identifier: Monette, Cassandra  (2016) I-Click Photography: An Exploration of Student Perspectives on Learning and Engagement.  Masters thesis, Concordia University.

abstract:
As has been seen in previous research, school engagement is a necessary factor in student success (Al-Hendawi, 2012; Baker, Derrer, Davis, Dinklage-Travis, & Linder, 2001; Boyle & Lipman, 2002; Covell, 2009; Gamoran, 1992; Simons-Morton & Chen, 2009; Willms, 1999a; Wolfe & Mash, 2006). However, students with emotional and/or behavioural difficulties tend to have lower rates of academic success and school completion (Wagner et al., 2003; Kauffman, 2008; Ryan, Pierce, & Mooney, 2008).  Shedding light on how these students perceive their learning environments can help to facilitate the development of effective prevention and intervention programs that seek to promote success for all learners.
This research study aims to explore students’ perspectives on their learning environments at school, through the use of participatory action research (PAR). In collaboration with the teachers and parents, a photography project took place at an elementary school in the Montreal area in Canada. Seven elementary students from grade one to grade six, who had been identified as having socio-emotional difficulties participated and took photographs of what was most important to them about learning at school. Students were interviewed about their photographs and were then invited to share their stories and photographs with their teachers, parents, and peers through a final closing photo exhibition. Teacher focus groups were also conducted in order to understand how these students’ environments may play a role in their learning.
Using grounded theory to guide this qualitative analysis of the students’ visual storytelling narratives, we explored emerging themes and patterns from these narratives to understand student perceptions.  Interestingly, consistent with other research pointing to the importance of family-school collaboration, students’ perspectives of their school environment seems to always be coupled with how it relates to their home lives. Secondly, although this study discussed learning and engagement, student narratives seem to focus more on social relationships as highly influential in their school life; the students did not seem to include much on academic engagement. Finally case study summaries using focus group discussions and field notes reveal the strengths and challenges that each child was perceived to have, as well as how each child engaged with the methodology of using photography as a tool to express various needs and wants.
Overall it seems that the findings may suggest that these students put other forms of learning and engagement at the forefront of their school experience. With this understanding, a supportive environment can be created for these students and adapted to their perceptions of engagement in school. Final discussions include reflections on the methodology as a school engagement activity.


identifier: Lussier-Craig, Alexandra  (2015) Googling Art: museum collections in the Google Art Project.  Masters thesis, Concordia University.

type: Thesis NonPeerReviewed

abstract: This thesis examines the Google Art Project, a division of Google that gathers and curates digital reproductions of museum and gallery holdings. Using the collections of the McCord Museum and Royal Ontario Museum to focus the discussion, I examine the Art Project's practices of collection. Drawing on scholarship in museum and archive studies, digital media and software studies, as well as on the theoretical work of Michel Foucault on the archive and the heterotopia, I argue that the Art Project occupies the positions of hybrid and heterotopia. From this position, I examine the ways that the Art Project re-orders and interprets the items it collects.


identifier: Roy, Sujan Kumar  (2016) Single Channel Speech Enhancement using Kalman Filter.  Masters thesis, Concordia University.

abstract:
The quality and intelligibility of speech conversation are generally degraded by the
surrounding noises. The main objective of speech enhancement (SE) is to eliminate
or reduce such disturbing noises from the degraded speech. Various SE methods have
been proposed in literature. Among them, the Kalman filter (KF) is known to be an
efficient SE method that uses the minimum mean square error (MMSE). However,
most of the conventional KF based speech enhancement methods need access to clean
speech and additive noise information for the state-space model parameters, namely,
the linear prediction coefficients (LPCs) and the additive noise variance estimation,
which is impractical in the sense that in practice, we can access only the noisy speech.
Moreover, it is quite difficult to estimate these model parameters efficiently in the
presence of adverse environmental noises. Therefore, the main focus of this thesis is to
develop single channel speech enhancement algorithms using Kalman filter, where the
model parameters are estimated in noisy conditions. Depending on these parameter
estimation techniques, the proposed SE methods are classified into three approaches
based on non-iterative, iterative, and sub-band iterative KF.
In the first approach, a non-iterative Kalman filter based speech enhancement
algorithm is presented, which operates on a frame-by-frame basis. In this proposed
method, the state-space model parameters, namely, the LPCs and noise variance, are
estimated first in noisy conditions. For LPC estimation, a combined speech smoothing
and autocorrelation method is employed. A new method based on a lower-order
truncated Taylor series approximation of the noisy speech along with a difference
operation serving as high-pass filtering is introduced for the noise variance estimation.
The non-iterative Kalman filter is then implemented with these estimated parameters
effectively.
In order to enhance the SE performance as well as parameter estimation accuracy
in noisy conditions, an iterative Kalman filter based single channel SE method is
proposed as the second approach, which also operates on a frame-by-frame basis.
For each frame, the state-space model parameters of the KF are estimated through
an iterative procedure. The Kalman filtering iteration is first applied to each noisy
speech frame, reducing the noise component to a certain degree. At the end of this
first iteration, the LPCs and other state-space model parameters are re-estimated
using the processed speech frame and the Kalman filtering is repeated for the same
processed frame. This iteration continues till the KF converges or a maximum number
of iterations is reached, giving further enhanced speech frame. The same procedure
will repeat for the following frames until the last noisy speech frame being processed.
For further improving the speech enhancement performance, a sub-band iterative
Kalman filter based SE method is also proposed as the third approach. A wavelet
filter-bank is first used to decompose the noisy speech into a number of sub-bands.
To achieve the best trade-off among the noise reduction, speech intelligibility and
computational complexity, a partial reconstruction scheme based on consecutive mean
squared error (CMSE) is proposed to synthesize the low-frequency (LF) and highfrequency (HF) sub-bands such that the iterative KF is employed only to the partially
reconstructed HF sub-band speech. Finally, the enhanced HF sub-band speech is
combined with the partially reconstructed LF sub-band speech to reconstruct the
full-band enhanced speech.
Experimental results have shown that the proposed KF based SE methods are
capable of reducing adverse environmental noises for a wide range of input SNRs,
and the overall performance of the proposed methods in terms of different evaluation
metrics is superior to some existing state-of-the art SE methods.


identifier: Marey, Omar Ibrahim  (2016) A Framework for Argumentation-Based Agent Negotiation in Uncertain Settings.  PhD thesis, Concordia University.

abstract:
Automated negotiation technologies are being increasingly used in business applications, especially in the e-Commerce domain. Argumentation-Based Negotiation (ABN), among the existing approaches, has been distinguished as a powerful approach to automated negotiation due to its ability to provide more sophisticated information (arguments) that justifies and supports agents’ proposals in order to mutually influence their preference relations on the set of offers, and consequently on the negotiation outcome. During the recent years, argumentation-based negotiation has received a considerable attention in the area of agent communication. However, current proposals are mostly concerned with presenting protocols for showing how agents can interact with each other, and how arguments and offers can be generated, evaluated and exchanged under the assumption of certainty. Therefore, none of these proposals is directly targeting the agents’ uncertainty about the selection of their moves nor designing the appropriate negotiation strategies based on this uncertainty in order to help the negotiating agents better make their decisions in the negotiation settings where agents have limited or uncertain information, precluding them from making optimal individual decisions. In this thesis, we tackle the aforementioned problems by advocating an Argumentation-Based Agent Negotiation (ABAN) framework that is capable of handling the problem of agents’ uncertainty during the negotiation process.
    We begin by proposing an argumentation framework enriched with a new element called agent’s uncertainty as an important parameter in the agent theory to allow negotiating agents to decide which moves to play and reason about the selection of these moves under the assumption of uncertainty. Then, a method for agents’ uncertainty assessment is presented. In particular, we use Shannon entropy to assess agent’s uncertainty about their moves at each dialogue step as well as for the whole dialogue. Negotiation strategies and agent profiles issues are also explored and a methodology for designing novel negotiation strategies and agent profiles under the assumption of uncertainty is developed. Moreover, two important outcome properties namely, completeness and Nash equilibrium are discussed. Finally, the applicability of our framework is explored through several scenarios of the well-known Buyer/Seller case study. The obtained empirical results confirm the effectiveness of using our uncertainty-aware techniques and demonstrate the usefulness of using such techniques in argumentation-based negotiations.


identifier: Song, Shibo  (2016) Location Models for Two Different Applications.  Masters thesis, Concordia University.

abstract:
There has been a growing interest in location problems for their wide use in many
areas, such as passive optical networks and logistics networks. However, as the
papers appear in different literature, researchers usually do not take advantage
of their mutual findings. We propose to bridge the gaps and therefore to propose
efficient solutions schemes for two different applications.

In the first application, our research goal is to investigate the FTTX (Fiber-to-the
Home/Premises/Curb) passive optical network (PON) for the deployment of broadband
access. We focus on designing the best possible architectures of FTTX hybrid PONs,
which embraces both Time Division Multiplexing (TDM) and Wave Division
Multiplexing (WDM) technology. A hybrid PON architecture is very efficient as it
is not limited to any specific PON technology, rather it is flexible enough to deploy
TDM/WDM technology depending on the type (i.e., unicast/multicast) and amount
of traffic demand of the end-users. We investigate the optimized covering of a geographical
area by a set of cost-effective hybrid PONs. We propose a novel network design
optimization scheme for greenfield deployment of a set of hybrid PONs, in which all
significant constraints are taken into account, e.g., type of traffic, attenuation, choice of
splitting equipment.

In the second application, we revisit the p-center location problem in the context of
disruption events. We propose an optimized covering in the geographical area for a
given number of customers and suppliers, ensuring each customer is assigned a
primary supplier and a different backup supplier unless the primary supplier has a
so-called fortified facility. However, the budget for facility fortification is limited and
only few facilities can be fortified. We design an optimization model under the assumption
of single event disruptions, and estimate accurately the required facility capacities while
taking into account a sharing of the backup resources.

We evaluate our proposed models and algorithms by a comprehensive set of numerical
experiments, with some comparisons in each of these two applications. Conclusions are
drawn in the last chapter.


identifier: Abedi, Najmeh  (2015) Development of a sustainable process to reduce CO2 emissions using anaerobic treatment of industrial pulp and paper wastewater.  PhD thesis, Concordia University.

abstract:
Atmospheric concentration of carbon dioxide (CO2), a major component of greenhouse gases, has increased significantly since the beginning of the industrial revolution. Many attempts have been aimed at capturing, sequestering, and reducing carbon dioxide emissions, but they have not been very efficient and economical.
The objective of this work is to develop a sustainable system to reduce the carbon dioxide emissions by applying anaerobic treatment of wastewater. In this method, industrial emissions containing CO2 are injected into a wastewater stream entering the anaerobic reactor where CO2 is biologically converted to methane as a biogas. This conversion is based on the final step of anaerobic degradation in which methanogenic bacteria produce methane from acetic acid or CO2 and hydrogen. Consequently, with the addition of carbon dioxide after wastewater pollutant degradation (that provides acetic acid and hydrogen), methane with a high efficiency can be produced through a highly sustainable process.
To investigate the feasibility of this process for CO2 removal, two series of batch tests using the Chemi-Thermomechanical Pulping (CTMP) and recycled pulp and paper wastewater were performed. In this project pulp and paper wastewater was selected since this industry produces a large amount of wastewater and is responsible for a large portion of CO2 emissions. In order to determine the optimal conditions, the effect of different parameters such as pH (5.5 - 7.5), and temperature (30 - 35ºC) on the efficiency of CO2 and COD removal and methane production was investigated.
As a conclusion of the first part of this work, it was shown that anaerobic treatment can be used to remove carbon dioxide by bioconversion to methane. By applying this method, CO2 concentration will be reduced and methane will be produced simultaneously. The results show that at all pH values examined in the present work, CO2 removal by bioconversion into methane is higher in samples with CO2 injection compared to the control samples with no CO2 injection. Results also showed that CO2 removal was higher at lower pH values. For example, for CTMP wastewater at pH 7.5 and 35°C the CO2 removal by bioconversion into methane in samples with CO2 injection was 13 mg/l (19%) higher than the control sample, while this value at pH 5.5 was 515 mg/l (29%) higher than the control sample. At 35°C and at all pH values, the increase in CO2 removal by bioconversion to methane in samples with CO2 injection compared to the control samples with no CO2 injection was 3-6% higher than that obtained at 30°C. The best efficiency for CO2 removal occurred at pH 5.5 and 35ºC.
Operating pH and temperature and injection of CO2 didn’t show significant impact on COD removal, although higher COD reduction rates were achieved at higher temperature. It was shown that COD reduction rates were almost similar at different pH values. Temperature has a significant impact on methane generation at all operating pH. Injection of carbon dioxide had a positive impact on methane production and in samples with CO2 injection more methane generation was observed.
Although at higher pH values methane generation is higher than that at lower pH values, the increase in methane generation by the injection of CO2 to the wastewater is lower. The reason for this observation is that at a higher pH of 7 and 7.5, only a small amount of CO2 was dissolved in the wastewater and was later converted to methane. Therefore, at higher pH values, the difference in methane generation in the presence and absence of CO2 injection was less than that observed at lower pH values.
In CTMP wastewater at 35ºC, the injection of CO2 into the wastewater increased methane generation by 162 ml (108%) at pH 5.5 and by 22 ml (3%) at pH 7.5. For the recycled paper experiment at 35ºC, the injection of CO2 into the wastewater increased methane generation by 54 ml (93%) at pH 5.5 and by 8 ml (4%) at pH 7.5.
The continuous experiments were performed following the batch tests in the UASB reactors at three organic loading rates (OLR of 1, 2, and 3g COD/l.d.) using CTMP wastewater for 115 days. Results showed that regardless of CO2 injection and initial pH of wastewater, COD removal was almost equal from the reactor with CO2 injection in the feed (R2) and control reactors (R1). The COD removal, equal to 70% was achieved at OLR=1 g COD/l.d, and its value gradually decreased to 65% at OLR=3g COD/l.d.
Methane generation in R2 with CO2 injection was higher than the control reactor with the same pH (pH 5.5) in its influent wastewater. However these values were less than the methane generation in the control reactor without pH adjustment (with influent wastewater of pH 6.5) that was more suitable for methanogenic activity. Methane generation in R2 at OLR 1, 2 and 3 was approximately equal to 400-570, 960-1120, and 700-1700 ml/d, respectively, while these values for R1 reactor with pH adjustment were approximately equal to 200-300, 460-700, and 370-920 ml/d. The higher methane generation in R2 compared to R1 with pH adjustment is attributed to the bioconversion of CO2 to methane. Results showed that approximately 83-97% of the injected dissolved CO2 in R2 was removed by the proposed pathways.
The potential GHG reduction and economic feasibility of the developed process was evaluated by applying detailed calculations. GoldSETTM software was applied to compare the proposed developed process with conventional hybrid and aerobic treatment processes based on the sustainability aspects. The results of GoldSET software confirmed the higher sustainability of the developed hybrid treatment process compared to the conventional hybrid and aerobic treatment processes. Application of developed hybrid treatment process instead of conventional hybrid treatment process can annually save up to 3 million dollars in annual costs of treatment plants and will reduce GHG emissions by 100,000 tCO2e/y.
A numerical method based on the Runge-Kutta fourth-order method was developed to investigate the controlling kinetic parameters for anaerobic digestion of carbon dioxide. Results showed that the values of kinetic parameters estimated from the two experimental setups were very close. The obtained values for Ks and m for Cascades wastewater were 0.4g/l and 0.02/d, while these values for CTMP wastewater were 0.6 g/l and 0.025/d respectively. Results of both experiments showed that simulated values were in compliance with the experimental data and similar pattern during different experimental conditions were observed.


identifier: Kaddoura, Khalid  (2015) Automated Sewer Inspection Analysis and Condition Assessment.  Masters thesis, Concordia University.

abstract:
Underground infrastructure serves an essential need for the society. Huge number of facilities is dedicated to facilitate the well-being’s needs. Sewer infrastructure, one of the facilities, plays a major role in maintaining healthier environment. Its main duty is to transfer sewage material to treatment plants or any designated disposal area. Therefore, providing well performing sewer systems is essential to avoid any breakdown. Nevertheless, sewer pipelines’ condition in North America is deteriorating. In fact, studies have shown that 30% of municipal infrastructure in Canada is in either fair or very poor condition. As a result, there is a significant requirement for inspection and rehabilitation. Many municipalities utilize Closed Circuit Television (CCTV) inspection technique in inspecting sewer pipelines. However, this technique suffers from significant subjective and imprecise conclusions. Hence, studying, analyzing and applying different sewer inspection technologies and designing a condition assessment model are necessary to reduce subjectivity and errors and produce accurate and reliable results.
This research aims to develop an automated tool to quantify: deformation, settled deposits, infiltration and surface damage sewer defects. The automated approach is dependent upon using image processing techniques and several models to analyze output data from 2D laser profiler, sonar and electroscan. Other than using ASTM F1216 formula, the research suggests applying the roundness factor in quantifying the deformation defect.
The research develops a condition assessment model, based on the aforementioned defects, to arrive to an aggregated index suggesting the condition of sewer pipelines. Multi Attribute Utility Theory (MAUT) approach is used for each defect. The research also suggests a methodology to evaluate the surface damage defect of sewer pipelines for reinforced concrete, vitrified clay and ductile iron sewer pipeline materials. An interface, using MATLAB, was developed to implement the designed quantification algorithms and the MAUT model on real case studies.
After implementing and validating the two deformation quantification methods, the Mean Absolute Error (MAE) utilizing the ASTM F1216 was 4.27%, while the MAE using the roundness factor was 4.83%. The maximum difference percentage was found to be 40.06%; however, the minimum difference percentage was 0.59%. The average difference percentage for all the cases was calculated as 16.67%. Later, the MAUT model was validated with actual case studies. Three rounding types (rounding to nearest number, rounding up and down) were tested to change the aggregated index, containing decimals, to a whole number. Mean Absolute Error (MAE) was utilized to compare the rounding types. In all case studies, rounding up type produced the lowest MAE values. When rounding up the computed index in case study 1, the MAE for Concordia Sewer Protocol (CSP), Water Research Centre (WRc) and New Zealand were 0.33, 0.33 and 0.42, respectively.
This research shall encourage subject matters to utilize technologies, other than or beside CCTV, to conclude sound results. The developed automated user interface shall reduce inaccuracy and subjectivity through the application of robust image processing algorithms. After extending this research in including several sewer’s components and defects, the condition assessment model shall aid asset managers to allocate their maintenance and rehabilitation budgets.


identifier: Pilon, Anne  (2015) Entre Deux Chaises: A Study of the Liminal Space of the Artist Teacher.  Masters thesis, Concordia University.

abstract: This thesis describes how I use action research methodology to study how engaging in artistic creation has changed how I see my role as an artist. I use a participatory art approach to consider how I experience the roles simultaneously. The dual roles of the artist and teacher are like being in a liminal state, where one is said to be in between two distinct roles or states of being. Through creative processes, making art and using reflection methods, I investigate how I experience liminality as a metaphor for being both an artist and a teacher of art. Rather than viewing this dual role as a compromise of each of them, I demonstrate that the roles compliment and strengthen each other. I explore how being in the liminal space between an artist role and teacher role is an ideal environment for creativity.


identifier: Obara, Lukasz  (2016) Reciprocity Law For Flat Conformal Metrics With Conical Singularities.  Masters thesis, Concordia University.

abstract:
We study an analogue of Weils reciprocity law for flat conical conformal metrics on compact Riemann surfaces. We give a survey of
Troyanov’s paper concerning flat conical metrics. The main result of
this thesis establishes a relation among three flat conformally equivalent metric with conical singularities.


identifier: Quan, Siyu  (2016) Virtual Glasses Try-on System.  Masters thesis, Concordia University.

title: Virtual Glasses Try-on System

abstract:
Virtual Glasses Try-on System
Siyu Quan
Recent advances in data-driven modeling have enabled the simulation of wearing the glasses virtually based on 2D images (web-camera). For real-life glasses wearing, it needs not only suitable for appearance, but also comfort. Although the simulations based on 2D images can bring out certain conveniences for customers who want to try on glasses online first, there are still many challenging problems ahead because of the high complexity of simulations for wearing glasses. Obviously, it can hardly tell if the glasses are comfortable or can seat on the customer’s nose correctly. Furthermore, customers may want to take a look from different angle to make sure that the glasses selected are perfect. Such requirements cannot be met by using the simulations based on 2D images so we present an interactive real-time system with simulations for wearing glasses, providing users with a high degree of simulation quality including physics application. With our system the user uses the Kinect sensor or the common web camera as input device to acquire the result of wearing the preferred glasses virtually, which is real-time. Input device captures the user’s face and generate a geometry face-mesh which is expected to be aligned to the face-mesh template we pre-set manually. The 3D data captured from Kinect dramatically improve user’s experience by constructing geometry face mesh.


identifier: Gu, Junjie  (2015) GPU-Accelerated Boundary Element Method for Stress Analysis of Underground Excavations.  Masters thesis, Concordia University.

abstract: Stress analysis is one of the most important processes in designing an underground excavation. With the usage of numerical methods on a computer, such as the Boundary Element Method (BEM), the process of stress analysis can be made accurate. However, the computational implementation of stress analysis often requires considerable time and computational resources. For example, in the implementation of BEM, the finer the computational grid is, the longer time will take to compute the results. Based on the research of GPU-accelerated stress analysis in geomechanics (Zsaki, 2011), this thesis investigates one type of acceleration method, which used the parallel computing ability of modern graphics processing units (GPUs), for application to the traditional BEM algorithm. In this thesis, OpenCL was used as the framework to compile and execute programs on GPUs. By transferring and executing the most computational expensive parts of the traditional BEM code onto GPU, a respectable acceleration was achieved. Subsequently, with the application of a two-dimensional circular excavation example, the accuracy of the BEM algorithm implementation on a GPU was verified for both single-precision and double-precision calculations. In addition, two more excavation examples were taken into consideration to assess the accuracy and reduction in solution time. The performance for these three examples successfully verified the GPU-accelerating method and displayed an impressive acceleration effect with the speedup ratio of about 500 for single-precision and 15 for double-precision.


identifier: Hassan Beiglou, Ali Reza  (2015) Anatomic Characterization and Profilometry of Tissues with Natural Shape: A Real-time Approach for Robotic-Assisted Minimally Invasive Surgery.  Masters thesis, Concordia University.

abstract:
This master thesis is divided into two major sections. First, anatomic characterization and profilometry of tissues with natural shape: a real-time approach for robotic-assisted minimally invasive surgery (RMIS); and second, design and characterization of a novel tactile array sensor capable of differentiating among different viscoelastic tissues that exhibit time-dependent behaviour.
The first part of this thesis is focused on a tissue characterization system for RMIS applications. RMIS has gained immense popularity with the advent of high-precision robotic systems. The lack of haptic feedback, however, is considered as being one of the main drawbacks of present-day RMIS systems. In order to compensate for this deficiency, a novel tissue characterization system is proposed which is inspired from the human haptic system. Hence, kinesthetic and tactile feedback which are constitutive components of human haptic system are used to characterize naturally shaped tissues. Toward this goal, a 5-degree-of-freedom robot which is called Catalys5 is equipped with a ball caster force-cell. The system is used to simulate robotic surgery maneuvers in which an admittance control approach is implemented to design the force feedback controller. The proposed method characterizes naturally shaped tissues, which is capable of touching and palpating to: a) Identify the 2D or 3D surface profile of the target tissue (profilometry), b) Measure the modulus of elasticity of any desired point on the tissue’s surface, c) Find and map the location of any lump in the tissue, and d) Map hardness distribution around the lump.
Initially, silicon-rubber materials were used to build tissue phantoms with different curvatures and degrees of softness. The surface profiles were obtained using the developed profilometry algorithm and validated using a 3D scanner. In addition, several experiments were conducted on bovine tissues to evaluate all above mentioned capabilities of the system. The results of experiments on real tissues were also compared to those that are available in current literature. The results indicate that the proposed approach can be used for reliable material characterization for RMIS application.
The second part of this thesis is focused on developing an array tactile sensor for distinguishing softness of viscoelastic tissues with time-dependent behaviour for use in MIS and RMIS. Review of literature on tactile sensors reveals that the vast majority deals with determining the applied contact force and object elasticity. In this research, a novel idea is proposed in which a tactile sensor array can measure rate of displacement in addition to force and displacement of any viscoelastic material during the course of a single touch. In order to verify this new array sensor, several experiments were conducted on a range of biological tissues. It was concluded that this novel tactile sensor can distinguish among the softness of real biological tissue with time-dependent behaviour.


identifier: KAMKARRAD, HOSSEIN  (2016) High Repetition Rate Laser Shock Peening on Biodegradable Magnesium Alloys.  PhD thesis, Concordia University.

abstract:
Recently, Magnesium based alloys have been identified as a potential bio-degradable material for implants. While the biggest advantage of magnesium based implants is that it eliminates the need for additional surgery for removal, magnesium corrodes within human body much faster than the cure of broken bones. Hence, reduction of corrosion rate in magnesium surface is important to successful implementation. Laser Shock Peening (LSP) as mechanical treatment has been used successfully on implant surfaces to reduce the corrosion rate. Having reviewed the literature in LSP, it can be seen that the lasers used are low repetition rate high power lasers. Owing to cost of low repetition lasers, high repetition laser shock peening (HRLSP) is introduced in this work.

The general objective of this thesis dissertation is to develop HRLSP for low mechanical strength metals/alloys like Magnesium. To this end, a feasibility study of HRLSP was performed and pertinent laser parameters for successful peening of magnesium were evaluated. The finite element analysis using Abaqus Dynamic/Static was performed in both single shot mode as well as in multi shot mode. The simulation was used to predict the surface deformation on the peened area, magnitude of Compressive Residual Stress (CRS), and the propagation of CRS along the depth from the surface. The effect of laser parameters and scanning parameters on these values have been analyzed by Finite Element Analysis (FEA).

Based on the results from the feasibility study, an experimental setup involving both optical as well as scanning arrangement was performed and design of experiment was done for peening. From the experiments, with two laser intensities at 0.91GW/cm2 and 2GW/cm2, peening was possible only at 2GW/cm2. The magnitude of peening was varied by changing the %overlap between subsequent spots, and the total number scans. Increasing the number of peened shots within the specimen surface area of 10 X 10 mm, increases the magnitude of CRS that was shown by Finite Element Analysis. Comparison of peened samples to unpeened samples showed significant improvements in the mechanical attributes, comparable to that seen in the literature. The hardness increased from 45 HV to 103 HV; Surface roughness (Ra) increased from 0.35 m to 3.3 m; surface wettability measured as function of contact angle reduced from 68.5° to 44.4°; and wear resistance improved from 5.5E-4 gr/s to 1.8E-4 gr/s. The results mentioned above clearly indicate the relationship between improvements in mechanical attributes to the magnitude of peening.


identifier: Krasteva, Tsvetanka  (2016) Growing herbs at Concordia: learning through tradition.  Masters thesis, Concordia University.

abstract:
There are many opportunities for informal learning in and around universities.  At Concordia University, the Greenhouse and the Loyola Farm are the settings where students and community member grow many vegetables and herbs as volunteers or participants in the Internship program for the medicinal usage of herbs. Two main theoretical lenses are used in this thesis:  Kolb’s Experiential Learning and Mezirow’s Transformative Learning.
Three data sets are examined:  First, the results of semi-structured interviews of seven Concordia students; second, the documentary analysis of traditions and projects at  Concordia, from its inception, found in the archives and related to herbs and sustainability; third, the researcher’s personal experience gained working in the Loyola herb garden during the Internship program.
Eight themes were extracted from the data collected:  (1) Experience of being around one’s own garden; (2) Slowly learning to speak the language of herbs; (3) Capture and regeneration of traditional knowledge from personal and multi-generational networks; (4)Interest in alternative and traditional healing; (5) Critique of the capitalist, invasive ways of healing (the political); (6) Learning together - brings people together; (7) Traditional healing practices are regaining importance; (8) Volunteers see their involvement as adding something greater than themselves – what the Jesuit fathers described as “To be a man for others”.  These specific learning opportunities are embedded in the synergy of traditions of Concordia. I therefore hope that others will pick up some of these leads and continue the praxis launched by the exploratory research on which this thesis is based.


identifier: Hedayati Somarin, Iraj  (2016) DFA Minimization Algorithms in Map-Reduce.  Masters thesis, Concordia University.

abstract: Map-Reduce has been a highly popular parallel-distributed programming model. In this thesis, we study the problem of minimizing Deterministic Finite State Automata (DFA). We focus our attention on two well-known (serial) algorithms, namely the algorithms of Moore (1956) and of Hopcroft (1971). The central cost-parameter in Map-Reduce is that of communication cost i.e., the amount of data that has to be communicated between the processes. Using techniques from Communication Complexity we derive an O(kn log{n}) lower bound and O(kn^3 log{n}) upper bound for the problem, where n is the number of states in the DFA to be minimized,and k is the size of its alphabet. We then develop Map-Reduce versions of both Moore's and Hopcroft's algorithms, and show that their communication cost is O(kn^2 (log {n} + log {k})). Both methods have been implemented and tested on large DFA, with 131,072 states. The experiments verify our theoretical analysis, and also reveal that Hopcroft's algorithm -- considered superior in the sequential framework -- is very sensitive to skew in the topology of the graph of the DFA, whereas Moore's algorithm handles skew without major efficiency loss.


identifier: Pringle, Anna  (2016) Inevitable Extraction, Colonial Security, and the Making Recoverable of Unconventional Oil.  Masters thesis, Concordia University.

abstract: In 2002, the Athabasca tar sands in Alberta were re-classified as recoverable. This recovery required, and requires, a vision of the region that is long in the making; a vision that emerges within a history of colonialism. I begin by tracing out how post-Cold War imaginaries of the tar sands presented the resource as crucial to the future viability of North American ‘democratic’ states. These envisionings of energy security, I argue, build, and tap into, prior colonial imaginaries of the region as wild and empty. In my first chapter, I look at how the Boreal forests of Athabasca had to be emptied out of certain dissenting interrelations and populations in order for oil to appear, although, this emptying out was never completely successful. Subsequently, in my second chapter, I build on this argument by contemplating how shifting discourses of wildness, legality, order, safety, and violence, allowed land to become frontier while granting legitimacy to colonial regimes of violence. I conclude by examining how prior visions of abundance acted as the extractive scaffolding for the 2002 recovery. What I hope to emphasize is that the visions of abundance in 2002 are interwoven with long-held colonial anxieties surrounding security. Further, the recovering of resources in Alberta was never inevitable, rather, it occurred through a multiplicity of encounters, between both human and nonhuman communities, all brimming with contingency.  I close by posing the question, how can we radically re-imagine the land, each other, and deeply ingrained notions of security, violence, and belonging?


identifier: Kharma, Nawwaf  (2015) Automated Design and Empirical Validation of Hammerhead Ribozymes.  Masters thesis, Concordia University.

abstract:
Ribozymes are catalytic RNA molecules. Hammerhead ribozymes are one of a set of ribozymes capable of cleaving RNA molecules, in cis and in trans, without the help of other molecules, such as proteins. A trans-acting hammerhead ribozyme has a few related forms, which can be customized to target specific sites within RNA strands, including the transcripts of genes. As such, hammerhead ribozymes can be used to down-regulate or even silence any gene with valid cut-sites. All, except very short transcripts, will have multiple valid cut-sites. However, the efficiency of silencing by a hammerhead ribozyme depends on multiple often conflicting factors. Also, the efficiency of cleavage of any one ribozyme is normally low. Hence, it is useful to automate the process of design of hammerhead ribozymes to efficiently and without error explore the large space of possible designs. Computers are simply better than humans in doing a large amount of repetitive work without error.
This thesis describes an original computational algorithm that allows for the automated design of hammerhead ribozymes; the algorithm was implemented as a web service, by our collaborators, and is now freely available via the Internet. The algorithm takes into account all the relevant mathematically-modeled factors, influencing cleavage efficiency & target specificity, including cut-site availability, cut-site accessibility, ribozyme secondary structure, annealing temperature and off-target effects. Given an input sequence or gene, the algorithm proposes a list of potential hammerhead ribozymes that can, in theory, cleave the given RNA sequence. The latter part of this thesis describes the wet lab work, which involved the in vitro and hence, in vivo testing of several ribozymes targeting the transcript of the PABPN1 gene. This gene is the primary cause of a human disease, OPMD (Oculopharyngeal muscular dystrophy).
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We describe the experimental methods used to test the cleavage efficacy and reaction kinetics of a small number of hammerhead ribozymes generated by the computational algorithm. We measured the in vitro transcript cleavage efficiency and enzyme kinetics, as well the in vivo gene knockdown effect of individual ribozymes. We also measured the enhanced effect of using combinations of two or more ribozymes all targeting the same transcript. Finally, we design a mutant PABPN1 gene that gives the same protein as the wild type gene, but one that generates a transcript supposedly immune to the catalytic activity of hammerhead ribozymes. We test this hypothesis, in vivo, and provide the results.
The results show that (a) every one of the ribozymes generated by the computational algorithm is a functional ribozyme; (b) the use of two or more ribozymes increases the overall cleavage efficiency; (c) these ribozymes are effective both in vitro and in vivo; (d) the immune transcript is not affected by any ribozyme. Hence, the computational algorithm is an effective design tool. The use of at least two hammerhead ribozymes is clearly more effective than one. And finally, it is possible to generate a hammerhead ribozyme (or more) that would cleave the transcript of a given gene (say PABPN1), while not cleaving the transcript of a mutated version of the gene, one that codes for the same protein as the original gene. This opens the door to potential therapeutic applications of our approach, perhaps where other gene editing approaches cannot be employed.


identifier: Birkas, David  (2015) Towards a data-driven object recognition framework using temporal depth-data.  Masters thesis, Concordia University.

abstract: Object recognition using depth-sensors such as the Kinect device has received a lot of attention in recent years. Yet the limitations of such devices such as large noise and missing data makes the problem very challenging. In this work I propose a framework for data-driven object recognition that uses a combination of local and global features as well as time varying depth information.


identifier: Jia, Hanxin  (2016) A Render Model For Particle System.  Masters thesis, Concordia University.

title: A Render Model For Particle System

abstract:
Particle system is a very commonly used system in computer graphics. It can be used to simulate
many objects in the real world, such as liquid simulation, smoke simulation and so on. Now, a
new method called welding simulation has been developed. In this simulation, it needs to give the
particle system a metal-like surface. Therefore, in this thesis, we developed a render model which
can make a particle system have a metal-like surface. This render model can be used in welding
simulation application and also for other applications based on particle systems with metal-like
surface


identifier: Lunny, Debbie  (2016) Citing/Siting Transnational Feminisms: Academic and Activist Epistemologies.  PhD thesis, Concordia University.

abstract: This dissertation addresses the place of transnational feminist activisms (TFA) and especially transnational feminist activist knowledges (TFAK) within the emerging field of transnational feminist studies (TFS). It investigates how TFS developed with so little engagement with TFA/K. The central question used to explore the gap between TFA and TFS is: how is “transnational feminisms” socially and conceptually organized? Using a blended methodology drawn from institutional ethnography and political activist ethnography, I conduct a textual analysis of the academic TF literature as data. More specifically, I explore how conventional scholarly practices socially and conceptually organize the orientations taken by Northern university-based scholars to transnational feminist activisms and their knowledges. I argue that these academic knowledge production practices – citational praxis, citational theorizing, citational disciplining, definitional debates, and frame replacement – have operated and continue to operate as field-building mechanisms during the period when transnational feminisms emerge within the North American academy, constraining lines of inquiry, priorities, and interlocutors. I contend that TFA/K are overwritten in this process, skewing the development of TFS away from movement-engagement and towards a recentering of North American academic positionalities. This interdisciplinary dissertation draws upon Social Movement Learning (SML) and my own experiential learning through TFA in Japan/Asia, in order to suggest ways to make activists’ informal learning (IL) and TF movement knowledges more visible in TFS. I argue for the importance of recognizing the context-specific nature of TF activist and academic epistemologies as well as the importance of consciously shifting scholarly orientations to TFAK and IL. The dissertation makes a number of original contributions. It is the first in-depth study to offer an examination of the potential for a synthesis of TFS and SML. The data analysis offers original insights about: a) the role of citational disciplining and citational theorizing within TFS, b) the social and conceptual organization of scholarly orientations towards TFA/K through conventional and subversive academic knowledge production practices that function as field-building mechanisms during the emergence of the field of TFS, c) the ways in which North American scholarly positionalities are recentered even in much TF scholarship on TFA, and d) strategies to make visible and explicit the informal learning and knowledge production that are central to TFA through an interdisciplinary TFS/SML framework.


identifier: Qing, Gu  (2016) GPU Based Real-time Welding Simulation with Smoothed-Particle Hydrodynamics.  Masters thesis, Concordia University.

abstract: Welding training is essential in the development of industrialization. A good welder will build robust workpieces that ensure the safety and stability of the product. However, training a welder requires lots of time and access professional welding equipment. Therefore, it is desirable to have a training system that is economical and easy to use. After decades development of computer graphics, sophisticated methodologies are developed in simulation fields, along the advanced hardware, enables the possibility of simulation welding with software.  In this thesis, a novel prototype of welding training system is proposed. We use smoothed-particle hydrodynamics (SPH) method to simulate fluid as well as heat transfer and phase changing. In order to accelerate the processing to reach the level of real-time, we adopt CUDA to implement the SPH solver on GPU. Plus, Leap Motion is utilized as the input device to control the welding gun.  As the result, the simulation reaches decent frame rate that allows the user control the simulation system interactively. The input device permits the user to adapt to the system in less than 5 minutes.  This prototype shows a new direction in the training system that combines VR, graphics, and physics simulation. The further development of VR output device like Oculus Rift will enable the training system to a more immersive level.


identifier: Haneef, Anhar  (2016) On the Scalable Generation of Cyber Threat Intelligence from Passive DNS Streams.  Masters thesis, Concordia University.

abstract:
Domain Name System (DNS) has become an important element of recent cybercrime infrastructures. Indeed, DNS protocol is being used, for instance, to operate infected machines and transport malicious payloads. In this context, it is of paramount importance to analyze passive DNS streams in order to generate timely and relevant cyber threat intelligence that can be used to detect, prevent and attribute cyber attacks. In this thesis, we explore the analysis of the aforementioned streams in order to detect DNS anomalies that correspond to cyber incidents. By DNS anomaly, we mean any deviation from what is expected in terms of regular DNS activities (queries/responses). The
identification of these anomalies leads to precious intelligence that could pinpoint domains that are involved in malicious activities (e.g., spamming, botnets, phishing, DDoS, etc.). We propose, design and implement a system that analyzes, in near-real-time, passive DNS streams and generates cyber threat intelligence in terms of: suspicious domains, DNS record abuse and passive DNS anomalies. We correlate the generated intelligence  with other sources of intelligence such as our malware database. We dedicate a special care to the scalability of the proposed system. In addition to picking appropriate data structures and database technologies, we proceed with the distribution of the analysis over a cluster of computers using the so-called map/reduce paradigm with the Apache Spark framework. Our experiments show that our system is efficient and scalable while generating important, relevant and timely cyber threat intelligence.


identifier: Muir, Gwendolyn  (2015) Unmapping Recruitment: An Exploration of Canada's Temporary Foreign Worker Program in Guatemala.  Masters thesis, Concordia University.

abstract: Migrant workers have made up the largest category of legal entrants to Canada over recent years, with 491,547 working in Canada in 2012. This rise of temporary “managed migration” has been organized through discriminatory classification systems that are deeply rooted in colonial categories of difference, sorting migrants according to nationality, gender, race, etc., while normalizing the exclusion of workers from full status. Although managed migration has come to dominate Canada’s bordering landscape, little research has explored how the colonial underpinnings of temporary labour facilitate the apartheid of mobility in Canada, and, in particular, how the neoliberalization of migration governance has also tightened state control over the movement of non-White workers. In this thesis, I unmap TFWP recruitment in the “Low-Skill” Canada-Guatemala Pilot Project to highlight how temporary bordering practices perform and uphold the settler state through the stratified classification and management of migrant labour. I draw from a total of twelve qualitative interviews with all seven recruitment agencies active in Guatemala in 2014 and one agency in Canada, as well as from the lived experiences of thirty-nine Guatemalan workers shared over nineteen interviews. Through an interrogation of the day-to-day agency narratives and processes that forge the “good” worker and the migrant worker category in Guatemala and Canada, I trace how the TFWP is continuously constructed through the tangible practices of agencies, employers, and the Canadian state. I demonstrate how the expansion of the TFWP via recruitment has consequences far beyond Canada’s physical borders, driving workers into debt and precarity, fraudulently enlisting and blacklisting workers, and promoting overt discrimination on the basis of race, gender, region, climate, morality, ability, etc. Through an examination of bordering actors and narratives, I denaturalize the unjust organization of managed movement and Canadian borders, unmapping the processes of differential classification and containment in support of a wider no borders politics.


identifier: Han, Wei  (2016) Integration of Multiple Uncertain Data Sources.  Masters thesis, Concordia University.

abstract:
Data integration is the problem of combining data from multiple autonomous data
sources, and providing a unified view to the users. The problem has been studied
extensively over the past two decades, and focused more on integrating traditional, exact
relational data. Integration over uncertain data sources is a more recent problem
and a more challenging one. The purpose of this thesis is to understand the semantics
and techniques of uncertain data integration over multiple such data sources.
We study existing proposals for uncertain and probabilistic data integration. As a
basis of our work, we consider two integration operations, one in the possible worlds
model, and the other in a compact model. We introduce the properties of the integration
operations proposed for two sources, and consider these properties to develop
a framework for integrating multiple sources. For this, we also extend and generalize
a conversion algorithm from possible worlds model to the compact probabilistic relations.
We define the integration procedure, the concept of probability consistency,
and a probability adjustment method when the consistency is violated. We build a
running prototype of the proposed framework to show its feasibility and to automate
the probability calculation. This thesis makes a step forward to better understand
the challenges and development of uncertain data integration systems.


identifier: Keough, Matthew T  (2016) Clarifying the revised Behavioural Inhibition System as a Risk Factor for Anxiety-Related Alcohol Misuse in Young Adulthood: New Insights from Experimental and Prospective Studies.  PhD thesis, Concordia University.

abstract:
ABSTRACT
Clarifying the revised Behavioural Inhibition System as a Risk Factor for Anxiety-Related Alcohol Misuse in Young Adulthood: New Insights from Experimental and Prospective Studies

Matthew Keough, Ph.D.
Concordia University, 2016

Theoretical models posit that anxious persons drink alcohol to self-medicate negative emotions. However, existing data suggest that the anxiety pathway is complex. While there is high comorbidity of anxiety and alcohol use disorders in adults, evidence earlier in the risk trajectory (in young adulthood) is highly mixed. Gray’s Reinforcement Sensitivity Theory (RST) provides a useful framework for clarifying the anxiety-drinking pathway in young adults. The RST implicates the behavioural inhibition system (BIS) as a risk factor for alcohol misuse. Important theoretical revisions were made to the BIS 15 years ago, but these changes have been slow to enter the empirical literature. The revised BIS is a motivational conflict system. In response to competing goals (e.g., reward vs. punishment), the revised BIS inhibits behaviour, giving rise to high anxiety, attention to threat, and behavioural ambivalence. Accordingly, BIS-anxiety may promote self-medication drinking, while sensitivity to motivational conflict may lead to indecisiveness about drinking and attention to threat. Theory suggests that a strong Behavioural Approach System (BAS) should enhance the anxiolytic effects of alcohol use, which should be salient to those high in the BIS. However, few studies have been able to examine these interactive effects since most work has not tested the predictions of the revised RST. Using experimental (Study 1) and prospective (Study 2) studies, the primary aim of this dissertation was to clarify the BIS-related pathway to alcohol misuse among young adults. Study 1 (N = 110) was an experimental design that aimed to examine the cognitive mechanisms of this pathway. Results demonstrated that individuals with a strong BIS and a strong BAS expected elevated positive mood (rather than reduced anxiety) in response to an alcohol cue when feeling anxious. Study 2 (N = 119) sought to examine the BAS as a moderator of BIS-risk for alcohol misuse during the transition out of university. Findings indicated that those high in the BIS showed impeded maturing out of alcohol misuse during this transition if they were also strong in BAS impulsivity. Conversely, young adults with a strong BIS rapidly reduced alcohol misuse if they were concurrently low in BAS impulsivity. Overall, the moderating role of the BAS clarified BIS-risk for alcohol misuse. Findings shed light on the cognitive mechanisms underlying BIS-related drinking and provide a first look on how the BIS and the BAS interact to set the stage for long-term alcohol problems in young adulthood.


identifier: Eskandari, Shayan  (2015) Real-world Deployability and Usability of Bitcoin.  Masters thesis, Concordia University.

abstract:
We live in an era where Internet is one of the daily needs of human life. People use Internet banking instead of going to banks, they use email rather than postal mail.This leads to a robust digital way of living, but this also means people are trusting middle companies and third parties for their online services. The need of having a digital form of money that is not being controlled by one entity is plain to see.
Bitcoin is the first and the most popular decentralized virtual currency. It is based on cryptographic functions to remove the need of a central bank and regulates the generation of new units.
In this thesis, we would like to look at available tools to facilitate users in holding and using Bitcoin by a perspective on usability and security, and then evaluate the possibilities for a small business to accept Bitcoin payments. Our focus is on the usability of these tools and developing a useful framework for comparing and eval- uating future tools. While many security tools have been studied from a usability perspective, our work is the first to look at Bitcoin.


identifier: Zhou, Linyi  (2016) Mergers and Acquisitions Deal Initiation and Motivation.  Masters thesis, Concordia University.

abstract: This study examines potential motivations for firms to initiate a merger or acquisition, and investigates the relation between the deal initiator and firm performance, premiums, payment method, and time to completion. Using a sample of U.S. mergers and acquisitions from 2006 – 2012, we find that both target cumulative abnormal returns (CARs) around the announcement date and takeover premiums are significantly lower in target-initiated deals than in bidder-initiated deals (confirming findings of Masulis and Simsir, 2015). Moreover, we find that target-initiated deals utilize more cash as a means of payment (perhaps a byproduct of targets approaching cash-rich bidders), have a shorter time to deal completion, and provide higher long-term buy-and-hold abnormal returns (BHAR) to acquiring firms. Lastly, we show that target firms in target-initiated deals are more financially distressed, providing motivation for such targets to initiate the deal, hurry it along, and accept the lower returns offered.


identifier: Huppler, Lise  (2016) Executive Functioning Deficits: A Remedial Intervention for Middle School Students with Organizing and Planning Difficulties.  Masters thesis, Concordia University.

abstract: Deficits in executive functioning (EF) skills, a typical characteristic of students with attention deficit/hyperactivity disorder (ADHD), negatively impacts adolescents' academic functioning and performance (Barkley, 2012). The purpose of this qualitative study was to better understand the student outcomes of the Homework, Organization and Planning Skills (HOPS) program (Langberg, 2011), a 16-sessions intervention designed to improve these skills in middle-school students with ADHD, and identify the different elements that may impact the degree of success, feasibility and dissemination of the program as perceived by three middle-school students, their parents and one of their teachers. In addition, the replacement of the HOPS paper calendar by a digital equivalent for tablets was also explored. Both qualitative (interviews) and quantitative (behaviour rating scales) data were collected from each of the three participants, their parents and one teacher prior to and following the completion of the HOPS intervention. Findings suggest that the HOPS program yielded progress in the area of homework completion and planning of academic schoolwork and organization of material. Also, although both parents and teachers noted academic improvements, teachers observed more moderate progress. In addition, the length and timing of the sessions were perceived as the program's strengths, whereas the level of parent involvement and the student's level of independence at the end of the intervention were deemed a difficulty.


identifier: Soudi, Amirreza  (2016) An Anomaly Detection System based on Ensemble of Detectors with Effective Pruning Techniques.  Masters thesis, Concordia University.

abstract:
Anomaly detection systems are important tools for security. Unlike signature-based systems, anomaly detection can be used to detect new attacks for which signatures are now available.

To this end, anomaly detection techniques rely on machine learning techniques to model the normal behaviour of the system. This model is used as a baseline for the detection of anomalies during system operation.

The problem is that there is no one machine learning technique that can provide good accuracy. What we need is to combine multiple techniques. This is because ensemble methods have been used to improve the overall detection accuracy in traditional machine learning.

The combination consists of combining the outputs of several accurate and diverse models. To reduce the number of combination, and hence improve the efficiency of combination, in this thesis, we propose PBC (Pruning Boolean Combination), an efficient approach for selecting and combining anomaly detectors. PBC relies on two novel pruning techniques that we have developed to  prune redundant and trivial detectors. Compared to existing work, PBC reduces significantly the number of detectors to combine, while keeping similar accuracy. We show the effectiveness of PBC when applying it to benchmarks data sets.

Much of the content of this thesis is adapted and expanded from a paper published at the 2015 IEEE International Conference on Software Quality, Reliability and Security (QRS). QRS is a merger of the SERE conference (IEEE International Conference on Software Security and Reliability) and the QSIC conference (IEEE International Conference on Quality Software)


identifier: Mashhour, Ibrahim  (2016) Experimental Study on Negative Skin Friction on Piles In Collapsible Soils Due to Inundation.  PhD thesis, Concordia University.

abstract:
Collapsible soil is a special type of soil, classified as problematic soil. It possesses a high strength in the unsaturated phase and loses its strength and exhibits substantial settlement when inundated. Many foundation failures occur around the world, many of which involve loss of lives, caused by problems associated with collapsible soils. One of the most commonly used type of foundation in collapsible soils is end-bearing piles resting on firm soil strata. However, these piles will be subjected to negative skin friction during wetting of the collapsible soil, inducing additional loads. Various case studies have reported foundation failures and excessive settlements upon the wetting of collapsible soil.
Researchers are facing serious challenges in dealing with piles in collapsible soils due to the complexity of the problem and the difficulties associated with modeling this behaviour numerically and experimentally. Relatively few investigations pertinent to pile foundations in collapsible soils subjected to inundation are available in the literature.
An experimental investigation was carried out to simulate the complex interaction between collapsible soil and a single end-bearing pile under various wetting and loading conditions. The experimental prototype setup was developed and calibrated in the laboratory in order to measure the drag load and accordingly the negative skin friction acting on the pile’s shaft for given soil/wetting/loading conditions. Collapsible soils with different collapse potential values were
ii
created in the laboratory by mixing kaolin clay with fine sand at predetermined ratios. A two-dimensional axi-symmetrical numerical model was generated in order to conduct a parametric study by extending the data for a wider range. The numerical model was validated by experimental results obtained from this study. Based on the results obtained from the experimental and numerical models, a design theory capable of taking into account the effect of soil collapse under different wetting schemed was developed and recommended for use in practice.


identifier: Aktas, Osman Ulas  (2016) Three Essays on the Microstructure of the BIST.  PhD thesis, Concordia University.

abstract:
ABSTRACT
Three Essays on the Microstructure of the BIST
Osman Ulas Aktas, Ph. D.
Concordia University, 2016
	This thesis consists of three essays. The first essay (chapter 2) examines the accuracy of five algorithms for classifying trades as buyer- or seller-initiated for BIST-30 index constituents over a period including the Lehman collapse. The highest classification accuracy rate (over 95%) is for the one-second lagged Lee & Ready (LR) algorithm. The LR’s classification accuracy is highest (lowest) for trades representing mixed agency and principal (pure principal) relations between clients and executing brokers. Unlike for U.S. markets, almost all trades are classifiable with accuracy rates of 90-plus percent for both long and short trades. As for U.S. markets, higher misclassification rates occur for trades in the first versus last 30 minutes of the trading day, as the time between consecutive trades decreases, and for decreasing trade sizes.
	The second essay (chapter 3) examines the trade price effects and their determinants for BIST-30 index constituents for a period that includes the Global Financial Crisis and the Lehman collapse. Consistent with theoretical predications, we find that informed trades in the BIST tend to be large. Our findings that price discovery appears to be fairly rapid on the BIST and that the average multi-sample stock trade price effect of less than 30 basis points is competitive with other markets have important implications for the purchase and execution decisions of investors. Our finding of positive mean price effects for short trades that are larger for seller-initiated trades and larger than for long trades has implications for the ongoing debate about the regulation of short sales since it suggest that the average short sales does not depress prices. Furthermore, the higher price effects of (especially buyer-initiated) trades in the last minutes of a trading session and the variation in price effects with whether the client-broker relationship is agency, principal or mixed have important implications for market regulators in terms of refining their surveillance systems to better control any inappropriate stealth trading or end-of-session price manipulation.
	The third essay (chapter 4) examines the price-limit hits for members of the BIST-50 index during the March 2008 through March 2009 period. The effects of price-limits are not homogeneous for upper and lower hits when they occur and if they continue in a subsequent trading session. Our results are supportive of the no-, dampening and spillover effects on volatility hypotheses, overreaction and no-effect price hypotheses, magnet price effect hypothesis, and greater informational asymmetric effect on market-quality hypothesis. They are not supportive of the price-delay hypothesis, and trading interference hypothesis. The results are robust using equi-distant and trade-by-trade returns and volatility measures ccounting for the autocorrelations in these return series. The results have implications for regulators contemplating the introduction of similar mechanisms or fine-tuning their current mechanisms.


identifier: Riad, Keroles B.  (2016) Photocuring epoxy with quantum dots for 3D printing.  Masters thesis, Concordia University.

abstract:
3D printing is the future of manufacturing, limited by material development. Stereolithography is an ideal 3D printing process as it is energy efficient, accurate, fast and capable of forming composite materials. The photocuring of polymers used in this process is integral to society via more applications such as dentistry, coating, and printed circuit boards. However, those photosensitive materials are unstable in daylight during end use limiting their viability for making functional parts in many applications, motivating our work. The ultimate goal is to photocure only with light outside of the solar spectrum on Earth in stereolithography 3D printing, which motivates this work, to produce photostable parts.
While semiconducting nanoparticles have previously been shown to photocure acrylic resins via a free radical mechanism, here we demonstrate, for the first time, that semiconducting nanoparticles are capable of photocuring epoxy cationically. This result is critical because with that achieved, the quantized effect can be used to increase the band gap energy of the nanoparticles to only be sensitive to light outside of the solar spectrum on Earth.
We study both bulk and quantized nanoparticles, propose a reaction mechanism supported by experimental observations, and explore the effects of process variables on the kinetics of the reaction. The intertwining of the engineering of the application, the chemistry of the reactions and the physics of quantum dots makes this thesis a truly rich, interdisciplinary study.


identifier: Ebrahimi, Dariush  (2016) Compressive Data Gathering in Wireless Sensor Networks.  PhD thesis, Concordia University.

abstract:
The thesis focuses on collecting data from wireless sensors which are deployed randomly in a region. These sensors are widely used in applications ranging from tracking to the monitoring of environment, traffic and health among others. These energy constrained sensors, once deployed may receive little or no maintenance. Hence gathering data in the most energy efficient manner becomes critical for the longevity of wireless sensor networks (WSNs).

Recently, Compressive data gathering (CDG) has emerged as a useful method for collecting sensory data in WSN; this technique is able to reduce global scale communication cost without introducing intensive computation, and is capable of extending the lifetime of the entire sensor network by balancing the forwarding load across the network. This is particularly true due to the benefits obtained from in-network data compression. With CDG, the central unit, instead of receiving data from all sensors in the network, it may receive very few compressed or weighted sums from sensors, and eventually recovers the original data.

To prolong the lifetime of WSN, in this thesis, we present data gathering methods based on CDG. More specifically, we propose data gathering schemes using CDG by building up data aggregation trees from sensor nodes to a central unit (sink). Our problem aims at minimizing the number of links in the forwarding trees to minimize the number of overall transmissions. First, we mathematically formulate the problem and solve it using optimization program. Owing to its complexity, we present real-time algorithmic (centralized and decentralized) methods to efficiently solve the problem. We also explore the benefits one may obtain when jointly applying compressive data gathering with network coding in a wireless sensor network. Finally, and in the context of compressive data gathering, we study the problem of joint forwarding tree construction and scheduling under a realistic interference model, and propose some efficient distributed methods for solving it. We also present a primal dual decomposition method, using the theory of column generation, to solve this complex problem.


identifier: Elhassan, Wael  (2016) 3D Modeling of Indoor Building Geometry Using Unmanned Aerial Systems.  Masters thesis, Concordia University.

abstract:
As-built Building Information Models (BIMs) can significantly enhance the efficiency of facility management and operations. However, they are seldom used in the architecture, engineering, construction, and facility management (AEC/FM) industries due to the difficulty of collecting the spatial information required to create such BIMs. Typically, this spatial information is collected through manual field surveys, which are time-consuming and error-prone. Therefore, image-based sensing techniques have been proposed and tested for the three-dimensional (3D) modeling of spatial information using images captured by handheld cameras. Moreover, with recent technological advancements, Unmanned Aerial Systems (UAS) equipped with high-definition cameras have become a powerful tool for remote image acquisition.
So far, it is still not clear whether images remotely captured by a UAS can be used for the 3D modeling of indoor building environments. The main objectives of this research were: (a) to test the feasibility of using a UAS for the 3D modeling indoor building environments, and (b) to evaluate the effectiveness of using the UAS for 3D modeling in terms of accuracy, density, time, and cost. In order to achieve these objectives, a UAS is first deployed to collect several overlapping images of an indoor building environment. Next, a Structure from Motion (SfM) algorithm is applied to generate a 3D point cloud that represents the spatial information of the indoor building environment. Later, the accuracy and density of this 3D point cloud were evaluated by comparing it with the ground truth point cloud generated from a laser scanner. The time and cost needed for modeling using the UAS were also recorded and compared with the ones from the laser scanner. This framework was applied in two case studies: (1) the 12th floor of the Hall building, and (2) the 2nd floor of the EV building, at Concordia University. The results of these studies showed that 80% of the 3D points had a deviation of up to 8.8 cm from the ground truth. Approximately 20% of those points had a deviation of 0.81 cm or less. Overall, these studies demonstrate that UAS-based modeling is able to model the spatial information of indoor building environments with dense point clouds and with acceptable accuracy. Furthermore, the studies also indicate that the 3D modeling of spatial information with a UAS can be a time- and cost-effective approach.


identifier: Hart, Laurel Marie  (2016) Her Mind’s Eye: Women’s Visions of Urban Life Explored in a Place-Based Social Mobile Photography Community Online and On the Ground.  PhD thesis, Concordia University.

abstract:
This study employs community action research and arts-based research to explore collaborative development of the women’s mobile photography community, Her Mind's Eye. Her Mind’s Eye is an exploratory, creative and contemporary women’s mobile photography community that exists both physically (through in-person meetings) and digitally (in online social media spaces). The group was designed to support women in learning and inquiring into mobile photography and new technologies within an encouraging, flexible, and supportive art creation community.
At the same time, it looks at the women’s uses of the social/mobile photographic medium itself, finding that it was used for: personal memory keeping, communication, jumpstarting relational connectedness, experiencing an increased sense of awareness of one's environment, and of others’ ways of seeing and being in cities. Through this community, we expanded the possibilities of collaborative and informal education, meeting in-person and on the social media platforms Facebook and Instagram. We found that these social media applications can be utilized to create “real life” connections between diverse individuals with like interests, in order to form city-based, digital/physical composite networks of people interested in creative photographic development. Simultaneously, we investigate how experiences of physical places (the cities of Montreal and Vancouver) can be shared in the digital world.
In addition to developing new networks and opportunities for creative growth, the group has a goal of exhibiting and promoting each woman’s artwork, and exploring women’s views and experiences of living in urban environments. Her Mind’s Eye held one exhibition during the time of this study, and several more afterwards. Lastly, it was found that the presence of group traits and structural supports similar to those within feminist pedagogy, such as an ethics of care, and sense of community, were fundamental to the successful operation of Her Mind’s Eye. Finally, having emerged from research origins, Her Mind’s Eye developed the unique form of a micro-SMP community, containing several clearly delineated boundaries, those of: group size, committed participation, and a defined focus. This made for a very successful community of inquiry and creativity, which however, poses questions for long-term group sustainability.


identifier: Wright, Kristyn  (2015) Biological motion perception and the animate-inanimate distinction in typically-developing children and children with Autism Spectrum Disorder.  PhD thesis, Concordia University.

abstract:
The present dissertation had two main objectives. The first objective was to investigate the development of naïve biological reasoning among typically-developing (TD) children and children with high-functioning Autism Spectrum Disorder (HF-ASD). Secondly, the potential link between biological motion understanding and the ability to form the animate-inanimate (A-I) distinction in both TD and HF-ASD children was evaluated. The first study examined the development of the A-I distinction among typically-developing 4- and 5- year-old children, and established that around 5 years of age children are able to form taxonomic A-I categories. Interestingly, when given the opportunity to form categories based on either taxonomic or thematic rules many children switched to categorizing thematically.
     The second study examined another aspect of naïve biology, namely the ability to identify biological motion among TD children and children with HF-ASD. This study was the first to compare point-light and schematic presentations of biological motion. The point-light biological motion task required children to identify degraded motion of a human, a cat, a bicycle, and a truck. The schematic biological motion task tested whether children associate expansion-contraction motion with the animate category. Across both motion identification tasks children with HF-ASD were unimpaired in identifying biological motion.
       The final study investigated the development of naïve biology among children with HF-ASD and also sought to determine whether motion perception is linked to the formation of A-I concepts. Children with HF-ASD were unimpaired in their ability to form broad A-I categories. In contrast to what has been found during the infancy period, TD preschool children did not prioritize motion cues when forming A-I categories. Rather, it is hypothesized that pre-school children rely on more global representations of naïve biology that include other non-obvious attributes of animates. Similarly, among children with HF-ASD no relationship between prioritization of attention to biological motion and children’s ability to form the A-I distinction was found. However, children with HF-ASD who engaged more in the active process of visually comparing biological and non-biological motion were better at forming A-I categories. Taken together, the results of these studies indicate that children with HF-ASD were unimpaired on multiple aspects of naïve biological reasoning, specifically, A-I taxonomic category formation and the identification of biological motion. Additionally, the results of this research also suggest that while TD infants rely on motion cues to guide the formation of A-I categories, school-aged children use more global representations of naïve biology that include other perceptual cues and features.


identifier: Mahdipoor, Mohammad Sadegh  (2016) Water Droplet Erosion Resistant Materials and Surface Treatments.  PhD thesis, Concordia University.

abstract:
Water Droplet Erosion (WDE) is a mechanical degradation which is of great concern to power generation and aerospace industries, where water droplets interact with high-speed moving components. It is observed on multiple components of airplanes when flying in the rain, on steam turbine blades, and gas turbine compressor blades which is the focus of this study. Compressor blades in gas turbines suffer from WDE due to the recently implemented technology Inlet Fog Cooling. It is utilized to boost gas turbine efficiency in high ambient temperatures via the spraying of micro-sized water droplets into the intake air. Evaporation of water droplets cools the intake charge and increases the air density. The main drawback of inlet cooling is that part of the water droplets are carried into the compressor by intake air flow, which is called overspray. Repetitive impact between rotating blades and water droplets leads to WDE damage, which is a major problem.
This study attempted to improve WDE resistance of compressor blades made of Ti6Al4V. Two different approaches were considered: Studying WDE of TiAl alloy as a potential erosion resistant material for turbine blades and Surface engineering of Ti6Al4V via gas nitriding and HVOF spraying of WC-Co. To investigate WDE in this work, erosion experiments were carried out using the state-of-art WDE rig available at Thermodynamics of Materials Group (TMG), Concordia University. It enables control of erosion conditions such as impact velocity, impact angle, droplet size, and droplet impingement number.
In the first stage of this study, WDE of nearly fully lamellar TiAl alloy was directly compared to Ti6Al4V at relatively wide ranges of impact speed (i.e. 275m/s, 300m/s, 325m/s and 350m/s) and droplet size (i.e. 464µm and 603µm). TiAl demonstrated superior erosion performance (i.e. longer incubation period and slower material loss) compared with Ti6Al4V at all tested conditions. Herein, the relation of impact velocity and maximum erosion rates for TiAl and Ti6Al4V alloys was established and the damage threshold speeds of TiAl were determined. Afterwards, the erosion behaviour of TiAl was related to its mechanical properties and irregular microstructure. Lastly, in-depth investigation was carried out to reveal erosion damage mechanism of TiAl at different stages including incubation, material loss initiation, maximum erosion rate, and advanced stages.
In the second stage of this study, the influence of gas nitriding on water droplet erosion behaviour of Ti6Al4V was investigated. Ti6Al4V coupons were nitrided at two different temperatures (i.e. 900 and 1050°C) for 5 and 10 hours and the nitrided coupons were characterized. Their erosion behaviour in comparison with as-received and annealed Ti6Al4V was examined at two impact speeds (i.e. 300m/s and 350m/s). Mechanical properties, erosion performance and damage mechanism of treated Ti6Al4V were significantly influenced by the nitriding temperature. Exploring the potential of HVOF spray WC-Co coating to combat WDE was the last part of this study. Erosion performance of two WC-Co coatings was examined at 250m/s, 300m/s and 350m/s impact speeds in comparison with Ti6Al4V. The as-sprayed coating did not show notable WDE protection; however, removing its top layers and smoothing its surface notably improved the erosion performance.


identifier: Grewal, Ramandeep Kaur  (2016) Spectral Descriptors for Data Clustering and Classification.  Masters thesis, Concordia University.

abstract:
Spectral descriptors have received much attention in recent years due in large part to their versatility
as well as their ability to capture either local or global geometric information of data. While the overwhelming
majority of work on spectral descriptors has concentrated primarily on image/shape retrieval
and object recognition, the goal of this work is to introduce efficient algorithms for data classification
and clustering in the spectral graph-theoretic setting. In addition to exploiting the dependence among
the features of spectral descriptors, we perform clustering and classification on sparse codes, thereby
seamlessly capturing the similarity between these features.
Unlike classification in which objects are assigned to predefined classes, clustering is different
in the sense that the number (and labels) of clusters or the cluster structure are not known in advance.
In this thesis, we propose a spectral graph-theoretic clustering and classification framework,
called GraphFDD, which uses the Fermi density descriptor (FDD) in conjunction with graph regularized
sparse coding. We also propose a unified framework for data clustering using the spectral graph
wavelet descriptor, which has a strong discriminative power and good performance in capturing neighborhood
information. To further enhance the effectiveness of the proposed algorithms, we not only
optimize the parameters, but also determine the proper matching normalization technique.
To assess the performance of the proposed algorithms, we use several validity measures and indices,
including the average clustering accuracy, normalized mutual information, confusion matrix
and classification accuracy. Our experiments on different standard benchmarks not only show that the
proposed approaches outperform state-of-the-art methods, but also provide attractive scalability and
robustness in terms of computational efficiency.


identifier: Sarma, Shrabani  (2016) Removal of nutrients and suspended solids from a eutrophic lake.  Masters thesis, Concordia University.

abstract: Eutrophication, the rapid growth of blue green algae in surface water, has become an environmental issue worldwide. In Canada, it has been also identified as one of the leading risks to surface water quality especially lake water quality. Lake Caron, an artificial lake, located in the municipality of Saint-Anne Des Lacs, Quebec, has been suffering from eutrophication due to high concentrations of nutrients and chlorophyll α since 2008. The objectives of the study are to evaluate the water quality parameters of a eutrophic lake, to treat eutrophic lake water samples by filtration using non-woven geotextiles and hence evaluate the effectiveness of non-woven geotextiles as a filter media, and assess the relationship among various water quality parameters. To achieve these objectives, water samples from the lake were analysed for two consecutive years. Further, a small scale field experiment was conducted beside the lake by using non-woven geotextiles as filter media. Custom made geotextiles of distinct apparent opening sizes and materials (TE-GTX300 – 110 µm, TE-GTN300 – 90 µm, TE-GTN350 – 90 µm and TE-GTN340 - 75 µm) were used in different combinations to find the best combination providing maximum efficiency in removing nutrients and suspended solids to achieve acceptable level within shorter period of time. Several combinations of geotextile filters were tried for different initial turbidity range of lake water. For an initial turbidity ranging from 4 to 9 NTU, filtration with the combination of 2 layers of 110 μm (TE-GTX300) followed by 3 layers of 90 μm (TE-GTN350) showed the best result at 7th day of filtration, whereas filtration with a filter media consisting of 2 layers of 110 μm (TE-GTX300) and 3 layers of 75 μm (TE-GTN340) geotextiles had been found to restore the water quality at the 3rd day of filtration for an initial turbidity ranging from 9 to 14 NTU. The combination of 1 layer of 110 μm (TE-GTX300) with 4 layers of 90 μm (TE-GTN300) showed the best result at 2nd day during filtration for an initial turbidity higher than 14 NTU. For the first two category (4 to 9 NTU and 9 to 14 NTU) the removal efficiencies were 66, 100 and 96% for removing total P (TP), TSS and turbidity, respectively. For the remaining categories (14 to 19 NTU and higher than 19 NTU), the removal efficiencies were more than 90% for TP and turbidity and more than 96% efficiency had been found in case of TSS removal. TSS removal correlates with the reduction of turbidity, TP and COD concentration. Initial flow rates through the filter decrease with increasing number of filter layers and decreasing pore size of the filter media. A higher TSS decreases the flow rate through the filter and increases clogging. Geotextiles as a filter media have shown potential for improvement of surface water quality in terms of nutrients, turbidity and TSS removal.


identifier: Wanjiku, John Gitonga  (2015) HIGH FLUX DENSITY ROTATIONAL CORE LOSS MEASUREMENTS.  PhD thesis, Concordia University.

abstract:
Energy conversion processes involve losses. Specifically core losses, which are a result of the magnetization process in cored electrical energy conversion and storage devices. The cores are made of soft ferromagnetic materials that are easily magnetized and demagnetized. These soft magnetic cores, allow a reduction in size, higher energy storage density, and a reduction in magnetizing current, when compared to non-cored devices.
The characterization of soft ferromagnetic materials is traditionally done under unidirectional pulsating fields, which is sufficient for single-phase transformers and inductors, where the cores are under pulsating fields. However, T-joints of three phase transformers and teeth-roots of rotating machine stator cores are exposed to two-dimensional rotational fields of higher core loss. Pulsating measurements are therefore insufficient in the characterization of soft ferromagnetic materials used in rotating electrical machines or in three phase transformers. In two-dimensional fields, the magnetization direction changes with time, tracing a flux density locus. This requires the measurement of tangential magnetic field and flux density components, hence the associated loss.
This study proposes a two-dimensional rotational core loss tester for high flux density measurements up to about 2 T, at 60 Hz. Its frequency measurement range is from 60 Hz to 1 kHz. The initial sizing was done analytically, then implemented in three-dimensional finite element analysis, prototyped and experiments performed to verify its capability.
It was validated by testing two 0.35 mm and 0.65 mm thick samples. Very high flux densities in the range of 2 T at 60 Hz were achieved in both samples. For the thinner sample, flux densities of 1.8 T and 1.6 T were measured at 400 Hz and 1 kHz, respectively, while for the thicker one, the range reduced to 1.7 T and 1.4 T, at 400 Hz and 1 kHz, respectively. The magnetizer also reproduced non-sinusoidal flux density waveforms, for flux densities less than or equal to 1.0 T, without any waveform control.
The proposed rotational core loss setup will find application in the characterization of electrical steels, and generation of pulsating and rotational core loss data. This data can then be applied in core loss models, uprating of megawatt (MW) rated machines, transient and hotspots analysis, and in the design of higher power density machines, such as high-speed machines.


identifier: Jafrin, Rifat  (2015) Data Annotation and Ontology Provisioning for Semantic Applications in Virtualized Wireless Sensor Networks.  Masters thesis, Concordia University.

abstract:
In recent years, virtualization in Wireless Sensor Networks (WSNs) has become very popular for many reasons including efficient resource management, proper sharing and using the same WSN physical infrastructure by multiple applications and services. Semantic applications are very much pertinent to provide situational awareness to the end-users. Incorporating semantic applications in the virtualized WSNs can play a crucial role in providing contextual information to understand the situation, increase usability and interoperability. However, provisioning of semantic applications in virtualized WSNs remains as a big challenge. The reason is the data collected by the virtual sensors needs to be annotated in-network, and the pre-requisite of the data annotation process is to have an ontology that needs to be provisioned, i.e., developed, deployed and managed. Unfortunately, annotating sensor data and ontology provisioning in virtualized WSNs is not straightforward because of limited resources of sensors, on-demand creation of virtual sensors, and unpredictable lifetime. As the existing researches do not consider data annotation in virtualized WSN infrastructure level, these solutions are domain specific and lack of providing support for multiple applications. Moreover, the major drawback of the current ontology provisioning mechanisms requires domain experts to develop, deploy, and manage the ontologies in WSNs.   This thesis aims to propose a solution for provisioning of multiple semantic applications in the virtualized WSNs.
The main contribution of this thesis is twofold. First, we have proposed an architecture to annotate sensor data in the virtualized WSN infrastructure and defined an ontology in sensor domain to perform data annotation. Second, we have proposed an architecture for provisioning ontology in the virtualized WSNs that consists of an ontology provisioning center, an ontology-enabled virtualized WSN, and an ontology deployment protocol. The proposed architectures use overlay network as a foundation. We have built a proof-of-concept prototype for a semantic wildfire monitoring application in the cloud environment using the Google App Engine. In order to evaluate the viability of the proposed architecture, we have made performance measurement of the implemented prototype. We ran a simulation to justify our proposed ontology provisioning protocol.


identifier: Haist Jr., Michael  (2016) On Ecclesiology, “The Holy Spirit and the Upbuilding of the Christian Community,” Karl Barth in Dialogue with the Thought of Joseph Ratzinger.  Masters thesis, Concordia University.

abstract:
ABSTRACT

On Ecclesiology in “The Holy Spirit and the Upbuilding of the Christian Community”
Karl Barth in Dialogue with the Thought of Joseph Ratzinger

Michael Haist Jr.

	This thesis is a dialogue between Karl Barth and Joseph Ratzinger on the topic of ecclesiology. The thesis follows the format of section 67 of Barth's Church Dogmatics, which deals with principles of ecclesiology in the context of the Doctrine of Reconciliation. The question this thesis addresses is whether there is any continuity between the thought of the two figures on certain topics of ecclesiology that are covered by this section of CD. There are several issues on which they agree. On the final topic, Church law, Barth suggests that laws held by different communities can be true despite being potentially contradictory. This paper posits that Ratzinger is in agreement with Barth on this last point.


identifier: Senn, Jessica M.  (2015) An Examination of Distraction Use in Exposure Therapy for Anxiety.  PhD thesis, Concordia University.

abstract: Individuals often utilize distraction strategies to cope with distress that results from anxiety-provoking situations.  While some theories suggest that distraction will impede improvement during exposure, others suggest it may not be harmful, and may in fact aid in fear reduction.  Experimental results parallel these divergent theories, with support for distraction both helping and hindering treatment.  Given these mixed findings, the goal of these studies was to investigate factors that may help explain the differences observed in the extant literature.  In Study 1 a measure of maladaptive beliefs about distraction, the Beliefs about Distraction Inventory (BADI), was developed and validated in an unselected student sample (N = 506) and confirmed in a contamination-fearful sample (N = 132).  Results indicated that the BADI was psychometrically sound and consisted of two factors: Distraction is Necessary and Distraction is Effective.  This factor structure was confirmed in the contamination-fearful sample, and similar psychometric properties were observed.  Study 2 was comprised of two studies that together aimed to assess the impact of differing levels of distraction on exposure outcome.  In Experiment 1 verbal distraction tasks were experimentally validated in an undergraduate sample (N = 180) using a reaction time task.  Three different levels of distraction were established, categorized as utilizing low, moderate, and high levels of cognitive load.  In Experiment 2 the three tasks varying in distraction intensity were compared to a no distraction control during an exposure session with contamination-fearful individuals (N = 124).  Changes in behavioural approach did not differ significantly across conditions at post-exposure or at one-week follow-up.  However, treatment acceptability was highest in conditions utilizing moderate or high levels of distraction, and changes in self-efficacy were greatest in the moderate distraction condition.  Finally, preliminary analyses were conducted to assess the impact of maladaptive beliefs about distraction on exposure outcome.  Results showed that high BADI scores were related to less improvement over the course of an exposure session when moderate distraction was utilized.  The results of these studies are discussed in terms of theoretical and clinical implications, including the cognitive-behavioural treatment of anxiety and related disorders.