identifier: Stopnicki, Brandon ORCID: https://orcid.org/0000-0003-4713-683X <https://orcid.org/0000-0003-4713-683X>  (2019) Glycogen Dynamics in Proliferating Human Helper T Cells.  Masters thesis, Concordia University.

abstract: The immune system protects the body against infections and cancer. A type of lymphocyte called “helper T cell” plays a vital role in coordinating immune responses. Helper T cells are arguably the most important type of immune cell as they are required for almost all adaptive immune functions. T cells play a vital role in the adaptive immune system, however, very little is known about their metabolic pathways. When presented with an antigen, helper T cells proliferate, differentiate and produce cytokines. The activation of helper T cells is metabolically demanding. T cells require large amounts of glucose from their environment as they proliferate. Glycolytic by-products support rapid cell division through the building of biomass. Systematically, excess glucose is stored in the liver in the form of glycogen, but there is growing evidence that glycogen is found in non-hepatic cells as well. With an increase in glucose uptake in helper T cells, surplus must be stored for later use. Currently, there is very little knowledge on the role of glycogen dynamics in helper T cells. I hypothesized that glycogen is important in helper T cell proliferation and cytokine production. I demonstrated that isolated human helper T cells accumulated glycogen upon activation. Activated T cells accumulated a greater amount of glycogen as compared to non-activated cells (p<0.0001). The enzyme α-amylase, added as a control, digested glycogen and reduced the glycogen signal. Inhibition of glycogen breakdown significantly attenuated proliferation and had a trend to decrease pro-inflammatory cytokine IL-17A production in activated peripheral blood mononuclear cells. This is among the first accounts of glycogen dynamics in helper T cells. It is important to study helper T cells because they are implicated in autoimmune diseases and immune deficiencies. This newfound understanding on how helper T cells manage their metabolic needs during an immune response could aid in the development of immunomodulatory treatments.


identifier: Pereira, Carlos A  (2019) Analysis of High-Order Element Types for Implicit Large Eddy Simulation.  Masters thesis, Concordia University.

type: Thesis NonPeerReviewed

abstract:
The use of high-order schemes continues to increase, with current methods becoming more robust and reliable. The resolution of complex turbulent flows using Large Eddy Simulation (LES) and Direct Numerical Simulation (DNS) can be computed more efficiently with high-order methods such as the Flux Reconstruction (FR) approach. We make use of the implicit form of LES, referred to
as ILES, in which the numerical dissipation of the spatial scheme passively filters high-frequency modes and no subgrid scale turbulent model is explicitly implemented. Therefore, given the inherent three-dimensional behaviour of turbulent flows, it is important to understand the spectral characteristics of spatial discretizations in three dimensions. The dispersive and dissipative properties
of hexahedra, prismatic and tetrahedral element types are compared using Fourier Analysis. This comparison is performed on a per degree of freedom basis to assess their suitability for ILES in terms of computational cost. We observe dispersion relations that display non-smooth behaviour for tetrahedral and prismatic elements, with the presence of jumps in the solution modes. Semilogarithmic
plots of the numerical error are presented. We observe that the amount of numerical dissipation and dispersion added by hexahedral elements is the least, followed by prisms and finally tetrahedra. We validate our analysis comparing results obtained on computational domains with comparable computational cost against DNS data. Hexahedral elements have the best agreement with the reference data, followed by prismatic and finally tetrahedral elements, which is consistent with the spectral analysis.


identifier: Melian-Morse, Alejandra  (2019) Caring with the Trouble: Chasing the freedom ideal through the American Southwest.  Masters thesis, Concordia University.

abstract: This ethnography of the outdoor education program Cottonwood Gulch looks closely at the way participants in the program pursued a particular ideal of freedom through their activities over a summer. Much of the Gulch’s programming closely mirrors the mythology of the Wild West depicted across pop culture in movies, stories, music, etc. which all contain the freedom ideal at their cores. However, Cottonwood Gulch’s version of the Wild West myth approaches freedom differently. Over the course of their time at the Gulch, participants come to understand the precarious nature of their place in that environment, and the ecological entanglement that they are a part of. They approach their relationship to the Southwest as a caring one. Having understood the part they play in the ecology of the area, they must care for it. Their care is expressed through labour, affect, and politics, though in some areas the program was more willing to lean into their responsibilities of care than in others. The freedom ideal is complex and often problematic, and looking at the way Cottonwood Gulch stayed (or did not) with the trouble of that complexity was key to understanding its relationship with the Southwest.


identifier: Hamedi, Mohsen  (2019) Stabilizing Filters for High-Order Implicit Large Eddy Simulation.  Masters thesis, Concordia University.

abstract: High-order Flux Reconstruction (FR) schemes can simulate unsteady turbulent flows using Large Eddy Simulation (LES) and Direct Numerical Simulation (DNS) in the vicinity of complex geometries. The application of FR schemes can be limited by non-linear instabilities, related to oscillatory behaviour of the element-wise numerical solution, causing nonphysical solutions. In this study, filtering is studied for hexagonal element types and solution polynomial of degrees 3, 4, and 5 at different Mach numbers ranging from 0.1 to 0.5. A new exponential filtering function is applied globally to all elements and artificially damps high-frequency oscillations to improve numerical stability. Numerous numerical tests have been performed to investigate different parameters in the exponential filtering function. The optimum set of these parameters is obtained such that the highest solution polynomial modes are damped while the lower ones remain untouched to preserve accuracy. The solution polynomial is filtered after each time step; however, the filtering operator is defined, through the concept of characteristic time, to be independent of the time-step size. The exponential filter has been implemented and rigorously studied to evaluate its accuracy. To verify the order of accuracy, advection of an isentropic vortex has been analyzed. To study accuracy for LES, the Taylor-Green vortex test case is studied as a free turbulent flow. Finally, a previously unstable wall-bounded turbulent channel flow test case along with a NACA0020 airfoil at high angle of attack are considered to study the effects of the proposed filtering on stability and accuracy of practical applications.


identifier: Ma, Yan  (2019) A Study on Reactive and Proactive Push-Pull/Make-Before-Break Defragmentation For Dynamic RMSA.  Masters thesis, Concordia University.

abstract:
In this thesis, we investigate several defragmentation techniques, with both proactive and reactive triggering strategies, in the context of dynamic Routing, Modulation and Spectrum Assignment
(RMSA) in optical flexible networks.

Proactive defragmentation is executed periodically or according to some fragmentation degradation thresholds in order to maintain spectral defragmentation at an acceptable level, the defragmentation
is independent of the request connection events. Reactive defragmentation, on the other hand, is performed when a new request is blocked due to insufficient spectral resources. In the
context of dynamic traffic in a flexible optical network, we looked into different combinations of proactive/reactive push-pull and make-before-break defragmentations.

Extensive numerical results show that reactive push-pull defragmentation performs quite well in terms of network throughput and request blocking ratio. Consequently, it is efficient in order
to improve network throughput. For proactive push-pull defragmentation, we investigated two different triggering events, namely, time-driven and throughput-driven. We observed that both
triggering strategies have a good performance on maintaining an efficient spectrum usage in networks. Throughput-driven strategy performs better when the network is heavily loaded, whereas
time-driven strategy is a better option when the network is less loaded.


identifier: Zoghi, Milad  (2019) Role of defects comprise of antidot, Boron/Nitride doping, and uniaxial strain on the electronic/transport properties of GNR, and CNT based RTD devices.  Masters thesis, Concordia University.

abstract: Silicon technology has been the main driving force for miniaturizing electronic device dimensions to reduce cost and improve performance. However, Silicon industry is reaching to fundamental limits that size shrinking trend cannot be continued. Hence, alternative low dimensional materials such as Graphene nanoribbons (GNRs) and Carbon nanotubes (CNTs) have attracted great amount of attention to be used in the future electronic devices. Although, GNRs and CNTs carry promising electronic and transport characteristics, additional flexibility and control over fundamental properties like band gap level is highly desirable. In this thesis, three kinds of defects comprise of antidots, Boron Nitride (BN) doping, and uniaxial strain are used to modify intrinsic properties of GNRs and CNTs. Using Tight Binding (TB) with accompany of Non-equilibrium Green Function (NEGF), it is found that pristine properties of AGNR and ZCNT such as band gap can be modulated upon introduction of periodic antidot, BN defect topologies. Next, novel ZCNT RTD platform is designed by mean of defects, showing potential applications of defected ZCNT in fundamental electronic components such as RTDs. In addition, role of uniaxial strain on the performance of two AGNR RTD platforms is examined. Width-modified and field-modified AGNR RTD platforms go under both local and whole-body uniaxial strain. The analysis manifests that Peak to Valley Ratio (PVR) might be totally lost if imposed whole-body strain is strong enough. However, local strain can either totally damage the PVR or improve it up to 7 times, depending on the type of strain and utilized platform. As a result, AGNR RTDs may not be considered as the ideal candidates for the flexible electronics since their properties are subject to intense variation upon mechanical deformation. This mechanically dependent performance of AGNR RTDs would be promising in design of motion-based sensors.


identifier: Alipour, Hanieh  (2019) Model-Driven Machine Learning for Predictive Cloud Auto-scaling.  PhD thesis, Concordia University.

abstract:
Cloud provisioning of resources requires continuous monitoring and analysis of the workload on virtual computing resources. However, cloud providers offer the rule-based and schedule-based auto-scaling service. Auto-scaling is a cloud system that reacts to real-time metrics and adjusts service instances based on predefined scaling policies. The challenge of this reactive approach to auto-scaling is to cope with fluctuating load changes. For data management applications, the workload is changing and needs forecasting on historical trends and integrating with auto-scaling service. We aim to discover changes and patterns on multi metrics of resource usages of CPU, memory, and networking. To address this problem, the learning-and-inference based prediction has been adopted to predict the needs prior to provision action.

First, we develop a novel machine learning-based auto-scaling process that covers the technique of learning multiple metrics for cloud auto-scaling decision. This technique is used for continuous model training and workload forecasting. Furthermore, the result of workload forecasting triggers the auto-scaling process automatically. Also, we build the serverless functions of this machine learning-based process, including monitoring, machine learning, model selection, scheduling as microservices and orchestrating these independent services by platform, language orthogonal APIs. We demonstrate this architectural implementation on AWS and Microsoft Azure and show the prediction results from machine learning on-the-fly. Results show significant cost reductions by our proposed solution compared to a general threshold-based auto-scaling.

Still, there is a need to integrate the machine learning prediction with the auto-scaling system. So, the deployment effort of devising additional machine learning components is increased. So, we present a model-driven framework that defines first-class entities to represent machine learning algorithm types, inputs, outputs, parameters, and evaluation scores. We set up rules for validating machine learning entities. The connection between the machine learning and auto-scaling system is presented by two levels of abstraction models, namely cloud platform independent model and cloud platform specific model. We automate the model-to-model transformation and model-to-deployment transformation. We integrate model-driven with a DevOps approach to make models deployable and executable on a target cloud platform. We demonstrate our method with scaling configuration and deployment of two open source benchmark applications - Dell DVD store and Netflix (NDBench) on three cloud platforms, AWS, Azure, and Rackspace. The evaluation shows our inference-based auto-scaling with model-driven reduces approximately 27% of deployment effort compared to the ordinary auto-scaling.


identifier: Ata, Soraya  (2019) The Small, Imperfect Cinema of Afghanistan – Through the Work of Roya Sadat.  Masters thesis, Concordia University.

abstract:
Abstract
The Small, Imperfect Cinema of Afghanistan - Through the Work of Roya Sadat

This thesis investigates Afghan cinema, reborn two decades ago with the establishment of new modes of governance and influenced by all the changes this brought. Following Teshome H. Gabriel, the project examines Afghan cinema according to three core means of investigation, as laid out in his critical Third World film theory: text, production and reception. It then supplements Gabriel’s schema with an analysis of the importance of education. After the fall of the Taliban, Afghanistan’s post-conflict reconstruction and transition has been significantly shaped by neo-liberal economic policies that have strongly impacted its fragile film industry, as well as the country at large and its people’s lives. This thesis looks closely at the current infrastructures for cinema in Afghanistan via the journeys that filmmaker Roya Sadat has made through them and the circumstances under which her films have been made. It focuses on the management of complex forms of technical production, the mobilization of skilled labor and professional expertise, and the deployment of substantial resources in a situation of extreme economic and social duress. Afghan culture is steeped in poetry and stories upon which its cinema draws. There is a hunger to tell stories. This thesis melds evaluations of extra-textual contexts with explorations of the cinematic language and narrative tropes of recent Afghan films in order to understand how this cinema connects and communicates with an Afghan audience.


identifier: Neal, Rachael ORCID: https://orcid.org/0000-0002-1175-1235 <https://orcid.org/0000-0002-1175-1235>  (2019) What Are You Looking For? Psychometric and Experimental Investigations of Reassurance Seeking in Obsessive-Compulsive Disorder.  PhD thesis, Concordia University.

abstract: In obsessive-compulsive disorder, reassurance seeking (RS) is associated with negative consequences for individuals who seek reassurance and their significant others. Reassurance seeking can be difficult to identify and treat, in part due to a lack of comprehensive assessment tools that can efficiently detect RS sought either overtly (i.e., obvious questions) or covertly (i.e., subtle attempts that are not direct questions), related to general threats (e.g., risks associated with stoves, locks) or social/relational threats (e.g., risks associated with relationship stability). Additionally, while the most commonly employed psychological treatment for RS entails strict refusal/withdrawal of accommodation to RS, this intervention may be associated with low acceptability. Conversely, a novel intervention wherein partners provide support to encourage tolerating distress may effectively reduce RS while being more acceptable to those who would receive it. This program of research was designed to address these gaps regarding assessment of and intervention for problematic RS. Study 1 entailed the validation and psychometric analysis of a novel measure of RS, the Covert and Overt Reassurance Seeking Inventory (CORSI), which assesses general and social/relational threat-motivated RS sought covertly or overtly. Results from undergraduate validation (N = 1621) and clinical (collapsed N = 140) samples suggested that the CORSI has a five-factor structure, sound psychometric properties, and can effectively discriminate RS of those with and without mental disorders. Study 2 entailed an experimental manipulation of partners’ feedback to correspond with support provision or traditional accommodation reduction in response to undergraduate participants’ (N = 102) RS following a threat-inducing task. Overall, support provision was associated with significantly greater ratings of helpfulness and a trend towards less overall RS. In Study 3, undergraduate participants and familiar partners (N = 179) provided ratings of perceived treatment acceptability/endorsement and selected which intervention they would prefer by reading vignette descriptions of RS interventions based on traditional accommodation reduction or support provision. Results indicated that participants and their partners provided more favourable ratings of acceptability/endorsement for the support provision intervention and were significantly more likely to select it than strict accommodation reduction. The implications of these findings for research and clinical practices are discussed.


identifier: Ghasemi Bijan, Mahmud  (2019) Algorithms for In-situ Efficiency Determination of Induction Machines.  PhD thesis, Concordia University.

abstract:
Robust structure, high reliability and low maintenance costs allow induction motors to be widely-used in various industrial applications. In recent decades, due to the increased concerns on global warming, and the effort to enhance the efficiency of tools, equipment, and systems, efficiency of induction machines (IMs) has received a lot of attention. The rated efficiency of an IM can be found on the nameplate. However, it is affected by aging, ambient temperature, load, supplied voltage and other technical reasons. Furthermore, based on NEMA MG 1 standard, the actual efficiency of an IM may vary from the nameplate value. As a result, efficiency estimation of IMs is essential to evaluate the efficiency of the whole system and energy cost.
Applying available international standards to in-situ machines needs load decoupling and in some cases, the no-load/locked-rotor test is required. This is not allowed with in-situ machines. Therefore, having a non-intrusive method which is capable of estimating the efficiency of the machine by using only available data such as the input voltages, currents, active power and nameplate data is necessary.
This thesis investigates in-situ methods to determine the efficiency of IMs and three related subjects are addressed. First, an optimization based algorithm is proposed to determine the efficiency of the IM at different loads. This algorithm is proven to have minimum intrusiveness and only uses the data of one operating point of the machine. Assumptions and techniques to increase the accuracy of the algorithm are addressed. The proposed algorithm is then applied to two conditions. In the first condition, the required input data are recorded when the machine reaches its thermal stability and final temperature rise of the machine is used as an input. In the second condition, the required input data are recorded 30 minutes after start of the machine and then the machine final temperature rise is predicted. Two approaches are proposed to predict final temperature rise and are based on machine insulation class and temperature rise of the machine in the first 30 minutes of operation of the machine after start.
Moreover, a method is proposed to determine the range of IM equivalent circuit parameters and improve the probability of converging to the correct answer. The method is based on the nameplate data of the machine and empirical results provided by Hydro-Québec. The method is also improved by using the operating data of the machine. The proposed range determination is very helpful for in-situ applications where the output power of the machine is not available.
Second, two dimensional finite element analysis (FEA) is used to predict the efficiency of the IMs at different loads. Two methodologies are adopted. In the first methodology, the losses are calculated directly using FEA while in the second one, the equivalent circuit parameters are first estimated using FEA and then the efficiency at different loads are estimated using the equivalent circuit parameters. To improve the results, a simple formula based on the rated power of the machine is proposed to evaluate the friction and windage losses also known as the mechanical loss of the machine. The proposed formula is applicable for 4-pole 60 Hz IMs and was achieved after study of more than 100 IMs of this type.
Third, the effects of the adjustable-speed drives on the losses and efficiency of the IMs are addressed. The direct torque control and scalar control schemes implemented by an industrial drive are employed to control two types of IMs. Two IMs designed for direct-fed application and two other IMs designed for PWM applications are studied while method B of IEEE Std-112 is applied to segregate the losses. Variations of different losses at drive-fed and direct-fed conditions are compared and results are discussed.


identifier: de Carné de Carnavalet, Xavier ORCID: https://orcid.org/0000-0003-2664-3963 <https://orcid.org/0000-0003-2664-3963>  (2019) Last-Mile TLS Interception: Analysis and Observation of the Non-Public HTTPS Ecosystem.  PhD thesis, Concordia University.

abstract: Transport Layer Security (TLS) is one of the most widely deployed cryptographic protocols on the Internet that provides confidentiality, integrity, and a certain degree of authenticity of the communications between clients and servers. Following Snowden's revelations on US surveillance programs, the adoption of TLS has steadily increased. However, encrypted traffic prevents legitimate inspection. Therefore, security solutions such as personal antiviruses and enterprise firewalls may intercept encrypted connections in search for malicious or unauthorized content. Therefore, the end-to-end property of TLS is broken by these TLS proxies (a.k.a. middleboxes) for arguably laudable reasons; yet, may pose a security risk. While TLS clients and servers have been analyzed to some extent, such proxies have remained unexplored until recently. We propose a framework for analyzing client-end TLS proxies, and apply it to 14 consumer antivirus and parental control applications as they break end-to-end TLS connections. Overall, the security of TLS connections was systematically worsened compared to the guarantees provided by modern browsers. Next, we aim at exploring the non-public HTTPS ecosystem, composed of locally-trusted proxy-issued certificates, from the user's perspective and from several countries in residential and enterprise settings. We focus our analysis on the long tail of interception events. We characterize the customers of network appliances, ranging from small/medium businesses and institutes to hospitals, hotels, resorts, insurance companies, and government agencies. We also discover regional cases of traffic interception malware/adware that mostly rely on the same Software Development Kit (i.e., NetFilter). Our scanning and analysis techniques allow us to identify more middleboxes and intercepting apps than previously found from privileged server vantages looking at billions of connections. We further perform a longitudinal study over six years of the evolution of a prominent traffic-intercepting adware found in our dataset: Wajam. We expose the TLS interception techniques it has used and the weaknesses it has introduced on hundreds of millions of user devices. This study also (re)opens the neglected problem of privacy-invasive adware, by showing how adware evolves sometimes stronger than even advanced malware and poses significant detection and reverse-engineering challenges. Overall, whether beneficial or not, TLS interception often has detrimental impacts on security without the end-user being alerted.


identifier: Plakhova, Olga  (2019) Understanding and Integrating Sustainability Into Strategy: A Case Study of a Transnational Automobile Corporation.  Masters thesis, Concordia University.

abstract:
Scientific research demonstrates that humanity is steadily bringing Earth to the limits of its planetary boundaries. Businesses, as powerful economic and social agents, have increasingly undertaken environmental strategies into their activities. Yet, even while firms increase their statements around sustainability, the concepts behind their actions – sustainable development, resilience, environmentalism, corporate social responsibility, and others - have not always been clear. These concepts have been changing over time since the 1980s, and even today there is no general agreement on their meaning neither among the scientists nor among the business practitioners. Moreover, even within a single firm, these terms may not be understood and interpreted the same way throughout an organization.

This problem brings to the main research question of this study which is to analyze how sustainability is understood, interpreted and integrated into a strategy of TNCs. I use a single case study to explore it on an example of a transnational corporation (TNC) in the automotive industry. In particular, I explore the external perspective of the firm through official public documents (annual reports, press releases) and internal perspective through interviews with managers within the TNC based in a European country. In this research, I find a gap between public documents and interviews; a gap between managers’ understanding of the importance of sustainability societally and their integration of meaningful sustainability-oriented actions into their day-to-day actions in the company; a gap between the purported value of sustainability as part of the firm’s strategy and its implementation.


identifier: Shahriar, Md. Istiaque  (2019) Modeling and Performance Analysis of Peer-to-Peer Live Streaming Systems.  PhD thesis, Concordia University.

abstract:
In recent years, Internet has witnessed a rapid growth in P2P (peer-to-peer) applications, especially, in the live streaming domain. There have been several deployments of largescale industrial level P2P live video systems, e.g., CoolStream, PPLive, Sopcast. Several contemporary measurement studies have verified that thousands of users can simultaneously participate in these systems. Almost all live P2P video systems offer multiple channels (e.g., PPLive can host over 100 channels). It is expected that in near future, live streaming systems with hundreds of user-generated channels will likely have thousands of live channels in total. With such a large number of streaming channels and huge number of participants, there are still some challenging issues needed to be addressed for an efficient P2P live streaming system. This PhD thesis is organized around three such problems related to the P2P live streaming systems.
In the first research problem, our focus is on the Dedicated Channels used by a Small numbered Viewers (can be termed as DCSV channels for short) in a multi-channel live streaming system. Usually, these are user generated channels and they suffer adversely from poor channel performance, mainly, due to having a small number of participants. As a result, when a viewer of such a channel explicitly requests for a block of streaming content (commonly referred as a chunk), the probability that the chunk will be available among the existing viewers is less than it would be if the number of viewers was higher in that channel (e.g., viewers in a popular channel). We have proposed HnH (short for Hand-in-Hand), a novel scheme of cross-channel resource sharing, in order to solve the performance problem of DCSV channels due to their small number of viewers. We next develop a discrete-time stochastic model in order to analyze its efficiency.
In the second research problem, we focus on the Free riders who only want to download and watch the streaming content from their neighboring peers but are unwilling to upload any content to their neighbors. The presence of free riders impose obstacle to the stability of any live streaming system because of consuming bandwidth from the system without significant contribution. We have investigated the performance of a Live streaming system with and without the presence of a free riders. First, we develop a discrete-time stochastic model and then compare the probability of continuous playback without any free rider and with certain amount of free riders. Next, we introduce a simple incentive mechanism and modify our stochastic model in order to accommodate the incentive mechanism. Then we compare the result of probability of continuous playback with and without having an incentive mechanism. Our work shows that presence of an incentive mechanism improves the overall system performance.
In the third research problem, we focus on less motivated peers who are not interested to upload streaming contents to their neighbors if those contents are not from the channels they are watching. The context of this work is related to our first research problem where we have proposed the HnH scheme and for simplicity have considered that all the peers from all participating DCSV channels are motivated to cooperate. However, in practice, some of them may behave selfish and become less motivated to help peers from other channels. In this work, we investigate the performance of a HnH scheme based Live streaming system with and without the presence of less motivated peers. First, we develop a discrete-time stochastic model and then compare the probability of continuous playback without any selfish peer and with certain amount of selfish peers. Next, we introduce a simple incentive mechanism and modify our stochastic model accordingly. Finally, we compare the result of probability of continuous playback with and without incentive mechanism. Our work shows that presence of an incentive mechanism improves the over all system performance due to the fact that less motivated peers are motivated to cooperate more by the improved performance.


identifier: Dittimi, T.V ORCID: https://orcid.org/0000-0002-0342-236X <https://orcid.org/0000-0002-0342-236X>  (2019) Banknote Authentication and Medical Image Diagnosis Using Feature Descriptors and Deep Learning Methods.  PhD thesis, Concordia University.

abstract: Banknote recognition and medical image analysis have been the foci of image processing and pattern recognition research. As counterfeiters have taken advantage of the innovation in print media technologies for reproducing fake monies, hence the need to design systems which can reassure and protect citizens of the authenticity of banknotes in circulation. Similarly, many physicians must interpret medical images. But image analysis by humans is susceptible to error due to wide variations across interpreters, lethargy, and human subjectivity. Computer-aided diagnosis is vital to improvements in medical analysis, as they facilitate the identification of findings that need treatment and assist the expert’s workflow. Thus, this thesis is organized around three such problems related to Banknote Authentication and Medical Image Diagnosis. In our first research problem, we proposed a new banknote recognition approach that classifies the principal components of extracted HOG features. We further experimented on computing HOG descriptors from cells created from image patch vertices of SURF points and designed a feature reduction approach based on a high correlation and low variance filter. In our second research problem, we developed a mobile app for banknote identification and counterfeit detection using the Unity 3D software and evaluated its performance based on a Cascaded Ensemble approach. The algorithm was then extended to a client-server architecture using SIFT and SURF features reduced by Bag of Words and high correlation-based HOG vectors. In our third research problem, experiments were conducted on a pre-trained mobile app for medical image diagnosis using three convolutional layers with an Ensemble Classifier comprising PCA and bagging of five base learners. Also, we implemented a Bidirectional Generative Adversarial Network to mitigate the effect of the Binary Cross Entropy loss based on a Deep Convolutional Generative Adversarial Network as the generator and encoder with Capsule Network as the discriminator while experimenting on images with random composition and translation inferences. Lastly, we proposed a variant of the Single Image Super-resolution for medical analysis by redesigning the Super Resolution Generative Adversarial Network to increase the Peak Signal to Noise Ratio during image reconstruction by incorporating a loss function based on the mean square error of pixel space and Super Resolution Convolutional Neural Network layers.


identifier: Mathin Henry, Kamal Maanicshah ORCID: https://orcid.org/0000-0001-6914-9610 <https://orcid.org/0000-0001-6914-9610>  (2019) A Study on Variational Component Splitting approach for Mixture Models.  Masters thesis, Concordia University.

abstract:
Increase in use of mobile devices and the introduction of cloud-based services have resulted in the generation of enormous amount of data every day. This calls for the need to group these data appropriately into proper categories. Various clustering techniques have been introduced over the years to learn the patterns in data that might better facilitate the classification process. Finite mixture model is one of the crucial methods used for this task. The basic idea of mixture models is to fit the data at hand to an appropriate distribution. The design of mixture models hence involves finding the appropriate parameters of the distribution and estimating the number of clusters in the data. We use a variational component splitting framework to do this which could simultaneously
learn the parameters of the model and estimate the number of components in the model. The variational algorithm helps to overcome the computational complexity of purely Bayesian approaches and the over fitting problems experienced with Maximum Likelihood approaches guaranteeing convergence. The choice of distribution remains the core concern of mixture models in recent research. The efficiency of Dirichlet family of distributions for this purpose has been proved in latest studies especially for non-Gaussian data. This led us to study the impact of variational component splitting approach on mixture models based on several distributions. Hence, our contribution is the application of variational component splitting approach to design finite mixture models based on inverted Dirichlet, generalized inverted Dirichlet and inverted Beta-Liouville distributions. In addition, we also incorporate a simultaneous feature selection approach for generalized inverted Dirichlet mixture model along with component splitting as another experimental contribution. We evaluate the performance of our models with various real-life applications such as object, scene, texture, speech and video categorization.


identifier: Zeng, Yi  (2019) An Exploratory Study on the Characteristics of Logging Practices in Mobile Apps: A Case Study on F-Droid.  Masters thesis, Concordia University.

abstract: Logging is a common practice in software engineering. Prior research has investigated the characteristics of logging practices in system software (e.g., web servers or databases) as well as desktop applications. However, despite the popularity of mobile apps, little is known about their logging practices. In this thesis, we sought to study logging practices in mobile apps. In particular, we conduct a case study on 1,444 open source Android apps in the F-Droid repository. Through a quantitative study, we find that although mobile app logging is less pervasive than server and desktop applications, logging is leveraged in almost all studied apps. However, we find that there exist considerable differences between the logging practices of mobile apps and the logging practices in server and desktop applications observed by prior studies. In order to further understand such differences, we conduct a firehouse email interview and a qualitative annotation on the rationale of using logs in mobile app development. By comparing the logging level of each logging statement with developers' rationale of using the logs, we find that all too often (35.4%), the chosen logging level and the rationale are inconsistent. Such inconsistency may prevent the useful runtime information to be recorded or may generate unnecessary logs that may cause performance overhead. Finally, to understand the magnitude of such performance overhead, we conduct a performance evaluation between generating all the logs and not generating any logs in eight mobile apps. In general, we observe a statistically significant performance overhead based on various performance metrics (response time, CPU and battery consumption). In addition, we find that if the performance overhead of logging is significantly observed in an app, disabling the unnecessary logs indeed provides a statistically significant performance improvement. Our results show the need for a systematic guidance and automated tool support to assist in mobile logging practices.


identifier: Li, Zhenhao  (2019) Characterizing and Detecting Duplicate Logging Code Smells.  Masters thesis, Concordia University.

abstract: Developers rely on software logs for a wide variety of tasks, such as debugging, testing, program comprehension, verification, and performance analysis. Despite the importance of logs, prior studies show that there is no industrial standard on how to write logging statements. Recent research on logs often only considers the appropriateness of a log as an individual item (e.g., one single logging statement); while logs are typically analyzed in tandem. In this thesis, we focus on studying duplicate logging statements, which are logging statements that have the same static text message. Such duplications in the text message are potential indications of logging code smells, which may affect developers’ understanding of the dynamic view of the system. We manually studied over 3K duplicate logging statements and their surrounding code in four large-scale open source systems: Hadoop, CloudStack, ElasticSearch, and Cassandra. We uncovered five patterns of duplicate logging code smells. For each instance of the code smell, we further manually identify the problematic (i.e., require fixes) and justifiable (i.e., do not require fixes) cases. Then, we contact developers in order to verify our manual study result. We integrated our manual study result and developers’ feedback into our automated static analysis tool, DLFinder, which automatically detects problematic duplicate logging code smells. We evaluated DLFinder on the four manually studied systems and four additional systems: Kafka, Flink, Camel and Wicket. In total, combining the results of DLFinder and our manual analysis, we reported 91 problematic code smell instances to developers and all of them have been fixed. This thesis provides an initial step on creating a logging guideline for developers to improve the quality of logging code. DLFinder is also able to detect duplicate logging code smells with high precision and recall.


identifier: Sekyere Asare, Irene  (2019) Yield Curve Modelling: A Comparison of Principal Components Analysis and the Discrete-Time Vasicek Model.  Masters thesis, Concordia University.

abstract: The term structure of interest rates is relevant to economists as it reflects the information available to the market about the time value of money in the future. Affine term structure models such as short rate models have been used in interest rate modelling over the past years to determine the mechanisms driving the term structure. Machine learning approaches are explored in this thesis and compared to the traditional econometric approach, specifically the Vasicek model. Multifactor Vasicek models are considered as the one factor model is found not adequate to characterize the term structure of interest rates.  Since the short rates are not observable the Kalman filter approach is used in estimating the parameters of the Vasicek model.  This thesis utilizes the Canadian zero-coupon bond price data in the implementation of both methods and it is observed from both methods that increasing the number of factors to three increases the ability to capture the curvature of the yield curve. The first factor is identified to be responsible for the level of the yield curve, the second factor the slope and third factor the curvature of the yield curve. This is consistent with results obtained from previous work on term structure models. The results from this work indicates that the machine learning technique, specifically the first three principal components of the Principal Component Analysis (PCA), outperforms the Vasicek model in fitting the yield curve.


identifier: Bidare Kantharajappa, Shreyamsha Kumar ORCID: https://orcid.org/0000-0002-3781-0635 <https://orcid.org/0000-0002-3781-0635>  (2019) Visual Tracking Algorithms using Different Object Representation Schemes.  PhD thesis, Concordia University.

abstract:
Visual tracking, being one of the fundamental, most important and challenging areas in computer vision, has attracted much attention in the research community during the past decade due to its broad range of real-life applications. Even after three decades of research, it still remains a challenging problem in view of the complexities involved in the target searching due to intrinsic and extrinsic appearance variations of the object. The existing trackers fail to track the object when there are considerable amount of object appearance variations and when the object undergoes severe occlusion, scale change, out-of-plane rotation, motion blur, fast motion, in-plane rotation, out-of-view and illumination variation either individually or simultaneously. In order to have a reliable and improved tracking performance, the appearance variations should be handled carefully such that the appearance model should adapt to the intrinsic appearance variations and be robust enough for extrinsic appearance variations. The objective of this thesis is to develop visual object tracking algorithms by addressing the deficiencies of the existing algorithms to enhance the tracking performance by investigating the use of different object representation schemes to model the object appearance and then devising mechanisms to update the observation models.

A tracking algorithm based on the global appearance model using robust coding and its collaboration with a local model is proposed. The global PCA subspace is used to model the global appearance of the object, and the optimum PCA basis coefficients and the global weight matrix are estimated by developing an iteratively reweighted robust coding (IRRC) technique. This global model is collaborated with the local model to exploit their individual merits. Global and local robust coding distances are introduced to find the candidate sample having similar appearance as that of the reconstructed sample from the subspace, and these distances are used to define the observation likelihood. A robust occlusion map generation scheme and a mechanism to update both the global and local observation models are developed. Quantitative and qualitative performance evaluations on OTB-50 and VOT2016, two popular benchmark datasets, demonstrate that the proposed algorithm with histogram of oriented gradient (HOG) features generally performs better than the state-of-the-art methods considered do. In spite of its good performance, there is a need to improve the tracking performance in some of the challenging attributes of OTB-50 and VOT2016.

A second tracking algorithm is developed to provide an improved performance in situations for the above mentioned challenging attributes. The algorithms is designed based on a structural local 2DDCT sparse appearance model and an occlusion handling mechanism. In a structural local 2DDCT sparse appearance model, the energy compaction property of the transform is exploited to reduce the size of the dictionary as well as that of the candidate samples in the object representation so that the computational cost of the l_1-minimization used could be reduced. This strategy is in contrast to the existing models that use raw pixels. A holistic image reconstruction procedure is presented from the overlapped local patches that are obtained from the dictionary and the sparse codes, and then the reconstructed holistic image is used for robust occlusion detection and occlusion map generation. The occlusion map thus obtained is used for developing a novel observation model update mechanism to avoid the model degradation. A patch occlusion ratio is employed in the calculation of the confidence score to improve the tracking performance. Quantitative and qualitative performance evaluations on the two above mentioned benchmark datasets demonstrate that this second proposed tracking algorithm generally performs better than several state-of-the-art methods and the first proposed tracking method do. Despite the improved performance of this second proposed tracking algorithm, there are still some challenging attributes of OTB-50 and of VOT2016 for which the performance needs to be improved.

Finally, a third tracking algorithm is proposed by developing a scheme for collaboration between the discriminative and generative appearance models. The discriminative model is explored to estimate the position of the target and a new generative model is used to find the remaining affine parameters of the target. In the generative model, robust coding is extended to two dimensions and employed in the bilateral two dimensional PCA (2DPCA) reconstruction procedure to handle the non-Gaussian or non-Laplacian residuals by developing an IRRC technique. A 2D robust coding distance is introduced to differentiate the candidate sample from the one reconstructed from the subspace and used to compute the observation likelihood in the generative model. A method of generating a robust occlusion map from the weights obtained during the IRRC technique and a novel update mechanism of the observation model for both the kernelized correlation filters and the bilateral 2DPCA subspace are developed. Quantitative and qualitative performance evaluations on the two datasets demonstrate that this algorithm with HOG features generally outperforms the state-of-the-art methods and the other two proposed algorithms for most of the challenging attributes.


identifier: Edache, Iyoma Yvonne  (2019) Weight Bias and Support of Public Health Policies.  Masters thesis, Concordia University.

abstract:
Background. Public explicit weight bias attitudes have yet to be assessed in a Canadian representative sample. It is unknown if explicit weight bias negatively influences Canadian public perceptions of public health policies aimed at addressing obesity.
Objectives. To examine: (1) explicit weight bias, (2) public support of the Canadian Federal Government’s public health policy recommendations to address obesity, and (3) the association between explicit weight bias and policy support in Canada.
Methods. Canadian adults (N=1003; 51% female; BMI=27.37.0 kg/m2) completed an online survey in October 2018. Weight bias was measured with the Anti-Fat Attitudes Questionnaire in three subscales: Willpower, Fear of fat, and Dislike. Support of policy recommendations was measured on 4-point Likert scales. Logistic regressions (support vs oppose) were conducted after adjusting for age, race, gender and income.
Results. Support of policy recommendations ranged from 53% to 90%. Willpower was associated with support of 10 policies (e.g. changing infrastructure to encourage physical activity, OR=1.28, CI=1.14-1.43, P<0.01). Dislike was associated with support of three policies (e.g. taxation of sugar and artificially sweetened beverages, OR=1.19, CI=1.08-1.31, P<0.01). However, Fear of fat was negatively associated with support of two policies (e.g. mandating the use of front-of-package nutrition labelling, OR=0.82, CI=0.73-0.94, P<0.01)
Conclusions. Weight bias is associated with Canadian support of public health policies aimed at addressing obesity. Future studies should examine the influence of weight bias reduction interventions on policy support.


identifier: Chung, Michael  (2019) Biophysical and biochemical characterization of human tRNA nucleotidyltransferase variants.  Masters thesis, Concordia University.

abstract:
The enzyme ATP(CTP):tRNA nucleotidyltransferase (tRNA-NT) is required for tRNA maturation and repair.  This enzyme adds to tRNAs the universally conserved 3’-cytidine-cytidine-adenosine (CCA) sequence required for aminoacylation.  Given the essential role of this enzyme in protein synthesis, human disease phenotypes have been linked to mutations in the gene encoding this protein (Aksentijevich et al. 2014; Chakraborty et al. 2014; Sasarman et al. 2015; DeLuca et al. 2016; Hull et al. 2016; Wedatilake et al. 2016; Frans et al. 2017; Lougaris et al. 2018; Giannelou et al. 2018; Bader-Meunier et al. 2018; Gorodetsky et al. 2018; Kumaki et al. 2019; Abdulhadi et al. 2019).  The variant proteins characterized to date have shown reduced thermostability relative to the native enzyme (Leibovitch et al. 2018, 2019), suggesting that reduced stability of tRNA-NT may lead to the phenotypes observed.

Here, we looked at additional variant proteins to see if these disease-linked variants also show reduced thermostability.  The variant proteins characterized here were E43Δ which had a glutamate residue deleted near the N-terminus of the protein, R99W which contained an arginine-to-tryptophan substitution near the active site of the enzyme, and A[8] with a frame shift that truncated the protein by nine amino acids and altered the new C-terminal eight amino acids.

Interestingly, biophysical and biochemical characterization of these variants showed no major decrease in thermostability relative to the native enzyme.  However, all three variants showed a reduced ability to incorporate AMP into a specific tRNA template in vitro.  This suggests that, in addition to reduced thermostability, effects in AMP incorporation may also be linked to a disease phenotype.  Interestingly, the E43Δ, R99W and A[8] variants all affected different aspects of AMP incorporation, reflecting their different locations in the protein and suggesting that AMP incorporation may be mediated by different domains and substructures spanning the entire enzyme and not confined simply to the active site.


identifier: Yan, Chian  (2019) Numerical Investigation of Chemical Reactivity Effects on the Formation of Gaseous Oblique Detonation Waves.  Masters thesis, Concordia University.

abstract: The concept of using oblique detonation waves for high efficiency propulsion systems have recently generated great interest in the development of air-breathing hypersonic aircraft due to their potential increased thermal efficiency through detonative combustion. However, for the proper design of an Oblique Detonation Wave Engine (ODWE), it is critical to predict the necessary conditions and understand the formation mechanism of oblique detonation waves. In this study, numerical simulations using a Graphics Processing Unit (GPU)-based solver are performed to investigate oblique detonations induced by a two-dimensional, semi-infinite wedge using the reactive Euler equations coupled with one-step Arrhenius or two-step induction-reaction kinetics. The novelty of this work lies in the analysis of chemical reaction sensitivity on the two types of oblique detonation formation, namely, the abrupt onset with a multi-wave point and a smooth transition with a curved shock. Scenarios with various inflow Mach number regimes M0 and wedge angles θ are considered. The conditions for these two formation types are described quantitatively by the obtained boundary curves in M0-Ea and M0-kR spaces. At a low M0, the critical conditions for the transition are independent of the wedge angle. At a high flow Mach number regime with M0 above approximately 9.0, the boundary curves for the three wedge angles deviate substantially from each other. The overdrive effect induced by the wedge becomes the dominant factor on the transition type. For large Ea the flow in the vicinity of the initiation region and subsequent ODW surface also exhibit more complex features.


identifier: Patronidis, Filareti  (2019) Impact of a 4-Week Home-Based Exercise Program on the Functional Capacity of Advanced Cancer Patients: A feasibility pilot study.  Masters thesis, Concordia University.

abstract: Research has demonstrated that a physically active lifestyle can counter some of the cardio-respiratory and musculoskeletal losses associated with cancer. Still, exercise guidelines for advanced cancer patients are unspecific, and exercise prescription can be complicated, due to a multitude of factors that may influence the degree of physiological and functional decline from patient to patient. In the present study, twenty-one supportive care patients with stage III or IV cancers were prescribed a 4-week exercise intervention, in conjunction to standard care. The program included 12 unsupervised resistance training and walking sessions, and participants were assessed pre and post exercise intervention. The primary aim of this study is to examine pre-post exercise program changes in function, strength, body composition, energy expenditure, and health-related quality of life (HRQOL). Functional tests, including the 6-minute-walk-test (6MWT) were used to assess performance. Body composition was assessed using dual-energy x-ray absorptiometry (DXA) and accelerometers were used to assess energy expenditure and step-count before and after exercise intervention. The Edmonton Symptom Assessment System (ESAS) and the abridged Patient-Generated Subjective Global Assessment (aPG-SGA) questionnaires were used to examine symptom profile and health related quality of life (HRQOL). We hypothesized improvements in functional scores and increased daily energy expenditures post-exercise as compared to baseline. The secondary aim of the study is to assess its feasibility in the given population. Feasibility was evaluated based on: i) recruitment rate, ii) retention rates, iii) test performance, iv) exercise program tolerability, and v) adherence to prescription. Paired t-tests were used to assess pre-post intervention differences. Findings indicate statistical and clinical significant improvement in 6MWT distance. Pre-post reports of HRQOL were maintained with significant decrease in pain. Upper and lower body strength significantly improved over the 4 weeks. Daily energy expenditure and daily step-count also showed meaningful increase post-exercise intervention. Our findings suggest that, the proposed exercise prescription encourages a more active lifestyle and can improve functionality of supportive care cancer patients.


identifier: Badasu, Mawuena ORCID: https://orcid.org/0000-0002-2396-4852 <https://orcid.org/0000-0002-2396-4852>  (2019) “It was a bit my fault and a bit his fault": Mothers' and Early School-aged Children’s Blame Attributions in Conversations about Peer Conflicts.  Masters thesis, Concordia University.

abstract: In a sample of 36 dyads, this study investigated mothers’ and their 6-7-year-old children’s blaming strategies when engaged in conversations about the children’s peer conflicts. Each dyad discussed two conflicts in which the child was hurt, one to which they felt they contributed (shared fault) and the other in which they felt they did not contribute to the conflict (no fault). We specifically examined: (1) how conversations about the two events differed in terms of maximizing and mitigating blame attributions across three contexts (the peer’s harm against the child, child’s harm to the peer, and the child’s self-protection from harm) (2) variations between mothers and children’s maximizing and mitigating blame strategies (3) the specific dimensions that mothers and children considered in making blame attributions. Results revealed that families maximized responsibility more in the no fault conversations in the context of harm to the child and self-protection from harm, whereas they maximized blame concerning the child’s harm to his/her peer more in the shared fault conversations. Comparing mothers and children, findings indicated that mothers maximized blame more in self-protection contexts, whereas children maximized blame for the peers’ harm to child and mitigated responsibility across all contexts. Regarding dimensions of blame attribution, avoidability and consequences of harm were used most often by families. Mothers referenced avoidability and act evaluations most frequently whereas children more often discussed presence of harmful acts and subsequent responses to one’s own harm. Findings suggest that maternal socialization of blame is context-sensitive as mother-child dyads are listening to and largely agreeing with each other. Mothers’ emphasis on self-protection raises questions about parental concerns for children’s responsibility and agency in the context of victimization. Implications for children’s moral development are discussed.


identifier: Luo, Jianing  (2019) Development of Advanced Controller to Achieve Complete Peak Shifting in Light-Weight Residential Buildings Located in Cold Climate.  Masters thesis, Concordia University.

abstract:
In the cold northern climate of Canada, building energy consumption for space heating during the winter have caused huge stress on electrical grids, especially during the peak hours. Shifting or shaving the peak demand can avoid additional capital investment required to meet extra peak demand for the electrical suppliers. Consequently, in the recent years, several utility companies adopted time-based rates to encourage the customers to shift their consumption from high demand hours to those with lower demand. In this regard, the two most commonly used time-based rates are time-of-use tariffs and critical peak pricing. Achieving peak shifting can reduce the heating cost under time-based rates for consumers. Overall, peak shaving is benefit not only for the electrical suppliers but also for the consumers.
Most Canadian residential houses are equipped with a concrete slab in their basement primarily for structural integrity. Such high thermal mass concrete slab can be exploited for heat storage to shift the peak power consumption. To take benefit of the concrete slabs in the basement, in previous research works, the self-learning control system and the heat extraction system were proposed to achieve peak shifting in the basement and in the other floors of the buildings, respectively. Despite several advantages, the major limitation of these studies is that the developed self-learning control system focused only on peak shifting in the basement, while the heat extraction system concept was investigated separately from the self-learning control system.
Accordingly, this study focused on developing an advanced controller, which can efficiently operate both electrically heated floor and heat extraction system with the objective of achieving the peak shifting, heating cost savings and guaranteeing the thermal comfort in the whole building. As a preliminary work of this study, the peak shifting ability and heating cost savings potential of the self-learning control system operated electrically heated floor under two electrical tariffs (i.e. time-of-use tariffs and critical peak pricing) was analyzed using a validated TRNSYS-MATLAB model. Later, the advanced controller was developed for extending the peak shifting from the floor with high thermal mass to that without high thermal mass by the electrically heated floors integrated with the heat extraction system. In this regard, the developed TRNSYS-MATLAB model was integrated with the heat extraction system. Consequently, the peak shifting ability, heating cost savings of the advanced controller was compared with the other commonly used peak shifting control strategies (i.e. constant set point control and rule-based control) and the respective results are presented. At last, a parametric study using Taguchi method was performed to explore the effective parameters that significantly influence the performance of electrically heated floor, heat extraction system in terms of peak shifting ability, thermal comfort and capital cost. For this purpose, three levels were considered for five factors (A) concrete slab thickness, (B) insulation thickness, (C) fan flow rate, (D) indoor air temperature upper limit and (E) floor surface temperature upper limit. Based on the results of the parametric study, overall recommendation to design the optimal electrically heated floors and heat extraction system was provided.
Regarding the results, the peak shifting, thermal comfort and heating cost saving are presented for two tariffs (time-of-use tariffs and critical peak pricing) considering the floor with concrete. The simulation results showed that the peak shifting can be achieved at 99.7% in critical peak pricing and 97.6% in time-of-use tariffs, respectively. On the other hand, to extend the peak shifting in the whole building, self-learning control integrated with a fan (heat extraction system) can improve the peak shifting in basement (up to 97%) and second floor (up to 88%). The cost saving can also increase around 35%, which can be proven financially attractive to both supplier and owner. At last, through parametric study, the optimal condition for efficient design and operation of electrically heated floor system and heat extraction system was found to be concrete slab thickness of 152.4 mm, an insulation thickness of 101.6 mm, a fan flow rate of 400 CFM, air indoor upper limit of 24.5 °C and floor surface temperature upper limit of 28 °C


identifier: Rosenstein, Brent  (2019) Short- and Long-Term Changes in Cognitive Function After Exercise-Based Rehabilitation in People with COPD.  Masters thesis, Concordia University.

abstract:
Objective: To compare the 12-week effects of continuous high-intensity training (CTHI), continuous training at the ventilatory threshold (CTVT) and high-intensity interval training (HIIT) on cognition, and the 1-year maintenance of these effects in people with COPD.

Methods: Participants were randomized to CTHI, CTVT, or HIIT and underwent 12 weeks of three times weekly training on cycle ergometers. The intensity phase included 25 minutes of pedaling at 80% of peak wattage (Wpeak) for CTHI. For CTVT, the intensity was set at the ventilatory threshold, while HIIT consisted of 30-second intervals at 100% of Wpeak alternated with unloaded pedaling. Session duration for CTVT and HIIT was calculated to ensure comparable total work as for CTHI. Assessments were made at baseline (week 0), program completion (week 12) and 1 year after baseline (year 1). Cognition was assessed with a neuropsychological testing battery. Global cognitive function was assessed using the Montreal Cognitive Assessment (MoCA).

Results: Thirty-six participants (64% women, mean age: 67.5±9 years) with moderate COPD were randomized. The 12-week effects of exercise training on cognition were small or very small, except for visuospatial abilities, which detected larger effects especially in participants with mild cognitive impairment at baseline. There was considerable heterogeneity between intervention groups. CTHI was the only group with medium-to-large effects in each cognitive domain assessed. At year 1, gains and losses in cognition were seen in all groups.

Conclusion: In COPD, 12 weeks of training led to small changes in cognition, with notable heterogeneity between exercise protocols and across cognitive domains.


identifier: Pan, Weixian  (2019) China Southern: Digital Environments as Geopolitical Contact Zones.  PhD thesis, Concordia University.

abstract: This dissertation examines the role of digital media in shaping the geopolitics and materiality of environments in China over the first two decades of the twenty-first century. I look at digital discourses (“smartness,” “connectivity,” “data transparency”), media practices (film/video, satellite images, data capture), and infrastructures (surveillance, telecommunication) and argue that environments, such as land, sea, and air, are increasingly transformed into political territories, and engineered as part of the new technologies of social governance in the digital era. More specifically, this dissertation moves from urban smart infrastructures in Southern China (chapter one), to contested mediations of the disputed South China Sea (chapter two), and finally, to the circulation of air pollution data and imaginaries across the global South (chapter three). With ethnographic research in addition to visual and discursive analysis, my work employs a multi-scalar approach—sub-national, regional, global—to explore both the institutional and popular actors that shape these eco-digital formations. Focusing on the South as both a geographical and political concept, this orientation challenges the Northern-centered vocabularies and framing to global film and media studies. Meanwhile, China Southern reinstates the transnational momentum of the Southern question (Casarino 2010), especially situated at the juncture between neoliberal experiments since the 1990s and the rise of the “Chinese Dream” in the 2000s as a cultural discourse. In doing so, this research contributes to the broader discussion on global governance, and conceptualizes the often obscured theoretical and material entanglement of media and environments in Asia.


identifier: Kazi, Ananyo  (2019) p-adic Modular Forms.  Masters thesis, University of Milan, Concordia University.

title: p-adic Modular Forms

abstract: We study the approach of N.M. Katz to define p-adic modular forms, first as sections of tensor powers of the sheaf of invariant differentials on the formal ordinary locus and then as functions on the Katz modula satisfying certain transformation properties under the action of a Galois group, depending on the weight. Next we study the Igusa tower and the big Igusa tower and describe an action of the multiplicative formal group on the Igusa tower which restricts to an action on the Katz tower. We show, that one gets back the [theta]-operator of Serre by differentiating this action.


identifier: Ng, Edwin  (2019) Decomposition of risk based on the Martingale Representation Theorem for annuity and insurance portfolios.  Masters thesis, Concordia University.

abstract: Numerous methods have been proposed throughout the literature for decomposing liabilities into risk factors. Such analysis is of great importance because it allows for explaining the impact of each source of risk in relation to the total risk, and thus it allows actuaries to have a certain degree of control over uncertainties. In an insurance context, such sources usually consist of the mortality risk, represented in this paper by the systematic and by the unsystematic mortality risk, and of the investment risk. The objective of this thesis is to consider the Martingale Representation Theorem (MRT) introduced by Schilling et al., (2015) for such risk decomposition, because this method allows for a detailed analysis of the influence of each source of risk. The proposed dynamic models used in this thesis are the Lee-Carter model for the mortality rates and, the arbitrage-free Nelson-Siegel (AFNS) models for the interest rates. These models are necessary in providing accuracy by improving the overall predictive performance. Once, the risk decomposition has been achieved, quantifying the relative importance of each risk factor under different risk measurements is then proceeded. The numerical results are based on annuities and insurances portfolios. It is found that for extended coverage periods, investment risk represents most of the risk while for shorter terms, the unsystematic mortality risk takes larger importance. It is also found that the systematic mortality risk is almost negligible.


identifier: Couture, Sadie  (2019) Aural Intimacies: Gendered Constructions of Familiarity on The Mary Margaret McBride Program.  Masters thesis, Concordia University.

abstract:
In this project I theorize the work of Mary Margaret McBride who hosted a number of shows on American network radio from 1934-1954. On her genre-defying programs, McBride chatted in a casual and unscripted way with guests, fluidly discussing both their professional and personal lives. McBride’s relationship with her listeners was characterized by feelings of closeness, trust, loyalty and intimacy (Ware, 2005). I connect McBride’s relationship with her fans to radio history and theory, especially certain ‘media fantasies’ (Verma, 2012) of the early twentieth century in which radio was understood as a particularly important medium for fostering connection, community, and democracy (Loviglio, 2005; Marvin, 1988; Mosco, 2004; Peters, 1999).

I present findings from my archival research at the Library of Congress in Washington, DC. In my analysis, I follow Neil Verma (2012) and John Barnhurst and Kevin Nerone (2001), and focus on the form of McBride’s program. I investigate what her program sounds like, and how and why did it fostered such close personal connections between listeners, guests, and McBride. My research suggests a number of factors which may have contributed to the atmosphere of gendered familiarity evident in McBride’s work. I argue that McBride’s embrace of magazine format, innovative advertising techniques, use of pace and audioposition (Verma, 2012), combined with the fluidity and non-segmentation of her show, constructed an audio media context in which listeners felt connected to each other, to McBride, and to the products she promoted, constituting an emergent structure of feeling (Williams, 1977).


identifier: Sun, David Yuan-Jae ORCID: https://orcid.org/0000-0002-6002-3138 <https://orcid.org/0000-0002-6002-3138>  (2019) A study of the integration of semi-transparent phtovoltaics with sunscreen structures in a major transportation infrastructure tunnel.  Masters thesis, Concordia University.

abstract:
This thesis presents a study of the energy consumption of a major underwater road tunnel in Québec and the possible integration of photovoltaics, as well as other energy efficiency
measures. A novel application of semi-transparent photovoltaics (STPV) integrated with sunscreen structures (SS) installed at the portals of the tunnel is presented as a retrofit primarily for the tunnel lighting system, but with auxiliary benefits to other major systems and road safety conditions. A study on the operational power and energy use of the heating,
lighting, and ventilation systems was performed to estimate the potential energy and monetary savings of this application.

Lighting subsystems account for up to 50% of the energy consumption of a typical tunnel. Day-time lighting levels account for over two-thirds of the total system lighting power; their periodic nature creates daily peaks in the tunnel’s energy load profile.

The 1.3 km long Louis-Hippolyte-La Fontaine underwater road tunnel, located in Montréal, Québec is presented as a representative case study for cold climates. A model of the lightingsystem was developed using recorded data from a supervisory control and data acquisition (SCADA) system and calibrated using metered data provided by the electric utility. This model was used to evaluate the energy and power demands of the lighting system, in comparison
to estimates of other major systems that consume electricity in the tunnel.

Additionally, a daylighting model was created with the DIVA-for-Rhino daylighting plugin for the Rhinoceros and Grasshopper software using detailed construction plans. This
was used to evaluate the function of the semi-transparent photovoltaic sunscreen (STPV-SS) structure as a shading device to gradually reduce the contrast between the outdoor and indoor environments. Its primary goal is to reduce the lighting requirements necessary for the safe adaptation of the human visual system (HVS) of motorists entering the tunnel and reduce the black hole effect and glare from the sun during critical glare hours (CGH). Different STPV options with varying transparencies and visible light transmittances (VLT) were considered to determine the option most suitable for tunnels. Matrix-based STPVs achieve their degree of transparency by alternating between opaque PV material and transparent glass.
Intrinsically STPVs are process-induced materials such as thin-film or organic PVs whose transparency is an innate characteristic. Energy saving and energy production potential from the STPV system is greatest with matrix-based STPV options, however, safety conditions suffer greatly from poor visibility, resulting from poor uniformity of the transmitted daylight. The most balanced option was low VLT intrinsically STPV technology, which resulted in better daylight uniformity, and lower artificial lighting demands. Low VLT intrinsically
STPV options also have higher PV efficiencies than their high VLT counterparts. It also resulted in the highest reduction in equivalent veiling luminance (disability glare) for drivers
during CGH. Reductions in lighting system requirements over the tunnel length, including the threshold, transition and interior lighting zones of the tunnel were considered. Results
showed that the application of STPV-SS structures at entrances of the LHLF tunnel could reduce annual energy demands of the lighting system by between 10% to 18%, depending on
the VLT of the structure.


identifier: Rahman, Md. Hafizur  (2019) Absolutely Continuous Invariant Measures for Piecewise Convex Maps of Interval with Infinite Number of Branches.  Masters thesis, Concordia University.

abstract: The main result of this Master's thesis is the generalization of the existence of absolutely continuous invariant measure for piecewise convex maps of an interval from a case with the finite number of branches to one with infinitely many branches. We give a similar result for piecewise concave maps as well. We also provide examples of piecewise convex maps with a finite and infinite number of branches without ACIM.


identifier: Kelly-Turner, Kenneth  (2019) The fear of losing control in social anxiety: An experimental approach.  Masters thesis, Concordia University.

abstract: Social anxiety disorder is often conceptualized as arising from a variety of maladaptive cognitions (e.g., attentional bias towards internal sensations, negative beliefs about the self and a fear of negative evaluation). One cognitive domain that has received relatively little attention, despite endorsement from people struggling with social anxiety, is the belief that they may lose control over their speech/behaviour and/or their physical symptoms of anxiety. This parallels similar beliefs about losing control seen in other disorders (e.g., panic disorder, obsessive-compulsive disorder). The present study aimed to evaluate the causal role of beliefs about losing control on social anxiety symptoms in an analogue sample. Beliefs were manipulated using false feedback in a sample of undergraduate psychology students (N = 130) to induce either high or low levels of beliefs about losing control. Participants then engaged in a ‘getting to know you’ task with a confederate. Participants in the high beliefs about losing control (HLC) condition reported significantly greater anxiety just before meeting the confederate than those in the low loss of control (LLC) condition (t(128)=2.90, p=0.004, d=0.51). Further HLC participants reported significantly worse social performance than did those in the LLC condition during their social interaction with a confederate (F(1, 128)=4.19, p=0.04). Finally, the HLC condition was associated with greater perceived failure of control over behaviour during the social interaction than was the LLC condition (t(128)=2.93, p=0.004, d=0.51). Results suggest beliefs about losing control are relevant to the cognitive model of and perhaps treatments for social anxiety.


identifier: Dumais, Douglas  (2019) Making Up Lost Time: Fiction in Carol Sawyer’s The Natalie Brettschneider Archive and the Canadian Women Artists History Initiative.  Masters thesis, Concordia University.

abstract: This thesis examines Vancouver-based contemporary artist Carol Sawyer’s The Natalie Brettschneider Archive as well as the Concordia-based Canadian Women Artists History Initiative (CWAHI) through the lens of fiction, feminist theory, and counter-archival practices. Sawyer’s Archive is a series of documents that recount the biography of fictional Surrealist and Dada performance artist Natalie Brettschneider (1896-1986?). CWAHI is a Concordia-based documentation centre that maintains artist files, programming, and publication initiatives. This thesis argues that fiction is an effective tool to address historiographical erasures in women’s history. Though both projects emerge from the polarities of fictional art and historical documentation practices, CWAHI and the Archive are invested in the plausibilities for feminist interventions veiled within the unknowability of the past. Chapter one explores how the Archive renders sensible and actionable a cross-historical dialogue with historical women’s art, one that argues for an expanded notion of intertemporal feminist collaboration. Similarly, CWAHI’s collaborators craft frameworks that forge communities of participation that generate affective resonances between artists of the past and historians in the present. Chapter two complicates this collapse between historical and contemporary, arguing that Sawyer’s Archive and CWAHI sustain tensions at the heart of feminist scholarship between historical women artists and the historians who study them. Both projects recognize that the historian and their subjects of study are entangled across differing contexts. The result are two projects that speak to the variety of experiences across divides of fact and fiction, past and present, as well as life and death, divides that Sawyer’s project argues can be partially, but never fully, breached.


identifier: Szwimer, Erica  (2019) The Association Between Weight-Based Teasing from Peers and Family in Childhood and Depressive Symptoms in Childhood and Adulthood: A Systematic Review.  Masters thesis, Concordia University.

abstract: RECENT FINDINGS: Depressive symptoms may be a psychological correlate of weight-based teasing from peers and/or family. However, it is unclear whether the association of weight-based teasing with depressive symptoms differs by time (short-term vs. long-term), sex (males vs. females) or source (family vs. peers). PURPOSE: The purpose of this systematic review was to (1) examine whether the frequency of weight-based teasing differs according to sex and source and (2) examine whether the association of weight-based teasing with depressive symptoms varies according to time, sex and source. METHODS: On February 16th, 2018, a combination of keywords within three concepts: i) children and adults; ii) weight-based teasing source and: iii) mental health outcomes were searched in four databases (PubMed, PsychINFO, SCOPUS and Web of Science) for relevant articles. Cross-sectional and longitudinal original research articles were included, and studies were excluded if the relationship between weight-based teasing and depressive symptoms were not explicitly measured. RESULTS: The search yielded 3572 articles and nineteen studies were included in the final analysis. Experiences of weight-based teasing occurred more frequently among girls than boys. Peers were a more common source of weight-based teasing compared to family. Weight-based teasing was significantly associated with depressive symptoms in both the short and long-term. Weight-based teasing exhibited a greater association with depressive symptoms in girls vs. boys and when it came from multiple sources than from either source alone. SUMMARY: Weight-based teasing from peers and family is associated with depressive symptoms, and females are more psychologically vulnerable than males. Interventions are required to reduce weight-based teasing and its harmful psychological effects.


identifier: Alkhalaf, Ali  (2019) Design, Development, and Analysis of a Tactile Display Based on Composite Magnetorheological Elastomers.  Masters thesis, Concordia University.

abstract: In minimally invasive surgery, surgeons carry out the operations by employing small tools and viewing equipment into the patient’s body by means of small incisions. In manual and robotic minimally invasive surgery, surgeons do not have direct touch and natural sense of touch, due to utilization of long and often flexible instruments, and palpation is a necessity to provide perfect diagnoses. As a potential candidate, magnetorheological elastomers were investigated as a stiffness display for surgical application. To this end, three different samples of magnetorheological elastomers with various volume fraction of iron particles and one non-MRE rubber sample were fabricated. Six composite MREs were made by combining two layers of different fabricated samples. The samples were characterized under compression test and perpendicular to the applied magnetic field (MF). The compression test was carried out with the strain range of (5 - 25%) at magnetic field densities of 0, 143, 162, 198, 238, 287, 365 mT. It was observed that the elastic modulus of one-layered MREs and bi-layered MREs increase with increasing the magnetic fields. Moreover, MR-effect was enhanced via bi-layer composition, e.g. mono-layered 45%vol iron particles: 211%, bi-layered 45%vol iron particles: 253%. Afterward, a solution for the medical need of the tactile display during minimally invasive surgeries was proposed. To this end, a tactile display based on the composite magnetorheological elastomers, MiTouch , was designed and prototyped. Also, the electromechanical parameters of MiTouch were identified through a transfer function optimization and a PID controller was fine-tuned to achieve a desired stiffness. Later, validation experiments were carried out to showcase the feasibility of MiTouch for pulse examinations and maintaining a desired stiffness. The results revealed that MiTouch applied a pulsed contact force of 0.6N to the phantom finger. The results were within the range of reported pulse examination forces, i.e. 0.5-2N. In addition, the system was capable of following a desired stiffness of 4N=mm and maintaining it within a range of 4:07 +/- 0:41N/mm. In the end, results confirmed the hypothesis of the feasibility of the suggested solution for surgical applications.


identifier: Singer, Alexandra F.  (2019) Pre-service teachers' perceptions of their role as moral educators: An exploratory study.  Masters thesis, Concordia University.

abstract:
Alongside curricula, schools provide spaces for moral learning despite focusing on academic subjects. This thesis examines (1) preservice teachers’ definitions of morality, (2) their beliefs about children’s moral development, (3) their perceived role in children’s moral development, and (4) elements that influence these beliefs. Twenty-seven first-year students in a university licensure program participated in this study. Participants completed two reflections on their beliefs about their role as educators. The first reflection focused on identifying important personal values and the second focused on how children learn right from wrong. Both reflections
asked participants to envision their role as educators in sharing values and children’s learning of right from wrong. Reflections were coded qualitatively, with values, concept, and five Rs coding. Subsequently, axial coding was used with a grounded theory framework to produce a working theory about these beliefs. In the first reflection, preservice teachers explicitly explored their understandings of morality vis-à-vis values, such as respect and empathy. Participants discussed their beliefs about children’s development and learning, taking account of environmental and cognitive factors rather than providing straightforward modeling or direct instruction accounts. Finally, they discussed their perceived roles as moral educators, which were influenced by beliefs about morality, child development, and religion, which often intersected with one another, demonstrating the interconnections between these elements. Ultimately, the findings have implications on preservice teachers’ active reflection on their role as moral educators and their impact in the classroom, suggesting that preservice teacher training programs should provide opportunities for students to explore such beliefs.


identifier: Ozturk, Tugba Nur  (2019) Molecular Modeling of Ion Transport and Ion Sensing in Proteins.  PhD thesis, Concordia University.

abstract:
Molecular modeling complements conventional experiments by providing atomistic details behind the structural dynamics of transport proteins and unraveling the complex relationships among their structures and functions. In this thesis, we use molecular modeling to study the Orai channel and ProP transporter. Orai proteins function as store-operated calcium channels in most eukaryotic cells and are particularly interesting due to their high calcium selectivity, low conductance and unusual pore structures. We present molecular dynamics simulations of two Orai multimers – hexamer and tetramer – and examine their structural dynamics. The results show that the Orai tetramer retains most of the structural features of the hexamer, while creating a more tightly-packed hydrophobic pore. We then present free energy calculations of ion permeation through these multimers. To test whether the Orai pore can be opened via helix rotation, the multimers with rotated pore-forming helices were also simulated. Our results demonstrate that helix rotation significantly lowers the energy cost of ion translocation along the Orai pore, regardless of multimeric state. What depends on stoichiometry is the Ca2+ selectivity versus Na+. When opened, the hexameric pore is better adapted to Ca2+ permeation, displaying changes in relative permeabilities that are consistent with calcium-selective currents. Interestingly, the opening of the hexamer barely makes a difference for the permeation of Na+ and K+ ions, while opening the tetramer almost completely removes the barrier for these ions.
We also present our work on the E. coli ProP transporter, which pumps osmolytes into cells to prevent cellular dehydration as the cytoplasmic cation concentration increases. We built a homology model of the cytoplasmic C-terminal domain (CTD) of ProP that is implicated in osmosensing and performed molecular dynamics simulations to examine salt dependency in the CTD-membrane association. The salinity dependence of the CTD-membrane interaction does not arise from changing salt bridge patterns. In fact, it correlates with a decrease in membrane fluidity due to increasing salinity.
To our knowledge, the studies presented here are the first computational work addressing the selectivity and permeation of Orai channels in two different multimeric states, as well as building a model structure of the cytoplasmic domain of ProP.


identifier: Carru, Diane  (2019) Exploring the role of Information and Communications Technology in the experience of refugees and their service providers in the city of Montréal.  Masters thesis, Concordia University.

abstract: Since January 2017, the increased number of asylum claims made in Canada has resulted in a significantly backlogged immigration system. In Montréal, refugee claimants awaiting court hearings for months on end often face isolation and exclusion. Research has shown that refugees increasingly rely on Information and Communications Technology (ICT) to curb the effects of living in legal, cultural and social limbo. What remains unknown, however, is how service providers (community organizations, social workers, volunteers) perceive ICT and adapt their work to the omnipresence of these tools. Drawing from ethnographic data including ten in-depth interviews conducted with refugees and service providers, this thesis explores the role of ICT in refugee support networks of Montréal. Refugee participants reported using ICT to stay connected with their family abroad while developing a locally-situated network. Similarly, ICT facilitated service providers’ work and increased the engagement of the local community.  However, ICT use did not only yield positive outcomes: participants expressed concern about the problematic spread of misinformation online, and about privacy and traceability issues. Results therefore indicate that ICT can be exploited to promote social inclusion in a context of forced displacement, but also exacerbates refugees’ exposure to certain threats.


identifier: Spooner-Lockyer, Kassandra  (2019) Evanescent Lives: Archival Dissolution in a Montreal Psychiatric Hospital.  Masters thesis, Concordia University.

abstract: This thesis examines the medical files of women suffering from neurosyphilis at the Montreal psychiatric hospital Saint-Jean-de-Dieu at the beginning of the 20th century. I argue that history and the hospital functioned differently for these women, as their lives, bodies, relations of care, and narratives were left to dissolve into dust. In the very institutions meant to preserve their bodies (i.e. the hospital) and their records (i.e. the archive) and keep them whole, my participants were evanescent, passing out of sight and out of time. This thesis examines this motion towards dissolution as things go from present to absent, and material to dust and the underlying administrative and ideological mechanisms of the hospital and the archive which encourage this process and target specific histories and lives for burial. I move away from traditional methodological and representational styles of ethnography that seeks to gather and tell stories, which, if not whole are at least complete, and ask instead what stories I can tell from partial, fragmented, and unknowable subjects.


identifier: Wang, Lei  (2019) The Influence of Prevention- versus Promotion-Focused Brand Slogans on Consumer Motivated Choices and Behaviors.  Masters thesis, Concordia University.

abstract: Across four studies, I show that slogans that focus on the self-concept seem to produce predominantly negative effects on consumer motivated behavior, and this is especially true for prevention (versus promotion) slogans. In my studies, prevention slogans focused on the feared self, promotion slogans focused on the ideal self, and control slogans did not refer to the self-concept. I found reliable negative effects of prevention slogans within the financial (study 1A) and beauty goal domains (study 1B). I also provide evidence that the demotivating effects of prevention-focused slogans are at least partially attributed to consumer defensiveness. Past research suggests that people are more likely to experience anxiety after exposure to a feared, rather than ideal self. In the present research, I extend this finding by showing that prevention-focused slogans (i.e. focus on feared self) encouraged defensive coping, instead of directly addressing the source of the threat. Specifically, exposure to prevention slogans generated a higher likelihood to engage in fluid compensation, a tendency to redirect attention to an unrelated goal and engage in behaviors aligned with this alternate goal (study 3). Conversely, the motivational effects of promotion-focused slogans (i.e. focus on ideal self) demonstrated a more positive, but more subtle pattern of direct coping. Promotion slogans only motivated goal-congruent behaviors among people with high self-consciousness (study 2).


identifier: Pyne Feinberg, Pohanna  (2019) Walking With: An Invitation > Insights into the Pedagogical Force of Walking from the Perspectives of Artists who Walk as an Aspect of Their Practice.  PhD thesis, Concordia University.

format: text video video video video video video video video video video video video

abstract:
Walking With explores the pedagogical potential of walking as a form of artistic inquiry and expression. Walking is relational and politically imbued; we are inspirited by a constellation of encounters with people, places and things that inform who we become. As we leave our trace, our presence also shapes where we walk. Through feminist research-creation, including in-depth interviews with twelve artists, these guiding questions were considered: What insights can artists offer about the pedagogical force of walking – the affective and resonant ways that we become ourselves in relation to place? How might these insights inform walking-based pedagogy in art education? Furthermore, given that the contributing artists are women, how might the nuance of their experiences complexify the international discourse on walking art practices? As a localized study of contemporary artists who work with various media in the region of Tiohtiá:ke–Mooniyang–Montréal, a range of motivations and ruminations are revealed. Audio recordings and digital photographs were gathered during the interviews and audio-visual portraits were then created as interpretations of the artist’s insights. The portraits are presented online – www.walkingwith.ca – as an invitation to others to join in reflection about the significance of walking. A series of questions, titled “Reflections to walk with”, accompany each portrait as a point of departure for further consideration and discussion. The thesis project is complimented by an autoethnographic text that describes three epiphanies that compelled the researcher to focus on this topic and offers a summary of the research-creation process that brought it to fruition.

The contributing artists: Cam, Sylvie Cotton, Natalie Doonan, Ette, Dominique Ferraton, Sylvie Laplante, Andra McCartney, Émilie Monnet, Taien Ng-Chan, karen elaine spencer, Victoria Stanton and Kathleen Vaughan.


identifier: Daghyani, Masoud  (2019) Efficient Computation of Log-likelihood Function in Clustering Overdispersed Count Data.  Masters thesis, Concordia University.

abstract: In this work, we present an overdispersed count data clustering algorithm, which uses the mesh method for computing the log-likelihood function, of the multinomial Dirichlet, multinomial generalized Dirichlet, and multinomial Beta-Liouville distributions. Count data are often used in many areas such as information retrieval, data mining, and computer vision. The multinomial Dirichlet distribution (MDD) is one of the widely used methods of modeling multi-categorical count data with overdispersion. In recent works, the use of the mesh algorithm, which involves the approximation of the multinomial Dirichlet distribution's (MDD) log-likelihood function, based on the Bernoulli polynomials; has been proposed instead of using the traditional numerical computation of the log-likelihood function which either results in instability, or leads to long run times that make its use infeasible when modeling large-scale data. Therefore, we extend the mesh algorithm approach for computing the log likelihood function of more flexible distributions, namely multinomial generalized Dirichlet (MGD) and multinomial Beta-Liouville (MBL). A finite mixture model based on these distributions, is optimized by expectation maximization, and attempts to achieve a high accuracy for count data clustering. Through a set of experiments, the proposed approach shows its merits in two real-world clustering problems, that concern natural scenes categorization and facial expression recognition.


identifier: Dong, Yingting  (2019) The Effect of Suspensions on Liquidity of the Chinese Stock Market.  Masters thesis, Concordia University.

abstract: In this paper, I study the effect of suspensions on liquidity of stocks in the same industry or province in the Shanghai Stock Exchange A-share market from 1997 to 2017. I find that each additional suspended stock has a significant and positive effect on the bid-ask spread of non-suspended stocks in the same industry or province. Besides, suspensions lasting for a longer period of time have weaker impact on the liquidity of informationally and regionally related stocks than suspensions lasting for a short period. What’s more, suspensions caused by different reasons have different impact on liquidity of related stocks. For suspensions due to limit hit, they are significantly and negatively related to the spread of non-suspended stocks in the same industry or province. This is due to the fact that according to the regulation that stocks hitting price limits for several continuous days will be suspended what leads to higher predictability of this type of suspension. But suspensions caused by negative news and neutral news have a significant and positive impact on illiquidity of other non-suspended stocks in the same industry or province. Thereby suspensions caused by negative news have a larger impact on the liquidity of informationally and regionally related stocks than suspensions caused by neutral news.