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A Concise and Critical Art History of the Northwest Territories
Get PDFThis thesis offers a comprehensive exploration of the art systems in the Northwest Territories (NWT) and their evolution over time. It investigates how the history of promoting, exhibiting, and funding northern art has significantly shaped the current artistic climate for NWT artists. Through a multi-faceted approach, the research delves into the unique aesthetics of the NWT, examining the impact of materiality, critical craft theory, and the terminology used to categorize art and craft, and how these factors influence the reception of NWT art.
The thesis also analyzes the transformative event of the 1999 division of the NWT and Nunavut territories, which left an indelible mark on all aspects of northern life and played a pivotal role in shaping the visual identity of the North. A unique focus is placed on the development of Inuit art, tracing its historical trajectory and, notably, the findings from the carefully compiled resource, "Visual Arts in the Northwest Territories: A Timeline" (Appendix A), created during the course of this research.
In addition to historical and artistic analysis, the research provides an in-depth examination of the current NWT arts landscape. It investigates the intricate relationships between arts organizations, the local community, and cultural policy, highlighting their collective impact on the contemporary arts scene. Moreover, the thesis offers valuable insights into the challenges and opportunities that NWT artists confront in their creative endeavors within the territory today.
In summation, this thesis offers a nuanced and comprehensive view of the art history and current artistic environment in the Northwest Territories. It contributes to a deeper understanding of the region's distinctive artistic identity, the socio-political influences that have shaped it, and the challenges faced by NWT artists in the present day
Modeling and Control of Dielectric Elastomer Enabled Actuators for Soft Robots
Get PDFThe field of robotics has undergone a significant transformation, extending its scope well beyond its traditional role in manufacturing automation. It has now found applications in various domains such as healthcare, field exploration, and collaborative human-robot interactions. Nevertheless, a main concern across these diverse applications remains the safety of interactions involving humans. Traditional robots, comprised of rigid links and joints, inherently carry risks when operating close to human beings. This risk is exacerbated by the absence of compliance in their actuation mechanisms. In contrast, soft robots are constructed from inherently soft or extensible materials, affording them the ability to deform and absorb energy during collisions. This distinctive characteristic endows them with a continuously deformable structure and muscle-like actuation, closely resembling biological systems and offering a greater number of degrees of freedom. Consequently, soft robots hold the potential to exhibit extraordinary levels of adaptability, sensitivity, and agility.
The emergence of soft robots marks a new frontier at the intersection of multiple disciplines, including engineering, materials science, mechanics, physics, chemistry, biology, and robotics. This interdisciplinary confluence catalyzes innovation, pushing the boundaries of robotic capabilities and unlocking fresh avenues for exploration and practical applications.
Among the materials ideally suited for soft robotics, Dielectric Elastomer (DE) is one of the promising candidates due to its exceptional performance attributes. However, the intricate nonlinear characteristics inherent to Dielectric Elastomer Actuators (DEAs), including phenomena such as hysteresis, stress relaxation, and various dependencies, pose great challenges in modeling and control.
This dissertation is dedicated to advancing the modeling and control strategies for Dielectric Elastomer Actuators (DEAs) with the primary objective of integrating them into soft robot applications.
The research endeavors commence with a solid foundation in the form of extensive experimental tests. These tests investigate the input-output characteristics of DEAs, systematically exploring their responses under varying input amplitudes, frequencies, and mechanical loads. The experimental results unveil intricate and multifaceted behaviors influenced by factors such as input frequencies, amplitudes, and external mechanical loads.
This study focuses specifically on conical and planar Dielectric Elastomer Actuators (DEAs) and introduces two distinct models based on fundamental physical principles. These proposed models are inspired by the concept of free energy within viscoelastic materials, allowing them to comprehensively capture the intricate behaviors exhibited by DEAs while considering their complex dependencies. Particularly, these models can describe the intricate influences of multiple factors that shape DEA behaviors. The precision and effectiveness of these models are rigorously validated through meticulous comparisons with experimental data.
Due to the necessity for actuator-specific details in physics-based models, an innovative approach is presented, namely a data-in-loop model. This groundbreaking model adopts nonlinear elements, encompassing phenomena such as creep and hysteresis, thus avoiding the need for geometry-specific information and effectively representing the intricate behaviors of DEAs.
The presence of nonlinear effects in DEAs can lead to harmful consequences, including inaccuracies, oscillations, and instability. To effectively counter these effects, a controller design approach is proposed, adopting feedforward inverse compensation methods for controller design. In this framework, a model based on Prandtl-Ishlinskii (PI) hysteresis blocks is adopted to account for the nonlinearities within DEAs. The direct inverse compensation technique is employed with the inverse of the PI model. Building upon this foundation, a robust adaptive controller is then developed. This comprehensive methodology is designed to mitigate the adverse impacts of nonlinearities in DEAs, ultimately enhancing their control performance and addressing the formidable challenges posed by dynamic behaviors
Algorithmic Solutions for Virtual Network Function Migration in Cloud
Get PDFNetwork Function Virtualization (NFV) is a network architecture that separates network functions from dedicated hardware, implementing them as software modules known as Virtual Network Functions (VNFs), which are executed in virtual machines or containers. A Network Service (NS) consists of a chain of VNFs known as a VNF Forwarding Graph (VNF-FG). NFV increases deployment flexibility and agility within operator networks and reduces operating and capital expenditures significantly. Deploying an NS requires solving the NFV resource allocation (NFV-RA) problem, which involves the three stages of (i) VNF-FG composition, (ii) VNF-FG embedding, and (iii) VNF scheduling. Resource allocation in NFV requires efficient algorithms to determine on which physical node VNFs are embedded and to be able to migrate VNFs from one node to another. A major challenge in NFV is how to maintain reasonable VNF embedding to adapt to the changes in the network. As the VNF embedding stage may also be dynamic; it brings an additional dimension of complexity in terms of keeping track of where a given VNF is running. In other words, the VNF migration is responsible for where, when, and how to transfer the VNFs from source to destination in response to the variation in service requests. The VNF Migration problem generally refers to the process of migrating VNFs from one node to another due to specific requirements such as reduction of cost, energy saving, recovery from failures, etc. However, VNF migration faces several challenges. The first challenge arises from the mobility of end-users and the fog nodes, along with limited fog node coverage, resulting in service discontinuity and increasing application delay. A second challenge presents when there are stringent latency requirements between VNFs and can make them tightly coupled, thus hindering each VNF from being migrated individually, and resulting in poor performance. The third challenge is when we have a limitation of resources in the network. The overloaded node can significantly impact the determination of the best VNF decomposition option among all possible choices, potentially leading to a degradation in Quality of Service (QoS). VNF migration can offer great potential to address these challenges. However, the challenge remains: where, when, and which VNF should migrate to improve performance.
In this Ph.D. thesis, we aim to address the challenges in the VNF migration problem mentioned above. Firstly, we introduce a reinforcement learning-based optimization framework for application component migration in NFV cloud-fog environments where both fog nodes and end-users are mobile. More specifically, our main objective is to efficiently migrate the VNFs of a request such that the total delay and cost are minimized. Secondly, we introduce a cost-efficient solution for solving the problem of cluster migration of VNFs for VNF-FG embedding by taking into account the latency requirement between VNFs and reusing the already deployed VNFs. The objective is to migrate the cluster of VNF so that the total embedding cost, including resource, instantiation, reuse, and transmission cost, is minimized. Lastly, when considering VNF migration in the case of VNF decomposition, we investigate how VNF migration and VNF decomposition can be mutually beneficial. We achieve this by designing a joint VNF decomposition and migration approach to minimize the embedding cost of network services (NS) and promote VNF reusability. To accomplish this, we propose two efficient heuristics for identifying the best decomposition options and facilitating the migration of previously deployed VNFs across the network
Towards The Priming Effect in Sediments of the St. Lawrence Estuarine System: A Contribution using Specific Stable Carbon Isotope and Biomarker Analysis
Get PDFAquatic systems, such as the St. Lawrence Estuary and Gulf (SLEG), are represented by a combination of recalcitrant Organic Matter (OM) derived from land-based carbon-based compounds, and marine labile OM, mostly composed from phytoplankton and zooplankton biomass. The consumption of marine labile OM components by aerobic heterotrophic bacteria results in sustained pressure of dissolved O2 concentrations and accumulation of more recalcitrant OM fractions corresponding to slower degradation rates. The SLEG is a cold temperate estuarine system, characterized by large seasonal variations in riverine discharge rates resulting in sudden influxes of fresh and labile OM deposited into the sediment. The accumulation and remineralization of recalcitrant fractions (formed through in situ primary production) could be modulated by the priming effect (PE) where the change in the degradation rate of recalcitrant sediment is modulated by the addition of labile OM. The SLEG is an ideal site to study PE, where climate change has reduced dissolved O2 levels, particularly in the depths of bottom waters and affected the marine life and may have contributed to the onset and worsening of hypoxia. To examine PE, through a batch incubation experiment we attempt to measure changes in the rate of degradation in recalcitrant sediment from SLEG by adding fresh labile OM, specifically 13C-depleted phytoplankton. A time course study was developed to examine the pathway of fresh OM, particularly carbon, remains in the artificial system. Phytoplankton fixes inorganic carbon, specifically CO2 (aq), and transforms it into organic matter via photosynthesis. Since this process preferentially selects carbon-12, we expect to observe an increase of carbon-12 in the system (a lowering of the 13C/12C ratio) over time. Most of the organic matter in sediment originates from primary production in the water column, therefore the sediment’s initial delta13C value can be altered by the amount of CO2 (aq), plankton, nutrients, and light. We performed Dissolved Organic Carbon (DOC) and stable isotope analysis on the seawater samples as well as stable isotope analysis of the samples that underwent incubation. Quenching of the incubations followed by the extraction, quantification and isotopic characterization of the bacterial fatty acids and hydrocarbons allows us to examine whether there is any effect of labile OM on the mineralization of recalcitrant sedimentary OM. Finally, the experimental evaluation of the reactivity of recalcitrant OM indicated that the sedimental bulk was not reactive on the time scale of 20 and 32 days respectively, such that only additions of labile OM were quickly consumed
Essays on Strategyproof Allocation Rules on Restricted Domains
No full textThe present thesis consists of four chapters. The first chapter provides a summary of the three studies on strategyproof allocation rules on restricted domains.
In the second chapter, we consider the problem of allocating two public “bads” on two adjacent streets by two disjoint sets of agents with additive single dipped preferences. We show that any voting rule or social choice function (SCF) satisfying strategyproofness, streetwise Pareto optimality, and independence of irrelevant alternatives assigns extreme points to each profile. Moreover, such SCF or voting rule is decomposable- location of a street is determined solely by the residents of that street.
In the third chapter, I consider the problem of allocating two public “bads’’ on two adjacent streets with multi-dimensional single-dipped preferences. Each agent has a worst location on both streets. We show that any strategyproof social choice function (SCF) or voting rule satisfying Pareto optimality and independence of irrelevant alternatives selects only the extreme points of the streets as the locations of the public facilities.
In the fourth chapter, I consider the problem of allocating a perfectly divisible commodity among a group of agents with single dipped preferences. I study a subdomain of single dipped preferences and identify a sub-domain that I call the (h*, k*)-dip restricted domain. On that domain, I found that Pareto optimality and equal treatment of equals are compatible. I show that on this restricted domain, the equal sharing rule is the only rule satisfying strategyproofness, Pareto optimality and equal treatment of equals
Conciliar Ecclesiology
Get PDFEcclesiological diversity abounds in our Mother Church. So too are the ecclesiologies resplendent in the sixteen documents of Vatican II. These sixteen documents are the communitarian, cumulative, and progressive fruition of the application of ressourcement and aggiornamento, the principles of Nouvelle théologie – labelled as French Theology by Pope Francis. It is this théologie that shaped the intellectual vision which laid the theological foundation for the formulation of the documents. This article makes an academic voyage through the kaleidoscope of compelling and convincing Nouvelle théologie to unearth a Conciliar ecclesiology that acknowledges many emerging ecclesiologies reverberating with new pastoral approaches
A Novel Semi-Active Control Approach for Flexible Structures: Vibration Control through Boundary Conditioning using Magnetorheological Elastomers
Get PDFMagnetorheological elastomers (MREs) are solid analogue of the well-known smart material magnetorheological fluids (MRFs). They are composed of micron-sized ferromagnetic particles embedded in an elastomeric medium. Compared to MRFs which generally provide variable damping by variation of an applied magnetic field, MREs are capable of altering both stiffness and damping in the presence of an external magnetic field. The field-dependent viscoelastic properties of MREs can be effectively used for the development of MRE-based adaptive devices and structures to mitigate vibration semi-actively over a broad range of frequencies.
Extensive research studies have been carried out on the application of MREs in semi-active vibration isolators and absorbers. One emerging application is the use of MREs as part of structures, such as MRE-based sandwich beams and plates, with MRE acting as the core layer. MRE-based sandwich structures may be used for vibration control of light-weight flexible structures; however, their practical implementation is limited partially due to the weight of the integrated electromagnet having to be mounted onto these vibrating structures in order to activate the MRE layer.
This research explores an alternative method of vibration control of flexible beam type structures via boundary conditioning using MRE at the support location. Having the MRE at the beam support rather than the core layer resolves the mounting issue of the electromagnet on the structure itself. This study explores a novel MRE-based control method on a cantilever beam, where the cantilever beam is approximately modelled using an overhanging flexible continuous beam. The overhang support is replaced with MRE support to control the rigidity of the boundary condition. The Rayleigh-Ritz method has been effectively used to formulate dynamic equations of motions of the beam with MRE support and to extract its natural frequencies and mode shapes. The MRE based adaptive continuous beam is then converted into an equivalent single-degree-of-freedom system for the purpose of control implementation, assuming that the system’s response is dominated by its fundamental mode. Three different types of control methods are explored including optimal control based on nonlinear mathematical programming technique (NLP), proportional-integral-derivative control, and on-off control. The performance of controllers is evaluated for three different loading conditions including shock, harmonic and random vibration excitations.
The proposed method of vibration control through boundary conditioning using MRE technology can provide essential guidance on the vibration control of light-weight structures using MREs without directly integrating heavy electromagnets to energize MREs. Such a design can be retroactively fitted onto an existing structure. Applications can include electronics packaging, where the electromagnet can be placed at a safe distance from electronics that are sensitive to a magnetic field
Identification of Glycosyltransferase Inhibitor Molecules Targeting Cell-Surface Fucosylation Using High-Throughput Methods
Get PDFIn cancers, increased fucosylation of cell surface glycans is a trademark of malignant cell transformation and contributes to many aberrant cellular events during cancer development. Alterations in the expression of fucosylated oligosaccharides is mainly attributed to the upregulation of specific fucosyltransferase enzymes (FUTs), which construct fucosylated glycans using GDP-fucose as a substrate. FUT5 and FUT6 are two important enzymes of the a1-3-fucosyltransferase family that act to form sialyl LewisX, a member of the Lewis antigen family that is abnormally abundant in numerous cancers and is associated with advanced tumor grade poor prognosis due to its capacity to interact with E- and L- selectin molecules expressed by the endothelium, thus aiding in metastasis by direct binding of cancer cells.
To identify inhibitors of FUT5 and FUT6 enzymes as potential cancer therapeutics, we have developed a high-throughput coupled enzyme assay that makes use of 3’-sialyl-N-acetyllactosamine-resorufin (3’-SLN-Res), a fluorogenically labeled sialyl LewisX precursor. When non-fucosylated, this synthetic substrate is recognized and hydrolyzed by specific glycoside hydrolase enzymes (glycosidases) to release fluorescent resorufin, yet if the probe is fucosylated by FUT5 or FUT6 prior to treatment with glycosidases, these cannot act on the substrate and no fluorescent signal is produced. Employing this assay, we were able to screen a library of bioactive small-molecule compounds in a fully automated high-throughput screening and identify several hits, demonstrating that our approach can be used to single out potent FUT inhibitors from commercial compound libraries in a microtiter plate format
Thermal Modeling of an Electric Vehicle Soft Magnetic Composite Permanent Magnet Synchronous Motor
Get PDFToday, with the increasing impacts of the climate change, sustainable solutions are being searched for in many areas. Demand is increasing in the fields of energy, health, housing and transportation to meet the needs of developing economies and growing populations. In these areas, studies are being carried out to reduce the use of fossil fuels and for renewable solutions. Various solutions are being worked on for the transportation sector, which is the second biggest factor in terms of carbon emissions. One of the most important steps is electric vehicles. Electric vehicle density is increasing day by day both to reduce dependence on fossil fuels and for an environmental solution.
One of the most important steps of this evolution in transportation is the types of motors used in vehicles. The replacement of internal combustion engines by electric motors has brought about various research topics. Today, Permanent Magnet Synchronous Motors have become one of the most preferred models with the many advantages they provide for electric vehicles. With its high power density, high efficiency, ability to reach high speeds and compact size, it has become a suitable motor for electric vehicles. In addition to all these benefits, there are also some challenges that need to be solved. Thermal design is crucial to avoid the negative effects of temperature rise for high power generating motors in small sizes. In order to perform all these analyses, it is necessary to design thermal modeling to determine the temperature limits and design the cooling system.
In this thesis, the thermal equivalent models of two different PMSMs were analyzed and proposed by using the Lumped Parameter Network Method to predict temperature rise during operation. In addition, the motors were tested with real time experiments and supported by simulation results. The thermal models analyzed for the two different motors were analyzed to compare the temperature differences and to analyze the geometry in terms of temperature distribution and suitability
Exploring Automatic Speech Recognition as a Writing Tool
Get PDFThe aim of this dissertation is to explore the use of automatic speech recognition (ASR) for writing purposes and to assess its pedagogical effectiveness as a writing tool. Considering that ASR is useful for enhancing second language (L2) oral skills and pronunciation (Liakin et al., 2015), it is worth examining ASR’s pedagogical features and
limitations; whether ASR can be accepted as a writing tool; and how ASR-assisted writing can contribute to the development of writing skills. This dissertation begins with an overview of the ASR technology and its architecture, as well as the technology’s advancements throughout time, followed by an analysis of the components of writing skill, transcription
modes, and related challenges. The remainder comprises three interconnected manuscript-based chapters (Chapters 2 to 4, respectively), each of which addresses a distinct aspect of three overarching research questions: (a) What are the pedagogical benefits and limitations of ASR use for L2 pedagogy and for writing purposes? (Manuscript A); (b) What are learners’ perceptions of ASR use as a writing tool? (Manuscript B); and (c) What behaviors do learners employ when engaged in ASR-assisted writing? (Manuscript C).
The first manuscript systematically reviews the pedagogical potential and limitations of using the ASR technology in L2 learning and, more particularly, in L2 English writing. The second manuscript explores writers’ perceptions of employing ASR for writing to reveal whether writers accept ASR as a tool for composing texts. This manuscript also compares
native and nonnative English writers’ perceptions in terms of using ASR for writing. Finally, the third manuscript examines the behaviors that writers employ when composing texts with ASR and whether there is a relationship between the choice of behavior utilized and the lexical diversity of an ASR-written text.
This dissertation will further our understanding of users’ perceptions and acceptance of ASR as a writing tool by identifying both the potentials and limitations of the technology. Given that very little research has been conducted to investigate the use of ASR systems for L2 writing by adult writers (as far as the researcher is aware, there is only one study in this
field, and the handful of studies available focuses on writing by native speakers or on writers with learning disabilities), this dissertation will open a new line of inquiry in the field of L2 writing development