identifier: WANG, Chengyin  (2018) On Estimators of a Spectral Density Function.  Masters thesis, Concordia University.

abstract: This thesis presents two main approaches to estimating the spectral density of a stationary time series, that are based on the classical periodogram. Both of these are related to the non-parametric density estimation. One is the kernel spectral density estimator while the other one is the Bernstein polynomial spectral density estimator. We have also introduced the method to determine the optimal smoothing parameters for estimating the spectral density of a stationary zero-mean process. Finally, the thesis concludes with a simulation study in order to examine the finite sample properties of the proposed spectral density estimators.


identifier: Cao, Yuhan  (2018) On Transformation Based Circular Density Estimators.  Masters thesis, Concordia University.

type: Thesis NonPeerReviewed

abstract: Estimation of the probability density function for circular data is an important topic in statistical inference. In this thesis, I would like to introduce two transformation based methods for estimating probability density function in this context. One is derived from traditional kernel density estimator and the other one comes from the Bernstein polynomial estimator (Chaubey, 2017). We know both of the kernel density estimator (Silverman, 1986) and Bernstein polynomial estimator (Babu, Canty and Chaubey, 2002) are appropriate for the case of linear data, transformation of circular data to linear data would bring extreme simplicity to estimation of probability density function in the case of circular data by back transformation. I will conduct a simulation study to compare these methods with respect to their global and local errors. We find through our simulation study that transformed kernel density estimator has a stronger ability to alleviate the boundary problems than transformed Bernstein polynomial estimator, however, their overall performance is pretty much similar in the central part of the distribution. Therefore, in general we can say transformed kernel density estimator leads to a better method as compared to the transformed Bernstein polynomial estimator, however further research may be needed to study other transformations.


identifier: Nguyen, Phuoc Huy Nhut  (2018) Earth Pressures of Overconsolidated Collapsible Soil Subjected to Inundation.  PhD thesis, Concordia University.

abstract:
Collapsible soils are known as problematic soils, which can be found in many regions around the world. Collapsible soils possess considerable strength when they are dry; however, when they are inundated, they lose their strength and exhibit excessive settlement. The amount of soil collapse increases with the increase of the so-called collapse potential “Cp”, the wetting zone, and the degree of saturation (S). Accordingly, maximum collapse will take place due to full saturation. Collapsible soils can be inundated by heavy and continuous rainfall, excessive irrigation, broken water/sewer lines, or by rising the ground water. Furthermore, collapsible soils can be also found in construction site, in compacted fine soils at low water content (less than the optimum water content). Consequently, it is impossible to avoid construction on collapsible soils, which are potential for excessive settlement, differential settlement, landslides and falls, earth cracks. This type of soil has been responsible for damaging variety of civil engineering structures, loss of lives. Construction on such kind of soil shows extraordinary geotechnical problems, retaining walls are not an exception. With civilization, backfills behind retaining walls made of collapsible soils are widely used in practice. The earth pressures acting on these walls experience radical changes when the backfills of collapsible soils are wetted.
In the literature, there are lack of theories/methods for estimating the earth pressures acting on walls retaining collapsible soils. In this study, experimental investigations on at-rest and passive earth pressures of overconsolidated collapsible soil on retaining walls were conducted.A prototype model of a vertical wall, retaining horizontal backfill of collapsible soil, was developed in the laboratory. Collapsible soil was prepared in the laboratory by mixing kaolin clay with fine sand. The model was instrumented to measure the earth pressure at strategic points on the wall, the total earth pressure acting on the wall, and the overconsolidation ratio (OCR) of the soil. Tests were conducted on the wall retaining collapsible soil at the dry and at fully saturated conditions for both the at-rest and passive earth pressures. The test results showed that both the at-rest and passive earth pressures increased with the increase of the collapse potential (Cp) and overconsolidation ratio (OCR) for the dry soil. At full saturation, the at-rest and passive earth pressures reduced considerably. Generally, the higher the collapse potential of the collapsible soil, the larger the decrease in the at-rest and passive earth pressures of the soil when the soil gets inundated.
In this investigation, for the case of at-rest earth pressure, empirical formulae were developed to determine the coefficient of at-rest earth pressure (K0) of the dry and saturated overconsolidated collapsible soil. For the case of passive earth pressure, analytical model was developed. Accordingly, design theory was presented for estimating the coefficient of passive earth pressure (Kp) of overconsolidated collapsible soil at the dry and saturated conditions. Moreover, considering for the case of presence of unsaturated states of collapsible soil in practice, design charts were developed to assist designers in approximating the coefficient of at-rest (K0) and passive (Kp) earth pressures of this soil at different degree of saturation.


identifier: Ghamary, Yasser  (2018) Multi-Project Multi-Mode Resource Constrained Scheduling Problem with Material Ordering.  Masters thesis, Concordia University.

abstract: In Multi–mode Project Scheduling with Resource Constrained (MPSRCP), activities are sequenced under resource limitation. In this thesis, an extension of the problem is considered. Multi-project multi-mode resource constrained scheduling problem with material ordering is studied. Bonus and penalty are taken into account in solving the considered problem as it is the case in many different industries. A literature review is presented and various solution methods for solving the considered and similar problems are studied. A new mathematical model is proposed considering a multi-project version of the problem. A new decomposition based heuristic to solve the problem is developed in this thesis. The approach is to use three separated mathematical models for each part of the problem. The developed heuristic is examined using various example problems with different features and randomly generated data. It can generate close-to-optimal solutions for all tested example problems with much reduced computational time when off-shelf optimization software was used. The developed math model and heuristic method are applied to a larger size case study based on a practical system in a manufacturing company in northern Ontario.


identifier: Wen, Yuxin  (2018) Do Target Shareholders Lose To Private Acquirers?  Masters thesis, Concordia University.

abstract:
Abstract
Focusing on private equity firms, I find that targets receive a higher premium when acquirers are private firms. When the target management is in the private acquirer’s team, the targets receive a lower premium. When I look at cumulative abnormal returns (CARs), targets of private acquirers have lower CARs than those of public acquirers, and private acquisitions with management participation have higher CARs than without management participation. Also, private acquisitions are more likely to be successful than public acquisitions, and within private acquisitions, those with target’s management participation have even better odds.


identifier: Elsaadany, Mahmoud  (2018) Enabling Technologies for Internet of Things: Licensed and Unlicensed Techniques.  PhD thesis, Concordia University.

abstract:
The Internet of Things (IoT) is a novel paradigm which is shaping the evolution of the future Internet. According to the vision underlying the IoT, the next step in increasing the ubiquity of the Internet, after connecting people anytime and everywhere, is to connect inanimate objects. By providing objects with embedded communication capabilities and a common addressing scheme, a highly distributed and ubiquitous network of seamlessly connected heterogeneous devices is formed, which can be fully integrated into the current
Internet and mobile networks, thus allowing for the development of new intelligent services available anytime, anywhere, by anyone and anything. Such a vision is also becoming known under the name of Machine-to-Machine (M2M), where the absence of human interaction in the system dynamics is further emphasized.
A massive number of wireless devices will have the ability to connect to the Internat through the IoT framework. With the accelerating pace of marketing such framework, the new wireless communications standards are studying/proposing solutions to incorporate the services needed for the IoT. However, with an estimate of 30 billion connected devices, a lot of challenges are facing the current wireless technology.
In our research, we address a variety of technology candidates for enabling such a massive framework. Mainly, we focus on the  nderlay cognitive radio networks as the unlicensed candidate for IoT. On the other hand, we look into the current efforts done by the standardization bodies to accommodate the requirements of the IoT into the current cellular networks.
Specifically, we survey the new features and the new user equipment
categories added to the physical layer of the LTE-A.

In particular, we study the performance of a dual-hop cognitive radio network sharing the spectrum of a primary network in an underlay fashion. In particular, the cognitive network consists of a source, a destination, and multiple nodes employed as amplify-and-forward
relays. To improve the spectral efficiency, all relays are allowed to instantaneously transmit to the destination over the same frequency band. We present the optimal power allocation that maximizes the received signal-to-noise ratio (SNR) at the destination while satisfying the interference constrains of the primary network. The optimal power allocation is obtained through an eigen-solution of a channel-dependent matrix, and is shown to transform the transmission over the non-orthogonal relays into parallel channels. Furthermore, while the secondary destination is equipped with multiple antennas, we propose an antenna selection scheme to select the antenna with the highest SNR. To this end, we propose a clustering scheme to subgroup the available relays and use antenna selection at the receiver to extract the same diversity order. We show that random clustering causes the system to lose some of the available degrees of freedom. We provide analytical expression of the outage probability of the system for the random clustering and the proposed maximum-SNR clustering scheme with antenna selection. In addition, we adapt our design to increase the energy-efficiency of the overall network without significant loss in the data rate.
In the second part of this thesis, we will look into the current efforts done by the standardization bodies to accommodate the equirements of the IoT into the current cellular networks. Specifically, we present the new features and the new user equipment categories added to the physical layer of the LTE-A. We study some of the challenges facing the LTE-A when dealing with Machine Type communications (MTC). Specifically, the MTC Physical Downlink control channel (MPDCCH) is among the newly introduced features in the LTE-A that carries the downlink control information (DCI) for MTC devices. Correctly decoding the  PDCCH, mainly depends on the channel estimation used to compensate for the channel errors during transmission, and the choice of such technique will affect both the complexity and the performance of the user equipment. We propose and assess the performance of a simple channel estimation technique depends in essence on the Least Squares (LS) estimates of the pilots signal and linear interpolations for low-Doppler channels associated with the
MTC application.


identifier: Moore, Patrick Aaron  (2018) Some Results for FO-definable Constraint Satisfaction Problems Described by Digraph Homomorphisms.  Masters thesis, Concordia University.

abstract: Constraint satisfaction problems, or CSPs, are a naturally occurring class of problems which involve assigning values to variables while respecting a set of constraints. When studying the computational and descriptive complexity of such problems it is convenient to use the equivalent formulation, introduced by Feder and Vardi, that CSPs are homomorphism problems. In this context we ask if there exists a homomorphism to some target structure. Using this view many tools and ideas have been introduced in combinatorics, logic and algebra for studying the complexity of CSPs. In this thesis we concentrate on combinatorics and give characterization results based on digraph properties. Where previous studies focused on CSPs defined by a single digraph with lists we extend our relational structures to consist of many binary relations which each individually describe a distinct digraph on the structures universe. A majority of our results are obtained by using an algorithm introduced by Larose, Loten and Tardif which determines whether a structure defines a CSP whose homomorphism problem can be represented by first order logic. Using this tool we begin by completely classifying which of these structures are FO-definable when each of the relations defines a transitive tournament. We then generalize a characterization theorem, first given by Lemaître, to include structures containing any finite number of digraph relations and lists. We conclude with examples of obstructions and properties that can determine if a particular relational structure has a CSP which is FO-definable and how to construct such structures.


identifier: Eftekhari, Jasmine  (2018) The Effects of Urban Rail Rapid Transit Station Types on Housing Prices in Toronto and Vancouver, Canada.  Masters thesis, Concordia University.

abstract:
Previous research has shown that proximity to transit stations correlates positively with housing values. However, it is also possible that negative impacts on housing prices could result from negative externalities associated with stations and their surrounding tracks. The overall goal of this study is to distinguish effects of urban rail rapid transit which raise housing prices from those which lower housing prices while isolating the impact of station type.
This thesis examines the impact of urban rail rapid transit station types (underground, ground-level, or elevated), on values of adjacent residential properties in Toronto and Vancouver Metropolitan Areas. This is done through applying a hedonic price modelling methodology to analyze housing values in those two cities. Results indicated that on average, proximity to urban rail rapid transit stations led to higher residential property values and that the type of the closest urban rail rapid station was among the factors determining the amount of this capitalization. This relationship varied based on the city, characteristic of the neighbourhood, those of the transit infrastructure and the property itself.


identifier: Glovaci, Iulia  (2018) Dopaminergic Facilitation of Synaptic Transmission in Layer II of the Lateral Entorhinal Cortex.  PhD thesis, Concordia University.

abstract:
The lateral entorhinal cortex (LEC) plays an important role in the sensory and mnemonic functions of the medial temporal lobe, most notably in regard to object-related information and olfaction processing. The modulation of synaptic inputs in the LEC may have important implications for learning and memory, in part by affecting the synaptic output of the superficial layers of the LEC to the hippocampus. The superficial layers of the lateral entorhinal cortex are strongly innervated by midbrain dopaminergic neurons. Dopamine can modulate synaptic strength in a dose-dependent manner; high concentrations of dopamine suppress excitatory synaptic transmission, whereas lower concentrations of dopamine (1-10 µM) facilitate it. Therefore, low dopamine levels are likely to promote synaptic transmission in the LEC, and thus provide a mechanism for promoting mnemonic processes. However, the underlying intracellular signalling cascade linking dopamine receptor activation to glutamatergic transmission in layer II LEC neurons has remained hitherto unknown.

The work presented here used single-cell, patch-clamp recordings to characterize the signalling pathway linking dopamine-receptor activation to increases in synaptic transmission in layer II LEC cells. The first set of experiments in this thesis used bath application of dopamine and current-clamp recordings to investigate the dopaminergic facilitation of excitatory postsynaptic potentials (EPSPs) in layer II neurons of the rat lateral entorhinal cortex in vitro. Results indicated that activation of dopamine D1-like receptors lead to increases in AMPA receptor-mediated responses in a manner that was dependent upon the cAMP-protein kinase A (PKA) pathway and protein phosphatase 1 (PP-1). The second series of experiments assessed the contribution of phosphatidylinositol (PI)-linked D1-like receptors to the dopaminergic facilitation of synaptic transmission. Experiments demonstrated that, in addition to activation of the cAMP-PKA pathway, dopamine can lead to the facilitation of synaptic transmission that is reliant on a signaling cascade dependent on PI-linked D1-like receptors, phospholipase C, release of calcium from internal stores, and protein kinase C. In a third series of experiments, fluorescence calcium imaging was used to monitor changes in intracellular calcium induced by dopamine. Bath application of dopamine and the PI-linked dopamine agonist induced a reliable and reversible increase in fluorescence in fan, but not pyramidal, entorhinal cells. This increased fluorescence was correlated with a reversible increase in the amplitude of evoked synaptic currents. Together, the results demonstrate that both the cAMP-PKA and the PLC-DAG-IP3 signalling pathways may contribute to transient increases in synaptic strength that could mediate enhanced sensory and mnemonic function in the entorhinal cortex during release of dopamine.


identifier: Yates, Matthew C. ORCID: https://orcid.org/0000-0002-9199-1078 <https://orcid.org/0000-0002-9199-1078>  (2018) Evaluating the Relative Importance of Habitat and Genetic Predictors of Fitness Correlates and the Effectiveness of Genetic Monitoring Tools for Populations Experiencing Novel Environmental Change.  PhD thesis, Concordia University.

abstract: Determining how organisms respond, at a population-level, to novel environmental conditions is an important area of research in the rapidly changing Anthropocene. Many factors have been theorized to affect population-level responses, including the nature of the habitat change, the genetic characteristics of exposed populations, and the levels of plasticity populations exhibit across environments. Using a combination of meta-analytical techniques and empirical experimentation, my thesis examined the relative influence of genetic and environmental factors on population-level responses to novel environments. For Chapter 1, I conduct a meta-analysis using reciprocal transplants and common garden experiments in novel environments with known census population sizes (Nc) to test the effect of Nc on survival in novel environments. I found that large populations exhibited stronger local adaptation, but that this comes with potential trade-offs in novel environments. For Chapter 2, I conducted translocations of brook trout (Salvelinus fontinalis) to novel pond environments to test the relative importance of habitat and genetic factors (genomic diversity (Ho) and effective number of breeders (Nb)) on fitness correlates. I found that habitat overwhelmingly predicted performance, with little influence of genetic factors on performance in novel environments. For Chapter 3, I tested if phenotypic plasticity in body morphology was released in the Chapter 2 transplants and evaluated if released plasticity was correlated with Ho. I found limited evidence that phenotypic plasticity was released, and no evidence that Ho affected phenotypic diversity in novel environments.  In Chapter 4 I evaluated whether Nb can be used to effectively monitor Nc in salmonids and found that, overall, it could not. Collectively, my research demonstrates that habitat is the primary predictor of fitness correlates in novel environments, with Nc, Nb, and Ho explaining little variation in performance or plasticity across studies.  Our results provide evidence that small, low-diversity populations may often be capable of persistence and potentially adaptation, and further highlight the importance of conserving habitat. Furthermore, my research demonstrates that there is no “free lunch” – Nb cannot be used to “cost-effectively” monitor Nc in populations of conservation concern, which require actual census operations to monitor changes in Nc.


identifier: Leonov, Anna  (2018) Mechanisms Through Which Lithocholic Acid and Caloric Restriction Delay Yeast Chronological Aging.  PhD thesis, Concordia University.

abstract:
The objective of studies described in this thesis was to investigate mechanisms through which lithocholic acid (LCA) and caloric restriction (CR) delay chronological aging of the budding yeast Saccharomyces cerevisiae. My overall hypothesis was that each of these aging-delaying interventions slows down yeast chronological aging by targeting different cell biological processes. Findings presented here support this hypothesis. Indeed, I found that LCA delays the chronological mode of S. cerevisiae aging by altering the lipid composition of mitochondrial membranes. I demonstrated that these LCA-driven alterations in mitochondrial membrane lipidome elicit distinct changes in the abundance of many mitochondrial proteins, thereby enabling the establishment of a geroprotective pattern of mitochondrial functionality. These findings provided the first comprehensive evidence that mitochondrial lipidome plays an essential role in defining longevity of chronologically aging yeast. I found that CR slows yeast chronological aging through a different mechanism. This previously unknown mechanism links the chronological mode of S. cerevisiae aging to cell cycle regulation and controlled cell differentiation. The key aspects of my hypothesis-driven investigation of these two different mechanisms of aging delay are outlined below.
The Titorenko laboratory has previously found that exogenously added LCA delays yeast chronological aging. The laboratory has demonstrated that LCA enters the yeast cell, is sorted to
iv
mitochondria, resides in both mitochondrial membranes, changes the relative concentrations of different membrane phospholipids, triggers changes in the concentrations of many mitochondrial proteins, and alters some key aspects of mitochondrial functionality. Based on these observations, I hypothesized that the LCA-driven changes in mitochondrial lipidome may have a causal role in the remodeling of mitochondrial proteome, which may in turn alter the functional state of mitochondria to create a mitochondrial pattern that delays yeast chronological aging. To test this hypothesis, I investigated how the ups1Δ, ups2Δ and psd1Δ mutations that eliminate enzymes involved in mitochondrial phospholipid metabolism influence the mitochondrial lipidome. I also assessed how these mutations affect the mitochondrial proteome, influence mitochondrial functionality and impinge on the efficiency of aging delay by LCA. My findings provide evidence that 1) LCA initially creates a distinct pro-longevity pattern of mitochondrial lipidome by proportionally decreasing phosphatidylethanolamine and cardiolipin concentrations to maintain equimolar concentrations of these phospholipids, and by increasing phosphatidic acid concentration; 2) this pattern of mitochondrial lipidome allows to establish a specific, aging-delaying pattern of mitochondrial proteome; and 3) this pattern of mitochondrial proteome plays an essential role in creating a distinctive, geroprotective pattern of mitochondrial functionality.
A yeast culture grown in a nutrient-rich medium initially containing 2% glucose is not limited in calorie supply. When yeast cells cultured in this medium consume glucose, they undergo cell cycle arrest at a checkpoint in late G1 and differentiate into quiescent and non-quiescent cell populations. Studies of such differentiation have provided insights into mechanisms of yeast chronological aging under conditions of excessive calorie intake. CR is an aging-delaying dietary intervention. I hypothesized that CR may slow down yeast chronological aging by eliciting specific changes in cell cycle regulation and controlled cell differentiation. To test this hypothesis, I
v
investigated how CR influences the differentiation of chronologically aging yeast cultures into quiescent and non-quiescent cells, and how it affects their properties. I found that CR extends yeast chronological lifespan via a mechanism linking cellular aging to cell cycle regulation, maintenance of quiescence, entry into a non-quiescent state and survival in this state. My findings suggest that CR delays yeast chronological aging by causing specific changes in the following: 1) a checkpoint in G1 for cell cycle arrest and entry into a quiescent state; 2) a growth phase in which high-density quiescent cells are committed to become low-density quiescent cells; 3) the differentiation of low-density quiescent cells into low-density non-quiescent cells; and 4) the conversion of high-density quiescent cells into high-density non-quiescent cells.


identifier: Rousseau, Yannick  (2018) A Novel, Generic Approach To Simulate Bank Retreat In Alluvial River Channels.  PhD thesis, Concordia University.

abstract: Despite the importance of bank erosion in rivers, most computational fluid dynamics (CFD) models have limited capacity to examine bank retreat and channel-floodplain interactions, as they lack bank stability algorithms and ignore vegetation effects. This research seeks to develop a numerical model to improve our understanding of key properties of bank material and vegetation cover with respect to lateral erosion in river meanders at intermediate spatial (5−10 meander bends) and temporal (2−3 years) scales. Following a comparison of six different morphodynamic models for three sinuous laboratory configurations, the CFD model TELEMAC-2D was chosen to receive a newly developed bank retreat module that respects geotechnical principles and integrates spatial analysis concepts. It was tested against morphological datasets from two contrasted river reaches, the semi-alluvial Medway Creek (Ontario) and alluvial St. François River (Quebec). Statistical analysis, combined with the use of machine learning algorithms, demonstrate that the coupled model is able to fit observed bank retreat location and extent. Some local disagreement with observations along Medway Creek seems associated with the heterogeneity of soil material and stratigraphy, and in vegetation cover present at the field site. The coupled model was also used to identify key geotechnical parameters and optimal parameter values for the studied reaches. An epistemological reflection on the purpose of modelling in fluvial geomorphology leads to the conclusion that the primary model strength lies in its ability to provide explanations on bank retreat mechanisms. Further research should seek to test more thoroughly morphodynamic modelling in complex geomorphological environments.


identifier: Payarou, Tamanwè  (2018) Micro-Photosynthetic Power Cell Modeling, Sensing, and Energy Harvesting.  Masters thesis, Concordia University.

abstract: Micro-photosynthetic cells (μ-PSC) are considered as self-sustaining sources of energy that can be used for powering mobile microelectromechanical systems (MEMS) and remotely located sensor networks. Their ability to generate power under both dark and illuminated conditions, self-restoring capabilities, environmental friendliness, compactness, and low operation and maintenance cost are some of the advantages. Newly developed μ-PSCs can produce a maximum power density of several hundreds of


identifier: Shahkar, Shahram  (2018) Condition Monitoring of Gas Turbines using Acoustic Emissions.  Masters thesis, Concordia University.

abstract:
Acoustic emission (AE) technology has recently found its way in condition monitoring of rotary equipment due to its advantage of earlier detection of defects and anoma- lies in comparison to vibration analysis. However, there has been very little industrial application of AE signals for condition monitoring of safety-critical equipment if any, partly due to the diffculty in processing, interpreting and classifying the acquired data in a highly reliable fashion. The motivation in this thesis was to develop a methodol- ogy for inferring health related information in a gas turbine without intruding the engine.
Our work has targeted a broad class of rotary equipment known as cyclostationary processes, therefore, instead of analyzing particular AE samples of gas turbines we have tried to build a mathematical framework that would suit any arbitrary machine comply- ing certain conditions. The result of our work mainly encompasses a feature extraction technique that eliminates the random e↵ects associated with a gas turbine AE signal, and a hypothetical testing method for classification of AE signals with any desirable level of certainty, subject to a set of assumptions and conditions.
We have validated our methodologies and derivations using actual real-life gas turbine AE signals, and compared our solutions with some of the techniques published in the literature.


identifier: El Said, Feras Mohammad  (2018) Road Management Systems to Support Bicycling: A Case Study of Montreal’s Bike Network.  Masters thesis, Concordia University.

abstract:
Bicycling is a sustainable mode of transportation given its health benefits, reduced air and noise pollution, savings in fuel consumption, and role in shifting demand away from the automobile. A significant increase of bicycle users is an aim of many cities around the world. Responding to this, various cities announced their strategies to extend and/or upgrade their bikeway
networks. However, there is a disconnection between the strategies to support bicycles and road management systems, which are typically used for optimal scheduling of maintenance and interventions for roads’ infrastructure. Traditional road management systems consider neither the need to sustain bicycle pathways at good levels of service, nor consider bicycling demand to prioritize their selection. This thesis extends road management systems to support bicycling networks. This enables the ability to optimally allocate available resources for sustaining the surface of bicycle pathways in good condition, and implement physically-separated bicycle lanes to enhance safety conditions and encourage bicycle ridership. A simple formulation of bicycle demand is proposed; it employs the capabilities of smartphones for collecting and estimating bicycling demand based on GPS trajectories of cyclists. Goal programming optimization is applied to address scheduling of maintenance and upgrade investments of pathways. Two scenarios are investigated with different annual budgets. The results show that the first scenario allows a rapid upgrade of existing bicycle lanes to protected paths while accomplishing good conditions of pavements. However, the second scenario is not able to prevent the deterioration of pavement segments.


identifier: Khan, Abdullah  (2018) Impact of charged silica nanoparticles on the biophysical properties of lung surfactant.  Masters thesis, Concordia University.

abstract: As oxygen is inhaled it has to first cross a very thin layered membrane, lung surfactant, before it can enter the bloodstream. This lung surfactant membrane is composed of saturated and unsaturated phospholipids and membrane proteins which serve to reduce the surface tension at the air-liquid interface of the alveoli preventing alveolar collapse. To maintain this function through repetitive compression-expansion cycles, the film employs a mechanism of reversible reservoir formation and exhibits a high degree of fluidity. The inhalation of nanoparticulate may interfere with the functional properties of pulmonary surfactant including lowering the film collapse, altering viscoelastic properties and modifying lipid reservoir formation. This study aims to determine the degree to which nanoparticles interfere with the phase structure, compressibility, and viscoelastic properties when they deposit on the lipid membrane. The lung surfactant films are modelled using monolayers comprising either lipid-only mixtures or a natural membrane extract, namely Infasurf (a clinical formulation containing both extracted lipids and proteins). Surface pressure-area isotherms, Brewster angle microscopy, rheological measurements and grazing incidence x-ray diffraction data of films in the absence and presence of cationic and anionic silica nanoparticles are presented and discussed. The charge was found to play an important role with cationic nanoparticles having a greater impact on structural properties while anionic nanoparticles affect the viscoelastic properties of the films.


identifier: Hill, Nicole L.  (2018) Assessing limitations on reintroduction success: the influence of spawning habitat and thiamine deficiency on Atlantic salmon in Lake Champlain.  Masters thesis, Concordia University.

abstract: With the decline of freshwater fish populations, reintroductions are becoming more prevalent. In this study, we evaluated two limiting factors on the reintroduction success of Atlantic salmon (Salmo salar) within the Lake Champlain Basin: 1) the effects of dam removal on spawning habitat availability; and 2) the influence of thiamine deficiency, caused by the consumption of non-native alewife, on the survival and behavior of salmon embryos. The removal of the Willsboro dam increased availability of spawning habitat for Atlantic salmon by allowing them to access large areas of good quality habitat upstream of the former dam site and improving the quality of the small area of habitat available downstream. However, reproductive success may still be limited by thiamine deficiency. High young-of-the-year mortality occurred in families with egg thiamine levels up to 8.5 nmol/g, indicating a larger influence on recruitment then previously thought based on the 1.1nmol/g threshold for Atlantic salmon given in the literature. Though we did not find any behavioral evidence to suggest low thiamine embryos could not partake in early feeding, which may help to naturally mitigate the effects of the deficiency, recruitment remains low within the basin, suggesting the potential need for more controlled management. While this study helps to fill a gap in the literature on reintroduction monitoring and demonstrates the complex nature of population reestablishment, the results also contribute to the overall knowledge on dam removal and thiamine deficiency, which can be applied to research and management outside of the framework of reintroductions.


identifier: Sundaresan, Navaneethan ORCID: https://orcid.org/0000-0001-8130-269X <https://orcid.org/0000-0001-8130-269X>  (2018) A Study of negative feedback damping property of roll-coupled hydro-pneumatic suspensions.  Masters thesis, Concordia University.

abstract:
The design of a vehicle suspension involves complex compromises due to conflicting ride comfort and handling requirements. High load capacity and high mass center commercial vehicles, especially, impose greater design challenges due to their relatively low rollover immunity. Road vehicles, invariably, employ auxiliary roll stiffeners such as antiroll bars to realize a better compromise among the roll dynamic and ride comfort performance. The anti-roll bars, however, add considerable weight, exhibit negligible damping and cause stronger coupling between the roll and vertical modes. Alternatively, roll-connected hydro-pneumatic suspensions offer superior anti-roll performance, while preserving the soft vertical ride characteristics. Reported studies have shown that such suspensions can provide anti-roll characteristics similar to an antiroll bar but with considerable roll damping and less weight. The feedback effects of the hydraulic couplings in such suspensions yield negative damping force in the vertical mode, which have not yet been explored.
This thesis research presents a systematic study of negative damping features of the roll-coupled hydro-pneumatic suspensions and its significance for realizing variable damping properties. Three different configurations of hydro-pneumatic struts were conceived for realizing hydraulic couplings in the roll plane. Analytical models of the roll-coupled suspensions were formulated considering ideal gas law, turbulent flows through orifices and damping valves, laminar flows through interconnections, floating piston dynamics and fluid compressibility. The analytical formulations were used to describe the negative damping feature attributed to the flow feedbacks. The vertical and roll mode damping and stiffness properties of the proposed configurations were derived via analytical relations, which showed that hydraulic couplings yield high roll stiffness and damping with only minimal effect on the vertical mode properties. The simulation results demonstrated two negative damping force components of a strut attributed to flows through the interconnecting pipes and flows through orifices in the connected strut. These negative damping force components, however, contributed to only positive roll damping moment. A methodology to enhance negative damping force of the connected struts was proposed for realizing variable damping properties similar to those of the conventional damping valves. Deployments of small size multiple interconnections or the flow-control valves across the struts resulted in comprehensive magnitudes of negative damping force components.  Simulation results were obtained under lateral acceleration excitation idealizing the centrifugal force encountered during a steady-turn maneuver, a road bump, and in-phase and out-of-phase harmonic road excitations. The results were obtained for unconnected and connected struts with and without the damping valves and interconnection flow valves. Comparisons of the results revealed that interconnection valves can provide variable damping properties similar to the damping valves. The interconnection valves, however, offer greater design/tuning flexibility since these are mounted externally. The results suggested that further efforts in parameterization of the coupling flows will be worthy for realizing optimal damping properties of the roll-coupled hydro-pneumatic suspensions.


identifier: Enoch, Julian  (2018) Advanced Column Generation Decompositions for Optimizing Provisioning Problems in Optical Networks.  Masters thesis, Concordia University.

abstract:
With the continued growth of Internet traffic, and the scarcity of the optical spectrum, there is a continuous need to optimize the usage of this resource. In the process of provisioning optical networks, telecommunication operators must deal with combinatorial optimization problems that are NP-complete. One of these problems is the Routing and Wavelength Allocation (RWA) which considers the fixed frequency grid, and the Routing and Spectrum Allocation (RSA) which is defined for the flexible frequency grid. While the flexible frequency grid paradigm attempted to improve the spectrum usage, the RSA problem has an additional spectrum dimension that makes it harder than the RWA problem.
In this thesis, in continuation of the previous studies, and using the advanced techniques of Integer Linear Programing, we propose a Column Generation algorithm based on a Lightpath decomposition which we implement for both the RWA and the RSA problems. This algorithm proved to be the most efficient so far producing optimal or near optimal solutions, and improving the computation times by two orders of magnitude on average. This algorithm is based on the approach of finding the right decomposition scheme as to be able to solve the Pricing Problem in a polynomial time. This approach can be used in other optimization problems.
In addition, we consider the same Configuration decomposition as the previous studies, and we propose an algorithm based on Nested Column Generation. We implemented this algorithm for both the RSA and the RWA problems, which led to a considerable improvement on the previous algorithms that use the same Configuration decomposition. This Nested Column Generation approach can be adopted in other optimization problems.


identifier: Hammoudi, Rima  (2018) The Bookstagram Effect: Adolescents' Voluntary Literacy Engagement on Instagram.  Masters thesis, Concordia University.

abstract: This qualitative study is the first to explore bookstagram, a relatively new social media phenomenon whereby Instagram users dedicate their feed to showcasing books and reading-related activities. Specifically, this study explored adolescents' experiences of bookstagram to gain a better understanding of what motivates them towards voluntary literacy engagement. The bookstagram and reading experiences of 10 adolescent bookstagrammers were explored through semi-structured interviews and a questionnaire. The interviews were coded according to types of pleasure experienced in adolescents' free-choice reading (Wilhelm, 2016), related themes derived from the data, and themes informed by the literature on social media. The findings reinforced Wilhelm's finding that pleasure is at the heart of adolescents' free-choice reading, and further showed that bookstagram enriched adolescents' experiences of social pleasure connected to reading. The findings also revealed that bookstagram enhanced participants' literacy practices, leading them to read more, branch out into different genres, read more attentively, and embrace their enjoyment of reading. Self-presentation on bookstagram was found in participants' references to identity and self-expression on social media, and was considered in terms of its influence on participants' experiences of and motivations to bookstagram. The topics of followerships and sponsorships also emerged, although neither acted as motivations to bookstagram. Overall, this study illustrated that bookstagram gave adolescent readers an opportunity to enhance their pleasure in free-choice reading by exposing them to a community of book lovers who are as excited about reading as they are. Implications include integrating bookstagram in literacy curricula to appeal to adolescents' reading interests.


identifier: Sambe, Mariam Mekdelawit  (2018) Voices for Change in HIV/AIDS Education in Ethiopia.  PhD thesis, Concordia University.

abstract:
Drawing on data I compiled from five years of critical ethnography and photovoice through the conceptual framework of ‘critical bricolage’, I examined AIDS education programs in Addis Ababa, Ethiopia. The main objective of this doctoral thesis was to evaluate formal AIDS education as an agent to promote positive changes in AIDS prevention. The study included a critical ethnographical analysis in which I conducted focus groups with 15 high- school students about their experiences in receiving AIDS education and interviewed 15 parents and 15 teachers about their experiences in providing the education. To develop participatory knowledge about the current levels and depth of information available in regards to AIDS, I further supplemented the focus group and interview data with a photovoice project with 12 teenage co-researchers, where a more comprehensive look at the issues at stake was taken. As such, the photovoice project enabled the adolescents to articulate their concerns and to propose solutions to the HIV/AIDS crisis by producing photographs, texts, and narratives that depicted their concerns as ‘at-risk youth’ who are advocating for social change. In this thesis, I discuss the implications emerging from this study in depth, with emphasis placed on its key findings: Formal AIDS education is increasingly unpopular and ineffective in Addis Ababa, and AIDS education stakeholders are seeking new ways of teaching about the disease. Subsequently, I propose the adoption of critical pedagogy along with the implementation of new government regulations as viable solutions to improve current AIDS education in Ethiopia.

Keywords: adolescents, critical pedagogy, HIV/AIDS, participatory action research, photovoice.


identifier: Alglawe, Asama  (2018) Design Supply Chain Based on Cost of Quality with Consideration of Quality Level.  PhD thesis, Concordia University.

abstract:
In the contemporary global market, organizations are striving to survive and compete not only by satisfying customer’s needs but also by fulfilling it with the least costs. Quality management experts determined that quality costs account for a substantial part of total production costs. Therefore, finding a way to improve the Quality Level (QL) while minimizing the Cost of Quality (COQ) is a crucial task. In the manufacturing industry, there are a variety of costs that are directly associated with the production; these costs can be considered as visible costs. However, another type of costs may indirectly arise during and after manufacturing processes or even after the product reaches the customer. These types of costs are considered as invisible (hidden) costs and in most cases are difficult to track. Measuring the effect of hidden costs such as the costs of unsatisfying a customer is not straightforward. Even though the hidden costs may have serious consequences for any organization if they are not considered in early stages, they are rarely incorporated in the COQ calculations.
Furthermore, the COQ models found in the literature rarely go beyond the costs incurred within an individual firm and seldom attempt to estimate cost elements related to the customers or suppliers. This, however, does not reflect the reality, since not all the quality costs are generated internally. Suppliers, subcontractors, agents, dealers and customers each contribute (sometimes significantly) to an organization's indirect quality costs. It is therefore proposed to combine the internal measures of COQ with costs related to both upstream and downstream supply chain (SC) partners.
In this thesis, pursuing the aforementioned motivations, we focus on designing SCs in framework of various COQs and QLs. The previous literature lacks a work that integrates the opportunity cost (OC), COQ and QL into SC and Supply Chain Network Design (SCND). The main objectives of this thesis are to consider OC in the COQ analysis, to incorporate it into the Prevention, Appraisal, and Failure (PAF) model, and to analyze it together with various QLs in a manufacturer SC. The purpose is to find an optimum QL that matches the minimum spending on the COQ and. This work proposes a reliable COQ model, which can be used to measure COQ in the whole SC.
We carried out a case study in a manufacturing SC to collect the PAF data and the related data to OC i.e., customer satisfaction. The involved organization is an automobile manufacturing SC. A system dynamics model is used to simulate the COQ, while including OC and analyzing its effects at different QLs.
In addition, PAF, OC, and QL are mathematically modeled in an uncapacitated SC. Different proposed scenarios were developed to allocate the PAF, OC, and QL in the SC. The model determines the best scenario of allocating the COQ at each facility while minimizing the COQ and OC, and thereby optimizing the QL. Based on the COQ, the mathematical model also reveals the difference between the centralized and decentralized SC. Moreover, we address the effects of spending limitations of PA costs on F, OC, and QL at each facility and in the SC as a whole.
Afterwards, the thesis develops a mathematical model which is involved in designing of a capacitated SCND based on PAF, OC, and QL. The developed model is intended to highlight the importance of OC by show the difference between OC-included and OC-excluded SCND model. The SCND model is also used to determine the best improvement in the QL, i.e. the optimal value of investing in the COQ at each echelon.
Finally, a hybrid decision support system (DSS) model which combines the mathematical model and the simulation model for COQ, OC, and QL is developed. The model implements the optimum results of the mathematical model in the simulation model. This aim is to increase spending on PA costs beyond the optimal results of the mathematical model. The model is intended to decrease the OC (increase the number of new customeers). The results show how the combined methodologies can provide better decision support for upper management.
This research shows that COQ can be used as a meaningful measure of improvement not only in an organization but in the whole SC. The methods developed in this thesis will provide a powerful tool to management for assessing quality economics, facilitating quality programs and optimizing benefits of quality across SC.


identifier: Kalantar, Golnar  (2018) Advanced Signal Processing Solutions for Brain-Computer Interfaces: From Theory to Practice.  Masters thesis, Concordia University.

abstract: As the field of Brain-Computer Interfaces (BCI) is rapidly evolving within both academia and industry, the necessity of improving the signal processing module of such systems becomes of significant practical and theoretical importance. Additionally, the employment of Electroencephalography (EEG) headset, which is considered as the best non-invasive modality for collecting brain signals, offers a relatively more user-friendly experience, affordability, and flexibility of design to the developers of a BCI system. Motivated by the aforementioned facts, the thesis investigates several venues through which an EEG-based BCI can more accurately interpret the users' intention. The first part of the thesis is devoted to development of theoretical approaches by which the dimensionality of the collected EEG signals can be reduced with minimum information loss. In this part, two novel frameworks are proposed based on graph signal processing theory, referred to as the GD-BCI and the GDR-BCI, where the geometrical structure of the EEG electrodes are employed to define and configure the underlying graphs. The second part of the thesis is devoted to seeking practical, yet facile-to-implement, solutions to improve the classification accuracy of BCI systems. Finally, in the last part of the thesis, inspired by the recent surge of interest in hybrid BCIs, a novel framework is proposed for cuff-less blood pressure estimation to be further coupled with an EEG-based BCI. Referred to as the WAKE-BPAT, the proposed framework simultaneously processes Electrocardiography (ECG) and Photoplethysmogram (PPG) signals via an adaptive Kalman filtering approach.


identifier: Strantza, Stefania  (2018) International Environmental Agreements - Heterogeneity, Transfers and Issue Linkage.  PhD thesis, Concordia University.

abstract:
This thesis is a study of International Environmental Agreements (IEAs). It examines the formation and stability of self-enforcing IEAs by addressing three important aspects: (i) the impact of heterogeneity among countries on stability, (ii) the effect of transfers among heterogeneous countries on stability (iii) the role issue linkage (environmental and trade policies) can play in enhancing international environmental cooperation.
Chapter 1 investigates IEAs among heterogeneous countries in a two-stage non-cooperative game with quadratic benefit and environmental damage functions and simultaneous choice of emissions. The model is solved analytically, and it is shown that stable agreements cannot be larger with asymmetric than symmetric countries. Their size remains small and their membership depends on the degree of heterogeneity. Moreover, results reveal that introducing asymmetry into a stable, under symmetry, agreement can disturb stability. Therefore, the assumption of homogeneity is not the determining factor driving the pessimistic result of very small agreements.
Chapter 2 is an extension of Chapter 1, implementing policies (transfers) that can increase cooperation incentives among heterogeneous countries. It is shown that in the presence of transfers the size of a stable coalition can be enlarged, due to the contribution of those that are more sensitive to environmental pollution. As the degree of heterogeneity increases, the size of a stable, under transfers, agreement increases as well. However, the analysis demonstrates that reductions in emissions (due to the enlargement of the coalitions) and welfare improvements are rather small, confirming the persistent conclusion in the literature noted as the "paradox of cooperation".
Chapter 3 considers the formation and stability of Global Agreements (GAs). The basic model of the IEAs' literature is extended by letting identical countries choose emission taxes and import tariffs as their policy instruments to manage climate change and control trade. Results illustrate the importance of environmental and trade policies working together to enhance cooperation in effective agreements. Contrary to the IEA model, stable agreements are larger and more efficient in reducing global emissions and improving welfare. Furthermore, the analysis indicates that the size of a stable agreement increases in the number of countries affected by the externalities.


identifier: Luo, Jiaru  (2018) Innovative sludge disinfection approach to generate Class A biosolids for land applications.  Masters thesis, Concordia University.

abstract: Beneficial use of biosolids (sludge), generated by municipal wastewater treatment plant, requires adequate disinfection before its land application. Traditional methods for sludge disinfection are either time consuming or cost demanded. To overcome the drawbacks, novel technologies which uses electrical field phenomena, were proposed to achieve Class A biosolids. Electro-Fenton disinfection and electrokinetics combined with biocide treatment were investigated in this thesis. The lab scale results demonstrated better effectiveness of Electro-Fenton disinfection than Fenton oxidation. Class A quality of biosolids (with 5.8 log reduction) has been achieved within 30 min when Electro-Fenton system was applied in presence of H2O2 (30%). It was found that technological parameters such as pH, current, hydrogen peroxide concentration, total solids content, ratios of Fe2+/H2O2 influenced effectiveness of sludge disinfection. The results showed that electrokinetic phenomena combined with biocide achieved faster disinfection efficiency reaching log 7.2 fecal coliform reduction within 30 to 50 min while the internal temperature rose to 40℃ only. Then, an optimization of current, as well as biocide dosage were conducted in this study. Scale up of the system has also demonstrated an effective sludge disinfection.  The study showed that both systems can be applied to WAS (or potentially to other types of sludge) to convert it to Class A biosolids. The systems are particularly beneficial for sludge thickened with iron containing coagulant. The novel technologies produce fertilizing materials which are safe for environment and public health when landfarming.


identifier: Donkor, Dominic  (2018) How spruce budworm Choristoneura fumiferana detoxify plant host toxins?  Masters thesis, Concordia University.

abstract:
The spruce budworm, Choristoneura fumiferana Clemens (Lepidoptera: Tortricidae), is one of the destructive insect species of the boreal forest in eastern North America. Recent studies have discovered two sets of phenolic compounds that appear to play an important role in the resistance of coniferous trees to the spruce budworm. The phenolic glycosides, picein and pungenin are present in most of the susceptible white spruce trees, but their aglycone forms, piceol and pungenol are found only in white spruce trees resistant to the spruce budworm. These compounds have been shown to retard development time, reduce budworm survival and pupal mass. This research focused on monitoring the fate of these phenolic aglycones (acetophenones) after ingestion by the budworm and aimed at determining how the compounds were detoxified. High performance liquid chromatography-mass spectrometry identified glycosylated and glutathionylated-metabolite of piceol and pungenol in the frass of the caterpillars. Midgut enzyme assays were conducted at neutral and alkaline pH to measure the activity of detoxification enzyme glutathione-S-transferase.
In this study, spruce budworm larvae were reared on either artificial diet only (control diet) or artificial diet containing combined acetophenones (piceol and pungenol). Our results suggest that the insects upregulated production of the detoxifying enzyme, glutathione-S-transferase, in response to feeding on diet containing acetophenones. The acetophenones were thus detoxified by conversion to glycosylated and glutathionylated form in the gut.


identifier: Llewellyn, Anastasia  (2018) Saviour of the Language? The Role and Impact of the Welsh Bible.  Masters thesis, Concordia University.

abstract: Although translation played a critical role in the survival of the Welsh language, Wales has been sorely underrepresented in the field of translation studies. The publication of the 1588 Welsh Bible, the result of a political gamble by Elizabeth I, was a turning point in the survival of the Welsh vernacular. At a time when Welsh was banned from use in public life, the Welsh Bible played a fundamental part in the development of Welsh language and culture. In assessing the cultural, political, and religious reverberations of the Welsh Bible, we espouse an approach similar to those of Delisle and Woodsworth, and Berman, taking into consideration the importance of the socio-political context in which a translation occurs. We touch briefly on Tudor language policy, and its rationale. We examine more specifically the results of Elizabeth I’s decision to prioritize religious uniformity over linguistic uniformity. In affording Welsh-speakers a crucial venue for the use of their own language, Elizabeth inadvertently ensured that Welsh would continue to play a role in daily life in Wales. Owing in no small part to the quality of the translation and the background of the translators, the Welsh Bible, and its ubiquity, were vital in securing the continued existence of the language, through normalization and codification, and, further, were key to redefining the Welsh literary system. Drawing on Jauss’s notion of the horizon of expectation and Toury’s work on polysystem theory, we evaluate the lasting impact of this translation on Wales.


identifier: Wang, Lin  (2018) Stochastic Modelling of Hygrothermal Performance of Highly Insulated Wood Framed Envelopes.  PhD thesis, Concordia University.

abstract:
Wood-framed construction is one of the main building types for residential buildings in North America because of their features such as light-weight, easily built and environmental friendly. However, prolonged exposure to moisture during construction and in service is a durability concern for wood framed envelopes.  As building energy consumption has gained increasing attention in recent years, the majority of building codes in North America require higher insulation levels in building envelopes to improve the building energy efficiency. However, the highly insulated wood framed envelopes may have higher risk of moisture problems such as mold growth and wood decay depending on their configurations. Hygrothermal simulation programs have been widely used for evaluating hygrothermal performance of wood framed envelopes. However, the uncertainties of the input parameters may result in a discrepancy between simulation results and the real performance of the wood framed envelopes, thereafter, unable to reveal the actual risks of moisture problems. Stochastic modelling has been used to investigate the uncertainties of the input parameters and their influence, however, the stochastic parameters were only limited to material properties and boundary conditions in previous studies without considering the moisture loads such as air leakage and rain leakage.

This thesis focuses on developing a methodology to evaluate the hygrothermal performance of wood framed envelopes under various moisture loads using stochastic approach. A stochastic modelling framework is developed based on a well-developed hygrothermal simulation program- DELPHIN and a robust programming platform- MATLAB. Latin Hypercube Sampling technique and Factorial Design Experiment are combined to organize the stochastic material properties, boundary conditions and moisture loads, and generate stochastic models. Uncertainty and sensitivity analysis are performed based on the stochastic input parameters and results to evaluate the moisture content level and mold growth risk, as well as the sensitivity of the moisture performance to each influential factor.

The developed stochastic modelling framework is applied to analyze the hygrothermal performance of Cross Laminated Timber (CLT) wall assemblies and compared with parametric study to demonstrate the advantages of stochastic approach. Then, the hygrothermal performance of the highly insulated wood framed walls (deep cavity walls and exterior insulated walls) are analyzed using the stochastic modelling framework. It is found that the exterior insulated walls have lower mold growth risk than deep cavity walls, and the wall with high permeance exterior insulation (mineral wool) is safer than that with low permeance exterior insulation (polyisocyanurate) in terms of mold growth. The moisture performance of the walls is more sensitive to moisture loads than to material properties, and the significance of the moisture loads (air leakage and rain leakage) depends on climate condition. The thresholds of air leakage rate and rain deposition factor are obtained for the highly insulated wood framed walls to avoid mold growth risk. The design guidelines are formulated for energy efficient and durable wood framed envelopes.  The developed stochastic modelling framework can be also applied to other moisture damage risk analysis such as wood decay and the damage caused by freeze/thaw cycles.


identifier: Jiao, Zhiying  (2018) The Impact of Hurricanes on Different Industries.  Masters thesis, Concordia University.

abstract: In this paper, we investigate impacts on five industries (food, construction, gas and petroleum industry, industry, and transportation industry) from three hurricanes (Katrina, Irene and Sandy) that lead to tremendous economic losses in U.S. history. Our sample consists of 529 public firms from S&P 1500. We find that different industries are affected by hurricanes differently. Hurricanes pose a potential threat to food and insurance industry but could boost gas and petroleum markets and bring benefits to transportation industry if the rise in oil price is not extremely high. Hurricane Katrina, which is the strongest hurricane amongst the three, causes lower effect on the insurance industry than other two hurricanes; and it benefits gas and petroleum industry while other two adversely affect the industry. Furthermore, we notice that, during hurricane period, big companies suffer more than smaller companies. Higher returns on assets and Tobin’s Q are related to higher abnormal returns. Increase in capital expenditures after hurricanes could help companies gain better expectations from investors.


identifier: Wu, Shufei  (2018) Zero-leverage Firms and Their Mergers & Acquisitions.  Masters thesis, Concordia University.

abstract: We examine whether the M&A decisions of zero-leverage (ZL) firms may not be optimal (value-maximizing) as their choices of targets may be limited for maintaining zero leverage, by comparing their short-term announcement returns and long-term post-acquisition firm performance with leverage firms. Our main findings are as follows: debt-free companies tend to acquire targets with low or zero leverage; zero-leverage acquirers underperform non-ZL acquirers around event announcement and the result is robust to using the matched sample and controlling for bidder management quality, governance quality, and bidder, target and deal characteristics; compared to levered buyers, zero-debt buyers display significantly lower long-term post-acquisition operating performance as well as lower post-acquisition stock return performance, and the difference in the long-term operating performance between zero-leverage and leverage bidders is robust to the methodology and benchmark used. Overall, our results show that unlevered firms underperform levered firms during and after the M&A activities. Our results suggest that M&A decisions of zero-leverage acquirers may not be value maximizing since they tend to draw on a limited pool of targets given their preference to maintain zero leverage.


identifier: Gingras, Francois  (2018) A task-based message passing framework.  Masters thesis, Concordia University.

title: A task-based message passing framework

abstract:
Over the past decade, it has become clear that parallel and distributed programming will occupy an increasingly larger proportion of a developer's work. While numerous programming languages and libraries have been built to facilitate working with concurrency, developer work is still difficult and error-prone.

In this thesis, we propose a task-based message passing framework. The proposed framework combines the actor model with message passing functionality to offer a useful and efficient way to implement parallel and distributed algorithms. The framework is intended to be part of a novel C compiler that will offer built-in task and message features. Perhaps most importantly, the new framework aims to be intuitive and efficient.

We have used the framework to implement a parallel sample-sort and a client-server application. Our results demonstrate both strong performance for a parallel sorting algorithm and scalability that extends to thousands of concurrent messages. In addition, we have developed a client server app that emphasizes the intuitive nature of the development cycle for the new model. We conclude that the proposed message passing framework would be well suited to concurrent development environments and offers a simple and efficient way to build applications for the new wave of multi-core hardware platforms.


identifier: Zhou, Yulin  (2018) The Determinants of the Success of Crowdfunding.  Masters thesis, Concordia University.

abstract: Crowdfunding allows the crowd to donate small amounts of money to entrepreneurs through online platforms. Comparing with traditional financial institutions, this new method facilitates the financing process through direct and easy online contact between initiators and investors. Based on the data obtained from Kickstarter, the largest crowdfunding platform, I investigated 27,117 crowdfunding projects from Jan 1st 2015 to Jun 30th 2015, and I find that a crowd funding campaign with a realistic funding goal, a suitable funding period, and more updates and interactions with investors, is much likely to be successfully funded. In addition, the different types of founders are very influential in crowdfunding outcomes. For example, females tend to collect funds more successfully than males do. Founders in the form of teams, companies or a specific project are also beneficial to funding outcomes.


identifier: Gong, Jialu  (2018) The Effect of Nuclear Disasters on Energy Futures Markets.  Masters thesis, Concordia University.

abstract: In my thesis, I aim to examine the effect of nuclear disasters on energy futures markets. I use the crude oil and the heating oil futures contracts, which are the two most actively traded energy futures contracts, as representatives of this market. The nuclear disasters are classified into three categories, the incident-level category, which includes events rated level 1 to level 3, the accident-level category, which includes events rated level 4 to level 7 and the total category, which includes both incident-level and accident level events. In my thesis, I address the effect of all three categories of nuclear events upon both crude oil futures and heating oil futures contracts, to determine whether the nuclear events affect the energy futures market and if so, whether the impacts are related to the severity of the nuclear disasters. For both contracts, I use the market model with Generalized Autoregressive Conditional Heteroskedastic (GARCH) effects to estimate the distribution of returns in the estimation period which includes no nuclear disasters. The results show that for both contracts, the accident-level category of events are associated with statistically significant negative impacts for almost each day in the event window and post-event window. However, for the incident-level and the total category of events, the cumulative average abnormal returns are only statistically significant negative for the first 2 days following the event day and the last 10 days in the post-event window. The cumulative average abnormal returns show that only the accident-level category has a persistent impact upon the futures contracts beyond the event date. I also find that the heating oil futures contract adjusts faster to information about the nuclear disaster, since during the post-event window, the cumulative average abnormal returns revert to a zero mean.


identifier: Safdari, Mohammad Javad  (2018) Design, analysis, and optimization of photonic crystal Sensors.  Masters thesis, Concordia University.

abstract: It has been more than 30 years that Photonic Crystal (PhC) have been used in wide variety of applications. The photonic bandgap phenomenon and the flexibility of such structures to manipulate the light have made them popular. PhC sensors are popular because of their promising characteristics like high measurement sensitivity, ultra-compact size, suitability for monolithic integration, and flexibility in structural design. In this thesis, a novel framework for designing optimized PhC sensors has been proposed. The complexity of such structures resulted in the lack of an analytical method to design the structures. Therefore, this framework aims to provide a comprehensive and automatic method to find the best values for the structural parameters without human involvement. The framework is explained with an example of designing a PhC liquid sensor. In the framework, an optimizer called Multi-Objective Gray Wolf Optimizer is utilized. However, a diverse range of multi-objective optimizer algorithms could be utilized. The results show that the proposed framework can design any kind of PhC sensor. Simplicity, being straightforward, and no human involvement are the advantages of the proposed framework. In addition, a significantly wide range of optimal designs will be found which are suitable for general and specific applications.


identifier: Wallman, Heather  (2018) Thirty Days in a British Columbia Transition House: Feminist Governance on the Frontline of the Settler-State.  Masters thesis, Concordia University.

abstract: The goal of this thesis is to elucidate how British Columbia transition houses function through the intersection of the Canadian neoliberal economy and settler-state: do transition houses become an indirect branch of the welfare system that contributes to a Canadian settler-state? Between 2016-2017, approximately seventy percent of women who used Lake House services identified as First Nations, according to demographic statistics we gather during intake. Therefore, I argue that BC transition houses not only give an impression that a neoliberal government is trying to ameliorate violence against women, transition houses play a part in sustaining a settler-state through its policies, protocols and paperwork that co-terminously create and monitor subjects who bolster the neoliberal class divide. Transition houses (in their best intentions) continue to reproduce marginalized subjects whose scarce economic “rights” allow the new neoliberal class, one that is formed by “restrict[ing] in favour of the freedoms of the few” (Harvey 2005: 70), to maintain hegemony through property and land ownership. Consequently, residents of the transition house are left with few housing options: monitored social housing, an unaffordable BC housing market or returning to an abusive situation. Through autoethnography, I plan to unpack my argument from the position of the transition house worker in relation to a woman calling the crisis line (the point of first contact) to her outtake (exit out of the house), parsing the development of “our” (the workers) relationship with her through our policies, protocols and paperwork. Furthermore, I ask the following question about the role of workers in Canadian NGOs: Are we on the frontlines of change or protecting the settler-state?


identifier: Honarmand, Fatemeh  (2018) Cinema and the Production of Spatial Memories: Fifty Years of Representing 1960s Montreal in Quebecois Films.  Masters thesis, Concordia University.

abstract:
Since the end of the 20th century, cinema has been widely recognized as a meaningful source of information for studying geographic phenomena including urban development. This thesis aims to further explore the potential of cinema to produce our spatial memories. The research question that structures this project is: how does the cinematographic representation of a certain place during a certain period evolve over time? This question is addressed through the study of the cinematographic representation of 1960s Montreal over time. Seven films released between 1964 and 2014 (Le chat dans le sac (1964), Entre la mer et l’eau douce (1967), Yesterday (1981), Emporte-Moi (1999), Monica la mitraille (2004), C.R.A.Z.Y. (2005), Corbo (2014)) were selected for study since they can all be identified as unfolding in Montreal of the 1960s. Each of these films have then been evaluated according to four main criteria: politics, religion, urban mobility and urban development.
This analysis first shows only a marginal interest in Québec cinema of the last 50 years for revisiting the Quiet Revolution despite the importance of this period in modern Québec history. Nevertheless, all seven of the films identified but one (i.e. C.R.A.Z.Y.) directly address the political tensions that were at stake during this period. Religion was the second-most common theme identified in these movies. Even though it was not as prevalent as politics, religious issues recurred throughout all the movies studied.
The other two topics under study appeared more marginally in the selected movies, although some trends began to emerge from the study. For instance, the action of the movies released after 2000 took place in the suburbs of Montréal, while the earlier movies barely ventured beyond the downtown core, illustrating the growing importance given to the development of the suburban in recent decades. This centrifugal movement was not accompanied with a change of transportation since cars remained the main way of transportation throughout the seven studied movies.
Overall this project did not identify radical changes in the way the cinematographic representation of Montréal of the 1960s has evolved over the last fifty years, but it contributed to the development of a methodology dedicated to further examining how cinema participates in the reshaping of our collective spatial memories.


identifier: Quintana Zunino, Gonzalo Renato  (2018) The Role of Brain Opioid Transmission in the Conditioned Ejaculatory Preference of the Male Rat.  PhD thesis, Concordia University.

abstract: The experiments presented in this thesis examined the role of opioids in sexual pleasure, particularly during early formative sexual experiences, on the ability of male rats to associate an olfactory or somatosensory cue with their ejaculation-induced sexual reward state. The results show that opioids are an important substrate of the sexual reward state, and that this state feeds forward to form a conditioned ejaculatory preference (CEP), in which male rats ejaculate preferentially with females bearing or wearing the cue associated with sexual reward. This suggests that sexual reward (a presumably “proximate” cause of behavior) lies at the root of monogamous mate choice in the rat. These data also contribute to a growing body of evidence that the species’ specific sexual strategies of the male rat, often described as promiscuous, evidence a degree of plasticity that can move toward a monogamous mate choice when features of a familiar female (odor or jacket) are associated with sexual pleasure. This conditioned ejaculatory preference for familiar cues suggests that proximate pleasure-related states act as a Pavlovian US that can reinforce cue-related CSs to create partner and mate preferences. Such preferences bring proximate reward states into synch with reproductive choice, potentially enhancing reproductive success. Findings are discussed, as well as further directions.


identifier: Abu-Lebdeh, Mohammad  (2018) NFV Management and Orchestration in Large-Scale Distributed Systems.  PhD thesis, Concordia University.

abstract:
Network Functions Virtualization (NFV) radically transforms the way network operators design and manage network services, promising a lot of potential benefits such as agility, flexibility, reduction of CAPEX and OPEX. It eliminates the dependency between the network function software and hardware enabling pure-software based network function that runs on commodity hardware, called Virtualized Network Function (VNF). NFV, along with other emerging technologies such as Software-Defined Networking (SDN), enables network operators to create dynamic and programmable network services, wherein VNFs are deployed on-demand, dynamically chained and optimized over time to cope with emerging business needs. The European Telecommunications Standards Institute (ETSI) developed the NFV Management and Orchestration (MANO) framework, which consists of Virtualized Infrastructure Manager (VIM), VNF Manager (VNFM) and NFV Orchestrator (NFVO), in order to provide network operators with the sophisticated capabilities needed to manage the dynamic aspects of infrastructure, VNFs and network services.

This thesis elaborates and addresses key architectural and algorithmic research challenges related to the NFV management and orchestration in distributed and large-scale systems. We look at orchestration scalability from an architectural perspective and propose to leverage two-layer hierarchical service orchestration to manage network services over distributed infrastructure. We also propose an architecture of Virtual Network Platform-as-a-Service (VNPaaS) that utilizes the hierarchical orchestration to offer next-generation mobile networks as-a-service. The architecture is illustrated by offering the 3GPP Home Subscriber Server (HSS) as-a-Service (HSSaaS), in which the HSS is decomposed into VNFs with a granularity finer than what is known today. On the algorithmic side, a key challenge is to identify the number and location of the NFVO and VNFM functional blocks since they have a significant impact on the overall system cost and performance, among others. In particular, we tackle the online placement of VNFM to enable network operators to adjust the number and location of VNFMs in response to variation in workload. There, we assume a fixed location of NFVO and aim at minimizing the operational cost. Owing to its complexity, we propose a tabu search heuristic and numerically show that it is faster than the mathematical formulation by many orders of magnitude. We further study the joint placement of NFVO and VNFM. We first address the problem in the context of the multi-orchestrator system and seek to minimize the number of NFVOs and VNFMs. We mathematically formulate the problem and propose a two-step placement heuristic to solve the problem efficiently. Finally, we investigate the same problem in the context of single- and multi-orchestrator systems providing a comparative study of the worst-case delay in both scenarios. We also propose a late acceptance hill-climbing heuristic to solve the problem in a reasonable time frame.


identifier: DJEDDI, TAREK  (2018) Digitally Controlled Microwave Components for High-Power Radar System.  Masters thesis, Concordia University.

abstract:
Radar Systems are among the most widely used communication systems. They are used in both military and civilian applications such as: Remote sensing, Microwave Sounder (MWR), Ship Navigation, and Air Traffic Control (ATC). Radar systems use high power electromagnetic signals to detect and locate faraway objects such as aircrafts or ships. The development of radar started in the 1930s, before and during the Second World War, however it is still an important area of research with its critical role in various applications.
Typically, radar systems require high-power to cover large areas. Such high power cannot be derived from one source. Therefore, multiple power sources are combined together to achieve such high power, where these sources must be synchronized and in-phase. In the normal operation of a traditional power combining network, the internal matching of the network is the most important design factor, so that the power sources will be combined without any significant losses. However, in case of failure of any source before the combining stage, the power of the working sources will be reflected and dissipated into a protection circuit causing huge losses and degradation in the overall system performance.
In theory, it is impossible for any three-port passive networks (such as power combiners) to satisfy three conditions: losslesssness, internal matching, and the reciprocity. The power combining is usually made out of conducting linear material to satisfy both the reciprocity and the losslessness conditions. Hence, the failure of one source at the combiner port leads to reflection as the network theoretically cannot be internally matched. To overcome this limitation, the power combining system must deploy active components to avoid the mismatch situations.
In this thesis, we propose a system which improves the performance of power combining networks by detecting the failure events of the malfunctioning source and directs the properly-functioning source to the output by the aid of electrically controlled switches. The proposed system uses directional couplers to extract a power sample from the signal passing through each branch. We build and test the controlling subsystem where all the required elements are integrated up to the proposed design. Moreover, we propose a novel Band-Pass Filter (BPF) structure using coupled structure resonators to reject the out band and reduce the noise power as a pre-filtering stage to the energy detection. Also, energy detection technique is used to identify which power source is still in operation. Finally, we provide closed-form mathematical expressions for the performance of the proposed energy detector in terms of the probability of false alarm and detection.


identifier: Glassman, Daniel Didier  (2018) Yours to Carry: A Collection of Short Stories.  Masters thesis, Concordia University.

abstract: The protagonists in the stories of this collection of short fiction confront variations of the same existential question: How—if at all—are we to carry our life’s burdens? Can we unburden ourselves of them? If so, at what cost? What role do those with whom we share our lives play in the carrying of these burdens with us? The title, Yours to Carry, echoes this theme and is overtly explored in the last two stories of the collection. At the same time, as a work of literary fiction, the title suggests to readers that something—namely, the book they now hold in their hands—has been unburdened upon them by the author. The reader may choose to pick it up—or not—but is given the terms of the exchange at the outset.


identifier: Qiao, Jing  (2018) Trajectory Tracking and Payload Dropping of an Unmanned Quadrotor Helicopter Based on GS-PID and Backstepping Control.  Masters thesis, Concordia University.

abstract:
Two useful control techniques, the Gain-Scheduled Proportional-Integral-Derivative (GS-PID) control and backstepping control, have been applied by using quadrotor Unmanned Aerial Vehicle (UAV) in the applications of trajectory tracking and payload dropping operations in this thesis. These control algorithms are analyzed and verified through software simulations and experimental tests.
The dynamic model of the quadrotor UAV is firstly established using Newton-Euler laws. The quadrotor comes with a symmetric, nonlinear and multiple-input-multiple output (MIMO) dynamic model.
The GS-PID control algorithm is implemented firstly in take-off, trajectory tracking, payload dropping, and landing periods of flight in trajectory tracking and payload dropping scenarios.
Unlike other control algorithms that tend to linearize nonlinear systems, backstepping works without cancelling the nonlinearities in the system. This leads to more flexible designs of the control model. The backstepping control is implemented in this thesis for better performance of the quadrotor UAV for the two scenarios as well. Both control algorithms are implemented on the parameters of an unmanned quadrotor helicopter platform known as Qball-X4 available at the Networked Autonomous Vehicles Lab (NAVL) of Concordia University.
Using MATLAB/Simulink to build the simulation control model, the flight simulation of the Qball-X4 is carried out for the trajectory tracking and the payload dropping. In order to further investigate these two control approaches, the Qball-X4 is used for experimental verification on payload dropping performance. The results indicate that both algorithms can obtain acceptable performance, but the backstepping controller proves to be a better performed one.


identifier: Yang, Senwen  (2018) Wind Effects on Air Curtain Aerodynamics Performance.  Masters thesis, Concordia University.

abstract: Air curtains are widely used in various building types to reduce infiltration and associated energy losses through building entrances. Quantifying the infiltration rate through a building entrance is directly related to the evaluation of the energy performance of air curtains. Consequently, many previous studies identify and measure the impacts of various factors on performance, including door operation, usage frequency and air supply angle and velocity. However, to date limited studies have focused on the effect of wind on air curtain performance, even though wind is commonly considered to play an important role. The purpose of this research is to identify wind effects on the performance of air curtains through an experimental study, taking into account parameters including wind speed and angle, air curtain supply flow speed and supply flow angle, and the pressure difference acting across an air curtain. The relation between air infiltration and the pressure difference across an air curtain with and without wind is analyzed. Experiments are conducted in a large chamber equipped with an air curtain and a corresponding sub-scaled model in the wind tunnel. The results from differing wind speeds and air curtain supplies from both experiments are subsequently compared, and the wind effects in both cases are found to be consistent. This study finds the following: when the air curtain jet is able to reach the floor, thus providing a good sealing of the door, it can effectively resist the wind; a strong wind blowing directly towards the air curtain reduces its performance; and the performance is related to both wind speed and wind incident angle.


identifier: Maeda, Rie  (2018) Problems Filipino caregivers continue to face after the abolishment of the Live-in Caregiver Program in Canada.  Masters thesis, Concordia University.

abstract:
Feminists have long argued that the current economic system, especially the standards of national economic accounting, are structured by men in a manner such that they can dominate women, or at least, keep women in ‘their place.’ The truthfulness of such accounts is nowhere more evident than in the case of Filipino caregivers.
Since national economic accounting systems do not recognize the economic value of time women spend in household services or caregiving activities, female labour invested in such caregiving is excluded from both sides of national income, and from product accounts. This means the current economic system has important consequences for women in both the developed and developing world. This system encourages women in the developed world to seek employment outside the house to be considered a productive and contributing member of national economy. However, women in the ¬developed world cannot completely escape childcare and other caregiving responsibilities, hence they employ the labour of women from the developing world. The Filipino story in this thesis is situated within this context. The act of caregiving or raising children within the current neoliberal economy has been turned into a commodity. Like any other commodity, it can be brought when needed and disposed of when not needed anymore.
This thesis is focused on Canada’s policies concerning caregivers in recent years, as well as the occupational and social mobility of these caregivers who became permanent residents through the Live-in Caregiver Program. This thesis also looks at the educational levels of these Filipino caregiver workers upon their arrival, and the type of news or opportunities Canada makes available for them to enhance their education once they become permanent residents of Canada.
In this thesis, I use standpoint theory both as a conceptual framework and a methodology. By interviewing and obtaining narrative accounts of six participants who came from the Philippines, this thesis reveals the difficulties they faced during the life in the Live-in Caregiver Program and the challenges they continue to have after becoming permanent residents.


identifier: Alharthi, Yasir Mohammed  (2018) Shaft Resistance of Driven Piles in Overconsolidated Cohesionless Soils.  PhD thesis, Concordia University.

abstract:
Piles are structural members that transfer the applied load of superstructures to deep supportive layers of soil or bedrock. Besides controlling the settlement of structures, piles provide sufficient capacity that other foundations cannot provide or provide only at a high cost. Despite ample research on the shaft resistance of displacement piles in cohesionless soils, the mechanism of such resistance remains unclear. Consequently, theories on shaft resistance have generated several discrepancies in predicting the capacity of displacement piles in cohesionless soils, not only due to the complexity of modeling cohesionless materials and collecting field data but also because the role of overconsolidation in such soils, which is often neglected. Although the critical depth of pile foundation in cohesionless soils has long been debated, definite conclusions have yet to be drawn.
     Overconsolidation in cohesionless soils directly affects the lateral earth pressure that acts upon the pile shafts and thus upon pile capacity. Overconsolidation can occur naturally or artificially when the ground surface is subjected to erosion, excavation, or unloading, often due to glacial melting, the demolition of structures, raised water tables, compaction, or vibration.
     This thesis presents an experimental investigation into the capacity of driven piles in overconsolidated cohesionless soils. Tests, with an emphasis on the shaft resistance and the critical depth, were conducted on long piles in a setup that permits measuring the overconsolidation ratio in the test tank as well as the total and local shaft resistance on the pile’s shaft. Shear stress distribution along the pile’s shaft showed some dependency on embedment depth ratio (L / D). Also, critical depth was observed for shaft resistance only when mean shaft resistance was analyzed, and was in line with Meyerhof’s (1976) results.
     An analytical model was also developed based on limit equilibrium analysis using the horizontal slice method to predict the shaft resistance of a pile driven into normally consolidated cohesionless soils. The model assumes an inclined failure surface around the pile that accounts for the shear and normal stresses upon it. Critical depth was not only observed but also increased linearly as the angle of shearing resistance increased. A three-dimensional numerical model was developed and validated experimentally to perform 200 pile load tests in soils with various densities and at a range of embedment depths.
     Design theories to predict the shaft resistance of displacement piles in cohesionless soils and the critical depth were developed, design charts are presented.


identifier: Alam, Mohammad Nazmul  (2018) An Architecture for an Infrastructure as a Service for the Internet of Things.  Masters thesis, Concordia University.

abstract:
Internet of things (IoT) refers to things such as sensors and actuators interacting with each other to reach common goals. It enables multiple applications in sectors ranging from agriculture to health. Nowadays, applications and IoT infrastructure are tightly coupled and this may lead to the deployment of redundant IoT infrastructures, thus, cost inefficiency.

Cloud computing can help in tackling the problem. It is a paradigm to quickly
provision configured resources (computing, network, memory) on demand for cost efficiency. It has three layers, the infrastructure as a service (IaaS), the platform as a service (PaaS) and the software as a service (SaaS). Through the IaaS, configured hardware resources (CPU, storage, etc.) are provisioned on demand. However, designing and implementing an IoT IaaS architecture for the provisioning of IoT resource on demand remains very challenging. An example of a challenge is using the appropriate publishing and discovery mechanism suitable for IoT devices. Orchestrating a virtualized IoT device over several physical IoT devices is another challenge that needs to be addressed.

The main contribution of this thesis is twofold. First, a novel IoT IaaS architecture is proposed where IoT devices can be provisioned as a configured infrastructure resource on demand via node virtualization. Second, the architecture is prototyped and evaluated using real-life sensors that support node virtualization. Node level virtualization achieves resource efficiency in contrast to middleware solutions. The essential architectural features, such as publication, discovery, and orchestration are identified and proposed. Two sets of a high-level interface are also introduced. A low-level uniform interface is suggested to decouple the IoT devices from the applications by allowing the applications to access the heterogeneous devices in a uniform way. In addition, a cloud management interface is proposed to expose the IoT IaaS to the cloud consumers (for example - the PaaS, the application, etc.) and allow them to provision the IoT resources.

By allowing the capability sharing of the IoT devices using the node virtualization, the cost efficiency and energy efficiency are achieved in the proposed architecture. Addressing other challenges allowed the proposed architecture to expose the IoT devices to the IaaS in a more abstract manner. Thus allowing the application to provision the IoT resources on demand as well as handling the IoT device heterogeneity in the IaaS.


identifier: Guo, Liang  (2018) Labor Market Impacts of School Interruptions: A Dynamic, Structural Approach.  PhD thesis, Concordia University.

abstract: Schooling interruptions are common in North America and have recently attracted the attention of economists. In this paper, I provide structural estimates of a dynamic model of education and labor supply to investigate the impact of schooling interruptions on subsequent wage and employment outcomes. In this model, schooling interruptions evolve endogenously, and I approximate the expected value function using an approach suggested by Geweke and Keane (1996) that significantly reduces computational time. The results indicate that a temporary interruption to schooling attainment hurts post-graduation income relative to continuous investment in education, and consequently on the life-cycle income. However, even with an interruption, there are still significant wage gains from college and university relative to high school. Finally, the costs of interruptions and wage gains are heterogeneous and vary significantly across different racial groups and types of agents at both waves of NLSY. Using policy simulation, I find that under a post-secondary schooling subsidy policy, up to 4 percent more white males from cohort 1979 will make a choice to return to school, 9.6 percent more of them will obtain a university-level degree, and the hourly wage will also increase up to 4.1 percent. Under the same post-secondary schooling subsidy policy simulation, the white males from the 1997 cohort been more affected by the subsidy than their earlier cohort. At each cohort, black and Hispanics are more affected by the policy.