identifier: Leclerc, Laura  (2018) Implementation of a Novel Fucosyltransferase Inhibition Assay on a Digital Microfluidics Device.  Masters thesis, Concordia University.

abstract:
Cell-surface carbohydrates—or glycans—influence growth, differentiation, and immune response mechanisms. Alterations to the glycome can be markers for diseases including diabetes, neurodegenerative disorders, and cancer. Fucosyltransferases catalyze the addition of a fucose sugar residue to specific cell-surface glycans, which are involved in intercellular cell rolling/adhesion interactions such as white blood cells homing to inflammation sites and sperm-egg binding in fertilization. Fucosylated glycans are also implicated in inflammatory disease and cancers. In viral and microbial infections, fucosyltransferases can play a role in the adhesion and colonization of the host organism, as in the case of Helicobacter pylori α(1,3)-fucosyltransferase (FucT).
To better our understanding of glycome alterations and improve medical diagnostics and treatments, screens for glycosyltransferase activity and inhibition are needed. Efficient screens for specific glycosylations tend toward costly materials, instrumentation, and specialized skillsets- here, we present a novel inhibition assay for FucT using the fluorogenically labeled disaccharide, MU-β-LacNAc. The assay shows good potential for high throughput (Z’=0.78 in 384-well plate), though such an application is not shown here. It was also implemented on a digital microfluidic (DMF) platform, where inhibition curves of FucT by GDP, a product of the glycosyltransferase reaction that exhibits an inhibitory feed-back loop, were generated on-device. Results of the assay on DMF (IC50 = 0.093 mM ± 0.037) were shown to be comparable to results in a 384-well plate (IC50 = 0.114 mM ± 0.086), achieving a 87.5% reduction in reaction volume and setting the groundwork for future fully automated screens for potential inhibitors of glycosyltransferases.


identifier: Krasnikova, Alena  (2018) Yulia Biriukova and The Lumberman in the National Vision of Canada in the 1930s.  Masters thesis, Concordia University.

type: Thesis NonPeerReviewed

abstract: This thesis is dedicated to the artistic legacy of a little-known Russian-born Canadian painter and drawer, Yulia Biriukova (1895-1972), active in Toronto primarily during the 1930s. Using her painting The Riverman, Frenchy Renaud (1935) from the Art Gallery of Hamilton, I seek to reassess the problematic of Canadian portraiture of the interwar period through such notions as national symbols and typology. Being an individual who came to Canada as an experienced artist, Biriukova reflected the Canadian world that she saw. As a descendant of a highly educated and aristocratic family, she quickly integrated into the beau-monde of the Torontonian public and delved into the details of nationalist concerns that gained momentum in Canada after World War I. The figure of the lumberjack that she chose to paint embodies a carefully orchestrated philosophy of national unity and prosperity that this thesis offers the reader to discover.


identifier: Masoumi, Nima  (2018) Novel techniques for registration of multimodal medical images.  Masters thesis, Concordia University.

abstract: Medical image registration is a critical image processing task in many applications such as image-guided surgery (IGS) and image-guided radiotherapy. Herein, a novel automatic inter-modal affine registration technique is proposed based on the correlation ratio (CR) similarity metric firstly. The technique is demonstrated through registering intra-operative ultrasound (US) scans with magnetic resonance (MR) images of 22 patients from a publicly available database. By using landmark-based mean target registration errors (mTRE) for evaluation, the technique has achieved a result of 2.79$\pm$1.13 mm from an initial value of 5.40$\pm$4.31 mm. A nonparametric statistical analysis performed using the Wilcoxon rank sum test shows that there is a significant difference between pre- and post-registration mTREs with a $p$-value of $0.0058$. To achieve this result, the MRI was deemed as the fix image ($I_f$) and the US as the moving image ($I_m$) and then $I_m$ was transformed to align with $I_f$. Covariance matrix adaptation evolutionary strategy (CMA-ES) was utilized to find the optimal affine transformation in registration of $I_m$ to $I_f$. In addition to quantitative validation using mTRE, the results were validated qualitatively by overlaying pre- and post-registration US and MRI to allow visual assessment of the alignment. The proposed fully automatic registration method significantly improved the alignment of MRI and US images and can therefore be used to aid neurosurgeons in resection of brain tumors. In addition to proposing new methods for registration of US and MRI, three different datasets of corresponding CT and US images of vertebrae were collected and presented. In the first dataset, two human patients’ lumbar vertebrae are presented and the US images are simulated from the CT images. The second dataset includes corresponding CT and US images of a phantom, made of post-mortem canine cervical and thoracic vertebrae. The third dataset includes the CT and US images of a lamb’s lumbar vertebrae. For the two latter datasets, 15 corresponding landmarks were provided and fiducial registration of the corresponding images was performed to acquire a silver standard ground truth of the registration. This dataset will be released online to allow validation of US-CT registration techniques.


identifier: Donelle, Louis  (2018) The effects of the spatial structure of the environment on species coexistence and related consequences to local and regional community structure.  Masters thesis, Concordia University.

abstract: Spatial environmental heterogeneity is widely accepted and cited as a mechanism underlying the structure of ecological communities. Most empirical evidence related to the effects of environmental heterogeneity comes from assessing how local environments vary in relation to one another and how this variation affects community (and metacommunity) structure. However, similar levels of environmental variation are often structured differently in space, likely affecting species distributions and the ways in which they coexist. Yet, the spatial structure of environmental variation received very little attention. In this study, we set out for the first time a model to understand the effects of the spatial structure of the environment on metacommunity dynamics and its effects on species co-existence at local and regional levels. We built a metacommunity model in a spatially explicit landscape with spatially structured environmental conditions and a continuum of specialist to generalist species that competed for space. Dispersal mortality was set as a function of species’ environmental tolerances and the environmental variation experienced during dispersal. The spatial structure of the environment was found to increase local and regional coexistence, while also selecting for more specialist species. In landscapes with strong spatial structure, patches with similar environmental values were clustered together, thus facilitating the successful colonization of suitable patches by specialist species. Conversely, weakly structured landscapes selected for generalist species. As such, increased environmental spatialization fostered niche partitioning, facilitating coexistence and, as a result, increasing local and regional diversity.


identifier: Madani, Marjan  (2018) Optical Receiver with an Inductorless Continuous-Time Feed-Forward Equalizer.  Masters thesis, Concordia University.

abstract:
The exponential growth in Internet traffic is partially an outcome of increasing
social networking, cloud computing and the arrival of a variety of applications, for example,
video streaming. Accordingly, it necessitates the deployment of robust data centers
providing data transport at sufficiently high speed. By 2020, 77% of global data networking
stays within data centers and the data traffic between data centers is about 9%
reported by the Cisco Global Index 2014-2019. Short reach optical interconnects in the
data centers satisfy the demand for transfer of such an increasing volume of data. In the
year 2017, the ratio of optical to copper cabling in the data center has reached 60%.
The firrst stage in an optical receiver is a transimpedance amplifier (TIA) which
converts a small photocurrent into a voltage signal. Considering the thermal noise of
the optical receiver as the dominant source of noise, improving the sensitivity of the
optical receiver will lessen the transmitted optical power to establish a given bit error
rate (BER). In a conventional TIA, the realizable gain declines as the data rate is pushed
higher, requiring additional stages of main amplifiers and leading to a power-hungry receiver.
Recently, high-gain but limited bandwidth front ends are proposed to achieve a
high data rate with better noise performance and reduced power dissipation compared to
conventional approaches. However, the reduced bandwidth introduces significant intersymbol
interference (ISI). Discrete time feedforward equalization (DT-FFE) can cancel
ISI. Nevertheless, charge injection and clock feedthrough in the sampling circuit can degrade
the signal. Certain problems associated with discrete time approach is eliminated
in proposed design employing a continuous time FFE (CT-FFE).
The signal-to-noise ratio (SNR) at the output of TIA determines the sensitivity
of the front-end optical receiver. Modeling both the TIA and its thermal noise, by
the second-order response, the eye height and the root mean square (RMS) of the TIA
thermal noise are investigated against the typical characteristics of the model. The root
mean square (RMS) is formulated independently from the data rate. Consequently, the
conditions for which SNR reaches the highest value are extracted. Afterward, a case
study has been done for the shunt-feedback TIA using the above expressions to extract
TIA design parameters with and without an equalizer. The gaol is to reduce the power
consumption by increasing the sensitivity of the TIA. To this end, the above analyses
assist us to replace a conventional TIA following by the power-hungry stages of amplifiers
by a low-bandwidth TIA following with an equalizer.
The proposed CT-FFE is designed in CMOS 65 nm technology. The power dissipation
for the receive and decision circuit is about 13.15 mW from a 1-V supply. The
front-end has an equivalent gain of 66dB. It has an input referred noise of 0.32 uArms,
leading to an estimated noise-limited sensitivity of 4.48 uAp-p in the presence of a
pad/photodiode capacitance of 100 fF.


identifier: Luciano, Lorenzo  (2018) Geometric Deep Learned Descriptors for 3D Shape Recognition.  PhD thesis, Concordia University.

abstract:
The availability of large 3D shape benchmarks has sparked a flurry of research activity in the development of efficient techniques for 3D shape recognition, which is a fundamental problem in a variety of domains such as pattern recognition, computer vision, and geometry processing. A key element in virtually any shape recognition method is to represent a 3D shape by a concise and compact shape descriptor aimed at facilitating the recognition tasks.

The recent trend in shape recognition is geared toward using deep neural networks to learn features at various levels of abstraction, and has been driven, in large part, by a combination of affordable computing hardware, open source software, and the availability of large-scale datasets. In this thesis, we propose deep learning approaches to 3D shape classification and retrieval. Our approaches inherit many useful properties from the geodesic distance, most notably the capture of the intrinsic geometric structure of 3D shapes and the invariance to isometric deformations. More specifically, we present an integrated framework for 3D shape classification that extracts discriminative geometric shape descriptors with geodesic moments. Further, we introduce a geometric framework for unsupervised 3D shape retrieval using geodesic moments and stacked sparse autoencoders. The key idea is to learn deep shape representations in an unsupervised manner. Such discriminative shape descriptors can then be used to compute pairwise dissimilarities between shapes in a dataset, and to find the retrieved set of the most relevant shapes to a given shape query. Experimental evaluation on three standard 3D shape benchmarks demonstrate the competitive performance of our approach in comparison with existing techniques.

We also introduce a deep similarity network fusion framework for 3D shape classification using a graph convolutional neural network, which is an efficient and scalable deep learning model for graph-structured data. The proposed approach coalesces the geometrical discriminative power of geodesic moments and similarity network fusion in an effort to design a simple, yet discriminative shape descriptor. This geometric shape descriptor is then fed into the graph convolutional neural network to learn a deep feature representation of a 3D shape. We validate our method on ModelNet shape benchmarks, demonstrating that the proposed framework yields significant performance gains compared to state-of-the-art approaches.


identifier: Driscoll, Jeffrey  (2018) The influence of operational sex ratio on the mating behaviour of reindeer (Rangifer tarandus L.) during an experimental rut: the effect of male age.  Masters thesis, Concordia University.

abstract: The operational sex ratio (OSR), the ratio of sexually active males to sexually receptive females, is one of the main measures used to predict the intensity and direction of mating competition, influencing the opportunity for sexual selection. Here we conducted the first experimental study to investigate how OSR and male age impacts the intensity of mating competition and the male activity budget in a large mammalian species, reindeer (Rangifer tarandus), under semi-natural conditions. We manipulated OSR on two levels in two enclosures, a female biased treatment (3♂:6♀ = OSR 0.5) and a sex balanced treatment (3♂:3♀ = OSR 1), over two years with males from two age groups (1.5 or 2.5-years-old), and with females of various ages. We found some support for prevailing OSR theory, notably with female intrasexual competition occurring at lower frequencies in OSR = 1. An emerging trend was noted for male intrasexual competition, with higher frequencies of occurrence in OSR = 1 for our 2.5-year-old males. Courtship behaviour was also found to occur at higher frequencies of occurrence among the 2.5-year-old males, however, there was no effect of OSR. Regarding the male activity budget, we found that 1.5-year-old males followed a more income breeding strategy, with no difference in foraging behaviour between OSR treatments. In contrast, our 2.5-year-old males had a significantly lower frequency of foraging behaviour in OSR = 1, presumably resulting from a higher occurrence of intrasexual competition. Vigilance behaviour was also found to occur at higher frequencies in OSR=1 for the 2.5-year-old males, likely due to females being more limiting. Our results suggest that age is an important factor with respect to how male reindeer respond to differing OSR values. Future research aiming to expand the generalizability of experimental OSR theory to a wider range of taxa and ecological conditions need to consider other factors that will impact competition for mates, such as prime reproductive age.


identifier: Nixon, Lindsay  (2018) Prairie Families: Cree-Métis-Saulteux Materialities as Indigenous Feminist Materialist Record of Kinship-Based Selfhood.  Masters thesis, Concordia University.

abstract:
This thesis was inspired by Tootinaowaziibeeng First Nation’s administrative and patrilineal Anishinabe designation, and its erasure of the mixed Cree, Métis, and Saulteux communities that resulted in its formation. Tootinaowaziibeeng’s designation as an Anishinabe community is resultant of nationalistic historicizing that has created rigid boundaries between Cree, Métis, and Saulteux communities in the present, and an omitting of kinship webs that formed between the aforementioned communities in the nineteenth century. Kinship webs were the most important social and economic unit of plains Cree, Métis, and Salteaux communities throughout the 1800s, when a variety of Indigenous peoples were coming together in southern Manitoba to form singular camps, unified by shared teachings, common economies like the buffalo, and for mutual survivance. Cree-Métis-Saulteaux materialities—such as quillwork and beading on garments—that were made and collected in the Canadian prairies during the 1800s are material records of kinship webs that understood Cree-Métis-Saulteaux kinship as “fluid, flexible, and inclusive,” as Robert Alexander Innes has described. The use of the term materialities herein draws from Kim Tallbear’s research in the field of feminist, new materialisms, which considers the animacy of so-called objects that relate to Indigenous communities.

Applying methodologies for decolonial museology, kinship becomes a decolonial tool that animates nineteenth century Cree-Métis-Saulteaux materialities housed in the Thaw Collection at the Fenimore Museum, once enlivened in proto-feminist spaces wherein Cree-Métis-Saulteaux relationalities took form as materialities, asserting a new mixed aesthetics that represented how Cree-Métis-Saulteaux peoples saw themselves. Drawing from the family histories of the author—stories passed on from their feminine relations, kohkoms, aunties, and cousins—and research with materialities in museum archives, this thesis applies Kim Anderson’s concepts around feminist selfhood to better understand Cree-Métis-Saulteaux peoples outside of nationalistic and bureaucratic categorization. Feminine knowledges of matrilineal decent assist in making contemporary assertions of identity grounded in principles of rematriation—Indigenous selfhoods understood through kinship webs and social organization passed on through the knowledge of women’s communities.


identifier: Reguis Yadao, Dana-Rae ORCID: https://orcid.org/0000-0003-2614-4697 <https://orcid.org/0000-0003-2614-4697>  (2018) Smooth Muscle Cell Mitochondrial Respiration – Effects of Aerobic Training and Type I Diabetes.  Masters thesis, Concordia University.

abstract: Cardiovascular disease is the leading cause of death among diabetic patients, due mostly to mitochondrial dysfunction and resulting oxidative stress. Endurance exercise has been firmly established as a way to reduce diabetes and cardiovascular disease morbidity and mortality. The importance of mitochondria for both training performance and health underlies the significance of better understanding the factors that regulate exercise-induced adaptations in mitochondrial network dynamics. The effects on mitochondrial skeletal and cardiac muscle have already been well documented in the past. However, the specific impact of aerobic training on respiratory capacity in the vasculature remain to be established. Furthermore, the relationship between aerobic exercise and mitochondrial function in diabetic patients has yet to be investigated. We hypothesized that a long-term aerobic exercise intervention would enhance mitochondrial respiratory capacity in vascular smooth muscle cells. First, we investigated the effects of training in the vasculature of healthy mice (C57BL/6) and compared them to their sedentary counterparts. We found that exercise stimulates a rise in vascular mitochondrial content and respiratory capacity, especially complex I respiration (p < 0.05). However, when comparing diabetic trained mice to diabetic sedentary controls, it was found that aerobic training induced a downregulation in mitochondrial protein expression as well as a decrease in complex I respiration. In these experiments, our findings suggest that despite the demonstrated benefits of exercise, careful measures should be taken when exposing diabetic models that carry an inherently high risk of cardiovascular disease to prolonged exercise.


identifier: Burdick, Brittany  (2018) Modern Congolese Iconography of Patrice Lumumba in A Congo Chronicle.  Masters thesis, Concordia University.

abstract: This thesis focuses on the traveling exhibition A Congo Chronicle: Patrice Lumumba in Urban Art, mounted by The Museum of African Art, in New York, NY in 1999. The art in the show portrayed Patrice Lumumba (1925-1961) as an enduring heroic figure, who has now taken on religious significance since his death. Lumumba is cemented in the political discourse of an independent Africa, as such he is portrayed in A Congo Chronicle, as a symbol of national unity, political freedom and human rights; a cult of personality has arisen around Patrice Lumumba which can be seen through the continued use of his image as a political rallying point. This thesis examines the role art has played in solidifying Lumumba as a symbolic figure in the Congolese political landscape and the significance of popular paintings in the Congo. This thesis also explores how A Congo Chronicle is demonstrative of the importance of religious iconography in Congolese culture with imagery such as origin stories, Mami Wata and the representation of Lumumba as Christ. It further contends that in the Congo popular paintings focus not only on aesthetics but just as fundamentally on social discourse. By considering the examples of the origins of popular paintings, their place Congolese culture, the portrayal of Lumumba as a Christ-figure and the continued use of his image in political discourse it becomes apparent that the memory of Lumumba has taken on mythic proportions.


identifier: Kaur, Rupinder  (2018) Enterprise, project and workforce selection models for industry 4.0.  Masters thesis, Concordia University.

abstract:
Abstract
Enterprise, project, and workforce selection models for Industry 4.0.
Rupinder Kaur
The German federal government first coined industry 4.0 in 2011. Industry 4.0 involves the use of
advanced technologies such as cyber-physical system, internet of things, cloud computing, and
cognitive computing with the aim to revolutionize the current manufacturing practices.
Automation and exchange of big data and key characteristics of Industry 4.0. Due to its numerous
benefits, industries are readily investing in Industry 4.0, but this implementation is an uphill
struggle.
In this thesis, we address three key problems related to Industry 4.0 implementation namely
Enterprise selection, Project selection and Workforce selection. The first problem involves
identification of enterprises suitable for Industry 4.0 implementation. The second problem involves
prioritization and selection of Industry 4.0 projects for the chosen digital enterprises. The third and
last problem involves workforce selection and assignment for execution of the identified Industry
4.0 projects. Multicriteria solution approaches based on TOPSIS and Genetic Algorithms are
proposed to address these problems. Industry experts are involved to prioritize the criteria used for
enterprise, project and workforce selection. Numerical applications are provided.
The proposed work is innovative and can be useful to manufacturing and service organizations
interested in implementing Industry 4.0 projects for performance improvement.


identifier: Sameti, Mohammad ORCID: https://orcid.org/0000-0001-9365-0157 <https://orcid.org/0000-0001-9365-0157>  (2018) Development of an Optimization Model for Design and Planning of a Decentralized District Energy System.  PhD thesis, Concordia University.

abstract: This dissertation reports the development of a optimization model to help designing a tri-generation system for a given newly-built district with its consumers to satisfy the heating, cooling, and hot water demands featuring 4th generation district energy characteristics. The aim is to find the best way to select the equipment among various candidates (capacities), the pipeline network among the buildings, and their electrical grid connections. The objective function includes the annualized overall capital and operation costs for the district along with the benefits of selling electricity to the grid. The distributed energy supply consists of heating, cooling, and power networks, different CHP technologies, solar array, chillers, auxiliary boilers, and thermal and electrical storage. The performance of the model was evaluated for designing two different case under various scenarios: (i) a combined heat and power design, and (ii) a combined cooling and power design both carried out for the new part of Suurstoffi district situated in Risch Rotkreuz, Switzerland with seven residential and office complexes. For the combined heat and power design, the scenarios are defined based on the existence or non-existence of the distribution network (both heat and electricity) and the effectiveness of the storage systems. Allowing heat exchange among the buildings leads to 25% reduction in the total annualized cost and 5% reduction in emission compared to the conventional districts. Simultaneous heat and electricity exchange results in a higher reduction equal to 40% of the base scenario. Adding storage systems opens up an opportunity to lower both costs and emission even more and turns the district to a net-zero energy and energy plus districts. For the combined cooling and power design, the effectiveness of the network is analyzed together with the potential of feeding absorption chillers using the heat from the solar and non-solar energy sources. More than 67% of CO2 emission reduction is achieved through the hybrid heat and solar-driven arrangement.


identifier: Peralta, Laly Catalina  (2017) Commissioning truth: an exploration and assessment of an alternative approach to the production of truth in the aftermath of violence.  PhD thesis, Concordia University.

abstract: The first chapter of this thesis presents a review of the literature on the meaning of truth in the aftermath of violence. There, I argue that, historically, scholars have tried to justify the quest for truth in such circumstances (1) by reference to the benefits it brings, which is a type of instrumental justification; and (2) for its own sake, a type of intrinsic justification. Following my description and analysis of these two ideal typical accounts,  I present my own alternative approach to  truth in the aftermath of violence, which is a middle point between the two ideal types. This alternative approach provides a synthesis between knowing facts and telling testimonies; showing how the instrumental and intrinsic justifications of truth are actually closer than they appeared to be at first glance. The second chapter explores how this alternative approach could be materialized through a particular truth seeking mechanism such as a truth commission. The third chapter presents a methodological matrix, which systematizes my own vision of a bona fide truth commission. The matrix is made up of a series of consideratoions that are illustrated by analyzing two international experiences: the Truth and Reconciliation Commissions (TRCs) of South Africa and Sierra Leone. The fourth and last chapter seeks to demonstrate the utility of the proposed matrix by applying it to a particular case: the nascent truth commission of Colombia.


identifier: Church, Kathleen  (2018) Habitat Complexity and Behaviour: Personality, Habitat Selection and Territoriality.  PhD thesis, Concordia University.

abstract: Structurally complex habitats support high species diversity and promote ecosystem health and stability, however anthropogenic activity is causing natural forms of complexity to rapidly diminish.  At the population level, reductions in complexity negatively affect densities of territorial species, as increased visual distance increases the territory size of individuals.  Individual behaviour, including aggression, activity and boldness, is also altered by complexity, due to plastic behavioural responses to complexity, habitat selection by particular personality types, or both processes occurring simultaneously.  This thesis explores the behavioural effects of habitat complexity in four chapters.  The first chapter, a laboratory experiment based on the ideal free distribution, observes how convict cichlids (Amatitlania nigrofasciata) trade-off the higher foraging success obtainable in open habitats with the greater safety provided in complex habitats under overt predation threat.  Dominants always preferred the complex habitat, forming ideal despotic distributions, while subordinates altered their habitat use in response to predation.  The second chapter also employs the ideal free distribution to assess how convict cichlids within a dominance hierarchy trade-off between food monopolization and safety in the absence of a predator.  Dominants again formed ideal despotic distributions in the complex habitat, while dominants with lower energetic states more strongly preferred the complex habitat.  For both laboratory experiments, personality did not predict habitat preference.  The third chapter, a field study with juvenile Atlantic salmon (Salmo salar), tested whether stream restorations that increase habitat complexity will also select for particular personality traits, and we again found that complexity did not favour any particular personality types.  A broader range perspective regarding the effects of habitat complexity on behaviour was addressed in the fourth chapter via a meta-analysis on a wide range of territorial and non-territorial taxa.  Territoriality modified the effects of complexity on behaviour, likely due to the strong reliance of territorial species on visual cues.  Taken together, all four chapters demonstrate the high context dependency of the effects of complexity on behaviour.  Nevertheless, whether or not an individual is territorial emerged as an important predictor of how habitat complexity is likely to affect its behaviour.


identifier: You, Liang  (2018) How Disclosure Requirements Affect Investors and Sponsors: Evidence from Real Estate Crowdfunding.  Masters thesis, Concordia University.

abstract: The development of real estate crowdfunding in the past few years is attributed mostly to the passage of the JOBS Act. Although the SEC set disclosure requirements for crowdfunding, we notice there are still different levels of disclosure among platforms. In this thesis, we examine whether the different disclosure policies set by platforms affect projects’ proposed return and sponsors’ behavior. Due to the two-way causality relationship between disclosure requirements and proposed return, we use the simultaneous regression model to estimate. The empirical results show sponsors who launch projects on a platform with lower disclosure standard raise projects proposed returns as an attractive means. Sponsors who were supposed to prefer a less stringent regulation are surprisingly willing to disclose more information. This study is the first information asymmetry study on debt-based crowdfunding and provide implications for practice.


identifier: Fu, Shuai  (2018) Bayesian Learning of Asymmetric Gaussian-Based Statistical Models using Markov Chain Monte Carlo Techniques.  Masters thesis, Concordia University.

abstract: A novel unsupervised Bayesian learning framework based on asymmetric Gaussian mixture (AGM) statistical model is proposed since AGM is shown to be more effective compared to the classic Gaussian mixture. The Bayesian learning framework is developed by adopting sampling-based Markov chain Monte Carlo (MCMC) methodology. More precisely, the fundamental learning algorithm is a hybrid Metropolis-Hastings within Gibbs sampling solution which is integrated within a reversible jump MCMC (RJMCMC) learning framework, a self-adapted sampling-based MCMC implementation, that enables model transfer throughout the mixture parameters learning process, therefore, automatically converges to the optimal number of data groups. Furthermore, a feature selection technique is included to tackle the irrelevant and unneeded information from datasets. The performance comparison between AGM and other popular solutions is given and both synthetic and real data sets extracted from challenging applications such as intrusion detection, spam filtering and image categorization are evaluated to show the merits of the proposed approach.


identifier: D'Abate, Michael  (2018) Working With Children Having Multiple Disabilities: A Practical Guide.  Masters thesis, Concordia University.

abstract: The aim of this investigation is twofold: (1) to explore best practices with regards to teaching autistic and blind students in formal and informal learning environments (2) to create a practical guide for individuals who work with this target population. As a production and evaluation thesis equivalent, the methodology utilized for the data collection and evaluation is based on an action research model in which I collaborated with experts and practitioners in the field to acquire better knowledge and understanding of what techniques and strategies work best in teaching children that are multi-impaired. Employing an interactive/iterative approach, I used a combination of the initial questionnaire, interviews and literature searches to provide the content for the creation of a practical manual for field workers. This manual is comprised of a compilation of teaching techniques and strategies obtained from the data collected as well as examples of best practices as identified by those professionals who provided feedback. In the first phase of developing the manual, data were gathered and analyzed and a first draft was completed. An evaluation was then undertaken with experts in the field as well as others working with this population to review it and point out any inconsistent/missing information, lack of coherence, or problems with regards to how information was presented. These comments were then incorporated into a revised text that was submitted, once again, to experts in the field for a final summative evaluation in English and its multiple translations (French, Spanish, Quechua). The final edited manual will be published in the form of a practical guide that will be made available to professionals, volunteers and parents.


identifier: Waked, Louis ORCID: https://orcid.org/0000-0002-2799-7184 <https://orcid.org/0000-0002-2799-7184>  (2018) Analyzing TLS Interception in Middleware Network Appliances.  Masters thesis, Concordia University.

abstract:
Network traffic inspection, including TLS traffic, in enterprise environments is widely practiced. Reasons are primarily related to improving enterprise security (e.g., phishing and malicious traffic detection) and meeting legal requirements (e.g., preventing unauthorized data leakage, complying with laws such as the US Health Insurance Portability and Accountability Act, HIPAA). To be able to analyze TLS-encrypted data, network appliances implement a Man-in-the-Middle TLS proxy, by acting as the intended web server to a requesting client (e.g., a browser), and acting as the client to the actual/outside web server. As such, the TLS proxy must implement both a TLS client and a server, that can handle a large amount of traffic (preferably, in real-time). However, as protocol and implementation layer vulnerabilities in TLS/HTTPS are quite frequent, these proxies at least be as secure as a modern, up-to-date web browser (e.g., Chrome, Firefox), and a properly configured web server (e.g., an A+ rating in SSLlabs.com). As opposed to client-end TLS proxies (e.g., as implemented in several anti-virus products), the proxies in network appliances may serve tens to hundreds of clients, and any vulnerability in their TLS implementations can significantly downgrade an enterprise's security level.

To analyze TLS security of network appliances, we develop a comprehensive testing framework, by combining and extending tests from existing work on client-end and network-based interception studies. We analyze 13 representative network appliances over a period of more than a year (including multiple product versions, before and after notifying affected vendors, a total of 17 versions), and uncover several security issues regarding TLS version and certificate parameters mapping, CA trusted stores, private keys, and certificate validation tests. For instance, we found that four appliances perform no certificate validation at all, three use pre-generated certificates, and 11 accept certificates signed using the MD5 algorithm, exposing their end-clients to MITM attacks. Our goal is to highlight the risks introduced by widely-used TLS proxies in enterprise and government environments, potentially affecting many systems hosting security, privacy, and financially sensitive data.


identifier: Boulanger, Ann Marie  (2018) Translating Culture: Denise Bombardier’s Dictionnaire amoureux du Québec.  Masters thesis, Concordia University.

abstract:
Abstract

Dictionnaire amoureux du Québec, by Denise Bombardier, is a collection of subjective essays about the features that make Quebec unique on the North American landscape, and that distinguish it from its European counterpart, France. Throughout the book, the author makes reference to French words, grammar and language usage, and also employs cultural references that are specific to Quebec and/or France. In this thesis, I translate select excerpts from the Dictionnaire. The thesis also examines the factors that might make an Anglophone reader less likely to understand these references if they were to be left intact in an English translation, with no attendant explanations. Chief among these factors are a lack of French language proficiency and a deficient knowledge of the source culture. It then discusses the methods and strategies that I employed in my translation of Dictionnaire amoureux du Québec to address these linguistic and cultural challenges, in an attempt to bridge the lexicultural gap between the source-text reader and the target text reader.

Résumé

Dictionnaire amoureux du Québec, de Denise Bombardier, est un recueil d’essais subjectifs abordant diverses particularités qui rendent la Belle Province unique dans le paysage nord-américain et la distingue de son homologue européenne, la France. Au fil du livre, l’auteure s’intéresse à la langue française – mots, grammaire et usage – et emploie des références culturelles propres au Québec et à la France. Dans le cadre de ce mémoire, je traduis des extraits choisis du Dictionnaire. Le mémoire se penche également sur les facteurs qui pourraient faire en sorte qu’un lecteur anglophone comprenne moins aisément ces références si elles étaient laissées intactes dans une traduction anglaise, sans autres explications. Un manque de maîtrise de la langue française et une connaissance insuffisante de la culture d’origine sont deux de ces principaux facteurs. La mémoire aborde ensuite les méthodes et les stratégies que j’ai employées dans ma traduction du Dictionnaire amoureux du Québec pour relever ces défis linguistiques et culturels, dans une tentative de combler le fossé lexiculturel entre le lecteur du texte source et celui du texte cible.


identifier: Stong, Jesse  (2018) Durational Performance as Pedagogy: 200 Hours of Queer Puppets, or ‘Real Men Don’t Play with Puppets’.  Masters thesis, Concordia University.

abstract: A puppetry and object-performance experiment that explores extreme forms of durational performance, questioning how these intensive creative undertakings carry the potential to bring an artist as well as audiences outside of their habitual ways of being. Theatre-based artist and educator Jesse Stong searches for dynamic ways to both learn and teach the craft of performance from across mediums. With the focus of utilizing duration as a tool for transformation, he shares reflections from his 200-hour non-stop puppet project, developing performance art pedagogy, exploring queer time and space, and understanding the uncanny art of breathing life into the inanimate world.


identifier: Vadaga, Kiran  (2018) Task-set Inhibition And Aging: New Insights From The Dual Mechanisms Control Theory.  PhD thesis, Concordia University.

abstract: With the increasing proportion of older adults in the population, the maintenance of autonomy in everyday functioning is of growing importance. To this end, cognitive aging researchers have identified executive functions, including attentional switching, inhibition, and updating, to be key factors in everyday functioning. A current model of cognitive control, Dual Mechanisms of Control theory (DMC; Braver, Gray, & Burgess, 2007) postulates two basic mechanisms. Proactive control involves goal maintenance and conflict resolution based upon preceding cue information, whereas reactive control resolves conflicts based upon immediate stimulus characteristics. The prior research indicates age-related variance in executive functions is related to age-related declines in proactive control. The overall aim of this dissertation is to examine DMC processes in one particular executive function, task switching, which is essential for efficient multi-tasking and entails task-set inhibition (TSI) to smoothly transition from one task to the next (Mayr & Keele, 2000; Mayr, 2001). Previous work suggests that TSI requires proactive control (Mayr, 2007), which declines with aging, yet the empirical support for age differences in TSI is mixed. Therefore, in Study 1, healthy young (n = 28) and older adults (n = 22) were compared on a task switching paradigm, in which TSI was assessed under high (flanker trials) and low (unflanked trials) reactive control task contexts. The results show age-equivalent TSI effects in low reactive control, but young adults showed larger TSI in high reactive control. In Study 2 (Expt. 1: nYA = 25, nOA = 25; Expt. 2: nYA = 25, nOA = 25), age-related TSI effects were examined across four conditions that varied along a proactive-reactive control continuum. A key aspect of this design was that the four task contexts were intermixed, thereby compelling participants to adopt a global control strategy that was either reactive (Expt. 1) or proactive (Expt. 2). In line with Study 1, the overall results of Study 2 indicate that TSI effects are observable in reactive control task contexts. Additionally, young and older adults showed differential modulation of the dual control processes to match the global task context. In Experiment 2 when the task context was more proactive, older adults exhibited more TSI than young adults. Taken together, these results suggest that age-related TSI effects are contingent on the age-related utilization of the dual control processes, which in turn are influenced by the global task context.


identifier: Houdeib, Ramzi  (2018) Age-related differences in Cognitive Plasticity of Executive Control Mechanisms: Exploring Transfer Effects Following iPad-based Dual-Task and N-Back Training.  Masters thesis, Concordia University.

abstract:
Recent literature suggests that executive function (EF) is not a unitary construct but one that involves many executive control mechanisms (ECM), such as updating and divided attention. Some posit that cognitive training helps improve EF in younger (YA) and older (OA)
adults, but transfer effects, which refer to improvements in an untrained task, remain somewhat limited. This study examined the age-related differences in transfer effects following cognitive
training of ECM by comparing two training paradigms designed to involved distinct ECM. Thirty-three YA and 42 OA were randomly assigned to a n-back (NB) or dual-task (DT) training group for three weeks. Pre/post-training assessment involved the trained task and their respective transfer tasks. Age was used as a between-subject factor, while session (pre/post) and task condition (low, medium, high load), as within-subjects factors. Both training groups improved on their respective trained tasks and transfer task involving the same ECM (near-transfer). Transfer effects were also observed in a transfer task involving a different ECM (far-transfer). The DT group improved in the DT-transfer and one of the two NB tasks. The NB group improved in the NB-transfer and both DT tasks. Age-related differences in transfer were observed for the DT group, with the dual-task cost and 3-back accuracy of YA improving on the DT-transfer task and N-back task respectively, while OA only improved on the 1-back and 2-back. Overall, the results suggest that OA and YA benefited from ECM training and that these benefits generalized to untrained tasks tapping the same and other ECM.


identifier: Badawy, Ahmed  (2018) An Evaluation Model for Competitiveness Index of Construction Companies.  Masters thesis, Concordia University.

abstract:
The construction sector continues to experience significant challenges brought by new techniques and technologies. There is a dire need for construction companies to address critical issues concerning changing environmental conditions, construction innovations, market globalization and many other aspects, thereby enhancing their competitiveness edge. The existing literature shows that competitiveness approaches do not address current challenges. Thus, the primary goal for this research is to develop an evaluation model that would consider all essential factors in determining the competitiveness index of construction companies and so aid in their growth and development.

In this research three new pillars (3P) for competitiveness are introduced: (1) Non-Financial Internal Pillar; (2) Non-Financial External Pillar; and (3) Financial Pillar. This concept can help construction companies manage short-term and long-term strategic plans and goals. The 3P includes 6 categories and 26 factors incorporated and defined by the assessment model for measuring competitiveness. This research also rests upon a questionnaire that was sent globally to generate two sets of information which are the factors affiliated thresholds and the weights for the identified factors using the Fuzzy Analytical Network Process (FANP) which was required to reduce the uncertainty inherited from the judgment of the respondents and the factors affiliated thresholds. Preference Ranking Organization Method for Enrichment Evaluation (PROMETHEE) technique was implemented using the weight of factors and their associated thresholds as an input. PROMETHEE was then used as a ranking technique to rank any given construction company by determining its competitiveness index.
The proposed evaluation model was validated through five cases studies that reveal its potential of illustrating detailed analysis with respect to the competitiveness ability of construction companies. A graphical user interface was developed for providing a competitiveness index for any construction company and rank companies relative to one another. It is anticipated that the proposed evaluation model can be used in decision making process by all parties involved in construction projects. Contractors can use the evaluation model in making better decisions regarding the markup values. Employers can also use the same model in the evaluation process of contractors.


identifier: Bakhshi, Mahdi  (2018) Registration and Display of Functional Data.  Masters thesis, Concordia University.

abstract:
Functional data refer to data which are in the form of functions or smooth curves that are assessed at a finite, but large subset of some interval. In this thesis, we explore methods of functional data analysis, especially curve registration, in the context of climate changes in a group of 16 cities of the United States. In the first step, spline functions were developed in order to convert the raw data into functional objects. Data are available in function forms, but the mean function which was obtained by the unregistered curve fails to produce a satisfactory estimator. This means that the mean function does not resemble any of the observed curves. A significant problem with most functional data analyses is that of misaligned curves.
Curve registration is one method in functional data analysis that attempts to solve this problem. In the second step, we used curve registration method based on "landmarks alignment" and "continuous monotone registration" in order to construct a precise measurement of the average temperature. The results show the differences between unregistered data and registered data and a significant rise of the temperature in U.S. cities within the last few decades.


identifier: Rahimi, Farnoosh  (2018) Support Vector Machines with Convex Combination of Kernels.  Masters thesis, Concordia University.

abstract: Support Vector Machine (SVMs) are renowned for their excellent performance in solving data-mining problems such as classification, regression and feature selection. In the field of statistical classification, SVMs classify data points into different groups based on finding the hyperplane that maximizes the margin between the two classes. SVMs can also use kernel functions to map the data into a higher dimensional space in case a hyperplane cannot be used to do the separation linearly. Using specific kernels allows us to model a particular feature space, and a suitable kernel can improve the SVMs' performance to classify data more accurately. We present a method to combine existing kernels in order to produce a new kernel which improves the accuracy of the classification and reduce the process time. We will discuss the theoretical and computational issues on SVMs. We are going to implement our method on a simulated data-set to see how it works, and then we will apply it to some large real-world data-sets.


identifier: Foster, Katherine  (2018) The Effects of Object Familiarity on Fourth-Graders’ Performance on Equal Sharing Fractions Problems.  Masters thesis, Concordia University.

abstract: A study was conducted that compared students’ solutions to word problems that differed by the degree to which they were grounded in realistic settings. In a repeated measures design, fourth-graders (N=115) solved three types of equal sharing problems: grounded problems, containing familiar objects, such as brownies; semi-grounded problems with less familiar objects, such as lengths of rope measured in centimeters; and idealized problems, containing non-words (e.g., “porams”). No difference was observed between grounded and idealized problems, but both problem types yielded superior performance relative to semi-grounded problems. Prior knowledge of fractions and multiplicative structures was associated with greater performance overall. One implication is that only partial familiarity with problem contexts may activate irrelevant schemas and hinder problem-solving performance.


identifier: Attarkashani, Anahid  (2018) Resource Allocation in Relay Networks.  PhD thesis, Concordia University.

title: Resource Allocation in Relay Networks

abstract:
Demand for high data rates is increasing rapidly, due to the rapid rise of mobile data traffic volume. In order to meet the demands, the future generation of wireless communication systems has to support higher data rates and quality of service. The inherent unreliable and unpredictable nature of wireless medium provides a challenge for increasing the data rate. Cooperative communications, is a prominent technique to combat the detrimental fading effect in wireless communications. Adding relay nodes to the network, and creating s virtual multiple-input multiple-output (MIMO) antenna array is proven to be an efficient method to mitigate the multipath fading and expand the network coverage. Therefore, cooperative relaying is considered as a fundamental element in the Long Term Evolution (LTE)-Advanced standard.
In this thesis, we address the problem of resource allocation in cooperative networks. We provide a detailed review on the resource allocation problem. We look at the joint subcarrier-relay assignment and power allocation. The objective of this optimization problem is to allocate the resources fairly, so even the cell-edge users with weakest communication links receive a fair share of resources. We propose a simple and practical algorithm to find the optimal solution. We assess the performance of the proposed algorithm by providing simulations. Furthermore, we investigate the optimality and complexity of the proposed algorithm.
Due to the layered architecture of the wireless networks, to achieve the optimal performance it is necessary that the design of the algorithms be based on the underlying physical and link layers. For a cooperative network with correlated channels, we propose a cross-layer algorithm for relay selection, based on both the physical and link-layer characteristics, in order to maximize the linklayer throughput. The performance of the proposed algorithm is studied in different network models. Furthermore, we investigate the optimum number of relays required for cooperation in order to achieve maximum throughput.
Buffering has proven to improve the performance of the cooperative network. In light of this, we study the performance of buffer-aided relay selection. In order to move one step closer to the practical applications, we consider a system with coded transmissions. We study three different coding schemes: convolutional code, Turbo code, and distributed Turbo code (DTC). For each scheme, the performance of the system is simulated and assessed analytically. We derive a closed form expression of the average throughput. Using the analysis results, we investigate the diversity gain of the system in asymptotic conditions. Further, we investigate the average transmission delay for different schemes.


identifier: Tremblay Lamontagne, Nora  (2018) Ageing and materialities: A study of the practice of weaving at Cercle de Fermières.  Masters thesis, Concordia University.

abstract: This thesis examines the weaving practices of the Cercle de Fermières, a century-old community of older women, in light of Actor-Network Theory (ANT) (Akrich, 1987; Latour, 2006) and feminist theories of technologies (Haraway, 2004; Wajcman, 2007). Who and what is included in this “Cercle?” How do the affordances of technologies and materials contribute to the creation of necessities and forms of interaction within the organization? What happens when both humans (weavers) and non-humans (looms, thread, buildings) actors “age together?” I examine how the dynamic assemblage pertaining to the practice of weaving influences the organizational structure of the Cercle and contributes to the creation of associations and entanglements. Five vignettes describe life at the weaving Cercle and the roles of actors and ageing in this organization. A relational understanding of age and ageing, essential components of this analysis, allows to notice their uneven effects across the assemblage. While ageing has a profound impact on what it means to be a weaver, a centenarian organization or an ageing technology, ANT provides few theoretical tools to comprehend these entangled issues. This is addressed in the discussion section of this thesis. The empirical data comes from interviews and participant observation of two Cercles de Fermières : one in Montreal and one in Baie Saint-Paul. Interviews were conducted with five Fermières, aged 80 years old or more.


identifier: Bryans, John  (2018) Type Cast(e)-ing: Subversion and conformity in the embodied identities of fat male film and television actors.  Masters thesis, Concordia University.

abstract: Typecasting of actors in film and television based on physical appearance is common as it facilitates the narrowing of an immense talent pool (Zuckerman et al., 2003). Despite its apparent advantages, however, this categorization process has been criticized for participating in the reproduction of heteronormative standards (Dean, 2008). Research on fatness and masculinity in film is scant and tends to focus on issues of representation (Fouts & Vaughan, 2002). Very little research examines the lived experiences of those men whose work is to perform fatness onscreen. Because of the demands of their work, men in the performing arts are uniquely positioned to offer insight into how the fat male body is constructed in light of contemporary shifting ideals of the male body in popular culture (Morrison & Halton, 2009). In many cases, these men are called upon to embody fat masculinities that have the capacity to both subvert and reinforce hegemonic masculinity (Connell, 2005; Buchbinder, 2008; Benson-Allott, 2012). In light of the reductive nature of acting roles for fat men (Gilman, 2004), this research examines how fat male actors negotiate their personal and professional identities and, in doing so, disrupt or conform to heteronormative constructions of the body in popular culture. This thesis draws on findings from a video research project in which fat male film and television actors were tasked with co-creating their own narratives by discussing their experiences as professional actors vis à vis participant-produced video diaries.


identifier: Mahmud, Ashraf  (2018) Dopamine Transients in the Ventral Tegmental Area Attenuate Aversive Prediction Error.  Masters thesis, Concordia University.

abstract: Prediction-error, the discrepancy between real and expected outcomes, drives associative learning. It is best exemplified in the blocking paradigm. In blocking, impairment in learning about the predictive relation between a cue (e.g., a clicker) and an outcome (e.g. footshock) is observed when this learning takes place in the presence of a good predictor (e.g. a light) for the same outcome. Small prediction-error generated by the light leads to impairment in learning about the clicker-footshock relationship. The mere presentation of the two stimuli in compound in the absence of pre-training of one of those stimuli does not yield blocking. That is, in the so-called overshadowing control condition, the clicker is presented in compound with the light that was not previously associated with the footshock. This arrangement leads to robust learning about the clicker due to the presence of a maximum prediction-error. Dopamine (DA) in the ventral tegmental area (VTA) has been implicated in reward prediction-error (RPE). Evidence suggests an opposing role of DA in fear and reward. Here we undertook several experiments aimed at elucidating the role of VTA DA neurons in aversive prediction-error (APE). We used a powerful behavioural and theory-driven approach by combining blocking and the corresponding overshadowing control in the context of aversive (fear) learning along with optogenetics. We used the Th-cre+/- rats in order to exercise fine temporal control over VTA DA neurons during aversive learning. Taken together, our results provide evidence that optical stimulation of VTA DA neurons and their terminals in the nucleus accumbens (NAc) at the time of expected shock augmented the blocking effect by attenuating APE and further impaired learning about the blocked cue. We did not observe such an effect in the overshadowing control nor many neural control groups.


identifier: khazaeli, shida  (2018) Intelligent one-point damage localization of an isotropic surface pipeline using Guassian Process regression.  Masters thesis, Concordia University.

abstract:
Pipelines are subjected to many damaging agents, such as, earthquake, ground movement, and
aging which are responsible for important financial expenses. Structural Health Monitoring (SHM)
of civil structures using arrays of sensors is promising such that data form the monitoring systems
enable us to trace the structural anomalies and performance for early treatments. The need for
introducing faster and intelligent methods has helped researchers propose novel approaches for such
monitoring procedures. In this study a new method is introduced for monitoring of surface pipelines
used primarily for oil and gas. The framework takes the advantage of Gaussian Process Regression
Method (GPRM) to create a probabilistic predictive model for damage detection and the subsequent
localization of the defect. To this end, an isotropic pipeline is modeled numerically and validated with
an experimental setup. Afterwards, the model is extended to the real-life application to establish
a meta model. Damages are introduced as small holes at different locations (one at each time).
The GPRM is used to map the system responses to the selected statistical features which are
utilized as indicators for the existence of the damages and their locations. GPRM reveals more
promising results compared with conventional regression analysis. It considers the uncertainties due
to lack of observation. In addition, it is an updatable approach with having local effects on the
model. In another words, it affects the model in the vicinity of new observations. Moreover, among
selected statistical features, number of peaks greater than or equal to 20% and 60% of the maximum
peak values show better results corresponding to damage localization. Also the curve length and
correlation coefficient of the system response (induced signal) are found to be efficient for damage
detection. The novel method has been validated with filed measurements and experimental data
and found to work efficiently.


identifier: Heidari Khazaei, Fereshte  (2018) TEACHING NATURE OF SCIENCE (NOS) WITH STUDENT-CENTRED INSTRUCTION.  Masters thesis, Concordia University.

abstract:
The Nature of Science (NOS) covers the aim, development, criticism and explanation of
science (Abd-El-Khalick, 2001; Hickey, 2005; Lederman, 1992; Matthews, 1994; McComas,
2004). This study examines the impact that studying philosophy and history of science has on
undergraduate students’ views about the NOS. Studying philosophy and history of science can
also enhance students’ critical thinking skills. It helps students to understand what science is,
how to characterize the nature of its practitioners’ activities, and what is the significance of the
whole enterprise.
Having students study scientific concepts through the eyes of philosophers and historical
scientists actively engages them in the process of inquiry and challenges them to increase their
understanding of the NOS.
This study showed that studying philosophy and history of science in a student-centered
classroom had a strong influence on students’ views about the NOS in that many students
changed their views about the NOS. Students who did not change their over-all perception gave
much clearer expositions of their views.


identifier: Patel, Shaneha  (2018) Examining the Quality of Storybook Reading Sessions Between Parents and Children.  Masters thesis, Concordia University.

abstract: The home environment is an important contributor to children’s literacy experiences. One activity that is frequently investigated is parent-child storybook reading. However, despite the extant research, the quality of these book-reading interactions has often been overlooked. Therefore, the present study examined the quality of book-reading sessions between 60 parent-child dyads recruited from local schools in Montréal, Canada. Storybook reading sessions were recorded and behaviours were coded for types of talk (immediate, non-immediate, illustration production, and print referencing) and engagement (behaviours showing enjoyment in the reading session). The results of hierarchical multiple regressions demonstrated that parents’ non-immediate talk and engagement accounted for unique variance in children’s non-immediate talk and engagement, above and beyond children’s own behaviours. Parallel regressions demonstrated that children’s non-immediate talk and engagement accounted for unique variance in parents’ non-immediate talk and engagement, above and beyond parents’ own behaviours. These results emphasize the reciprocal role that both parents and children play during storybook reading activities. Implications for parents’ practises are discussed.


identifier: Shahbazian, Ani  (2018) Degrees of Separation.  Masters thesis, Concordia University.

title: Degrees of Separation

abstract: Degrees of Separation is a collection of four short stories exploring one character’s quest to return home through an unconscious process of refraction and destruction of self. The stories explore themes such as home, selfhood, innocence, love, loss, imagination, and self-destruction. In “Accidental Death,” faced with an experience of loss that she is emotionally unable to comprehend, Liz splits herself into three, projecting her fear onto a shadow, and her pain onto a bird which she kills, marking her first exile from self. In “Shadow Play,” Liz is trapped in a painful process that all at once mimics and destroys her sense of home. She projects her weakness on a proxy, which becomes a target for her anger against herself, and snaps out of the cycle only when she acknowledges the effect of her destructive power on the proxy, but not on herself. In “Cyrano,” Liz continues to search for home, projecting her desire to be saved onto a woman, and unconsciously ignoring her pain to hold onto her at all costs. Liz also projects her innocence onto a child, and experiences something close to love in her effort to protect it from herself. In “Fourth Degree Murder,” Liz has repressed her pain by erasing its traces from the visible world. She projects her fear of destruction on a man, which she instrumentalizes to violate herself. In the end, though Liz is literally faced with her own image, she fails to recognize it as the locus of home.


identifier: MacDonald, Thomas  (2018) Pirates, Hydras, Trolls, and... Authors? On the Authorial Capacities of Digital Media Piracy.  Masters thesis, Concordia University.

abstract: In this thesis, I undertake a positive analysis of digital media piracy to examine the movement’s authorial capacities. Proposed by James Meese as a way of looking beyond the traditional “piracy is theft” framework, this perspective offers new insights about how the increasingly mundane act of downloading and sharing media files can incite social change. I begin by examining what it means to be a digital media pirate, and how that question is part of the construction of the piracy movement. In the second chapter, I explore the complex relationship between piracy and information capitalism, highlighting how piracy arises from within information capitalism. In the third chapter, I look to how moral panic discourse has been used to demonize pirates, but also how this process has been appropriated by pirates to circulate counter-hegemonic discourse. In the fourth chapter, I examine how pirates are the authors of alternative ethical criteria within private filesharing communities, and how pirates mobilize moral and ethical discourse to push back against attempts to impede their ability to pursue a good piratical life. The final chapter of this thesis takes up the ethnographically rich moment of the Kickass Torrents shutdown in July 2016. Looking at the shut down as an event that like digital media piracy is both meaningful yet mundane, we see how pirates, though contesting romanticized and naturalized norms of property and authorship, push for a new form of authorship constituted by p2p communication in online spaces. Through these perspectives on the piracy movement in the summer of 2016, I argue that through the agglomerated effects of individual acts of piracy, the broader piracy movement radically changes the ways we understand and engage with cultural media objects.


identifier: Forbes, Christopher J.  (2018) Oswaldo: A Semantic Web Enabled Approach for Identifying Open Source License Violations.  Masters thesis, Concordia University.

abstract: Open source license violations are numerous, multifaceted, and pose significant risk to developers and companies in the form of litigation, sometimes resulting in millions in dollars in damages or settlements. Free/Libre and Open Source Licenses utilize copyright law and are written in legalese, which is often outside the scope of a developer’s expertise. Software Engineers commit violations of these licenses’ terms and conditions easily and often unknowingly. Consequently, increased knowledge, better tools, and sound processes to detect and prevent license violations are extremely important. This work is an investigation in the types of potential license violations that are committed, through direct and transitive dependency hierarchies in hundreds of thousands of real-world software projects. This thesis contributes a novel approach, entitled Oswaldo, that defines and detects three types of license conflicts: Type 1 Simple Violation, Type 2 Embedded Violations, Type 3 Compound Violations. Unidirectional compatibility/incompatibility relationships of major licenses are modelled. Ontologies and Linked Data are advantageously exploited to detect transitive violation Types 2 and 3, as well as the direct violation Type 1. This thesis also reports initial evaluations of these three types of license violations found in the Maven repository.


identifier: Tran, Patricia ORCID: https://orcid.org/0000-0003-3948-3938 <https://orcid.org/0000-0003-3948-3938>  (2018) Microbial life under ice: Metagenome diversity and in situ activity of Verrucomicrobia in seasonally ice‐covered lakes.  Masters thesis, Concordia University.

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abstract: Northern lakes are ice‐covered for a large part of the year, yet our understanding of microbial diversity and activity during winter lags behind that of the ice‐free period. In this study, we investigated under‐ice diversity and metabolism of Verrucomicrobia in seasonally ice‐covered lakes in temperate and boreal regions of Quebec, Canada using 16S rRNA sequencing, metagenomics and metatranscriptomics. Verrucomicrobia, particularly the V1, V3 and V4 subdivisions, were abundant during ice‐covered periods. A diversity of Verrucomicrobia genomes were reconstructed from Quebec lake metagenomes. Several genomes were associated with the ice‐covered period and were represented in winter metatranscriptomes, supporting the notion that Verrucomicrobia are metabolically active under ice. Verrucomicrobia transcriptome analysis revealed a range of metabolisms potentially occurring under ice, including carbohydrate degradation, glycolate utilization, scavenging of chlorophyll degradation products, and urea use. Genes for aerobic sulfur and hydrogen oxidation were expressed, suggesting chemolithotrophy may be an adaptation to conditions where labile carbon may be limited. The expression of genes for flagella biosynthesis and chemotaxis was detected, suggesting Verrucomicrobia may be actively sensing and responding to winter nutrient pulses, such as phytoplankton blooms. These results increase our understanding on the diversity and metabolic processes occurring under ice in northern lakes ecosystems.


identifier: Ma, Wen ORCID: https://orcid.org/0000-0003-3040-0526 <https://orcid.org/0000-0003-3040-0526>  (2018) Biofouling Mitigation of Reverse Osmosis (RO) Membranes via Surface Modification with Nanoparticles and Polymer Brushes.  PhD thesis, Concordia University.

abstract:
The reverse osmosis (RO) filtration process, which uses semi-permeable membranes to achieve selective mass transport, has become the most versatile and efficient technique to produce fresh water from saline water and wastewater sources. A major challenge facing the widespread application of RO technology is membrane biofouling which is caused by the deposition and multiplication of microorganisms on the surface of the membranes required for the filtration process. Biofouling not only deteriorates membrane materials but also adds an energy burden to the system, increasing the operational cost of the RO technique. Modifying membrane surfaces with antibacterial materials is an effective technique to prevent the growth of biofilms while maintaining the original water purification capabilities of the membrane.
In this study, three district types of membrane-surface modifications were proposed as potential methods for mitigating biofouling on the RO membrane: (i) bacteria/biofilm-“defending” strategy: coating with zwitterionic and low-surface-energy polymers to prevent microorganism/protein deposition; (ii) bacteria/biofilm-“attacking” strategy: anchoring CuNPs to inhibit the propagation of microorganisms and (iii) combined bacteria/biofilm-“defending and attacking” strategy:  grafting polymers and natural antibiofouling materials to not only prevent foulant deposition but potentially inhibit biofilm formation.
Hydrophilic compounds (polysulfonbetain, PSB) and low surface energy polymers (polydimethylsiloxane, PDMS) were grafted in combination to the membrane to control biofouling via the bacteria/biofilm-“defending” strategy. Results showed that surface hydrophilicity is critical for the deposition of bacteria and protein. Combining functionalization of different fouling-resistant materials (PDMS and pSB) achieved an enhanced antibiofouling performance.
CuNPs were proposed as a cost-efficient and quality-competitive material for fabricating antibiofouling membranes with bacteria-“attacking” functions. CuNPs modified membranes exhibited bacterial inactivation comparable to the widely used silver NPs. The multiple layers of CuNPs coating on surface mitigated the permeate flux decline caused by biofouling and the flux of the modified membrane was 20% higher than the control under the same experimental conditions.
The fouling resistant membrane with a combined bacteria/biofilm-“defending” and -“attacking” function was fabricated by grafting a fouling-resistant polymer (poly(sulfobetaine methacrylate), PSBMA) and a biofilm inhibiting amino acid (poly methacryloyl-L-Lysine, PLysMA) to the membrane via a polymer length controlling technique, electron transfer-atom transfer radical polymerization atom (ARGET-ATRP). When the defending moieties (PSBMA) were predominant on the exposed top of surface with the biofilm inhibiting material (PLysMA) underneath, the membrane significantly mitigated the flux decline caused by bacterial deposition and biofilm formation (50% higher than the control). Furthermore, complete flux recovery was observed on the former after two cycles of “fouling-cleaning”, while the control membrane only maintained 94% of initial flux under the same condition.
This study proposes cost-effective modifiers (CuNPs and PLysMA) for the fabrication of anti-biofouling membranes, enriches the knowledge around the application of GO in modification of anti-biofouling membranes and proposes controllable functionalization methods for the development of antibiofouling membranes. The strategies proposed in this study contribute to the investigation of novel anti-biofouling membranes and the development of facile membrane modification methods, which can further broaden the applicability of membrane processes in wastewater reclamation and increase the future fresh water supply.


identifier: Vega, Sergio  (2018) Nearby forest habitat increase wild bee diversity in managed blueberry fields.  Masters thesis, Concordia University.

abstract: Global declines in managed honey bee populations have been a major concern for the agricultural sector. Similarly, continued habitat fragmentation and degradation of natural and semi-natural habitats have been identified as a major threat for wild bee communities. In Canada, wild bees and managed honey bees both pollinate blueberries (Vaccinium spp.), which is the largest fruit commodity and accounts for a market value of over $250 million per year. I assessed whether the amount of forest land cover surrounding highbush blueberry fields affects the diversity of wild bee pollinators. Specifically, I sampled wild bee communities in 18 blueberry fields during the blooming period in Monteregie, Quebec, Canada. Sampling consisted of placing pan trap triplets and direct observation of flower visitations on blueberry bushes. I also quantified the surface area representing natural, semi-natural, and anthropogenic landscape cover in a radius of 500m, 1000m, and 2000m around each field. Then I related wild bee abundance and richness to forest land cover proportion. The proportion of forest land cover varied along different scales from 0.00% to 50.8% at 500m radius and from 0.17% to 62% at 2000m radius. Wild bee abundance and richness were positively related to the proportion of the forest habitat adjacent to the crop field. Moreover, the strength of these relationships increased with spatial scale.  By understanding how the nearby natural habitat benefits wild bee diversity in highbush blueberry fields and, ultimately, pollination services, conservation efforts can focus on land cover features to help halt the decline in bee diversity.


identifier: Morin-Lessard, Elizabeth  (2018) Speech Disfluencies: Their Role in Comprehension and Word Learning.  PhD thesis, Concordia University.

abstract:
One of the most extraordinary aspects of human development is how children acquire their language(s) by listening to spontaneous speech. Perhaps more remarkably, they do so even though speech is often highly disfluent. To better understand how language acquisition unfolds, this dissertation explored the effects of speech disfluencies on real-time word comprehension and on word learning for listeners from different language backgrounds and levels of expertise: monolingual children, bilingual children, and bilingual adults.

Manuscript 1 reports two word comprehension studies, looking at the ability of children and adults to use disfluencies to predict whether a speaker will name a novel or a familiar object. This ability was investigated by presenting sentences with disfluencies in listeners’ native and non-native language(s). Study 1 tested 32-month-old monolingual and bilingual children, and Study 2 tested bilingual adults. Results from Studies 1 and 2 indicate that listeners looked more at the novel than the familiar object upon hearing a disfluency, irrespective of participants’ language experience, and whether the disfluency was in participants’ native language(s). Importantly, the results suggest that listeners might attend to a speaker’s uncertainty more than the particular realization of the disfluency.

Manuscript 2 investigates the impact of speech disfluencies on novel word learning in monolingual and bilingual 32-month-old children. We considered two contrasting possibilities: (1) Disfluencies will facilitate novel word learning, since listeners direct looks to novel objects upon hearing a disfluency, versus (2) disfluencies will hinder novel word learning, since they signal a speaker’s uncertainty about an object’s label. The results indicate that disfluencies may hinder novel word learning: Children did not learn the novel words following disfluencies, nor the novel words following fluent speech. Though somewhat inconclusive as children did not learn words in either case, these results suggest that children’s word learning may be hindered when a speaker is disfluent.

Together, the results from the two manuscripts in this dissertation suggest that speech disfluencies are a double-edge sword: they can be helpful for making predictions during real-time comprehension, but could hinder word learning. These findings have important implications for understanding the role of speech disfluencies in language acquisition.


identifier: Germain, Ricky  (2018) The Morphosyntactic Origins of the Definite Adjectives in Old Lithuanian.  Masters thesis, Concordia University.

abstract:
The Lithuanian definite adjective construction originates from the suffixation of the Proto-
Indo-European *ye/o- relative pronoun to simple form adjectives (baltas vs. baltasis). Although
this category has formal parallels in virtually every member of Balto-Slavic, the facts
of its historical development are largely lost due to the relatively late attestation of both
Baltic and Slavic. Evidence from Old Lithuanian, however, suggests that grammaticalization
of the definite marker as adjectival morphology occurred exceptionally late, likely after the
split of Baltic and Slavic. Furthermore, Old Lithuanian shows signs of the definite marker
also having encliticized to nominal modifiers, most often found in the locative case (t˙evas
dangujejis, father in heaven).

The present thesis explores the implications of how the relative pronoun, and by extension
relative clauses in Proto-Indo-European, could undergo development to form the adjectival
construction of Modern Lithuanian. First, the analysis motivates the origins of the definite
marker from the domain of syntax by relying on establishing a structural parallel in the historical
development of the reflexive particle si— known to have been a Wackernagel’s Law
clitic by comparison with facts of Slavic—with that of the deverbal adjectives of Old Lithuanian
when taken in their definite form (pajoprasto vs prastojo, nusiprausti vs praustis). Both
these particles’ complementary distribution as prefix and suffix suggests earlier sensitivity to
elements of clausal syntax. On this evidence, a reconstruction for Proto-Balto-Slavic clauses
is posited and the internal evidence is further corroborated by the use of the comparative
method on Balto-Slavic and Indo-Iranian, the latter still attesting the Proto-Indo-European
relative pronoun in its original use.

Finally, the early development of the predecessor to the definite marker jis is explored for
the period from Proto-Indo-European up until latest Proto-Balto-Slavic. Using the history
of the Iranian ezafe as a case study for a parallel development in early Balto-Slavic, a careful
account is given of the reanalysis of adjectival and nominal predicates in relative clauses to
justify the formation of both definite adjectives and dangujejis type construction.


identifier: Ruhi, Ruhi ORCID: https://orcid.org/0000-0001-7181-3816 <https://orcid.org/0000-0001-7181-3816>  (2018) New Kernels For Density and Regression Estimation via Randomized Histograms.  Masters thesis, Concordia University.

abstract: In early 20’s,  the first person to notice the link between Random  Forests  (RF)and  Kernel  Methods, Leo  Breiman(Breiman,  2000), pointed out that  RandomForests grown using independent and identically distributed random variables in the tree construction is equivalent to kernels acting on true distribution.  Later, Scornet (Scornet, 2016b) defined Kernel-based Random Forest (KeRF) estimates and gave explicit expression for the kernels based on Centered RF and Uniform RF. In this paper, we will study the general expression for the connection function(kernel function) of an RF when splits/cuts are performed according to uniform distribution and also according to any general distribution.  We also establish the consistency of KeRF estimates in both cases and their asymptotic normality.


identifier: Yao, Kundi  (2018) Log4Perf: Suggesting and Updating Logging Locations for Web-based Systems' Performance Monitoring.  Masters thesis, Concordia University.

abstract:
Performance assurance activities are an essential step in the release cycle of software systems. Logs have become one of the most important sources of information that is used to monitor, understand and improve software performance. However, developers often face the challenge of making logging decisions, i.e., neither logging too little and logging too much is desirable. Although prior research has proposed techniques to assist in logging decisions, those automated logging guidance techniques are rather general, without considering a particular goal, such as monitoring software performance. In this thesis, we present Log4Perf, an automated approach that provides suggestions of where to insert logging statements with the goal of monitoring web-based systems' software performance. In particular, our approach builds and manipulates a statistical performance model to identify the locations in the source code that statistically significantly influence software performance. To evaluate Log4Perf, we conduct case studies on open source systems, i.e.,
CloudStore and OpenMRS, and one large-scale commercial system. Our evaluation results show that Log4Perf can build well-fit statistical performance models, indicating that such models can be leveraged to investigate the influence of locations in the source code on performance. Also, the suggested logging locations are often small and simple methods that do not have logging statements and that are not performance hotspots, making our approach an ideal complement to traditional approaches that are based on software metrics or performance hotspots. In addition, we proposed approaches that can suggest the need for updating logging locations when software evolves. After evaluating our approach, we manually examine the logging locations that are newly suggested or deprecated and identify seven root-causes.
Log4Perf is integrated into the release engineering process of the commercial software to provide logging suggestions on a regular basis.


identifier: Kumar, Rahul  (2018) Study on Optical Properties and Stability of Gold Nanostars for Localized Surface Plasmon Resonance (LSPR) based Biosensing Applications.  Masters thesis, Concordia University.

abstract:
Exosomes are small vesicles (typically 30-120 nm), formed through the inward budding of endocytic compartments and secreted through fusion of these vesicle-containing endosomes with the plasma membrane. Increasing evidence suggests that exosomes play an important role in cell-to-cell communication through the transport and delivery of cellular components such as lipids, proteins, and nucleic acids. Exosomes preferably accumulate at solid tumor sites due to leaky vasculature and abnormal lymphatic drainage, making them an attractive candidate for detecting cancer.

In recent years, nanoparticles have paved pathway to detect exosomes by incorporating of targeting functionality onto nanoparticle surfaces of the nanoparticles. Among various nanoparticles, Gold nanostars possess interesting tunable properties that can be exploited in different nanomedicine applications including drug delivery systems, thermal-ablation, and image contrast agents.

As nanoparticle properties are directly related to their size and shape, it is a fundamental criterion to ensure high control and precision during the synthesis to obtain anisotropic nanoparticles with desired properties. Gold nanostars were synthesized by seed-mediated method using biocompatible capping agents to control and stabilize nanoparticle morphology during the reactions. First step was to obtain small gold nanoparticles that served as seeds for the growth of branches to finally obtain nanoparticles with the desired star-shape. Gold seeds were obtained by chemical reaction method incorporating citrate as capping agent; monodisperse colloidal nanoparticles (30 ± 5 nm core diameter) were efficiently obtained. Characterization showed that gold seeds possessed a well-defined spherical structure. Silver nitrate was added to the growth solution which acts as a catalyst to activate the site for the formation of branches.

However, in most cases these nanostars possess poor long-term stability, short branch length, polydispersity and suffer from aggregation. In order to address these issues, this thesis focuses characterization of physical properties such as size and morphology using numerical and experimental methods to enhance the synthesis and stabilization of gold nanostars for Localized Surface Plasmon Resonance (LSPR) based biosensing of exosomes. The results show a highly sensitive biosensing platform with prolonged shelf life of more than a year. Biomolecule such as Streptavidin, Biotin, PEGylated (PEG) and Vn peptide (Vn96) were used as surface functionalization molecules on gold nanostars for detecting exosomes. The results show great promise in comparison to standard spherical nanoparticles.


identifier: Neriya Hegade, Keshava Praveena  (2018) Studies on droplet-microcantilever platform under fluid flow in mini wind tunnel.  Masters thesis, Concordia University.

format: text text

abstract:
Fluid interaction of micro structures find numerous applications in bio medical field. This thesis consists of experimental studies on fluid interaction of micro structures under laminar flow using a mini wind tunnel. The interaction of microstructures such as micro cantilever and oil coated water droplet with fluid flow were tested and the experimental results are reported. A mini wind tunnel to test microstructures is designed and built. Design of the mini wind tunnel is validated by performing tip deflection studies of micro cantilever beams of different sizes in millimeter range. The interaction of micro cantilever beam with fluid flow is recorded using a recording camera. An image processing method is developed to extract results from recordings. Results from micro cantilever experiments suggest that tip deflection is highly influenced by beam length and beam thickness.
Deformation of oil coated water droplets are tested under fluid flow. The micro structure is placed over a partially wetting surface and the deformation of the oil-droplet samples are tested using the mini wind tunnel. Effects of fluid velocity, droplet volume and oil concentration over droplet deformation are studied. Larger droplets deform more as compared to their smaller counterparts. Oil layer covers the water droplet entirely and reduces the influence of fluid force. Higher oil coating induces lesser deformation in droplets
Oil coated droplets are subjected to fluid velocities greater than critical air velocity of the droplets to study the droplet shedding phenomena. Oil coated droplet slip easily as compared to the droplet with no oil coatings for a given fluid velocity. Also, oil coating improve the droplet shedding phenomena. However much higher oil coating slows down droplet shedding and the water droplet floats over pool of oil.
Tip deflection of a microcantilever beam with a point load near the free end under the fluid flow is studied to develop fluid load augmented micro balance. Water droplets of various sizes are used to provide point load. The water droplet is placed over micro cantilever beam at dimensionless length ξ =0.8. An additional fluid load is provided using a mini wind tunnel. Tip deflection of the beam is tested for different fluid velocities. Results suggest that fluid load augments the tip deflection of micro cantilever beam. This thesis also develops fluid load augmented micro balance.


identifier: M-BORNAY, BAHMAN ORCID: https://orcid.org/0000-0001-9351-9968 <https://orcid.org/0000-0001-9351-9968>  (2018) OPTIMIZATION OF RAILWAY TRANSPORTATION HAZMATS AND REGULAR COMMODITIES.  Masters thesis, Concordia University.

abstract:
Transportation of dangerous goods has been receiving more attention in the realm of academic and scientific research during the last few decades as countries have been increasingly becoming industrialized throughout the world, thereby making Hazmats an integral part of our life style. However, the number of scholarly articles in this field is not as many as those of other areas in SCM. Considering the low-probability-and-high-consequence (LPHC) essence of transportation of Hazmats, on the one hand, and immense volume of shipments accounting for more than hundred tons in North America and Europe, on the other, we can safely state that the number of scholarly articles and dissertations have not been proportional to the significance of the subject of interest. On this ground, we conducted our research to contribute towards further developing the domain of Hazmats transportation, and sustainable supply chain management (SSCM), in general terms.
Transportation of Hazmats, from logistical standpoint, may include all modes of transport via air, marine, road and rail, as well as intermodal transportation systems. Although road shipment is predominant in most of the literature, railway transportation of Hazmats has proven to be a potentially significant means of transporting dangerous goods with respect to both economies of scale and risk of transportation; these factors, have not just given rise to more thoroughly investigation of intermodal transportation of Hazmats using road and rail networks, but has encouraged the competition between rail and road companies which may indeed have some inherent advantages compared to the other medium due to their infrastructural and technological backgrounds. Truck shipment has ostensibly proven to be providing more flexibility; trains, per contra, provide more reliability in terms of transport risk for conveying Hazmats in bulks.
In this thesis, in consonance with the aforementioned motivation, we provide an introduction into the hazardous commodities shipment through rail network in the first chapter of the thesis. Providing relevant statistics on the volume of Hazmat goods, number of accidents, rate of incidents, and rate of fatalities and injuries due to the incidents involving Hazmats, will shed light onto the significance of the topic under study. As well, we review the most pertinent articles while putting more emphasis on the state-of-the-art papers, in chapter two. Following the discussion in chapter 3 and looking at the problem from carrier company’s perspective, a mixed integer quadratically constraint problem (MIQCP) is developed which seeks for the minimization of transportation cost under a set of constraints including those associating with Hazmats. Due to the complexity of the problem, the risk function has been piecewise linearized using a set of auxiliary variables, thereby resulting in an MIP problem. Further, considering the interests of both carrier companies and regulatory agencies, which are minimization of cost and risk, respectively, a multiobjective MINLP model is developed, which has been reduced to an MILP through piecewise linearization of the risk term in the objective function. For both single-objective and multiobjective formulations, model variants with bifurcated and nonbifurcated flows have been presented. Then, in chapter 4, we carry out experiments considering two main cases where the first case presents smaller instances of the problem and the second case focuses on a larger instance of the problem.
Eventually, in chapter five, we conclude the dissertation with a summary of the overall discussion as well as presenting some comments on avenues of future work.


identifier: Cui, Xin  (2018) A Study of Voltage-Mode and Current-Mode Filters Using Modified Current Feedback Operational Amplifier.  Masters thesis, Concordia University.

abstract:
Abstract
A Study of Voltage-Mode and Current-Mode Filters Using
Modified Current Feedback Operational Amplifier
Xin Cui
There is a prevalent use of current-mode (CM) circuit techniques in analog integrated circuit design, in view of the fact that CM circuits offer certain advantages over voltage-mode (VM) circuits in terms of certain performance parameters such as propagation delay, dynamic range, and bandwidth. The characteristics of a CM circuit make it not so vulnerable to the current demands of IC design trends, such as continuously decreased size and lower DC supply voltages. Therefore, some active devices that could be exploited in both CM and VM circuits have drawn a lot of attention, such as the second generation current conveyor (CCII) and operational transconductance amplifier (OTA). However, a large amount of effort has been made on VM circuits due to their dominant form of signal processing in analog circuit design for the past several decades. The concept of network transposition, introduced by Bhattacharyya and Swamy as early as in 1971, is a powerful technique to convert a VM circuit to a CM one and vice-versa, with little physical circuit alteration and retaining the same performance as its voltage-mode counterpart. It is especially attractive in transforming those circuits that employ active devices which are transposes of themselves, such as OTA or CCII-.
Recently, it has been shown in the literature that a new active element, the modified current feedback operational amplifier (MCFOA), is also its own transpose, and hence can be used to design both VM and CM circuits. It is also known that using the same MCFOA, four equivalent realizations are possible for synthesizing a VM filter function, and further, corresponding four CM filter realizations can be obtained utilizing transposition. However, no detailed study has been conducted with regard to the relative performance of the four equivalent VM structures or the corresponding four CM structures, particularly from the point of view of the non-idealness or the parasitic effects of MCFOA on the performance.
This thesis presents a thorough study on band-pass filter (BPF) and notch filter (NF) implemented with MCFOA both in the voltage-mode and their transposed current-mode counterparts. The transfer functions of the four configurations of voltage-mode circuits, as well as that of the current-mode circuits, should be the same when the MCFOA is ideal. However, in practice, they are influenced by parasitic parameters. Accordingly, the performances of the band-pass and notch filters are influenced remarkably by the parasitic parameters of the active device, namely, MCFOA, especially the parasitic resistances for low frequency applications. These effects are studied by comparing the theoretical and SPICE simulation results of the four configurations of the voltage- and current-mode BPF and NF using non-ideal MCFOA.
In addition, an improved MCFOA that reduces the effect of parasitic resistances is proposed. Performance of BPF and NF are compared among the four configurations of voltage- and current-mode circuits using the improved MCFOA. They are also compared with those using the original version of MCFOA. It is shown that the proposed MCFOA yields several improvements on the performance of both VM and CM BPFs, such as more attenuation at the low frequencies, and drastic reduction in the ω_p and Q_p errors.
Based on the fact that MCFOA is composed of two CCIIs (CCII+ and CCII-), and FTFN can be realized with minor modifications of CCII-, it is natural to compare the performance of BPF using CCII- and FTFN with that using MCFOA. Thus, BPF using CCII- and FTFN and their transposed circuits are also studied. As mentioned earlier, CCII- is its own transpose. However, FTFN does not have a proposed admittance or a hybrid matrix for us to find its transpose. An attempt to find the admittance matrix of FTFN is explored in this thesis. The results show that FTFN can be used as its own transpose only under ideal conditions. Comparisons of performance of BPFs using the original MCFOA, the proposed MCFOA, and CCII-, as well as among their transposes, are presented. It is shown that BPF using the proposed MCFOA exhibits the best performance.