identifier: Singh, Jashanjot  (2020) Universal Gesture Tracking Framework in OpenISS and ROS and its Applications.  Masters thesis, Concordia University.

abstract:
In this research work, we present a common and extensible framework that abstracts different vision-based gesture recognition middleware and provides uniform gesture recognition data obtained from those via its simpler API to enable hand gesture interaction in different kinds of applications. We demonstrate various aspects of our framework via instrumentation and enable gesture interaction for our two specific yet different needs.
Firstly, we alleviate limited gesture tracking functionality in ISSv2 aka. (Illimitable Space System v2), an interactive and configurable artists' toolbox that is used to create music visualizations, visual effects and interactive documentary film based on the inputs from users such as gestures, voice, motion, etc.
Secondly, we provide a proof-of-concept solution to enhance and demonstrate limited language usability of the FORENSIC LUCID language's composition and compiler interactivity by enabling a forensic investigator to create partial FORENSIC LUCID encoded programs which require manipulation of preloaded digital evidence objects in a 3D warehouse-like application (DigiEVISS) via hand gesture interaction.
We also leverage Robot Operating System (ROS), an open source set of tools and libraries for its communication middleware to broadcast our framework data over the network. We provide this framework as a specialization of the OpenISS core framework and evaluate our framework on various aspects. We employ metrics such as effective frame rate and delay to evaluate our exemplified scenarios that represent our needs.


identifier: Burnside, Kimberly  (2019) Do you know what I know? Investigating the depth of infants’ concept of belief.  PhD thesis, Concordia University.

type: Thesis NonPeerReviewed

abstract:
The main objective of the present dissertation was to investigate the depth of infants’ understanding of beliefs. Specifically, it was crucial to address the “rich” vs. “lean” debate of theory of mind understanding in infancy. The aim of Study 1 was to directly examine whether infants’ looking time pattern commonly observed in the VOE task was replicated when a mechanical toy crane replaced the human agent. Results revealed that infants in the incongruent group did look longer at test than the infants in the congruent group, thus suggesting that infants overattribute false beliefs to inanimate agents.
	The goal of Study 2 was to examine whether infants’ looking time pattern in the VOE task was replicated using a switch agent paradigm. Specifically, infants watched as a true or false belief was attributed to an agent and then watched as a second, naïve agent search for the object at test. As in Study 1, infants in the incongruent group looked longer at test than the infants in the congruent group, indicating that infants formed expectations for this naïve agent’s actions, once again suggesting that infants overattribute beliefs.
	Taken together, the findings from the two studies demonstrate that infants broadly overattribute beliefs to any agents, even those to whom adults would not attribute beliefs. These findings challenge the “rich” view of theory of mind understanding in infancy given that this view posits that infants have a sophisticated understanding of mental states.


identifier: Iovita, Cristina  (2019) Classica bodies, musical throats and an accommodating religion. Recovering the acting codes of the Romantic drama.  PhD thesis, Concordia University.

abstract:
Classical Bodies, Musical Throats and an Accommodating Religion explores the origins of the modern drama from a director’s perspective, with special focus on the “language of cry and gesture”, the acting language of the early Romantic repertory. The purpose of the study is to reconstruct the acting codes of the melodrama, the first dramatic genre to appear on the Romantic stage, based on the workshops and subsequent productions of Witchcraft by Joanna Baillie (co-director
Louis Patrick Leroux) and Leonce and Lena by Georg Büchner which I directed for the Concordia University’s D.B. Clarke Theatre in 2010-2011 and, respectively, for Le Théâtre de
l’Utopie in Montreal in 2013 (Büchner’s Bicentenary) in view of further applications to the modern repertory.


identifier: Allaw, Elissa  (2019) Communicative Language Assessment in L2 Writing.  PhD thesis, Concordia University.

abstract: Despite communicative language teaching’s popularity in many countries, including Canada and America, empirical studies that shed light on practical communicative language teaching and assessment (CLA) of L2 writing are scarce. Therefore, this study opted to contribute to teaching and assessing L2 writing literature from the Communicative Language Teaching (CLT) perspective. First, a Writing Communicative Competence (WCC) rubric was developed drawing on Bachman and Palmer’s (1996, 2010) language testing model, and then, it was pilot tested following a concurrent triangulation mixed-methods design. Six teachers and six learners from a language school in Montreal rated two written samples using the rubric (quantitative component) and responded to an open-ended questionnaire that elicited their opinions about the rubric and their experiences using it. Following the recommendations of teachers and students, the WCC rubric was revised. Second, an intervention study was carried out to explore the effect of communicative competence strategy training using the WCC rubric on L2 writing performance. Twenty intermediate-level participants were divided into two groups: the control group (n = 10) and the experimental group (n = 10). The control group received regular instruction for eight weeks. In addition to regular instruction, the experimental group participated in four explicit strategy training sessions that targeted raising participant’s awareness about writing communicative competence: 1) the teacher explained the components of the WCC rubric and how to use it; 2) the teacher modeled how to apply the rubric to writing and how to assess essays using the rubric; 3) the learners, in pairs, analyzed written samples using the rubric; 4) the learners wrote their essays, assessed their peers’ essays, and revised their essays using the rubric. Twenty-eight raters rated essays that were collected on the pre-test and the post-test and responded to a questionnaire. The results indicated that the WCC rubric is a reliable and useful teaching and assessment tool for L2 writing.


identifier: Mikhail, Amanda  (2019) Fluid Dynamic Structures in the Right Ventricle with Presence of Pulmonary Regurgitation after Tetralogy of Fallot Repair.  Masters thesis, Concordia University.

abstract: Tetralogy of Fallot (TOF), which causes 8-10% of all congenital defects, is a concern for 1 in 2518 parents. Although the effects of this disease can be remedied by a surgery at birth, regurgitation from the pulmonary valve seems to occur two to three decades after this repair in 50% of the operated cases. Since little is known regarding the cause of this regurgitation or simply the natural flows in the right ventricle (RV), this research, which is the first of its kind, aims to shed light on fluid flow in the right ventricle during normal function as well as the effects on the fluid flow due to the introduction of regurgitation from the pulmonary valve. An in-house cardiovascular simulator was used to simulate the pumping action of the right ventricle through the use of a linear motor, which gave rise to the E-wave, while a servo motor gave rise to the A-wave. Various severities of regurgitation, defined by ratio of the effective regurgitant orifice area over the total valve orifice area (ROA/A), (0 ROA/A, 0.012 ROA/A, 0.063 ROA/A and 0.174 ROA/A) were simulated through the restriction of the valve closure while the fluid used was a 60%-40% water-glycerol mixture in order to mimic human blood viscosity. Planar time-resolved particle image velocimetry measurements have been performed on a custom-made double activation simulator reproducing flow conditions in a model of a right ventricle. Changes in flow characteristics in the right ventricle have been evaluated in terms of velocity fields and profiles, tricuspid inflow jet orientation and viscous energy dissipation. Our results show that pulmonary valve regurgitation significantly alters the flow in the right ventricle mostly by impairing the diastolic inflow through the tricuspid valve and by increasing viscous energy loss. This fundamental work should allow for a better understanding of such changes in the RV flow dynamics. It may also help in developing new strategies allowing for a better follow-up of patients with repaired TOF and for decision-making in terms of pulmonary valve replacement.


identifier: Nikonam Mofrad, Raheleh ORCID: https://orcid.org/0000-0003-1779-5834 <https://orcid.org/0000-0003-1779-5834>  (2019) Relationships Between Mechanism of Formation, Microstructure and Properties of Porous Reaction Bonded Silicon Nitride Ceramics.  PhD thesis, Concordia University.

abstract:
Silicon nitride (Si3N4) is one of the most promising candidates for application in gas turbine and piston engines, catalyst supports, diesel particulate filters and interpenetrating composites mainly because it possesses good thermal and chemical stability, high hardness, and excellent corrosion and wear resistance under harsh conditions. Porous Si3N4 ceramics with high porosity have previously been developed by a combination of reaction bonding of Si powder, sacrificial templates and gel-casting. To modify the microstructural and mechanical properties, this technique maybe followed by a post heat-treatment in which samples that contain various oxide aids are heated at elevated temperatures and embedded in a Si3N4-based powder bed. Despite many studies on the fabrication and characterization of porous Si3N4, there is still a lack of understanding of a) the role of additives on the nitriding mechanism and formation of a specific Si3N4 grain morphology, b) the relationship between microstructure and properties of porous ceramics and c) the influence of the powder bed composition on the microstructure of heat-treated Si3N4 ceramics.
The main objective of this study was to investigate the microstructure of porous reaction bonded Si3N4 and its properties in the presence of MgO, CaO and Al2O3. Samples with high porosity were prepared by a process that utilizes a sacrificial template technique, along with gel-casting and nitriding. Mechanisms and thermodynamics of reactions, microstructure of phases present, morphologies of grains and pores, pore size distribution, pore interconnectivity and accessibility, porosity and density, linear shrinkage and weight loss, as well as mechanical strength of the fabricated foams are discussed. For this purpose, microstructural transformations of foams both during in situ nitridation at T≤ 1425℃ and post heat-treatment at T≤ 1700℃ have been considered. Throughout the text, ‘RBSN’ refers to reaction bonded Si3N4 samples with no additive, while in the presence of the above-mentioned oxides, samples have been labelled as MgO-RBSN, CaO-RBSN and Al2O3-RBSN, respectively.
The results revealed that in an atmosphere of ultra-pure nitrogen and during the in situ nitridation of Si, whiskers grew in globular agglomerates into the large pores and decreased the pore interconnectivity and size. However, upon adding MgO, the grain morphology was altered and eventually at 12 wt.% MgO, whisker formation was completely eliminated, and the microstructure was modified to a combination of Si3N4 α-matte grains and β-rods. Based on the results of XRD analyses along with thermodynamic studies, some intermediate phases formed as a result of reactions between volatile MgO and silica, which is naturally present on the surface of Si particles. This possibly decreased the content of SiO (g), as the predominant reactant of α-whisker formation, and altered the ratio of α/β-Si3N4 phases. Subsequently, in this microstructure, the formation of fully interconnected pore channels with large pores (< 40 μm) and clean cavities was confirmed by 3D and 2D visualization images.
Subsequently, the microstructural transition of Si3N4 grains heat-treated in the presence and absence of MgO in the Si3N4-based powder bed (i.e., labelled as SN-MgO and SN powder beds, respectively) was investigated. This illustrated that the grain morphology and microstructures of samples were strongly affected by the presence of volatile MgO in the powder bed. During liquid phase sintering at 1700℃, α-matte dissolved, grains precipitated as coarse β-rods and a Mg-Si-O-N glassy phase was developed. Similarly, α-whiskers gradually disappeared and recrystallized as 100% fine β-grains. During heat-treatment, weight losses and α/β phase ratio were substantially decreased while linear shrinkage and grain coarsening were increased. Unlike α-matte grains, α-whiskers extensively densified upon heat-treatment. This led to a high densification and a sharp decrease in porosity level. Consequently, a macro/microstructure with less interconnectivity, clean spherical cavities and large pore size resulted. The observed microstructural changes occurred due to the high volatility of magnesia, by vapor phase transport of species from the MgO-SN powder bed to the porous structure, and through a subsequent solution-precipitation mechanism. No significant morphology change, shrinkage, densification or phase transformation were observed in the samples heat-treated in SN powder bed.
Subsequently, morphology and microstructures of samples were correlated to the structure of pores, pore size distribution, level of porosity and density. Pores were classified based on their shape (spherical or irregular), size, interconnectivity (open or isolated) and their fabrication mechanism. Pores with large and whisker-free spherical cavities and unimodal pore size distributions were developed in samples composed of either α-matte grains or β-rods. In contrast, complex, fine and irregular pores were fabricated in the presence of elongated Si3N4 whiskers; therefore, a bimodal pore size distribution resulted. This study showed that the obtained foams had tailorable properties allowing mean pore sizes ((d)) ̅ ranging from 1.3 to 13.8 μm and 30 to 76 vol.% porosity.
In addition, the interaction of CaO, MgO and Al2O3 with silicon and nitrogen were examined comparatively. In the presence of CaO and through a reaction between Si (g) and molecular nitrogen, the dominant microstructure was α-matte grains (α/β-Si3N4 ratio≈ 3.9) with interconnected, spherical and open cavities. Formation of intermediate phases due to the reactions with surface silica could have possibly affected the content of SiO vapor and thus hindered the formation of whiskers. By substituting CaO (15 mol%≈  6 wt.%) with the same mol.% of MgO (15 mol%≈ 4.3 wt.%), the content of intermediate phases in the microstructure was reduced, a low number of α-whiskers formed, and the α/β-Si3N4 ratio was decreased by almost 55%. Yet, the highest quantity of whiskers and the lowest α/β-Si3N4 ratio were developed in the presence of Al2O3 (15 mol%≈ 11 wt.%). High thermal and chemical stability of Al2O3 possibly decreased the content of oxygen generated and hindered the formation of intermediate phases. This in turn could increase the likelihood of SiO (g), a reactant required for α-whiskers formation, and atomic nitrogen, a reactant needed for β-phase formation, being present in the atmosphere.
Both compressive strength and flexural strength were increased in the presence of interlocked whiskers with fine inter-particle pores or in structures with low porosity levels, whereas a combination of high porosity and large pores limited the strength of the resultant foams. In addition to the microstructure of pores, interconnectivity and accessibility of pore channels, the amount of shrinkage and densification, weight loss and density were strongly dependent on the presence of different oxide additives. Hence by designing the composition of the starting powder mixture and the surrounding powder bed, tailored microstructures with different mechanical strengths can be easily obtained. This research should be of interest to scientists and engineers concerned with the processing and use of porous ceramics and, in particular, this information and findings can be used in the microstructural design of Si3N4 and related materials.


identifier: Darriet, Camille  (2019) “Awww, That’s Such a Cute Lemon!” The Effect of Whimsical Cuteness on Willingness-to-Pay for Imperfect Produce.  Masters thesis, Concordia University.

abstract: Many consumers prefer to buy “perfect” produce (e.g., a shiny apple) while avoiding imperfect ones that may be dull in colour and/or odd in shape. In my thesis, I wanted to paint a portrait of this type of consumer. To do so, I looked at various demographic, psychographic and behavioural variables, and found that consumers avoid buying imperfect produce and have negative taste, health and effort perceptions. Further, this type of consumer does not connect the purchase of imperfect produce to food waste and/or environmental issues. Given the impact of food waste on environmental and societal well-being, I then examined a way to encourage consumers to purchase imperfect produce (and at more reasonable prices): more specifically, I tested whether “whimsical cuteness” might influence how much consumers are willing-to-pay for imperfect produce based on prior research showing that whimsicality results in greater usage, and consumption, of whimsical objects (Nenkov and Scott, 2014). I also tested whether this type of priming works through curiosity (Wang and Huang, 2018). Across two experiments, I found that when consumers were shown an advertisement for an oddly shaped lemon with (versus without) a characteristic related to whimsical cuteness (i.e., googly eyes), they were later willing-to-pay more for oddly shaped lemons. This effect remained even when I increased the time between purchase and consumption. The mediating role of curiosity, however, was unclear and should be re-considered in future research.


identifier: Melzer, Zachi  (2019) Screen Clusters: Urban Renewal, Architectural Preservation, and the Infrastructures of Urban Media.  PhD thesis, Concordia University.

abstract: As screen technologies proliferate in everyday and quotidian urban contexts, studies of screens placed on façades of buildings have largely focused on understanding how these media can contribute to the formations of responsive, immersive, interactive, and open publics. With these considerations, this thesis historicizes so-called urban screens, public screens, media façades and media architectures as products that are shaped, on the one hand, by the politics of urban renewal and gentrification, and on the other hand, by discourses of architectural and urban preservation. Each chapter focuses on the history of a key site prominently characterized by the presence of screen technologies: Piccadilly Circus in London between 1960-1980 (Chapter 2), Times Square in New York City between 1980-1995 (Chapter 3), Yonge-Dundas Square in Toronto between 1998-2018 (Chapter 4), and Quartier des Spectacles in Montréal between 2000-2018 (Chapter 5). Examining the histories of each site’s development, the thesis comparatively highlights the ways LED screens and digital projections become part of the material infrastructures and legal frameworks of each respective city. Under considerations are the conditions that bring about and the regulations that maintain the infrastructures of urban screen technologies and cultures. Particular focus is given to the ways the placement, size, brightness, cleanliness, spectatorial spaces, maintenance, and contents of urban screens have been both variably as well as similarly articulated. Certain commonalities in the governing and discourses surrounding the four sites — such as, the formation of public-private partnerships, the privatization of public spaces, and the roles that architectural and urban preservation play in contributing to the symbolic capital associated with each site — indicate the presence of key fundamental conditions that shape the geographies, economies, regulations, and cultures of urban screens. Instead of a proliferation of screens in public spaces, it is demonstrated that a rather systemic and uneven organization of screen technologies into select economically and culturally promising clusters in cities exists.


identifier: Arnab, Salman Moazzem  (2019) Modeling and Performance Evaluation of Avalanche Detector Structures for Low Dose Medical X-ray Imaging.  PhD thesis, Concordia University.

abstract:
The flat-panel x-ray detectors based on large area integrated circuit called active matrix array ensure excellent image quality and provide wide dynamic range. As a result, active matrix flat panel imagers (AMFPIs) are now commercially available for chest radiography and mammography. However, at low level exposures, most of the AMFPIs are not quantum noise limited due to the electronic noise of the readout circuitry. Therefore, AMFPIs are not fully commercialized for x-ray fluoroscopy (used for interventional procedures and deployment of endovascular devices) which requires maintaining a very low x-ray exposure. An active research is underway to make AMFPIs quantum noise limited at fluoroscopic exposure level. This work investigates the feasibility of avalanche gain as a solution.

At high electric field, avalanche multiplication of charge carrier improves the signal strength to overcome the effects of electronic noise in both direct and indirect conversion x-ray detectors. Indirect conversion detectors are suitable for the avalanche multiplication. It is because the gain fluctuation is minimum since the x-ray absorption and electric charge collection occur in two separate layers. However, in indirect conversion detectors, the image resolution in terms of modulation transfer function (MTF) deteriorates due to depth dependent x-ray absorption (Lubberts effect) and omni-directional propagation of light photons in the phosphor. In this research work, a cascaded linear-system model is proposed to calculate the image quality of CsI-based indirect conversion a-Se avalanche x-ray detectors in terms of spatial frequency dependent detective quantum efficiency (DQE). The depth dependent MTF and noise power spectrum (NPS) are modeled by incorporating the Lubberts effect. The theoretical model also considers MTF due to K-fluorescence reabsorption. The model is then compared with experimentally determined DQE(f) and shows a better fit than previously published models.
On the other hand, direct conversion directors show a better performance in terms of image resolution as the x-ray photons are directly converted into electron and hole pairs. However, the direct conversion detectors are still vulnerable to the electronic noise at low exposures. Utilization of mesh electrode in order to separate the x-ray absorption and gain region has been proposed in the literature to reduce the avalanche gain fluctuation in direct conversion detectors. This work includes a cascaded linear-system model to calculate the DQE(f) of an a-Se based direct conversion avalanche x-ray detector. The proposed model evaluates charge collection efficiency using the Ramo-Shockley theorem and the actual weighting potential of an individual pixel. A 2-Dimensional simulation is performed to calculate the actual weighting potential in the presence of a mesh electrode. The optimal design parameters and operational condition for a-Se based direct conversion multilayer avalanche x-ray detectors are described in this work.

In order to ease the fabrication process and eliminate the need of applying two different voltages to the aforementioned mesh electrode based direct conversion avalanche detector, a novel structure for direct conversion avalanche detector is proposed. The proposed structure contains a hole trapping layer instead of a mesh electrode to separate the absorption layer from the gain region. A numerical model is developed using Semiconductor Module of COMSOL Multiphysics to analyze the device performance. The electric field profile as a function of various device parameters is calculated. A detailed analysis on the transient behavior of the dark current in presence of blocking and trapping layers is performed. A modified cascaded linear-system model that considers the effect of reabsorption of K-fluorescent x-rays, carrier trapping in different layers and avalanche multiplication of charge carrier is used to calculate the DQE(f) and the MTF of the proposed structure. The DQE(f) of the proposed structure is then compared with published experimental results of a commercially available detector at low x-ray exposures (e.g., exposures used in tomosynthesis).

The relative performance of these detector structures influences their clinical effectiveness. Therefore, a comparison of the performance of these detectors for different x-ray imaging modalities is also presented in this research work.


identifier: Lucas Torres, Omar de Jesus  (2020) Decision making for urban mobility: a macro, meso and micro analysis.  Masters thesis, Concordia University.

abstract:
Urban congestion is a challenge that cities commonly suffer across the globe. Traffic congestion and longer commutes are linked with poor cardiovascular and metabolic health, along with decreased energy and increased stress among the users. This is further translated into productivity and economic loss, an increase in health service expenses and a general decrease in the quality of social wellbeing.
To improve this condition, the municipality administration has the role of implementing solutions to strategically address urban mobility. However, this is a complex task to achieve and normally involves limited resources, which make real-world deployments have a great inherited risk. Thus, decision-making is a task that has to be carefully addressed by different factors and scales.
This thesis approaches multiple tools for analytics on urban mobility using skills in SQL, R and Python, and open-source software such as QGIS for spatial analysis and SUMO (Simulation of Urban Mobility) for microsimulation. The methodology includes the analysis of urban mobility in Montreal from different levels of analysis.
At the macro level, the MTL Trajet dataset provides insight of mobility behaviour of participants through their trip coordinates. Using geometry datasets of quarter and boroughs of Montreal, the analysis is framed and processed via SQL and QGIS. Data visualization is presented in Choropleth maps, Flow maps and Chord diagrams using origin and destination of trips. Supporting processing task such as reverse geocoding to join attributes between datasets are used. The macro analysis helps to identify a primary area of analysis seeking the most transited region. The quarter of René-Lévesque in/and the borough of Ville-Marie are the most accessed areas in this study.
In the meso level, street network information from OpenStreetMap allows making relations among the elements of the area, such as universities and their proximity to pedestrian zones. Resulting maps aid decision-making from a meso perspective, choosing the area of Concordia University as a suitable space for microfocus.
At the micro-level, four areas of opportunity interpreted as transit policy-testing were identified. A custom micro-network and synthetic demand for this area were used to simulate the impacts of these scenarios. The measures tested to improve urban mobility in the area are the restriction of street lanes for specific vehicle types and the inclusion of pedestrian areas. Experimentations with different levels of user modal share and shift are presented.
Results of macro, meso and micro analyses are included to provide recommendations for the administration of the city of Montreal. The inclusion of multiple restrained lanes for buses and high-occupancy vehicles around Concordia University and a pedestrian zone will allow to save time to road users, as long as single-passenger vehicle shifts towards public transit and shared–vehicles.


identifier: Drawel, Nagat  (2019) Model Checking Trust-based Multi-Agent Systems.  PhD thesis, Concordia University.

abstract:
Trust has been the focus of many research projects, both theoretical and practical, in
the recent years, particularly in domains where open multi-agent technologies are applied
(e.g., Internet-based markets, Information retrieval, etc.). The importance of trust in such
domains arises mainly because it provides a social control that regulates the relationships
and interactions among agents. Despite the growing number of various multi-agent applications, they still encounter many challenges in their formal modeling and the verification
of agents’ behaviors. Many formalisms and approaches that facilitate the specifications of
trust in Multi-Agent Systems (MASs) can be found in the literature. However, most of these
approaches focus on the cognitive side of trust where the trusting entity is normally capable
of exhibiting properties about beliefs, desires, and intentions. Hence, the trust is considered
as a belief of an agent (the truster) involving ability and willingness of the trustee to perform some actions for the truster. Nevertheless, in open MASs, entities can join and leave
the interactions at any time. This means MASs will actually provide no guarantee about the
behavior of their agents, which makes the capability of reasoning about trust and checking
the existence of untrusted computations highly desired.
This thesis aims to address the problem of modeling and verifying at design time
trust in MASs by (1) considering a cognitive-independent view of trust where trust ingredients are seen from a non-epistemic angle, (2) introducing a logical language named Trust
Computation Tree Logic (TCTL), which extends CTL with preconditional, conditional, and graded trust operators along with a set of reasoning postulates in order to explore its capabilities, (3) proposing a new accessibility relation which is needed to define the semantics
of the trust modal operators. This accessibility relation is defined so that it captures the
intuition of trust while being easily computable, (4) investigating the most intuitive and
efficient algorithm for computing the trust set by developing, implementing, and experimenting different model checking techniques in order to compare between them in terms of
memory consumption, efficiency, and scalability with regard to the number of considered
agents, (5) evaluating the performance of the model checking techniques by analyzing the
time and space complexity.
The approach has been applied to different application domains to evaluate its computational performance and scalability. The obtained results reveal the effectiveness of the
proposed approach, making it a promising methodology in practice.


identifier: Chandrappa, Dhruva Kumar  (2019) Substrate Integrated Waveguide Based Millimeter Wave Antennas.  Masters thesis, Concordia University.

abstract:
Antennas those operating at millimeter-wave (mm-wave) frequencies (30 - 300 GHz) are more advantageous than operating at less than 6 GHz, due to a reduction in antenna physical dimensions, an increase in the data transfer rate, and reduction in latency. However, the electromagnetic waves propagating in free space at mm-wave frequencies experience significant propagation path loss due to the atmospheric absorption and rain attenuation. Therefore, high-gain antennas are preferred to compensate for path loss and to increase the range of wireless communication. Also, transmission lines such as microstrip, and coplanar waveguides incur high radiation losses at mm-wave frequencies. Hence, to minimize losses, a planar waveguide known as a substrate integrated waveguide (SIW) is preferred. Besides, at mm-wave frequencies, circularly polarized (CP) waves are preferred over linearly polarized (LP) waves as these waves reduce multi-path effects at the receiver.

The objectives of this thesis are to design high-gain linearly, and circularly polarized antennas based on SIW at the mm-wave frequency 30 GHz. The proposed antenna models were designed, simulated, and analyzed using CST software. The antenna prototypes were fabricated and measured for the reflection coefficient, gain, and principal plane radiation patterns. In this thesis, we are proposing two single element antennas, a linear to circular wave polarizer, and an array antenna.

At first, we present, a planar, cylindrical sector-substrate integrated waveguide (CS-SIW) narrow slot antenna. The impedance bandwidth of this antenna is 10.87% which is approximately equivalent to 4 GHz of bandwidth at 30 GHz, and the antenna gain ranges from 8.33 to 8.84 dB within the impedance bandwidth. Further, to improve the gain, an engineered substrate is constructed on top of the CS-SIW slot antenna. The impedance bandwidth of the modified antenna is 10.42% - also, the gain ranges from 10.5 to 11.44 dB over the impedance bandwidth, which implies an increase in the gain from 2.1 to 2.7 dB when compared with the gain of CS-SIW slot antenna. Also, we propose a three-layered meander-line polarizer at 30 GHz which transforms linearly polarized waves to circularly polarized waves for the CS-SIW slot antenna.

Lastly, we present, a 1 × 8 CS-SIW slot antenna array with a superstrate to achieve a high-gain LP antenna. The impedance bandwidth of the antenna is 10%. The gain of the array antenna integrated with a superstrate layer varies from 21.35 to 22.95 dB over the impedance bandwidth.


identifier: Ayoade, Nickesha  (2019) Theoretical Studies On The Design of School Choice Mechanism.  PhD thesis, Concordia University.

abstract:
This thesis consists of three papers on market design which address broadly applicable questions on the design of school choice mechanisms, refugee placement, assignment in entry-level labour markets and similar matching rules.In the  first paper a new family of rules is introduced for many-to-one matching problems, the Preference Rank Partitioned (PRP) rules. PRP rules are Student-Proposing Deferred Acceptance rules where the schools use a choice function based on the students' preference orderings in addition to the schools' strict priority orderings. Each PRP rule uses a choice function which is a function of a fixed partition of both student preference ranks and school priority ranks: the choice function first seeks to select students based on the priority classes and then based on the preference classes. The strict priorities are only used for tie-breaking. PRP rules include many well-known matching rules and some interesting new rules, and we analyze them in this unified framework.
In the second paper we study a new class of matching rules, called Deferred Acceptance with Improvement Trading Cycles (DA-ITC), which start with the DA, and if the DA outcome is not Pareto-efficient then there is an iterated improvement trading cycle phase which allows for Pareto-improvements until a Pareto-efficient outcome is reached. We first revisit EADAM (Kesten, 2010) and show that a simple algorithm which retraces cycles in the DA procedure in a backward order of the rejections is equivalent to the EADAM rule. The new class of DA-ITC rules contains the EADAM and DA-TTC as its two extreme members and exhibits some of their desirable properties.
In the third paper we focus on matching problems where stability need not be satisfied if the violation of priorities is "small," such as when a small priority difference is considered insignificant or when one is willing to consent but only if the priority reversal is small. Based on the degree of stability which specifies what is considered a small priority gap, we define two families of matching rules, the k-Consent rules and the k-DA rules, and explore their attributes.


identifier: Liang, Zhixiang  (2019) Three Essays on Emerging-Market Business Groups.  PhD thesis, Concordia University.

abstract:
Much of the literature on emerging market Business Group (henceforth BG) views the subject in a monochrome ‘paragons or parasites’ dichotomy. In these divergent perspectives, BGs have either a positive or negative effect on economic and institutional development. In the paragon view, BGs emerge as an organizing mechanism to address weak institutions by internalizing market transactions. However, with the development of market-supporting institutions, BGs become less efficient and theory predicts their dissolution and replacement with independent freestanding firms. In the parasite view, BGs emerge but develop strong economic and political power, which are used to block the development of market supporting institutions and support their entrenchment in a stagnant domestic economy, consistent with a middle-income trap.
	The overarching goal of this thesis is to address this dichotomous paradigm and investigate why neither perspective adequately explains the phenomenon of long-lived and efficient BGs. In some economies, BGs emerge, persist, and exhibit increasing efficiency and international competitiveness accompanied by continuing institutional development. More specifically, this thesis aims to offer more nuanced understanding between BGs and their institutional context to understand their resilience during market transitions. The dissertation addresses its theme with three related essays. The first investigates the fundamental source of the emergence and persistence of BG in a shifting institutional environment. Empirical results show that several complementary bundles of management practice differentiate BG affiliates and independent firms in the early phase of development but become less prominent at later stages. The second essay considers the export performance of BG affiliates through organizational capability lens to distinguish between market and nonmarket capabilities. This paper finds support for the hypothesis that BGs utilized superior nonmarket capabilities on enhancing their export performance and suppressing other’s internationalization, but these advantages would be mitigated in a jurisdiction with better political and social support. The third essay complements process theories of emerging market BGs internationalization by considering the structural conditions for successful early-stage internationalization. We propose that international political economy origins have long-lasting path-dependent effects on BG strategy and structure and find strong evidence that BG affiliates in Latin America are less likely to export than are those in Asia.
        The overall implication of the thesis is to present a vibrant picture of BGs in their institutional context. Empirically, this thesis is among the first few to perform empirical research with firm-level microdata BG, collected from the World Bank Enterprise Surveys. The large multi-country dataset allows for a comparative analysis of the issues, while most BG research focuses on single country settings. This thesis contributes a cross-country study using a BG standard definition, thereby adding to a comparative understanding of BG persistence. This thesis also adds to the literature by identifying explicitly non-financial consequences of group affiliation. To sum up, this thesis offers insights for future research on the broader spectrum regarding institutional spheres where BGs associated with and its either positive or negative inter-connections.


identifier: Ghobad Pour, Seyed Reza  (2020) A Linkage between Travel Demand Models and Road Management Systems.  Masters thesis, Concordia University.

abstract: Road congestion is a widespread problem across the world. While certain socioeconomic stratum responds better to measures to encourage the use of public transportation, others exhibit an inelastic behavior and remain loyal to their automobiles. Maintenance and expansion of transportation networks are costly and require annual investments that escape the financial abilities of most governments. Under this paradigm, there is a need to implement optimal decision support systems able to allocate scarce financial resources to accomplish reduced congestion and travel time, and that encourages the use of public transportation. To that end, the traditional approach used to handle Pavements and Road Management was extended in both cases to support a linkage to travel demand models illustrated through two case studies: first of a developing country where an attempt to alleviate road congestion is implemented. Secondly, in a city with good levels of Public transportation where poor support has been granted to the traditional bus system, although they provide the main mean of access to MRT and LRT stations. The proposed approach schedules investments on bus routes through measures to handle traffic and to optimize the surface condition of pavements in an attempt to encourage higher levels of bus ridership.


identifier: Coady, Jesse Watkins  (2019) Capitalism and Dispossession: The Commodification of the Countryside and the "Improvement" of Mi'kma'ki, 1760-1860.  Masters thesis, Concordia University.

abstract: Taking mainland Nova Scotia and Cape Breton Island as its case studies, this thesis attempts to uncover the mechanisms by which the Mi'kmaq were dispossessed of their lands in the eighteenth and nineteenth centuries. Dispossession is here problematized as a process connected to, but distinct from, the imposition of British jurisdiction in Mi'kma'ki following the conclusion of the Seven Years' War. In key respects, dispossession was an inherently local, unpredictable process involving a myriad of actors with disparate motives and interests; at the same time, it was given structural coherence by imperial and colonial land policies, which subjected settlers qua subjects of the Crown to common economic compulsions and constraints. This thesis argues that it was the promotion of capitalist social property relations in particular that provided the greatest impetus for the dispossession of both Mi'kmaq and settlers in this period, giving rise to complex intra- and inter-class dynamics. Although imperial and colonial policies varied widely in their efficacy and application across wide swathes of mostly unpoliceable territory, the promotion of capitalist economic imperatives played a decisive role in facilitating dispossession in even the remotest and most marginal areas. Crucially, it gave rise to widespread squatting, frustrating the authorities' plans for the orderly and profitable settlement of the colony and necessitating a policy of compromise with implicated settlers. By the mid-nineteenth century, authorities largely abandoned their policy of protecting indigenous reserves, opting to sell squatters their improvements in what amounted to a fire-sale of encroached-upon Crown lands.


identifier: Miclette Lamarche, Renaud  (2019) Controlling the air-water behavior of phenolic surfactants and their ω-thiolated derivatives using subphase modification: towards deposition of functional thin films.  PhD thesis, Concordia University.

abstract:
Polyphenolic compounds have the ability to selectively bind metals and certain proteins, properties that can be harnessed for sensing applications. Their analyte binding affinity is partially influenced by the proximity and conformational freedom of the individual phenol moieties. This makes the ability to control the organization of phenol groups an important consideration for the development of phenolic-functionalized thin film coatings. We investigated the approach of using a Langmuir monolayer, pre-organized at the air-water interface to control the lateral spacing upon deposition onto a solid surface. The self-assembly of phenolic surfactants is determined by the strong headgroup interactions: the hydroxyl groups can hydrogen bond with neighboring phenols and the aromatic ring can form π-interactions. We find that the strong, directional interactions lead to the creation of very rigid films that we attribute in large part to the presence of an organized and crystalline phenol headgroup layer. Modification of the subphase pH caused deprotonation of the phenol hydroxyls, which disrupt the organization of the monolayer in two ways: first by increasing the inter-domain charge repulsion and, at high pH, by disrupting the hydrogen bond network yielding a new lateral organization.

In order to deposit the film onto solid support for chemisorb to the surface using gold-thiol chemistry, an ω-thiolated phenolic surfactant was used. The impact of the ω-thiolation on the behavior of the phenol film was investigated. The thiol-terminated surfactant initially forms a film with the same structure and organization as the methyl-terminated surfactant but this phase was found to be metastable and convert to a bent conformation, with both the phenol and the thiol tethered to the water surface, over time. The rate of this interconversion between the condensed phase and bent phases could be controlled using the subphase pH, however high pH can also induce multilayer formation. We demonstrated that spreading the film over a subphase that contains binding analytes of interest, such as poly-L-proline and copper ions, can be used as a strategy to pre-organize the surfactants into the optimal lateral spacing for subsequent binding.


identifier: Niazalizadeh Moghadam, Mojtaba  (2019) Modeling Business Process Workflow of SMEs Using Environment Based Design with a Case Study of Valtech Fabrication Incorporation.  Masters thesis, Concordia University.

abstract:
Small and Medium-Sized Enterprises (SMEs) account for over 95% of firms in most countries. In Quebec, SMEs account for 96% of all businesses. SMEs are important for economic growth and they are strong contributors to productivity. Some of the challenges of SMEs are the lack of financing, difficulties in using technology, constrained managerial capabilities, or inefficient productivity.
Among challenges of SMEs, finance and inefficient productivity can be considered as two of the most important issues that slows down their growth. Finance issues can be referred to as the lack of money in investing in new technologies, hiring competent resources, and investing in new equipment. To improve the financial status of a company and increase the profit, we can either increase the revenue or decrease the expenses. The objective of this project is to target the finance issue as well as inefficient productivity of the SMEs and improve both of them by developing a workflow model. Workflow refers to a method for improving business process management, and an effective workflow can help the decision-makers in an enterprise to develop pathways leading to the reduction of costs and wastes. It employs the Environment Based Design (EBD) methodology which not only designs an effective workflow but also analyses the environment of the business to find the root causes of the issues to help the SMEs improve their finance issue by increasing the operation and production efficiency and effectiveness.


identifier: Rasic, Alis  (2020) Anonymization of Event Logs for Network Security Monitoring.  Masters thesis, Concordia University.

abstract:
A managed security service provider (MSSP) must collect security event logs from
their customers’ network for monitoring and cybersecurity protection. These logs
need to be processed by the MSSP before displaying it to the security operation
center (SOC) analysts. The employees generate event logs during their working hours
at the customers’ site. One challenge is that collected event logs consist of personally
identifiable information (PII) data; visible in clear text to the SOC analysts or any
user with access to the SIEM platform.
We explore how pseudonymization can be applied to security event logs to help
protect individuals’ identities from the SOC analysts while preserving data utility
when possible. We compare the impact of using different pseudonymization functions
on sensitive information or PII. Non-deterministic methods provide higher level of
privacy but reduced utility of the data.
Our contribution in this thesis is threefold. First, we study available architectures
with different threat models, including their strengths and weaknesses. Second, we
study pseudonymization functions and their application to PII fields; we benchmark
them individually, as well as in our experimental platform. Last, we obtain valuable
feedbacks and lessons from SOC analysts based on their experience.
Existing works[43, 44, 48, 39] are generally restricting to the anonymization of
the IP traces, which is only one part of the SOC analysts’ investigation of PCAP
files inspection. In one of the closest work[47], the authors provide useful, practical
anonymization methods for the IP addresses, ports, and raw logs.


identifier: Sumba Toral, Francisco Xavier  (2020) Approximate Bayesian Inference for Count Data Modeling.  Masters thesis, Concordia University.

abstract:
Bayesian inference allows to make conclusions based on some antecedents that depend on prior knowledge. It additionally allows to quantify uncertainty, which is important in Machine Learning in order to make better predictions and model interpretability. However, in real applications, we often deal with complicated models for which is unfeasible to perform full Bayesian inference. This thesis explores the use of approximate Bayesian inference for count data modeling using Expectation Propagation and Stochastic Expectation Propagation.

  In Chapter 2, we develop an expectation propagation approach to learn an EDCM finite mixture model. The EDCM distribution is an exponential approximation to the widely used Dirichlet Compound distribution and has shown to offer excellent modeling capabilities in the case of sparse count data. Chapter 3 develops an efficient generative mixture model of EMSD distributions.  We use Stochastic Expectation Propagation, which reduces memory consumption, important characteristic when making inference in large datasets.

  Finally, Chapter 4 develops a probabilistic topic model using the generalized Dirichlet distribution (LGDA) in order to capture topic correlation while maintaining conjugacy. We make use of Expectation Propagation to approximate the posterior, resulting in a model that achieves more accurate inference compared to variational inference. We show that latent topics can be used as a proxy for improving supervised tasks.


identifier: Ghasemi, Ahmad  (2020) Enhanced Image-Based Visual Servoing Dealing with Uncertainties.  PhD thesis, Concordia University.

abstract:
Nowadays, the applications of robots in industrial automation have been considerably increased. There is increasing demand for the dexterous and intelligent robots that can work in unstructured environment. Visual servoing has been developed to meet this need by integration of vision sensors into robotic systems. Although there has been significant development in visual servoing, there still exist some challenges in making it fully functional in the industry environment. The nonlinear nature of visual servoing and also system uncertainties are part of the problems affecting the control performance of visual servoing. The projection of 3D image to 2D image which occurs in the camera creates a source of uncertainty in the system. Another source of uncertainty lies in the camera and robot manipulator's parameters. Moreover, limited field of view (FOV) of the camera is another issues influencing the control performance.  There are two main types of visual servoing: position-based and image-based. This project aims to develop a series of new methods of image-based visual servoing (IBVS) which can address the nonlinearity and uncertainty issues and improve the visual servoing performance of industrial robots.
The first method is an adaptive switch IBVS controller for industrial robots in which the adaptive law deals with the uncertainties of the monocular camera in eye-in-hand configuration. The proposed switch control algorithm decouples the rotational and translational camera motions and decomposes the IBVS control into three separate stages with different gains. This method can increase the system response speed and improve the tracking performance of IBVS while dealing with camera uncertainties. The second method is an image feature reconstruction algorithm based on the Kalman filter which is proposed to handle the situation where the image features go outside the camera's FOV.  The combination of the switch controller and the feature reconstruction algorithm can not only improve the system response speed and tracking performance of IBVS, but also can ensure  the success of servoing in the case of the feature loss. Next, in order to deal with the external disturbance and uncertainties due to the depth of the features, the third new control method is designed to combine proportional derivative (PD) control with sliding mode control (SMC) on a 6-DOF manipulator. The properly tuned PD controller can ensure the fast tracking performance and SMC can deal with the external disturbance and depth uncertainties.  In the last stage of the thesis, the fourth new semi off-line trajectory planning method is developed to perform IBVS tasks for a 6-DOF robotic manipulator system. In this method, the camera's velocity screw is parametrized using time-based profiles. The parameters of the velocity profile are then determined such that the velocity profile takes the robot to its desired position. This is done by minimizing the error between the initial and desired features. The algorithm for planning the orientation of the robot is decoupled from the position planning of the robot. This allows a convex optimization problem which lead to a faster and more efficient algorithm. The merit of the proposed method is that it respects all of the system constraints. This method also considers the limitation caused by camera's FOV.
  All the developed algorithms in the thesis are validated via tests on a 6-DOF Denso robot in an eye-in-hand configuration.


identifier: Yasoubi, Monazzahalsadat  (2020) An Efficient Hardware Implementation of LDPC Decoder.  Masters thesis, Concordia University.

abstract: Reliable communication over noisy channel is an old but still challenging issues for communication engineers. Low density parity check codes (LDPC) are linear block codes proposed by Robert G. Gallager in 1960. LDPC codes have lesser complexity compared to Turbo-codes. In most recent wireless communication standard, LDPC is used as one of the most popular forward error correction (FEC) codes due to their excellent error-correcting capability. In this thesis we focus on hardware implementation of the LDPC used in Digital Video Broadcasting - Satellite - Second Generation (DVB-S2) standard ratified in 2005. In architecture design of LDPC decoder, because of the structure of DVB-S2, a memory mapping scheme is used that allows 360 functional units implement simultaneously. The functional units are optimized to reduce hardware resource utilization on an FPGA. A novel design of Range addressable look up table (RALUT) for hyperbolic tangent function is proposed that simplifies the LDPC decoding algorithm while the performance remains the same. Commonly, RALUTs are uniformly distributed on input, however, in our proposed method, instead of representing the LUT input uniformly, we use a non-uniform scale assigning more values to those near zero. Zynq XC7Z030, a family of FPGA’s, is used for Evaluation of the complexity of the proposed design. Synthesizes result show the speed increase due to use of LUT method, however, LUT demand more memory. Thus, we decrease the usage of resource by applying RALUT method.


identifier: Dolan, Emilie  (2017) Physiological Effects of Electronic Cigarettes: A Systematic Review and Meta-Analysis.  Masters thesis, Concordia University.

abstract:
Background: Electronic cigarettes represent a new phenomenon in the fight against smoking. While they continue to be marketed both as safer than traditional cigarettes and as potential smoking cessation tools, little is known about their potential physiological effects.
Objectives: The purpose of this systematic review was to provide an analysis of the physiological effects of e-cigarettes in humans.
Methods: A search was conducted by two independent authors using PubMed, SCOPUS, Web of Science and the Cochrane Library electronic databases (until July 24, 2017 ). Inclusion criteria consisted of: English and French language peer-reviewed articles; studies including human participants; objective measurements of physiological responses to active e-cigarette smoking; physiological measures obtained during or post-smoking and compared to baseline measures.
Results: Of the 3101 studies investigated, fourteen studies met the inclusion criteria. These studies indicated that the short-term (4-20 minutes) use of e-cigarettes resulted in decreases in measures of respiratory function such as forced expiratory volume in one second (FEV1), forced vital capacity (FVC), forced expiratory flow (FEF) and exhaled carbon monoxide (eCO); as well as increases in cardiovascular measures such as heart rate and blood pressure. Exposure to e-cigarettes was found to be less harmful than exposure to combustible cigarettes, though not entirely benign.
Conclusions: Based on the current literature, e-cigarettes do not appear to be as harmful as traditional cigarettes. As these devices have only recently become available, it has been impossible to conduct any long-term studies into their repercussions. Further studies are needed to gain an understanding of potential long-term effects.


identifier: Zhou, Mandi  (2020) Pen Neighbour 笔邻: A Research-Creation Approach to Intervening in Short-Term Volunteer Programs in Rural China.  Masters thesis, Concordia University.

format: text video video

abstract:
Education inequality is one of the most pressing concerns in rural China today. Every summer, thousands of volunteers, mostly Chinese highschool and college students, travel from other cities and countries to help fill the education gaps in China by teaching the students. However, as volunteerism becomes more and more popular, the quality of short-term volunteer programs has become questionable, in terms of improving students' academic performance. This research-creation project investigates three critical questions: Are the short-term volunteer
programs in rural China genuinely effective? How can I intervene as a designer? What would be a solution or an alternative to the short-term volunteer programs?
From evaluating Chinese economic disparity to learning from several case studies of volunteer programs in a closer lens, this paper is divided into three parts: the first part paints a picture of the current landscape of short-term volunteer programs in China; the second part of the research explores the potential for a creative intervention through design justice, design for pluriverse, participatory design, and embodiment; lastly, the third part walks through the development of an interactive application entitled Pen Neighbour with generative research methods, such as cultural probe study, participatory observation, surveys, interviews, and user testing.
Based on the research results, short-term volunteer programs do not ultimately fulfill the educational gaps in rural China due to short service periods and a lack of supervision and training. Therefore, the goal of the project is to fill the gaps in traditional short-term volunteer programs in rural China by providing an alternative volunteer approach that incorporates the principle of design justice throughout the research and design process. The participatory research method empowers the students and other stakeholders of the programs by giving them voices. It allows them to make design decisions based upon their opinions and preferences in every step of the research-creation process. Through an iterative design process, Pen Neighbour has evolved from a traditional one-on-one penpal program to an embodied experience on a digital mobile application prototype. The current design of Pen Neighbour prolongs the service period of the volunteer programs by building long-term relationships between the volunteers and the students, one letter at a time. In Pen Neighbour, volunteers are no longer limited to being
trained teachers; instead, they become mentors, friends, big brothers, and sisters with the students. Most importantly, it gives an equal opportunity for both the students and volunteers to design the program and their own Pen Neighbour experience, which is something that
traditional volunteer programs lack.


identifier: Ferguson, Joel  (2020) The Lost Cafeteria: Poems.  Masters thesis, Concordia University.

title: The Lost Cafeteria: Poems

abstract: Taking its cues from the twentieth century life writing of Robin Blaser, Frank O’Hara, William Everson, Sylvia Plath and Alden Nowlan, The Lost Cafeteria is a stylistically shapeshifting bildungsroman-in-verse which examines and attempts to resolve the author’s parochially religious upbringing with his secular, peripatetic adulthood. Exploring the shape of the “I-within-history,” Ferguson mixes confessional lyric poetry with experimental détournements of texts from high and low culture to visit (and revisit) issues of labour, rebellion, family (biological and chosen), class, travel, memory (personal and historical), religion, place, and the meanings of the word “home.”


identifier: Wang, Yuxin  (2020) Creative mid-roll advertising or In-video overlay advertising? The effects of two emerging ad types in Chinese TV series.  Masters thesis, Concordia University.

abstract: Rapid development of online advertising has made advertisers and marketers look at the TV series industry in China. Nowadays, advertisers and marketers are trying new and creative tactics of advertising in Chinese TV series. This study aims to compare these two types of advertising (creative mid-roll and overlay advertising) at intrusiveness levels and seeks to better understand the effects of two creative types of advertising in Chinese contexts; precisely to understand their effects on viewers’ attitudes toward advertising and brands and understand the different effects of advertising between introvert viewers and extrovert viewers and the mediation effect of irritation in influencing the perceived intrusiveness and attitude toward the ad and brand. Results indicate that different from the traditional video and text advertising difference, creative mid-roll advertising and in-video overlay advertising show no difference in intrusiveness levels. In addition, introvert people would perceive higher intrusiveness than extrovert people when people watch advertisements. Mediation effect of irritation is also confirmed in the current study which is partially mediated the relationship between intrusiveness and attitude toward the ad and the brand. When it comes to the managerial implications, the study suggests that in-video overlay advertising is more acceptable for general people so that it should be more considered for the Chinese TV series. Another implication is that advertisers should have awareness of marketing etiquette. They should be more concentrated on customer experience, respecting customers, and protecting customers’ rights.


identifier: Khanmohammadi, Kobra  (2019) Leveraging the Use of API Call Traces for Mobile Security.  PhD thesis, Concordia University.

abstract: The growing popularity of Android applications has generated increased concerns over the danger of piracy and the spread of malware. A popular way to distribute malware in the mobile world is through the repackaging of legitimate apps. This process consists of downloading, unpacking, manipulating, recompiling an application, and publishing it again in an app store. In this thesis, we conduct an empirical study of over 15,000 apps to gain insights into the factors that drive the spread of repackaged apps.  We also examine the motivations of developers who publish repackaged apps and those of users who download them, as well as the factors that determine which apps are chosen for repackaging, and the ways in which the apps are modified during the repackaging process. We have also studied android applications structure to investigate the locations where malicious code are more probable to be embedded into legitimate applications. We observed that service components contain key characteristics that entice attackers to misuse them. Therefore, we have focus on studying the behavior of malicious and benign services. Whereas benign services tend to inform the user of the background operations, malicious services tend to do long running operations and have a loose connection with rest of the code. These findings lead us to propose an approach to detect malware by studying the services’ behavior. To model the services’ behavior, we used API calls as feature sets. We proposed a hybrid approach using static and dynamic analysis to extract the API calls through the service lifecycle. Finally, we used the list of API calls preponderantly present in both malware as well as benign services as the feature set. We applied machine learning algorithms to use the feature set to classify malicious services and benign services.


identifier: Beltayib, Abduladeem ORCID: https://orcid.org/0000-0002-8405-1811 <https://orcid.org/0000-0002-8405-1811>  (2019) Analytical Design Procedures for the Odd Mode of Ridge Gap Waveguide Devices and Antennas.  PhD thesis, Concordia University.

abstract:
The millimeter-wave (mm-wave) band has attracted attention due to its wideband characteristics that make it able to support multi-gigabit per second data rate. Nevertheless, the performance of mm-wave wireless communication systems is restricted due to attenuation loss. Design of mm-wave components and antennas is rapidly growing with the current evolution in the wireless communication systems. However, the traditional waveguide structures such as microstrip, coplanar, substrate integrated waveguide, and rectangular waveguide either suffer from high losses or difficulty in manufacturing at mm-wave band. The ridge gap waveguide (RGW) technology is considered as a promising waveguide technology for the mm-wave band. RGW technology overcomes the conventional guiding structure problems as the wave propagates in an air gap region which eliminates the dielectric loss. Moreover, RGW does not need any electrical contacts, unlike traditional rectangular waveguides. Also, the RGW can be implemented in the printed form (PRGW) for easy integration with other planer system components.

 In this thesis, the use of the odd mode (TE10 (RGW)) RGW to design mm-wave components and antennas is presented. First, a systematic design methodology for the RGW using hybrid PEC/PMC waveguide approximation is presented. This reduces the design time using full wave simulators. The concept has been verified by simulation and experimental measurements. Second, two different methods to excite the odd mode in RGW are studied and investigated. In the first method, a planar L-shape RGW is used where less than -10 dB reflection coefficient is achieved, from 28 to 36 GHz, and more than 93% of the input power has been converted into the odd mode at the output port. The second method uses a magic tee with a shorted sum port and provides a wideband pure odd mode at the output port with reflection coefficient less than -10 dB from 28 GHz to 39 GHz. Other mm-wave components based on odd mode TE10  RGW are designed and presented including a Y-junction power divider and 3 dB forward coupler are designed for the first time in RGW technology. The Y-junction has a wideband matching from 28 to 34 GHz with a reflection coefficient less than -15 dB and the transmission output levels are about -3.3 dB.

 The usefulness of the odd mode RGW lies in the ability to increase the channel bandwidth that has been achieved by designing a dual-mode RGW. A magic tee is used to simultaneously excite the fundamental mode Q-TEM and the odd mode TE10 (RGW) on the ridgeline. The proposed dual-mode RGW performance is verified through simulation and measurement of a back-to-back configuration. The proposed design achieves a matching level less than -10 dB for the two modes over the frequency range from 29 GHz to 34.5 GHz with isolation better than 23 dB. The dual-mode RGW is then used to feed a reconfigurable Vivaldi horn antenna where two different radiation patterns can be obtained depending on the excited mode. The Q-TEM generates a single beam pattern, while the odd mode TE10 (RGW) generates a dual-beam pattern. The maximum gain for the single beam radiation is 12.1 dBi, while it is 10.43 dBi for the dual-beam pattern. The bandwidth of the dual-mode antenna is 25% at 32 GHz with impedance matching less than -10 dB and isolation better than 20 dB.

 Finally, several antennas are presented in this thesis based on the odd mode RGW. A novel differential feeding cavity antenna using the odd mode of RGW is presented. The measured results show good performance in terms of gain, bandwidth, sidelobe level, and cross-polarization. The maximum gain is 16.5 dBi, and the sidelobe level is -17 dB and -13.8 dB, for the E-plane and H-plane, respectively. Moreover, the proposed antenna has low cross-polarization levels of -35 dB in the E-plane and -27 dB in the H-plane. In addition, two 2x1 linear frequency scanning array antennas are designed and implemented using the proposed Y-junction to generate single beam and dual-beam patterns. The beam scan is from -11(degree) to -40(degree) at 28 GHz and 32 GHz, respectively.


identifier: Cui, Xinyu  (2020) The real motivation behind Chinese people’s coffee consumption.  Masters thesis, Concordia University.

abstract:
Chinese market’s prosperity have received a huge amount of attention from marketing
researchers. Entered into China in 1980s, coffee—this totally Western beverage has achieved a huge success in China with the expansion of Starbuck in 168 Chinese cities and is still continuing its business glory in China today (Biederman 2005). Previous studies about Chinese coffee consumption have discussed its development. However, few of them studied the motivation and drivers for Chinese people to consume coffee, especially consuming coffee in the coffee shop. Thus, our study uses the coffee shop as a useful example to illustrate that the function of luxuriousness together within Western products would be an important determinant influencing Chinese consumers’ purchase intention and willingness to pay more for a Western product with luxuriousness value. Likewise, our study fills the theoretical gap to understand the real motivation for Chinese consumers’ coffee consumption. Our findings suggest that the Perceived luxuriousness of the physical environment of the coffee shop in China induce both higher perceived quality of coffee and consistent self- congruency, which lead to positive store attitudes, thus increasing willingness to pay a premium price for the coffee. In addition, we find that perceived luxuriousness of the physical environment of the coffee shop would induce a high level of self-congruence for high cosmopolitan consumers, compared with those who are low cosmopolitan. The managerial implication of this study suggests that the establishment of luxuriousness in the physical setting of a coffee shop would be crucial to attract consumers’ attention and that managers should use premium pricing strategy to ensure the superior value of coffee that fit with coffee consumers’ identity in China.


identifier: Dinh, Phuc  (2020) Cooperative Communications for 5G Wireless Networks and Beyond.  Masters thesis, Concordia University.

abstract: Cooperative communication is an appealing technique stemming from the information-theoretic notion of cooperative diversity and having gradually evolved into a mainstream design paradigm in 4G LTE-Advanced. By exploiting cooperation among multiple transmission/reception nodes the technique reveals tremendous benefits, both in theoretical research and practical deployment, to enhance network performance in terms of throughput, reliability, latency, and network coverage. Due to these desirable attributes, it is expected that the technique will continue to be utilized in the coming generations of wireless networks. However, a major challenge to enable cooperative communication in the context of 5G and beyond is the advent of new wireless technologies and network architectures. The emergence of these technologies, on the one hand, enables a plethora of new applications. On the other hand, they entail new network operational constraints, which hinders the cooperation among network nodes. To address this challenge, it is crucial to study cooperative communication in specific network scenarios where these new technologies are employed to gain new insights their impact on in-network cooperation. Motivated by this, the thesis studies the role of cooperative communication in two futuristic network scenarios, encompassing two novel wireless technologies, namely non-orthogonal multiple access (NOMA) and unmanned aerial vehicles (UAVs).


identifier: Torkaman Rashid, Alireza  (2019) Seismic Response of Building Frames Controlled using Semi Active Multiple Tuned Mass Dampers.  Masters thesis, Concordia University.

abstract:
Abstract
Seismic Response of Building Frames Controlled using Semi Active Multiple Tuned Mass Dampers
Alireza Torkaman Rashid

Earthquakes induce lateral forces on buildings that could result in damage and potential for collapse of the structures. Therefore, it is necessary to control and design the structures for resisting the forces due to ground motions. Various energy dissipating systems have been developed and used in the past. The application of the Tuned Mass Damper (TMD) has been proven to be effective in tall buildings for the control of vibrations due to wind or earthquake. In this research, for better performance of buildings, Multiple Tuned Mass Damper (MTMD) distributed in different floors of a building has been used and the seismic performance of the building has been studied. A modal analysis has been conducted and the TMDs were placed in a structure and tuned based on its dominant modes. Furthermore, the influence of the distribution of the mass on different levels of a structure has been studied. It is found the MTMDs are very effective in controlling the vibration of a building and compared to a single TMD placed at the top floor. To further improve the performance of a building frame with MTMDs, multiple Magnetorheological dampers (MR dampers) have been paired with each of the MTMDs to create a semi-active system of Semi-Active Multiple Tuned Mass Damper (SAMTMD). While application of MTMDs were explored by other researchers, the use of SAMTMD is a novel concept introduced in this thesis. The seismic demands of the structure including displacement, velocity, acceleration, and the energy dissipating capacity of the structure have been significantly improved with the SAMTMD system.


identifier: Mortazavi, Mehrzad  (2020) Sample Re-weighting for Replay-based Continual Learning in Neural Networks.  Masters thesis, Concordia University.

abstract: Artificial intelligence empowered by neural networks (NNs) has tremendously improved the state-of-the-art results in various domains of applications over the past years. Inspired by human intelligence, there has been a growing interest in the real-world learning settings that pose multiple challenges to the learning agents. Continual learning (CL) is a learning paradigm in which the agent learns new tasks continually from a never-ending and non-stationary stream of data. A CL agent should be plastic enough to learn new tasks, while stable enough not to forget acquired knowledge of previous tasks; in a severe case, the latter situation is called catastrophic forgetting. Replay-based CL methods try to retain the performance by rehearsing stored raw input data or generated samples of the previous tasks. Another challenging situation for ML agents is to gain an acceptable overall performance on skewed data distribution of imbalanced datasets. In this thesis, for the first time in the literature, we analyze the performance of replay-based CL methods on imbalanced datasets in class-incremental scenario. Moreover, we suggest a new application of an adaptive sample re-weighting strategy called Meta-Weight Net for replay-based CL methods. Meta-Weight Net trains a NN to estimate the sample weights based on their respective loss value, which will define the adaptive weighted loss function. Our experiments show that using this strategy not only improves performance over an imbalanced dataset but also can help with more complex datasets where the data is balanced.


identifier: La Braca, Franco ORCID: https://orcid.org/0000-0001-5365-9106 <https://orcid.org/0000-0001-5365-9106>  (2020) Comparison of Student Learning in Traditional Physics Labs and Labatorials.  Masters thesis, Concordia University.

abstract: Traditional, cookbook physics labs are often associated with student dissatisfaction and superficial applications, and are known to leave students with fragmented knowledge. As an alternative, we examine labatorials, a conceptually driven approach to labs. In particular, we develop labatorials to compare with traditional labs in terms of students’ learning experience and the quality of their conceptual learning. In the context of Concordia University’s introductory experimental mechanics course, we collect data spanning semi-structured student and TA interviews, class observations, TA surveys, post-test and final exam scores and responses, and student writing products. Upon analysis and triangulation, we find that due to the scaffolding present in labatorials, students typically exhibit a high degree of collaboration and engagement with the material in a low-pressure environment, which allows students to focus on the learning. Students in traditional labs have a tendency to rely on step-by-step instructions and focus on avoiding errors, which may inhibit their conceptual learning. Although the average final exam scores of the labatorial and traditional groups exhibit no significant difference (p = 0.196), differences do exist for certain question types; namely, traditional lab students tend to perform better on questions involving standardized processes or simple, memorization-based calculations, while labatorial students tend to perform better on conceptual questions.


identifier: Kesserwan, Nader  (2020) Automated Testing: Requirements Propagation via Model Transformation in Embedded Software.  PhD thesis, Concordia University.

abstract:
Testing is the most common activity to validate software systems and plays a key role in the software development process. In general, the software testing phase takes around 40-70% of the effort, time and cost. This area has been well researched over a long period of time. Unfortunately, while many researchers have found methods of reducing time and cost during the testing process, there are still a number of important related issues such as generating test cases from UCM scenarios and validate them need to be researched.
As a result, ensuring that an embedded software behaves correctly is non-trivial, especially when testing with limited resources and seeking compliance with safety-critical software standard. It thus becomes imperative to adopt an approach or methodology based on tools and best engineering practices to improve the testing process. This research addresses the problem of testing embedded software with limited resources by the following.
First, a reverse-engineering technique is exercised on legacy software tests aims to discover feasible transformation from test layer to test requirement layer. The feasibility of transforming the legacy test cases into an abstract model is shown, along with a forward engineering process to regenerate the test cases in selected test language.
Second, a new model-driven testing technique based on different granularity level (MDTGL) to generate test cases is introduced. The new approach uses models in order to manage the
complexity of the system under test (SUT). Automatic model transformation is applied to automate test case development which is a tedious, error-prone, and recurrent software development task.
Third, the model transformations that automated the development of test cases in the MDTGL methodology are validated in comparison with industrial testing process using embedded software specification. To enable the validation, a set of timed and functional requirement is introduced. Two case studies are run on an embedded system to generate test cases. The effectiveness of two testing approaches are determined and contrasted according to the generation of test cases and the correctness of the generated workflow. Compared to several techniques, our new approach generated useful and effective test cases with much less resources in terms of time and labor work.
Finally, to enhance the applicability of MDTGL, the methodology is extended with the creation of a trace model that records traceability links among generated testing artifacts. The traceability links, often mandated by software development standards, enable the support for visualizing traceability, model-based coverage analysis and result evaluation.


identifier: Charbonneau, Ariane  (2020) Oddkins vignettes: A case study of Human-Robot Kinship in Science-Fiction manga through Kazuo Umezu’s I Am Shingo.  Masters thesis, Concordia University.

abstract: This thesis argues that manga as a medium is a remarkably appropriate way of exploring the continuous thread of Haraway’s theorization of kinship and filiations without blood relating. Manga, per its formal characteristics, has an inherent intricacy, drawing from words, illustration and cinema to create a whole that is more than the sum of its parts. To demonstrate this, we explore a case study of science-fiction manga (I Am Shingo) through the lens of Donna J. Haraway’s body of work. More specifically,  it uses the concept of “ oddkins ”, borrowing from Haraway’s Cyborg theory and her Companion Species theory, to articulate these rich, loaded relationships. Additionally, we invoke Haraway’s later works, where the focus is not only on hybridity and heterogeneity, but on the links that develop within the different beings inhabiting a common space and their inevitable interactions.  This thesis is constructed around one case study, looking at Kazuo Umezu’s I Am Shingo (1982). Through this tale of a robotic offspring trying to reunite its star-crossed lover parents, we explore examples of oddkins as Shingo encounters allies from various walks of life and interfaces with them. Addionally, we will discuss the benefits Haraway’s body of work can have on manga studies.


identifier: Fernandes de Oliveira Sobrinho, Vilmar  (2020) Dispensationalism: A Case Study of Matthew 24 and Its Reception in Brazil.  Masters thesis, Concordia University.

abstract: Dispensationalism is a well-known and widely held eschatological framework among contemporary evangelicals. It has, however, been little explored in academia, possibly due to the wide range of interpretations it provides for understanding eschatological events. Texts such as the “eschatological discourse” of Matthew 24 give rise to the belief in a particularly grim future. In this work, research was conducted on the history of the interpretation of Matthew 24 as well as its reception in the social and political life of Brazil. It is possible to observe a relationship of cause and effect concerning the lack of knowledge about eschatology and popular imagination about the meaning of Matthew 24. The conclusion that is reached is that a “theology of fear” results from adopting a dispensationalist perspective which finds itself in opposition the Christian message of hope.


identifier: Persram, Ryan  (2020) Trust within Sibling Relationships: Predicting Psychosocial Well-Being in Early Adolescence.  PhD thesis, Concordia University.

abstract: Sibling relationships are a unique and critical context through which we can investigate early adolescent development and well-being. Positive sibling relationship qualities (e.g., warmth) are implicated in many facets of adolescents’ lives; for example, positive relationships promote positive self-worth (Noel et al., 2018) and fewer internalizing and externalizing symptoms (e.g., Dirks et al., 2015). An important, yet understudied, relational feature reflects the degree to which early adolescents feel that they can trust their sibling. Specifically, the extent to which they can rely on the behaviours or promises made by a sibling can have important implications for the sibling relationship and adolescent well-being. As such, the present three studies investigated the role of sibling trust and its value within the context of the sibling relationship and for adaptive and maladaptive adjustment. Study 1 reports on a new self-report measure of sibling trust that addressed the methodological limitations of previous measures of trust and examined its association with sibling relationship satisfaction. Findings revealed a two-factor structure based on reliability trust and trust honesty, which were each positively predictive of sibling relationship satisfaction. Regarding birth order, the effect of trust honesty was stronger for older siblings than younger siblings. Study 2 examined the predictive value of sibling trust on adolescent general self-worth in a cross-cultural sample from Canada and Colombia. Results indicated that sibling trust was positively predictive of general self-worth, social competence, and academic competence. Further, the effect of sibling trust on social competence was stronger for boys than girls, whereas no significant cultural differences were observed. Study 3 investigated the protective function of sibling trust on adolescent perceptions of depressed affect and the intolerance of uncertainty over a two-month period. Reliability trust and trust honesty differentially predicted the stability of depressed affect, such that high reliability trust weakened the association while high trust honesty strengthened it. Together, findings are discussed relation to established theoretical frameworks regarding the multidimensionality of trust (Rotenberg, 2010) and relationships theory (Hinde, 1979). Generally, these results supported the relative value of trust within the sibling relationship and its importance for maintaining a satisfactory relationship and individual well-being.


identifier: Jordon, Joel  (2020) Respecting the Autonomy to Reflect: Entitlement, Trust, and Computer Testimony.  Masters thesis, Concordia University.

abstract: The beliefs that we receive through computer use and our trust in their sources might be justified or not, and I will argue that they are not prima facie justified if they threaten our autonomy to reflect afterward. Drawing on Brandom, I will talk about justification in terms of being “entitled” to a belief as a social status instituted by a practice of mutual recognition. I will argue that a lack of mutual recognition may create contexts where we either do not trust, preventing beliefs from being shared, or misplace trust, threatening that social norms may be one-sidedly enforced on our thought and behavior. When mutual recognition is achieved, on the other hand, we have a prima facie entitlement to accept beliefs and trust sources because it ensures respect for our autonomy to reflect, up to having second thoughts about our beliefs and retracting our trust. In light of my analysis of entitlement as a social status, failures of entitlement in our contemporary belief sharing practices that use intermediaries like computers will be able to be identified as historically situated failures of mutual recognition among communities. I will suggest that computers and software have to be designed for, and backed by, communities in which mutual recognition can already succeed. Then they could be tools facilitating contexts in which trust between users and programmers could develop at the same time as their autonomy to form and reform their own beliefs to think and act for themselves is respected.


identifier: Gordon, Bryan J.  (2019) Hoarding and the Cult of Money.  Masters thesis, Concordia University.

title: Hoarding and the Cult of Money

abstract:
As a category of psychological diagnosis, Hoarding Disorder has spawned a conception of “the
hoarder” marked by social exclusion, a habitual urge to possess objects, and an apparent
difficulty in disposing them. Against this limited definition, which stems from a lack of long-term historical and social awareness among scholars of hoarding disorder, my work asks, How is
hoarding logical? Can we read hoarding as non-pathological or adaptive? What kind of monuments and record have historical hoarders left behind? Proceeding from the longer etymology of the word, hoard, and coupled with oral history interviews drawn from my own life, this thesis recasts “hoarding” as more complex than the current paradigm implies, pertaining to the rise of capitalism, commodity fetishism, and broader forms of socio-economic reciprocity which preceded and responded to formal and informal empire.

Supported by historical documents from major thinkers in political economy, classical Liberalism, Marxism, Social Anthropology, and Neoliberalism, alongside periodical documents from nineteenth and twentieth-century Britain and the United States, I argue that hoarding among the poor and socially vulnerable, such as those affected by post-colonialism, deindustrialization, austerity, statelessness, etc., may be reread as a mode of economic survival and social investment, if the economic idiosyncrasies of an individual hoarder’s subjective lifeworld and context are taken into consideration. In tandem with this line of reasoning, I argue that hoarding is a spectrum of behavior that also includes more ‘normative’ behaviors of the super-wealthy, including cash and land hoarding.

This thesis uses oral history, with cultural, anthropological, and literary sources, to shift the language around hoarding and to present it as an underlying logic of capitalism, as a mediator of interpersonal and family relationships, and as a dangerous extension of twentieth-century empire, functioning through hegemonic, legal, but deeply unethical institutions and financial tools such as major accountancy firms, central banks, international tax havens, and international corporations. Using sentimental objects from personal collections, I situate myself as embedded within history, and at the cusp of different economic and cultural worlds, wherein objects are read as unique signifiers of memory and meaning.


identifier: Mukhtarli, Kanan  (2020) Machine learning for homogeneous grouping of pavements.  Masters thesis, Concordia University.

abstract:
Abstract

Machine learning for homogeneous grouping of pavements.
Kanan Mukhtarli

Rapid pavement deterioration is a major problem in areas with harsh weather conditions or high traffic loading. Despite many studies focused on the pavement management systems, there is not, to the date, a robust method explaining how to process large amounts of pavement data to create homogeneous groups for rehabilitation-related decision making. This thesis employs machine learning to develop an approach capable of partitioning pavement data with a close response to casual factors like traffic and weather conditions and considering its performance through international roughness index and deflections. Two different methods: K-means and Self Organizing Maps (SOM) clustering techniques were tested to understand the correlation between daily factors and pavements deterioration. The goodness of clustering was tested using extrinsic and intrinsic evaluation methods. It was concluded from the results that SOM clustering provided better results as it relies on a soft clustering method where one point can represent two clusters at the same time. Moreover, it became obvious from the methodology that including the previous year’s data has very little to no effect on homogeneous groups. Techniques discussed and developed in this study can help road asset managers with decision making for the maintenance and rehabilitation of pavement. Moreover, future researchers can use the results of this study to further develop the idea of building decision support systems for pavement rehabilitation.


identifier: Guerrero López, Cristóbal  (2020) Self-Adaptive Model-Based Control for VAV Systems.  Masters thesis, Concordia University.

abstract: In North America one of the main users of primary energy are buildings, where HVAC equipment operation is the largest consumer of total energy by end use. This has triggered the need to develop better active strategies and building technologies for the enhancement of HVAC equipment performance. Great examples of solutions that large commercial and institutional buildings adopted, were the widespread use of Building Automation Systems (BAS), and approaches like Variable Air Volume (VAV) systems for ventilation, which allow for better part load regulation, reduction of energy consumption and building operation costs, without compromising occupant comfort or safety. But despite all these improvements, most BAS still rely on conventional control methods like rule based on-off control paired with Proportional Integral Derivative (PID) loops, which are single input single output (SISO) models that are not suitable for the complexities of the multivariable requirements of building systems. These outdated strategies have been estimated to annually waste up to 30% of building’s energy.  To mitigate these issues the research community has strongly endorsed the use of more advanced and proven effective control methods such as Model-Based Control (MBC), in which abundant work has been done for the supervisory level control like optimal start/stop, setpoint reset scheduling, etc. However, little attention has been given to local level control where PID control remains the chief workhorse of HVAC systems. Mainly because of the difficulties of creating models, as well as the lack of research regarding the implementation of mechanisms required for continuous calibration (also known as adaptability) of model parameters as they start to drift away from their initial values due to system changes or deterioration, which challenges the reliability of any MBC approach. For such reasons the present body of work was conceived to design a practical methodology for a self-adaptive MBC and field data driven approach to improve VAV systems energy efficiency, based on the Total Air Volume (TAV) control method by modifying the shortcomings of  its modeling, adaptability and control strategy procedures. Using a regular VAV system inside a high-rise institutional building as an experimental testbed for the proof of concept of this methodology. The results of the test demonstrated that the self adaptive field calibrated TAV method can match and exceed the capabilities of PID control, by improving response time, offset, and above all energy efficiency, were an average 56% of energy consumption was achieved in contrast to the conventional duct static pressure PID control.


identifier: Harb, Hassan  (2019) Spectral Comparison Theorems for the Klein-Gordon equation in d>=1 dimensions.  PhD thesis, Concordia University.

abstract:
We first study bound-state solutions of the Klein--Gordon equation                                    φ"(x)=[m^2-〖(E-V(x))〗^2]φ(x), for vector potentials which in one spatial dimension have the form V(x) = vf(x), where f(x)≤0 is the shape of a finite symmetric central potential that is monotone non-decreasing on [0, ∞) and vanishes as x⟶∞, and v>0 is the coupling parameter.

We characterize the graph of spectral functions of the form v= G(E) which represent solutions of the eigen-problem in the coupling parameter v for a given E: they are concave, and at most uni-modal with a maximum near the lower limit E = -m of the energy E ∈ (-m, m). This formulation of the spectral problem immediately extends to central potentials in d > 1 spatial dimensions. Secondly, for each of the dimension cases, d=1 and d ≥ 2, a comparison theorem is proven, to the effect that if two potential shapes are ordered f_1(r) ≤ f_2(r), then so are the corresponding pairs of spectral functions G_1(E) ≤ G_2(E) for each of the existing eigenvalues. These results remove the restriction to positive energies necessitated by earlier comparison theorems for the Klein--Gordon equation by Hall and Aliyu. Corresponding results are obtained when scalar potentials S(x) are also included.

We then weaken the condition for the ground states by proving that if                             ∫_0^x▒〖[f_2 (t)- f_1 (t)]φ(t)dt≥0〗, the corresponding coupling parameters remain ordered, where φ_i= 1, or φ_i is the bound state solution of the Klein--Gordon equation with potential V_i, i = 1, 2. These results are valid for any energy E ∈ (-m, m)., but they are restricted to the ground states.

We finally present a complete recipe for finding upper and lower spectral bounds for both bounded and unbounded potentials, and we exhibit specific result for the applications for the Woods-Saxon, Gaussian, sech-squared, and Yukawa potentials in dimensions d = 1 and d = 3.


identifier: Parent, Jeffrey  (2020) This Bygone Route.  Masters thesis, Concordia University.

title: This Bygone Route

abstract: This Bygone Route is a strange, vaguely autobiographical, archaeology of the grand and the intimate that presupposes the worlds we occupy— often taken for granted as banal, safe, assumed known— are fundamentally grounded upon substrata of numbing nostalgia and fractured empathy. My work weaves through  natural and constructed spaces rendering these zones eerie, uncanny, strange, occupied by figures both human and animal that are unsettled and unsettling; a challenge to insulating narratives of control, routine, and safety. My poems are occasionally landmarked by familiar artifacts of analog technostalgia: telephone booths, answering machines, instant cameras and other such devices. These objects persist on the fringes of our contemporary moment as charming anachronisms but within these poems they are instilled with eerie prominence, ironically reactivated against the dulling energies of nostalgia and materialism. This Bygone Route is an implication, that the personal and collective histories we celebrate and revere are often rooted in the loam of our darker instincts, our most troubling tendencies, that what gives shape to our most precarious Now. This Bygone Route is a fragmentary map to unstable futures that we cannot expect or prepare for. Not exactly.