identifier: Pouya, Hamed  (2018) New Models and Algorithms in Telecommunication Networks.  PhD thesis, Concordia University.

abstract:
The telecommunications industry is growing very fast and frequently faces technological developments. Due to the competition between service providers and high expected reliability from their customers, they should be able first, to  migrate their networks to the novel advancements in order to be able to meet their customers’ latest requirements and second, to optimally use the resources in order to maximize their profitability.
Many researchers have studied different scenarios for Network Migration Problem (NMP). In these studies, a comparison between the legacy and new technologies is investigated in terms of time frames, reduction in expenditures, revenue increases, etc. There have been no prior studies considering the operational costs of NMP e.g., technicians, engineers and travels. The first contribution of the thesis is to propose a two-phase algorithm based on the solution of column generation models that builds a migration plan with minimum overall migration time or cost.
The second contribution is an improved decomposition model for NMP by removing the symmetry between the  network connections. We apply a branch-and-price algorithm in order to obtain an epsolin-optimal ILP solution.
The third contribution of the thesis is to propose a new methodology for Wavelength Defragmentation Problem to recover the capacity of WDM networks in dynamic environments and optimize resource usages. Since rerouting the lightpaths in an arbitrary order may result in a huge number of disruptions, an algorithm based on a nested column generation technique is proposed. The solution is an optimized configuration in terms of resource usage (number of links) that is reachable by no disruptions from the current provisioning.
All the algorithms presented in this thesis are based on Column Generation method, a decomposition framework to tackle large-scale optimization problems.


identifier: Nardone, Michael D.  (2018) Of the Repository: Poetics in a Networked Digital Milieu.  PhD thesis, Concordia University.

type: Thesis NonPeerReviewed

abstract:
This doctoral dissertation is a material and cultural analysis of the entwined histories of the three major North American digital repositories of contemporary avant-garde and experimental poetry: the Electronic Poetry Center at the State University of New York at Buffalo, Kenneth Goldsmith’s UbuWeb, and PennSound at the University of Pennsylvania. The dissertation takes up a media-historical methodology to document the actors, publics, discourses, aesthetics, institutional environments, technological infrastructures, and social relations involved in the production of these open online repositories. The research begins from the premise that, in the study of what writing is, has been, and might be, the discourse of poetics and the figure of the archive fuse together. If, as Kate Eichhorn (2003) argues, “[t]o write in a digital age is to write in the archive,” in this research I ask: What can the composition of archives – their materials, contexts, protocols, and interfaces – teach us about poetics today?

Since the mid-1990s, these three repositories have served as a primary means for extending the purview and program of poetics as a contemporary institutional formation. In doing so, the creators of these repositories have utilized them as important media infrastructures for the publication, dissemination, and storage of poetic works and critical analysis on the contemporary production of poetry. Each digital repository is an argument for a specific poetics. Their entwined histories and cultural-technical infrastructures articulate numerous affinities, yet each is distinct in the way it casts a new light on certain critical terms for literary studies. Approaching each in terms of its emphasis on, respectively, access, circulation, and format enables a detailed engagement with the aesthetic, institutional, legal, and technological concerns of the digital repository. Here, this dissertation develops a unique methodology for addressing these complicated structures called digital repositories by emphasizing each case study’s particular bias. Such an engagement opens on to a more general consideration of language, writing, and textuality in networked milieus, and emphasizes the particular affordances that make the digital repository a significant, yet underkacknowledged, archival genre.


identifier: Dugan, Dana  (2019) Art of (dis)obedience: A Study of Critical Embodiment Through a Circus Body.  Masters thesis, Concordia University.

format: video text

abstract:
In a critical examination of circus and its larger socio-political context, the concept and practice of (dis)obedience aims to alter or eradicate authoritarian power relationships between the doing and undoing of oppressive codes and traditional embodiments - normal and queer, success and failure - as a circus body. Its intent functions to expose and interrogate such binary power relationships and transgress authoritarian paradigms such as North American circus and Paul Preciado’s pharmacopornographic capitalism. How can a circus body and its embodied knowledge re-imagine and challenge current existing authoritarian paradigms?
The inquiry into what a circus body is, its embodied knowledge (technical and aesthetic practices), and its relation to and engagement with authority are explored in this thesis. The inquiries originated from my hermeneutic phenomenological circus practice and informed my theoretical investigations. I investigated through my circus body as both researcher and object of study, providing unique insights into the particularities of that common engagement. Through this process, the circus body, its embodied knowledge, and (dis)obedience emerged as the three pivotal concepts of interest in this research. In current circus discourse, these concepts have yet to be fully explored. There are two parts to this thesis—a thesis performance (Dialogues of Disobedience), which in turn informs the second part, the theoretical analysis and synthesis in Art of (dis)obedience: A study of critical embodiment through a circus body. The result is a working theoretical proposition for four of the nine essentials I identify of a circus body – a baseline model for understanding the specificities of my circus body and for establishing the habits developed through technical practice as a form of embodied knowledge. From (dis)obedience, new embodiments and practices manifested in queer and grotesque aesthetics that serve socially conscious practice and performance. Unconventional propositions of new performance forms in both artistic and scholarly mediums emerged from the act of undoing through (dis)obedience towards self-determination and innovation.
This thesis offers discourse from a practice-based perspective that is highly under-represented in current circus research. It also strives to speak to both the scholarly and artistic communities, and to contribute to the burgeoning field of circus scholarship through an intimate account of my approach to artistic scholarly research.


identifier: Nam, Jungbae  (2018) Critical L-values of Primitive Forms Twisted by Dirichlet Characters.  PhD thesis, Concordia University.

abstract:
Let f be a primitive form of weight k > 1 with nebentypus ε and χ be a primitive Dirichlet character. Then, we consider the twist of f by χ and its Dirichlet L-series denoted by L(f, s, χ). Those central L-values (or even vanishings and nonvanishings of them) are believed to encode important arithmetic invariants of algebraic objects over various fields.

In this thesis, we mainly study vanishings and nonvanishings of the central Lvalues of primitive form f of weight k ≥ 2 twisted by χ of a prime order l. More precisely, firstly, assume that k > 2, 2 | k and l > 2. Then, as a generalisation of the nonvanishing theorem for k = 2 of Fearnley, Kisilevsky and Kuwata, for the case that L(f, k/2) 6= 0 we prove that for all but finitely many primes l there exist infinitely
many of twists of order l such that L(f, k/2, χ) 6= 0. We also present numerical results on vanishings of twists of l = 3, 5, and 7 for some primitive forms of k > 2, and based on the random matrix theory, make a conjecture that for a primitive form of even weight k > 2, there exist only a finite number of vanishings of twists of order l > 2.

Secondly, assume that k = 2 and l = 3. Then, inspired by the work of Fiorilli for quadratic twists, we estimate the average analytic rank of twists for the group family under some hypotheses including the generalised Riemann hypothesis, which implies that there exist infinitely many cubic twists such that L(f, 1, χ) 6= 0.

Lastly, consider quadratic twists of an elliptic curve E over Q of conductor N associated with quadratic characters χd of fundamental discriminants d with a prime |d|. Then, by controlling 2-Selmer groups of E and its quadratic twist by χd using the method of Mazur and Rubin, we show that for some E satisfying some conditions there exist a set of residue classes |d| mod N such that L(E, 1, χd) 6= 0 under the Birch and Swinnerton-Dyer conjecture.


identifier: Alzhouri, Fadi  (2018) Dynamic Pricing Strategy for Maximizing Cloud Revenue.  PhD thesis, Concordia University.

abstract:
The unexpected growth, flexibility and dynamism of information technology (IT) over the last
decade has radically altered the civilization lifestyle and this boom continues as yet. Many nations
have been competing to be forefront of this technological revolution, quite embracing the opportunities
created by the advancements in this field in order to boost economy growth and to increase the
accomplishments of everyday’s life. Cloud computing is one of the most promising achievement of
these advancements. However, it faces many challenges and barriers like any new industry. Managing
and maximizing such a very complex system business revenue is of paramount importance.
The wealth of the cloud protfolio comes from the proceeds of three main services: Infrastructure as
a service (IaaS), Software as a service (SaaS), and Platform as a service (PaaS).

The Infrastructure as a Service (IaaS) cloud industry that relies on leasing virtual machines (VMs)
has a significant portion of business values. Therefore many enterprises show frantic effort to capture
the largest portion through the introducing of many different pricing models to satisfy not
merely customers’ demands but essentially providers’ requirements. Indeed, one of the most challenging
requirements is finding the dynamic equilibrium between two conflicting phenomena: underutilization
and surging congestion. Spot instance has been presented as an elegant solution to
overcome these situations aiming to gain more profits. However, previous studies on recent spot
pricing schemes reveal an artificial pricing policy that does not comply with the dynamic nature of
these phenomena.

In this thesis, we investigate dynamic pricing of stagnant resources so as to maximize cloud revenue.
To achieve this task, we reveal the necessities and objectives that underlie the importance of
adopting cloud providers to dynamic price model, analyze adopted dynamic pricing strategy for real
cloud enterprises and create dynamic pricing model which could be a strategic pricing model for
IaaS cloud providers to increase the marginal profit and also to overcome technical barriers simultaneously.

First, we formulate the maximum expected reward under discrete finite-horizon Markovian decisions
and characterize model properties under optimum controlling conditions. The initial approach
manages one class but multiple fares of virtual machines. For this purpose, the proposed approach
leverages Markov decision processes, a number of properties under optimum controlling conditions
that characterize a model’s behaviour, and approximate stochastic dynamic programming using linear
programming to create a practical model.

Second, our seminal work directs us to explore the most sensitive factors that drive price dynamism
and to mitigate the high dimensionality of such a large-scale problem through conducting column
generation. More specifically we employ a decomposition approach.

Third, we observe that most previous work tackled one class of virtual machines merely. Therefore,
we extend our study to cover multiple classes of virtual machines. Intuitively, dynamic price
of multiple classes model is much more efficient from one side but practically is more challenging
from another side. Consequently, our approach of dynamic pricing can scale up or down the price
efficiently and effectively according to stagnant resources and load threshold aims to maximize the
IaaS cloud revenue.


identifier: Seif Afjehei, Sara  (2019) iPerfDetector: Characterizing and Detecting Performance Anti-patterns in iOS Applications.  Masters thesis, Concordia University.

abstract:
Performance issues in mobile applications (i.e., apps) often have a direct impact on the user experience. However, due to limited testing resources and fast-paced software development cycles,
many performance issues remain undiscovered when the apps are released. As found by a prior study, these performance issues are one of the most common complaints that app users have. Unfortunately, there is a limited support to help developers avoid or detect performance issues in mobile apps.
In this thesis, we conduct an empirical study on performance issues in iOS apps written in Swift language. To the best of our knowledge, this is the first study on performance issues of apps on the iOS platform. We manually studied 235 performance issues that are collected from four open source iOS apps. We found that most performance issues in iOS apps are related to inefficient UI design, memory issues, and inefficient thread handling. We also manually uncovered four performance anti-patterns that recurred in the studied issue reports. To help developers avoid these performance anti-patterns in the code, we implemented a static analysis tool called iPerfDetector. We evaluated iPerfDetector on eight open source and three commercial apps. iPerfDetector successfully detected 34 performance anti-pattern instances in the studied apps, where 31 of them are already confirmed and accepted by developers as potential performance issues. Our case study on the performance impact of the anti-patterns shows that fixing the anti-pattern may improve the performance (i.e., response time, GPU, or CPU) of the workload by up to 80%.


identifier: zandmoghaddam, shahin  (2018) Representing local dynamics within water resource systems through a data-driven emulation approach.  Masters thesis, Concordia University.

abstract: Growing population and socio-economic activities along with looming effects of climate change have led to enormous pressures on water resource systems. To diagnose and quantify potential vulnerabilities, effective tools are required to represent the interactions between limited water availability and competing water demands across a range of spatial and temporal scales. Despite significant progresses in integrated modeling of water resource systems, the majority of existing models are still unable to fully describe the contemplating dynamics within and between elements of water resource systems across all relevant scales and/or variables. Here, a data-driven approach is suggested to represent local details of a water resource system through emulating an existing water resource system model, in which these details have been missed. This is through advising a set of interconnected functional mappings, i.e. integrated emulators, parameterized using the simulation results of the existing model at a common scale and/or variable but can support process representation with finer resolution and/or details. The proposed approach is applied to a complex water resource system in Southern Alberta, Canada, to provide a detailed understanding of the system’s dynamics at the Oldman Reservoir, which is the key to provision of effective water resource management in this semi-arid and already stressed cold region. By proposing a rigorous setup/falsification procedure, a set of alternative hypotheses for emulators describing the local dynamics of local irrigation demand and withdrawals along with reservoir release and evaporation is developed. Findings show that emulators formed using Artificial Neural Networks mainly outperform simpler emulators developed for the variables considered. The non-falsified emulators are then coupled to represent the local dynamics of the water resource system at the reservoir location, considering the underlying interplays with hydro-climatological conditions and human decision on the irrigation area. It is found that emulators with input variables identified through expert knowledge can outperform fully data-driven emulators in which proxies were selected based on an input variable selection method.  The top non-falsified coupled models are able to capture the dynamic of lake evaporation, water withdrawal, irrigation demand, reservoir release and storage with coefficient of determination of 0.80 to 0.82, 0.45 to 0.55, 0.52 to 0.59, 0.98 to 0.99 and 0.72 to 0.88, respectively. The practical utility of the proposed approach is demonstrated through an impact assessment study by analysing four performance criteria, corresponding to reservoir’s storage, local irrigation demand, number of spill events and median reservoir release, in three stress-tests. These stress tests asses the local sensitivity of water resource system at the Oldman reservoir at three different levels, corresponding to (1) changing incoming streamflow to the basin in a bottom-up approach; (2) joint scenario of changing streamflow and warming climate, using a coupled bottom-up/top-down approach; and (3) specific changes in incoming streamflow, climate and irrigation area in a heuristic approach. For the first experimentation, weekly realizations for possible water availability are stochastically reconstructed and fed into the top non-falsified integrated emulator. By defining warm/dry, historical and cold/wet flow conditions, we found through alteration from dry to wet regime condition, the expected number of low storage duration is not changed, and expected annual water deficit is declined. Moreover, the expected number of spill events increases whereas median reservoir release increases. In the next impact assessment study, different scenarios of warming climate obtained from NASA-NEX downscaled global climate projections and the joint impact of changing streamflow and temperature on the system’s behaviour is evaluated. This assessment demonstrated that in warmer climate, the expected number of low storage duration in dry condition increases whereas in historical and wet conditions, the low storage duration does not change. In addition, the expected annual water deficit increases while the expected number of spill events decreases in the three flow regime conditions. Moreover, the expected median reservoir release increases in the dry, historical and wet regime conditions. In the final level of assessment, vulnerability of the system under changing streamflow, climate including temperature and precipitation and changing irrigation area is assessed. Results show that increasing irrigation area combined with declining inflow can considerably increase the duration of low reservoir storage in the Oldman Reservoir. Increasing temperature can lead to decline in both reservoir storage and outflow. In addition, when combined with declining inflow, increasing temperature can severely increase the annual water deficit for irrigation sector. Furthermore, it is noted that although the performance of unfalsified models are identical in representing the dynamics of the Oldman Reservoir under the historical data, but assessment can be slightly to moderately different depending on the defined scenarios of change. This is due to the choice of model configuration and can address the uncertainty regarding the system’s behaviour. Our study shows the promise of data-driven emulation approach as a tool for developing more enhanced water resource system models to face emerging management problems in the era of change.


identifier: Sierra, Giancarlo  (2019) Towards the Repayment of Self-Admitted Technical Debt.  Masters thesis, Concordia University.

abstract:
Technical Debt is a metaphor used to express sub-optimal source code implementations that are introduced for short-term benefits that often must be paid back later, at an increased cost. In recent years, various empirical studies have focused on investigating source code comments that indicate Technical Debt, often referred to as Self-Admitted Technical Debt (SATD).

In this thesis, we survey research work on SATD, analyzing characteristics of current approaches and techniques for SATD, dividing literature in three categories: detection, comprehension, and repayment. To set the stage for novel and improved work on SATD, we compile tools, resources, and data sets made publicly available. We also identify areas that are missing investigation, open challenges, and discuss potential future research avenues. From the literature survey, we conclude that most findings and contributions have focused on techniques to identify, classify, and comprehend SATD. Few studies focused on the repayment or management of SATD, which is an essential goal of studying technical debt for software maintenance.

Therefore, we perform an empirical study towards SATD repayment. We conducted a preliminary online survey with developers to understand the elements they consider to prioritize SATD. With the acquired knowledge from the survey responses and previous literature work, we select metrics to estimate SATD repayment effort. We examine SATD instances found in software systems to see how it has been repaid and investigate the possibility of using historical data at the time of SATD introduction as indicators for SATD that should be addressed. We find two SATD repayment effort metrics that can be consistently modeled in our studied projects and surface the best early indicators for important SATD.


identifier: Gorji, Yasaman  (2018) All In The Family: Three Studies on Kinship, Networks and Career Outcomes.  PhD thesis, Concordia University.

abstract:
The first essay studies the impact of kinship by distinguishing between two forms of nepotism on the career outcome of the show business families’ descendants. We show that within more modern industries which are characterized by the boundaryless career environment, direct nepotism is not as efficient as indirect nepotism. We hypothesize that indirect forms of nepotism are evident in the form of network sponsorship by third-party associates of prominent show business families in the Hollywood movie industry. This study predicts that sponsorship will have significant beneficial effects on show business family relatives' career performance and that the effect is accentuated for women in show business families. We find strong support for our sponsorship hypotheses, but we also note the continuing importance of direct forms of family preferment in an industry characterized by single-project organizations and boundaryless careers.
The second essay studies the extended definition of kinship, namely Marriage. It poses the question of whether contemporary intra-professional marriage may be a type of elective affinity (McKinnon, 2010), an institution used reciprocally to further the professional careers of two individuals. The study hypothesizes that marriage benefits spouses by allowing them to capitalize on each other’s accumulated social capital to increase their employability.
Moreover, marriage benefits spouses by allowing them to capitalize on Alter’s accumulated social capital to ascend the industry executive hierarchy by being hired in managerial roles. Also, marriage disproportionately benefits women by enabling female ego to capitalize on male spouse accumulated social capital such that gender bias can be overcome by enabling female ego’s increased involvement in projects and managerial roles. Our study indicates that marriage between Hollywood industry participants and the potential for borrowed spousal capital creates benefits both parties. It demonstrates that the extent to which alter has extensive connections, centrality, and better status, will benefit in terms of more opportunities for employment. Moreover, interestingly, a closed network with more constraint is also beneficial in project-based industries.
The final essay investigates the impact of positive status shift for a member of a show business family and its possible positive or negative reputations spillover effect on the other members of the family. Family members’ impact on individuals’ career choices, career paths, and career development has been a topic for empirical research for a few decades. However, whether a positive status shift would generate spillover benefits to those closely associated with the winners remains understudied.


identifier: Semrouni, Nabil  (2018) Étude des personnages et analyse sociocritique dans Nedjma de Kateb Yacine et Ce que le jour doit à la nuit de Yasmina Khadra.  Masters thesis, Concordia University.

abstract:
This thesis studies two Algerian novels of French expression, Nedjma (1956) by Kateb Yacine
and What the day owes the night (2008) by Yasmina Khadra. Both works are about colonial
Algeria. A story of passion, a love story between a man and a woman, a story of shared love by
several men for the same woman, and finally, a story of love for a country in emergence, on path
to national emancipation: such are the themes. This love for a woman and for a homeland
expresses itself through characters who aim to be often carriers of sociological and political
ideals. The characters in these novels bear a social discourse; they reflect on a changing world
and their visions are often the echo of a torn society. Relationships break down, friendships fade,
a country gains its independence and love is the only hope perhaps still possible.

What interests us more particularly are the possible meanings of the love polygons that
are present in the novels Nedjma and What the day owes the night. The question we might ask
ourselves is: “What do these love polygons mean for the characters, and what do they mean from
a sociocritical perspective”? Our hypothesis is that each of the characters in the novels under
study would be a possible representation of the Algerian people and of its contradictions in the
colonial context.
We will answer our problem by using some key concepts: sociological criticism as
developed by Dominique Maingueneau; an in-depth study of the novel character relying on
Georg Lukacs; and the notion of polyphony as defined by Mikhaïl Bakhtine. It is by studying the
characters and making a sociocritical analysis of our two novels that we will be able to make our
books “talk”, to see what they already say and to interpret them in a rigorous way.


identifier: Kaur, Navjot  (2019) Optoelectronic Humidity and Temperature Sensor using Apodized Pi-Phase Shifted Fiber Bragg Grating.  Masters thesis, Concordia University.

abstract:
Abstract
Optoelectronic Humidity and Temperature Sensor using Apodized Pi-Phase Shifted Fiber Bragg Grating
Navjot Kaur
Humidity control and moisture detection have a wide range of applications in major industries like food storage, chemical plants, electronic instruments, building/construction, medicine, museums and libraries. The most reliable humidity detection methods using capacitors and resistors fail under hazardous operational environments like transformers. Optical gratings based sensors are hence preferred in such conditions due to their properties of light weight, remote sensing and immunity to electro-magnetic interferences.
In this work, an optical humidity sensor based on a rarely investigated FBG is developed. It is called a π-phase shifted fiber Bragg grating (PSFBG). A sharp spectrum signal of PSFBG promises higher resolution in sensing applications. The surface area of the grating developed along an optical cable is coated by a hygroscopic polymer, Polyimide, that undergoes a reversible volume expansion on exposure to humidity. This leads to stress onto the grating and further a shift in the Bragg wavelength.
 In order to investigate the electromagnetic wave propagation inside the core of fiber, a study is conducted in COMSOL multiphysics. The implementation of an optical fiber as humidity sensor is modeled. The mechanism of humidity absorption by the polymer layer is simulated and analyzed. Spectral improvements in the sensor signal in terms of interference are implemented using an optimized apodization function. The spectral signal of sensing element is simulated by transfer matrix solution of coupled mode theory in MATLAB. The results of modeling are used to fabricate a sensor containing two 24-mm PSFBGs separated by 12 mm. A distributed feedback laser scanner is used to precisely characterize and evaluate the device performance. The sensor response to changes in humidity and temperature of the environment is recorded. The experimental results are relatively in good agreement with those obtained theoretically.


identifier: Parent, Laurence  (2018) Rouler/Wheeling Montréal: Moving through, Resisting and Belonging in an Ableist City.  PhD thesis, Concordia University.

abstract: Despite the growing literature on walking practices, mobile methods, differential mobilities and mobility justice, little is known about what it means to move through cities using a wheelchair. While other mobilities researchers engage with wheeling – for example, those studying cycling – I offer a new perspective on a type of wheeling that has been historically ignored and devalued. At a time when cities are taking actions to build more walkable environments, understanding the experiences of disabled people is critical. As a researcher using a motorized wheelchair, I explore what it means to conduct wheeling interviews, instead of “traditional” walking interviews, with 15 disabled Montrealers. The interviews are recorded on a GoPro camera, mounted on my wheelchair and theirs – for interviewees who had one. One participant walks with the assistance of a dog and another uses a white cane. The mobile methodology developed in this research builds on Arseli Dokumaci’s (2013; 2014a; 2014b; 2018) research on disability as a method and the affordances of the everyday as well as on my own activist research on ableism at the Mobile Media Lab at Concordia University. Through the wheeling interviews in different Montréal’s boroughs, I examine participants’ everyday mobilities and two different dimensions of participants’ sense of belonging: their belonging in Montréal disability communities and their belonging in the city. I analyze participant’s experiences mainly through critical disability studies, mobility studies and oral history. Participants’ stories show that their right to the city and their capacity to move through it are severely compromised because ableism is embedded in Montréal’s built environment and culture. Yet few participants question their belonging in the city or proudly declare their attachment to the city. The lack of vocabulary in French for talking about ableism makes it difficult to discuss sense of belonging from a critical perspective. Furthermore, disabled Montrealers are not all equal in the face of the ableist city’s barriers. Those who experience several types of discrimination – for example racism and ableism – are more likely to face obstacles and to question their sense of belonging. I conclude the thesis by proposing 51 actions to build an anti-ableist city.


identifier: Covert, Andrew  (2018) The Zapruder Film as Representational Crisis.  PhD thesis, Concordia University.

abstract:
Abraham Zapruder's 26-second film of the assassination of John F. Kennedy is an indisputably unique piece of cinema. Despite its incredible currency in the world of national political history, and the shadowy world of conspiracy, it has a checkered past with regards to its assimilation into the discourse of film studies. Looked at, variably, as a piece of documentary, reportage or abstract fragment, it has been discussed largely for its cultural, historical or legal impact. This dissertation will chart its deeper implications when considered as a discrete film text and theoretical object, and will contend that, in this light, the Zapruder film participates in a fundamental disruption of the cinematic apparatus’ promise of a holistic representation of reality.

This disruption will be fundamentally connected to the film’s interaction with the primary theoretical concepts of attraction, indexicality and contingency as they are understood in the discipline. An investigation of the Zapruder film’s formal and structural similarities to the earliest cinematic products and the disruptions connected to the cinema of attractions and early types of “event” filmmaking will be essential.

Connections to the use of attractions in experimental film will also show productive comparisons. Fiction film’s connection to these issues and their engagement with the disruption proposed by the Zapruder film will also be important. Here it will be necessary to chart the way narrative can act as both a palliative and intensifying force for the epistemological uncertainty of the images proposed. Finally, we must understand the extent to which the dynamic and ever-changing context of digital remediation has affected the disruptions of the Zapruder film.

All of these considerations are not intended to fix the meaning of the Zapruder film or to detract from its impact in other realms. The key intervention of this dissertation is to open a space for it, not as an orphan child of circumstance, but deeply connected to the process and fundamental structure of cinematic representations as such. This work then is not so much recuperative as it is meant to fully understand and appreciate the depth to which film texts on the borders of the discipline can speak to its very core.


identifier: Christiaans, Junesse  (2018) Designing and Developing Curriculum for a Guadeloupean High school: Exploring Youth Identity with Tumblr.  Masters thesis, Concordia University.

format: text other other

abstract:
This thesis-project equivalent documents an autoethnographic study that leads to the design and development of a curriculum. The autoethnography documents lived experiences in Guadeloupe, a French Antillean island, during the 2016-2017 academic year. Concepts of identity including race and belonging were subjectively explored in the autoethnography and then through activities in the curriculum.
The curriculum was designed to address the specific cultural and academic needs of high school students in Guadeloupe. This English as a foreign language environment emphasized multiple languages as a source of success while battling its own history of cultural genocide. A balance of embracing diversity and maintaining traditional cultures has been an ongoing struggle for foreign teachers working within these diverse populations.
The curriculum presented in this paper addressed the complexities of that setting while fostering a space for young people to discuss their own perceptions of identity and exploring them through Tumblr.  Enforcing digital etiquette practices, online security and privacy policies, and navigating the digital world in English were tangible tools developed through the program. The program emphasized both soft and hard skills specifically designed for a Web 2.0 era where young people are expected to be well versed in technology and critical analysis.


identifier: Lapointe, Julien  (2018) Cinematic Objects, Events and their Predications: An Analytic-Cognitivist Theory of the Viewing Experience.  PhD thesis, Concordia University.

abstract:
This thesis addresses a recurring question throughout the history of discourses about film watching, including in film studies and cognitive film theory (henceforth, cognitivism). Namely: by what theoretical propositions and explanations are we to convey the cognitive, perceptual and affective experience of film going? Cognitivism has made the most decisive inroads, while falling prey to occasional lacunae, as part one (chapters one-two) of this thesis make plain. Cognitivist authors, while ameliorating the claims of previous schools (e.g. canonical contemporary film theory) err in their choice of terms and/or theoretical models. By contrast, ideas inherited from analytic philosophy are invoked to advance an alternate approach, albeit one consistent with cognitivist principles and aims (e.g. schema theory). This thesis’s contribution to knowledge is thus to posit an abstract model of the interpretive actions occasioned by the experience of film texts, such that all potential viewing experiences (of all potential film texts) are covered.
Following analytic philosophy’s ontology of individuation and eventhood, the thesis posits objects and events as the two fundamental categories informing the viewing experience of films. The argument is augmented with subject-predicate logic, whereby objects and events are jointly identified and predicated. Objects are predicated alternately new or old, while events are short or long – predication-types borne out by analytic philosophy, as well as film and art criticism. Part two (chapters three-four) delineate the operations whereby objects are identified and predicated within film texts. Part three (chapters five-six) pursues the same explanatory account for cinematic events. The analysis culminates in part four (chapter seven), in which joint predications of objects and events complete the range of interpretive categories fundamental to the viewing experience.
In concluding, the broader reaches of the preceding work are articulated. Divergences in the philosophy of science point to research projects for cognitivism, with emphasis accorded to either empirical research and corroboration, or conceptual analysis, coherence and parsimony. The latter priority – conceptual analysis – is invoked to urge film scholars to analytic philosophy. The expectation is that further study of this oft overlook tradition will yield novel, unexpected insights into the experience of cinematic artefacts.


identifier: Abdelaal, Mohamed Abdelaziz Mohamed ORCID: https://orcid.org/0000-0002-2034-4981 <https://orcid.org/0000-0002-2034-4981>  (2018) Design and Analysis of Microwave Devices Based on Gap Waveguide Technology.  PhD thesis, Concordia University.

abstract:
Among state-of-the-art guiding structures, the Ridge Gap Waveguide (RGW) is a promising technology, as it minimizes the losses in high-frequency applications and supports wide operating bandwidth. There is another form of the guiding structures that utilize the idea of the Artificial Magnetic Conductor (AMC) surfaces such as Groove Gap Waveguide (GGWG). It has the same advantages as the RGW in terms of losses, and immunity to leakages without the need for electrical contacts, but with different dispersion characteristics. The RGW supports a quasi-TEM mode while the GGWG supports TE modes as it's a different form of the rectangular waveguide. Therefore, GGWG has high power capability comparable to the standard waveguides. As currently, interest is increasing of millimeter wave and microwave applications, the RGW and GGWG are excellent candidates for these applications due to their low loss. It is quite essential to develop microwave components with superior electrical characteristics for such applications.

The anisotropic materials have useful physical properties that can benefit the microwave devices, due to their enormous advantages such as high stability and wide bandwidth in the millimeter wave band. Ferrite is an example of such anisotropic materials. Their properties can be deployed to improve the performance of the millimeter microwave devices in terms of higher stability, wider band, and high power handling.

Taking advantages of the above characteristics, the research work in this thesis is focusing on their use for microwave and millimeter wave frequencies. The presented devices are responsible for the feeding of the antenna systems. Moreover, they can be deployed in different applications such as antenna beamforming. In this thesis, the differential phase shifters and the orthomode transducers (OMTs) are realized by different technologies that are suitable for both of the microwave and the millimeter wave bands that serve different applications of the wireless communication systems.

The research work done can also be summarized in two parts. The first part starts with the study and investigation of the ferrite material properties and their role in the microwave devices. Then, later providing a new accurate model with mathematical formulas for the differential ferrite phase shifter. Moreover, a new design methodology for those phase shifters is presented. Later, the ferrite is applied in the conventional waveguide, Substrate Integrated Waveguide (SIW), and RGW technologies.

In the second part, study, design, and analysis of different types of the orthomode transducers are presented. They are devices responsible for combining and separation of two orthogonal polarizations. The presented OMTs has a compact size with excellent performance. Several OMT types are considered such as the one-fold symmetry, asymmetric, and two-fold symmetry. The first mentioned two OMTs are realized by deploying the waveguide technology, while the two-fold symmetry OMT is based on the GGWG technology. It has the ability to design a feeding network for an array of antennas based on the GGWG technology. Moreover, this OMT is fabricated using 3D printed technology that uses the carbonated plastic material, in which two copper layers are covering all the structure surfaces by electroplating. This fabrication is a new promising technology that is not expensive, lightweight and less complex than traditional machining. However, there are some concerns about power handling and high temperature withstanding. Such problems might have a solution in the future with a more accurate 3D metallic printers.


identifier: Nasseri Bahrabad, Niloufar  (2019) Solving Resource Constrained Project Scheduling Problems (RCPSP) with Remanufacturing.  Masters thesis, Concordia University.

abstract:
Scheduling is one of the crucial issues in the project planning phase. Completing the project in the desired duration with the available resources with minimum cost is a big challenge for project managers.
In the recent decades, several approaches have been proposed to deal with the resource constraints in scheduling. It can create a serious bottleneck and drastically change the flow of the activities. Moreover, resource constrains can change the project duration in crashing the project even if the activity (which creates the bottleneck) is not on the critical path.
To address this issue, a new approach for Resource Constrained Project Scheduling (RCPS) is proposed when the remanufacturing option for some activities is available in order to crash the project. In this research, first a mathematical model for RCPS is presented. Then, a new algorithm is proposed to shorten the project duration by activating remanufacturing line (if possible) or paying the crash cost. The proposed algorithm is implemented in MATLAB and some computational experiments have been done to demonstrate the effectiveness and sensitivity of the proposed procedures. The algorithm is also validated on a practical case study which is a manufacturing industry in the northern Ontario.


identifier: Mirzaei, Amir  (2018) Development of a Hierarchical Zinc Oxide Photocatalyst for the Removal of Emerging Contaminants from Water.  PhD thesis, Concordia University.

abstract: The presence of emerging contaminants (ECs) such as antibiotics in water bodies has raised increasing concern since they are continuously introduced in aquatic ecosystem and may cause unpredictable environmental hazards and risks, even at trace concentrations. Conventional water treatment processes are known to be generally inadequate for the elimination of these persistent contaminants. As an alternative to conventional biological water treatment processes, photocatalytic degradation of antibiotics has been identified as a promising technique, as it may lead to the mineralization of contaminants into carbon dioxide, water and mineral acid. However, high energy consumption, fast recombination of photo-generated charges, low stability and difficulty in the separation of photocatalysts from treated solution are the main limitations of this process. Herein, to address these obstacles, a low energy consuming photoreactor was designed and built. Besides, the efficiency of process was improved by fluorination and exfoliation of synthesized hierarchical photocatalysts with magnetic properties based on ZnO and graphitic carbon nitride (g-C3N4) as a wide and narrow band gap photocatalyst, respectively. The synthesized photocatalysts were characterized by several characterization tests. The effect of operating parameters such as catalyst dosage, solution pH and airflow rate on the antibiotics removal efficiency and the optimization of process was studied by response surface methodology (RSM). Under the optimum conditions, the photocatalytic removal performance was examined in terms of sulfamethoxazole (SMX), ampicillin (AMP) and amoxicillin (AMX) removal and mineralization as well as detoxification of the solution and by-product formation. Moreover, the reaction kinetics, energy consumption, stability and reusability of photocatalysts were evaluated. Based on the LC-HR-MS/MS method, the formation of several by-products during the degradation of antibiotics was evaluated and a degradation pathway for SMX and AMX was proposed. The results showed that in comparison with a 500 W visible lamp, using a UV lamp (10 W) was considerably more effective for AMX removal, its mineralization and detoxification of the solution. Compared to reported values in the literature, the removal efficiency, mineralization, detoxification and energy consumption for the removal of examined antibiotics were improved in this study.


identifier: Behzadi, Mojeanne Sarah  (2017) Iridescent Spirituality: Early Experiments in Expanded Cinema.  Masters thesis, Concordia University.

abstract:
This thesis sets out to examine three works of expanded cinema from the 1950s that preceded the psychedelic light shows of the 1960s with which they are often associated with. Through the medium of light, German avant-garde artist Oskar Fischinger’s Lumigraph (1951), San Francisco Beat filmmaker Jordan Belson’s Vortex concerts (1957-1959) and Beat writer and artist Brion Gysin’s Dream Machine (1958) expressed a quest for inner truths and cosmic connections.

Each work emerged in a distinct context and this study reveals the meaningful intersections of the artists’ trajectories. Created during the postwar years characterized by uncertainty, cynicism and rapid technological development; the discussed art works reveal a shared belief in light’s potential as a vehicle through which to experience forms of spirituality that were outside mainstream forms of devotion in the Western world.


identifier: Aghdaie, Mohammad Hasan ORCID: https://orcid.org/0000-0001-6877-5724 <https://orcid.org/0000-0001-6877-5724>  (2019) Robust Water Resource Planning at River Basins.  Masters thesis, Concordia University.

abstract:
Freshwater is a fundamental, but scarce resource vital for life. Uncertainty is one of
the significant factors in water resource systems planning and management problems.
We consider the problem of water resource systems planning at river basins when
there are competing demands and different operating policies. Firstly, we provide
a mathematical model using the minimum cost network
flow problem, in which the
system is represented as a directed multi-graph. Arc coefficients are introduced for
modeling gain/loss in the system. Multiple arcs are used to create of the system
priorities. Secondly, we reformulate the aforementioned problem using cardinality-constrained
robust optimization to address uncertainty when there is an agreement
amongst decision makers about uncertainty sets. A set of experiments is conducted
to demonstrate the trade-off between the level of robustness and the cost of robustness.
We also use Monte-Carlo simulation to analyze the performance of the model in
terms of its feasibility in the presence of uncertainty. Thirdly, we employ robust decision
making (RDM) to address uncertainty when there is not an agreement amongst
decision makers. RDM is applied to analyze the system performance under evaporation/
precipitation uncertainty. Monte-Carlo simulation is used to take samples from
the uncertain future ranges. To evaluate the policies multiple attribute decision making
(MADM) methodology is used. We have shown that the combination of RDM
and MADM is a suitable approach for dealing with deep uncertainty and selecting the
most suitable robust strategy. This thesis provides insight into modeling uncertainty
in river basins systems.


identifier: Hooda, Sohail  (2019) Argument Labeling of Discourse Relations using LSTM Neural Networks.  Masters thesis, Concordia University.

abstract: A discourse relation can be described as a linguistic unit that is composed of sub-units that, when combined, present more information than the sum of its parts. A discourse relation is usually comprised of two arguments that relate to each other in a given form. A discourse relation may have another optional sub-unit called the discourse connective that connects the two arguments and describes the relationship between the two more explicitly. This is called Explicit Discourse relation. Extracting or labeling arguments present in an explicit discourse relations is a challenging task. In recent years, due to the CoNLL competitions, feature engineering has been applied to allow various machine learning models to achieve an F-measure value of about 55%. However, feature engineering is brittle and hand-crafted, requiring advanced knowledge of linguistics as well as the dataset in question. In this thesis, we propose an approach for segmenting (or identifying the boundaries of) Arg1 and Arg2 without feature engineering. We introduce a Bidirectional Long Short-Term Memory (LSTM) based model for argument labeling. We experimented with multiple configurations of our model. Using the Penn Discourse Treebank (PDTB) dataset, our best model achieved an F1 measure of 23.05% without any feature engineering. This is significantly higher than the 20.52% achieved by the state of the art Recurrent Neural Network (RNN) approach, but significantly lower than the feature based state of the art systems. On the other hand, because our approach learns only from the raw dataset, it is more widely applicable to multiple textual genres and languages.


identifier: Ankam, Divya  (2019) Distributions based Regression Techniques for Compositional Data.  Masters thesis, Concordia University.

abstract: A systematic study of regression methods for compositional data, which are unique and rare are explored in this thesis. We start with the basic machine learning concept of regression. We use regression equations to solve a classification problem. With partial least squares discriminant analysis (PLS-DA), we follow regression algorithms and solve classification problems, like spam filtering and intrusion detection. After getting the basic understanding of how regression works, we move on to more complex algorithms of distributions based regression. We explore the uni-dimensional case of distributions, applied to regression, the beta-regression. This gives us an understanding of how, when the data to be predicted, or the outcome, is assumed to be of beta distribution, a prediction can be made with regression equations. To further enhance our understanding, we look into Dirichlet distribution, which is for a multi-dimensional case. Unlike traditional regression, here we are predicting a compositional outcome. Two novel regression approaches based on distributions are proposed for compositional data, namely generalized Dirichlet regression and Beta-Liouville regression. They are extensions of Beta regression in a multi-dimensional scenario, similar to Dirichlet regression. The models are learned by maximum likelihood estimation algorithm using Newton-Raphson approach. The performance comparison between the proposed models and other popular solutions is given and both synthetic and real data sets extracted from challenging applications such as market share analysis using Google-Trends and occupancy estimation in smart buildings are evaluated to show the merits of the proposed approaches. Our work will act as a tool for product based companies to estimate how their investments in advertising have yielded results in the market shares. Google-Trends gives an estimate of the popularity of a company, which reflects the effect of advertisements. This thesis bridges the gap between open source data from Google-Trends and market shares.


identifier: Xu, Danyang  (2019) Time-Domain System Identification for Long-EZ Fixed-Wing Aircraft Based on Flight Test Data.  Masters thesis, Concordia University.

abstract:
System identification using flight test data based on time-domain method is an accurate way of getting a reliable mathematical aircraft model. This thesis provides a system identification procedure on a canard configured fixed-wing aircraft Long-EZ, which is the early and critical stage of providing accurate aircraft models for designing an effective autopilot in the future.
Flight test designed for Long-EZ aircraft has been carried out by International Test Pilot School (ITPS Canada Ltd). The real flight test data recorded from the testbed has been utilized for the identification and verification of a linear transfer function model, a nonlinear neural network model, and a block-oriented model consisting of linear and nonlinear parts. The linear transfer function structure has been determined with aircraft’s physical dynamics, and the model parameters have been identified using MATLAB System Identification toolbox. The nonlinearity of the aircraft dynamics has been treated with a Multilayer Perceptron (MLP) neural network structure, which has been developed with a set of Python codes. Flight data has been utilized to train this MLP structure.
The results demonstrate different predicting capabilities of the developed linear, nonlinear, and combined linear and nonlinear structure, which is also known as the neural network Wiener model. The developed Wiener model in general shows satisfactory predicting capability for the testbed Long-EZ aircraft.


identifier: Jiang, Ning  (2019) The Relationship between Political Connections and Firm Performance: A Study of China’s Special Treatment Stocks.  Masters thesis, Concordia University.

abstract: In this paper, we examine whether political connections can influence the performance of publicly traded Chinese firms. Specifically, we focus on so-called special status (ST) warnings that are imposed on firms after two consecutive years of losses, as well as the likelihood of being accused of fraud by the China Securities Regulatory Commission (CSRC). Our results show that political connections can help reduce a firm’s risk of receiving an ST warning and can even increase its probability of reverting back to normal trading status. In addition, we find that politically linked enterprises are more likely to be accused of fraud. Our results highlight the importance of political connections in business activities and shed light on the potential dark side of this form of external support. While firms can greatly benefit from their relationship with the government, it does not necessarily mean that connected companies enjoy healthy operations or promising future development. These firms may more easily survive in troubles and recover after periods of negative earnings, but they also exhibit a greater likelihood of financial misconduct and/or related government investigations.


identifier: Li, Jing  (2019) Experimental study of open-channel flow and turbulence over roughness elements.  Masters thesis, Concordia University.

abstract: It is common that open-channel flows are turbulent and the channel-bed surfaces are rough. The presence of roughness elements on the channel-bed has significant influences on the flow characteristics in the bed vicinity and further above. Some earlier researchers have created two-dimensional roughness in laboratory channels by placing rectangular ribs on the bed and three-dimensional roughness by gluing sediment grains of irregular shape on the bed. Elements in the form of cubes are arguably more suitable to quantify the influences. However, laboratory experiments for detailed measurements of flow velocity and turbulence over cubical elements are rarely available. In this thesis, laboratory experiments of turbulent flow over acrylic cubes in a rectangular channel were carried out. Cubes with sides of 1.905 cm (3/4 inches) are uniformly mounted as roughness elements on the horizontal bed. The approach flow depth ranges from 8.8 to 9.1 cm or 4.62 to 4.78 times the roughness height. The experiments cover three conditions of cube spacing: being 2, 4, and 6 times the cube side dimensions; these relative spacing conditions represent the d-type, intermedium-type, and k-type roughness, respectively. Using an acoustic Doppler velocimeter (ADV), detailed measurements of three-dimensional flow velocities and turbulence quantities were made at locations above and around the cubes. At each location, the measurements lasted 60 s, at a sampling frequency of 120 Hz. The positions of the ADV probe were controlled accurately ( 1 mm) by a step motor. The velocity distributions are shown to be much more complex than the boundary-layer velocity distributions widely used in the literature. We categorized vertical profiles of the longitudinal velocity component into six distinct types (types 1 – 6) and vertical profiles of turbulent shear stress into five types (types 1 – 5). Based on measurements of the longitudinal velocity component and turbulent shear stress, we calculated velocity distributions for the d-type roughness by using the logarithmic law. There are large discrepancies between the calculation results and measurements. Moreover, we obtained contours of the secondary flow intensity in various planes. The distributions of the secondary flow are symmetrical with respect to the channel centreline at some cross sections but asymmetrical at other cross sections. The k-type roughness is shown to produce stronger secondary flow than the d-type and intermediate type of roughness. The experimental results are useful for model validations.


identifier: Saeed, Saroosh  (2019) Fault Protection Scheme for DC Nanogrids Based on the Coordination of Fault-Insensitive Power Electronic Interfaces and Contactors.  Masters thesis, Concordia University.

abstract:
DC power distribution systems (especially DC nanogrids) are becoming a great area of interest for researchers, that can lead to a better integration of DERs and supplying local loads in a more efficient way compared to AC systems. DC nanogrids for Net-Zero Energy Homes (NZEHs) are expected to include a number of Distributed Energy Resources (DERs) in relatively close proximity. The control structure can be based on a hierarchical approach with DC bus signaling (DBS). Power electronics interfaces (uni-directional Boost for sources and bi-directional Class-C for storage units) are usually employed as the interface of DERs in DC nano and microgrids. However, these power interfaces are fault-sensitive, meaning that in case of a fault in the DC bus, with a DC bus voltage lower than the source voltage, the upper anti-parallel diode conducts. Thus, one loses control of the current injected into the DC nanogrid. In conventional systems, this current is typically high enough to open the DC Circuit Breakers (CBs). One issue in DC nanogrids is the difficulty in making only the DC CBs close to the fault to open. Various control schemes have been developed for power balance and energy management, but fault protection still remains an issue.
This Thesis discusses the realization of a fault detection and isolation scheme which is based on the coordination of fault-insensitive power electronics interfaces and low cost contactors. A bi-directional 4-switch DC-DC converter is employed in this work which allows the control of the injected current regardless the source voltage to be lower or higher than the DC bus voltage. Fault current limiting and blocking capabilities of the fault-insensitive converter allows the use of low cost and lower rated contactors. The identification of which segment(s) of the DC nanogrid is(are) faulted and which contactor(s) should open is based on peer-to-peer communication between DERs. Following the detection of a fault, the DERs decrease the injected current to a value low enough for safe action of the contactors.
Finally, the proposed concepts are verified with hardware experiments. Experimental results with power electronics interfaces operating with DC Bus Signaling (DBS) with VI curves including droop, current limiting and a CAN communication system are presented. It is shown that the DC grid can be protected against faults by coordinating the action of power interfaces and contactors, and only the faulted segment is isolated keeping the healthy part of the DC nanogrid energized.


identifier: Haghighatmamaghani, Alireza  (2019) Hydrothermal/Solvothermal Synthesis of Hierarchical Titanium Dioxide Photocatalysts for Indoor Air Purification.  PhD thesis, Concordia University.

abstract:
Energy saving policies applied to modern buildings, tighter building envelopes, and decline in outdoor air quality promote the escalation in levels of indoor air pollutants. In recent years, concerns regarding the impact of indoor air quality (IAQ) on human health especially in well-insulated buildings in metropolitans have created a pressing need for reliable air remediation technologies. Heterogeneous ultraviolet photocatalytic oxidation (UV-PCO) has been put forward as an efficient method to ameliorate IAQ via catalytic degradation of harmful organic compounds to benign final products.
In this context, developing highly photoactive and durable photocatalysts that can perform satisfactorily under realistic conditions is sought after to expedite UV-PCO systems commercialization. Photocatalyst’s performance is a function of several interconnected features: crystallinity, crystal phase and size, surface area, porosity, surface chemistry, light-harvesting ability, exposed facet, and charge-separation efficiency. In this regard, thanks to their unique morphology and multimodal porosity, hierarchical photocatalysts can incorporate high molecular diffusion/transport, superior light harvesting, and large surface area. Template-free hydrothermal/solvothermal route is a green, versatile, and less costly strategy for fabricating hierarchical photocatalysts with controlled characteristics.
Taking into account the above-mentioned merits of hierarchical photocatalysts and hydrothermal synthesis method, the core objectives of this research are:
1)	Synthesize hierarchically porous titanium dioxide materials with enhanced photoactivity with respect to commercially available photocatalysts (e.g. P25) via hydrothermal method.
2)	Explore the complex preparation-property-performance relationships for titanium dioxide photocatalysts utilized in photocatalytic air purification.
3)	Examine the role of photocatalyst’s morphology in photocatalytic degradation by developing several potentially promising structures and assess their performance.
4)	Investigate the improvement in photocatalytic filter activity and stability with combining hierarchical titanium dioxide with carbonaceous support.
5)	Evaluate the activity of photocatalysts under realistic operating conditions to provide reliable information regarding the capability of UV-PCO air purifiers.
To accomplish these goals, a large number of TiO2 photocatalysts are synthesized by systematically varying the hydrothermal preparation parameters (e.g. time, temperature, pressure, pH, solvent, titanium precursor, calcination temperature, etc.). Accordingly, by means of comprehensive characterization, the influence of synthetic methodology on textural, morphological, and crystallographic properties of photocatalysts is investigated. In the last stage, the performance of photocatalyst is evaluated by degradation of two prevalent indoor air pollutants (toluene and methyl ethyl ketone (MEK)) at wide ranges of operating conditions.


identifier: Ali Adib, Maya  (2019) The Fortune inside the Garden: Eradicating Accelerated Negative Environmental Impact through Profits.  Masters thesis, Concordia University.

abstract:
With the world shifting toward more sustainable economic growth, a global demand for innovative
solutions to incorporate sustainability in the decision-making has emerged. This work challenges
the premise that financial profits and pro-environmental purposes are mutually exclusive. The
research addresses a major barrier that the corporate sector faces in incorporating sustainability
in the decision-making: Corporate Short-Termism (CST) (UNGC, 2017). CST stems from the fact
that there is a significant segment of investors with excessive sensitivity to companies’ short-term
financial performance, these investors tend to pressure management away from sustainability
related investments as sustainability investments tend to not generate positive short-term returns. The
work tackles the question on how the corporate sector could increase its sustainability
investments to generate a positive impact on the environment without compromising its ability to
cater to its short-term investors’ needs.
While previous work recommended addressing CST through regulations change, direct incentives
to short-term investors and even a system-wide financial reform, this work proposes a different
perspective, a perspective that responds directly to what management perceive as the main
cause for CST: The industry-wide competition. Our proposed framework utilizes the same main
element that enforces CST: competition and recommends overcoming CST through profits. This
would be achieved by targeting a fast-growing consumer market segment; labeled the conflicted
consumers. Tapping on this growing market segment would generate short-term financial returns
while investing in sustainability. The conflicted consumer market segment differs from the general public by having favorable environmental/ethical beliefs and by their willingness to defect to
sellers who offer them viable options on environmental/ethical products. In 2007, the conflicted
consumer segment was estimated to be 25% of all consumers and that this segment is growing
fast (Watts, 2007 & Winston 2007).
This work utilizes the Theory of Planned Behavior (TPB) and New Institutional Economics (NIE)
to gauge the conflicted consumer’s intention to purchase environmental products and to
understand the root of this purchasing behavior. A paper-pencil survey (n=136) was conducted
to gauge the conflicted consumer intention to purchase organic food. Organic food was chosen
because organic agriculture has a notable positive environmental impact (FAO). In addition,
organic food is perceived favorably by the conflicted consumers.
Our findings reveal that only the elements of the Perceived Behavior Control (PBC) play a
significant role in explaining the intention to purchase organic food by the conflicted consumer.
Furthermore, the research utilizes NIE framework for economic change to demonstrate the
mechanism in which a positive impact on the environment could take place. Our analysis reveals
that consumers’ pro-environmental beliefs would translate into a purchasing decision if these
beliefs are in line with the main uncertainty priority of the consumer, or if the elements of the
environmental products are not in conflict with the main uncertainty priority of the consumer. In
other words, improving the elements of PBC in the environmental products offerings leads to
demand creation by the conflicted consumers, which in turn lead to short-term financial returns
and overcoming of the CST barrier while investing in sustainability.


identifier: Kodukothanahally Nagaraju, Shivaprakash  (2018) Community Assembly and Habitat Specialization of Tropical Tree Species along Moisture Gradients in the Western Ghats Biodiversity Hotspot in India.  PhD thesis, Concordia University.

abstract: The interactions between ecological and evolutionary processes mediated through functional traits that confer habitat specialization have been proposed to explain the spatial assembly of plant communities both across space and in different habitats. However, the scale at which these mechanisms operate and their relative importance in dominance and assembly of tree communities in different habitat types distributed across spatially-varying environmental gradients in tropical forests have been rarely tested. Here, I elucidate patterns of functional trait and phylogenetic variation and evolutionary history of key functional traits conferring habitat specialization to understand community assembly mechanisms operating within in tropical tree communities distributed across spatially varying environmental gradients and in different habitat types in Western Ghats biodiversity hotspot, India. The chapter 2 focuses on patterns of functional trait and phylogenetic co-variation among a community of tropical canopy trees distributed across spatially varying moisture gradient. I find that tree communities in plots that experience lower precipitation and longer duration of dry period show clustering of both functional traits and phylogenetic relationship suggesting environmental filtering play a key role in the assembly of tree communities in these forests. The chapter 3 explores the relationship between key functional traits, phylogenetic relationship and abundance of 210 co-occurring tree species distributed across contrasting extremes of seasonal flooding gradient i.e. flooded forest and terra-firme forest (non-flooded). I found that repeated evolution of key functional traits together with strong environmental filtering play a key role in determining the ecological success (dominance) and assembly of tree communities in flooded habitat. The chapter 4 focuses on climatic niche evolution and evolutionary history of flooded habitat specialization in global and endemic Myristicaceae members in the Western Ghats. I found that, repeated gain of swamp habitat specialization and associated morphological traits in global and Western Ghats Myristicaceae implying seasonal flooding gradient is an important driver of ecological speciation. I also found that local habitat specialization promotes range-wide niche evolution among sister taxa. By elucidating the pattern functional traits and phylogenetic relationship across flooding and spatially varying moisture gradient and analysis of climatic niche evolution and habitat specialization among co-occurring sister taxa, this thesis contributes to our understanding of the determinants of assembly, dominance and diversification of tropical tree communities across diverse habitat types in tropical forest biomes.


identifier: Makdessian, Lucy  (2019) Exploring experiences of young-adult Quebec gay men in the workplace after the sex-education reform by Quebec’s Ministry of Education.  Masters thesis, Concordia University.

abstract:
Using the photovoice method, this thesis study explored the lives of four young gay men in Quebec as they navigate their work, family and social life having received sex education after the 1997 and 2001 sex education reforms put forth by the Ministry of Education of Quebec.  These reforms removed sex education from the formal curriculum and expected sex education to be incorporated across the curriculum and be taught from a cross-disciplinary approach. The main three themes of the photovoice findings are: (1) Hiding or suppressing sexual orientation in general and in the workplace. (2) A reluctance to express sexual orientation with family. (3) The need to address stereotypes associated with gay men.  Another interesting finding was that change is expected to come from within the gay community or individuals rather than externally.  Furthermore, the results indicated that overall the experience of these four young men during high school lacked pertinent LGB education leading to reluctance to express sexual orientation.
The following recommendations are advanced: (1) Provide sex-education and sexual diversity in well developed curriculum units rather than the present across the curriculum approach dependent on teachers’ comfort level.  (2) Position the LGB as part of the norm – teaching with a vision of LGBH rather than LGB as diversity from the norm of Heterosexuality.  (3) Include gender identity and gender diversity as part of sexual diversity inclusive education, extending the educational approach to LGBTQH.  (4) Provide workplace sensitivity training that includes sexual diversity.  (5) Revise the teacher education curriculum to equip teachers with the necessary knowledge and skills to develop age appropriate curriculum units to teach about LGBTQH.


identifier: Labelle, Frédérique  (2018) Investigation of the Lower Limb Neuromuscular Activation in Children Following a Perturbation.  Masters thesis, Concordia University.

abstract: Females and males are at risk for ACL injuries and are shown to benefit from injury-prevention programs. An ACL injury sustained during childhood or adolescence is associated with an increase in morbidity, including early development of osteoarthritis, long term disability, and chronic pain. That the incidence of ACL injuries in children is higher in females when compared with males suggests that the pre-pubertal and pubertal period of growth and motor development may be a significant factor in injury risks related to the ACL. Unfortunately, very few studies have looked at situations that might contribute to injury and prevention of lower extremity injury in children. To determine potential injury risk, it is important to examine the activity and recruitment order of lower limb muscles to target deficiencies that can be addressed with IPPs. Female and male children participants were recruited from sports teams and organizations in Montreal, QC. Data was collected using the Noraxon DTS EMG, and a goniometer. Participants were asked to maintain balance on their non-dominant leg during unexpected perturbations in the lateral, posterior, and rotational motions as well as a combination motion that mimics an ACL injury mechanism. Our results show that differences exist between males and females 8-12 years old. For both sexes, muscle activation patterns previously identified as predisposing factors to ACL injuries were found, which suggests that injury prevention programs are of value to implement and study in this age group.


identifier: Nguyen, Tien Dat  (2019) Diversification Benefits of European Small- Cap Stocks After the Global Financial Crisis and Brexit.  Masters thesis, Concordia University.

abstract: In this paper we investigate the diversification gains obtained from investing in European small-cap stocks, focusing on the periods since the Global Financial Crisis and Brexit. We find mixed evidence to support the assertion that European small-caps provide diversification benefits to a benchmark portfolio of large US stocks. The benefits are further reduced when benchmark assets include both a US large-cap portfolio as well as a portfolio of European large-cap stocks. After Brexit, US investors achieve diversification benefits from investments in European large-cap stocks. However, after Brexit, small-cap stocks from only one country in the EU are shown to provide further diversification gains.


identifier: Sjollema, Sandra  (2018) What Is Found There? Poetry and Emotions in Resistance and Power for Social Change Among Diverse Community Poets.  PhD thesis, Concordia University.

abstract:
For many who identify with marginalized social positions, participating in community art has signaled a means of resisting oppressive systems of power. In these settings, art acts as a means of challenging hegemonic ideas, building solidarity and establishing collective power. At the same time, academics have come to embrace the arts as an invigorating and alternative form of research. The arts–and, especially, poetry–have come to be viewed as a means of understanding people’s personal and emotional knowing. In addition, the arts, as well as emotions, have come to be considered as essential components to a deeper understanding of social change.

The purpose of this study was to ask about the significance of community poetry and emotions as vehicles for individual and collective resistance and power in social change efforts among diverse community poets in Montréal. Data collection included five poems written by community poets as well as interviews with the poets and community organizers. Three major themes were identified in this study: 1) Individual Acts of Poetic Resistance; 2) Community Poetry in Interaction: Individual and Collective Power; and 3) Poetry and Emotions: Social Change in Community and Beyond.

The results of the study pointed to the centrality of emotions in social life and suggested how emotions are effective in the social change endeavour. The study revealed that emotions in social change are largely uncertain and complex, especially in milieus that consist of diverse people. The study also indicated that community poetry and emotions are apt means of accessible discursive spaces and alternative practices for people living in marginalized situations, and, as such, exemplified their role in participatory democracy. Additionally, this study suggested that aesthetic features, such as literary devices, intertwined with emotion, play an essential role in art as social change.

This study underscored the need for community organizations and activists to implement activities that emphasize art and emotion, and to validate the contribution these elements can offer to community building and social change. The study’s findings also emphasized the need for scholars to research the role of the community arts in interaction with emotion and social change.


identifier: Madi, Taous  (2018) Security Auditing and Multi-Tenancy Threat Evaluation in Public Cloud Infrastructures.  PhD thesis, Concordia University.

abstract:
Cloud service providers typically adopt the multi-tenancy model to optimize resources usage and achieve the promised cost-effectiveness. However, multi-tenancy in the cloud is a double-edged sword. While it enables cost-effective resource sharing, it increases security risks for the hosted applications. Indeed, multiplexing virtual resources belonging to different tenants on the same physical substrate may lead to critical security concerns such as cross-tenant data leakage and denial of service. Therefore, there is an increased necessity and a pressing need to foster transparency and accountability in multi-tenant clouds. In this regard, auditing security compliance of the cloud provider’s infrastructure against standards, regulations and customers’ policies on one side, and evaluating the multi-tenancy threat on the other side, take on an increasing importance to boost the trust between the cloud stakeholders. However, auditing virtual infrastructures is challenging due to the dynamic and layered nature of the cloud. Particularly, inconsistencies in network isolation mechanisms across
the cloud stack layers (e.g., the infrastructure management layer and the implementation layer), may lead to virtual network isolation breaches that might be undetectable at a single layer. Additionally, evaluating multi-tenancy threats in the cloud requires systematic
ways and effective metrics, which are largely missing in the literature. This thesis work addresses the aforementioned challenges and limitations and articulates around two main topics, namely, security compliance auditing and multi-tenancy threat evaluation in the cloud.
Our objective in the first topic is to propose an automated framework that allows auditing the cloud infrastructure from the structural point of view, while focusing on virtualization-related security properties and consistency between multiple control layers. To this end, we devise a multi-layered model related to each cloud stack layer’s view in order to capture the semantics of the audited data and its relation to consistent isolation requirements. Furthermore, we integrate our auditing system into OpenStack, and present our experimental results on assessing several properties related to virtual network isolation and consistency.
Our results show that our approach can be successfully used to detect virtual network isolation breaches for large OpenStack-based data centers in a reasonable time. The objective of the second topic is to derive security metrics for evaluating the multi-tenancy threats in public clouds. To this end, we propose security metrics to quantify the proximity between tenants’ virtual resources inside the cloud. Those metrics are defined based on the configuration and deployment of a cloud, such that a cloud provider may apply them to evaluate and mitigate co-residency threats. To demonstrate the effectiveness of our metrics and show their usefulness, we conduct case studies based on both real and synthetic cloud data. We further perform extensive simulations using CloudSim and wellknown VM placement policies. The results show that our metrics effectively capture the impact of potential attacks, and the abnormal degrees of co-residency between a victim and potential attackers, which paves the way for the design of effective mitigation solutions against co-residency attacks.


identifier: Sun, Xiaguang  (2018) The effect of brand spokesperson on consumers’ brand gender perceptions.  Masters thesis, Concordia University.

abstract: This research aims to explore the influence of brand spokesperson gender on consumers’ brand gender perceptions. Past research examined and found that spokesperson could contribute to consumers’ brand gender perceptions of an originally gender-neutral brand. Extending past research, and using a between-subject design, this research presents both brand design elements and spokesperson at the same time, and explores how gender congruity/incongruity between brand design and spokesperson influences consumers’ perceptions. The results indicate that consumers do not process advertisements from a gender congruity/incongruity perspective, and discusses possible causes. This research finds that compared to female consumers, male consumers perceive a higher level of both brand femininity and brand masculinity. We also find that brand femininity has a stronger association with spokesperson compared to brand design elements; on the contrary, brand masculinity has a stronger association with brand design elements, in comparison with spokesperson. Moreover, we find that distinct brand gender increases consumers’ brand recall, and that brand attitude has a stronger association with brand masculinity, rather than brand femininity. The results of this research provide both theoretical and managerial implications, and limitations and future research directions are also discussed.


identifier: Arlia Ciommo, Anthony  (2018) Mechanisms of Longevity Extension by Caloric Restriction and Lithocholic Acid in the Yeast Saccharomyces Cerevisiae.  PhD thesis, Concordia University.

abstract:
The objective of studies described in this thesis was to elucidate molecular and cellular mechanisms by which caloric restriction (CR) and lithocholic acid (LCA) extend longevity of the budding yeast Saccharomyces cerevisiae. Recent studies of how CR influences a pattern of metabolism and organelle dynamics in the chronologically aging yeast S. cerevisiae have revealed that this low-calorie diet alters age-related dynamics of ethanol metabolism, lipid synthesis and degradation, trehalose metabolism, ROS homeostasis maintenance, mitochondrial morphology control, mitochondrial functionality preservation, stress response control, cell cycle regulation, quiescence maintenance, and apoptotic and liponecrotic death subroutines. Our hypothesis was that CR may delay yeast chronological aging by altering the age-related dynamics of some or all these cellular processes. Findings presented here support this hypothesis. Indeed, we found that CR slows yeast chronological aging by mechanisms that coordinate the spatiotemporal dynamics of various cellular processes before entry into a non-proliferative state and after such entry. CR causes a stepwise establishment of an aging-delaying cellular pattern by tuning a network that assimilates the following: 1) pathways of carbohydrate and lipid metabolism; 2) communications between the endoplasmic reticulum, lipid droplets, peroxisomes, mitochondria and the cytosol; and 3) a balance between the processes of mitochondrial fusion and fission. Through different phases of the aging process, the CR-dependent remodeling of this intricate network 1) postpones

the age-related onsets of apoptotic and liponecrotic modes of regulated cell death; and 2) actively increases the chance of cell survival by supporting the maintenance of cellular proteostasis. Because CR decreases the risk of cell death and actively increases the chance of cell survival throughout chronological lifespan, this dietary intervention extends longevity of chronologically aging yeast.
We also used a mass spectrometry-based quantitative analysis of the water-soluble cellular metabolome for the investigation of how CR and the longevity-extending tor1Δ mutation (which eliminates the Tor1 protein kinase known to orchestrate the nutrient- and energy-sensing TOR [target of rapamycin] pro-aging signaling pathway) influence the concentrations of various water- soluble metabolites at consecutive stages of the chronological aging process in S. cerevisiae. Our investigation provided the first evidence that both the longevity-extending diet CR and the- longevity extending mutation tor1Δ establish a similar pattern of relative concentrations of methionine metabolism intermediates through the entire process of chronological aging in S. cerevisiae. We proposed a hypothesis that the observed redirection of metabolite flow from the biosynthesis of methionine and spermidine to the biosynthesis of cysteine and glutathione may represent an anti-aging pattern characteristic of the ʺmetabolic signatureʺ of longevity extension in chronologically aging yeast cells placed on the CR diet or having the TOR pro-aging signaling pathway being inactivated.
Based on recent findings from the Titorenko laboratory, we hypothesized that the LCA- driven changes in mitochondrial lipidome may have a causal role in the age-related remodeling of proteome, thus eliciting changes in mitochondrial functionality and delaying yeast chronological aging. To test this hypothesis, we used a mass spectrometry-based quantitative analysis to investigate how certain mutations that eliminate enzymes involved in mitochondrial phospholipid metabolism influence the mitochondrial proteome and how they affect the geroprotective efficiency of LCA in chronologically aging yeast. Our investigation provided the first evidence that LCA-driven specific changes in the composition of mitochondrial membrane lipids cause a distinct remodeling of mitochondrial proteome by decreasing and increasing concentration of many mitochondrial proteins. These proteins have been implicated in such vital mitochondrial functions as the ETC and respiration, the TCA cycle, ribosome assembly, amino acid metabolism, carbohydrate metabolism, protein import, proteostasis, metabolite synthesis, protein synthesis, ATP synthesis, metabolite transport, lipid metabolism, contact sites and cristae maintenance, redox homeostasis, mtDNA maintenance, stress response, mRNA synthesis and processing, the maintenance of contact sites between mitochondria and vacuoles, and mitochondrial fusion. We provided evidence that the LCA-dependent remodeling of mitochondrial lipidome and the resulting changes in mitochondrial proteome are essential for the ability of LCA to delay aging.
Our recent studies have indicated that under CR conditions LCA influences not only the composition and functionality of mitochondria but also some cellular processes confined to other cellular compartments. We therefore hypothesized that LCA may delay chronological aging of yeast limited in calorie supply also because it affects these other cellular processes taking place in various cellular locations. To test this hypothesis, we investigated mechanisms through which LCA controls the spatiotemporal dynamics of these other cellular processes in different cellular locations under CR conditions. Our investigation provided important new insights into the mechanisms by which LCA delays yeast chronological aging under CR conditions by altering the spatiotemporal dynamics of a cellular network that integrates certain pathways of lipid and carbohydrate metabolism, some intercompartmental communications, specific aspects of mitochondrial morphology and functionality, and liponecrotic and apoptotic modes of regulated cell death.
Because LCA triggers major changes in the age-related chronology of several vital processes taking place in mitochondria, we hypothesized that LCA may cause these changes by eliciting a reversible phosphorylation of some mitochondrial proteins. To test this hypothesis, we investigated if an exposure of chronologically aging yeast to exogenous LCA can trigger such phosphorylation. We found that LCA elicits the establishment of a distinct phosphoprotein profile of mitochondria, which significantly differs from the phosphoprotein profile of mitochondria in yeast cells cultured without LCA.


identifier: Detolle, Anais  (2018) « Vive le Québec cidre ! » : le paysage social cidricole québécois. Une ethnographie alcoologique.  PhD thesis, Concordia University.

abstract:
Les cidres du Québec sont des produits sont « localisés » tant par l’origine de leur matière première et leur lieu de fabrication que par le discours des cidriculteurs, des journalistes et des institutions. Leur localisation s’effectue de plus en interaction avec un environnement politique et économique particulier. Cette thèse analyse l’histoire du cidre au Québec en regard des constituantes du paysage social cidricole du Québec. Elle se développe autour des questions suivantes : en quoi le cidre est-il spécifiquement québécois ? Qu’est-ce qui en fait un produit « de qualité » ? Quelles sont les origines de la reconnaissance mondiale dont bénéficie le cidre québécois ? Je réponds à ces questions et plus largement à la question : qu’est-ce qui fait du cidre du Québec ce qu’il est aujourd’hui ?
La thèse est construite en trois parties. La première présente une analyse des changements alimentaires au Québec et de la place des cidriculteurs dans le système alimentaire mondial. J’explique que la forme actuelle de la cidriculture est née en réaction à la mondialisation des marchés et à la dérèglementation de la qualité. La deuxième partie présente une sociogenèse du cidre au sein de l’histoire alimentaire du Québec. Par l’intermédiaire d’une biographie culturelle du cidre et, en particulier, du cidre de glace, elle montre que le cidre n’a pas toujours été un alcool de distinction comme il peut l’être aujourd’hui, mais qu’il a aussi été un objet médical, populaire, interdit, puis détesté et enfin apprécié. La troisième partie est une analyse approfondie des caractéristiques qui font la spécificité du cidre québécois actuel : (1) son héritage agricole ; (2) ses particularités de fabrication (les savoirs) ; (3) l’acquisition des savoir-faire des cidriculteurs ; (4) les savoir-être qui ont permis aux cidriculteurs de faire reconnaitre leur production et de protéger sa qualité.
Grâce à l’utilisation d’une méthode de recherche qualitative et multisectorielle, cette étude du cas du cidre du Québec contribue à l’avancement des connaissances sur les spécificités historiques et politiques du cidre de la province, un exercice qui n’avait jamais été tenté. Enfin, elle illustre la réappropriation de la notion de « qualité » par les producteurs et son utilisation pour changer le paysage alimentaire plus généralement.


identifier: Vajihi, Zara ORCID: https://orcid.org/0000-0003-4200-1178 <https://orcid.org/0000-0003-4200-1178>  (2018) Quantitative ultrasound: low variance estimation of backscattering and attenuation coefficients.  Masters thesis, Concordia University.

abstract:
One of the main limitations of ultrasound imaging is that image quality and interpretation depend on the skill of the user and the experience of the clinician. Quantitative ultrasound (QUS) methods provide objective, system-independent estimates of tissue properties such as acoustic attenuation and backscattering properties of tissue, which are valuable as objective tools for both diagnosis and intervention. Accurate and precise estimation of these properties requires correct compensation for intervening tissue attenuation. Prior attempts to estimate intervening-tissues attenuation based on minimizing cost functions that compared backscattered echo data to models have resulted in limited precision and accuracy. The first contribution of this thesis is that we incorporate the prior information of piece-wise continuity of QUS parameters as an L2 norm regularization term into our cost function to overcome these limitations. We further propose to calculate this cost function using Dynamic Programming (DP), a computationally efficient optimization algorithm that finds the global optimum. Our results on tissue-mimicking phantoms show that DP substantially outperforms a state-of-the-art method in terms of both estimation bias and variance.

The second contribution of this thesis is that to further improve the accuracy and precision of this DP method, we propose to use L1 norm instead of L2 norm as the regularization term in our cost function and optimize the function using DP. Our results show that DP with L1 regularization reduces bias of attenuation and backscatter parameters even further compared to DP with L2 norm. Besides, we employ DP to estimate the QUS parameters of a new phantom with large scatterer size and compare the results of LSq, L2 norm DP and L1 norm DP. Our results show that L1 norm DP outperforms L2 norm DP, which itself outperforms LSq. In the future, the contributions of this thesis can potentially be used for finding imaging biomarkers associated with different types of pathology and help clinicians obtain an objective assessment of intrinsic tissue properties.


identifier: Zaid, Zaid  (2019) Hybrid Energy Storage System for DC Nano-grids.  Masters thesis, Concordia University.

abstract:
Solar photovoltaic (PV) panels and wind turbines are two commonly employed Renewable Energy Sources (RESs). Their main drawback is that they are stochastic and fluctuating sources. Roof-top PV is easier to install and operate in the urban environment. Due to the variable nature of RESs, an energy storage system (ESS) is used to solve the problem of mismatches between the variable power generation and load demand in standalone/islanded systems. The ESS is employed to store surplus energy and supply it back to the system when needed. The most common ESS applied in standalone PV systems is based on batteries. Batteries, in general, have high energy density but low power density, giving low charge/discharge rates. Based on the characteristics of the batteries, it will not be able to respond optimally to fast changing and high frequency power exchanges. One solution to this limitation is by combining batteries and supercapacitors (SCs), which can provide high power but have low energy storage capacity, to form a hybrid ESS (HESS). A battery-SC combination has been considered in this Thesis. The aim of this combination is to reduce the current stresses on the battery occurring due to sudden changes in PV generating and load demand. For that, an effective control method is essential for the optimal operation of the HESS with varying load demand and PV generation.
This Thesis discusses a control strategy for a HESS consisting of three proportional plus integral (PI) type controllers that control the currents of two bidirectional power electronic converters, one for the battery and the other for the SC, connecting them to a common DC bus, whose voltage should be regulated. The boost mode has been considered for modeling the class C interface power converters and designing the relevant PI controllers. For the sake of determining the reference currents for both converters, a low pass filter is used to split the HESS current, required to regulate the common DC bus voltage, into low dynamic components for the battery and fast dynamic components for the SC. First, the analysis of the ESS with a single element (battery) is used with the PV system and variable load to test the performance of the basic inner current and outer DC nano-grid voltage regulation loop. Later, the battery and SC units are used along with the PV system to verify whether the current split technique, with fast dynamic to the SC, can provide fast regulation of the DC bus voltage while reducing the current stress on the battery. A SC voltage control loop has also been designed to keep the SC voltage with a certain reference value. DC nano-grids can also be connected to an AC utility grid. This is usually done by means of a single-phase DC-AC converter that tends to produce a low order voltage harmonic in the DC bus. The usual solution based on a large electrolytic capacitor, presents the drawback that this component presents a short lifetime. The solution employed in this work was to use the HESS to perform an active filtering function, what was accomplished by adding a resonant (R) term to the PI of the DC bus voltage loop. The effectiveness of the control scheme is shown by simulation studies in MATLAB®/Simulink. Finally, experimental results are provided to verify those described by theoretical analysis as well as simulation results.