy: validating the all aspects of health literacy scale (AAHLS) in a representative sample of Arabic-speaking adult Syrian refugees
AUTHOR: 		Raafia Siddiqui, BSc Hons. (York University, 2014)
SUPERVISOR: 	Dr. K. Bruce Newbold
NUMBER OF PAGES: vii, 92

abstract: The purpose of this study is to quantify current health literacy levels amongst a segment of the Syrian refugee population in Canada by translating and validating an existing comprehensive health literacy assessment tool, the All Aspects of Health Literacy Scale (AAHLS) into Arabic. This study (1) determined functional, communicative and critical health literacy levels amongst Syrian refugees. Functional and critical health literacy was comparatively low but respondents seemed able to effectively communicate with their providers and access supports to read and fill in health documents. Significant correlates of low health literacy were presence of long-term health conditions and place of origin (country versus refugee camp). This study also validated the AAHLS in Arabic-speaking Syrian refugees, with a Cronbach’s alpha of 0.67 for the overall scale and 0.63 for health literacy items. The overall scale had high content validity. The feasibility of this instrument as a self-administered screening tool in clinical or community settings was demonstrated with a high response rate of 0.86.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: Health literacy looks at an individual's ability to read, understand and interpret health information and ultimately use it to exert greater control over their health. The purpose of this study is to understand the factors that influence health literacy levels amongst a segment of the Syrian refugee population in Canada by translating and validating an existing comprehensive health literacy assessment tool, the All Aspects of Health Literacy Scale (AAHLS) into Arabic. This study (1) determined functional (reading and filling in health documents), communicative (speaking to health providers) and critical health (assessing the relevance and appropriateness of health information) literacy levels amongst Syrian refugees. Functional and critical health literacy was comparatively low but respondents seemed able to effectively communicate with their providers and access supports to read and fill in health documents.  Low health literacy was associated with having a long-term health conditions and staying in a refugee camp. This study found the translated AAHLS to be reliable, with a Cronbach’s alpha of 0.67 for the overall scale and 0.63 for health literacy items. The overall scale had high content validity. The feasibility of this instrument as a self-administered screening tool in clinical or community settings was demonstrated with a high response rate of 0.86.


title: Caregiver psychosocial wellbeing and family violence: A scoping review of factors that affect the wellbeing of children in humanitarian crisis

contributor:
Wahoush, Olive
Global Health

subject:
Humanitarian crisis
Psychosocial wellbeing

abstract:
Background: Children make up more than 50% of the population affected by humanitarian crisis. Although it has been shown that a stable, nurturing and safe home environment can help mitigate the negative effects of ambient violence and instability, with deteriorating family relationships and poor psychosocial wellbeing of caregivers in humanitarian crisis, children may face an additional source of harm from within their home. This scoping review was conducted to a) examine the extent to which caregiver psychosocial wellbeing and family violence affect the wellbeing of children and b) understand if interventions and programming can improve wellbeing of children through changes in caregiver psychosocial wellbeing or family violence.
Methodology: Using the Arksey and O’Malley framework, we searched three electronic databases and various grey literature sources for literature that discussed the associations between caregiver psychosocial wellbeing and/or family violence, and the wellbeing of children. A quantitative and thematic analysis was conducted to examine the extent, range and scope of literature.
Results: The findings from 22 identified observational studies indicated that caregiver psychosocial wellbeing and family violence are both associated with various dimensions of child wellbeing. Although the three interventional studies suggest that targeting caregiver wellbeing and family violence may be promising, the search revealed very limited evidence in the form of evaluated programs that reliably measure caregiver and family dimensions, while also measuring child outcomes.
Conclusion: Focusing on improving the wellbeing of caregivers and reducing family violence may provide an important venue through which we can improve the lives of children. However, further research must be conducted to expand our understanding of the relationships between relevant factors, and to create robust program evaluations to determine the efficacy and value of interventions. Such research can contribute to the evidence base that is crucial to helping us protect and promote the wellbeing of children in these challenging contexts.

abstract: Thesis

abstract: Master of Science (MSc)


title: “VILLAIN” VS. “VICTIM”: A NEWS HEADLINE ANALYSIS AND LITERATURE REVIEW OF CANADIAN NEWS PRINT MEDIA IN REPRESENTING REFUGEES AND FRAMING CANADIAN PERCEPTIONS OF REFUGEES

title: “VILLAIN” VERSUS “VICTIM”: A NEWS HEADLINE ANALYSIS AND LITERATURE REVIEW

contributor:
Wahoush, Olive
Banfield, Laura
Global Health

subject:
refugee
media
newsprint
representation
headline
canada
literature review
public perception

abstract: An unprecedented 65.6 million people around the world have been forcibly displaced from their homes; 22.5 million of these individuals are refugees and 10 million are considered stateless (UNHCR, 2016a). Although, the conflict in the Syrian Arab Republic and the large arrival of asylum-seekers at the European borders in 2015 and 2016 gained significant global media attention, the frequently interchangeable use of the terms “migrant” and “refugee” to describe population within news headlines imposes significant implications on the legal protections entitled to each label. Conflating refugees and migrants can undermine public support for refugees and the asylum system at a time when there are more refugees than at any previously recorded time (UNHCR, 2016a). To better understand, two electronic databases CBCA Reference and Current Events and Canadian Periodical Index were searched for headlines containing the key term “refugee(s)” in Canadian English language newspapers. A total of 94 words were identified that offered an indication of the portrayal of refugees in the news media. Fourteen words were categorized as positive, 56 words were negative and 25 words were identified as neutral In addition, a literature review was conducted mirroring the five-stage Arksey and O’Malley (2005) scoping review framework and a data charting form was used to extract descriptive themes. Seven electronic databases (Sociology, Social Sciences Abstract, Web of Science, Communication Source, JSTOR and Social Work) were searched.. A total of 32 studies were selected for the literature review (16 through the database search and 16 through reference list search). From the included literature, five descriptive themes were found: securitization, immigration, legitimacy, economic considerations and othering. Both analyses indicated a dominant securitized discourse that portrays refugees negatively as a threat to the state and revealed a decrease in humanitarian dialogue within news media coverage. Positive representations of refugees were limited to the narrative of a passive victim or contributors to the economy. In addition, refugee voices within news media were restricted to their expression of gratitude towards the state and their compassion. The lack of refugee perspective and the use of journalistic semantic strategies perpetuate a one-sided negative portrayal of refugees. A more balanced media narrative is required to ensure that refugees are being portrayed accurately and their voices are heard.

abstract: Thesis

abstract: Master of Science (MSc)


title: AN EXAMINATION OF SEDIMENT MANAGEMENT PROCESSES IN THE GREAT LAKES AND THE USE OF A DECISION SUPPORT SYSTEM (DSS) FRAMEWORK FOR SEDIMENT REMEDIATION PROJECTS

contributor:
Krantzberg, Gail
Geography and Earth Sciences

subject: Sediment Remediation

subject: Decision Support System

subject: Great Lakes Areas of Concern

subject: Environmental Decision-Making

subject: Public Engagement

abstract:
Great Lakes Areas of Concern (AOC) are designated geographical locations within the Great Lakes Basin with particularly degraded environmental conditions. There is a consensus among diverse sectors in the Great Lakes Basin that contaminated sediment is a major environmental problem and a key factor in many of the impairments of the human and nonhuman uses (beneficial uses) of the Great Lakes.  This case study examines Randle Reef in the Hamilton Harbour (AOC) which is the largest Canadian contaminated sediment site in the Great Lakes containing 695,000 m3 of sediment contaminated with polycyclic aromatic hydrocarbons (PAH) and metals. The cleanup of the Randle Reef site is a major step in the process to restore Hamilton Harbour and remove it from the list of AOCs. The Randle Reef sediment remediation project is finally coming to fruition after more than thirty years of study, discussion, collaborations, and debate.
As in the case of Randle Reef, environmental decisions are often complex and multi-faceted and involve many stakeholders with competing (sometimes conflicting) priorities or objectives representing exactly the type of problem that humans are poorly equipped to solve unaided. When professionals encounter complex issues, they often attempt to use approaches that simplify the complexity so that they can manage the problem at hand. During this process, valuable information may be lost, opposite points of view may be ignored and elements of uncertainty may be overlooked. A systematic methodology that combines both quantitative and qualitative data from scientific or engineering studies of risk, cost, and benefit, as well as stakeholder objectives and values to rank project alternatives, has yet to be fully developed for contaminated sediment decision-making.
The main goal of this Ph.D. research was to develop a Decision Support System (DSS) framework to aid the complex decision-making in sediment remediation. The proposed DSS framework incorporates the five key themes that, through research, were found to be the most relevant for sediment remediation projects. These themes are 1)participation of appropriate actors with common objectives; 2)funding and resources; 3)decision-making process; 4)research and technology development; and 5)public and political support. There was a need to gather relevant information and data from various sources to develop the required DSS framework. For this purpose, expert interviews were conducted, responses were collected through a public survey, Qualitative Document Analysis (QDA) was performed on available policy and research documents, and a review was undertaken of how other jurisdictions have employed DSS to aid their decision-making process. The final DSS framework has six key components as follows: 1)data module; 2)communication module; 3)document module; 4)knowledge module; 5)tools module; and 6)DSS optimization module. This generic framework can assist practitioners in developing more systematic and structured decisions for sediment remediation by incorporating an Integrated Information Management System (IIMS) along with a DSS optimization module. This IIMS+DSS method can aid the decision-making process by making it documented, reproducible, robust, transparent and provide a coherent framework to explore and analyze available alternatives in an attempt to reach the preferred solution promptly.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Advances in Sintering of Powder Metallurgy Steels

contributor:
Malakhov, Dmitri Vladimirovich
Materials Engineering

subject:
Powder Metallurgy
Ferrous
Homogenization
Alloying Additions
DICTRA
Wavelength Dispersive Spectroscopy

abstract:
In comparison to traditionally fabricated steels that can undergo extensive processing to produce a complex-shaped component, the powder metallurgy (PM) technique can provide a more efficient approach as it is capable of producing intricately-shaped components that require little to no additional processing and machining [1], [2]. A key factor in being able to do so pertains to quenching and utilizing an appropriate quenching agent that can provide dimensional stability to the part being quenched [3], [4]. To ensure that a PM component can perform equally well when being quenched by a quenchant of reduced cooling capability, the PM component should be if not more, then just as hardenable. Steel hardenability can inevitably be improved with the increase of overall alloying content [5], however, if overall alloying content is to be kept at a minimum, the concept of lean PM steel design is one worth investigating; where a lean steel entails that each and every alloying addition is utilized to its maximum potential.

This study evaluates the homogenization behaviour of alloying elements in PM steels during sintering as well as the efficiency of wide-spread industrial practices involving the use of various master alloys and ferroalloys, and investigates the realm of liquid phase sintering to understand and optimize the homogenization behaviour of alloying elements and mechanical properties of PM steels. In the context of this work, multi-component master alloys contain at least three of non-ferrous metals as alloying elements and ferroalloys are master alloys containing iron in addition to typically a maximum of two other non-ferrous alloying additions.  Part one of this study discusses a combination of thermodynamic software (DICTRA and Thermo-Calc), incremental sintering experiments and scanning electron microscopy (SEM) - wavelength dispersive spectroscopy (WDS) that were used in order to form a deeper understanding of the homogenization behaviour of alloying elements within PM steel during sintering. Electron microscopy analyses on partially and industrially sintered components provide elemental maps to track the evolution of alloying elements as they relax to homogeneity. Electron microscopy analyses for this portion of the study were conducted on an industryproduced automotive component that was sectioned and sintered industrially as well as experimentally at 1280°C for 30 minutes and 13.4 hours.

DICTRA simulations carried out for this research provide a 1-D insight into the evolution of concentration profiles and phases throughout various sintering times for  systems involving Cr, Mn, C and Fe. DICTRA simulation results of alloying sources were studied alongside alloying element profiles obtained by compiling point quantification from wavelength dispersive spectroscopy maps for the sintered automotive component. Computational results provided conservative, semi-quantitative recommendations on optimal alloy addition forms that lead to an improvement in homogenization.  Part two of this study involves the approach of fabricating and testing multi-component master alloy additions. As these materials are widely employed in PM and are typically fabricated by solidification, their states are non-equilibrium and therefore have regions containing phases precipitating in the beginning of freezing which have higher melting temperatures than regions with phases forming later on. During heating, it is hypothesized that Scheil’s solidification path backtracks and as a result, a fraction of liquid in the ferroalloy can be estimated at sintering temperature. If the fraction is significant, the utilization of this ferroalloy implies liquid phase sintering. Through a combination of Thermo-Calc and Fortran softwares, multi-component ferroalloys with promising compositions were discovered in Fe-C-Cr-Mn, Fe-C-Cr-Mn-Ni, FeC-Mn-Mo, Fe-C-Mn-Mo-Ni and Fe-C-Cr-Mn-Mo-Ni systems for low temperature liquid phase sintering. Those of the Fe-C-Cr-Mn-Mo, Fe-C-Cr-Mn-Mo-Ni and Fe-Mn-Mo-Ni system were fabricated and tried in practice. Compositional maps and mechanical properties of PM steels made with variations of this specially tailored multi-component master alloys were compared with those for which traditional alloy additions were used.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Analysis of On/Off servers with Dynamic Voltage Scaling

contributor:
Down, Douglas
Computing and Software

subject: green computing, performance, DVS

abstract: With rapid adoption of cloud solutions across industries, energy consumed by server farms continues to rise. There are numerous approaches to reduce energy consumption in data centres, and one of the approaches is to use energy-aware policies, which focus on how servers should be operated in order to achieve energy saving and meet service level agreements (SLA). In this thesis, we focus on studying a single server model with dynamic voltage scaling (DVS), presenting a framework with explicit solutions to solve for performance metrics and energy consumption. Our framework is convenient and in- tuitive, one can easily identify expected response time and expected energy consumption for a given policy. In addition, we also provide insights on how the value of the faster service rate and the choice of when to use speed scaling impact energy consumption and performance metrics.

abstract: Thesis

abstract: Master of Computer Science (MCS)


title: Accessory glands and sperm competition

contributor:
Balshine, Sigal
Psychology

subject:
sperm
sperm competition
fish biology
fish physiology
alternative reproductive tactics
seminal fluid
accessory gland
plainfin midshipman
toadfish
seminal vesicle
sperm energetics
sperm morphology

abstract: Sperm competition is a widely-recognized and powerful selective force. Male accessory glands are organs found across animal taxa that can influence sperm performance, and thus may be selected for in competitive contexts. In fishes, these organs are in fact rare, but display great diversity in form and function across species. Although the accessory gland is known to play a role in mate attraction, parental care, fertilization, or post-copulatory competition in a few select species, the role of this organ remains a mystery in most species. Many fishes with accessory glands also exhibit alternative reproductive tactics (ARTs), which add an extra layer of complexity to how species respond to sperm competition. Because males of different ARTs typically experience different levels of sperm competition risk, it’s possible they may differentially invest in accessory glands to overcome this competition. In this thesis, I used the plainfin midshipman fish (Porichthys notatus), a species with both ARTs and an accessory gland, to experimentally investigate the role of the accessory gland in sperm competition and uncover how this organ may differ between ARTs. Over a two-year period, I studied tactic-specific investment in the accessory gland in fish from the beaches of British Columbia. I also examined the effects of seminal fluid, produced in part by the accessory gland, on sperm performance and morphology. I found that males adopting the ‘guarder’ male tactic invested more in one region (the lobules) of this organ, while males adopting the smaller ‘sneaker’ male tactic invested more the other region of the gland (the nodes). Using data collected over five years, I found that guarder males also invested more in their whole accessory glands. Additionally, I report that sperm swam faster in the presence of seminal fluid, and seminal fluid increased sperm head size in both male tactics and increased midpiece size in guarder males. These results suggest that the plainfin midshipman accessory gland may have dual functions, one of which may be to aid sperm competitive ability through enhancements in swimming speed and potentially more successful sperm morphology. Taken together, the results of my thesis improve our knowledge of the role of non-sperm components like seminal fluid and the accessory gland in sperm competition, and demonstrate how species with ARTs can have varying physiological responses to such competition. Only a handful of studies have considered the effects of seminal fluid on sperm performance. By examining sperm competition in a more biologically relevant way and incorporating the effects of a little-studied organ that impacts sperm competition, we should be able to more generally and accurately appreciate the dynamics of post-copulatory competition and fertilization.

abstract: Thesis

abstract: Master of Science (MSc)


title: Surviving the International Experience: Exploring the Mental Health of Graduate International Students

contributor:
Carranza, Mirna Jr
Social Work

subject:
International students
Mental health
acculturation

abstract:
This qualitative research examines graduate international students’ experiences, in particular, their mental health during their acculturation process to McMaster University. This study specifically investigates the challenges graduate international students encounter while pursuing their studies, how these challenges impact their mental health, and the strategies they develop to manage these challenges. Drawing from the findings, policy recommendations are provided for relevant school stakeholders, and implications for theorists to consider as they relate to international students’ mental health in their particular social identity are presented as well.
This research study is organized under a critical framework. Critical theory (CT) is mainly used to do data analysis and to generate knowledge about graduate international students’ mental health as well as reveal the hidden structures of their experience. Individual, semi-structured interviews were conducted with six graduate international students from different departments, countries, ages, and genders, to examine a variety of interpretations of the graduate international student experience at McMaster. Key themes, including challenges encountered as international students, conceptualizing mental health, and factors affecting their mental health struggles, are also discussed.

abstract: Thesis

abstract: Master of Social Work (MSW)


title: LIME PLASTER USE AT LATE BRONZE AGE KALAVASOS-AYIOS DHIMITRIOS (CYPRUS): EVIDENCE FOR APPLICATION-SPECIFIC RECIPES AND THE CREATION OF SOCIAL SPACE

contributor:
Carter, Tristan
Anthropology

subject:
urbanization
social space
place
social interaction
construction traditions
practice
plaster
technology
Cyprus
Late Bronze Age
micromorphology
FT-IR

abstract:
Kalavasos-Ayios Dhimitrios (K-AD; Figure 1) is a Late Bronze Age (LBA) settlement on Cyprus. It is notable for having among the earliest examples of urbanism and monumental architecture on the island along side the sites of, for example, Kition, Alassa, Enkomi, and Maroni (Philokyprou 2011; Fisher et al. in press). The LBA on Cyprus marked the beginning of urban society, economy and architecture in Cyprus (Fisher et al. in press). This study explores the social processes associated with the transition to urbanism represented by the entangled relationship between the architectural creation of social spaces and the use of these spaces as platforms for the creation and negotiation of power and influence (Fisher 2009a, 2009b; Fisher et al. in press). Specifically this study will concentrate on the construction of plaster surfaces, the immobile architecture of these social spaces, as indexes of the social development at K-AD during the LBA.
	Analysis of pyrogenic lime and gypsum plasters was carried out using high-resolution microscopic methods based on the integration of petrography and soil micromorphology. These techniques are employed to optically examine in-situ and oriented plaster samples in laboratory thin section. Laboratory Fourier-transform infrared spectroscopy (FT-IR) analysis was applied to loose sediments to obtain spectroscopic data when necessary.
	Following the findings that lime plaster recipe variation is the result of human choice (Kingery et al. 1988; Love 2011, 2013a) the results of this analysis shows that the LBA architects at K-AD produced different recipes for different utilitarian uses and also that the construction of elite spaces demanded complex recipes that extend beyond utilitarian requirements, which can be classified as more “expensive,” resource-draining procedures (Kingery et al. 1988; Love 2011). Plaster is used at K-AD for both functional purposes and as an active component in societal creation and transformation.

abstract: Thesis

abstract: Master of Arts (MA)

abstract: Craft specialization is a core feature of urban life but the process of specialization is not perfectly understood. This thesis seeks to explore the use of lime plaster for constructing surfaces at the Late Bronze Age (LBA) site of Kalavasos-Ayios Dhimitrios (K-AD) on the island of Cyprus. Previous research has revealed a central, monumental complex, among the first of its kind on the island, surrounded by an early city. How did the LBA people create their living environment in this new setting? This thesis has shown, through the analysis of lime plaster features, floors and walls that the LBA inhabitants of K-AD were able to create diverse, specialized surfaces with a specialized lime plaster tradition in a scale and complexity that went beyond structural requirements, suggesting these surfaces were constructed with the explicit intent for creating space imbued with social meaning.


title: A ROLE FOR BACTERIAL-DERIVED PROTEASES AND PROTEASE INHIBITORS IN FOOD SENSITIVITY.

contributor:
Verdu, Elena
Medical Sciences

abstract:
Celiac disease is a chronic atrophic enteropathy triggered by the ingestion of
dietary gluten in genetically predisposed individuals expressing HLA class II genes, DQ2
or DQ8. Both innate and adaptive immune mechanisms are required for the development
of the disease. The adaptive immune response is well characterized and includes the
development of gluten-specific T-cells and antibodies towards gluten and the autoantigen,
tissue transglutaminase 2. Less is known about the initiation of the innate immune
response and its triggers, which is characterized by increases in cytokines such as IL-15,
leading to proliferation and cytotoxic transformation of intraepithelial lymphocytes that
are not specific to gluten. Although genetic susceptibility is necessary for celiac disease
and present in 30% of most populations, only about 1% will develop it. This points to
additional environmental factors, which could be microbial in origin. Disruptions of the
gut microbial ecosystem, termed the intestinal microbiota, have been associated with the
development and severity of many gastrointestinal disorders. Indeed, compositional
differences in fecal and small intestinal microbiota have been described in patients with
active celiac disease compared to healthy controls. This “dysbiosis” includes increases in
small intestinal Proteobacteria and reductions in Firmicutes, but mechanistic information
is lacking. Our lab has previously demonstrated that patients with active celiac disease
have decreased expression of the serine protease inhibitor elafin in the duodenal mucosa,
suggesting that proteolytic imbalance from either host or microbial origin, could be
important in disease pathogenesis. The aim of this thesis is to study mechanisms through
which the intestinal microbiota may contribute to the development of gluten sensitivity. I thus hypothesized that the proteolytic capacity of a dysbiotic small intestinal microbiota
could promote the development of gluten sensitivity, in a genetically susceptible host.
Firstly, I investigated whether the intestinal microbiota is a source of proteases in the gut
lumen, that metabolize gluten in vivo affecting its immunogenicity. Secondly, I studied
whether and how bacterial proteases stimulate innate immune mechanisms, relevant to
celiac disease pathogenesis. Last, I investigated whether some of these mechanisms could
be targeted to improve gluten sensitivity.
In Chapter 3 of this thesis, I show that the small intestinal microbiota participates
in gluten metabolism in vivo in mice. Proteobacteria and opportunistic pathogen
Pseudomonas aeruginosa, isolated from patients with celiac disease, metabolize gluten
proteins through microbial elastase. Bacterially-modified gluten peptides translocate the
mucosal barrier with efficiency and retain immunostimulatory capacity when incubated
with gluten-specific T-cells from patients with celiac disease. However, bacteria found in
higher abundance in healthy individuals, such as Lactobacilli, metabolize P. aeruginosa modified gluten peptides reducing their antigenicity. This constitutes an opportunistic
pathogen-gluten-host mechanism that could modulate celiac disease risk in genetically
susceptible people.
In Chapter 4, I show that bacterial proteases capable of extracellularly
metabolizing gluten, such as P. aeruginosa elastase, also have the capacity to stimulate
innate immune responses in the small intestine, likely through a protease activated
receptor-2-dependent mechanism. This innate immune response does not require HLArisk
genes and is characterized by non-specific increases in small intestinal intraepithelial lymphocytes. In mice transgenic for the HLA-DQ8 gene, the presence of P. aeruginosa
elastase in the small intestine exacerbates gluten-induced pathology.
In Chapter 5, I use a commensal Bifidobacterium longum strain that naturally
produces a serine protease inhibitor, with the ability to inhibit elastase activity. I show
that administration of Bifidobacterium longum to mice expressing the HLA-DQ8 gene
prevents gluten immunopathology. The effect is dependent on the production of the
bacterial serine protease inhibitor, as it was not observed with a B. longum knock-out for
the serine protease inhibitor gene. Within this thesis, I demonstrate that microbial
proteases can modulate gluten sensitivity through participation in both adaptive and
innate immune pathways using celiac disease as a model of gastrointestinal disease.
Further, I provide pre-clinical support that this pathway can be targeted for therapeutic
purposes using protease inhibitors from commensal bacterial strains. My results provide
causal evidence and novel mechanisms through which small intestinal bacteria may
exacerbate or attenuate gluten sensitivity.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Rearrangement of 2D clusters of droplets under compression: from crystal to glass

contributor:
Dalnoki-Veress, Kari
Physics and Astronomy

subject:
Soft-Matter
Emulsion
Crystal-to-glass
Micropipette deflection

abstract:
Emulsions and colloidal suspensions have various industrial applications but are also used in laboratories as model systems for studying the different phases of matter. They are versatile as their nature, size and inter-particle interactions are easily tuneable. These systems are perfect for studying questions such as the phase transition. In this thesis, we investigate the transition from an ordered crystal to a disordered glass. Perfectly ordered crystals are modeled by clusters of highly monodisperse droplets. We study the transition toward a glassy system by mixing two monodisperse populations of droplets in different proportions. The clusters are compressed between two thin glass rods, one of which is a force transducer. The forces within the clusters are directly measured and used as an indicator of the composition of the cluster. Upon introduction of disorder, the number of peaks in the force measurement increases drastically. We find that the way the energy is dissipated in the cluster is valuable information to characterize the crystal-to-glass transition.

In addition to the experimental study of the crystal-to-glass transition, we have developed an analytical model that is in full agreement with the experimental observations. A crystal is modeled as an assembly of Hookean springs that will store elastic energy until it reaches a fracture point. We are able to predict the number of peaks in the force measurements when defects are introduced using simple geometric arguments. From this prediction, the way the work is dissipated in a given transition can be predicted.

abstract: Thesis

abstract: Master of Science (MSc)


title: Effects of Self-Control Exertion on Mental Fatigue and Perceived Exertion during Whole-Body Exercise

contributor:
Bray, Steven, R.
Kinesiology

subject:
Self-control
Self-regulation
Thought-suppression
Mental Fatigue
Cardiovascular Exercise
Whole-body Exercise
Depletion

abstract: Self-control exertion leads to performance decrements during tasks demanding of muscular and cardiovascular systems (Bray et al., 2008; Marcora et al., 2009). Several reviews have also implicated self-control depletion with the psychobiological state of fatigue (Hagger et al., 2010; Van Cutsem et al., 2017). In this state, individuals have also been noted to report higher levels of perceived exertion when exercising at vigorous intensities (MacMahon et al., 2014; Marcora et al., 2009; Wagstaff et al., 2014). The purpose of this study was to investigate physical performance and ratings of perceived exertion during a self-paced maximum distance cycling trial (MDT) following a short bout of mentally-fatiguing cognitive activity (thought-suppression). Recreationally active participants (N = 16, Mage = 20.94) completed one familiarization session and two testing sessions. All visits were separated by ≥ 72-hours. Control and experimental trials were counterbalanced, with either a 6-minute bout of thought-logging (control) or a 6-minute bout of thought-suppression (experimental) being performed prior to each respective MDT. Ratings of perceived exertion (RPE) were solicited from participants across three sensory domains relevant to MDT task performance (Leg-muscle, Respiration, Mental). Thought-suppression was perceived to be significantly more demanding than the control task, which resulted in significantly higher ratings of mental fatigue (p = 0.04, 2 = 0.26). Distance travelled on the MDT was not significantly different following thought suppression, relative to control trials (p = 0.84, 2 = 0.00). Similarly, a repeated-measures ANOVA showed no differences in HR between conditions (p = 0.95, 2 = 0.00). Despite these similarities, ratings of perceived leg-muscle exertion (RPE-L) were significantly higher during the MDT following thought-suppression (p = 0.05, 2 = 0.24). RPE-R (respiration) and RPE-M (mental) ratings also trended towards higher scores following the experimental manipulation, although they did not differ significantly. RPE-L was perceived to be significantly higher than both RPE-R and RPE-M in both conditions on the MDT (ps < 0.05). RPE-M was rated significantly lower than RPE-L and RPE-R during MDTs in both conditions (ps < 0.05). Results indicate that performing a demanding self-control exertion task for a short duration leads to increased feelings of mental fatigue. The observed levels of fatigue were also associated with higher than normal ratings of perceived exertion during cycling tasks of equal demands and performance.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: Any thought, emotion or behaviour that an individual modifies in order to better suit their goals occurs as a result of self-control exertion. Research indicates that just like the exertion of muscular strength, exerting self-control impacts subsequent attempts to do so. Using a mentally-demanding task, we induced states of self-control depletion which left individuals feeling mentally-fatigued. As a result of this state, participants needed to exert themselves harder in order to complete a task that was perceived less demanding, when non-fatigued.


title: Product Performance and Contracts in Multi-component System Industries: Theory and Evidence

contributor:
Ray, Sourav
Business

subject: Product Performance Contract, Multi-Component Systems, Governance, Interfirm Relationships

abstract:
This dissertation will investigate how Product Performance Contracts are organized in Multi Component Systems contexts that proliferate contemporary OEM industries.  The last two decades have seen a big change in both practice as well as the product engineering technologies that form the ecosystem within which suppliers and buyers negotiate the scale and scope of their transaction contracts.  While we have seen the focus of industrial procurement move from specifications based contracts to performance based contracts, we are also witnessing a burgeoning technological capability that allows remote monitoring of product performance.  These capabilities are part of the interconnectivity driving the much-touted Internet of Things (IoT) technology and at the heart of the Industrial Big Data ecosystem.  The dissertation will attempt to explain three major phenomena in the industrial buyer and seller relationship in the context of Multi Component System Industries.
First, we uncover the factors that explain the choice of product performance contract specificity between the OEM and suppliers. We first set up an analytical model to explain the notion of an optimal contract specificity level and predict and further empirically test the role of different factors in the choice of contract specificity. We find that while the technology uncertainty decreases the level of optimal contract specificity, OEM’s transaction specific investment, unconstrained mixing-and-matching of branded component, and extent of product monitoring technology increases the level of optimal contract specificity.
Second, we provide empirical evidence that any deviation from optimal contract specificity erodes value in the form of an increase in total transaction cost. In our transaction cost efficiency model, we also illustrate with a precise granularity that under-specified contracts lead to more ex-post dispute costs, and over-specified contracts lead to more ex-post contract monitoring cost and ex-ante contract writing cost.
Third, we investigate how contracts, investments in strategic capabilities such as monitoring technology, the overall firm strategy, and transaction costs determine the firm performance. We find that not every transaction cost is a dead weight loss in terms of product performance. Most notably we find that ex-post dispute costs are associated with higher product performance when there is a major incident such as component failure between the OEM and the supplier.
Methodologically, this dissertation proposes to use a combination of field work, mathematical modeling, conceptual theory building, and empirical analysis of primary data about firm practices.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: An Integrated Power Electronic System for Off-Grid Rural Applications

contributor:
Emadi, Ali
Schofield, Nigel
Electrical and Computer Engineering

subject:
off-grid
distributed energy
DC-DC converter
standalone
rural
buck
boost
inverter
integrated converter

abstract:
Distributed energy is an attractive alternative to typical centralized energy sources specifically for remote locations not accessible to the electricity grid. With the continued
advancement into new renewable technologies like solar, wind, fuel cell etc., off-grid standalone systems are becoming more attractive and even compeating on a
cost basis for rural locations. Along with the environmental and sustainable movement,
these technologies are only going to get more and more popular as time goes
on. Power electronic converters are also advancing which will help the shift in electricity
options. Creating innovative power electronic systems will be important when
moving toward smaller, more e cient and higher power density solutions.
As such, this thesis will aim to design and create an integrated power electronic
system for an o -grid standalone solar application designed for remote rural locations
with no access to electricity, or in locations which could bene t from such a system.
It is designed for a DC input source from 24V-40V, such as a solar panel, and can
operate four di erent loads; one 12V-24V 100 W DC load, charge a 48V battery, run
three 5V cell phone charger outputs and run one 230V, 50Hz, 1 kW AC load. A
boost converter, buck converter, phase shifted full bridge isolated DC-DC converter
and a single phase inverter are implimented in the integrated system to achieve these outputs. A comparison of similar products on the market are presented and compared
with the proposed design by showing the product speci cations, advantages
and disadvantages of each.
A discussion of each converter in the system is presented and will include operation,
design and component selection. An in-depth design process for the inductor
within the boost converter is presented and will cover core, winding design and an
optimization algorithm using the Genetic Algorithm (GA) is used to compare di erent
ferrite based C-C shaped inductors. More speci cally, the core material selected
is Ferroxcube 3C97 and the inductor comparions are between di erent Litz bundled
windings from New England Wire Tecnologies and a customized rectangular winding.
The GA optimizes around the lowest volume by comparing the di erent inductor
designs using the di erent Litz winding constructions and the custom rectangular
winding constrictuion. The rectangular winding achieves the lowest volume and will
be compared with a three phase interleaved boost design implimenting a CoilCraft
inductor. The buck converter is the simplest converter and is designed using the traditional
methods in literature. An in-depth design process for the phase shifted full
bridge converter is also done wherein the zero voltage switching (ZVS) is achieved.
The DC-AC inverter is the last converter designed within the integrated system and
covers input capacitor sizing, and output  lter design. There are speci c distributed
energy standards that must be followed when connecting loads to the system and so
the purpose of the  lter is to  lter out the voltage harmonics. The control techniques
for each converter is also discussed and shown to operate in both simulation and in
experimentally.
The losses within the system are discussed and the required equations are de ned

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Rough Sets, Similarity, and Optimal Approximations

contributor:
Janicki, Ryszard
Computing and Software

subject:
Approximation
Rough Sets
Similarity
Optimal Approximation

abstract: Rough sets have been studied for over 30 years, and the basic concepts of lower and upper approximations have been analysed in detail, yet nowhere has the idea of an `optimal' rough approximation been proposed or investigated. In this thesis, several concepts are used in proposing a generalized definition:  measures, rough sets, similarity, and approximation are each surveyed. Measure Theory allows us to generalize the definition of the `size' for a set. Rough set theory is the foundation that we use to define the term `optimal' and what constitutes an `optimal rough set'.  Similarity indexes are used to compare two sets, and determine how alike or different they are. These sets can be rough or exact. We use similarity indexes to compare sets to intermediate approximations, and isolate the optimal rough sets. The historical roots of these concepts are explored, and the foundations are formally defined. A definition of an optimal rough set is proposed, as well as a simple algorithm to find it. Properties of optimal approximations such as minimum, maximum, and symmetry, are explored, and examples are provided to demonstrate algebraic properties and illustrate the mechanics of the algorithm.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: Until now, in the context of rough sets, only an upper and lower approximation had been proposed. Here, an concept of an optimal/best approximation is proposed, and a method to obtain it is presented.


title: Flow-Induced Noise of Perforated Plates at Oblique Angles of Incidence

contributor:
Ziada, Samir
Mechanical Engineering

subject:
Aeroacoustics
Fluid-Dynamic Feedback
Architectural Acoustics
Flow-Induced Noise
Wind Engineering
Fluid Mechanics
Fluid-Structure Interaction
Acoustic Tone Generation

abstract: In this thesis, the tonal noise produced by flow over perforated plates at oblique angles of incidence is studied experimentally. A two-dimensional model of a perforated plate is used, where the circular holes of a typical perforated plate are replaced by a series of long rectangular Aluminum slats with an adjustable gap width between them. The slats are 3.175 mm thick and the gap width between them is set to 3.175 mm, 6.35 mm, and 12.7 mm. This simplified model is mounted at the exit of an open-loop wind tunnel and tested at angles of incidence of 0° to 40° and flow velocities of 0 to 30 m/s. An angle of 0° is defined as flow parallel to the plate. The acoustic response is studied using microphone measurements, and flow visualization is done using particle image velocimetry. The effect of the angle of incidence, flow velocity, gap width, and streamwise position are investigated. The flow visualization reveals that tonal noise is produced by the periodic shedding and impingement of vortices at the trailing edge of the gaps. Vortices form in the unstable free shear layer originating at the leading edge of the gap and impinge on the downstream side of the gap. At the downstream corner, these vortices separate into vortex pairs, consisting of one positively rotating and one negatively rotating vortex. These vortices are shed periodically, leading to the production of tonal noise at the shedding frequency. The effect of the angle of incidence is investigated by changing the angle of the plate with respect to the flow. For a given gap width, tones are produced only for a specific range of angles. Depending on the plate geometry, this range of angles is typically around 5° to 30°. Within this range of angles, the free shear layer impinges on the downstream side of the gap. For angles which are too small or too large, the free shear layer misses this downstream side and tones are not produced. For a larger gap width, tones are produced at smaller angles of incidence. Similarly, for a given plate geometry, there is a preferred range of flow velocities at which tonal noise is produced. The velocity at which the free shear layer is the most unstable at the tone frequency produces the strongest vortices and the loudest tones. The optimal velocity is lower for larger gap widths. Finally, it is found that the magnitude of the produced tones increases in the streamwise direction over repeated gaps along the length of the plate. This is due to the local flow conditions changing in the streamwise direction, only reaching the optimal conditions after a certain length of the plate.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: QUITTING SITTING: COMMUNICATING STRATEGIES FOR REDUCING SEDENTARY BEHAVIOUR TO HEALTHY, WORKING ADULTS

contributor:
Richardson, Julie
Rehabilitation Science

subject:
sedentary behaviour
intervention
systematic review
adults

abstract:
The purpose of this thesis was to determine the effectiveness of strategies to reduce sedentary
behaviour (SB) and to communicate these strategies to healthy adults working in academic
occupations using an educational video. Study One was a systematic review and meta-analysis of published literature on strategies to reduce SB in the home and workplace environments for
healthy adults. Study Two was a single group pre-post study design to determine the effect of an educational video on viewers’ health beliefs related to reducing SB and daily sitting time. The
information gained from these studies could be used to inform future interventions to reduce SB
in the adult population.

abstract: Thesis

abstract: Master of Science Rehabilitation Science (MSc)


title: Development of Human Visual Cortex: A Neurobiological Approach

contributor:
Murphy, Kathryn M
Neuroscience

subject:
human visual cortex
development

abstract:
Human visual perception changes across the lifespan that relies on changes in synaptic plasticity in the visual cortex.  Anatomical studies of the visual cortex, however, suggest human V1 develops early and remains relatively constant from childhood and on. Animal models have pin-pointed specific neurobiological mechanisms that are necessary for the development of visual plasticity and receptive field properties in the visual cortex. Very little is known, however, about how those synaptic mechanisms develop in the human visual cortex to support plasticity and perception across the lifespan.
This thesis addresses this gap by providing new studies on the development of those neurobiological mechanisms in postmortem human visual cortex cases that range in age from 20 days to 79 years. The main findings from this thesis support prolonged development of plasticity mechanisms in human V1 that could be characterized in 5 stages of change across the lifespan: booting up synaptic function in infancy, high neural variability in young childhood, peaks of development in older childhood, prolonged plasticity in adulthood, and return to juvenile-like state in aging. In addition, I show a contrasting development of synaptic plasticity mechanisms in V1 and extrastriate areas that suggest higher order visual perception is processed differently. I also highlight a modernized technique for isolating synaptoneurosomes in human brain that helps quantify synaptic proteins using postmortem human tissue. Together these findings aid in the translation of neurobiological mechanisms in animal models for identifying new therapeutic targets for recovery in human visual disorders and vision loss.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: The ability to see the world constantly changes from birth to old age, and depends on the health and function of our brain. The visual cortex is the part of the brain that processes vision, and it is made up of millions of cells that connect to each other through billions of synapses. Fine-tuning those connections and networks in the brain leads to better vision. The ability for connections to be fine-tuned by experience is called plasticity, and it is necessary for developing good vision. This thesis addresses the development of plasticity in the human brain by measuring levels of proteins that are responsible for controlling plasticity and vision. My findings suggest that humans have a longer period of plasticity for developing good vision than previously thought. These findings will help identify new targets to rescue vision loss that occurs in aging or visual disorders across the lifespan.


title: A New Analytical Model for Tool Life in Metal Stamping

contributor:
Jain, Mukesh K.
Mechanical Engineering

subject: analytical model, tool life, metal stamping, stainless steel, hole diameter, variation, elongation

abstract:
 Tool life during the precision stamping of stainless steel sheet (AISI 301) has been studied with particular emphasis on reduction in the punch diameter and part hole size due to tool wear. Two analytical models for predicting tool life in terms of number of quality parts that could be stamped between two re-grindings have been proposed using a combination of Archard's wear model and punching force. The proposed tool life models have been verified by experiment trials with a round M2 punch and die. The trials were carried out on a precision
progressive die in an industrial environment.

 The first tool life model calculates the pierced hole diameter variation for a given tool from sheet material properties and gives an estimation of number of parts that could be stamped for a given tolerance on a hole size. The second tool life model calculates number of parts with respect to the allowed burr height. Both
of the proposed models are derived using sheet material properties such as sheet thickness, strength coefficient (K), strain hardening index (n) and material elongation (A); process parameters such as die clearance and friction coefficient; punch characteristics such as normalized wear rate, punch diameter and punch edge radius. Finite element analysis was also employed to simulate the hole piercing process to predict burr height. The results from the proposed tool life models, FE modeling and the experiments are in good agreement.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: A Dust Flow Separator Type Electrostatic Precipitator for Diesel Engine Particulate Matter Control

contributor:
Ching, C. Y.
Ewing, D.

subject: dust flow, separator type, electrostatic precipitator, diesel engine, particulate matter control

abstract:
 Increasingly stringent legislation governing the emissions of diesel engine particulate matter (DPM) has required the development of technological improvements to diesel engines, fuels and exhaust treatments. A main focus of diesel particulate matter abatement is on exhaust after treatment, that consists of the removal of particulate matter from the exhaust gas after it exits the engine. This is currently accomplished with regenerative diesel particulate traps that are effective at removing DPM, but are costly and introduce a significant pressure drop in the exhaust flow.

 The objective of this study was to evaluate the potential of a novel particulate removal system consisting of a particulate flow separator combined with electrostatic precipitators (ESPs). Previous application of this system to natural gas emissions resulted in collection efficiencies larger than 90% with negligible pressure drop.

 The ESPs used in the proposed flow separator-ESP were characterized and have collection efficiencies of up to 99% at the flow rates studied. The flow separator-ESP was characterized with a straight inlet section and an expanding inlet section. The collection efficiency of the flow separator-ESP configured with the expanding inlet section was up to 60% for a flow rate of 2.5 kg/hr, that corresponded to laminar flow with Reynolds number of 1100. Collection efficiencies on the order of 20% were obtained for exhaust flow rates of 3.75 kg/hr (Re = 1500) and 5.0 kg/hr (Re = 2100) for both inlet configurations, and 2.5 kg/hr with the straight inlet. The effectiveness of the current design is limited by exhaust flow rate.

 The diesel exhaust gas was sampled using a partial flow dilution tunnel developed specifically for this study. The dilution ratio for this system can be estimated to within ±10% using volumetric flow measurements. It was found that changes in the dilution and sampling velocity ratios for diesel exhaust have some effect on measured particulate matter mass concentrations.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: PSEUDOLOGY: LYING IN ART AND CULTURE

contributor:
O'Connor, Mary
English and Cultural Studies

subject: pseudology, lying, contemporary art, postmodernism, performance, installation, Marcel Duchamp, Robert Rauschenberg, VALIE EXPORT, Carol Duncan, Mierle Laderman Ukeles, Guillermo Gómez-Peña, Coco Fusco, Joshua Schwebel, Iris Häussler, Donald Trump

abstract: This dissertation draws upon Western literature in critical theory, aesthetics, art theory, and art history to explore how lying can foster aesthetic experience and the sociopolitical effects of this experience. It nominates the idea of pseudology—lying as an art—and outlines its distinguishing features from the dawn of postmodernism to contemporary practices. This study demonstrates an analysis of lying premised on an understanding of aesthetics as caught up in the wider issues of public pedagogy and everyday politics. Taking as case studies specific works of Marcel Duchamp, Robert Rauschenberg, VALIE EXPORT, and Carol Duncan, this dissertation argues for the narrative framing of artwork as paramount for its reception. As well, by examining the artistic mystifications of Mierle Laderman Ukeles, Guillermo Gómez-Peña, Coco Fusco, Joshua Schwebel, and Iris Häussler, this dissertation analyzes the use of pseudology in institutional critique. The study finds that perfidious practices can point to the importance of the relational boundary between what is real/unreal, highlight the social construction of this boundary’s aesthetic aspects, and reveal the ways in which each of us are active in the construction of a shared reality. Ultimately, our active framing of everyday life and the affective nature of our construction of a shared reality has been problematized by a contemporary prevalence of lying in the realms of public culture and politics. Pseudology reveals the power of narrative framing. The pseudological artworks discussed here expose, as models for the political aesthetic of lying, the need to debate the very tenets of reality constantly and continually—an essential civic action in the ethical, communal relationships of a democracy.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: An analysis of the use of lying as an artistic technique.


title: POINTS OF REFERENCE: PROJECTILE POINTS, HUNTING AND IDENTITY AT THE NEOLITHIC ÇATALHÖYÜK, TURKEY

subject: hunting, projectile points, Neolithic Anatolia, bifaces, Çatalhöyük, Near East, obsidian

abstract:
This thesis examines the practice of hunting within the Neolithic community of Çatalhöyük by focusing on its stone projectile points. Wild faunal remains indicate that hunting remained in practice, even though domesticated animals and plants comprised the staple diet of the Neolithic people of Çatalhöyük. Hunting and the “wild” are venerated in the site's iconography (wall paintings, wild bull skull mural installations, zoomorphic figurines), while obsidian projectile points—the dominant hunting weapons— were carefully executed artifacts that seem to have served more than one purpose. In studying the projectile points I consider the role of hunting at Çatalhöyük and its significance in shaping personal and communal identities.

By employing an attribute analysis I examined the projectiles’ deposition in varied contexts (caches, burials, building infills, middens etc). Differences in use-wear traces as well as in technological and morphological traits suggest that the Çatalhöyük point assemblage consists of two groups that were used and treated in very distinct ways. The first group comprises projectile weapons that were used in hunting, exhibiting clear signs of actual use; whereas the second group consists of bifaces that were in all likelihood reserved for ceremonial purposes given their pristine condition and special deposition.

This thesis argues that hunting was not merely an alternate subsistence strategy but an arena where symbolic expression and social identities could be performed and negotiated.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: This thesis researches the role of hunting in one of the earliest agricultural societies with livestock, Çatalhöyük in Turkey (7th-6th millennium cal BCE). For this purpose I studied the stone tips of projectile weapons, i.e. arrows and spears. The results of this work show that apart from the actual hunting weapons, the people of Çatalhöyük also had weapons reserved for ceremonial purposes. Indeed other evidence also shows that hunting and the “wild” was revered at the site: wall paintings, wall decorations with wild animal skulls, large feasting events, and animal figurines. In this thesis I argue that hunting was not only a strategy for the farmers of Çatalhöyük to acquire extra food resources but it also played a significant role in their symbolic and religious life, which is why this tradition persisted even after the domestication of animals.


title: Blind Deconvolution Based on Constrained Marginalized Particle Filters

contributor:
Reilly, J.
Electrical and Computer Engineering

subject: blind deconvolution, constrained, marginalized, particle filters, robustness

abstract: This thesis presents a new approach to blind deconvolution algorithms. The proposed method is a combination of a classical blind deconvolution subspace method and a marginalized particle filter. It is shown that the new method provides better performance than just a marginalized particle filter, and better robustness than the classical subspace method. The properties of the new method make it a candidate for further exploration of its potential application in acoustic blind dereverberation.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Pharmaceuticals and Physics: Drugs and Membranes

contributor:
Rheinstadter, Maikel
Physics

abstract:
Active pharmaceutical ingredients (APIs) are usually designed to stick to some target in the body. This target is typically a protein, and the drug is supposed to change how that protein functions. However, side-effects are an inevitable consequence of introducing foreign molecules, such as drugs, into the body, since drug molecules are more than likely to interact non-specifically with other cellular structures, such as lipid membranes. The membrane is a highly relevant structure, as it is a ubiquitous biological interface, that defines the surface of cells and also internal cell components. The membrane is more than just a wall, as it plays an important role in controlling processes on the cell surface. Drug molecules have been shown to interact with membranes by non-specific Van- der-Waals interactions. However, not enough is known regarding how drugs influence the membrane structure, or how to design drugs that minimize membrane related side-effects.
X-ray and neutron scattering techniques, as well as Molecular Dynamics simulations, are capable of providing the molecular details. Synthetic membranes may be prepared with any lipid or drug composition and are tools for modelling interactions. In this thesis, I used scattering experiments on synthetic systems to study drug-membrane interactions on the atomic and molecular scales, in order to understand how the drugs influence membrane properties. I optimized the use of scattering techniques for determining drug effects on membranes.
From my research, there are two main insights.
1. Drug-membrane interactions disrupt local membrane structure. This is based on a case study of aspirin where, over three studies, I presented evidence that the aspirin disrupts cholesterol in the lipid membrane. X-ray and neutron scattering techniques, in combination with Molecular Dynamics simulations were used to determine that aspirin’s impacts are the result of locallized disruptions to the lipid structure.
2. I also present three case studies for how the properties of the membrane itself play a role in shaping the drug interaction. Biophysical properties, such as hydration and stiffness, tune how the drug interacts with the membrane. X-ray and neutron scattering are required to generate the molecular picture for why the specific biophysical membrane properties are relevant.
The set of interactions discovered here are not, by any means, exhaustive. However, the work demonstrates that molecular level details reveal unique insights on drug-membrane interactions, details that may be useful when designing drugs and mitigating their side effects.

abstract: Thesis

abstract: Doctor of Science  (PhD)


title: Intracortical Myelin in Bipolar Disorder and its Relation to Cognitive Function and Peripheral Blood Markers

contributor:
Frey, Dr. Benicio N.
Steiner, Dr. Meir
Neuroscience

abstract:
Introduction:
White matter abnormalities are routinely implicated in the pathophysiology of Bipolar Disorder (BD). Although the cerebral cortex is primarily composed of gray matter, myelinated axons are present throughout the cortical layers, most abundantly in the deeper layers. This is known as intracortical myelin (ICM). Many prior studies have shown that there are decreased counts and compromised integrity of oligodendrocytes in the prefrontal cortex of individuals with BD, in addition to altered expression of myelin protein genes. We have previously shown loss of ICM in the medial frontal gyrus in BD, using both MRI and histology.  We, along with other groups, have also shown that in healthy humans, the development of ICM follows an “inverted-U” trajectory. To our knowledge, no prior studies have investigated whole brain ICM in BD in vivo.
The first aim of this thesis was to explore whole-brain age-related ICM maturation over young adulthood in individuals with BD-I in comparison to controls, using T1-weighted MRI, and determine whether this was associated with any clinical variables such as the age of onset, duration of illness, number of mood episodes, lifetime psychosis, and medication use.
Due to ICM’s essential function of maintaining neural synchrony and the integrity of local neural connections within the cerebral cortex, its role in preserving cognitive function is becoming increasingly recognized. Although poor cognitive function persists through euthymic states in BD, its neurobiological correlates remain undetermined. The second aim of this thesis is to examine whole-brain ICM content and cognitive function in individuals with BD-I and controls.
Lastly, we explore whether the association between ICM and cognition is mediated by peripheral blood markers of the inflammatory response- C-Reactive Protein (CRP) and anti-myelin basic protein (anti-MBP).
Results:
ICM follows an “inverted –U” pattern over age in healthy controls (p<0.05). In BD, this association with age is lost throughout the cortex, and appears to plateau. These effects are seen throughout cortex, but have the greatest magnitude in motor and premotor regions, followed by prefrontal and parietal regions. Exploratory analyses show that ICM is also associated with duration of illness, age of onset, the number of manic, hypomanic and mixed episodes, and mood stabilizer and antipsychotic use, although this does not survive correction for multiple comparisons.
In BD, verbal memory (VM) performance was strongly predicted by ICM throughout a cortical network identified a priori in association with performance. Executive function, processing speed, and reaction time were also predicted by ICM, although this does not survive Bonferroni correction.
Serum analysis showed that CRP was only associated with ICM in the right anterior cingulate cortex in BD, but not controls (Chapter 4). Further, CRP was associated with performance on verbal memory and Stoop tasks.  anti-MBP levels were associated with ICM in regions of the bilateral visual, parietal, and somatosensory cortices, and left temporal, cingulate, and orbitofrontal cortices in healthy controls. In BD subjects, anti-MBP levels were only associated with ICM in the left caudal medial visual cortex and the right cuneus. Anti-MBP was not associated with cognitive performance in either BD or control subjects.
Conclusion:
The results from this thesis suggests a deficit in ICM maturation in young adults with BD. Whether this is developmental in origin is unclear. Further, ICM predicts cognitive performance on region-related tasks in BD, particularly verbal memory. Our work provides a novel potential structural correlate of cognitive performance in BD, and has significant implications for the underlying pathophysiology of cognitive dysfunction in the illness. We also identify anti-MBP as a potential marker of myelin maintenance and regenerative potential.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: An Evaluation of the PrediXcan Method for the Identification of Lipid Associated Genes

title: Evaluation of PrediXcan for Associating Lipids with Genes

contributor:
Canty, Angelo J
Statistics

subject: Gene-based association

subject: Single nucleotide polymorphism

subject: Lipids

subject: Insulin-dependent diabetes mellitus

subject: Diabetes control and complications trial

subject: Regression analysis

abstract: PrediXcan, an imputed gene expression-trait association method, was compared to multiple linear regressions (MLR) of single nucleotide polymorphisms (SNPs) using the quantitative phenotypes serum total cholesterol (TC), low-density lipoprotein cholesterol (LDL), high-density lipoprotein cholesterol (HDL) and triglycerides (TG).   The gene expression prediction models were trained using transcriptome- and genome-wide data from Depression Genes and Networks (DGN whole blood) and Genotype-Tissue Expression (GTEx) Project (GTEx whole blood, GTEx pancreas and GTEx liver).  Linear combinations of the effect sizes derived using elastic net or least absolute shrinkage and selection operator (LASSO) with genotypes from 1304 European patients from the Diabetes Control and Complications Trial (DCCT) were used to estimate the genetically regulated expression (GReX) for genes.  Different gene expression predictors were present in each training set. The 10-fold cross-validated predictive performance, estimated GReX, and p values from associations for matched genes were weakly correlated across training sets and strongly correlated for models derived using elastic net and LASSO.   MLR models had more significant associations than PrediXcan models and larger inflation factors for p values.  A comparison of p values for matched genes between PrediXcan and MLR models showed weak correlations but strong evidence for LDL and HDL associations with genes at locus 1p13.3 and 16q13, respectively.

abstract: Thesis

abstract: Master of Science (MSc)


title: Applications in Time-Frequency domain analysis

contributor:
Von Mohrenschildt, Martin
Software Engineering

subject:
Time-Frequency
Wavelet
Morlet Wavelet
EEG
Modal
Analysis
Mechanical
Event
Related
Spectral
Perturbation
Continuous
Wavelet
Transform
Short
Time
Fourier
Transform

abstract: Time-Frequency decomposition is a signal processing method for analyzing and extracting information from aperiodic signals. Analysis of these signals are ineffective when done using the Fourier transform, instead these signals must be analyzed in the time and frequency domain simultaneously. The current tools for Time-Frequency analysis are either proprietary or computationally expensive making it prohibitive for researchers to use. This thesis investigates the computational aspects of signal processing with a focus on Time-Frequency analysis using wavelets. We develop algorithms that compute and plot the Time-Frequency decomposition automatically, and implement them in C++ as a framework. As a result our framework is significantly faster than MATLAB, and can be easily incorporated into applications that require Time-Frequency analysis. The framework is applied to identify the Event Related Spectral Perturbation of EEG signals; and to vibrational analysis by identifying the mechanical modal parameters of oscillating machines.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: The Divine Name in Early Judaism: Use and Non-Use in Aramaic, Hebrew, and Greek

contributor:
Machiela, Daniel
Religious Studies

subject: Early Judaism, Tetragrammaton, Divine Name, Titles, Epithets

abstract: During the Second Temple period (516 BCE–70 CE) a series of developments contributed to a growing reticence to use the divine name, YHWH. The name was eventually restricted among priestly and pious circles, and then disappeared. The variables are poorly understood and the evidence is scattered. Scholars have supposed that the second century BCE was a major turning point from the use to non-use of the divine name, and depict this phenomenon as a linear development. Many have arrived at this position, however, through only partial consideration of currently available evidence. The current study offers for the first time a complete collection of extant evidence from the Second Temple period in Aramaic, Hebrew, and Greek in order answer the question of how, when, and in what sources the divine name is used and avoided. The outcome is a modified chronology for the Tetragrammaton’s history. Rather than a linear development from use to avoidance, the extant evidence points to overlapping use and non-use throughout most of the Second Temple period.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: The Effect of an Externally Applied Magnetic Field on the Hydrogen Absorption Properties of LaNi5

contributor:
Xu, Gu
Materials Science and Engineering

subject:
magnetic field
hydrogen absorption

abstract:
Hydrogen fuel cell applications are set to ameliorate the world's energy woes, yet there still exists problems that need to be overcome in terms oftheir fuelling. While compressed storage, cryogenic storage, chemical storage, and adsorptive storage solutions exist, none meet the requirements that are needed to facilitate a replacement for the gasoline powered automobile.
Metal hydrides have been long studied as an alternative method for storing hydrogen safely and efficiently, with significant developments being made in advanced alloys. While this research is beneficial, it was theorized that an externally applied magnetic field might augment the storage properties of existing magnetically susceptible metal hydrides, without trial and error alloy development. Constant volume hydrogen absorption experiments were conducted using LaNi5 in order to test this theory. A known amount of LaNi5 was exposed to hydrogen, with the absorption equilibrium data collected over a period of 6 hours. An equal sample was then exposed to hydrogen with a 0.7 Tesla applied field applied to the sample. There was a distinct difference between the absorption curves of the two equal samples, with the sample under the influence of the magnetic field achieving an absorption of only 0.60% wt. in comparison with the unmodified sample which absorbed 0.88% wt. It was concluded that the presence of an externally applied magnetic field has a negative effect on the overall capacity of LaNis through the prevention of a shift in the inner lattice structure of LaNis that would otherwise permit an increased hydrogen capacity. This effect while negative in terms of overall storage capacity could have a possible benefit in terms of the desorption of the stored hydrogen, as the magnetic field could be used in lieu of an increase in temperature in order to drive the hydrogen from the fully filled structure.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: The Effects of Time and Events on the Perception of Nonadjacent Key Relationships

contributor:
Woolhouse, Matthew
Psychology

subject:
music theory
music cognition
memory
nonadjacency
nonadjacent key relationship
time
number of events
tonal perception
tonal loop
working memory
modulation
probe cadence

abstract: Includes an exploration of working memory models from a musical standpoint.

abstract: A musical key can only be retained in memory for approximately 20 seconds. However, other factors may be influencing the strength of this retention. The current study tests the influence of time and number of events (chords) in an intervening key on the deterioration in memory of a nonadjacent key. Stimuli first established a major key using traditional harmonic rules, then modulated to an intervening key that was either 6 or 9 seconds in duration and formed from either 4 or 6 chords. Stimuli then returned to the original key in a probe cadence. Participants were asked to rate this cadence in terms of its sense of closure. It was revealed that there is a significant negative effect of time on the probe cadence though no effect of number of events was found. This suggests that spending more time in an intervening key, and not the number of intervening chords, diminishes the memory of the original key. However, it is unclear from this study where in memory the nonadjacent key relationship is processed. Relevant literature is examined to form a working hypothesis with the goal of strengthening future studies with a capable foundation in memory research and theories.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: We have a very short memory span for musical keys. Humans can only remember a key for approximately 20 seconds after it’s changed. However, it is unclear whether it is time spent away from the key that makes us forget or if it is the number of chords we heard in a second, interrupting key. The current study tests this distinction using nonadjacent key relationships—in which a key is established, a different key interrupts for a random amount of time and number of chords before returning to the original key for two target chords. Results confirmed previous findings as there was a significant effect of time on memory. However, there was no effect of number of chords, suggesting that it is the length of time spent away from a key, not number of chords that has an effect on memory.


title: Optimal Precorder Design for MIMO Communication Systems Equipped with Decision Feedback Receivers

contributor:
Wong, Kon M.
Electrical and Computer Engineering

subject: optimal precorder design, MIMO communication systems, decision feedback receivers, channel state information

abstract:
 We consider the design of the precoders for a multi-input multi-output (MIMO) communication system equipped with a decision feedback equalizer (DFE) receiver. For such design problems, perfect knowledge of the channel state information (CSI) at both the transmitter and the receiver is usually required. However, in the environment of wireless communications, it is often difficult to provide sufficiently timely and accurate feedback of CSI from the receiver to the transmitter for such designs to be practically viable.

 In this thesis, we consider the optimum precoder designs for a wireless communication link having M transmitter antennas and N receiver antennas (M < N), in which the channels are assumed to be flat fading and may be correlated. We assume that full knowledge of CSI is available at the receiver. At the transmitter, however, only the first- and second-order statistics of the channels are available. Our first goal is to come up with an efficient design of the optimal precoder for such a MIMO system by minimizing the average arithmetic mean-squared error (MSE) of zero-forcing (ZF) decision feedback detection subject to a constraint on the total transmission power. Applying some of the properties of the matrix parameters, this non-convex optimization problem can be transformed into a convex geometrical programming
problem which can then be efficiently solved using an interior point method. The
performance of the MIMO system equipped with this optimum precoder and a ZF-DFE
has also been found to be comparable, and in some cases, superior to that of V-BLAST which necessitates optimally ordered successive interference cancellation based on the largest post-detection signal-to-noise ratio (SNR). In terms of trade-off between performance and implementation simplicity, the proposed system is certainly an attractive alternative.

 In addition, we also utilize these important properties of our system parameters to investigate an "inverse problem" of our first design. That is, we design another precoding matrix by minimizing the total transmission power of the MIMO communication system subject to a constraint on the average MSE. Also, a closed-form solution is derived when the channels are uncorrelated while simulation results for the minimum power precoder designs is given at the end of this thesis.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: FPGA Platform for Real-Time Simulation of Tissue Deformation

contributor:
Jeremic, Aleksandar
Electrical and Computer Engineering

subject: FPGA platform, real-time simulation, tissue deformation, matrix-by-vector, accelerator

abstract:
 The simulation of soft tissue deformations has many practical uses in the medical field
such as diagnosing medical conditions, training medical professionals and surgical planning. While there are many good computational models that are used in these simulations, carrying out the simulations is time consuming especially for large systems. This is because most simulators are based on software, which are run on general-purpose computers (GPC) that are not optimized to carry out the operations needed for simulation. In order to improve the performance of these simulators, field-programmable-gate-arrays (FPGA) based accelerators for carrying out Matrix-by-Vector multiplications (MVM) have been implemented by Ramachandran in 1998 and Zhuo et. al. in 2005. Zhuo et. al. also looked at the best ways to store a matrix in memory, and how this is affected by certain properties of the matrix.

 A better approach is to implement an accelerator for carrying out all operations required
for simulation on hardware. In this study we propose a hardware accelerator for simulating soft-tissue deformation using finite-difference approximation of elastodynamics equations based on conjugate-gradient inversion of sparse matrices. We designed and implemented the accelerator, which is optimized for use with sparse matrices, on FPGA. We also conducted performance and resource requirements analysis for the accelerator. Our results show this approach is capable of achieving sufficiently high computational rate for carrying out real-time simulation; even with large grids or meshes. Finally, we developed computational models for carrying out real-time simulation of tissue deformation.

abstract: Thesis

abstract: Master of Applied Science (MASc)